October, 1841.] 109 



already stated, abounding in characteristic organic remains of great 

 beauty. The extent of this locality is not yet known ; it is probable 

 that it occupies a very large area, and is destined to become one of 

 the most interesting and prolific fossil localities that has tempted 

 the enterprise of geologists. These fossils are remarkable alike 

 for their admirable preservation and their great beauty ; the latter 

 being much heightened by the presence of an opalescent nacre 

 which has been rarely noticed in the other cretaceous beds of this 

 country. 



Second series, from the lower cretaceous beds, or ferruginous 

 sand of New Jersey and Delaware. 



Ammonceratites. 



A. Conradi. Shell with an entire whorl, somewhat compressed, 

 with numerous, distinct, slightly curved costse, which diminish 

 and become almost extinct at the internal peripheral margin : 

 external periphery sub-angular, and undulated by the transit of 

 the costge. 



This specimen is a cast in a dark grey ferruginous sand, charged 

 with minute scales of mica. The terminal end is nearly complete, 

 and is almost on a line with what appears to have been the mouth of 

 the shell, and the two approach within a quarter of an inch of each 

 other. Diameter 2 inches. 



This is the first example of an Ammonceratite found in the 

 United States. It was obtained from a marl pit near Arneytown, 

 New Jersey, by Mr. Conrad, in whose name I gladly introduce it 

 to public notice. 



This genus is characteristic of the European chalk, having been 

 found both in England and France, in deposits of that age ; thus 

 affording another evidence of the analogy between the cretaceous 

 deposits of the old world with the marl strata of the new. 



Hamites. 

 H. annulifer. Shell small, cylindrical, equal; the external two- 



