210 



GUIDEBOOK OF THE WESTERN UNITED STATES. 



far away to the soutlieast. 



mming c€ 

 ttlements 



Hoi 



side of a wooded ridge and suddenly, at the south end of the ridge, 



irn. Until this year (1915) the 



tpe Hor 

 summit 



Tk of American . 

 in Plate XLIX 



A. Now the old Ime ^^ around Cape 

 Horn^' has been abandoned, and railroad traffic goes thi^ough double 

 tunnels built to eliminate what had seemed hkc a danirerous curve 

 around the point. Turning back along the other side of the spur, 

 the raiboad crosses a deep ravine up which runs the narrow-gage 



from Colfax to Grass Vallev and 



This ravine, 



Jurassic age (M 



le North Fork of American River, is cut m slate of 

 iriposa slate). This formation and some of the 

 altered slaty or schistose volcanic rocks associated with it (amphibo- 

 lite schist, greenstone, etc.) contam some of the principal gold- 



bearing quartz 

 known as the \ 



veins of California 



ding the series of veins 



^ The Mother Lode, so called because 



miners ima; 



sort of ancestral relation to smaller lodes, 



mi 



Fork of American Elver southward for 

 fully 120 miles, past the towns of Placer- 

 ville, Amador, Sutter Creek, Jackson, San 

 Andreas, Angels, Jamestown, Jackson- 

 ville, Coulterville, and Mariposa. It is 

 not, as the name implies, a single great 

 vein, but a remarkable linear system of 

 closely parallel and overlapping veins, 

 some of which are many miles in length. 

 The lode has the same general trend as 

 the belta of slaty or schistose rock that are 

 characteristic of the western mid-Sierra 

 elope and follows in the main a very per- 

 sistent belt of Marinosa slfitp j^lthmio-r, 4f 



ing free gold, auriferous pjTite, and other 

 minerals that are less constantly or less 

 abundantly present. They were de- 

 posited in early Cretaceous time by hot 

 waters probably given off, in part at least, 

 by deep-ljT^ng, slowly cooUng masses of 

 granite (ffranodiorite'). 



mines 



Bunker 



Phonouth 



nfi 



In 



places the ilother Lode veins are in al- 

 tered schistose igneous rocks (amphibo- 

 Kte schist or greenstone schist), in slaty 

 rocks of the Calaveras formation, or even 

 in serpentine. 



The slaty rocks of the Mother Lode re- 



gion generally dip eO"* to 





E., and 



eins 



'lined than the rocks 



The veins consist chiefly of quartz carry 



Lmcoln, Wildman-Mahoney, Eureka, 

 Amador, Central Eiu-eka, South Eureka, 

 Oneida, Kennedy, Argonaut, Zeila, Gwin, 

 Gold Cliff, Lightner, Utica, Melones, 

 Rawhide, Dutch, App, Eagle-Shawmut, 

 and Princeton. Not all of these are now 

 active. The deepest mine and one of the 

 most productive is the Kennedy, which 

 has a vertical shaft 4,000 feet deep. 



The ore of the ilother Lode is treated 

 in stamp mills, and the gold is recovered 

 partly by amalgamation and partly by 

 concentration and cyanidation of the 

 pjTite and other 8uli>hides present. The 

 gold quartz mines of California produce 

 annually gold valued at from $10,000,000 



000 



The 



1 



comes irom the mines along 

 Lode. 



