Ground water in the Norwalk, Suffield, and Glastonbury areas, Connecticut . t, staurolite, and in places magnetite,graphite, pyroxene, and chlorite. Originally this formation was aseries of clays, silts, and sands that were consolidated into shalesand sandstones, v^^hich in tiy:n have been subjected to great pressureand heating and have been metamorphosed. In places in Glastonburythe rock is very dark gray, as it contains a good deal of graphite de-rived from organic materials in the original sediments. The Boltonschist underlies a northward-striking belt a quarter of a mile widethat runs thro
Ground water in the Norwalk, Suffield, and Glastonbury areas, Connecticut . t, staurolite, and in places magnetite,graphite, pyroxene, and chlorite. Originally this formation was aseries of clays, silts, and sands that were consolidated into shalesand sandstones, v^^hich in tiy:n have been subjected to great pressureand heating and have been metamorphosed. In places in Glastonburythe rock is very dark gray, as it contains a good deal of graphite de-rived from organic materials in the original sediments. The Boltonschist underlies a northward-striking belt a quarter of a mile widethat runs through the eastern part of the village of South Glaston-bury, and a belt half a mile wide nekr the east boundary, includingBirch Mountain, from which it extends south-southwest. This for-mation is very resistant and everywhere makes ridges that stand upabove the neighboring formations. ^ Gregorj, H. E., and Robinson, H. H., Preliminary geolo^cal map of Connecticut:Connecticut Geol. and Nat. Hist. Survey Bull. 7, 1907. IS. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 470 PLATE XH. MASSlVl!: GRANITE GNEISS, EAST GLASTONBURY, CONN. GLASTONBUllY. 155 The Glastonbury granite gneiss underlies an area of about 26square miles, including Minnecbaug Mountain, Kongskut Mountain,Eightmile Hill, and Meshomasic Mountain. It is quarried forbuilding stone at a number of places. According to Gregory,^ itmay be cUvirted into two parts—;i bvoud western portion, decidedly gnelssoid audusually dark colored, with a large quantity of biotite and hornblende; anarrower eastern portion, more granitic, and in places reaching the raassive-ness of a true granite. * * ^^^ As seen in the abundant expovsures west ofthe Portland Reservoir, it is a dark, well-foliated, almost schistose gneiss offine grain, which on the cleavage surface shows alternating patches of blackbiotite and white feldspar. * * * The presence of biotite aud hornblende,arranged in parallelism with aggregates of feldspar, gives a distinct foliati
Size: 1199px × 2084px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, bookpubl, booksubjectwatersupply
