162 SOUTHWESTERN NEVADA AND EASTERN CALIFORNIA. 
surface in the Panamint Range was developed before the outflow of 
late Pliocene or early Pleistocene basalt. (See p. 202.) 
The crest of the Amargosa Range above 0,000 feet, at a distance of 8 
miles northwest and southeast of Grapevine Peak, is partly covered by 
a sparse growth of pinon and juniper. The largest trees are H feet 
through and from 20 to 25 feet high. The Paleozoic rocks to the west 
of the crest line are bare even above an elevation of (>,000 feet. Some 
grass grows in the higher valleys on the northeastern slopes of the 
range. South of Chloride Cliff the Grapevine Mountains have but 
few springs, and the Largest of these is said to be poisonous and is 
shunned by the Indians. North of Chloride Cliff springs are com- 
paratively abundant. The largest of these, Keane Spring, flows 
about 1,350 gallons per day: the two Willow springs and Daylight 
Spring, from 500 to 1.000 gallons each. The other springs are 
smaller. Hole in the Pock, when full, containing only about 10 
gallons. 
GENERAL GEOLOGY. 
The formations exposed in the Amargosa Range, from the oldest 
to the youngest, are as follows: Prospect Mountain quartzite (?), 
Pogonip lime-tone. Eureka quartzite, Lone Mountain limestone. post- 
Jurassic granite, pre-Tertiary diorite porphyry, biotite andesite, 
earlier rhyolite and contemporaneous basalt, Siebert lake beds, later 
rhyolite and biotite latite, and basalt. 
SEDIMENTARY ROCKS. 
Prospect Mountain quartzite (?). — The Amargosa Range south of 
a line somewhat north of Chloride Cliff is formed of a series of 
quartzite bed- with intercalated schists and marble. The large hill 
group north-northeasi of Lee'- Camp and the small boss-like hills 
northwest of the Big Dune are' of the same formation. This series, 
which includes several thousand feel of sedimentary rocks, is con- 
siderably metamorphosed, the alteration being more evident in the 
schists and the quartzites than in the marble. 
The quartzite- are usually white, pink, or gray in color, although on 
the one hand a cement of specular hematite and on the other much 
clayey matter in the quartzite change the color to black. The normal, 
rather pure quartzose rock is fine to medium grained, and is in many 
places thin bedded. Cross-bedding ami ripple marks are locally 
present. The quartzite passes into conglomerate with well-rounded 
pebbles, which reach a maximum diameter of one-half inch. The 
pebbles are of quartz, of vein or pegmatitic origin, white quartzite, 
black jasperoid, and schist. The development of sericite, particularly 
in the conglomeratic facies of the quartzite, imparts a greenish tinge 
to the rock. On microscopic examination this sericite proves to be 
