0)i British Drifts and the Interglacial Problem. 365 



drifts of other areas in England and Scotland, where beds 

 of supposed Interg-lacial ag'e have been described. His con- 

 cluding- summary is as follows] — 



Summary. 

 My subject has proved unwieldy ; and in merely sketching 

 its outlines I am uneasily aware that I have overstepped the 

 usual bounds of an Address. My conclusions — if the term be 

 applicable to results mainly negative — are as follows : — 



1. In the present state of opinion regarding the glacial 

 sequence and its interpretation in North Europe, it is premature 

 to attempt the arrangement of the British drifts on this basis. 



2. No proof of mild interglacial epochs, or even of one such 

 epoch, was discovered during the examination of certain typically 

 glaciated districts in England, Ireland, and the Isle of Man ; 

 and the drifts in these areas yielded evidence that from the 

 onset of the land ice to its final disappearance there was a 

 period of continuous glaciation, during which the former sea- 

 basins were never emptied of their ice-sheets. 



3. The ' middle glacial ' sands and gravels of our islands 

 afford no proof of mild interglacial conditions or of submergence. 

 In most cases, if not in all, they represent the fluvio-glacial 

 material derived from the ice-sheets. 



4. The British evidence for the Interglacial hypothesis, 

 though requiring further consideration in some districts, is 

 nowhere satisfactory. Most of the fossiliferous beds regarded 

 as interglacial contain a fauna and flora compatible with cold 

 conditions of climate ; and in the exceptional cases where a 

 warmer climate is indicated, the relation of the deposits to the 

 boulder-clays is open to question. 



5. The British Pliocene and Pleistocene deposits appear to 

 indicate a progressive change from temperate to sub-arctic 

 conditions, which culminated in the production of great ice- 

 sheets, and then slowly recovered. 



6. During the long period of glaciation the margins of the 

 ice-lobes underwent extensive oscillations, but there is evidence 

 that the different lobes reached their culmination at different 

 times, and not simultaneously. The alternate waxing and 

 waning of the individual ice-sheets may have been due to 

 meteorological causes of local, and not of general influence. 



Let me add, in closing, that it would have been a more 

 gratifying task if, instead of probing into these outstanding 

 uncertainties, I had chosen to deal only with the many and 



1906 October i. 



