THE LOPOGRAPHY OF ‘CALIFORNIA 571 
Oregon.* Small orographic blocks between these fault lines are 
usually tilted westward and form ridges and basins such as 
Warner Mountains, Alkali Lakes basin, and Goose Lake basin. 
Klamath Mountains —To the west of the lava sheet lies the 
irregular group of mountains known as the Klamath Mountains. 
This region has long been subjected to erosion, and to oscil- 
lations? from archipelago to high land elevations. The outpour- 
ing of lava and accumulations of sedimentary beds on the flanks 
of the granitic core and the irregular tilting, and faulting, have 
produced a complex mountain mass and an area of tortuous 
stream courses. 
The Coast Ranges.—Joining the Klamath Mountains on the 
southwest, and extending southward along the coast are the Coast 
Ranges. The typical part of this system lies west of the Califor- 
nia Valley. This part of the Coast Ranges is composed of 
numerous parallel ranges, ridges, valleys, and canyons which 
extend in almost straight lines along and parallel with the coast. 
The elevations of opposite ranges are usually approximately the 
same. At places the opposite ranges are completely separated, but 
usually they coalesce, only to break again along the same lines. 
Thus along any given line through and parallel with the ranges, a 
topographic feature may disappear but it occurs again after a short 
break. These parallel lines of topographic features show the 
close kinship of the ranges and extensive fault lines and folding 
axes. 
tJ. C. RUSSELL, A Geological Reconnaissance in Southern Oregon. 4th Ann. 
Rept. U. S. Geol. Surv., pp. 436-464. 
2“ At the close of the Taylorville Jurassic there was an upheaval by which the 
Klamath Mountains were outlined.””—J.S. DILLER, Bull. Soc. Am., Vol. IV, p. 224. 
“During the Cretaceous period, especially during that portion represented by the 
Shasta-Chico beds, northern California gradually subsided.... . The Klamath 
Mountains during a part of this time, at least, formed an island.”—J. S. DILLER, Ter- 
tiary Revolution in the Topography of the Pacific Coast. 14th Ann. Rept. U.S. Geol. 
Surv. 1892-3, pp. 23-24. 
“During Miocene times .... the Klamath Mountains were low with gentle 
slopes as compared with those of the present ranges; and the streams flowed down 
their flanks in broad shallow valleys instead of in deep canyons as they do now.”’—JourR. 
GEOL., Vol. II, p. 44; also 14th Ann. Rept. U. S. Geol Surv., p. 423. 
