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Show [ 174 ] 296 lien relatively to t~1e formations farther east, I am inclinecl to rcf~n it to tl cretaceous formatwn. le Lono-itndc D 0 , latitndc 39°; Sm.ok.IJ Ifill ?'it,e?·.-The, pccimcn fro 11 . ocality are numbered 26, 29, 31, 33, and 8. Th y all bear a si mi larml ns acter, an d t I1 e {.o ss1.I ·arc a I'1 I { L m. cac1 1 . , l' I re rock 1.s an il11JHlrc litl(l f' c 1a r. · · I (' d It I ,s 1o ne pretty co111pact, va.ryrng Ill co or rom u Y'~ lowish to ushy browr d' a b om~ dl.l l g 1.1 1 s I1 e II s o {' a speci.C s o I' f 110c ramus. (S"e c de criptior 1.) r, an Th1s rock probably belo11 g~ to tire rrctaCI'Ons fornrution · the lower t of which has been intlicate<.l by Dr. lVIortorr a~ extcutli ll o· iuto 1 0111·s··par 1 d M . . n ... . lttlla Ar GlllSas, an tsso tll't. ' Altlrollgh the spc?irnen. fron~ this locality bc:n.a n~orc clnse rrsemhlarrcc to the nppc•r part o( the fonnat1011, I do not feel JllsldtL'd iu referrinrr tlr• to any ot I1 er pen· ot1. '1' 1u •s 1r 0rmat·w n eVJ·C Je .u tl y und ·rlics In rete troa ctse omf couutry, all(l xr ' nds fur towards the hi.lse of tile Hneky mon11 rains. J ... on~itud 105°, l ~ ti tud c 39°.-:rlt ' spccim ns from th i:-; locality :1rca somcwh:t t poro11~, 1,'~!1 t· . olorcd lun?st or1 r , .iOn 0'11 and firw ~rn in eel. One or t_wo fr:tgnwnts o{ fosstls from tlus loca lity still indieate the cretaceous pe~1~d; b11t the nhscu.cc of an ~ per{i~ct sp?eitHC rls ruu,·t deter a positive opmL~II 1~pn11 the prec1sc ll~·e. o( tile fornrnt1011. 011c spcci nw11, however ~rom 1ts form, marlc111gs, and fibrous ~truc tnrc, 1 !rave referred to tile gcun~ u1oc ramu ~. It i · ~vidcnt, fron: tire fac ts. presen ted, ~hat. little o( important gcolo~ical change ts obse rved w tr~wc llm g over th1s dtstat lCC of 7 decrn'CS of lonnj. tu~e. . B;lt. at wll:1t depths h t.rc:u h 1.11? s11 rf~1ce ~he conn try i~ 1111dcrlaid by this fot Uld tlOil' liJ ,l ve 110 data {or ucetcl I II ~ . Its II}) pf)rtauce, however, IIlli t not be ovcrloolwd. A calcareo us fonn:ttiotl of thi.- nxtcnt is of' the grr~lc t adv_antag to a <~o nntry; und tire cror1oruiral fr1cilitics il cllcc afl'orJccl in agncultnre, and the u cs of civi lized lifi•, canno t be overstat ed. The wltole fornwtion of. this rcgi~)ll i~ probably, with some varia tions, an_ exte1_1s1on of I hat wluch prevails through Louisiana, Arkunsas, and 1\'hssonn. The st~·ata at ~he locality last mentioned arc represented a~ being vcrti· cal, standtwr agalll t the eastern slope of the Rocky mou11ta in -.:, imtncdiatcly belo\v Pike's Peale Louq-ittrdc 106° , latitude 4.1 °.-At this point, ;tlthotJ~·h ou ly one degree west of the last-named specimens, we find a total chan ne in th rtcology of the regio11. The SJ?~cirncm; arc of a reel Celdspa thic g~·anit e, .. hgwing a lendenc~ to d eco mp~s ttwn; and, from the infornmtion accompn.Jlying t11e same, tlus ro?l~ over~ICs a ma s of silllilar granite, i11 more adv~tllccd stages of dccomposttton. Pile specimens prcsout nothing peculiar in their ap· pearance; a11d the only apparent difl'e rcuce between tiJCse atlcl tire ordinary r~d feldspn.thic granites of more ast ' rtl local iti ns, i~ their fiu cr l)rain and dmgy color. Long:itudc 107°, l~titude .4 11°.-Tlrc specimens from thi locali ty arc of crystallmc feldspathrc gramtc, of a fl es h-reel colo r, apparently 110t acted on by t~c :vcathcr, a11<l presenting tire corHmon appearauce of this kind of gramtc m other localities. No. 9.5, "above the third bed of coal in tire lower !rill North fork of the Platte r ~ve' t·, " 1·R a st· 1·t cco us clay .slilt(!, h'a vr1· 1g a saline tas't e. ~ong1tud c 11?0 , lat itude 41~ 0 ; No$. 