Part3 Geology of the Sheeprock Mountains, Tooele and Juab Counties, Utah

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Part3 Geology of the Sheeprock Mountains, Tooele and Juab Counties, Utah

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Title	Geology of the Sheeprock Mountains, Tooele and Juab Counties, Utah
Publication Type	thesis
School or College	College of Mines & Earth Sciences
Department	Geology & Geophysics
Author	Cohenour, Robert E.
Date	1957-08
Description	The Sheeprock Range, Tooele and Juab Counties, Utah, is composed chiefly of consolidated sedimentary rocks of Precambrian and Paleozoic age. Several areas of both intrusive and extrusive rocks are present. Unconsolidated sediments related to late Tertiary and Quaternary episodes cover much of the flanks of the range as pediment gravels, lake deposits, and alluvium. Nearly 11,000 feet of Precambrian metasediments, largely slates and quartzites similar to late Precambrian formations in central and western Utah, crop out in the central part of the area. Tillites similar to those found locally in the Wasatch Mountains are the thickest and most distinctive of the Precambrian rocks. Twenty-seven formations having a combined thickness of approximately 20,000 feet represent the Paleozoic era and include rocks of all Paleozoic periods excepting (?) Permian. Over 80 percent of the Paleozoic rocks are of marine origin, the remainder are continental-interior-shelf and shoreline deposits. Limestone, dolomite, quartzite, and shale typical of miogeosynclinal environment constitute the Paleozoic rock types. Excepting minor hiatuses, continuous sedimentation prevailed from Precambrian into Pennsylvanian. All formations were strongly folded and broken by thrust faults during the Laramide orogeny. Rock units necessary for precise relative dating of Laramide and later orogenic events are not present in the Sheeprock Range, but the relationships of preserved structures permit the establishment of a sequence of deformational phases as follows: (1) Cedar Hills orogeny(?) - Mid-Cretaceous phase, (2) Early Laramide orogeny - Montana phase, (3) Mid-Laramide orogeny (?) - Paleocene phase, (4) Late Laramide orogeny, and (5) Basin and Range phase. Structures formed during these phases include folds, thrust faults and imbrications, and normal faults, and the structures of each successive phase are superposed upon those of earlier phases. Igneous activity which began in early Tertiary and continued into Miocene formed granitic and monzonitic intrusions and extensive rhyolitic and andesitic flows. A single small area of basalt of undetermined age is present. The resulting structure of the Sheeprock Range is essentially a northward-dipping homocline modified by several folds, major thrusts, and intrusions. Normal faulting of the Basin and Range orogenic phase, concomitant with and following the igneous activity, affected both Tertiary and older rocks and is primarily responsible for the present topography and out¬ line of the Sheeprock Range. Lake Bonneville shoreline features along the western part of the area and a questionable morainal deposit at the mouth of North Oak Brush Canyon represent Pleistocene events. Mineral deposits fall into two major groups: (1) deposits associated with the West Tintic monzonite cutting Precambrian and Paleozoic rocks have yielded minor quantities of commercial ores of lead, zinc, silver, gold, and tungsten; (2) deposits associated with the Sheeprock granite have yielded ores and protores of beryllium, lead, silver, tungsten, thorium, and uranium, but none of these has achieved commercial significance.
Type	Text
Publisher	University of Utah
Subject	Geology -- Utah -- Sheeprock Mountains; Geology -- Utah -- Tooele County; Geology -- Utah -- Juab County; Thesis and dissertation georeferencing project
Dissertation Institution	University of Utah
Dissertation Name	Doctor of Philosophy
Language	eng
Relation is Version of	Digital reproduction of Geology of the Sheeprock Mountains, Tooele and Juab Counties, Utah, J. Willard Marriott Library Special Collections, QE 3.5 1957 C64
Rights Management	In the public domain use of this file is allowed in accordance with the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License, http://creativecommons.org/licenses/by-nc-nd/3.0/us
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Identifier	us-etd3,10495
Source	Original: University of Utah J. Willard Marriott Library Special Collections
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ARK	ark:/87278/s6668v18
DOI	https://doi.org/doi:10.26053/0H-9ZCG-T4G0
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ID	195351
Reference URL	https://collections.lib.utah.edu/ark:/87278/s6668v18

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Title	Part3 Geology of the Sheeprock Mountains, Tooele and Juab Counties, Utah
Description	Part 3 contains pages 82-138 of thesis.
Type	Text
Relation is Version of	Digital reproduction of Part3 (pgs. 82-138) from Geology of the Sheeprock Mountains, Tooele and Juab Counties, Utah, J. Willard Marriott Library Special Collections, QE 3.5 1957 C64
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ID	195346
OCR Text	Show 82 I n t h e S h e e p r o c k M o u n t a i n s a t r i i o b i t e ( ? ) t r a c k was found 40 f e e t a b o v e the b a s e of t h e P i o c h e s h a l e in m a t e r i a l s i m i l a r to t h a t of t h e O p h i r f o r m a t i o n in t h e O q u i r r h M o u n t a i n s , with t h e e x c e p t i on t h a t at the S h e e p r o c k s e c t i o n the m a t e r i a l i s a b u n d a n t l y f u c o i d a i. T h e n e x t f a u n u l e in t h e S h e e p r o c k M o u n t a i n s was c o l l e c t e d 351 f e e t a b o v e the top of the T i n t i c q u a r t z i t e , in a l i m e s t o n e u n i t within t h e s t r a t a a s s i g n e d to t h e B u s b y f o r m a t i o n . The f a u n a i s m o st c h a r a c t e r i s t i c of t h e A l b e r t e l l a zone of t h e s t a n d a r d s e c t i o n . All C a m b r i a n f a u n a l c o r r e l a t i o n s w e r e m a d e in a c c o r d a n c e with the s t a n d a r d c o r r e l a t i o n c h a r t (Howell, et a l . , 1944). The s t a n d a rd c o r r e l a t i o n c h a r t was u s e d b e c a u s e of t h e p r e s e n t d i s a g r e e m e n t in the z o n a t i o n of t h e C a m b r i a n in t h e w e s t e r n U n i t e d S t a t e s. No u n c o n f o r m i t y c o u l d be d e m o n s t r a t e d within t h e s h a l e s e q u e n ce b e l o w t h e A l b e r t e l l a zone n o r in t h e c a r b o n a t e s a b o v e. T h e f o s s i l s a r e p r e s e n t i n l i m e s t o n e s of the B u s b y f o r m a t i on o v e r l y i n g about 30 f e e t of g r a y i s h - t a n d o l o m i t e , a l s o of t h e B u s by f o r m a t i o n . However, both e a s t and w e s t of the f o s s i l l o c a l i t y a 3 0 - to 5 0 - f o o t d a r k r e d d i s h - b r o w n q u a r t z i t e o v e r l i e s t h e d o l o m i t e. W h e t h e r o r not t h e q u a r t z i t e s r e p r e s e n t an u n c o n f o r m i t y c o u ld not be d e m o n s t r a t e d . They do i n d i c a t e t h a t a s o u r c e was n e a r b y and t h a t the s o u r c e was p o s i t i v e in e a r l i e s t m e d i a l C a m b r i a n . The w r i t e r b e l i e v e s that t h i s p o s i t i v e a r e a was e i t h e r to t h e n o r t h o r e a st but r e c o g n i z e s t h a t it m a y h a v e b e e n l o c a l , s i n c e only 60 to 90 f e et 83 of r e l i e f n e e d be a v a i l a b l e to p r o v i d e an e x p o s u r e of T i n t i c. McKee (1945) h a s d e m o n s t r a t e d t h a t t e m p o r a r y r e g r e s s i o n i s in t h e m a i n r e s p o n s i b l e for the f o r m a t i o n of s t r a y q u a r t z i t e s . The f o s s i l s r e c o v e r e d by G i l l u l y f r o m the O p h i r s h a l e s a r e m o s t ly l i k e l y r e p r e s e n t a t i v e of t h e A l b e r t e l l a or a y o u n g e r z o n e . If t h is i s t r u e f o r m a t e r i a l c o l l e c t e d 50 f e e t a b o v e the b a s e of the O p h ir i n the O q u i r r h M o u n t a i n s , and if t h e a s s i g n m e n t of t h e o l d er A l b e r t e l l a z o n e f o r m a t e r i a l p r o c u r e d 351 f e e t above i t s s t r a t i g r a p h ic e q u i v a l e n t in t h e S h e e p r o c k s i s v a l i d , then i t would be m o s t l o g i c al to a s s u m e t h a t a h i g h l a n d o r p r o m o n t o r y e x i s t e d n o r t h e a s t of the S h e e p r o c k M o u n t a i n s in e a r l y Middle C a m b r i a n t i m e . A h i g h l a nd i s n e c e s s a r y b e c a u s e the f a u n a found by G i l l u l y not only r e p r e s e n ts a y o u n g e r f a u n a l z o n e , but a l s o one which i s 50 f e e t a b o v e t h e T i n t ic q u a r t z i t e , w h e r e a s t h e S h e e p r o c k f a u n a i s o l d e r and i s 350 f e e t above t h e T i n t i c . The w r i t e r g u e s s e s t h a t the h i g h l a n d i m m e d i a t e ly a f f e c t i n g the S h e e p r o c k s e d i m e n t a r y e n v i r o n m e n t s was m o s t l i k e ly a p e n i n s u l a - l i k e p r o m i n e n c e which e x t e n d e d f r o m the W a s a t ch s h e l f a r e a w e s t w a r d t o w a r d Gold H i l l . T h i s p r o p o s e d h e a d l a nd o r r e l a t i v e l y p o s i t i v e a r e a m o s t l i k e l y p a r t i a l l y s e p a r a t e d the e a s t e rn p a r t of the C o r d i l l e r o - C a m b r i a n t r o u g h i n t o n o r t h e r n and s o u t h e rn e m b a y m e n t s with r e l a t i v e l y d e e p ( I s o s t a t i c a l l y n e g a t i v e ) c o n n e c t i o ns t h r o u g h the Gold H i l l r e g i o n . If t h i s i s v a l i d , then it would s e em t h a t t h e B l a c k s m i t h F o r k and n o r t h e r n Utah e a r l y M i d d l e C a m b r i an 84 s t r a t a would be l i t h o l o g i c a l l y and f a u n a l l y m o r e l i k e H o u s e R a n ge s e c t i o n t h a n e i t h e r the C a m b r i a n s t r a t a of t h e O q u i r r h M o u n t a i ns o r the C e n t r a l W a s a t c h M o u n t a i n s . This c o n d i t i o n of s i m i l a r i ty would e x i s t u n t i l t h e s a l i e n t was e r a s e d which p r o b a b l y o c c u r r ed in l a t e M i d d l e C a m b r i a n t i m e . By l a t e M i d d l e C a m b r i a n t i m e, s i m i l a r e n v i r o n m e n t a l c o n d i t i o n s p r e v a i l e d o v e r t h e e n t i r e a r e a. The w r i t e r b e l i e v e s t h a t s u c h an e n v i r o n m e n t , which p e r s i s t ed d u r i n g W h e e l e r t i m e , must h a v e b e e n e f f e c t i v e o v e r a wide a r e a. The W h e e l e r , to p o s s e s s i t s b e d d i n g p a r a l l e l i s m ( v a r v e s ) , e i t h er h a d to be d e p o s i t e d b e l o w wave b a s e o r e l s e c o n d i t i o n s w e re e x t r e m e l y q u i e t (no w i n d ) . Total t h i c k n e s s of t h e U p p e r C a m b r i an s t r a t a i n d i c a t e s t h a t all of t h e s e c t i o n s w e r e r e c e i v i n g s e d i m e n t s at n e a r l y t h e s a m e r a t e e x c e p t i n g t h o s e t h i c k e r s e c t i o n s which p o s s e s s e d a 1 m o m e n t u r n - o f - s i n k i n g ' p r o b a b l y b e c a u s e of an e a r l i er s t a r t and a g r e a t e r weight of s e d i m e n t s ( t h e weight of the s e d i m e n ts a c t i n g i s o s t a t i c a l l y a n d p r o m o t i n g d i f f e r e n t i a l c o m p a c t i o n ) . In light of p r e s e n t day w e a t h e r p h e n o m e n a , i t would s e e m u n r e a s o n a b l e to a s s u me t h a t a c o n d i t i o n of v i o l e n t w e a t h e r c o u l d p e r s i s t l o c a l l y without a f f e c t i n g the s e d i m e n t a r y e n v i r o n m e n t of v a s t p o r t i o n s of t h e s u r r o u n d i n g a r e a . This i s e s p e c i a l l y s i g n i f i c a n t s i n c e l a m i n a e u s u a l ly i n d i c a t e i n u n d a t i o n and q u i e s c e n c e . The o o l i t e s p r e s e n t in the D a g m a r l i m e s t o n e and t h e H a r t m a n n l i m e s t o n e would m e r e ly i n d i c a t e s h a l l o w e r w a t e r with s u f f i c i e n t c u r r e n t and wave a c t i v i ty 85 t o a l l ow the CO2 to e s c a p e and to d i s t u r b , by r o i l i n g , the n u c l e i of of c a r b o n a t e d e p o s i t i o n. D u r i n g L a t e C a m b r i a n t i m e t h e p h y s i c a l and c h e m i c a l f a c t o rs e f f e c t i n g s e d i m e n t a t i o n w e r e s i m i l a r f o r m o s t of the g e o s y n c l l n al a r e a ; c o n s e q u e n t l y , c o r r e l a t i o n of s t r a t a by l i t h o l o g y and p a l e o n t o l o gy s h o u l d be m o r e a c c u r a t e. C a m b r i a n - O r d o v i c i a n c o n t a ct T h e C a m b r i a n - O r d o v i c i a n b o u n d a r y in t h e S h e e p r o c k M o u n t a i ns a p p e a r s to b e c o n f o r m a b l e and m a r k e d by c o n t i n u o u s s e d i m e n t a t i on a c r o s s t h e t i m e l i n e . The c h o s e n c o n t a c t i s s h a r p a n d i s p l a c e d at t h e top of t h e d a r k e r , m o r e m a s s i v e , c r y s t a l l i n e d o l o m i t e of t h e A j a x. T h e O r d o v i c i a n , House l i m e s t o n e , i s a b l u e - g r a y , m e d i u m - b e d d e d, i n t r a f o r m a t i o n a l l i m e s t o n e . Sufficient c o n t r a s t in b o t h t e x t u r e and c o l o r e x i s t s to e n a b l e one t o d i f f e r e n t i a t e the two w h e r e v e r t h e y a re f o u n d . The H o u s e l i m e s t o n e c o n t a i n s s i l t and a l i t t l e c h e r t in i ts b a s a l u n i t s , w h e r e a s the u p p e r m o s t s t r a t a of t h e A j a x a r e m a s s i v e, c h e r t l e s s , and i n d i s t i n c t l y l a m i n a t e d . The C a m b r i a n - O r d o v i c i an c o n t a c t was c h o s e n on t h e b a s i s of d i f f e r i n g i i t h o i o g i e s which s e e ms t o c o r r e l a t e with t h o s e o b s e r v e d in t h e E a s t T i n t i c M o u n t a i n s b e t w e e n the A j a x and the O p o h o n g a l i m e s t o n e of E a r l y O r d o v i c i a n a g e . In the m i o g e o s y n c l i n a l f a c i e s of t h e L o w e r O r d o v i c i a n f o r m a t i o n s of Utah, t h e P o g o n i p g r o u p a n d t h e m o r e n o r t h e r l y G a r d e n C i t y l i m e s t o ne b o t h c o n t a i n a g r e a t t h i c k n e s s of i n t r a f o r m a t i o n a l c o n g l o m e r a t es 86 ( r e l a t i v e to any r o c k s y s t e m s b e f o r e o r s i n c e L o w e r O r d o v i c i a n in t h e e a s t e r n B a s i n and R a n g e p r o v i n c e ) . T h e r e f o r e , on t h e b a s i s of s i m i l a r l i t h o l o g y b e t w e e n p r o v e n O r d o v i c i a n ( C a n a d i a n ) s e c t i o ns i n b o t h t h e C o n f u s i o n B a s i n and n o r t h e r n Utah, the b a s a l O r d o v i c i an s t r a t a w e r e r e c o g n i z e d. 87 ORDOVICIAN SYSTEM G e n e r a l s t a t e m e nt T h e O r d o v i c i a n s y s t e m i s r e p r e s e n t e d by o v e r 3, 086 f e e t of s t r a t a . L i m e s t o n e , d o l o m i t e , q u a r t z i t e , and s h a l e r e p r e s e n t the s y s t e m and a r e in t h e s a m e o r d e r of a b u n d a n c e . T h e l o w e r p a rt of t h e s y s t e m i s n e a r l y a l l l i m e s