of Devonshire and Cornwall. 95 



which this formation lies in France and in England, some persons 

 have been led to consider it as one and the same, and consequently 

 to conclude that the British channel, which separates these parts 

 which are now opposed to each other, has been formed after the 

 chalk had been deposited. I shall not however enter upon the dis- 

 cussion of the merits of that opinion, which if examined in detail, 

 would offer several difficulties, as I do not think that it is necessary 

 to adopt it, in order to account for the facts which present 

 themselves. 



One of the distinctive characters of this formation, i? the dispo- 

 sition of the flint in beds or layers, nearly parallel to each other, 

 though at unequal distances, so that whatever be the shape of the 

 country at the surface, whether it be hilly or flat, the beds of flint 

 preserve a nearly uniform parallelism with the surface of the ground j. 

 this is tolerably well seen in Dorsetshire, a county, the outline of 

 which is very undulated. This kind of hilly ground is known in: 

 England by the name of downs. In Hampshire, in the western part 

 of it especially, there are elevated plains, and occasional depres- 

 sions, but these last are not sufficiently deep nor do they succeed 

 to the former so rapidly as to entitle that district of country to the 

 name of downs. 



Flints near their original situation do not always appear in the 

 form of pebbles, but often in masses of a more or less considerable 

 size, and of a shape sometimes flatted and irregular. It is chiefly in 

 alluvial ground formed of a slightly aggregated gravel, that flints are 

 found in the state of pebbles, of different sizes, according to the 

 friction they have undergone, and consequently, according to the 

 distance from which they have been brought : hence, the individual 

 pebbles of which gravel consists, become i-n general smaller and 

 smaller as they approach the sea. 



