Art. X.] Watson, Yellow OcJier- Deposits of Georgia. 211 



in having extremely irregular outlines. This sand, as might be anticipated from 

 the microscopic structure of the slightly altered quartzite, is evidently composed, 

 not of the original grains of the rock, but of detached portions of the irregular 

 siliceous skeleton, which, in the intermediate stages of replacement, holds the 

 iron oxide in its cavities." 



A chemical analysis made at the N. P. Pratt laboratory in 

 Atlanta, Georgia, of specimens of the quartzite collected by me 

 is given on page 205 of this paper. 



The ochcr occurs only in the fresh Weisner quartzite and 

 its decay ; and exposures of the fresh rock indicate that it oc- 

 cupies an extensively shattered zone in the formation. It is 

 found in place in the fresh quartzite and in a similar position in 

 the residual clays derived from the decay of* the quartzite. Ex- 

 amples of both occurrences are abundant in the region. 



Associated Ore- Deposits. 



Besides ocher, the district is one of the largest and princi" 

 pal producers of the ores of iron and manganese in the State. 

 In addition to these, some barite has been mined and shipped 

 from the area. The latter mineral, while rather largely distrib- 

 uted over portions of the region, has not proved profitable, for 

 the reason that it is rarely sufficiently concentrated for mining 

 alone, and it is not of sufficient purity to make a desirable 

 grade of marketable baryta. 



The ores are often very closely associated with each 

 other, but recent study of them shows the genesis of the types 

 of ore-deposits to have been quite different. The deposits of 

 yellow ocher are rarely entirely free from some admixture of 

 one or all of the other types of ores mentioned. These are 

 usually present only in small quantity in the ocher, and gen- 

 erally in sufficiently large fragments to admit of nearly com- 

 plete separation from the ocher by the usual process of cleans- 

 ing. 



In many cases manganese oxide, in the form of very finely 

 disseminated grains or powder, is not entirely freed from the 

 refined product, and it is claimed that a faint greenish cast is 

 thereby imparted to the ocher. The deposits of ocher and 

 manganese are frequently in juxtaposition, and the openings 



