96 GUIDEBOOK OF THE WESTERN UNITED STATES 
Tertiary age, but on its west slope 1% miles northeast of the station 
there is a small exposure of limestone of Comanche age dipping west, 
with relations shown in Figure 14. Near by, at the foot of the hill, is 
Kokernot Spring, or Charco de Alsate, on the Chihuahua trail from 
Fort Stockton to Presidio and the military road from Pefia Colorada 
to Fort Davis. It was at this spring in the early days that a caravan 
of 40 freight wagons was surrounded by Apache Indians with the ex- 
pectation that it would be easy prey. Fortunately one man was able 
to slip away and reach the United States Army post at Presidio, 
100 miles distant, whence forces were sent to the rescue. 
A water hole which the railroad crosses on a bridge just west of 
Alpine is thought to be the place where Juan de Mendoza camped on 
2 Miles 
FIGURE 14.—Secti he Alpine Basin just Alpine, Te 
agglomerate; Kc, limestone (Comanche) , 
1, Lava (Tertiary); ag, 
January 4, 1684, on his notable exploration from the vicinity of El 
Paso across western Texas to Rio Concho. He was sent by Governor 
well into Tertiary time. 
from far below thi 
cracks and 
They came The lavas in this region are mostly 
of the varieties known as rhyolite and 
trachyte, with a small amount of basalt, 
fragmental material 
also cow out of the numerous vents. 
This consists of agglomerate or breccia 
(made up mostly of coarse fragments 
of lava) and tuff (finer-grained ash and 
cinders), and there was also some fine- 
voleanic ash. Most of this 
ejected matter piled up in sheets as it 
fell, but in some water had a 
part in its distribution, ea from some 
of the vents there 
tal material and were in places 
buried beneath later eruptions of bree- 
cia, tuff, and ash 
par- | vidual flows. 
canic activity the configuration of the 
region was probably much smoother 
than it is now, for the old surface on 
which the volcanic deposits lie appears 
to be smooth at most localities. Sev- 
eral ridges of older rocks protruded, 
however, some of which were not 
covered by volcanic materials. 
y w. 
uplift, the vol- 
canic rocks have been recut laying 
bare the underlying older rocks. 
