132 GEOLOGY OF THE ISLE OF WIGHT. 



orbes, llmne'i) — and the almost momentary influx 

 of salt water during that period, which lasted only 

 long enough for a race of oysters to live and die 

 away — all render the tertiary strata in this locality 

 of high interest." * 



It may assist the collector to state that the 

 ditrupa bed is exposed in the cliff at the distance 

 of from 45 to 50 paces from the junction of 

 the lowermost tertiary clay with the chalk. At 

 150 paces further, towards Bemb ridge, are green- 

 ish grey sands and clays, in which the cardita 

 planicosta {PI. III. fig. 7), and numerous other 

 marine shells occur ; and about 200 paces onwards 

 similar shells, with large nummulites, volutes, 

 cerithia, &c, are abundant in strata of the same 

 character. -j- 



Sandown Bay. — To pursue the natural order 

 of our inquiry, we should now retrace our steps to 

 Ryde, and proceeding to the north-western ex- 

 tremity of the Island, examine the corresponding 

 phenomena in Alum Bay. But it may be more 

 convenient to the visitor if we first conduct him 

 to the southern side of Culver Cliff, where a 

 natural section of the strata of the cretaceous 



* l'aport of the fourteenth meeting of the Brit. Assoc, of Science for 

 1844. Transactions of the Sections, p. 41. 



t Sec an interesting paper " On the London and Plastic Clay Formations 

 nf the Isle of Wight," by .!. S. Bowerbank, Esq. F.R.S. Geol. Trans. 



