Hayden.] 4'^" [iMaj-ti, 



Desaription. — Tootli large, laterally elongated, moderately thick (?), ex- 

 tremities rounded; crown slightly arching from the lateral angles and 

 curved laterally, anterior face slightly convex vertically and rounded at 

 the crest, which was probably more or less obtuse; the anterior face of 

 the crown was apparently undulated along its crest, the obscure sulci may 

 have reached half the distance from the crest toward the base, and at the 

 median line a very shallow depression, about as high as it is wide at the 

 base, reaches upward about two-thirds the height of the crown, and seem 

 to interrupt the continuity of the basal folds, which, however, may not be 

 persistent or of speciiic importance; basal band narrow^ linear, with two 

 or three imbricated folds, and parallel with the base of the root; surface 

 coarsely punctate. Eoot nearly as wide as the crown, its anterior face 

 deeply channeled by an angular transverse furrow, with a low ridge tra- 

 versing the lower portion from one extremity to the other, below which 

 it is beveled to the outer basal edge. 



Inches. 



Greatest breadth, about 1.60 



Height, 50 



Greatest height of anterior crown face, 22 



In outline the above species bears a somewhat marked resemblance to 

 C. loriformis, N. and W., from the Keokuk limestone; but it differs from 

 that form in having the anterior face of the crown relatively higher, its 

 crest undulated and less parallel, and its bow-shaped outline viewed from 

 above, as well as in the more vertical concavity of the outer aspect of the 

 root. It is not improbable that the basal angle of the posterior crown 

 face was quite prominent, and the vertical concavity of that face of the 

 crown must have been considerable, judging from the arched character 

 of the opposite face, and in this respect somewhat resembling G. cinct-us, 

 Agassiz, though the present species is not acuminate, the coi^onal band 

 not nearly as wdde as in that species, and the tooth is not as thick and 

 massive. 



Form, and Loc. — Upper Coal Measures, Bennet's mill, near Nebraska 

 City. 



Genus XYSTRODUS, Agassiz (ms.) 

 Xystkodus? occidentalis, n. sp. 



The collection affords an interesting little Deltoid tooth, which, I be- 

 lieve, has not been heretofore described. Unfortunately, the specimen is 

 quite imperfect, and, although its specific characters permit of descrip- 

 tion, its generic affinity remains somewhat in doubt. 



Description. — Terminal tooth small, subtrigonal in outline, little nar- 

 rower than long, but slightly inrolled, flattened or gently depressed above ; 

 the straight side is abruptly beveled, and from its edge the crown gently 

 inclines to the opposite oblique margin, which is very slightly raised; the 

 border extremity is thickened, forming a well defined continuous mar- 

 ginal border, which rapidly descends upon the inner side and gently slopes 

 into the shallow depressed space in front; toward the terminal extremity 



