Show SOME ORE D DEPOSITS POSITS YOUNG Newly Formed Veins Have Produced Such Famous Mining Camps as Goldfield and Tonopah Ore deposits ranging in ago age from the time when the most complex living thing on the earth was a crablIke creatura creature creature crea crea- ture tura down to the time when mammals were highly developed have been found In this country Among the younger deposits is a group known to geologists as the late tertia tertiary y veins These veins are widely distributed and are of particular interest not only because they have given rise to famous mining camps such as Tonopah Goldfield Gold- Gold Goldfield field and Comstock but because owing to their comparative youth the surface on which they crop out is not greatly below that existed at the time of t t origin Thus by considering the surface conditions and by laboratory laboratory labora labora- tory Story experiments the phenomena they 1 present resent can be interpreted more accurately accurately accurately than those of older deposits which are at greater depths and are anore wore deeply cut by erosion Many of the late tertiary veins Inthis Inthis in inthis this country all in lava rocks or closely associated with them are found In Nevada |