Art. X.] Watson, Yellow Ocher-Dcposits of Georgia. 203 



Over parts of the area it is difficult to state definitely whether 

 the original rock was igneous or sedimentary in origin. The 

 altered sediments include conglomerates, slates, schists, and 

 probably some of the gneisses. Wide variation in composition, 

 and to a less extent structure, characterize the intrusive rocks, 

 ranging from extremely basic rocks of the diabase type to acid 

 granites, with perhaps diorite as the most common type. These 

 igneous masses are no longer composed of massive rocks in 

 structure, but, on account of intense pressure-metamorphism, 

 they are now rendered highly schistose. On account of the 

 absence of fossils in the sedimentaries of this series, and because 

 of the rocks having every appearance of extreme age, Hayes 

 has grouped them as Algonkian (Ocoee) in age. 



The rock-sequence for the Paleozoic formations on the west 

 side of the fault-line, named in descending order, becomes : 



• Silurian, ... 4. Knox dolomite. 



\ 3. Rome and Conasauga sliale. 



Cambrian, . . . -{ 2. Beaver limestone. 



I I. Weisner quartz.ite. 



Of these formations only the Weisner quartzite is ocher- 

 bearing and is of importance in the present connection, hence 

 no description of the other formations will be given in this 

 paper. 



The Weisner Quartzite 



The yellow ocher-deposits of the Cartersville district are 

 limited exclusively to the Weisner quartzite. As shown on the 

 map, the principal area of the quartzite forms a continuous nar- 

 row belt, approximately i 5 miles long and several miles wide, 

 in the central portion of the area mapped. Its eastern limit 

 is the Cartersville fault, which marks the contact of the forma- 

 tion on the east with the rocks of the Ocoee series. Near the 

 middle western margin of the map, faulting has exposed two 

 additional narrow strips or bands of the quartzite, which are 

 marked by the entire absence of ocher. As nearly as can be 

 estimated the thickness of the quartzite in this area does not ex- 

 ceed 2,000 feet. 



