1822.] Geology of the hie of Wight, S^c. 341 



of the beds. Nothing is placed before the eyes except an irre- 

 gular surface laid bare by a section transverse to the range of the 

 formations above the chalk. But we do know that a great argil- 

 laceous deposit, resting on the sand and plastic day formation, is 

 ahnost co-extensive with the basins of London and of the Isle of 

 Wight ; and that its general relations, and the fossils contained 

 in it, are identical with those of the stratum (B) in the section of 

 Alum Bay. On the other hand, we do not know, by the evidence 

 of other sections, that the stratum (d) is continuous. Indeed 

 there is all the proof which can be afforded by negative evidence 

 that it has no rank but that of an accidental or subordinate bed. 



It is further stated {Annals, p. 218) that the fossils of the 

 lower argillaceous bed (d) are identical with those of the jCo«- 

 don clay. This assertion, taken in its utmost extent, only proves 

 that the sea, during the age of the sand and plastic clay forma- 

 tion, was sufficiently tranquil to allow the propagation of certain 

 species of mollasca. Nor is it extraordinary that the progeny of 

 ■ these animals should be found in still greater abundance in newer 

 argillaceous beds, deposited under circumstances more favoura- 

 ble to the existence of organized beings. But after all, is the 

 assertion correctly true ? The argillaceous bed (J) was examined 

 by Mr. Henslow and myself during our first visit to the Isle of 

 Wight in the year 1819. 



The fossils of the stratum were principally confined to the 

 septaria. Among the specimens brought away on that occasion, 

 I find the following : 



(1.) Fragments of an oyster nearly resembhng ostrea pulchra^ 

 (Min.Con.pl. 279.) 



(2.) A }7iya and pinna, both probably London clay fossils; 

 because, if I mistake not, the same species are found in the 

 rocks of Bognor. 



(3.) Casts of two species of bivalves, and of one univalve. 



It is worthy of remark, that not one out of this suite is figured 

 in the Fossilia Hantoniensia of Brander. On the other hand, 

 thousands of fragments of the well-known London clay fossils 

 are dispersed through almost every part of the upper argillaceous 

 bed (B) ; agreeing (as was observed by Mr. Webster) in their 

 state of preservation as well as in their specific characters with 

 the organic remains of the Hampshire coast. 



Two other facts are brought forward {Annals, p. 218) to prove 

 that the beds we have been considering ought not to be separated 

 into iyfo formations, viz. the existence oi septaria in the stratum 

 (</), and the existence of decomposing rolled flints both above 

 and below the argillaceous bed (B). We may briefly observe ; 

 first, that septaria prove nothing respecting the age of the beds 

 in which they are contained ; because they are found in all the 

 argillaceous deposits associated with our secondary rocks ; and 

 secondly, that rolled flints prove nothing except the mechanical 

 origin of the banks of sand in which they are contained, and 

 may be found in any stratum which is newer than the chalky 



