The deposits of the useful minerals & rocks; their origin, form, and content . d which in part were filled with gold ore. Theformation of the gold lodes in the Sierra Nevada may therefore to acertain extent be regarded as the last phase of the Mesozoic crustalrevolution in that region. Since that time these momitains have beendry land. In the latter portion of the Neogene or latest Tertiaryperiod, volcanic eruption and plication began anew, rhyolite and andesitebeing extruded to form those gigantic lava masses which give to the SierraNevada their present configuration. Since according to Lindg
The deposits of the useful minerals & rocks; their origin, form, and content . d which in part were filled with gold ore. Theformation of the gold lodes in the Sierra Nevada may therefore to acertain extent be regarded as the last phase of the Mesozoic crustalrevolution in that region. Since that time these momitains have beendry land. In the latter portion of the Neogene or latest Tertiaryperiod, volcanic eruption and plication began anew, rhyolite and andesitebeing extruded to form those gigantic lava masses which give to the SierraNevada their present configuration. Since according to Lindgren the gold lodes are of Cretaceous or inpart of pre-Cretaceous age, the relation they maintain to the older north-north-west mountain folds is striking. These lodes form many systems,and often appear on the surface in long lines of quartz outcrops. Previous to the exhaustive investigation of Lindgren in 1895, thenumerous works upon Californian lodes and mining districts had not ledto any general conclusions, as the individual authors had only investigated 606 ORE-DEPOSITS.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
