572 Correspondence — Professor E. Hull. 



coI^I^:E]SI=OI^^^DEI^^c:E. 



SCANDINAVIAN ICE AND NORFOLK DRIFT. 



Sir, — In the article which appeared in the October number of the 

 Geological Magazine, I called the attention of Sir Henry Howorth 

 to the evidence for the former presence of an ice-sheet blocking the 

 North Sea during the period of maximum glaciation, based on the 

 deflection of the ice-strige along the eastern coast of Scotland. 

 Owing to that article having been written during my holiday in 

 Norfolk, and in the absence of the numbers of the Magazine previous 

 to that of August, I had overlooked the fact that Sir H. Howorth 

 had dealt with this problem in the April number of the Magazine, 

 and had deliberately rejected the hypothesis. I now ask for per- 

 mission to express my regret for this oversight. 



While on this subject, may I be allowed very briefly to state the 

 conclusions regarding the mode of formation of the Drift of North 

 Norfolk, at which T have arrived from an examination of the sections 

 along the coast and inwards about Cromer and Sherringham, I now 

 altogether abandon the view which I had held before this visit — 

 that the Drift deposits owe their origin to an ice-sheet stretching 

 from Scandinavia across the North Sea ; and to this extent I find 

 myself in agreement with Sir Henry Howorth and Mr. F. W. Harmer, 

 who reject the ice-sheet theory as applied to this part of England.^ 

 As regards the Boulder-clay laid open for miles along the coast, we 

 have a formation fairly uniform in character, distinctly laminated, 

 and not excessively laden with erratic stones and boulders. This is 

 not the kind of deposit we should expect from an ice-sheet, nor does 

 it bear a resemblance to the Till (or Lower Boulder-clay) of the 

 north-west of England and Scotland. It appears to me to be 

 a distinctly aqueous deposit, resembling (except in colour) the 

 Upper Boulder-clay of that region. What I believe I did see in 

 these cliif-sections was a deposit precipitated over the floor of the sea 

 in muddy waters, fed by glacier rivers, crowded with ice-floes and 

 bergs, from which the erratic blocks fell down and became imbedded 

 in the soft mud. Larger bergs of ice were also present, piloting 

 along those huge masses of chalk such as are seen on the coast- 

 section east of Cromer. Such conditions as the above would explain 

 the occurrence of blocks and stones derived from various sources. 

 The overlying " Interglacial sands and gravels" are also clearly 

 marine deposits, but laid down in shallower waters than those of the 

 Lower Boulder-clay, waters generally clear and free from muddy 

 sediment. The manner in which the gravels rest on an eroded 

 surface of the Boulder-clay shows that the sea-bed had become very 

 shallow, and that changes in the physical conditions of sea and land 

 had taken place ; the change in the character of the deposits being 



1 " On the Pliocene Deposits of Holland" : Q.J.G.S., November, 1896, p. 775. 

 Mr. Harmer says : " It is difficult to see how the Baltic Glacier could have reached 

 East Angiia, though ice-floes with Scandinavian boulders might easily have done so." 



