Transactions of the Geological Society of Glasgow, Volume 4The Society, 1874 - Geology |
Other editions - View all
Common terms and phrases
appear Beith bores boulder clay Campsie Carboniferous cent character Clyde coal colour Craig cutting D'Orb deposits depth district dolerites drift ice east erratics evidence exhibited feet Foraminifera formation fossils fragments Gala Group Geikie Geological Society Geological Survey geologists glacial glacier Glasgow Glen hills Hope Street Hosie limestone inches ironstone JAMES THOMSON JOHN YOUNG Kilmalcolm laminated clay land ice Linn locality Loch Lomond lower bed M'Coy main limestone marine miles mineral Moderately common Moderately rare neighbourhood north-east north-west observed occur Old Red Sandstone overlying Paisley period Phil pitchstone porphyrite portion present Professor quarry referred remarks river Robertson rocks Sand and gravel schist Scouler sedimentary Seedhills seen shale Shale over Hosie Shale under main shells shore side Silurian species specimens spines stones strata striæ striated striations surface thickness trap upper bed valley Vice-President West of Scotland William WÜNSCH
Popular passages
Page 307 - ... part of the change produced in the former. We know too little of the changes in the interior of the earth accompanying such changes on its surface to be able to state results with certainty. But he estimated that an elevation, for example, of 600 feet on a tract of the earth's surface 1000 miles square and 10 miles in thickness, would only alter the position of the principal axis by one-third of a second, or 34 feet. He called attention to the effect of tidal friction and subterranean viscosity...
Page 305 - ... above and below mean level*. He noticed, in passing, the application of these dynamical principles to the attraction which the sun and moon exercise on the protuberant parts of the earth, tending to bring the plane of the earth's equator into coincidence with the ecliptic. This causes an incessant change, to a certain limited extent, in the position of the axis of rotation, thereby occasioning what is known as the "precession of the equinoxes.
Page 59 - ... the ice must have attained. He then proceeded to consider the formation of the boulder clay, holding that the lower Till or clay was the product of this great sheet of...
Page 193 - Mr. Douglas here refers to Dr. Scouler'a having carried away from the Columbia River, the preserved skulls of two Chenooks, on account of the singular mode in which, by compressing the frontal bone in infancy, the heads of these people are made to assume a conical, almost sugar-loaf appearance. The indignation of the natives was much roused on this occasion, and Dr. Scouler would probably have met with very rough treatment, if he had not deferred this robbery for the sake of science to the very night...
Page 306 - ... while it has been inhabited by plants and animals, it has been practically rigid. Changes of climate, then, have not been produced by changes of the axis of the earth. The learned professor then inquired what influences great subsidences or great elevations in different parts of the earth might have on the axis of rotation. No doubt the removal of a large quantity of solid matter from one part of the globe to another would sensibly alter the principal axis, as well as the axis of rotation, which...
Page 307 - ... thickness, would only alter the position of the principal axis by one-third of a second, or 34 feet. He called attention to the effect of tidal friction and subterranean viscosity in reducing any such deviation, and pointed out that it must be exceedingly slow ; using for evidence the observationally proved slowness of the diminution of the earth's rotational velocity, and of the inclination of its equator to the ecliptic. It therefore seemed probable that geological changes had not produced...
Page 308 - ... sufficiently moist to prevent its cracking. 3. The metamorphic rocks in' the west of the island, of Laurentian age. Their dip, and strike, and mineral character differ so widely from the other sedimentary rocks of the island as to furnish sufficient warrant for placing them in that position. He was not prepared to speak with any degree of certainty regarding the source of the materials constituting the basic conglomerate mass. These differ so widely from the granites found in situ in other parts...
Page 85 - Gilmorehill quarry, about nine inches in thickness, showing in that space thirty-two well-defined alternate white and dark-brown stripes, which gave the specimen a beautifully stratified appearance. Mr. Young stated that the brown stripes were due to the particles of sand having become mixed with bituminous matter previous to their deposition. It was perhaps not easy to explain the alternation, so oft repeated, of these white and coloured bands, but he thought the stripes could not have been so clear...
Page 86 - Oldhamia from Bray Head, near Dublin. He described minutely the position of the beds in which these fossils are found, and complained that geological references are frequently so vague as to be of little real service to one going over the ground for himself. Two species of this fossil had been discovered (0.