t o n e and r e p r e s e n t s t h e t h i c k e st p o r t i o n of O r d o v i c i a n r o c k s in t h e a r e a . F i v e f o r m a t i o n s a re r e c o g n i z e d a s m a p p a b l e u n i t s a n d w e r e c o r r e l a t e d with t h e T i n t ic a n d I b e x H i l l s s e c t i o n s . Capping the l i m e s i s a s h a l e which, t o g e t h er with t h e u p p e r p o r t i o n of t h e u n d e r l y i n g l i m e s t o n e , i s t h e m o st f o s s i l i f e r o u s s t r a t u m in t h e O r d o v i c i a n . Between 200 a n d 400 f e et of q u a r t z i t e o v e r l i e s the s h a l e a n d i s i n t u r n c o n f o r m a b l y o v e r l a in by t h e d a r k c h e r t y U p p e r O r d o v i c i a n d o l o m i t e s , which g r a d e i n t o the l i g h t e r m a g n e s i u m r o c k s t e n t a t i v e l y a s s i g n e d to t h e S i l u r i a n. O r d o v i c i a n t e r m i n o l o g y i s c o n f u s i n g . The P o g o n i p , C h o k e c h e r r y, G a r d e n C i t y , Opohonga, and f o u r n e w l y n a m e d f o r m a t i o n s f r o m the I b e x a r e a a l l a p p e a r to c o r r e l a t e with t h e S h e e p r o c k s e c t i o n . The S h e e p r o c k M o u n t a i n r e g i o n r e p r e s e n t s t h e hub i n t o which t h e s e n a m es a r e c o n v e r g i n g - a l l m a y b e r e c o g n i z e d . S e v e r a l c o u r s e s m a y be f o l l o w e d : (1) a b a n d o n a l l p r e v i o u s n a m e s and p r o p o s e n e w o n e s , (2) a c c e p t one o r m o r e of t h e p r e v i o u s l y u s e d n a m e s , or (3) c o n s i d er t h e s t r a t a a s u n d i f f e r e n t i a t e d . A n e w n a m e would only a d d m o r e c o n f u s i o n to t h e p r o b l e m. 88 P o g o n i p , the o l d e s t n a m e , was u s e d b e c a u s e it i n c l u d ed U p p e r C a m b r i a n in i t s l o w e r p a r t ; h o w e v e r , P o g o n i p ' r e s t r i c t e d9 would a p p l y if t h e S h e e p r o c k s e q u e n c e c o u l d not b e c l e a r l y s u b d i v i d e d . C h o k e c h e r r y d o l o m i t e c a n n o t c o r r e l a t e b e c a u s e it r e p r e s e n ts o n l y a p a r t of t h e L o w e r O r d o v i c i a n in q u e s t i o n , h a v i n g an u n c o n f o r m i ty a t t h e t o p . F u r t h e r m o r e , lack of a d e q u a t e p a l e o n t o l o g y l e a v e s d a t i ng of t h e C h o k e c h e r r y v e r y q u e s t i o n a b l e . The f o r m a t i o n m a y be in p a rt U p p e r C a m b r i a n. T h e t e r m Opohonga l i m e s t o n e i s a l s o u n d e s i r a b l e b e c a u s e of an u n c o n f o r m i t y at t h e t o p of t h e unit in t h e a r e a of t h e t y p e s e c t i on ( E a s t T i n t i c M o u n t a i n s ) . The G a r d e n C i t y r e p r e s e n t s a l o n g e r s p an but i s not s u b d i v i d e d , e x c e p t p a l e o n t o l o g i c a i l y , and i s e x c l u d e d. T h e I b e x s e c t i o n , which i n c l u d e s t h e H o u s e , F i l l m o r e , Wah Wah, a n d J u a b l i m e s t o n e s , i s p r o b a b l y the b e s t g r o u p with which to c o r r e l a te s i n c e the s e c t i o n i s l i t h o l o g i c a l l y s u b d i v i d e d and a d e q u a t e l y z o n e d by t r i l o b i t e s . Except f o r t h e p r e s e n c e of c h e r t , the H o u s e and F i l l m o re l i m e s t o n e s a r e d i f f i c u l t to d i f f e r e n t i a t e in t h e S h e e p r o c k a r e a . D i s t i n c t i v e r e c o g n i z a b l e f o s s i l s w e r e not found in t h i s i n t e r v a l , but the w r i t e r b e l i e v e s t h e i n t e r v a l c a n be z o n e d by c a r e f u l c o l l e c t i o n and s t u d y . The u p p e r two f o r m a t i o n s a r e e a s i l y r e c o g n i z e d l i t h o l o g i c a l ly and t h e c o n t a c t s c a n b e e a s i l y t r a c e d. 89 T h e Swan P e a k - E u r e k a q u a r t z i t e was i s o p a c h e d ( F i g u r e 5) f o r v a r i o u s l o c a l i t i e s in U t a h , N e v a d a , and I d a h o . I n c l u d e d with t h e t h i c k n e s s of q u a r t z i t e i s t h e C r y s t a l P e a k d o l o m i t e . The i s o p a c h o u s l i n e s a p p e a r to f o l l ow t r o u g h s of t h e C a m b r i a n and L o w er O r d o v i c i a n i n t e r v a l s . The w r i t e r b e l i e v e s t h a t t h i s t h i c k n e s s is m o r e a r e f l e c t i o n of t h e d i f f e r e n t i a l c o m p a c t i o n of t h e t h i c k e r p r e e x i s t i n g r o c k s of C a m b r i a n and O r d o v i c i a n t i m e s t h a n it i s of a n e g a t i v e t e n d e n c y of t h e g e o s y n c l i n e. F i s h Haven l i t h o l o g y was e a s i l y r e c o g n i z e d and c a n be t r a c ed with e a s e . However, the F i s h H a v e n - L a k e t o w n c o n t a c t i s p l a c e d only by a r b i t r a r y d e c i s i o n. H o u s e and F i l l m o r e f o r m a t i o n s u n d i f f e r e n t i a t ed D i s t r i b u t i o n and t h i c k n e s s - The H o u s e and F i l l m o r e f o r m a t i o ns c r o p out in b o t h t h e E a s t and West L o o k o u t H i l l s a b o u t one m i l e n o r th of t h e s o u t h end of the h i l l s . The s t r a t a t r a v e r s e t h e c o u n t r y in a n o r t h w e s t e r l y d i r e c t i o n and a r e cut i n t h e West L o o k o u t H i l l s by s e v e r a l f a u l t s . Small o u t c r o p s of t h e u p p e r p a r t of t h e F i l l m o r e a re p r e s e n t in t h e e a s t e r n p o r t i o n of t h e S i m p s o n M o u n t a i n s n o r t h w e st a n d west of B l a c k ' s R a n c h. T h e H o u s e and F i l l m o r e f o r m a t i o n s w e r e m e a s u r e d In b o t h t he E a s t and West L o o k o u t H i l l s , b e i n g 1 , 1 1 1 and 1, 0 8 8 f e e t t h i c k, r e s p e c t i v e l y (Appendix A a n d P l a t e s III and XX). 90 T o p o g r a p h i c e x p r e s s i o n - The H o u s e and F i l l m o r e f o r m a t i o ns g e n e r a l l y a r e m o d e r a t e l y r e s i s t a n t to e r o s i o n ; t h e m o r e s l a b b y b e ds w e a t h e r to f o r m s a d d l e s while m o r e m a s s i v e b e d s f o r m r i d g e s and c l i f f s . L i t h o l o g y - The b a s e of t h e H o u s e - F i l l m o r e f o r m a t i o n is a r b i t r a r i l y p l a c e d at a p o i n t w h e r e the t h i n - b e d d e d , flaggy, b l u e - g r a y d o l o m i t e s of t h e c o n f o r m a b l y u n d e r l y i n g Ajax f o r m a t i o n b e c a me c a l c a r e o u s . The b a s a l b e d s of t h e H o u s e l i m e s t o n e a r e c h a r a c t e r i s t i c a l ly s l a b b y with t a n s i l t y m o t t l i n g and s l i g h t l y u n d u l a t o r y p a r t i n g s and r e s e m b l e m u c h of t h e s t r a t a in t h e u p p e r p a r t of t h e Opex f o r m a t i o n. Some i n t r a f o r m a t i o n a l c o n g l o m e r a t e b e d s a r e p r e s e n t . Though the H o u s e and F i l l m o r e l i m e s t o n e s w e r e not d i f f e r e n t i a t e d and m a p p ed a s s e p a r a t e u n i t s , the w r i t e r b e l i e v e s t h a t t h e H o u s e l i m e s t o n e p r o b a b l y r e p r e s e n t s the l o w e r 160 f e e t of t h e 1, 0 8 8 f e e t of s t r a t a a s s i g n ed to t h e H o u s e - F i l l m o r e s e q u e n c e . The t o p ( ^ ) of t h e H o u s e l i m e s t o n e is r e p r e s e n t e d by 23 f e e t of m e d i u m - b e d d e d , b l u e - g r a y , c h e r t y l i m e s t o n e s . The c h e r t s a r e s m o o t h and r o u n d e d ; t h e y a r e g r a y when f r e s h , tan when w e a t h e r e d. I n t r a f o r m a t i o n a l c o n g l o m e r a t e s c o m p r i s e o v e r 80 p e r c e n t of the r e m a i n i n g 928 f e e t of the H o u s e - F i l l m o r e s e q u e n c e ( P l a t e XVIII). G e n e r a l l y t h e s e c o n g l o m e r a t e s a r e m e d i u m - b e d d e d with s o m e thin b e d s . Close i n s p e c t i o n i s n e c e s s a r y to d e t e c t t h e i n t r a f o r m a t i o n al c h a r a c t e r of m a n y of t h e b e d s . Near t h e top p o o r l y p r e s e r v ed Figure I View of the House limestone in the West Lookout Hills conformably overlying the covered Upper Cambrian, Ajax dolomite in the foreground. Figure 2 Hand specimen of the intraformational limestone conglomerate from the House and Fillmore formations. 91 t r i i o b i t e p a r t s and u n i d e n t i f i a b l e g a s t r o p o d a n d b r a c h i o p o d f r a g m e n t s a r e p r e s e n t , e s p e c i a l l y in a c a l c a r e o u s , s i l t y , pink, f i n e g r a i n e d m a t r i x , N e a r l y a l l t h e p e b b l e s in t h e s e c o n g l o m e r a t es a r e t a b u l a r with r o u n d e d e d g e s b o t h in s e c t i o n and p l a n v i e w s , and m a n y of t h e p e b b l e s a r e thin and t h e i r b e d d i n g c a n b e m a t c h e d with t h e b e d d i n g in a d j a c e n t p e b b l e s. F i e l d i d e n t i f i c a t i o n - I n t r a f o r m a t i o n a l l i m e s t o n e c o n g l o m e r a t es a r e m o r e p r o m i n e n t and n u m e r o u s in t h e H o u s e and F i l l m o r e f o r m a t i o n s t h a n i n any o t h e r s t r a t a i n t h e S h e e p r o c k r e g i o n . C h a r a c t e r i s t i c a l l y the pebbLe c o n s t i t u e n t s a r e t a b u l a r with r o u n d e d e d g e s and a re e i t h e r a l i g h t e r o r d a r k e r g r a y t h a n t h e e n c l o s i n g m a t r i x which is u s u a l l y f i n e r g r a i n e d . The u p p e r p a r t of t h e H o u s e s t r a t a c o n t a i n a l i t t l e p i n k i s h c h e r t which o c c u r s a s s m a l l l o n g i t u d i n a l m a s s e s s e l d om o v e r one i n c h t h i c k . F r a g m e n t s of f o s s i l s c a n b e o b s e r v e d within the m a t r i x of m a n y of t h e c o n g l o m e r a t e s . The Ajax f o r m a t i o n c o n f o r m a b ly u n d e r l i e s t h e H o u s e f o r m a t i o n and i s a b l u e - g r a y to g r a y , flaggy, m e d i u m - g r a i n e d d o l o m i t e h a v i n g g e n e r a l l y wavy b e d d i n g p l a n e s. The F i l l m o r e f o r m a t i o n g r a d e s i n t o t h e c o n f o r m a b l y o v e r l y i n g Wah Wah f o r m a t i o n which i s r e c o g n i z e d by i t s g e n e r a l l y d a r k e r c o l o r a t i o n, b e i n g m o r e tan and s a n d y with an a b u n d a n c e of r e d d i s h s i l t s. Age and c o r r e l a t i o n - F o s s i l s w e r e r e c o v e r e d at f o u r l o c a l i t i es f r o m the H o u s e - F i l l m o r e s t r a t a ( A p p e n d i x B and P l a t e I I I ) . Uni d e n t i f i a b l e c r i n o i d s t e m s with b r a c h i o p o d , g a s t r o p o d , and t r i i o b i te f r a g m e n t s w e r e r e c o v e r e d. 92 R. C. B r i g h t i d e n t i f i e d the f o l l o w i n g: 0 - 2 , n e a r t h e top of t h e f o r m a t i on P s e u d o c y b e l e s p. Or t h i s s p. O p h i l e t a - l i k e g a s t r o p od C y s t o i d c o l u m n a i s - p l a t es The p r e s e n c e of P s e u d o c y b e l e s p . i n d i c a t e s t h a t t h i s z o n e is e q u i v a l e n t t o t h e H, I, or J z o n e s of H i n t z e ( 1 9 5 2 ) . H i n t z e ' s z o n es B t h r o u g h K r a n g e in age f r o m L o w e r to U p p e r C a n a d i a n. T h e H o u s e - F i l l m o r e f o r m a t i o n i s e q u i v a l e n t i n a g e to m o s t of t h e G a r d e n C i t y f o r m a t i o n of R i c h a r d s o n (1913) i n n o r t h e a s t e rn Utah; to m o s t of t h e l o w e r half of t h e P o g o n i p g r o u p , n a m e l y the Goodwin l i m e s t o n e and p a r t of t h e N i n e Mile f o r m a t i o n of Nolan, M e r r i a m and W i l l i a m s (1956) of t h e E u r e k a , N e v a d a a r e a . The O p o h o n g a l i m e s t o n e of L o u g h l i n (1919) of t h e T i n t i c d i s t r i c t , Utah, i s p r o b a b l y e q u i v a l e n t to p a r t of the House and F i l l m o r e f o r m a t i o ns i n t h e S h e e p r o c k M o u n t a i n s. Wah Wah f o r m a t i on D i s t r i b u t i o n and t h i c k n e s s - The Wah Wah f o r m a t i o n c r o p s out n o r t h of the F i l l m o r e f o r m a t i o n in a b a n d about 300 f e e t wide i n the E a s t and West L o o k o u t H i l l s . Regional d i p i s n o r t h and n o r t h e a s t, and f a u l t i n g h a s d i s p l a c e d the u n i t to t h e n o r t h i n t h e W e s t L o o k o ut H i l l s . Small a r e a s of t h e f o r m a t i o n a r e e x p o s e d in t h e S i m p s on M o u n t a i n s w e s t and n o r t h e a s t of B l a c k ' s R a n c h. 93 M e a s u r e m e n t s of t h e Wah Wah f o r m a t i o n i n d i c a t e d 456 f e et in t h e E a s t L o o k o u t H I i i s and 475 f e e t in t h e West Lookout H i l ls ( A p p e n d i x A and P l a t e I I I ) . No t h i n n i n g was n o t e d in t h e S h e e p r o c k - S i m p s o n a r e a. T o p o g r a p h i c e x p r e s s i o n - Sands w i t h i n t h e Wah Wah f o r m a t i o n, t o g e t h e r with s o m e s e c o n d a r y c h e r t , e n a b l e the f o r m a t i o n to r e s i st e r o s i o n . Except on s l o p e s d e f e n d e d by the Swan P e a k q u a r t z i t e s, t h e Wah Wah b e d s a r e a l w a y s r i d g e - m a k e r s and b e c a u s e of t h e ir b r o w n c o l o r m a y be m i s t a k e n f o r q u a r t z i t e f r o m a d i s t a n c e. L i t h o l o g y - The b a s e of t h e Wah Wah l i m e s t o n e c o n f o r m a b ly o v e r l i e s and i s g r a d a t i o n a l with t h e top of t h e F i l l m o r e l i m e s t o n e. The c o n t a c t was s e l e c t e d w h e r e the i n t r a f o r m a t i o n a l c o n g l o m e r a te of t h e F i l l m o r e c h a n g e s to a s e r i e s of d a r k g r a y to g r a y , m e d i u m - g r a i n e d , m e d i u m - b e d d e d s a n d y l i m e s t o n e s. T h e e n t i r e s e q u e n c e i s s a n d y with t h e p r o p o r t i o n of s a n d i n c r e a s i n g t o w a r d the t o p . Steps and s m a l l c l i f f s a r e a c h a r a c t e r i s t ic e x p r e s s i o n of t h i s l i t h o l o g y , which, f r o m a d i s t a n c e , r e s e m b l es s a n d s t o n e . The s a n d and c a l c a r e n i t e g r a n u l e s i n c r e a s e to o v e r 50 p e r c e n t of t h e t o t a l m a t e r i a l In t h e u p p e r 50 t o 60 f e e t , the e x p o s u r es w e a t h e r to f o r m s h a l l o w h o l e s in a b r o w n o u t c r o p and c a n b e e a s i ly m i s t a k e n f o r a r e l a t i v e l y p u r e s a n d s t o n e on s u p e r f i c i a l e x a m i n a t i o n. Many of t h e a r e n i t e g r a n u l e s a r e a l i g n e d e s s e n t i a l l y p a r a l l e l with the b e d d i n g while o t h e r s d i s p l a y a v e r y l o w - a n g l e , c r o s s - b e d d e d r e l a t i o n s h i p. 94 F e w i n t r a f o r m a t i o n a l c o n g l o m e r a t e b e d s a r e p r e s e n t i n t h e f o r m a t i o n . F i e l d i d e n t i f i c a t i o n - The Wah Wah f o r m a t i o n i s r e a d i l y r e c o g n i z e d by i t s b r o w n w e a t h e r i n g s a n d y s u r f a c e s . Many s m a l l b r a c h i o - p o d s and u n i d e n t i f i a b l e t r i l o b i t e s a r e p r e s e n t in t h e m o r e s i l t y b e d s. N e a r the b a s e a r e a f ew i n t r a f o r m a t i o n a l c o n g l o m e r a t e s , b u t the l a r gj