Ixii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [vol. lxxvi, 



England before Glaciation. 



The delimitation of ' the Glacial Period ' as a definite time- 

 interval has always presented difficulties. Usually the term is 

 intended to cover the whole of the cold period or periods of 

 Pleistocene times ; but in England it is more commonly used in a 

 restricted local sense, for the time during which deposits owing 

 "their origin to the presence of ice were accumulated in any 

 particular district, even though it be recognized that the event was 

 not synchronous, or of equal duration, over the whole country. 

 This ' English Glaciation Stage,' as it might be more correctly 

 called, evidently occupied only a portion of the ' Glacial Period ' in 

 the broader sense, and I am inclined to think that it found place 

 rather late in the period. At any rate, the longer I have studied 

 the English drifts, the more strongly have I been impressed with 

 the importance and complexit} r of the chain of events between the 

 onset of the cold conditions and the actual glaciation. In Norfolk 

 this interval is partly represented by the variable series of marine, 

 estuarine, and freshwater deposits below the Cromer Till, and, more 

 imperfectly, in East Yorkshire and a few other parts of the country 

 by patches of Raised Beach and of Land Wash ; but for the 

 country generally it was a time of severe erosion, yielding little or no 

 stratigraphical evidence, and marked only by the physiographical 

 changes wrought upon the land. 



During this time there was a general uplift, or emergence, by 

 which the marginal platforms carved out around many parts of our 

 islands during late-Tertiary times were elevated into plateaux of 

 moderate height and were sharply dissected, while the hill-ranges 

 beyond them were deeply incised with drainage-systems which 

 have lasted, with minor modifications, to the present day. It is 

 hard to say how much of the time should be reckoned as falling 

 within the Glacial Period proper, but we have evidence that the 

 prevalent characteristics of its climate were heavy precipitation, 

 powerful seasonal floods, and a low winter temperature. Round 

 the outskirts of the land, the principal valleys were graded down 

 to considerably below present sea-level, and most of their detritus 

 appears to have been swept far beyond our existing coast-line. 

 Since the land-margin at this stage lay everywhere much to the 

 seaward of its present place, it is quite inaccessible to observation, 

 so that we cannot determine its extreme position or trace its 

 changes. It was probably not long stable in any place ; as we 



