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probably include areas of Huronian. Jameson mentions as 

 among the prominent varieties of rocks derived from this 

 region, " Granite, gneiss, mica-slate, clay-slate, chlorite-slate, 

 primitive-trap, serpentine, limestone and porphyry." In asso- 

 ciation with these the following minerals occur : " Zircon and 

 beryl, also precious garnet, actinolite, tremolite, diallage, cocco- 

 lite, rock crystal, calc-spar, rhomb-spar, asbestos, graphite or 

 black lead, specular iron ore, magnetic iron ore, chromic ore or 

 chromate of iron, titanic iron, common and magnetic iron 

 pyrites." Some of the " transition rocks " noticed by Jameson 

 should probably also be classed with the Archaean, and in addi- 

 tion to several of the minerals above mentioned, in these were 

 found tourmaline (schorl) and molybdenite.' 



The coast between the mouth of Chesterfield inlet and 

 Churchill, was examined by Tyrrell, and the following sum- 

 mary of the geology is taken from his report : 



' On the low flat shores of Hudson bay between Seal river and 

 Cape Esquimaux few rock exposures occur, but those seen con- 

 sisted of granites and gneisses of typical Laurentian aspect. 

 For forty miles north of Cape Esquimaux no rock in place was 

 seen, and thence northward to Baird bay some of the points con- 

 sisted of granite and gneiss, though the shore generally consisted 

 of Huronian rocks.' 



' The largest area of Huronian rocks found in this district 

 extends more or less continuously for 120 miles along the west 

 coast of Hudson bay, from near Baker's foreland to a point 45 

 miles north of Cape Esquimaux.' 



' The rocks constituting this system may be divided into three 

 more or less distinct groups, viz. : The Marble island quartzites, 

 the greenish quartzites and graywackes, and the more or less 

 highly altered, and often schistose diabases and gabbros.' 



1 The Marble island quartzites are composed of hard white 

 quartzite, consisting of more or less rounded grains of quartz, 



