[ 452 ] 

 LXVI. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from p. 382.] 



Nov. 8, 1865.— W. J. Hamilton, Esq., President, in the Chair. 



r |PHE following communications were read : — 

 -*- 1. " On the Submarine Forest-beds in Porlock Bay." By R. 

 A. C. Godwin-Austen, Esq., F.R.S., For. Sec. G.S. 



The submerged forest of Porlock Bay has been briefly noticed by 

 Sir H. De la Beche, but has not been sufficiently described, inasmuch 

 as it illustrates more clearly than the larger forests of Bridgewater 

 Level or Swansea Bay the nature and order of the oscillations of 

 small amount which have taken place at times shortly antecedent to 

 the present, and which were classified by the author in this paper as 

 follows : — (1) The formation of an angular detritus and its accumu- 

 lation at lower levels ; at this period the land was at its highest 

 relative elevation. (2) Forest-growths established on the detrital 

 beds just mentioned ; the stumps of these forest-trees, some of which 

 are of large size and great age, at present constitute the Submerged 

 Forest. (3) Accumulation of freshwater mud (resulting probably 

 from a depression of the land), by which the trees were killed. 

 (4) Surface of water-plant growths on the mud-deposit, or nearly 

 dry surface, on which the trees fell. (5) Area depressed below the 

 sea-level, and sea-mud with Scrobicularice deposited. (6) Conver- 

 sion of the surface into meadow-land at the level of the highest 

 springs of the present day, caused by re-elevation. (7) Shingle, 

 heaped up on the meadow-land, and showing that the most recent 

 change has been one of slight depression. 



This succession of changes corresponds with that of numerous 

 other localities in the West of England ; and as Mr. Godwin-Austen 

 considered the angular detritus (1) to be the result of subaerial 

 weathering, which took place over this area approximately contem- 

 poraneously with the deposition of the Boulder-formation in more 

 northern districts, this Porlock submerged forest seems to fix a rela- 

 tive date for the rest — namely, as being subsequent to the Glacial 

 Period. By this means, also, a relative date is arrived at for many 

 of the raised beaches in the West of England, as of that near Baggy 

 Point, where the old sea-bed, at an elevation of 60 feet, is covered 

 by an enormous accumulation of angular debris ; these raised beaches 

 may therefore correspond in time to certain marine deposits, which, in 

 Norfolk and Suffolk, next underlie the great " Boulder Formation." 



2. " On the Marine Origin of the ' Parallel Roads ' of Glen Roy." 

 By the Rev. R. Boog Watson, B.A., F.G.S. 



After a brief description of these well-known " Roads," the author 

 gave an analysis of the two principal theories that have been started 

 to account for their formation — namely, the Ice-dam theory and the 

 Marine theory. With regard to the first theory, Mr. Boog Watson 

 stated his opinion that, although it has some strong points, especially 

 in respect of the coincidence between the levels of the " Cols " at 

 the glen-heads and those of the " Roads," yet on the other hand 



