MINEEALS OF HUDSON BAY AND NOETIIKRN CANADA. 243 



part of Great Bear Lake and Coronation Gulf, which appears to correspond with the hard 

 red conglomerates and sandstones just described. 



The Nipigon formation is largely developed along the East-main coast of Hudson Bay, 

 between Cape Jones and Cape Dufferin, and consists of compact non-fossiliferous bluish- 

 grey limestone, coarse cherty limestone -breccia, quartzites, shales, diarites, amygdaloids 

 and manganiferous clay-ironstones. The limestones of Lake Mistassini, in the interior of 

 the Labrador peninsula, bear a strong resemblance to those of the East-main coast, and are 

 probably of the same age. Similar limestones, associated with trap, are described by 

 Richardson as occurring on the shores of the Arctic Sea, between the Mackenzie and the 

 Coppermine Rivers. The native cox^per of the former stream is associated with rocks, 

 which, from Richardson's description, appear to be similar to those of the Nipigon series. 

 Non-fossiliferous limestones, like those of this formation, form the greater part of the spurs 

 of the Rocky Mountains, which run north-eastward across the lower • part of the Mac- 

 kenzie River, and we may have here a great development of the Nipigon formation. 



A border of Silurian rocks (principally limestones) extends along a considerable por- 

 tion of the western shore of Hudson Bay, and stretches inland one hundred miles on the 

 Nelson River. To the west and south-west of James Bay, Silurian limestones and marls 

 form a wide belt between the great Devonian basin of that region and the Laurentian 

 rocks of the interior, their base, or western limit, on the main Albany River, being 200 

 miles, in a straight line, from the sea, and 230 miles on the Kenogami or principal south- 

 ■western branch of the same stream. On the western side of the Laurentian nucleus, 

 Silurian limestones run north-westward through Manitoba and may be traced as far as 

 Isle à la Crosse Lake. But these strata are most widely spread in the north over the great 

 islands beyond the Arctic Circle, between Baffin Bay and the open ocean to the west, and 

 the polar sea to the north. 



Devonian rocks, consisting of limestones, shales and marls, with gypsum and clay- 

 ironstone, form a large basin to the south-west of the head of James Bay. Strata of this 

 age are found here and there, following a north-westerly course, all the way from the 

 southern part of Manitoba to the mouth of the Mackenzie River. They do not, however, 

 appear to occupy so extensive an area as had been supposed by the earlier explorers. 

 What they had described as " bituminous shales," belonging to this system, were found by 

 Dr. Bell to be really soft, fine-grained. Cretaceous sandstone, saturated and blackened by 

 petroleum, and which, after exposure to the weather, scaled off in flaggy pieces, which, 

 at a short distance, resemble coarse shale. In this region the Devonian rocks, rich in fossils, 

 lie in immediate and almost conformable contact with these blackened strata, so that 

 this error was easily made. The same conditions may extend northward, from the mouth 

 of the Mackenzie to Banks Land, and the Melville archipelago and the supposed Carbon- 

 iferous rocks of these regions may consist of lignite-bearing Cretaceous sandstones,, asso- 

 ciated with Devonian strata, in which some of the fossil forms resemble others in the Car- 

 boniferous. 



Fossils, supposed to be of Liassic age, have been found at Capes York, Horsburgh and 

 Warrender, in bright red sandstones, which form conspicuous features in the landscapes 

 at these points ; and, again, on Exmouth, Bathurst and Prince Patrick Islands ; and 

 Richardson states that Liassic strata occupy a basin along the ÏTth parallel of latitude, all 

 the way from the 95th to the 120th meridian. 



