Geology from a Motor Car 387 



and marble, originally shales, sandstones and limestones, which 

 were deposited on sea bottoms as mud, sand, and lime. The 

 rocks have been metamorphosed by heat and pressure, and the 

 beds folded and squeezed together, the remnants of compressed 

 folds or wrinkles of an ancient mountain range that was up- 

 heaved and in turn worn down, and later uplifted as a roof over 

 the injected batholith of the Sierra Range. It is in this series 

 of rocks, and those of the younger Mariposa formation which 

 lie to the west, far to the northwest along the Sierra slope, that 

 the group of gold-bearing quartz veins, the famous Mother 

 Lode, occurs. 



In Merced Canyon, a little above the mouth of Ned Gulch, 

 about 7 miles before reaching El Portal, the river cuts across 

 a series of chert and shale beds (metamorphosed sea-bottom 

 ooze) that are compressed into intricate wrinkles and folds. 

 Polished and scoured in the river gorge these bent and contorted 

 wrinkles in the hard rocks show with astonishing clearness. 



Alternate Route via Big Oak. Flat Road 



And now, here is El Portal, the Gateway, entrance to 

 Yosemite National Park, one of the most marvelous regions 

 of natural scenic grandeur in the world. (Read Chapter XVI, 

 and spend as much time as possible in the Park.) Returning, 

 an alternative route may be chosen. Big Oak Flat road leaves 

 the Valley at El Capitan bridge. It is necessary to check out 

 before departing as the road is a one-way thoroughfare. It has 

 been built at great expense through incomparable rocks, and 

 winds up a well-nigh impossible rock wall, the wall of the 

 Incomparable Yosemite Valley. 



ROUTE F. SAN FRANCISCO, VIA THE GOLD BELT TO 

 THE CREST OF THE SIERRAS. 243 MILES 



Alternate Routes to Sacramento 



Leaving San Francisco via the High Bridge or ferry to 

 Oakland, it is possible to reach Sacramento by different routes. 



