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DESCRIPTION OF A NEW SPECIES OF STYLONURUS

FROM THE CATSKILL GROUP.

BY JAMES HALL.

Sometime during the year 1882 Prof. Gen. H. Cook of Rutgers College, State Geologist of New Jersey, called my attention to the carapace of a large crustacean in a mass of sandstone from the town of Andes, Delaware county, N. Y., which had been presented to the College Museum. At the same time Prof, Cook sent to me a plaster cast of the fossil, in relief, which preserved the characters of the surface in a remarkable degree of perfection.

I subsequently saw the original specimen in the museum of Rutgers College, and at a later period, through the kindness of the authorities of that institution, I have been allowed to have the specimens in my possession, for more critical examination and study.

The locality of the fossil is in the midst of the Catskill group, and the character of the rock alone indicates its geological horizon,

- The specimens of the rock, one retaining the impression and the other the relief of the carapace, are more than two feet across, each one having a thickness of several inches. Although there are in one of the slabs some cavities partially filled with ferruginous matter, and other ferruginous markings, I have been unable to detect any evidence of organic remains in any part of the mass. .

The rock, in its unweathered condition, is a fine-grained, olive-gray sandstone, weathering to a more distinctly gray color and becoming somewhat friable.

The accompanying description and illustration of the species will give an idea of the character of the fossil and its relations to its congeners previously known.*

* The first published notice of this fossil, so far as I am aware, appeared in the Trang. actions of the New York Academy of Sciences (Vol. II, p. 8, Oct, 188%), by Prof. D, S, Martin, under the title of a new Eurypterid from the Catskill Group. The notice was based upon a cast of the carapace in the N. Y, State Museum of Natural History, which had been labeled with name and locality by the author. The printer's error in spelling the name Stylomurus instead of Stylonurus, would be readily corrected by any one at all familiar with this class of fossils.

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STYLON URUS EXCELSIOR, n. sp.

Plate V, fig. 1. Carapace sub-elliptical, truncate behind; width at the base about two-thirds of the length; lateral margins gently curved outward from the base of the carapace to a point opposite the base of the palpebral arches, thence gradually incurving to the front of the carapace.

Eyes circular situated on a line just anterior to the center of the length; separated by a strong median ridge which, commencing nearly on a line with the posterior limits of the palpebral arches extends forward nearly one-half the distance to the anterior margin where it becomes merged in the general convexity of the surface; palpebral arches strongly elevated semi-circular, more regularly curving behind, where they are gradually depressed into the general contour; the anterior portion of the arch is narrower and terminates abruptly in a line almost through the center of the eyes; posterior angles of the carapace rounded; occipital ring moderately defined, anterior to which and separated by a transverse depression, is a central lobe with an intermediate and lateral lobe on each side with corresponding depressions.

Surface on the anterior part marked by strong elongate and confluent pustules which are arranged in concentric lines, becoming more individualized and directed backward and subimbricating on the posterior half; the markings on the occipital ring are more subdued than upon the general surface, except on the posterior margin which is ornamented by a row of strong spiniform nodes; the entire intermediate surface, as well as the surface of the nodes, is marked by fine scales; the surface included by the palpebral arches is marked by stronger scales which are not elevated into nodes; the concave spaces between the posterior lobes are marked only by the fine, scale-like ornamentation.

Abdomen and appendages unknown.

The greatest length of the carapace is two hundred and fifty-five millimetres ; width at base one hundred and ninety-five millimetres; width in a line through the bases of the palpebral arches two hundred and twenty-five millimetres, and across the anterior extremities of the arches one hundred and ninety-three millimetres; the diameter of the eyes is twenty-three millimetres; distance between the extremities of the palpebral arches, sixty-five millimetres.

This species is very different from the ordinary forms of the genus in the great anterior extension of the carapace and the prominence of the palpebral arches.

A restoration on the scale of Stylonurus Logani, Woodward, would make the entire animal over four feet in length.

Formation and locality. In the Catskill group; Andes, Delaware county, N. Y.

LIST OF SPECIES OF FOSSILS FROM AN EXPOSURE OF THE UTICA SLATE AND ASSOCIATED ROCKS, WITHIN THE LIMITS OF THE CITY OF ALBANY.

BY C. E, BEECHER.

Climacograptus bicornis.
Dicranograptus ramosus.
Diplograptus mucronatus.
Crinoid stems.
Trematis terminalis.
Leptaena sericea.

o subtenta.
Orthis testudinaria.
Zygospira modesta.
Avicula Trentonensis.
Cleidophorus planulatus.
Ambonychia undata.
Tellinomyia dubia,

o levata.
Lyrodesma poststriatum.
Ten undetermined species of Lamellibranchiata.
Hyolithes Americanus.

" Sp. ? Bellerophon bilobatus.

so cancellatus. Murchisonia gracilis. Eudoceras proteiforme. Orthoceras bilineatum ? Cornulites flexuosus. Plumulites sp.? Triarthrus Becki. Trinucleus concentricus.

Thirty-six species, several of which have not heretofore been noticed in the Utica Slate.

The well-known graptolite locality at Kenwood has been for a long time the only locality for fossils in the immediate vicinity of Albany, and has afforded but a single oboloid shell in addition to the graptolites. The discovery of strata furnishing an abundant and varied fauna is, therefore, of considerable interest.

The beds carrying these fossils are nearly vertical and situated north of the Dudley Observatory on the line of the New York Central railroad.

A CATALOGUE

OF THE

PUBLISHED WORKS OF JAMES HALL, LL.D.

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PART I.

BOOKS.

1. Geology of New York. Part IV, comprising the survey of the

Fourth Geological District; pp. 682, maps and plates. Albany,

1843. 4to. 2. Fremont's Exploring Expedition: Appendix A. Geological for

mations; pp. 295–303. B. Organic Remains ; pp. 304–310, 4.

plates. Washington, 1845. 8vo. 3. Palæontology of New York. Vol. 1 ; pp. xxiii, 338 ; plates, 100.

Albany, 1847. 4to. 4. Report on the Geology of the Lake Superior Land District. By

J. W. Foster and J. D. Whitney:
Lower Silurian System. Chapter 9, pp. 140-151. Washing-

ton, 1851. 8vo.
Upper Silurian and Devonian Series. Ibid. Chapter 10, pp.

152–166. Description of New and Rare Species of Fossils from the

Palæozoic Series. Ibid. Chapter 13, pp. 203-231. Parallelism of the Palæozoic Deposits of Europe and America.

Ibid. Chapter 18, pp. 285–318. 5 Stansbury's Expedition to the Great Salt Lake. Geology and

Palæontology ; pp, 401-414. Philadelphia, 1852. 8vo. 6. Palæontology of New York. Vol. II ; pp. viii, 362 ; 104 plates.

Albany, 1852. 4to. 7. United States and Mexican Boundary Survey (EMORY). Geology

and Palæontology of the Boundary; pp. 103, 140, 20 plates. Washington, 1857. 4to. Also published in American Journal.

of Science, 2d Ser. See vol. 24, pp. 72–86. New Haven, 1857. 8. Geological Survey of the State of Iowa. Vol. I, part 1. Hall

and Whitney. General Geology. Chapter II, pp. 35–44. Geology of Iowa. General Reconnoissance. Chapter III, pp. 45–46. Part II. Palæontology of Iowa. Chapter VIII, pp.

473–724, 29 plates. Albany, 1858. 4to. 9. Contributions to the Palæontology of Iowa, being descriptions of

new species of Crinoidea and other fossils (supplement to vol. I, part II, of the Geological Report of Iowa); pp. 1–92, 3 plates. Albany, 1859.

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