Headon Hill Sands. 



251 



such as Oaks, Yews, Cypress, Spindle-trees, Dryandra, 

 Laurels, Limes, Figs, Senifas, &c., &c., but all of 

 extinct species. In this assemblage of plants we have 

 ample evidence of the vicinity of land, and though 

 modern crocodilia have no special objection to salt- 

 water in the mouths of the Granges, yet they are not in 

 the habit of pursuing their game into the open ocean, 

 and we may therefore more than suspect, that even this 

 part of the Eocene series was deposited within the 

 ocean mouth of a great river such as the Amazons. 



The Bagshot series, including all the strata men- 

 tioned above, form the highest part of the Eocene 

 strata, which exclusively contain marine mollusca. 



We now come to the undoubtedly Upper Fresh- 

 water and Estuarine deposits. 



The Headon Hill Sands (fig. 47), including the 

 clays of Hor dwell Cliffs, come next in succession. These 

 form the lowest part of the great fluvio-marine deposits, 

 which constitute the remainder of the Eocene rocks of 

 Hampshire and the Isle of Wight, for none of these 

 strata are found within the area of the London basin. 

 Some of the marine shells of Hordwell are common to 

 the Barton beds. Its marine strata contain sharks' 

 teeth, Murex, Buccinum, Ancillaria, Valuta, Margin- 

 ella, &c., Oysters, Pectens, Corbula, Balanus, &c., 

 Fusus porrectus, Oliva Branderi, and Nummulites 

 Icevigata. The brackish-water strata have yielded Ceri- 

 thium mutabile, C. cinctum, Potamomya plana, &c., 

 and the fresh- water rocks contain Paludina lenta, Pla- 

 norbis euomphalus, Limncea caudata, Cyclas, several 

 species of Cyrena, Unio Solandri, Melania, &c., be- 

 sides land-shells of the genus Helix, and of vegetable 

 remains, two species of Carpolithes (a conifer), and 

 Char a Wrightii. In the Hordwell Cliffs and elsewhere, 



