V 

 Correspondence — Mr. R M. Deeley. 335 



friend and myself might be perfectly satisfied of the identification of 

 this rock-type. The fact that such rocks occur as boulders in the 

 clay had long been a matter of common knowledge, and half an 

 hour's work at the cliffs will always px'oduce specimens of this 

 augite-syenite and of the equally characteristic rhomb-porphyry, the 

 two most striking rocks among the beach material. Surely it would 

 be " more in accordance with scientific laws of evidence " to ascertain 

 the facts of the case, either personally or from the records, before 

 propounding an artificial explanation of them. 



If further evidence be needed, I may add that I have recently 

 sliced and examined typical specimens of the two unique Scandi- 

 navian rocks mentioned above, which were collected at Cambridge 

 by Professor Hughes. 



St. John's College, Cambridge, Alfred Harker. 



June Ind, 1894. 



UNIFOEMITT IN GEOLOGY AND THE ORIGIN OF THE DRIFT. 



Sir, — Sir Henry H. Howorth opens a rather strangely reasoned 

 paper in your last month's issue with the statement that signs ai'e 

 accumulating everywhei'e that geologists are now harking back 

 to the views of the old catastrophists, and giving up the uniformi- 

 tarian views so ably placed on record by Lyell and later workers. 

 Where these signs are to be seen I am at a loss to discover. 

 Certainly not in the Nottingham Address of Mr. J. J. Harris Teall 

 to the geological section of the British Association, nor yet in the 

 text-books and original papers written during the last few years. 

 No doubt popular magazine writers will to some extent regard Sir 

 Henry H. Howorth's writings as being one of the signs of the 

 times, and will be ready to put his ideas before their readers as 

 "recent advances." Every supporter of uniformitarian principles 

 admits that floods and earthquakes have always occurred. Nor am 

 I aware that any exact limit has been fixed to their magnitude. At 

 least I never heard it argued that the eruption of Krakatoa, for 

 example, was the greatest outburst that has ever occurred, or that 

 there will never be a greater. It only asks us to seek to explain 

 the facts by slow and well-known causes that may be seen in every- 

 day action rather than by extreme or violent means. For instance, 

 the great majority of geologists consider that the distribution of the 

 drifts can be best accounted for on the assumption that large portions 

 of the northern continents were covered by immense ice-fields. 

 Judging from the present distribution of glaciers and ice-fields, etc., 

 Sir Henry H. Howorth thinks this view extreme and not sufficiently 

 uniformitarian, and pins his faith on floods and dancing mountain 

 ranges. The time has gone by for a general discussion on this point. 

 If a particular deposit can only be explained on the assumption that 

 there was a deluge, we must believe that there was a deluge. It 

 would be unscientific to settle upon the agent first and then point 

 to all sorts of deposits as being produced by it. 



But, to return to the paper, my intention was also to refer to 



