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 From the 
 
 Proceedings of the Anirvican Associiitioii for tlic Ailvaucemeul ol Science, 
 rortliinil Jleeliug, August, i'iT.i. 
 
 
 On the Relations of the Niagara and Lower IIelp^rbero 
 
 FOUMATIONS, AND THEIR GeOCRAI'IIICAL iJlSTHIMfriON IN 
 
 THE United States and Canada. By James'IIall, of 
 
 Albany, N. Y. 
 
 In proceeding to the discussion of this subject, I propose in 
 
 the first place to cite a paper read bj' Mr. A. II. Wortlieu at the 
 
 Troy Meeting of the American Association, and published in tlie 
 
 Proceedings under the following title : 
 
 '■'■ Itemarks on the lidative Aye of the Niagara and so-called 
 Lov:er Helderberg Oroups^ By A. II. Worthen, of Sprhifjjield^ 
 Illinois." 
 
 " Recent investigations have developed certain facts, bearing 
 upon the question of the relative age of the above named groups, 
 
 (321) 
 
 •^1 
 
 <: 
 
 ~ #*a.- '. ma g 'a;4a»,. - 
 
C^Bf^3 
 
 v.. NAT! 1!.U. HI-TOr.Y. 
 
 '7 
 
 wliicli we (li'-iro to iircsoiil in m Inicf iiiiiinu r fur tlu' coiisidoraliou 
 of thnsc wlio nrc especially iiileresleil in strntiiirnpiiieiil ii'colojry.^ 
 
 In nnrtliern iuul weNteiii Illinois. I'loni the nioulii of llie Ulinoi.s 
 IJivLT nortliwMiii lo tlie Wiseonsin line, the V\>\)cv Silniiiin divis- 
 ion of the i);ilieo/.oie series is represented liy l>nll', gray, ov yellow- 
 ish-urav dolomites, souiellnies in remarkably oven beds, as at 
 Joliet, and (oatton; and at other localities by eoneretionary 
 masses, with but I'aint traces of stratilicalion. as at Ibidjicport, 
 near Chie:i<.n). and at Tort lUron and Leclare, at the head of the 
 Upper Kapids on the Mississippi IJiver. They ran^io in thickness, 
 from seventy-live to three hnndred feet, and directly overlie tho 
 fihales and arizillaceons limestones of the Cincinnati uronp of the 
 Lower Silnrian si'ries. 'I'hese dolomites are (|iiite fossil iferons, 
 and allbrd many iharacteristic Xia;j,ara species, among which wo 
 may mention J'l-iifKiiirrn.-i (ililnniin^. Spirij'cr i-m^inlns, ('(ihiiitviu; 
 Jili'iiiiciib'tcliii, Ciir'/iifi-iiDis nnmhifi, (JrllKffnin u mini a hi m, ete. 
 From the I'ridLTcport locality alone, nearly oni' hnndred si^'cics of 
 fossils have been ennmerated. a large nnniber of which are specif- 
 ically identical with those found in the Xiai:ara bi'ds of New 
 York and Canada; and. so tar as we are aware, all Western geol- 
 ogists are agreed in considering these dolomites to V)o the strati- 
 "raphical ei|uivalen1s of the Xiagaia group of New York. 
 
 In southern Illinois we tind these dolomites replaced i)y a series 
 of silicions and argillaceous limestones, forming a group two 
 hnmbed and lifty feel or more in thickness, which, like the dolo- 
 mites of northern Illinois, rest directly \ipon the Cinoinniiti group, 
 and are immediately succeeded by Devonian strata. At the base 
 of this group of silicions limestones there are some reddish mot- 
 tled bods, from ten to twenty feet in thickness, that in color bear 
 considerable res<'ml)lanco to the Medina sandstone of New York; 
 and these mottled limestones pass gradmdly into the butf and 
 gray silicions beds that ccnistitute the upper and main p(ntiou of 
 The group. Fossils are rare in the lower portion of the group 
 horel but the mottled limestones contain some Orthnci'nitites, 
 and joints of large CrinuidfiU while the middle and ui)per por- 
 tions are locally (juile fossiliferoiis, and have atlbrded many of the 
 characteristic siiecies of the so-called Lower Ilelderberg groui), 
 among which are the following: Or/his siihrdrhintd. (>. oblatu, 
 Cii-lns'pira siihriiriiKita, C. imbricata, Sj)iriJ'(rr i^er-bnneHoi^iifi, and 
 ri((l>icc'ms fipinile of Hall, and ^lrl<}(isii!>i laimatus of Com-ad, 
 together with species closely resembling, if not identical with, 
 3l7'rista prinrrjiK, I'luliicerux' p>jnniudalaia, P. unfjuljhnne, P. in- 
 die, and P. muUixtriatum of Hall. 
 
 In the first volume of the -Kcport on the Geological Survey of 
 Illinois,' these silicions limestones of the southern portion of the 
 state, and the dolomites of northern Illinois, were regarded as 
 tho stratigrapliical e(iuivalents of the Niagara group, and were in- 
 cluded together as representing a single division of the Upper 
 
 *i 
 
1^ 
 
 II. xATiitAi, ntsToin'. •'-•' 
 
 Silurian scnics ; luit, .nl.M.,,ii.'ntly. in a corrcclo.l section ..f Hi.' 
 Illinois stnitii. iiMbiishcl in ihc IntnMlnction to tlif sccoiwl \ni- 
 unu" wi- were indnrcK IVoni the .lissiinihirily of llic lo^ils Ironi 
 tlic dilfcMTnt sections oi- the state, to rc-anl the silicions Inne- 
 stones of s,.nthcin Illinois as the representatives ol a hiiih.T '^m- 
 lo<.-ical horizon, an.l theivlore |.iace.l llieni alx.ve the .lohnnites ,, 
 the noithein part of the Stat.', as the c,|nivalents of the so-calU'. 
 Lower Uehl'Tl.ero- oronp. We are now. however, fnliy sati>hi'cl 
 from .1 fnnlK'r examination of tiiese Ipper Siiurnin strata, over a 
 more extended r.'uion. that our lirst c(uiclusion was correct, and 
 that these silicions limestones ;ind dolomites represenl tne .^anie 
 ..•,M.lo.d<'al hori/on. and that the dillerence in the sp.>cii:c char- 
 Mcler of their fossil cont.'nts is entirely due to the chanuvs in the 
 oceanic <.on.li;ions under which they were deposited, and not to 
 the dilferent a"es of the sediments themselves. 
 
