Allen.] 252 [January 21, 



denudation, which have been worn away nearly to the general level 

 of the plateaux on which they are located, leaving only a rim ot 

 blocks of scoriaceous matter surrounding a bare area of unaltered 

 and undisturbed shales. 



At a point on our trail, a few miles west of the Little Missouri, are 

 some deep gorges, where the above described metamorphism may be 

 seen on a grand scale, as also near the mouth of Powder Kiver. At 

 the latter locality a portion of the lignite bed still remains, and points 

 may be found where the burning of the beds ceased, and with it the 

 metamorphosed condition of the overlying shales. Such exposures 

 were seen on Custar's Creek, where is a fine exposure of the junc- 

 tion of the burned and unburned portion of one of the heaviest beds 

 of lignite we observed — a bed varying from eight to twelve feet in 

 thickness. The layer of cinders was fully three to four feet in thick- 

 ness, and the subsidence of the strata at the point where the combus- 

 tion ceased was plainly visible. 



The Bad Lands of the Little Missouri appear to present one of the 

 most extended areas of this remarkable metamorphism that has yet 

 been noticed. Here, with a breadth of twenty to thirty miles, these 

 appearances are said to be continuous for fully two hundred miles. 

 Throughout this vast area all the ridges and buttes are capped or 

 banded with the reddened and indurated shales. This, with the 

 generally chaotic appearance of the district, led Gen. Sully, it is 

 reported, when he crossed it in 1864, to compare it to " hell with the 

 fires put out." From the Sentinel Buttes, two high points situated 

 about twenty miles west of the Little Missouri, and nearly on the 

 boundary of Dakota and Montana Territories, the Bad Lands of the 

 Little Missouri can be overlooked ; the position of these buttes being 

 just to the westward of the western border of this great igneous 

 district. It terminates quite abruptly along a line running nearly north 

 and south, so that to the eastward is one vast expanse of red undu- 

 lating surface, as far as the eye can see; at this distance only the bare 

 verdureless crests of the red-capped buttes and ridges being visible. 

 The view is, hence, one of utter barrenness, yet wild and picturesque. 

 A sea of fire, with its billows " fixed and motionless," is the simile at 

 once suggested as mile upon mile of this reddened district meets 

 the eye. 



Other areas of large extent and similar appearance, when seen 

 from a distance, also occur along tbe Yellowstone, near the mouth of 

 the Powder River, along a considerable extent of Powder River itself, 



