500 S. V. WOOD, JUN., OK THE KEWER 



Stage ly . The Gravel resulting from the Ice melting in part of the 

 area which had risen above the sea-level. 



The events of whicli I propose to trace the evidence during this 

 stage, though gradual and far from cataclysmic, occupied but a short 

 time, geologically speaking. In Stage Y. the fall of the line of marine 

 gravel (e) over the Chalky Clay is traced from upwards of 500 feet in 

 Sheet 62 to its disappearance at Ordnance datum in Sheet 50, as 

 well as the amount of rise in the land which took place during the 

 formation of that clay, from both of which it results that the whole 

 of Norfolk and North Suffolk, with the exception of the parts at 

 lowest elevation in the west of these counties, had at the close of 

 that formation risen above the sea-level, and that the ice which 

 passed through the Norfolk valleys to the North Sea reached it 

 beyond the present coast of Norfolk. 



There is, however, in Central Norfolk a large formation of gravel 

 occupying elevated areas over the Chalky Clay, and distributed in 

 alternate patches with it, which is, with slight exceptions, such as 

 that mentioned (in Stage III.) at Stewkley, peculiar to that county — 

 this clay, except such as falls below the line of the gravel e, being 

 everywhere else bare and bald. 



The greatest mass of the ice lay within the broken line of Map No. 1, 

 up to which, as I have already described, it destroyed and recon- 

 structed all the earlier part of the moraine laid down over gravel ; 

 and we may therefore infer that when it had to a great extent shrunk 

 into the Norfolk and Suffolk valleys, an immense mass of it lay 

 high on Western Norfolk, and overlooked the "Wensum valley from 

 the west. 



In Greenland the melting of the snow on the surface of the land- 

 ice during summer causes torrents of water to pour through fissures 

 in this ice, which eventually issue beneath its termination into the 

 sea ; but this water, from the surface-thawing of the ice in West 

 Norfolk, would pour from it into the Wensum valley, filling that 

 valley above the ice which occupied it, and flooding the surface of 

 the moraine which the shrinkage had laid bare. 



It is to the currents of water thus poured from this mass of ice, 

 after the shrinkage began, that I attribute those extensive beds of 

 gravel which have been described by Mr. Harmer and myself under 

 the name of " Cannon-shot," the principal extension of which is 

 in the west of Sheet QQ. Here, for the most part, they consist of 

 thick beds of flints rolled into the shape and dimensions of the now 

 obsolete cannon-shot of from 12 to 32 lbs. calibre, and even larger ; 

 and we attributed their origin to some local modification of the 

 Chalky Clay formation by powerful currents, for we sometimes found 

 imbedded in the gravels heaps of sand formed almost wholly of 

 chalk-grains. 



Another feature of these gravels is, that above the confluence of 

 the Wensum with the Yare, near the centre of Sheet QQ, they are 

 confined to the western slope of its vaUey, and to the plateau on 



