BITUMINOUS AND ANTHRACITIC. ' 463 



dry surface for the growth of another series of trees and plants, 

 and that the submergences and accumulations took place as many 

 times as there are seams of coal.* 



In reviewing the above facts and opinions, Dr. Buckland con- 

 ceives, that a luxuriant growth of marsh plants, as Calamites, Lepi- 

 dodendra, Sigillaria, &c., may have formed a superstratum of coal, 

 resting on a substratum of the same, composed exclusively of re- 

 mains of StigmarUc ; and in accounting for the marine and fresh- 

 water strata alternating with the coal-beds, he appeals to the 

 intermitting and alternate processes of subsidence, drift, and veg- 

 etable growth.f 



The above summary of the recent researches and speculations 

 of geologists, conveys, I believe, a coiTect view of the state of 

 opinion at the present time, in relation to the interesting problem 

 of the origin of the coal strata. I may now venture to advance 

 my own explanation of the phenomena, and to indicate wherein 

 I differ from the able authors I have cited. The several hypothe- 

 ses proposed, do not attempt to account for some of the most re- 

 markable relationships among the strata, such as the extraordinary 

 frequency, beneath the coal-beds, of the Stigmaria clay, the very 

 general occurrence of laminated slates immediately above the 

 seams, and the singular contrast which these underlying and 

 overlying rocks present, in the variety and condition of the im- 

 bedded vegetable remains. Nor do they explain satisfactorily 

 why the coal itself contains so few traces of the forest trees of the 

 period, either in a prostrate or erect position ; while their broken 

 stems are mingled with the fragmeiitary parts of the Stigmaria, 

 in more or less abundance, in all the coarser rocks. Perhaps the 

 following hypothesis will account for the phenomena. 



Let us imagine the areas now covered with the coal-formation, 

 to have possessed a physical geography, in which the principal 

 feature was the existence of extensive flats, bordering a continent, 

 and forming the shores of an ocean, or some vast bay, outside of 

 which was a wide expanse of shallow but open sea. Let us now 



* Bowman in Proceedings Geological Society, London, No. 69. 

 t Anniversary Address to Geological Society, 1841. 



