SULLEfJN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 21, pp. 717-730 December 24, 1910 



SOME EFFECTS OF GLACIAL ACTION IN ICELAND^ 



BY FRED. EUGENE WRIGHT 



{Read before the Society December 28, 1909) 



CONTENTS 



Page 



Introduction 717 



Features of valley glacier erosion 719 



Ice as an erosive agent 719 



The ice-flood period 719 



Features resulting from the action of a single valley glacier 720 



Features developed at junctions of tributary glaciers with trunk 



glacier 721 



Hanging valleys 721 



Glacier junction basins 721 



Glacier junction spurs 721 



Glacier junction deposits 722 



Features of ice-cap erosion 723 



Ice-cap beveling 723 



The upland surface in Iceland 724 



The uplands of the Coast Range, Alaska 725 



Cycle of ice erosion 726 



The field problem 727 



Summary 728 



Introduction" 



The dominant geological features of Iceland are its glaciers and its 

 volcanoes, both of which are developed on a tremendous scale and afford 

 unusual opportunities for detailed study. The island itself is essentially 

 an uplifted plateau country, averaging 500 to 700 meters in elevation, 

 and consisting in large part of basaltic lava . flows and associated tuffs 

 and breccias. Fringing this plateau at different points are lowland 

 coastal strips, whose total area is nearly one-fifteenth of that of the 

 entire island; to these all habitation is practically confined, the rest of 



1 Manuscript received by the Secretary of the Society September 21, 1910. 



L— Bull. Geol. Soc. Am., Vol. 21, 1909 (717) 



