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Ammonites appear basalt basin beds bones Boulder-clay boulders Brachiopoda calices Carboniferous Chalk character clay cliffs Coal Coal-measures coast corallites crater Cretaceous crust denudation deposits depth described Devonian district drift Eich elevation elytron Eocene eruption existence faults fauna feet flint formation fossils fragments genus Geol Geological Magazine Geological Survey geologists glacial glaciers granite gravel Greensand ground 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 seam seen septa shale shells side Silurian species specimens stones strata striae surface teeth Tertiary theory thickness thin Triassic Upper valley valve volcanic whilst
Seite 294 - Globigerince of the chalk differed from those of the existing species. But if this be true, there is no escaping the conclusion that the chalk itself is the dried mud of an ancient deep sea. In working over the soundings collected by Captain Dayman, I was surprised to find that many of what I have called the
Seite 141 - 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 eft'ect in producing the apparent dip of overlying beds.
Seite 415 - 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 424 - Arran, <fec. lu conclusion he draws attention to the many variations in composition and texture in the same rock-mass, and accounts for them thus : — If the lava were simply in a viscid state, with the ingredients imperfectly mixed, portions of it must, on consolidation, contain them in various proportions, just as is known to be the case in imperfectly fused slags. He maintains that there is an absolute identity of composition, structure, and mode of occurrence in these eruptive rocks of very...
Seite 140 - 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 380 - Derby, were covered with thick ice, which in most parts reached down to the sea, and that extensive snow-beds prevailed over the rest of England. In the summer months the melting of these would give rise to streams of muddy water, and produce the superficial deposits of Brick-earth, Warp, and Loess ; whilst, when the currents were stronger, perhaps from the thaw being unusually rapid, deposits of gravel would be formed. This second ice-sheet would gradually become less and break up into valley-glaciers,...
Seite 187 - Secretaries: David Forbes, Esq., FRS ; Rev. T. Wiltshire, MA Foreign Secretary : Warington W. Smyth, Esq., MA, FRS Treasurer : J. Gwyn Jeffreys, Esq., FRS Council : The Duke of Argyll, KT, DCL, FRS ; H. Bauerman, Esq. ; Prof. G. Busk, FRS ; JF Campbell, Esq. - Frederic Drew, Esq. ; Sir P.
Seite 424 - 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 415 - 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 570 - ... were once probably trachytes, these old Cumbrian rocks might perhaps be called Felsidolerites, answering in position to the modern Trachy-dolerites. A detailed examination of Cumbrian ash-rocks had convinced the author that in many cases most intense metamorphism had taken place, that the finer ashy material had been partially melted down, and a kind of streaky flow caused around the larger fragments.