102 GUIDEBOOK OF THE WESTERN UNITED STATES 
The trail from San Antonio to El Paso on leaving Fort Davis swung 
around the foot of Livermore Peak north of Valentine and crossed 
Lobo Flat to the Van Horn wells, which were near the present Lobo 
siding. (Turn to sheet 16.) 
From Chispa siding there formerly was a branch railroad (of which 
the grade is still visible) that passed through a gap (Chispa Summit) 
between the north end of the Tierra Vieja Mountains 
and the south end of the Van Horn Mountains and 
thence turned southward to the San Carlos coal mine. 
This mine yielded considerable coal, but apparently 
the enterprise could not compete with the producers 
of petroleum fuel. In the gap through which this branch railroad 
Chispa, 
Population 18,* 
New Orleans 1,043 
miles. 
Tierra Vieya Mts 
Chispa Summit 
t tie (gap) 
ee) 
Nerreadts! scale : 
° 2 Miles 
SS | 
Vartical scale 
° 1.000 2,000 Feet 
Bacal A i 5. i. = 
Ficure 15.—Profile of the northern part of the fest Vieja ete south of Chispa siding, Tex. 
Tertiary lava; Tt, Tertiary tuff; Ks, Upper Cretaceous shale; Kef, Eagle Ford formation 
(Upper Cretaceous); Kg, Georgetown jirisetone penis er Cretaceous) 
passed there is an interesting thumb-shaped plug of volcanic rock, 
plainly visible from Chispa siding and points beyond, which is the 
remains of a volcanic vent, probably of Tertiary age. The general 
relations in the mountain as viewed from Chispa are shown in Fig- 
ure 15. The hard beds give rise to tables and cliffs and the softer 
strata to the intervening slopes. North of Chispais Chispa Mountain, 
a sharp peak of volcanic rocks. 
The Van Horn Mountains,” which lie north of the gap west of 
Chispa siding, cause a long northward deflection of the railroad. 
2 The Van Horn Mountains present 
gap west of Chispa, there is a strong 
a wide area of strata of Lower Creta- | downward pitch and downfaulting of a 
ceous (Comanche) age, overlain in the | block consisting of a thick succession 
high central part and the northeast end | of the Upper Cretaceous rocks that 
make up the north end of the Tierra 
thick, with a coarser conglomerate at 
the base, a thick mass of Cox sandstone 
above, and then representatives of the 
Finlay li ( imestones of the 
Fredericksburg group. In ths eastern 
part of the range the strata lie nearly 
horizontal, with a maple outcrop of 
the harder beds. At its —— end 
limestones of Permian age the 
surface in the high uplift Sse 
Horn region. To the south, near the 
| Vieja Mountains 
The main rides of the Van Horn 
Mountains is an anticline of consider- 
Crossed by a fault 
with drop on the north 
side, 8 ae aairtdxwent ‘ok Chispa, the 
anticline rises to the north so that the 
limestone of Permian age finally ap- 
, overlapped by Trinity beds in 
= north end of the range. The Fin- 
i in this range consists of 
shaset 400 feet of gray earthy limestone 
. E 
