No. 112.] 45 



GEOLOGICAL, INCLUDING FOSSILS. 



DONATIONS. 



From the Hon. MOSES EAMES, of Rutland, Jefferson county, N. Y. 



Sndocekas pkoteiforme, Hall. Palseontology of New- York, Vol. I, 

 pa. 216, pi. 57, f. 1. 



This specimen is from the Trenton limestone, and was obtained 

 in the town of Cape Vincent, Jefferson county, N. Y. The frag- 

 ment is two feet long; and seven inches in diameter at the 

 greater, and four and a half inches in diameter at the lesser end. 

 The siphuncle, which is well defined at the lesser end of the 

 specimen, is sub-marginal, and two and one fourth inches in 

 diameter. 



The surface of the fossil is covered with impressions of Crusta- 

 cea, bivalve shells, corallines, &c., characteristic of the Trenton 

 limestone. Among them, the most important and interesting is 

 the matrix of a trilobite belonging to the genus Acidaspis of 

 Murchison (Odontopleura of Emmrich) ; it is three-fourths of an 

 inch in length, and distinctly exhibits the fimbrise, on the outer 

 margin of the maxillae; the elongated spines at the posterior 

 angles of the cephalic shield; the short spines at the sides of 

 the body, produced by an elongation of the lateral articulations ; 

 and the spinous margin of the caudal shield. 



Professor John Locke, in the American Journal of Science (Vol. 

 44, pa. 346, and also in vol. 45, pa. 223), describes a new trilo- 

 bite, obtained in the rock formation near Cincinnati (which is 

 equivalent to the Trenton limestone of New- York), as the 

 Ceraurus crosotus; and with which I consider our specimen 

 identical. 



