182 Dr. FiTTON on the Strata below the Chalk. 



The Isle of Wight. 



(91.) The general relations of the strata on the southern coast of the Isle 

 of Wight, have been described by Mr. Webster* with so much ability, that 

 little was left to succeeding observers but the task of filling up details, and of 

 supplying some facts respecting the lower members of the series, which did 

 not fall within the immediate scope of his inquiries. Having already pub- 

 lished a general account of these lower strata in another place|, I shall here 

 give some farther observations on what is commonly called ''the back," or 

 south side, of the island. 



(92.) As the chalk passes entirely across the Isle of Wight, nearly from 

 west to east, in a narrow ridge composed of vertical strata, and again 

 invests a portion of the southern promontory of the island, with a cap of 

 almost horizontal beds, at present detached from the central ridge and ex- 

 tending nearly to the sea, — the result is, that two very distinct sections of the 

 vertical chalk and inclined strata beneath it are disclosed upon the shore, 

 at the extremities of the central range ; and again, two other sections, in 

 which the same strata are prolonged from beneath the horizontal chalk, on 

 each side of the promontory that projects towards the south, so as to meet 

 the continuation of those which rise from the middle of the island, and with 

 them form very flat curves. The coast thus exhibits a series of .sections of 

 almost unequalled richness and variety : and though the general charactersof 

 the strata are well known, there is still quite enough to be learned in this 

 most interesting geological region, to repay such detailed researches as have 

 been of late years devoted to some other portions of England, but which those 

 only who reside near the place can carry on with complete success. 



(93.) The Section, PI. X. a. No. 7. (which is on the scale of the Ord- 

 nance Survey), shows the general order of the strata on the southern coast of 

 the island, and, with the aid of a good map J, will enable the reader to follow 

 the ensuing detail. In the lower of the two lines, the heights are on the same 

 scale as the horizontal distances. 



Chalk, — The relations of the lowest beds of the chalk are best seen, on the west, at Compton 

 Bay ; and on the east, in the cliffs under Bembridge Down ; both sections exliibiting admirably 

 the passage from the white chalk to the Upper green-sand. Large portions of the chalk are pre- 



* "Letters to Sir Harry Englefield," &c. 4to. 1816. 



t " Annals of Philosophy," Nov. 1824, p. 367, et seq. 



+ The map annexed to Mr. Webster's letters, in Sir H. Englefield's volume, (Plate 48.) though 

 less accurate geometrically, gives many names, and much information useful to the Geologist, 

 which are not to be found in the Ordnance Survey. 



