52 Adventures in Scenery 



California and Oregon. It is not strictly speaking a drainage 

 stream, but a channel of escape for the waters from melting 

 snows and rains of a high, rocky and exceedingly rough lava 

 plain. It is thus a subsequent stream. . To the south is the 

 Feather, the Yuba, and the American, all tributary to the 

 Sacramento. These come from the northern Sierras, and 

 traverse deep precipitous canyons. This is a vast, rough, rocky 

 and desolate land. Plumas, Sierra, Nevada, and Placer coun- 

 ties, traversed by the headwaters of these streams, were the 

 scenes of the gold diggers of '49. All this region of north- 

 central California contributes water to the Sacramento. 



The southern and major portion of the Great Valley of 

 California is occupied by the San Joaquin River and its tribu- 



Photo by R. W. Pack, U. S. Geol. Survey 



FIG. 1 6. Boulder of granitic rock in San Joaquin Valley, two miles from 

 mouth of Tacuya Canyon, and moved that distance by running water. 



taries. The San Joaquin rises in the high Sierra southeast of 

 Yosemite National Park. It flows southwestward to the trough 

 of the Great Valley, and thence pools its way northwestward 

 but little above sea level to Suisun Bay, meeting tidal waters 

 from the ocean. The principal tributaries of the San Joaquin 

 north of the main stream descend the Sierra slope in a south- 

 westerly direction parallel to the upper main stream, and join 

 the lower main stream from the east. These are, from north 



