Show SILVER PEAK quadrangle QUA bRANGLE ore deposits of the silver peak quadrangle nevada is the title of a professional paper no 55 recently published by the united states geological survey which will be welcome as a valuable addition to the library of the mining geologist and the professor of geology it is a notable contribution to the literature on the theory of ore deposits a subject to which the author mr josiah edward spurr has already devoted 0 considerable attention in his previous writings after describing the general geology of the silver peak quadrangle mr spurr takes alkes up the deposits of this area in detail describing their genetic relations developing ve loping finally from these observations the theory of veins of quartz briefly stated the authors conclusion is that some auriferous quartz bodies may be of origin and may indeed be regarded as a phase of magmas hagmas this conclusion supports the theory which he proposed in 1898 to explain the auriferous quartz veins of the yukon districts in alaska the whole theory including the transition of quartz veins to peg marites and these to rocks was at that time original with him but by continued study he finds that more and more of it had been anticipated until practically the only portion left which he can consider as original is the conclusion that quartz veins which are really the ultra siliceous form of the magma may contain metals especially gold in sufficient quantity to constitute ores and the corollary later announced noun ced that gold quartz veins are especially connected with intrusive bodies of rocks minerals also occur in the silver peak quadrangle and deposits of these are described by mr about ten miles north of silver peak there is a deposit of alum and sulfur in rhyolite the several playas within the quadrangle contain incrustations of common salt and borates of lime and solda the borax industry is dormant at present but has been of considerable sid erable importance boron is one of the rarer elements and occurs principally in deposits from dry lakes or in deposits from volcanic fuma roles coal occurs in the tertiary sediments at the north end of the silver peak range the chief seams are four in number the coal is of rather poor quality containing a good deal of ash however it might possibly be used as a gas coal |