294 



NEW YORK STATE MUSEUM 



Elasmatium gowandense sp. nov. 



Plate 12, fig. 21-29 



Shells of rather small size having the characters above set forth. The 

 interior plates or ridges of the left valve are generally rendered conspicuous 

 by the flattening of the test in the shale, breaking along the edges of the 

 plates and leaving them standing out above the surface of the shell. This 

 crushing, which is usual in the specimen, generally folds it along the 

 umbonal ridge, obscuring but not concealing the smaller plate beneath. 



Observations. To the relations of these shells, if the valves here 

 described prove to belong together, we can gain little clue. The clavicle 

 bearing left valves suggest some of the taxodont genera like Nuculites, but 

 there is a total loss of taxodont characters. The shells are found freely in 

 association with Kochia and Loxopteria. 



Habitat. Genesee province; Chautauqua subprovince. In the shales, 

 at Gowanda, Cattaraugus co., and at Walnut creek, Forestville and Little 

 Canadaway creek, Chautauqua co. 



Genus buchiola Barrande. 1881 



V e n er i c ar d i u m v. Buch. 1832 



Gl v pt oc a rd ia Hall. 1885 



C a r d i u m, C a r d i o 1 a, A v i c u 1 a of authors 



Fig. 11 Camera sketches of the hinge line in B u c h i o 1 a re t r o s t r i a t a showing the 

 irregular denticulations on the edge 



Obscure as are the structural characters of these shells, yet the peculi- 

 arity of their ornament alone justifies their distinctive designation. This 

 feature consists in few and broad plications crossed by fine lines caught up 

 into festoons on the summits of the ribs. Even in this respect, however, 



