XC PROCEEDIIireS OF THE GEOLOGICAL SOCIETY. 



whole vale of Switzerland, to scoop out these rocky basins of 

 Greneva or Neuchatel. I will not waste your time by stopping 

 to discuss tbe question whether the mere vertical pressure of the 

 ice, without any forward motion, could have produced this effect ; 

 for, to refer to nothing else, how could the material thus abraded 

 be removed ? 



Although I fear I have too far trespassed on your time already, 

 and am most unwilling to prolong this discussion at present, yet 

 one other argument occurs to me, which I think deserves some con- 

 sideration, although I am not prepared to say what weight physicists 

 may attach to it. Allow me, therefore, to enunciate it for your 

 consideration. Let us, for the sake of argument, admit that this 

 gigantic glacier-field, covering nearly 3000 square miles, and im- 

 pelled by some mysterious power, this vis a tergo of which we have 

 heard so nmch, did really move with slow but irresistible motion 

 over the sites of these Alpine and Swiss lakes, pressing upon the 

 rock below with the whole force of the superincumbent weight 

 of a mass of ice 3000 feet in thickness ; let me then ask whether 

 the friction caused by the motion, however slow, of such a tre- 

 mendous weight would not develope such an amount of heat 

 as to reduce the ice in contact with the hard rocks into a liquid 

 state? Wotdd not the ice be melted, and a stratum of water 

 be thus introduced between the ice and the rocky surface ? and 

 would not this stratum of w^ater thus interveniug act as a kind 

 of cushion to prevent the ice from exerting any abrading power 

 on the rocks beneath ? I cannot resist the conviction that some 

 eifect of this kind would necessarily be the result of the conditions 

 I have mentioned, but I merely venture to throw out the idea for 

 further consideration, without wishing to press it unduly. 



But before leaving this subject, which still requires much local 

 examination, it will perhaps be expected that I should offer some 

 suggestions as to the probable causes of these lake-basins. I 

 might decline the inquiry, as I have never made this question a 

 subject of special investigation on the spot. I therefore shall not 

 allude to the general question. But, with reference to the two 

 lakes of Greneva and Neuchatel, some facts occur to me which I 

 think may throw light on their origin. It is well known, from the 

 researches of Swiss and other geologists, that during the Eocene 

 period and some portion of the Miocene, the greater part of the 

 Alpine and the Jura Mountains were submerged. When at a 

 subsequent period these mountain-ranges were again elevated 

 above the waves, whether rapidly in one or more convulsive throes, 

 or gradually during a long lapse of time, we may assume for 

 certain that violent disturbances both of land and water must 

 have taken place, of which our most vivid imagination will not 

 permit us to form any idea, or even to appreciate the extent. 

 The intervening space between these two regions, although not 

 elevated, must have been violently disturbed, and it is not difficult 

 to suppose the occurrence of one or the other of the two following 

 phenomena. 1. When the Eocene and Miocene formations were 



