OSBORNE BEDS. 157 



A fault at the Point, running in a direction 30° E, of S., skirts 

 the shore and brings up the Nettlestone division of the Osborne 

 Beds, in a manner that at first sight appears to be very puzzlino-. 



Nothing more is seen of the Osborne strata between Watch 

 House Point and WhiteclifF Bay. 



The strata composing the Osborne series were better displayed 

 at Whitecliff Bay in the summer of 1856 than at the time of 

 Professor Forbes's visit, when they were concealed by landslips, 

 or in grass-covered undercliffs. The following is a list of the beds' 

 then observed : — 



Section of the Osborne Beds in Whitecliff Bay. 



Feet. 

 Dark bituminous clay, with Limncea in patches - - 2 



Grit ........ I 



Dark olive-green clayey sand ..... 3 



Red and green mottled clays, with 1 to 2 inches of clay iron- 

 stone on the top of the bed - . . - - 18 or 20 

 Green clays - - . . . - -3 or 4 

 Dark grey sandy clays . . - . . 3 

 Shelly band, large Paludina, Melanopsis carinata • . 41. 

 Dark green marls ...... g 



Olive-green clay, Melanopsis carinata, Paludina lenta - - 15 to 18 



Fine cream-yellow limestone, running out to sea in a direction 



10° N. of E. No fossils observed - . . . j 



Green clays ; Paludina, Melanopsis .... About 15 



Total thickness of Osborne beds - . 791 



The foregoing sections will show how uncert lin and difficult to 

 fix is the boundary between the Headon and tlio Osborne Series. 

 When one examines the fossils also, not a single mollusc can be 

 found that is confined to the Osborne Beds, and the only peculiar 

 fossils are small and delicate fish and prawns, the preservation of 

 which is due to exceptional circumstances In fact, so little is yet 

 known of the fauna of the Osborne Series, that it still remains 

 doubtful whether these beds ought or ought not to be separated 

 from the Headbn. 



The paucity of species seems to be mainly due to the conditions 

 under which the beds were deposited. There is an absence of 

 truly marine beds, though a few marine shells occur. Purely 

 freshwater strata are also rare. The mass of the clays seems to 

 have been deposited in lagoons, varying in saltness, in which 

 could live brackish-water molluscs like Melania and Potamomya, 

 and a few of the more hardy freshwater and marine species. 

 Lagoons of this character are at the present day favourite places 

 for turtles and alligators, like those so abundant in this deposit. 



No doubt the Osborne Beds have been undeservedly neo-lected 

 owing to their proximity to the much more interesting Headon 

 and Bembridge Series. But the fish-bed, especially, is well worth 

 further examination and tracing into other parts of the Island. 



