GEOLOGICAL SURVEY OF THE TERRITORIES. 349 



T. A. Conrad, and add herewith his account of them. He thinks they 

 possess some resemblance to the Eudistes ; but whether truly related to 

 or belonging to that divisiouj he is at present in doubt. 



Fragments of these SaploscapJice are common in the formation, and 

 have been described by authors as portions of huge Inocerami. 



HAPLOSOAPHA, Conrad. 



Shell subovate or sub triangular; hinge long and straight, edentulous, 

 oblique ; curved, prominent ridges occupy the upper portion of the in- 

 terior, the ridges beginning and ending at a distance from the margins 

 of the shell ; a singular twisted callus composes the hinge, the back of 

 which is transversely ribbed. . 



H. GRANDis. — Length greater than height, hinge-line very long, ridges 

 concentric, about twelve in number, extending into the cavity under the 

 hinge. 



This shell. Professor Cope informs me, has been found 27 inches in 

 diameter. The posterior side of the right valve is elongated and dilated, 

 and the form of the shell is not unlike that of Meleagrina. The sub- 

 stance is fibrous or rather columnar, and much resembles that of Ca^pri- 

 nella as figured by d'Orbigny, except that the fibres are transverse. 

 The exterior is always concealed by a coating of rock and a crowded 

 mass of Ostrea congesta, and in some specimens they line the cavity of 

 the shell; the submargin is thick. No muscular imj)ression can be 

 traced unless the ridged part indicates its station. 



Subgenus Cucullipera. 



Shell with an upright, hood-shaped process on the posterior end of the 

 hinge. 



H. EXCENTRICA. — Ovato-triangular ; hinge-lineshort, very thick; con- 

 centric ridges profound, six in number ; hood strongly and irregularly 

 plicated ; cavity profound. 



This shell, with the same structure of substance as the preceding, is 

 very unlike it in form, and is represented by one valve only, while a 

 number of the i)receding species were found. In all specimens of the 

 two forms the right valve only was obtained. 



Whether it is allied to the family Eudistes of Lamarck is a question I 

 leave for others to decide. On the margin of one of the valves are at- 

 tached some small shells resembling HippuriteSy and the fibres of which 

 the shell is composed lie in broken masses on some valves and even 

 scattered like i^iles of pins. 



The hood of H. excentrica is 2J inches in height, and the height of 

 the valve 10 inches ; length, 9 inches. 



Accompanying these fossils were many specimens of inocer«??ii«sj9ro&- 

 lematicus, and a fragment of an undetermined si)ecies of the same 

 genus. 



