All the geological information concerning the western coast of Hudson bay to the northward of Wager inlet is contained in the narratives of the voyages of Parry and Dr. Rae. The explorations of Rae ended at Repulse bay. He reported only Laurentian rocks along the coast, with granite-gneisses predominating, these being accompanied by considerable areas of greenstones, showing the rocks in the northern part to be very like those along the southern shores of Roes Welcome.
Parry explored the west side of Fox channel from Frozen strait to Fury and Hecla strait. The result of his observations has been summarized by Dr. Dawson as follows:
‘The geological specimens brought back were examined by Prof. Jameson, and the detailed maps of the expedition include indications of the character of the rock at so many places, as to afford the means of tracing the geological outlines with very considerable accuracy. Granitic and gneissic rocks occupy the whole of the southern part of the east shore of Melville peninsula, and are continued northward behind a low track of limestone country, forming a range of mountains in the centre of the peninsula to Hecla and Fury strait. They also form the south shore of this strait, and most of the islands in it, and apparently the whole eastern shore of the adjacent south part of Cockburn “island.”
‘The rocks referred above, in a general way, to the Archæan, 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 association with these the following minerals occur: “Zircon and beryl, also precious garnet, actinolite, tremolite, diallage, coccolite, 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 Archæan, and in addition 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 summary 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 consisted 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 consisted 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.’
‘The Marble island quartzites are composed of hard white quartzite, consisting of more or less rounded grains of quartz, of moderately regular size, cemented together by interstitial silica. They are very distinctly bedded in thick and thin beds, and the surfaces of the beds are often covered with beautiful ripple-markings. The heavier beds also often show distinct false bedding. They are usually in a more or less inclined attitude, but they were nowhere seen to be very much crumpled or squeezed into minute folds. Their total thickness was not determined.’
‘These quartzites were first noted by Dr. Bell from Marble island, and although this island was not examined by the writer, rocks of undoubtedly similar character to those described by Dr. Bell, were seen in many places along the shore, and consequently the name is here retained.’