Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/365

 1869.] WALLBEIDGE CANADA WEST. 269 College, Toronto, are of value, as showing the average quality of the ores found in this locality : — No. 1. From Madoc. dwts. grs. Gold = 3 12 per ton. Silver = 7 14 ?j No. 2. Ditto. Gold = 7 20 Silver =18 7 No. 3. Ditto. Gold = 5 21 Silvers 14 9 No. 4. Ditto. Gold =19 12 Silver = 3 4 No. 5. From Madoc. oz. dwts. grs. Gold =1 17 2 per ton Silver =0 4 14 „ No. 6. Ditto. Gold =1 11 17 „ Silver = 6 12 „ No. 7. Ditto. Gold =1 1 9 „ Silver =0 3 8 .. No. 8. From Marmora. Gold =1 19 5 „ Silver =0 5 5 „ lY. On the Occukeence op Iron-ores. It has long been known that extensive deposits of valuable iron- ores occur in the Laurentian rocks of the North Riding of Hast- ings. These ores rarely, if ever, occur in true veins, but are usually found in bedded masses, more or less distinctly interstratified with the adjacent rocks, and in many cases appearing at the junction of the gneiss with crystalline limestone. The ore-deposits traverse the townships of Madoc, Marmora, and Belmont in a general east and west direction, thus following to some extent the common trend of the strata. The iron is found sometimes in the form of magnetic ore, and sometimes in that of hsematite. As many of these beds of magnetic iron-ore have been ably de- scribed in the Heports of the Geological Survey of Canada, it is needless to give any detailed notice of them in the present paper. Such is the famous " big ore bed" of Crow Lake, situated on the eighth lot of the first concession of Belmont. This is the ore which was formerly smelted at the Marmora Iron Works. Above the surface of the ground, the bed exhibits a width of about 500 feet ; but recent excavations at the base show that it attains a stiU greater development below. The " Seymour ore bed," on the eleventh lot of the fifth range of Madoc, has also been described. This was at one time worked to a limited extent to supply the Seymour furnace at Madoc. As magnetic iron-ore is very widely distributed through the county, it would be tedious to note its many places of occurrence ; but I may perhaps call attention to a new locahty in Madoc, on the nineteenth lot of the first concession, which yields a fine magnetic ore [of which samples were exhibited]. A large deposit of mag- netic iron-ore, also hitherto undescribed, is found on lot nine of the sixth range of Madoc. Before dismissing the subject of magnetic iron-ores, it may be mentioned that the deposits of this mineral attain so extensive a development as to form, in many cases, remarkable physical features of the country. Indeed the supply of ore which might be obtained by working these deposits would be practically inexhaustible. Smelted with wood- charcoal, or with peat, which must necessarily V 2