BITUMINOUS AND ANTHRACITIC, 465 



reconciled with the occasional occurrence of then* fronds and 

 lighter extremities. Upon no other hypothesis respecting the 

 physical condition of the region which produced the coal vegeta- 

 tion than that here imagined, can I explain the singular infre- 

 quency of fossil trunks standing on or in the coal, or account for 

 their occasional occurrence, as in the instances described by 

 Hawkshaw and Bowman. No other supposition seems to furnish 

 a cause for the absence of all traces in the coal itself, of the larger 

 parts of arborescent plants, and for their equally remarliable 

 abundance in a broken and dispersed state in the overlying 

 strata. 



Assuming such to have been the condition of the surface during 

 the tranquil periods of the accumulation of each coal-bed, we may 

 conceive the other strata to have been produced in the following 

 manner. Let us suppose an earthquake, possessing the charac- 

 teristic undulatory movement of the crust, in which I believe all 

 earthquakes essentially to consist, suddenly to have disturbed the 

 level of the wide peat-morasses and adjoining flat tracts of forest 

 on the one side, and shallow sea on the other. The ocean, as 

 usual in earthquakes, would drain off its waters for a moment 

 from the gi'eat Stigmaria marsh, and from all the swampy forests 

 which skirted it, and, by its recession, stir up the muddy soil, and 

 diift away the fronds, twigs, and smaller plants, and spread these, 

 and the mud, broadly over the surface of the bog. In this way 

 may have been formed the laminated slates, so fuU of fragmentary 

 leaves and twigs, which generally compose the immediate cover- 

 ing of the coal-beds. Presently, however, the sea would roll in 

 with impetuous force, and, reaching the fast land, prostrate every 

 thing before it. Almost the entire forest would be uprooted and 

 borne off on its tremendous surf. Spreading far inland, compared 

 with its accustomed shore, it would wash up the soil and abrade 

 whatever fragmentary materials lay in its path, and, loaded with 

 these, it would then rush out again, with iiTCsistible violence, 

 towards its deeper bed, strewing the products of the land in a 

 coarse promiscuous stratum, imbedding the fragments of the bro- 

 ken and disordered trees. Alternately swelUngand retiring, with a 

 suddenness and energy far surpassing that of any tide, and main- 



