ES SMITHSONIAN of BASS FC ews 2 ] = FS 4°" Vauny w ane — w” = wn | ES SMITHSONIAN INSTITUTION NOILOLILSNI_ NVINOSHLINS SA1UNVH = Say = 4 < = - = — yyy = = \. 77 2 SQ. = te Gi O = \ oO RRNA "YT ff .,” o Sg E QS 34 Ge * 2 : hen q 0] Mm wo INSTITUTION NOILNLILSNI NVINOSHLINS $93 luvus i, , 7 . Oo S SK’ m Pe i ‘ — I i . Ee ay Meee = : = - “GZ - = SNI_NVINOSHLINS S3ZIYVYEIT_ LIBRARIES. SMITHSONIAN _ AS NVINOSHLINS S3luYvVudiT LIBRARIES SMITHSONIAN NVINOSHLIWS SMITHSONIAN NVINOSHLINS SJ3IYVU! JES SMITHSONIAN _INSTITUTION NOILNLILSN SMITHSONIAN Ww pear wo =— wn = = ~~. y y =e o — fod ivy Z = < 4 < sp 5 ud) 5 au) 2 ® 4 za -4 = ot, : ae SNI NVINOSHLINS S3SIYVYSIT LIBRARIES Not BS Sig = . > z ni ¥ ia N Ss 2 a = 4, 2 (sh 5 UNE = fs <> lee a XS "= c a je CAL. m Wy ot m ei y m NBosne ” eon w _ un yee ES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLIWS say wn ze wo z Gas 3 < = 7 a a = Zz = z a 2 f= Zz iS ZY SNI NVINOSHLIWS LIBRARIES SMITHSONIAN INSTITUTI > ” = no a 7) pd 7) 1a | us Jee t, DP Keawen va ie of < YY ya : S aad Cc fad d ny A Cc ye a. US Ps = rere ies a Vas 5 ~\ om 5 eal OQ. ) TR iz a z Wee se yo ee ES SMITHSONIAN INSTITUTION NOILNLILSNI” NVINOSHLINS Sa1lyvuE ree +> ee =z ~ of Sie w 2 aaa ba Ms . « wn . 72 NO oy 2 ay nS we m ne z ASH m iNoses - , m NOSH w — ets 1ES SMITHSONIAN INSTITUTION NOIJLOLILSNI NVINOSHLINS S3IUYYV wo ae wo = wn” , S < = ; < = c= | z 4 = =r = oO — & = CE 2 WN B ‘2 3 2 = AS 2 = Zz > =. XS >” a. > = ” has z ” z LSNI py tava LIBRARIES SMITHSONIAN INSTITU) - NOILNLILSNI NOILNLILSNI LIBRARIES TES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLINS S31uVe SJIYVYGIT LIBRARI INSTITUTION NOILNLILSNI INSTITUTION INSTITUTION 1SNI_NVINOSHLINS S31YVYUAIT_LIBRARIES SMITHSONIAN INSTITU NVINOSHLINS S3IYVYEIT “” < = ee 4 < WS < ys = By o AWA : O , 0 OY a ‘ \. y 2G = . - a = | a ‘ 2 | ES SMITHSONIAN _ INSTITUTION NOILNLILSNI_ NVINOSHLIWS Salve ee ts q # =. Wl 4g = c 4 NS — > i > a “tg +) — 2) pin = os rind - ; oat o z Oo z o im INSTITUTION NOILNLILSNI _NVINOSHLINS $3 luv = ts ec Va Ss =) aa 4 z a z z 3 Oo m4 oe x 72) 77) cn wn ry SC = Ye = e) ~ = Ee = os = ae ic 5 = : LSNI_NVINOSHLINS | _LIBRARIES SMITHSONIAN _INSTITU >, & ud Fe ul Fr fe) = o = = Se 6} _< = < S = yt aes oc & Pe; S oS Ss ise) 5 or = z pe 2 ps S oD -@ a) CRAITLIC PALL ARE ‘ttle at ate oe. aesme eo m6 ht oe amaee wriwltt?Y.+. (an atTre, 4 ee oP) “vie a a a on Bete Education Department Bulletin Published fortnightly by the University of the State of New York Entered as second-class matter June 24, 1908, at the Post Office at Albany, N. Y., under the act of July 16, 1894 No. 525 . ALBANY, N. Y. - AUGUST 15, 1912 New York State Museum Joun M. Crarke, Director Museum Bulletin 162 THE LOWER SILURIC SHALES : OF THE MOHAWK VALLEY _ BY RUDOLF RUEDEMANN PAGE PAGE Seer eR, ee oP er en 66 Seeeamtoar sketch... 1s... 26. eee ns 7 | Bibliography ..... ge 69 “Utica” shale of authors......... 15 | Paleontological notes............. 73 ES eo ee 34 | Explanation of plates............ 125 Schenectady formation........... ay 4) Was Gos Vs ee ke 145 Indian Ladder beds.............. 50 oe ' ALBANY UNIVERSITY OF THE STATE OF NEW YORK IQI2 epsee-DKyt2-1500 ‘ . ° ion .7 on ipest at ata ff Pa ei soi lO ¢)) ™ \ - to,» % \ 4 : \ STATE OF NEW YORK EDUCATION DEPARTMENT Regents of the University With years when terms expire 1913 Wurreiaw Rew M.A. LL.D. D.C.L. Chancellor New York tgt7 St Crain McKetway M.A. LL. D. D.C. Vice Chancellor ---->-----—-----.- - Brooklyn 1919 DANIEL BEACH Ph.D. LL. Boe = -- = = = =a 1914 Piiny T. Sexton LL.B. LL.D. - - ----- Palmyra 1915 ALBERT VANDER VEER M.D. M.A. Ph. D. LL.D. Albany - 1922 CHESTER S. Lorp M.A. LL.D. - - - ----- - New York 1918 Witt1am NorrincHaM M.A. Ph.D. LL.D. — — Syracuse 1920 EuGENE A. PuitBin LL.B. LL.D. - -.- - - - New York 1916 Lucius N. Littaver B.A. - -------- - Gloversville 1921 Francis M. CarRPENTER —- —- -------- Mount Kisco 1923 ABRAM I. Erxus LL.B. - ---------- ‘New York 1924 ADELBERT Moot -—------------- Buffalo Commissioner of Education > ANDREW S. Draper LL.B. LL.D. Assistant Commissioners Avcustus §. Downrnc M.A L.ED. L-L.D. Fie ee CHARLES F. WHEELOCK B.S. LL.D. Second Assistant Tuomas E. FINEGAN M. A. Pd.D. LL.D. Third Assistant Director of State Library James I. Wver, Jr, M.LS. ee Director of Science and State Museum "ee heal >. Joun M. CrarKe Ph.D. D.Se. LL.D. Chiefs of Divisions . Administration, GEorcz M. Witey M.A. 7 Attendance, JAMES D. SULLIVAN ee Educational Extension, Wittiam R. Eastman M.A. M.E.S.. | Examinations, HarLAN H. Horner B.A. History, JAMES A. HoLpEnN B.A. Inspections, Frank H. Woop M.A. ‘Law, Frank B. Girpert B.A. Library School, FRANK K: WALTER M.A. B. L. Ss. Public Records, THomas C. QuINN School Libraries, SHERMAN Wix.iams Pd.D: Statistics, Hrram C. Case Visual Instruction, ALFRED W. Asrams Ph.B. Vocational Schools, ARTHUR D. "DEAN B.S. New York State Education Department Science Division, May 14, 1912 Hon. Andrew S. Draper LL.D. Commissioner of Education Sir: I have the honor to communicate to you herewith a manu- script entitled The Lower Siluric Shales of the Mohawk Valley, with accompanying plates. This work has been prepared by Dr Rudolf Ruedemann,. Assistant State Paleontologist, and is the result of careful and protracted observations. I recommend it, subject to your approval, for publication as a bulletin of the State Museum. Very respectfully Joun M. CLarKE Director STATE OF NEW YORK EDUCATION DEPARTMENT COM MISSIONER’S ROOM Approved for publication this 15th day of May 1912 Commissioner of Education Compliments of JOHN M, CLARKE Director State Museum and State Geologist STATE HALL, ALBANY, N. Y. + Wowie ronan ih, hon SER CLE | yeah Yeh), kine Education Department Bulletin Published fortnightly by the University of the State of New York Entered as second-class matter June 24, 1908, at the Post Office, at Albany, N. Y. under the act of July 16, 1894 No. 525 ALBANY, N. Y. AUGUST 15, 1912 N ew York State Museum Joun M. Crarkxe, Director Museum Bulletin 162 Pee LOWER SILURIC SHALES OF THE MOHAWK VALLEY BY RUDOLPH RUEDEMANN INTRODUCTION While engaged in mapping the shales of the Saratoga and Schuylerville quadrangles of the State of New York, the writer has found that in order properly to correlate the formations of fossili- ferous shales appearing there with the standard formations of the State, it would be necessary to trace their relation to the Utica and Frankfort shales through the Mohawk valley. In beginning this task in Schenectady county, an unexpectedly large and interesting fauna was found in the “ Frankfort shale” of that county hitherto considered as practically barren. This discovery promised a safe conclusion as to the as yet unknown faunal and taxonomic relations of the Frankfort shale to the Utica shale on the one hand, and to the Lorraine beds on the other. The close faunistic and strati- graphic relations of the Frankfort shale to the Utica shale were early recognized in the work, and as the writer had previously (title 60', page 44) obtained evidence of the different faunal aspect of the “ Utica shale” of the lower Mohawk from the typical shale at Utica, it was found desirable to include the Utica shale in the investigations. 1See Bibliography, p. 60. 6 NEW YORK STATE MUSEUM It was further found that beds formerly considered by the author (op. cit., page 29) as representing one formation (the Magog), had to be divided into two units, the Canajoharie shale and the Snake Hill beds. These beds are not only in juxtaposition about the mouth of the Mohawk, but even intermingled in that much-folded territory, and we originally considered them as both belonging to the Mohawk series and therefore have described also the Snake Hill beds in this paper. Later work has, however, shown that the Snake Hill beds were deposited in the Levis basin upon the Normanskill shale and have been brought to the mouth of the Mo- hawk and in contact with the Canajoharie beds by the overthrusting and compression of the shales of the Levis basin. We have never- theless added the description of the Snake Hill fauna in the present paper, first, on account of its present occurrence in the lowest Mohawk valley, then, because of the intermixture of Snake Hill beds with Canajoharie shale, and, finally, because of the faunal similarities suggesting their equivalence. The Snake Hill forma- tion finds, however, its principal development in the area of the Schuylerville sheet, and will therefore be more fully described in the report on that region, soon to be published. Evidence was soon obtained that the lower part of the Utica shale of the lower Mohawk valley is older than the typical Utica shale and probably of Trenton age, and it would have been desirable to also trace the Trenton limestone from its type section at Trenton Falls to its much smaller section in the lower Mohawk valley. Time was lacking for this undertaking but fortunately Doctor Ulrich has furnished us important data as to the Trenton limestone, and we are glad to acknowledge here our obligation to him not only for this information, but also for advice in the identification of fossils, and many valuable suggestions as to the broader bearings of the problem. We are also under obligation to Mr David White for the valuable - notes on the interesting seaweeds collected in the Schenectady shale (see page 73), to Prof. Bashford Dean, Dr LB Gratacap, Dr H. A. Pilsbry for advising us in regard to the problematic fossils from the Schenectady shale, here described (see page 74), to Prof. A. F. Foerste for information regarding certain brachiopods and to Dr E. O. Hovey for the loan of type specimens from the American Museum of Natural History. LOWER SILURIC SHALES OF THE MOHAWK VALLEY v4 HISTORICAL SKETCH A perusal of the literature shows that the Utica and Frankfort shales have received scanty attention from geologists, quite obvi- ously because they promise little, if any, results, the Utica shale fauna consisting largely of small species difficult of study. The Frankfort shale was declared by Vanuxem to be remarkably deficient in all organic remains excepting graptolites. A fairly full account of the two was given by Vanuxem in the Geology of the Third District. This astute observer distinguished the Utica slate and the Frankfort slate; the latter as a subdivision of the Hudson River group or Lorraine (Emmons), the other member being the Pulaski shale. He states that in his district (which included the Mohawk valley) the Utica slate is everywhere underlain by the Trenton limestone and overlain by the Frankfort shale and sandstone; that both the Utica and Frankfort beds enter his district from the first district on the lower Mohawk and are coextensive there, while the Pulaski shale first appears much farther west in Oneida county. The Utica slate is characterized as deep bluish black rock, generally fissile, exhibiting a brownish or dark chocolate color by weathering and associated with thin layers or flags of dark colored impure limestone, especially in the lower part of the mass. As character- istic fossils, that do not come up from the Trenton, are cited: merarearus, becki, Graptolites dentatus Seen ipl. foliaceus or .Glossogr. quadri- mucronatus), a mutation of Trocholites ammo- eegs and Graptolites scalaris (Diplograptus and Climacograptus viewed from in front). The Frankfort slate is stated by Vanuxem to change by imper- ceptible gradation from the Utica slate, “‘ yet a separation would - seem obvious from the fact that the dark blue or black color of the latter disappears in the usually light color of the former. While the Utica slate alternates at its lower part with thin beds of dark colored impure limestone, the Frankfort slate, on the contrary, alternates. with a peculiar sandstone to which Professor Eaton gave the name of rubblestone; and while the Utica slate is calcareous, the Frankfort slate is wholly destitute of calcareous particles.” He continues: “‘ Both slate and rubblestone ” (greywacke of Eaton, an impure argillaceous sandstone), “lose their bluish color when long exposed, and assume a dull dark gray, green ‘or olive color, which is very characteristic of this rock, and by which it is readily 8 NEW YORK STATE MUSEUM distinguished from the Utica slate, which as before mentioned, changes to a brown.” Vanuxem comments on the thinning of the Frankfort beds westward and it is obvious from his remarks (page 61) that he also considered the greater part of the shales in the Hud- son valley as of Frankfort age, largely on account of the intercalation of similar rubblestone or greywacke. He describes the Frankfort shale as remarkably deficient in organic remains, stating: ‘“ From the eastern end of the Helderberg to Oneida county, I have seen but one fossil shell in the whole mass.” Only graptolites are said to be numerous in a few places; this statement, however, refers principally to the shale in the Hudson valley, which we no longer refer to the Frankfort beds. He also found a small specimen of Triarthrus beckr -and two of TI Frimeeieteeee concentricus (© Cryptolithas:)). In the middle Mohawk valley the Frankfort slate is capped by the Oneida conglomerate, but in the upper valley and to the west. of the Adirondack region it is overlain by the Pulaski shale, or rather it is separated from the typical Pulaski shale by an “ inter- mediate area”’ (Vanuxem, page 64) with a separate fauna which Vanuxem considered a lower subdivision of the Pulaski shales. Hall, in volume 1, Palaeontology of New York, brought out the fundamental paleontologic data for the formation in question. He distinguished the faunas of the Utica slate and of the Hudson River group, the latter comprising all the horizons of the shales in the Hudson valley, including the Frankfort and Pulaski (Lorraine) beds. In volume 3, Palaeontology of New York, Hall extended the term Hudson River group to “all the beds from the Trenton limestone to the Shawangunk conglomerate,” a conception which was taken up by the textbooks and came into general use. 7 In an attempt to correlate the Normanskill shale with the Utica formation, Whitfield (title 7) cited several Normanskill grapto- lites (Didymograptus serratulus, Daepaaeee graptus ramosus, Climacograptus bi¢ ow mee from the Utica shale of the neighborhood of Fort Plain in the Mohawk valley as proof. of his contention. The writer has shown (1901, 1908) that this view is based on the wrong identification of these graptolites. It had, however, an important influence in inducing later authors to refer a large part of the shales of the Hudson valley to the Utica shale. Pe rn ae LOWER SILURIC SHALES OF THE MOHAWK VALLEY 9 Walcott (title 9) in his “Utica Slate and Related Formations,” distinguished the Utica epoch from the Trenton and Hudson River epochs and added a considerable number of new types (two species of the sponge genus Cyathophycus, species of graptolites of the genus Dendrograptus, Leptograptus annectans and a few other forms) to the list of hitherto known Utica species. In his “ Catalogue of Fossils Occurring in the Utica Slate” (page 34), he brought the Normanskill shale with its graptolites into the Utica shale as an upper division. The geographic distribution of the Utica shale within and outside of New York was fully discussed by him. The presence of passage beds between the Trenton lime- stone and Utica slate in the region of the type section is also commented upon (page 10). The thickness of the Utica shale, before greatly underestimated, is given as over 600 feet at the type section. 7 Beecher published in 1883 (title 13) a list of fossils from the black shales near the old Dudley Observatory, at Albany, referring the beds to the Utica epoch and Ford, a year later, recorded the discovery of a few fossils (Graptolithus pristis, Gr. Meer onatus, Triarthrus becki and Lingula curta) in the slaty and arenaceous rocks in the vicinity of Schenectady, which on the strength of this evidence he also consid- ers as of Utica age, while the preceding authors (Vanuxem) had referred it to the Frankfort slate, respectively Hudson River shale (Mather, Emmons). In 1890, Walcott in a paper on “ The Value of the Term Hudson River Group,’ asserted the continuation of both the Utica slate and Frankfort shale into the Hudson valley, thereupon basing his argument for the extension of the term “ Hudson River group” to all beds between the Trenton limestone and Upper Siluric. As before, he included the Normanskill shale in the upper Utica epoch or lower Frankfort. The fauna discovered by Beecher at the Dudley Observatory was correlated with the upper Utica and that from the glazed slates at Cohoes (whence Hall in Palaeontology of New York, volume I, reports Ambonychia radiata, etc.) to the Frankfort shale. The important fact is pointed out that a well drilled at Altamont (Knowersville), 17 miles west of Albany, gave a thickness of 3475 feet for the strata between the Lower Helderberg limestone and the Trenton limestone. On account of its proximity this section allows a good estimate of the great thickness of the Utica and Frankfort shales in the lower IO NEW YORK STATE MUSEUM Mohawk region, which is only about 10 miles to the north over a continuous outcrop of Frankfort beds.* Darton did not make any special study of the Utica and Frank- fort beds for his “Geology of the Mohawk Valley” (1893). Of great importance for the present work were the investigations of Prosser and Cumings (titles 33, 44). They described a number of sections through the Utica slate and the Frankfort beds (their Hudson River group) and demonstrated the great thickness of these groups in the Amsterdam quadrangle (Utica 950-1260, Frankfort 1200 +)% Among other things, they made known in the Minaville section a complete transition from the Utica to the Frankfort beds. From the base of the Minaville section a fairly complete section can be obtained along Chuctenunda creek through the Utica down to the Trenton limestone and thus it has been pos- sible for us to study a continuous section from the Trenton to the Frankfort in the lower Mohawk valley. A list of eighteen species is given for the Utica slate at Canajoharie, and a small faunule recorded from the Hudson River shale near the Schenectady pump station, namely, Triarthrus becki, Trin wel ei eueeee centricus, Plectambonites, sericeus.. nee (Dalmanella) testudinaria, Or Dieu sp., Monticulipora (Prasopora ) #ijgemeoeee don, crinoid segments and graptolites. A few notes on the Frankfort shale sections along Moyer creek near Frankfort (the type section) and Ferguson creek near Utica were published by Theodore G. White in 1899 and the presence of Trtarthrus becki, a small Orthis, a small (cpg and graptolites recorded in these sections. Purely paleontologic papers on fossils from the Utica slate of the Mohawk valley were published in the decade of 1890-1900 by Beecher on Triarthrus becki and by Ruedemann on the development of graptolites, and a sessile Conularia. Ruedemann (title 36) also demonstrated that in the Utica shales of the Mohawk valley distinct evidence is found of marine currents following a northeast-southwesterly course. 1 The terms Trenton limestone, Utica and Frankfort shales are used in this introduction in their old meaning, not in the restricted conception given to them in this paper. 