296 Dr. Fleming on a [April, 



would thus collapse, and the surface of the marsh, instead of 

 remaining at its original height, would sink below the level of 

 the sea. But the escape of the water from the strata would 

 not, in such circumstances, be confined to the beds situate 

 above the low water-line. Even those occupying a position 

 considerably lower, would be influenced by the change ; for 

 the water even in such would be squeezed out, in consequence 

 of the pressure of all the matter of the strata above the low 

 water-mark, exerted during every ebb, in the expulsion of the 

 water at the lowest level, thus permitting the subsidence of the 

 strata to take place even to the lowest beds of the morass. 



In consequence of this drainage, produced by the ebbing of 

 the tide on those marshes, the original barriers of which have 

 been destroyed, there is no difficulty in accounting for the de- 

 pression of the surface of a marsh many feet lower than its 

 original level, nor in explaining the fact that Neptune now tri- 

 umphs where Sylvanus reigned, and that the sprightly Nereids 

 now occupy the dwellings of their sister Naids. 



The same explanation, now offered to account for the sub- 

 marine forest of the Tay, seems equally applicable to those of 

 Mount's Bay, Lincolnshire, and Orkney. It is warranted by 

 the effects which we have observed to have taken place in dif- 

 ferent districts of Scotland, from the artificial drainage, of 

 marshes which had formerly been lakes, and which were in a 

 condition of surface fit for the growth both of willows and 

 alders. In some cases, where the outlet of the marsh has been 

 lowered perhaps ten feet, and a ditch at this new level opened 

 through the middle of the ground, an expectation has been 

 formed that the original surface would be drained of all its 

 moisture, and brought into an arable condition. A season, 

 however, has scarcely elapsed, before this deep ditch has be- 

 come shallow, not by the silting up of the bottom, but by the 

 subsidence of the neighbouring matter, in consequence of the 

 abstraction of the water ; and the ground which was expected 

 to become fit for yielding crops of grain, has returned to a 

 condition better suited to the growth of rushes. No provision 

 in these cases had been made for the effect of subsidence. 



Before concluding this paper, I may take notice of a few 

 facts which seem to have some interest in a geological point 

 of view. 



i. One effect of the subsidence to which I have here alluded, 

 is the complanation of all the vegetable remains which occur 

 in a horizontal position, or parallel with the surface of the bed 

 of peat ; while those situate vertically retain their cylindrical 

 shape. The vegetable remains, so common in the strata accom- 

 panying coal in this country, exhibit the same appearances in 

 similar circumstances, and lead to the conclusion, that the 

 matter of the strata, at the period of deposition, was in such a 



