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abundant according accumulations agency animals appear applied areas arrangement aspect beds bones calcareous called causes chalk chemical chiefly clay coal colour composed composition connected consists contain coral crust deposits depth developed distinct districts drift earth elevation England epoch estuaries evidence existing fact feet fishes formation forms fossil frequent geological geologist globe granite gravel heat hence igneous important indicate iron islands Italy known lakes land layers less lignites lime limestone lower marine marls masses matter mean mineral mountain nature North numerous occur ocean old red oolite operations organic origin period physical plants pleistocene portion position present recent red sandstone regarded regions remains rivers rocks sand shales shells Silurian South species stone strata structure student surface taking term tertiary thickness tion true upper varied variety vegetable volcanic whole
Página 113 - Bright ran at one time a great hazard, and suffered considerable pain from accidentally plunging one of his legs into the hot clay. * From whatever spot the sulphur is removed, steam instantly escapes ; and, in many places, the sulphur was so hot that we could scarcely handle it. From the smell, I perceived that the steam was mixed with a small quantity of sulphurated hydrogen gas.
Página 18 - In the preceding chapter we have endeavoured to explain that the object of geology is to investigate the structure of the earth, in as far as that structure is accessible to human investigation. Combining all we know of this rocky structure, from the top of the highest mountain to the bottom of the deepest mine, it forms but an insignificant film of the four thousand miles which lie between the surface and centre of the globe. This film or outer portion is spoken of as the " crust of the globe" in...
Página 113 - At the bottom of this hollow we found a caldron of boiling mud, about fifteen feet in diameter, similar to that on the top of the mountain, which we had seen the evening before ; but this boiled with much more vehemence. We went within a few yards of it, the wind happening to be remarkably favourable for viewing everv part of this singular scene.
Página 275 - Egypt, where it was largely quarried of old for the building of the Pyramids, into Asia Minor, and across Persia by Bagdad to the mouths of the Indus. It occurs not only in Cutch, but in the mountain ranges which separate Scinde from Persia, and which form the passes leading to Caboul ; and it has been followed still farther eastward into India, as far as eastern Bengal and the frontiers of China.
Página 201 - ... water ; but the case is somewhat different with beds of coal. This mineral, being chiefly composed of carbon, hydrogen, and oxygen — the same elements which enter into the composition of plants — and revealing in its mass evidence of vegetable structure, no doubt is entertained of its organic origin. But whether the plants of which it is composed were drifted down by rivers, and deposited along with layers of mud and sand in estuaries, or whether dense forests and peat-mosses were submerged,...