42 FO0RD — ON ENGLISH GEOLOGY AND GEOGRAPHY. 



found it to consist of from ninety to ninety-five per cent of the cases 

 of foraminifera, and of comminated shells. Considering that the 

 thickness of the chalk formation in England amounts to from six 

 hundred to nine hundred feet, we are hardly able to realize the 

 incalculable profusion of life which was required in order to build 

 up such a vast thickness and superficial extent of material. 



A curious instance of marine denudation occurs at Margate, 

 consisting of a detached mass of chalk about forty feet high, known 

 as the *' Fort Eock," (fig. 3.) Before this rock became isolated, 

 the sea had made an extensive excavation around it, and at last the 

 soil above it crumbled and fell. On visiting the spot this summer, 

 I found the space from the edge of the cliff to the rock on all 

 sides to be at least ten or twelve feet. This marine denudation 

 ofiers a strong contrast to atmospheric denudation, the former 

 produces jagged peaks, as in the Needle rocks at the Isle of Wight, 

 the latter results in undulating slopes, such as the North and South 

 Downs of Kent and Sussex. 



It may not be out of place here to allude to the supposed 

 former junction of England with the Continent ; the following being 

 the chief grounds for the assumption : — 



Firstly. — The close resemblance in the chalk formation of the 

 two opposite countries of England and France (which may be said 

 to be continuous,) at Dover and Cape Griznez, for example, {see 

 map.) 



Secondly, — The extreme shallowness of the water in the straits 

 of Dover — the existence of sand banks — notably the *'* Goodwin 

 Sands," where the chalk has been found by borings underlying 

 fifteen feet of sand, resting on blue clay. 



Thirdly, — The identity of the wild animals in historic times, 

 such as the vfolf, which infested both countries ; and lastly, the 

 discovery of fossil remains of the cave bear, hyaena, rhinoceros, lion. 



♦Note — An obscure tradition has come down to us, that the estates of Earl 

 Godwin, the father of Harold, who died in the year 1053, were situated here, and 

 some have conjectured that they were overwhelmed by the flood mentioned in the 

 Saxon Chronicle, sub. anno. 1099. The length of this sand bank is about ten 

 miles, by one and one-half in breadth. 



