18 GEOLOGICAL SUKVEY OF ALABAMA. 



a very prominent and persistent ledge of hard gnarly rock, 

 often with bluffy perpendicular face 20 to 50 feet high. 

 This ledge is the great impediment to road making across 

 this mountain, it only can be surmounted at a few places. 

 The whole thickness of this member is about 100 feet. 



Following this is a series of flaggy and ripple-marked 

 sandstones, yellowish and reddish colored building stone, 

 with belts of intervening yellow clay, somewhat irregular 

 in volume, the whole making from 50 to 75 feet. 



Above this member and near the base of the conglomerate 

 next above it is, at least in places, a seam of coal of varying 

 thickness, but so far as seen not exceeding one foot thick- 

 This coal seam occupies the geological position of the 

 Cliff Seam., Etna. Seam-, &c., so often referred to and de- 

 scribed in Prof. McCalley's Report on the "PLATEAU 

 REGION OF ALABAMA" that no doubt of its identity is inter- 

 tained. 



The Lower Conglomerate caps and complete the series of 

 Lower Coal Measures. It is a rock so well and widely known 

 that minute description of it is unnecessary. It possesses 

 here its usual characteristics ; a massive, persistent rock, 

 varying in thickness from 50 to 100 feet, in some places, 

 composed almost wholly of well rounded pebbles, firmly 

 cemented together, and called Millstone Grit, in others the 

 pebbles are in bands and patches, or sparsely scattered 

 through the rock, while in other parts the pebbles are 

 wholly wanting, and the rock is merely a coarse-grained 

 sandstone. 



The series of Lower Coal Measures will be presented at 

 one view by the following : 



SECTION OF LOWER OR SUB-CONGLOMERATE COAL MEASURES. 



(11) FIRST, OR LOWER CONGLOMERATE 50 to 100 feet. 



(10) COAL ( ' Jliff seam Etna seam, dec.) 1 " 



(9) Flaggy sandstones and clay beds, 50 to 75 " 



(8) Shaly Cliff, 100 " 



(7) Signs of coal seam? shale, 35 " 



