29± 



MAN AND THE GLACIAL PERIOD. 



Earliest Remains of Man on the Pacific Coast of North 

 America. 



Most interesting evidence concerning the antiquity of 

 man in America, and his relation to the Glacial period, 

 has come from the Pacific coast. During the height of 

 the mining activity in California, from 1850 to I860, 

 numerous reports were rife that human remains had been 

 discovered in the gold-bearing gravel upon the flanks of 

 the Sierra Nevada Mountains. These reports did not 

 attract much scientific attention until they came to relate 

 to the gravel deposits found deeply buried beneath a flow 



Fig. 



94.— Section across Table Mountain, Tuolumne County, California : L, 

 lava ; G, gravel ; 8, slate ; E, old river-bed ; E', present river-bed. 



of lava locally known as the Sonora or Tuolumne Table 

 Mountain. This lava issued from a vent near the summit 

 of the mountain-range, and flowed down the valley of the 

 Stanislaus River for a distance of fifty or sixty miles, 

 burying everything in the valley beneath it, and compel- 

 ling the river to seek another channel. The thickness of 

 the lava averages about one hundred feet, and so long a 

 time has elapsed since the eruption that the softer strata 

 on either side of the valley down which it flowed have 

 been worn away to such an extent that the lava now rises 

 nearly everywhere above the general level, and has become 

 a striking feature in the landscape, stretching for many 

 miles as a flat- topped ridge about half a mile in width, 

 and presenting upon the sides a perpendicular face of 

 solid basalt for a considerable distance near the lower end 

 of the flow. 



