688 MR DAVID MILNE HOME ON THE BOULDER-CLAY OF EUROPE. 



These exceptions appear to indicate two agencies — one of a general, the 

 other of a local character. 



(1.) It has been already noticed, that in the Norfolk cliffs there is a boulder- 

 clay, the lowest of all the drift-beds, which lies directly on the chalk rocks. In 

 this boulder-clay there are boulders which have been identified by Sir Charles 

 Lyell, Dr Mitchell,* and other geologists, with the rocks of Sweden and Norway. 

 Mr Geikie mentions (" Geology of Scotland," p. 303) that Professor Ramsay and 

 he found Scandinavian rocks at the mouth of the Tees. No one doubts that these 

 boulders must have been transported on floating ice, and by a current from the 

 N.E. or N.N.E. Agassiz f himself allows the correctness of this view, observing 

 that the " Swedish blocks on the coast of England may have been transported on 

 floating ice." And again — " The Norwegian blocks found on the coast of England 

 have been correctly assigned by Lyell to a similar origin, viz., to masses of ice 

 set afloat." 



It is not merely on the Norfolk coast that these traces of a north or north- 

 easterly current, with floating ice, exist. Mr Tate of Alnwick informs me in a 

 letter (1st January 1869) that, at Alnmouth, " he took the direction of the striae 

 on two blocks as they lay in the clay, each block being about 3 feet long. In 

 one, the striaB were from N. to S., in the other, from N.N.E. to S.S.W. (true 

 bearings)." In his " History of Alnwick," published since the date of his letter, 

 Mr Tate states, that at Abberwick, four miles west of Alnwick, there is a block 

 of grey granite like that at Aberdeen, which he refers to in proof of his remark 

 that there are in the district boulders which have been transported great 

 distances. The same accurate observer, in a note on the Fame Islands, in the 

 sixth volume of the " Transactions of the Berwickshire Naturalists' Club," 

 mentions, " that the surface of the whole of these islands had been ground and 

 smoothed by the passage of a powerful agent. Besides the smoothed surface, and 

 rounded little rock knolls, there are ruts or narrow hollows of some length, 

 whose sides and bottom are smoothed and striated. From the slope of the 

 dressings, it appeared that the agent had moved from the northward, which is 

 not from the land, but from the sea, and nearly parallel with the coast. On these 

 islands a larger area of glaciated surface is exposed than in any other part of the 

 north of England." 



The late Dr Fleming, in his "Lithology of Edinburgh," p. 77, notices the 

 occurrence of flints in the drift beds of Fifeshire and Aberdeenshire, which he 

 infers, and with much probability, came from the chalk rocks of Denmark. 



It is also a fact of no small significance, that in the Shetland Isles J the stria- 



* Proceed. Lond. Geolog. Society for Nov. 1838. 



f Proceed. Lond. Geolog. Society for Nov. 1838, pp. 179, 331. 



J Hibbert, Edin. Journ. of Science for 1831, vol. iv. 



