TRANSACTIONS OF THE SECTIONS. 53 
district in the area of their life-period is undoubted ; but as to how many of these 
coexisted, or to what extent they indicate a successive occupation, is still an un- 
decided question. A 
The “ Forest-bed” of Cromer gives a glimpse of what was the vegetation of this 
period; but here, again, it is more than probable that it must be taken only as the 
facies of the flora of the last stage of terrestrial conditions antecedent to the next 
great physical change, rather than that of the whole period. 
The whole mammalian fauna, from the Norfolk Mastodon to the Mammoth 
(Elephas primigenius), seems to offer itself as an assemblage of the members of 
nomad tribes, which have yet to be reduced to order of time. The general condi- 
tion 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 tempe- 
rate and to arctic. To its close belongs the evidence everywhere recurring, and at 
every level, of its subaérial glaciation and greater elevation. 
Just as the Crag and Falun beds come in here, on our East-Anglian district 
and on the Continent, as breaks in the lapse of tertiary terrestrial conditions, so 
the accumulations of the great northern submergence come in as a second intercala- 
tion ; only that the physical change in this case was greater and of a different order. 
To what this ultimately amounted, is represented on the map of the northern hemi- 
sphere*. The arctic basin extended itself as low as to N. lat. 50° by a slow process 
of submergence from north to south. 
Again the northern hemisphere emerged, apparently, in a contrary direction, or 
from south northwards; again the agencies of ice and snow and excessive rainfall 
are exhibited, till again, for its general arrangement of land and sea, this immediate 
district and England generally is presented with the like relations as it had at the 
period of the Crag-sea. 
The general character and the order of change of the Kainozoic period admit of 
being thus briefly told; but when it is attempted to follow out this change in its 
details, it is found to be a long and complicated record. 
Over the whole of the European area, as yet less accurately traced across the Asi- 
atic, very distinct upon the American continent, there is a region which presents 
broad expanses of waterworn detritus, sands, and loams, often placed at consi- 
derable elevations above present water-levels, which, from their superficial ex- 
tent, has caused them to be identified with the component members of another 
detrital group (the glacial drift) peculiar to another area, from which they are 
distinct as to conditions and mode of accumulation. The conditions indicated 
are those of low winter temperatures, terrestrial surfaces with a configuration such 
as the same countries have at present, alluvial and fluviatile accumulations, indi- 
cative of torrential and periodic rivers. 
A line drawn across the European area, occasionally on one side or other of that 
of north lat. 51°, defines the north limit of all this class of detrital accumulations 
of the Kainozoic period; on the south of this all these accumulations have their 
limits, and the sources of their materials are within the areas to which belong the 
existing river-systems of the South and Mid-European continent. 
North of this line the detrital accumulations are neither local as to composition, 
nor have they much reference to surface configuration, although such configuration 
preexisted. Over this area, too, are the indications of low temperatures and broad 
alluyia. The distribution of the detritus over this area shows that the expanse 
water was continuous, and was marine. Over one area are the results of a 
"en and uniform submergence ; over the other the phenomena are local and 
uvial, 
Over the British and part of the European area there is a good break in Kaino- 
zoic time into preelacial and postelacial,—by the term “glacial” being signified 
the period of the great extension of the Arctic basin, 
This Drift-formation, in one form or another, covers the whole surface of this 
county, 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. There 
are other parts of this island where the submergence exceeded this, even in this 
latitude ; so that here the highest land may not be a measure of the greatest 
* A map of the northern hemisphere was exhibited to the Section, 