2Cumings (1900, page 462) measured an actual thickness of the Utica slate of 1160 feet in the Adebahr hill section. mai 2 Se a Se NN peeaiicttieeme iat cementite open a tea a a ee LOWER SILURIC SHALES OF THE MOHAWK VALLEY re ' In 1901, the author (title 47) in his bulletin on the Hudson River beds near Albany, correlated the Normanskill shale with the lower Trenton and argued on this account for the suppression of the term Hudson River group. He also pointed there (page 560) to the decrease of the thickness of the Trenton limestone eastward in the Mohawk valley and the rapid increase of the “ Utica”’ shale in the same direction. In the following years the author also showed the presence of graptolite zones ranging from the top of the Cambric - through the Beekmantown and Trenton to the Utica in the Hudson River shales. A broad belt of shales on the west side of the Hud- son overlying the middle Trenton shales and Normanskill shales was still referred to the Utica shale; and the shales at Cohoes and to the west of the Utica belt were in accordance with Hall and Vanuxem correlated with the Frankfort division of the Lorraine group, mainly on the ground of a series of small lamellibranchs obtained -about Cohoes and of the supposed upper Utica aspect of the Dudley .. Observatory faunule. In 1902 Paleozoic Seas and Barriers in Eastern North Amer- ica by E. O. Ulrich and Charles Schuchert was published. This. very important paper, which apparently has not been sufficiently understood or appreciated by many, has helped greatly in the elaboration of the complex shale problems by pointing to the exist- ence of separate troughs or channels in the shale region (the Chazy and Levis troughs) of New York and to the draining of these channels independently of each other. Clarke in the Classification of the New York Series of Geologic Formations (title 52) discarded the term Hudson River and dis- tinguished the Utica shale and Lorraine beds as stages of the Cin- cinnatian ; the Frankfort shale, Pulaski and Salmon River being con- sidered as “early terms applied to the local development of these beds in central New York.” In an excellent description of the Geology of Little Falls, Cush- ing (1905) pointed out the presence of 100 feet of passage beds between the Trenton and Utica. He says: “ Lithologically these beds are no more Trenton than they are Utica but are distinctly intermediate in character, and no more to be classed with the one formation than with the other.” He mapped them as a distinct unit, and in a later communication to Professor Miller (title 65, page 21) he proposed the term Dolgeville shale for these passage beds, considering them a formation “as a shaly eastern repre- sentative of the upper Trenton limestone of the type section.” I2 NEW YORK STATE MUSEUM These beds were found by Miller (title 65) to be absent on the Remsen quadrangle which adjoins the Little Falls quadrangle to the west. The graptolites of the Utica shales and supposed Frankfort beds of the Hudson valley have been fully described by the author in volume 2 of Graptolites of New York (1908). The Utica shale is there characterized as the zone of -GloSso¢gr. @iaau mucronatus and Climacograptus ty paca The presence of subzones and the difference of the faunas in differ- ent districts especially that between the fauna of Holland Patent and the lower Mohawk is pointed out, and the fact brought out (page 36) that the Utica faunules of the Appalachian trough differ from those of the Mohawk valley by the frequent occurrence of Corynoides ‘calicularis* which latter only semper the lower Mohawk valley. The transgression of the Utica shale ~ from the northeast is inferred from the faunal evidence and as corollary of this transgression the conclusion drawn (page 49) that the boundary between the Trenton limestone and Utica shale is not a plane of synchrony, and that the areal restriction of the Corynoides to the lower Mohawk valley may be due to the greater age of the eastern Utica beds and its absence farther west, or to the replacing of the shale by the lower Trenton limestone. The Utica of the Hudson valley is thought to be separated by the Magog shales from the lower Trenton Normanskill shale. The faunule of the Frankfort shale is described from the sup- posed Frankfort beds at Waterford and Mechanicville. In a paper by Grabau on the Physical and Faunal Evolution of North America during Ordovicic, Siluric and early Devonic Time (1909) the relations of the Trenton and Utica are stated as follows: The Trenton limestone of America is not a stratigraphic unit, but, as has been repeatedly demonstrated by Ruedemann and noted by many observers, it is the limestone phase of a series which else- where is in part or mostly represented by Utica shale. In the Mohawk valley the dividing line between Utica and Trenton is a line constantly rising to the west, the transition being in some cases abrupt, though probably in most cases it is gradual. Ruedemann has pointed out the progressive increase in thickness westward of the limestone, and corresponding decrease in the shale; the former increasing from 40 feet at Saratoga to 430 feet at Utica, and to 954 feet at Rochester, while the latter decreases from 1260 feet to 710 feet to probably zero over the same localities. . . . The 1 Erroneously there referred to C. curtus. ew LOWER SILURIC SHALES OF THE MOHAWK VALLEY 13 various sections clearly show that along the western border of the Appalachians, dark graptolite shales continued to form in Upper Ordovicic time, while westward from this the Trenton limestone represents the calcareous phase of the Utica-Trenton series (see map, figure 8). | _ In a diagram that accompanies Professor Grabau’s paper (op. cit. figure 9), the Utica is represented as wholly replaced by Tren- ton limestone in the latitude of Rochester and farther west. In the description of the Remsen quadrangle Miller (title 65) has shown the absence of the Dolgeville beds in the area adjoining the Little Falls quadrangle to the west. He found the Utica to be only 300 feet thick indicating a notable thinning to the northwest from the type section. Two hundred feet of Lorraine beds were observed which were found to be destitute of fossils and are not separated by an exact boundary line from the Utica. There is little doubt that these beds are the Frankfort shale. This decrease is in a later bulletin (title 66) by the same author shown to be steady toward the north. It would also become probable from the same paper that the Frankfort shale with a thickness of about 200 feet continues to the northwest and intervenes there between the Utica shale and Lorraine sandstones and shales with the characteristic Lorraine fauna (page 33). To the south of New York, in New Jersey, Pennsylvania and West Virginia, the shales which formerly were termed “ Utica and Iludson River slates” are now known as Martinsburg shale. The Martinsburg shale of the Mercersburg-Chambersburg quadrangle in Pennsylvania has been described by Stose, and fossil lists given by Ulrich (title 61, page 10). The lowest shale fauna is con- sidered as indicating an age corresponding to that of the lower to middle Trenton of New York, and the highest as comprising species characterizing the Eden shale. Bassler, in his work on the Cement Resources of Virginia (title 62), the Federal Survey’s part of which was done under the official direction of Doctor Ulrich, divides the Martinsburg shale in three div.sions, namely, upper Trenton shale, Utica shale and Eden shale, representing the shaly Ordovicic deposits of: the Appalachian trough. The Martinsburg is continuous from Vir- ginia through Pennsylvania and New Jersey with the shale belt of New York, and this division of the shales has a direct bearing on that of the shale in the New York part of the Appalachian trough, represented by the shales in the Hudson valley. 14 NEW YORK STATE MUSEUM Schuchert (1910), in his monumental Paleogeography of North America, refers the Utica of New York as the zone of the Mastigograptus fauna to the top of his Ordovicic period. As characterizing the shale facies of the Trenton in the Atlantic province are cited the Climacograptus “cage Corynoides curtus and Magog graptolite zones, while the horizon of the Normanskill shale is correlated with the Black River of New York and Kimmswick of Illinois and Missouri. The Frank- fort is correlated with the Edenian and placed in the Cincinnatic period, the Ordovicic period being considered as closed by the Utica emergence. Paleogeographic maps of North America in the late Trenton and Utica stages by Ulrich and Schuchert are given, to which we will have occasion to refer. A new light has been shed on many problems, here involved, in the Revision of the Paleozoic System by E. O. Ulrich (title 68), the first volume of which appeared after this paper was written, but as much of the information therein published was freely given to the author in the joir: field excursions in the Mohawk and Hud- son valleys, its principles have been applied to a considerable extent to the questions that arose in this investigation and the conclusive answers obtained are clear evidence of the truth of some of these principles. We have here especially in mind Ulrich’s theories of a multiplicity of shallow continental seas and of frequent and periodic migrations of faunas from _ their permanent oceanic habitats into these inland seas. In the investigation of the Utica and Frankfort shales in the Mohawk valley, the entire mass of shales between the Trenton limestone at the base and the Upper Siluric rocks on the top were studied in the region from Cohoes at the mouth of the Mohawk to the neighborhood of the city of Utica and of Holland Patent. In the lower Mohawk region for the most part a broad plain of deep drift intervenes between the Mohawk river bluffs and the foot of the Helderberg escarpment; only two sets of sections were therefore accessible in greater numbers, one at the base of the shales in the ravines near the mouths of the southern tributaries of the Mohawk and another in the upper Frankfort beds in the ravines cut into the lower slopes of the Helderberg escarpment. The Chucte- nunda creek furnished here the most satisfactorily continuous sec- tion, leading from the Trenton limestone to the Schenectady beds. The Canajoharie creek and Flat creek at Sprakers afford two excel- © lent sections through the lower “ Utica beds ” (here distinguished as | | | ‘papeys si evaie apeys oy, ‘sAoyjea uospnzy Joddq pur YMEYOW 3} Ul WEaq ajeyS oy Jo dew AyyRooT 1 amBy UNAIg] May, és One Saye ae \ umojsag (Yelm) ee WLG) [PLLYLY)) Sian AN (e) Gy Q s shannids SPR] UOPUIL ; LOWER SILURIC SHALES OF THE MOHAWK VALLEY 15 Canajoharie beds), the East Canada creek one from the Trenton through the transition beds into the lower Utica, while Moyers creek at Frankfort and the “ Gulf” at Ilion give excellent sections through the Frankfort shale but fail to show its base. No continu- ous Utica section has been found in the neighborhood of Utica; the name according to Vanuxem is derived from the exposures in the Starch Factory creek (page 58, “a creek to the east of the city”), now largely within the city. The most important of these sections are here discussed in detail. Pe tCA” SHALE. OF AUTHORS + The belt of black “ Utica” shale that follows the south side of the Mohawk valley is cut off by the Hoffman Ferry fault, as is well shown in the geologic map of the Amsterdam quadrangle by Prosser, Cumings and Fisher, to be replaced by an area of “ Hudson River ” or “ Frankfort’ beds that occupies nearly all Schenectady county and toward the east merges into the zone of folding. Just west of this fault, between Hoffman Ferry and Amsterdam, the south bank of the river is formed by cliffs of Little Falls dolomite and Trenton, above which, according to Prosser and Cumings, the contact of the Trenton and “ Utica” is seen in several places, which have been visited by the writer. In the Swartztown creek section (title 45, page 472; title 44, page 457) two feet of black partly noncalcareous, but mostly cal- careous shale? is exposed overlying very fossiliferous Trenton. The contact in this section which is the first west of the Hoffman Ferry fault is disconformable and the surface of the Trenton irregular. The fossils are: Corynoides calicularis Nicholson Dicranograptus nicholsoni var. parvulus nov. Diplogr. (Mesogr.) mohawkensis nov. A mile farther west is a section opposite Cranesville (title 33, page 653) in which about 21 feet of basal Trenton, over- lying the Amsterdam limestone , ormerly Black River) with 17t will be shown in this paper that both the Utica shale and Frankfort shale of the lower Mohawk valley are of another, earlier, age than hitherto supposed. They will therefore, in distinction from the true Utica and Frankfort shales, be cited in quotation marks, until differently named. 2The “Utica” shale 1s uescribed as calcareous in distinction from the Frankfort shale. The two have therefore been distinguished by Professor Prosser in the field by the use of the acid bottle. 16 NEW YORK STATE MUSEUM a little of the calcareous basal Utica shale, is shown. This again contained Corynoides calicwl an aeayeeees Diplogr. (Mesogr:) moma w k eniswee ie - An excellent section of the Trenton and basal “ Utica” shale is exposed in Morphy creek, (title 33, page 654; title 44, page 460) halfway between Cranesville and Amsterdam and about one and one-half miles west of the preceding section. Here 5 feet of Amsterdam limestone are overlain by 37° feet) or Trenton limestone. The uppermost 27 feet are thin, irregu- lar, dark blue, limestone layers with very black shale intercalations. These beds abound in Prasoporas, Trinucleus concen- tricus, Calymmene senaria, but comes graptolites. The black calcareous Utica shale follows abruptly with profusely graptolitiferous beds, the species being: Dicranograptus nicholsoni var. parvulus nov. Diplogr. (Mesograptus) mohawkensis nov. Diplogr. cf. putillus (Hall) Rafinesquina alternata (Emmons) (small) Leptobolus insignis Hall Orthoceras sp. It follows from this series of outcrops that the Lower Trenton or Prasopora zone at the eastern terminus of the continuous “ Utica” belt of the Mohawk valley is separated by a disconformity indicating a small interval of nondeposition, from black calcareous shales characterized by Corynoides ‘calicgeieaeee and a characteristic Diplograptus of the Mesograptus group. All three of these ravines reach the drift directly above the basal “Utica”? beds and no satisfactory section of the upper “ Utica ” could be obtained. The latter is found along the south branch of the Chuctenunda creek, which empties opposite Amsterdam, and reaches back into the “ Frankfort” shale hills, southwest of the village of Minaville where the transition from the “ Utica” shale into the “ Frankfort” shale is finely exposed in the ravines. The contact between the Trenton and “ Utica” is not shown in the section; the first outcrop is found at the falls of the creek, probably not more than 20 feet above the top of the Trenton. Here were found (Museum locality number 3758) : 1 Diplograptus amplexicaulis (ce) Diplograptus (Mesograptus) mohawkensis Cc) Lasiograptus eucharis (r) Leptobolus insignis. peer 1c¢e—very common, c=—common, r—rare, rr—very rare. ee? ein ne — LOWER SILURIC SHALES OF THE MOHAWK VALLEY 17 The next outcrop which furnishes fossils is in a small creek, coming in from the west, at the second bridge above 1, about 220 feet higher in the section. Here were found (Mus. loc. 3759): 2 Corynoides calicularis (cc) Diplograptus foliaceus acutus (cc) Triarthrus becki (c) A third fossiliferous outcrop was found along the main Chucte- nunda creek one and three-fourths miles west by south, 70 feet above the preceding. This has furnished (Mus. loc. 3760) : 3 Diplograptus (Mesogr.) mohawkensis (cc) Lasiograptus eucharis (with colonies) (cc) Leptobolus insignis (c) Triarthrus becki (r) Orthoceras sp. (r) There follow continuous outcrops for half a mile, all of, which contain (Mus. loc. 3761): 4 Diplograptus (Mesogr.) mohawkensis (cc) Lasiogr. eucharis (cc) At the end of this series of outcrops, about 30 feet above 3, (Mus. loc. 3762) Lasiograptus eucharis has become by far the prevailing fossil. There occur: 5 Diplograptus (Mesogr.) mohawkensis (c) Lasiograptus eucharis (colonies) (cc) Leptograptus insignis (r) A quarter of a mile farther up, beyond the fourth bridge (Mus. - loc. 3763) the following fossils were obtained: 6 Diplograptus (Mesogr.) mohawkensis (c) Lasiograptus eucharis (cc) Leptobolus insignis (r) Triarthrus becki (c) > Three-quarters of a mile farther up, (Mus. loc. 3764), just, below the village of Minaville and 300 feet above the first outcrop only 7 lLasiograptus eucharis, and Leptobolus insignis were collected. The next outcrop which is half a mile above Mina- ville is the base of the Minaville section, described by Cumings 18 NEW YORK STATE MUSEUM (title 44, page 463). Here in black, slabby calcareous shale were collected (Mus. loc. 3765): 8 Climacograptus cf. putillus Lasiograptus eucharis Leptobolus insignis In a gully about one and two-fifths miles south by southwest of Minaville a continuous section 255 feet thick is exposed, which exhibits a complete transition from the typical lithologic character of the “ Utica” to that of the “ Frankfort.” This section has been measured by Cumings and the following lithologic divisions dis- tinguished : K4 Mostly covered. Thin sandstone and arenaceous shales with a massive 2 foot layer at the base in the head of the glen. 120 —— ae K3 Black shales becoming olive to blackish at the top. These shales show a transition from the black calcareous shales of the “ Utica”’ to the arenaceous, thin, crumbling shales of the “ Hudson River” stage. 165’ == 42a K2 Top consisting of sige layers containing grapes in abundance. Black, even shale. QO’ == 25s Kr Mostly covered, but showing brown in weathering, slabby shale in the west bank of Chuctenunda creek, just above Mina- ville. 165’ ==165, While Ki of this section has furnished the faunule cited under 8, the following division K2 was found to contain still, at least in its lower part (Mus. loc. 3770), specimens of 9 Diplogr. (Mesogr.) mohawkensis Near the top (Mus. loc. 3769) a zone appears that is character- ized by 10. Climacograptus spiniferus (ec) Lasiograptus eucharis ; K3 proved fossiliferous in one part (Mus. loc. 3768) where Iz Climacograptus spiniferus occurs in great profusion. The shales in this division, although still carbonaeeea and very black like the “Utica ” shale, 8 not any more react with HCl and are not calcareous. eee ier ie nee ate Ae LOWER SILURIC SHALES OF THE MOHAWK VALLEY 19 K4, which consists prevailingly of thin sandstone and arenaceous shales of “ Frankfort” aspect, still contains bands of black argilla- ceous shale, which usually yield graptolites on examination. At the base (120 feet from the top sandstone layer of the section) a band (Mus. loc. 3767) has furnished: 12 Climacograptus typicalis | (c) Lasiograptus eucharis (cc) The Lasiograptus eucharis occurs in an unusually large and broad mutation. _ Another graptolite horizon was found but 22 feet from the top (Mus. loc. 3766). This contains: 13 Diplograptus (Amplexograptus) macer nov. (c) The graptolite that characterizes this fayina is an extremely nar- row and long form, hitherto not observed at other horizons and _ therefore here distinguished by a new specific term (see Paleonto- logic notes, p. 82). A survey of these localities as little suggests any sharp faunal boundaries as do the lithologic characters of the rocks. The rock is a black brownish weathering shale that strongly reacts with HCl. This character does not change until K3 (with horizon 11) is _reached, when the black shale becomes wholly argillaceous. Never- theless there is distinct though gradual change in the faunal aspect of the Utica shale as one passes upward. The basal beds at Mor- phy’s and Swartztown creeks were found to be characterized by meremoides.calicularis and Diplograptus mohawkensis, two fossils which are wholly foreign to the Utica beds of the Utica section, or to the typical Utica beds. Meerynoides calicularis is in the Chuctenunda section still abundantly found 220 feet above the base. Diplo- graptus mohawkensis remains the most common fos- sil, much longer, through 3 and 4, but in 5 it is replaced by Lasiograptus eucharis which remains the dominant graptolite to near the beginning of the transition beds, where it is somewhat abruptly displaced by Climacograptus spiniferus, (in 10) which hitherto had not been observed in the section. Then also Climacograptus typicalis appears and at the top a new species of Diplograptus. We may add that Lasiograptus eucharis, Climaco- meentus spiniferuws and Climacograptus typicalis continue into and through the “ Frankfort” shale in the lower Mohawk valley. 20 NEW YORK STATE MUSEUM | We can then distinguish three larger faunal zones, namely: 1 That of Diplograptus mohawkensis _ Corynoides calicularis 2 That of Lasiograptus eucharis 3 That of Climacograptus spiniferus Climacograptus typicalis _ Diplograptus macer All three of these zones are absent in the typical Utica section. Another series of sections through the “ Utica” shale, or at@ least its lower part, is. afforded by the gulfs of Flat creek at Sprakers and of Canajoharie creek at Canajoharie. These places are about 20 miles west of the Chuctenunda sections and halfway between the latter and the typical Utica section of the Utica region. The Canajoharie creek and Sprakers sections have been briefly described by Prosser and Cumings (title 33, page 638). They record at the former 53-+ feet of Tribes Hill (Fucoidal) limestone, underlying 17 feet of thin bedded dark blue, very fossiliferous Trenton limestone with shaly partings. A distinct unconformity separates the two. About 300 feet of very black, bituminous slate referred to the lower “ Utica” formation were found in the glen. The following fossils are cited from the Trenton: 1 Rafinesquina alternata (Con.), Hall and Clarke (c) 2 Calymmene callicephala Green (?) (r) 3. Orthis (Dalmanella) testudinaria Dalm. | (a) 4 Asaphus platycephalus Stokes (cy 5 Monticulipora (Prasopora) lycoperdon Say. | (r) 6 Modiolopsis mytiloides Hall (?) (rr) 7 . Tellinomya levata Hall (rr) 8 Zygospira recurvirostris (Hall), Winch. and Schuch. (rr) — g Plectambonites sericeus (Sowb.), H. and C. (c) 10. ©Trinucleus concentricus Eaton (r) a 11 Atrypa (Protozyga) exigua Hall (rr) 12 Ceraurus pleurexanthemus Green (?) | (rr) @ 13. Murchisonia bellicincta Hall | (rr) # 14 Murchisonia gracilis Hall (?) (rr) 15 Camarella cf. volborthi Bull. : (Esa) 16 Stictopora sp. (r) and the following from the “ Utica” which is stated to contain a larger number of fossils than has been found in the more eastern — exposures : , 1 Lingula quadrata (Eich.), Hall (?) ~ (c) 2 Plectambonites sericeus (Sowb.), H. and C. oc ite 3 Orthis (Dalmanella) testudinaria Dalm. (c) LOWER SILURIC SHALES OF THE MOHAWK VALLEY 21 4 Triarthrus becki Green (c) 5 Graptolites (a) 6 Asaphus platycephalus Stokes (r) 7 ‘Tellinomya nuculiformis Hall (r) 8 Pterinea trentonensis (Conrad) (rr) 9 (?) Edmondia subtruncata (Hall) (rr) 10 Endoceras proteiforme Hail (c) Iz Raphistoma lenticulare (Emmons) (r) 12 Trocholites ammonius Conrad (r) 13 Rafinesquina alternata (Con.), H. and C. (r) 14 Orthis (Dinorthis) pectinella Emm., var. semiovalis, Fall (rr) 15 Crinoid segment (rr) 16 Leptobolus insignis Hall (r) 17 Lingula curta Con. (a) 18 Monticulipora (Prasopora) lycoperdon Say. (tr) 19 Bellerophon sp. (rr) With the exception of a bed of compact barren limestone at the base, which has an irregular surface and is separated by an uncon- formity from the overlying beds, the Trenton is compused of thin beds of limestone alternating with layers of shale of equal thick- ness, the whole having a distinctly transitional character like the beds designated as Dolgevilie beds by Cushing. A limestone near the base is a shell-breccia and contains the brachiopods and trilo- bites cited by Prosser. This is followed by a thin bryozoan reef, from which Doctor Ulrich has identified : Stictoporella cf. angularis Ulrich S. exigua Ulrich Phaenopora incipiens Ulrich