p a r t of t h e s t r a t a c o n s i s t s of m e d i u m - b e d d e d , s i l t y and s a n d y b l u e - g r a y l i m e s t o n e s . The c o n f o r m a b l y o v e r l y i n g p l a t y l i m e s t o n e s of t h e J u a b f o r m a t i o n a l w a y s f o r m dip s l o p e s with t h e u p p e r m o s t b e ds of the Wah Wah in h i g h e s t r e l i e f . Some of t h e m o r e s a n d y b e ds w e a t h e r to f o r m l o n g i t u d i n a l h o l e s , a n d the r o c k a p p e a r s to b e a l i my s a n d s t o n e . Age and c o r r e l a t i o n - F a u n a was c o l l e c t e d f r o m two l o c a l i t i es ( A p p e n d i x B , P l a t e III) i n t h e Wah Wah f o r m a t i o n . R. C. B r i g ht i d e n t i f i e d the f o l l o w i n g: 0 - 6 H e s p e r o n o m i a cf. H. f o n t i n a l is M a c l u r i t e s s p. T h e Wah Wah i s of C a n a d i a n a g e. T h e Wah Wah f o r m a t i o n i s t h e a p p r o x i m a t e age e q u i v a l e n t of the u p p e r p a r t of t h e G a r d e n C i t y f o r m a t i o n in n o r t h e r n Utah and of the u p p e r half of t h e Nine M i l e f o r m a t i o n of E u r e k a , N e v a d a. 95 J u a b f o r m a t i on rMajribu&gn and t h i c k n e s s - The J u a b f o r m a t i o n c o n f o r m a b ly o v e r l i e s the Wah Wah f o r m a t i o n . The J u a b s t r i k e s n o r t h w e s t and w e s t In a b a n d about 200 f e e t wide t h r o u g h t h e c e n t r a l p o r t i o n s of t h e E a s t and West Lookout H i l l s . As with t h e H o u s e , F i l l m o r e , and Wah Wah f o r m a t i o n s , f a u l t i n g a l s o d i s p l a c e s the J u a b f o r m a t i on n o r t h w a r d . In t h e a r e a n o r t h w e s t , west, and s o u t h w e s t of B l a c k 's R a n c h In the S i m p s o n M o u n t a i n s , an o c c a s i o n a l e x p o s u r e i s s e en on t h e s l o p e s p r o t e c t e d by t h e o v e r l y i n g Swan P e a k q u a r t z i t e . Though c o v e r e d , a s m a l l a r e a n o r t h w e s t of d i n g e r ' s m i n e , in t h e h e a d of South Oak B r u s h C r e e k , i s p r e s e n t but t e r m i n a t e d to t h e west by n o r m a l f a u l t i n g which p l a c e s It in c o n t a c t with D e v o n i a n b e d s. T h e J u a b f o r m a t i o n was m e a s u r e d in t h e E a s t and West Lookout H i l l s and was 161 f e e t and 204 f e e t , r e s p e c t i v e l y. T o p o g r a p h i c e x p r e s s i o n ^ - The J u a b f o r m a t i o n w e a t h e rs r e a d i l y to f o r m s a d d l e s and c o v e r e d s l o p e s ; t h e - o v e r l y i n g K a n o sh s h a l e d e b r i s n e a r l y e v e r y w h e r e c o n c e a l s t h e J u a b . In t h e L o o k o ut H i l l s a r e a , the J u a b s t r a t a f o r m g e n t l y i n c l i n e d , n o r t h - f a c i n g dip s l o p e s s o u t h of s a d d l e s m a r k i n g the o v e r l y i n g s h a l e s. L i t h o l o g y ° The b a s a l c o n t a c t of t h e J u a b f o r m a t i o n i s g r a d a t i o n ai and i s p l a c e d w h e r e the m e d i u m - to t h i c k - b e d d e d , c o n f o r m a b l y u n d e r l y i n g b e d s of t h e Wah Wah l i m e s t o n e b e c a m e thin and s l a b b y and c o n t a in a g r e a t e r a b u n d a n c e of s i l t and s h a l y matte r i a l b e t w e e n t h e one half to 96 one i n c h t h i c k b e d s of b l u e - g r a y l i m e s t o n e . The top of t h e Wah Wah i s s a n d y , m o r e m a s s i v e , and w e a t h e r s to f o r m l e d g e s. About 100 f e e t a b o v e t h e b a s e i s a 5 - f o o t bed of c a l c a r e o us s a n d s t o n e . The b e d s of t h e m a i n b u l k of t h e f o r m a t i o n a r e t h i n - b e d d e d , s l a b b y , m e d i u m - g r a i n e d , sandy, b l u e - g r a y l i m e s t o n e s. B e d d i n g i s u n d u l a t o r y and l e n s i n g i s p r o m i n e n t. T h e J u a b g r a d e s i n t o t h e c o n f o r m a b l y o v e r l y i n g K a n o s h s h a l e, but at a l l p l a c e s t h i s zone i s m o r e o r l e s s c o v e r e d . The t o p was a r b i t r a r i l y p l a c e d b e t w e e n d e f i n i t e J u a b and d i s t i n c t K a n o s h s h a l e or a t t h e b r e a k of the s a d d l e o c c u p i e d by t h e K a n o s h s h a l e . Near the top, m a n y s i l i c i f i e d b r a c h i o p o d s w e r e c o l l e c t e d. * F i e l d i d e n t i f i c a t i o n - The J u a b f o r m a t i o n i s p o o r l y e x p o s e d, b e i n g c o v e r e d by i t s own d e b r i s and t h a t of t h e K a n o s h s h a l e . Weather i n g i s g e n e r a l l y d e e p , and only a f ew e x p o s u r e s a r e a v a i l a b l e for s t u d y . F o r the m o s t p a r t the J u a b c a n be r e c o g n i z e d by t h e a b u n d a n ce of s m a l l white b r a c h i o p o d s in a s i l t y and s l a b b y l i m e s t o n e. T h e low s l o p e b e t w e e n the K a n o s h s a d d l e s and t h e Wah Wah r i d ge s e r v e s to d e l i n e a t e t h e f o r m a t i o n. Age and c o r r e l a t i o n - T h r e e l o c a l i t i e s ( A p p e n d i x B, P l a t e III) f r o m the J u a b f o r m a t i o n y i e l d e d f o s s i l s which w e r e e x a m i n e d by R. C. B r i g h t , who r e p o r t s a s f o l l o w s: 97 0 - 3 Q r t h i s s u b a i a ta Q r t h i s s p. A n o m a l o r t h i s s p. L i n g u l a s p. O s t r a e o d s - M a c r o n o t e i l a - l i ke R e c e p t a c u i i t e s e l i i p t i e us 0 - 7 O r t h i s s u b a i a ta 0 - 1 5 Q r t h i s s u b a i a ta G a s t r o p o d s T h e p r e s e n c e of Q r t h i s s u b a i a t a i n d i c a t e s t h a t t h e J u a b f o r m a t i o n i s C h a z y a n in a g e. T h e J u a b f o r m a t i o n i s t h e a p p r o x i m a t e age e q u i v a l e n t of the u p p e r m o s t u n i t s of t h e Gar'den C i t y f o r m a t i o n in n o r t h e r n Utah, and to t h e l o w e r p o r t i o n s of t h e A n t e l o p e V a l l e y l i m e s t o n e of N o l a n , M e r r i a m , and W i l l i a m s (1956) in the v i c i n i t y of E u r e k a, N e v a d a . K a n o s h s h a le D i s t r i b u t i o n and t h i c k n e s s - The K a n o s h s h a l e i s v e r y p o o r ly e x p o s e d b e i n g h i d d e n b e n e a t h e i t h e r s o i l o r f l o a t f r o m the o v e r l y i ng Swan P e a k q u a r t z i t e . No c o m p l e t e e x p o s u r e was found in the S h e e p r o c k o r S i m p s o n M o u n t a i n s . This s h a l e i s p r e s e n t in i ts e n t i r e t y in t h e E a s t and W e s t L o o k o u t H i l l s a s a n a r r o w b a n d d i p p i ng b e n e a t h t h e c l i f f - f o r m i n g Swan P e a k q u a r t z i t e. 98 A t o t a l of 205 f e e t of t h e s h a l e was m e a s u r e d in t h e E a s t Lookout H i l l s a r e a , but t h i s m a y be in c o n s i d e r a b l e e r r o r b e c a u s e n e i t h er t h e top nor b o t t o m i s e x p o s e d . The K a n o s h s h a l e m a y be up to 400 f e e t t h i c k in t h e S i m p s o n M o u n t a i n s , bui^ b e i n g o b s c u r e d , it was not m e a s u r e d . T o p o g r a p h i c e x p r e s s i o n - The K a n o s h s h a l e w e a t h e r s r e a d i l y to f o r m s a d d l e s and s l o p e s and i s n e v e r found in p o s i t i v e r e l i e f. L i t h o l o g y - The b a s e of t h e K a n o s h s h a l e a p p e a r s to be g r a d a t i o n al with and c o n f o r m a b l y above the J u a b l i m e s t o n e . The p l a t y l i m e s of t h e J u a b g r a d u a l l y b e c o m e m o r e and m o r e s h a l y , but t h e b a s e of t he K a n o s h i s e v e r y w h e r e c o v e r e d . The d i p s l o p e o r b r e a k of t h e s a d d le b e t w e e n t h e J u a b and Swan P e a k q u a r t z i t e s a f f o r d s a m e a n s f o r d e t e r m i n i n g t h e c o n t a c t. E x c e p t n e a r i g n e o u s i n t r u s i o n s or e x t r u s i o n s , the K a n o s h i s a v e r y f i s s i l e s h a l e and i s u s u a l l y c o v e r e d by a t h i c k b l a n k e t of s o i l. O l i v e d r a b , m a r o o n , g r a y i s h - g r e e n , and b l a c k a r e t h e c h a r a c t e r i s t ic c o l o r s of t h e s h a l e . One c o l o r p r e d o m i n a t e s at any one l o c a l i t y and t h e u n i t c a n n o t be c o n s i d e r e d a s v a r i e g a t e d . T r i i o b i t e s , b r a c h i o p o d s, and g r a p t o l i t e s a r e p r e s e n t. T h e top of t h e s h a l e I s c h a r a c t e r i z e d by u n d u l a t o r y , thin, p l a t y, l e n s i n g l i m e s t o n e s which a r e e x t r e m e l y f o s s i l l f e r o u s , b e a r i ng b r a c h i o p o d s , t r i i o b i t e s , and R e c e p t a c u l i t e s . The t h i n s h a l e - l i me s e q u e n c e g i v e s way to t h e s h a l e - q u a r t z i t e s t r a t a which m a r k t h e top 99 of t h e K a n o s h and t h e b o t t om of t h e Swan P e a k q u a r t z i t e. F i e l d i d e n t i f i c a t i o n - The K a n o s h s h a l e i s v e r y f i s s i l e and m a y b e b l a c k , m a r o o n , or g r e e n in c o l o r . It c a n b e m i s t a k en l i t h o l o g i c a l l y f o r o t h e r s h a l e s r a n g i n g f r o m M i s s i s s i p p i a n to P r e c a m b r i a n , but t h e g r a p t o l i t e s which a r e found i n a l l e x p o s u r es a r e d i a g n o s t i c. Age and c o r r e l a t i o n - R. C. B r i g h t e x a m i n e d c o l l e c t i o n s f r om t h r e e l o c a l i t i e s (Appendix B, P l a t e III) in t h e K a n o s h s h a l e and r e p o r t s : 0 - 1 4 D i d y m o g r a p t u s cf. D. a r t us 0 - 1 6 T r i i o b i t e f r a g m e n ts A n o m a l o r t h i s s p. O r t h o c o n e c e p h a l o p od R e c e p t a c u i i t e s s p. 0 - 2 2 E l e u t h e r o c e n t r u s p e t e r s o ni G o n i o t e l u s s p. L i n g u i e l l a s p. Linguist s p. G a s t r o p o d s O s t r a c o d s D i d y m o g r a p t u s a r t us P r o t o c y c j : o c e r a s s p. O r t h o c o n e t y p es M o d i o l o p s i s s p. The f a u n a c o r r e s p o n d s to t h e M z o n e of H i n t z e ( 1 9 5 1 , p . 18-19) of t h e l o w e r K a n o s h s h a l e. 100 T h e K a n o s h s h a l e i s t h e a p p r o x i m a t e age e q u i v a l e n t of the l o w e r p a r t of t h e Swan P e a k f o r m a t i o n of R o s s (1949) In n o r t h e a s t e rn Utah; the u p p e r half of t h e A n t e l o p e V a l l e y l i m e s t o n e of E u r e k a, N e v a d a ; and t h e O r i e n t s h a l e m e m b e r of t h e O r i e n t f o r m a t i o n in t h e West T i n t i c m i n i n g d i s t r i c t on t h e e a s t e r n edge of t h e S h e e p r o ck R a n g e ( S t r i n g h a m , 1942, p . 271). It i s p r o p o s e d t h a t the n a m es O r i e n t f o r m a t i o n and i t s s u b d i v i s i o n s O r i e n t s h a l e and O r i e nt q u a r t z i t e be s u p p l a n t e d by t h e K a n o s h s h a l e and t h e Swan P e ak q u a r t z i t e . The b e d s above the O r i e n t q u a r t z i t e h a v e b e e n r e c o g n i z e d by G a r d n e r (1952) to b e u n i t s of the F i s h H a v e n d o l o m i t e. Swan P e a k q u a r t z i te D i s t r i b u t i o n and t h i c k n e s s - The Swan P e a k q u a r t z i t e i s c o n s i d e r e d to b e t h e b e s t m a r k e r bed i n t h e S h e e p r o c k M o u n t a i n s . It c r o s s e s the E a s t and West L o o k o u t H i l l s in a 3 0 0 - f o o t b a n d in a n o r t h w e s t e r l y d i r e c t i o n and i s o f f s e t to t h e n o r t h in t h e w e s t e rn f o o t h i l l s . The q u a r t z i t e i s well e x p o s e d a s a s e r i e s of j u m b l ed b l o c k s e x t e n d i n g f r o m the n o r t h w e s t e r n m o s t e x p o s u r e of t h e S h e e p r o c k g r a n i t e w e s t w a r d a c r o s s E r i c k s o n ' s P a s s to t h e h i g h n o r t h - s o u t h d i v i d e of t h e c e n t r a l p a r t of t h e S i m p s o n M o u n t a i n s. The Swan P e a k m e a s u r e s 462 f e e t in t h e E a s t Lookout H i l ls but i s s l i g h t l y t h i n n e r in the S i m p s o n M o u n t a i n s . No d e t e c t a b le t h i n n i n g was n o t e d in the L o o k o u t H i l l s a r e a. 101 T o p o g r a p h i c e x p r e s s i o n - The Swan P e a k a l w a y s w e a t h e rs to f o r m p r o m i n e n t r i d g e s and c l i f f s . The soft, u n d e r l y i n g K a n o sh s h a l e s e r v e s to e m p h a s i z e the Swan P e a k. F i e l d i d e n t i f i c a t i o n - The Swan P e a k q u a r t z i t e i s m e d i u m - g r a i n e d , r a n g e s f r o m white to t a n with a f ew g r a y b e d s n e a r the b a s e , and in p l a c e s s h o w s c r o s s - b e d d i n g . The t a l u s b l o c ks f r o m m a n y of t h e b e d s w e a t h e r e a s i l y to f o r m r o u n d e d c o r n e r s; s o m e of t h e s t r a t a a r e m o r e n e a r l y s a n d s t o n e t h a n q u a r t z i t e . Near t h e b a s e of t h e u n i t i s a v e r y t h i n s e r i e s of g r a y and buff q u a r t z i t es c o n t a i n i n g an a b u n d a n c e of p h o s p h a t i c s h a r d s and d e b r i s . Close e x a m i n a t i o n r e v e a l s m a n y c u r v e d s l i v e r - l i k e p l a t e s of a b l a ck m a t e r i a l a s t h i n , g e n e r a l l y p a r a l l e l s t r e a k s . T h e s e f r a g m e n ts w e a t h e r to l i g h t b l u i s h - g r a y . Included in t h e s a m e s e r i e s a re m a n y f u c o i d a l q u a r t z i t e s and a f ew t a n , m i c a c e o u s s h a l e s . E v e r y w h e r e the top of t h e q u a r t z i t e s i s in s h a r p c o n t a c t with the d a r k, c h e r t y F i s h H a v e n d o l o m i t e s . About 40 f e e t f r o m the b o t t o m i s a 6 - f o o t bed of q u a r t z i t e t h a t w e a t h e r s with a s w i s s c h e e s e t e x t u r e. T h o u g h not u n i v e r s a l l y p r e s e n t , t h i s l i t h o l o g y s e r v e s a s an a id t o i d e n t i f i c a t i o n . The Swan P e a k c a n b e m i s t a k e n f o r the T i n t ic o r a P r e c a m b r i a n q u a r t z i t e if only a l i m i t e d e x p o s u r e i s s e e n. L i t h o l o g y - The b a s e of t h e q u a r t z i t e i s c o v e r e d in m o s t of the o u t c r o p a r e a . However, in t h e e a s t w a r d - t r e n d i n g gulch, s o u t h w e st f r o m the e a s t e r n m o s t e x p o s u r e of t h e Swan P e a k q u a r t z i t e in the 102 West L o o k o u t H i l l s , p o r t i o n s of t h e b a s e with i t s f u c o i d a l c o n o d o n t - b e a r l n g b e d a r e e x p o s e d in t h e d r a i n a g e b o t t o m . The b a s a l 60 to 80 f e e t of t h e f o r m a t i o n a r e f u c o i d a l and c o n s i s t m a i n l y of r e d d i sh and g r e e n i s h t i n t e d q u a r t z i t e s with a f ew b e d s b e t w e e n two and e i g h t I n c h e s of g r e e n m i c a c e o u s s h a l es T h e " p h o s p h a t i c key b e d " w e a t h e r s to r e s e m b l e b l e a c h e d b o n e. P e r h a p s a b e t t e r n a m e would be " c o n o d o n t b e d " , but t h i s would i m p ly t h a t c o n o d o n t s a r e p r e s e n t only i n t h i s h o r i z o n which m a y not be the c a s e , as f u t u r e p a l e o n t o l o g i c i n v e s t i g a t i o n s m a y p r o v e . The " p h o s p h a t i c key b e d " i s v e r y e v i d e n t w h e r e v e r the b a s a