1N0CERAMUS CANADENSIS. 



335 



In Formation No. 4 of the Cretaceons beds in Nebraska 

 there is a species something like this, which Dr. Hayden 

 and I have described (but not yet published) under the 

 name of A. subtrigonalis. The species now before me, 

 however, is much more compressed, and more rounded 

 in outline. It differs from A. tellinoides of Morton 

 (Synop. Org. Eem., p. 61, pi. v. fig. 11), in being 

 straighter on the cardinal side, and in having the umbo 

 of the upper valve much less prominent and gibbous. 

 Named after Mr. John Fleming, one of the gentlemen 

 connected with the Saskatchewan expedition. 



Locality and position. — Little Souris Eiver, in soft lead- 

 grey argillaceous rock, or indurated clay, probably of 

 the age of the fourth division of the Cretaceous Series in 

 Nebraska.] 



Inoceramus Canadensis. (N. S.) 



[Shell broad, oblong-oval, compressed, apparently very 

 nearly equi- valve ; anterior side rounded ; posterior side 

 longer and more broadly rounded or sub-truncate ; base 

 forming a semi-oval curve ; hinge straight, of medium 

 length ; beaks small, compressed, scarcely rising above 

 the hinge line, located near the anterior side, not very 

 oblique ; surface ornamented by small, obscure, irregular 

 concentric undulations, and fine closely arranged rather 

 indistinct lines of growth, which are generally only seen 

 on the outer fibrous layer. Length of largest specimen 

 about 3-35 inches ; height near 2*80 inches. 



The specimens of this species in the collection are im- 

 perfect, but retain enough of its characters to show it is 

 distinct from any of the known species in the Nebraska 

 formations. It resembles somewhat L Sagensis, Owen, 

 (Eeport, Wisconsin, Iowa, and Minnesota, tab. vii. fig. 3,) 