Pachydictya acuta (Hall) P. pumila Ulrich Eridotrypa mutabilis var. minor Ulrich A small reef of broken shells swept up by a current, passes through the shaly Trenton limestone. This is especially rich in fossils and has furnished (fide Doctor Ulrich): Corynotrypa inflata (Hall) Atactoporella ? crassa Ulrich Stomatotrypa ? sp. Eridotrypa mutabilis var. minor Ulrich Phylloporina reticulata (Hall) Nematopora ovalis Ulrich Arthroclema pulchellum ? Billings Rhinidictya canadensis Ulrich Pachydictya acuta (Hall) 22 NEW YORK STATE MUSEUM iP a Ulrich Stictoporella cf. angularis Ulrich S. exigua Ulrich Phaenopora incipiens Ulrich . Dalmanella futilis (Sardeson) var. Rhynchotrema increbescens (Hall) Eurychilina subradiata Ulrich var. Calymmene senaria Conrad Pterygometopus callicephalus (Hail) Trinucleus concentricus (Eaton) The shaly intercalations have afforded us: Rafinesquina alternata (Emmons) | (c} Leptobolus insignis Hall (c) Lingula curta (Conrad) (cy Dalmanites (Pterygometopus) callicephalus Hall (r) Diplograptus amplexicaulis Hall (cé} Diplograptus (Mesogr.) mohawkensis (c) Corynoides calicularis Nicholson (r) Ctenodonta cf. nuculiformis Hall (r) Ulrichia ? bivertex Ulrich (c) Primitiella unicornis Ulrich ; | (r) Small ostracods of Primitia type It will be noted that the shaly intercalations of the Trenton limestone contain two of the most characteristic graptolites cited above from the basal “ Utica” shale in the neighborhood of Amster- dam. Likewise it will be seen that also in the Canajoharie section these graptolites and all the other fossils observed in these shaly . intercalations go up into the black “ Utica” shales. The fauna of both the limestone and the shaly intercalations is © of earliest or basal Trenton age. This belt of basal Trenton limestone with the underlying Amster- dam limestone can be traced by outcrops, rather widely separated through the faulting of the region, around the southeast side of the Adirondacks to Saratoga and Glens Falls. Since these beds are lower than any exposed at Trenton Falls, their reference to the Trenton is likely to lead to confusion and they should be recognized by a distinct name. For a time we have termed them the Jackson- burg limestone, but since the latter unit, recognized in New Jersey (title 59), also comprises beds of Amsterdam and Lowville age, it is not properly applicable to the limestone in question. As the latter is best exposed at Glens Falls with the underlying Amsterdam (Black Marble) limestone and overlying Canajoharie shale, we pro-j pose for it the term Glens Falls limestone. } 3 4 } j . ” LOWER SILURIC SHALES OF THE MOHAWK VALLEY 23 The first 65 feet of the beds at Canajoharie (from the Glens Falls limestone to the lower falls) consist of calcareous shale with frequent small limestone seams near the base. The shale is deep black, calcareous, hard and splintery, brownish weathering. contains: Diplograptus amplexicaulis Hall _ Leptobolus insignis Hall Schizocrania filosa Hall Lingula curta Conrad Calymmene senaria Conrad var. Ctenodonta nuculiformis ? Hall Primitiella unicornis Ulrich It An extremely rich zone was observed in the cliff directly above the falls (65-120 feet from base). This has furnished: Diplograptus amplexicaulis (Hall) Corynoides calicularis Nicholson Diplograptus (Mesograptus) putillus Hall Lasiograptus eucharis (Hall) Sponge spicules Spatiopora sp. Leptobolus insignis Hall Lingula curta Conrad Dalmanella testudinaria (Dalman) Rafinesquina alternata (Emmons) small Plectambonites sericeus (Sowb.) H. & C. Hyolithes pinniformis nov. Prolobella ? trentonensis (Hall) Pterinea insuetat (Emmons) Ctenodonta cf. nuculiformis (Hall) Clidophorus sp. Ctenodonta sp. nov. large Whiteavesia sp. Clathrospira subconica (Hall) Liospira cf. rotuloides (Hall) Orthoceras sp. Calymmene senaria (Conrad) Lepidocoleus jamesi (Hall & Whitfield) Turrilepas filosus Ruedemann © Ulrichia ? bivertex Ulrich Primitiella unicornis Ulrich Minute Primitias 1This last species, described by Hall in Paleontology New York, 1:291, is known only from this locality. Hall states of it: ‘ This species occurs in the lower black shale, or Utica slate, at Canajoharie, and is known in the higher part of the group.” 24. NEW YORK STATE MUSEUM A third series of outcrops begins with a cliff on the north side of the creek, about 115 feet above the base and reaches to 150 feet. The shales of this are lithologically identical with the ne . rock. These beds contain: Cyathodictya ? tubularis nov. (cc) Glossograptus quadrimucronatus mut. cornutus Rued. (c) Diplograptus (Mesograptus) putillus Hall ee) Lasiograptus eucharis (Hail) (r) Spatiopora sp. (r) Leptobolus insignis Hall we) Lingula curta Hall (c) Rafinesquina alternata (Emmons) (r) Orthoceras sp. . (r) Ulrichia ? bivertex Ulrich (c) Primitiella unicornis Ulrich (c) The most novel element of this association is Glosso- graptus quadrimucronatus mut. Co@nneee This characteristic form has before been known to us only from the Rural Cemetery beds near Albany which we had referred in Bulletin 42 to the Utica. It is there associated with Diplogr. (Mesogr.) putillus and Corynoideg igo cularis. It is safe to infer on the strength of this form that the Rural Cemetery beds and this portion of the Canajoharie beds be- long to the same horizon. Some layers are profusely covered with the problematicum termed here Cyathodictya? tubularis. This fossil is described in the asp notes at the end of this paper. The fourth series of beds is exposed in a cite reaching from 150 feet above the base to about 270 feet. These beds contain: Cyathodictya ? tubularis nov. er Corynoides calicularis Nicholson (cc) Glossogr. quadrimucronatus mut. cornutus Rued. (cc) Diplograptus (Mesogr.) putillus Hall | (cc) Prasopora simulatrix Ulrich (c) Lingula curta Hall (c) Triarthrus becki Green ete. Calymmene senaria Conrad (r) Ulrichia ? bivertex Ulrich (c) Triarthrus becki, which before had not been noticed, appears in this last division about 40 feet from the base in great numbers. Glossograptus quadrimucfhomeeme mut. cornutus and Corynoitdes calieniaeae EE ee ee ee LOWER SILURIC SHALES OF THE MOHAWK VALLEY 25 were found near the top of this last cliff with which end the out- ‘crops in the Canajoharie gulf. A series of exposures which to a large degree is complementary to the one just described is afforded by the Flat creek ravine at Sprakers, two and one-half miles east of the Canajoharie ravine. The Glens Falls limestone is finely exposed in this section. It is 17 feet thick and consists of thin layers of very fossiliferous lime- stone with shale intercalations near the top and a two-inch con- glomeritic layer at the base, separating it from the Tribes Hill (Fucoidal) limestone. The limestone beds exhibit large ripple marks, small piles of current-swept pebbles and other signs of shallow water conditions. Besides the fossils noted from the Cana- joharie beds, Eurychilina subradiata was. also collected. The “Utica” shale comes in, notwithstanding the shaly inter- calations of the upper Glens Falls beds abruptly as a black shale formation. It contains directly at the base: Diplograptus amplexicaulis (Hall) (cc) Ctenodonta cf. nuculiformis (Hall) | (c) 1 Ten feet above the base abundant Diplograptus (Mesogr.) putillus and ostracods (Ulrichia ? Seeertex, Primitiella unicornis; Primitia ) were observed, which continued through 20 feet, where also layers with great numbers of Leptobolus insignis and limestone bands filled with Dalmanella testudinaria were observed. 2 The beds from 30-60 feet above the base furnished: Diplograptus amplexicaulis (cc) Cyathodictya ? tubularis (cc) Leptobolus insignis (cc) Ctenodonta cf. nuculiformis (c) 3 From 60 feet above base upward there were observed besides: Diplograptus amplexicaulis (cc) Orthoceras sp. Lingula curta | '€e) 4 75 feet above base besides Diplograptus amplexi- caulis and the ostracods, specimens of Clathrospira subconica (Hall) were found. 5 From 110-20 feet Calymmene senaria_ occurs ‘in great abundance and from 125-30 feet fragments of Isotelus and Prasoporas fill the beds. Also at about 135 feet above the 26 NEW YORK STATE MUSEUM base is a bed of abundant small Prasoporas. It is important that this Prasopora, forming here an horizon, has been recognized by Doctor Ulrich as the lower Trenton Prasopora simu- IreaNe tri1 ae | 6 Directly above this bed _ Triarthrus becki ~ begins to be observed in considerable numbers and it continues to be the common fossil through a considerable thickness. | 7 From. 160-80 feet Triarthrus becki, and @ory- noides calicularis are the dominant fossils, while s At 210 feet above base Lasiograptus eucharis appears in great numbers and typical expression. It is associated with: Triarthrus becki, and Lingula curta This association was observed to the top (230 7 apprcnaiee which were found: Sphenothallus angustifolius Hall! (cc) Dalmanella testudinaria (Dalm.) | (cc) Schizocrania filosa Hall (in large specimens) (c} Trocholites ammonius Hall aes Orthoceras sp. . (c) This congeries is typically that observed in the lower “ Utica” shale in the East Canada creek section at Dolgeville and it is nota- ble that also the lithic character of the light drab weathering, blocky, — polygonal breaking, thick-bedded mud-shale is the same as that prevailing in much of the lower parts of the shale at Dolgeville. — We consider it therefore probable that the top of this section is equivalent to the lower part of the Dolgeville “ Utica.” In a new road cut between Flat creek and Canajoharie about 340 feet above base of “ Utica,” hard and thin-bedded black shale was found, containing: Climacograptus spiniferus (filling one bed) (cc) Leptobolus insignis (c) Triarthrus becki (c) Another road cut 40 feet higher and to the north of the former furnished again abundant: Climacograptus spiniferus (c) Diplograptus vespertinus? | (ec) This shale is very strikingly dark and light banded. 1 See Paleontologic notes, p. 74.. 2 See Paleontologic notes, p. 83. 4 —" abe i A ee ee ee eee LOWER SILURIC SHALES OF THE MOHAWK VALLEY 27 The heavy drift to the south has buried the “ Utica” beds as far as the “ Frankfort” beds at the base of the Helderberg escarp- ment. If we combine the observations of Canajoharie and Flat creeks, we obtain the following groups of faunules, indicative of larger zones : 3 meeone of Diplograptus: amplexicaulis, Corynoides calicularis, ostracods, lamellibranchs (notably Pterinea (Prolobella?) trentonensis and menstiet.a, etc.). mueece of Gliossogr. quadrimucronattus cor- nutus, Corynoides calicularis, the ostracods, Cyatho- Merve, Ptriarthrus becki. Mumemeor Lasiogr. eucharis, Lingula curta, meee octania filosa, Trocholites ammo- meems, Lriarthrus becki. meee Gt Climacogr. spiniferus, .Diplogr. Vespertinus, Lasiogr. eucharis, Triarthrus becki The first two zones have never, in our earlier work, been observed in the Dolgeville section, while the base of that latter sec- tion has furnished us a faunule identical with that of number 3. To be sure of the absence of the lower two zones in the Utica region, we have carefully searched the basal sections of the Utica at Dolgeville and Jacksonburgh, three miles west of Little Falls, where Cushing’s map shows an exposure of the contact of Dolge- ville (transition) beds and Utica shale; along the Starch Factory creek at Utica; and the exposure between Holland Patent and South Trenton, recorded by Miller. In none of these localities were any traces of the first two zones of the Canajoharie section found. On Nine Mile creek near South Trenton, where the contact of the @renton and true Utica is exposed, Climacograptus typicalis is the dominant and characteristic graptolite of the basal Utica. This typical Utica graptolite occurs there in immense multitudes. It is associated with: Mastigograptus simplex (Walcott) M. tenuiramosus (Walcott) Pleurograptus linearis (Carruthers) Leptograptus annectans (Walcott) Dicranograptus nicholsoni Hopkinson Glossograptus quadrimucronatus (fall), short, long spined variety Cyathophycus reticulatus Walcott 28 NEW YORK STATE MUSEUM This is the characteristic fauna of the base of the typical Utica. It is the Mastigograptus fauna of Schuchert (I9I0, p. 529). Lasiogr. eucharis appears in great numbers nearby (at ~ Floyd and Marcy) and a little higher up. In the Dolgeville and Jacksonburgh sections which lie halfway between Utica and Canajoharie, the base of the “ Utica” shale (above the Dolgeville transition beds) shows no trace yet of the Canajoharie faunule, but contains: | Glossograptus quadrimucronatus Climacograptus typicalis Lasiograptus eucharis Lingula curta Schizocrania filosa The dominant Climacograptus typitcalis “onuume true Utica is found but sparingly, and Leptograptus an- nectans, Pleurograptus linearis, ime graptus nicholsoni and the Mastigograpti are not ob- served at all in the bed. It is therefore probable that the basal “Utica” at Dolgeville-Jacksonburgh and that at Utica do not represent the same horizons, and if so, the former is probably older than the latter. ) From the assemblage of the facts here presented, we infer that at Canajoharie the two lower zones surely and the others most probably lie below the base of the true Utica and correspond in age to some part of the Trenton. For this older black shale of the — Mohawk valley we propose the term Canajoharie shale. This stage is characterized by the following species: Corynoides calicularis Diplograptus amplexicaulis Diplogr. (Mesogr.) mohawkensis Glossograptus quadrimucronatus var. cornutus Pterinea (Prolobella) trentonensis P. insueta Ulrichia? bivertex Primitiella unicornis ' All these are unknown to us from the Utica shale. A number of . forms as asvogrs eweharis, Du plore put Triarthrus becki, appear in the Canajoharie beds rarely, but become dominant forms in the Utica shale, and others, as the shale brachiopods Leptobolus insignis and Lingula curta, are equally common to both. The true Climaco- : | LOWER SILURIC SHALES OF THE MOHAWK VALLEY 29 graptus typicalis has not been seen in the Canajoharie beds, but is a most characteristic and common graptolite of the Utica beds. | A peculiar feature which we are at present unable to explain is ‘the very frequent occurrence of Diplogr. (Mesogr.) mohawkensis in the Canajoharie beds in the Amsterdam sec- tions and its apparent absence in the Canajoharie sections. Since it is not restricted there to the basal beds only, it can not be assuined that it represents still a lower horizon not represented at Canajoharie. — If the Canajoharie shale is older than the true Utica, it corre- sponds in age to some part of the Trenton. The question then arises, How much of the Trenton does it represent? The fossils of the underlying Trenton and transition shale at Canajoharie (see page 21) are those of the basal Trenton only, and this alone is represented by limestone in the lower Mohawk valley, where it rests on the Amsterdam limestone. The lower Trenton, which is characterized by the Prasopora simulatrix zone and its base by the fauna of the Nematopora beds, is apparently at Canajoharie merged already in the Canajoharie formation, as the occurrence of a horizon with Prasopora simulatrix, rather high up in the Cana- joharie beds in Flat Gulf (page 26) and the evidence of the bryozoan reefs at the base of the Canajoharie would indicate. The Canajoharie beds correspond therefore to at least the lower Trenton. What proportion, if any, of the middle Trenton is in- cluded can not be determined with the data at hand. The typical Canajoharie fauna at Canajoharie indicates as old Trenton as the oldest in the Trenton Falls section. Possibly it contains only lower Trenton but probably it belongs in large part between the lower and middle Trenton. The true Utica is, from present evidence, entirely absent in the lower Mohawk region. We infer this from the faunas of the Cana- joharie shale indicating Trenton age and further from the facts that these black shales pass gradually (as in the Minaville section) into the so called “ Frankfort” or “ Hudson River” shales and sand- stones of the lower Mohawk valley and that these latter have proved to be of an age older than upper Trenton (see Schenectady forma- tion, page 37). 1This conclusion had also been reached by Cumings (title 44, p. 466). 30 NEW YORK STATE MUSEUM j The writer has before cited faunules from the Hudson valley — which contain the characteristic elements of the Canajoharie beds. | The most important of these is that from the Rural Cemetery of © - Albany, whence Glossogr. quadrimucronatus mut. © cornutus was described. It is there associated with i Mastigograptus circinalis Rued. Corynoides calicularis Nicholson . Lasiograptus eucharis (Hall) Diplogr. putillus (Hall) Y | Eopolychaetus albaniensis Rued. Pontobdellopsis cometa Rued. Leptobolus insignis Hall Schizambon ? fissus var. canadensis Ami Hormotoma cf. gracilis (Hall)? shales ” which in the former publications (op. cit. page 36) we have referred to as an eastern development, characteristic of the Appa- — lachian trough, of the Utica shale. | | The belt of Canajoharie beds in the lower Mohawk valley is — abruptly cut off by the Hoffmans Ferry fault which, since the © eastern side has dropped, has buried all lower beds east of the © fault, under a belt of ‘‘ Frankfort” shales and sandstones extend- — ing from the town of Galway in the north across the Mohawk river — to the foot of the Helderbergs. It becomes evident, however, from the facts cited above, that the Canajoharie beds reappear from ~ under this thick mass of overlying “ Frankfort ” shales on the east, along the Hudson, through the Taconic-Green Mountain folding | and they strike there according to this folding to the north-north- — ; 4 ; q This is one of the various upper subzones of the “ Hudson River | east, as indicated by the outcrops at the Rural cemetery and at Cohoes. The stations which we had cited in Bulletin 42 as representing the Utica shale and forming a belt that passes through Albany, are | now mostly to be considered as Canajoharie beds, the same as the _ occurrence at the Rural cemetery, and the few remaining like that _ at Black creek, Voorheesville and the Vly at Voorheesville (title 47, pages 531-33) are black shale zones intercalated in sand- stones and correspond to the “Frankfort” rocks about Schenec- tady. We must infer from these facts that typical Utica is not represented in the Hudson River region but that the Canajoharie shale is directly followed by the “ Frankfort”? (Schenectady) beds. 1 See title 47, p. 528; title 60, p. 37. oe LOWER SILURIC SHALES OF THE MOHAWK VALLEY 31 This is, among others, suggested by an outcrop at Crescent, at the last bend of the Mohawk. At the latter place an anticline brings to the surface (thereby causing the rapids in the river) about 50 feet of “bluestone” (a calcareous sandstone) of the type charac- teristic of the “ Frankfort” (Schenectady) beds, in beds 2-3 feet thick with intercalations of black shale. The latter, however, do not furnish the “ Frankfort” faunule, noted in a later chapter, but Corynoides calicularis Nicholson Cf. Azygograptus ? simplex Rued. Diplograptus putillus Hall Climacograptus bicornis Flall Diplograptus cf. angustifolius Hall Leptograptus annectans Walcott (narrow form) This congeries of forms contains on one hand the Corynoides on account of which we refer the beds to the Canajoharie formation, a reference which is supported by the close position of the outcrops to the belt of Canajoharie beds at the mouth of the Mohawk. It also contains Leptograptus annectans, a species that to our knowledge has been found hitherto only in the basal Utica beds in the neighborhood of Trenton, N. Y., and in the true Utica beds of Cincinnati (title 61, page 265) but the form repre- senting this species at Crescent is not strictly the same as the typical Holland Patent type. The lithologic features of this interesting outcrop also indicate the fact that in the east, the upper portion of the Canajoharie formation may assume the lithologic character of the “ Frankfort’ (Schenectady) beds, a fact that would argue for a direct succession of the two formations in this region. While the Canajoharie shale is eastward in the Mohawk valley cut off by the Hoffman’s Fault, we have found it to reappear north of Schenectady along Alplaus creek and thence the black shales can be traced past Ballston Spa, Saratoga and along the edge of the Precambric to Glens Falls, where they are again cut out by faults. The locality on Alplaust creek has afforded: Corynoides calicularis Glossograptus quadrimucronatus mut. cornutus Lasiograptus eucharis Leptobolus insignis Orthoceras hudsonicum nov.? 1A curious distortion of the old German locality name “ Aalplatz,” eel-place. This species retains in pyritized condition the protoconch and nepionic portion of the shell. See note, p. 113. 