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Ammonites appear basalt basin beds bones Boulder-clay boulders Brachiopoda calices Carboniferous Chalk character clay cliffs Coal Coal-measures coast containing coral corallites crater Cretaceous crust denudation deposits depth described Devonian district drift Eich elevation elytron Eocene eruption existence fauna feet flint formation fossils fragments genus Geol Geological Magazine Geological Survey geologists glacial glaciers granite gravel Greensand Guppy heat hills Hybodus inches Ireland Keuper Kimmeridge Clay land lava Lias Limestone lower M'Coy Mallet margin marls mass miles mineral Miocene mountain nearly Neocomian observed occur Oolite origin Palaeozoic Pand paper period Permian plates Pliocene porphyry portion present probably Prof quarry referred remarked ridges rocks sand Sandstone Scrope seam seen septa shale shells side Silurian species specimens stones strata surface teeth Tertiary theory thickness thin Triassic Upper valley valve volcanic whilst
Seite 143 - Geological Survey of England. The author referred to many instances in which beds have unequal development, being much thicker in some places than in others ; and the main object of his paper was to show that such thickening and thinning of beds has an important effect in producing the apparent dip of overlying beds.
Seite 417 - There is, then, no alternative but to accept the result, that a Tertiary flora was contemporaneous with a Cretaceous fauna, establishing an uninterrupted succession of life across what is generally regarded as one of the greatest breaks in geologic time.3 As bearing on the subject of the Lignitic formation considered as Eocene, Prof.
Seite 142 - Rhine flowed in a minor valley through the upland country formed of Devonian rocks which now constitute the Taunus, the Hundsruck, and the highland lying towards Bonn ; and by the ordinary erosive action of the great river the gorge was gradually formed and deepened to its present level, in proportion as the gorge deepened, the marly flat Miocene strata of the area between Mainz and Basel were also in great part worn away, leaving the existing plain, which presents a deceptive appearance of having...
Seite 431 - ... result of the melting of a vast thickness of land-ice, charged throughout -with stones and boulders of nearly every kind of rock occurring •within the area in which the body of the ice originated. 19. "Geological Observations made on a Visit to the Chaderkul, Thian Shan range.
Seite 350 - The greater elevation of the land is simply assumed as an hypothesis to account for the cold.* The facts of geology, however, are fast establishing the opposite conclusion, viz., that when the country was covered with ice, the land stood in relation to the sea at a lower level than at present, and that the continental periods or times when the land stood in relation to the sea at a higher level than now were the warm inter-glacial periods, when the country was free of snow and ice, and a mild and...
Seite 426 - Cyrena fluminalis occurs in them. The author regards them as deposits from a great expanse of fresh water kept back by a barrier of polar ice descending far towards the south. In its greatest extension this ice-barrier would produce the crushing of the bed-rock ; and as it retreated, the water coming down from the higher ground in the south would cover a continually increasing surface. 4. " On the Microscopic Structure and Composition of British Carboniferous Dolerites.
Seite 382 - ... warp, and loess ; whilst when the currents were stronger, perhaps from the thaw being unusually rapid, deposits of gravel would be formed. This second icesheet would gradually become less and break up into valleyglaciers, which in their retreat would leave kaims and eskers at low levels, and moraines in the mountain-glens. During this time no new great submergence of the country took place ; and the last great modifications of the surface were sub-aerial, and not submarine, the work having been...
Seite 417 - I regard the evidence derived from the mollusks in the lower beds and the vertebrates in the higher as equally conclusive that the beds are of Cretaceous age. There is, then, no alternative but to accept the results that a Tertiary flora was contemporaneous with a Cretaceous fauna...
Seite 314 - In the regions where most of these icebergs were met with, the mean density of the sea is about 1'0256. The density of ice is -92. The density of icebergs to that of the sea is therefore as 1 to 1*115 ; consequently, every foot of ice above water indicates 8'7 feet below water. It therefore follows that those icebergs 400 feet high had 3,480 feet under water— 3,880 feet would consequently be the total thickness of the ice. The icebergs which were 500 feet high would be 4,850 feet thick, those 600...
Seite 308 - A slope of one degree continued for 1,400 miles will give twenty-four miles as the thickness of the ice at the pole. But suppose the slope of the upper surface of the cap to be only one-half this amount, viz., a half degree, — and we have no evidence that a slope so small would be sufficient to discharge the ice, — still we have twelve miles as the thickness of the cap at the pole. To those who have not been accustomed to reflect on the physical conditions of the problem, this estimate may doubtless...