Transactions of the Geological SocietyThe Society, 1811 |
Otras ediciones - Ver todas
Términos y frases comunes
acid alumine ammonia angle appears argillaceous bardiglione barytes beds Brongniart chalk Cheshire clay cliffs coal coast colour compact composed considerable contains Cornwall Dartmoor Forest decomposed decomposition deposited depth direction earthy eastern side elevated epidote feet felspar flint formation fossil fracture fragments Geological Society gneiss Gossan grains granite grauwacke greenstone grey gypsum Haüy height Herefordshire Beacon hill hornblende hundred indurated iron island Isle of Wight laminæ laumonite lava limestone Lode magnesia Malvern mass Memb mica miles mineral mineralogists mines molecules mountains muriat of soda nearly neighbourhood Northwich observed occurs pebbles planes porphyry precipitate primitive crystal prism pyrites quantity quarry quartz red oxyd Retrogradation rock rock-salt salt sand sandstone Schist serpentine shells Sienite slate slaty species specimens steatite stone strata stratified stratum substance Sulphate of Lime sulphuric surface texture thickness valley variety veins yards
Pasajes populares
Página 73 - ... gray limestone, with frequent veins of white crystallized carbonate of lime. From the foot of these mountains, for many leagues to the southward, there is little else than a thick fertile argillaceous soil, without a stone or a single pebble. This...
Página 67 - Mallet likewise quotes Gumilla, as stating in his Description of the Orinoco, that about seventy years ago, ** a spot of land on the western coast of this " island, near half way between the capital and Indian village sunk " suddenly, and was immediately replaced by a small lake of pitch " to the great terror of the inhabitants.
Página 184 - Plymoutb, which is situated at the foot of the mountains on the sea shore. We proceeded by a circuitous and steep route about six miles, gradually ascending the mountain, which consisted entirely of an uniform porphyritic rock, broken every where into fragments and large blocks, and which in many places was so denuded of soil as to render it a matter of astonishment how vegetation, and particularly that of the cane, should thrive so well. The far greater part of the whole island is made up of this...
Página 324 - Parkinson describes the whole island of Great Britain, as having since its completion, •' suffered considerable disturbance from some prodigious and mysterious power. By this power all the known strata to the greatest depths that have been explored, have been more or less broken and displaced, and, in some places; have been so lifted, that some of the lowest of them have been raised to the surface ; while portions of others, to a very considerable depth and extent, have been entirely carried away.
Página 185 - ... with a volcano. On the north, east, and west sides were lofty mountains wooded to the tops, composed apparently of the same kind of porphyry we had noticed all along the way. On the south, the same kind of rock of no great height, quite bare of vegetation, and in a very peculiar state of decomposition. And on the southeastern side, our path and the outlet into the ravine. The whole area thus included, might be three or four hundred yards in length, and half that distance in breadth. The surface...
Página 63 - How these crevices originate it may not be so easy to explain. One of our party suggested that the whole mass of pitch might be supported by the water which made its way through accidental rents, but in the solid state it is of greater specific gravity than water, for several bits thrown into one of the pools immediately...
Página 62 - ... us without any tremulous motion whatever, and several head of cattle were browsing on it in perfect security. In the dry season, however, the surface is much more yielding, and must be in a state approaching to fluidity, as is shewn by pieces of recent wood and other substances being enveloped in it.
Página 63 - ... in it : fish are caught in it, and particularly a very good species of mullet. The arrangement of the chasms is very singular, the sides, which of course are formed of the pitch, are invariably shelving from the surface, so as nearly to meet at the bottom, but then they bulge out towards each other with a considerable degree of conTexity.
Página 70 - ... for many leagues distant*; they might see these earthy particles deposited by the influence of powerful currents on the shores of the Gulf of Paria, and particularly on the western side of the island of Trinidad ; they might there find vast collections of bituminous substances', beds of porcelain jasper and such other bodies as may readily be supposed to arise from the modified action of heat on such vegetable and earthy materials as the waters are known actually to deposit. They would further...
Página 69 - A friend, indeed, gave me specimens of a kind of bituminous shale mixed with sand, and which he brought from Point Cedar, about twenty miles distant, and I find Mr. Anderson speaks of the soil near the pitch lake containing burnt cinders, but I imagine he may have taken for them the small fragments of the bitumen itself. An examination of this tract of country could not fail, I think, to be highly gratifying to those who embrace the Huttonian theory of the earth ; for they might behold the numerous...