376 



COAL — OBLIQUE FOSSIL TREES. 



[Ch. XXIV. 



S2 



in 1830, when all the strata had been removed from one side. The 

 beds which remained were so unaltered and undisturbed at the point of 

 junction, as clearly to show that they had been tranquilly deposited 

 round the tree, and that the tree had not subsequently pierced through 

 tbem, 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 fourteen 

 of them might be reckoned in the thickness of an 

 inch. Some of these thin layers were dark, and 

 contained coaly matter ; but the lowest of the in- 

 tersected 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 j^art, calca- 

 reous.* It is also clear, that the lapidifying matter 

 was not introduced laterally from the strata through 

 which the fossil passes, as most of these were not 

 calcareous. It is well known that, in the Mississippi 

 and other great American rivers, where thousands of 

 trees float annually down the stream, some sink 

 with their roots downwards, 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. Mr. Hugh 

 Miller mentions four other huge trunks exposed in 

 quarries near Edinburgh, which lay diagonally across 

 the strata at an angle of about 30°, with their lower 

 or heavier portions downwards, the roots of all, save one, 

 rubbed off by attrition. One of these was 60 and an- 

 other 70 feet in length, and from 4 to 6 feet in diameter. 

 The number of years for which the trunks of trees, 

 when constantly submerged, can resist decomposition, 

 is very great ; as we might suppose from the durability 

 of wood, in artificial piles, permanently covered by water. 

 Hence these fossil snags may not imply a rapid accumu- 

 lation of beds of sand, although the channel of a river or 

 part of a lagoon is often filled up in a very few years. 



Nova Scotia. — One of the finest examples in the 

 world of a succession of fossil forests of the carboniferous 

 period, laid open to view in a natural section, is that 

 seen in the lofty cliffs, called the South Joggins, bor- 

 dering the Chignecto Channel, a branch of the Bay of 

 Fundy, in Nova Scotia.f 

 * See figures of texture, Witbam, Foss. Yeget. pi. 3. 

 f See Ly ell's Travels in K America, vol. ii. p. 179 ; and Dawson, Geol. Journ. No. 37. 



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