292 ke. T. Hill—Cross Timbers in Northern Texas. 
The literature hitherto published on the subject conveys but 
vague ideas of the real nature of the Cross Timbers, and usually 
ignores the discussion of their physical features. In fact they 
have always been treated together as one phenomenon, and but 
little intimation has been made of the differences existing 
between them. Neither has much of definite value been pub- 
lished on the surrounding region, for which reason it will be 
necessary to include it in this discussion. 
The Upper Cross Timbers. 
From their greater altitude and their position relative to the 
flow of the rivers, the more western of the Cross Timbers, al- 
though geologicaily lower in the series, is known as the Upper, 
in distinction from the eastern, or Lower. It extends southward 
from the Indian Territory, through the counties of Montague, 
Wise, Jack, Parker, Hood, Erath and Comanche, to near the 
Colorado River. Its eastern border at every point is clearly 
defined, the adjoining prairie region being invariably much 
higher in altitude. The western border is not so sharply 
marked, but it approximately coincides with the 98th meridian 
until near the 32d degree of latitude, when it bends to the 
westward, losing its identity by “thinning out,” so that the 
boundary between the wooded and prairie region is not always 
‘apparent. The surface soil usually consists of an exceedingly 
fine-grained siliceous sand, which is the detritus of the under- 
lying strata. This sand is utterly untenacious, except when 
wet, and is readily distributed by the high winds over the sur- 
face so as to effectually conceal the underlying strata. A small 
amount of red clay from a neighboring stratum gives to the 
sand, when mixed with it, a dirt-yellow color. Although des- 
titute of turf, the surface is covered with a thick growth of 
stunted trees and bushes, consisting mainly of the post oak 
(Quercus obtusiloba) and the black jack (Q. nigra), accom- 
panied by elms and hackberries, and many annuals and peren- 
nials that accommodate their appearance to the time of rainfall. 
This flora is nearly constant throughout the entire extent of 
the Upper Cross Timbers, and most of its species also occur in 
the lower member. The character of the soil, as above de- 
scribed, is also constant along the eastern edge, but is varied 
along the western half of the timbers by the presence of a 
erumbling, fine-pebble conglomerate. 
2 
The Lower Cross Timbers. 
‘The lower Cross Timbers are located about fifty miles east 
of the upper belt, and extend in a direction approximately 
parallel to it. They are separated their entire length by a 
prairie region, utterly destitute of timber. The western mar- 