l Swan P e ak was found; a l t h o u g h s e l d o m s e e n in o u t c r o p , t h e t a l u s o v e r l y i n g the K a n o s h s h a l e h a s y i e l d e d f l o a t of the p h o s p h a t i c b e d . The " p h o s p h a t ic k e y b e d " i s a d a r k b r o w n to r e d q u a r t z i t e which s o m e g e o l o g i s t s m ay c a l l a g r a y w a e k e - l i k e r o c k . Bedding p l a n e s a r e u s u a l l y f u c o i d al c o n t a i n i n g light p a s t e l g r e e n , m i n u t e l y m i c a c e o u s s h a l e s b e t w e en t h e f u c o i d s . F r a g m e n t s of p h o s p h a t i c s h e l l m a t e r i a l a r e p r e s e nt i n t h i n l a y e r s and a s r a n d o m l y s c a t t e r e d p a r t i c l e s in t h e q u a r t z i t e s. T h e s e f r a g m e n t s a r e s m a l l , s l i g h t l y c u r v e d in s e c t i o n , and a re u s u a l l y a n g u l a r , showing n o g r e a t a m o u n t of w e a r i n g and p r o b a b ly i n d i c a t e l i m i t e d t r a n s p o r t a t i o n ; t h e y a r e p r o b a b l y t r i i o b i t e and b r a c h i o p o d r e m a i n s . O c c a s i o n a l l y a c o n o d o n t will be found in t h i s m a t e r i a l . The s h a r d s w e a t h e r to a g r a y - w h i t e s u r f a c e and g i ve p o r t i o n s of t h e r o c k a l i g h t g r a y c a s t , like b l e a c h e d b o n e. 103 T h e m a i n m a s s of t h e Swan P e a k q u a r t z i t e i s a well s o r t e d, well r o u n d e d , p u r e q u a r t z i t e . C r o s s - b e d d i n g was n o t e d but is g e n e r a l l y a b s e n t . Most e x p o s u r e s of t h e Swan P e a k a r e white to •old i v o r y * c o l o r e d o r t h o q u a r t z i t e s ; h o w e v e r , in s o m e p l a c es p o c k e t s of u n c e m e n t e d s a n d s w e a t h e r to f o r m h o l e s g i v i n g the o u t c r o p a s w i s s c h e e s e a p p e a r a n c e ( P l a t e XIX). Also s o m e of t h e p o o r l y c e m e n t e d r o c k s b e c o m e r o u n d e d , like e x f o l i a t e d g r a n i t e. Age and c o r r e l a t i o n - One l o c a l i t y in t h e t h i n t r a n s i t i o n al z o n e b e t w e e n t h e K a n o s h s h a l e and t h e Swan P e a k q u a r t z i t e y i e l d ed t h e f o l l o w i n g f o s s i l s which w e r e i d e n t i f i e d by R. C. B r i g h t: 0 - 1 7 C o n o d o n t s Q i s t o d u s s p . n e w f o r ms S t e r e o c o n u s s p . n e w f o r ms P l a t e - l i k e s t r u c t u r es F u c o i d s T h e Swan P e a k q u a r t z i t e i s M i d d l e O r d o v i c i a n in a g e. T h e Swan P e a k q u a r t z i t e i s t h e a p p r o x i m a t e age e q u i v a l e n t to p a r t s of t h e Swan P e a k q u a r t z i t e and t h e E u r e k a q u a r t z i t e of Webb (1956) in t h e I b e x H i l l s a r e a , Utah; t h e m a s s i v e q u a r t z i t e u n i t s of t h e Swan P e a k f o r m a t i o n s of R i c h a r d s o n (1913) i n n o r t h e a s t e r n Utah; a n d t h e O r i e n t q u a r t z i t e of t h e West T i n t i c d i s t r i c t , Utah. F i s h H a v e n d o l o m i te G e n e r a l - N e a r l y e v e r y w h e r e in t h e G r e a t B a s i n p r o v i n c e, w h e r e t h e Swan P e a k or E u r e k a q u a r t z i t e i s found, the F i s h Haven View of the Swan Peak quartzite in the East Lookout Hills. Note holes which represent poorly cemented parts of rock. 104 o r a s i m i l a r d a r k c o l o r e d d o l o m i t e i s p r e s e n t o v e r l y i n g the q u a r t z i t e * G e n e r a l l y the q u a r t z i t e - d o l o m i t e c o n t a c t will foe l o c a l ly c o n f o r m a b l e , but i n a f ew p l a c e s a s l i g h t d i s c o r d a n c e h a s b e en n o t e d . V a r i o u s i n v e s t i g a t i o n s h a v e d e m o n s t r a t e d t h e e x i s t e n ce of a h i a t u s at t h e t o p of M i d d l e O r d o v i c i a n which e x t e n d s to b e y o nd t h e m i d d l e of l a t e O r d o v i c i a n t i m e . This i n t e r v a l would s e e m to i n d i c a t e a p e r i o d of l i t t l e o r no e r o s i o n o r d e p o s i t i o n , b e c a u s e it i s a p p a r e n t l y e v e r y w h e r e p r e s e n t in t h e w e s t e r n s t a t e s. I t i s p o s s i b l e t h a t e r o s i o n was a f f e c t i n g a s u r f a c e of e x t r e m e ly l ow r e l i e f a s e v i d e n c e d by t h e p r e s e n c e of t h e a l m o s t c o n t i n u o us b l a n k e t of q u a r t z i t e , which to h a v e s u r v i v e d t h i s e x t e n d e d p e r i od of t i m e , m u s t h a v e b e e n r e l a t i v e l y u n t o u c h e d . This quiescefeit p e r i o d m u s t h a v e b e e n a f f e c t i n g a t e r r a n e which not o n l y was p o s i t i v e but m u s t h a v e b e e n of e x t r e m e l y l ow r e l i e f. T h e a d v a n c e of t h e F i s h H a v e n s e a m u s t h a v e b e e n r a p i d , at l e a s t f a s t enough to i n h i b i t t h e f o r m a t i o n of a n o r m a l s h a l e s e q u e n ce b e l o w t h e c a r b o n a t e b e d s. D i s t r i b u t i o n and t h i c k n e s s - The F i s h H a v e n d o l o m i t e is t h e m o s t w i d e s p r e a d of t h e P a l e o z o i c f o r m a t i o n s in t h e S h e e p r o ck a r e a ; s m a l l p a t c h e s a r e found in t h e Desfert M o u n t a i n s and m a ny b l o c k s a r e p r e s e n t in a t r e n d w e s t f r o m t h e S h e e p r o c k g r a n i te a c r o s s E r i c k s o n ' s P a s s and i n t o t h e higti r i d g e s of t h e S i m p s on M o u n t a i n s . The E a s t and W e s t L o o k o u t H i l l s p r o v i d e the b e st 105 e x p o s u r e s . The d a r k b l u e - g r a y d o l o m i t e s c h a r a c t e r i s t i c of the u n i t c r o p out in an 8 0 0 - f o o t b a n d e x t e n d i n g f r o m the s o u t h e a s t to t h e n o r t h w e s t at a l o c a t i o n s l i g h t l y n o r t h of t h e c e n t e r of t h e h i l l s. B r o w n ' s R i d g e , in t h e W e s t T i n t i c M o u n t a i n s , c o n s i s t s m a i n l y of F i s h H a v e n d o l o m i t e. I n t h e c e n t r a l p a r t of t h e E a s t L o o k o u t H i l l s t h e F i s h H a v e n is 706 f e e t t h i c k . The F i s h H a v e n d o l o m i t e , as m e a s u r e d by G a r d n er ( 1 9 5 4 , p . 1 7 - 1 8 ) , i s 1,280 f e e t t h i c k in t h e W e s t T i n t i c m i n i ng d i s t r i c t . The t h i c k n e s s d o e s not a p p e a r to c h a n g e in t h e S i m p s on M o u n t a i n s and i s b e t w e e n 500 a n d 700 f e e t thick* as in E a s t L o o k o u t Hills T o p o g r a p h i c e x p r e s s i o n - The F i s h Haven d o l o m i t e w e a t h e rs t o f o r m r i d g e s and c l i f f s . In s t e e p l y d i p p i n g r o c k s e q u e n c e s a s h a rp s a d d l e i s u s u a l l y found b e t w e e n t h e F i s h Haven and t h e u n d e r l y i ng q u a r t z i t e s ; the top of the F i s h Haven f o r m s dip s l o p e s . Many c l i f fs c o n t a i n s h a l l o w c a v e s at t h e b a s e which g e n e r a l l y m a r k the top of t h e m o r e s l a b b y b a s a l b e d s. L i t h o l o g y - The b a s e of t h e f o r m a t i o n a p p e a r s to b e c o n f o r m a b le on t h e Swan P e a k q u a r t z i t e ; a d i s c o n f o r m i t y i s p r o b a b l y p r e s e n t at t h i s p o i n t a s t h e r e g r e s s i v e Swan P e a k q u a r t z i t e would s e e m to i n d i c a t e . P a r a l l e l i s m b e t w e e n t h e b e d s of t h e Swan P e a k q u a r t z i te a n d t h e F i s h H a v e n d o l o m i t e i s e v e r y w h e r e p r e s e n t ; the b a s a l unit i s 128 f e e t t h i c k a n d i s c o m p o s e d p r i m a r i l y of d a r k g r a y , c h e r t y, m e d i u m - g r a i n e d , c r y s t a l l i n e d o l o m i t e , in b e d s 4 t o 8 i n c h e s t h i c k. 106 Many of t h e t a n and b l a c k c h e r t s a r e in b a n d s f r o m 1 t o 3 i n c h es t h i c k ; o t h e r s a r e a s e l o n g a t e n o d u l e s ; t h e s e c h e r t s w e a t h e r r e d d i s h - b r o w n . The b a s a l u n i t w e a t h e r s m o r e e a s i l y and f o r m s s a d d l es b e t w e e n the m o r e r e s i s t a n t u n d e r l y i n g Swan P e a k q u a r t z i t e and the o v e r l y i n g m a s s i v e d o l o m i t e s c o m p r i s i n g the b u l k of t h e F i sh Haven d o l o m i t e . T h e g r e a t e r p o r t i o n of t h e F i s h H a v e n c o n s i s t s of d a r k g r a y, m e d i u m - g r a i n , m e d i u m - b e d d e d to m a s s i v e d o l o m i t e s . This p a rt i s a c l i f f - f o r m i n g s e q u e n c e and c o m p r i s e s about 484 f e e t of s t r a t a. The c h e r t b o x w o r k z o n e s c h a n g e a l o n g s t r i k e , in p l a c e s b e c o m i ng e n t i r e l y m a s s i v e c h e r t ; t h e s e z o n e s p r o b a b l y do not p e r s i s t a s a r e l i a b l e m a p p a b l e u n i t , e x c e p t in a g e n e r a l way. Most of the d o l o m i t e b e d s of t h e F i s h H a v e n w e a t h e r with a s u r f a c e t e x t u re s i m i l a r to m e d i u m to c o a r s e s a n d p a p e r. F i e l d i d e n t i f i c a t i o n - The F i s h Haven i s e a s y to r e c o g n i z e if a f a i r l y l a r g e e x p o s u r e i s e x a m i n e d . The c h a i n c o r a l ( H a l y s i t e s) was found in e v e r y o u t c r o p , but i n m o s t i n s t a n c e s a d i l i g e n t s e a r ch was r e q u i r e d , e s p e c i a l l y in t h e m o r e c h e r t y z o n e s . The f i r st a p p e a r a n c e of c r i n o i d c o l u m n a l s with a f i v e - p o i n t e d c e n t r a l c a n al i s in t h e l o w e r b e d s of t h e F i s h H a v e n d o l o m i t e . Near the top of t h e s e q u e n c e m u c h d a r k g r a y to b l a c k c h e r t , as b e d s , n o d u l e s, a n d a s b o x w o r k f r a c t u r e f i l l i n g , i s p r e s e n t ; s o m e of t h e c h e r t o c c u rs a s p a l e p i n k i s h - g r a y o n i o n - l i k e m a s s e s . E x c e p t f o r the b a s a l b e d s, 107 t h e F i s h Haven w e a t h e r s v e r y r o u g h and t e n d s to f o r m s h a l l ow c a v e s . The light g r a y , f i n e - g r a i n e d L a k e t o w n ( ? ) d o l o m i t e c o n f o r m a b l y o v e r l i e s t h e d a r k d o l o m i t e s of t h e F i s h H a v e n . The c o l or c h a n g e and t h e p r e s e n c e of t h e b e d d e d c h e r t s s e r v e to e s t a b l i s h the c o n t a c t . Age and c o r r e l a t i o n - F o s s i l s w e r e c o l l e c t e d f r o m n i n e l o c a l i t i es i n t h e F i s h Haven d o l o m i t e ( A p p e n d i x B, P l a t e I I I ) , but a l l w e r e v e ry p o o r l y p r e s e r v e d . The f o l l o w i n g f o r m s w e r e i d e n t i f i e d by t h e w r i t e r: H a l y s i t e s cf. 1L c a t e n u l a r ia S y r i n g o p o r a s p. S t r e p t e l a s m a s p. C r i n o i d c o l u m n a ls B r a c h i o p o d f r a g m e n ts T h e F i s h H a v e n d o l o m i t e c o r r e l a t e s l i t h o l o g i c a l l y with d o l o m i t es o v e r l y i n g the M i d d l e O r d o v i c i a n q u a r t z i t e s at n u m e r o u s l o c a l i t i e s in t h e G r e a t B a s i n . The f a u n a found in t h e S h e e p r o c k s e c t i o n i s not s u f f i c i e n t l y d i a g n o s t i c to g i v e an e x a c t a g e . However, the l i t h o l o gy a n d s t r a t i g r a p h i c p o s i t i o n of t h e d o l o m i t e l e a v e l i t t l e doubt t h a t it i s the F i s h Haven and i s of R i c h m o n d ( L a t e O r o d o v i c i a n ) a g e. T h e F i s h Haven c o r r e l a t e s with t h e H a n s o n C r e e k f o r m a t i o n of M e r r i a m (1940) in R o b e r t s C r e e k M o u n t a i n , Nevada; the E l y S p r i n gs f o r m a t i o n of W e s t g a t e and Knopf (1932) of t h e P i o c h e d i s t r i c t, N e v a d a ; the l o w e r p a r t of t h e B l u e B e l l d o l o m i t e of L o u g h l i n (1919) in t h e T i n t i c d i s t r i c t , Utah. The B l u e B e l l h a s b e e n s u b d i v i d e d by L o v e r i n g and o t h e r s (1949) and t h e F i s h Haven p o r t i o n d e s i g n a t ed 108 t h e E a g l e d o l o m i t e . Mr. H. T. M o r r i s of t h e U. S. G e o l o g i c al S u r v e y , by o r a l c o m m u n i c a t i o n with the w r i t e r , v e r i f i e s the e x i s t e n c e of t h e F i s h Haven d o l o m i t e at T i n t i c. O r d o v i c i a n - S i l u r i a n b o u n d a ry T h e O r d o v i c i a n - S i l u r i a n b o u n d a r y w i t h i n t h e C o r d i i l e r a n r e g i on i s v e r y p r o b l e m a t i c a l and I n d e f i n i t e . Most w o r k e r s s e p a r a t e the F i s h Haven d o l o m i t e f r o m the L a k e t o w n d o l o m i t e on t h e b a s i s of f a u n a a n d / o r l i t h o l o g y . If f o s s i l s a r e p r e s e n t , the P e n t a m e r c is b r a c h i o p o d s e r v e s a s a g u i d e f o r the S i l u r i a n . I n v e s t i g a t i o r u s u a l ly c h o o s e the n e x t l o w e r l i t h i c u n i t b e l o w the p e n t a m e r o i d - b e a r i ng s t r a t a a s the t o p of t h e O r d o v i c i a n . If d i a g n o s t i c f o s s i l s a r e a b s e n t, a c o l o r o r t e x t u r a l c h a n g e m a y s e r v e a s t h e d e m a r k a t i o n . In s o me a r e a s a c o l o r o r t e x t u r a l c h a n g e , though p r e s e n t , may a m o u n t to o n l y a f ew f e e t of s t r a t a . G e n e r a l l y , w o r k e r s who d i f f e r e n t i a te t h e O r d o v i c i a n f r o m the S i l u r i a n e n t i r e l y by l i t h o l o g y will h a ve t h i c k e r S i l u r i a n s e c t i o n s t h a n t h o s e of n e a r b y a r e a s , w h e r e a d i a g n o s t ic f a u n a i s found. R i c h a r d s o n ( 1 9 4 1 , p . 1 7 - 1 8 ) in d e s c r i b i n g the t y p e F i s h Haven d i s t i n g u i s h e s t h e O r d o v i c i a n f r o m the S i l u r i a n on t h e b a s i s of c o l o r; t h e L a k e t o w n b e i n g a light g r a y to white d o l o m i t e , while t h e F i sh H a v e n i s d a r k g r a y to b l u e - b l a c k d o l o m i t e. In t h e Gold H i l l a r e a , Nolan ( 1 9 3 5 , p . 16-17) s e p a r a t e s the F i s h Haven d o l o m i t e f r o m the L a k e t o w n on t h e b a s i s of S i l u r i a n f a u na 1 09 a n d t h e p r e s e n c e of d o l o m i t e c o n g l o m e r a t e s and d o l o m i t e s a n ds i n t h e b a s a l L a k e t o w n , a n d s t a t e s: . . the d o l o m i t e c o n g l o m e r a t e and wavy c o n t a c t found at t h e b a s e of t h e L a k e t o wn a r e no b e t t e r d e f i n e d t h a n s i m i l a r f e a t u r es w i t h i n m a n y of t h e l o w e r P a l e o z o i c f o r m a t i o n s . 