AGES OP MATURE. 413 



DESCRIPTION OF FIG. 389. 



FOSSIL SHELLS AND TEETH OF MAMMALIA, PROM THE FRESH-WATER 

 EOCENE STRATA OF THE ISLE OF WIGHT. 



SHELLS. 

 Fig. 1 . Potomomya yregaria ; from Headon Hill. 



This shell is described by Mr. Sowerby in Mineral Conchology 

 as Mya gregaria. the genus Potomomya (river mussels) 

 comprises those species which inhabit rivers only, and are not 

 found in estuaries and brackish waters. 

 2. Pot amides concavus ; Headon Hill. 

 3. Melanopsis fusiformis ; Headon Hill. 



4. brevis ; Headon Hill. 



5. Neritina concava ; Colwell Bay. 

 6. Melanopsis carinata ; Colwell Bay. 

 7. Helix globosus ; Shalfleet. 

 8. Pot amides plicatus ; Headon Hill. 

 9. ventricosus ; Headon Hill. 



MAMMALIAN REMAINS 

 10. Upper canine tooth of Anoplotherium commune ; from Seafield 



near Ryde. 

 1 1. The grinding surface of anther molar, of Palaotherium medium; 



from Binstead. 

 12. One side of the lower jaw of Pakeotherium minus, with five 



teeth ; from Seafield.* 



13". A tooth of Dicholune ceromum, from Binstead. 

 13. The grinding surface of fig. 13". 



With the exception of the gigantic snail-shell, fig. 7, the fossil shells here 

 delineated are abundant at Headon Hill, and in the clays and marls at 

 Colwell Bay. The Mammalian remains are of excessive rarity, and have 

 hitherto only been found in the quarries near Ryde, and at Headon Hill. 

 From the latter locality, Dr. Wright recently obtained a fine specimen of 

 the jaw of a Dicodon, a new genus established "by Professor Owen. 



* See British FossU Mammals, p. 323. 



