\ SS \\ . SS SS WKY ~~ UA AA * : ? NENA NRA EER ee eee nt eee wor ; we mith ee * ing tice Zoe 9 asm oN - PA ay Zhe’ ve) hey 4 ae h Ps? Die is ~, New York State Education Department NEW YORK STATE MUSEUM | both ANNUAL REPORT 1906 VOLA2 APPENDIX 5 \, 208b45 ell aa TRANSMITTED TO THE LEGISLATURE JUNE 26, 1907 ALBANY NEW YORK STATE EDUCATION DEPARTMENT 1908 | STATE OF NEW YORK EDUCATION DEPARTMENT Regents of the University With years when terms expire 1913 WHITELAW Reip M.A. LL.D. D.C.L. Chancellor - New York 1917 St CrarrR McKetway M.A.LL.D.Vice Chancellor Brooklyn 1919 DanteL BeacH Ph.D. LL.D. - - - - - - - Watkins wif Puiny, Ti Sexton EL.B. ELD, 5) -° = -=5 Sbealnyed 1912 T. GuiLrorp SmitH M.A. C.E. LL.D. - -- - - Buffalo 1918 WiLttiAM NotrincHam M.A. Ph.D. LL.D. - - Syracuse 1910 CHARLES A. GARDINER Ph.D. L.H.D. LL.D. D.C.L. New York I9i5 ALBERT VANDER VEER M.D. M.A. Ph.D. LL.D. Albany © 1911 EpwarD LautersAcH M.A. LL.D. - - - - - New York 1909 EuGENE A. PuitBiIn LL.B. LL.D. - - - - --New York 1916 Lucian L. SHEDDEN LL.B. .- - - - - - - Plattsburg Commissioner of Education ANDREW S.DWeaper 41,3. ELD. Assistant Commissioners Howarp J. Rocers M.A. LL.D. First Assistant Epwarp J. Goopwin Lit.D. L.H.D. Second Assistant Avueustus S. Downine M.A. Pd.D. LL.D. Third Assztstant 4 Director of State Library Epwin H. ANDERSON M.A. Director of Science and State Museum Liigtea Joun M. Crarxe Ph.D. LL.D. Chiefs of Divisions Administration, HarLaN H. Horner B.A. Attendance, JAMES D. SULLIVAN Educational Extension, WILLIAM R. EastMaAn M.A. M.L.S. Examinations, CHARLES F. WHEELOCK B.S. LL.D. Inspections, FRANK H. Woop M.A. Law, THomas E. Finecan M.A. School Libraries, CHARLES E. Fitcu L.H.D. Statistics, H1rAM C. CASE Visual Instruction, DELANcEy M. ELuis STATE OF NEw YORK No. 68 IN ASSEMBLY JUNE 26, 1907 doth ANNUAL REPORT OF THE NEW YORK STATE MUSEUM To the Legtslature of the State of New York We have the honor to submit herewith, pursuant to law, as the 6oth Annual Report of the New York State Museum, the report of the Director, including the reports of the State Geologist and State Paleontologist, and the reports of the State Entomologist and the State Botanist, with appendixes. ST Crain McKEeLway Vice Chancellor of the University ? ANDREW S. DRAPER Commissioner of Education Appendix 5 Geology 12, 13, 14 Museum bulletins 107, 111, 115 12 Geological Papers 13 Drumlins of Central Western New York 14 Long Lake Quadrangle : Published monthly by the New York State Education Department BULLETIN 401 MAY 1907 New York State Museum Joun M. CiarxkeE, Director Bulletin 107 GEOLOGY 12 GEOLOGICAL PAPERS PAGE Postglacial Faults of Eastern New York. J.B..WoopworTH 5 Stratigraphic Relations of the Oneida Conglomerate. C. A. EU AREEN AG Dn ithe 00s Fas ON 29 Upper Siluric and Lower De- vonic Formations of the Skun- nemunk Mountain Region. C. Js a) aE OGG. (Ou) Byres Aenea eee 30 Minerals from Lyon Mountain, : PAGE some New Devonic Fossils. WOuTNE NT Gua oi 2 cs tae cad Mak: An Interesting Style of Sand- filled Vein. JoHN M. CLARKE. 293 The Eurypterus Shales of the Shawangunk Mountains in Eastern New York. Joun M. CEAR KB! ye5 ic 295 A Romaniatnis ose Tred Pedic from the Middle Devonic of Clinton county. HERBERT P. New York. Davip WHITE... 327 WF OG Koon Coe esi Sole oe v SRE 55 | Structural and Stratigraphic On Some Pelmatozoa from the © Features of the Basal Gneisses Chazy Limestone of New of the Highlands. CHARLES York. Grorce Henry Hup- IP A RISE We oa he geese ee 361 SCO. ee RT re a ea act oR Ee Om PERI Oa ca L Soo Stayt. Shes fae 379 ALBANY NEW YORK STATE EDUCATION DEPARTMENT 1907 M167m-Jl6-1500 Price 90 cents 1913 1917 1908 IQgI4 Igi2 1918 IgIo IQI5 IQIr 1909 1916 STATE OF NEW YORK EDUCATION DEPARTMENT Regents of the University With years when terms expire WuitTELaw Reip M.A. LL.D. Chancellor ir New York St Crain McKetway M.A. LL:D. Vice Chancellor Brooklyn Dantev. Beacu Ph.D. LL.D... 2 Pry T. Sexton LL.B. LL.Dy (25 28 eee ales T. Guitrorp Smita M.A. C.E. LL.D. . . Buffalo Witiiam NottincHaM M.A. Ph.D. LL.D. . . Syracuse CHARLES A. GARDINER Ph.D. L.H.D. LL.D. D.C.L. New York ALBERT VANDER VEER M.D. M.A. Ph.D. LL.D. Albany EDWARD LAUTERBACH M.A. LL:D. .- = 2 New York EuceENE A. Puitpin LL.B. LL.D. 3 er ae op ewe MOrks Lucian L SHEDDEN ELB-< |: 2 2 ieee eee Petr co cen Commissioner of Education ANDREW S. Draper LL.B. LL.D. Assistant Commissioners Howarp J. Rocers M.A. LL.D. Furst Assistant Epwarp J. Goopwin Lit.D. L.H.D. Second Asststant - Aucustus S. Downine M.A. Pd.D. LL.D. Third Assistant Secretary to the Commissioner HARLAN H. Horner B.A. Director of State Library Epwin H. ANDERSON M.A. Director of Science and State Museum Joun M. Crarxe Ph.D. LL.D. Chiefs of Divisions Accounts, WILLIAM Mason Attendance, JAMEs D. SuLLIVAN Educational Extension, WILLIAM R. Eastman M.A. B.L.S. Examinations, CHARLES F. WHEELOcK B.S. LL.D. Inspections, FRANK H. Woop M.A. Law, Tuomas E. FInecan M.A. School Libraries, Cuartes E. Fitcu L.H.D. Statistics, Hiram C. CaszE Visual Instruction, DELANcEy M. Ettis New York State Education Department Science Division, July 7, 1906 Hor 4: S. Draper LL.D: Commissioner of Education My DEAR sir: I beg to communicate herewith for publication as a bulletin of the State Museum, a series of geological papers by various members of the staff of this division. 7 Very respectfully yours JoHN M. CLARKE : Director Approved for publication, July 9, 1906 Hed na pest Commissioner of Education Se hee OL New York State Education Department New York State Museum JouHn M. Crarxe, Director Bulletin 107 GEOLOGY 12 GEOLOGICAL PAPERS ~POSTGLACIAL FAULTS OF EASTERN NEW YORK BY J. B. WOODWORTH Introduction While investigating the changes of level which have affected the Pleistocene river and lake deposits of the Hudson and Cham- plain valleys, the writer noted certain small dislocations of the bed rock which have taken place in the comparatively recent time since the glaciation of the surface. The importance of these fractures as indexes of a rock movement which appears to be associated in time at least with the tilting of the continent in the postglacial epoch led to the following study of the distribu- tion and character of the fractures. A reference to the literature of the State showed that Mather in the original geological survey of the first district noted the occurrence of postglacial faults on the east side of the Hudson valley. Having first referred to a class of faults much more 6 NEW YORK STATE MUSEUM frequently seen in the glacial gravels, he makes the following statement in regard to the faults here referred to: The other class is where the slate rocks on the east side of the Hudson valley had been ground down, smoothed, deeply grooved and scratched across their edges; and since the action that had produced these effects the masses of slate had been shifted a few inches in a vertical direction by a slight fault, so that the grooves and scratches on the lower part of the mass were continued quite up to that part that had been elevated; and on the upper mass, the same grooves that had been once con- tinuous, were prolonged i in their former direction, with the same breadth and depth. This shift of position, or slight fault, must have been subsequent to the period when the scratches were made, or the scratches could not have been continued close up to the vertical surface of the more elevated portion,- and without wearing the sharp edge of the slate on the upper portion of the shifted mass. This locality was where the Quaternary had covered it, but the example can not with certainty be referred to that part of the Quarternary period of which we are now speaking; for it may belong to the elevation that took place after the drift period, and preceding the elevation by which the Quaternary deposits were raised to their present level. The locality and example referred to above, was observed by myself in Copake or Ancram near the north end of Winchell’s mountain, and not far from the base of Mount Washington, on the road from Copake to Boston Corners.t. Professors Merrick and Cassels were present with me, and I called their attention to this, as an important fact for them to observe, in consequence > of the kind of evidence thus afforded of the relative periods of time during which the rocks were disturbed in position. Pro- fessor Merrick, a few days afterwards, in his explorations, dis- covered several more localities near each other, about half a mile west. of Long Pond in Clinton,? where the same facts were observed. JI quote his report to me. An interesting phenomenon may be seen in the rocks about 14 mile west of Long Pond in Clinton. The parts of the rock have changed their relative position since they were worn down by the diluvial action. In two different places, at but a short distance from each other, one part of the rock has been raised, or the other part settled from 2 to 3 inches, the strata being nearly vertical. Five or six similar dislocations, of from half an inch to I inch, occur in the immediate vicinity. Of the dislocation of the rocks since the effects of the diluvial action upon it, there can be no doubt, as the scratches or furrows upon the elevated and depressed parts precisely correspond, and are carried on the latter entirely up to the former, the elevated ridge of which is unmarked or broken (unbroken?). These dis- 1This is probably the locality described below on p. 16. J. B. W. 2] have not yet seen this locality. Be Wve POSTGLACIAL FAULTS OF EASTERN NEW YORK vs locations are exposed for 25 or 30 feet; and it should be remarked, that they do not occur in the vicinity of a ledge, a cliff or steep hill- side of rocks, or upon the side of a hill, but upon a level surface upon the summit.* Mather? also reported another locality east of the Hudson near Hyde Park. He states that The smoothed and scratched greywacke or grit was observed on the ridge east of Hyde Park; and about half a mile east of the post road opposite to half a mile north of De Graff’s Tavern, the grooves and scratches, which were perfectly similar in size, depth and direction, were interrupted by slips or slight faults of the rock since the scratches have been made. Professor Cas- sels observed them in several places in that vicinity. The edges of the rock, both above and below, on the slip, were sharp, and the grooves and scratches of the lower mass were continuous plump up to the surface of the upper mass; and on the upper mass they were continued quite to the sharp edge along which the slip has taken place. This type of relatively recent faults appears next to have been seen and described by Mr G. F. Matthew_as occurring in a very pronounced manner in the environs of St John, New Brunswick. The Cambric slates of the upper division of the St John group are described by him as being cut by n. e. and s. w. faults, with a hade varying from 60° to 80° s. e. There are also diagonal faults extending north and south, and east and west. In the city of St John, the faults vary in downthrow from % inch to 4 inches, the downthrow with one exception being on the north. In one locality Matthew found the sum of the displacements to be 5 feet 8 inches. He has published a photograph showing the character of the faulted surfaces.® Matthew noted the reversed character of the faults and sup- posed the movement to be due to a failure of support beneath, or to a lateral thrust from the southeast, with his preference for the latter view, in support of which he cites the ancient moun- tain-building pressures acting in this direction. He also notes the pressure acting on the rocks at Monson, Mass., reported by Niles, and the occurrence of slight earthquake shocks near St John, N. B., as evidence independent of the faults that the earth’s crust in this part of the continent is yielding under strain. 1Mather, W. W. Geology of New York: Report on First District. 1843. p. 156-57. 20p. cit. p. 387. Locality not visited by J. B. W. 8Post-glacial Faults of St John, N. B. Am. Jour. Sci. Ser. 3. 10904. 48:501—-3, pl. 11. Also Movements of the Earth’s Crust at St John, New Brunswick, in Post-glacial Times. N.B. Nat. Hist. Soc. Bul. 12. 1804. p. 34-42. 8 NEW YORK STATE MUSEUM Another district in this geologic province in which postglacial faults have been described lies along the northern border of Ver- mont and New Hampshire in southwestern Quebec. Mr R. Chalmers of the Geological Survey of Canada has recently described numerous and yet more pronounced instances of these dislocations in the Cambric and Cambro-Siluric slates of that field, viz, in the southern part of the seigniory of Aubert Gallion; at St Evariste de Forsyth, Beauce county; east of Jersey Mills; near the mouth of Gilbert river, at MacLeod crossing, Canadian Pacific Railroad; east of Scotstown; between Sherbrooke and Stoke Centre, etc. Some of these localities are shown on the accompanying sketch map [pl. 1]. The prevalent downthrows are stated to be toward the north, but throws on the south or southeast occur. Chalmers reports instances of dislocations of from 4 to 6 feet. He states that the faults in this district “ seem to have occurred near some ridge or mountain or mass of resisting rocks, the downthrow being usually on the side towards it, or rather the sliding up of the slates has taken place on the side farthest from it.” + An instance in New Hampshire noted by Professor trees is referred to in the following pages. The above .citations show that there is a group’of postglacial faults found in the belts of Cambric and Lower Siluric slates over a large area with a dominant upthrow from the southeast. Personal observations The following notes serve to show the character of the locali- ties cursorily described by Mather and the details of examples recently discovered. The localities which appear not to have been earlier described by others are as follows: South Troy, Rensse- laer, Defreestville, and Pumpkin Hollow.. The position of these places is indicated by the locality marks on the accompanying sketch map [fig. Ir]. Faults in South Troy. An instructive locality of small post- glacial faults was to be seen in the summer of 1904 in the south- ern part of Troy, on the east bank of the Hudson gorge, south of the Poesten kill. At this point the Albany clays have been largely stripped off from the basal portion of the slate wall of 1Chalmers, R. Report on the Surface Geology and Auriferous Deposits of South-eastern Quebec. Geol. Sur. Can. An. Rep’t. Pt J. 18098. 10:9j—12}j. SNK TROYAK DEFREESF VILLE. ! J t \ ZACOPAKE. e | @HYDE PARK. i I N 2 Map showing localities of postglacial faults in New York, New Brunswick and Quebec. Compiled from Mather, Matthews, Chalmers and maps by J. B. Woodworth, 1904 POSTGLACIAL FAULTS OF EASTERN NEW YORK 9 jaan a y | oY Fig. 1 Sketch map of New York east of the Hudson. The quadrangles with names correspond to the units of the State map. The localities at which postglacial faults have been seen are marked by a dotted circle. the gorge, and a quarry has been opened north of the end of Munroe street for the purpose of obtaining the sandstone which is here caught in the axis of a complicated synclinal fold bounded Io NEW YORK STATE MUSEUM east and west by fragile black shales with a somewhat slaty structure [see pl. 2]. Near the base of this slope, or from about 20 to 60 feet above the level of 4th street, the surface of the rock appears in a well glaciated area broken by postglacial faults, or at least by faults which interrupt the glaciated rock surface. The strike of the sandstones and slates is here 9° east of north, and the glacial striae run up the bank on a course s. 21° e. The dip of the slates is approximately 40° e., where not involved in the abrupt curvatures of the folds. The faults here referred to occur, so far as my observations go, altogether on the eastern side of the sandstone beds in the axis Fig. 2 Cross-section of the left bank of the Hudson south of the Poesten a in Troy, N. Y. showing position of postglacial faults in relation to river bank of the syncline. A rough sketch of a portion of the faulted sur- face is shown in figure 3, in which there is no pretension to accuracy of measurement. pies roe Below the area shown in figure 3, there is an imperfectly shown slip of 6 inches, the greatest throw I have measured in eastern New York. The faults which traverse the area mapped meas- ured, in the order in which they are encountered in ascending the slope, 5, I, 1.5, and from 2 to 5 inches. Thus within 30 feet measured up the slope there is a drop of 12 inches to the west on these faults. All of the faults observed at this locality are of the reverse type, with a steep dip to the east and a downthrow to the west. With one exception the faults are closely parallel to the steep dip of the stratification of the beds, though it is noticeable that there is a tendency of the fractures to depart from the bedding of the fine, black, fragile, shaly beds. One break extends practically at right angles to the bedding with an uplift on the north [see pl. 3]. Two of the fractures shown in the sketch converge southward and die out within the limits of the exposure. The other principal faults are traceable to the edge of the clay deposit. Their full extent in that direction is unknown. Plate 2 quarry near end of Munroe street in South Troy; looking south. Photo by J. B. Woodworth. Broken svnclinal fold in POSTGLACIAL FAULTS OF EASTERN NEW YORK Il These faults appear to be limited to the fragile shales or slates lying on the eastern side of the sandstone body above mentioned. \y nl aa F: a ee a > > nO at Z aed ENT TTP ae BE STRATIGRAPHIC RELATIONS OF THE ONEIDA CONGLOMERATE 33 of Eaton,” “gray band of Rochester”; being a sandstone to the west, and a conglomerate and sandstone to the east. In the final report of the district geologists, Vanuxem alone defined the Ontaric system as above stated. _Hall and Emmons included the Oneida conglomerate as the highest member of the Champlainic system and the Medina sandstone as the lowest member of the Ontaric or Upper Siluric. Mather, however, was more in harmony with Vanuxem and the Shawangunk con- glomerate [p. 2] alone was included in the Ontaric system. However, the other members present albove the conglomerate were referred to by Mather as the [p. 353] “ pyritous strata and red shales and grit.” In his report [p. 2] this conglomerate is designated the “ Oneida or Shawangunk conglomerate.” In a “ Review of the New York Geological Reports,” contained in the American Journal of Science [Ser. 1. 1844. 47:354], the writer of the article follows Emmons and Hall and includes the Oswego sandstone and Oneida conglomerate in the Champlainic division and the Medina sandstone is made the base of the Ontaric. In publications following the final reports of the district geolo- gists, the Oneida gradually came to be regarded as belonging to the Ontaric, to which place it had been assigned by Vanuxem. Among the reasons advanced for regarding the Oneida as Ontaric was the presence of Fucoids, either identical or closely ditied with Arthrophycus allechaniensis, a fossil very common in the upper portion of the Medina sandstone. On the other hand, the stratigraphic position of the Oneida given by Vanuxem as above the Medina has, in the past, not been retained. In nearly all publications from Vanuxem’s report to the present time, the Oneida when considered as a distinct formation has a position below the Medina. In this connection it is interesting to note that in a letter to one of the editors of the American Journal of Science [Ser. 2. 1864. 38:121], Col. E. Jewett, — states that he has found Arthrophycus. har- lani, a characteristic Medina fossil, in the Oneida conglomer- ate, near Utica, Oneida co., N. Y., and also as he observes, for stratigraphical reasons, that the Oneida conglomerate is in fact only a northern portion of the Medina sandstone. The occurrence of this or a related fucoid is stated by Dana in his Manual of Geology [1863, p. 230], a specimen having been obtained from the rock near Utica by the author more than 30 years since, which was in all probability of the same species, although, as -(tDana, J. D. Manual of Geology. 1863. p. 231. 