The Sierra Nevada Range 163 



less plain, one-third of its area, nearly 3,000 square miles, being 

 less than 100 feet above sea level. The west slope is traversed 

 by a number of long rivers. The east slope, which is extremely 

 abrupt and tremendously rugged, is traversed by comparatively 

 short streams. Both slopes are deeply sculptured. The main 

 streams of the wider western slope run through canyons several 

 thousand feet deep. The canyon of the Merced (Yosemite 

 Valley) is 3,000 to 4,000 feet in depth. The Tuolumne and 

 Kern rivers have canyons between 4,000 and 5,000 feet deep. 

 Kings River and its main branches have canyons between 6,000 

 and 8,000 feet in depth. The main canyons of the west slope 

 lie mostly at right angles to the crest line of the range. 



Crest Line an Obstacle to East-West 



Travel 



The crest line of the Sierra Nevada offers a formidable 

 obstacle to east-west travel across the continent. There are 

 few available gaps or notches that afford passes across the high 

 rugged range. Donner Pass, through which the Southern 

 Pacific Railway crosses the crest of the range, has an altitude 

 of 7,000 feet. The annual snowfall as recorded at stations on 

 this part of the Southern Pacific system is 30 to 40 feet, and 

 in some winters as much as 60 feet. Tioga Pass, the route be- 

 tween Mono Lake and Yosemite National Park, has an alti- 

 tude of 9,941 feet. It is rarely free of snow before July. The 

 next pass to the south that is suitable for vehicular traffic is 

 Walker Pass, 180 miles south of Tioga Pass. In all this distance 

 there are only steep and laborious pack trails which climb to 

 altitudes of 11,000 feet, and even over 12,000 feet. 



Barrier Separates Arid Great Plain 



from Central Valley 



The contrast between the regions lying to the east and west 

 of the great Sierra Range is very great. To the east lies the 

 Great Basin of Nevada and Utah. To the west is the Great 

 Valley of California. The Great Basin to the east is a vast 



