Cardita simplex. 

 Cytherea incrassata. 

 Corbula cuspidata. 



pisum. 



Cyrena deperdita. 



obovata. 



Ostrea ventilabriim. 



HEADON BEDS. 141 



Buccinum labiatum. 

 Bulla, sp. 



Cancellaria elongata. 

 Cerithium elegans. 

 Natica labellata. 

 Pleurotoma plebia. 

 Rostellaria, sp. 

 Voluta geminata. 



The occurrence of Cardita simplex and Voluta geminata is inter- 

 esting, for these are Brockenhurst species previously rare or un- 

 recorded from the Isle of Wight. Both are abundant in this well. 



Between 420 and 434 feet grey shelly sand with Natica, 

 Pleurotoma, Nematura, Potamomya, Cyrena, and Planorhis occurs, 

 so the Middle Headon Beds seem to be at least 113 feet thick. 

 This thickness is much greater than at the west end of the island 

 but agrees very well with the WhiteclifF Bay section. The increase 

 of thickness of the marine beds is apparently due to the incoming 

 of the Brockenhurst beds, which are absent towards the west. 

 Below the sand the boring penetrated 3 feet into clay, in which 

 no fossils were observed. This clay ought perhaps to be referred 

 to the Lower Headon Series, for the occurrence of Potamomya 

 and Planorhis in the bed above seems to indicate a change of 

 conditions at this point, but unfortunately the boring v/as carried 

 no deeper. 



Another well, at Woodvale {see Appendix, p. 315), a short 

 distance from the last section, penetrates about 13 feet into the 

 Middle Headon Beds, with Potamomya. gregaria, Cyrena. obovata, 

 Ostrea, Melania, muricata, Cerithium conca.vum, C. trizonatum ? 

 The beds seem to correspond with those seen on the foreshore at 

 Osborne. 



The Headon Beds reap;)ear for a short distance at the extreme 

 northern point of the Isitmd, brought up by a local undulation 

 connected with the rise of the beds on the north side of the Isle of 

 Wight syncline. During the progress of the first Survey of the 

 Island these beds were well seen at the foot of the cliff near 

 Osborne and Norris Castle. But now the building of the sea 

 walls and the erection of groynes has almost entirely hidden the 

 sections, though abundance of Cerithium conca.vum can still be 

 found on the beach. The following description of the beds is 

 entirely taken from the first edition of this Memoir : — 



Due north of East Cowes, a little round the first Point, light- 

 green and red sandy clays, with bands of compressed Melania 

 costata and bivalves, forming a shell-marl, have slipped from a 

 higher level on to the shore, and Paludina lenta, Cyrena ohovata, 

 Potamides {Ccrithiimi) concavum, often in a silicified condition, 

 lie scattered in great profusion on the beach. 



Immediately under these, apparently, and seen also on the 

 shore, are 1 to 2 feet of greenish-grey clays, with occasional sandy 

 laminse, and numerous bands of Potamomya sparingly mingled with 

 Paludina. lenta, Cyrena. ohovata, and an occasional C. jnilchra. 



Bands of crushed Paludina lenta occur lower down, succeeded 

 by bands of Melanoysis, with remains of Fish (scales, vertebra3, 



