Geolofiij of Eastern California. — Fairbanks. 71 
paratively short detrital slope on the west, while on the east 
and north it is eight to twelve miles long. 
Excellent examples of the detrital slope are found in Coso 
valley which has no level bottom. Sloping planes of various 
degrees of inclination surround the whole valley, which is 
perhaps fifteen miles long and eight miles wide. All unite at 
its eastern side where a canon has been cut through the Argus 
range, allowing the detrital laden torrents to spread out over 
the upper end of the Panamint valley. That portion of the 
valley has an elevation of about 1.500 feet, while the upper 
stretches of the detrital slope in Coso valley reach an eleva- 
tion of nearly 6,000 feet. 
The debris accumulated along the eastern slope of the Si- 
erra Nevadas seldom exceeds rive miles in width except in 
Salt Wells valley. Owen's valley is nearly 100 miles long and 
does not average more than ten miles in width, and it is prob- 
able that an enormous mass of gravel many thousand feet 
thick forms the bed of the valley beneath the more recent ac- 
cumulations of sand. 
Indications of great changes of level in recent times are not 
wanting in many places. Near the summit of the Argus range 
at an elevation of 7,500 feet there is a small patch of con- 
glomerate with boulders, several of which are live feet in di- 
ameter, of different varieties of granite. This part of the 
range is formed of the rocks of the nietamorphic series. 
Stratilied gravels covering many square miles lie along the 
western slope of the mountains between the Panamint and 
Mesquite valleys. These beds have been deeply cut by the 
modern canons and being unconsolidated supply a vast 
amount of detritus for the occasional cloudbursts. These 
gravels reach an elevation of 6,000 feet, extending nearly to 
the summit of the range. 
Igneous Rocks. 
The igneous rocks will be described under two heads. (1) 
granitic. (2) volcanic. It will be limited to the manner of oc- 
currence and genera] macroscopical character. 
( ! ). Granitic Bocks. The granitic rocks form the cresl 
and eastern slope of the Sierra Xevadas as far north ;is Pine 
creek, a tributary id' the upper Owen's river. From that poinl 
past .Mono lake the granite is largely replaced by highly met- 
