PLIOCENE PEEIOD IN ENGLAND. 493 



On the vegetation of this uncovered fringe the Greenland rein- 

 deer feed. 



Compared with the condition of England at the period of greatest 

 submergence, this map would present great differences, for in 

 a representation of the state of things at that time every island thus 

 shown in Sheets 1, 2, 48, 49, 50, 66, 67, and 68 would disappear, 

 as well as some of the smaller islands in the other Sheets, while all 

 the rest would be reduced in size. 



A comparison of this map with that numbered 1 will show to 

 what extent these islands were overwhelmed by this clay ; but it is 

 singular that the western part of that one of these islands through 

 which the division-line of Sheets 51 and 52 runs, and which part 

 is formed of the yielding Neocomian sands of Potton and Sandy, 

 rising to no great height, should, though enveloped on all sides by 

 the ice, not have been overwhelmed by it, the clay (and possibly, 

 therefore, the ice also) not having covered it. This is the case also, 

 though to a less extent, with the island formed of the same sands 

 around "Woburn, in Sheet 46. 



The labour which my friend Mr. Harmer gave to the work of 

 mapping Sheets 66, 67, 68, and 69, and the care, skill, and minuteness 

 with which he accomplished this task, enable me to trace exactly 

 the course which the ice took after overwhelming the west of island 

 No. 1 and the islands to the south of it. 



The long narrow peninsula which juts out south-eastwards is, 

 like all that part of this island which occupies Sheet 68, formed of 

 the beds of Stage II., capped by so much of c as had emerged pre- 

 viously to the particular time of this description. Omitting d and 

 e, the beds forming the northern end of this peninsula were at this 

 time as shown in fig. YIII. At the southern end they were as 

 shown in fig. IX., and without much or any capping just there of 

 previously- emerged c. This peninsula was flanked on its southern 

 side by the narrow island of similar formation to which I have 

 already adverted as forming the south side of the Wensum valley, 

 near Norwich, and which also divides the valley of the Wensum from 

 that of the Yare. This island has probably a greater extension 

 north-westwards than is shown, or was one of a chain extending in 

 that direction now concealed by the almost continuous pall of the 

 Chalky Clay there. 



Entering upon the Wensum fjord thus formed, the ice laid the 

 Chalky Clay over c ; for Mr. Harmer and I found it in that position 

 low down in this vaUey in a temporary excavation in Fakenham 

 town, though in that part of the valley, and for some distance also 

 south of the part which is crossed by the line of fig. YIII., the 

 junction has been generally destroyed by the subsequent cutting- 

 out action of the ice. That part of island No. 1 which lies in 

 Sheet 66 was not (owing to reasons given in Stage Y.) overwhelmed 

 by the ice, which only rose against its southern flank, where it laid its 

 moraine (d) in the way shown by fig. YIII. Passing thus south- 

 eastwards, it laid its moraine over c, which had been and still was 

 accumulating in the fjord represented by this valley, then partially 



