234 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1902. [bull. 213. 
forms a nearly continuous band, 15 miles in length, and generally 
from 1 to 3 miles in width, which occupies the central portion of the 
area. The formation is in contact on the east with the Cartersville 
fault; its base is nowhere shown. It consists chiefly of fine-grained 
vitreous quartzite, although it also contains some beds of fine con- 
glomerate and, probably, considerable beds of siliceous shales. The 
latter, however, are usually concealed by the abundant debris from 
the quartzite beds, which tend to break up into angular fragments 
when exposed to atmospheric conditions. Two subordinate outcrops 
of the quartzite occur near the western margin of the area, being- 
brought to the surface by small faults. The thickness of the forma- 
tion is probably 2,000 or 3,000 feet, and ma}^ be considerably more; 
but it can not be accurately determined because of the intense fold- 
ing which its beds have undergone, and the absence of satisfactory 
exposures. 
West of the quartzite is a narrow belt of deep, red soil, usually 
forming a level valley. This is underlain by the Beaver limestone, 
a formation which rarely appears at the surface, its outcrops being 
almost every where covered with a deep mantle of red clay, in which 
occasional masses of vesicular chert are embedded, along with much 
angular quartzite derived from the adjacent quartzite ridges. The 
few natural exposures of this formation which have been observed, 
together with the results of drilling, indicate that it is a gray crystal- 
line dolomitic limestone, becoming shaly in places, and containing 
occasional masses of chert. It is much more readily soluble than the 
purer blue limestone; and its impurities form an abundant residual 
mantle. In addition to the main belt which it forms along the west- 
ern base of the quartzite ridges, it underlies a broad level valley near 
the western margin of the district extending southward from Grass- 
dale to the line of the Atlantic and Western Railroad. The thickness 
of the Beaver limestone has not been accurately determined; but it 
is probably between 800 and 1,200 feet. With these two formations, 
the Weisner quartzite and the Beaver limestone, a majority of the ore 
deposits in this region are associated. 
Overlying the Beaver limestone is a very great thickness of shales, 
constituting the Rome and Conasauga formations; and above the 
shales is the Knox dolomite. The latter is a massive formation from 
3,000 to 5,000 feet in thickness, composed of gray crystalline dolomite, 
with an abundance of chert. In adjacent regions it is intimately 
associated with extensive deposits of iron-ore; but it is unimportant 
in the present connection. 
The rocks on the opposite side of the Cartersville fault, occupying 
the eastern half of the district, present considerable variety in com- 
position and age. A large area, extending from Stamp Creek south- 
ward across the Etowah River, to the Atlantic and Western Railroad, 
is occupied by the Corbin granite, which is, for the most part, a mas- 
