VOLUME XXII NUMBER 5 



THE 



JOURNAL OF GEOLOGY 



JULY-AUGUST 1Q14 



THE STRENGTH OF THE EARTH'S CRUST 



JOSEPH BARRELL 



New Haven, Connecticut 



PART V. THE DEPTH OF MASSES .'PRODUCING GRAVITY 

 ANOMALIES AND DEFLECTION RESIDUALS 



Introduction and Summary ... . . ... 441 



SECTION A^ 



Development of Criteria for Spheroidal Masses .... 446 



Separation of Lithospheric from Centrospheric Outstanding Masses 446 



Influence of Centrospheric Heterogeneity 448 



Distribution of Surface Forces for Centrospheric Spheres . 449 

 Influence of Spheres within the Zone of Compensation . -452 

 Influence of Sum of Intersecting Spheres Approximately Equivalent 



to Spheroids 453 



Distinctive Effects of Individual Spheres and Spheroids . . . 458 

 Depths of Spheres Whose Epicenters Are Not on the Line of 



Traverse 463 



INTRODUCTION AND SUMMARY 



The fact that the observed deflections of the vertical are on 

 the average only one-tenth as large as the computed effects of the 

 topographic relief, computed on the assumption of uniform density 

 throughout each earth shell, shows that the densities of the crust 



^ Section B of Part V, on the applications of the criteria to determine the limiting 

 depths, forms, and masses of the excesses and defects of density, will be published in 

 the following number of this Journal. 



Vol. XXII, No. 5 441' 



