Julys, 1884] 



NA TURE 



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the North- West Territories, and from the reports and maps of 

 the scientific men who had accompanied the various Arctic 

 expeditions by sea and land. Specimens and interesting notes 

 on the geology of Great Slave Lake had been received from 

 Capt. H. P. Dawson, R.A., who had spent last year there in 

 charge of the Canadian Station of the Circumpolar Commission. 

 The distribution of the various formations from the oldest to the 

 newest was illustrated by a large geologically-coloured map of 

 the whole Dominion. Referring first to the Laurentian system, 

 Prof. Bell showed that it forms the surface-rock over an 

 enormous area of circular form on the main continent, and that 

 the central part is occupied by the waters of Hudson's Bay, 

 which are surrounded by a border of Palseozoic rocks. If we 

 included the Laurentian rocks of Greenland and the Atlantic 

 coast from Newfoundland to Georgia, it would be observed that 

 their general outline corresponds with that of the continent, 

 which has been built up around this ancient nucleus. The 

 Huronian strata, which constitute the principal metalliferous 

 series in Canada, were closely associated with the Laurentian, 

 and appeared to be always conformable with them. The largest 

 and best-known areas were between Lake Huron and James's 

 Bay, but Dr. Bell had found four belts of them on the east coast 

 of Hudson's Bay, and others had been recognised in the primitive 

 region to the west of it. Indeed wherever the older crys- 

 talline rocks had been explored in Canada, belts having 

 the character of the Huronian series had been met with. 

 Limestones, slates, and quartzites, interstratified with amygda 

 loids, basalts, &c, corresponding with the Nipigon formation of 

 Lakes Superior and Nipigon were largely developed on the 

 Eastmain coast and adjacent islands of Hudson's Bay, and appa- 

 rently also on the Coppermine River and to the westward of it. 

 But a set of hard red siliceous conglomerates and sandstones 

 were seen to come between the Huronian and the Nipigon series 

 at Richmond Gulf on the Eastmain coast, which appeared t<> be 

 unconformable to both. Mr. Cochrane and Dr. Bell had found 

 similar rocks on Athabasca Lake, Capt. Dawson, R. A., on 

 (heat Slave Lake, and Sir John Richardson to the north-east of 

 Great Bear Lake. The conglomerates, slates, and gray argil- 

 laceous quartzites of Churchill and the white fine-grained 

 quartzite of Marble Island were probably of this horizon. 

 Silurian rocks were well known to be widely spread on some of 

 the largest of the Arctic islands, and along the most northern 

 channels of the Polar Sea. They formed an irregular and inter- 

 rupted border on the western side of Hudson's and James's Bays. 

 A large basin of Devonian strata, containing gypsum and clay- 

 ironstone, extended southward from James's Bay. West of the 

 great Laurentian area, Devonian rocks could be traced here and 

 there all the way from Minnesota to the mouth of the Mackenzie 

 River. They were not, however, so widely distributed as had 

 been supposed by the older travellers, who had passed rapidly 

 through the country in the early part of the century, when the 

 whole subject of American geology was in its infancy. The so- 

 called bituminous shale of Sir John Richardson and others, so 

 prevalent along the Athabasca and Mackenzie Rivers, was found 

 by Prof. Bell to consist of soft Cretaceous strata, saturated and 

 blackened by the petroleum rising out of the underlying Devonian 

 rocks, which here, as in Ontario, Ohio, and Pennsylvania, are 

 rich in this substance. The principal features and the geogra- 

 phical distribution of the Carboniferous, Liassic, Cretaceous, and 

 Tertiary rocks of the northern regions were next described. 

 Among other points of interest in reference to the post-Tertiary 

 period, Dr. Bell mentioned that the remains of both the mastodon 

 and mammoth had been found on Hudson's Bay, and that there 

 were reports of the occurrence of elephants' tusks on an island in 

 its northern part. Isolated discoveries of elephantine remains 

 had been made in the North- West Territories and several on the 

 Rat River, a tributary of the Youkon, near the borders of Alaska. 

