I 
) 
i 240 COMPTE-RENDU. QUATRIEME PARTIE 
I for the cold and snowy climate producing’ the ice-slieet, The 
^ belief that this uplift was 3000 feet or more, giving sufficiently 
' cool climate (as we inay infer from Prof. T. G. Bonney’s com- 
putations for the requisite general lowering of the température) 
I to cause the ice accumulation, has been only reached within the 
f past fcw years by Spencer, Le Conte, Hilgard, and the présent 
writer, through the discovery, by soundings of the U. S. Coast 
Survey, thaï on both the Atlantic and Pacific coasts of the 
] United States submarine valleys evidently eroded in late Ter- 
tiary and Quaternary time reach to profound depllis, 2000 to 
; 3000 feet below the présent sea level L 
I Although the adequacy of the preglacial epeirogeiiic uplift of 
’ this continent to produce ils Pleistocene ice-sheel was so late in 
s being fully ascertained and accepted, it was distinctly claimed 
! by Dana in 1870, that the Champlain subsidence of the land be- 
I ncath its ice load, supposing it to bave been previously at a high 
altitude, must hâve brought climatic conditions under which the 
i ice would very rapidly disappear 
! Such explanations as these accounting far the graduai accu- 
^ mulation and comparalively rapid dissolution of the North Arne- 
' rican ice-sheel, are also found to be applicable to the ice-sheets 
■ of other régions. The fjords of the northern portions of the Brit- 
■ ish Isles and of Scandinavia show that the drift-bearing- north- 
western part of Europe stood in preglacial time 1000 to 
4000 feet higher than now, while on the other hand late glacial 
marine beds and strand lines of sea érosion testify thaï when 
the ice disappeared the land on which il had lain was depressed 
100 to 600 feet below its présent height, or nearly to the sanie 
, amount as the Champlain dépréssion in North America. Again, 
just the same évidences of abundant and deep fjords and of 
: marine beds overlying the glacial drift to heights of several 
; hundred feet above the sea are found in Patagonia, as describ- 
ed by Darwin and Agassiz. On these three continental areas, the 
widely separated chief drift-bearing régions of the earth are 
found to hâve experienced in connection with thcir glaciation, 
^ in each case, three great epcirogenic niovemenls of similar 
1 Detailed notes of these submerged valleys are presented in my paper ; On 
■ the Cause of the Glacial Period, Am. Geologist, vol. VI, p. 327-339, De- 
cember 1890. 
^ Trans., Connecticut Acad, of Arts and Sciences, vol. II, 1870, p. 67 ; Am. 
Jour. Sci., III, vol. X, p. 168-183, Sept., 1875. 
