378 V. DOLMAGE.

of a very coarsely. crystalline specularite and, besides occurring in the ore veins, is plentifully distributed through the country rocks for a considerable distance from the veins. Samples of it collected by Robertson? assayed: copper, 6.7 per cent.; silver, 26.8 0z.; gold, 0.83.0z.; and copper, 6.6 per cent. ; silver, 58 0z.; gold, 1.68 oz. per ton. A number of specimens of this specu- larite were examined under the microscope, both the metal- lographic and the petrographic. The thin flakes which cleave off easily, when mounted in sealing wax and cleaned with a chamois, make excellent preparations for the reflecting microscope. All of these that were studied were found to be perfectly homogeneous under the oil-immersion lens. Polished sections were also ex- amined and in a few, chalcopyrite was found interlaminated with the leaves of hematite, but only in minute quantities. The prep- arations studied under the petrographic microscope transmitted a brownish-red ray, showed no pleochroism, and a very weak double refraction. They also appeared perfectly homogeneous. In view of these facts it is very difficult to explain the presence of so much silver and gold, unless the samples taken by Mr. Robertson contained also a considerable amount of magnetite. Magnetite is almost as plentiful as hematite, and is associated with numerous specks of copper sulphides and silver minerals. The zinc blende is also a peculiar type, and occurs in flat lenses in the quartz associated with chalcopyrite. It is quite transparent when poilshed, but when taken from the vein is coated over with a thin black film, which, with its well-developed cleavage, gives it the appearance of hematite. The zinc blende is highly impreg- nated with chalcopyrite and the white mineral already referred to. The chalcopyrite is fresh and homogeneous and replaces the hematite and zinc blende. Bornite was seen in only one specimen and there in very small amounts.

Oxidation has produced a considerable amount of limonite and a little covellite. |

These metallic minerals were associated with quartz and large quantities of epidote. The quartz has preceded hematite which

2 Robertson, W. Fleet, Annual Report of the Minister of Mines, British Columbia, 1905, p. J—120.