Annual report . Geology of Southeastern Ontario 25 schist is about two hundred feet wide, measured across the schistosity, while in Roddybay, near the mouth of the North river, the schist is very much thinner. There appearsto be a gradual transition, in ascending order, between the greenstone schist, quartz-mica schist and limestone. (3) Iron formation (banded chert or granular quartz).—The iron formation has beenso-called on account of its resemblance to certain cherty rocks of the iron ranges in theVermilion district of the Lake Superior region and elsewhere. In the Belmont lakearea three be
Annual report . Geology of Southeastern Ontario 25 schist is about two hundred feet wide, measured across the schistosity, while in Roddybay, near the mouth of the North river, the schist is very much thinner. There appearsto be a gradual transition, in ascending order, between the greenstone schist, quartz-mica schist and limestone. (3) Iron formation (banded chert or granular quartz).—The iron formation has beenso-called on account of its resemblance to certain cherty rocks of the iron ranges in theVermilion district of the Lake Superior region and elsewhere. In the Belmont lakearea three belts have been found, viz.: (a) One hundred feet east of the bridge overDeer river at the north end of Belmont lake, a belt about twenty feet wide and twohundred feet long is exposed. It is made up of dark red, coarse chert, or granular quartz,interbanded with calcite. The cherty bands are from an inch to two feet thick, eachband sometimes showing alternate lines of darker and lighter chert. Thin sections show. Fijr. 7.—Iron formation (jaspilyte), Grenville scries. About one-half mile west ofDeer bav, Belmont lake. the material to be made up of interlocking grains of quartz which form the base. Mag-netite and hematite grains occur disseminated among the quartz grains, without showingany tendency to surround individual grains. The octahedra of magnetite can occasion-ally be detected with the naked eye, but they are for the most part in minute hematite can be recognized with high powers of the microscope in blood-red grains,but it occurs also in thin layers which lie roughly parallel to the strike and dip of therocks in general in this area. It is the hematite in dust-like condition that gives thechert its reddish, jasper-like color, while hematite and magnetite together produce adark purple effect. Two analyses for metallic iron gave and 15 per cent, respectively,the former probably being nearer an average, (b) About half a mile southwest of theoutcrop describ
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectminesandmineralresou
