The deposits of the useful minerals & rocks; their origin, form, and content . separate districts anda general review hadnot fallen to the lotof any single author-ity. The dependenceof the lodes upon thebelt of metamorphicslates was already re-cognized by in the graniteareas of southernCalifornia but fewlodes occur—andthese only close tothe slate boundary—in the slate region ofmiddle and northernCalifornia many arefound, all the differ-ent rocks within themetamorphic beltparticipating fairlyequally, ore-depositsbeing found in gran-ite, diorite, gabbro,serpentine, quartz-porphyrit
The deposits of the useful minerals & rocks; their origin, form, and content . separate districts anda general review hadnot fallen to the lotof any single author-ity. The dependenceof the lodes upon thebelt of metamorphicslates was already re-cognized by in the graniteareas of southernCalifornia but fewlodes occur—andthese only close tothe slate boundary—in the slate region ofmiddle and northernCalifornia many arefound, all the differ-ent rocks within themetamorphic beltparticipating fairlyequally, ore-depositsbeing found in gran-ite, diorite, gabbro,serpentine, quartz-porphyrite, augite-porphyrite, horn-blende-porphyrite,diabase, amphibolite,as well as in more orless altered clay-slate,sandstone, and lime-stone. Since gold - quartzconglomerates arefomid in the foot-wallof the metamorphicseries, some of thelodes most certainlywere of very greatage ; as pointed out Fig. 313.—The Californiau gold belt. THE OLD GOLD LODES 607 by Whitney, and von Richthofen however, the majority and the richestare late Jurassic or early Cretaceous, and to be reg
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