 South of the Ohio iJiver. t!ie>e Tpper Silurian strata are lound 
 well exposed in 'I\uness..e. in the counties of Wayne. I'eiry and 
 Decjijur. on the 'reunessec Kiver. outcroppin;i- over a wide area 
 and allbnlinL? numerous species of fossils in a line st:.le ol preser- 
 vation. The base of the iiroup here consists of reddish and mot- 
 tled limestones, verv similar to those in southern Illinois, and 
 contain Orlhnrrras mubihilnm. and Joints of lar-e crinoids m -ireat_ 
 abundance. These red limestones are sncceed.'d by a series .,1 
 orecnish-.-niv shales, ami slialy ar-illaceous limestones, contain- 
 
 mJni^ l'liHr">-«'< Si'i<l<n-rus,-. rmtoan-rNs nl,lni,,i„s, Orllns h;lhriiUu 
 ,-h"rn^tnh,, etc., associated with siich Lower Ileldcrbei-i- lorms 
 ■IS ri'iit^imcnis <i<i}<'„htx. Splrifi-r jU'r-litmcllnsns: S. „i,iri;,,,l,'>n;,. 
 Mnrist<( Id'ris. ]{l,'i,i<'h<u„'lhi reulriros».-<, and many others, showimz' 
 that the fossils of these so-called >ir()Ui)s are lu'iv iiitermin.-iln 
 thromdi the same strata, conlirmin-- what we had already assumed 
 to be true in Illinois, that the Ipper Silurian beds ol the U c-t 
 constitute but a sinole -iroup. and consc.iiiently that the term 
 Lower Ilelderberu. as applied to a -iroup distinct from the >iao- 
 .ira, is supertlnons. We recollect that, on visitin- the locality o| 
 these so-called Lower Ilelderberp; limestones in the Schoharie 
 vallev some years aoo. we obseived these limestones resting- im- 
 mediately upon nud'isputed Lower Silurian beds there, and, in 
 explanation of their occnrronce in this apiiarent abnormal posi- 
 tion, we were told that the Niagara -roup was supposed to have 
 thinned out to the eastward, and that these Lower 1 elderbeii;' 
 limestones took tl'cir place, lint is it not .luite as probable that 
 there has only b-en a change in the litholo.uieal chair-ter ot the 
 beds in their' eastern exteusi.)n in New York. resiillin«i- there, as 
 in Illinois, in a decided change in the specilie character ol the 
 fossils which they contain, ami that the Upper Silurian beds at 
 Schoharie are the exact eciuivalents of the Niagar.i shales ami 
 limestones in the western part of the State .'' 
 
 -ms^m-Es^PSPSnTT' 
 
 „fj.i,i.jff3-r^--~Sm*i ".-jJ<Sa»E»*» . i-Mnfiini^"---id 
 
 4 
 
 .1 
 
:V.U 
 
 II. NATIKAl. Il'STOItV. 
 
 To ruc'iipiliilato, then, tlic iMcts iis they arc present ril in the 
 "West; wc liiul thnt the (hjU)iiiites of noitlierii lUmois contiun 
 oiilv Ni:i"-iini fossils, and I lie silieioiis liniestoiieH of the soiitliern 
 portion o? liie StMte eontiiin onlv tl- >so eoiisi(h'rea ehiinietenstK', 
 of the l.()>ver llelderl.eru -.nonp ; wliih" tiie l-eds in Tennessee, 
 oecupyiiej; tiiesanie slnitiunipiii.-il position witii tlie (h)loinites iuul 
 llie siiieiJns limestones of Illinois. Inive Ni:i;iMi:i iimi J.ower llel- 
 ,lcn>ei<'' fossils interniinuled iiidiseiimiiiiitely thionjih the strata. 
 Ileiiee'we eoneln.le that the so-ealled Lower Ilehlerherg -rronp 
 has no real existence as a distinet ^n'onp of Upper Silurian strata, 
 and Ihu*. <.he iiai-.o, hein.u siiperlhiniis. should lie dioi.ped lioin the 
 iionieiielatiire of the Ainerieaii roeks." 
 
 It is here proposed, in an article oi" less Ih.an th-'ee pages, to 
 discard entirely from the jr(.ol.,oi(.;d series and gcolo-rical iioineii- 
 clature a well reeo-iiiized j-roup of strata : well Unown a. id clearly 
 delined for more than one iliousan<l miles in extent of country, 
 spreadiiii-- .liajioiially over nearly or (piite lifleeii de<;rees of lati- 
 tude, while its undr.'ialiiiir and repeated outcroi)s, owing to anti- 
 clinal erosion, add some hundreds of miles more to its known 
 
 (.'.\i)osure8. 
 
 The result of tedious and careful /leld investigations in the 
 work.ng out of hundreds of sections in various parts of the conn- 
 try iK.ve been suppleinente.l hy the study of large collections cf 
 niimevous species of fossils, and the linal comparison of all these 
 foss'.ls, from the far northeast or the St. Lawrence to Tennessee 
 0:1 the southwest — from tiie IMississippi valley on the west, from 
 t'le states of Iowa, Illinois, 'A'isconsin, the Islands of Lake Huron, 
 and Canada West (or Ontario), together with the more critical 
 study of the rocks and fossils within the limits of the state of 
 New York — are all to he set aside, and a simple assertion, un- 
 supported by sections, by fossils, and I may say by a single fact 
 of importance, is to be substituted for all the labors of thirty 
 
 years. 
 
