D. S. GEOLOGICAL SURVEY 



MONOGRAPH 56 PLATE XIV 



EXPOSURES AT QUINN DRAW, BIG BADLANDS, S. DAK. 



Showing summit of lower Oligocene Chadron formation (Titanotherium zone) and, at the top, base of younger Brule formation (Oreodon :;one). The 

 sandstone columns in the center indicate a river channel betvveen underlying and overlying claya. Am. Mus. negative 36012 



