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Show SOME ORE DEPOSITS YOUNG Newly Formed Veins Have Produced Such Famous Mining Camps ai Goldfleld and Tonopah. Ore deposits ranging in age from ti.e time when the most complei liv;;.; thing on the earth was a crablike ores ture down to the time when mamms! were highly developed have been four In this country. Among the your:;'" deposits is a group known to gists as the late tertiay veins. These veins are widely distribute; and are of particular interest not or. ? : because they have given rise to famoi: j mining camps such as Tonopah, GoiJ- j field and Comstock, but because, owir.: to their comparative youth, the surface on which they crop out is not greati? below that whoch existed at the tic of their origin. Thus by consider: the surface conditions and by laboratory labora-tory experiments the phenomena the? present can be interpreted more accurately accu-rately than those of older deposit which are at greater depths and are more deeply cut by erosion. Many of the late tertiary veins in this country, all inclosed in lava rocfo or closely associated with them, a found In Nevada. |