34 NEW YORK STATE MUSEUM the specimen was afterward lost, the fact is given in the Manual with a query as to the species.” It is a noteworthy fact that in reviewing the works which have been published relating to the Oneida conglomerate and specially those which consider the Oneida as below the Medina, one can scarcely find anywhere a reference which attempts to show or even infer that Vanuxem’s conclusion was not a correct one. It is also not an easy task to show specifically how the Oneida came finally to be regarded by geologists as lying below the Medina. It should be mentioned, however, that the Shawangunk grit was regarded by all the early geologists as the stratigraphic equivalent of the Oneida conglomerate—a correlation which no longer holds good, the two terms being used as synonyms. Since we have red shales lying above the Shawangunk conglomerate, the same condition may have been assumed for central New York and thus the order of the beds determined. Again the overlapping of the upper part of the members of the Ontaric system in central New York was formerly regarded as a thinned portion of the whole formation and not of the upper part alone as is now known to be the case. The critical section for the stratigraphic position of the Oneida conglomerate is along the Oswego river. At the mouth of the river and along the shore of Lake Ontario we find the typical gray Oswego sandstone. Above the city and along the river banks, one can see that above the Oswego sandstone we have the red sandstones and shales of the Medina. These rocks show at intervals, and are specially well shown 12 miles farther south at the city of Fulton, at which place we have the falls of the Oswego about Io feet in hight. The fall is due to the resistant character of the rocks and an examination shows that the rock is a quite coarse conglomerate, in which the fossil Arthro- phycus alleghaniensis is found in great abundance and in a fine state of preservation. The rock above the fall can not be observed but enough is known to show that the conglomerate is not far below the Clinton formation. In New York, the fossil Arthrophycus alleghan- iensis Harlan is found in the Oneida conglomerate near Utica, at its type section in Oneida county, at the falls of the Oswego, and in the upper Medina west to the Niagara river. It is also found in Canada. Throughout this section this fossil is practically limited to the upper portion of the Medina and is thus important as an horizon marker. The presence of this STRATIGRAPHIC RELATIONS OF THE ONEIDA CONGLOMERATE 35 fossil and the stratigraphic relations of the Oneida conglomerate as shown in the Mohawk valley can leave no doubt of the upper Medina age of the Oneida conglomerate. Mie presencerot the fossil Ayrthrophycus alleghan- iensis MHarlan in Pennsylvania, Maryland and Virginia is of special interest. WVanuxem? in referring to Pennsylvania says: There this fossil appears in the same position, and in sand- stone of like diversity of character as to color, etc., as in New York generally. It is abundant on the Juniata, and on the west branch of the Susquehanna. I found this remarkable fossil in Virginia, about 15 years ago, near the top of the Flat-top moun- tain, a little to the west of the Salt valley above Abingdon. It was in white sandstone, which caps that mountain, and which rests upon a red sandstone reposing upon a gray or olive cal- careous sandstone containing numerous testaceous fossils, refer- able rather to those of the sandstone shale of Pulaski [=Lorraine], than to any other part of the New York system. The later work by Stevenson? also shows that this fossil is found in the upper Medina of Pennsylvania. In Maryland® the lower portion of the Medina is known as the Juniata formation and the upper portion as the Tuscarora forma- tion. No fossils are mentioned as coming from the former and Arthrophycus is the only one mentioned as occurring in the latter. The Tuscarora is regarded as, “ perhaps nearly identical with the White Medina of the Pennsylvania and New York surveys.” In Wills Creek gorge in Maryland, Professor Schuchert?* has constructed the following descending section for the Medina. I Tuscarora. Snow-white to light gray quartzite, in places a fine conglomerate; Arthrophycus harlani the only fossil—287 feet. 2 Juniata. Interbedded dull red sandstones and shales. In Wills Creek gorge 530 feet can be seen, but the total thick- ness, on the basis of that in Bedford county, Pennsylvania, is probably not less than 730 feet. 3 “Hudson River shales.” From the above it will be seen that the fossil Arthrophy- cus alleghaniensis Harlan. wherever known, is most characteristic of the upper Medina and appears to be practically confined to this horizon and that from both stratigraphic and paleontologic reasons, the Oneida conglomerate is to be con- sidered as a part of the upper Medina. IGeol. N. ¥. 3d Dist. 1842. p. 71. 22d Geol. Sur. Pa. Rep’t of Progress. T2. 1882. p. or. 3Md. Geol. Sur. Allegany Co. t1900. p. 86. 4U.S. Nat. Mus. Proc. 109003. 26: 424 36 NEW YORK STATE MUSEUM In another work, the writer? has described the Medina of New York under two divisions, namely the lower and the upper, which may be regarded as corresponding to the Juniata and Tuscarora of Pennsylvania and Maryland. The passage from the lower to the upper is marked by a change in character of sedimentation and in the color of the rock. At the Niagara river, the lower red shales are followed by about 25 feet of gray quartzose sandstone. This bed of sandstone corresponds ap- proximately to the base of the Oneida or upper Medina from Oneida county eastward, both occurring at a little more than 100 feet below the base of the Clinton. This gray sandstone marks the introduction of marine life into the Medina. At Niagara the gray quartzose sandstone is followed by a series of thin shales and sandstones and is terminated above by the “gray band” which is the upper limit of the Medina. It was pointed out in a previous paper? that the Shawangunk conglomerate of eastern New York, probably represented an © age later than the Oneida, with which it had been generally correlated. Though at that time the Oneida conglomerate was regarded as of the same age as the Oswego sandstone, the pres- ent study shows still more clearly that the Shawangunk con- glomerate should not be regarded as basal Medina, but as Salina.® In a recent publication, Dr. A. W. Grabau has regarded the Oneida as a basal conglomerate, which, in age, ranges irom the lower (=Oswego sandstone) Medina to the upper Medina. In this connection it should be noted that at the type locality for the Oneida, which is near Verona in Oneida county, the con- glomerate is just below the Clinton and that this relation to the Clinton holds for 40 miles eastward to beyond Vanhornsville in Herkimer county, where is shown the last known exposure of the Oneida to the east, and thus this formation throughout this. extent must be of upper Medina age. This fact, together with the Oswego river section, tends to show that the Oneida wherever known holds a position which is. never far below the base of the Clinton. Hall’ records the find- ing of a conglomerate or pudding stone at the top of the Medina at Wolcott in Wayne county. A similar reference is also made to this locality in one of Hall’s district reports. As the top of 1N. Y. State Mus. Bul. in press. 2N. Y. State Pal. An. Rep’t. 10903. p. 346. : 3The reasons for considering the Shawangunk conglomerate as of the age assigned above, are stated in a paper on “‘The Siluric and Lower Devonic Formations of the Skunnemunk Mountain Region” in this bulletin. 4N. Y. State Mus. Bul. 92. 1906 p. 123. 5Geol. N. Y 4th Dist. 1843. p. 42. 6An. Rep’t 4th Dist. 1838. p. 325. —————— STRATIGRAPHIC RELATIONS OF THE ONEIDA CONGLOMERATE 37 the Medina is but a few feet above the lake at Wolcott, this locality probably represents the most westward extension of what may be regarded as the Oneida conglomerate. Champlainic and the Ontaric or Upper Siluric contact In all the recent publications on geology, the Oneida conglom- erate when considered apart from the Medina is made the base of the Ontaric division. The Oswego sandstone which has been considered the westward extension of the Oneida has also been generally regarded as belonging to the Ontaric. From the con- siderations which have been stated, it follows that if we regard the Oneida as the base of the Ontaric, the lower red Medina and the Oswego sandstone. must be considered as belonging to the Champlainic, or else the base of the Ontaric must be placed lower than the Oneida conglomerate. It is not the purpose of the writer to here state just where the line between the Champlainic and Ontaric divisions should be © drawn, but rather to state some of the factors which must be considered in the final solution of the problem. In comparing the results of the early geologists, it should be remembered that Hall and Emmons included the Oneida con- glomerate as the highest member of the Champlainic system and the Medina sandstone as the base of the Ontaric. Vanuxem on the other hand regarded the Oneida as above the Medina and made the gray Oswego sandstone, which is below the red Medina, the base of the Ontaric. The later works of. Hall show that he finally included the Oneida as the base of the Ontaric, but: always held that the Oneida was below the Medina. From Oneida county eastward, the Oneida conglomerate rests on the Champlainic strata and represents the base of the Ontaric as at present defined, only in the sense that it is the lowest Ontaric formation present. Ina like manner the higher Ontaric formations rest on the Champlainic strata, the farther east we go, and at Becraft mountain, the Manlius, the highest member of the Ontaric, rests on unconformable Champlainic strata. The passage of the Lorraine into the Oswego sandstone can be observed in Oswego county and has been described by Vanuxem.* It is then evident that we have no unconformity between the Lorraine and the members of the Medina formation in Oswego county. Of the condition in Pennsylvania, Stevenson? states, “the Geol. N. Y. 3d Dist. 1843. p. 2Geol. of Bedford and Fulton nes 1882. p. 92. —w 38°) NEW YORK STATE MUSEUM passage from the Lower Medina to Hudson is imperceptible, and the red or brownish red shales yield Ambonychia radiata and. Rhy weh omedllaieap axe: Stevenson regarded the Oneida as below the Medina, but mentions the fact that the Oneida at this locality is absent and that the conditions as above stated prevail. In Ohio and Indiana, the Richmond beds follow the atediae! The Richmond beds are fossiliferous and their fauna contains a number of Trenton forms. If we regard the Oswego sandstone as following directly the Lorraine in New York State, then the Richmond must, in part at least, be the time equivalent of the Oswego sandstone. At present the Oswego sandstone is regarded as Ontaric and the Richmond beds as Champlainic. It is generally held that the Champlainic period was brought to a close by the Taconic revolution. In eastern’ New York the entire portion became land, but deposition continued in the vicinity of Oswego county, since the Oswego sandstone follows the Lorraine without break. If we consider the Champlainic as being brought to a close with the beginning of the Taconic revolution, then the Oswego sandstone could be made, as it is at present, the base of the Ontaric.?, The Oswego sandstone is practically without fossils, so from a basis of paleontology alone it can not be correlated with the Richmond beds. It seems, however, that the Oswego sandstone represents a near shore condition which was unfavor- able for the existence of life but farther west the Richmond fauna flourished under more suitable conditions. The very marked paleontologic break at the close of the Lorraine is another factor in favor of making the Ontaric begin at the base of the Oswego sandstone. The absence of a Richmond fauna from this section of New York is then to be accounted for by the changes in conditions of sedimentation rather than by an hiatus at the close of Lorraine time. There is a possibility that a fauna closely allied to that of the Richmond may yet be found in New York, in which case it would have an important bearing on the subject. ‘The pres- ence of such a fauna, however, is considered not very probable. 1S¢e Pal. Minn. 1807. v. 3, pt. 2, PD. Ciii. Note.—Grabau states, ‘‘If no unconformity exists between the Upper Richmond and the Mayville beds and if the latter are of the age of the Clinton of New York, the lower Medina shales of the Niagara region resting upon the Lorraine, must be of Richmond age.”’ N.Y. State Mus. Bul.92. 1906. p. 124. 2The value of subsidences and emergences as a basis for stratigraphic classification is stated by Ulrich and Schuchert in the annual report of the New York State Paleontologist for 1901, Pp. 650-6 UPPER SILURIC AND LOWER DEVONIC FORMATIONS OF THE SKUNNEMUNK MOUNTAIN REGION BY ClA SHARITNAG EL Introduction The Upper Siluric and Lower Devonic formations of the Skunnemunk mountain region, in the vicinity of Cornwall, Orange co., N. Y., are the extreme northeastern portion of a great outlier of rocks which extends from near Cornwall station southwestward into New Jersey for a total distance of about 50 miles. The general structure of the rocks of this area is that of a great syncline which is, however, much modified by secondary folds and by faulting. The trend of this syncline is parallel to, and 23 miles southeast from, the main area of the formations of similar ages, which outcrop approximately along a line extending from Rondout, N. Y., southwesterly through Port Jervis and continuing into New Jersey. Near the northern extension of Skunnemunk mountain, the Moodna river flows in a direction a little north of east. On reaching the end of the mountain, the river abruptly turns and flows southeasterly, in what is apparently a fault valley and across the strike of the Upper Siluric and Devonic formations. The river then again turns and flows towards the northeast and finally empties into the Hudson river at Cornwall-on-the-Hudson. Within the V-shaped area made by the somewhat unusual _ course of the Moodna river, there is a comparatively small syn- cline, and it mainly is to this section that this paper will be restricted. Previous work on this area. The rocks of this section have been differentiated since the early days of the New York State Geological Survey. Forming as they do an outlying area, they have naturally offered to the geologist an opportunity for care- ful comparative stratigraphic and paleontologic work. Hor- ton was the first to give an account of this district [An. Rep’t. lIdlewild is the name of the postoffice at Cornwall station on the Newburgh branch _of the Erie Railroad. This station is but a few hundred yards from the cut on the Ontario and Western Railroad. The nearest station of the latter road is at Orr’s Mills less than ? mile away. 4O NEW YORK STATE MUSEUM Ist Dist. 1839. p. 151]. Later his views are quoted and dis- cussed by Mather.1. Prof. W. B. Dwight? has studied the region, specially the locality of the Townsend iron mine, to which refer- ence will be made later. N. H. Darton,** in two papers, has given in detail some of the features of this area, and specially a good account of the New Scotland (=Delthyris shaly) fauna. Dr H. Ries®?-and E. C. Eckel,® have-also brietly disenssed the region. Recently Kimmel and Weller’ have published a section of the formations exposed in the cut near Cornwall station. The work to which this paper relates was taken up, partly with a view to the determination of interesting; though unexplained, conditions of overlap or faulting which had been noted by pre- vious writers, and partly for the study of some of the Upper Siluric strata of whose age here as in other sections of the State there has been ground for some uncertainty. In carrying on this work the writer has had the advantage of suggestions and advice from Dr A. W. Grabau of Columbia University. To Dr C. P. Berkey, also of Columbia, are due thanks for assistance in the determination of field measurements and structural features. Structure of the syncline. In the cut of the Ontario and West- ern Railroad, the syncline can be best observed. Here the dis- tance between the top of the Shawangunk conglomerate as developed in the two limbs of the syncline is less than 500 yards. In the east cut the dip does not vary more than 2° from the ver-_ tical and the strike is n. 9° e., while in the west cut the dip is 75° s. e. and the strike is n. 40° e. The strike of the rocks as thus measured in this cut indicates a rapidly spreading syncline. In following along the strike of the outcrops, for 34 mile, it is found that the limbs of the syncline are 24 mile apart and that, with the exception of some local changes where faulting has occurred and to which reference will be made later, the dip of the rocks has varied little from that observed in the railroad cut. From the nature of the fold, the rocks as shown in the cut can extend but a short distance to the northeast. The topographic relations indicate that they soon fail and the underlying rock is the “ Hud- son River” shale. To the southwest, after about a mile, the formations of the syncline as exposed in the cut disappear in the low swampy ground. At about the point where the lower formations fail, 1Geol. N. Y. ist Dist. 1843, p: 351, 362, 400- 2Vassar Brothers Inst. Trans. 1883-84. 2:74. 3Am. Jour. Sci. 1886. 31:209-16 4Geol. Soc. Am. Bul. 1804. 5:379-80. 5N. Y. State Geol. rs5th An. Rep’t. 1808. p. 426-28. 6N. Y. State Geol. An. Rep’t. tIg00. p. r147—-40. 7™N. J. State Geol. An Rep’t, 1901. 10902. p. 17. JY SII oy} 3e SuOTPeULIOJ AIIOY Joye PUv [[LY{SeTqOD “4jo] 7e SULT] -10]@M JNOpuOY “A ‘N ‘UOlL4S [[PMULOD ‘pROIIeI UId{SOM\\ ® Ol1eZUGQ Jo 7nd ut ‘ourjouAs Jo qu] ysvo “eYLIYS [VOT}IO A . I oyeIq FORMATIONS OF THE SKUNNEMUNK MOUNTAIN REGION 4! midway between the outer faces of the syncline, the Oriskany and Cornwall (=Monroe) formations rise as a high elevation known as Pea hill. This hill extends about a mile to the south where, at its base, the Moodna river flows and which, as already indicated, cuts off this area from Skunnemunk mountain. At first sight it would appear that this trough is a pitching syncline, and its present condition produced as a result of greater erosion of the northeast end which here would bring the two limbs close together. This, however, can be regarded as only one of the factors which indicate a spreading fold. The nearly vertical strata in the railroad cut are conditions which could not have been brought about by any method of erosion alone, but it must be concluded that the narrowness of the fold at one end is indicative of an originally spreading foid and, therefore, that its present appearance is not due simply to erosion. As the axis of this fold passes considerably to the east of the axis of Skunnemunk mountain, it is regarded rather as a local development and not an extension to the northeast of the main syncline which forms Skunnemunk mountain. Geological formations. The rocks involved in this area from the top downward are as follows: Cornwall (=Monroe shales of Hamilton age) Oriskany sandstone Port Ewen (?) limestone Eee: Becraft (?) limestone era New Scotland limestone | Coeymans limestone Manlius limestone Rondout waterlime Cobleskill and Decker Ferry limestones elipucs Siluric Binnewater quartzite ee shales (Ontaric) High Falls shale | a4 Shawangunk conglomerate of Darton fer uesen: WiveD SHALES is oly ass oe Lower Siluric (Champlainic) Cornwall shale. For reasons stated below. this term is used in place of the name Monroe shales which was introduced by Darton? to designate the shales carrying a sparse Hamilton fauna, which are well developed in the towns of Monroe and Cornwall in Orange county. In view of the fact that the name “ Monroe beds” had been used by Dr A. C. Lane to include all the rocks between the Niagara and Dundee limestones of Michi- gan, and also since there was some doubt as to the validity of the Michigan name, Professor Prosser submitted the matter to 1Geol. Soc: Am. Bul. 18094. 5:374. 