The Georgia Bauxite Deposits. — Watson. 29 
constantly grade into each other, and no definite hne can be 
drawn. 
The form of the ore-bodies as well as the structure of the 
material has a direct bearing on the genesis of the deposits. 
The ore-bodies occur in the form of distinct pocket deposits 
of different sizes and usually disconnected, with the vertical 
nearly equal to the horizontal dimensions. Several of the de- 
posits have been entirely exhausted and the pits afford excel- 
lent advantages for observing the size and shape of the ore 
bodies. The largest ones were exhausted after working to a 
depth of about 90 feet. 
The ore-bodies proper are, in every case, where worked, 
surrounded on all sides by white to purple, red and chocolate 
brown, mottled clays and kaolins. The bauxite passes by im- 
perceptible gradations into the inclosing bauxitic clays. The 
ore-bodies and their surrounding bauxitic clays are further 
inclosed in the heavy mantle of highly siliceous residual clays, 
derived from the weathering of the underlying cherty dolo- 
mitic limestone. The contact between the bauxitic and silice- 
ous residual clays is always sharp with no indications of com- 
mingling with or gradation into each other. In no instance 
have fragments of the associated rocks and residual clays or 
foreign material of any character been found in the ore-bodies 
proper or the bauxitic clays inclosing them. The two types 
of clay have evidently had, therefore, a different origin. 
Geologic Position of the Bait. rite. 
The accompanying map indicates a range in the rocks of 
the region from probable Algonkian to Carboniferous in age, 
and includes schists, slates, limestones, shales, sandstones and 
conglomerates. The bauxite deposits are, however, associated 
with those formations which range from the Weisner quarztyte 
(Cambrian) to the Knox dolomyte (Silurian) inclusive. Of 
these formations the Knox dolomyte, which is perhaps more 
properly grouped as part Cambrian and part Silurian, is vastly 
the most important. Because of its unifonpity in lithologic 
character and general absence of fossils from it in this region, 
the entire formation is grouped as Silurian. It has an approx- 
imate thickness of 3,000 to 4,000 feet, and consists of massively 
bedded, partially cr\-stalline, gray siliceous, magnesian lime- 
