148 GUIDEBOOK OF THE WESTERN UNITED STATES. 
From Goffs the railway runs nearly due southwest for many miles 
(see sheet 22, p. 158), descending continuously into one of the great 
interior basins that are characteristic of a large part of southeastern 
California. The slope is covered with a thick mantle of gravel and 
sand, constituting a typical desert plain from which detached moun- 
tain ranges rise abruptly at intervals. These ranges have steep sides, 
are deeply recessed by canyons, and have remarkably ragged or 
pinnacled summits. The plain slopes up toward the mountains an 
is built of the products of their disintegration. The deposits are 
thick, for they have been accumulating for a long time and every rain 
causes a local flood that carries the rock waste farther and farther 
down the slopes and at the same time adds a new supply trom the 
mountain sides. 
There are many instructive illustrations of the relations of these 
desert plains from Needles all the way across southern California, but 
some of the most impressive ones are in the region southwest of Goffs. 
Rain is infrequent in this region, as the average total precipitation is 
considerably less than 6 inches a year. However, much of the rain 
in remarkably heavy showers, or cloudbursts, which quickly 
flood the drainageways with a swiftly flowing body of water suffi- 
ciently powerful to roll large bowlders and to transport a vast amount 
of fine material far down the slope. These floods are exceedingly 
cut by masses of darker rocks. It also | lava caps south of Goffs and of the sam 
e granites. 
mile southeast of Goffs, at the foot of the 
main mountain mass, there is a con 
spicuous butte, capped by black lava | desert surface at a time not very remote. 
ae 
tabular top is due to a thick sheet of lava 
(basalt), which lies on a thick deposit of 
sand and granite bowlders that are under- 
lain by the coarse granite of the main 
mountain slope. This peak is a conspic- 
uous feature for many miles to the west. 
stitutes the higher ridges farther north 
to and beyond the Leiser-Ray mine, 8 
northeast of Goffs, and the Cali- 
the Leiser-Ray mine, is capped by black 
lava (basalt) similar in relations to the 
In the high ridges in the region north 
and west of Vontrigger (see sheet 22) 
the next station on the Barnwell branch, 
10 miles 
thick series of Tertiary igneous rock of 
the same character as that in Black Mesa, 
near Kingman, Ariz. It overlies gran- 
ite along a line that passes a short dis- 
tance west of the California mine. The 
series consists of thick sheets of tuff and 
agglomerate alternatin ith extensive 
with 
flows of light-colored lavas (rhyolite and 
latite). These sheets dip to the east an 
southeast, and the harder beds present 
great steplike cliffs facing the west and 
against the east flank of the Providence 
Mountains. 
