VEETEBEATES. 357 



ornate sculpturing extending over the greater portion of the coronal 

 surfaces, except in the convexity of the median prominence, which is 

 smooth and towards the apex finely punctate. The root forms a rela- 

 tively deep, strong, angular plate, nearly equal to the lateral diameter 

 of the crown as also in depth, the deeper face nearly plane, the opposite 

 side occupied by a broad depression terminating above in the strongly 

 produced basal margin of the concave face, inferior surface well-defined, 

 gently arched upward and beveled at a slight, angle to the horizontal 

 plane of the crown from the concave to the inferior margin. Lateral 

 diameter of crown about .80 inch, entire hight of tooth .6S, greatest 

 slope of crown in the convex face .50, greatest slope of crown in the 

 concave face .31, anteroposterior diameter of crown .3S iuch. 



A specimen of less robust proportions, in which the lateral extremi- 

 ties are greatly developed, presents a laterally elongated outline, the 

 median portion of the crown — though smaller and slightly eccentric 

 and, perhaps, more regularly obtusely conical and less produced over 

 the concave face— closely resembles that described above; the wings, 

 however, are extremely produced laterally, and traversed by a high 

 angular median ridge which is very gradually narrowed to the rounded 

 extremities; the concave face but slightly depressed vertically or about 

 equal in degree to the convexity of the opposite face which slightly 

 exceeds it in elevation. The coronal ornamentation is the same as 

 observed in the first mentioned variety, with the obliquely ascending 

 plicae perhaps a little more distinctly marked. The root forms a very 

 deep plate nearly vertical to the crown, rhomboidal in outline, contour 

 of outer and inner faces and basal surface similar to the base of the 

 first described teeth. Lateral diameter of tooth 1 inch, hight .58, 

 slope of convex side of median prominence .31, slope of concave side 

 .25, anteroposterior diameter .32. 



Associated with these teeth Mr. Springer has found'several speci- 

 mens of smaller size, ranging from half an inch to a quarter of an inch 

 in lateral diameter, the proportions and other characters of which seem 

 to prove their specific identity with the larger teeth above described. 

 These smaller examples, or at least some of them, have the median por- 

 tion of the crown less produced, and in very small specimens the coro- 

 nal surfaces are quite smooth and polished. The form is intimately 

 related to G. angulatus (X. and W. sp.), and, perhaps, more so to C. ele- 

 gam, X. and W., of the Keokuk limestone. It is distinguished, however, 

 by the peculiar sculpturing of the coronal surfaces and the obscure defi- 

 nition of the coronal folds. 



Position and locality : Fish-bed of the Upper Burlington limestone; 

 Louisa county, Iowa. 



