1874.] 259 [Allen. 



streams. Hence it must have begun anterior to the close of the 

 drift period, its beginning antedating the terrace epoch; and that it 

 still continues there is abundant evidence. 



Of the explorers who have visited this region, Lewis and Clarke 

 appear to have been the first who gave any intelligible account of 

 these interesting phenomena. They not only described in consider- 

 able detail the appearance of these metamorphic materials, as the 

 preceding quotations from their narrative have already shown, but 

 correctly ascribed their origin to the combustion of the coal beds of 

 this region, being guided in part to this decision, doubtless, by find- 

 ing some of them actually on fire. Nicollet, in his account of his 

 journey up the Missouri, in 1839, refers to these burning coal beds, 

 but he seems not to have seen them himself, and his knowledge con- 

 cerning them was in some respects vague and erroneous, and his 

 theories respecting their origin rather visionary. He says: 



" I have now reached the proper place to treat of a very interest- 

 ing phenomenon observed in the midst of this cretaceous group. It 

 manifests itself by the occasional appearance of a dense smoke at 

 the top of some conical hill, or along a line of country bounded by 

 the horizon, so as to awaken the idea of distant volcanoes ; hence, 

 I have chosen to call them pseudo-volcanos. The smoke from these 

 hills and the crevices in the plastic clay, is said to last at the same 

 spot for a long time — say two or three years ; indicating at them a 

 large accumulation of combustible materials. It is not, to my knowl- 

 edge, accompanied by luminous vapors, and is silently wafted along 

 the valley, which it mournfully shrouds." "Before proceeding to 

 account for the appearances and circumstances attending these 

 smoking hills," he continues, '' I must add a few more facts concern- 

 ing their traditional and recorded history. There were none when 

 we ascended the Missouri, in 1839; and so would seem to have been 

 the case at the passage of Lewis and Clarke at the beginning of this 

 century. 1 But previous to my arrival, since the memorable expedi- 

 tion last referred to, and during a period of three years, they were 

 seen (as my information goes), by many intelligent persons engaged 

 in the fur trade, all of whom are naturally observant, and most of 

 them of unquestionable authority. I have no doubt, therefore, of the 

 existence of these hills." " I believe," he says further, " and it is 



1 An error. See Lewis and Clarke's Exped. Vol. I, p. 181. 



