Transactions . eon the maps, Plates X. and XL, and on the two sections AAand BB, Figs. 7 and 8. A A is of especial interest, because itis based on both surface observations at a place of good out-crops, and on two drill-holes, Xos. 162 and 163, which lie onits line. Samples from 163 have been microscopically deter-mined, and have furnished one of the most important checkson the stratigraphy. The sections exposed by the two holes are important, becausethey show that the contrasted sheets of gneiss are quite regularand persistent for considerable distances. In depth, moreover,in No. 163, at 75 f
Transactions . eon the maps, Plates X. and XL, and on the two sections AAand BB, Figs. 7 and 8. A A is of especial interest, because itis based on both surface observations at a place of good out-crops, and on two drill-holes, Xos. 162 and 163, which lie onits line. Samples from 163 have been microscopically deter-mined, and have furnished one of the most important checkson the stratigraphy. The sections exposed by the two holes are important, becausethey show that the contrasted sheets of gneiss are quite regularand persistent for considerable distances. In depth, moreover,in No. 163, at 75 feet below the ore the gabbro-gneiss gaveplace to a narrow sheet of the Barton gneiss, 25 feet thick,which was followed by the gabbro-gneiss for 62 feet, and thenafter penetrating the Barton gneiss for 5 feet the hole the surface,as the small outliers show, the Barton gneissextends both northeast and southwest. The same is true of the gabbro-gneiss. GEOLOGY OF THE MAGNETITES NEAR PORT HENRY, N. Y. 185. VOL. XXVII.—13 186 GEOLOGY OF THE MAGNETITES NEAR PORT HENRY, N. T. In sections CC and BDD, Figs. 9 and 10, the relations areagain shown stratigraphically, the determinations in hole No. Fig. 9.
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
