202 THE CLAYS OF ARKANSAS. 
to the committee that the clay shales in the vicinity of the city were 
well adapted to the manufacture of paving bricks. This opinion was 
supported by analyses made by the State Geological Survey, and 
later by practical tests made by brick manufacturers. 
The following letter was addressed to the paving committee after 
the examination: 
Dear Sir: At the request of the paving committee of your board of commerce I 
have made a cursory examination of the material in the immediate vicinity of Fort 
Smith with a view to ascertaining its availability for the manufacture of paving brick. 
The clays and clay shales about Fort Smith available for the manufacture of bricks, 
tiles, pottery, etc., belong to two distinct geologic ages. To the newer division 
belong the yellowish, reddish, and dove-colored loams, clays, and sandy clays which 
underlie almost all the plain upon which the city of Fort Smith is built. 
The bricks now made at Fort Smith are made either from the uppermost of these 
beds or from a mixture of this and the one just beneath it, as is now practiced at Pen- 
die & Morrison's brickyards. 
In some of the deeper hollows there are later deposits of chocolate-colored clay 
which by the admixture of organic matter has been changed to a deep black soil at 
the surface. An analysis of a similar clay from near Dardanelle is given below. 
The other class of material which is available for the manufacture of pottery, bricks, 
tiles, etc., is a clay shale belonging to the Carboniferous series of rocks. These 
shales are interstratified with sandstones and other rocks of the coal measures and are 
probably widely distributed through Sebastian and adjoining counties. The clay 
said to have been taken from Crawford County to the brickyards of Pendle & Morri- 
son for testing is simply a disintegrated clay shale. The light-colored and mottled 
clays overlying the sandstones of Harding & Boucher's quarry, a couple of miles south 
of Fort Smith, are also disintegrated clay shales. An extensive exposure of such 
shales, however, occurs much nearer the city. On the public road leading south 
from Fort Smith and about 600 feet south of the crest of what is popularly known as 
Nigger Hill the ditches beside the road have exposed a thickness of 10 or 15 feet of 
friable clay shales. This shale bed is capped by a stratum of sandstone, but its base 
is not exposed. It will be found to extend around the hills on both sides of the road, 
and there can be no question of its great abundance both at the locality mentioned 
and in the continuation of the bed around the sides of the hills. 
Following is an analysis of the clay shale from Nigger Hill, in the vicinity of Fort 
Smith: 
Analysis of clay shale from Nigger Hill. 
[Specimen dried at 110°-115° C. Brackett & Smith, analysts.] 
Silica (Si0 2 ) 58. 43 
Alumina (A1 2 3 ) 22. 50 
Ferric oxide (Fe 2 3 ) 8. 36 
Lime (CaO) 32 
Magnesia (MgO) .1-14 
Potash (K*0). : 2. 18 
Soda (Na 2 6) s 1. 03 
Sulphur (S) 16 
Loss on ignition 6. 87 
100. 99 
Sand in air-dried specimen 25. 72 
Water at 110°-115° C 3. 37 
