Observations on Metalliferous Deposits, and on Subterranean Temperature ...W. Cornish, 1871 |
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4me Série adjoining afforded Annales des Mines Asiatic Researches Asiatic Society auriferous beds Brazil Brazilian Mining Association calcareous CAPTAIN HERBERT Chañarcillo chlorite clay-slate Colorada lode columns Commissioner Batten Copiapò copper Cornwall Geol cross-veins d'el Rey Company depth district earthy brown iron-ore east Eschwege Extracts fathom level fathoms feet felspar formation Geological Transactions gneiss gold Gongo Gongo Soco gossan Government Calcutta granite Henwood hornblendic Huel Ibid Imperial Brazilian Mining inches ingredients iron Jacotinga John d'el Rey joints Journal laminæ limestone lode manganese Martius masses metal micaceous Minas Geraes miners mixed Morro Morro Velho native silver Official Reports oxydulated Pluto Pluto Brasiliensis portions Proportion of Silver pyrites quantities quartz quartzose Records of Government Reise in Brasilien Reports on Kumaon rich rock Saint John d'el schist schistose shaft siliceous silver-ore slate sometimes Spix strata surface talc talcose thick Trans Troy veins weight whilst wrought yielded
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Seite 397 - ... condition of the whole, as to render their positive or proximate equivalence highly probable, if not almost certain; and the conclusive evidence given of the age of the Huron, would thus appear to settle that of the Lake Superior rocks, in the position given to them by Dr. Houghton, the late State Geologist of Michigan, as beneath the lowest known fossiliferous deposits...
Seite 488 - ... of its geographical geology, and that in fact he had made these references, only to render more intelligible what he wished to say upon the subject of the metalliferous veins of the district. It is a fact well known, that south from the district referred to, transported masses of native copper are occasionally met with, in the diluvial deposits which are so abundantly spread over the country; and these loose masses are distributed over an area of many thousand miles, including southern Michigan,...
Seite 141 - Cornwall Geol. Trans., vp 411. • " The metalliferous mountain of Marmato in the province of Popayan in " New Granada, is situate in the midst of immense forests. The stream by " which the stampers are worked is formed by the union of many small brooks.
Seite 481 - The temperature of the water of Lake Superior during the summer, a fathom or two below the surface, is but a few degrees above the freezing point. In the western portion, the water is much colder than in the eastern — the surface flow becoming warmer as it advances toward th outlet.
Seite 602 - Cock, their hardihood tempted them to follow the ore upwards even to the sea ; but the openings made were very small, and the rock being extremely hard, a covering of wood and cement in the two former, and a small plug in the latter mine sufficed to exclude the water, and protected the workmen from the consequences of their rashness. In all these, and in Wheal Edward and Levant, I have heard the dashing of the billows and the grating of the shingle overhead even in calm weather.
Seite 427 - The vein is remarkably regular in its course, which is about north 27° west, and its underlay is about 10° to the east. In the lower levels its dip is more varying. Some parts of it expand to three or four feet in width, other portions are pinched up to a few inches, but its average width is probably from 15 to 18 inches.
Seite 490 - On the side of a rivulet, ten leagues to the south of Lake Superior in North America, there is a single lump of native copper, about four tons weight, free from any mixture but a few small black Stones of an Iron nature, and some very fine grains of Crystal. * * * No vein of copper was discovered on the south side of the Lake, near this lump ; but some few very small ones on the north side, not worth the pursuit. This I had from two credible Miners of...
Seite 369 - Government, then assayed, marked according to their value, and delivered to the owners, with a certificate to render them current. For the greater convenience of trade, gold-dust was likewise permitted to circulate for small payments. Notwithstanding these strict regulations, a considerable quantity of the precious metal in its original state found its way to Rio de Janeiro, Bahia, and other ports, clandestinely, without paying the royal fifth...
Seite 396 - ... differs, in a very marked degree, from the prevailing character of this rock, as developed in New York and Canada, where it is usually, though not always, compact. It is not, however, unlike the sandstone of the Pictured Rocks, and is less friable than that of the Mississippi and St. Croix region. The almost uninterrupted continuity with which this rock can be traced, even from its eastern extension through Canada and along the northern shore of Lake Huron to the St. Mary's river, and thence...
Seite 151 - To prevent their shoulders from being hurt, (for the miners are generally naked to the middle) they place a woollen covering (frisada) under this bag. We meet in the mines with files of fifty or sixty of these porters, among whom there are men above sixty, and boys of ten or twelve years of age.