32 NEW YORK STATE MUSEUM There can be no doubt of the Canajoharie age of the rock of this Oe outcrop, and yet it is only two miles due north of the “ Frankfort” — outcrops of Rexford Flats, leaving but a narrow strip for a possible © _ belt of intervening Utica shale; and considering the very slight south- west dip of the rocks also but little room for any thickness of the Utica shale. Fine exposures of these Canajoharie ae were observed about — Ballston Spa, especially along Kayaderosseras creek. Here occur: Dicranograptus nicholsoni (tra Glossograptus quadrimucronatus (in some beds large and typical) | (r) Climacograptus spiniferus (ciey Lasiograptus eucharis ed) A similar faunule was observed on the Glowegee, northwest of Ballston Spa, while the single outcrop at Sanne (Carlsbad Spring) contains: Climacograptus spiniferus C. mohawkensis Lasiograptus eucharis Leptobolus insignis An excellent outcrop of the Canajoharie beds between Saratoga and Glens Falls is that at the falls of the Snook kill at Gansevoort, where occur: Glossograptus quadrimucronatus mut. cornutus Diplograptus mohawkensis Lasiograptus eucharis Very important exposures were found above and below Glens Falls. Those above are near the feeder dam, one to two miles southwest of the city and contain: Corynoides calicularis Diplograptus amplexicaulis Glossograptus quadrimucronatus Leptobolus insignis Pontobdellopsis cometa Orthoceras nov. cf. amplicameratum Triarthrus beck Between Glens Falls and Hudson Falls (formerly Sandy Hill) the contact between these shales and the basal Trenton limestone can be observed — or rather could be observed — the feeder dam between the paper mills and the mill races on both sides having LOWER SILURIC SHALES OF THE MOHAWK VALLEY 33 rendered inaccessible the contact exposed in the river bed. This contact was recorded by Mather (title 2, p. 394) as follows: At a little distance below the ferry on the Saratoga shore, at and near the sawmill, the junction of the slate and Trenton limestone, and the gradation of one into the other by interstratification, with the numerous and beautiful fossils, which are intermingled near their junction, can easily be examined when the river is low. The trilobite, the Nuttainia concentrica of Eaton [ Tri- nucleus concentricus (Eaton)], is extremely abundant, and on one specimen of a thin band of limestone six inches square, from the slate, were no less than ten of these trilobites, some of which were entire, and one of the Triarthrus becki. While these transition beds can not be seen any more in place, the construction of the mill race for the Fenimore Paper Mill opposite Hudson Falls has brought to light a great quantity of the transitional rock which has been dumped along the river bank just above the mill. It consists of dirty grayish-brown limestone with black shale seams. The limestone is very fossiliferous; the follow- ing fossils have been noted: Mesotrypa quebecensis (Amz) Schizocrania filosa Hall Dalmanella testudinaria (Dalman) Plectambonites sericeus (Sow.) Triarthrus becki Green Trinucleus concentricus (Eaton) Isotelus fragments The shales at the falls contain: Corynoides gracilis Hopkinson Diplograptus amplexicaulis Hall Climacograptus spiniferus Ruedemann Lasiograptus eucharis (Hall) Trocholites ammonius Conrad These shales can thence be followed about two miles through a fine gorge to the falls at Fort Edward, where there are found: Corynoides calicularis Nicholson Diplograptus cf. euglyphus Lapworth Trematis terminalis (Conrad) ? Orthoceras arcuolineatum nov. From Fort Edward this belt of shale can be followed down the Hudson river for several miles. Occasionally, as in an outcrop two 34 NEW YORK STATE MUSEUM miles south of the mouth of the Snook kill, limestone bands one to two inches thick appear, which are entirely composed of brachiopod, trilobite and crinoid fragments, but collecting will not furnish any- thing but the common brachiopods Dalmanella-testudi-. naria, Rafinesquina, Plectamb oni teggeem| ceus and the trilobite Trinucleus con c@eminaewee The surrounding shales contain: Corynoides calicu- laris, Climacograptus spiniferus, Coupee lus, Lasiograptus eucharis. The last mentioned tome was also observed to fill a band of black shale about three miles up the Snook kill, where it is associated with Trocholites ammonius. | The following inferences in regard to this belt of black shales in : Saratoga county seem of importance for the present inquiry: 1 These shales which have hitherto been considered as good typical Utica shales, are in their lithologic aspect like the latter but lack the strong calcareous admixture and for that reason rarely effer- vesce with acid. But, as we shall show later, they are lithologically quite distinct from the belt of Snake Hill beds, which adjoin them to the east, the latter containing not only numerous intercalations of grit and sandstone beds, as at Snake hill, but being also thinner bedded, more fissile, more argillaceous and less carbonaceous, approaching in their character the Frankfort shale. 2 The fauna of these shales is that of the Canajoharie beds of the Mohawk valley, as shown by the occurrence of and dominance of Corynoides calicularis, Diplograpt ws plexicaulis, Glossograptus quadrimucrona tus mut. cornutus, Lasiograptus eucharis. 3. These shales rest also in this belt on the basal Trenton (Glens Falls) limestone. This relation was observed, as above stated, at Hudson Falls. It may also be inferred from the outcrops on the | Glowegee west of Saratoga, which lie but a short distance south © and in the dip of the belt of basal Trenton (Glens Falls) limestone © passing west of Saratoga through Rowland’s mill and Rock City | Falls. | FRANKFORT SHALE 2 P f nd The type locality of the Frankfort beds is the gorge of Moye creek at Frankfort, about nine miles southeast of Utica. A parallel | series of fine outcrops is furnished by Steels creek, only two miles away, in the so-called Ilion gulf. oe Bie me, - LOWER SILURIC SHALES OF THE MOHAWK VALLEY 35 Investigations of these two sections have shown that both lack the base or the contact with the Utica beds. A comparison with the sections of Starch Factory and Ferguson creeks near Utica indicates that the Frankfort and Ilion sections begin closely above the Utica shale. This is also evident from the fact that on the other side of the Frankfort section only two miles to the east, the Utica shale is still exposed on Fulmer creek south of the village of Mohawk. The strike of the shale in the latter outcrop will carry it to very near the base of the Frankfort and Ilion sections. We found in the rock section at Frankfort which by aneroid is 305 feet thick,t four bands of shale containing fossils. The first of these was collected 15 feet above the base of the section at the foot of a cliff 60-70 feet high. 1 Climacograptus typicalis Hall Lingula fragment Leptobolus insignis Hall Camarotoechia sp. Orthoceras sp. Triarthrus becki Green Trinucleus concentricus (Eaton) The next fossiliferous band was found about 85 feet above the Jase at the second bridge over the creek. Here were obtained: 2 Climacograptus typicalis Hall (large specimens) Prasopora sp. (minute colony) Leptobolus insignis Hall Dalmanella testudinaria (Dalman) mut. Rhynchotrema inaequivalve (Castelnaw) Modiolopsis sp. (fragment) | _ Orthoceras sp. (septum) Triarthrus becki Green Trinucleus concentricus (Eaton) 1Since these beds dip toward the southwest with an angle that locally is ;°, but in general not more than 2°, it is obvious that this figure is too small. Sushing (1905, p. 36) has determined the surface of the Beekmantown to ‘all from Middleville to Ilion at a rate of somewhat over 100 feet a mile, tating that the line of greatest dip runs somewhat more to the westward of his direction. This line of greatest dip would then come near the -direction £ the Frankfort section and since a fall of 100° in a mile corresponds to ut 1° of dip, while the average dip in the Frankfort section appears to be erhaps twice as much, it is safe to assume that at least 200 feet should be dded, but probably a thickness of between 200 and 370 feet, the latter figure orresponding to a dip of 2°. 2 At about the same level is the black shale at the base of the Ilion section (230 feet below the Oneida congo which has furnished: 36 NEW YORK STATE MUSEUM : | n Climacograptus typicalis Hall Leptobolus insignis Hall Dalmanella testudinaria (Dalman) mut. ( sma Dinorthis pectinella (Emmons) Rhynchotrema inaequivalve (Castelnau) Cf. Serpulites longissimus Murchison Triarthrus becki Green where occur: 3 Leptobolus insignis Hall Orthoceras sp. The last fossiliferous shales were found directly below the t (280-305 feet). They furnished: Climacograptus typicalis Hall ot | ! ; | No fossils were observed until about 240 feet above the : Orbiculoidea tenuistriata Ulrich (fide Ulrich) Leptobolus insignis Hall Orthoceras (fragment) Triarthrus becki Green and the Triarthrus becki were found in the shale directl below the Oneida conglomerate. | It is obvious that these small faunules lack the essential elements of the Lorraine fauna and do not appear to consist of more tha an impoverished Utica fauna. We see the strongest evidence of th close faunistic relation between the Utica and Frankfort periods in the uninterrupted persistence of Climacograptus typi calis through the whole of the Frankfort shales. As it will be shown in the next chapter that the beds in the lower’ and probably middle Mohawk valley which have been hitherto re-| ferred to the Frankfort are of much older age, the Frankfort) formation disappearing eastward by overlap and the relations of | the typical Frankfort beds of the Frankfort section westward ané | northward have not yet been studied in detail, it becomes necéssary | to restrict for the present the term Frankfort shale to the formation} as exposed in the Utica region. The formation thus restricted has] its basal limit defined by the top of the true Utica, while the up De: boundary, which in the Utica region is formed by the Oneida con Of these fossils the Orbiculoidea = LOWER SILURIC SHALES OF THE MOHAWK VALLEY 37 -glomerate, is not-yet well defined in regard to the Pulaski formation, the question being to which of the two the shale with Trinucleus northwest of Utica is to be referred. Doctor Ulrich writes that he is inclined to place it with the Frankfort and to confine the Pulaski to the overlying even more fossiliferous arenaceous limestone and ‘shale shown at Pulaski and in the upper part of the Lorraine gorge. The problem of the correlation of the Frankfort formation, thus restricted and defined, with the strata of Ohio has been discussed very fully by Doctor Ulrich and the author. Doctor Ulrich recog- nizes in the Frankfort s. str. the two middle divisions of the Eden shale at Cincinnati, but he is convinced that it also includes the upper Eden. The Eden, as used by Doctor Ulrich for a long time, is confined to beds beginning at the top of the true Utica and extending upward to the base of the Maysville. But as originally defined the Eden included all the shales to the top of the underlying Point Pleasant Trenton limestone in the Ohio valley; hence it in- cluded also the thinning western representative of the true Utica. For this reason Doctor Ulrich has proposed to use the term Eden for a group comprising the Utica and Frankfort (title 69, plate 27). The Eden in Ohio is followed by the Maysville, which in New York is represented by the Pulaski formation and Oswego sandstone. The Lorraine, we infer from the above-cited chart, is retained as a local or New York term only to comprise the Frankfort and Pulaski formations. SCHENECTADY FORMATION j As the black shale belt that follows the Mohawk river from Utica to near its mouth has always been considered as being of Utica age, but has been found to change in age from Utica to lower Trenton in descending the river, thus the parallel and coextensive belt of overlying, more argillaceous, olive gray shales has been quite naturally identified with the Frankfort shale by all authors, the present included, since these beds apparently form a continuous belt, just as the underlying black shale does. When we discovered in the great thickness of “ Frankfort” beds in Schenectady and Schoharie counties the eurypterid fauna associated with a con- ‘siderable number (see page 42) of graptolites, brachiopods, mol- lusks and trilobites, different from those of the Frankfort shale, we distinguished there several thousand feet of sandstones and shales as the “ Schenectady facies” of the Frankfort formation. Closer investigation of the faunas, with the assistance of Doctor } j Ulrich, has led to the conclusion that they are at least as old as” upper Trenton and probably belong mainly between the middle and upper Trenton. We therefore propose to distinguish this | formation as a separate unit under the term Schenectady formation, its type exposures being at the Dettbarn quarries at Schenectady . and at Aqueduct and Rexford Flats near Schenectady. The conclusion of an age older than the Utica for the Schenec- tady formation is supported by, or at once explains, the close con- nection by transitional beds of the Canajoharie beds (which are of lower to middle Trenton age) and these “ Frankfort” beds of the | lower Mohawk valley, as shown in the section about Minaville and along the Schoharie creek. The Utica shale, if it continued down the Mohawk valley, would) have to be found above the Schenectady beds. This inference is | supported by the fact that the latter are overlain by the Indian — Ladder shales (see page 50) which correspond in age to the South- | gate of the Eden group and are but little younger than the true | Utica. If one follows the foot of the Helderberg escapee from the | typical exposures of the Frankfort shale down the Mohawk valley, | one meets but few rather widely separated outcrops of the barren, olive gray Frankfort shales until one reaches the lower Mohawk | valley region, where the rather abrupt widening of the belt and the | thickening of the formation together with the appearance of much | calcareous sandstone (bluestone) combine to change greatly the | aspect of the “ Frankfort” beds. The exact contact plane between | the Frankfort shales that thin out eastward and the Schenectady | beds that rapidly diminish westward, has not yet been established | and may be entirely buried in the deep drift plateau between tnd foot of the Helderbergs and the Utica and Canajoharie exposures | in the lower reaches of the southern affluents of the Mohawk. — The thickness of the Schenectady formation must be very great. | Cumings (title 44, page 466) has already found in the hill back of | Rotterdam a thickness of 1200 feet at least for the “ Hudson River” | beds, for the top of the formation is not there reached. That the thickness of the Schenectady formation is still considerably more, | is proven by the Altamont well-boring. In that well, the drill | started 595 feet below the top of the Indian Ladder beds and passed | through 2880 feet of sandstone and shales before reaching the © Trenton limestone. The shale formations have hence a total thick ness of 3475 feet there. The lowest 1200 feet of this may be } ee hee NEW YORK STATE MUSEUM ne ee ee Figure 2 Schenectady beds at Aqueduct, showing the alternating beds of sandstone (“bluestone”) and shale Figure 3 Nearer view of same quarry face to show irregular deposi- tion of beds : 4 LOWER SILURIC SHALES OF THE MOHAWK VALLEY 39 attributed to the Canajoharie shale, since Cumings (op. cit. page 466) measured 950 to 1260 feet of black shales in the lower Mohawk region and 300 feet at least at the top belong to the Indian Ladder _ beds, a formation that follows the Schenectady beds in this region and will be discussed later (see page 50). There remain then 1800— 2000 feet of Schenectady beds, since we properly assume that “neither the Normanskill nor the Snake Hill beds reach as far west ‘as Altamont. The Normanskill and Snake Hill beds extend con- siderably farther west than their original basin of deposition (see : diagram, page 69) through extensive overthrusting which, however, ‘has not reached the meridian of Altamont where the beds are undisturbed. — _ There are other lines of evidence which indicate a similar great thickness for the Schenectady shale and sandstone. One of these ‘is the width of the belt of shales from Amsterdam to the Helder- _bergs which at the rate of 140 feet dip in a mile, observed for the “Glens Falls limestone, corresponds to a thickness of 1925 feet of shale (13.75 miles by 140), to which must be added goo feet repre- “senting the difference in height of the base of the shales at the north ‘and their top in the south, subtracting from this 2825 feet again the “1140 feet found in that meridian for the Canajoharie shale, we ‘obtain approximately 1700 feet for the Schenectady beds, the Indian Ladder beds having disappeared along the Schoharie creek ‘section. The dips along the line Aqueduct to Schoharie, which are mostly southwest to west and amount to 1°—2°, frequently as much as 5, as at Aqueduct, would also indicate a thickness of more than 2000 feet (2681 feet at 1° dip). _ The cause of the astonishing thickness of the Schenectady shales is to be sought in their deposition in a basin, namely, the sinking foreland in front of the rising Green Mountain folds to the east; which basin was rapidly being filled with sediments. The shallow water origin of most of the shales and sandstones of the Schenec- tady beds is proven by the sun-cracks found in the thinner sand- ‘Stones (as at the Bozen kill), the frequent layers of mud pebble beds,’ cross striation with plunge structure, very rapid change of thickness of beds and other features. 1These mud pebble layers occur mostly on top of the sandstone beds, when the latter are followed by argillaceous shales, indicating that the first clay deposits were rolled about by the waves upon the sand and formed into mud balls. 40 NEW YORK STATE MUSEUM The rocks of the Schenectady formation contain a much greater amount of sandstone beds than the other shale formations of New — - York. Much of this sandstone occurs in thick banks, is somewhat calcareous and much quarried as “bluestone.” The hundredfold — alternation of these sandstone beds with the shales which persists — to a more or less extent throughout the whole formation is the most notable lithic character of the eastern development. Numerous sections which show these endless alternations of sandstone which, on account of its often coarse nature, is cited as grit, with slate, have already been published by Mather in the First District Report | (pages 375-79), from the lower Mohawk and from Schoharie ~ county. We insert here as example a section which we have measured in the abandoned quarries and the river bank at Aqueduct and Rexford near Schenectady, in descending order: a | : 1 Argillaceous shale [2) ==) 2 Grit banks, about 1 foot thick with shale intercalations Y foot thick Oo == 25 3. Shale, argillaceous 14" == ae 4 Gat ¥ 6” = 2 8” ; 5 Dark argillaceous shale 13’ == 350" 6 Grit 6" == "307 ae 7 \ohale : a) Sa 8 Compact grit 6! == 4723 9 Shale 2! == aaa 10 Calcareous grit (“ bluestone ”’) 2 == ieee tt Dark argillaceous shale 8! == eae 12 Grit bed 6° == eae 13 Dark shale, separated by fault from underlying beds 3 =a oy tA GCE 6" ==" hee 15 Shale, dark, argillaceous 2' = 65 am 16 Thin bedded grit I 6 = 66" gr 17 Bluestone i. 71 8" 4 “18 . Shale | A 73 "4 | 19 Bluestone 1' 6 ==. ae 20 Thin alternating beds of grit and shale, . banded and wavy 2! == 9 21 Compact beds of bluestone, with a few thin discontinuous shale seams. Beds irregular | 9 6 == eae 22. Shale ; 4 6 == G17 23 Grit band with distinct plunge structure 6" == eg 24 Shale, dark, argillaceous 2' 6! == 70a 25 Carit bed with one shale seam 3' 6 == er ee 26 Shale, soft dark gray to black argilla- : ceous and sandy shales - Oo! | == 167-5. LOWER SILURIC SHALES OF THE MOHAWK VALLEY AI The constant alternation of more or less coarse sandstone with shales is indicative of a frequent shifting of the conditions, presum- ably through currents, either reversal (tidal) or continuous currents. | There is sometimes clear evidence of absolutely regular or rhythmic shifting. Such a place was for instance observed in an abandoned quarry on the Bozen kill between Altamont and Delanson. The base is here formed by a compact bed of sandstone some 15 feet thick. This sandstone is abruptly followed by dark argillaceous shale in which higher up thin sandstone layers appear, that become more frequent until another thick sandstone bed is formed, like the basal one. This in turn is cut off by a shale, that gradually yields to sand. The whole cycle is in this place repeated three times, shales and sandstones being each of equal thickness, the whole in- dicating a most remarkable regularity of change of deposition which on account of the very shallow water character of the rocks of that locality, may well have been a condition due to reversal or tide currents. ine It agrees well with the evidence of the shallow water or shore Origin of the Schenectady shales and sandstones, that they are often densely filled with remains of seaweeds (Sphenoph yous Matifolius Hall). In contrast to the Frankfort shales the Schenectady beds have furnished a large fauna, although they had hitherto currently been held to be quite barren. Altogether about 70 species have been found and there appears to be no striking difference in the lower and upper faunas of this great mass of rocks, aside from that of the Indian Ladder beds, which have been separated as a distinct formation. The following are the faunal lists from the principal localities. The easternmost outcrops which represent very low beds of the formation are those at Aqueduct and Rexford Flats, three miles northeast of Schenectady; these have afforded the following asso- ciation of species: Sphenophycus latifolius (Hall) as Gees Azygograptus sp. nov. (r) Mastigograptus cf. simplex Walcott (fragment) CCE) Climacograptus typicalis Hall (c) Diplograptus vespertinus Rued. (c) Lingula rectilateralis Emmons (rr) Leptobolus insignis Hall (c) Rafinesquina alternata (Conrad) (small) (c) Serpulites (rr) a NEW YORK STATE MUSEUM : Cyrtolites sp. (very young example) (rr) Trocholites ammonius Conrad a Cyrtoceras sp. nov. 7 (r) Spyroceras bilineatum (H all) (rr) Triarthrus becki (Green) (ry Isotelus cf. gigas Dekay' - : (rrp Primitia (minute form) (cc) Eurychilina | (r) Pterygotus prolificus Clarke & Ruedemann P. nasutus Clarke & Ruedemann A much larger collection was obtained two miles farther south- west in the bluestone quarries at the northeastern outskirts of Schenectady, notably the Dettbarn quarry. This has afforded: Sphenophycus (Hall) (cee) Mastigograptus sp. nov. Tl Climacograptus typicalis Hall -Lasiograptus eucharis (Hall) Crinoid joints Leptobolus insignis Hall Lingula rectilateralis Emmons Dalmanella testudinaria (Dalm.) (small) Conularia trentonensis Hall var. multicosta nov. Modiolopsis cf. modiolaris (Conrad) Saffordia ulrichi nov. Cyrtoceras sp. nov. Spyroceras cf. bilineatum (Hall) Trocholites ammonius Conrad (small) Triarthrus becki Green Trinucleus concentricus Eaton Eurypterus pristinus C. & R. _ E ? (Dolichopterus) stellatus C. & R. Eusarcus triangulatus C. & R. E ? longiceps C. & R. Dolichopterus frankfortensis C. & R. D. latifrons C. & R. Hughmilleria magna C. & R. Pterygotus ? nasutus C. & R. Pi protimneus (CS Kk: Stylonurus ? limbatus C. & R. The next series of outcrops which, on account of the southwes dip of the beds, are probably a little higher in the Schenectad formation, are those at Rotterdam Junction. Prosser and Cumings have described (title 33, page 658) a small section nine-tenths of 1 This is a large complete individual 6.5 inches long, from the “ bluestone. LOWER SILURIC SHALES OF THE MOHAWK VALLEY 43 mile west of the Schenectady pump station, from a deep glen and a long cut on the West Shore Railroad. This section is as follows: Feet I C1 Covered from level of Mohawk agent. tle canal... os ca u5s 4 25. 