1 1 A c o l o r c h a n g e i s n o t p r e s e n t i n t h e Gold H i l l a r e a , and e x c e pt f o r t h e a f o r e m e n t i o n e d f e a t u r e s , the f o r m a t i o n s b l e n d with e a ch o t h e r . The w r i t e r s p e n t o n e d a y in t h e I b a p a h a r e a n e a r t h e m o u th of Sevy C a n y o n and n o t e d t h a t t h e L a k e t o w n was d a r k b l u e - g r a y and c o n t a i n e d s c a t t e r e d c h e r t a b o u t 35 t o 400 f e e t b e l o w t h e t o p . This c h e r t y z o n e y i e l d e d a b u n d a n t f o s s i l s , i n c l u d i n g F a v o s i t e s , H a l y s i t e s, p e n t a m e r o i d . and o t h e r b r a c h i o p o d s , cup c o r a l s , and o t h e r c o r al d e b r i s . I n c e n t r a l U t a h , B a u e r ( 1 9 5 2 ) , m a p p i n g i n t h e T h o m a s R a n g e, s e p a r a t e s t h e F i s h H a v e n f r o m t h e L a k e t o w n on t h e b a s i s of p e n t a m e r o i d b r a c h i o p o d s . At t h i s l o c a l i t y t h e F i s h H a v e n i s light to m e d i u m g r a y , w h e r e a s t h e o v e r l y i n g L a k e t o w n i s a w h i t e c r y s t a l l i ne d o l o m i t e . M o r r i s ( p e r s o n a l c o m m u n i c a t i o n , 1956) i n a d e t a i l e d s t u d y of t h e E a s t T i n t i c a r e a , p l a c e s t h e O r d o v i c i a n - S i l u r i a n b o u n d a r y in a c h e r t y z o n e , f a u n a of e a c h p e r i o d b e i n g p r o c u r e d w i t h i n 20 f e e t of the, c h e r t . The c h e r t i s d i s t r i b u t e d i n . s u c h a way a s t o g i v e the u n i t a " l e o p a r d s k i n " a p p e a r a n c e. 110 In t h e W e s t T i n t i c m i n i n g d i s t r i c t at the s o u t h e a s t end of t h e S h e e p r o c k M o u n t a i n s , G a r d n e r (1954, p. 13) a r b i t r a r i l y d i s t i n g u i s h e d F i s h Haven f r o m L a k e t o w n by m e a n s of a c h e r t z o n e. He f u r t h e r s t a t e s , " T h e u s u a l l y l a r g e t h i c k n e s s of 1, 280 f e e t is u n d o u b t e d l y due to i n c l u s i o n of p a r t of the o v e r l y i n g L a k e t o w n d o l o m i te i n t h e u n i t ." H a n s o n (1949), w o r k i n g i n t h e s o u t h e r n M a i a d R a n g e in n o r t h e rn U t a h , s t a t e s : The F i s h Haven d o l o m i t e " . . . i s d i s t i n g u i s h a b le f r o m the o v e r l y i n g L a k e t o w n d o l o m i t e only on t h e b a s i s of i ts d a r k e r c o l o r ". Young ( 1 9 5 5 , p . 23) a d m i t s t h a t t h e L a k e t o w n i s d i f f i c u l t to s e p a r a t e f r o m the u n d e r l y i n g F i s h H a v e n d o l o m i t e and s u b d i v i d es t h e two on t h e p r e s e n c e of p e n t a m e r o i d b r a c h i o p o d s and v u gs l i n e d with q u a r t z c r y s t a l s. W i l l i a m s (1948, p. 1,137) c l e a r l y d i s t i n g u i s h e s the O r d o v i c i a n f r o m the S i l u r i a n by l i t h o l o g y and f a u n a in t h e L o g an q u a d r a n g l e . The F i s h H a v e n i s d a r k n e u t r a l g r a y in c o n t r a s t with t h e l i g ht g r a y b a s a l L a k e t o w n s t r a t a. T h e L a k e t o w n d o l o m i t e v a r i e s in l i t h o l o g y f r o m p l a c e to p l a ce but c a n g e n e r a l l y be d i v i d e d i n t o two f a d e s . One with l i g h t g r ay l i t h o l o g y p r e d o m i n a t i n g i s at and a r o u n d t h e t y p e s e c t i o n in n o r t h e rn U t a h , and t h e o t h e r m o r e s o u t h e r n s e c t i o n s , w h e r e d a r k g r a y and b l a c k s t r a t a c o m p r i s e n e a r l y the e n t i r e S i l u r i a n s y s t e m . In the I l l n o r t h e r n S h e e p r o c k a r e a t h e S i l u r i a n i s d i f f i c u l t to s e p a r a t e f r o m the O r d o v i c i a n and a s in m o s t o t h e r p l a c e s was d i s t i n g u i s h e d by the p r e s e n c e of t h e p e n t a m e r o i d b r a c h i o p o d s above a " l e o p a r d s k i n" c h e r t z o n e , s i m i l a r to t h a t at T i n t i c . No m a r k e d c o l o r c h a n g e was n o t e d , and t h e l o w e r p a r t of t h e L a k e t o w n i s a s d a r k a g r a y a s the u n d e r l y i n g F i s h H a v e n d o l o m i t e . Stokes ( p e r s o n a l c o m m u n i c a t i o n, 1956) u s e s t h e q u a r t z c r y s t a l l i n e d v u g s a s a c r i t e r i a f o r L a k e t o wn l i t h o l o g y In n o r t h e r n Utah. 112 SILURIAN SYSTEM G e n e r a l s t a t e m e nt T h e S i l u r i a n s y s t e m i s p o o r l y r e p r e s e n t e d in t h e S h e e p r o c k - S i m p s o n M o u n t a i n r e g i o n . Beds a s s i g n e d to the S i l u r i a n h a v e few-f o s s i l s and c a n n o t be p o s i t i v e l y c o r r e l a t e d . S t r a t a t o t a l l i n g 1,001 f e e t h a v e t e n t a t i v e l y b e e n a s s i g n e d to t h e S i l u r i a n . The L a k e t o wn d o l o m i t e i s t h e only S i l u r i a n f o r m a t i o n r e c o g n i z e d in t h e a r e a. L a k e t o w n d o l o m i te D i s t r i b u t i o n and t h i c k n e s s ° The S i l u r i a n r o c k s c r o p out in n u m e r o u s p l a c e s in t h e S h e e p r o c k - S i m p s o n r e g i o n . The m o st e x t e n s i v e e x p o s u r e i s a n e a r l y c o n t i n u o u s b a n d about 1, 200 f e et wide in t h e E a s t and the West L o o k o u t H i l l s a r e a . S i l u r i a n s t r a t a a re p r e s e n t n e a r the g r a n i t e c o n t a c t in E l d e r b e r r y Canyon, n o r t h of d i n g e r ' s m i n e , and a l s o a p p r o x i m a t e l y t h r e e q u a r t e r s of a m i le w e s t of t h e m i n e d u m p . Another e x p o s u r e in the S i m p s o n M o u n t a i ns i s a p p r o x i m a t e l y one m i l e w e s t of t h e s u m m i t of E r i c k s o n ' s P a s s . S i n c e t h e u p p e r and l o w e r c o n t a c t s of t h e S i l u r i a n a r e i n d e f i n i t e, t h e t h i c k n e s s of 1, 001 f e e t i s o n l y an a p p r o x i m a t i o n and i s b a s ed m o s t l y on a s l i g h t l i t h o i o g i c c h a n g e at t h e b a s e , and t h e p r e s e n ce of s c a t t e r e d q u a r t z sand g r a i n s in t h e l i g h t g r a y d o l o m i t e s at t h e t o p. No t h i n n i n g was d e t e c t e d in the L a k e t o w n d o l o m i t e ; h o w e v e r, G a r d n e r (1954, p . 18) m e a s u r e d 945 f e e t of the f o r m a t i o n in the 113 s o u t h e r n p a r t of t h e S h e e p r o c k m o u n t a i n s. T o p o g r a p h i c e x p r e s s i o n - The S i l u r i a n b e d s w e a t h e r m o re e a s i l y t h a n t h e u n d e r l y i n g d a r k , c h e r t y , m o r e c r y s t a l l i n e d o l o m i t es of t h e F i s h Haven and f o r m s l i g h t s a d d l e - l i k e d e p r e s s i o n s . The a p p a r e n t l y c o n f o r m a b l y o v e r l y i n g D e v o n i a n r o c k s a r e s l i g h t l y m o re r e s i s t a n t t h a n the S i l u r i a n and n e a r l y a l w a y s r i s e g e n t l y f r o m the s a d d l e s f o r m e d by the L a k e t o w n d o l o m i t e. L i t h o l o g y - The L a k e t o w n d o l o m i t e i s not a d i s t i n c t unit; t h e l o w e r half c a n be e a s i l y m i s t a k e n f o r the F i s h H a v e n , w h e r e as t h e u p p e r half r e s e m b l e s D e v o n i a n s t r a t a . The l o w e r p o r t i o n c o n s i s ts m a i n l y of d a r k g r a y , m e d i u m - g r a i n e d , c r y s t a l l i n e , c h e r t y d o l o m i t e. D o l o m i t i z a t i o n h a s , e x c e p t f o r v a g u e o u t l i n e s , d e s t r o y e d the f o s s i ls which i n s o m e z o n e s a r e r a t h e r p r o l i f i c . Bedding i s f r o m 3 to 8 i n c h e s a p a r t with s o m e z o n e s b e i n g p o o r l y l a m i n a t e d . C h e r t is c o m m o n to a b u n d a n t , and s o m e s t r a t a c o n t a i n up t o 80 p e r c e nt s i l i c a . H a l y s i t e s , S y r i n g o p o r a , C a i o p a e c i a , and s m a l l c u p c o r a l s , a l o n g with s t r o m o t o p o r i d s and p e n t a m e r o i d b r a c h i o p o d s , a r e found i n t h e l o w e r half of t h e f o r m a t i o n . The u p p e r half i s d o m i n a n t ly g r a y , a p h a n i t i c to f i n e - g r a i n e d , and c o n t a i n s l i t t l e c h e r t . This u n it i s f a i n t l y l a m i n a t e d , but on c a s u a l e x a m i n a t i o n a p p e a r s m a s s i v e. F a v o s i t e s and s t r o m o t o p o r i d s a r e p r e s e n t in s o m e of the l o w e r m o st of the m o r e d e n s e d o l o m i t e s . The u p p e r p a r t of t h e L a k e t o w n w e a t h e rs s m o o t h with a l i g h t g r a y c o l o r In c o n t r a s t with t h e l o w e r which w e a t h e rs 114 with " s a n d p a p e r " s u r f a c e and i s n e a r l y b l a c k . D o l o t i m i t i z ed f o s s i l s a r e l i g h t e r g r a y in t h e b l a c k s t r a t a a n d ? w h e r e s i i i c i f i e d; a r e s h a d e s of g r a y and b r o w n. T h e b a s e of t h e S i l u r i a n i s t a k e n a s t h e top of a " l e o p a r d skin* b e d which c o n t a i n s s m a l l n o d u l e s of r o u n d e d c h e r t which w e a t h er i n r e l i e f and r e s e m b l e l e o p a r d h i d e . This m a r k e r bed i s not e v e r y w h e r e p r e s e n t a s a d i s t i n c t i v e unit in t h e S h e e p r o c k M o u n t a in F i e l d i d e n t i f i c a t i o n - S i l u r i a n s t r a t a a r e not s u f f i c i e n t ly d i s t i n c t i v e to b e i d e n t i f i e d with c e r t a i n t y , if only s i n g l e o u t c r o ps a r e e x a m i n e d . However, light g r a y , f i n e - g r a i n e d , t h i n - b e d d ed ( m a n y t i m e s i n d i s t i n c t ) d o l o m i t e s in t h i c k n e s s e s of m o r e t h a n 25 f e e t c a n , in m o s t i n s t a n c e s , be c o n s i d e r e d a s S i l u r i a n o r D e v o n i a n. The n a t u r e of t h e f o r m a t i o n s above and b e l o w t h e L a k e t o w n a re t h e s u r e s t m e a n s of i d e n t i f y i n g the f o r m a t i o n . Both c o n t a c t s a re a p p a r e n t l y g r a d a t i o n a l ; the b o t t om g r a d e s i n t o t h e d a r k g r a y, g e n e r a l l y g r a n u l a r , c h e r t y ( b l a c k ) , H a l y s i t e s - b e a r i n g d o l o m i t e s of t h e F i s h Haven; the top g r a d e s i n t o g r a y d o l o m i t e s of n e a r l y i d e n t i c al l i t h o l o g y . However, s m a l l r o u n d e d s a n d g r a i n s and o c c a s i o n a l low-a n g l e , c r o s s - b e d d e d s a n d s t r e a k s d i s t i n g u i s h the Devonian. Age and c o r r e l a t i o n - F o s s i l s w e r e c o l l e c t e d f r o m s i x l o c a l i t i es i n t h e L a k e t o w n d o l o m i t e ( A p p e n d i x B, P l a t e I I I ) . R. H. Waite e x a m i n e d f o u r of t h e c o l l e c t i o n s and r e p o r t e d: 115 S -3 C a m a r o t o e c h i a s p. S -4 H a l y s i t e s s p. H o w e l l e l l a s p. S t r o m o t o p o r a s p. S t r e p t e l a s m a s p. S -5 E o s p i r i f e r ? f r a g m e n ts D o u v i l l i n a cf. D. g e n i e a l a ta S-6 H a l y s i t e s s p. P e n t a m e r u s ? s p. F a v o s i t e s s p. S t r o m o t o p o r a s p. T h e D o u v i l l i n a , a c c o r d i n g to W a i t e , i s c h a r a c t e r i s t i c of the U p p e r S i l u r i a n ( N i a g a r a ). T h e L a k e t o w n d o l o m i t e i s t h e a p p r o x i m a t e age e q u i v a l e n t of p a r t of t h e B l u e B e l l d o l o m i t e of t h e T i n t i c d i s t r i c t . The i n t e r v al l a t e r n a m e d B e e c h e r d o l o m i t e by L o v e r i n g (1949) h a s b e e n r e c o g n i z ed by M o r r i s ( p e r s o n a l c o m m u n i c a t i o n ) a s e q u i v a l e n t to t h e L a k e t o wn d o l o m i t e . The L a k e t o w n d o l o m i t e i s t h e a p p r o x i m a t e age e q u i v a l e nt t o t h e R o b e r t s M o u n t a i n f o r m a t i o n and p r o b a b l y p a r t of t h e L o ne M o u n t a i n f o r m a t i o n ( r e s t r i c t e d ) of M e r r i a m (1940) in t h e E u r e k a, N e v a d a , a r e a ; and t h e R o b e r t s M o u n t a i n and J a c k V a l l e y f o r m a t i o ns a n d t h e D e c a t h o n d o l o m i t e of R u s h (1956) of w e s t e r n M i l l a r d C o u n t y , Utah. 116 S i l u r i a n - D e v o n i a n c o n t a ct The c o n t a c t b e t w e e n t h e S i l u r i a n , L a k e t o w n d o l o m i t e , and t h e o v e r l y i n g D e v o n i a n , Sevy d o l o m i t e , i s p l a c e d at t h e h o r i z on of t h e f i r s t a p p e a r a n c e s of m i n u t e , r o u n d q u a r t z s a n d g r a i n s d i s p e r s e d in m o u s e - g r a y , a p h a n i t i c d o l o m i t e . The d e n s e d o l o m i t e is c h a r a c t e r i s t i c of t h e top of t h e L a k e t o w n and of t h e e n t i r e Sevy. H o w e v e r , s a n d g r a i n s a r e a b s e n t in t h e u p p e r L a k e t o w n b e d s. S e c t i o n s m e a s u r e d in two p l a c e s a c r o s s the S i l u r i a n - D e v o n i an c o n t a c t f r o m the H a l y s i t e s - b e a r i n g c h e r t zone in t h e L a k e t o wn t o t h e s a n d - s p e c k l e d light g r a y d o l o m i t e of t h e Sevy v a r y 197 f e et i n t h i c k n e s s in a d i s t a n c e of one m i l e . The e a s t e r n s e c t i o n i s 480 f e e t t h i c k . The t o p of t h e L a k e t o w n in t h e e a s t e r n s e c t i o n i s r e p r e s e n t e d by 89 f e e t of d a r k g r a y a p h a n i t i c d o l o m i t e which w e a t h e rs l i g h t g r a y with a p i n k i s h t i n t . No u n c o n f o r m i t y was d e t e c t e d at t h e t o p of t h e d a r k g r a y u n i t . The e a s t e r n s e c t i o n i s 283 f e e t t h i c k, u s i n g t h e s a m e c o n t a c t s a s in t h e e a s t e r n s e c t i o n . The o b s e r v ed d i f f e r e n c e i n t h i c k n e s s m a y not r e p r e s e n t an e x t e n s i v e t h i n n i n g , but i n v i e w of t h e c o n s t a n c y of t h e t h i c k n e s s e s of the u n d e r l y i n g l o w er O r d o v i c i a n l i m e s t o n e s , q u a r t z i t e s and d o l o m i t e s , it would s e e m that a s h o r t i n t e r v a l a c r o s s t h e b o u n d a r y s h o u l d not b e t h i n n e d 40 p e r c e nt i n o n e m i l e u n l e s s an u n d e t e c t e d u n c o n f o r m i t y i s p r e s e n t b e t w e e n the L a k e t o w n and S e v y . Dip s l o p e - d e b r i s c o v e r s the u p p e r b e d s of the L a k e t o w n in t h e w e s t e r n s e c t i o n. DEVONIAN SYSTEM G e n e r a l s t a t e m e nt T h e D e v o n i a n s y s t e m i s r e p r e s e n t e d by 1, 732 f e e t of s t r a ta c o n s i s t i n g p r i m a r i l y of d o l o m i t e with s o m e l i m e s t o n e and q u a r t z i te i n t h e u p p e r p o r t i o n . F o r m a t i o n s r e p r e s e n t i n g the D e v o n i a n s y s t em i n t h e S h e e p r o c k M o u n t a i n s a r e c o r r e l a t e d with t h o s e r e c o g n i z e d by N o l a n (1935) in t h e Gold H i l l m i n i n g d i s t r i c t , a p p r o x i m a t e l y 66 m i l es w e s t of t h e S h e e p r o c k M o u n t a i n s . T h r e e l i t h o l o g i c a l l y d i s t i n ct f o r m a t i o n s a r e p r e s e n t : Lower D e v o n i a n ( ? ) , Sevy d o l o m i t e ; Middle D e v o n i a n , S i m o n s o n d o l o m i t e ; U p p e r D e v o n i a n ( ? ) , V i c t o r i a and P i n on P e a k f o r m a t i o n s . They a r e r e l a t i v e l y well e x p o s e d in t h e L o o k o ut H i l l s . The c o m p l e x i t y and m e t a m o r p h i s m p r e v a i l i n g in t h e West T i n t ic d i s t r i c t in t h e s o u t h e r n m o s t p a r t of t h e S h e e p r o c k M o u n t a i n s p r e c l u de c o r r e l a t i n g t h e D e v o n i a n of t h e n o r t h e r n S h e e p r o c k M o u n t a i n s with t h at a r e a , a l t h o u g h l i t h o l o g i e s a r e s i m i l a r. Sevy d o l o m i te D i s t r i b u t i o n and t h i c k n e s s - The Sevy d o l o m i t e i s p r e s e n t in two p l a c e s within the a r e a d e s c r i b e d in t h i s r e p o r t . The m o st e x t e n s i v e o u t c r o p of t h e f o r m a t i o n i s an e a s t - w e s t b e l t a p p r o x i m a t e ly 500 f e e t wide in t h e c e n t r a l p a r t of the E a s t and West L o o k o u t H i l l s . A s m a l l e r p o r t i o n of t h e Sevy c r o p s out a s a n a r r o w n o r t h - s o u t h band a b o u t one m i l e n o r t h w e s t of d i n g e r ' s m i n e in South Oak B r u sh C a n y o n . 