File:Transactions (1871) (14753870116).jpg

Identifier: transactionsmining27amer (find matches)
Title: Transactions
Year: 1871 (1870s)
Authors: American Institute of Mining, Metallurgical, and Petroleum Engineers
Subjects: Mineral industries
Publisher: New York (etc.)
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: University of Toronto

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ered as follows: a, Coarse, pebbly conglomerate, with beds of sandstone ; 6, Laminated sand-stone; c, Shales (fossiliferous); d, Coarse, pebbly conglomerate; e, Shales andthin-bedded sandstone (fossiliferous) ; /, Shales (fossiliferous and hard gray sand-stone) ; g, Coarse, pebbly conglomerate ; h, Phoenix or Upper shales, comprisingc, d, e,f, and cj; i, Shales ; j, Angular grit (probably volcanic ash) ; k, Greenish,highly fossiliferous sandstone; I, Conglomerate ; in, Green crystalline rocks;n, Shaes (First bed of slate ) ; o, Fine grained, hard gray sandstone ; p, Al-tered coarse, pebbly conglomerate; q, Altered graywacke (semi crystalline) ;r, Shales ( Second bed of slates ) ; s, Coarse, pebbly conglomerate ; t, Porphyry(probably diabase-porphyry); «,, Hard, cryslalline greenstone ; v, Green and purplechloritic rock, in parts amygdaloidal ; cavities filled with carbonate of lime (vol-canic, probably an amygdaloidal diabase). The questions suggested by the foregoing conditions are:
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580 THE GENESIS OF CERTAIN AURIFEROUS LODES. 1. The shales being evidently the favorable country-rock, wasthe gold leached out from them, carried into the lode-fissuresand there precipitated? In this connection, it will be interest-ing to note whether the pyrite in the shales carries gold bothnear and away from the lode, and whether the non-pyritousshales are gold-bearing. Moreover, in view of the favorableinfluence of the greenstone, is the source of the gold to befound in the silicates, pyrite or other minerals of the green-stone ? 2. If the country-rock is found to be auriferous, is the goldin it, or in the pyrite or other mineral which it contains, de-rived from the lode, which has in turn received it from a sourcedeeper than any of the rocks exposed ? Samples collected from the North Phoenix mine, by Mr.Alfred Lord, of Gympie, were analyzed with the results shownin Table X. and Diagram 5. While this number was not asgreat as I could have wished, the samples taken were fairlytypic

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