25 C 2 Fine shale which at the base of the glen does not weather readily to soil. Graptolites are PAEIA WE ARISE win oa 2a > ols -." a3 135 C 3 Very fragile shale exposed in the epee OM Oe. Sie stad o Bele C2 187 See hin sandstone layer .... ..... ..° 2/<4a== US nk in aieloinie anes oss a 2% ay L 5/2] es ales me. sin layer of sandstone:........ -C 7 Crumbling arenaceous shale ..... 3 5/12==152 C8 Heavy layer of sandstone by the highway which runs under the railroad track east of the cut... 2—— 156 The following fossils are recorded “from a very thin layer of loose-grained, arenaceous shale exposed near the base of the rail- road cut on both sides of the track and largely composed of the comminuted fragments of fossils ” 1 Triarthrus becki Green (c) Numerous small fragments of the pleurae and a few complete specimens of the glabella 2 Trinucleus concentricus Eaton (c) Mostly fragments of the spines and cheeks 3 Plectambonites sericeus (Sowb.) H. & C. (?) (c) All the specimens are very small and rather coarsely striated. Dalmanella testudinaria (Dalm.) (r) Orbiculoidea sp. Monticulipora (Prasopora) lycoperdon Say (?) (r) Crinoid segments (r) Graptolites CONT Cyn Cumings (title 44, page 45,) has later described a fine section exposed in a ravine on the northeastern slope of Waterstreet hill. This is as follows: 21 Rotterdam section ( Near the railroad arch in the bottom of the creek 8 feet of very thin, fragile, dark grayish to bluish black, argillaceous shales with occasional very thin sandy layers, one near the middle of the stratum being about 1 inch thick............. 8 =8 44 NEW YORK STATE MUSEUM I? Heavy, compact sandstone of grayish to greenish blue color, weathering gray to brown........ 10: == ae I? Mainly grayish, friable shales with thin layers of sandstone. . |) uc. fteepamens ache eae eae 12’ = 30’ I* Heavy sandstone with intercalated shale........ > "Osa [> Dark ‘crumbling sshaleeeoe eee oe ego I® Shale with mainly thin, but some heavy layers of sandstone J 50 elses ee ee 27 =e I? Heavy stratum of sandstone....... yop 4 == 85 I® Shales with some thin layers of sandstone....... It == 100m I® Thick to thin and broken layers of sandstone.... I0’==110 ['- Fine’ shale. 22.42 ee ef 1 I*? Thin broken sandstone with crumbling shale..... 45 == 16a T1?. Shale... Joncw ce abihets Steet ee OY 08 5’ == 505m I?3 Thin sandstone and shale. Base of high waterfall. 5 ==170 I?* Thin friable blackish shale by excavation of which from beneath the sandstone above, the fall has béen formed ns Woe Sere 2 ee Or 12’ == 18a8 I? Two layers of massive sandstone over which the water falls: 4 yi aaa topes ce ee 8’ == 19008 [*¢: Thin sandstone ‘layers: 7.0 282 ¢s4 2 2' ==19m ifs Clear dark-shale-e ron Gs errr eer 4’ ==.1969 I** Apparently heavy-bedded sandstone weathering to thin often: lenticular’ divisions... 22.5 oe 25 == 228 i*? Shales and thin sandstones: * 7... 2-4. 10 236 1?° Medium thick layers of sandstone with massive 2 foot layer at base and some thin beds of shale, on | and shaly partings.) 2.466 (4 gs .s0 eee 39’ == 27098 I®* Mostly covered. Highly inclined layers of ae stone exposed in the creek banks 120 feet above ~ | No, 26) 0 kes Siw CR Ss ae, 120’ == 390% | I*? Covered to top of hill but with an occasional ex- | posure of sandstone. 680 feet by barometer... 680’ == 1070 We have carefully collected in this splendid section and found the | following fossils: | In I? Climacograptus spiniferus Ruedemann (c) Eurypterid fragments taps Climacograptus spiniferus Ruedemann (c) Leptobolus insignis Hall Eurypterid fragments wen : In I*! Sphenophycus latifolius (Hall) (c) | In [3 Eurypterid fragments In 1° Sphenophycus latifolius (Hall) In [°° Sphenophycus latifolus (Hall) | (cc) Callograptus multiramosus nov. . (ma Rhytimya sp. (rr) | Eurypterus megalops Clarke & Ruedemann (rr) } LOWER SILURIC SHALES OF THE MOHAWK VALLEY 45 Eusarcus triangulatus C. & R. i (r) Dolichopterus frankfortensis C. & R. (c) Hughmilleria magna C. & R. (c) Pterygotus prolificus C. & R. (c) In following the dip of the rocks, a long series of outcrops were found beginning at Duanesburg, about ten miles west-southwest from Schenectady, and extending about four miles along the rail- road to Delanson. The dip is too small to measure accurately, dif- ferent measurements giving from 1° to 2°, but it is safe to assume that these outcrops which are halfway between the lower beds at Schenectady and the top of the formation at the Helderbergs are 1000 feet above the base. In a bluestone quarry just above the station at Duanesburg about 40 feet of thicker and thinner, partly coarser sandstone beds with intercalated gray, argillaceous and often also arenaceous shales are exposed. The sandstone beds are distinctly lenticular, rapidly thin- ning out and swelling up in the quarry face and carrying numerous mud pebbles near their surfaces. The shaly layers show fine cases of mud-flow and the whole character of the beds indicates a rather shallow, current or wave-swept sea. The shale seams are profusely filled with seaweeds and fragments of eurypterids. The following species were obtained: Sphenophycus latifolius (Hall) (cc) Climacograptus bicornis Hall ‘Cam Ss. Camarotoechia sp. fragments Dolichopterus frankfortensis Clarke & Rued. ee) Eusarcus triangulatus C. & R. (c) Stylonurus ? limbatus C. & R. (r) Hughmilleria magna C. & R. (c) Pterygotus prolificus C. & R. (c) P. ? nasutus C. & R. (r) The beds can be followed along the Schenectady branch of the Delaware & Hudson Railroad in a continuous exposure to Delanson, without any change in lithic or faunal character. Following then the southwest dip no outcrops are met with until the Schoharie valley is reached, where a number of small exposures are observed in the river bank above Schoharie Junction. These represent the uppermost portion of the Schenectady beds and can not be more than 300 feet below the top, or the boundary with the Brayman Shales in the hills to the east and west of the valley. The beds are still the same alternating thick impure sandstones and dark gray to 46 NEW YORK STATE MUSEUM black shales. It is, however, obvious that the sandstones have become more silicious and are prevailingly gritty, often coarse and assuming the character of an arkose, as notably at Duanesburg. _ The top layer of the sandstones sey contains numerous mud pebbles inclosed in the sandstone. The following fossils were collected along Schoharie creek: Sphenophycus latifolius (Hall*) . (ry Climacograptus typicalis Hall (c) Taeniaster schohariae nov. (rr) Conularia trentonensis Hall var. ane nov. (ri Eurypterida: Dolichopterus frankfortensis; Pterygotus sp. While in the Schoharie valley the Schenectady beds can not be followed to their contact with the overlying Brayman shales, this can be done along a small northern branch of the Cobleskill between Central Bridge and Howes Cave, which has been pointed out by Grabau (title 56, page 102) as an excellent exposure @f-tmem Brayman shales. Here about 120 feet of Schenectady shales and sandstones are exposed in the ravine above and below — the road. The lower portion consists prevailingly of dark gray to — brownish green, sandy shales with black argillaceous shales in thin- ner seams. These change upward into purely sandy shales, which © grade into a sandstone about 20 feet thick that is followed by the Brayman shale. The lower shales furnished great quantities of Sphenophycus latifolius and many ieaemiemm of eurypterids, among these chelicerae of Pterygotus, and cara- paces of Pterygotus prolificus, Eury pee pristinus, Dolichopterus cf. frankegeeeeeee sis and Hughmilleria ci. magna. These Garggeue remains could be traced into the bottom of the topmost sandstone bed. Thus we see that here the eurypterid fauna indicative of the Schenectady formation reaches close to the Brayman shales which are supposed to be of Upper Siluric age (see postea page 54). Another series of outcrops of the middle and lower Schenectady formation is found along the Schoharie creek from Central Bridge 1 This is the type locality of the species. Hall states of the occurrence of the latter: “This species occurs in considerable abundance near Schoharie, in the bed of the creek, in the central part of the Hudson River group. ] have not seen it in any other locality.” We have not been able to find Gebhard’s old locality at Schoharie, but as is seen from the lists, have observed this remarkable seaweed in sometimes immense quantities in other outcrops, as at Kellum’s quarry near Schenectady ei in the Rotterdam Junction section. LOWER SILURIC SHALES OF THE MOHAWK VALLEY 47 to Fort Hunter, at the mouth of the creek. About seven and one- half miles south of Fort Hunter the contact of the Canajoharie shale with the Schenectady is a very distinct one. The section at this contact in a cliff on the western side of the creek, three miles south of Mill Point, has been described by Prosser (1900, page 470), as follows: ) ; ; - Feet _ 45X* Clear black shale from the water to the base of lowest sandstone stratum in the cliff, 114’ by level and 105’ by barometer. At the sand- stone stratum there is a decided lithologic break from the black argillaceous shales be- SS SUT ES 2) Cee ee senate Ti4 == 1I4 X? Grayish sandstones alternating with bluish argillaceous shales to the top of the cliff. Padeen: River fottmation........../:-...- 195 = 309 X* Mostly covered from the top of the cliff to MUIR Sis asa ss adhe Sa 0s See 15 == 324 X* Occasional ledges of sandstone show on the side of the hill from the highway nearly to @= cop. -Ludson Raver formation........... 120 = 444 From this point up the river a splendid series of exposures of the Schenectady formation is furnished by the river banks. The section from Burtonville (formerly Burton’s bridge) to Esperance has already been described in detail by Mather (title 2, page 379). _ Hundreds of feet of rock are here exposed in magnificent cliffs; on investigation they prove, however, a monotonous alternation of sand- stone or grit beds with shales with an extreme scarcity of fossils. As far as fossils were observed (a few traces of Climacogr. ty picalis inthe upper layersand Sphenophycus lati- folius in the lower shales), they show the great uniformity of the fossil content throughout the entire series of beds here com- prised as Schenectady shale. A third group of fossiliferous outcrops has been observed by us five to ten miles south of Schenectady, directly in front of the Helderbergs, along the Normanskill and its branches, the Bozen kill and the Vly near the villages of Altamont, Guilderland and Voorheesville: We have already described on page 41 the remark- able alternation of sandstones and shales at the Bozen kill. Con- tinuous outcrops ranging through 200 and 300 feet of rock are found in the upper branches of this kill west of Altamont, which form deep ravines in the lower slope of the Helderberg escarpment. ‘These beds consist prevailingly of bluish and greenish gray shales with several intercalations of sandstone beds, the latter reaching 48 NEW YORK STATE MUSEUM 15 feet in thickness. The beds are nearly barren; only a few frag- ments of eurypterids were found in the lowest portion. More fos- siliferous proved the excellent exposures along the Vly beginning ee en a —" at the fall a mile below Voorheesville. These beds are from 500— — 600 feet or more from the base of the Upper Siluric beds (Manlius waterlime) of the Helderbergs. The beds of that section are at the western edge of the Appalachian folds-of the slate belt of New York and still slightly disturbed by small folds and some overthrusts of probably small throw. The upper beds of this section, which comprises about 200 feet, consist of fossiliferous black to grayish ~ argillaceous shales with several sandstone intercalations and the lower beds of black shales with but few and thin sandstone beds. These shales, of which 80 feet are exposed in the steep eastern bluff of the creek, were formerly referred by the writer (title 47, page 532) on account of their lithic character and fossil contents to the Utica shale. We have now a much larger fauna from this section | at our disposal which, with our present knowledge of the shale © faunas, throws a different light upon the question of the age of — these shales. The latter contain: Diplograptus vespertinus Rued. (c) Diplograptus (Mesogr.) putillus Hall (cc) Climacograptus typicalis Hall (c) Leptobolus insignis Hall (r) Minute individuals of Rafinesquina Pterinea (Prolobella) trentonensis Conrad (r) Orthoceras sp. nov. (“Endoceras proteiforme ”’) (c) Lepidocoleus jamesi H. & W. (r) Primitia sp. The sandstone layers of the upper portion have furnished: Climacograptus typicalis Hall | (c) Hughmilleria cf. magna C. & R. (r) An excellent section leads from these beds up to the Upper Siluric along a branch of Black creek at the Indian Ladder. The beds here exposed have furnished a different fauna and are described further © on (p. 50) as Indian Ladder beds. The combined faunal list of the Schenectady formation is: Sphenophycus latifolius (Hall) Dictyonema multiramosum nov. Azygograptus sp. nov. Mastigograptus nov. cf. ni atts Walcott: M. sp. nov. I GOS te Di a oF nly, gis ie ae eg ntmin < ‘aaoqe Spoq Ape oudYyIS ‘aseq je ayeys oiseyoleuey “Yyao19 al1eyOYyIS uo Wyo Sesoq Pv sInsLy RMR ARE TR NSS ENT A tI TINT eT 6 ae, ~ LOWER SILURIC SHALES OF THE MOHAWK VALLEY 49 Diplograptus vespertinus Rued. Climacograptus bicornis mut. ultima nov. C. typicalis Hall Lasiograptus eucharis (Hall) Crinoid joints Taeniaster schohariae nov. -Lingula rectilateralis Emmons Leptobolus insignis Hall Dalmanella testudinaria (Dalman) Rafinesquina ulrichi James (typical) Plectorthis plicatella Hall Orbiculoidea sp. Conularia trentonensis Hall var. multicosta nov. Serpulites sp. Saffordia ulrichi nov. Cyrtolites cf. ornatus Conrad Cyrtoceras sp, nov. Spyroceras bilineatum (Hall) Trocholites ammonius Conrad Triarthrus becki (Green) Isotelus gigas Dekay Trinucleus concentricus Eaton Primitia 3 Eurychilina cf. subrotunda Ulrich Eurypterus pristinus Clarke & Ruedemann } | 4 megalops C. & R. ? (Dolichopterus ?) stellatus C. & R. a... triangulatus C. & R. E ? longiceps C. & R. Dolichopterus frankfortensis C. & R. D. latifrons C. & R. | ‘ Hughmilleria magna C. & R. Pterygotus nasutus C. & R. Stylonurus ? limbatus C. & R. The dominant elements of this large fauna are certain Canajo- hharie and Utica shale species on one hand, and the eurypterids on the other. The former elements are the species of Mastigograptus, Diplograptus vespertinus, Climacograp- Memeetypicalis, Lasiograptus eucharis, Lep- Mebpolus insignis, Trocholites ammonius’ _1The eurypterids are described and figured in the forthcoming Memoir on the Eurypterida of New York by Clarke and Ruedemann. ~#Trocholites ammonius Hall is a form that probably occurs entirely or mainly below the Utica in the Canajoharie shale. Its type locali- ties (title 3, p. 309) are the East Canada creek, Canajoharie and Cold- Spring, all three localities of shales older than the Utica. 50 NEW YORK STATE MUSEUM and Triarthrus beck1. These are also theaiegegeee quent species, and the entire fauna receives thereby a distinct Cana- ~ joharie-Utica aspect. But we also note in the congeries of forms ~ a number of species that are not observed in either the Canajoharie or the Utica, but are known only from the Trenton. Such spe-™ cies are Lingula rectilateralis , \G@eaaeeeeeee trentonensis, Spyroceras bilinea ttt. nucleus -concentricus, Eurychili#@ageeee mainly the evidence from these fossils that indicates the Trenton age of the Schenectady formation. Finally there is a strong ele-~ ment of entirely new species, giving the Schenectady beds a distinct character of its own; this element consists of a few rare species, © as Dictyonema multiramosum, “Tacagaeoee schohariae, Saffiordia ulrichi, “and? Sespequuem of the eurypterids. It is true the E.ch in @@ mia clevelandi Walcott, of the Utica shale of Holland Patent; N. Y., may be contained in this Schenectady fauna, and thus also’ one eurypterid at least be a Utica element, but there is still no doubt that the eurypterids of the Schenectady beds constitute a strong” distinctive feature from the Utica fauna as known to us at present. If we attempt to compare this formation with others outside the State, we find similar shale beds of upper Trenton age in the lower third of the Martinsburg shale (title 62, page 62) m Penney sylvania, extending thence probably into the Martinsburg shale of New Jersey and south into Maryland. | INDIAN LADDER BEDS The best section known to us leading from the Schenectady beds up to the Upper Siluric beds, is along the upper left branch of Black creek forming the fall and deep ravine at the Indian Ladder near Meadowdale, Albany county, N. Y. The section comprises about 410 feet (aneroid measurement), of which the lowest 100 feet are dark gray to black argillaceous shales with two thick sand- stone bands (each about 4 feet), while the next 100 feet are of a character not met with in other outcrops of the Schenectady beds. They consist of rapidly alternating dark gray shales and thin rusty looking, somewhat calcareous sandstone layers, % to I inch or more thick. The uppermost part of this portion becomes quite sandy. Nearly 100 feet are there covered, while some 120 feet at the top consist of prevailingly heavy sandstone beds with inter-__ calated dark arenaceous and argillaceous shales, and an occasional LOWER SILURIC SHALES OF THE MOHAWK VALLEY 51 thin limestone band. The top is formed by a white hard sandstone bank 3% feet thick and consisting largely of rounded sand grains. This is separated by shale, one layer of which consists of pyrite, from an underlying gray sandstone bed, also composed of rounded grains. The sandstone beds of this upper part of the formation are extremely irregular courses; in one case a bed was seen to run out within 10 feet from 4 feet to 1% foot. These beds present an extremely barren aspect; the only observa- tion of fossils in them of which we are aware is that by Walcott (title 17, page 345) who states: “ The only fossils I found at this maoeaity were Orthis testudinaria and Trinu- Stems concentricus.” Very thorough search has furnished us a small graptolite faunule in the shales of the lower 200 feet and another faunule in the thin calcareous sandstone inter- calations of the second hundred feet. A few bands of the latter proved to be covered with the remains of a microfauna, especially small crinoid joints. The shale has furnished: Dictyonema arbuscula Ulrich : (r) Diplograptus peosta Hall (r) Dicranograptus nicholsoni Hopkinson (typical) (rr) The sandstone contains a pronounced microfauna which has been kindly determined for us by Doctor Ulrich as follows: 1 Columns and calyx plates of a cystid allied to Cheirocrinus (r) 2 Very pentagonal columns 3. Small Heterocrinus columns (cc) 4 Callopora nealli (James) Ulrich 5 Arthrostylus tenuis Ulrich 6 Helopora n. sp. 7 Rhinidictya cf. parallela (James) 8 Rafinesquina ulrichi (James) (cc) g Plectambonites nov. (= centricarinatus nov.) (c) 10 P. plicatellus (Ulrich) Ir Dalmanella multisecta (Meek) (c) 12 Lepidocoleus jamesi (Hall & Whitfeld) (c) 13 Ceratopsis chambersi (Miller) (typical) ‘ie 14 Trinucleus bellulus Ulrich (c) 15 Acidaspis crossota Locke (c) 16 Calymmene (Cincinnati Eden species) We also had a Tentaculites cf. flexuosa Hall, a small Hyolithes, fragments of Ceraurus pleurexan- 52 NEW YORK STATE MUSEUM themus Hall and small cranidia of a Dalmanites (Pterygo- metopus). Doctor Ulrich has determined the horizon as corresponding to ‘the lower third of the Oe shale of the Eden group at Cincin- nati. A comparison of the fossil list here given with that of the Schenectady beds shows at once that the “ Frankfort ” beds of the lower Mohawk valley contain two distinct faunas. The beds at the Indian Ladder also differ in their lithologic aspect; it is there- fore safe to distinguish them as.a separate unit, for which the name Indian Ladder beds 1s here proposed. The Indian Ladder fauna is markedly distinct from the Schenec- tady fauna in the absence of all the dominant forms of the latter, as notably the eurypterids, Climacograptds) tee calis, Triarthrus-becki; Trocholit@s eq. nius and the seaweeds. It consists on the other hand of a congeries that has hardly any members in common with the Sche- nectady