100 



GEOLOGY OP THE ISLE OF WIGHT. 



Fig. 19. 

 Panopma intermedia, Sow. 



Fig. 20. 

 Ditrupa plana, Sow. 



^ (E^ 



with their valves joined, lying in the positions they occupied when 

 alive. Succeeding these, are similar beds with sandy alternations 

 and laminae, and a layer of large septaria. Pinna afflnis (Fig. 21) 

 is found in the septaria.* The total thickness of the London 

 Clay amounts to about 320 feet. A bed of flint-pebbles is found 

 at 255 feet above the base. 



Fig. 21. 



Pinna afflnis, Sow. 



No inland sections of the London Clay are now visible in the 

 Island, unless the cutting at Ashey is partly in this division. 

 Probably, however, the clays there exposed belong almost entirely 

 to the Bracklesham Beds, nearly the whole of the London Clay 

 being cut out by a strike fault. 



The fossils of the London Clay (see Appendix) have not yet 

 been fully collected in this district ; but as far as they go they 

 indicate a subtropical clhiiate, as in the Ijondnn Basin. The 

 occurrence of occasional scattered lines of flint-pebbles in the 

 clay is noteworthy. This and the more sandy nature of the strata 

 seem to point to a gradual shoaling of the sea towards the south, 

 at the time when the London Clay was in course of being 

 deposited. 



* See also Caleb Evans, On the Geology of the neighbourhood of Portsmouth and 

 Ryde. Proc. Geol, Assoc, vol. II. p. 70. (187L) 



