SOUTHERN PACIFIC LINES 141 
finally reaching the base of the Sarten sandstone (Cretaceous). 
There are several faults at the south end of the ridge.*® 
In the southeast end of Fluorite Ridge a large amount of the 
mineral fluorite has been mined. It consists of calcium fluoride and is 
of bright-green color, crystalline structure, and glassy aspect. It is 
used extensively in steel making. The mineral occurs in several 
steeply dipping veins, mostly i in the porphyry; these varied from a 
few inches to 12 feet or more in thickness with a general range in the 
workings from 2 to 5 feet. Much of the fluorite was more than 90 
r For several years this material found a ready market 
at Pueblo, Colo., and other places, and the annual production aver- 
aged about 5,000 tons, but cheaper sources of supply were found and 
the workings are now abandoned.’ 
The Cooks Range, lying north of Fluorite Ridge and a very con- 
spicuous feature from Deming, is an irregular dome due to a great 
¢ 
oO 
p = 
Wanye - fos 
As |. 
ah gies oe ey Se = 
\ ey ep Peo Sane =, 0 
= ais: as Poaey 
aS Su is aX WS 52 
“oN , a2, j 
ou 
oo t , 3000 Feet 
F1GURE 32.—Section across Fluorite Ridge, N. Mex. Tag, Agglomerate; Ks, Sarten sandstone; 1, 
Lobo formation; Clv, Lake Valley limestone; Om, Montoya limestone overlain in part by lime- 
stone of undetermined age; Oe, El Paso limestone’ €b, Bliss sandstone, gr, granite and diorite; p, 
porphyry; b, diabase dike 
central intrusion of porphyry which brings into view a floor of pre- 
Cambrian granite and the succession of Bliss sandstone, El Paso, 
‘Red granite and diorite (pre-| largely of Sarten sandstone penetrated 
Cambrian) are exposed in the lower | b hyry and overlain by Tertiary 
southern slopes and also a breccia of | agglomerate. A small exposure of 
mica schist fragments. The Bliss ane granite in the locality indicates one 
stone is overlain by a regular successi faulting or bade for in places 
of strata to and including the eve Sarten sandstone lies directly on 
portion of the Lake Valley limestone. | granite. Goat Rides, a short distance 
Some of the beds are greatly squeezed, | to the west, is an elongated dome with 
notably the El Paso limestone, _— axis trending northwest that exposes 
Sarten sandstone. The 
rock at the east end of the range have | in part of the area, and granite appears 
undoubtedly replaced limestone, prob- | on the northwestern slope of the ridge. 
ably of both Lake Valley and Montoya | The Pony Hills, a small group of knobs 
age. A profound fault that extends | just north of Fluorite Ridge, consist of 
along the east side of the ridge appears | irregular outcrops of granite and 
to lift porphyry, although it is possible | Sarten sandstone in prin Benge 
t his igneous rock was intruded | owing either to overlap or 
after the faulting, and there is some 7 Darton, N. H., and Burchard, E. F., 
i ear 
slopes on the east side of the ridge. 545. 1911, 
The west end of Fluorite Ridge consists 
