VOL. LXXXIX.] PHILOSOPHICAL TRANSACTIONS. 483 



to be the same as that in which they grew. It would have been impossible for any 

 of these trees and shrubs to vegetate so near the sea, and below the common level 

 of its water : the waves would cover such tracts of land, and hinder any vegetation. 

 We cannot conceive that the surface of the ocean has ever been lower than it now is> 

 on the contrary, we are led by numberless phenomena to believe, that the level of 

 the waters in our globe is much below what it was in former periods ; we must 

 therefore conclude, that the forest here described grew in a level high enough to 

 permit its vegetation ; and that the force, whatever it was, which destroyed it, 

 lowered the level of the ground where it stood. 



There is a force of subsidence, particularly in soft ground, which, being a natural 

 consequence of gravity, slowly though perpetually operating, has its action some- 

 times quickened and rendered sudden by extraneous causes, for instance, by earth- 

 quakes. The slow effects of this force of subsidence have been accurately remarked 

 in many places ; examples also of its sudden action are recorded in Almost every 

 history of great earthquakes. The shores of Alexandria, according to Dolomieu's 

 observations, are a foot lower than they were in the time of the Ptolemies. Donati, 

 in his natural history of the Adriatic, has remarked, seemingly with great accuracy, 

 the effects of this subsidence at Venice ; at Pola, in Istria ; at Lissa, Bua, Zara, 

 and Diclo, on the coast of Dalmatia. In England, Borlase has given, in the Phil. 

 Trans, vol. 48, p. 62, a curious observation of a subsidence, of at least 1 6 feet, in 

 the ground between Sampson and Trescaw islands, in Scilly. The soft and low 

 ground between the towns of Thorne and Gowle, in Yorkshire, a space of many 

 miles, has so much subsided in latter times, that some old men of Thorne affirmed, 

 " that whereas they could before see little of the steeple of Gowle, they now see the 

 churchyard wall."* The instances of similar subsidence which might be mentioned, 

 are innumerable. 



This force of subsidence, suddenly acting by means of some earthquake, seems 

 the most probable cause to which the actual submarine situation of the forest we 

 are speaking of may be ascribed. It affords a simple easy explanation of the matter; 

 its probability is supported by numberless instances of similar events ; and it is not 

 liable to the strong objections which exist against the hypothesis of the alternate de- 

 pression and elevation of the level of the ocean ; an opinion which, to be credible, 

 requires the support of a great number of proofs, less equivocal than those which 

 have hitherto been urged in its favour, even by the genius of a Lavoisier.-f- 



The stratum of soil, l6 feet thick, placed above the decayed trees, seems to re- 

 move the epoch of their sinking and destruction, far beyond the reach of any histo- 

 rical knowledge. In Caesar's time, the level of the North Sea appears to have been 

 the same as in our days. He mentions the separation of the Wahal branch of the 

 Rhine, and its junction to the Meuse ; noticing the then existing distance from 

 that junction to the sea ; which agrees, according to D'Anville's inquiries, J with 



* Gough's edition of Camden's Britannia, t. 3, p. 35. f Mem. de 1'Acad. de Paris, 1789, p. 351. 



— — * D'Anville Notice des Gaules. p. 461, — Orig. 



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