 Thih- assertion comes from a gentleman holding the important 
 and responsible position of State Ceologist of Illinois, whoso, 
 name is associated with so nnicli of the geology r ad paleontology 
 of the West as to give currency, if not authority and authenticity, 
 to what he may say : — and certainly he ought lot, witiiont good 
 reason and authentic data, make such assertions nor put such a 
 paper before the American Association for the Advancement of 
 
 Science. 
 liut will the geologists of the United States accept this so-called 
 
\ 
 
 I 
 
 n. wniiM, iiisroitv, 
 
 825 
 
 (Ictoriniiiation of tlic iili'iitity of tlio <iioiiiis of strMtji known iw 
 llic XiMiAUA and tlic Lowi'.n Hr.i.UKKiiKUd ?* 
 
 I'liil Air. Woillicn is not oriiiinal in tliis vi( w of tin- relations of 
 tlic two iiTonps of strata, lie lias nu'iciy icvivi"! an old ami tlis- 
 canlcd I'lTor. Tlu' same .assertion was lony .1; o niauc in tin- (ii'o- 
 logieal IJcports of rennsylvani.n and else viieic ; and was .at oiu> 
 time tlie <»iMUTaily accepted Itciici' ainonu' ui'olo.n'ists. I'lol'essor 
 IJo^iors, in a pa|KM- i;)on Niagara Fall- piilili>lu'ii, I lifiiivc, in 
 is.".-.', takes tills view of the relations o! tlu'se forinati(»ns, ami in- 
 elndes also the limestone of Ulaek IJoek nmler the same desiii- 
 nntion. It is not smprisln^ tliat at that period, when no eiitical 
 pxaniinalions had leen made, when we Iiad no knowleiliic of |)ale- 
 oiitolouT as a iiiihle In the more oitsenre .and dilliiaill poinl>. that 
 yrreat snrfaee features should have lieeii taken as jinides in the 
 (lotcrminatlou of ucoloirieal formations. It happened in thi-^ <'ase 
 that the <i;reat eseariiment of the Niagara at Kewiston ae.il (^>ueens- 
 town was reganled as the e\teiis;,:i! of that of the I lelderlieri^ 
 and tho south sl(U> of llie Moiiawk valley. 'I'he limestone of 
 Black Ivoek. though so far sepaiated from Niagiua. was regarded 
 as a part of the same : the features in iheWi'sl ijeing more suh- 
 dued, as was supposecl. 
 
 This in lirief was the eondition of our knowleclgc and lielief 
 regarding these formations at the lieginning of the New York 
 Geological Survey, and Co)' some time afterward. 
 
 Tlie one horiz(Mi which aliove all others was at lliat tinie re- 
 garded as fixed Iveyond (piestion was that (,il" 'he salt-lieaiing 
 strata. This formation, at its base hearing .a gre.at thickness of 
 red and mottled shales and marls, succeeded I>y gray, ash or drab 
 coIohmI hods of similar dnractors. and limdly hard beds of linK!- 
 fstono, was regarded as clearly delined Irom Saltspringville in the 
 iMohawk valley, hy way of Syracuse, .Montezuma, anil thence 
 ^vestward along the base of the Limestone Terrace from Uoches'.cr 
 to Lowiston. 
 
 Throughout this entire extent smU springs had boon discovered, 
 and brines of varying and <lillerent (pialitie.s were known to exist. 
 Ko doubt of the nature, age. or identity of the formation, from. 
 
 *01' liito years, ill cfitiiin (lUiirtois. it lias Ijccii mily lu'cosaiy lo cdMiadii't "hat 
 lias bi'cii (Imu' in llic Slali; iil' New \(irk. or by iinsmis in lii'r employ, boUi in f;eo|of;y 
 luiil paleoiilolo^ry, ti) have the slaleiiieiit aeee|ileil on liare as>erlioii. I mifllit iii>tan<e 
 examples too numerous (■) lie creditable to the aeiinieii ami fiooil sense, to say iioihin^' 
 of the scieiitille ability, or those who pidiio>e or neccpt such conclusions. 
 
 fr 
 
f 
 
 f 
 
 32G 
 
 n. 
 
 N.VTIWAI. IlISTdUY. 
 
 II.ikiiiHTroniily I.. Ilic \i;i-;un liiv.TJit Lcwistoii. liinl cvfr liPOll 
 ,.Npiv.s..,l. (,r. s(. r.'ir MS I knew. fnl.TtaiiiiMl l.y i.ny one. Now, 
 tluMi-li llii^ iiiiiy seem invli'vimt t.. tlif (|iifstinii tu'lorc us, it 
 ucvortli.'lcss lies" :it tlic lntiii.l:it ion of tlif I'lror llicii pivviiiciit, 
 ictiMnlin- til.' Nin-niM uiul llrl,|..il.rr- lonnMlioiis ; iind is iiiti- 
 lUMtcly roniu-i'tnl witi. tlic -ivairr cnnr i..)w soi.-iil 1.. Ik- ivviw.l 
 ill liii' piipiT iimliT (■uiisidiTiition. 
 
