1() A GAZETTEER OF TEXAS. [bull. 224. 
TOPOGRAPHY AND DRAINAGE. 
The eastern two-thirds of the State is a plain, mainly with a rolling 
surface, sloping gently toward the southeast, and ranging in altitude 
from 2,000 feet to sea level. Between the one hundredth and one hun- 
dred and first meridians the land rises, in some places quite abruptly, 
to a plateau known as the Llano Estacado. This plateau, which has an 
altitude ranging from 2,500 feet in the south to more than 4,000 feet 
in the north, has an extremely level surface, upon which are few flow- 
ing streams. It extends westward nearly to Pecos River, and is suc- 
ceeded beyond that stream by a region consisting of an alternation of 
irregular mountain groups and ranges alternating with broad, desert 
valleys, most of which are without outlet. 
The average altitude of the State is 1,700 feet. The area is dis- 
tributed in altitude as follows: 
Square miles. 
to 100 feet 23, 000 
100 to 500 feet 58, 400 
500 to 1,000 feet 39, 380 
1,000 to 1,500 feet 19, 800 
1,500 to 2,000 feet . 22, 200 
2,000 to 3,000 feet 44, 100 
3,000 to 4,000 feet 26, 100 
4,000 to 5,000 feet 29, 800 
5,000 to 6,000 feet _\ . . . 2, 000 
Over 6,000 feet 400 
Of the entire area 45 per cent is below 1,000 feet; 16 per cent 
between 1,000 and 2,000 feet; 17 per cent between 2,000 and 3,000 
feet, while 22 per cent is above 3,000 feet. 
The eastern part of the State is well watered by numerous streams, 
the principal of which are the Sabine, Neches, Trinity, Brazos, Colo- 
rado, Guadalupe, Nueces, and upon the Mexican boundary the Rio 
Grande. Upon the north of the State flows Red River, which heads 
in the Staked Plains, while across the Panhandle flows the Canadian 
River, a branch of the Arkansas. The western part of the State is 
scantily watered by the Rio Grande and its main branch, the Pecos. 
Most of the smaller streams flowing into these two rivers are dry 
during the greater part of the year. 
CLIMATE. 
, Stretching over 13 degrees of longitude and 10^ degrees of latitude 
the State presents great variations in climate, ranging from that of the 
Tropics to that of the Temperate Zone and from excessive rainfall to 
ver}^ arid conditions. The mean annual temperature in southern Texas 
is about 75 degrees, from which it diminishes to 55 degrees in the 
Panhandle of northern Texas. The rainfall is heaviest in the eastern 
part of the State, where it exceeds 50 inches annually, and diminishes 
