142 THE CLAYS OF ARKANSAS. 
This shows that this material is simply a sandy kaolin and not 
an ordinary clay, in the chemical sense of that term. 
After the sand is removed by washing it is available for the manu- 
facture of pottery and also as a refractory material. As a fire 
clay it will be spoken of elsewhere in this report. The quantity of 
this kaolin in the vicinity of the locality described above seems to 
be very large. Mr. Winslow observed the following section in the 
NE. I SW. I sec. 2, T. 12 S., R. 18 W., under a bluff very like that 
observed by the writer on Sandy Branch: 
Section in sec. 2, T. 12 S., R. IS W. 
Ft. in. 
Sand and clay 6 
Decomposed lignite 8 
Gray clay 1 6 
Decomposed lignite 1 6 
Sandy kaolin 12-15 
At this place also the full thickness of the bed is not seen. 
It is reported from several places in sec. 36, T. 11 S., R. 18 W. 
At one point the former exposure is said to have recently been con- 
cealed by a landslide; at another place it is said to be 4 feet thick, 
and has been used for whitewash. 
In the SW. I NW. J sec. 36, T. 11 S., R. 18 W., at the house of Jack 
McKinzie, the following section was passed through in digging a 
well: 
Section in well in sec. 36, T. 11 S., R. IS W. 
Feet. 
Clay 2 
Lignite 2\ 
Gray clay with sand 3+ 
There are thin beds of pottery clay on a branch of Wolf Creek at 
the mouth of a lignite drift in the NE. J NW. \ sec. 14, T. 12 S., R. 
18 W. These beds are only a few inches thick, and therefore too thin 
to be of any practical value. Inside the drift they are only 6 or 8 
inches thick. It is possible that these beds may be thick enough in 
this neighborhood to render them valuable. The clay itself is of fair 
quality, as the following analysis of it shows : 
Analysis oj clay from NE. I NW. \ sec. 14, T. 12 S., R. IS W. 
[Sample dried at 110°-115° C. Brackett & Smith, analysts.] 
Silica (Si0 2 ) 79.42 
Alumina (A1 2 3 ) 13. 35 
Ferric oxide (Fe 2 3 ) 2. 17 
Lime (CaO) Trace. 
Magnesia (MgO)..l 
Potash (K 2 0) .... | Trace. 
Soda(Na 2 0) J 
Loss on ignition (H 2 0) 5. 38 
100. 32 
Sand in air-dried specimen 9. 48 
Water at 110°-115° G 3. 72 