 Jt was not iiMtil tlu' dosi- of llu' li.'i.l w..ik of l^-^ tiiat ll.is 
 ,,ursti(.n came \>vi\>vv ilw a-s,'iiii>|.',l miciiiIkts coiistitnlinM; tin; 
 (ominissicii of tiif New V..ik ( Ifolonical Survey. Tlic y...m-v>,t 
 uwrnU'V ..r ll.al Ixnly iia.l asMTlcd, as llu. icsiiH ..f liis iiivc-stig-a- 
 ti,.i.s. tliat tlu' rocks at tlir ha>.' ol' tlu' Ma^r:.,a TciiaiN-, coiisist- 
 iiiii- u{' vi'i\, -ray and inotll.Mi marls and saiid^t -„.'s, w.tc not Uie 
 (•(m!iiinati..n oi" tlic salt l.carinii' lu-ls of Onondaga, an.l .■iM.wlicre 
 to tlic eastward. I.ut a lower foniiatin,, : lliat llie Nia^^ara lime- 
 stone, so lai.uely .level. -lied at Nia-ara an.l L.-.^kpoil. was not ii 
 cmtinmitiou' of' tlie linu-stoiie of lla' IleMeihero-. l.iil a dislinet 
 f..rination : liaviiij-- its e;ivatesl devel..iini.'nt t..war.ls tlie west, and 
 oradnaliv tliinniie^ to the eastwanl : an.l that inst.^a.l of lyiiifl 
 ahove the Sail loniKiti..n it lay l.eneath it : that the Salt lovma- 
 tion. e\ien.liim- westwanl IVoiii Syiaeiis.-. passe.l to the soiitliwanl 
 of th<- Niagara Terrace, an.l I'onue.l the lin.a.l belt of Hat eonntry 
 to the south o{ th." raii-v. wliieli is so marke.l a feature fr.)iii the 
 (u'uesec Hivi'r south of Uuchcsler to the Xiauara Wiver at Tone- 
 wan.la : tiius separatin;:-. i.y a .listaiiee of several miles, the lime- 
 stone of Niauara and that of Ulaek Hock. 
 
 Til.' con.litions which ori-iiially h'd to this misapprehension of 
 the relations of the ditlerent formations, are, the flat marshy conn- 
 try from the outlets of S.-iieca an.l C'ayui-a lakes to tin- n.^rthward, 
 Avhi.'h has obscured the outcn.ps. and beyond this, in Wayne 
 e.xinty. the -reat a.vumulati.)!! ..f .Irift. which has .leeply eovered 
 the n'..'k over a h:r-e area. If to tlu'se we add, that in the ear- 
 lier iie..l.)i..ieal explorations th.' line of the Krie canal was that 
 principally travellc.l. — that the passa.ire from the rc.l an.l gray 
 marls of th.' Oiiomla-a iv.^ion t.) the red an.l mottled marls of 
 the Medina San.lstone at H.n'hestcr and westward of the CJeiiesec 
 Hiver was thron-h an alluvial or .Irill eonntry which concealed 
 1h.' nnilerlyinn- ro.'k lormations. — the supposed identification of 
 th.' two formati.ms is not sui'prisinij.-. 
 
 That such views shouM i)rcvail before contimied and connected 
 
 f 
 
f 
 
 r 
 
 i 
 
 n, NATi i!Ai, ni-ri>i!v. •>-< 
 
 ()l)'^l•^V!lti^)n^ liMil Iti'fii ciuiii'.l tin. we nn- prciuirt'il to mnliTstMiiil ; 
 Imt nlltT iicfirlv lorty yoars of oliscrvntioii. iiinl mIIci' IIic ii'Im- 
 tioiiH of ill! tli('s(> rock'* liiivc lu'cii I'lilly imdcrsioiMl I'm' thirty vt'Mi's 
 or iiKMi'. 1 ^llllmit tliiit it is in>t wurtliy of tlic crcilit of tlir Aiiicr- 
 ic.'Ui ANSoci;itioii to iillow siicli ;i |p:iii('I' to psiss into its pnlilicti- 
 lions wiliioiit sciioiis consiiliMiition. I'crsoiiiilly I niiiy lie intcr- 
 I'stcil ill this ([lu'stion iiioii' tJKin otiici's. sincr I Iimvc |inlili-iicii :i 
 voinnir iiiinri|i:ii!y iijion tin- |);ilcoiiloloL:y ol" lli>' foiniMtioii or 
 jii'oiip liiTc proposed ;u he (lisi':inlf(| !is liMvih'j; no scpiirati' or dis- 
 lini't existence in tiic series; lint tlic scienci' of i;'eolo;j:y. find 
 tlio^e wild pui>iie tli.il X'ielire. lliive Mli inlei'e>l ill tliis (|ilestioii 
 f;ir superior to cue of liu'ic liersolKliity. 
 
 (unlnijicill i-rlillliiiis Hull ijc^ 'ij/'i j'/i irdi ixicii.iidit (if Ihr ijronpS ill 
 IlKI'fitiiill. 
 
 StMilinu from llie typieii! loeidity of liie \i;iL;:ir;i uroiip. where 
 we liJlve of tile sli;de and limestone ;i tliielxliess of sometlliiej,' more 
 tli.'in two Imndred feet, .'ind tmeiiej, the oiit(ro|) in an easterly direc- 
 tion, we lind a very ;^radiial Imt pretty constant thiiininii' <>f the 
 beds of the formation, so that at a point one iiniidred miles easl 
 of the Niai^ara IJiver, it has a thickness of scarcely oii(> Imiidreil 
 feet. l''ailher cast . in Oneida eoiiiity, the formation is still thin- 
 ner, and in >oiiie places lias ]iec(jiiu' in \y.\\\ or almost entirely :i 
 l)recciate(l and concretionary mass, with few or no fos.sils.* 
 
 (ioiim; eastwanl it liecomes still fnither atteimated. Imt can 
 still lie traced holh in its physical aspect .'uid outcrop, ami by its 
 fossil conU'iits. In the neij^hlioihood of Schoharie. Cobleskill, 
 C'herrv valley, etc it is known as the Coralline ],iiiic>.tone. from 
 its abiimlaiice of corals. These arc principally identical with tlio 
 corals of the Xiai^ara liroiij) in western Ni'w Yoik ; and most of 
 the species of Ibachiopoda which occur in a condition to be recoff- 
 ni/.eil. are similar or identical witli Niagara forms, while there aro 
 several species quite distinct from those of lli(( Niaji'iira iiioiip in 
 the west. The npi)er limit of //(////s/V^'n cuIciiiiIhIhs. so far a.s 
 known in Xew York, is in the Niagara limestone; and this fossil 
 occurs ill the cornlline liinestonc at Schoharie and at I.itchlield in 
 Herkimer tMMinty. 
 
