77?^^ Georgia Bauxite Deposits. — IVatsoii. 4-^ 
trate the chemical chang"cs incident upon the weathering of this 
rock. In his description of tlie niag-nesian hmestone professor 
Kussell makes the following statement': "The original rock 
in this instance was a grayish-white dolomyte t_\'pical of its 
class over a large area in the southern part of the Great Ap- 
palachian valley, while the clay left hv its decay is a fair sample 
of the red soil of the South."* 
Constituents. ^ \"''^^1\ Residual 
Dolomyte Clay 
Si02 3.24 55.42 
Al2n3 0.17 22.17 
Fe203 0.17 8.30 
FeO 0.06 trace 
MgO 20.84 1.45 
CaO 29.58 0.15 
NaoO 0.17 
KoO 2.32 
H2Oatll0°C 1 2.10 
H2O above 110^ C / 7.76 
• COo : 
Total 99.9(1 99.84 
As indicated hy the above analysis the residual ])roduct 
clearly represents a highly siliceous ferruginous clay, in which 
only a trace of the original more soluble calcium and magnesium 
salts is retained. 
This Knox dolomyte, is underlaid, however, evervwhere in 
the district by several thousand feet of calcareous clay or alum- 
inous shales, which, as shown' bv the analyses below, contain 
20 to 30 per cent, of alitmina. in addition to the other constitu- 
ents commonly found in the deposits, such as silica, titanic and 
iron oxides. 
The following analyses indicate the general composition of 
the midflle Cambrian shales of the bauxite region : 
I. II. 
SiOs 55.02 52.82 
AI2O3 21.02 26.17 
Fes^'a 5.00 9.46 
FeO 1.54 
MjjO 2.32 1.08 
CaO 1.60 trace 
*Ibid, p. 24.. 
I. Middle Cambrian shale. Cposa valley, near Blaine, Cheroket County 
Alabama. Dr. H. N. Stokbs, analyst. Bulletin No. 10<S U. S. Geol. Survey 
1900. p. 28.-'.. 
II. Oostanaula shales about two miles northwest of Cartersville, Bartow 
County, Georgia. J. W. Spe.ncer, Pal«{Ozuic Group, Geol. Survey of Georgia, 
1893. p. 285. 
