SOUTHERN PACIFIC LINES 
127 
the Seon type, which predominates in a large part-of the 
Southwes 
The Aes) ‘*M’”’ so conspicuous on the mountain side is painted each 
year by the students of the School of Mines; the ‘““E”’ is placed there 
by high-school students. 
At night a flashing beacon to guide airplanes 
® The Franklin Mountains present a fine succession of strata from pre-Cam- 
brian to Permian, all so bare 
easily studied. They hav 
26 shows the principal features of the range, 
following table: 
and free from talus tha 
e been described by Richardson. 
the various formations are 
The section in Figure 
and the formations are listed in the 
Formations exposed in the Franklin Mountain area 
Thick 
Age Formation ness 
(feet) 
gph fy Limestone, shale, and sandstone. 300 
rmian. eco. imestone 1, 500 
Pennsylvanian. Magdalena. | Limestone. 0-100 
Devonian. ercha. Limestone, dark, impure. 40 
i Fusselman. Lieeices massive, light gua dark. 1,000 
: Montoya. estone, massive, Magnesian 20-400 
Ordovician El P Pateashenins ita Nordic ahias venus eae ae 1, 00+ 
Cambrian. liss. Sandstone, brown and gray, locally conglomeratic at base. 
Rhyolite porphyry, mostly red, with agglomerate at base. 1, 500+ 
Algonkian(?) | Lanoria. Quartzite, light and dark, cut by diabase dikes and sills. 1, 800+ 
3 Miles 
j 
FIGURE 26. he Fran se 
f El Paso, Tex. After Richardson. In, Lanoria 
El Paso limestone; Om, Montoya limestone; 
quartzite; rhp, rhyolite porphyry Bli 
Sf, Fusselman 
to the north; Kem, Comanche series; gr, granite 
Granite similar to the pre-Cambrian 
basement of other regions also under- 
lies the Bliss sandstone, but as some of 
it cuts the Aegektenth and Paleozoic 
strata all has been classed as post- 
Paleozoic. 
The Lanoria quartzite, with its sills 
part of the Millican formation near Van 
Horn. e Paso estone here is 
in its type locality, and the few fossils 
found in it, to a horizon within 100 feet 
of the bottom, are of Lower Ordovician 
age. Locally it lies directly on the pre- 
Cambrian rocks, but at most places it 
is underlain by the Bliss sandstone. 
; Oep 
limestone; Ch, fesastad, mostly Peasitine under! 
; Tap, andesite porphyry; Qb, bolson deposits 
by Devonian and Pennsylvanian 
There are fine exposures of this lime- 
stone on and near the roads at thesouth 
hiatus representing much of late 
Ordovician time. us lime- 
stone, containing a characteristic Pen- 
merus of Niagaran age, represents but 
small dare of Silurian time. It is 1,000 
feet thick and constitutes some of the 
highest rege’ in the Franklin Moun- 
tains. A small wedge of Devonian 
Beate occurs | in the northern portion of of 
Tanga an 
nie otc fossils, The main mass 
