THE STRENGTH OF THE EARTH'S CRUST 



JOSEPH BARRELL 



New Haven, Connecticut 



Preface 



PART I. GEOLOGIC TESTS OF THE LIMITS OF STRENGTH 



Introductory and Summary 29 



Mountains Built by Compression or Igneous Activity ... 32 



Shiftings of Load Due to Climatic Change 33 



The Evidence from Erosion Cycles 34 



The Evldence from Deposition 36 



Preliminary Statement 36 



The Deltas of the Nile and Niger 39 



Discussion of Results 43 



PREFACE 



The publication of a series of papers on " Diastrophism and the 

 Formative Processes" by T. C. ChamberHn was begun in the 

 Journal of Geology in October, 1913. The second part, on "Shelf- 

 Seas and Certain Limitations of Diastrophism," is nearly identical 

 in substance with a portion of a paper read by Professor Chamberlin 

 on August 13, 1913, at the Twelfth International Geological Con- 

 vention at Toronto, Canada. In this part particularly it is pointed 

 out that the parallel surface and bottom of the shelf-seas, also their 

 occasional extension as shallow water bodies over considerable por- 

 tions of the continent at certain times, indicate a relation to sea- 

 level and wave base rather than to a delicate isostatic adjustment. 

 The implications of this and other lines of argument given by 

 Chamberlin are toward crustal rigidity, not crustal mobility. 



The first four parts of the present article on "The Strength of 

 the Earth's Crust" had been completed before the writer read Pro- 

 fessor Chamberlin's paper, or knew that he was at work upon the 

 subject; but the conclusions are so closely in accord with his, 

 though reached by other lines of attack, that this article may be 



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