U.S. Highway 40, and now Interstate 80 which replaced it, is the most traveled artery between the Eastern United States and central California. The highway hurdles the sheer, rocky wall of the Sierra Nevada into the valley that stretches to the Golden Gate. From the Great American Basin, it climbs to the granite heights of Donner Pass, traverses the boulder-piled Yuba River bottoms, coasts toboggan-like through forests and along river gorges offering hazy vistas of mountain ranges. It passes the half-ruined mining camps of the gold country and the titanic upheavals of the hydraulic workings. In the western foothills, where orchards appear in forest clearings, it wriggles between rolling evergreen knolls, then strikes across the great Sacramento Valley, and crosses the low Coast Range to San Francisco.