118 T h e Sevy was m e a s u r e d In two p l a c e s a p p r o x i m a t e l y 1 m i le a p a r t in the West L o o k o u t H i l l s , the e a s t e r n s e c t i o n b e i n g 491 f e et t h i c k s and t h e w e s t e r n 355 f e e t t h i c k . The w e s t e r n s e c t i o n i s p r o b a b l y in e r r o r s i n c e the b a s e i s c o v e r e d in t h e d e p r e s s i o n b e t w e en t h e L a k e t o w n and Sevy h o g b a c k s. T o p o g r a p h i c e x p r e s s i o n - The d e n s e c h a r a c t e r of t h e Sevy d o l o m i t e m a k e s it e s p e c i a l l y r e s i s t a n t to w e a t h e r i n g , and i t f o r ms w h i t e h o g b a c k s in b o t h t h e E a s t and W e s t Lookout H i l l s . The Sevy w e a t h e r s to f o r m s t e p - l i k e t o p o g r a p h y on m o d e r a t e to s t e ep s l o p e s ( P l a t e XXI). L i t h o l o g y - The b a s e of t h e Sevy i s s i m i l a r in c o l o r and t e x t u re t o t h e u n d e r l y i n g L a k e t o w n d o l o m i t e but i s d i s t i n g u i s h e d by t h e p r e s e n c e of m e d i u m - g r a i n e d q u a r t z s a n d in a white w e a t h e r i n g m o u s e - g r a y a p h a n i t i c d o l o m i t e . The r o c k b r e a k s with s u b c o n c h o i d a i and s p l i n t e r y f r a c t u r e s and g e n e r a l l y w e a t h e r s to f o r m t a l u s , c o n s i s t i ng m a i n l y of s m a l l r e c t a n g u l a r b l o c k s . C a s u a l e x a m i n a t i o n s u g g e s t s that t h e u n i t i s m e d i u m - b e d d e d , w h e r e a s c l o s e o b s e r v a t i o n s h o w s t h e r o ck i s f i n e l y l a m i n a t e d to t h i n - b e d d e d . The s a n d g r a i n s c o n s i s t m a i n ly of g r e e n q u a r t z , r a n g e f r o m . 3 m m to 1 m m , and a r e well r o u n d ed a n d f r o s t e d . The g r a i n s a r e r a n d o m l y d i s p e r s e d in t h e d e n se d o l o m i t i c g r o u n d m a s s and in m o s t r o c k s do not s h o w any l i n e a t i o n. In p l a c e s , h o w e v e r , l o w - a n g l e c r o s s - b e d d i n g i s a p p a r e n t b e c a u s e of t h e a l i g n m e n t of t h e s a n d g r a i n s . T h r o u g h o u t the t o t a l t h i c k n e ss 119 of the S e v y , t h e s a n d g r a i n s a r e v e r y p e r s i s t e n t a n d in p l a c e s n e a r the t o p a r e e s t i m a t e d to c o m p r i s e a s m u c h a s 2 p e r c e n t of the t o t a l r o c k. F i e l d i d e n t i f i c a t i o n - The Sevy d o l o m i t e m a y be c o n f u s e d with the u p p e r m o s t b e d s of t h e L a k e t o w n d o l o m i t e if c o l o r only i s c o n s i d e r e d. The a b s e n c e of s a n d g r a i n s in t h e u p p e r L a k e t o w n s e r v e s to d i s t i n g u i sh i t f r o m the o v e r l y i n g e q u a l l y a p h a n i t i c white w e a t h e r i n g Sevy. The Sevy g e n e r a l l y s u p p o r t s l e s s v e g e t a t i o n and i s v e r y white in c o n t r a st t o t h e u n d e r l y i n g and o v e r l y i n g f o r m a t i o n s ; it i s t h e r e f o r e one of the e a s i e s t f o r m a t i o n s to d i s t i n g u i s h in the a r e a. Age and c o r r e l a t i o n - No f o s s i l s w e r e found in t h e Sevy d o l o m i t e. The Sevy r a n g e s f r o m 356 to 1, 0 4 4 f e e t in t h i c k n e s s in l e s s t h a n t h r ee m i l e s a l o n g i t s s t r i k e , w h e r e a s the S i m o n s o n r a n g e s f r o m 450 to 563 f e e t in t h i c k n e s s . The g r e a t e r r a n g e In t h i c k n e s s of t h e Sevy r e l a t i ve t o t h a t of t h e S i m o n s o n i s t a k e n to i n d i c a t e a v e r y p r o n o u n c e d u n c o n - f o r m i t h at t h e b a s e of t h e Sevy, but t h e r e c o g n i t i o n of U p p e r S i l u r i an f o s s i l s n e a r the F i s h H a v e n - L a k e t o w n c o n t a c t , t o g e t h e r with the u n c o n f o r m i t y b e t w e e n the L a k e t o w n and t h e Sevy d o l o m i t e s , i n d i c a t es t h a t t h e Sevy i s m o s t l i k e l y of E a r l y D e v o n i a n a g e. T h e Sevy d o l o m i t e i s t h e a p p r o x i m a t e age a n d / o r l i t h i c e q u i v a l e nt of t h e B e a c o n P e a k d o l o m i t e of t h e N e v a d a f o r m a t i o n and t h e Ox Yoke C a n y o n s a n d s t o n e m e m b e r of t h e N e v a d a f o r m a t i o n (Nolan, M e r r i a m, a n d W i l l i a m s , 1956, p. 42 a n d 48) n e a r E u r e k a , Nevada; the King C a n y o n d o l o m i t e of R u s h (1956) i n t h e C o n f u s i o n R a n g e , Utah; and 120 t h e m i d d l e of t h e B l u e B e l l d o l o m i t e o r the D o r a d o l o m i t e of L o v e r i n g (1949) i n t h e T i n t i c d i s t r i c t . The Sevy i s l i t h o l o g i c a l ly e q u i v a l e n t to t h e W a t e r C a n y o n f o r m a t i o n of W i l l i a m s (1948) in t h e L o g a n q u a d r a n g l e , Utah. S i m o n s o n d o l o m i te D i s t r i b u t i o n and t h i c k n e s s - The S i m o n s o n d o l o m i t e i s i n c o n f o r m a b l e c o n t a c t with t h e u n d e r l y i n g Sevy d o l o m i t e . T h e i r o u t c r op p a t t e r n s a r e s i m i l a r in t h e L o o k o u t H i l l s a r e a , b e i n g n e a r l y c e n t r a l ly l o c a t e d with an e a s t - w e s t t r e n d . The S i m o n s o n w e a t h e r s d a r k e r and g e n e r a l l y i t s b a s a l u n i t s o c c u p y dip s l o p e s of the Sevy h o g b a c k s . Like all f o r m a t i o n s in t h e n o r t h e r n S h e e p r o c k s , the S i m o n s o n i s d i s p l a c e d by a s e r i e s of n o r t h - t r e n d i n g f a u l t s . The S i m o n s o n i s 505 f e e t t h i c k ; the l o w e r c o n t a c t i s well m a r k e d , being d r a w n w h e r e white w e a t h e r i ng Sevy d o l o m i t e g i v e s way to a m o r e g r a y - b u f f w e a t h e r i n g and s a c c h - a r o i d a l t e x t u r e d , m e d l u m - g r a l n e d d o l o m i t e. T o p o g r a p h i c e x p r e s s i o n - The S i m o n s o n d o l o m i t e i s t h e l e a st well e x p o s e d of t h e D e v o n i a n f o r m a t i o n s in t h e a r e a . The n o r t h - s o u th r i d g e c r e s t s in the E a s t and West L o o k o u t H i l l s a f f o r d the m o s t f a v o r a b l e e x p o s u r e s . The f o r m a t i o n I s f a i r l y e a s i l y e r o d e d , m o s t l y l i k e ly b e c a u s e the c o a r s e n e s s of g r a i n s c o m p r i s i n g the d o l o m i t e s i s f a v o r a b le t o c h e m i c a l w e a t h e r i n g . G e n e r a l l y the S i m o n s o n o c c u r s in d r a i n a ge d e p r e s s i o n s . L i t h o l o g y - The S i m o n s o n d o l o m i t e , w h e r e m e a s u r e d , is a l m o st e n t i r e l y d o l o m i t e . The top of the Sevy d o l o m i t e was p l a c e d at the 121 b a s e of a t a n , s a c c b a r o M a l , m a s s i v e d o l o m i t e . Beds of t h e c o n f o r m a b ly o v e r l y i n g S i m o n s o n d o l o m i t e a r e g r a y to d a r k g r a y and a f f o r d a v e ry d i s t i n c t i v e c o l o r c h a n g e f r o m the white w e a t h e r i n g Sevy d o l o m i t e. The m a i n m a s s of t h e f o r m a t i o n i s m e d i u m - to c o a r s e - g r a i n e d, c r y s t a l l i n e , m e d i u m to d a r k g r a y d o l o m i t e . Bedding r a n g e s f r om l a m i n a t e d t h r o u g h m a s s i v e ; the m o r e m a s s i v e d a r k g r a y to b l a ck w e a t h e r i n g b e d s c o n t a i n f a i n t s l i g h t l y u n d u l a t o r y l a m i n a e which d i s a p p e a r within a f ew f e e t . The S i m o n s o n c h a n g e s a l o n g s t r i k e w e s t e r ly a n d within a m i l e c o n t a i n s a b e d of b l u e - g r a y l i m e s t o n e which is a p p r o x i m a t e l y 47 f e e t t h i c k . This l i m e s t o n e u n i t i s e x t r e m e ly f o s s i i i f e r o u s , g r a n u l a r to f r i a b l e and e m i t s a f e t i d o d o r when s t r u ck with a h a m m e r , and i s p r o b a b l y r e p r e s e n t a t i v e of t h e b l a c k f o s s i l - i f e r o u s d o l o m i t e s n e a r the top of t h e m e a s u r e d s e c t i o n to t h e e a s t. The u n i t s of t h i s f o r m a t i o n a l l s e e m to t h i n o r t h i c k e n a l o n g s t r i k e, a n d , t a k e n s i n g l y , a r e not r e l i a b l e a s m a p p a b i e u n i t s. F i e l d i d e n t i f i c a t i o n - The S i m o n s o n d o l o m i t e i s m a i n l y a m e d i u m - t o c o a r s e - g r a n u l a r , l a m i n a t e d , d a r k g r a y to b l a c k d o l o m i t e . The l a m i n a t i o n s a i d in d i s t i n g u i s h i n g it f r o m m o s t of t h e o t h e r d o l o m i t e s in t h e a r e a , but l a m i n a e a r e a l s o p r e s e n t in t h e F i s h Haven d o l o m i t e and t h e G u i l m e t t e f o r m a t i o n . The F i s h H a v e n i s r e a d i l y d i s t i n g u i s h e d by t h e p r e s e n c e of b r o w n and b l a c k c h e r t a s b o x w o r k and n o d u l e s ; l i t t le o r no c h e r t i s p r e s e n t in t h e S i m o n s o n . The o v e r l y i n g G u i l m e t te c o n t a i n s s i m i l a r l a m i n a t e d b l a c k d o l o m i t e s , but if a s i z a b l e o u t c r op 122 i s e x a m i n e d , white q u a r t z i t e f l o a t will u s u a l l y b e f o u n d . The 3 0 - to 5 0 - f o o t b e d of q u a r t z i t e n e a r the b a s e of t h e G u i l m e t t e s e r v e s a s a good m a r k e r f o r t h e top of t h e S i m o n s o n in t h e S h e e p r o c k M o u n t a i ns s e c t i o n . A b l a c k d o l o m i t e , which at one l o c a l i t y i s found n e a r the m i d d l e of t h e f o r m a t i o n , c o n t a i n s m a n y b r a c h i o p o d s and c o r al f r a g m e n t s . This d o l o m i t e i s m e d i u m c r y s t a l l i n e , w h e r e a s the f o s s i l s a r e c r e a m c o l o r e d and c o m p o s e d of v e r y c o a r s e d o l o m i t e. D o l o m i t i z a t i o n h a s d e s t r o y e d the i d e n t i f y i n g f e a t u r e s of t h e f o s s i l s, b u t , t h i s b e d at t h e one l o c a l i t y i s one of t h e m o s t f o s s i i i f e r o u s of t h e P a l e o z o i c f o r m a t i o n s in t h e a r e a. Age and c o r r e l a t i o n - Only one l o c a l i t y in t h e S i m o n s o n d o l o m i te c o n t a i n e d f o s s i l s , but d o l o m i t i z a t i o n of t h e f o r m a t i o n h a s l a r g e ly d e s t r o y e d the i d e n t i f y i n g f e a t u r e s of t h e f a u n a . The w r i t e r r e c o g n i z ed b r a c h i o p o d c r o s s - s e c t i o n s and C l a d o p o r a ? s p . in a d a r k g r a y to b l a c k d o l o m i t e , a p p r o x i m a t e l y 300 f e e t above t h e b a s e of the f o r m a t i o n . The q u e s t i o n a b l e C l a d o p o r a s p . and s t r a t i g r a p h ic p o s i t i o n of t h e f o r m a t i o n s t r o n g l y s u g g e s t a Middle D e v o n i a n age a n d a c o r r e l a t i o n with t h e t y p e S i m o n s o n at Gold H i l l , Utah (Nolan, 1 9 3 5 , p . 19). S e c t i o n D - 2 ( A p p e n d i x A, P l a t e I I I ) , m e a s u r e d in the W e s t Lookout H i l l s , c o n t a i n s a f a u n a f r o m l o c a l i t y DM-1 in t h e S i m o n s o n d o l o m i t e. T h i s l o c a l i t y i s in a c h e r t y and f r a c t u r e d l i m e s t o n e the d i p of which c o i n c i d e s with t h e u n d e r l y i n g and o v e r l y i n g d o l o m i t e u n i t s . Soil. 123 a n d b l o c k s of q u a r t z i t e o b s c u r e the c o n t a c t s with t h e l i m e s t o n e and d o l o m i t e . M. A. S t a l n b r o o k e x a m i n e d the c o l l e c t i o n and r e p o r t e d: P r o e t u s ? s p. A t h y r o i d ? b r a c h i o p od cf. B r a c h y t h y r i s ? s p. C a m a r o t o e c h i a ? s p. C h o n e t e s s p. C y c t i n a ? L e p t o s t r o p h i a ? P r o d u c t i d j S p i r i f e r s p. cf. S y r i n g o t h y r is T y l o t h y r i s ? S t r a p o r o l l o i d g a s t r o p od R e g a r d i n g the c o l l e c t i o n S t a i n b r o o k s t a t e s: " T h e s p e c i m e n s a r e s o m e w h a t s c r a p p y and not t o well p r e s e r v e d , so t h a t I c o u l d not do v e ry m u c h with t h e m . I i d e n t i f i e d s o m e of t h e g e n e ra but e v e n h e r e s o m e of t h e i d e n t i f i c a t i o n s a re q u e s t i o n a b l e . I a m s o r r y t h a t I c o u l d not g i v e m o re r e l i a b l e i d e n t i f i c a t i o n s , but t h e n a t u r e of the m a t e r i a l left c o n s i d e r a b l e to be d e s i r e d . To s o m e e x t e n t t h e y s e e m to be p o s s i b l y y o u n g er t h a n D e v o n i a n , but a g a i n , I c a n n o t be m o re d e f i n i t e . " T h e p r e s e n c e of the t h r u s t e d q u a r t z i t e b l o c k s o v e r l y i n g t h is a r e a s u g g e s t s t h a t t h e l i m e s t o n e c o n t a i n i n g t h e f a u n a m a y h a v e b e en d r a g g e d i n t o i t s c o i n c i d e n t p o s i t i o n and would t h u s s u b s t a n t i a te S t a i n b r o o k ' s s u s p i c i o n s of a y o u n g e r a g e. T h e S i m o n s o n d o l o m i t e i s the a p p r o x i m a t e age a n d / o r l i t h ic e q u i v a l e n t of the S e n t i n a l M o u n t a i n d o l o m i t e , W o o d p e c k e r l i m e s t o n e, a n d p r o b a b l y p a r t of the Bay S t a t e d o l o m i t e m e m b e r s of t h e N e v a da f o r m a t i o n at E u r e k a , N e v a d a . The S i m o n s o n p r o b a b l y c o r r e l a t es 124 with t h e N o a h d o l o m i t e ( L o v e r l n g , 1949) i n t h e T i n t i c m i n i n g d i s t r i c t, U t a h . The S i m o n s o n i s t h e a p p r o x i m a t e age e q u i v a l e n t to t h e l o w er p o r t i o n of t h e J e f f e r s o n d o l o m i t e (Young, 1955) in the s o u t h e rn L a k e s i d e M o u n t a i n s , Utah. V i c t o r i a a n d P i n o n P e a k f o r m a t i o n s u n d i f f e r e n t i a t ed D i s t r i b u t i o n and t h i c k n e s s - The V i c t o r i a and P i n o n P e a k f o r m a t i o n s c r o p out in a 700=»foot b e l t on t h e s o u t h s l o p e of t h e M a d i s on h o g b a c k s . No o t h e r Vic t o r l a - P i n on P e a k f a c i e s w e r e r e c o g n i z ed i n the r e m a i n d e r of t h e S h e e p r o c k M o u n t a i n s. T h e V i c t o r i a - P i n o n P e a k f o r m a t i o n s w e r e m e a s u r e d n e a r the c e n t e r of t h e W e s t L o o k o u t H i l l s , but f a u l t i n g n e a r t h e t o p n e c e s s i t a t ed t h e i n c l u s i o n of t h e t o p u n i t s a s m e a s u r e d in t h e E a s t L o o k o u t H i l l s. T h e s e c t i o n i s 736 f e e t t h i c k , but t h i s m a y b e in e r r o