268 The America a Geologist. May, 1896 
frmii tliis horizon. Professor Cope in his one published hook 
on "The Tertiary Vertebrata" has described species from 
twelve genera ; suffice to say, however, that their abundance 
and variety are much greater than from the next lower hori- 
zon, the White River. The structural advance, too, over the 
preceding or next lower horizon is also very marked. 
Jt again gives me much pleasure to acknowledge my great 
indebtedness to Dr. W, B. Scott for his assistance and advice, 
in preparing this comparative memoir, and for the free use 
of material from the Princeton museum. 
TEMNOCYON. Cope. 
T a 1 o n o f t h e i n f e r i o r sectorial is t r e n c h ant. 
1 n 1' e r i o r s e c o n d m o 1 a r has t r e n c h a n t c r o w n 
a n d a a i n I e /• n a / c u s p s. 
Dental formula i ^ c \ pj m ^- 
The type consists of portions of three individuals, two rami 
and the anterior portion of the skull, to which Cope ( No. 1. p. 
903) has given the name T. altigenis. 
Temnocyon ferox Eyerman (No. i. p. .'520). 
Larger than the type species. Cranium unusually well de- 
veloped and considerably longer, but of less transverse diam- 
eter than the type species. Palate vaulted. Small antero- 
posterior development of the true molars. Superior premolars 
equal in antero-posterior diameter and greater in transverse 
diameter than in the type. Unusual development of cingulum 
on the first true molar and the unusual position of m^ with 
reference to nu. In the inferior dentition the weak develop- 
ment of v7l in height, and the antero-posterior development as 
compared with the transverse. The small size of the metaconid 
of nul and the regular contour of its crown. And finally tin 
extraordinary development of the pollex and hallux. 
Description. — The unusual elongation of the cranium (fig. 
1) is perhaps best illustrated by comparing the length thereof 
with the transverse diameter of the palate in the type species 
and T. ferox. The diameter of the palate is one-fifth the 
length of the skull, wdiereas in the type ( T. altigenis) this di- 
ameter is less than one-third the length, or in other words the 
length of the skull of T. ferox is nearly one and three quarter 
times greater than that of T. altigenis, yet the diameter of 
the palate of the former (58 mm.) is less than that of the 
