The Physical Geology & Geography of IrelandE. Stanford, 1878 - 291 páginas |
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amongst Antrim basalt blocks Boulder Clay Carboniferous beds Carboniferous Limestone Carlingford Central Plain centre channel Clew Bay Close coal-field coast Coloured conglomerates Cork denudation deposited direction district Donegal Dublin dykes east elevation England epoch evidence feet flanks formation Galway Bay Geol geological map Geological Survey glacial glacier granite gravel grits Harbour Hardman Highlands hills ice-movement ice-sheet inches Island Journ Jukes Kerry Killary Harbour Kinahan lakes land Lough Allen Lough Mask Lough Neagh Lower Boulder Clay Lower Silurian marine masses Mayo metamorphic miles Miocene moraine mountains northern numerous observed Old Red Sandstone origin period Permian Pliocene probably Professor Ramsay quartzite represented ridge rise river schists Scotland shales Shannon sheets shores Silurian Silurian beds Silurian rocks slates slopes southern southwards strata stream striæ surface terraces tion tracts Upper Boulder Clay Upper Silurian valley volcanic Wales waters Wicklow Wicklow Mountains
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Página 233 - The crystal will not form to suit the cavity, the cavity must be made to contain the crystal. And what holds true of one molecule, holds true of every molecule which melts and resolidifies. This process is therefore going on incessantly in every part of the glacier, and in proportion to the amount of heat which the glacier is receiving. This internal molecular pressure, resulting from the solidifying of the fluid molecules in the interstices of the ice, acts on the mass of the ice as an expansive...
Página 146 - ... of trap which radiate from, or traverse, the whole district, all point to this region as having been the seat of great volcanic activity. Nor ought we to omit reference to the remarkable mass of agglomerate made up (as on the southern flanks of Slieve Gullion) of bombs of granite which have been torn up from the granitic bases of the hill below, and blown through the throat of an old crater, as conclusive evidence that these rocks in some ices were erupted at the surface of the land of the period.
Página 232 - ... too narrow to contain it. The result will be that the fluid molecule in passing into the crystalline form will press the two adjoining molecules aside in order to make sufficient room for itself between them, and this it will do, no matter what amount of space it may possess in all other directions. The crystal will not form to suit the cavity, the cavity must be made to contain the crystal.
Página 166 - British area. At this time Ireland contributed to the future mineral wealth of England ; she stript herself to clothe her sister, and to supply materials for protecting from atmospheric waste her vast stores of coal, upon which her greatness and prosperity now so largely depend.
Página 164 - Caino/oic formations over the area, Professor Hull has arrived at the conclusion that the surface remained in the condition of dry land, while that of England was being submerged beneath the waters of the sea, over the bed of which nearly all these formations were deposited. To a certain extent, however, he leaves it an open question whether some of the Mesozoic strata which occur over the north-east of Ireland may not have been deposited over the centre and south. The amount of denudation over this...
Página 166 - Nuiumulite limestone, the greatest limestone formation in the world, was built up mainly of tha coiled shells of a special group of Foraminifera, the Nummulites. Throughout this inconceivably long lapse of time our island was more or less unsubmerged. its surface being swept by subaerial waters, and its strata carried little by little into the adjoining ocean, to form perhaps some of the strata which were being piled up over the ocean bed of the British area.
Página 232 - It will be obvious, then, that when a crystalline molecule melts, it will not merely descend in the manner already described, but capillary attraction will cause it to flow into the interstices between the adjoining molecules. The moment that it parts with the heat received, it will of course resolidify...