Description of a new Trilohite. 421 



are nearly equal to eacli other. The glabella is distinctly sepa- 

 rated from the cheeks by a narrow, deep groove, which extends 

 all round. From the anterior lobe on each side a narrow filiform 

 ridsfe curves outwards and backwards on the fixed cheek to the 

 edge of the portion preserved. The eyes appear to be situated 

 just where these ridges terminate as represented in figure I. 

 Judging from the portion of the eye preserved in a detached 

 cheek-plate, its form is semi-annular, and its length at least one- 

 fourth that of the glabella. Caudal shield nearly as large as the 

 head, its width scarcely equal to half its length ; the lobes nearly 

 equal ; the middle lobe very convex with five sharp transverse 

 grooves ; the side lobes somewhat flat, and each with five 

 grooves. 



The largest head discovered is exactly two lines in length. 



The course of the facial suture has not been ascertained. The 

 surface of the glabella in one of the specimens appears to be 

 smooth, but in none of the others can it be distinguished. 



The specimens are mostly in a clayey layer, which is full of 

 fragments of all degrees of perfection ; in one specimen I counted 

 ten heads and three tails, all in a fair state of preservation. In 

 two instances, I have found the casts of maxillary plates, show- 

 ing distinctly the elevated margin ; of one of which I give a 

 figure. 



The original specimens were collected, (at High Bridge, near 

 Keeseville, N. Y.,) in August, 1856, while on a geological excur- 

 sion with Col. Jewett of Albanv, but were not recoo-nised until 

 July, 1857, when a second visit to the locaHty secured a few 

 casts in the solid sandstone, none of the clay layer being ob- 

 tained. By the kindness of Professor Dana, the specimens were 

 presented at the Am. Assoc, for Adv. of Sci. at Montreal, but 

 were not recognized as belonging to any kno^n species. Since 

 that time, I have looked for descriptions, but cannot find any to 

 correspond. 



At the same locality, I also procured the cast, of a Pleurotomaria, 

 and one of what seems to have been a plate from the stem of a 

 crinoid. 



New Haven, June 15th, 1860. 



Note hy E. Billings. — Mr. Bradley having favored me with a 

 view of his very interesting specimens, I think there can be no 

 doubt but that they belong to the genus Conocephalites. If thi 



