The Black-Tail Deer 155 



acter with rounded hills and gentle valleys, dotted 

 here and there with groves of trees; or the hills 

 may rise into high chains, covered with an open pine 

 forest, sending off long spurs and divided by deep 

 valleys and basins. Such places are favorite resorts 

 of this deer; but it is as plentiful in the Bad Lands 

 proper. There are tracts of these which are in part 

 or wholly of volcanic origin; then the hills are 

 called scoria buttes. They are high and very steep, 

 but with rounded tops and edges, and are covered, 

 as is the ground round about, with scoriae bowlders. 

 Bushes, and sometimes a few cedar, grow among 

 them, and though they would seem to be most 

 unlikely places for deer, yet black-tail are very fond 

 of them, and are very apt to be found among them. 

 Often in the cold fall mornings they will lie out 

 among the bowlders, on the steep side of such a 

 scoria butte, sunning themselves, far from any 

 cover except a growth of brushwood in the bottom 

 of the dry creeks or coulies. The grass on top 

 of and between these scoria buttes is often very 

 nutritious, and cattle are also fond of it. The 

 higher buttes are choice haunts of the mountain 

 sheep. 



Nineteen-twentieths of the Bad Lands, however, 

 owe their origin not to volcanic action but to ero- 

 sion and to the peculiar weathering forces always 

 at work in the dry climate of the plains. Geo- 

 logically the land is for the most part composed 

 of a set of parallel, perfectly horizontal strata, of 

 clay, marl, or sandstone, which, being of different 



