462 ORIGIN OF THE APPALACHIAN COAL STRATA, 



alternate with the coal, have been removed by water to considera- 

 ble distances, from the spots on which they gi'cw. Proofs ai'e 

 daily increasing in favor of both opinions, namely, that some of 

 the vegetables which form our beds of coal grew on the identical 

 banks of sand, and silt, and mud, which, being now indurated to 

 stone and shale, form the strata that accompany the coal ; whilst 

 other portions of these plants have been drifted to various dis- 

 tances from the swamps, savannahs, and forests, that gave them 

 birth; particulai-ly those, that are dispersed through the sand- 

 stones, or mixed with fishes in the shale beds.* In these views of 

 Dr. Buckland, Mr. Lyell would seem to concur, as, in quoting the 

 above'passage, in his Elements, he says, that " it can be no longer 

 doubted, that both these opinions are true, if we confine our at- 

 tention to particular places." 



Another paper, on the same subject of the fossil trees, found on 

 the Manchester and Bolton railway, was read contemporaneously 

 with the last communication of Mr, Hawkshaw. The author, 

 Mr. Bowman, is of opinion, " that the theory of the subsidence 

 of the land during the carboniferous era, receives much support 

 from the phenomena presented by these fossil trees." He does 

 not deny, that plants may have been carried into the -water from 

 neighboring lands ; but he conceives it difficult to understand 

 whence the vast masses of vegetables, necessary to form thick 

 seams of coal, could have been derived, if drifted, and how they 

 could have been sunk to the bottom wdthout being intermixed 

 with the earthy sediment, which was slowly deposited upon 

 them. Another difficulty of the drift theory, he says, " is the uni- 

 formity of the distribution of the vegetable matter tlu'oughout such 

 great areas as those occupied by the seams of coal." I have 

 myself shown, that this uniformity extends even to the subordi- 

 nate divisions of each seam. Mr. Bowman believes, that the 

 coal has been formed from plants, which grew on the areas now 

 occupied by the seams ; that each successive race of vegetation 

 was gradually submerged beneath the level of the water, and 

 covered up by sediment, which accumulated till it formed another 



* Anniversary Address to Geological Society. ISII 