 1 have given in vol. ii, I'al. N. Y.. p. :121, more at Icii'-tli my 
 
 *In Hint pint (ir llio state llic Coiiniilioii is -.1 iii-ifrnillrMiil, lliiil it \v;is oi-iniiially re- 
 gavili'd liy Mr. Vaiiiixi'in iis 11 Mibiiriliiiiilu incinbiT d' Ihc I'luloiin (ir Clinti'ii frnmii; 
 mill was only ici'ojjrni/.cil Ijy liim !ih a distiiicl IV lalinii in ls;i!i; al'td- tlie iiivustiga- 
 tiuii- in tlio wo-tui'ii counties liad sliown its Inie ri'latious ami iiniioilani'e. 
 
 ^/ 
 
fr~ 
 
 o 
 
 886 
 
 n. NATt ItAt. llI'TOTtY. 
 
 roaHoiis for roRMnlin<i M-* <'>ii.l =n.- limcHtonc n« the cftstcrly oon- 
 timiuticii of til.' Niiij-nm -iroiip ; aii.l siiico tlic tiin.' of tlml iniMi- 
 cntioK, T liiivc iiia.l." niiiiu'i'oiis ol.scrvatioiis iipon the ivlMtiniis <.f 
 tlic coialliii.' lim(wt,.iic, all of wliidi have ti'iidcil to coiilinii tin- 
 views thm- cxiMvsM'.l. Tlii-. cnialliiif liiiu'stoiic in its attenuated 
 form nm.v l)e ree(.fjjnize<l in tlu- vall.-y of tlie lindsun Kiver nii.ler- 
 Ivinij the water-liuie foiination at numerous loealities. 
 
 Now retuinin^f alon^^ this line of onterop to the Niafjam Kiver, 
 jind roih)\vinu- the formation to tlu" northwest, we llnd it expand- 
 in;; in thieUnesH and aiva thion-h Canada West to fai.ot'K Head ;^ 
 aiU)earin^' in the islands alon,n the eastern and northern side of 
 Lake Huron, an-l stretching' aeross the peninsula IVom St. .lo-eph's 
 Hiver to the oiilhM ..f (ireen Bay ; tlu-nee oeeupyin-- th." principal 
 part of the peninsula l.ctwccn ( ireen Hay and i>alve .Michifian, it 
 expands to tin' soulhwanl heyond the southern limits of tliat lake, 
 and thence trends to the we>t and northwol liirouj-h Illim)is and 
 I„wa. From the Nia-iari' IJivcr westward, the formation is chietly 
 a maiinesian limestone, and in nuiny loealities carries an al.iin- 
 dance of fossils; liotli the physical and paleontologieid evidence 
 leave no donht as to the a^^v and relations of the formation. 
 
 Keturnin.Li ajj;ain to the eastward and southward, we find that 
 the anticlinal movement, which elevated the islands in the weste.n 
 part of Lake F.rie. has Lronyht up the Niagara formation in llie 
 udjaeent parts of ( )hio, where it is nmrked hy thi> iiresonce of a 
 p;rcater or h-ss proportion of its characteristic fossils. Hero it 
 Htretches in a h.w axis for miles to the south of the lake, and 
 thence s|)reads and outcrops on either side of the rocks of the 
 Ilu.lson lUver and Trenton a.ue. which form the central or lower 
 visible portion of the Cincinnati axis, 
 
 Followinij; tliis direction it extends through Kentucky and Ten- 
 nessee, everywhere carryini; its characteristic fossils. 
 
 Throuuliont all this extent, until the formaticm reaches Tennes- 
 see, there is no ([uestion raised as to the identity an<l [.urity of 
 the' Niaizara iiioup. Here, it is said that the fossils of the Niag- 
 ara are iTiinLcU'd with those of the Lower Ilelderl.erg uroup. And 
 a'j;ain,ou tlie Mississippi River, in Illinois and Missouri, we are 
 tJld that this mingling- of the fossils of the two periods occurs. 
 
 Bnt before proceeding to discuss this part of the question, let 
 us for a moment give attention to what is termed the Lower 
 Helderberg group in its typical localities. 
 
 /J 
 
 
n. NATlUAr, IIISTOUY. 
 
 n2!) 
 
 >ily con- 
 it imldi- 
 
 itinlis of 
 
 linn till! 
 Icnimti'd 
 ■r iiiuliT- 
 
 •tt llivor, 
 
 I'XpMlul- 
 
 'h lli'iul ; 
 11 s'kU' of 
 .lo-i'lili's 
 iniiiciliiil 
 ■lii<i!Ui. it 
 liiil lake, 
 iiiois and 
 is cliictly 
 ill! aliun- 
 ovidcncc 
 ion. 
 
 liiid tlial 
 c west fill 
 on in the 
 I'licc ot' a 
 Hero it 
 lak(>, and 
 ks ()(' the 
 or lower 
 
 and Ten- 
 's Tennos- 
 
 imrity of 
 
 the Niag- 
 )np. And 
 iri, we are 
 
 occurs, 
 lestion, let 
 ihe Lower 
 
 /J 
 
 Tn the Ilelderhovi Mountains in AH-aiiy oonnly, and in Scho- 
 harie aloii'i the valley of the Schohari.' Creek, and in the {'..l.leM-^ 
 kill valley, we lind everywhere a scrirs or jironp of liniotnnes, of 
 which w('.listinetly reco},Miize four nienihers ; these are known, in 
 the asc( ndinii order, as 'rcntacnlite limestone. Lower I'entaincnis 
 limestone, Shaly limestone and Tpper rentanierns or Scntella 
 llmeHtone. ■riicre is in sum.- places for miles in extent a mass 
 of Stromatop<.ra limestone hetwc.n the 'rcntacnlite ami Lower 
 I'cnfamcnis |imest(.ncs. ThcM. L.-vtlicr con-litnte the Lower Ilchl- 
 cri.er;; j>roup. formiie,' in Alhany county the has.- of Ihe Ilclder- 
 ber},' mountains, and cxvrywhcre succeeded hy the Orisk.any sand- 
 Htom", Canda-alli and Schoharie nrjt i.nd Corniferons limestone,^ 
 and these, in the summits of the hills l.y the arenaceous shales of 
 the Iliimilton uroiip. 
 
