234 



ISLE OF WIGHT. 



signs of partial disturbance in these beds ; the whole appears there- 

 fore to have been moved together." 



Close adjoining the veriical strata on the northern side of the is- 

 land, occurs a series of horizontal strata, which are distinctly visible 

 in a hill called Headon : — these strata consist of an alternating series 

 of fresh water and marine deposits, bearing a striking similarity in 

 their fossil contents, to the strata in the vicinity of Paris. Accord- 

 ing to Mr. Webster, they consist of 



1. A calcareous stratum, containing only fresh water shells. — TJp- 



7) er fresh water. 



2. Greenish marl with marine shells. — Upper marine, 



3. Marl with fresh water shells. — Loiver fresh water. 



4. Dark blue clay without shells. — Lower mai'ine. 



Thus, we have over chalk four distinct formations. No. 4. A 

 lower marine formation, which includes the London clay. A lower 

 fresh water formation, No. 3. The strata of this formation consist 

 of sandy, calcareous and argillaceous marl ; some of them appear 

 to be formed, almost wholly, of the fragments of fresh water shells, 

 without any mixture whatever of marine shells. " From the quan- 

 tity of these shells, and the regularity and extent of the strata 

 we are compelled" says Mr. Webster, " to admit, that the spot where 

 they now are, was once occupied by fresh Vi^ater, in which these an- 

 imals existed in a living state. Over this fresh water occurs an up- 

 per stratum, No. 2, which contains a vast number of fossil shells 

 wholly marine. Again, over this marine formation, in the same hill, 

 is a calcareous stratum, fifty five feet in thickness, No. 1, every part 

 of which contains fresh water shells in great abundance, without any 

 admixture of marine exuviae. Many of the shells are in high pre- 

 servation ; and the animals must formerly have lived in the very spots 

 where they now are, the shells being so fragile, that they could not 

 have been removed from their original situation without breaking. 

 Part of the stone of this formation is very hard and compact, and 

 has long been used extensively for building stone. This stratum ap- 

 pears to have extended over the whole of the northern part of the 

 Isle of Wight ; but it has not yet been discovered in any other situa- 

 tion on this side of the water: it may be considered as the latest for- 

 mation of rock with which we are acquainted in England, and it 

 agrees in many of its mineralogical characters, and the fossils it con- 

 tains, with the fresh water limestone calcaire cfeaux douce, in the vicin- 

 ity of Paris, they are different from any other known rock." But no- 

 where has there been discovered, in the series of freshwater strata 

 in England, any trace of the remarkable beds of gypsum containing 

 bones of unknown genera, and species of quadrupeds, similar to the 

 gypsum of Montmartre. 



During a recent visit of the author to the Isle of Wight, he was 

 induced to conclude, that some of the remarkable phenomena which 

 this island presents, would admit of a more simple explanation than 



