ISOSTATIC MOVEMENTS OFF NEW ENGLAND COAST 307 



Students of the glaciated area are also in fair agreement as to a pro- 

 longed lag in the uplift of the continental part of it, though there may 

 have been some uplift before the Labrador ice-cap disappeared. A similar 

 lag is evident in the uplift of Scandinavia after its deglaciation. De Geer 

 holds that the crustal sinking in Scandinavia continued even after the 

 ice had melted off from southern Sweden."^ 



Probably New England had lost its general ice-covering by the time 

 Atlantic water commenced to wash the hills around Ottawa, Canada, at 

 elevations now 600 or more feet above sea. Incidentally, it may be 

 observed that this lag in uplift is not consonant with the explanation by 

 purely elastic resilience, for uplift so caused should have begun imme- 

 diately after unloading. 



Meanwhile, however, the ocean-level was doubtless rising because of the 

 return of water to the ocean through melting — a rise which more and 

 more masked the local sinking of sealevel because of the weakening of 

 the gravitative pull exerted by the diminishing glacier. The coast region 

 may have been thus drowned to the extent of 150 to 200 feet.^ 



Another considerable part of post- Wisconsin time was occupied by the 

 gradual uplift. 



Clearly, therefore, the highest strand in Maine could have been beaten 

 by waves during but a small portion of the period elapsing since the 

 Wisconsin ice began to disappear. The upper part of the emerged belt 

 was washed first by an advancing sea and then by a retreating sea. The 

 total time involved was not a great many thousands of years. Under 

 the circumstances, strong and continuous terraces would not be expected. 

 Supplemented by the postulate of eustatic shifting of sealevel, the pre- 

 vailing explanation of the weakness of the strand-marks is unquestion- 

 ably correct in principle. Yet it is not the full explanation. 



From Belle Isle Strait to Nachvak Bay, on the northeast coast of 

 Labrador, a distance of 600 miles, the evidences of energetic wave-action 

 in the emerged belt are much stronger than in the emerged belt of New 



^ W. A. Johnston : Memoir 101, Geol. Survey of Canada, 1917, p, 30. 

 W. Upham : Monograph 2,5, U. S. G^ol. Survey, 1895, pp. 235 and 499. 



F. B. Taylor : Monograph 53, U. S. Geo]. Survey, 1915, pp. 330, 506-7. 



G. De Geer : Bull, Geol. Soc. Am., vol. 3, 1892, p. 65, and Compte Rendu, Cong. geol. 

 internat., Stockholm, vol. 2, 1910, p. 849. 



Brogger believes that the Christiania region began to sink to an ultimate amount of 

 240 meters when the Scandinavian ice-cap began to melt. His evidence is by no means 

 convincing. Moreover, he did not consider the effect of ice-melting in raising general 

 sealevel. Norges geol. Unders., no. 31, 1901, pp. 690-1. 



8 Johnston is inclined to make the eustatic rise yet greater at Ottawa, Canada. With 

 W. B. Wright, he ascribes to this movement the late Glacial submergence of Norway, 

 which Brogger had attributed to crustal sinking. The Quaternary Ice Age, London, 

 1914, p. 414. 



