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The bent and metamorphosed condition of the calcite shows the shearing and crushing which the rock has undergone. 11 Phyllite same location as No. 9. A dark red, finely laminated rock consisting chiefly of decomposed biotite and feldspar, occasional quartz grains and sericite and much iron oxide.
The lowest bed of a calcarous sericitic schist is four feet thick and underlies a bed of schistose lime stone six feet in thickness, which is in turn covered by a finely laminated phyllite, ten feet thick. The whole is capped by thirty feet of quartzite, which forms the top of a long ridge.
Early stages of metamorphism are seen in SLATE. Pressure has hardened the marine muds, the arkose, or the volcanic ash from which slates are derived, and has caused them to cleave by the rearrangement of their particles. Under somewhat greater pressure, slate becomes PHYLLITE, a clay slate whose cleavage surfaces are lustrous with flat-lying mica flakes.
The one exception is on Caribou Ridge, which is capped by a much altered gabbro. The first noticeable change in the character of the country rock is a Washkagama Lake, where a fine grained epidotic schist was observed, having a dip 82 degrees W. and a strike S. 78 degrees E. At Otter Lake a much foliated and weathered phyllite was found. Strike N. 73 degrees E. and a dip of 16 degrees.
Owing to the strong weathering action this thickness of quartzite is doubtless much less than it was originally. Forty-six miles above Seal Lake an exposure of phyllite was seen, the same in every respect as the one east of Seal Lake, just mentioned. The general direction of foliation is S. 70 degrees E. and the dip 70 degrees.
MICA SCHIST, the most common of schists, and in fact of all metamorphic rocks, is composed of mica and quartz in alternating wavy folia. All gradations between it and phyllite may be traced, and in many cases we may prove it due to the metamorphism of slates and shales. It is widespread in New England and along the eastern side of the Appalachians.
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