42 NEW YORK. STATE MUSEUM the Committee on Geologic Names of the United States Geo- logical Survey, which sent the following reply?: The Committee on Geologic Names on May 12th took action on the validity of the term Monroe in several publications of 1891, 1892 (1893), and 1895, as the name of a group of rocks - distinguished in southern Michigan, as against the standing of the name published in 1894 for a shale formation in southeastern New York. The committee recommended that the Monroe group of south- ern Michigan should retain the name, and this action has been approved for official publications of the geological survey. The conclusion was reached on the ground that priority and prescription, or established usage, are combined in the Michigan application of the term in such a way as to make its continued use more desirable than that of Monroe shale in New York; but the case was not considered one in which priority was so definitely obvious as to justify the conclusion on the ground of the publication of 1891-92 (1893) only, since in that publication the definition was inadequate. The Cornwall? shales are well shown at Pea hill where they have a thickness of at least 200 feet. They here appear as two steep ridges, which seem to conform to the synclinal structure of this area and form the highest points on the map east of the Moodna river. These shales are dark gray in color and in places a pronounced slaty cleavage is shown. The number of fossil species found in them is small, but the number of individuals of the same species is quite large. The best localities for collect- ing are in the old vineyard and the woods on the south side of the east cliff, and on the steep western face of the west cliff. The fossils found are usually distorted and not well preserved. Darton? mentions a locality on the south side of Pea hill where is an inconspicuous outcrop of fine grained red and gray sand- stone in which the following genera were observed: i: Chonetes 5 - Spiciter 2 Meristella 6 Tentaculites 3. Orthis 7 ‘Theca 4 Rhynchonella Oriskany formation. So far as is known the Oriskany lies directly below the Cornwall shales in Pea hill. The contact between these formations at this place has not been observed, so it is at present impossible to tell the exact nature of the rock which directly overlies the Oriskany. In New Jersey, Kummel 1Geol. Sur. Ohio. ro05. Ser. 4. Bul. 7, p. 26. : a ¥, 2The expression Cornwall limestones has been used by Eckel to designate the limestones ot this area which in age range from the Decker Ferry to the New Scotland. He says, ‘‘the term ‘Cornwall limestones’ is not here proposed as a formation name, but is used merely as a con- venient designation for the series till further field work shall have decided the extent to whick subdivision can be carried.” N. Y. State Geol. An» Rep’t. 1900. p. 1148. 3N. Y. State Geol. 15th An. Rep’t. 1895. Dp. 417- ‘ec. zy Be * ur LO} NILATING || Y eee et | "= fe } : | | | [ } , ; f I ) | f ly f | = eh ~ Ma i. at Pras war Go. ake ee he " f£ i i i y ae pn > P es | ~ sh >» > _ ee Sits % a ALNOOOD AWONVUO NOLLWLS "TIVMNYHOD LOOPV NOIOWYH Ae, ELL LO CEVA. ODay EV DTT : \\\ jaseuzie “y "> Aq ABojoay eg * FoR ~ LSISNOTOLNOGIVd ALVLS AMUVIO W NHOD INANLYVdad NOILYONdga “MHOA MON 40 HLIVLS AHL me ALISYUAAINN sopeys JaATY UOSpny a _|IS 83MO7 ees A ee UNIVERSITY OF THE STATE OF NEW YORK Q y d Ts STATE PALEONTOLOGIST EDUCATION DEPARTMENT. BULLETIN 107 LEGEND Cornwall shale Oriskany” quartzite DEVONIC New Scotland beds es Coeymans limestone Manion limestone AG Rondout waterlime Cobleskill and Deckerferry limestones UPPER SILURIC Longwood shale Shawangunkk conglomerate XX Hudson River shales LOWER SILURIC Geology by C. A. Hartnagel STRATIGRAPHIC MAP —- OF THE = SS REGION ABOUT CORNWALL STATION ORANGE COUNTY ° % : © mile -- ae mai tl SER aS. re ie FORMATIONS OF THE SKUNNEMUNK MOUNTAIN REGION 43 and Weller’ have designated as the Newfoundland grit, a formation which is transitional into the Cornwall shale and which has an estimated thickness of about 215 feet. The fauna? of this grit is essentially that of the Onondaga limestone of New York. The Newfoundland grit? as defined by Kiimmel and Weller is as yet known only in the Green Pond mountain region. The relations between the Newfoundland grit as defined by Kummel and Weller and the Oriskany quartzite of the Skunne- munk mountain region is not entirely clear. In the New Jersey section under consideration, none of the Helderbergian rocks. are shown, the highest known formation below the Newfound- land grit being the Decker Ferry beds, the upper part of which corresponds to the Cobleskill limestone. For the New York area I have retained the name Oriskany quartzite, which term has. been used by Darton and by Ries for this quartzite in this region. For the present at least the retention of this term seems the most desirable, for the Helderbergian rocks, if not in actual contact with the Oriskany, are but a short distance below it. Moreover pie utiaruzite vat “Pea, hill 4s; characterized. by such Oriskany species as Anoplia nucleata Hall, and ie pio core hi 2 Plabellites Conrad. Aceordme to’ Kimmel and Weller the Newfoundland grit grades upward into the Monroe shales, without any line .of denrarkation. Two species from” the Newtoundland beds, P-terinea flabellum Conrad and Mmerinopteria -decussata Hall, as identified: by Kium- mel and Weller are Hamilton forms and they tend to show a close relation of these beds to the Hamilton formation. It is possible that future studies will indicate that the formation which I have here designated the Oriskany may represent a later return of Oriskany conditions and its fauna. In this connection it should be noted that the Esopus, Scho- harie and Marcellus formations which in the typical New York sections lie between the Oriskany and Hamilton formations, have as yet not been observed in the Skunnemunk mountain region.* The section that approaches most closely to the conditions of the Oriskany as found in the Skunnemunk region, both as regards. nature of sediments and relation of the overlying rock, is that of central and western New York, which also includes the type section for the Oriskany sandstone. There the Oriskany, wher- 1Geol. N. J. An. Rep’t. 1901. p. 18. 2N. J. Geol. Sur. Rep’t on Paleontology. 1902 (1903). 3:10 3The term Newfoundland quartzite was first proposed by Eckel for the quartzite typically exposed at Newfoundland, N. J. _ Eckel considered the rock to be paleontologically equiva- lent to the Oriskany quartzite. See N. Y. State Geol. An. Rep’t. 1900. p. r148. 4See Ulrich & Schuchert, N Y. State Pal. An.Rep’t. roo1. p. 654. ~j4 NEW YORK STATE MUSEUM ever found, is always followed by the Onondaga limestone and west of Syracuse rests upon the Upper Siluric strata. The varia- tions of the silicious and calcareous sediments and of the varying thicknesses along different meridional sections, as also the con- ditions of sedimentation and distribution of the fauna of the Oriskany of New York, have been stated in detail by Clarke.* The Oriskany formation in the area studied outcrops at the . highway which crosses the north end of Pea hill and extends into the fields below. It has a thickness of at least 50 feet and it may be much thicker. The beds are light gray in color and very massive and in some of the layers pebbles are abundant. ‘The rock is-very hard and fossils are few and not readily obtained. ‘The following have been recorded by Darton from this locality: Anoplia nucleata Hall Leptaena rhomboidalis Wilckens Leptocoelia flabellites Conrad Stropheodonta, sp ? Port Ewen and Becraft limestones. These formations, which normally come in between the Oriskany and the New Scotland beds, are not definitely known in this section. There is a covered space between the New Scotland. and the Oriskany, but the ground is mostly low and swampy and not favorable for deter- mining the nature of the intervening formations. There are, however, a few outcrops which doubtfully may be referred to the Becraft. The structural relations in this area, between the Oriskany and the New Scotland beds, suggest that faulting may have taken place. New Scotland limestone. This formation is exposed in both limbs of the syncline. In the west one there are small expos- ures in the woods south of the railroad cut. In the east limb it is exposed at several places and specially where pits have been dug for limonite, to which reference will be made later. This formation is the highest that can be observed for 34 mile south of the railroad, the interval between it, as exposed in the two limbs of the syncline, being occupied by a swamp. The entire thickness of the formation could not be measured, but its exposed thickness is not less than 40 feet. These beds are very fossiliferous and shaly, and from % cubic meter of shale Darton* collected more than 40 species. Coeymans limestone. This formation is but obscurely shown in the west limb of the fold. There is a small exposure in a depression just south of the railroad. Other unimportant expos- ures are seen in the woods beyond. The formation is best shown IN. Y. State Mus. Memoir 3. tr900. p. 65, 75, 78- 24m. Jour. Sci. 1886. 31: 214. FORMATIONS OF THE SKUNNEMUNK MOUNTAIN REGION A5 in the east cut where its thickness is 40 feet. This. probably represents the entire thickness, as the upper portion begins to show New Scotland characteristics. The upper part is a very coarse, porous, cherty limestone and contains abundant fossils. ‘The lower part is not so cherty and has more of the aspect of the Manlius, though it also has many fossil remains. Near the base of the formation the rock contains fragments strikingly similar to the Manlius. This is of special interest as the base of the Coeymans marks the lower limit of the Devonic. Other outcrops of the Coeymans can be seen near the highway which crosses this formation farther south. It also shows in some excavations that have been made for limonite and in a small quarry south of the highway above mentioned. A little beyond this quarry the Coeymans and all the lower formations down to the Longwood shales are cut off by faulting. Manlius limestone. This formation has a thickness of 7 feet. It here appears as a massive limestone, but otherwise has the features of the Manlius. The thinness of the formation in this section is unusual and from the fact that the base of the Coey- mans contains fragments of what appear to be Manlius and also from the small thickness one is led to believe that the upper part of the Manlius has been eroded before the deposition of the Coeymans. The studies of Dr Grabaut at Becraft mountain indicate that the change from the Manlius to the Coeymans was a gradual one. Similar results have been reached by the study of the Manlius in New Jersey and central New York. Van Ingen and Clark? give evidence to show that the Manlius was slightly eroded before the deposition of the Coeymans. Fossils are rarely found in the Manlius as exposed in the cut. Holo- Ped amtiqua Vanuxem is the: most: characteristic, while iepewtattita, aktia. Conrad and) tentaculites gyra- canthus Eaton are occasionally seen. The Manlius extends south to the fault previously mentioned. The contact with the Coeymans may favorably be seen in a small quarry south of the highway. The Manlius has not been observed in the west limb of the syncline. Rondout formation. This is rather a massively bedded lime- stone with some thin partings of shale. The formation is 13 feet thick and at about the middle there is a very sandy layer about 1 foot thick. This layer shows cross-bedding and although slight it is very distinct. The upper part of this for- mation shows the distinctive sun cracks of the Rondout as IN. Y. State Pal. An. Rep’t. 1902. p. 1052-54. 2N. Y. State Pal. An. Rep’t. 1902. p. 1186! 46 NEW YORK STATE MUSEUM exposed at many other places in the State. Some Favosites were found in the Rondout at the railroad cut. The lower part of the formation is transitional into the beds below and in one of the beds near the base of the Rondout there is an abundance of Cladopora rectilineata Simpson, a fossil very charac- teristic of the Cobleskill limestone of eastern New York aut New Jersey. Cobleskill and Decker Ferry Unpseotes. The Cobleskill lime- stone was formerly correlated as Niagaran, but it is now known to be above the Salina. In this cut the Cobleskill and Decker Ferry formations will be described together since for lack of fossils it is not easy to state where the division between them should be drawn. ‘The total thickness of these two formations is 35 teet. Whe upper 30 feet are characterized by the exeat abundance ot the small coral Cladopotra «eer! line ace Simpson which gives to the rock a mottled appearance. Fossils. other than the corals were not found. This coral, it should be observed, is also very abundant in the Cobleskill and Decker - Ferry at the Nearpass section in New Jersey. In color the rock is of various shades of brown. There are seams of shaly matter between some of the more massive beds. Whe upper 1oO feet are finer grained and more subject to fracture and shattering. The lower 20 feet are more silicious and compact and in position correspond with the Rosendale cement bed as shown in Ulster county. The dower 4 feet are characterized by the absence of corals and by the presence of the following species: Atrypa reticularis Linne Camarotoechia litchfieldensis Schuchert Chonetes jerseyensis Weller Longwood shale (High Falls shale and Binnewater quart- zite). This term was introduced by Darton? to designate the red shales and light colored quartzites which in the region under consideration and in that extending farther southwestward into New Jersey, occupy a position between the Helderberg (=Decker Ferry in part) limestones and the Shawangunk conglomerate (=Green Pond): Darton states [p. ssaiien Unereeare similar shales having the same relations in Ulster county, N. Y., where they have been considered equivalent to the Clinton formation.” In 1894 Darton? published a section in Ulster county where the red shales above the Shawangunk conglomerate were designated. the Medina and the name Clinton was used for the quartzites. above the red shales. As the names Medina and Clinton were 1Geol. Soc. Am. Bul. 18093. 5: 382. 2N. Y. State Mus. 47th An. eee 1894. Dp. 530, fig. 8. FORMATIONS OF THE SKUNNEMUNK MOUNTAIN REGION 47 shown to be no longer applicable to the formations bearing these names in eastern New York, the writer has used the terms High Falls and Binnewater for Medina and Clinton respectively. The Binnewater quartzite has generally been considered as of Clinton age. This correlation was made partly on account of its similarity to some of the Clinton beds in central New York and_also from the fact that both it and the green Brayman shales formerly supposed to be of Clinton age and which underlie the Cobleskill limestone at Schoharie, contain iron pvrites.2 The reasons for regarding the Binnewater quartzites as of a later age than the Clinton have been stated in previous publications.*# The Binnewater quartzite is not well developed in the railroad cut at Cornwall. Under the description of the Longwood red shales Darton. states’: . “In this cut, which is their northern- most exposure, the upper members are light colored, thin bedded quartzites, which have a thickness of 12 feet, and closely resemble the quartzites similarly lying between the waterlime and red shales in the Rosendale cement region of Ulster county.” It is evident, however, that of this thickness all but 1 foot belongs to the Decker Ferry formation. Above the red shales there is I foot of shaly brecciated limestone, which has the stratigraphic position of the Binnewater quartzite. Immediately above this brecciated layer, characteristic fossils of the Decker Ferry are found, showing that the Binnewater is here represented by a thickness of 1 foot. The brecciated character of this bed indi- cates a local stratigraphic break which is not so clearly observed in any of the other sections studied. : In Ulster county the change from the Binnewater quartzite 160 the Wilbur limestone (]Decker Ferry in part), or to the Rosendale cement where the Wilbur is absent, is an abrupt one. ‘This change appears to be due to rapid subsidence which made the shore line at a greater distance and thus the finer calcareous deposits were laid down over the quartzites.° The studies made indicate that the Binnewater quartzite was followed closely by the deposition of the overlying limestones. In this connection it is well to note Darton’s’ statement that “The Helderberg (=Decker Ferry in part) limestone usually lies on and merges into the Longwood shales.’ Kummel and Weller® state: “The IN. Y. State Pal. An. Rep’t. 10903. p. 345, 346. Be eee Pee Reve tye op: aa 7s Se a ee 6See Grabau, N. Y. State Mus. Bul. 92. 1906. p. 125. 7Geol. Soc. Am. Bul. 1803. 5: 301. 8Geol. N. J. An. Rep’t. roo0r. p. qt. 48 NEW YORK STATE MUSEUM passage upward from the conglomerates into the quartzites, thence to the Longwood shales, and finally to the Decker Ferry limestones indicates a gradual but a steady advance of the ocean upon the land to the southeast.” In New Jersey at the Nearpass quarry section, which is just over the State line from Port Jervis in Orange county, N. Y., the Bossardville limestone is just below the Decker Ferry and below the former is the Poxino Island shale. As these two formations lying below the Decker Ferry are not found either in the Skunnemunk mountain region or the Rosendale region, they probably represent, in part at least, a deeper sea — of the Binnewater quartzite. In the railroad cut at Cornwall, the High Falls shales are Ifg feet thick, and the transition to the Binnewater is well shown. The beds are coarser below and change gradually into the softer Shales above. A few thin layers of lighter colored shale are found interbedded in the High Falls, but the shale is mostly a bright red. At the base some of the layers approach closely to a quartzite. Cleavage is often highly developed in the red shales, specially at the Townsend iron mine. ‘The shale breaks into small angular fragments which are very abundantly shown along the southern end of the east limb of the syncline. The High Falls shale is almost nonfossiliferous. The only fossils found were some crinoids stems and several specimens of a small species of lamellibranch. The latter were from the red shale at the Townsend iron mine. : Shawangunk conglomerate. This conglomerate in the Green Pond mountain region of New Jersey has been called the Green Pond conglomerate. In the section studied the conglomerate is well exposed in both limbs of the syncline. The southern end of the west limb of the syncline is a high elevation made up almost exclusively of the conglomerate. The strata are nearly vertical and in places the surface is much worn and polished hy glacial action. The measured thickness is 250 feet, which, how- ever, does not represent the entire thickness as a portion of the conglomerate is concealed. The conglomerate is exposed at the railroad cut in both the east and west limbs of the syncline and in the east end of the cut the contact with the High Falls shale can be.favorably seen. The conglomerate is characterized near the top by beds of pebbles alternating with beds of red quartzite without pebbles. The pebbles are mostly quartz and many have a diameter of 2 inches. The top of the conglomerate is marked by the last appearance of pebbles. The study of the High Falls “A ON ‘UOT}eYS [[eVMUIOD ‘ourfoOUAS JO UIT] JSOA\ *PYVIYS [VOT}IOA YIM OFVIOULO[SUOS YuNSueMeBYS JO ][IY poyeloe[4 i Se “ 5 — s : ~ > 2 eee AS FORMATIONS OF THE SKUNNEMUNK MOUNTAIN REGION AQ and the Shawangunk formations in this cut shows quite clearly that the High Falls shale follows the Shawangunk without break. The passage from the Shawangunk (=Green Pond) conglomer- ate to the High Falls (~Longwood) shale is thus expressed by Darton?: “They [=High Falls] are also everywhere intimately associated with, and grade into the Green Pond conglomerate.” Again [p. 384]: “ The quartzites grade upward into the Long- wood red shales, and the intergrading is exposed at a number of points along the west slope of Green Pond mountain and in New York. On the northwestern slope of Pine hill, beds of passage are finely exposed, and the red shale and red quartzite are inter- iiadiitdtea sor 2 thickness of several feet.” Aliso [ips 391]: ) “ The Longwood shales are not known to overlap, for they merge into: itexupper part ot tthe, Green Pond /tocks in all the: exposure.” Reference already has been made to the transition of the Shawan- gunk and the Longwood as stated by Kummel and Weller. The following is the section as shown in the east cut near Cornwall station: Feet DEVONIC Pee areeeii mS MEMES EOMEN srry a ae ttre ti tea wists 2 viv ss) cies 6 Sale oes 40° UPPER SILURIC Pee atilites Mire GbOse grate eres Ie Oe ee ak ee Shee ys Ea RpeONTIGL ONO tra ICE ELITE teen ee c9 ie ong aya aR tie aE 60 bak Bila now's 13 perecoplesikalleand Decker tery lumestones: i. u 55 oe. o3o 35 5 Longwood Pate pee eie eee tee PO Oats. Bor A Me 120: High Falls shale Spe Say are aK nCOMelOMIer abe y. has o-.6 io alaehe a-- vis nla eicre se a Mintekwess, Gr tac pper Sl uric. rocks. 