PHYSICAL GEOGRAPHY. 13 



in order to collect both fossils and most interesting speci- 

 mens of crystallized selenite, without taking the trouble of 

 making diggings, it is only necessary to perambulate the 

 zone of plastic clay shortly after it has been washed by 

 heavy rains. Under such circumstances, should they b^ 

 favored moreover by the reflections of the sun, they will be 

 struck with the appropriateness of the designation of these 

 hills, as applied both by the voyageurs and Indians — name- 

 ly, of shining mountains. In truth, it is not unlikely that 

 these hills, a portion of them attaining an elevation of from 

 500 to 700 feet above the river, were some of those referred 

 to by the Sioux of the Missisippi, who, conversing with the 

 first white men who visited them, and long afterwards with 

 Capt. Carver, spoke of the Shining Mountains of the West. 



" These (so named) pseudo-volcanoes are not, however, 

 confined to the valley of the Missouri. Traces of them are 

 not unfrequently found over the more westerly regions, as 

 far as the upper portions of the rivers called by the Indians 

 Mankizitah and Washtey. The name of Mankizitah-ivatpa, 

 usually translated by that of " White-earth-river" (or simply 

 White river), means, more properly. Smoking Earth river ; 

 whence I have concluded that these indications of i^seudo- 

 volcanoes were at the same time evidences of the recurrence 

 of the upper members of the cretaceous formation, the limit 

 of which I have assigned as being somewhere eastward of 

 the Black Hills. The name of ' Mauvaises Torres' (bad 

 lands) has been applied to districts cut up into deep and in- 

 tricate chasms, from which the traveller could hardly hope 

 to extricate himself without the assistance of a good guide, 

 and that are doubtless due to the burning out of their 

 pseudo-volcanoes . 



" However this may be, there can be no doubt that the 

 region of country drained by these rivers which I have last 



