of Hampshire and Dorset shh-e, 25 1 



The chalk hills hi the Isle of Purbeck lie in the prolongation of 

 a line westward from the Needles : they pass through Corfe Castle, 

 and establish a separation between two troughs, or basins. The one on 

 the north has a gentle slope towards Poole Harbour, the other on the 

 south is more horizontal, extending towards the sea, on the coast of 

 which it presents a range of rather abrupt cliffs. The soil of the 

 latter is very fertile, while that of the former is completely barren, 

 and covered all over with heath. 



These hills pass under particular "names, such as Nine Barrow- 

 Downs, which I found by the barometer to be 625 feet above 

 the level of the sea ; Challer Hill, 390 ; Norden Hill, 369 ; and 

 East and West Creach. Between Challer and Norden Hills, stands 

 on the top of an hillock, the fine ruin of Corfe Castle, the height 

 of which is 207 feet. These hills consist of what is called hard 

 chalk, perhaps from the greater quantity of sand which it con- 

 tains.* 



Over the chalk lie several beds or strata of a later formation, the 

 relative age of which I shall not now presume to determine, as their 

 alternation with each other appears to be several times repeated. 



I. Flint Gravel in loose Sand^ or Loam, 



This is the formation which prevails chiefly on quitting London, 

 in travelling to the south-west. On the road to Southampton by 

 Bagshot, Farnham, &c. I have traced it as far as to New Alresford ; 



* It would be interesting to trace the characters of this rock more distinctly, anJ 

 especially to ascertain whether it inclosed fossils which are not to be found in the com- 

 mon and sojt variety, Chaux ecrivantc of the French, 



2i2 



