196 GASTEROPODA. 



Potamides submarginatus, Orbigny, 1850. 



Ceritliium marginatum. 

 Coq. Foss. Paris, 1833, vol. ii. pi. li. figs. 15, 16, p. 336, non Bruguiere. 



Cerithmm sitbmarginatum. 

 Prod. Pal^ont. 1850, vol. 2. p. 417. 



Horizons and Localities. 

 Upper Eocene. — Barton Beds. Bartou ; High Clifl'. 



Middle Eocene. — Brackksham Beds. Bracklesham Bay ; Brook ; Bram- 

 shaw. 



Potamides submarginatus^ var. recentior, Edwards (MS.). 



Horizon and Localities. 

 Oligocene. — Headon Beds. Hordwell ; Colwell Bay ; Mead End. 



Potamides tricarinatus, Lamarck, 1804. 



Cerithium tricarinatum. 

 Ann. Mus. 1804, vol. 3. p. 272. i 



Coq. Foss. Paris, 1833, vol. ii. pi. li. figs. 1-9, p. 325. 



Horizon and Locality. 

 Oligocene. — Headon Beds. Mead End. 



Potamides triserialis, Edwards (MS.). 



Horizon and Locality. 



Oligocene. — Hempstead Beds. Hempstead. 



Potamides vagus, Solander, 1766. 



Turho vagus. 

 Brander's ' Foss. Hant.' 1766, pi. iii. fig. 50, p. 26. (Specimeu in Braiider 

 Coll., but not the type.)  . 



Potamides? ductus. 

 Mineral Conchology, 1822, pi. 340. fig. 1, non Bruguiere. (Sowerby Coll.) 



Cerithium pseudo-dnctmn. 

 Prod. Pal^ont. 1850, vol. 2. p. 410. 

 Forbes's ' Isle of Wight,' Mem. Geol. Surv. 1856, pi. iv. fig. 7, p. 153. 



Cerithium trizonatum. 

 Forbes's ' Isle of Wight,' Mem. Geol. Surv. 1856, pi. iv. fig. 8, p. 153. 



Horizon and Localities. 

 Oligocene. — Headon Beds. Colwell Bay ; HordweU ; Freshwater ; Brocken- 

 hurst; Mead End; Headon Hill; WhitecliffBay; Lyndhurst ; Beaulieu 

 Road. 



Potamides varians, Edwards (MS.). 



Horizon and Localities. 



Oligocene.^Headon Beds. Colwell Bay ; Headon Hill. 



Potamides ventricosus, J. Sowerby, 1822. 



Bof.amides ventricosus. 



Mineral Conchology, 1822, pi. 341. fig. 1. (Sowerby Coll.) 



Cerithium ventricosum. 

 Forbes's ' Isle of Wight,' Mem. Geol. Surv. 1856, pi. iv. fig. 2, p. 152. 



Horizon and Localities. 

 Oligocene. — Headon Beds. Hordwell: Headon HiU; OolweU Bay. 



