ROOM III. GEOLOGY OF THE S. E. OF ENGLAND. 211 



South-eastern; but on the South-western the Chalk and the 

 Tertiary strata only are exposed. 



The Chalk, as is well known, constitutes the predominant 

 geological feature of this part of England. The Upper or 

 White Chalk rises into chains of hills called Downs, which are 

 remarkable for their smooth and undulated outline, and form 

 a well-defined geographical boundary. The southern range 

 extends from Hampshire through Sussex to the sea-coast, 

 terminating in the bold promontory of Beachy Head; the 

 northern passes from Hampshire, through Surrey and Kent 

 to the British Channel, and ends in the line of cliffs near 

 Dover. 



The lower Cretaceous strata compose ranges of hills less 

 uniform in elevation and extent, which skirt the inner margin 

 and escarpments of the Downs, and in some parts of Surrey 

 and Western Sussex, attain an altitude equal to that of any 

 portion of the North or South Downs. Leith Hill, in Surrey, 

 is nearly 1,000 feet above the level of the sea. 1 



PHYSICAL GEOGRAPHY OF THE COUNTRY. The Wealden 

 deposits fill up the whole area between the North and 

 South Downs, and are bounded on the west by the cretaceous 

 strata of Hampshire, and on the east by the British Channel ; 

 they form the sea-coast from Pevensey in Sussex to Hythe in 

 Kent. 



Looking down upon the Wealden from any of the heights 

 that command a view across the district, and of the distant 

 boundary of chalk downs as for example from Leith Hill, 

 or from the summit of the escarpment of the North Downs, 

 near Reigate the observer might suppose that these fresh- 

 water sediments occupy a depression or basin on the surface 

 of the chalk, and that the strata of the North and South 

 Downs extend under the whole of the deposits in the inter- 

 vening area. 



GEOLOGY OF THE SOUTH-EAST OF ENGLAND. A slight 

 examination of the natural sections of the respective strata 

 where their relative position can be ascertained, is, how- 

 ever, sufficient to show the incorrectness of this hypothesis, 



1 For details, vide a Memoir by the Author, "On the Geological 

 Structure of the Country seen from Leith Hill," in the County History 

 of Surrey; published by Mr. Ede of Dorking. 



