DESCRIPTION OF A NEW SPECIES OF STYLONTJRTJS 

 FEOM THE CATSKILL CROUP. 



BY JAMES HALL. 



Sometime during tne year 1882 Prof. Ceo. H. Cook of Rutgers Col- 

 lege, State Geologist of Xew Jersey, calledlny attention to the carapace 

 of a large crustacean in a mass of sandstone from the town of Andes, 

 Delaware county, X. 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 con- 

 geners previously known.* 



*The first published notice of this fo«sil, so far as I am aware, appeared in the Trans- 

 actions of the New York Academy of Sciences (Vol. II, p. 8, Oct , 1882), 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. Tbe printer's error in'spellins 

 the name Stylomurus instead of Stylonurus, would be readily corrected by any one at all 

 familiar with this class of fossils. 



