410 O. C. Marsh—New Tertiary Mammals. 
The basal ridge, also, is much less developed on the inner side 
of the upper molars. Upper incisors were present, and one of 
the lateral ones was greatly compressed, and its crown very 
short, as in the existing R. Javanicus. 
Measurements. 
Antero-posterior diameter of penultimate upper molar,... 27° ™™ 
OV OO CinnON 8 a on Fike ol es wa 36° 
Antero-posterior diameter of first upper true molar, ----- 26° 
IAI RD, TI oe en ovina tne 34°5 
Antero-posterior diameter of first upper premolar, - - -- --- 20°6 
Transverse diameter, .-.._...---- 7 
Antero-posterior diameter of upper incisor, 21 
Transverse diameter, .___- .. Roe ba 
The remains on which this species is mainly based were 
found, in November, 1871, in the John Day Valley, Oregon, by 
Mr. G. G. Lobdell of the Yale party. 
Rhinoceros Oregonensis, sp. nov. 
of the Miocene species, is indicated by portions of several indi- 
viduals which were found by the Ya 
This species appears to have been about two thirds the size 
of R. crassus Leidy, from essentially the same geological horizon. 
Yale College, New Haven, April 24th, 1873. 
