A popular guide to minerals : with chapters on the Bement Collection of minerals in the American Museum of Natural History, and the development of mineralogy . tig. 303 Fig. 304 GUIDE TO COLLECTIONS 113. Fig. 316 Fig-314 PLATE 14 114 A POPULAR GUIDE TO MINERALS the sandstone or, according to Irving and Chamberlain, haveformed sheets between successive beds of these coarse, sandy an(^pebbly conglomerates. From this latter view we derive the impression of a period ofvolcanic activity, succeeded by a period of rest during which theconglomerates and sandstones were deposited, which again was fol-l
A popular guide to minerals : with chapters on the Bement Collection of minerals in the American Museum of Natural History, and the development of mineralogy . tig. 303 Fig. 304 GUIDE TO COLLECTIONS 113. Fig. 316 Fig-314 PLATE 14 114 A POPULAR GUIDE TO MINERALS the sandstone or, according to Irving and Chamberlain, haveformed sheets between successive beds of these coarse, sandy an(^pebbly conglomerates. From this latter view we derive the impression of a period ofvolcanic activity, succeeded by a period of rest during which theconglomerates and sandstones were deposited, which again was fol-lowed by renewed ejections of doleritic or igneous matter in theirturn to be sealed in by later shore or shoal water beds of sand-stone. At the contact between these contrasted beds and developedthrough them the copper is found in strings, sheets, crystals andmasses. The theory which most adequately accounts for this re-markable development is, comprehensively stated, this: the slowlyrising columns of igneous rock have brought with them fromdeeply seated areas or entrapped in their flow through the earthscrust, a great volume of copper salts; these in a heated state havemet surface waters carrying
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmineral, bookyear1912
