19 



with the artificial drainage and navigation of the country. It is 

 almost certain that in such a state ot things the tides cannot rise 

 to the exact level which they reached in ancient times ; and the 

 change will, I think, be precisely of that kind which will explain 

 the appearance of submarine forests in many places bordering 

 upon the Wash. If through a combination of causes such as 

 have been mentioned, the tides on any part of the coast rise to a 

 level only a few feet higher than they did in ancient times, the 

 whole difficulty we have been considering at once vanishes. 



The conclusions which have been deduced from a considera- 

 tion of certain facts exhibited on the coast of Lincolnshire, may 

 be extended to every country which is similarly circumstanced; 

 and it seems probable that an actual change in the height of the 

 tides produced by a change in the contour of the neighbouring 

 coasts, is among the most general and efficient causes which 

 have produced the phenomena of submarine forests. By this 

 assertion it is, of course, never intended to exclude other agents 

 from their proper share in producing the phenomenon. Forest 

 trees may have grown in many low tracts bordering on the sea 

 while they have been protected from the flood-tides by artificial, 

 and sometimes, perhaps, by natural embankments ; and in sub- 

 sequent ages the embankments may have failed, and the forests 

 may have been submerged by a consequent incursion of the 

 waters. Fen lands, after being drained and brought under cul- 

 tivation, may have undergone a natural subsidence, and on that 

 account have been exposed to the chance of subsequent inun- 

 dations. This at least was Deluc's opinion, founded on obser- 

 vations made in various parts of Holland. Lastly, large tracts 

 of low alluvial land may (after the natural destruction of the bar- 

 riers by which they were held in) be transferred by a slide to a 

 lower level ; and in that way productions once out of the reach 

 of the high tides may become exposed to their constant attacks. 

 By the gradual operation of such causes as have been enume- 

 rated, the existence of submarine forests may in most instances 

 be satisfactorily explained without the intervention of earth- 

 quakes or other irregular disturbing forces. 



The phenomena above described (viz. the existence of land 

 productions below, and of marine productions above the level of 

 high-water) are after all things sui generis, which are confined to 

 a Bmall part of the coast; and, however interesting in themselves, 

 throw no light whatever on the general classification of alluvial 

 and diluvial deposits. 



( To be continued.) 



