64 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION.. 
of the Lower Tertiary, and the low basin or trough of the Cretaceous 
are the principal exceptions to this uniformity. 
Through all this region of the newer rocks there are alternations of 
nearly level table lands of 500 to 600 feet elevation above tide, bordered 
by red clay and pebbly hills where the table lands break off towards 
the water courses. 
The most recent formations, along the alluvial plains of some of the 
larger rivers and in the vicinity of the Gulf coast in Texas and Louis- 
iana, have almost a dead level surface. 
The topographical features are thus seen to be in great measure, and 
particularly within the hydrographical basin of the Mississippi; the 
result of erosion simply. 
The drainage of the greater part of the cotton -producing area is 
into the Gulf of Mexico, and the Mississippi River the principal chan- 
nel. 
The waters of the Carolinas and Eastern Georgia and Eastern Florida 
find their way into the Atlantic. 
Soils. — The soils which are planted in cotton may be divided into 
two great classes. 
Those of the first class rest directly upon the rocks from which they 
have been derived, or at most have been very little removed from their 
original places ; and hence they are in composition closely related to 
the underlying rocks, and vary from place to place as these vary. 
The soils of the second class have been transported from their place 
of origin, and, as a rule, rest now upon rocks with which they have little 
or no genetic relation. 
Eesulting, as they do, from the commingling of the detritus of widely- 
separated and very different rocks, these soils, over great areas, present 
substantially the same features, irrespective of the particular geological 
formations upon which they have come to rest. 
In general terms, the Paleozoic formations possess soils which have 
resulted from the decay of the rocks of the country, while the newer 
formations have been covered with a mantle of sands, pebbles, and 
loams, which have been brought from greater or less distances, and 
which in a great measure form the soils and subsoils over the entire 
area, with the few exceptions presently to be noticed.* 
The drift soils above named, while similar in composition over large 
areas, are nevertheless in places modified by admixtures with the pro- 
ducts of the disintegration of the underlying Cretaceous and Tertiary 
rocks, and in certain localities these disintegrated rocks themselves 
constitute the soils, as in the black prairie region of Alabama and Mis- 
sissippi, and in some of the Tertiary prairies of these States. 
*It is hardly necessary to say that, with reference to the Drift heds from which they are derived, 
these soils also are sedentary or in place, and the heds of the Drift are, accurately speaking, as much 
rocks as are, for instance, the limestones of the Silurian ago; still, from our point of view, the dis- 
tinction ahovo made has its justification in its convenience. 
