494 University of Kansas Geological Survey. 



than H. grandis or H. eccentrica; margin narrower than in the 

 latter. The internal undulations or ridges are more prominent 

 in the young individuals. 



The young of this species seem to have nearly twice the thick- 

 ness of test as the young of the same size belonging to the other 

 species. This form occurs like the other species of this genus 

 in the lowermost Ornithostoma beds of Trego, Gove and Logan 

 counties. 



Haploscapha eccentrica Conrad. Plate xciii. 



Haploscapha eccentrica Conrad, 1875, U. S. Geol. Surv. Terr., vol. n, p. 24, 



pi. LXVII. 



Revised description: "Shell subovate, dorsal side straight, 

 hinge line thick, and shorter than in H. grandis. Concentric 

 ridges not as well marked, and less numerous. Outer smooth 

 margin showing a well-marked sinus. Cavity more profound. 

 Ridges passing more gradually into the margin, not ending so 

 abruptly as in H. grandis. Hood, two and one-half inches in 

 length ; length of shell, nine inches ; height of valve, ten 

 inches." H. eccentrica was placed under the subgenus Cuculli- 

 fera by Conrad, but I doubt if it has sufficient generic distinc- 

 tions to warrant such a classification. There is little doubt, 

 however, that it is a species distinct from H. grandis, with 

 which it is associated in the Ornithostoma beds. 



Jtadiolites maximus, n. ep. Plate cxv; also, cxix, fig. 1. 



Shell inversely conical ; lower valve three to four feet in 

 height ; outer surface marked by parallel longitudinal ridges 

 composed of overlapping plates. Inner surface smooth, show- 

 ing striations formed by intersection of plates and prisms. 

 Valve composed of circular plates placed one upon the other ; 

 plates composed of prisms filled with calcareous matter. Up- 

 per extremety of lower valve resembling a flange bent upward 

 and outward. 



Diameter of lower valve at top, 250 mm. ; thickness of outer 

 layer of shell, 75 mm. Prismatic layers of shell ornamented 

 with branching ridges upon the upper surface, with a corre- 

 sponding depression on the under surface. 



