A hard compact rock of dark green color, having a mottled appearance, due to the presence of a white mineral.
Pyroxene, quartz and augite form the groundmass, as seen in section. There are a few small grains of magnetite.
The severe crushing to which the rock has been subjected has resulted in the conversion of the plagioclase into scapolite and also in the formation of zoisite by the characteristic alteration of the lime bearing silicate of the feldspar in conjunction with other constituents of the rock.
The light mineral is finely granulated and the whole is marked by uneven extinction.
The rock has probably been derived by dynamic metamorphism, from a coarse igneous rock like a gabbro.
7—Epidotic Sericitic Schist. Washkagama Lake.
A fine grained compact gray rock, of aggregate structure, consisting chiefly of quartz, plagioclase and biotite, and the alteration products epidote and sericite.
Under the microscope it is a confused mass of finely granulated minerals, with numerous included crystals.
The rock has undergone complete metamorphism and its origin is unknown.
8—Phyllite-Near Otter Lake.