14 GEOLOGICAL SURVEY OF ALABAMA. 







feet high above the floor of the valley, and from 100 to 200 

 feet above the general level of the Coal Measures beyond. 

 This ridge is very narrow, the breadth of its base at the level 

 of the valley being only 600 to 700 feet. The sides very 

 steep, yet smooth ; the top sharp backed, scarcely a rod in 

 breadth, yet of almost uniform height. Denudation has had 

 but little effect on it. No wind gaps, or gullies, or areas of 

 abrasion are seen. Its symmetry is unbroken, save where 

 the streams rising in the fountain beyond have cut their 

 way through it into the valley below. The channels of 

 drainage here have evidently not been changed since they 

 were first established. 



The height and volume of this vertical ridge, or wall, are 

 nearly uniform for long distances, and it seems to be exactly 

 parallel with the axis of t T :e valley. This remarkable topo- 

 graphical structure is the south-eastern edge, or rim of Mur- 

 phree's Valley, and bears the local name of Straight Mountain. 



The vertical portion of this *iiarginal rim gradually dimin- 

 ishes in prominence toward the ends of the valley. Its 

 greatest elevation and volume being opposite that part in 

 which the Cambrian limestone is exposed ; that is irom a 

 little below Remlap, for fifteen miles north-east to a little 

 above the Champion Mines. 



Near the upper end of the valley the vertical rocks are 

 not seen ; apparently they have passed beneath the surface, 

 and the rim or edge of the valley is the face of the Coal 

 Measures, dipping for a short distance to the south-east, at 

 an angle of about 60, 



Red Mountain. This most important topographic as well 

 as economic feature of the valley lies generally to the west 

 of the central line of the valley, but near its head the Red 

 Mountain is about equi-distant from the two margins of the 

 valley. It is made up usually of three formations the 

 Clinton, the Black Shale and the lower member of the Sub- 

 Carboniferous. In many places a fourth underlying forma- 

 tion, the Trenton, is found along the inner or valley side of 

 the Red Mountain, extending in some cases almost or quite 



