Searles 7. Wood, Jun, — The Climate Controversy. 395 



land ; and though we may infer that the excavation of valleys 

 is more probably due to terrestrial agencies than to marine, it is not 

 impossible that powerful currents, issuing from beneath the termina- 

 tion of the land-ice, may have been the agent of the excavation in 

 question. Connected with the same subject is the age of the Pake- 

 field mammaliferous deposit and forest-growth, for this deposit and 

 growth is, while demonstrably newer than the Crag (which that on 

 the Cromer coast is not), so dissociated from the Lower Glacial 

 formation, though overlain by the Middle, tliat it is quite possible it 

 may be of interglacial age ; and if it could be proved so, would go 

 far to establish that the interglacial valley excavation of East Anglia 

 was due to terrestrial agencies, as well as that this terrestrial condi- 

 tion was accompanied by a climate which supported a growth of the 

 forest-trees whose trunks I have seen at Pakefield. This, however, 

 is only a possibility ; and as such is the only break, either in climate 

 or continuity of marine conditions, that I can discern in the Glacial 

 sequence in England. It also appears to me that Scotland, with the 

 northern parts of England, formed together an ice-centre (or possibly 

 several ice-centres) quite independent of, and detached from, the 

 Scandinavian and all other ice, unless it were, perhaps, that of Wales 

 and Ireland ; and that gradually, as the northern and mountainous 

 parts of the island became enveloped by land-ice, the whole of 

 Britain underwent depression, this depression extending in the 

 northern part and in Wales to 1500 feet, or more, below the present 

 level, but diminishing southwards and eastwards, so that most of 

 France continued above the sea. The southern portion of England, 

 with the exception, perhaps, of a few of the most elevated hills which 

 had then come into existence, was thus covered by the sea ; but this 

 was barred out of the northern portion and out of Scotland by the 

 enveloping land-ice, the material produced by the degradation of the 

 formations on which this rested travelling out beneath it to the sea, 

 carried at the bottom of the bergs as they broke off, and dropped (some- 

 times in large masses) over the contiguous sea-bottom. Thus, omitting 

 from consideration the lower division of it, in consequence of the 

 uncertainty attending the break before referred to, the rest of the 

 Glacial formation of England indicates to my mind the gradual 

 recession of this land-ice towards its centres, the formation follow- 

 ing that recession, and having its sequence partly in the vertical, but 

 much more in the horizontal direction, by reason of its having ac- 

 cumulated principally in contiguity to the land-ice, and having, in 

 following up its recession, occupied the place left vacant by it. By 

 this process the mountainous parts of our island eventually assumed 

 the condition of a snow-capped archipelago, when the gravels and 

 sands of Moel Tryfaen, Macclesfield, and other elevated districts, were 

 deposited, and finally the ice and snow disappeared and emergence 

 took place. It was not, as it seems to me, until after this emergence, 

 which we are accustomed in England to regard as marking the com- 

 mencement of the Post-Glacial period, or during its progress, that 

 Britain became again inhabited by the great mammalia. Looking at 

 the presence of such fluviatile moUusca as Cyrena fluminalis and 