beds. Much of this is clearly due to a different facies or different marine conditions, at least in the contents of the rusty lime- stone bands; for instead of the mud-loving linguloids and lamelli- branchs of the Schenectady beds, we find here the strophomenoids and orthoids, indicating clearer water. The novel element of this faunule is represented principally by bryozoans, brachiopods, the ostracod Ceratopsis chambersi and the trileies (Acidapsis eTross of a} Trinweteds bellu- lus) and the reappearance of such Trenton forms as Dalmanites callicephalus and Cera pleurexanthemus. Also the graptolite faunule of the shale is totally different from that of the Schenectady beds. In Dicranograptus nicholsoni it contains an upper Trenton and lower Utica element, that here reappears after a long interval, in Diplograptus peosta,. the first) fore runner of the Lorraine fauna andin Dictyonema arbus- cula, a form of the middle Eden shale of Ohio. The combined evidence. of the whole fauna is that the Indian Ladder beds are. younger than the Schenectady beds, not a mere different facies of the same, but still older than the typical Lorraine. The horizontal extension of the Indian Ladder beds in the expos- ures at the base of the Helderberg escarpment seems to be but very restricted. In the section obtained along the roads south of Altamont, only four miles west of the Indian Ladder, . ee a ee Gadde teat — FS m Zz =i — ——— ed ee E <= a = = a EEEEAZEZZ OY DIN) > SS is se0pOT Dip ya FYVHOLVNVO STIV4 NOLNSYL OoNvV TANNVHO SIAS1 NISVG@ AdVLOSNSHOS S14 SVLiT NMOLYSIWM LOWER SILURIC SHALES OF THE MOHAWK VALLEY 69 Note to diagram Doctor Ulrich and the writer have represented the stratigraphic results here obtained in the adjoined diagrammatic section of the Eopaleozoic formations of the Mohawk valley. The relations of he formations below the Trenton are reproduced as established through former investigations by E. O. Ulrich, H. P. Cushing and the writer. The relations of the Canajoharie and Schenectady beds to the Trenton limestone of the Trenton Falls basin are represented as described here. The upper Trenton limestone is drawn as abruptly terminating at the eastern edge of the Trenton Falls basin, Because Doctor Ulrich failed to find it between Rathbone brook and Middleville, and the Utica shale is shown to diminish rapidly eastward, especially in its lower portion. The amount of its east- yard extension in the Mohawk valley at present is not fully known. The Schenectady beds may at their top reach into the upper Trenton we and this transgression into the upper Trenton is indicated by the dotted line. The Indian Ladder beds appear as a lenticular body, since their main extension is in northeastern direction, crossing the east-west sectional plane in a very limited area. Doctor Ulrich holds from his investigations that the Levis is the second trough east of the Schenectady basin and that the Chazy bay intervenes but is now covered by the overthrust Levis deposits. We have not attempted to introduce this condition on the diagram 9 the right of the permanent barrier because the exaggeration of the vertical scale would not permit its intelligible representation. e overthrust condition, however, which has brought the forma- on of the Levis basin in contact with those of the Schenectady basin in Albany and Saratoga counties, is indicated by the arrows showing the direction of the movement. We have further tenta- tively placed in the series of the Levis channel formations (mainly graptolite shales) a limestone outcropping about Bald mountain. From fossils collected last summer by the writer it is determined as of upper Beekmantown age. The Rysedorph Hill conglomerate, Which also outcrops at various localities, belongs with the Levis channel graptolite beds and probably lies between the Normanskill shale and Snake Hill beds. . Bibliography (1) 1842 Vanuxem, Lardner. Geology of New York; Report on the fi Third District. (2) 1843 Mather, W. W. Geology of New York; Report on the First District. % a: 70 (3) (4) (5) (6) (7) (8) (9) (10) (11) (20) (21) (22) 1847 1858 1865 1873 1877 1879 1882 1883 1885 1889 1890 1893 NEW YORK STATE MUSEUM Hall, James. Palaeontology of New York. v. I. Billings, E. On the Asteridae of the Lower Silurian Rocks of Canada. Can) Org. Remvams: “Dec: Vil ayes Billings, E. Geology of Canada, Palaeozoic Fossils. vy. 1. Meek, F. B. Descriptions of Invertebrate Fossils of the Silurian and Devonian Systems. Rep’t, Geol. ie Ohio. Ve Epes Whitfield, R. P. In Lieut. G. M. Wheeler’s Report on U.S. Geog. Surv. West of tooth Meridian... v. 4, Pal., p. 19-20 Ulrich, E. O. Descriptions of New Genera and Species of Fossils from the Lower Silurian. about Cincinnati. Jour. Cincinnati Soc. Nat, Hist. vvi2) Walcott, C. D. The Utica Slate and Related Formations of the Same Geological Horizon. Albany Inst. Trans. 10. I-17. Walcott, C. D. Fossils of the Utica Slate. Albany Inst. Trans, 10 2o; Miller, S. A. Description of Two New Genera and Eight New Species of Fossils from the Hudson River Group, with Remarks upon Others. Jour. Cincinnati Soc. Nat. Hist. 5:34. Whitfield, R. P. Geology of Wisconsin. v. 4, Paleontology. Beecher, C. E. List of Species of Fossils from an Exposure of the Utica Slate and Associated Rocks within the Limits of the City of Albany. 36th Annual Report N. Y. State Mus. Nat. Hist. p. 78. Ford, S. W. Age of the Slaty and Arenaceous Rocks in the Vicinity of Schenectady, N. Y. Amer. Jour. Sci. 29:397—-99. Ulrich, E. O. Contribution to Canadian Micro-Paleontology, pt II. Stiirtz, B. Bietrage zur Kenntniss palaeozoischer Seesterne. Palaeontographica. 36:234. Walcott, C. D. Value of the Term “ Hudson River Growl in Geologic Nomenclature. Bul. Geol. Soc. a | 15335) 57- Hall, James, & Clarke, J. M. Palaeontology of New York, | Vero, pt. i Beecher, C. E, On the Thoracic Legs of Triarthrus. Amer. Jour. Sci., Ser. 3, v. 46, 1893; also Amer. Geol., v. 13, 1804; Amer, Jour, Sci Ser.(3, v- 47, 1804; Amen Geol., v. 15, 1895; Amer. Jour. Sci., Ser. 4, v. 1, 1896. Clarke, J. M. The Preeeeonch of Orthoceras. Amer. Geol. | I2:112. : Matthew, W. D. On Antennae and Other Appendages of Tri arthrus becki. Amer: Jour. Sci., Ser. 3) sam Ulrich, E.O. New and Little Known Lamellibranchiata from — the Lower Siluric Rocks of Ohio and rise. si : Rep’t, Geol. Sur. Ohio. v. 7. (23) 1894 Clarke, J. M. The Early Stages of Bactrites. Amer. Ged | 14:37. | 9) 1895 1896 1807 LOWER SILURIC SHALES OF THE MOHAWK VALLEY 71 Darton, N. H. Preliminary Report on the Geology of Albany County. 13th Annual Report N. Y. State Geologist. 1:229-61. Darton, N. H. Geology of the Mohawk Valley. 1: Herkimer, Fulton, Montgomery and Saratoga Counties. N. Y. State ‘Geol. Rep’t 13 (for 1893), p..407. Hyatt, Alpheus. Phylogeny of an Acquired Characteristic. coc: Amer. Philos. Soc. 32; no. 143) Ruedemann, Rudolf. Development and Mode of Growth of the Genus Diplograptus, McCoy. N. Y. State Geol. Rep’t 14 (for 1894), p. 15, 217. Ulrich, E. O. Lower Silurian es of Minnesota. Geol. Minn. v. 3, pt 1, Paleontology. Winchell, N. H., & Schuchert, Charles. The Lower Silurian Brachiopoda of Minnesota. Geol. Minn., v. 3, pt 1, Paleon- tology. | Harper G. W., & Bassler, R. S. Catalogue of the Fossils of the Trenton and Cincinnati Periods, Occurring in the Vicinity of Cincinnati, Ohio. Cincinnati, 1806. Gregory, J. W. On the Classification of the Palaeozoic Echinoderms of the Group Ophiuroidea. Proc. Zool. Soc. London, 64 :1035. Clarke, John M. The Lower Silurian Trilobites of Minne- sota. Geol. Minn. v. 3, pt 2, Paleontology. Prosser, C. S., & Cumings, E. R. Sections and Thickness of the Lower Silurian Formation in West Canada Creek and in the Mohawk Valley. N. Y. State Geol. Rep’t 15 (for 1895), p. 615. Prosser, C. S., & Rowe, R. B. Stratigraphic Geology of the Eastern Helderbergs. N. Y. State Geol. Rep’t 17 (for 1897), Pp. 320. Ruedemann, Rudolph. Note on the Discovery of a Sessile -Conularia. N. Y. State Geol. Rep’t 15 (for 1895), p. 690. Ruedemann, Rudolph. Evidence of Current Action in the Ordovician of New York. Amer. Geol. 19:367. Schuchert, Charles. Synopsis of American Fossil Brachi- opoda. Bull. U. S. Geol, Surv. 87. Ulrich, E. O. The Lower Silurian Lamellibranchiata of Minnesota; The Lower Silurian Ostracoda. Geol. Minn. we 4. pt 2. Ulrich, E. O., & Scofield, W. H. The Lower Silurian Gas- tropoda, Shictcr (40) 1898 Whitfield, R. P., &. Hovey, E. O. Catalogue of the Types and Figured Specimens in the Paleontological Collections of the Geological Department, American Museum of Natural History, Bul. Amer. Mus. Nat. Hist. 11:1. (41) 1899 White, T. G. Report on the Relations of the Ordovician and Eo-Silurian Rocks in Portions of Herkimer, Oneida and Lewis Counties. N. Y. State Mus. Rep’t 51 (for 1897), p. 21. 72 (42) (43) (44) (45) (46) (47) (48) (49) (50) (51) (52) (53) (54) (55) (56) (57) (58) 1900 1900 IQOI 1902 1903 1905 1906 1908 (59) (60) (61) (62) (63) 1909 NEW YORK STATE MUSEUM Se re — Prosser, C. S. Sections of the Formations along the Northern End of the Helderberg Plateau. N. Y. State Geol. pee? t 18 (for 1898), p. 5I. Jaekel, Otto. Stammiesgeschichte der Pélmiatocoes! vo Cumings, E. R. Lower Silurian System of Eastern Mont: gomery County, N. Y. .N. Y. State Mus. Bul. 34, p. 415. , Prosser, C. S. Notes on Stratigraphy of Mohawk Valley and Saratoga County. N. Y. State Mus. Bul. 34, p. 460. Bather, F. A. The Geologic Distribution of Pollicipes and Scalpellum, Sciences aiis! frie: Ruedemann, Rudolf. Hudson River Beds near Alteue and Their Taxonomic Equivalents. N. Y. State Mus. Bul. 42, Ruedemann, R. Trenton Conglomerate of Rysedorph Hill and Its, Fauna. N.Y. State Mus. Bul. 40;:p. Nickles, J. M. The Geology of Cincinnati. Jour. Cinc. Soc. of Natural History. 20:49. : ; Pocta, Phil. Ueber die Anfangskammer der Gattung Orthoceras Breyn. Sitzungsber. der K. bohm. Gesellsch, d. Wiss. : Ulrich, E. O., & Schuchert, Charles. Palaeozoic Seas and Barriers in Eastern North America. N. Y. State Mus, Bul. 52, p.-633.. ) Clarke, J. M. Classification of New York Series of Geologie | Formations. N. Y. State Mus. Handbook Ig. } Weller, Stuart. The Paleozoic Faunas of New Jersea | Geol. Surv. of New Jersey, Rep’t on Pal., v. 3. Cushing, H. P. Geology of the Northern Adiconall ! Region. N. Y. State Mus. Bul. 95. i Cushing, H. P. Geology of the Vicinity of Little Falls, | Herkimer County. N. Y. State Mus. Baling7. | Grabau, A. W. Geology and Paleontology of the er | | Valley. N. Y. State Mus. Bul. 92. Cumings, E. R. The Stratigraphy and Paleontology of th ! Ordovician Rocks of Indiana. 32d Annual Rep’t of the | Dep’t of Geology of Indiana. Tt Elles, G. L., & Wood, E. M. R. Monograph of British | Graptolites; ed. by C. Lapworth. Pt VI. Pal. Soc. for | 1907; pt VII, 1908. | Kiimmel, H. B. Paleozoic Sedimentary Rocks in Franklin Furnace Folio, N. J:; U. S. G. S., Folio S61: | Ruedemann, Rudolf. Graptolites of New York, pt 2. N. y. | State Mus. Mem. It. a Stose, George W. Meneoraburs-Chusberaaas Folio, Pa.; | U. SiG. 8. Folio. 170. i Bassler, Ray S. The Cement Resources of Virginia West af | the Blue Ridge. Virg. Geol. Surv. Bul. 2 | 2 | Foerste, Aug. F. Preliminary Notes on Cincinnatian a | Lexington Fossils. Bul. Denison Univ. 14:289. LOWER SILURIC SHALES OF THE MOHAWK VALLEY 73 Miller, W. J. Geology of the Remsen Quadrangle. N. Y. State Mus. Bul. 126. Grabau, A. W. Physical and Faunal Evolution of North America during Ordovicic, Siluric and Early Devonic Time. Jour. of Geol. 17:231. 66) 1910 Miller, W. J. Geology of the Port Leyden Quadrangle, . Eewis County, N. Y.. N. Y. State Mus. Bul. 135. Schuchert, C. Paleogeography of North America. Bul. Geol. Soc. Amer., v. 20. 68) 1o1t Ulrich, E. O. Revision of the Paleozoic Systems, pts 1-3. see. Soc. Amer. -Bul. v. 22, no. 3. PALEONTOLOGICAL NOTES Sphenophycus nom. prop. & gl yen le, = (25 WE antity of finely preserved algal remains. In part these are identical with Sphenothallus latifolius, described by Hall from the top beds of the formation at Schoharie, but the eater part represents one or more different species, and many e hibit important features not shown by the original material. We should not have undertaken to describe these if we had not had the authoritative advice and encouragement of Mr David White regard- ing them, but we should have much preferred if Mr White would himself have agreed to write a note on these Lower Siluric algae. _ Hall (title 3, p. 261) described the genus Sphenothallus as follows: “Plant consisting of a stem, with diverging wedge-form aves, or of detached leaves having this form. Leaves apparently eculent or thickened, and sometimes subcoriaceous.” He cites two species as belonging to it, viz, Sphenothallus angusti- folius and S. latifolius. The former has been found by us as a rather frequent fossil in the Utica shale of Dolgeville ‘and elsewhere and on reinvestigation (1897, N. Y. State Geol. ‘Rep't I5) was referred to as a “ sessile Conularia.” The stem of the type specimen was found to be a cephalopod shell, to which the “leaves” are attached by basal disks. While we no longer onsider this species as properly belonging to the genus Conularia itself, there is no doubt in our minds of its taxonomic position with the Conularidae. It therefore can not be retained in the same genus with the other species, S. latifolius, if the latter is an alga, and the question arises which of the two should retain the generic name Sphenothallus. S. angustifolius is the first species described under the diagnosis and moreover the latter is gen work in the Schenectady shales has brought to light a great | FAS NEW YORK STATE MUSEUM i clearly shaped principally after this species. If, therefo ¢ | fe geuilarias it should retain the deere name and a néw one be selected for the second species. We therefore propose here the t name Sphenophycus for the second species. Both Sphenothallus angustifolius and Spheng = | from a chitinous or cibitchialanions substance. Following a sugges-_ tion of Mr White, I tested the organic matter of Sphenophycus b fire and found that it burns with a fair degree of completeness, leaving an ash residue consisting of clay and silica and probably | resulting from silt infiltration into the canals of the organism. This| evidence suggests the vegetable nature of the carbonaceous tests. The most remarkable portions of these vegetable remains are | the club-shaped bodies reproduced on plate 2, figures I-13. These, were all obtained in one block that had fallen from the cliff over-| hanging the Mohawk river at Aqueduct. They consist of an ellipti- | cal or circular distal smooth body borne on an equally smooth pedicel. The distal body is in well-preserved specimens flatten at the apex and in some this part is infolded. The wrinkles and| partial sections prove that the distal bodies were originally more or) of animal objects, notably of chimaeroid, gastropod and cephalopod) egg-cases, all of which suggestions were disproved by the kind ae i vice of Messrs Bashford Dean, Gratacap and Pilsbry. Mr White appendages. A specimen was observed showing these bladders attached to a spirally arranged group of the thalli of a Sphenophycu It broke when lifted up; the portion saved is reproduced on platelf 2, figure 13. This specimen and the apparent absence of an | apertures of the bulbs or of any substance originally inclosed within} them, are strong arguments in favor of that view. Likewise, thelj extremity, as well as the fibrous charactér of the pedicel seen some examples, and the auxiliary bulblike inflations (see plate 2,| figure 11) in the pedicel, point to the vegetable origin of these) . | ; LOWER SILURIC SHALES OF THE MOHAWK VALLEY 7 fossils and their-character of flotation appendages. We are not sure yet to which of the two species here distinguished they belong, although the present evidence indicates that they are referable to m. latifolius. : _ Several specimens of S. latifolius appear at first glance lobate (see plate 1, figure 1). _ It has been pointed out to me by Mr White that this appearance is due to the presence of cuplike marginal cavities and that these are apparently connected with the neural system which is canalicular. These cups and the canals are well seen in plate 1, figure 2. Besides the genotype, S. latifolius, -which according to the original description possesses ‘“‘ broadly cuneate thalli” we have distinguished a second species, but there are probably more than two species present, as indicated by such thalli as those repro- duced in plate 1, figure 9. The cuneate thalliof S. latifolius were probably arranged spirally around a stem, as indicated by their wedgelike shape and by the specimen plate 1, figure 13. _ The largest thalli found are those typically represented by plate I, figure 5. While also possessing a broadly cuneate to trap- ezoidal outline, they are not single as thoseof S. latifolius, but, as again pointed out to us by Mr White, “ composed of rather slender, but rigid conical thalli, originating at the scarlike pits or depressions of the lower parts of the axis.” _ A third type is represented by plate 1, figure 9. Only one speci- men of this interesting form has been thus far obtained. It shows a pitted middle axis from which proceed lobate thalli, ornamented with broadly recurving lines. This material we consider too im- perfect for specific differentiation. ) Cyathodictya ? tubularis nov. t Certain layers of the Canajoharie beds at Canajoharie are covered with multitudes of small elongate bodies which contrast by heir brown coloring with the black shale. These bodies are mostly about 5 mm long and then regularly conical in outline, but reach as 1The original description is: “Leaves broadly cuneate, somewhat thickened at the outer margin, and truncate at the lower extremity; surface obscurely striated. The specimens are often marked on one side by a ridge or midrib along the center, and sometimes transversely wrin- Bui? These leaves all appear to have been thick and succulent, like the uci.” 76 NEW YORK STATE MUSEUM much as 15 mm in length and these larger specimens are cylindrical in outline. While completely flattened out, the roundish aperture at one end and the thickened lateral margins demonstrate that the bodies were originally tubular and rather thick-walled. The proximal end fades out in most specimens; in many others it is jagged as if broken off and in a few it contracts to a blunt point The long tubular specimens show no appreciable contraction at either end. Fig. 9 t Fig. 8 Fig. 8-12. Cyathodictya ? tubularneaiee Fig. 8. Group of specimens of usual size. Natural size. Fig. 9. Grou of large specimens. Natural size. Fig. 10. Specimen showing aperture, : Fig. 11. Specimen showing spicules, x 5. Fig. 12. Fairly perfect specime Type, x5: a shale at Canajoharie, N. Y. The substance of the fossil is preserved and this as well as | thick margins show the walls to have been quite substantial. We have referred this gregarious organism with doubt | Cyathodictya largely on account of the form and thick walls of th bodies. Owing to their small size we have not been able to satis! ourselves as to the presence of spicules although delicate lines gesting these are seen in some places on the walls, the longitudi LOWER SILURIC SHALES OF THE MOHAWK VALLEY 77 spicules being more distinct in some, the transverse in others. ‘Larger dictyonine spicules (typical hexactines), corresponding in size to those of the Utica species C. reticulata (Walcott) have been found in adjoining layers, demonstrating the actual pres- ence of dictyosponges in these beds. Fig. 14 Fig. 13-15. Dictyonema arbuscula (Ulrich) } Fig. 13. Small rhabdosome, x 5. Fig. 14, 15. Fragments of distal por- ' tions of larger rhabdosomes, x 5. . _ Indian Ladder beds, at the Indian Ladder, N. Y. Dictyonema arbuscula (Ulrich) Ph 2, fig. 16 _ Asmall Dictyonema was found to be not infrequent in the Indian ‘Ladder shale at the Indian Ladder, which proved to be identical with /€ species hitherto recorded only from the Eden (formerly Utica) Shale of the neighborhood of Cincinnati. According to Doctor re a A NEW YORK STATE MUSEUM noted in the Graptolites of New York, part 2 (title 60, p. 151). Like © other Dictyonemas this species also shows a tendency to undulating, i alternatingly adnascing branches in the proximal portion, giving that part a Desmograptuslike aspect, while it is a typical Dictyonema in the distal portions (see text fig. 13). Dictyonema multiramosum nov. Pl, 2, fig. 16 ich ES aI Description. Rhabdosome of small size (32 mm high) apparently | cyathiform, arising from a short thick stem. Branches extremely _ thin and closely arranged, about .5 mm apart and .2 mm wide, bifurcating at frequent inter- vals, slightly undulating; mostly of rather straight appearance, frequently coalescing where] . brought in contact by the wavy form of the branches, or where the latter are straight, with thin dissepiments in long intervals. Thecae not clearly seen. : Horizon and locality. Schenectady beds near Rotterdam Junction, N. Y. | Fig. 16. Remarks. But a single specimen of this — Dictyonema species was obtained and this being inclosed in multiramosum a sandy shale, is far from perfect in preserva- nov. tion. It is therefore possible that the species ; Portion of rhab- should be rather referred to Desmograptus — dosome, x 5. which it approaches in some portions of the © Schenectady beds, frond. Rotterdam Junction, We have not observed any species in either IN: -Y.. : Z the Trenton or Utica shales which approaches D. multiramosum in the extreme delicateness of the | rhabdosome. Dicranograptus nicholsoni Hopkinson var. parvulus nov. The Canajoharie shale at Morphy’s creek near Pattersonville, | N. Y., contains in its basal layers, within a few feet of the under- | lying Glens Falls limestone a diminutive