U. S. GEOLOGICAL SURVEY 



MONOGRAPH 55 PLATE CLXXIII 



SKULL OF BRONTOTHERIUM GIGAS ELATUS 



One-fourth natural size. (See p. 568, also PI. CLXXIV.) Skull referred to Brontotherium gigas (Am. Mus. 492), Cheyenne River badlands, 

 S. Dak., Chadron formation. The horns are much longer than in B. hatcheri but not so slender as in the type of Titanops elatus. The width 

 and flatness of the buccal expansion of the zygomata are somewhat increased by crushing 



