KEL.J 
ARKANSAS. 
LOCATION OF CLAYS. 
113 
Only a few of the many known localities are here mentioned. On 
30unt of the geographic relations to the chalk hods, only those places 
nvenient to railway transportation along the St. Louis, Iron Moun- 
n and Southern Railway southwest of Little Rock are spoken of in 
s paper. Should a factory, on account of fuel or for other reasons, 
located west of Little Rock, clays derived from the Carboniferous 
,y shales would have to be used. Of these there is no lack between 
ttle Rock and Fort Smith. 
There are two general classes of clays at Little Rock available for 
tnent manufacture: (1) The Tertiary clays that occur in horizontal 
ds in the southern and southwestern part of the cit}^ and (2) the 
rboniferous clay shales exposed in the railway cuts along the south 
nk of Arkansas River, in the cuts west of the town, and in others 
st of Argenta. 
There are other clays about Little Rock and Argenta, such as the 
ocolate-colored clays along the margins of the river bottoms, and 
pinkish clays forming the high river terraces and used for making 
icks on the north side of the river; but these latter two kinds of 
ys are not available for cement manufacture, partly because they are 
) sandy, but also because they are not homogeneous. An analysis 
the pink clay of Argenta shows it to contain more than 83 per 
it of silica. 
The Carboniferous clay shales are well exposed in the railway cut 
|r the upper bridge, and where the electric power house stands, 
nilar shales may be found here and there over a large part of Pulaski 
unty, within the Carboniferous area. 
COMPOSITION OF CLAYS. 
The following analyses show the composition of the clays. These 
alyses are of representative samples. Most of them contain some 
id, usually quite fine. In those cases in which the percentage of 
id is given the analyses are of the washed clay. 
Analyses of Carboniferous shales from Arkansas. 
lica (Si0 2 ) 
imma (A1 2 3 ) ... 
in oxide (Fe 2 3 ) - 
K'ine (CaO) 
ignesia (MgO) ... 
la (Na 2 0) 
Bull. 243—05- 
1 
2 
3 
4 
5 
6 
7 
53. 30 
62.36 
58.43 
65. 12 
57.12 
55. 36 
51. 30 
23.29 
25.52 
22. 50 
19. 05 
24. 32 
26.96 
24.69 
9.52 
2.16 
8.36 
7.66 
8.21 
5.12 
10. 57 
.36 
.51 
.32 
.34 
.72 
.30 
.32 
1.49 
.29 
1.14 
.31 
1.74 
1.16 
.63 
2.76 
.66 
1.03 
.85 
.53 
1.03 
.72 
69.34 
22.5(1 
1.41 
Trace. 
Trace. 
2.31 