 This ^rronj) of limestones is everywiiere characterized l«y the 
 presence of fossils, often in innncnsc nnmhers. and spccilically, 
 with very few exceptions, (piite unlike the los>ils of the ro.'ks 
 above or'l.elow this horizon. I'roni the llcldcrhci-s, and tiic val- 
 ley of the Schoharie, we are able to trace the formation to the 
 westward thron-h ihe northern part of ( )tsc<;o, and the southern 
 part of Ucrkinier and Oneida counties; and, accordin-; to Mr. 
 Vaniixem, it is recojiuized in the eastem part of Onondajia coun- 
 ty, by the presence of some of its peculiar fossils. From the 
 Hehlerberii mounlains the <;r,,up orMdually thins to the westward; 
 and in Herkimer county the divisions of the several members are 
 scarcely rcco<>nized. the entire mass becoming,' more completely 
 calcareous but still char<j;ed with an abundance of the character- 
 istic fossils of the group. West of ( )nonda-a county the i.lace of 
 tlie formation is often recognized by a stratum of hard, compact 
 limestone lying beneath the ( )riskany sandstone.* It is .luite evi- 
 dent that the force of the entire groui) diminishes in a westerly 
 
 direction. 
 
 Keturning to the point of departure in the Ilelderbergs, wo arc 
 able to tracH" the rocks of this group, in their clearly defined aud 
 unmistakable characters, through the eastern counties of Now 
 York to t!ie limits of the state of New Jersey. In the north- 
 west part of that state the formation has been distinctly recog- 
 nized by rrofessor Cook. The same has been fully described 
 
 *In '^(.ine fonm.,' Ucimrts on tlie (;..ol„Ky of Uk' wcston, .•ountics. tliis rook is do- 
 scribca as «oni or croauil pruvious to tliu aei>o.iliou of Ihu Oribkaiiy saiul-tone. 
 
 A 
 
M^ 
 
 \ \ 
 
 I 
 
 830 
 
 15. NATIltAI, llISrOUY. 
 
 as tlio "T.iniostono foiiiiatioii, No. vi" in tlio <;('f)l()gk'iil siir\oy 
 of I'eiiiisvlviiiiia, wlicrc it iiijpc'ars in nunii'iouN outtTop.s, and 
 oxlcnds tliencu tlirougli the woslL'rn part of ^Maryland and tlu'ongli 
 Virii'inia, alonu' tiu' Appalaciiian rango into Tennossoi'. 
 
 >»'()\vlicri' tlirongiiont tills extent of country, a.s far as \'irgini!;, 
 lias any one sliown. or attempted to sliow, tlie mingling of lo\iei' 
 Heidelberg .•md Niagara forms among the fossils. In the large 
 c(jl!ections whieli 1 possess from Maryland and N'irginia. I have 
 never observed the least evidence of such mingling; and in ^Mtny- 
 laiid and the adjacent parts t)f >'iigiiiia I can speak from i)i'rsonal 
 olisi>r\ation that the formation is as well di'liiied physicall}- as in 
 any pait of New Y(jrU. 
 
 J-i't ns now look to tiie northeast, wliere the geological survey 
 of Canada has traced the lower lielderberg formation from ]\Ion- 
 treal to (iaspe. Having examined targe collections of these 
 l')ssils from the (iasjie region, and oUh'I's from \w.\x Montreal, 
 1 have never seen the least indication of a mingling of any other 
 forms with those characteristic of the lower llelderbeig. 
 
 "We have uow' traced this formation from tiie forty-third par- 
 allel in the state of New York to about the thirty-lifth parallel 
 of latitude in Ti'iinessec, and over liie greiiter part of this extent 
 Ave have no knowledge of a mingling of the fossils of the two 
 groups or formations. Again, from the vicinity of jMontr?al to 
 Gaspe, a distance of some seven hundred miles, the formation 
 ■wherever know,' carries its characteristic fossils. 
 
 This gi-ou)) is likewise recognized in the state of Elaine, where 
 it is characterized by minierous well known fossils ; and it is not 
 improbable that it may be e(iually so in the eastern townships of 
 Canada anil iu the belt of limestones extending through \'ermont 
 to the northern part of IMassachnsetts. 
 
 Having thus hastily sketched the ground occupied by these two 
 groups of strata, wo may now consider their relations to each 
 other. a\!d the evidence of the mingling of the fossils which 
 wonld render it necessaiy to relieve the nomenclatnre of geology 
 of one of these names, heretofore adopted, and in general use 
 wlicrcver geology is written or spoken. 
 
 I will here cite a single sentence from the paper referred to: — 
 
 "We recollect that, on Aisiting the locality of these so-called 
 lower lielderberg limestones in the Schoharii' valley some years ago, 
 Ave observed these limestones resting immediately upon undisputed 
 
 if 
 
 \ 
 
 >^ 
 
 ^-.a - i ,<> - «. > . , . . 
 
 ■MiMf ««aM» - 
 
n. NATIi;.Vl. 1II>T(IKV. 
 
 O "I 1 
 
 V 
 
 >N 
 
 !l 
 
 luwcr Siliirinu IhmIs IIutc : iiml. in cxiilMiiiitioii of tlicir occiirroiirc 
 1 tliis iipiiiirt'Dt !i1mi()1iii;i1 iiosilioii, we wcri' toM UkiI tlic Xiniiiiiii 
 •Al'oill) was sil|")()>C(l to Ikivi' tliilllUHl out to tlic f:i>t\v;U(l, iUlil 
 timt tlu'sc lov •■ Ilcldcrlii'iii,- liiiu'stdiics took tlii'if i)l;ic('." 
 
