246 ANNUAL OF SCIENTIFIC DISCOVERY. 



pean area there is a good break in Kainozoic time into pre-glacial 

 and post-glacial. This drift-formation, in one form or anotiier, 

 covers the whole surface of this coiint}^ from the sea-level up to 

 the summits of the chalk hills. We have in Norfolk evidence of 

 submergence to the extent of 600 feet and upwards. It was a time 

 when the whole of the British Islands group became submerged, 

 with the exception of a few salient points ; and, taking the levels 

 to be derived from these points, together with the general charac- 

 ter of the phenomena, we may accept as certain that subaerial gla- 

 ciation, in all its varied modes of action, had long been at work 

 here prior to that submergence. The change of relative level was 

 not sudden ; iU proceeded from north southward ; and it is in the 

 north that the amount of the submergence was the greatest. 



On evidence such as this, the North Sea area, after the period 

 of the early Kainozoic fauna, or true crag, was seen to be passing 

 again to the condition of terrestrial surface. This old depression 

 of the North Sea, like other tertiary basins, again became part of 

 the general European land surface. A long list of animals, some 

 of which ranged over Central and Southern Europe, no doubt in- 

 cluding this very district, had left their remains there. 



The whole mammalian fauna, from the Norfolk mastodon to the 

 mammoth, seemed to offer itself as an assemblage of the mem- 

 bers of nomad tribes which have yet to be reduced to order of 

 time. The general condition of Northern Europe was terrestrial 

 for the whole of the tertiary or Kainozoic period ; during that time 

 its conditions as to climate passed from warm to temperate and to 

 arctic. To its close belonged the evidence everywhere recurring, 

 and at everj^ level of its subaerial glaciation and greater elevation. 



He said the subdivision of the East Anglian Kainozoic was as 

 follows : pre-glacial, glacial, and post-glacial. 



Pre-glacial. — Crag, in Suffolk, is a local agricultural name for 

 any sandy, gravelly soil ; but the early geologists and shell-col- 

 lectors soon found that it was something more ; its very perfect 

 shells were recognized as in part agreeing with those of the neigh- 

 boring seas, in part as unknown or foreign. It was not till 1835 

 that a subdivision of the crag was proposed by Mr. Charlesworth ; 

 and it was amended (in 1838) by the following classification : Up- 

 per Crag of Norfolk and Suffolk, — a. Without mammalian re- 

 mains; h. Beds with mammalian remains. Red Crag, 150-200 

 species of marine shells. Coralline Crag, 300-400 species of ma- 

 rine shells. Thus far back Mr. Charlesworth separated the Nor- 

 wich Crag from that of Suffolk. 



The Forest-bed of Cromer (1824) is one of the most interesting 

 points in Norfolk geology ; it is the unmistakable indication of a 

 terrestrial surface, antecedent to the period of the "glacial-drift" 

 accumulations. This old land-surface, at Cromer, is exposed at 

 the sea-level ; but it extends inland, and has been met with at con- 

 siderable depths in the offing. The arboreal vegetation buried in 

 these beds comprises the Norway si^ruce, Scotch fir, yew, oak, 

 alder, — all of them common north European trees. What the 

 Cromer coast-section demonstrates is, that by process of change 

 of level a forestial condition of the surface had been brought down 



