in the Frith of Forth. 29 



in the paper already referred to, there occurs a considerable 

 difficulty with respect to the barriers of those lakes which pre- 

 viously occupied the place of the forests and the silt of which 

 at present forms their subsoil. Dr. Correa de Serra justly ob- 

 serves that •* an exact resemblance exists between maritime 

 Flanders and the opposite low coast of England, both in point 

 of elevation above the sea and of internal structure and arrange- 

 ment of their soils.'* To me it does not seem extravagant to 

 connect the phenomena presented by the modern strata of both 

 shores, and to lead the fancy back to that period when the 

 space now occupied by the German Ocean was a fresh -water 

 lake. To maintain such a state of things we have only to ima- 

 gine the continuity of the chalk beds of Dover and Calais, and 

 those of a similar sera of Sutherland and Jutland. The last 

 is indeed no slight stretch of the imagination, and, in the 

 absence of other proof, might deserve to be denominated ex- 

 travagant. But in this neighbourhood there are other evi- 

 dences indicating that fresh-water lakes existed where the sea 

 now prevails, in the lacustrine silt over which it flows ; and 

 there are terraces and hills of fresh- water gravel which point 

 out the former existence of sea-ward barriers of which not a 

 trace remains. If such a lake ever existed, as the magnificent 

 one alluded to, its drainage, and the consequent subsidence of 

 its marshy margin, might serve to explain several interesting 

 phenomena, as well as the character of those submarine forests 

 which now present themselves beFow the mean level of the sea. 

 But 1 fear that this notice has already extended too far to per- 

 mit me to enlarge any farther on such topics. 



February 15, 1830. 



