128 SOUTHWESTEKN NEVADA AND EASTERN CALIFORNIA. 
STRUCTURE. 
The Pogonip limestone, as exposed in the Belted Range, lies in a 
monocline which strikes north and dips 20° to 30° VY. next Kawieh 
Valley and 70° W. southwest of Belted Peak. Superimposed upon 
the main fold are a few minor isoclinal folds of similar strike, as well 
as gentle cross folds. This is probably the eastern limb of a broal 
syncline which underlies Kawieh Valley and which has for its west- 
ern limb the eastward-dipping monocline of Quartzite Mountain. 
A number of dip faults of east-west strike cut the Pogonip limestone, 
with a uniform offset of the beds on the north side of the faults to the 
east. The lateral displacement of the largest faults shown on the 
map is LOO feet. 
The Carboniferous rocks are bent into rather open folds, which 
near Oak Spring have north-south axes and to the north of Tippipali 
Spring, as a rule, course northeast and southwest. Small isoclinal. 
folds passing into overthrust faults occur, particularly in the shale. 
The intrusion of the granite considerably disturbed the strata on its 
north side, -while the beds on the other sides were hut little a Heeled. 
The folding was evidently in pail prior to the granite intrusion, in 
part due to it. and in pail later, since the granite in places has a 
sheeting parallel to the bedding plane- of the lime-tone. Since the 
folding of the strata some normal faults have been formed. 
Prior to the extrusion of the earlier rhyolite in the northern part 
of the range the Pogonip limestone formed a mountain range possi- 
bly somewhat lower than the present Belted Range, with it- crest 3 
miles west of the present crest line. In the southern pari of the rangi 
prior to the deposition of the Siebert lake beds the Carboniferous 
rocks had at least a gently accentuated surface, since numerous hill- 
ock- of the older rocks protrude through the younger sediments north 
of Tippipah Spring. The Siebert lake beds at Oak Spring have been 
uplifted without important flexure. After this uplift erosion de- 
veloped a mature mountain surface, which prior to the extrusion of 
the basalt was tilted to the east. The basalt Mow- on the east side of 
the range dip to the east at the rate of 500 feet to the mile, possibly 
indicating that the eastward tilting continued a fter the outflow of the 
basic lava. 
ECONOMIC GEOLOGY. 
OAK SPRING. 
At Oak Spring a number of prospects are being developed. In 
granite U mile- nearly <\\\r south of Oak Spring quartz veins of 
pegmatitic origin, from 1 to 3 feet wide, striking X. 30° E. and clip- 
ping 15° XVY.. have beep staked. The quartz i- white and slightly 
sugary and contains vugs with -mall quartz crystals. Some of it is 
intenselv brecciated, the cracks being 1 stained bv hematite and limon- 
