THE BADLAND FORMATIONS 



OF THE 

 BLACK HILLS REGION 



BY CLEOPHAS C. O HARRA 



INTRODUCTORY 



The badland formations of the Black Hills region have for 

 many years been the source of the most varied interest. They 

 are made up of rocks showing generally rapid disintegration 

 and owe their name to the peculiar nature of the type locality of 

 their exposure. 



The term "badland" does not lend itself readily to accu- 

 rate definition but custom and convenience permits its use in 

 harmony with the name Badlands as understood by the early 

 French-Canadian hunters and trappers who, imitating the poet- 

 ic "Ma-koo-si-tcha" of the Dakota tongue applied the name 

 "Mauvaises Terres" to the area southeast of the Black Hills ly- 

 ing along the White and Cheyenne rivers. The words were 

 meant to signify a country difficult to travel through chiefly be- 

 cause of the rugged surface arid general lack of good water. 

 For many purposes surface features have been the only criteria 

 recognized in defining the term but among scientific men "bad- 

 land formation" especially as used with reference to the North 

 Central Great Plains has approached specific importance and re- 

 fers, unless otherwise stated, to deposits of Tertiary age. This 

 does not imply that all Tertiary roeks and only Tertiary rocks 

 come rigidly under the badland class, but this is so generally 

 true in the Black Hills region that in this paper I consider the 

 terms synonymous, preferring to use the less technical term in 

 deference to the convenience of the non-technical reader. De- 

 posits other than those of Oligocene Tertiary and Miocene Ter- 

 tiary are not described. It is possible that Fort Union beds may 

 be represented within the area covered by the northern part of 

 the map since recent study seems to have shown their presence 

 in large areas in southwestern North Dakota where they make 



