Transactions . Bection across Wlieal Alfred, Gwinear,-Cornwall. Rich ore occurs in thedike only. (From De la Beche.) Vein Split in Traversing JointedElvanDike. (De la Beche,Geol. .06s., p. 779.) planation that the physical texture and chemical compositionof the country-rock affect the deposition of ore, and declaresthat it was undoubtedly the carbonaceous matter of the rockat Rico which acted as a precipitant. This example differs,therefore, from that of Pontgibaud, where feldspar has beenreplaced by silver-bearing galena. V ihart, Montana.—At this locality the veins show a remark-able variati
Transactions . Bection across Wlieal Alfred, Gwinear,-Cornwall. Rich ore occurs in thedike only. (From De la Beche.) Vein Split in Traversing JointedElvanDike. (De la Beche,Geol. .06s., p. 779.) planation that the physical texture and chemical compositionof the country-rock affect the deposition of ore, and declaresthat it was undoubtedly the carbonaceous matter of the rockat Rico which acted as a precipitant. This example differs,therefore, from that of Pontgibaud, where feldspar has beenreplaced by silver-bearing galena. V ihart, Montana.—At this locality the veins show a remark-able variation in richness, corresponding to differences in thewall-rock. Mr. Robert H. Raymond, the former manager ofthe Diamond R. properties, found that the veins were barrenin the dark-colored gneisses, and held ore-bodies in the pink orwhite feldspathic gneiss. My own observations enabled me toconfirm this in a general way, and also showed that in amphib-olite the vein was barren as well as narrow, and that no work-
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
