570 NOAH FIELDS DRAKE 
Yuba River, Bear River, North Fork and Middle Fork of Amer- 
ican River, receive almost all their drainage from the north 
side, which would seem to indicate that each of these main 
canyons followed a fault line, and that in addition to the west- 
ward tilting of the mountain mass these separate smaller blocks 
between the canyons tilted to the southward also. 
The regularity of the canyon system and the westward- 
sloping, eroded plain is somewhat more broken to the south of 
Merced River, where the principal rivers, z. e., the San Joaquin, 
the Kings, the Kaweah, and the Kern, have a wide range of 
tributary streams and have carved out more basin-like drainage 
areas. It appears that the southern end of the Sierras has 
existed longer as a mountain range; and also that the Tertiary 
lava flows that spread over northeastern California as far south 
as Merced River did not bury the drainage systems farther to 
the south. Thus it seems that these drainage systems are 
older and naturally more basin-like or collected in larger 
groups. 
The Kern River is the first to break the general westward 
course and flow south for most of its length before turning 
towards the California Valley. The parallelism in the tribu- 
taries of the upper course of the Kern forcibly suggests faulting 
and folding along parallel north and south lines, and probably 
southward tilting also, to guide the streams. 
Cascade region.—The northeast part of California is a table- 
land with cone-shaped peaks here and there rising above the 
general level. Toward the east the flat table-lands are broken 
by ridges extending north and south which usually have a steep 
slope on the east side and a gentle slope on the west side. The 
lava outflows that spread over southeastern Oregon extend in a 
sheet over this area forming the table-land. The cone-shaped 
peaks are lava outpourings, where the lava flows were concen- 
trated at points. Mt. Shasta and Lassen peaks are notable 
examples of volcanic cones on the western side of this area. 
In the northeast corner of this area fault lines are prolonged 
southward from a fault system extended down from southeastern 
