BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 31, pp. 303-318. PL. 14 June 30, 1920 



OSCILLATIONS OF LEVEL IN THE BELTS PEEIPHERAL TO 

 THE PLEISTOCENE ICE-CAPS ' 



BY REGINALD A. DALY 



(Presented in abstract before the Society December 29, 1919) 



CONTENTS 



Page 



A test of isostasy ^^^ 



Evidence of isostatic movements off the New England coast 305 



Isobases ^^^ 



Weak wave erosion in the emerged zone • 305 



Conclusion 309 



Evidence from the marginal belt west of New Engldnd 310 



Scope of the discussion 310 



Abandoned lake strands 311 



Submarine Hudson channel 312 



Susquehanna "deeps" 313 



Drainage changes in the Ohio Valley and farther west 314 



Evidence from Europe 317 



Summary 318 



A Test of Isostasy 



The theory of isostasy is Avidely favored as an explanation of recent 

 uplifts in the glaciated tracts of North America and Europe. If the 

 earth's crust sinks after a heavy, extensive load of ice is put on it, and 

 rises after that ice melts; if the crust so behaves each time that one and 

 the same region is glaciated and deglaciated; if similar behavior were 

 proved in separate areas — eastern Canada, the British Isles, Scandinavia, 

 British Columbia, Patagonia, and Antarctica — the theory would almost 

 become certainty. As a matter of fact, field studies have been largely 

 confined to but three of the greater ice-cap areas and in each case to uplift 

 following the latest deglaciation. Complete testing of the isostatic theory 

 after the manner described is evidently much more difficult than the 

 partial te.st so far applied. 



1 Manuscript received by the Secretary of the Society December 29, 1919. 



XXI— Bull. Grol. Soc. Am., Vol. .'il, 1919 (303) 



