. Bulletin of the Geological Society of America. Geology; Geology -- United States. 162 PROCEEDINGS OF COLUMBUS MEETING. ically. In Mr. Dale's report to Professor Raphael Pumpelly, United States geolo- gist, dated March, 1890, he described the locality in the following words: â¢â¢East of Great Barrington, at the Searles-Hopkins quarry, a rather coarse-grained muscovite biotite gneiss is in contact with a micaceous pyritiferous dolomite. An analysis of the dolomite is given by Mr. A. A. Julien in his paper on the geoiogy of Great Barrington (Trans-artions of tin .V u York Academy of Science, vo
. Bulletin of the Geological Society of America. Geology; Geology -- United States. 162 PROCEEDINGS OF COLUMBUS MEETING. ically. In Mr. Dale's report to Professor Raphael Pumpelly, United States geolo- gist, dated March, 1890, he described the locality in the following words: â¢â¢East of Great Barrington, at the Searles-Hopkins quarry, a rather coarse-grained muscovite biotite gneiss is in contact with a micaceous pyritiferous dolomite. An analysis of the dolomite is given by Mr. A. A. Julien in his paper on the geoiogy of Great Barrington (Trans-artions of tin .V u York Academy of Science, vol. v, 1887, page :;7). The plicated stratification planes of the gneiss dip at th'- contact r;n0-4(i0 west, and westerly dips occur also along the steep part of tin.' base Of mount Keith, both north and south of the quarry, hot the gneiss on the hill due south of the reservoir has a stratification dip only a tew degrees east or west of 90°. The cleavage-foliation dip at the quarry is. however. 60° east. The relations of tie' stratification-foliation to the cleavage-foliation are shown in the accompanying sketch, made from a specimen. The general relations of stratification and cleavage in the schists of Berkshire county were set forth in my report on the areal and structural geology of mount ; U SuRvKY SHEFntlt* â¢S-hEET. ClTea t square Fool. "Plicated Quart* veins and cleavage FoliaCton uxnUiscavite-BiotiXc- 6nfciv5 near Hof>Kiu% QuanTY, )n 1na>-cK imp ' B3te Figure 'â '>.âCleavagt ami Bi'lnimj near Great Barrington (after Dale). The Hopkins-Searles quarry lies very near the line separating the portions of territory allotted to Mr. Dale and myself fur study. Ignorant of the fact that he had examined the locality, I visited it in July, 1890, and arrived at the same con- clusions concerning the general structural relations that he had reached in the previous season. Figure 4 shows the probable relations at the
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