TENNESSEE MARBLES." 
By Arthur Keith. 
STRATIGRAPHY. 
Beds of workable marble are found in a belt in the center of the 
valley of East Tennessee, extending nearly across the State. The 
general belt is composed of a number of nearly parallel bands or lines j 
of outcrop of the marble formation. They were brought into their 
present attitudes during the folding of the strata of that region, and 
bear their present relations to the surface in accordance with the 
progress of erosion of the rock materials. The exposures of the mar- 
ble are to be seen in the following counties, beginning at the north- 
east: Hawkins, Hancock, Hamblen, Grainger, Claiborne, Union, Knox, 
Sevier, Blount, Roane, Loudon, Monroe, and McMinn. 
All of the marble is found in the strata of Silurian age, much the 
greater part of it in the Chickamauga limestone. On account of the 
prominence and extent of the marble in that formation near Ilolston 
River, it has been called "Ilolston" marble in the folios of the United 
States Geological Survey. A considerable development of marble is 
also seen in the lower portion of the Sevier shale in Sevier, Knox, 
Blount, and Monroe counties. Practically all the quarrying has been 
done in the Chickamauga limestone, although in Knox and Blount 
counties some of the higher beds have also been used to a small extent. 
In the lower part of the Chickamauga formation are many beds of 
more or less coarsely crystalline marble. These do not appear, 
except in a most local way, northwest of the S3mclinal fold from 
which Clinch Mountain rises. In that syncline and southward, how- 
ever, marble is usually well developed in all the areas of the forma- 
mation. It is from 600 to 650 feet thick near Clinch Mountain and 
thins in all directions from that area. Its average thickness is 300 
to 400 feet, where well developed. The position of the marble beds 
in the limestone varies much from place to place. Usually there is a 
considerable thickness of blue and gray limestone below the marble; 
north of Clinch Mountain, however, this is not the case, as the marble 
beds are thicker and rest directly upon the Knox dolomite. The 
same condition was observed on the south side of Black Oak Ridge. 
a A resume of material presented in folios of the Geologic Atlas of the United States. 
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