526 S. V. WOOD, JUN., ON THE NEWER 



by the continuous rampart of the Pennine, no such accumulation of 

 ice took place there as that which, meeting with resistance in its 

 escape down the valley of the Eden and the Lune, mounted the 

 Pennine watershed at Stainmoor. Hence the ice which resulted from 

 the snows which Snowdon intercepted, passing more freely down it 

 and through the valleys which furrow its sides, avoided some of those 

 shoulders of the mountain mass on which these gravels had accu- 

 mulated, such as Moel Tryfaen, and there, and there only, are they 



Throughout the long period which is embraced in this part of my 

 memoir, nothing presents itself which to my apprehension indicates 

 any oscillation of climate whatever. The increase of cold from the 

 commencement of the Red Crag to the advance of the ice into the 

 sea of that Crag extended as I have shown it at the outset of Stage 

 II., and before the change in inclinatioQ and consequent submerg- 

 ence of all England took place, appears to have been uninterrupted, 

 while its recession from that position was merely the consequence 

 of that change of inclination and great submergence. As to the 

 epoch when the maximum of cold was attained, this, for aught I 

 ean see to the contrary, may have been attained during the forma- 

 tion of the Cromer TiU and remained unaltered up to the close of the 

 Chalky Clay, decreasing thence to the close of the Glacial period ; 

 and we must not confound the maximum of glaciation with the 

 maximum of cold. The shrinkage of the ice of the Chalky Clay 

 does at first sight seem to indicate the intercalation of a warmer 

 climate ; but on examination such an explanation seems unneces- 

 sary. It occurred to me that this shrinkage might have been due 

 to the transit of the ice over the Pennine watershed at Stainmoor, 

 which so far interfered with the ice of the Chalky Clay as to cause 

 this to diminish, and thus give rise to the phenomena which I have 

 described in that respect ; but on reflection I do not see that this 

 could have been the case ; and the shrinkage must, I think, have 

 been due to a different cause. As the shrinkage began in East 

 Anglia when some 80 feet of the total rise which took place during 

 the accumulation of the Chalky Clay remained to be accomplished, it 

 was probably due to the effect which emergence produced on this 

 shallowest part of the submerged area, by pushing the North Sea so 

 much further off; for where the sea was deeper, and so remained in 

 greater contiguity to the Pennine throughout the Chalky Clay, as was 

 the case in Sheets 53, 62, and 63, the shrinkage appears, from the 

 coincidence in level between the gravels c and e, not to have occurred 

 until the close of the formation. The eventual retreat of the ice of the 

 Chalky Clay can therefore, I think, have been due only to a dimi- 

 nution in the supply from amelioration of climate; for which 

 reason the western arm of the ice of the Purple Clay (which was a 

 remnant of the ice of the Chalky Clay, reinforced by a branch from 

 that which, crossing Stainmoor and issuing through the Tees valley, 

 had given rise to the coast-belt of Purple Clay) reached no further 

 than the north of Sheet 82. 



Whether vegetation adequate to the support of great Mammalia, 

 whose remains occur in the Hoxne brickearth and other deposits 



