252 Mr. Webster ofi the Strata lying over the Chalk. 



The strata are situated in the department of the lower Rhine, in the 

 mountains of St. Sebastian, one of the lowest in the chain of theVosges. 



The great quantities of white calcareous marl with freshwater 

 shells, so frequently found on the top of the London clay, and en- 

 veloping the bones of land animals, would seem to denote a marshy 

 country, and one containing a great deal of stagnant water. This 

 seems to have been the first state of the country at the time of the 

 emerging of the land after the deposition of the blue clay. 



In this marl and over the clay is the first appearance of land 

 quadrupeds, agreeing in this respect with the same observation made 

 by Cuvier on the calcaire grossier, above which in France their 

 remains are found in abundance. 



The changes preceding or accompanying the upper marine for- 

 mation perhaps destroyed part of the superior strata, and deposited 

 many of those extensive beds of shells now to be found over the 

 London clay. But the nature of the last original marine strata of 

 this country, the revolutions they may have undergone even in the 

 ancient state of the earth, are circumstances which can probably no 

 longer be explained. 



Whether the existence of the second freshwater formation in the 

 Isle of Wight will admit of the same solution as has been proposed 

 for the first, must be left, like it, undecided : but it appears to have 

 taken place in a lake possessing the utmost tranquility. 



Upon the whole it must be allowed that the points of resem- 

 blance which have been enumerated between the superior strata of 

 this part of our island and the adjoining part of the continent, are 

 too numerous and striking to be the result of accidental causes, and 

 demonstrate in the clearest manner that they were occasionally sub- 

 jected to the same general laws. Whilst at the same time the 

 variations are so considerable, that the effects of these causes appear 

 to have been much modified by local circumstances. 



