in the Frith of Forth, 25 



on which the Lincolnshire submarine forest reposes, con- 

 sidered its present depressed line, as the effect of subsidence 

 suddenly acting by means of an earthquake, and this sub- 

 sidence he defined to be the natural consequence of gravity, 

 slowly, though perpetually, operating in soft ground. 



Professor Play fair, in his invaluable illustrations of the 

 ** Huttonian Theory,*" regards the subsidence, which brought 

 the forest within the reach of the tide, as constituting a part 

 of that alternate depression and elevation of the surface, which, 

 in his opinion, probably extends to the whole mineral kingdom- 



In the paper in the Transactions of the Royal Society of 

 Edinburgh, already referred to, I endeavoured to explain the 

 present depressed state of submarine forests, by supposing that 

 their present site had formerly been a lake, which in suc- 

 cession had passed into a marsh and wood ; that the barrier 

 having been removed by the encroachments of the sea, a 

 partial drainage took place, followed by subsidence and sub- 

 mergence. 



In the '« Annals of Philosophy," for November 1823, p. 344, 

 Professor Henslow endeavoured to shew, *' that an increase of 

 elevation, above the original surface of the ocean, has actually 

 taken place," by water added to the earth at the time of the 

 Deluge, by means of a comet : that in consequence of this 

 elevation, beds of peat, containing vast numbers of trees, are 

 now found in some situations, extending under the bed of the 

 ocean. 



In the same work, for April 1825, p. 255, Professor Sedg- 

 wick, without excluding the occasional operation of several 

 of those agents which have been already referred to, has 

 offered the following explanation of the phenomena of sub- 

 marine forests. — •^' The mean elevation of the sea about every 

 part of our coast, is unquestionably constant ; but the actual 

 level of high-water at any given place, is dependent on the 

 velocity and direction of the tidal currents, the contour of the 

 coast, and a number of circumstances which are entirely local. 

 In proof of this assertion, it is only necessary to appeal to the 

 fact, that in extensive bays and estuaries, the sides of which 

 gradually diverge towards the open sea, the tides occasionally 

 rise (through the operation of a common hydrostatical law) 

 to an elevation which is many times greater than the rise of the 



