24 PALEONTOLOGY OF NEW-YORK. 



40. 2. ILLiENUS CRASSICAUDA? 



Pl. IV. (bis). Fig. 1.3. 



Entomostracitcs crassicanda. Wahlenberg in Nov. Act. Peg. Soc. Upsal. 1S21. Vol. viii. pag. 27. tab. ii. ; 



pag. 294. tab. vii. fig. 5, 6. 

 Illamus crassicauda. D.m-man, K. Vet. Acad. Handl. 1826. Pag. 65. tab. v. fig. 2 a - e. 

 — — HisiNGER, Pet. Suecica, 18.37. Tab. iii. fig. .5. 



Fragment of buckler. Large, sub-hemispherical, gibbous, very thick and strong ; front 

 margin involute. 



The portion remaining is essentially the central lobe of the buckler, the lateral portions 

 having separated at the sutures. The specimen is more gibljous than common ; but on 

 comparison with the figures above quoted, and with a perfect specimen from Russia, there 

 appears to be no reason to doubt the specific identity. 



Position and locality. In subcrystalline oolitic limestone at Chazy in Clinton county, and 

 in Galway, Saratoga county. 



41. 1. ASAPHUS? OBTUSUS (?i. SJ9.). 



Pl. IV. (bis). Fig. 14. 



Caudal extremity semicircular, twice as wide as long ; surface finely granulated or 

 smooth ; marginal expansion even, and not depressed as in Isotelus ; central lobe faintly 

 visible by a gentle depression on each side ; no marks of articulations. 



This fossil varies from Isotelus, in the extremity being destitute of the apparent articula- 

 tions which are seen in species of that genus ; and also in the marginal expansion being 

 plain, and not depressed near the margin, as well as in being punctulated, and exhibiting 

 none of those fine linings seen in the margin of Isotelus, Ill^enus and Bumastis. 



This fossil bears some resemblance to llie caudal extremity of Jisaphus palpebrosus, but 

 the central lobe is less distinct than in that species. The middle lobe is less distinct, and 

 the whole shell more evenly convex and smooth than any specimens of the Isotelus of 

 the Trenton limestone. 



Position and locality. This species occurs in the compact limestone near the base of the 

 formation, and where the rock is but little changed from the character of the Calciferous 

 sandstone. It has been found only at Chazy village, Clinton county. (Stale Collection.) 



42. 2. ASAPHUS MARGIN ALIS («.*yj.). 



Pl. IV. (bis). Fig. 10. 



Caudal extremity semi -elliptical, distinctly three-lobed, marked by 7 or 8 distinct 

 pseudo-articulations, whicli are duplicate on the lateral lobes ; articulations not reacliing 

 the margin, but terminating in a cruslaceous marginal expansion, which is depressed or 



chaiUR'lk'd near tlic edge as in Isotelus ; surface granulaled. 