 Furtuiiatcly or iiiifortmiatcly tlicrc is no cviilciicc i:ivi'!i as to 
 the aiitlioiity or ii.v wliom " irr n-m- Inhl" tliat tl:o Nia<iar!i <ir,,iip 
 liad thimuMl out to tlu' eastward. In tiic liisl plac-c lot us in(|uiro 
 a^ to tlu' liR't of the lower lleiderberji' ••limestones nstinii: inune- 
 diately npon undisputed lower Silurian lieds tiiere" or elsewliere. 
 Having; lieen laniiiiar with the Selioharie valley, and iiavino; niaile 
 numerous seetions. and explored lonu: lines of outcrop in that 
 valley, in the lohleskill valley and in the Ilelderlier^i'. I have 
 never been ahle to see the lower Ilehlerlierii' limestones resting 
 npon lower Silurian rocks. On the contrary, the section ol' stiata 
 everywhere shown is the following, as given on the diagram, from 
 t!ie sandstones ol" the Hudson IJiver grouii to the Ori-kauy sand- 
 stone : — 
 
 Oriskany sandstone. 
 
 r I'ppcr I'eutanieius limestone. 
 Lower Helderlierg j Shaly limestone. 
 
 \ Lower rentamerus limestone. 
 } Teiitaculito limestone. 
 
 group. 
 
 AVater-linie forination. 
 Miagi'ra gi'oup = Coralline limestone. 
 
 Lower Silurian 
 
 (ireen shales with Iron i)yrites. 
 j Sandstones and shales of the Hudson 
 ( River group. 
 
 Everywhere the lower memlier of the lower Helderherg gi'/up 
 is unmistakably separated from the sandstones of the lower ,'»i;ii- 
 rian a<>e by three distinct and usually well nnirked members of 
 till' series. 
 
 Tracing the lower Hetderberg formation from this point for 
 sixty uiiles westward, we have the following section : — 
 
 Oriskany sandstone. 
 Lower Hclderberg (* Shaly and lower I'eutamerus limestones, 
 group. i 'reutacnlitc limestone. 
 
 *Tlio luiiifv l'ciitai)icni~ limestone i^ not ilcvL'ldiKMl ;i> a Ui.-tiiK't iiieiri1n.i- uf tlie 
 
 groui). 
 
V 
 
 332 
 
 n. NATinAL IIISTOIiV. 
 
 AVator-liuu' fonnatioii. 
 Onomlaji-ii salt uroup^Ked uiid gray marls. 
 
 Niaii'ara <;-r<)iip=Coralliiio liiiicstoiio. 
 
 r Gi'cfii shales and sandstones with oalca- 
 C'lint<Mi gi'oiip:= { rt'ons hands i-ontaininy inliTstraliliccl 
 
 1 beds of rod lumatitc. 
 
 Medina sandstone. 
 Lower Silurian = Ci ray and bluish-gray sandstones and 
 
 shales of the Hudson Rivor group. 
 
 Everywhere the lower nuMnber of the lower Helderberg group 
 rests upon the wat- r-linie formation; and tue latter is always 
 present, separating the former from the coralline or Niagara 
 limestone. At a distance less than one hundred miles farther 
 west, in a line from Seneea or Ontario to Oswego county, we 
 have a sectiwn showing the following formations ; — 
 
 Oriskany sandstone. 
 Lower Helderberg group ( Compact grayish-bliio limestones in a 
 represented by { band of a few feet in thickness. 
 
 Water-lime formation. 
 
 Onondaga salt group with salt springs 
 
 and gypsum beds, more than 1,0(10 
 
 feet in tiiickness. 
 Niagara group. 
 Clinton group. 
 ^Medina sandstone. 
 Hudson Hiver group. 
 
 At this point the Niagara group is separated from the contin- 
 uation of the lower Helderl)erg group by strata of more than 
 1,000 feet in thickness. 
 
 Everywhere throughout New York the lower Helderberg group 
 is underlaid by the water-lime formation : and the same is true in 
 New Jersey, rennsylvania, Maryland and Virginia; and every- 
 where throughout New York and Canada West, and in AVisconsiu 
 and Iowa the water-lime fornuition lies above the Niagara group, 
 
 /\ 
 
•«<trp ■»*:"*'? 
 
 It. NATIHAI- IlISTOKY. 
 
 333 
 
 A 
 
 or its rcpresontativo, tlio conilline linu'slono.* In lu. c:.so .lo 
 tlii'si- two lormiitions come toj^ellier oxct'i-l wlierc llio watoi'-liiue 
 I'oniuition is iihscut. 
 
 Certiiiiily tiu-sc InniKitions aii" widely cnoii-ili sci)nr:it('il to con- 
 stitiite (listiiu't uroiips over tlie areas iiained. 
 
 It is suggested in tl.e l)ai)er eite.l tl.at tlie .lillerence l.etween tliu 
 fossils of Ihe lower IleUlerherg group in eastern New York, and 
 those of the Niagara groui) in the central and westi'rn part of tlio 
 state, is due to "a change in the lithological character of the lieds 
 in their eastern extension." 
 
 In the western l)art of the stale, the Niagara group is com- 
 posed of calcareous shales and dolomites. The lower Ilelderl.erg 
 group in the eastern part of the state consists, in its lower part, 
 of thick and thin bedded dark or black limestones, wilii shaly 
 partin.rs, and sometimes with thicker intercalated shaly layers ; to 
 these succeed the heavy bedded limestone with I'mtami'mx <juU'a- 
 tns, which by the intercalation of shaly matter becomes tiiiu 
 bedded, and passes by almost insensible gradations into the 
 '' Shaly Limestone," and fmally to a silico-calcareons shah'-t 'l"li« 
 hi.d.er member, in many localities, is the thin bedded Upper I'en- 
 tamerns limestone, while at Becraft's mountain and in the Ilelder- 
 ber- the upper member is a heavy-bedded encrinal limestone 
 soiiR'times known as the Scntella limestone, from the presence of 
 great numl)ers of the bases of A.-<i>idocn,tus. The shales of the 
 Niagara group and their contained bands of limestone, which are 
 the most^highly fossiliferous portion of the group in New York, 
 are not dolomitic ; and it seems a most extravagant supposition, 
 that the slight lithological ditferences in the comi)osition of the 
 strata couhrproduce an entire chumje in the fauna ; presuming the 
 deposits to be of the same age. 
 
