in the Frith of Forth, 2? 



stant elevation, of between four and five fathoms, above the 

 neighbouring waters of the Mediterranean, at all times of the 

 tide. In such circumstances, if the elevated waters of the Red 

 Sea were either suddenly or slowly to assume the mean level 

 of the Mediterranean, there would be left on its deserted shores, 

 stratified or irregular deposits, containing the remains of marine 

 animals, phenomena well calculated to puzzle the advocates 

 for the universal permanency of the mean level of the ocean. 

 On the other hand, were the waters of the Mediterranean to 

 assume the mean level of the Red Sea, many tracts would be 

 inundated permanently, and others during every flood, which 

 at present are strangers to Neptune's influence. But leaving 

 the question of the permanency of the mean level of the ocean, 

 let us advert to the changes which may take place in the mean 

 level of flood tide, as applicable to the case of submarine forests. 



The mean level of the sea, at any place, may readily be 

 determined by taking the excess of the mean of the two con- 

 secutive high water marks above the intermediate low water. 

 If the ordinary neap tides of any place give a rise of ten feet 

 of water, we may here assume an elevation or depression equal 

 to five feet from the mean level. But if during spring tides, 

 at the same place, the rise be sixteen feet, these grounds will 

 be covered at the time of flood with three feet of water, which 

 the neap tides did not reach, while a corresponding portion of 

 the channel will be exposed at the time of ebb^ which at the 

 same period, in neaps, was submerged three feet. Should this 

 condition of things be altered by any change in the form of the 

 coast, or the extent and inclination of the inclined planes of 

 the channel, the progressive motion of the tide wave may be 

 altered in its velocity, direction, and elevation. If now, for 

 example, instead of sixteen feet of tide, the waters rise to forty- 

 two, as at King's Road, Bristol, the land on the neighbouring 

 shore may be covered during flood with a column of water 

 thirteen feet in height, which at a former period was beyond 

 the influence of the tide. 



If changes, such as have now been referred to, were to take 

 place on a coast covered with a forest growing near the former 

 level of high water, or with a bed of peat where a forest for- 

 merly grew, it is obvious that submergence of the spot would 

 take placp, and that a submarine forest would be formed. 



