BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 34, pp. 381-400 June so. 1923 



COiS^TRIBUTION TO THE HYPOTHESIS OF MOUNTAIN 



FORMATION ^ 



• BY E. C. ANDREWS 



{Presented before the Society December 29, 1922) 



CONTENTS 



Page 

 Introduction 381 



Distribution and arrangement of the present mountains of the earth 382 



Age of the existing mountains 384 



Distribution and arrangement of past mountain systems of the earth .... 385 



Structure of existing mountains 387 



Comparison of ranges 387 



The Himalaya 389 



American Cordillera 389 



European mountains 390 



African mountains 390 



Australian mountains 390 



Structure of past mountains .391 



Relation of areas of sedimentation to mountain ranges 392 



Some special features of Cenozoic mountains 393 



Relations of volcanoes, earthquakes, and of igneous intrusions to moun- 

 tain formation 394 



Earth waves and volcanoes 394 



Igneous intrusions 395 



Relation of heating of underlying folded sediments to mountain formation 396 



Relation of isostasy to mountain formation 396 



Summary and conclusions, 397 



Introduction 



An examination of the Broken Hill district in New South Wales has 

 suggested to the writer the advisability of attempting a tentative correla- 

 tion of observations made by him during recent years within the moun- 

 tain areas of Australia, New Zealand, Fiji, British Columbia, and the 

 United States. The article presented herewith may be found to be of 

 some assistance to those who have studied the formation of mountains. 



^ Manuscript recpivfd by the Secretary of the Society August 9, 1922. 



(381) 



