SOUTHERN PACIFIC LINES 35 
County, is, according to Ashley,?> the largest body of cannel coal 
of bituminous rank in the United States. <A large percentage of 
the product is used at Fort Sam Houston in San Antonio. Consider- 
able iron ore is available, and there are many minor mineral deposits 
of value. Helium from bore holes near Amarillo is an important 
product, and potash exists in the northwestern part of the State. 
According to the Texas Almanac, Texas is second only to New York 
in the value of exported materials originating in the State, which in 
1929 had a value of $657,559,600. The total exports, of which about 
two-thirds were shipped from Galveston, were valued at $834,000,000. 
When Texas was admitted to the Union it retained its public lands, 
which, with the exception of large areas reserved for the benefit of 
the State university and schools, have since been disposed of. Many 
square miles were donated to aid railroad construction, and the last 
3,000,000 acres in the “Panhandle” defrayed the cost of the construc- 
tion of the State capitol. A large revenue has come to the State 
university from the discovery and production of petroleum on the 
university lands. Texas public lands were divided into areas of var- 
ious sizes and shapes, some of them in units of 1 square mile, called 
sections and many of them in irregular areas mostly measured in 
varas.”7 
With its great area and variation in elevation, Texas presents many 
differences in climate, ranging from semitropical in the lowlands at 
the south to temperate in the highlands at the west. The rainfall is 
heaviest in the eastern part of the State, where the mean annual pre- 
cipitation exceeds 50 inches. (See pl.1.) There is a gradual diminu- 
tion westward along the Southern Pacific line to 30 inches near the 
longitude of San Antonio, 20 inches near longitude 101°, and from 
10 to 20 inches in most of the western part of the State, some por- 
tions of which are decidedly arid. The rain in eastern Texas comes 
largely from the Gulf of Mexico and falls most abundantly in the 
winter; that in the western part falls mostly in heavy showers in 
summer. Most of the country south of the latitude of San Antonio 
has a mean annual temperature of 70° or more, approaching 75° 
in the southern counties. In the high plains region the mean annual 
temperature is in general less than 60°, and the winters, although 
usually short, are decidedly cold. 
The history of Texas is full of interest. It is believed that the 
first white man to reach the region was Cabeza de Vaca, a member 
of the expedition of Panfilo Narvéez, who sailed from Spain in 1527 
to occupy a royal grant in Florida but, disappointed in its character, 
*° Ashley, G. H., U. S. Geol. Survey | league of 5,000 varas is very nearly 
Bull. 691, p. 251, 1919. 2% miles. A square league is called a 
7 A vara is an old Spanish unit | sitio (4,428.04 acres), and 5 sitios make 
Measuring 33% inches, The old | an hacienda. 
