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Epidote likewise occurs in the gneiss in thin layers, parallel to the foliation of the mass. One large vein of a coarse granitic character was remarkable from in one part quite changing its character, and insensibly passing into a blackish porphyry, including acicular crystals of glassy feldspar and of hornblende: I have never seen any other such case.
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.
The uppermost beds of the porphyritic conglomerate, on which the gypseous strata conformably rest, are variously coloured, with one very singular and beautiful stratum composed of purple pebbles of various kinds of porphyry, embedded in white calcareous spar, including cavities lined with bright-green crystallised epidote.
The porphyritic lavas are highly amygdaloidal, both on their upper and lower surfaces; they consist chiefly of claystone porphyry, but with one common variety, like some of the streams at the Puente del Inca, having a grey mottled basis, abounding with crystals of red hydrous oxide of iron, green ones apparently of epidote, and a few glassy ones of feldspar.
5-Mica Granite Gneiss Country Rock near Caribou Ridge. In the hand specimen the rock has the same appearance as No. 4, if anything, it is somewhat more compact. The principal minerals are, plagioclase, biotite and microcline, with smaller quantities of quartz, iron oxide, pyroxene and garnet. The feldspar is decomposed with the resulting formation of epidote, which is quite prominent.
A very heavy, compact, greenish-black stone, with a fine-grained obviously crystalline basis, containing a few specks of white calcareous spar, many specks of the crystallised hydrous red oxide of iron, and some specks of a green mineral; there are veins and nests filled with epidote: certainly a submarine lava. 20th. Many thin strata of compact, fine-grained, pale purple sandstone. 21st.
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