ON A SUBMARINE FOREST IN THE FRITH OF TAY. 425 



" ed, the same cause which occasioned the first has room to 

 " revive, and renew its struggles, and to repeat its desolations 

 " and terrors ; which is most probably the case of Lisbon." 

 Phil. Trans. 1757, p. 52. 



The views of Dr Borlase, in reference to this depression of 

 the ground, in consequence of earthquakes, was evidently in- 

 fluenced by the curious observations which he had formerly 

 made on the subsidence of some places at the Scilly Islands, 

 as stated, Phil. Trans, vol. xlviii. p. 62; and other observers 

 may be led to form the same opinion, especially if the sin- 

 gular sinking of the cliff at Folkstone, about forty feet, even in 

 the absence of an earthquake, be taken in consideration. See 

 Phil. Trans. 1786, p. 220. 



Dr Correa de Serra also ascribes the depressed position 

 of the submarine forest of Lincolnshire to the force of sub- 

 sidence, aided by the sudden action of earthquakes. " There 

 " is a force of subsidence (he says), particularly in soft 

 " ground, which, being a natural consequence of gravity, slow- 

 " ly, though perpetually operating, has its action sometimes 

 " quickened and rendered sudden by extraneous causes, for 

 " instance, by earthquakes." " This force of subsidence, sud- 

 " denly acting by means of some earthquake, seems to me the 

 u most probable cause to which the actual submarine situa- 

 " tion of the forest we are speaking of may be ascribed. It 

 " affords a simple easy explanation of the matter ; its proba- 

 " bility is supported by numberless instances of similar 

 «« events." Phil. Trans. 1799. 



Professor Playfair, when contemplating the phenomena of 

 the Lincolnshire submarine forest, rejected the explanation 

 offered by Dr Correa de Serra, and availed himself of some 

 of the peculiar assumptions of the Huttonian Theory of the 

 Earth. " The subsidence (he says) however, is not here 



3 h 2 " understood 