99 and 104.- No. 99 is n fine· gralne?, soft, argrllaceon:'l limestonr, of n ligl1 t ash <"'Oior, vidently a modern fo rmatton; bnr, from the absence of fos ils it wonld be ummtisfi1cto ry to 297 [ 174 ] assian it any place in the. scale o_f formations . Tho other specimen, No. 104 ~'is a compact s~rpen~u~e, ha v 1ng_ the aspe~· t of a. grceust.one trap; ~nd, f ' the account gtvcn, IS prohahl y wter::;trn.tdieu wtth the IImestoue. rho /0~stonc is more friable and chal ky than any "pecimen pr )viously troticecl. 1mLongitnde 110! 0 , l<:tti tnde 11~ 0.-Th e pccimens from this local ity arc ry peculiar nnd rcmarkahlr . The first is a friahlc or pnlvcrnlent green ~:lcarcoussand, uuctuous to the to~lch, but ~·ct~w.ining unaltered ou exposure 10 tho atmosphere. Its ch.aracter IS very stnlllar to the g ree t~ sat~ds or ~~nv Jersey; but it is of a. bi.·Lghter colo.r~ and less ~ltarge_d w1U~ tro.n .. l he econd specim n is of sun.llar co J~1p os1.t 1011, but q tllle ·olrd-IJc rng, 1 ~1 fact a green linwstonc. The swg ulanty c f the spccuu n, all(l that wh1ch fLrsl attracted my attention, wns tile efllorcscence of' a salt npou its urfacc, which appears to be, in part, ch loride of' sodinm. Suppo ing tlri:-; to be acciden tal I broke a spccin1Cn, anJ, after a day or two, a similar efiiorc c<'llCO appenr~d from the fresh fractnt~c ;. leaving no ~onb.t but the salt· arise f'rom decomposition of snbs.tances wttl1111 tllo ~to~IC 1 tsc~f; . . Lou(l'itnclc 111°, lalltncle 41 ~ 0 ; Nltu!c~t; rzver.- l hcsc spectmcns [l l' ol a vellowiEih-rrray oo li tic limestone, colltairJing turuo, ccrithi um, &c. The rock is a p~ rfect oolite; and, botl1 in color aud texture, can scarcely he distinguishcJ from pccimens o.r. th Bath oolite . OtlO or the Sf>E'Cim _us. is quite cryslall iue, and the oolt ttc ~t ru c:t ure somewb~t. obsenre. In t lu~ .In-tance, the few fos ils observed cern Jwrdly :mflJctcnt to draw a dccrsrvc concln ion rcga rd i11g the age of the formation; l>nt, when taken in <.:on rwxion with 1he ooliric structure of' tile ma~~, it~ correspondence with tile English oolites, and the modern aspect o(' the whole, there remains less doubt ofthu proprioty of referring it to the oolitic pcriou. A f111t l~cr c<?ll.,<'ti_on from tlti iulcrcstiug locality wonld <loubtlc. ~ dove lop a scnes of 1os~ds which wonld forever settle the question of' the relative age of the fonn a tt.o.n. A few miles up tbi~ stream, Captai11 Fremont ha ·collected a bcautttul ,aries of specimcus of fost>il ferns. Tbe rock is an indurated clay, wholly destitute of !'a rbonatc of lime, a11d wo1.tld b termed a "fire clay." T he e are probaGly, grologically as well as g ographically, hi ol.lCr. than tlr_c oo~ite . pecimcns as the rocks at this place were observed to tl1p 111 the dtr?ct1on of N. 65° W. at an augle of 20 d grces. T'hi would sho w, con~lus t vely, lha~ the vegetable remains occupy a hiO'her position thau the ooltte. A_s,. octatcd with these vegetable remains, were fo und several beds of coal, dtifering in thickness. The section of st rata a t tl1is place is as follows: fl. l1l· andstoue - l 0 Coal 1 ,., " Coal l 3 Indurated clay, with vegcta blc rem a ins 20 0 Clay - _ '"' _ - 5 0 Coal Clay 5 0 Coal Clay Coal 5 0 . The stratnm conraiuing the fo ~il ferns is abont .20 feet thick; and above ll are two beds of coal e~tch about 1 5 inches. These arc succeeded by a ' jo |