148 SOUTHWESTERN NEVADA AND EASTERN CALIFORNIA. 
sea level) is in the southeast corner of the area. The presence of 
many inlying hills near by indicates that those portions of the old 
mountain mass partially buried by desert gravels possessed an equally 
dissected topography. A majority of the hills are elongated parallel 
to the strike of the Paleozoic rocks. West of the road between Cane 
Spring and Ash Meadows ridges with northeasterly trend predomi- 
nate, and east of the road lie irregular massive groups of hills. The 
hills stop abruptly along a north-south line east of Fortymile Can- 
yon, and prior to the inwash of detrital material this canyon must 
have been a strikingly prominent topographic feature. The hills are 
bare of timber and destitute of springs. 
GENERAL GEOLOGY. 
The formations of these hills, from the oldest to 'the youngest, are 
Prospecl Mountain quartzite, Prospect Mountain limestone," and 
basalt. 
SEDIMENTARY ROCKS. 
Pros pert Mountain quartzite. — Two areas of quartzite, one large 
and the other small, cover 20 square miles near Point of Rocks. The 
formation. ±000 to 3,000 feet thick, underlies the Prospect Mountain 
limestone conformably, with transitional beds between the two. The 
rock, either a quartzite or an indurated sandstone, varies in color 
from gray to purplish red and in grain from fine quartzite to con- 
glomerates, with pebbles one-fourth inch in diameter. The peb- 
bles include white quartzite, red and brown jasperoid, and white, 
smoky, or opalescent quartz of vein or pegmatitie origin. The rocks 
are rather constantly impure and grade through arkoses into minor 
beds of red and green slaty shale. The coarse-grained arkose re- 
sembles granite on first sight. The quartzite is usually considerably 
jointed. 
This rock appears to have been deposited in a comparatively shal- 
low sea. to which much fragmental material was carried. From its 
position, conformably beneath Cambrian limestone, this quartzite is 
undoubtedly to be correlated with the Prospect Mountain quartzite/' 
of lower Cambrian age. 
Prospect Mountain limestone. — The Prospect Mountain limestone 
is the predominant rock of the Specter Range and the Skeleton Hills. 
It is typically light to dark gray, compact, crystalline, and fine 
grained. Some beds have a conchoidal fracture and are almost as com- 
pact and fine grained as lithographic limestone. Pinkish gray vari- 
eties of medium grain also occur, but are rather unusual. Cross-bed- 
ding is observed in places. The beds are typically massive, although 
certain horizons are thin bedded. On weathering the various beds 
" See note, p. 28. 
"Hague, Arnold, Mon. U. S. Geol. Survey, vol. 20, 1802, p. 35. 