 In referring to the economic minerals, Prof. Bell said that even 

 the coarser ones, such as granite, limestone, cement-stone, slate, 

 flagstones, gypsum, clays, marls, ochres, sand for glass-making, 

 moulding, &c, would yet have their value in different parts of 

 the great region under consideration. Soapstone, mica, plum- 

 bago, asbestos, chromic iron, phosphate of lime, salt, pyrites, 

 &c, had been noted in different localities. Among ornamental 

 stones known to occur, might be mentioned the rare and beauti- 

 ful mineral lazulite discovered by Dr. Bell at Churchill, also 

 malachite, jade, agate, cornelian, chrysoprase, &c. Lignites 

 of various qualities, some being very good, were found in many 

 places throughout the great tract occupied by the Cretaceous and 

 Tertiary rocks of the Athabasca-Mackenzie Valley and on the 



coasts and islands of tire Arctic Sea ; also in Tertiary strata at 

 Cumberland Bay and in Greenland, on the opposite side of 

 Davis' Strait. The lignites found by Dr. Bell on the Albany 

 and Moore Rivers were of post-Tertiary age. Anthracite of fine 

 quality had been found on Long Island in Hudson's Bay. True 

 bituminous coal had been reported to occur on Banks' Lam', 

 Melville, and Bathurst Islands. Petroleum, which proceeded 

 from Devonian strata as elsewhere in North America, was very 

 abundant along the Athabasca and Mackenzie Rivers, and vast 

 quantities of asphalt resulting from the drying up of the exuding 

 petroleum were found on the Athabasca, around Great Slave 

 Lake, and at various places in the interior. In reference to the 

 metals, the ores of iron were abundant. Inexhaustible quan- 

 tities of rich manganiferous carbonate of iron existed on the 

 islands of the Manitounik chain. It lay in beds upon the sur- 

 face over hundreds of square miles, and was broken up by the 

 frost into pieces of convenient sizes for shipping. Valuable de- 

 posits of magnetic iron had been found on Athabasca and Knee 

 Lakes, and a great bed of pure clay-ironstone on the Mattogomi 

 River. Capt. Dawson had found a vein of specular iron on 

 Great Slave Lake. Copper ore had been met with on Hudson's- 

 Bay and near Lake Mistassini, and large quantities of the 

 native metal were known to occur on the Coppermine River. A 

 band of limestone, running from Little Whale River to Rich- 

 mond Gulf, was rich in galena. Zinc, molybdenum, and man- 

 ganese had been found on Hudson's Bay, and antimony in the 

 north. Both gold and silver had been detected in veins on the 

 Eastmain coast, and alluvial gold had been washed out of the 

 gravel and sand of the streams among the mountains in the tract 

 to the west of the lower part of the Mackenzie River, which 

 Dr. Bell thought might yet become the great gold and silver 

 region of the north, corresponding with Colorado and Nevada 

 to the south. The fine gold-dust found in the drift in one section 

 of the North Saskatchewan may have been derived, during the 

 Glacial period, from the upper valleys of the Liard, on one of which 

 the famous Cassiar gold district is situated ; although Dr. Bell 

 had some years ago originated the theory that this gold might have 

 come from Huronian rocks in the district to the north-eastward 

 of Edmonton. — "Note sur certains depots auriferes de la 

 Beauce," by the Rev. Prof. Laflamme, D.D. — " Decouverte 

 de l'emeraude au Saguenay," by the same. — Description 

 of a supposed new Ammonite from the Upper Cretaceous- 

 rocks of Fort St. John on the Peace River, by Prof. J. F. 

 Whiteaves, F.G. S., &c. ; On a new Decapod Crustacean from 

 the Pierre Shales of Highwood River, N.W.T., by the same. 

 The Ammonite referred to in the first of these communications 

 appears to be a previously undescribed species of Prionocyc.'us, 

 closely allied to the type of that genus, the Ammonites woolgari 

 of Sowerby, but with much more closely coiled volutions. It 

 occurs in flattened nodules, in shales which are believed to be 

 the equivalents of the Fort Benton group of the Upper Missouri 

 section. The Decapod Crustacean from Highwood River, a 

 tributary of the Bow, is doubtfully referred to the genus Hoplo- 

 pur.a of McCoy. — Notes on the manganese ores of Nova Scotia, 

 by E. Gilpin, M.A., F.G.S. — A revision of the geology of A nti- 

 gonish County, Nova Scotia, by the Rev. D. Honeyman, D.C.L. 

 — "Notes stir la constitution geologique de l'Apatite Cana- 

 dienne," by S. Obalski. 



THE FAINS AND THE RECENT VOLCANIC 

 ERUPTIONS 1 



'I HE rains this year have been more persistent than usual. At 

 Perpignan they have been extraordinary. Is it necessary 

 to see any relation between this circumstance and the recent vol- 

 canic eruptions ? The beautiful crepuscular colorations of the 

 past autumn and winter have been attributed to these eruptions ; 

 ought we also to attribute to them the extraordinary spring 

 rains ? I should be inclined to believe it. It is acknowledged 

 that the presence in the atmosphere of solid particles facilitates 

 the condensation of vapour. This would be in conformity 

 with the position maintained by Mr. Aitken in his paper 

 on Dust, Fog, and Clouds (volume for 1SS0-81, Trans. R.S.E.). 

 He concludes thus : — " In an atmosphere saturated with vapour, 

 but free from dust, there is formed neither cloud nor fog ; when- 

 ever the vapour of water is condensed in the atmosphere, it is 

 owing to the presence of those solid particles, each of which 

 becomes, so to speak, a centre of condensation, or the nucleus 

 of a small crystal of ice." 



1 Paper read at the Paris Academy of Sciences by M. Gay, June 23. 



