Ch. XXIY.] coal— fossil forests IN NOVA SCOTIA. 



485 



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 heio-ht of the cliffs is 



and g, in 

 in an up- 



from 150 to 200 feet; and between d 



which space I observed seventeen trees 

 right position, or, to speak more correctly, at 

 right angles to the planes of stratification, I 

 counted nineteen seams of coal, varying in thick- 

 ness 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 g, is about 2500 feet, 

 the erect trees consisting chiefly of large Sigil- 

 larke, occurring at ten distinct levels, one above 

 the other ; but Mr. Logan, who afterwards made a 

 more detailed survey of the same line of cliffs, 

 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 14,570 feet, everywhere de- 

 void 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, however 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 Dr. 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 cliff, the sandstones and laminated shales being harder and 

 more capable of resisting the action of the waves and the weather. 

 Originally the reverse was doubtless true, for in the existing delta of 

 the Mississippi those clays in which the innumerable roots of the decidu- 

 ous cypress and other swamp trees ramify in all directions are seen to 



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



