E. T. BUMBLE-THE SOILS OF TEXAS 
53 
sive power of the water. The present river channel, as a rule, occupies 
but a small portion of its valley, and all of the principal rivers have 
what are known as first and second bottoms, lying between the channel 
and the uplands, in strips of varying width as the river winds its tortu¬ 
ous way through them. 
* 
The materials of these bottom lands are partly local and partly foreign. 
That is, they are derived not only from the washings brought down from 
the uplands in the immediate vicinity, but also contain the sediments 
taken up by the river in its higher reaches and deposited with these in 
times of flood or overflow. Thus as we follow a long river in its course 
toward the sea we may find a greater and greater mixture in the materials 
of its sediments. 
Coast Prairie Streams.— The streams which lie entirely within the 
Coast Prairies could therefore have an alluvial soil of only those mate¬ 
rials which are found in the immediately adjacent prairies. They are, 
indeed, so lately cut as to be little more than drainage channels. 
Streams of Reynosa Plain.— The rivers of the Reynosa Plain, how¬ 
ever, bring down into the Coast Prairies the sediments they derive from 
the plain in which they have their origin, and their alluvial soils will be 
different from those of the Coast Prairie streams to that extent. 
Rivers of the Grand Prairie.— The rivers of the Grand Prairie, 
with the exception of the Guadalupe, have wide and fertile bottoms and 
are all well timbered. 
The Sabine and Neches have in their upper portions dark waxy soils, 
but after reaching the Tertiary plain a larger mixture of sandy material 
gives rise to dark sandy loams. 
The soil of the Nueces valley is a sandy loam, easily tilled. It is black, 
brown or gray in color, with reddish or yellow loam or clay subsoil. This 
river proves its wanderings through its valley in the past by numerous 
lakes which still exist along it in some portions of its course, especially 
in LaSalle count}'. Its former lake condition is clearly evident in its 
lower course. 
Rivers of the Basin Region. — The Trinity river, while it rises in 
the basin region, does not reach as far west as the “red beds” proper, 
and hence its sediments do not include materials from them. Through 
the Grand and Black Prairies the valley soils are principally a dark loam 
or silt, but through the Tertiary plain the washings from the Black Prai¬ 
ries give a black waxy soil for the bottoms, although in the immediate 
vicinity of the river the soil is lighter and more silty. The vallej^s of 
the lower portion vary from one to five miles in width and are well tim¬ 
bered with oak, ash, etc. 
Red River, the Brazos, and the Colorado all have their origin west of 
the red beds of the Permian, and cross all the more important formations 
