MINING. 291 



principal mining towns are Downieville, Monte Cristo, Pine 

 Grove, St. Louis, La Porte, Poker Flat, Eureka City, Forest 

 City, Alleghany Town, and Cox's Bar. One of the most re- 

 markable features of the placers of the state is the blue lead, 

 which was first discovered in Sierra county, and has been more 

 thoroughly examined there than elsewhere. The "blue lead" 

 is a stratum of blue clay very rich in gold. It is found deep 

 under other strata. The general opinion is, that the blue lead 

 occupies the bed of a large antediluvian river, which ran parallel 

 with the Sacramento and about sixty miles eastward of it. It 

 has been traced twenty miles or more, passing near Monte 

 Cristo, Alleghany Town, Forest City, Chip's Flat, and Zion Hill. 

 Mr. C. S. Capp wrote thus to the San Francisco Bulletin : 



" This is not one of the many petty leads, an inch or two in 

 breadth and thickness, which, after being traced a few hundred 

 feet, end as suddenly and mysteriously as they commence ; but 

 it is, evidently, the bed of some ancient river. It is often hun- 

 dreds of feet in width, and extends for miles and miles, a thou- 

 sand feet below the summits of high mountains, and entirely 

 through them. Now it crops out where the deep channels of 

 some of the rivers and ravines of the present day have cut it 

 asunder ; and then, hidden beneath the rocks and strata above 

 it, it only emerges again miles and miles away. Wherever its 

 continuity has been destroyed, the river or gulch waiich has 

 washed a portion of it away, was found to be immensely rich 

 for some distance below, and the materials of which the lead is 

 composed are found with the gold in the bed of the stream. 

 It is evidently the bed of some ancient stream, because it is 

 Walled in by steep banks of hard bed-rock, precisely like the 

 banks of rivers and ravines in which water now runs, and be- 

 cause it is composed of clay which is evidently a sedimentary 

 deposit, and of pebbles of black and white quartz, which 

 could only be rounded and polished as they are by the long- 

 continued action of swiftly running water. The bed-rock in 

 the bottom of this lead is worn into long smooth channels, and 

 also has its rouo-hnesses and crevices like other river-beds. 



