48 
TRANSACTIONS OF THE TEXAS ACADEMY OF SCIENCE. 
In the northern portion these limestones and clays are replaced by more 
sandy material, and these give rise to sandy loams of deep red color such 
as occur near Wichita Falls. 
In the middle division, which contains much limestone, the soils are 
usually dark colored or black marls. The soils near Abilene are of this 
division. 
The upper division is largely composed of sands and clays, and its re¬ 
sidual soils are red or chocolate loams. 
The chocolate loam of the Wichita division is apparently low in phos¬ 
phoric acid, as shown by analysis No. 40. The potash and lime are suffi¬ 
cient, however, for all needs. The same is true of the black loam of the 
Clear Fork division, the analysis of both the soil and subsoil of which is 
given in Nos. 41 and 42. 
40* 
41* 
42* 
Insoluble matter. 
\ 88.46 
f 73.78 
|64.30 
Soluble silica. 
Potash. 
.43 
1.14 
.59 
Soda. 
.14 
.96 
.31 
Lime . 
.74 
4.04 
9.32 
Magnesia . 
Trace. 
1.40 
1.09 
2.06 
1.78 
2.23 
Alumina. 
3.82 
6.51 
5.05 
Phosphoric acid. 
Trace. 
Trace. 
.10 
Sulphuric acid. 
.58 
.15 
4.22 
Carbonic acid . 
2.25 
5.20 
Water. . 
1 .62 
4.52 
4.80 
Organic and volatile. 
3.01 
3.05 
2.69 
100.86 
99.57 
99.90 
* Bulletin 25, Tex. Ag. Ex. Sta., p. 266. 
SOILS OF THE PLATEAUS. 
Cretaceous.— The soils of the Cretaceous plateaus are comparatively 
thin and unimportant, although they furnish a certain amount of pasture 
land. Their service to the underlying materials has already been men¬ 
tioned. 
Llano Estacado. —This great plateau, comprising as it does an area of 
over 30,000 square miles, has soils of most excellent quality. The ma¬ 
terials of which they are composed are the sediments of a great lake, 
which existed here in late Tertiary times, only a single point of the east¬ 
ern shore of which has so far been discovered. This is in the range of 
Cretaceous hills in the southern part of Garza county. 
Four principal kinds of soil are recognized, one of which probably be¬ 
longs to the drift soils. 
The chief soil of the plain is a rich chocolate loam. Next in import- 
