212 NEOZOIC TIME. [CHAP. XI. 



quantity necessarily implies that there was a large and 

 varied flora in the jungles surrounding the lacustrine area. 

 Eventually, however, a submergence took place which 

 brought in the brackish waters of the adjacent estuary and 

 converted the greater part of the area into an oyster-bed, 

 for in Whitecliff Bay such a bed overlies the limestone. 

 The higher Bembridge beds are marls containing Cyrence, 

 Melanice, and other shells which lived in fresh and brackish 

 water ; and these marls are thicker in the eastern part of 

 the island. 



The base of the Hempstead group is taken at a band of 

 black carbonaceous clay, which contains freshwater fossils 

 and plant remains and seems' to be the relic of an actual 

 terrestrial surface. At Hempstead it is succeeded by about 

 140 feet of variously coloured clays and shales, with fresh- 

 water and estuarine fossils, passing up into green and 

 brown clays with some purely marine fossils. 



Mr. Clement Reid has recently discovered that the 

 Hempstead Beds have a much wider extension in the cen- 

 tral and eastern parts of the island than was previously 

 supposed, and moreover that they are thicker to the east of 

 the Medina river than they are at Hempstead. Thus the 

 lower beds, which at Hempstead are only 140 feet thick, 

 are at Wooton 180, and include a group of soft sands 

 about 50 feet thick. 1 



Passing over to France, a somewhat similar series is 

 found in the Paris basin. A lower group answering to our 

 Headon Beds commences with a freshwater limestone (Cal- 

 caire de St. Ouen), above which are marine sands and 

 marls succeeded by gypsum with freshwater marls. The 

 next group consists of greenish marls with marine fossils 

 succeeded by thick sands and sandstones (Gres de Fon- 

 tainebleau), and these correspond to our Bembridge and 

 Hempstead Beds. The highest member is a freshwater 

 1 " Geol. Mag.," 1887, p. 510. 