form of Dicrano- | graptus nicholsoni which deserves recognition as a variety, as all the specimens of this bed retain unitormly their peculiar | character. The main differences from the typical (4-11 mm). The form of the thecae does not seem to differ from that of the larger types. The biserial portion has been seen in only one specimen and in this the axillary angle is smaller than in nicholsoni : ty pus, namely about 10°. ; The width of the stipe is not materially different from that of nicholsoni. _ The most remarkable feature of the spec- _ imen retaining the biserial portion is the con- _ tinuation of the axes of the biserial branches in antisicular direction. These axes have to our knowledge not been observed in either ‘ Dicellograptus or Dicranograptus outside of the theciferous portion. The free portions _ are too long and delicate to have been theci- . ferous and to have secondarily become sepa- rated from.the thecae. The rhabdosome of _Dicranograptus was hence suspended from two axes which, as the parallel and slightly ‘convergent final direction of the axes sug- gests, proceeded from a common initial point. _ The specimen exhibits also a large “ web ” between the branches. Meicellograptus nicholsoni possesses in the slate belt of New York a much larger vertical range than we had in- ferred in Memoir 11, page 318. We had cited it there from the “Trenton shales” (Normanskill shale) in several varieties and in typical development from the Utica of South Trenton, the Mohawk valley and the ‘Shales at Saratoga lake, which were also Supposed to be of Utica age. The shales “which carry D. nicholsoni in the Mo- ' hawk valley are in the present paper referred i LOWER SILURIC SHALES OF THE MOHAWK VALLEY 79 nicholsoni are the closer arrangement or smaller size of the thecae, which number 14 in 10 mm, and the greatly. varying length of the biserial. portion Bigs 17 — - aT IA Me a _ ~. qd I, ‘ oe en! IIO NEW YORK STATE MUSEUM Cyclonema montrealense Billings Pl. 7, fig. 7 The gritty sandstone bed of the Snake Hill formation at Snake hill has afforded the impression of a small Cyclonema which has the characters of C. montrealense «from the Trenton lime- stone of the island of Montreal. It agrees especially with that species in having the whorls “ moderately ventricose, most promi- nent in the lower half,’ a rather deep suture, in the character of the spiral lines, of which there are about ten in 4 mm with one or two smaller ones between each pair of the larger lines. The spire is somewhat higher than Billings’s description (title 4, page 30) and figure require, but since Ulrich (title 39, page 1059) after an ex- haustive study of the western Cyclonemas states that the relative height of the spire is a very unreliable character, and that the form of the whorls is a better character, but that the surface markings have served him best of all in separating the various species, we do ~ not feel warranted in attaching much importance to this difference id in the spires. ! Cyclonema cushingi nov. Pl 7, tie. 810 We had repeatedly observed fragments of a gigantic Cyclonema in the Shake Hill beds at Snake hill, but owe the fairly perfect speci- | men here figured to the collecting spirit of Prof. H. P. Cushing to | whom we gladly dedicate this species in recognition of the fact that | he does not disdain to be interested in fossils. The specimens at hand are too badly crushed to allow a descrip- | tion of the species, but since the form is obviously closely allied to | C. hageri Billings (1865, page 29), a Trenton form from Mon | ee ee EE ee, by determining its differences from the Canadian relative. Snake Hill type has in common with the latter the large size a appears to agree, the upper ones being rather flat or somewhat de pressed in the middle, while it is not certain, whether the last volu- | tion was as ventricose as in C. hageri, or became concave in | account of the presence of the oblique folds and a protruding lowe rim in the specimen which indicate a former greater expansion Of that volution. The apical angle is apparently less than in the othe LOWER SILURIC SHALES OF THE MOHAWK VALLEY 1 @ _ species, but the evidence in regard to this character is not conclusive. The surface sculpture exhibits revolving lines which are markedly closer arranged than those of C. hageri, where they are from one to two millimeters apart, while here the larger ones are one millimeter apart, but contain a smaller one between them. C. hageri possesses “strong angular ribs or undulations of growth from half a line (1 mm) to two lines (about 4 mm) apart becoming _ more prominent with age. The Snake Hill form has on the older _ volutions closely arranged subequal growth lines, which on the last volution become gathered into elevated bundles of lines, the _ middlemost of which are thicker and broader than the others. The high folds on the type specimen are largely due to the lateral com- pression of the shell. It will be noticed that our species stands in its characters between 'C. montrealense and C. hageri. The form from the _ Jacksonburg limestone of New Jersey referred by Weller (title 53, page 186) to C. montrealense, has also its revolving lines farther apart than the Canadian type of that species and more - convex volutions, and may represent a fourth expression of the same group. Its revolving lines are of the character of those of C. cushingi. ———" 06 ae Hyolithes pinniformis nov. 6 er gee adage oe | Shell small, slightly bent in proximal portion, expanding some- _ what rapidly, one side flattened or slightly convex, the other with a _ blunt median keel. The flat side is longer, projecting with an evenly rounded lobe beyond the aperture, while the keeled side forms a blunt reéntrant angle. The surface is furnished with closely ar- ranged sharp arching transverse striae (growth lines, which are most distinct on the flat side; and with fainter longitudinal lines. -Operculum not observed. _ Horizon and locality. Canajoharie shale at Canajoharie, N. Y. Remarks. This species belongs to the group of Hyolithes s. str. ‘in distinction from the subgenus Orthotheca, Novak, according to the character of its aperture. It is distinguished from the other Trenton species of Hyolithes, save H. baconi Whitfield, by its more robust form. The latter species, from the Trenton of Wis- ‘consin is considerably larger and the apertural lobe of the flat side is less projecting. -_ ae The type specimen (plate 7, figure 12) measures 13.5 mm in length and 4 mm in width. It shows a distinct, very concave septum _ in the apical portion. Our specimens are so flattened that their — section can not be conclusively determined. It seems to have been elliptical with one side angular. | II2 - NEW YORK STATE MUSEUM | | 4 i Orthoceras arcuolineatum nov. Pi. Sa fies 12 Re mB | et in ta Slender, small orthoceracone, increasing at the rate of .5 mm of diameter in length of 10 mm. Section elliptic, nearly circular, the minor and major diameters as 7.1 to 7.5 mm. Camerae shallow, nearly four times as wide as deep. Septa closely arranged, about 2 mm apart. where the diameter of the conch is 7 mm deep, their) depth approximately corresponding to that of the camerae. Sutures ~ arching slightly up on one side. Living chamber not known. — Siphuncle centren, small, about one-seventh the diameter of the conch; segments cylindrical, the funnels short and straight. Orna- mentation consisting of relatively widely separated (about 2 in I mm) sharp raised transverse lines, or ridges, which are inter- sected by extremely fine longitudinal lines. The transverse lines are strongly bent upward on one of the narrow sides of the conch. Horizon and locality. Canajoharie shale at Ford Edward, N. Y. 7 — Remarks. This species is based on only the small fragment that — is figured here. This shows, however, especially in the ornamenta- © tion, characters that distinguish it from other Trenton species known ~ to us. It is apparently, from the character of the siphuncle, a true Orthoceras. Pha Sh Fe Sw Orthoceras hudsonicum nov. Pl..8, fis--2=10 Small to medium sized, slender, slightly curved cone, with closely arranged septa and subcentral, narrow siphuncle. The cone widens so gradually that in a distance of 50 mm it expands from 5 mm to 10mm or less (measured in compressed specimen). The septa equal in depth the chambers; they are closely arranged, about 2 mm apart, where the conch is 7 mm wide; the sutures are straight transverse. The siphuncle is centren, wide, about one-third the width of the conch, the funnels apparently short and straight. The living cham- ber and aperture have not been observed. The nepionic conch possesses only fine longitudinal striae, of somewhat irregular char- LOWER SILURIC SHALES OF THE MOHAWK VALLEY 1a3 _ acter, and the mature conch transverse sharp striae, about four to _ the millimeter; the neanic conch exhibits an intersecting system of both, visible to the naked eye, while on the mature conch still shadowlike traces of the longitudinal lines are visible under the lens. Formation and locality. In the Canajoharie shale at Alplaus creek, Saratoga county, N. Y., and other places. Remarks. This species is easily recognized by three characters ; its slender, slightly curved shell, the closely arranged septa and the delicate surface sculpture. _ The specimens are all more or less crushed, and the septa mostly _ dissolved and the conch filled with shale. We have, therefore, been unable to satisfy ourselves completely as to the generic determina~ tion of the species, and we do not know whether it is a true Orthoceras or not. On account of the relative width of the siphuncle _ it approaches Baltoceras. _ The surface sculpture corresponds exactly to that of Endo- ere proteiforme var. tenuitextum, var. -tenuistriatum and lineolatum Hall, as described in Palaeontology of New York, volume 1. These Trenton forms do not belong to Endoceras proteiforme but are orthocera- tites that need revision. Also the common and often cited “ Endo- metas proteiforme” of the Utica slate (title 3, plate 85, figure 1) belongs in the same group which eventually will be referred to, we Meneve, as Orthoceras tenuitextum Hall. They all have the same rate of growth, the same closely set septa and the _ same characteristic surface sculpture. We would also have referred 'the species here described to Hall’s species if it were not for the curvature of the conch. _ A species identical with our type save its coarse cancellated ‘sculpture, has been described by Walcott (title 9, page 22) as O. oneidense from the Utica shale of Trenton, N. Y. The most interesting feature of the material from the Alplaus creek is the presence of the embryo shells or protoconchs on the partly pyritized and partly calcified nepionic portions of the conchs - (see plate 8, figures 4, 5). = Lhe history of the investigation of the protoconch of the ortho- "ceratites is a very interesting one. Branca considered as the embryonal shell or protoconch the cup-shaped termination of the ‘conch as usually found. Hyatt viewed this chamber as the first “chamber and the cicatrix which it generally bears upon its distal “surface as the remnant of the protoconch. The latter was figured by II4 NEW YORK STATE MUSEUM : him in the Genesis of the Arietidae as a very small, shrunken wart- like appendix, the aspect of which was explained by assuming it to have been composed of conchiolin, which also accounts for its almost _ invariable absence. In 1893 Clarke (title 20, page 112) announced the discovery of a small fragment of an Orthoceras conch from the Devonic of New York that retains a good-sized calcified protoconch. | This minute and interesting specimen was found in the same geolo- gical horizon (Styliola-limestone) with protoconchs of Bactrites and distinguished from them by the central position of the siphuncle. The very similar protoconchs and early stages of Bactrites were first described by Clarke in a subsequent paper (title 23, page 37) and more fully in the first part of the Memoir on the Naples Fauna (page 122). Hyatt in his Phylogeny of an Acquired Characteristic assumes regarding the protoconch of that Orthoceras the stand that this “form certainly has the characters of an Orthoceras, but the protoconch is large and like that of the Ammonoidea. The shell may be transitional from Orthoceras to Bactrites, but it is probably not a typical form of Orthoceras.” This view which gives the small _ fragment from the Styliola limestone still greater phylogenetic in- terest, was later (op. cit., page 130) concurred in by Clarke, who” considers it “ conceivable that such differences as are here indicated by the young [of Orthoceras and Bactrites] may. be totally extin-. guished in the later growth stages so that the mature form of the species in question may be before us, though present knowledge does not enable us to recognize it.” Even if the unique small shell” described by Clarke represents but a transitional form, it demon- strates that there must exist true Orthoceras with like large “al | careous initial chambers. Indeed such were found not long after by Pocta. In 1902 Pocta (title 50) published a note on the initial chamber of Orthoceras, his observations being based on the sections of diabas tuffa of the band e,, of the Bohemian Upper Siluric. These section showed clearly the presence of a baglike protoconch in both longi- conic and breviconic orthoceratites, the species of which, however could not be determined. Pocta obtained the following conclusions: 1 The genus Orthoceras possessed a calcareous initial chamber. 2 The form of the same was baglike, somewhat contracted down- ward, but always of greater width than the first air chamber. 3 This protoconch exists only in juvenile stages, later it i absent, and its traces in mature individuals are extremely ra (Clafke). ; i LOWER SILURIC SHALES OF THE MOHAWK VALLEY I15 _ 4 The first siphonal funnel was collarlike reflexed and thus formed the scar (Barrande’s “ cicatrix’’). This first siphonal funnel has as a rule a different shape from that of the other funnels of ‘the conch. | _ Our material consisted only of about half a dozen protoconchs which, however, were large enough (1.6 mm wide) to be broken out and in two instances made into thin sections. Both the exterior view and the sections verify Pocta’s observations as to the width of the protoconch being greater than the first camera and the reflexed character of the first funnel. It will be noticed that in O. hud- sonicum the volume of the protoconch corresponds ARPES | mately to that of the first camera. _ This is the first observation of the protoconch of an Orthoceras in the Lower Siluric, Doctor Clarke’s specimen coming from the Devonic and Professor Pocta’s from the Upper Siluric. The _ different character of the nepionic conch of Endoceras has already _ been described by Holm in 1885 (Pal. Abh. von Dames and Kayser, volume 3, and Geol. Foren. i Stockholm Forhandl. 1896, volume 18). The protoconchs of orthoceratites are by no means rare in the Utica shale, for we had already obtained a large series of pyritized speci- ~ meng at Dolgeville some fifteen years ago. These, however, were lost in transportation and the bed has become inaccessible by the _ building of adam. The Dolgeville material was the same or a very closely related species. Oncoceras (?) sp. Pl, 8, fig.012 A completely flattened specimen from the Canajoharie shale at North Albany. Its condition does not allow either a definite generic _ determination or a sufficient specific diagnosis. The living chamber ‘was short and the apertural portion somewhat contracted; the aperture apparently regular and circular. The septa are seen only faintly, they were closely arranged and arched on both the ventral and dorsal sides. The siphuncle is very indistinct, apparently with straight segments. The form seems to be distinct from the other “Trenton species of Oncoceras but would not warrant being named. Conularia trentonensis var. multicosta nov. Both the Schenectady and the Snake Hill beds have furnished ‘specimens of a Conularia which possesses the characteristic apical “angle (18°-20°) and sculpture of C. trentonensis,iea “system of transverse ridges crossed by closely set longitudinal bars, TiO: NEW YORK STATE MUSEUM : with the difference, however, that the sculpture is much finer in the shale variety, the ridges and bars being just about twice as closely — _ set and correspondingly lower than in the trentonensis (15 to 17 ridges in 5 mm as against 6 tog in C. trentonensis)s This difference having been found to be constant in all specimens observed in the shale (Snake Hill beds at Watervliet and the Schenectady beds at Schenectady and Schoharie Junction), it becomes necessary to recognize it as of at least varietal importance. © We therefore propose to distinguish this form as var. muIti- C/OrSal ik It represents the other extreme of variation to the ine described by Emmons (Amer. Geology, 1:208) as C. hudsonia from the Lorraine beds at Lorraine, N. Y., which latter form exhibits the trentonensis-sculpture about twice as coarse as the Trenton type. __ A fragment of a specimen from Watervliet retains part of the apertural lobe. The sculpture on this consists of the transverse ridges which are much more crowded than on the lateral faces of © the shell and sharply bent forward in the middle. Eoharpes ottawensis (Billings) PT. Oa ie or A single specimen found in a loose slab of Snake Hill shale on © Snake hill, represents thus far this Canadian species in our State. The species was first described from the Trenton limestone of Ottawa (Can. Pal. Fossils, 1865, 1:182) ; later a doublure of a head shield from the Galena of Wykoff, Minnesota, was also referred with doubt to this species by Doctor Clarke (title 32, page 77). Weller (title 53, page 191) has also recognized the species in the fauna from the Jacksonburg limestone at Jacksonburg, N. J., and Bassler (title 62, page 111) lists it from the Liberty Hall limestone (Chazy) of Virginia. Our specimen has been slightly laterally compressed and there- fore appears somewhat more slender than the type, but otherwise it fully agrees with the original drawing of the latter. It also dis- tinctly exhibits the surface punctae characteristic of Billings’s species. Isotelus gigas DeKay Bi ape. We figure here a fairly well-preserved specimen of this widely known trilobite which, labeled as coming from the bluestone quarries at Rexford Flats, N. Y., has been in the State Museum LOWER SILURIC SHALES OF THE MOHAWK VALLEY I17 for some time. It is the only example of this species known to us from the Schenectady beds and appears to agree in all essential characters with the Trenton ‘type. The fact that it is narrower and higher is due to lateral compression. ‘Proétus undulostriatus (Hall) Pl. 9, fig. 2, 3 Olenus undulostriatus Hall. Pal. N. VY. 1847; 12258, pl..67. ae. 3a, b. e Ct. Proétus parfviusctilus Hall. 13th An. Rept N: VY. State Mus. Nat. Hist., 1860, p. 120. Elliptocephala undulostriata S. A. Miller. North Amer. eol. & Pal., 1880, p. 546. Bathyurus sp. Whitfield & Hovey. Bul. Amer. Mus. Nat. Hist., me. 1, 1608, 11:70, 71. 'Proétus parviusculus Ruedemann. N. Y. State Mus. Bul. 42, 901, p. 536. Cyphaspis hudsonica Ruedemann. N. Y. State Mus. Bul. 4g, 1901, p. 64, pl. 4, figs. 8, 0. _ The writer described in 1901 several small cranidia from the black limestone pebbles from the Rysedorph Hill conglomerate which are especially characterized by a fine system of transverse or concentric sculpture lines, as Cyphaspis matutina, and another cranidium of broader habit from the supposed Upper Utica Shale of Green island as C. hudsonica. Collecting in the Snake Hill beds at Snake hill furnished a few years ago a cranidium plate 9, figure 3) which not only exhibits the identical charac- “teristic sculpture of C. matutina but also resembles it in all other features with the exception that it is a little broader and the frontal limb distinctly narrower. In the latter features it fully agrees with the C. hudsonica which comes from beds which we now know to be identical with the Snake Hill beds. This latter Specimen proves on reinvestigation to be exfoliated, for which eason the surface sculpture is not observable while the glabellar furrows are more distinct. - Hall had in 1847 described and figured as Olenus undu 0 - triatus from the “ Hudson River group” of Snake hill, the nold of a carapace and part of the thorax of a trilobite which since that author had referred in his early work a considerable number Xf Lower Cambric fossils to the “ Hudson River group,” had also een placed by catalogers in the Cambric, or rather since the original lescription is very brief and the figure quite unsatisfactory, it has Leos _ NEW YORK STATE MUSEUM ——_ been left out of consideration in discussions of the Lower Siluric faunas. Hall’s type, which was kindly loaned to us by Dr E. O.