r b e c a u s e of r a p i d f a c i e s c h a n g e s which a r e a p p a r e n t in one m i l e d i s t a n c e. T o p o g r a p h i c e x p r e s s i o n - The f o r m a t i o n s w e a t h e r l i k e the S i m o n s o n d o l o m i t e and a r e p r e s e n t b e n e a t h t h e t a l u s c o v e r e d f o r e - s l o p e s of t h e r i d g e s f o r m e d by t h e c h e r t y , m o r e r e s i s t a n t M a d i s on l i m e s t o n e . The l i g h t g r a y to white q u a r t z i t e u n i t s of t h e f o r m a t i on a r e f r a c t u r e d and w e a t h e r l i k e t h e d o l o m i t e s above a n d b e l o w. L i t h o l o g y - The V i c t o r i a - P i n o n P e a k f o r m a t i o n s a r e s i m i l ar t o the c o n f o r m a b l y u n d e r l y i n g S i m o n s o n d o l o m i t e . The top of the S i m o n s o n d o l o m i t e i s g r a d a t i o n a l with t h e b a s a l m e m b e r s of the V i c t o r i a - P i n o n P e a k f o r m a t i o n s . The V i c t o r i a - P i n o n P e a k s e q u e n ce c o n t a i n s a p p r e c i a b l e a m o u n t s of q u a r t z i t e n e a r t h e b a s e . The b o t t om 125 of a 21 -foot u n i t of d a r k g r a y d o l o m i t i c i l m e s t o n e 3 i m m e d i a t e ly b e l ow a 3 3 - f o o t g r a y , c r o s s - b e d d e d q u a r t z i t e ^ w a s d e s i g n a t ed a s t h e c o n t a c t b e t w e e n t h e S i m o n s o n d o l o m i t e and t h e V i c t o r i a - P i n o n P e a k s t r a t a . No q u a r t z i t e i s p r e s e n t in s t r a t a a s s i g n e d to t h e S i m o n s o n d o l o m i t e . Although t h e f i n e r l a m i n a t i o n s a r e not as p r e v a l e n t a s in t h e S i m o n s o n , the i n d i v i d u a l u n i t s of g r a y , d a rk g r a y , and b l a c k d o l o m i t e s , with t h e t h i n q u a r t z i t e s , give the o u t c r o p s a l a m i n a t i o n on a l a r g e s c a l e . Some of t h e d o l o m i t e s a re c a l c a r e o u s ; all t h e c a r b o n a t e s a r e c r y s t a l l i n e and m e d i u m - g r a n u l a r. Q u a r t z i t e s r a n g e f r o m white t o g r a y i s h - t a n and a r e v e r y d e n s e, i n d i c a t i n g e x t e n s i v e c e m e n t a t i o n . Ail a r e f r a c t u r e d and s o m e show l o w - a n g l e c r o s s - b e d d i n g . Gray and light g r a y d o l o m i t e l e n s e s a re i n t e r c a l a t e d in m a n y of t h e q u a r t z i t e s . Most of the q u a r t z i t e u n i ts a r e t h i n - to m e d i u m - b e d d e d , and l e n s e s up t o 6 i n c h e s t h i c k a re p r e s e n t . L i m e s t o n e and d o l o m i t i c l i m e s t o n e a r e e r r a t i c in o c c u r r e n c e and a r e b l u e - g r a y , c r y s t a l l i n e to d e n s e , and u s u a l ly m e d i u m - b e d d e d . None of t h e s t r a t a c o m p r i s i n g the f o r m a t i o n can b e u s e d a s r e l i a b l e m a p u n i t s. F i e l d i d e n t i f i c a t i o n - The V i c t o r i a - P i n o n P e a k i s r e a d i l y d i s t i n g u i s h e d f r o m the u n d e r l y i n g S i m o n s o n , the L a k e t o w n and Ajax by t h e p r e s e n c e of t h e q u a r t z i t e u n i t s. 126 Age and c o r r e l a t i o n - The o n l y c o l l e c t i o n f r o m t h i s f o r m a t i o n w a s s c r a m b l e d and l o s t in t r a n s i t to t h e l a b o r a t o r y . The V i c t o r i a - P i n o n P e a k s t r a t a by i t s l i t h o l o g y a n d s t r a t i g r a p h i c p o s i t i on i s a s s i g n e d to t h e M i d d l e and U p p e r ? D e v o n i a n, T h e V i c t o r i a - P i n o n P e a k s t r a t a a r e t h e a p p r o x i m a t e age e q u i v a l e nt of t h e G u i l m e t t e f o r m a t i o n of N o l a n (1935) in the Deep C r e e k M o u n t a i n s; t h e V i c t o r i a q u a r t z i t e and p a r t of t h e P i n o n P e a k l i m e s t o n e of L o u g h l in (1919) at T i n t i c , Utah; and p a r t of t h e J e f f e r s o n ( W i l l i a m s , 1948) in n o r t h e a s t e r n Utah, D e v o n i a n - M i s s i s s i p p i a n c o n t a ct T h e c o n t a c t b e t w e e n the D e v o n i a n and M i s s i s s i p p i a n s y s t e ms was a r b i t r a r i l y p l a c e d at t h e top of t h e u p p e r m o s t q u a r t z i t e of the V i c t o r i a - P i n o n P e a k f o r m a t i o n s . The b a s a l M a d i s o n i s a m e d i u m - t o c o a r s e - g r a i n e d l i m e s t o n e which, in p l a c e s , i s s i i t y . T h e r e i s no c h e r t in t h e l o w e r u n i t , and f ew b e d s r e s e m b l e the f l a g g y l i m e s t o n es of t h e D e s e r e t - H u m b u g f o r m a t i o n . No u n c o n f o r m i t y b e t w e e n the D e v o n i a n and M i s s i s s i p p i a n r o c k s was r e c o g n i z e d in t h e S h e e p r o ck M o u n t a i n s . D e t a i l e d p a l e o n t o i o g i c work i s n e e d e d to e s t a b l i s h the e x a c t n a t u r e of t h e b o u n d a r y b e t w e e n t h e D e v o n i a n and M i s s i s s i p p i an s y s t e m s in t h e S h e e p r o c k M o u n t a i n s a r e a. 127 MISSISSIPPIAN SYSTEM G e n e r a l s t a t e m e nt T h e M i s s i s s i p p i a n p e r i o d i s r e p r e s e n t e d by o v e r 5, 760 f e e t of s t r a t a , c o n s i s t i n g m o s t l y of c h e m i c a l s e d i m e n t s . L i m e s t o n e i s the m o s t c o m m o n r o c k f o l l o w e d in a b u n d a n c e by b l a c k s h a l e , q u a r t z i t e, a n d c h e r t. F o u r f o r m a t i o n s a r e p r e s e n t r - t h e M a d i s o n , D e s e r e t , Humbug, and .Gr^feat/Blue. H o w e v e r , the e x t r e m e v a r i a b i l i t y of t h e M i s s i s s i p p i a n in t h i s a r e a » i n c o m p a r i s o n with n e a r b y s e c t i o n s , w a r r a n t s a d i f f e r e nt t r e a t m e n t of t h e u n i t s . The M a d i s o n l i m e s t o n e i s e s s e n t i a l l y the s a m e a s s u r r o u n d i n g d i s t r i c t s . The D e s e r e t i s u n i d e n t i f i e d o r m i s s i ng i n the a r e a and it i s thought t h a t t h i s n a m e s h d u i d be d r o p p e d o r c o m b i n e d with t h e H u m b u g . The G r e a t Blue i s e x t r e m e l y t h i c k and i n c l u d es a t h i c k b l a c k s h a l e in t h e c e n t e r which i s e n t i t l e d to m e m b e r s t a t u s, a n d h e n c e f o r t h will b e r e f e r r e d to a s t h e C h i u l o s m e m b e r (type l o c a l i t y i s i n E a s t T i n t i c M o u n t a i n s ; n a m e d by U. S. G e o l o g i c al S u r v e y ) . The G r e a t B l u e f o r m a t i o n , as d e f i n e d , c o n s i s t s of t h e L o w er G r e a t B l u e l i m e s t o n e , the C h i u l o s s h a l e m e m b e r , and t h e U p p er G r e a t B l u e l i m e s t o n e. M a d i s o n l i m e s t o ne D i s t r i b u t i o n and t h i c k n e s s - The M a d i s o n l i m e s t o n e c r o p s out i n a b e l t a p p r o x i m a t e l y 800 f e e t wide i n t h e n o r t h e r n end of t h e E a st a n d West L o o k o u t H i l l s . The L o w e r M i s s i s s i p p i a n s t r a t a m a i n t a in 128 a r e g i o n a l d i p which i s m o r e n o r t h e r l y t h a n t h e e a r l y P a l e o z o i c s e d i m e n t s l y i n g to t h e s o u t h ; i n t h e v i c i n i t y of L o o k o u t P a s s , the m o re w e s t e r l y s t r i k e of t h e r o c k s c a n b e a t t r i b u t e d to f a u l t i n g . Madison l i m e s t o n e i s a b s e n t i n t h e r e m a i n d e r of t h e S h e e p r o c k M o u n t a i n s and i n t h e e a s t e r n p a r t of the S i m p s o n M o u n t a i n s. T h e M a d i s o n l i m e s t o n e i s 623 f e e t t h i c k i n t h e E a s t L o o k o u t H i l ls a r e a . The w e s t e r n m o s t e x p o s u r e s of t h e M a d i s o n l i m e s t o n e a re g e n e r a l l y u n r e c o g n i z a b l e , b e i n g c o v e r e d by s i l i c i f i e d b r e c c i a t ed r o c k s a n d a l l u v i u m. T o p o g r a p h i c e x p r e s s i o n - The c h e r t y p o r t i o n of t h e M a d i s on l i m e s t o n e h a s c o n s i d e r a b l e r e s i s t a n c e to w e a t h e r i n g , r e s u l t i ng i n a r e l a t i v e l y h i g h e a s t - w e s t r i d g e t r a v e r s i n g t h e h i l l s i n the n o r t h e r n p a r t of t h e a r e a . The u n d e r l y i n g D e v o n i a n s t r a t a e r o de m o r e e a s i l y , f o r m i n g a long low r i d g e b e t w e e n t h e b a s a l M a d i s on a n d t h e F i s h H a v e n d o l o m i t e . The top of t h e M a d i s o n l i m e s t o ne i s m a r k e d by a d i p s l o p e f o r m e d by w e a t h e r i n g of t h e w e a k e r limy s a n d s t o n e s of t h e c o n f o r m a b l y o v e r l y i n g D e s e r e t - H u m b u g f o r m a t i o n. L i t h o l o g y - The b a s e of t h e M a d i s o n i s not a s h a r p l i t h o l o g ic c o n t a c t and w a s a r b i t r a r i l y t a k e n a s the t o p of t h e h i g h e s t white q u a r t z i t e in t h e u n d e r l y i n g V i c t o r i a - P i n o n P e a k f o r m a t i o n s . The b e d s n e a r the b a s e of t h e M a d i s o n a r e not c h e r t y and in p l a c es c o n t a i n m u c h s i l t , which c a u s e s t h e b e d s to w e a t h e r in f l a g g y b l o c k s. C h e r t o c c u r s a s b a n d s 1 t o 2 i n c h e s t h i c k at i n t e r v a l s of 3 t o 6 129 i n c h e s in t h e c r y s t a l l i n e g r a y l i m e s t o n e . Near t h e t o p a f ew b a n ds r a n g i n g up t o 6 f e e t in t h i c k n e s s a r e c o m p o s e d a l m o s t e n t i r e l y of x r i n o i d r e m a i n s. F i e l d i d e n t i f i c a t i o n - The M a d i s o n l i m e s t o n e i s e a s y to r e c o g n i z e. The d a r k c h e r t b a n d s a r e v e r y d i s t i n c t i v e , b e i n g f r o m 1 t o 2 I n c h es t h i c k s p a c e d at n e a r l y r e g u l a r 3 - t o 6 - i n c h i n t e r v a l s in b l u e - g r ay l i m e s t o n e . C r i n o i d c o l u m n a l s a r e e s p e c i a l l y a b u n d a n t in s e v e r al b e d s n e a r t h e t o p of t h e f o r m a t i o n , but t h e s e b e d s do not s e e m to p e r s i s t f o r any g r e a t l e n g t h a l o n g t h e s t r i k e . The u p p e r c o n t a c t is a v e r y p r o n o u n c e d dip s l o p e f o r m e d by w e a t h e r i n g b a c k of t h e soft D e s e r e t - H u m b u g f o r m a t i o n. Age and c o r r e l a t i o n - M a d i s o n l i m e s t o n e o r M a d i s o n e q u i v a l e n ts a r e p r e s e n t at O p h l r and i n t h e E a s t T i n t i c M o u n t a i n s , a s well a s in t h e n o r t h e r n Onaqui M o u n t a i n s , and at Gold H i l l , U t a h . The M a d i s on l i m e s t o n e i s a m o n g t h e m o s t w i d e s p r e a d and e a s i l y r e c o g n i z e d f o r m a t i o n s of t h e Rocky M o u n t a i n m i o g e o s y n c l i n e ( M i l l a r d B e l t ) a n d the U t a h - W y o m i n g Shelf. In t h e E a s t T i n t i c M o u n t a i n s , M o r r i s et a l. h a v e s u b d i v i d e d t h e M a d i s o n i n t o t h e F i t c h v i l l e and t h e G a r d i s on f o r m a t i o n s , which, f o r t h a t r e g i o n , c o n s t i t u t e t h e M a d i s o n g r o u p. E l s e w h e r e in U t a h t h e M a d i s o n i s m o r e of a u n i f o r m l i t h o l o g y ; h o w e v e r, i n t h e S h e e p r o c k M o u n t a i n s the b a ^ a i 200 f e e t m a y be r e p r e s e n t a t i ve of t h e F i t c h v i l l e f o r m a t i o n of t h e E a s t T i n t i c M o u n t a i n s. t 130 F o s s i l s w e r e c o l l e c t e d f r o m s e v e r a l l o c a l i t i e s . Dr. W i l l i am L e e S t o k e s and t h e w r i t e r i d e n t i f i e d the M a t e r i a l l i s t e d b e l o w: M-1-, a p p r o x i m a t e l y 250 f e e t above b a se C h o n e t e s l o ^ a n e n s is O s t r a c o d s C r i n o i d f r a g m e n ts M - 7 , n e a r b a se E x o c h o p s ? s p. C o m p o s i t a h u m i l is M a r t i n i a r o s t r a ta P r o d u c t u s g a l l a t i n e n s is S c h u c h e r t e l l a c h e m u n g e n s is S t r a p a r e i l u s o p h i r e n s is M - 9 , n e a r b a se S p i r i f e r c e n t r o n a t us T h e f a u n a l i s t e d i s t y p i c a l of t h e M a d i s o n l i m e s t o n e in the O q u i r r h and t h e D e e p C r e e k M o u n t a i n s , Utah. T h e M a d i s o n l i m e s t o n e c o m p a r e s f a v o r a b l e in t h i c k n e s s with s e c t i o n s at Gold H i l l , O q u i r r h , E a s t T i n t i c , the c e n t r a l W a s a t c h, and s o u t h e r n L a k e s i d e M o u n t a i n s. T h e p r e v a l e n t p h o s p h a t i c s h a l e which c h a r a c t e r i z e s the M a d i s o n - D e s e r e t c o n t a c t at O p h i r ( G i l l u l y , p . 24) i s a b s e n t or i s c o n c e a l e d In t h e S h e e p r o c k M o u n t a i n s r e g i o n . The p r e s e n c e of r e d d i s h w e a t h e r i n g , s i l t y and s o m e w h a t s h a l y l i m e s t o n e s in the s e c t i o n was t a k e n to m a r k the b a s e of t h e D e s e r e t . This s a d d l e - f o r m i n g u n i t m a y c o n c e a l the p h o s p h a t i c s h a l e s , which c h a r a c t e r i ze t h e d i v i s i o n b e t w e e n the M a d i s o n and t h e c o n f o r m a b l y o v e r l y i ng D e s e r e t l i m e s t o n e of n e a r b y s e c t i o n s. 131 The M a d i s o n l i m e s t o n e in the S h e e p r o c k s i s t r a n s i t i o n a l with t h e a p p a r e n t l y c o n f o r m a b l e u n d e r l y i n g D e v o n i a n s t r a t a . M o r r is ( p e r s o n a l c o m m u n i c a t i o n , 1956) s t a t e s t h a t t h e D e v o n i a n - P i n o n P e ak f o r m a t i o n , c a n n o t be l o g i c a l l y s e p a r a t e d f r o m the F i t c h v i l l e ( b a s al M a d i s o n ) f o r m a t i o n . A s i m i l a r s i t u a t i o n p r o b a b l y e x i s t s in the S h e e p r o c k M o u n t a i n s a r e a and f o r c o n v e n i e n c e t h e t o p of t h e u p p e r m o s t q u a r t z i t e in t h e c o n f o r m a b l y u n d e r l y i n g V i c t o r i a - P i n o n P e ak f o r m a t i o n was t a k e n a s the b a s e of the M a d i s o n l i m e s t o n e . Close p a i e o n t o l o g i c c o n t r o l i s n e c e s s a r y . f o r e s t a b l i s h i n g the e x a c t t i me b o u n d a r y . C o r r e l a t i o n with o t h e r Utah s e c t i o n s i s b a s e d p r i m a r i l y on t he f a u n a and g r o s s l i t h o l o g i c s i m i l a r i t i e s and n o t t h e c h a r a c t e r i s t i c s of t h e u p p e r a n d l o w e r c o n t a c t s. T h e M a d i s o n l i m e s t o n e i s t h e a p p r o x i m a t e age e q u i v a l e n t of m o s t of t h e G a r d n e r f o r m a t i o n of L o u g h l i n (1919) in t h e T i n t ic d i s t r i c t ; the J o a n a l i m e s t o n e of S p e n c e r (1917) of c e n t r a l N e v a da a r e a ; and t h e T o p a c h e l i m e s t o n e of B u t l e r (1913) of t h e San F r a n c i s co r e g i o n U t a h . The M a d i s o n i s p r e s e n t in t h e O q u i r r h , Deep C r e e k, a n d L a k e s i d e M o u n t a i n s and o t h e r r a n g e s in U t a h a n d t h e G r e at B a s i n r e g i o n. 132 D e s e r e t - H u m b u g f o r m a t i on G e n e r a l - The D e s e r e t and Humbug f o r m a t i o n s c a n n o t be d i f f e r e n t