TRANSACTIONS OF SECTION C. 617 



The shells of Bridlington Shell Bed lived atout this time. 



13. The Cromer Till and Contorted Drift. First great ice-sheet. Lower 

 Boulder Clay of many places, Bridlington Shell Bed, and Shell Bed of Moel 

 Trjfaen, &c. Land higher than now. 



(e) Depression possibly only local in South-east England. 



14. The Middle Glacial Sand and (Jravel, result from melting ice. 



(/) Period of renewed great elevation possibly continuous ivith period (d) 



in the far north. 



15. The Great Chalky Boulder Clay. Ice-sheet extending over large area. 



_ N.B. — At some time during Periods {d), (e), (/), the land in North Europe was 

 raised to some 8,000 feet higher than now, and this is prohable date of completion 

 of excavation of Scottish lochs and Norwegian fjords. 



{(/) Period of depression. 



16. Corbicula fluminalis Beds of Grays and Crayford. Mammilliferous beds of 

 Sewerby and Hessle. Slight depression. 



Marine Gravel of Holderness 100 feet O.D., Brighton, Goodwood, &c.. Raised 

 Beaches. Further depression. 



(h) Period of elevation over lai-ge area. Last great ice-sheet. 



17. Plateau Gravel of Norfolk in part, and much of the Thames Terrace- 

 gravel, Purple and Hessle Clay of Yorks. 



Shell- banks of Rockall, &c., show elevation of Iceland, Scotland, Norwav, to 

 some 600 feet higher than now. 



18. Mundesley ' Eiver Bed' near close of this period. 



Probably the Raised Beach of Clacton, &c., belongs to a final period of depres- 

 sion (time of Yoldia Clay of Christiania), and in Norway there was a subsequent 

 elevation during which the terraces in the fjords were formed. 



9. Report on Life-zones in the Britinh Carboniferous Rocks. 

 See Reports, p. 210. 



