| OCR Text |
Show 50 Survey. However, they are widely used by the miner and prospector and convenience J u s t i f i e s t h e i r use in t h i s r e p o r t. On weathered slopes the two u n i t s stand out sharply because of a color difference as well as v a r i a t i o n s in the character of the slope. The Brushy Basin or upper member (see p i . 8) forms gray to greenish-gray slopes with local and r e l a t i v e ly low standstone c l i f f s . The lower or Salt Wash member (see p i s . 6, 7 and 8) forms a s e r i e s of sandstone c l i f f s and a l t e r n a t e slopes with an o v e r - a l l color that i s predominantly brown to brownish-gray. The boundary between the lower and upper members i s marked in the slopes of the canyons by a.conspicuous f l a t area or bench that forms above the thick sandstone, which i s the p r i n c i p a l ore-bearing stratum and occurs at the top of the Brushy Basin member. The differenc e in the physical character of the two format i o n s i s brought out by measurements published by Fischerl° as follows: Section of Morrison formation at the Dolores group of mines, near the junction of Dolores and San Miguel Rivers, Montrose County, Colorado Dakota(?) sandstone; Feet Sandstone, white, weathering brown; medium- to coarse-grained, with Not lenses of conglomerate; resistant mea-and cliff-forming sured 10Fischer R. P., Vanadium deposits of Colorado and Utah; U. S. Geol. Survey Bull. 936-P, p. 375, 1942. |
