1 822.] Geology of the Isle of Wight, S^x, 347 



observe, that the mineralogical character of the calcareous beds 

 in that part of the coast ahnost coQipels us to unite them with 

 the similar beds near Brading harbour and White chfF Bay. 



It would be improper not to mention in this place the appear- 

 ance of the lower freshwater beds between Yarmouth and Gurnet 

 Point. In that part of the coast they generally lose the appear- 

 ance of an indurated calcareous marl, and pass into masses of 

 stiff clay or argillaceous marl, which are not unfrequently of a 

 bright green colour. Many of these green beds preserve their 

 continuity for a great extent ; and their order of superposition 

 is beautifully traced out wherever the lower part of the cliff is 

 not masked by the rubbish which is perpetually descending from 

 the upper argillaceous beds. It seems impossible to avoid 

 arranging them with some of the rocks we have been describing. 

 Perhaps they may be the representatives of the highest part of 

 the loioerfresJtwater formation which is so frequently associated 

 with beds of argillaceous marl. In this instance we may consider 

 the calcareous portion of the formation to have been almost 

 excluded by its associate. These beds of argillaceous marl are 

 no where more perfectly exposed than in a part of the coast 

 between Yarmouth and Hampstead Cliff, which is covered at 

 high water; for in consequence of a very unusual angle of incli- 

 nation towards the south, they are brought out one from under 

 another in a long succession. The whole formation is subdivided 

 by almost innumerable layers of fossil shells which follow the 

 planes of stratification. The beautiful preservation even of the 

 minutest characters both of the bivalves and of the univalves, 

 and still more, their arrangement in distinct families, afford a 

 proof not short of demonstration, that the whole system has 

 originated in a tranquil deposition. Unfortunately the specimens 

 are so friable that they generally fall to pieces when they are 

 extracted from their matrix. Among these fossils we remarked 

 an abundance of some of the following genera : 



(1.) Faludina, 



(2.) Pot amides. 



(3.) Melaniay more than one species. 



(4.) Cj/clas, two species. 



(5.) Unio (?) generally in the form of large casts in whicbthe 

 nacre is beautifully preserved. 



(6.) Planorbis, more than one species. 



(7.) Lymiima, more than one species. 



The two last were not so abundant as the others. There were 

 also in the partings of some of the beds traces of vegetable 

 impressions. From the green marl beds of Thorness Bay, we 

 obtained very fine impressions of a kind of large flag. Adding 

 •what has been stated to the details already published by Mr. 

 Webster, we may conclude, that in every part of the north coast 

 of the Isle of Wight, from Alum Bay to Whitechff Bay, where 

 there is a good denudation, tlve lower freshwater formatioh may 



