1/4 Bulletin of Laboratories of Dcnison University. [Voi xii 



again in the openings on Reynolds mountain, 8 miles northeast 

 of Cave Spring. (See Fig. 15.) 



Manganife7'oiis Stained Chert. — Where the chert is mixed 

 in large proportion with the ore-bearing clays, it is often more 

 or less stained with the manganese. This may occur as thin 

 films or layers of the manganese oxide coating the loose chert- 

 fragments, or as stringers and veinlets filling the cracks in the 

 chert. The proportion of staining to chert is quite variable. 

 In many cases it amounts to only a mere film ; in others, the 

 veins filling the cracks are quite thick. This has resulted from 

 the free percolation of manganese-bearing waters through the 

 loose cherty clays. Sometimes, that part of the chert not im- 

 pregnated has been entirely or partially removed by decay, 

 leaving a mass of siliceous manganese-ore of various shapes. 



Occurrence of the Ores. — The occurrence of the manganese 

 in this area is closely similar to that in the Cartersville district, 

 already described. (See Figs. 6. 7 and 15.) The ores differ 



Fig. II 



Section through the Chumler Hill Mine, Georgia, Showing the Mode of 



Occurrence of the Manganese-Bearing Clay. (After Penrose.) 



A, sandstone ; B, manganese-bearing clay. 



Horizontal scale, \\n. ^= ]4r mile. Vertical scale, i in, =: 400 ft. 



principally in occurrence from those in the Cartersville district 

 in {a) their intimate association >vith the cherty beds and clays 

 of the upper part of the Knox dolomite, in {Ji) being limited to 

 the residual clays derived from only one formation, and ic) be- 

 ing stratigraphically above those of the Cartersville district, oc- 

 curring in the clays of the Knox dolomite and not found at all 

 in the clays of the Weisner quartzite and Beaver limestone, 



