THE ACCORDANCE OF SUMMIT LEVELS AMONG ALPINE 

 MOUNTAINS : THE FACT AND ITS SIGNIFICANCE 1 



REGINALD A. DALY 



Ottawa, Canada 



CONTENTS 



The Statement of Summit -Level Accordance. 

 The Various Explanations of Accordance. 

 I. Explanations by Inheritance. 

 i. The peneplain theory. 



2. Hypothesis of "original" rough accordance of summit levels, due 

 to isostatic adjustment. 



3. Hypothesis of "original" rough accordance, due to differential 

 erosion during the period of alpine plication. 



4. Conclusion. The Composite Explanation. 



II. The Spontaneous Development of Summit-Level Accordance. 



1. Spontaneous development by isostatic adjustment. 



2. Metamorphism and igneous intrusion in relation to the degrada- 

 tion of mountains. 



3. The influence of local glaciation on summit altitudes. 



4. The influence of the forest cap on summit altitudes. 



5. Accordance through river-spacing and gradation of slopes. 

 General Conclusion and Summary. 



THE STATEMENT OF SUMMIT-LEVEL ACCORDANCE 



Neither statistics nor eloquence are required to recall one prin- 

 ciple in the interpretation of lofty, alpine mountains; their student 

 must be content to attack their mighty problem in a piecemeal fashion. 

 The alps of the world are tangles in structure and the stony records 

 of tangles of prodigious events. It is no wonder that their form has 

 so long baffled the evolutionist. He has often had to turn back 

 from the attempt to carry into the high mountains the same ground 

 principles of land-building and land sculpture which have of late 

 years been so successfully explaining the simpler forms of the land. 



1 Published by permission of the Canadian commissioner, International Boundary 

 Surveys. 



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