TERRACES AND RIVER VALLEYS OF WESTERN EUROPE. 293 



REMARKS ON THE FOREGOING PAPER. 



Professor T. McK. Hughes, F.R.S., writes: — 



I wish I could be with you on Monday to take part in tlie 

 discussion upon my friend Professor Hull's paper. I am very glad 

 to see that he is carrying on his researches into the great move- 

 ments of the crust of the earth which, as I believe, are the chief 

 cause of climatal change, and the principal factors in all our 

 calculations as to the time required to build up the visible crust of 

 the earth, and also for all our speculations as to the succession of 

 events throughout geologic time in any area, I should like to ask 

 the author one question, and that is whether he thinks there is 

 sufficient evidence to refer tlie movements to any system in respect 

 of surface direction and whether there is any reason to believe that 

 the surface direction has been distinctly different or approximately 

 the sam.e in successive periods after a reversal of the vertical 

 direction of movement.* 



I am especially interested in the bearing of the results recorded 

 by Professor Hull upon the question of the causes of locally 

 recurring Ice ages, which I would refer almost entirely to geo- 

 graphical and not to astronomical causes. 



II Cavaliere W. P. Jervls, F.G.S., Keeper of the Royal Italian 

 Industrial Museum at Turin, writes: — 



This second paper by Professor Hull presents like interest to 

 his former one. Both alike open up the way to a vast field of 

 research in geology (and as the basis of great future discoveries 

 therein), physical geography, and in relation to the distribu- 

 tion of land and marine fauna of Upper Tertiary and recent 

 times. Such is the multitude of deductions to be drawn fi*om 

 the subject that there is no lack of matter for the cautions study 

 of many different minds. The real fear is that any should be 

 carried away to form rash generalizations, which are the sunken 

 rocks against which too many strike now-a-days, in their precipi- 

 tate dedu-Ctions in similar recondite subjects. 



Lest I myself should transgress this precaution I submit a few 

 somewhat bold considerations, in the hope that they may be 



* I fear that I do not see my way to answer Professor Hughes's 

 question without more consideration than I could give at this moment. — 

 E. H. 



Y 



