208 



UNITED 



mining, in which the gravel is attacked by powerful jets of water^ is 



agricultnrii 



chiefly 



parts 



rivers prohibit the washing of silt and sand and other mining debris 

 into the streams. The general character of these old hydraulic work- 

 ings can be well seen from the railroad. 



The historically important discovery of gold in California was made 

 in January, 1848, at John Sutter's mill on South Fork of American 

 River near Coloma^ a point only 10 or 15 miles southeast of the town 



the train will soon pass. From 1850 to 



Auburn, thronsh which 



from the gravels, and the 1 

 more than S65.000.0G0. in 



some 



but a production of about ^50,000,000 a year, chiefly from placer 

 mines, was maintained up to 1861. 



At first the gold was won chiefly from the gravels along the present 



streams. 



first sot possession of the rich bars on Ameri 



rivers 



to 55,000 a day- 



made at times from 



unus 



tainly far less than that of men 



income of the great 



common 



nels with their lava caps now lie on the 

 ridges. (See fig. 18.) 



Of interest in connection with the Ter- 

 tiary river gravek is the story of the 

 Calaveras skull. For a time this ?kxill 

 attracted much attention not only from 

 people in California, but from scientific 



that man had been in existence in North 

 America very much longer than had been 

 supposed. Strange to say, the skull is 

 of a higher type than skulls which, al- 

 though known to antedate historic times, 

 are known also to be much younger than 

 the Tertiary. Although Prof. J . D . A\Tiit- 



Lava 



Tertiary 

 auriferous gravel 



Lava 



riGUBB 18.-Dkgram showing the present relation of the Tertiary auriferous gravels to bedrock and 



lavas, also the position of the gravel remnants high on the ridge summits. 



men the world over. 



reported 



have been found in 1866, near the town of 

 Angels, Calaveras County, at a deptli of 

 130 feet, in Tertiar\' gold-bearing gravela 

 underlying Tertiarj^ lava. The finding 

 of a human akull embedded in such de- 

 posits was for a time believed to indict tp 



ney, then State geologist, accepted the 

 skull as a bit of genuine scientific evi- 

 dence, it is generally believed by stu- 

 dents of the antiquity of man that the 



Calav 



auriier 



grav 



