518 GEOLOGICAL SUEVEY OF THE TEERITOEIES. 



Calamageas angulatus, Cope, loc. cit, p. 16. 



' The largest species, distinguished by tlie presence of a low ridge on 

 the centrum from the parapophysisto the middle of the centrum. Neu- 

 lal spine on the posterior half of the neural arch short, truncate. Hy- 

 papophysis short, ending in an obtuse point. Parapophysis larger than 

 in other species, nearly equal to the diapophysis. 



Measurements. 



M. 

 Length of ceutrnm 0.0030 



Diameter of ball, 5 *^^".«T^« 0017 



' ( vertical 0016 



Width between parapophyses 0024 



Depth of entire vertebra 0045 



Aphelophis, Cope, loc. cit.^ p. )6. 



Char. gen. — Similar to the preceding in the absence of acuminate diapo- 

 ishysial process, the zygosphene exceeding the articular extremity in 

 width, and the simplicity of the posterior border of the neural arch. 

 There are no longitudinal ridges, the hypapophysis being entirely want- 

 ing. The articular faces of the i)arapophysis and diapophysis continu- 

 ous without intervening concavity. 



Aphelophis talpiyoeijs. Cope, loe. cit., p. 16. 



Char. Hjyecif. — Yertebrse short and wide 5 the neural spine stouter and 

 more obtuse than in any other species here described, occupying less 

 than half the neural arch with its basis. Zygosphene wide, depressed, 

 "With nearly straight posterior margin, not sending any ridge backward 

 from the posterior face. Articular faces of centrum a depressed oval ; 

 ball looking upward, its axis- making 45° with that of the centrum. 

 Parapophysis not i)rojecting below centrum. 



Measurements. 



M. 



Length of centrum . . .' 0.0026 



Di-imeter of pnns ^rausverse • .0018 



i^iameter ot cnps, ^ ^.£^^(,^1 0012 



Width between paia j..ophyses .0017 



Depth of en tire vertebra 0034 



Width of zygosphene 0020 



Eepresented by three vertebrae of an individual about the size of C. 

 truxalis. 



CHAPTEE Y. 



THE LOUP FORK EPOCH- 



In the Pliocene strata already described, mammalian remains are 

 exceedingly abundant over limited areas; those of horses in an especial 

 manner. Those obtained are as follows : 



Species. 



Carnivora 4 



Perissodactyla 8 



Artiodactyla 7 



Proboscidia 1 



Testudinata 1 



Total 21 



