Ch. XXIV.] COAL — FOSSIL FORESTS IN NOVA SCOTIA. 377 



In the annexed section (fig. 492), wliich I examined in July, 1842 

 the beds from c to i are seen all dipping* the same way, their average 

 inclination being at an angle of 24° S. S. W. The vertical height of the 

 cliffs is from 150 to 200 feet; and between d and (j, in which space I 

 observed seventeen trees in an upright position, or, to speak more cor- 

 rectly, atNright angles to the planes of stratification, I counted nineteen 

 seams of coal, varying in thickness from 2 inches to 4 feet. At low tide 

 a fine horizontal section of the same beds is exposed to view on the 

 beach. The thickness of the beds alluded to, between d and y, is about 

 2500 feet, the erect trees consisting chiefly of large Sigillarice, occurring 

 at ten distinct levels, one above the other ; but Mr. Logan, who after- 

 wards made a more detailed survey of the same line of clift's, found erect 

 trees at seventeen levels, extending through a vertical thickness of 4515 

 feet of strata ; and he estimated the total thickness of the carboniferous 

 formation, with and without coal, at no less than 14,5*70 feet, everywhere 

 devoid of marine organic remains.*-''^ The usual height of the buried 

 trees seen by me was from 6 to 8 feet ; but one trunk was about 25 feet 

 high and 4 feet in diameter, with a considerable bulge at the base. In 

 no instance could I detect any trunk intersecting a layer of coal, how- 

 ever thin ; and most of the trees terminated downwards in seams of coal 

 Some few only were based in clay and shale ; none of them, except 

 calamites, in sandstone. The erect trees, therefore, appeared in general 

 to have grown on beds of coal. In the underclays Stigmaria abounds. 



In 1852 Mr. Dawson and the author made a detailed examination of 

 one portion of the strata, 1400 feet thick, where the coal-seams are most 

 frequent, and found evidence of root-bearing soils at sixty-eight different 

 levels. Like the seams of coal which often cover them, these root-beds 

 or old soils are at present the most destructible masses in the whole clift', 

 the sandstones and laminated shales being hai'der and more capable of 

 resisting the action of the waves and the weather. Oiiginally the re- 

 verse was doubtless true, for in the existing delta of the Mississippi those 

 clays in which the innumerable roots of the deciduous cypress and other 

 swamp trees ramify in all directions are seen to withstand far more effec- 

 tually the undeimining power of the river, or of the sea at the base of 

 the delta, than do beds of loose sand or layers of mud not supporting 

 trees. 



This fact may explain why seams of coal have so often escaped denu- 

 dation, and remain continuous over wide areas, since the tough roots, now 

 turned to coal, which once traversed them, would enable them to resist a 

 current of water, whilst other members of the coal-formation, in their 

 original and unconsolidated state of sand and mud, would be readily re- 

 moved. 



In regard to the plants, they belonged to the same genera, and most 



of them to the same species, as those met with in the distant coal-fields 



of Europe. In the sandstone, which filled their inteiiors, I frequently 



observed fern-leaves, and sometimes fragments of Stigmaria, which had 



* Quart. Geol. Journ. vol. ii. p. 177. 



