1824.] below the Chalk, 8>x. 369 



to form a continuous valley, from the west of Atherfield rocks 

 through Brixton, and thence to Brook ; and from this depression 

 the ground rises gradually on all sides to the coast, so as to 

 resemble a portion of a flattened dome. A similar structure, 

 and the same succession of beds, may be seen on the other side 

 of the island, from the heights above Bonchurch, eastward to 

 Culver ; but the sands there occupy a much smaller space, and 

 form only an insulated patch, surrounded by the weald clay, 

 which passes into the interior from the shore beneath the 

 village of Sandown, and in returning to the sea divides the 

 cliff, about midway between the fort and Culver, and imme- 

 diately on the west of Red-cliff. The whole of the intermediate 

 tract between the two chalk ranges, from New Church, through 

 Godshill, and thence to Kingston, is probably occupied by the 

 Green-sand alone, — except perhaps in the deepest places, where 

 the weald clay may appear in the beds of the streams. 



III. The strata then, of which the south of the Isle of Wight 

 consists, are the following : — 



Names given by Mr. Webster. 



1. Chalk Chalk and chalk marl. 



2. Sandstone, with chert, &c. (Firestone) Green sand. 



3. Clay (of the underdid 1 ) (Gault) .... Blue marl. 



4. Sand,with various fossils (Greenland) " 



5. Clay (of the wealds and Tetsworth) I Ferruo . mous sands 



6. Sands (of Hastings) the lowest beds ' 



in the island 



I cannot give a full description of these beds, but the 

 following observations may assist for the purpose of recog- 

 nising them, where the order is less distinct than in the Isle of 

 Wight : more detailed sections, accompanied by specimens, 

 have been laid before the Geological Society. The shells which 

 I shall mention have been named by Mr. Sowerby, who will give 

 figures in his Mineralogical Conchology, of such as have not 

 already appeared. 



Firestone. — This formation is obviously of such importance 

 as to require a distinct name ; and it seems better to adopt that 

 which I have given, than to retain the term green-sand employed 

 by Mr. Webster, which has been almost universally appropriated 

 to a lower stratum ; the Firestone, of Ryegate iicc. exhibiting 

 a sort of average character, between that of the lower part of 

 the Cambridge Clnnch, and of the greener beds of the Isle of 

 Wight. The formation in the latter place has been so well de- 

 scribed by Mr. Webster, (p. 140.) that 1 need only mention the 

 importance of extending the list of its fossils, for the purpose of 

 more completely distinguishing it from the lower beds of the 

 green sand, with which it has been frequently confounded. 



Neio Series, vol.. v in. 2 B 