2 5.7... 200: In all the early work which relates to these formations and until very recently bed no. 4 of the above table, when recog- nized at all, has been regarded as Niagaran in age. It is thus easy to see that with this correlation of the Cobleskill the lower beds which are the Longwood and the Shawangunk would natur- ally be correlated*with the Medina and Oneida respectively. In the same manner, assuming the Shawangunk to be equal to the Oneida, it would follow that the Cobleskill and Decker Ferry would be regarded as Niagaran. As we now know, however, that the Cobleskill is above the Salina and that all the lower formations follow without any break of importance as has been shown by the work of several writers, it follows that the Long- 1Geol. Soc. Am. Bul. 1803.- 5: 282 50 NEW YORK STATE MUSEUM wood shales and the Shawangunk conglomerate must be regarded as much later in age than formerly supposed and as has already been suggested, the Shawangunk in this portion of the State represents the invading basal member of the Salina. Recent determinations have shown that the Oneida conglom- erate is no longer to be considered as the basal member of the Medina, but that it belongs to the upper part of the Medina series. This determination in regard to the higher stratigraphic position of the Oneida demonstrates to a certain extent that the Shawangunk is not to be regarded as basal Upper Siluric.t The higher stratigraphic position now assigned to the Oneida makes the time interval between the Oneida and the Shawangunk conglomerates less than formerly supposed when the Oneida was considered as basal Medina. Some of the reasons for con- sidering the Shawangunk as of Salina age have already been given. Other reasons are as follows: The Shawangunk con- glomerate rests on folded and eroded “ Hudson River” strata. That extensive folding and erosion had taken place previous to the deposition of the Shawangunk is shown by the fact that in some places these agents have brought to view exposures of rock which from the faunal contents are regarded as the Nor- manskill shale of middle Trenton age. The presence of Lor- raine beds shows that deposition had continued until the close of the Lorraine and therefore, to allow time for the folding and erosion of the strata previous to the deposition of the Shawan-_ gunk, we must regard this conglomerate as of later age than the Oneida. The almost noniossiliferous character of the strata below the Decker Ferry beds indicates that they were formed during Salina time rather than during the Niagaran period. The period of the Shawangunk conglomerate was one of increasing submergence? and on the east side of the Helderberg the suc- ceeding formations progressively overlap the “ Hudson River” shales until finally at Becraft mountain the Manlius, the highest member of the Upper Siluric rests unconformably upon the “‘Hudson River” shales. From these conditions of overlap as shown on both the east and west sides of the Helderberg the evidence is in favor of regarding the Shawangunk as Salina, since the latter on the western side of the Helderbergian barrier extends much farther east than does the Niagaran and in the same way the higher formations of the Upper Siluric are to be looked for in the eastern section. 1See Grabau N. Y. State Mus. Bul. 92. p. 126 2See Ulrich & Schuchert, N. Y. State Pal. An. Rep’t. Ig0I. p. 647. FORMATIONS OF THE SKUNNEMUNK MOUNTAIN TABLE SHOWING RELATIONS OF THE REGION 51 UPPER SILURIC SECTIONS OF EASTERN NEW YORK WITH THE WESTERN NEW YORK SECTION Western New York ‘Cobleskill Salina series Port Jervis, Orange co. Cobleskill Salina series Ulster co. Cobleskill Salina series Cornwall, Orange co.. Cobleskill Salina series Previous cor- relation for |Eastern New York |} and New Jersey ‘““Niagara”’ Bertie | Decker Ferry | Decker Ferry | Decker Ferry Camillus Bossardville | (Rosendale| Syracuse Poxino Island) cement & Vernon Wilbur lime- stone) Pittsford Binnewater rabeamnie Se ei Long-| sandstone Clinton High Falls | High Falls Bee ees ELS) eee shale(?) shale ee Shawangunk | Shawangunk | Shawangunk (Oneida ‘Guelph Lockport Rochester Clinton Medina includ-|Unconformity |Unconformity |Unconformity |Unconformity ing Oneida at top and Os- wego sand- stone at base ““Hudson “Hudson ‘““Hudson ‘“Hudson ‘““Hudson River”’ River”’ River? Rives” River’ ‘beds beds beds beds beds The subdivisions of the Salina series are not intended to show exact stratigraphic equivalents as read horizontally across the page, but rather the subdivisions recognized in the different ‘sections. In Rensselaer county there is a quite extensive plateau under- lain by what is known as the Rensselaer grit. This formation has generally been regarded as basal Upper Siluric and correlated with the Oneida conglomerate or the Shawangunk conglomerate, the two latter being regarded as stratigraphically equivalent. If we regard the Rensselaer grit as basal Upper Siluric then this tegion must have been submerged shortly after the Taconic revolution. This, however, does not appear to be the case since the grit rests unconformably on strata which in age range from Lower Cambric to and including the “ Hudson River” beds.t The evidence furnished by the study of the Shawangunk grit and the Oneida conglomerate does not indicate that either of these formations extended as far as the region of the Rensselaer 1Dale, T. N. U. S. Geol. Sur. Bul. 242. 1904. p. 51. 52 NEW YORK STATE MUSEUM grit. There does not seem to be good evidence to show that the sea covered this area after the Green Mountain uplift until later Upper Siluric or Devonic time. This is made apparent when we consider that the Rensselaer grit occupies an area that was highly involved in the disturbances at the close of the Cham- plainic period. _ In tracing the Siluric formations north from Ulster county, the Shawangunk conglomerate is the first to fail, and the suc- ceeding formations fail by overlap in regular order until at Becraft mountain in Columbia county the Manlius as already pointed out rests unconformably upon the Champlainic strata. This shows that as we approach the Rensselaer grit area, only the highest members of the Upper Siluric are present, and the conditions of overlap of these formations clearly indicate that the Rensselaer grit is not of Shawangunk age. In tracing the Upper Siluric formations eastward from central New York, the Oneida is overlapped by the Clinton, and im Albany county but 17 miles from the Rensselaer grit plateau, the Manlius and a few feet of the Rondout are the only members of the Upper Siluric present. From this it does not appear that the Rensselaer grit can be correlated with the Oneida conglomerate.” The submergences and emergences, which involve the conditions of overlap following the Taconic revolution, have been stated in detail by Ulrich and Schuchert.? | Structural relations of the Townsend iron mine. The Town- send iron mine was first described by Horton® in 1839 as follows: “Two and a half miles west of Canterbury, in Cornwall, is the hematite or limonite mine of Mr. Thomas Townsend. For the last two years this ore has been considerably used and although a lean ore, it makes excellent iron. It is mostly in powder, or very small fragments, mixed with balls and pieces of the hema- tite, of a few pounds weight. It lies in a limestone rock, and between the limestone and the grit rock. These rocks where connected with the ore, are decomposed to great extent, and. mixed in a state of powder with the ore; hence the ore requires. washing.” This limestone was definitely correlated by Mather *° with what are now recognized as the New Scotland beds. He states, “The Strophomena rugosa Dalman and 5. radiata Sowerby are very common fossils at the above locality, and the 1See Dale, U. S. Geol. Sur. Bul. 242. 1904. Dp. 53- 2N. Y. State Pal. An. Rep’t, 1901, p. 647, 660. 3An. Rep’t ist Dist. 1838 (1839) D. 165. 4Geol. N. Y. 1st Dist. 1843. Dp. 351. 5See also plate 5, figure 14. UOT “A ‘'N ‘UOT}EIS [[EMUIOD Iv9U SUTUL o}TUOULT] PUSSUMO TL JYSII sy} 7 Spoq PURTIOIS MON ‘Foy oY} Fe OTVYS Por poomMs € 9%Id FORMATIONS OF THE SKUNNEMUNK MOUNTAIN REGION 53 rock is considered as belonging to the Catskill shaly limestone, which here has been upturned on its edges like the adjoining slate, grits and other rocks.” An examination of this mine was made by Prof. W. B. Dwight! who states, “that the limestones are of the lower Helderberg group, and that the adjoining red sandstone and conglomerate are not of the Triassic, like the New Jersey red sandstone, but are the Oneida conglomerate and the fine grained sandstone of the Medina epoch.” The geology in the vicinity of the Townsend iron mine has been studied in some detail by Darton.?? His reports include the stratigraphic and paleontologic determinations and maps and sections of the region studied are given. At the Townsend iron mine we find the strata nearly vertical and the New Scotland beds rest against the Longwood shales. This condition was noted by Darton, who states that it was due to faulting or thinning out of the formation below the New Scotland. In the railroad cut the formations between the New Scotland and the Longwood shales are 95 feet thick. As the Townsend mine is but 4 mile away from this cut and in the same limb of the syncline, it did not seem possible that the formation could thin out in such a short distance. On tracing the intervening formations south from the cut at a short distance south of the small quarry, just beyond the highway, the limestone formation below the New Scotland suddenly ceases and we come upon an area of red shale. The increased thickness of the Longwood Shale at this point clearly indicated that they had been faulted. There is a small depression which marks the fault line passing at an angle and meeting another parallel to the strike of the rocks. It is evident that in faulting a wedge-shaped block was forced out carrying the limestone with it, the red shales thus coming into contact with the New Scotland. The steep ridge now left standing is composed of red shales, and it appears that only in very recent times has the limestone cap been removed and thus made possible this steep ridge of red shales. There are other indications of faulting in the vicinity of the mine. In some exposures the rocks are partly overturned and the red shales show induced cleavage. From the red shales at this mine a number of specimens of a lamellibranch were obtained. With 1Vassar Brothers Inst. Trans. 1883-84. p. 75. 2Am. Jour. Sci. 1886. 31: 209-10. 3Geol. Soc. Am Bul. -1893. 5: 379. 54 NEW YORK STATE MUSEUM the exception of fragments of crinoids, these have been the only fossils recorded from the Longwood shales. The iron taken from this mine is from the New Scotland beds and along the contact of the latter with the Longwood shale. The leached character of the red shales which are adjacent at once suggests the origin of the iron. A brief description of this mine together with the following analysis of the ore is given by Putnam. Per cent Metalic iron. 1c). ascee Seek Gee ep eee ee 28:57 PMOSpl ORs 3.5 gues eee eet ee ee 0.240 Manganese. . 2 > )dacdeuhoe as. peek 5 ee eee Phosphorus. in 100 parts trols. 4) ae oe Se tg ae 0.840 A study of the geological relations at the mine shows that the presence of iron ore in the New Scotland beds is of local occur- rence and is found only where the New Scotland beds are in contact with the Longwood shales. Several openings in the New Scotland beds north from the mine, have been made, but without finding any ore. An examination of these nonproductive openings shows that between them and the Longwood shale there are at least 80 feet of limestones, which indicates that this part of the syncline has not been affected by the faulting and that further exploitation for iron, of the New Scotland beds north from the productive mine will bring only negative resuits. 1Mining Industries of the U. S. 1886, p. 127. MINERALS FROM LYON MOUNTAIN, CLINTON COUNTY By! HERBERT PP. WHITLOCK Early in the spring of 1905 the attention of the writer was di- rected by Mr H. H. Hindshaw, geologist to the Delaware & Hudson Company, to some interesting occurrences of secondary minerals associated with the magnetite deposits of the Chateaugay nuines at Lyon Mountain. A visit to the mines made in the following summer resulted in the addition to the collection of the New York State Museum of about 150 specimens from this locality. This material augmented by a smaller collection made by Mr D. H. Newland, Assistant State Geologist, and a number of fine specimens presented to the museum as well as some loaned for study by Mr Hindshaw, forms the basis of the following paper. The writer wishes to express his» thanks to the above gentlemen as well as to Thomas Cameron, at that time underground foreman, for many valuable suggestions as well as for aid in acquiring material. 3 GENERAL DESCRIPTION The Chateaugay mines are situated at Lyon Mountain in Clinton county, about 22 miles west of Plattsburg and near the northern boundary of the area of Adirondack gneiss which forms the main outlying mass of the Adirondacks. ‘The workings consist of a series of inclined shafts which in some instances extend to a vertical depth of 800 feet. It was for the most part in the deeper levels of the mine that the openings or ‘‘vugs’’ were encountered which fur- nished the greater mass of the material collected. One of the lar- gest of these now accessible, situated at the 600-foot level, was some 15 feet in length by 3 feet wide and extended vertically to an unknown hight, the bottom being filled with blocks fallen from above. The walls of this cavity, where accessible, were thickly covered with hornblende, apatite, orthoclase and titanite in large and perfect crystals as well as many of the minerals later to be described, in matrix. Most of the calcite specimens of types III, IV and V were obtained from a still larger vug which formerly 56 NEW YORK STATE MUSEUM extended across the ore body and was excavated previous to the writer’s visit. Most of the material collected from the dump heaps also showed evidence of the same vug formation. MINERAL SPECIES Molybdenite Molybdenite occurs closely associated with brown titanite in one of the smaller vugs opened on the 800-foot level close to no. 5 shaft. The specimen obtained showed one bent and distorted crystal about ro mm in diameter as well as several smaller ones, from which latter imperfect measurements were obtained which served to establish the presence of the pyramid (2021). This pyramid, as shown by Moses,’ is of comparatively frequent occur- rence on measurable crystals of molybdenite, being found on the crystals from Frankford, Pa.; Aldfield, Quebec; Cape Breton, and Okanogan county, Washington. The amphibole, titanite, phlogo- pite and quartz associated with the Lyon Mountain molybdenite showed marked evidence of partial resolution and were accom- panied by secondary calcite, stilbite and pyrite. Pyrite Pyrite occurs abundantly in detached crystals of secondary origin associated with the orthoclase, hornblende, quartz and magnetite of the wall rock in the contact zone with the ore body. They consist of small but brilliant individuals averaging about 2mm in diameter, the principal faces of which yield excellent reflections. The examination of a large number of these failed to reveal any new or unusual forms, the prevailing habit being that shown in figure 1 which is identical with that found on the pyrite from Kingsbridge.” The occurring forms are a (110), o (111), @ (210), s (321) and u (211), the two latter being present only as narrow faces. Quartz Quartz of both primary and secondary derivation occurs abund- antly in the contact zone. The primary quartz occurs in rounded masses of variable size deeply furrowed and completely covered 1Moses, A. J. Crystallization of Molybdenite. Am. Jour. Sci. 1904. 167: 350. 2Moses, A. J. Pyrite crystals from Kingsbridge. Am. Jour. Sci. Ser. 3. 18093. 45: 488. MINERALS FROM LYON MOUNTAIN, CLINTON COUNTY 57 with parallel systems of wavy lines due to partial resolution. Several of these etched nodules which were obtained in a calcite matrix represented originally detached crystals. These roughly presented the form of oblate spheroids and though extremely rough on the surface reflected back the light from minute smooth surfaces in a manner suggesting the appearance of a cleavage fragment. On orienting one of these nodules in the reflection ‘goniometer, it was found that the reflections from these corrosion surfaces in the circle of the transverse axis gave the angles of the prismatic zone for quartz. Furthermore, on reorienting the nodule, reflections were obtained from corrosion faces correspond- ing to the rhombohedral planes r (rcrzr) and z (o111) the angles agreeing fairly well with theory, considering the character of the faces measured. | Secondary quartz occurs with hematite, calcite and byssolite, all of later generation and derived from the redeposition of dissolved primary minerals, in brilliant crystals, transparent and for the most part colorless, but occasionally showing slight smokiness as well as inclusions of scaly hematite and prochlorite. A number of crystals were measured, several of which showed the rhombo- hedron T (4041) and the trapezohedrons x (5161) and q’ (10.1.11.1) the two latter being observed on right-handed crystals. In one instance a right trapezohedron was noted in the zone [orro.1121.- 1011] which gave an angle corresponding to (12.11.23.11) but as the face was not repeated on the same or other crystals, its acci- dental presence was assumed.to be due to vicinal development. Figures 2a—2b show this habit. The observed forms with the measured and calculated angles are given below: Forms | Angle Measured Calculated m toro | T IOII Zz | OIIL a ty ° , ° , af 2 4041 IOIO :4041 II II II 8 = II21 IOLO ‘1121 a0 51 a7 58 Le 5161 Iolo ‘5161 II 58 E2 i: g EOwT= PT | IOLO:10.1.11.1 6 ae 6 314 58 NEW YORK STATE MUSEUM Hematite Secondary hematite derived from the magnetite occurs associated with other minerals of the second generation such as quartz, calcite and albite. It is found in close aggregates of brilliant metallic plates of the type shown in figure 3 the observed forms being ¢ (ooo1), r (1011) and m (2243). A phase of this habit found in close association with the secondary amphibole (byssolite), is characterized by minute circular disks about 1 mm in diameter consisting of flat rosettes of thin plates. These have a red metallic luster resembling that of burnished copper and show bright cherry- red by strong transmitted light. A specimen of quartz with which these latter were associated was quite thickly covered with small hemispheres of botryoidal hematite. It is quite evident from this. specimen [pl. 8] that these three phases of the deposition of hematite belong to the same period of genesis and were deposited toward the end of the formation of secondary quartz. Calcite The several phases which mark the deposition of secondary calcite are characterized by calcite crystals of definite habit. Of these crystal types, the first two stand distinctly apart from a. genetic point of view, whereas the last three are more or less closely . related both from the standpoint of crystal genesis and habit. Type I. Crystals of this type are found directly associated with the corroded quartz orthoclase and amphibole, in most instances. deposited as a crust upon a highly corroded surface. They are distinctly scalenohedral in habit, the steep scalenohedron “ (5491) predominating, modified in termination by the rhombohedrons M (4041) and E (0.13.13.4). Figures ga-4b and sa-sb show this: habit. The rhombohedron M is present in a bright series of planes. which furnished excellent points of reference. The rhombohedrom E, on the other hand, gave faint but distinct reflections from a series of dull and somewhat rounded surfaces. On several speci- mens the rhombohedron 7 (1011) is prominent in crystals of this. habit. Several times during the measurement of crystals of this type, a narrow plane beveling the acute polar edges of (5491) was observed. A rhombohedron in this zone would have the indexes. (0.13.13.2) a form which seems doubly probable in consideration MINERALS FROM LYON MOUNTAIN, CLINTON COUNTY 59 of the fact that the presence of (0.13. 