318 PROP. HULL, LL.D., P.K.S., ON THE SUBMERGED TERRACES 



interpreting the phenomena of the Glacial Period ; for when we 

 conceive the British Islands lifted 6,000 or 7,000 feet higher 

 than at present, in reference to the present level of the sea, we can 

 easily see how glatnal conditions could take place. 



I have always been in favour of this explanation of glacial 

 phenomena rather than that given by Dr. Croll. But there may 

 be other forces that have had to do with the production of 

 great alterations of climate. We can easily conceive that a. con- 

 siderable elevation of land will lower the temperature very niuch 

 below that of the latitudinal climate or region ; but the depression 

 of any area of little elevation will not raise the temperature above 

 the latitudinal temperature of the region. We have had evidence 

 brought to us very recently from Fi'anz Josef Land of much 

 ^warmer climatic conditions having occurred there in the Jurassic 

 Period, for fossils show that the climate of that northern region 

 was then similar to the climate of the British Isles. 



In the paper I find it stated that it has been estimated that an 

 amount of water, lowering the surface of the ocean to the extent 

 of 2,000 feet, may have been locked up in the northern regions 

 during the Glacial Period. I am afraid I cannot agree with that. 

 I have estimated that, supposing the whole of the northern part 

 •of the globe north of the 50th pai'allel of latitude were covered 

 with an ice-cap, that ice-cap would have to be 10,000 feet thick 

 to lock up as much water as would lower the surface of the 

 ocean 2,000 feet. I cannot conceive an ice-cap of 10,000 feet 

 thick, for I do not see why ice should not have behaved in 

 the Glacial Period as it is behaving now ; and we find now that 

 the ice comes off the coast of Greenland in icebergs constantly, 

 and there is no reason why icebergs should not have come away 

 from the northern land area into the sea and have melted and so 

 restored, to some extent, the level of the sea. Therefore, I must 

 be allowed to diifer from that conclusion. It is not Professor 

 Hull's conclusion, but is merely a theory that has been advanced. 

 But generally it seems to be quite borne oat that the glacial 

 condition of the British Islands must have been largely dependent 

 on a very considerable elevation of the land ; and the way in 

 which Professor Hull has marked out the contours of the sur- 

 rounding sea bottom brings forward most cogent evidence in favour 

 of that hypothesis. 



Rev. F. A. Walker, D.D., F.L.S. — Looking back, with one's 

 mind's eye to the features of the country as it must have presented 



