98 FROSTBURG COAL FORMATION. 



itself followed by a thick bed of shale, with a conforming 

 stratification. 



It is very probable, that the form of Wills' mountain is due 

 to a force acting from beneath, and that the carboniferous 

 limestone, resting upon the flanks of the mountain, formerly 

 constituted a continuous covering, whose upper limits may be 

 represented in the manner which is seen by the dotted line 

 a a a on the section. It may be readily conceived, that the 

 portion now wanting, might have been removed in the course 

 of time, when we take into the account the solvent power of 

 carbonic acid, aided by the ruptured condition of the lime- 

 stone. The greater amount of the elevation must have taken 

 place before the coal series was deposited, because the eastern 

 edges of the carboniferous rocks crop out on the eastern face 

 of Dan's mountain near the summit, and the basin shape 

 proves that there must have been rocks on the eastern side 

 considerably higher than exist at present. Another evidence 

 of the elevation having taken place before the coal era, is in 

 the fact, that the coal series bears the strongest evidence of 

 not having been disturbed by subterraneous movements. 

 There is no appearance of a fault or dike; on the contrary, 

 the same bed at a distance of fifteen miles, and at the inter- 

 vening points, is found just where it should be if it had never 

 been deranged by partial movements ; and we can hardly 

 imagine that the upward motion was every where directly 

 vertical so as to elevate the beds without the least derange- 

 ment; the amount of elevation must have been at least 2400 

 feet, that being the elevation of the highest part of the old 

 red sandstone. At the epoch of the completion of the coal 

 formation, no mountains existed in this district where we 

 now find Dan's mountain and the Savage. They are the 

 result of denudation by water, which perhaps required many 

 series of years, and a countless number of floods in the 

 Potomac and Savage rivers and other streams to produce. 



