Annual report . rocks,there occur bodies of magnetite, such as those at the Blairton mine on the shore of Crowlake, to the east of the borders of the map of the Belmont lake area, and at the Belmontiron mine, immediately south of Cordova. The finer-grained variety of the rock makesgood road material. PALEOZOIC SYSTEM The Paleozoic system is represented by horizontal beds of Ordovician, Black River,limestone, with usually, at tfie base, calcareous- sandstone often of a red color due to thepresence of iron oxides. At other times the pure limestone rests directly on the pre-Cambrian rocks and hol
Annual report . rocks,there occur bodies of magnetite, such as those at the Blairton mine on the shore of Crowlake, to the east of the borders of the map of the Belmont lake area, and at the Belmontiron mine, immediately south of Cordova. The finer-grained variety of the rock makesgood road material. PALEOZOIC SYSTEM The Paleozoic system is represented by horizontal beds of Ordovician, Black River,limestone, with usually, at tfie base, calcareous- sandstone often of a red color due to thepresence of iron oxides. At other times the pure limestone rests directly on the pre-Cambrian rocks and holds a few angular fragments of them. 34 Bureau of Mines No. 4 Analysis of Paleozoic Limesti ne A sample of limestone from a small quarry just east of Havelock was found to have the following chemical composition, showing it to be, like most Black River limestones,low in magnesia:* Lime Magnesia Alumina Ferric oxide Sulphur trioxide Carbon dioxide Loss Silica Total I itf. 15.—Qreenstone Of Keewatin scries in which the amygdules are still 25, concession 6. Helmont township. Relationships * /,. lation of On m HU s< ri< 8 to tin /<? • watin.—The Keewatin green schists, originallyessentially volcanic rocks, are considered to form the basement. On the ropy, tufaceousand uneven surface of the Keewatin were deposited sediments now represented by cal-careous quartz-mica schist, iron formation, dolomitic linn stone, and finally by pure lime-stone. No erosion unconformity prt ceding that immediately below the Hastings serieshas been observed. The deposition of the older sediments, including the iron formationand dolomitic limestone, probably closely Followed the submarine lava flows of theKeewatin. The purer or non-dolomitic limestone is the youngest of the pre-Hastings * Ont. Bur. Mines, Vol. XIII. Part 2, p. 98. 1913 The Pre=Cambrian Geology of Southeastern Ontario 35 sediments, and was deposited towards the c
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectminesandmineralresou
