18 GEOLOGICAL SURVEY OF ALABAMA. 



Generally the pebbles are, small, white and well rounded. 

 Occasionally more angular fragments, and pieces of carbonate 

 of iron, form a breccia. In other parts the pebbles are irregu- 

 larly scattered, or occur in patches and irregular streaks. A 

 large portion of the rock is usually a stratified sandstone, 

 and affords good building rock, which will be referred to 

 again in its proper place. 



Beneath this conglomerate occur shaly and soft rocks from 

 twenty to fifty feet thick, resting on the Carboniferous Lime- 

 stone. It is very surprising that there should be here only 

 this insignificant amount of strata ' between the limestone 

 and the conglomerate. This is the place of the sub-con- 

 glomerate coals, whicji in Tennessee, and many parts of Ala- 

 bama, are of the first importance. Twenty miles east, along 

 the face of the Raccoon, (or Blount Mountain, as it is there 

 called,) and the Chandler Mountain, this stratum is from 

 500 to 800 feet thick. It there carries four seams of coal. 

 Three of them perhaps unimportant; but the upper one r 

 where cut, measured three ieet eight inches thick. And yet 

 in so short a distance, this stratum is reduced to an average 

 of about thirty feet. As might be expected, this thin stratum 

 holds no known workable seam of coal. At only one place r 

 where the Blackburn Fork of the Little Warrior cuts through 

 this rim, was any coal found in it. That was in an irregular 

 stratum of slate, with a still more irregular seam of coal 

 never exceeding three inches thick. 



These lower Coal Measures are always characterized by 

 irregularity in their thickness, and in the thickness of their 

 coal seams. A short distance may, therefore, make a great 

 difference in both, yet it is not probable that they will be 

 found of much value on this side of the valley- Above the 

 lower conglomerate, the higher, or intra-conglomerate, or 

 super-conglomerate Coal Measures are found, increasing in 

 thickness toward the synclinal axis, and corresponding with 

 the same measures on the south-east side ol the valley, which 

 have been described in a previous report. 



It may, however, be here repeated, that the 2,000 feet of 

 coal strata, assumed to have been swept away on the north- 



