CKAWFORD COUNTY. 67 
from beds overlying the clay. These overlying beds have a thick- 
ness of more than 50 feet. 
To obtain this clay it will be necessary to resort to mining. The 
thickness of the material will favor this, and there is an abundance 
of timber in the neighborhood for mining purposes. It is not possible 
at present, however, to foresee the depth to which the soft clays may 
reach before assuming their normal condition as shales. The deposit 
lies within 2h miles of Rudy station, on the St. Louis and San Fran- 
cisco Railroad, and 5 miles from Alma, on the St. Louis, Iron Mountain 
and Southern Railway. This clay is said to have been tested at St. 
Louis and at Fort Smith, but no satisfactory information could be 
gained regarding the parties interested in or making the tests. The 
dark clay has been tested in the laboratory of the Arkansas Geolog- 
ical Survey for loss in burning. The clay burned to a whitish-yellow 
color and the loss due to the burning amounted to 9.71 per cent. 
Van Buren clays. — The most valuable soft clays at and around 
Van Buren are those formed by the disintegration of the Carbonif- 
erous shales. The localities mentioned below are the ones at which 
the deposits appear to be most suitable and most advantageously 
situated for working. 
About 3 miles northeast of Van Buren, in the SW. I NW. \ sec. 16, 
T. 9 N., R. 31 W., close to Hendrick's coal opening, is a light-blue 
clay which burns to a bright yellow. Small test pieces of ware 
said to have been made from this clay show good, sound texture 
and a bright yellow color. No definite information, however, could 
be obtained regarding the parties who made these tests 
The bed varies in thickness from 18 inches to 6 feet. The clay 
was tested for brickmaking purposes at Fort Smith by Pendell & 
Morrison for Mr. L. D. Middleton. Eleven carloads of this clay were 
manufactured into 4,500 bricks, which were used by Mr. Middleton 
to line his limekiln at Fayetteville. The limekiln was kept burning 
for twenty-seven consecutive days. At the end of that time the 
bricks were examined and found in perfect order, though highly 
vitrified. In the manufacture of these bricks Messrs. Pendell & 
Morrison were troubled by the stickiness of the clay, and in order to 
work it in their machine were obliged to mix with it the sandy, 
biown ish-yellow clay used in making their ordinary building brick. 
No definite proportion was observed in the mixture, however, only 
enough of the sandy clay being added to render the material workable. 
Analyses of the clays used in making these bricks are given below. 
Analysis of 'day from SW. \ NW. \ sec. 16, T. 9 N., R. SI W. 
[Brackett & Smith, analysts.] 
Silica (Si0 2 ) 64. 63 
Alumina (A1 2 3 ) 24. 71 
Iron (ferric) oxide (Fe 2 3/ ) ^>- 71 
