Report on the Geology and Topography of a Portion of the Lake Superior Land District in the State of Michigan: Copper landsHouse of Reps, 1850 |
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Página 20
... trappean hills , which in their widest expansion do not exceed twelve miles , or attain an elevation greater than 900 feet above the lake . The southern coast is less rock - bound and irregular than the northern . The principal ...
... trappean hills , which in their widest expansion do not exceed twelve miles , or attain an elevation greater than 900 feet above the lake . The southern coast is less rock - bound and irregular than the northern . The principal ...
Página 59
... rocks , or those which were supposed originally to have been deposited by water and subsequently modified by heat ... trappean rocks , being a complex and difficult subject , will be separately described in the chemical part of the ...
... rocks , or those which were supposed originally to have been deposited by water and subsequently modified by heat ... trappean rocks , being a complex and difficult subject , will be separately described in the chemical part of the ...
Página 61
... trap- pean range , narrow belts of trap have been observed in two places ... rocks , and undoubtedly results from chemical affinity , by which the par ... rocks , in their westerly prolongation , preserve a remark- able parallelism . This ...
... trap- pean range , narrow belts of trap have been observed in two places ... rocks , and undoubtedly results from chemical affinity , by which the par ... rocks , in their westerly prolongation , preserve a remark- able parallelism . This ...
Página 62
... rock , corresponding in position to this band . The trappean rocks above and below this belt exhibit great differences in lithological character - the upper being highly crystalline , while the lower are amygdaloidal . This belt , lying ...
... rock , corresponding in position to this band . The trappean rocks above and below this belt exhibit great differences in lithological character - the upper being highly crystalline , while the lower are amygdaloidal . This belt , lying ...
Página 65
... rock forming one of the jutting points of the bay ; but here it assumes a different character , as though it had been ... trappean and detrital rocks , is a belt of chlorite in foliated masses which expands to about 150 feet in thickness ...
... rock forming one of the jutting points of the bay ; but here it assumes a different character , as though it had been ... trappean and detrital rocks , is a belt of chlorite in foliated masses which expands to about 150 feet in thickness ...
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Términos y frases comunes
adit afford amygdaloid appearance bands bearing north bedded trap belt bluffs boulders calc-spar Carp river chlorite clay cliffs coast compact trap Company composed conglomerate consists containing Copper Harbor crystalline depth distance drift deposites east elevation epidote excavated explorations extended fissures gangue geological granite greenstone Harbor height hills hornblende hundred feet igneous rocks inches intersect iron island Isle Royale Keweenaw Point lake shore Lake Superior limestone lode mass metal Michigan miles mineral mines Montreal river mountains native copper nearly northern northwest numerous observed occur Ontonagon river pebbles places Porcupine mountains porphyry Portage lake portion prehnite quarter of section quartz range 34 region ridge rises sand sandstone Saut seam seen shaft silver slope southeast southern southwest spar strata stratification stream striæ summit surface thickness tons township 58 traced trap range trappean rocks traversed vein veinstone vicinity width
Pasajes populares
Página 9 - The groves were God's first temples. Ere man learned To hew the shaft, and lay the architrave, And spread the roof above them — ere he framed The lofty vault, to gather and roll back The sound of anthems ; in the darkling wood, Amid the cool and silence, he knelt down, And offered to the Mightiest solemn thanks And supplication.
Página 149 - The rubbish taken from the mine is piled up in mounds, which can readily be distinguished from the former contour of the ground.
Página 209 - Fault, in the language of miners, is the sudden interruption of the continuity of strata in the same plane, accompanied by a crack or fissure varying in width from a mere line to several feet, which is generally filled with broken stone, clay, &c.
Página 7 - I have seen several such pieces in the hands of savages; and since they are very superstitious, they esteem them as divinities, or as presents given to them to promote their happiness by the gods who dwell beneath the water. For this reason they preserve these pieces of copper wrapped with their most precious articles.
Página 54 - 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 the outlet.
Página 149 - He saw numerous evidences to convince him that this was an artificial excavation, and at a subsequent day, with the assistance of two or three men, proceeded to explore it. In clearing out the rubbish they found numerous stone hammers, showing plainly that they were the mining implements of a rude race. At the bottom of the excavation they found a vein with ragged projections of copper, which the ancient miners had not detached.
Página 119 - It is on the rivers, and the boatman may repose on his oars ; it is in highways, and begins to exert itself along the courses of land conveyance ; it is at the bottom of mines, -a thousand feet below the earth's surface ; it is in the mill, and in the workshops of the trades. It rows, it pumps, it excavates, it carries, it draws, it lifts, it hammers, it spins, it weaves, it prints.
Página 149 - The earth was so packed around the copper as to give it a firm support. The ancient miners had evidently raised it about five feet and then abandoned the work as too laborous. They had taken off every projecting point which was accessible, so that the exposed surface was smooth.
Página 120 - ... fortunate circumstance, not only to the company, but to the whole mining interest on Lake Superior. It gave encouragement to those engaged in these pursuits, and induced them to persevere. It also demonstrated the true source from which the loose masses occasionally found on the lake shore had been derived. It demolished the fanciful theory advanced by at least one geologist as to the transport of the...
Página 149 - When he had penetrated to the depth of eighteen feet, he came to a mass of native copper ten feet long, three feet wide, and nearly two feet thick, and weighing over six tons. On digging around it the mass was found to rest on billets of oak, supported by sleepers of the same material. This wood...