— - Hovey, proved, from gutta-percha squeezes, to be specifically iden- tical with the specimens in our collection from Snake hill and also with the other specimen formerly described by usas Cyphaspis hudsonica. We have here (plate 9; figure 2) introduces -a new figure of the original of Olenus undulostriatus from a gutta-percha squeeze. While Hall referred his species to Olenus and Miller placed the - same under Elliptocephala, Whitfield and Hovey in the catalog of © palaeontologic types of the American Museum of Natural History, have cited that type as Bathyurus sp. | | We had placed the cranidia from the Rysedorph Hill conglomerate ~ and of Green island with Cyphaspis on account of the form of the glabella and the large basal lobe. From inspection of the whole carapace and the thorax we have however become convinced that those species should be more properly referred to Proétus, the isolation of the basal lobe being too indistinct for Cyphaspis and the carapace relatively too broad and the glabella not prominent enough. On the other hand, while we recognize the similarity of the carapace of P. undulostriatus to that of Bathyurus in its former generalized conception, we doubt that this genus, as- characterized by its genotype, B. extans (Hall), could be made to receive forms like the present with a distinct thick anterionm margin and a much broadened base of the glabella through a more _ or less prominent basal lobe. All these are features characteristic | of Proétus and are becoming still more emphasized in Cyphaspis,_ | but absent in Bathyurus. - Proétus matutinus Ruedemann from the Rysedorph Hill) | conglomerate is obviously a closely related: older form, the black pebbles being probably of Black River and the Snake Hill beds of Trenton age. It is mainly distinguished by the broader frontal limb ~ of the cranidium. The glabella is also distinctly more convex, but — this may be due to the preservation in limestone, the shale fossils always being more or less flattened. The fine anastomosing sculp- ture lines are identical in P. undulostriatus and mat wd ti mais. | ; | In New York State Museum Bulletin 42, 1901, page 536, the | present writer has cited from the “ Middle Trenton shales,” exposed — at the Brothers quarry at South Troy, Proétus parvius- culus Hall, from a cranidium collected by him at that locality. gg? Sn sag ba Saeed pee ty Seale a ten e LOWER SILURIC SHALES OF THE MOHAWK VALLEY IIg The same is now packed away and at present not accessible, but the writer feels sure that this cranidium also belongs to P.undulo- striatus from his recollection of the minute fossil and from the fact that P. parviusculus is clearly a very close relative of P. undulostriatus. The small specimen from Troy was exfoliated and therefore failed to show the striae. ' %P.parviusculus in size and outline of carapace and glabella : would appear to be difficult of differentiation from the Snake Hill species. The fact that its surface is described as “ smooth, or very _ finely granulose’’ would seem to furnish a distinctive character. _ Beecher (1895, p. 174) states, however, regarding the surface sculpture of this species: “In the original description of this species, no mention was made of fine undulating striae ornamenting the entire dorsal surface of the test, nor of the basal lobes of the glabella. Both these features are present in the type specimen, which _ is from Cincinnati, Ohio, as well as in all the specimens from the Utica slate near Rome, New York.” _ If it were not for the fact that the cheeks and glabella of the eee ofr PF. undulostriatus and P. hudsonicus _ are relatively broader than those figured of P. parviusculus and the genal spines diverging instead of being subparallel, we should _ not hesitate to consider parviusculwus a synonym of the older term. Since these differential characters in the scant material at our disposal — and especially in the type specimen — may be due _ to longitudinal compression, it is possible that later collections will demonstrate the identity of the Cincinnati and Snake Hill forms. At any rate, if different, they are very closely related. _ The species here described presents in its outline great similarity 'to Proétus latimarginatus Weller from the Jackson- burg limestone of New Jersey. The latter type is however described as possessing a finely granulose surface. Acidaspis crossota (Locke) Pl. 9, figs. 4, 5 A small Acidaspis from the Indian Ladder beds, represented by a _ cranidium and several fine cheeks, has been identified by Doctor Ulrich with Acidaspis crossota Locke, a form hitherto known only from the Cincinnati group of the neighborhood of Cincinnati. It is recorded by Nickles as ranging through the Eden _ (“ Utica”) shale of Cincinnati. I20 NEW YORK STATE MUSEUM Calymmene senaria Conrad Pl. 9, fig. 6-10 The Canajoharie shale in the Mohawk valley often contains as one | of its more frequent fossils quite large specimens of Calym =| mene senaria. These, as first noticed by Doctor Ulrich, bear | upon the occipital. ring a larger median tubercle not found in the common Trenton or Utica specimens and obviously representing a varietal character. It is distinctly seen on the specimen reproduced | || in figure 6, but the largest specimen here figured also possessed ag : larger, though flatter elevation upon the middle of the occipital ring. | The material of this species from the Canajoharie shale proved | especially interesting through the fact that the fine black shale hag retained the earlier growth stages. Among the latter was founda | well-preserved specimen of a protaspis (see plate 9, figure 7),)) which to our knowledge has not as yet been observed of this genus. ‘The very prominent marginal eyes and the fine segments of the glabella, the middlemost of which is largest, are the most striking | features of this trilobite embryo. We also figure a nepionic and | early neanic stage to illustrate the changes in the glabella, leading — to the suppression of the embryonic annulations. The protaspis” here figured is practically identical with that referredto Proétus parviusculus by Beecher, and the question arises™ whether it should not also be referred to that genus. Since our — protaspis is fairly well connected with the adult Calymmene by ~ the neanic stages here figured, and Proétus parviusculus has not been found associated with it in the Canajoharie beds; we feel certain of its ontogenetic connection with the common Calymmene senaria of that formation Ulrichia ? bivertex Ulrich PL og, fige sins 1 Associated with Primitiella unicornis the Came joharie shale at Canajoharie contains in considerable numbers an ostracod of rather striking appearance through two prominent tuber- cles near the dorsal margin. This species was first published by Doctor Ulrichas Leperditia bivertex (title 8, page 10) from the neighborhood of Cincinnati and is now referred by him to 1 The larval stages of Trilobites. Amer. Geologist 16, pl. 9, figs: 5, 6. LOWER SILURIC SHALES OF THE MOHAWK VALLEY {2i the genus Ulrichia with some doubt. It is usually as at Canajoharie associated with Primitiella unicornis in the lower Tren- ton and in the “ Utica ” of Cincinnati. Eurychilina subradiata Ulrich Pl. 9, fig. 16 | _ A specimen of this species which has been recorded by Doctor Ulrich (Jour. Cin. Soc. Nat. Hist., 1890, 13:126; Geology of Minnesota, part 2, 1897, 3:661) from “ Birdseye and Lower Trenton” of the Middle West (Minnesota-Tennessee) was also collected in the shaly basal Trenton of the Canajoharie section. The New York type is according to Doctor Ulrich a close derivative of the western form which is there a good Black River species. Primitiella unicornis Ulrich var. Pl 9,.fig. 13) 14 This minute ostracod was first made known by Doctor Ulrich in 1879 (title 8, page 10, plate 7, figure 4), and later more fully described and illustrated in the Geology of Minnesota (title 38, page 649). It is stated by its author to occur abundantly in the lower part of the Cincinnati group about Cincinnati and also recorded _ by the same authority from near the base of the “ Hudson River group ” in Minnesota and in a slightly different variety from Mani- toba (title 15, page 50). Professor Nickles (title 49, page 71) _ records it from his lowest division of the “ Utica” at Cincinnati. Doctor Ulrich has denoted the Canajoharie form as corresponding to the “ basal Trenton variety.” This variety appears to us to be distinct from the type of the species in being more elongate and _ thicker in the posterior part. The spine is somewhat larger and _ the slight node in the dorsal depression larger. It has been observed by us in this State only in the lower part of the Canajoharie shale. eee ee ee Ceratopsis chambersi (Miller) var. 1. 0, fg.. 55 The Indian Ladder beds at the Indian Ladder have furnished us an ostracod which like many of its associated forms has before been only known from the Cincinnati region, whence it was first described eee ee veer ae I22 NEW YORK STATE MUSEUM inal — by S. A. Miller (Cincinnati Quar. Jour. Sci., 1874, 1:234) ana from the West. It has been more fully made known by Doctor Ulrich (Jour. Cinc. Soc. Nat. Hist., 1890, 137112) (Geaiies a Minnesota, part 2, 1897, 3 :676). } This species which in several varieties occurs in the Trenton, Cincinnati and Richmond formations, is characterized by the spine- like form of the postdorsal process. Our specimen represents a variety that may be peculiar of the Indian Ladder beds. One of its features is the separate development of the upper end of the post-— medium ridge as a small rounded node. Doctor Ulrich (op. cit. page 676) figures a similar specimen and remarks that it is the only case of the kind seen and may be abnormal. Pollicipes siluricus Ruedemann In New York State Museum Bulletin 42 (1901, page 518) the © writer described as Pollicipes siluricus a crustacean from the Snake Hill beds of Green island, N. Y., announcing it as the first lepadid or “ goose barnacle” yet known from the Paleozoic. — He has since learned that Dr W. S. Aurivillius had before (Bihang © Svenska Vet.-Akad. Handl., 28, Afd. 4, No. 3, 1892) made known ~ two species of Pollicipes and seven of Scalpellum from the Upper Siluric of Sweden, thus leaving to the Snake Hill barnacles only the distinction of being the first Lower Siluric or Ordovicic ones known. — In a note on the geologic distribution of Pollicipes and Scalpellum — by Doctor Bather (title 46, page 112) this author suggests that — my figures of Pollicipes siluricus belong to more thamm one species and that therefore a holotype of P. siluricae should be selected and the species separated. Although Aurivillius’s species are based on differences in form of plates etc. of no greater amount than those in our material, we do not deem it safe at present 4 .to distinguish more than one species for the reason that the plates — have suffered distortion in the much contorted shales, and we there- | | fore restrict ourselves here to designating the original of figure 17, plate 2, op. cit. as the holotype. | Technophorus cancellatus Ruedemann Plone ai. 1S This peculiar fossil has been described by the writer (title 47, page 572) from the shale of Green island, Albany county, N. Y., then referred to the Utica, where it occurs in the same association as LOWER SILURIC SHALES OF THE MOHAWK VALLEY 123 found on Snake hill. We figure here two specimens showing addi- tional features. Our species is a very close ally of T. puncto- striatus Ulrich (title 22, page 685) from the Cincinnati group, with which it has above all the striking surface ornamentation in common. Doctor Ulrich writes me that T. cancellatus has a proportionally greater length and more prominent rostrum. Since T. punctostriatus occurs in the middle beds of the Cincin- nati group it is also considerably younger than the Snake Hill “species. _ Miller considered his genus Technophorus as belonging to the lamellibranchs and Ulrich (title 38, page 612) retained the genus in that class, pointing out, however, that in the surface ornamentation and the character of the beaks as they appear in casts of the interior, ‘the genus differs from all known Paleozoic representatives of the Bias, with the possible exception of Ischyrina Billings. The markings are such as to suggest the crustacean nature of ‘Technophorus and the beaks form a single pyramidal prominence instead of two separate points as in lamellibranchs. The Snake Hill species seems to be distinguished from the others by an especially ‘prominent beak (plate 9, figure 18). _ Doctor Clarke in describing a very similar fossil from the Oneonta sandstone (New York State sosenue Memoir 6, part 2, 1904, page 406) has stated that he is “more inclined to regard these Clavicle-bearing genera (Technophorus and Ischyrina) as bodies like Ribeiria and Ribeirella which Schubert and Waagen have shown to De apodiform crustaceans (Jahrb. der k. k. geol. Reichsanst. 1903, 53:337), adding that “it is doubtless true that Technophorus is a Tibeirioid crustacean.” Doctor Ulrich now also considers these genera as crustaceans. EXPLANATION OF PLATES © a ge Plate 1 125 Fig, 1 Fig. 2 Hie) 93 Fig. Fig. Horizon and locality. Schenectady beds. Aqueduct near Schenectady, N. Y. All figures are natural size. The originals are in the State Museum. SpaeEopnycus latifonus (Hall) Page 73 Example resembling Hall’s type. Lobate thallus, showing short conical riateeea es A large fragment of thallus, showing at the right lower margin th cavities, giving it a lobate appearance. | A thallus showing very distinctly the conical marginal cavities. Large thallus with radiating impressions and cavities. Small thallus showing perfect margin with cavities. Thallus with complete outline. Thallus with broad, partly overlapping lobes. _ ; Thallus showing papailelt distally diverging lines and a medial row of double pits, doubtfully referred here. \ Thallus with extremely lobate outline. The specimens, figures 4 8-10, only doubtfully referable to this species. 126 LOWER SILURIC FOSSILS 162 _N. Y. State Museum. Bull. ee _G. S. Barkentin del. Plate 2 Sphenophycus latifolius (Hall) Page 73 1-4 Specimens showing the more common aspects of the fossil 5 6 Natural size. Figure 1 shows also a bandlike breaking up of the test; figure 2, the most frequent and typical aspect of the bodies; figure 3, showing a breaking of the stem into longi- tudinal shreds at D; figure 4, specimen with long, thin pedicel. Specimen in which the upper test has become exfoliated, revealing a flattened interior space. Specimen in which the wrinkling suggests the originally inflated condition of the bulb; it also shows a bandlike shred of the pedicel. 7,8 Specimens remarkable for the extreme inflation of the bulb. 9 ig. IO if. LI ig. 12 ig. 13 T5 ig. 16 Figure 8 shows at 0 a cylindrical section of the pedicel. Specimen showing a marginal, distal wrinkle and slight extension resulting from the flattened apex of the bulb, folded upon itself. Specimen also distinctly showing the apical wrinkle or fold, and a slight inflation in the pedicel. Finely preserved specimen showing the flattened oval space at the top of the bulb and a bulbous swelling of the pedicel (at a). Specimen showing finely the apical flattening of the bulb with a central, probably accidental perforation. Fraement of fronds of Sphenophycus latifolius, showing their spiral arrangement and the stems of several speci- mens of bulbs. Circular, originally probably spherical body found associated with the bulbs. Figure 9-12 are x 2; the others natural size. Horizon and locality. Schenectady beds. Aqueduct near Schenec- tady, N. Y. Dictyonema arbuscula (Ulrich) Page 77 Specimen in natural size. Horizon and locality. Indian Ladder beds. Indian Ladder, Albany - county, N. Y. Dictyonema multiramosum nov. Page 78 Holotype. Natural size. Horizon and locality. Schenectady beds. Rotterdam Junction, Schenectady county, N. Y. 127 Diplograptus peosta Hall Fig. 17 Specimen in natural size from Indian Ladder beds. Indian Tae Albany county, N. Y. Diplograptus (Mesograptus) mohawkensis nov. Page 80 Fig. 18 Typical (holotype) specimen from Ganges ate Swartzt creek near Amsterdam, N. Y. Natural size. Fig. 19 Specimen (paratype) from Canajoharie shale at = Carlsbad Spr near Saratoga Springs, N. Y. Diplograptus (Amplexograptus) macer nov. | Page 82 2 Fig 20, 21 Cotypes. Natural size. Uppermost Canajoharie shale at Mina- ville, Montgomery county, N. Y. a The originals are in the New York State Museum. 128 LOWER SILURIC FOSSILS. _N. Y. State Museum. Bull. 162 PLATE 2 ee —L— Tas aa a ee ee a eae — = a _. ee a Ti ey a ES = Se SSS SS SSS eet Fh tt ee Fig. Fig. Fig. _ Fig. Taeniaster schohariae nov. Page 88 Holotype. x 5. The middle arm exhibits the ventral view. Upper Schenectady beds near Schoharie Junction, ‘Schoharie count; INGEY Edrioaster saratogensis nov. Page 86 Holotype. x 5. Specimen showing the five anifulacnel rays, ve aperture, subambulacral plates (at a) and the inner thecal ple of the interambulacra. i Paratype. x 5. Specimen showing three or the oral plates, j tinctly the suture-lines of one interambulacrum and what i apparently an anal pyramid (at a). Paratype. x 5. A badly crushed specimen which however ¥ el exhibits the extremital part of an ambulacral ray at b; the subambulacral pavement of plates at a. Snake Hill beds at Snake hill, Saratoga county, N. Y. Heterocrinus ? gracilis Hall Page 86 A specimen £PGAh the original locality of the species. Naturale Snake Hill beds at Snake hill, Saratoga county, N. Y. Carabocrinus cf. radiatus Billings Page 86 A calyx plate. Natural size. Snake Hill beds at Snake hill, Saratoga count Nye All figures are taken from squeezes. The originals are in ‘he aa York State Museum. ‘ 130 LOWER SiturRic FOSssILs. -Y. State Museum. Bull. 162 PLATE 3 “Ss. Barkentin del. ¢ ; 2 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Lingula rectilateralis Emmons niteiaoadill tlie as om n= OLE in. A RI Tiny. Saas ea age Page oI I Specimen figured in natural size. Schenectady beds. Dettbarn quarry, Schenectady, N. Y. Orbiculoidea tenuistriata Ulrich ‘Page of 2 Pedicle valve. x 4. Top of Frankfort shale, one: gulf, Ns Xe Plectambonites sericeus (typus) Sowerby Page gI 3, 4 Two pedicle valves, showing the mesial fold. Figure 7x2; Figure 8 x 3. 5 Brachial valve. x 2. From squeeze. 6 Interior of brachial valve. x 2. From squeeze. Snake Hill beds. Snake hill, Saratoga county, N. Y. Plectambonites centricarinatus nov. i Page 92 7 Holotype. Pedicle valve. x 4. | Indian Ladder beds. Indian Ladder, Albany county, N. Y. Plectorthis sp. ci. whitfieldi (N. H. Winchell) Page 92 8 Brachial valve. Natu-al size. From squeeze. ; Snake Hill beds. Snake hill, Saratoga county, N. Y. Plaesiomys retrorsa (Salter) Page 93 9 Brachial valve. Natural size. From squeeze. 10 Cardinal portion of brachial valve. x 2. From squeeze, 11 Pedicle valve. Natural size. 12 Enlargement (x 5) of surface. Snake Hill beds. Snake hill, Saratoga county, N. Y. Plaesiomys cf. porcata McCoy Page 93 13. Pedicle valve. Natural size. From squeeze. Snake Hill beds.. Snake hill, Saratoga county, N. Y. Clitambonites americanus (Whitfield) Page 94 14,15 Two views of brachial valves. Natural size. 16-19 Views of the pedicle valve. Natural size. Snake Hill beds. Snake hill, Saratoga county, N. x All originals are in the New York State Museum. 132 LOWER SILURIC FOSSILS. 162 { N. Y. State Museum. Bull. PLATE 4 WW) WA 4 Barkentin del. Whiteavesia cincta nov. Page 95 Pee T. stiolotype:.” 3; | . Snake Hill beds. Snake hill, Saratoga county, N. Y. Whiteavesia cumingsi nov. Page 06 Fig. 2 Specimen that is probably but little digtoreed Holotype. <2 Fig. 3 Another specimen, showing a frequent expression of the for Paratypesaxceze 5, Snake Hill beds. Snake hill, Saratoga county, N.Y. Prolobella ? trentonensis (Conrad) Poe 97 His... A’ (Speemien,, 9 x (2, ; - Canajoharie shale. Canajoharie, Montgomery cont N. Orthodesma ? subcarinatum nov. Page 96 Fig. £6 7 Specimens (cotypes) showing the more frequent and appar n least distorted appearances of the species in the folded st “OL Stake Inilh. oc /1us. “4 Fig. § Dorsal view. x 1.5. Snake Hill beds. Snake hill, Saratoga county, N. Y. Whitella elongata nov. Page 98 Fig. 9 Holotype. Natural size. Fig. 10 Dorsal view of same. : Snake Hill beds. Snake hill, Saratoga county, N. Y. , Clidophorus ventricosus nov. Page 99 Fig. 11, 12 Lateral and anterior views of the holotype. x 3. A Fig. 13 A more elongate specimen showing hinge-denticles. x Lae Fig. 14 A specimen with very distinct clavicle. x 3. : a : Snake Hill beds. Snake hill, Saratoga county, N. Y. Clidophorus foerstei nov. Page 99 Fig. 15, 16 Lateral and vental views of the holotype. x 3. _ Snake Hill beds. Snake hill, Saratoga county, } All originals are in the New York State Museum. 134 LOWER SiILuric FossiLs. . Y. State Museum. Bull. 162 PLATE 5 Fig. Fig. Fig. Fig. . 2,3 Lateral and posterior view of holotype. 2727 . 4, 5 Lateral and posterior views. x 4. . 7, 8 Lateral and posterior views of holotype. x 3. tp “Speemen. sc 2. aa . 13, 14. Two specimens (cotypes) showing the common oy ‘ Ctenodonta levata (Hall) Page 100 1 Right valve. 32: | ee Snake Hill beds. Snake hill, Saratoga county, N. Y. . Ctenodonta declivis nov. ‘ 162 tee UE (ia . Y. State Museum. Barkentin del. i § H's SL b Hails) Oy a a ay on a Sse ae - + a a _INSTI = Sa i 3 ‘3 2 YS SMITHSONIAN AAs, yy Vj N INSTITUTION eels SMITHSONIAN aiuvug NVINOSHLINS S31 FINO EE salu INSTI ‘ i < — a ee INV EIN VIitigiv we (SV et INSTITUTION Saluvagl IBRARIES ie NVINOSHLINS SAIYVuaIT eA a DILALILSNI_ NVINOSHLIWS sf NVINOSHLIWS NOILNLILSNI NOILNLILSNI SMITHSONIAN SJINVUSIT LIBRARIES SMITHSONIAN INSTITUTION . INSTITUTION OILMLILSNI NVINOSHLINS S3INVYGIT LIBRARIES Zz w a < = os é 1 uf ty § E: BiG Ge i= 2 Gy i ee = | a IBRARIES SMITHSONIAN INSTITUTION © w) > w sa +0 = ' ai — 6 Bw 8 : - | OILNLILSNI_NVINOSHLINS S3Iuvugit oT om iy S Je ‘ wo e — ow a \\ = 50 = NQe > — SS \ 90 id : — w IBRARIES SMITHSONIAN INST é 2 a w : = < = : - wi = SIN 2 2 3 BW VEEN a oO —U7“AwSAAY 62 = = . \ > ; -_— BN. ES = A = DILALILSNI_ NVINOSHLINS S3IYVYaIT - 4 > or pag w sf ss 7 . < fend oot ner = INSTITUTION NOILNLILSNI ee Fee EN Pee es ow NSTITUTION NOILNLILSNI - Ss AXE Ww SMITHSONIAN SJIYVYdIT LIBRARIES SMITHSONIAN NOILALILSNI ie ow = per eo va Oo = en = kins pan | — bao w) = ITUTION NOILALILSNI SMITHSONIAN LIBRARIES SMITHSONIAN INSTITUTION NVINOSHLINS Saiuvuali_ LIBRARI ES BRARIES ee NVINOSHLIWS SMITHSONIAN > ~~ ee < saiuvua S3alu ~ NVINOSHLIWS NOILNLILSNI NVINOSHLINS S INSTITUTION SMITHSONIAN {7 LIBRARIES S: A N ee ee h S In eee NVINOSHLIWS _S° NVINOSHLIWS ILOLILSNI ee ee = A N ‘una |