 We now come to the consideration of the last paragraph of 
 this remarkable paper, in which we have the following summary :— 
 
 "To recapitulate, then, the facts as they are presented in the 
 West- we fmd that the dolomites of Northern Illinois contain only 
 Nia-rara fossils, and the siliceous limestones of the southern i>or- 
 tion"of the State, oidy those considered characteristic of the lower 
 
 *It is true that over a consMoinblo part of tl.o lake r..>;ioi,, llio watci-li.ne an,l 
 Onoi.aaga salt g.-oup have been crcU-l Inm. above the Niagara lor,nalio„UH.,,la.e 
 of U.e.e Borter forn.ations being o..c,>„iea by the lake.. See Fo.ter an.l U hUney'. 
 Report on tlie Lalie Superior I.anai)i>lri(t. 
 
 tThe phy-^ical aspect of thi.s portion of tlic group is pro>scrvea m tlic -siliceous 
 Uinestoim' of this age in the southwest. 
 
334 
 
 n. XATintAL Hlr^T'iKr, 
 
 Ilt'ldorbprjr firoiip ; wliilc tlio licils in 'rciiiiossco. occupyiiiij; tlic 
 Sivino striitiLtrniiliical i)()siti<ni with tlio doldinitcs mikI tiic siliccoiis 
 liincstonos of Illinois, liiuf Niiifj;:ir;i iind lower Ik'ldcrlicr.u fossils 
 minj^lcd indiscriniiniiti'ly tln'on<>li tlie stratii. llont'c wc fonfltido 
 timt'thc so-enlU'd lower lloldertierji lironp luis no real exisUnce 
 as a dislinel linnip of npiuT Silurian strata, and tliat llie name, 
 boinji snperllnuus, slionld lie dropped I'roui tliu nonienelatnri! of 
 the American rocks." 
 
 The valnc of this conclusion will ho best appreciated from the 
 fact that in southern Illinois and adjacent parts of ^Missouri 
 the limestones holdin>,f the characteri-^tic Nia<iara fossils lie be- 
 neath those containing the characteristic lower 1 Ielderber<>- fossils ; 
 and that we iwrcr "have Niagara and lower Ilelderberg fossils in- 
 discriminately mingled through the strata ;" unless it be in the 
 debris along the outcrop ; and I assert this from iny own obser- 
 vation. The same is true of the beds in Tennessee; and though 
 the collections of I'ossils made on the outcrops and among the 
 debris do contain fossils of the Niagara and lower Helderberg 
 formations mingled together, this is not true of the rocks /(* situ. 
 In this opinion I do not rest alone ; and it is only necessary to 
 consult the report of Professor Salford to show that he finds both 
 the rocks and Ibssils o." the lower Helderberg formation distinctly 
 separated from, and lying above, those of the Niagara group. 
 
 In some localities Professor Satlbrd asserts that he Ihids fossils 
 of the two formations mingling along the line of contact, which, in 
 the absence of all intervening beds, may very well hai)pen. And 
 this fact, so far from proving the identity or synchronism of the 
 formations, is a very important proof of their distinction in order 
 
 and in time.* 
 
 In reviewing the facts, and considering the known range and 
 extent of the Niagara and lower Helderberg g.onps. their close 
 approximation or actual contact over large areas, and their wide 
 separation in other places, we are compelled to the conclusion 
 that there are no two groups, of similar comi)osition, in the en- 
 tire paheo/.oic series, which are so clearly distinct and which can 
 be unmistakably traced over so wide an area of country, both in 
 their physical and lithological character, as well as in their con- 
 tained fossils. 
 
 That there are designations among some of the formations 
 
 ♦Wem.ayliKiuli-ealsowlieUicr it may not be infoneil tliat tlio living organisms of 
 tlio lower IleUlin-berg poriod were s-pread over a sea bottom covered with llie dead 
 organisms of the preceding period and became mingled m this manner. 
 
 
 -."Si^iS^ 
 
\vin<2; the 
 siliccods 
 I'o- fossils 
 
 t'OIlfltlllo 
 
 oxisUiice 
 Jic iKiiiie. 
 ilatiire (jf 
 
 from Uic 
 jMissoui'i 
 lis lie l)e- 
 •<>■ fossils ; 
 fossils ill- 
 lie ill the 
 kvii ol)ser- 
 1(1 though 
 iiioiig the 
 ielderbei'g 
 ks ('(( sifit. 
 pcssiiry to 
 iiids both 
 distinctly 
 roup, 
 ids fossils 
 which, ill 
 len. And 
 sm of the 
 n in order 
 
 fi\ 
 
 \ 
 
 B. NATIUAL lIIsrOUY. 
 
 Which are superflnons, we are willing to admit ; hut the i-ropo 
 
 sition to drop from the system one 
 
 the most widely distrildited 
 
 formations of the country, whos.- geological position and ivlatioiis, 
 and the fossil contents of which aiv so well known, is scarce.y 
 the i)roper mode of improving -the n.nueiiclature of the Amer- 
 ican rocks." 
 
 [I'nutfd iit tlie s.vi.KM I'ui:»s. .Iiuic. 18Tt. 
 
 range and 
 heir close 
 their wide 
 conclusion 
 ill the eii- 
 which can 
 •y, both in 
 their con- 
 
 ronnations 
 
 orgnnisras of 
 vith tlie deuil 
 
i 
 
 r 
 
r.i 
 
 ^..