13.4) has already been noted with reference to this type. No satisfactory reading could, how- ever, be obtained. The crystals which measure from 3 mm to 25 mm in length are,, in some instances, filled with microscopic inclusions of quartz, hematite and matted byssolite, the latter forming a central nucleus. of irregular shape, while the hematite, which was connected with a later stage of the crystal growth, appears in the outer layers in dendritic bunches. Regarding the generation of calcite of this type it must be un- questionably placed at the base of the calcite series as shown at Lyon Mountain. The marked absence of pyramidal forms in the crystal habit and the presence of two modifying rhombohedra entirely absent from the varied types found in the later calcite deposition, set it distinctly apart as marking a separate genetic phase. At the same time the close association with primary minerals which show evidences of corrosion, points to the origin of this type from a highly corrosive crystallizing solution, rich im carbonate of lime but still far from saturated with silica and iron. Type II. Calcite crystallizing in the forms of type II occurs: incrusting the surface of joints in the ore body, in a confused ag- gregate of translucent, milky white crystals which exhibit none of the tendency toward parallel grouping of separate individuals. noticeable in other types from this locality. The manner of the crystal massing suggests rapid deposition from a solution whose condition of concentration had been influenced by sudden cooling, change of pressure or some allied cause. Such a change of condi- tion of concentration seems highly probable in the case of an open joint filled or partly filled with the crystallizing solution which from the nature of the case would be far more sensitive to the influence of currents. The crystals of this type [fig. 6a—6b] which average 7 mm in diameter, are rhombohedral in habit and composed of “built up’” forms, the predominating negative rhombohedron being deeply grooved by incipient modifications parallel to (ooo1) and (orr2).. The rhombohedron Y (0.19.19.13) is present as a series of moder- ately brilliant but somewhat rounded faces; the form was deter- mined by averaging the readings taken on 20 of the best crystals available. The scalenohedron q: (2461) is present, beveling the ‘60 NEW YORK STATE MUSEUM basal edges of the predominating rhombohedron. Indications pointed to a second scalenohedron in this zone giving the indexes (10.16.26.3) and beveling the basal edges of q: as thin lines from which measurements were obtained with great difficulty. ‘The form must be regarded as doubtful. Type TI. Calcite crystallizing in forms of this type differs from those previously described both in mode of occurrence and habit. They occur for the most part embedded in masses of byssolite and are often free or so loosely attached that doubly terminated indi- viduals are readily obtained. They are of a later generation than those of type I, being contemporary and closely associated with ‘secondary quartz, hematite and albite derived from the minerals accompanying type I. In habit they are essentially pyramidal, the simpler development showing the predominance of two pyra- mids in the same series, (8.8.16.3) and (2243) figure 7a, 7b. More complex variations of this habit [fig. 8a-8b] are found associated with these secondary minerals and, indeed, the remain- ing types to be discussed may be said to represent phases of the same conditions of deposition, as they are, at the same time, modi- fied expressions of the same crystal habit. The combination shown in figure 7a, 7b represents this habit in its simplest develop- ment and is found in crystals varying from 2 to 5 mm in vertical length. The pyramid y (8.8.16.3) occurs as a series of bright, sharp faces. The faces of the pyramid I (2243) and of the rhom- bohedron Y (0.19.19.13) are of fair brilliancy but frequently roughened by natural etchings. The planes of v (2 131) are often present on this combination but of relatively small development. ‘On two crystals a terminating scalenohedron in the zone [0.19.19.- I3.19.19.0.13] gave measurements roughly corresponding to (7.2.9.11) ‘but on account of the imperfect nature of the reflections the form must be regarded as doubtful. ) The combination shown in figure 8a-8b represents a modification of this habit in which the planes of the scalenohedron v (2131) partly replace those of y and a second negative rhombohedron L (0445) terminates the crystal partly replacing the planes of I. The alternate polar edges of y are beveled by the scalenohedron {l: (x4.12.26.5) in the zone [8.8.16.3.16.8.8.3]. This combination which seems to indicate a slower and more perfect stage of crystal- lization occurs in larger crystals than that previously described under this type, detached crystals measuring from 4 mm to 30 mm in vertical length. . MINERALS FROM LYON MOUNTAIN, CLINTON COUNTY 61 Type IV. Figures 9a-gb show a combination resulting from the development of the negative rhombohedron A (0443) which here replaces the planes of the pyramids y and Ito the extent of giving to crystals of this phase a rhombohedral aspect. The pyramids y (8.8.16.3) and IT (2243) which connect this combina- tion with type III are present as faces of great brilliancy, as are also the planes of v (2131). The rhombohedron A (0443) here ‘replaces Y as a series of brilliant planes which yield excellent reflections. Genetically this type corresponds closely with type III, the crystals occurring with considerable secondary quartz -embedded in chlorite also of the second generation. The crystals are clear and faintly yellow in color and measure from 6 to to mm on the vertical axis. A curious variation of this type was noted on a large mass of hornblende which was thickly incrusted with albite crystals.’ ‘These calcite crystals were symmetrically disposed in parallel position on the six basal angles of a positive rhombohedron r (1011) the latter evidently of a previous growth and considerably etched and roughened on the surface. One of these composite crystals.is shown in figures rob—1roc and an enlargement of one of ‘the superposed secondary crystals in figure 10a. The secondary crystals of this phase bear a general resemblance to the modified combination of type III [figures 8a-8b] in that they show the scaleno- ‘hedron (1: (14.12.26.5) beveling the alternate polar edges of the prevailing pyramid y (8.8.16.3). The pyramid 7 (1 123) in the same series with those previously noted appears as a terminal ‘modification consisting of deeply striated faces. The scaleno- hedron p (5491) of type I here reappears for the first time as a ‘series of small but brilliant faces. The negative scalenohedron q: (2461) characteristic of type I] ishere represented by small brilliant ‘faces; from both of these latter forms, excellent reflections were obtained. These two pyramids T (2243) and y (8.8.16.3) are developed as large faces, the former giving fair reflections from somewhat dull surfaces, and the latter bright and sharp reflections. ‘The three pyramids lie well in zone and agree closely as to measured -and calculated angles. The composite crystals as shown in figures tob—Ioc vary in size from 4 mm to 30 mm in diameter measured on a basal axis. The superposed crystals frequently unite to form a ‘band encircling the primitive rhombohedron which latter in many instances shows incipient forms of this habit irregularly disposed 1The writer is indebted to Mr H. H. Hindshaw for the loan of this handsome specimen as well -as for material taken from it for study. 62 NEW YORK STATE MUSEUM on the rhombohedral planes in parallel position; these latter, how— ever, are microscopic and only serve to accentuate the character— istic grouping habit. Type V. Crystals of this type were noted on a single specimen,,. which differed little, with respect to the association and general deposition of the secondary minerals, from the specimens producing types III and IV, but which showed a much lower percentage of secondary quartz crystals than these latter. Several small crystals. of transparent apatite were noted on this specimen. In habit these crystals are far more complex than any hitherto described from this locality, the combination shown in figures 11a—11b consisting of no less than 11 forms. In size and brilliancy they also exceed the previously described types averaging 12 mm in vertical length and beautifully developed in clear and sharp faces, all of which, with the exception of I (0445) gave fine reflections of the goni-. ometer signal. In general, indications seem to connect this type with a slower action of the crystallizing solution producing more perfect and highly modified individuals. A clearly marked rhombohedral zone consisting of 1 (0445), A (0443), f(o221), A (0772) and & (o.11.11.1) characterizes the crystals of this type, the faces of which are small but clearly defined. y (8.8.16.3) the predominating pyramid of types III and IV is wholly lacking from this combination, its place being taken by « (4483) a form not hitherto noted from this locality but which completes the series of pyramids by supplying a logical. link in the sequence between (2243) and (8.8.16.3) the former of which is present as a highly developed series of planes giving very fair reflections. Two negative scalenohedrons p: (2461), which was also noted in types II and IV, and C: (3472) are present as large and well developed forms. The positive scalenohedrons v (2131) and R: (8.4.12.1) are present as well developed forms. A regular and symmetrical roughening was noted on the obtuse polar- edges of v (2131) as shown in figure 11b which was probably due to some twinning tendency,! although no twins were observed in con- nection with this type. The complex zonal relations between the various forms occurring on the calcite from Lyon Mountain are shown in the stereographic projection, figure 12 and are particularly well illustrated in the —_——_— 1In this connection it is interesting to note that the calculated values of @ for (213 1) and (4261} differ by but 30” and that consequently a penetration twin parallel to (o0o01) would bring the superposed planes of these two forms in close orientation and might result in a vicinal roughen- ing similar to that observed. ; MINERALS FROM LYON MOUNTAIN, CLINTON COUNTY 63 22% (ax LLO 2 Ti3s . 25Oniar 43 M0 | 410 29% \.29-. 5 | 28.254 |\a:p oy | roc err lems se clos 40. m:p TLOUEM| 47-43) 47 50 ane 305 21a 132 45 |32 ty PoP) \ PILEAY W084, 25 84 ZO U:u" | 331:331 |139 35 |140 35 Viv" 221:221 [122 57 |122 12 | Epidote Epidote occurs in irregular strings scattered through the ortho- clase of the pegmatitic phase of the wall rock and usually in close association with light gray massive wernerite. In several instances phenocrysts of amphibole in a wernerite matrix were noted which showed a distinct rim of epidote indicating a probable derivation of the latter mineral from a previously deposited amphibole. Measurable crystals were obtained from small veins, where they occurred deposited on a thin layer of bluish green marmolite and partially imbedded in massive calcite which constituted the ulti- mate vein filling. These crystals which average 3 mm in length show no unusual development in crystal forms or habit. Figures 20a-20b show this habit, to which all the crystals studied con- formed with great regularity. The planes of the zone [100.001] are sharp and brilliant although frequently marred by vicinal striations. In many instances the crystals are somewhat bent. The planes of the hemipyramid (111) are rough and dull while those of the prism u (210) although extremely small are well marked and bright. The following forms were noted: a (100), ¢ (001), u (210), @ (101), r (01) and u (x11). Angle Measured | Calculated | Angle Measured | Calculated if ° / ° / 1) / ° / C.a Oot :I00 |64 34164 aH tase IOO:IOI | 29 ~~ 45] 29 54 Go. OOT ‘IOI |63 34/63 Azle | Sree aFO. S20" 7ot lag f 210:210 |Iog 7|I09 I a:r IOO:IOI |52 a =| UUM Se MINERALS FROM LYON MOUNTAIN, CLINTON. COUNTY ji Stilbite Stilbite occurs abundantly in drusy crusts and aggregates of colorless transparent crystals and in yellow to brown sheafs, all of which display the characteristic pearly luster on the clinopinacoid. The planes of m (110), usual in the twinned parallel grouping of stilbite, are here replaced by those of, the hemiorthodome f (ior) which with the pinacoidal planes ¢ (oo1) and b (o10) produce a combination varying but slightly in shape from a right parallel- opiped, and which give to the parallel groupings a flat rather than a serrated aspect. This parallel grouping is shown in figure 21. The usual penetration twins with the twinning plane parallel to c are apparent in sections parallel to b in polarized light. | Biotite Biotite in distinct crystals occurs imbedded in calcite of type 1 from a vug opening into the 600-foot level. ‘Phe crystals average 20 mm in diameter and show fair development of the planes of pu (rrr) and b (oro). A marked twinning habit with c for the com- position face was noted in a number of instances, the arrangement of the crystals being that shown in figure 22. No accurate readings could be obtained in the reflection goniometer owing to the dull and irregular character of the faces, but sufficiently close measure- ments were reached with the contact goniometer to identify the forms b (o10) and (111). A decided tapering toward the vertical termination due to “stepped”’ crystals in parallel position is charac- teristic of the occurrence. The crystals are black in color and only transparent in very thin plates. The interference figure in con- vergent light shows a small axial angle. Titanite Titanite of the variety lederite was obtained from the walls of the largest “‘vug’’ opening into the 600-foot level. The crystals which measured 3 to 15 mm on the 6 axis occur associated with ortho- clase, magnetite and quartz of the first generation. They are dark brown to black in color and show brownish red in thin sections by transmitted light. A distinct parting parallel to y (221) gave a measured angle of 125° 35’ corresponding to a calculated value nAn’ 125° 42’. The prevailing crystal habit is shown in figures 23a-23b, although in one instance a considerable development of the planes of (111) produced an elongation parallel to these planes which simulated a prismatic habit. The observed planes lie mostly 72 NEW YORK STATE MUSEUM in the zone [oor.110] and are, for the most part, brilliant and sharply defined. Vicinal developments which were noted throughout this zone are probably due to the rounding of the edges characteristic of this variety. Twinning parallel to a is common to this occur- rence, the twinning habit producing sharply defined reentrant angles between c andc. The forms observed with theit measured and calculated angles are given below: SUMMARY OF MEASURED AND CALCULATED ANGLES Form Angle Measured ’ Calculated 9° / [o} 7 Gu oor a IIo b O10 m IIo C.m OOI:IIO 65 Os | -O5 30 mm!” II0:110 66 L766 29 b.m OLO:1IO 56 46 | 56 46 n IGE Cn OOL:III 38 4 | 38 16 nn’ reTCIaM Mica 43 25 Ag 49 7] DPI c.1 OOT:221 49 i 49 15 0:10 221 :221 54 25° | 54 18 t Tir Gt OOL ‘Iti 70 174| 70 Ze) Ly gas ae 68 53.| 69 9 l 112 Gul OOL:112 40 254! 4o 34 Apatite Apatite occurs quite abundantly both as a primary mineral associated with orthoclase and hornblende in large crystallizations, and as a secondary mineral, deposited from resolution of the former phase in small crystals associated with the calcite of types III, IV and V. Both phases of apatite give distinct reactions for chlorine and fluorine. The crystals of the first generation were obtained from the vug opening into the 600-foot level which furnished the . large hornblende crystals previously described. Like these, the crystals of apatite are in many instances of unusual size, the one shown in plate 11 measuring 7 cm in diameter while many of those lining the walls of the vug were considerably larger. They show marked indications of an aqueo-igneous origin and were undoubted- ly subjected to considerable mechanical stress when still in a plastic condition. A striking evidence of this latter fact is given by the specimen shown in plate 11. In this instance heart-shaped MINERALS FROM LYON MOUNTAIN, CLINTON COUNTY 73 wedges of orthoclase have been driven into the perfectly formed apatite crystal causing a distinct inward curve of the surface around the edges of the puncture and a decided bulging of the material displaced by the injected wedge. The writer has produced a simi- lar aspect in a prism of softened paraffin by gently pressing into its surface a steel wedge. The surfaces of the crystals show natural etchings corresponding in symmetry with the hexagonal pyra- midal group. In general the apatite crystals of this phase resemble those from Natural Bridge and other localities in northern New York. The crystal faces do not admit of accurate measurements by reason of the rounded and uneven character of the surfaces. The forms m (1010), x (1011) and s (1121) were identified with a contact goniometer. Secondary apatite occurs in small bright crystals, perfectly transparent and light yellowish green to bluish green in color. The largest of these measured 6 mm in diameter. They show an ap- parent rounding at the termination which renders the determina- tion of the crystal habit a matter of some difficulty. Fair reflec- tions of the goniometer signal were obtained in all zones measured and the forms recorded were noted on all of the three crystals studied. The crystal habit as determined by the relative size of the reflecting surfaces is shown in figures 24a—24b. The following summary shows the results obtained from the measurement of three of the best developed of these crystals. SUMMARY OF OCCURRING FORMS, MEASURED AND CALCU- LATED ANGLES Form Angle Measured Calculated ane e} / ° / Cc Cool L010 :0001 gO 2%| go ° m IOI IOIO:0110 60 One GO fo) a 1120 IO10:1120 30 Gr zo fo) Y Io12 IOL0:1012 67 eel | O:7. I 3 IOI LOLO:IOLI 49 42 | 49 42 IOLO‘OITI Tit 84 | 71 8 re SEITE SEO) 37 43 | 37 44% y 2021 IO10:2021 30 Zon.30 31 WwW O73 1010 :7073 26 404| 26 48 z 3031 I010:3031 21 254-21 27 Ss II21 II20:1121 34 174| 34 14% £ IOLO:1121 44 183| 44 ny Me Sen IO10:2131 30 19%| 30 20 74 NEW YORK STATE MUSEUM GENERAL CONCLUSIONS The occurrence at Lyon Mountain of two distinct phases of a mineral species, as has been noted in the cases of quartz, calcite, the feldspars, amphibole and apatite, points unquestionably to two distinct periods of mineral deposition. Of these, the first may be said to be characterized by the production of large crystalliza- tions from an aqueo-igneous fusion, of which the superheated water acted as a powerful solvent. The marked prevalence of natural etched pits on the surface of the minerals of this phase, as well as their partial resolution bears evidence of the potency of this dissolving action. Considerable mechanical stress accom- panied the formation of the minerals of this period and the evidence is not lacking that the perfectly formed minerals were still in a soft or pasty condition when subjected to external pressure. The second stage