Art. IX.] Watson, Manganese Ore- Deposits of Georgia. 157 



HjO at 100° C, - - - - - • - - None 



HjO above ioo° C, ------ - 0.31 



FeSj, - - - - - - - - - I 50 



BaSO^, --..----. 446 



Total, ........ 99.92 



The Beaver Limestone. — The main belt of tlie Beaver lime- 

 stone lies along the western base of the Weisner quartzite 

 ridges. A second, but smaller, area of the limestone extends 

 from Grassdale southward to the line of the Western and At- 

 lantic railroad, and is indicated near the western margin of the 

 map. Exposures of the fresh limestone are rarely seen, since 

 it is readily soluble, resulting in the insoluble residue forming a 

 thick mantle of deep-red soil. The formation is readily traced, 

 however, from the resulting red soil. Fragments of the quartzite 

 in all stages of decay, derived from the adjacent higher quartzite 

 ridges on the east, are admixed in some quantity with the 

 decay derived from the limestone. The few exposures of the 

 limestone met with indicate a semi-crystalline, gray, magnesian 

 limestone, containing, as Hayes states, occasional masses of 

 chert, becoming shaly in places. Hayes^ estimates the thick- 

 ness of the limestone to be not less than 800 to 1 200 ft. 



These two formations, the Weisner quartzite and Beaver 

 limestone, are of considerable importance as ore-producing for- 

 mations in the Cartersville district, as a majority of the ore- 

 deposits are associated with them. The manganese-ores occur 

 with about equal frequency in the residual decay of the two for- 

 mations. 



The Conasauga Shale. — Next above the Beaver limestone 

 is the great thickness of the Rome and Conasauga sandstone 

 and shale (Oostanaula shales of Spencer). The main outcrop 

 of the shale occupies the northwestern part of the mapped area. 

 A continuous band of the exposed shale extends southward 

 from the main outcrop to the line marking the position of the 

 Cartersville fault. The southern half of the band, which ex- 

 tends several miles in a north, south and west direction from 

 Cartersville, is greatly widened. 



' Trans., xxx., 406 (1901). 



