492 University of Kansas Geological Survey. 



longest diameter. The shell is sometimes free from adhering 

 form, but usually has Ostrea congesta attached. 



These forms are abundant in all the exposures of the Or- 

 nithostoma beds which I have visited in the state. Next to 

 Ostrea congesta, they are the most abundant forms in the Nio- 

 brara Cretaceous of Kansas. 



Inoceramus truncatus, n. sp. Plate cxiv. 



Description : Shell large, somewhat cordate in outline, thick, 

 moderately convex, convexity in antero-central region ; hinge 

 long, straight, formed by reflex fold of shell, not marked, smooth, 

 anterior lateral margin forming a lobe. Shell smooth, marked 

 by small pits on the exterior surface, probably made by some 

 burrowing animal ; interior of shell smooth, marked by a promi- 

 nent groove near the margin ; exterior surface marked by broad 

 undulations running parallel with the longitudinal axis ; pos- 

 terior margin truncated, but having a rounded lobe in the cen- 

 tral portion of the truncated region. Thickness of shell in 

 central region from eight to twelve mm., gradually decreasing 

 in thickness as the margin is reached. Length of longer axis 

 in adult, three feet ; height, from one to one and one-half feet. 



The adult specimens of this species are difficult to obtain, but 

 young specimens are obtained more easily. In describing this 

 species, I have used adult specimens as seen in the field and a 

 young individual collected from the Niobrara outcrops on the 

 Saline river, north of Ellis. This form, like Inoceramus platinus , 

 which it most nearly resembles, is very abundant in the 

 Ornithostoma area of Kansas, in Jewell, Phillips, Gove, Trego 

 and Ellis counties. This species is comparatively free from 

 adhering forms, but Serpula tenuicarinata is often found attached 

 to it. 



Haploscapha grandis Conrad. Plate xciv. 



Haploscapha grandis Conrad, 1875, U. S. Geol. Surv. Terr., vol. n, p. 23, 



pi. LXVI. 



Original description : " Shell subovate or subtriangular, hinge 

 long and straight, edentulous, oblique ; curved, prominent 

 ridges occupy the upper portion of the interior, the ridges be- 