i a t e d in t h e S h e e p r o c k M o u n t a i n s , a n d t h e i r d o m i n a nt l i t h o i o g i e s a r e r e v e r s e to t h a t of t h e i r t y p e s e c t i o n s in the O q u i r r h M o u n t a i n s , a p p r o x i m a t e l y 20 m i l e s to t h e n o r t h . The u n i t c o n t a i n s m o r e s a n d in t h e l o w e r half and a h i g h p e r c e n t a ge of l i m e s t o n e in t h e u p p e r half ,and f o r t h i s r e a s o n , the f o r m a t i o ns h a v e not b e e n d i f f e r e n t i a t e d and a r e d i s c u s s e d a s a s i n g l e u n i t. E v i d e n t l y a f a c i e s c h a n g e a c c o u n t s f o r the r e v e r s a l of l i t h o l o g y. P a l e o n t o l o g i s t s and s t r a t i g r a p h e r s m a y at s o m e f u t u r e d a t e be a b le t o s u b d i v i d e the C h e s t e r f a u n a in t h i s z o n e and e s t a b l i s h a s u i t a b le t i m e b o u n d a r y . The w r i t e r i s of the o p i n i o n t h a t to a t t e m p t a l i t h o l o g i c d i v i s i o n would b e u n w a r r a n t e d and p e r h a p s m i s l e a d i n g. D i s t r i b u t i o n and t h i c k n e s s - The D e s e r e t - H u m b u g f o r m a t i on c r o p s out n e a r the n o r t h e r n end of t h e E a s t and W e s t L o o k o u t H i l ls i n a n e a r l y c o n t i n u o u s b a n d 900 f e e t wide i n an e a s t - w e s t d i r e c t i o n. The b e d s dip t o t h e n o r t h at 40 d e g r e e s and c o n f o r m a b l y o v e r l i e the M a d i s o n l i m e s t o n e . No o t h e r D e s e r e t - H u m b u g s t r a t a c r o p out in t h e S h e e p r o c k M o u n t a i n s r e g i o n. Two s e c t i o n s of t h e D e s e r e t - H u m b u g f o r m a t i o n ( A p p e n d i x A and P l a t e III) w e r e m e a s u r e d in t h e E a s t and West L o o k o u t H i l l s a r e as with t h i c k n e s s e s of 1 , 1 4 5 f e e t and 1 , 1 6 5 f e e t , r e s p e c t i v e l y. 133 T o p o g r a p h i c e x p r e s s i o n - The s a n d y l i m e s t o n e s and s a n d s t o n es of t h e D e s e r e t - H u m b u g f o r m a t i o n w e a t h e r to f o r m s l o p e s . F l a g gy d e b r i s c o n c e a l s m u c h of t h e s t r a t a . In a i l p l a c e s t h e m a s s i ve w e a t h e r i n g o v e r l y i n g l o w e r G r e a t B l u e l i m e s t o n e f o r m s c l i f f s on the c r e s t of t h e r i d g e s . D e b r i s f r o m the G r e a t B l u e f o r m a t i o n m a s ks t h e c o n t a c t at m o s t l o c a l i t i e s. L i t h o l o g y - The M a d i s o n l i m e s t o n e g r a d e s i n t o t h e c o n f o r m a b ly o v e r l y i n g D e s e r e t - H u m b u g u n i t . The c o n t a c t i s s h a r p , b e i n g at a p l a ce w h e r e t h e t y p i c a l , c h e r t - b a n d e d , b l u e - g r a y , m e d i u m - g r a i n e d l i m e s t o n e s of t h e M a d i s o n l i m e s t o n e a r e o v e r l a i n by s a n d y , f l a g g y , r e d d i s h - t a n , w e a t h e r i n g l i m e s t o n e s of the D e s e r e t - H u m b u g f o r m a t i o n s . The D e s e r e t - H u m b u g i s c h a r a c t e r i s t i c a l l y a s e r i e s of r e l a t i v e l y t h i ck l i m e s t o n e s and s a n d s t o n e s with l i m e s t o n e c o m p r i s i n g about t h r ee q u a r t e r s of t h e t o t a l . Many of t h e s a n d s t o n e s a r e q u a r t z i t i c and a l l a r e g r a d a t i o n a l with a d j a c e n t l i m e s t o n e s . A f ew of t h e l i m e s t o n es s h o w c r o s s - b e d d i n g a c c e n t u a t e d by t h e p r e s e n c e of s a n d s t r e a k s. T h e b a s a l u n i t s of t h e f o r m a t i o n a r e s i i t y and w e a t h e r p i n k i s h - t a n. F l a g g y w e a t h e r i n g , p o o r l y e x p o s e d b e d s c h a r a c t e r i z e the b a s al 360 f e e t of t h e D e s e r e t - H u m b u g f o r m a t i o n . A f ew of t h e l i m e s t o n es n e a r the c e n t e r of the s e q u e n c e c o n t a i n s m a l l c h e r t n o d u l e s. T h e c o n t a c t b e t w e e n t h e D e s e r e t - H u m b u g and t h e M a d i s on l i m e s t o n e i s c o n f o r m a b l e , b u t i s p o o r l y e x p o s e d. 134 F i e l d i d e n t i f i c a t i o n = T h e D e s e r e t - H u m b u g f o r m a t i o n is r e c o g n i z e d by t h e a b u n d a n c e of r e d d i s h - y e l l o w to p u r p l i s h , flaggy s a n d y l i m e s t o n e which c o n t a i n s an a b u n d a n c e of b r y o z o a . The top i s r a t h e r v a g u e and g r a d a t i o n a l I n t o t h e c o n f o r m a b l y o v e r l y i ng G r e a t B l u e f o r m a t i o n and I s t a k e n at a p o i n t w h e r e the l i m e s t o n es b e c o m e m o r e m a s s i v e . Typical c h e r t y M a d i s o n c o n f o r m a b l y u n d e r l i es t h e f l a g g y l i m e s t o n e s of t h e D e s e r e t - H u m b u g. Age and c o r r e l a t i o n - F o s s i l s w e r e c o l l e c t e d f r o m t h r ee l o c a l i t i e s ( A p p e n d i x B a n d P l a t e III) in t h e D e s e r e t - H u m b u g f o r m a t i o n . Mr. W a l t e r S a d l i c k i d e n t i f i e d t h e m a t e r i a l f r o m l o c a l i ty a n d r e p o r t e d: M - 5 F a b e r o p h y l l u m cf. F . a r a n e o s um B i a s t o i d f r a g m e nt T r i p l o p h y l l i t i e s ( T r i p l o p h y l l i t e s ) o t c l i n a t us F e n e s t e l l a cf. F \ n o d u l o s a P h i l l i ps S a d l i c k r e p o r t s t h a t W. H„ E a s t o n r e c e n t l y d e s c r i b ed T r i p l o p h y l l i t i e s f r o m the S a l e m and W a r s a w l i m e s t o n e of the l o w e r M e r a m e c i a n s e r i e s in t h e t y p e M i s s i s s i p p i a n a r e a. T h e D e s e r e t - H u m b u g f o r m a t i o n s ( u n d i f f e r e n t i a t e d ) a r e the a p p r o x i m a t e age e q u i v a l e n t of t h e t y p e D e s e r e t and Humbug f o r m a t i o n s of G l l l u l y (1932) in t h e O q u i r r h M o u n t a i n s , Utah; the Woodman f o r m a t i o n of N o l a n (1935) at Gold H i l l , Utah; the l o w er p a r t of the B r a z e r f o r m a t i o n of R i c h a r d s o n (1913) in t h e n o r t h e a s t e r n Utah r e g i o n ; and p r o b a b l y p a r t of t h e C h a i n m a n s h a le 135 of S p e n c e r (1917) n e a r E l y , N e v a d a, G r e a t Blue f o r m a t i on D i s t r i b u t i o n and t h i c k n e s s - The G r e a t B l u e f o r m a t i o n c r o ps out on t h e n o r t h e r n e x t r e m i t y of t h e L o o k o u t H i l l s and d i s a p p e a rs b e n e a t h t h e a l l u v i um n o r t h of t h e r o a d to S i m p s o n S p r i n g s . The f o r m a t i o n i s d i v i d e d i n t o t h r e e p a r t s ; a l o w e r l i m e s t o n e , a s h a l e , and a n u p p e r l i m e s t o n e . Lookout P a s s , a s a d d l e - l i k e d i v i d e , on t h e r o ad f r o m V e r n o n to S i m p s o n S p r i n g s , m a r k s t h e p o s i t i o n of t h e m i d d le s h a l e m e m b e r and t h e t e r m i n u s of n o r t h e r l y dip of t h e r o c k s . The u p p e r l i m e s t o n e , lying n o r t h of t h e r o a d , i s n e a r l y f l a t , dipping s l i g h t l y to t h e e a s t ; a f a u l t t r e n d i n g f r o m NW to SE t h r o u g h Lookout P a s s i s r e s p o n s i b l e f o r the c h a n g e in a t t i t u d e of t h e r o c k s . The G r e a t B l u e f o r m a t i o n i s n o t c o m p l e t e l y e x p o s e d , and t h e o v e r l y i ng M a n n i n g C a n y o n s h a l e and an unknown p o r t i o n of t h e G r e a t Blue h a v e b e e n r e m o v e d by e r o s i o n . The u p p e r m e m b e r of t h e G r e at B l u e i s t e r m i n a t e d by f a u l t i n g on b o t h t h e n o r t h and w e s t s i d e s. T h e G r e a t B l u e f o r m a t i o n h a s an a g g r e g a t e t h i c k n e s s of 4 , 1 3 9 p l us f e e t , b e i n g d i v i d e d a s f o l l o w s : the L o w e r l i m e s t o n e , 911 f e e t ; the C h i u l o s s h a l e m e m b e r , 1, 818 p l u s f e e t ; t h e Ij)pper l i m e s t o n e , 1,410 p l u s f e e t . Since t h e two u p p e r u n i t s a r e i n c o m p l e t e the G r e a t Blue f o r m a t i o n m a y t o t a l m o r e t h a n 4, 500 f e e t . No t h i n n i n g was d e t e c t e d, but t h e e x p o s u r e i s of l i m i t e d e x t e n t a l o n g s t r i k e. 136 T o p o g r a p h i c e x p r e s s i o n - The l i m e s t o n e p o r t i o n s of the G r e a t Blue f o r m a t i o n w e a t h e r to f o r m c l i f f s and r i d g e s , w h e r e as t h e i n t e r v e n i n g s h a l e unit f o r m s s a d d l e s . Except f o r the q u a r t z i t e i n t e r b e d s , the s h a l e i s s e l d o m e x p o s e d and t h e n only i n g u l c h e s w h e r e o n l y s m a l l p o r t i o n s a r e v i s i b l e . The u p p e r l i m e s t o n e i s t h e m o s t p r o m i n e n t and f o r m s w e s t - f a c i n g c l i f f s , m a n y of w h i c h a r e n e a r l y v e r t i c a l. L i t h o l o g y - The u p p e r G r e a t B l u e l i m e s t o n e i s a l m o s t c o m p l e t e ly a m e d i u m - g r a i n e d l i m e s t o n e . The l o w e r half i s b l u e - g r a y , w h e r e as t h e u p p e r half c o n t a i n s m o r e g r a y s t r a t a . The b a s e of t h e u n i t is n o t e x p o s e d and i s in f a u l t c o n t a c t with the C h i u l o s m e m b e r at L o o k o u t P a s s w h e r e e r o s i o n h a s p r o v i d e d the b e s t e x p o s u r e of s o me of t h e l o w e r m o s t b e d s * Black c h e r t i s p r e s e n t a s b a n d s and n o d u l es i n m a n y of t h e u n i t s . C h e r t i s n o t a b u n d a n t , except l o c a l l y , and p e r s i s t s at i n t e r v a l s t h r o u g h o u t t h e e n t i r e s e c t i o n . A t a n c a l c a r e o us s l i t s t o n e i s p r e s e n t about 430 f e e t f r o m the t o p of t h e m e a s u r ed s e c t i o n . E r o s i o n h a s r e m o v e d an e s t i m a t e d 200 to 300 f e e t of b e ds r e p r e s e n t i n g t h e t r a n s i t i o n zone of t h e c o n f o r m a b l y o v e r l y i ng M a n n i n g Canyon s h a l e . C o r a l s and b r a c h i o p o d s a r e a b u n d a n t in v a r i o u s z o n e s t h r o u g h o u t t h e f o r m a t i o n . Most o b v i o u s a re t h e l a r g e c u p c o r a l s in t h e l o w e r one t h i r d of t h e u n i t. . T h e C h i u l o s m e m b e r = T h i s u n i t i s p r i m a r i l y a b l a c k f i s s i le s h a l e with m a n y i n t e r b e d d e d r i b s of q u a r t z i t e n e a r the c e n t e r. 137 E x c e p t f o r the q u a r t z i t e the s t r a t a w e a t h e r e a s i l y to f o r m low c o v e r e d a r e a s in c o n t r a s t to t h e c l i f f - f o r m i n g m a s s i v e u p p e r and l o w e r l i m e s t o n e m e m b e r s . At one p l a c e s c a t t e r e d i r r e g u l a r b l a ck c h e r t was o b s e r v e d in t h e s h a l e ; it i s of p a r t i c u l a r i n t e r e st b e c a u s e of t h e f i n e g r a n u l e s of m a r c a s i t e d i s p e r s e d in t h e m a s s . Much of t h e s h a l e i s b r o k e n a n d t h e f r a c t u r e s a r e i i m o n i t e - s t a i n e d. I t s e e m s r e a s o n a b l e to a s s u m e t h a t m o s t of t h e i r o n o x i d e o r i g i n a t ed f r o m d e c o m p o s i t i o n of t h e i r o n s u l p h i d e s within t h e s h a l e . No f o s s i ls w e r e found in t h e b l a c k s h a l e w h e r e s u l p h i d e s o c c u r . The l a c k of a s a n d y f r a c t i o n within m o s t of t h e s h a l e s e e m s to i n d i c a t e t h e a b s e n ce of a v i g o r o u s t r a n s p o r t a t i o n a g e n t ,which in t u r n would i n d i c a t e a q u i e s c e n t c o n d i t i o n a n d p o o r v e n t i l a t i o n of a r e s t r i c t e d a q u e o u s e n v i r o n m e n t . This s t a b i l i t y and t o x i c i t y would be a p o o r e n v i r o n m e nt f o r any m e g a s c o p i c life d e p e n d e n t upon o x y g e n . The t h i c k n e s s of t h e u n i t d o e s i n d i c a t e t h a t t h e s h a l e h a d c o n s i d e r a b l e a r e a l d i m e n s i o n s , and it m a y b e p e r m i s s i b l e to s u s p e c t t h a t t h e l e s s t o x ic m a r g i n a l a r e a s c o n t a i n e d m u c h p l a n t a n d a n i m a l l i f e ; t h a t on d e a t h t h e s e f o r m s r o t t e d and w e r e b u r i e d r e l a t i v e l y c l o s e to t h e ir l i f e z o n e s ; and t h a t t h e e x p a n s e of t h e t o x i c m a s s was s u f f i c i e n t ly wide to d i s c o u r a g e carcass d i s p e r s a l ' o v e r t h e e n t i r e e x p a n s e. T a n , m e d i u m - g r a i n e d , c r o s s - b e d d e d q u a r t z i t e s with a b u n d a nt i i m o n i t e s t a i n s a s d i s p e r s e d s p o t s and b l o c k s b e c o m e p r o m i n e nt about 805 f e e t above t h e b a s e and a r e p r e s e n t f o r the n e x t 450 f e e t. 138 Much b l a c k s h a l e i s i n t e r b e d d e d w i t h t h e q u a r t z i t e , but t h e w e a t h e r i ng d i f f e r e n t i a l of q u a r t z i t e v s . s h a l e p r o m o t e s an e x p o s u r e which is d o m i n a n t l y q u a r t z i t e and q u a r t z i t e b l o c k s . C a l a m i t e s s p e c i es was found in t h e q u a r t z i t e z o n e s . The s t a l k s a r e p o o r l y p r e s e r v ed but a r e s e l d o m m a s h e d ; t h i s would i n d i c a t e t h a t the p l a n t s w e r e g r o w i ng n e a r the p l a c e s of b u r i a l . The c r o s s - b e d d i n g i n d i c a t e s a r a p i d influx of s a n d p r o b a b l y t h e r e s u l t of v i g o r o u s t o r r e n t i a l r a i n f a l l on a n e i g h - b o r i n g h i g h l a n d . Above t h e q u a r t z i t e s t r a t a i s m o r e b l a c k s h a le a n d s a n d y r e d d i s h - t a n w e a t h e r i n g , f o s s i l i f e r o u s , flaggy l i m e s t o n e . L i m e s t o n e b e c o m e s t h e d o m i n a n t lithok»gy i n t h e u p p e r m o s t b e d s . A f ew g r i t t y b e d s and s o m e r e d d i s h q u a r t z i t e s a r e a l s o p r e s e n t , as a r e a f ew b e d s of s h e l l c o n g l o m e r a t e s . T h e s e b e d s a r e n e a r l y v e r t i c a l in a r e a s of b e s t e x p o s u r e and a r e p r o b a b l y t y p i c a l of t h e t o p of t h e s h a le m e m b e r . The a b u n d a n c e of l i m e s t o n e i n d i c a t e s a t r a n s i t i o n , and it i s e s t i m a t e d t h a t t y p i c a l u p p e r G r e a t Blue l i m e s t o n e would c o m m e n ce o n l y a f ew h u n d r e d f e e t a b o v e. T h e l o w e r G r e a t B l u e l i m e s t o n e i s c o n f o r m a b l e with t h e o v e r l y i n g C h i u l o s s h a l e and t h e u n d e r l y i n g Humbug f o r m a t i o n . The top of t h e l o w e r G r e a t Blue i s e a s i l y d i s t i n g u i s h e d f r o m the b a s al s h a l e s of t h e C h i u l o s m e m b e r , and w h e r e v e r r e l i e f i s p r o m i n e n t the t o p of t h e l o w e r G r e a t B l u e f o r m s a dip s l o p e . The l i m e s t o n e s c o m p r i s i n g t h e l o w e r G r e a t Blue a r e v e r y s i m i l a r to t h o s e of t h e u p p er l i m e s t o n e s . L a r g e cup c o r a l s , b r a c h i o p o d s , and g a s t r o p o d s o c c ur
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