314 PROF. HULL, LL.D., F.E.S., ON THK SUBMERGED TERRACES 



about glacial conditions in the north temperate zone, es- 

 pecially when combined with alterations in the temperature 

 of the Gulf Stream. On these points the reader is referred 

 to my former communication, and I shall only add here, that 

 the conclusions which 1 ventured to annunciate on the basis 

 of the statements of previous authors have been fully verified 

 by my own study of the Admiralty charts, which I have 

 here communicated to the Institute.* 



VIII. The great rise and jail of the land, by ichat standard 

 to he measured. — The question of a rise and subsequent de- 

 pression of the British and adjoining Continental areas, such 

 as is here postulated — amounting to about 9,000 feet — may 

 well cause not only surprise, but also some doubt in the 

 minds of many; but their hesitation may find some relief 

 from two or three considerations : — 



(1) We have unquestionable evidence that late Tertiary 

 strata of marine origin are found in the Alps and other 

 regions at elevations of 10,000 feet, and over, above the sea. 



(2) The probability that during the Glacial period large 

 quantities of oceanic water were locked up in the form of 

 snow and ice round the North Pole as supposed by the late 

 Mr. A. Tylor,t and apparently concurred in by Dr. A. Wallace. 

 Mr. Tylor estimated that the amount of water thus locked 

 up Avould have lowered the surface of the ocean by 2,000 

 feet. On the other hand, a general lowering of the 

 surface may have been brought about by depressions in the 

 bed of the great oceans as suggested by Professor Suess.t 



(3) In trying to reahze such great changes of level we 

 must recollect that as regards the standard of measurement, 

 namely, the diameter of the globe, they are really insignifi- 

 cant. Even a rise or fall of the surface, to the extent of 

 10,000 feet, will only amount to ^^^th part of the diameter. 

 AVe do not postulate a gTeater rise or fall than about 1,200- 



* Professor T. McK. Hughes, in his interesting paper on The Evidence 

 of Later Movements of Elevation and Depression in the British Isles, read 

 before the Institute in 1879, postulates a rise of tlie land to the extent of 

 several thovisand feet and infers the climatic changes which would thence 

 result. I hope he will now concur with me that such a rise has actually 

 taken place. — E. H. 



t Trans. Nova Scotia Institute of Natural Science, 1866. 



X There are other ways, more or less speculative, by which the 

 alteration of the general level of the ocean may have been brought about, 

 and which the reader will find described in Professor J. Geikie's com- 

 prehensive address already referred to. Loc. cit., p. 639. 



