. Elements of geology. Geology. 260 LYELL'S ELEMENTS OF GEOLOGY. Hate of Deposition of the Coal Strata. Inclined position of a fossil tree cutting through horizontal beds of sandstone, Craigleiih quarry. Edinburgh. Angle of inclination from a to h 27°.. coal, forming a striking contrast in colour with the white quartzose sandstone in which it lay. The an- nexed figure represents a portion of this tree, about 15 feet long, which I saw exposed in 1830, when all the strata had been re- moved from one side. The beds which remained were so unaltered and undis- turbed at the point of junction, as cl
. Elements of geology. Geology. 260 LYELL'S ELEMENTS OF GEOLOGY. Hate of Deposition of the Coal Strata. Inclined position of a fossil tree cutting through horizontal beds of sandstone, Craigleiih quarry. Edinburgh. Angle of inclination from a to h 27°.. coal, forming a striking contrast in colour with the white quartzose sandstone in which it lay. The an- nexed figure represents a portion of this tree, about 15 feet long, which I saw exposed in 1830, when all the strata had been re- moved from one side. The beds which remained were so unaltered and undis- turbed at the point of junction, as clearly to show that they had been tranquilly depo- sited round the tree, and that the tree had not subsequently pierced through them, while they were yet in a soft state. They were composed chiefly of siliceous sandstone, for the most part white; and divided into laminae so thin, that from six to four- teen of them might be reckoned in the thickness of an inch. Some of these thin layers were dark, and contained coaly mat- ter; but the lowest of the intersected beds were calcareous. The tree could not have been hollow when imbedded, for the interior still preserved the woody texture in a perfect state, the petrifying matter being, for the most part, calcareous.^ It is also clear, that the lapidifying matter was not introduced late- rally from the strata through which the fossil passes, as most of these were not calcareous. It is well known that, in the Missis- sippi and other great American rivers, where thousands of trees float annually down the stream, some sink with their roots down- wards, and become fixed in the mud. Thus placed, they have been compared to a lance in rest; and so often do they pierce through the bows of vessels which run against them, that they render the navigation extremely dangerous. But the vertical coal-plants did not always retain their roots. Perhaps they sank with their larger end downwards, because the specific gravity of the wood may have been gre
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Keywords: ., bookauthorlyellcharlessir17, bookcentury1800, booksubjectgeology
