£. T. BUMBLE-THE SOILS OF TEXAS. 
55 
a much narrower valley than the Brazos, and its alluvial soils in that dis¬ 
tance are therefore less important, although where the valley is wide 
enough for their accumulation they are of excellent quality. 
Below Austin it widens out and the bottoms are heavily timbered with 
cottonwood, elm, ash, walnut, etc. The soils vary from reddish sandy 
loams to chocolate and darker clay loams. 
In its flow through Bastrop and Fayette counties numerous instances 
may be observed of the prevalency of lakes along its course in the earlier 
stages of its growth. This condition may be noted along many of the 
Texas rivers, and indicates that at some period of their history they were 
simply chains of lakes. These were gradually silted up by the overbur¬ 
dened stream, and when in later time the river received fresh erosive 
power, it again cut its channel through them, and now parts of the old 
basins may be seen clearly defined. 
These lake basins and the second bottoms are closely related in many 
ways to the drift soils of the uplands. 
The valleys of the tributaries of these streams will present variations 
of soil under the general principles already stated, in accordance with 
their extent and the variety of materials over and through which 
they pass. The soils vary from black hummock on the smaller streams 
to chocolate loams on the larger. 
We have analyses of the bottom soils of the rivers in various portions 
of their courses. Of the Brazos in the Grand Prairie and Coastal Plains, 
of the Colorado in the Black Prairies and Tertiary, of the Trinity and 
Red River in the Black Prairie, and of the Rio Grande in the Coastal 
Plain. 
Grouping these together, and considering them in connection with the 
rocks over which they flow and from whence their sediments are derived, 
the variations are readily accounted for, not only as among the different 
rivers, but along the course of the same river. 
The length of this article precludes a discussion of these variations at 
this time, but attention is called to the exceptional richness of the soil 
from the Rio Grande valley, No. 59, which Loughridge says “seems to 
be nearer to what many thought to be a 1 perfect soil ’ ” than any other 
in the State. 
Space also forbids the notice of the valleys of the smaller streams, es¬ 
pecially those of the Basin region, which furnish soils of great fertility, 
and they must be left for subsequent presentation. 
The alluvial soil of the Brazos in the Grand Prairie is shown by the 
following analysis of sample of red soil from the second bottom of the 
river at Granbury, Hood county: 
