316 



Adventures in Scenery 



been buried were uncovered. The lavas, however, were hard 

 and resistant to the wearing action of streams. New river 

 courses were established down the slopes of the later formed 

 mountains. These streams disregarded the former valleys, 

 which had been filled with lava. Table Mountain in Tuolumne 

 County is a tremendous example of a valley that was filled with 

 lava, which in turn became hard resistant rock. Because it was 

 hard streams cut channels around it. These channels became 



Courtesy U. S. Bureau of Mines 

 FIG. 92. Gold nuggets from Tuolumne River. (Actual size.) 



deep valleys because the slope gave to the streams great eroding 

 power. Finally Table Mountain came to be the top of a great 

 plateau underneath which were gravels that were deposited on 

 the bottom of the earlier stream, and in the gravel was sec- 

 ondary gold from veins higher up the slope. These gravels are 

 now high up in the hill or ridge of the great plateau, far above 

 the bottom of the valleys that have been eroded alongside. So 

 what had been stream beds or valley bottoms stand now high on 

 hills and ridges. Into such hillsides the lure of gold has led man 



