140 THE CLAYS OF ARKANSAS. 
In the S. \ SE. \ sec. 2, T. 12 S., R. 18 W., on a small stream 
called Sandy Branch, is an exposure of material that has received 
considerable attention. It has the appearance of being a very- 
sandy, compact, nonplastic, whitish cream-colored clay. It has 
usually been regarded as a fire clay, but the percentage of water of 
crystallization contained in the material when freed from sand 
shows it to be a kind of kaolin. 
This bed is exposed inconspicuously at three or four places on 
Sandy Branch, at the base of the hills that form the western limit 
of the immediate valley of Ouachita River. Most of the outcrop 
is concealed by debris that has fallen down from the hills above, but 
it has been opened sufficiently to show its relation to the overlying 
beds and to expose a thickness down to the water of Sandy Branch 
of 12 feet, but without discovering the total thickness of the deposit. 
The geology of the region leads to the 
) belief that this material lies at the base 
Igg^jL of the hills up and down Sandy Branch 
'<«an^^^ from the point referred to and on both sides 
of the stream, probably forming an out- 
r^z^-^n g crop several miles long. A hill nearly 100 
feet high rises to the west of the outcrop, 
but in all probability places may be found 
at which there is no 
' — considerable covering 
Fig. 13.— Section on Sandy Branch, near Ouachita River, Ouachita £q the bed At the 
County, a, Plastic clay; b, brown lignite; c, sandy kaolin. 
exposure referred to a 
bed of brown lignite a about 3 feet thick overlies the clay, and above 
this is a bed of plastic clay, the thickness of which is not exposed. 
Fig. 13 is a section at this locality. 
The following is an analysis made by the St. Louis Sampling and 
Testing Works of a sample said to have been taken from this kaolin 
bed. It was kindly furnished by Dr. A. S. Garnett, of Hot Springs, 
who had the analysis made in August, 1889: 
Analysis of kaolin from Sandy Branch. 
Silica (Si0 2 ) 06. 25 
Alumina ( A1 2 3 ) 25. 35 
Sesquioxide of iron ( Fe 2 3 ) • 22 
Lime (CaO) 20 
Magnesia (MgO) Trace. 
Alkalies 84 
Water and loss 7. 32 
100. 24 
a As a rule this lignite is considerably thinner on the. outcrop than inside. 
