466 ORIGIN OF THE APPALACHIAN COAL STRATA, 



tained probably in this state of tempestuous oscillation, by fresh 

 heavings of the crust, the waters would go on spreading a suc- 

 cession of coajser or finer strata, and entombing at each inunda- 

 tion a new portion of the floating forest. Upon the dying away 

 of the earthquake undulations, the sea, once more restored to 

 tranquillity, would hold in suspension at last, only the most finely 

 subdivided sedimcMitary matter, and the most buoyant of the 

 uptorn vegetation, that is to say, the argillaceous particles of the 

 fire-clay, and the naturally floating hollow stems of the Stigmarice. 

 These would at last precipitate themselves together, by a slow 

 subsidence, and form a uniform deposit, exhibiting but few traces 

 of any active horizontal cuiTcnts, such as would arise from a 

 drifting into the sea from rivers. The chief portion of the coarser 

 fire-clay would settle first, and then the more impalpable particles, 

 in company with the stems and leaves of the Stigmarice. Thus 

 we may account for the constant reproduction of the peculiar soil 

 of the coal-seams, and for the preservation, particularly in its 

 upper layers, of the Stigmaria plant ; the simple consequence of 

 the final subsidence of these materials, being the production of the 

 necessary substratum of another coal-marsh. The marine savan- 

 nahs becoming again clothed with their spongy matting of Stig- 

 marice^ and fringed on the side towards the land with wet forests 

 of arborescent Ferns, all the essential conditions and changes that 

 constituted this wonderful cycle in the statical and dynamic pro- 

 cesses belonging to each seam of coal, and the beds enclosing it, 

 would be completed, and ready to be once more renewed. In 

 the hypothesis now proposed, the great relative buoyancy of the 

 Stigmarice is considered, and we have the testimony of Dr. Buck- 

 land and others, to show that it was a plant admirably fitted by 

 its structure, to float upon the surface of the water. 



Though the train of actions here imagined enables us to recon- 

 cile the indications afforded by the coal-beds, of periods of pro- 

 longed tranquiiUty, with the evidences of violent aqueous currents, 

 as shown in the composition of the coarser mechanical rocks ; 

 yet a complete theory of the coal-formation calls for the introduc- 

 tion of other considerations connected with the existence and 

 positions of strata, derived from chemical and organic agencies, 



