e 
SOUTHERN PACIFIC LINES 57 
plant in many parts of the region to the west across Texas, New Mex- 
ico, Arizona, and southern California. Its beans are an important 
source of food for grazing animals and they are used for flour by the 
Indians and Mexicans. The wood is a most useful fuel, and the plant 
yields a valuable gum; a decoction of the bark is esteemed by the 
Mexicans as a laxative. 
The high percentage of gypsum in the Yegua strata makes the 
soil unfavorable for many crops and the water unsuitable for stock, so 
that the outcrop area of the formation is rather thinly settled. About 
2} miles east of Waelder the railroad deflects to the north and follows 
the divide between Sandy and Copperas Creeks, crossing the rather 
ill-defined contact between Yegua and Cook Mountain strata 
about 1 mile east of Waelder. 
Sandstone of the Cook Mountain formation makes a ridge of moder- 
ate prominence that extends far to the north and south of the railroad. 
he formation includes sands and glauconitic marls 
Waelder, and clays,** some of them lignitic but for the most 
xe. Bae feel part of marine origin. The higher beds are locally 
opulation 1,048. fe . 
ew Orleans 495miles. fossiliferous, and many of the species were early 
correlated with those of the sands of the Claiborne 
of Alabama. The glauconitic beds of the Cook Mountain formation 
are highly colored by the oxidation of the iron, and in many places the 
formation carries an appreciable content of phosphate, which serves 
as a fertilizer. The Cook Mountain greensand soil is highly produc- 
tive, and cotton, corn, and garden truck are successfully grown along 
its outcrop. The basal member of the Cook Mountain is the Sparta 
sand, probably nonmarine, carrying less iron than the higher beds. 
Its outcrop zone, from 1 to 2 miles wide, is crossed by the railroad on 
the down grade to the valley of Bee Branch, 4 miles west of Waelder. 
The vegetation varies with the formation; the mesquite here is not so 
large nor so numerous as in the Yegua area, but the oaks are very 
much more in evidence, especially on the lower, more sandy beds. 
On leaving the outcrop zone of the Sparta sand member of the 
Cook Mountain formation the railroad bends considerably to the 
south, and for the next 5 miles, or nearly to Harwood, it crosses the 
Mount Selman outcrop diagonally. The strata dip to the west- 
northwest at a low angle. In a general way the Mount Selman beds 
resemble the Cook Mountain formation, consisting of glauconitic 
sands, marls, and clays, but they contain a greater number of indu- 
rated, irony beds, so that the hills and ridges are higher and the soil 
amore intensered. The soil is productive and well adapted to truck 
farming, and a large part of the 25,000 acres planted in tomatoes in 
%8 The mineral glauconite, also called | alumina deposited in the sea through 
d, is a silicate of iron sil Goguane vee cuamaus wpkama: : 
152109°—33——5 
