Theories of Formation of Coal. 99 



The formation of coal-measures like the above, and of all 

 others where there is evidence that the vegetable matter was 

 not drifted to the place it now occupies, but must have grown 

 •on the spot, is then accounted for, by supposing, that the land 

 sank below the level of adjoining water ; that gravel, sand, 

 and mud were washed down from the land that did not sink, 

 and formed layers of clay and sandstone over the submerged 

 forest, either in sufficient quantity to rise to the surface of 

 the water and form land for the next forest, which was sub- 

 merged in its turn, or that a contrary internal movement 

 took place, which again raised the submerged land ; and that 

 for every seam of coal, one above the other, a similar series 

 of changes must have taken place. It is to this oscillatory 

 movement that Mr Lyell ascribes the formation of the above 

 remarkable phenomena in the Bay of Fundy, and others of 

 a like nature. 



At first sight, both theories seem well-founded, when ap- 

 plied to the particular coal-fields described ; and it is possible 

 that these eminent and experienced geologists may be of 

 opinion that both are true, as applied to different situations. 

 But I see great difficulties to the full acceptance of either, 

 in many of the phenomena which, on a close examination, 

 we find coal-fields generally present. As examples, I will 

 call your attention to two sections that have very recently 

 been published ; the one a section of the western part of the 

 South Welsh Coal-Field, included in the valuable series lately 

 issued from the office of the Geological Survey of Great Bri- 

 tain, the work of W. E. Logan, Esq., a Fellow of this Society, 

 so well known to us as an excellent observer, and as inti- 

 mately acquainted with coal-fields, and who was formerly 

 attached to that Survey ; the other is entitled a " Section of 

 the No via Scotia Coal-Measures, as developed at the Jog- 

 gins, on the Bay of Fundy, in descending order, from the 

 neighbourhood of West Rugged Reef to Minudie, reduced to 

 vertical thickness." It is also the work of Mr Logan, who 

 is now employed by the Government of Canada to make a 

 Geological Survey of that country, and is contained in his 

 report to the late Governor Sir Charles Metcalfe, and trans- 

 mitted by the Governor to the Legislative Assembly. And 



