The Orange County copper district in east-central Vermont includes an ar«a about 20 mile* long and 5 miles wide, elongate north-south* It contains thre* important «ine», the Elizabeth, Ely, and Eureka** Union* The district yielded important amounts of copper befor« 1882, mostly from the Ely mine, but has since been only a small and intermittent producero Total production is estimated to be between 50 and 60 million pounds of copper* folds in their vicinity. It it suggested that th* Eureka-Ohion de~ posits nay be connected to a similar shoot at moderate depth, and thia possibility could readily be tested by drilling* Geologic factors that should be considered in connection with geophysical prospecting are discussed, and a number of favorable areas for geophysical prospecting are described.Detailed descriptions of individual mines «rd prospects, ex*» eluding the Elisabeth nine, uhlch has been described in an earlier report, follow the general discussion*
Of the four late Pleistocene and early post-Pleistocene lithic complexes defined by Edward P. Lanning, only one, the Las Vegas complex, is supported by existing evidence from the Santa Elena Peninsula of southwest Ecuador. The Achallan culture, previously defined by Stothert and assigned to the post-Las Vegas period, is now unsupported by satisfactory evidence.
The Perm mine deposits in Calaveras County, Calif., are in slightly metamorphosed Jurassic volcanic rocks and intrusive quartz porphyry, Bedding, schistosity, and cleavage strike northwest and dip steeply northeastward. Two main types of faults are present: high-angle schistosity faults, and younger low-angle reverse faults. There are six main alteration zones, in which rocks have been sericitized, silicified, and pyritized. The ore bodies are sulphide replacement deposits either at contacts of.alteration zones, or along.faults within these zones. The ore bodies are steeply pitch-'"' ing lenses. Their pitch length ranges from 150 to 1,000 feet; breadth, from 100 to AGO feet; width,; from ^4 to^30 feet. The ore is a mixture of pyrite, sphalerite, chalcopyrite,-and a little bornite and tetrahedrite, Gangue minerals are barite, calcite, and quartz. t; Reserves.are estimated to be 245>100 tons of minings-gradevore^ and from 913>000 to £73,000 tons of low-grade ore. Two: types of areas favorable for exploration are listed: (1) extensions of kncwrLjore bodies, and (2) locations considered geologicalZy>ffayorable for the existencejof ore boidiesi? ^twarranted by the demand ifor copper and zinc, exploration of-these areas vis recommended.
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