PRELIMINARY MAP OF THE BADLAND FORMATIONS OF THE BLACK HILLS REGION 



Chiefly from the Survey of : 



Mostly Lower Miocene. Known to contain also 

 Middle Miocene, Upper Miocene, Pliocene, and 



(1905) a« Modified by Matthew and Thomson 



Middle and Upper Oligocene. Brule Formation (Oreodon 

 and Protoceras Beds). 



-differentiated Oligocene (Chiefly Chadron formation). 



Lower Oligocene. Chadron Formation (Titanotherium 