of mineral production, which is marked by smaller and more perfectly crystallized individuals, was the result of recrystallization of the dissolved materials from the saturated aqueous solution, the dissolving action of which is apparent in the minerals of the first period. In some instances this second period may have been contemporary with the first, as in the case of the calcite of type I. In general, the minerals of secondary derivation are to be found incrusting those of the previous generation indicat- ing a complete change in the mode of production. EXPLANATION OF PLATES ta Pyrite from Lyon Mountain. Orthographic projection showing forms :/a (200), o (11), 6 (210), S) Ger) jand yer) tb Clinographic projection of same | 2a Quartz from Lyon Mountain. Orthographic projection showing forms: m (ro1o), r (torr), T(4o4r), 2 (ozz1), s (1121), x (st61) and q’ (10.1.11.1) 2b Clinographic projection of same 3a Hematite from Lyon Mountain. Orthographic projection show- ing forms: c (ooor),r (1011) and n (2243) 3b Clinographic projection of same 4a Calcite from Lyon Mountain, type I. Orthographic projection showing forms: M (4041) and p» (5491) 4b Clinographic projection of same ———SE——< ee Ll et 5a Calcite from Lyon Mountain, type I. Orthographic projection showing forms: M (4041), E (0.13.13.4) and mu (5491) 5b Clinographic projection of same 6a Calcite from Lyon Mountain, n, type II. Orthographic projection showing forms: Y (0.19.19.13) and q: (2461) 6b Clinographic projection of same showing parallel grooving caused by the vicinal development of the forms c (0001) and @ (o112) 7a Calcite from Lyon Mountain, type III representing the simplest expression of the pyramidal habit. Orthographic projection showing forms: I (2243), y (8.8.16.3) and Y (0.19.19.13) 7b Clinographic projection of same 8a Calcite from Lyon Mountain, type III. Orthographic projec- tion showing forms: IT (2243), y (8.8.16.3), 1 (0445) Y (0.19.19.13), V (2131) and (Ll: (14.12.26.5) 8b Clinographic projection of same ga Calcite from Lyon Mountain, type IV, rhombohedral habit _ with pyramidal modifications. Orthographic projection showing forms: T (2243), y (8.8.16.3), A (0443) and v (2131) : gb Clinographic projection of same . toa Calcite from Lyon Mountain, type IV. Clinographic projec- tion showing an element of the compound crystal figured in tob-10c. Forms: m (1123), I (2243), y (8.8.16. ae (0443), v (2131), » (5491), UW: (r4.22.26.5) and q: (2461) tob Calcite from Lyon Mountain, type IV. Orthographic projec- tion showing a compound cee consisting of the elements shown in 10a symmetrically disposed in parallel position on ~ a rhombohedron r (1011) of a previous generation toc Clinographic projection of same 11a Calcite from Lyon Mountain, type V. Orthographic projec- tion showing forms: I (2243), oC (4483), l (0445) A A (0443), jto22n); Ne (0772), S. (trata), 0 2131), R: Curse sige (2461) andc: (3471) t1b Clinographic projection of same Ol Plate 3 fi < \ =) a See ts Lew ce td . ‘ - qi 7 ee = 4 a : i oh an . —— \ 12 Calcite from Lyon Mountain. Stereographic projection show- ing distribution and zonal relations of the forms occurring on the five types 13a Albite from Lyon Mountain. Orthographic projection show- ing prevailing type of twin according to the albite law. Forms: 6 (oro), ¢ (oo), m (110), M (110), f (130), 'Z (130), x (ror), y (201), p (11) and o (111) 13b Clinographic projection of same 14a Albite from Lyon Mountain. Orthographic projection of cross penetration twins according to the albite law 14b Clinographic projection of same 15a Pyroxene from Lyon Mountain. Orthographic projection showing forms: a (100), 6 (010), ¢ (001), m (110), @ (O11) and 7 (211) 15b Clinographic projection of same 16 Development of planes in the prismatic zone of 15b showing shape and distribution of natural etch pits and their relatiom to adjacent edges Plate 5 tt ea Pavel Th ae Pm Wes “ 17a Amphibole from Lyon Mountain. Orthographic projection showing forms: b (o10), m (110), e (130), ¢ (101), b (101), r (o11),% (031) andgz (121) 17b Clinographic projection of same 18a Zircon from Parkhurst shaft, Lyon Mountain. Orthographic projection of type of larger crystals. Forms: m (110), a (100), p G11), v @2n) aud 7 4Ga0) 18b Clinographic projection of same tga Zircon from Parkhurst shaft, Lyon Mountain. Orthographic projection of type of smaller crystals. Forms: LG IO), a(100), p (rt) and Bigs) r9b Clinographic projection of same — 20a Epidote from Lyon Mountain. Orthographic projection on a plane parailel to b (o10), showing forms: a (t00), ¢ (oor), u (210), € (101), 7 (ror) and m (111) 20b Clinographic projection of same 21 Stilbite from Lyon Mountain. Clinographic projection show- ing parallel grouping. Forms: ¢ (oot), 6 (o10) and } (101) Zi 22a—22b Biotite from Lyon Mountain. Clinographic projections showing types of twins. Forms: c (001), b (o10) and p (rrr) 23a Titanite from Lyon Mountain. Orthographic projection showing forms: ¢ (oor), a (110), 6 (o10), m (110), n (75); n (221), # (111), and I (112) 23b Clinographic projection of same 23c Clinographic projection on a plane at right angles to that shown in 23b and showing a crystal of the same, habit twinned parallel to a i 24a Apatite from Lyon Mountain. Orthographic projection show- ing type of crystal of secondary derivation. Forms: ¢ (coor), m (1010), a (1120), Yr (1012), x (ror), y (2021), w (7073), 2 (3031), s (1121) and mw (2131) 24b Clinographic projection of same ‘ : Secondary quartz from Lyon Mountain showing occurrence of secondary hematite in shotlike hemispheres and pene disks. The scale is divided into centimeters. 8 98Id Md nis si Amphibole (hornblende) from Lyon Mountain showing dendritic deposit of stilbite on planes in the prismatic zone. The specimen is reproduced in natural size. Plate 9 3 =a Amphibole and quartz from Lyon Mountain showing transition stage from hornblende of the first generation to byssolite of the second and also the crust of secondary albite and stilbite on the primary minerals, The scale is divided into centimeters. Plate 10 Crystals of apatite of the first generation in pegmatite, from Lyon Mountain, showing a wedge of orthoclase driven into the side of the crystals by external force. The orthoclase fragment appears as a heart-shaped spot near the upper edge of the specimen. Note the bulging of the edge of the crystal around the fragment. The scale is divided into centimeters. Il 9}%Iq Oe sOME PEL MATOZOA FROMTHE CHAZY LIME- STONE OF NEW YORK BY GEORGE: HENRY HUDSON In some material from Valcour island, Lake Champlain, given by me to Mr Percy E. Raymond in 1902 he was so fortunate as. Poatid a ikacmenn of Eo laStidoctinws-carc hia‘riae- dens _ Bill. with two of the large deltoid interambulacral plates in position and showing much of the internal structure of an ambulacrum [pl. 5 fig. j]. In 1903, while examining some exca- vated material from the same locality (which the writer had left out to weather), Dr C. E. Beecher found a small fragment of a crushed individual which showed a pair of the plates I have called bibrachials, nearly in their proper relation to the great deltoids. In 1904 the writer found two bibrachials joined along Seucie eOmimon Siture, and these* dre fioured. on- plate 4 at L. While gathering up some of the remaining portions of the same weathered stratum in 1905, Erastus M. Hudson obtained the most complete specimen of this species yet found. From this material and from about a thousand separate plates kindly assembled for me by Miss Ada M. Carpenter from the unas- sorted collections of some years, and representing over 186 different individuals, as shown by that number of apical pieces, I have made the following more complete description of this. interesting species. Blastoidocrinus carchariaedens Billings Can. Ore. Rem, Decade 1V.18509. pz r8) pl: 1; fig. ra-1s Plates 1-7, text figures 1-3 General description. Theca large, in some specimens attaining a hight of 36 mm and a width of more than 40 mm, pentagonal, clearly separated into an oral and aboral surface with the greatest width at the boundary. Aboral portion of theca deeply invaginated, appearing in a side view as a low, inverted, truncate cone whose outer walls. 98 NEW YORK STATE MUSEUM make an angle of 58° with the vertical; the ratio of the length of these outer walls to the distance across the invaginated area in a specimen a little more than half grown is as II to 9, in older specimens the difference is greater. The oral portion, when the high ambulacral ridges and anal piece are in position, is four times as high as the aboral and rises from it as a dome, maintaining a vertical outline for nearly one third its hight. The published restorations of this species ee been made from fragments showing but very little of the aboral portion and with the ambulacral ridges and anal piece broken from the oral surface. These figures give the aboral portion nearly twice the hight of the oral while in reality the oral has very nearly four times the hight of the aboral. A side view of this species seems therefore to be more strongly suggestive of Pentremites than Mr Billings supposed. : The plates of the aboral surface, while nearly 80 in number, are arranged in four horizontal circlets. The first two are of basals and radials as in crinoids. The plates of the third circlet consist of 10 bibrachials and 13 interbrachials. The plates of the fourth circlet are between 50 and 60 in number but while the alinement is horizontal and not zigzag, the circlet is cut at each radius by the upward extension of the bibrachials. The radials are so remarkably like the basals of certain Rhodo- crinidae and are so abundant in Chazy deposits that it has seemed best to describe them rather more fully than is usual. Basals. Basals unknown but probably very small and together having but little greater area than a joint of the stem. The “basals” of E. Billings, of which he says “from another speci- men it appears that there are at least three, if not four or five, basal plates, and their form is remarkable,” are not basals but radials. All published statements concerning the basals have been made on the authority of the quoted passage and are without value. Radials. Radials five, many angled; each having two (?) proximal very short sides resting against the basals; two long sides where each plate meets its neighbor in this circlet; next above this on the left is a side which supports the largest plate of a lower row of two or three interbrachials; on the right are either two or three sides meeting the whole lower row of inter- brachials; the remaining two sides, which are distal, support the bibrachials. ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK 99 Central plate Wing plales ad Fig.z Analysis of the theca of Blastoidocrinus carchariaedens. The bra- chioles have been drawn for one side of one of the deltoids and all their external ossicles out- lined save a portion of those between the rst and the roth and the tips of the 11th to the r8th. The 6th external ossicles have been shaded as have also the roth, r4th and 22d ossicles of the uniserial brachioles. At az the lower ossicles of the 7th brachiole have been drawn to a larger scale. The wing plates of but two of the radii are shown. ‘The piece marked ‘‘central plate’”’ is the apical piece. IOO NEW YORK STATE MUSEUM. The radials are thus seen to be unsymmetrical, supporting one or two more plates on their right sides than on their left. This has turned the apex of each plate to the left and through the bibrachials has moved the distal or outer end of each ambula- crum from 7 to 10 degrees from its expected position, as is shown in plate 1, lower figure. The center of this figure was found by extending inwardly the lines marking the suture between each pair of radials. ‘The position of these lines extended outwardly is marked on the circle nearly surrounding the figure. The proximal portions of the radials are gradually bent upward - [pl. 4. k] to form an angle of 90 degrees with a line across the base of the theca. They thus together form a deep conical pit or crater whose outer rim is a little more than twice the diameter of the stem but which gradually becomes narrower as it pene- trates the theca and brings the thin, inner portions of the plates against the stem at a depth of seven or more of the stem rings. The outer or distal portion of the radials is bent upward at an angle of 30 degrees with the line across the edge of the crater and this portion of the plate (one third or less of its length) is from 1 to 2 mm in thickness at the suture or from three to six times the thickness of the edge next the basals. An excep- tion to this thickness is made where the radial meets the smallest interbrachial plate of the lower row; here the thickness at the edge is markedly reduced, as shown in plate 4 at 1. Each plate shows a raised central mound on the rim of the crater, carrying this rim outward a little and giving it a some- what pentagonal figure. From this mound, or just above it, there radiate some Io or 20 depressed grooves, the more nearly transverse ones being the deeper and together making a marked transverse depression a little below the apex of each plate. The more marked of these lines run across the suture and either across or between the lower line of interradials. The portion of the plate forming the inside of the crater is ornamented by some fine rounded labyrinthine ridges as in plate 4, g, or a dew- drop pattern as at h. ‘he inside suriace of -these plates is smooth with sometimes a raised central, longitudinal ridge at the bend; probably representing attachment of viscera [pl. 4, 1 and j]. The largest radial so far found measures 10.48 mm across at greatest diameter or very nearly twice the diameter of the radials of the specimen figured in plates 1, 2 and 3. This plate [pl. 4, a] shows less ornamentation than the others but the radials seem to vary rather markedly in this respect. Fig- ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK IOTL ure c on the same plate shows rather clearly a series of growth lines, or rather rest lines, where periodic pauses seem to have been made in addition to the edge of the plate. The resemblance of these plates to the basals of certain Rho- docrinidae (especially to those genera with concave bases and two or more interradial plates over the no longer truncate upper . edge of the radial) lies in their approximate size, the bent con- dition, the thinner proximal portion, the radiating ridges on the distal surface, the depressed apex, the occasional visceral ridge [see text fig. 8] and the more than usual number of angles. In the Rhodocrinidae, however, the distal ornamented area is usually much greater than the bent proximal area. ‘The plates once recog- zed are easily separated from all others. Bibrachials. In each radius of the third circlet is a pair of usually hexagonal plates each about one and one third times as long as the greater width of the radials and a little less than half as wide.as they are long. The bibrachials meet over the apex of a radial in one long, straight suture and their narrow (sometimes rather pointed) distal ends reach the boundary of the oral surface and together support the end plates of an ambu- lacrum and usually four very short brachioles. The outer edge of each plate has three sides; the two lower meet the end plates of the two rows of interbrachials and the remaining side meets the horizontal outer third of the base of one of the great deltoids and thus also reaches the oral boundary. | The outside of the plate is ornamented with transverse, fold- like, rather rough ridges which become less prominent and dis- . appear as they reach the long common suture of the two plates. The inside surface is smooth. The face of the common suture is very smooth and near the middle of the plate this suture occupies half its width, the plates together making a very strong ~element of the theca. The outer suture is crossed by numerous grooves which, at least on the upper half, mark the position of the pores or slits on the deltoid through which water passes from the hydrospires to the exterior. These features may be seen in figures 1, m and n, on plate 4. The number of external, trans- verse ridges and the number of grooves across the outer suture will depend on the age of the plate as we shall see under the description of the deltoids. 3 These plates have been called bibrachials without any inten- tion of signifying that they are homologous with the brachials of crinoids. They support the distal, not the proximal end of 102 NEW YORK STATE MUSEUM an arm. ‘The first and second circlet of similar forms have however received crinoid terminology and I have used similar terms for the plates of the third and fourth circlets. These last circlets lie in the brachial region of crinoids. The bibrachials here follow the radial as if that were a primaxil and the pair suggest the II Br, of crinoids with their long axes placed verti- cally instead of horizontally. I do not mean to lead the reader to conclude that I have considered these plates as divided radials though a comparison with the higher blastids might hastily lead one to that conclusion. Three other hypotheses suggest themselves which may be here given without comment. These plates may be homologous with the cystidean pair of plates that would very naturally le over what became a radial (through reduction of number and acquisition of pentamerous symmetry), possess a vertical common suture and become modified on being reached by the extending oral food grooves. That is, these plates may be considered strictly interradial and without radial elements between them. In this case they are but specialized plates similar in origin to the other plates of the third circlet. The double character of these plates and their position at the end of a long double row of highly specialized adambulacrals | might lead us to adopt the hypothesis that they were derived from the outermost adambulacrals of such a form as Protero- blastus on which a more distinct differentiation into oral and aboral surfaces had been impressed together with loss of func- tion at the aboral end of the arm. A third hypothesis, and one perhaps more suggestive than the last, would be to look on these bibrachials as true interambulacrals thrust from the oral sur- face and to their present radial position by the great develop- ment of the deltoids but still bearing brachioles and outward markings indicating a former respiratory function. Interbrachials. In each interradius there are two or three interbrachials of the third circlet, one much larger than the other, and from 10 to 12 smaller plates of the fourth circlet. The upper ends of the latter are each in contact with the middle part of the great deltoid above. They no doubt once functioned as respira- tory plates and to a certain extent they may still do so though any such present function is unknown. The arrangement, shape and relative size of these plates is shown in figure I of the text as is also their contact with the bibrachials and radials. Plates 2 and 3 show four different groups of these interbrachial plates ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK 103 in position. These plates complete the aboral surface of the theca. Deltoids. Perhaps the most remarkable structures of the oral surface are the great deltoids—large triangular plates, each of which has come to occupy an entire interambulacral area. The superficial resemblance of these plates to “sharks’ teeth” evi- dently suggested the specific name, and such plates have induced local collectors to stoutly maintain that “big fish” existed in Chazy. time. These interambulacral plates have the middle basal portion strongly bent inward and the lateral portions rather markedly outward; a vertical section of one such plate would thus be con- vex outwardly and a transverse section concave outwardly. The two upper or lateral sides of each plate support on each edge from 6 (or less) to 40-(or more) brachioles with their cor- responding adambulacral or flooring plates. Each bordering brachiole (with the possible exception of one of the apical pair) is connected, by a pore or slit between the adambulacrals, with a vertical