110 P'^^of. Hughes, Criticism of the Geological [Oct. 30, 



of Biarritz, No. 20, we have the same facets, the same polish, the 

 same fretted surface due to the eating away of the softer parts 

 by the sand and the consequent relief of the veined or harder 

 portion. 



Now to turn to the Swiss valleys where it is known that the 

 glaciers once extended far beyond their present limits and where 

 their constantly recurring advance and recession within the memory 

 of man is certain. What limit can we place upon this oscillation ? 

 If earth movements are going on, if climatal changes are taking 

 place, the alteration in the volume of ice must be of the same 

 kind but greater in degree than what is observed from half-century 

 to half-century as the result of what we call weather. What 

 wonder then that in the basin around Zurich, which the ancient 

 larger lake once filled, we should find moraines above peat and 

 older morainic debris below. I am satisfied as to the fact. I worked 

 for two hours under ground in the lignite pit till I found for my- 

 self undoubted glacially scratched stones, e.g. No. 68, which is 

 identical with those that were found above, e.g. No. 69. But what 

 has this to do with secularly recurring cold periods ? It is only on 

 a larger scale and belonging to an older time what the guides will 

 point out as having occurred within their own memory at the foot 

 of the Rhone glacier. 



X. Tertiary Glaciers. 



Of earlier Tertiary age we will take as an example the Miocene 

 deposited on the south of the Alps which Gastaldi argues has 

 evidence of glacial action not only in the character of the deposit 

 but also in the occurrence of glaciated stones. Admitting the 

 accuracy of the observations on which these views are founded, 

 and, though I have been over the ground I have nothing to say 

 for or against them, it is not remarkable to find glaciers in ancient 

 times where there have been glaciers in recent times unless we 

 hold that the last upheaval which raised and left the Alps where 

 they now are was the only great upheaval of which we have any 

 knowledge. That has through many successive periods been an 

 axis of greatest movement, and the higher it was raised the 

 greater, cseteris paribus, must its glacier ice have been. This 

 question of earth movement and its bearing on glacial phenomena 

 I will ask leave to bring before the Society on some other occasion. 



xi. Boulders in Cretaceous Rocks. 



Of still earlier date are the blocks of coal and boulders of 

 granite found in the Chalk for instance or the large masses of 

 gneissic and other rocks found in the Cambridge Greensand or 

 the Potton Beds. Among these we have from the Cambridge 