or rather a longitudinal groove Gn ie miner Surface ofthe deltoid. From both sides-of this groove there extends a remarkably thin respiratory sheet, slightly bent away from its fellow soon after its origin and usually still more so near its inner margin where the edges - meet in a rounded roof and form a lamellar cavity through which was maintained a ilow of sea water which made its exit at a short slit at the base of the deltoid. This row of basal slits, One togscach! hydrespire, is very clearly shown in plate 5 at]. This figure is reduced from a photographic enlargement and as the slits did not appear as dark as in the specimen, the seven outer ones were darkened with india ink; the remaining-slits have been reproduced without retouching of any kind. The bibrachial shown in the figure had been moved slightly inward from its natural position and the specimen thus shows the water exits to better advantage. .The arrangement of these hydro- Spices on the plate may be seen in figure 2 which is froma camera lucida drawing of a cross-section of the right postero- lateral interradial deltoid made at, or just below the 17th brach- iole and which shows 34 hydrospires. The most rapid increase of growth of the deltoid was at the two lower angles where new brachioles were regularly added at the side of and just below the last formed, until the number became perhaps as many as 50 on a side, giving a probable total 104 NEW YORK STATE MUSEUM of 500 brachioles to some old specimens. With each added brachiole there was also added a very short, rudimentary hydro- Spire consisting at first of a membranous fold open externally. As the hydrospires with their grooves are no farther apart in adult specimens than in young ones [see pl. 5 fig. k-o of inner surface of deltoids, where approximately 14 grooves lie side by side in a width of 5 mm whether young or old plates are taken] it follows that direct lateral growth was limited to the widening of the plate by the addition of these new brachioles and their hydrospires. | Direct upward extension of the hydrospire and the portion of the plate bearing it would soon bring the base of any one brachiole up to the level of the former position of its next older companion while the companion constantly maintained its former superior relation by a similar upward extension of its own hydrospire and plate portion. Thus the plate was indirectly widened by upward growth of the portions consecutively added at the lower angles. This upward extension in the early stages of the development of the plate was no doubt as rapid as the extension of the lower angles, but at a later stage the lower angle extension was the more rapid. The rather remarkable: parallelism of the hydrospires would show that the basal plates of a young brachiole ceased to grow as soon as a subsequent brachiole was added. That there was a slight enlargement of the later formed brachioles is however shown in plate 5, figure o, where the grooves of the hydrospire, between 30 and 39, begin to show a very appreciable change in direction. Another fragment not figured shows a still greater extension of this angle of a plate and a change in the direction of the grooves of more than 45 degrees. It is on this bit of evi- dence that I have suggested that the 39 side grooves of plate 5, figure 0, may have been surpassed in this specimen by at least I1 others. Its possessor must have shown a more remarkably starfishlike form, when viewed axially than the specimen figured in plate 1. It must also have brought the ends of its ambulacra more nearly down to a level with its base. The hydrospires and their plate portions were also extended downward and the points of their origin became thus left along a line still visible on the external surface of the plate and con- necting the older central portion with the newer extension of the angles. This line may be seen in plates 1, 2 and 3, and is also clearly shown in plate 5, figure j. This downward exten- 5 IO K OR ‘ouTySoyUL poly Ajjeysed e syussoider Ajqeqoid Jou109 puvy-}ystr 1oddn oy} Ieau somdsoipAy 10410YS ayy JSULYSE SUIYSOI [vIIO}eUI sTYyZ JO yIsodep AAvoyoyy, “yrsodap Ayz1va YSTMoT[eA 9Yyy JO pOT S}I JO UL Surjyey oy} AQ popeorpUL Sv ospo IOUUT S}t JSOT OsTe sey aitdsoIpAY YASI sy, ‘“sertdsorpAy jo sospa rauUt poyoryop of yuTod smorre nO ‘spisodap shosovuodreo sopyeotpur surddiqs Jouy oy} ‘Ae{O IO puvs YSIMOTIEA oUYy AOA v JO SyIsodap [eULayUT Jo UOT}IsOd 944 SozZVoTpuT SuTYyoyeY ssoroO ey “FYst] YONUE poz}zTUisuvsy UOT}OOS JY} 9LoYM Sve pepeYysUuN PuUNnOLINs puv popeYs o1v sjUSUala [eIOv[NquIe ayy, “£ oyetd UT po}eorput st UOCT}OOS ey} jo uoyyisod oy, ‘SUA PIVIIVYOIVS “g jo vIOR[INqUIe OM} PUP PlO}[ep & YSNOIY} UOTJOoS OSJOASUEI] BJO SUIMPIP BPTON] vrouleg % “By NEW Y TONE OF M CHAZY LIMES FRO TOZOA ON SOME PELMA Wa . vaspe}4}) 4) (thi cag Rn ory ig ys Ne a be / / ‘ ly a een ey ! ~ Se a ee ~~ ee _~ = —— se ae De ere aA ay Wo ay \ k \ ah} sb ‘ anh a \ \ oN 4 VA \ ae AX \ : \ » At 1) W\ ete 106 NEW YORK “STATE MUSEUM _sion of the plate was not so rapid as its upward. It required also the gradual filling in of the older position of the hydrospire slit or pore. The filled in material did not reach the outer sur- face of the plate and the external furrows thus lie directly over the internal grooves. That the filled in portion was the weaker and more readily dissolved in weathering seems to be shown by the widening of the slits of the lower margin in all plates found in a detached condition. This widening is shown in the figures of plate 5 save in the fragment protected by its bibrachial at j. During the downward extension of the older hydrospires there appears to have been a widening of their bases to correspond with an increase of function. This was accompanied not only by the inward bending of the plate toward the center of the theca, of which it may have been in part the cause, but also by the throwing of the outer ridges between the slits into a marked zigzag and giving them a still stronger external thickening near the suture. There was no marked thickening of the plate after the addi- tion of new sheets of stereom at the edges. Young plates are somewhat thinner than the old plates but the latter are thinner near their centers. The structure of the ambulacrum, having at least in places, four plates in a line across the edge of the deltoid, necessitated a rather thick sutural face for even young plates. This thickness was gradually increased at the lateral edges of the plate as is shown by figure 2. The increased growth at both ends of the hydrospires and the thickening of the plate was accompanied by increased growth in depth of the hydrospire membrane; the oldest portions or that under its place of origin becoming the deepest, hanging far into the coelomic cavity, and giving a triangular outline to the structure when viewed from the side. To enable them to make this continued growth these structures must have had their inner edges remain membranous. No primary calcification is apparent in the cross-section, their outlines being seen only as a fine, rather interrupted line of carbon particles. The portions of the membrane next the plate became strengthened by the deposit of calcareous matter, but the whole structure was so delicate as to be rarely preserved. Plate 5, figure n, has a small area showing the outer edges of these thin hydrospires still attached to the plate. Another fragment of a deltoid shows them in a still more perfect state of preservation but so filled in with rock deposit as to show but little in a photographic ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK 107 enlargement and it is therefore not figured. Under the micro- scope the specimen shows the walls of the hydrospires to consist of irregularly thickened and corrugated sheets so constructed as to give strength with use of very little material and so secure the thinness necessary for the exchange of gases with the sea water. The slight bending of the inner ends of the older hydro- spires in figure 2, the loss of the inner edges of several of the larger and the detached and shifted edges of others, indicated by arrows, all point to their membranous character and their tearing during decay. The addition of brachioles and hydrospires while consecutive was broken by periods of rest, and “ growth lines” so formed may clearly be seen in plate 5, figures h and i, the older deltoids being easily recognized within their newer margins. The younger, thinner deltoids show vertical grooves on their upper surfaces which lie over the hydrospire grooves below. The thicker additions made to the edge of the plate by the upward growth of the newer brachioles soon mask their external parallelism and give rise to a series of external ridges running at right angles from the lateral plate margins. It would seem that young plates having but 12 hydrospires could hardly have had any portion of their bases supported by the bibrachials. The interbrachial plates alone would support the lower edge of the deltoid and the form viewed axially would be simply pentagonal, without the asteroidlike projections, or as in Troostocrinus. The increase in width of the deltoid would be accompanied by imeneasesin lencth or the. bibrachials. «Their pecultar form «is thus in part brought about by the greater growth at their distal ends. It may be noted that this extension has constantly carried the distal end of an ambulacrum farther away from its radial plate. Earlier stages in development would show that closer proximity possessed by its ancestral forms and from which the Eublastoidea with their notched radials took a diver- gent line. A comparison with Codaster leads one to the conclusion that the deltoids, in their origin, were true deltoids or orals. I may have asserted rather too positively that the hydrospires _ lie in the grooves on the inside of the plate. In the cross-section of the deltoid the boundary between the coelomic cavities and the plate could not be readily made out. The outer ends of the hvdrospires are clearly marked by carbonized lines convex out- 108 NEW YORK STATE MUSEUM wardly. These are without doubt very near the inner boundary of the plate. There exist in this cross-section more faint and diffuse lines of scattered carbon particles that connect these outer ends of the hydrospires with each other and where the lines can be distinguished they seem to lie on the whole a little nearer the exterior of the plate. This gives one the impression that the hydrospires rested on the internal ridges rather than in the grooves. The fact that the basal hydrospire slits open directly into the grooves seemed to me to negative such a con- clusion. The weaker carbonized lines probably do not mark the inner boundary of the plate but show the outer folds of the membrane forming the hydrospires. Jf we imagine a series of folds formed as in figure 3 of the text with their outer edges Blastoidocyinus Eb Hedson Fig. ; A diagram of the hydrospires of Codaster copied from F. A. Bather’s The Echino- derma [part HI of A Treatise on Zoology edited by E. Ray Lancaster] p. 83, and a hypo- thetical diagram to show probable manner of formation of the hydrospires in Blastoidocrinus. thrown very closely together and adhering in part before stereom formation took place and if we further suppose that stereom was formed more abundantly at the outer folds as in Troostocrinus and Codaster, while at the same time the outside was covered by the thick stereom built above the fold along that wide face of the deltoid supporting the four rows of plates before men- tioned; then we shall find a condition of things not only as shown in figure 3 but also actually existing in figures k, 1, m, n and o of plate 5 where the ridges are seen to be narrower across their upper edges than the distance across the groove at the same level. ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK I09Q The inner surface of a deltoid is not often seen in as perfect state of preservation as in the material photographed for these. plates. The dark calcite, showing the presence of carbon, does not seem to weather so rapidly as pure calcite. This differen- tial weathering has often left the plates in great perfection. The extra deposit of carbon then at the outer closed edge of the hydrospire fold should tend to preserve it, while the less car- bonized filled in ridges between the hydrospire folds and repre- senting the inward thickening of the outer fold would be more rapidly dissolved away and thus leave the more uniform smoother condition usually found. If this idea of the plate extension be correct the stereom of the plate can hardly be said to be folded. The advantage of closing the outer slit of the fold save at its extreme ends will be manifest and the flow secured by connec- tion with the food groove of a brachiole gives us a very effective organ of respiration. Reduced to their lowest terms these hydrospires seem to be diplopores added to a plate through an inward fold of ectoderm and coelomic epithelium at a suture and bridged over across the outer middle of the opening to form a sac with two external openings or pores. In true diplopores there was no extension of the sac and the openings soon became included by the continued growth of the plate around them. In pectinirhombs the fold crossed the suture, a probable extension of the membranes occurred and therefore. a separation of the pores through plate growth, the extending lines still indicated at the surface as in Pleurocystis, or obliterated as in Schizocystis. Hydropores of the form of Blastoidocrinus seem to ke derived from the diplopore type from plates supporting brachioles and thus coming to be associated with the power to maintain a marked flow of water, in which case the neglect to follow the established and inherited rule to close the plate around the pore would be a “ weakness ” tending to insure survival and the pores would thus come to lie at opposite margins of the plate. Brachioles. The brachioles start out at nearly right angles to the edge of the deltoid but at the sixth external plate [the first row shaded or darkened in fig. 1] the brachiole assumes a nearly vertical position. ‘The brachioles at the apex are the oldest on the deltoid and are also the longest, being 6 mm long in the specimen figured, and thus as long as one fourth of the extreme hight of the specimen. These oldest brachioles and some six to eight others on each side of them show on their outer sur- faces two rows of alternating plates some 60 in number. TO NEW YORK STATE MUSEUM Farther out on the ambulacrum the brachioles possess this outer biserial arrangement between the first and the eighth but after this are uniserial. The larger drawing of the seventh brachiole at a in figure I shows a transitional form. ‘These newer brachi- oles show from 17 to 30 external plates. Each brachiole, with the exception of the two oldest, starts with a single large kidney- shaped plate very slightly less than .5 mm in longest diameter. This is surmounted by two plates in which the lower or distal. is much the smaller; the next two plates above this are of nearly equal size and of the pair that follows these it is the upper or the one: nearest ‘the axis. of, the theta that 4s tae smallici ait appears as if the outer smaller plate of the first pair became the foundation plate of the arm. ‘The law of biogenesis would indi- cate that biserial brachioles preceded the uniserial but the change in this instance may be caused by a rotation of the brachiole to the left on its own longitudinal axis, as is indicated at A7 figure 1 and by other earlier brachioles of this specimen, bringing the left-hand plates of a biserial arm to the front and making the arm appear uniserial. The diagonal sections of the lower brachioles in figure 2 show in places a section through a pair of plates and the structure near the base of the brachioles sug- gests the arrangement of the side plates and outer side plates of Codaster. Where the upper brachioles have been turned away from the wing plates, as shown in plate 3, lower figure, at a, the older brachioles seem to have had an additional row of plates on either side and alternating with the outer or back plates. A cross- section of one of these brachials would give the form of a paral- lelogram with its long axis set at right angles to the surface of the wing plate. The middle two fourths of the rear wall consist of a double row of very small, alternating, covering pieces. The cross-section of the lower parts of the newer brachioles seems to show only the back or outer plates (the end of but one of them seen from the outside) with greatly elongated sides and with traces here and there of what may be small covering plates. One brachiole in the anal interradius seems to have been certainly free from the others for its entire length but the brachioles with apparently uniserial back plates have their margins zigzagged as if they had become bound, each to its neighbor, at their sides. This may not have been true of all the upper brachioles but where some of the older ones have fallen away from the wing plate, as in plate 3, lower figure; ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK III the evidence seems to favor the idea that these brachioles swung out as one continuous sheet and that the outer edge of this sheet was subsequently broken away. This feature reminds one of the arm of Cleiocrinus, a species of which I have found in the same bed with Blastoidocrinus, and is another good example of homoplasy. How much of the base of this sheet could leave the internal plates of an ambulacrum is another question. It seems to have been fixed at least up so far as the eighth row of back plates. There remain for description some brachioles apparently ion in number,atvached not to the deltoid but to the upper ends of each pair of bibrachials. These appear to be biserial, and are so at least in part, but they are small and tapering and the arrangement of these plates is made out with exceeding difficulty. The inner two are still more tapering and rudi- mentary in character. They also possess no perfected hydro- ‘spires for the bibrachials are destitute of any such structure. Are these old brachioles remaining attached to a plate that once possessed a hydrospire system or are they new brachioles in the building? If old, then the new brachioles must be formed between the more mature outer ones and the last brachiole on the deltoid; if new, they must be constantly pushed to the side by still newer additions and one by one take their places on the deltoid. There is no evidence to show brachiole formation between these and the deltoid but these grade very regularly into the more mature forms and there are a number of brachioles. with their basal single plates still half on the bibrachial and half on the deltoid. The fact, already mentioned, that these lowest plates make practically no increase in size after being given a position on the deltoid, is of itself significant in this connection. . Adambulacrals. Between. the deltoids the coelomic cavity is completely. roofed over by an arched wall, concave inwardly, consisting of a double row of alternating (?) adambulacrals. These plates, seen from the side, are somewhat in the form of a parallelogram with the longitudinal axis about twice as long as the transverse axis. The two long sides are slightly but very regularly convex toward each other; each of the two ends bears four obtuse angles. The middle face of the outer end rests against the inner edge of a deltoid; the face below this sinks into the coelomic cavity and is parallel to the short side of the brachial end of a hydrospire; the outer face of the same Ii2 NEW YORK STATE MUSEUM end rests against one or more small plates apparently forming a double row down the middle of the edge of the deltoid and just inside of the apparently single kidney-shaped foundation plates of the brachioles. These small plates, with probably some others, serve to floor a rather large brachiolar cavity which is represented in figure 2 by shading its boundaries. The sec- tion, which is rather thick, admits much light over this area and thus suggests a series of connected brood chambers. The boundary plates of this cavity require further study. The inner end of an adambulacrum has one face against a covering plate, a middle concave portion bounding nearly a fourth of a-circular food groove, and an inner or lower face that abuts against the opposite row of adambulacrals. Between each plate and its neighbor in the same row there are two openings, one into the food groove along the line of juncture of the upper, inner faces of the plates and one into a hydrospire along the line of juncture at their outer or deltoid edges. The plate is grooved from the middle of the longer concave upper surface toward the food pore on one side and again from the same middle portion toward the hydropore (?) - on the other side. This gives the appearance of a little twist to this outer long edge of the plate and shows that the brachiolar chambers along the side of an ambulacrum were probably con- nected with each other. The older plates retained the power of extension of their stereom and the upper figure of plate 1 will show that the older became the larger and very materially wid- ened the ambulacrum. These plates rather strongly suggest the ambulacral plates of Asterias. There is no trace of a lancet plate and perhaps the question of homogenesis of bibrachials and lancet plates 1s worth con- sidering. Our species has little to offer, but its bibrachials partly separate the deltoids and reach the primary meristem of a ray at one end, while the other abuts against the apex of a radial. This is closely the position of the lancet plate in Codaster. The lancet plate of Eleutherocrinus with its seem- ingly double oral ends would suggest that possibly the primitive lancet plate was double. Covering plates. The covering plates of an ambulacrum are remarkably large and heavy. Each is as wide as the adambula- cral directly over which it rests and its thickness is extraordinary. The outer or side surfaces of a row are slightly concave and very smooth; against these surfaces rests a portion of the brachioles. ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK I1I3 The upper surfaces of some of these plates may be seen in plate I, upper figure, and an impression of these surfaces in plate 6, figures k and 1. Wing plates. Along the center of each ambulacrum and between the upper portions of the two rows of brachioles but rising a little above their closed tips, there is a linear series of three somewhat razor-shaped plates with their broad and slightly concave backs uppermost. I have called these wing plates and have outlined the exposed surface of two rows of them in fig- titen) <0 whe texts) im plate -6 atja,-b,.c and d, are different views of four first wing plates; b and c show outer surfaces [the proximal end of c is probably the lower end of the figure]. These plates lie nearest the anal piece and are the shortest. At e, f, g and h, are different views of four second wing plates. At i, j and k are different views of some third wing plates; k shows the impression of the tops of the covering plates which are more clearly shown at 1, which is an outline drawing of the same face of the specimen. These last become longer than the second plates and usually terminate the row. In the specimen figured on plates 1, 2 and 3, the knife-bladelike points of these curve down to and touch the smallest end brachioles of the ambulacrum. Figures b, f and j show surface ornamentation due to addi- tions through growth. The first wing plate, b, was the first of its series formed and additions were made principally at its sides, its base, and its distal end. The original small second wing plate may still be clearly seen as the innermost V in fig- ure f, and six additional periods of growth have left the arms for six additional V’s or rounded ridges. This plate seems to have attained its full length at the end of the third of these seasons and thereafter only increased its hight and width. Fig- ure j shows the same process of extension of the third wing plate and older specimens may have added a small fourth. Fig- ure k seems to be a third wing plate that did not terminate the row. The hollow or grooved upper surface, shown clearly at d, was produced by an upward extension of the edges of the plates to keep just in advance of the extending tips of the brachioles. Figures c and g¢ show a labyrinthine surface ornamentation mich like that found on the proximal third of some radials. Traces of the same may be seen at b. Inc the growth lines are very nearly obliterated, in g one does not detect them. II4 NEW YORK STATE MUSEUM Water vascular system. Frequent reference to the respiratory system has been made during the description of some of the more prominent structures involved. There remain however some points which seem to be worthy of further notice and which are now presented. The 17th hydrospire of figure 2 extends into the coelomic cavity more than six times as far as the second; it is also more than 12 times as long as the function- ing new ones. Its area presented for osmosis is therefore at least 36 times as great as that of the smaller ones. This would mean that in order to serve the function of respiration as well as the younger hydrospires, the flow of water would have to be 36 times as great. A large sheet charged with carbon dioxid -and with the loss of nearly all its dissolved oxygen would be valueless to the organism, yet the continued growth of these old hydrospires would emphatically indicate increase of function. That there was an increase of function is also shown by the deposit of exceedingly fine sand or clay colored by limonite which we find to be greatest along the inner edges of the largest hydrospires and which is represented by cross hatching in fig- ure 2. This deposit seems to have been swept in just before death and after the falling of the theca to the sea floor. . The flow of water was down the brachioles into the brachiolar chambers, which also show the presence of the same yellow deposit on their walls, and from here to a small extent through the openings to the food grooves and so on through the enteric cavities; but to a very much greater extent (and freed of its food content) through the pores opening into the hydrospires and out at the base of the deltoid. I have before referred to the evidence of greater functional activity at the middle of the base of the deltoids, and the upper row of interbrachials may also be associated with this function. In fact the appearance of this upper row is remarkably suggestive of gradual increase in number at their ends. Whether the hydrospires pass under this row or not is as yet unknown. The comparatively slight difference between the older and the newer brachioles and the very probable great difference of water flow in the corresponding hydrospires are suggestive of open- ings connecting each brachiolar chamber with the others of the same row (of which we have already had evidence) and of a marked flow of water through them toward the peristome but remaining outside of the probable covering plates of that area. This arrangement would secure the required greater flow for ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK IT5 the older hydrospires and the marked widening of the ambula- crum toward the same area in this species (and in Asteroblastus and related forms) is to me indicative not alone of the required slight increase of size of the food groove but also of the increase of the functions of respiration and reproduction. At certain points in grinding down the section shown in fig- ure 2 there was visible a small rather square figure outlined by carbon particles and lying directly under the inner ends of the adambulacrals. This suggests a radial water canal which may have been connected with the hydrospires through side branches. If this additional structure existed the similarity between this ambulacrum and that of an asteroid would be extraordinary, the hydrospires being comparable to ampullae and the lining of the brachiolar cavities to podia. Anal piece. The wing plates radiate from a high central star- shaped plate apparently formed from five consolidated orals or from five upper or orad portions of the deltoids as shown in figures of Asteroblastus where the food grooves are made to pass over the outer edges of a starlike central portion which resembles in a very remarkable manner the central piece of Blastoidocrinus. In the latter species however the food grooves lie on a horizon but little above the bases of the brachioles ena: 2 depth: below. thiseapical piece. equal to the-sum. of the extreme depth of a wing plate and the hight of the massive covering plates. A reference to plate 2 will show how far down this must be. The apical piece stands in the same relation to the covering plates of the peristome as the wing plates do to the covering pieces of the food groove. There is plenty of room under this piece for a series of covering plates as in Nucleocrinus but with the anus thrust through them and by a bend above them opening laterally at a surface flush with the grooved side of the plate and just back of the peculiar brachiole of the anal interradius. Thus the apical piece might better be considered as formed of fused anals than of fused orals. We may note that it is possible that the anus had no external opening. If echinodermal respiration may be in part effected by water enter- ing the alimentary canal by either mouth or anus (as in the “respiratory trees” of holothurians, the “accessory intestine ” of echinoids and the “ ventral sac ” of crinoids) we may possibly have here a somewhat similar condition of things in which there is a flow from the rectum over the covering plates of the peri- stome and swept away through the older and larger hydrospires. 116 NEW YORK STATE MUSEUM A series of sections or the gradual grinding down of the oral portion of the specimen figured in plates 1, 2 and 3 would no doubt. throw much lhght on this subject but it seems better to await the finding of other fragments rather than to further muti- late so perfect and unique a specimen. . Views of these fused anal plates may be seen in plate 7. Fig- ures a to o represent the under surfaces of a series arranged according to probable age, an ontogenic series. The piece is at first rather thin, its vertical axis less than half of its horizontal and showing no sign whatever of a central perforation. The piece at a is tilted a little to show its thinness. Figures b, c, d, e and g show the beginnings of an indentation which becomes very marked as the piece increases in age. The more mature pieces 1 and o show also other indentations. The piece has grown principally by additions to its under surface and to a less extent to its edges. The deeper indentation is rather suggestive of a bend of the rectum, the anal interradius being perhaps the lower in the figure. The interradial indentations in figure o may be the impressions of plates covering the peristome. Figures , g and x are of upper surfaces showing the grooving caused by increased upward growth due to more extended additions to the plate edges as in the wing plates. Figure g is the anal piece of a regularly four rayed or tetramerous specimens while figure x is of a specimen having its anal piece of six fused plates and possessing a small sixth ray. The vertical axis of these pieces is increased in some specimens to nearly three times their horizontal diameters. Stem. Billings described the stem as “round with an alimen- tary canal so small that often the detached joints seem to have no central periorations. = = the dlatetaces (oim pie tseparate joints exhibit strong radiating striae.’ The diameter of the stem of the specimen shown in plate I is 3 mm while the joints themselves have a thickness of about 1.4 mm as may be seen in plate 3, upper figure. The last joint left on the stem fragment of this specimen seems to be split across in a direction nearly parallel with the plate face and while it shows a central perforation about - .3 mm across, or one tenth of that of the stem diameter, it does not show the strong radiating lines mentioned by Billings. Associated with the fragments of this species, however, are stem joints and roots shown in plate 7, figures r to w, which do show these lines. These stem joints are not abundant here and this would indicate a short stem. I have found no evidence as yet that the stem pene- ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK II17 trated the theca to the depth figured by Billings and so deep a pene- tration in his specimen may have been the result of partial crushing or deformation due to pressure. Taxonomic position. Before attempting to discuss the position of this curious species with its approximately 50,000 plates and ossicles it may be well to point out that the close to go plates of its aboral surface do not necessarily point to a generalized type of low rank. A period of stress developed the many centers of stereom forma- tion and the numerous and irregular plates of a form like Eocystis, but protection in this direction once secured in its adjustment to its environment, there could occur the passive loss, through the mechanism of inheritance, of a plate or so at a time and the others would simply extend their surfaces a little more to keep up a com- pact exterior. New crossings would tend to replace loss, but a Mendelian factor has entered that tends to simplicity and though loss be slow-it is nevertheless sure until it begins to interfere with some other function. Thus the few thecal plates of a Cryptocrinus are indicative of a higher genetic position. A period of stress for some other function would require response or extinction and again lead to proliferation of parts as in stem or brachiole development. The law briefly expressed is that the quiet of an unexacting environ- ment for any part leads to numerical or other simplicity of that part, and that the stress of an exacting environment, on still plastic parts, leads to gain in numerical or other complexity of that part. Our form seems to have been living in a period of stress in rela- tion to respiration and reproduction. We therefore find five points of what we may call primary meristem, developing adambulacrals, covering plates, wing plates, brachioles, plates lining brachiolar chambers, and hydrospires; and exciting the neighboring deltoids and bibrachials to constantly add to their area. This increase of area to the strong bibrachials would tend to lift the oral surface away from the interbrachials. These interbrachials are away from the points of activity and any extra activity on their part might lead to serious interference with the larger water exits of the deltoids. Release of pressure would render the water outflow the easier and in the membranous margins of the extending ends of the hydro- spires new centers of stereom formation would naturally arise and fill in a series of plates representative of the external stereom thick- ening of the hydrospire folds of Codaster. The result would be a partial fourth circlet of supplementary plates, either homolo- gous in part with the stereom formation of the inner surface of the 118 NEW YORK STATE MUSEUM deltoid [as in fig. 3] or from new centers of stereom formation and therefore homologous with no plates whatever. It is very highly probable that these plates of the fourth circlet are associated with respiration and that there is a regular increase in their number, newer plates being formed at both ends of the row until as many as 20 were formed in each interradius. The remaining plates of the aboral surface and the five single interambulacrals of the oral surface are really indicative of a rather highly specialized type. The anal piece, the wing plates, and the brachioles of our genus might perhaps cover an oral surface much like that presented by Asteroblastus and its large number of thecal plates and very remark- able apical piece are suggestive of relationship. Our genus how- ever possesses no diplopores and the remarkable differentiation of the plates of the aboral surface and the unique system of hydrospires clearly separate it from the Protoblastoidea of Bather (1899). The resemblance of the central plates of the oral surface of one to those of the other, seems to be but another example of homoplasy. While the deltoids of Codaster offer some remarkable resem- blances to the genus under discussion, we may note that our form still has more than “the normal definite number of plates”; the hydrospires do not cross over to the radials; the radials not only are not notched but they are not even in contact with either del- toids or ambulacra, being separated from both by the peculiar large and long bibrachial. The structure of the ambulacrum with its adambulacrals spanning the space between the deltoids, the absence of a lancet plate, and its peculiar wing plates and anal piece offer characters more than sufficient to separate the form from the Eublastoidea [Bather, 1899]. The structure of the ambulacrum on the other hand would at once suggest a position with the Edrioasteroidea as would also the torsion of the oral over the aboral areas of some 7 to 10 degrees toward the right, but the presence of brachioles, not to mention other differences of structure, would exclude it from that group. The form seems also to suggest several rather remarkable crinoid affinities. Here we have the marked basal invagination of many forms, the strongly crinoid radials, the group of interbrachials, and at least the suggestion of brachials in the pairs of plates assuming that position. These characters all exist on a differentiated aboral surface and the structure rather closely resembles the crinoid cup. The oral surface is just as extraordinary. Here we have the crinoid tegmen with its five deltoids as in Carabocrinus, its introduced anal ON SOME PELMATOZOA FROM CHAZY LIMESTONE OF NEW YORK _ IIQ plates, and its food grooves with their covering pieces leading to the mouth. We must not make too much of the absence of true brachials. The primary meristem in our species has already formed just such a linear series of single plates (the wing plates) on the upper sur- face of a ray. Does this radial series of single large plates give an excuse for the announcement of a new class of Echinoderms separate from all others? We may imagine our primary meristem to start a new wing plate and then push up between it and the last formed. This would give an outer brachial to a now ascending uni- serial arm. It would also require but a slight modification of the structures formed by this meristem to produce an ascending biserial arm with its fringe of pinnules. The ascending arms would at once retire the tegmenal brachioles from service and the modification or loss of these and adjacent structures would follow. In my description Go Cawayocrimus Peometricn’s 7 J suggested that the tegmen had plates bordering the lateral sides of the deltoids and thus underlying the food grooves. Figure 2, plate 1, of that report would suggest such a condition but the figure does not do justice to the specimen. The notches for the bases of the deltoids are more regu- lar than in the figure and the angles at the corners should have their outer sides running parallel with the lines taken by the missing food grooves. ‘These bordering plates might be homologous with the adambulacrals of Blastoidocrinus. The affinities of this genus seem to associate it most clearly with the Blastids but under neither grade as defined by Bather. I pro- pose a new order for this genus under the name of Parablastoidea and with the following characters. \ PARABLASTOIDEA Blastoidea with the theca more or less clearly separable into an oral and aboral surface. The aboral consists of three or more circlets of plates. Basals (unknown); five radials, in contact all around; five pairs of plates over the radials and supporting the distal ends of the ambulacra (bibrachials of Blastoidocrinus), and between them and completing the third circlet a group of smaller plates (interbrachials of Blastoidocrinus) arranged in one or more transverse rows. The oral surface possesses normally five ambulacra without a lancet plate but with adambulacrals meeting under the food grooves, with covering plates and with numerous ING Menotate Bal. An, Rept. 1903.