298 



JOSEPH BARRELL 



the value of the actually observed deflections. The surface may be 

 regarded, therefore, as nine-tenths compensated by variations of 

 density. The details for the five more significant groups are 

 given below :^ 



TABLE XX 



Group 12 gives the greatest depth for uniform compensation. 

 By using the residual for Solution E, 2.09, the percentage of 

 completeness of compensation would have been 75, a trifle more 

 than for Solution H, but still next to the least perfect in the United 

 States. 



Group 8, the Great Basin region, has the lowest depth of com- 

 pensation but shows about the average approximation to isostatic 

 equilibrium. 



Groups 10, 9, 14 comprise the Pacific Coast Ranges. They give 

 the highest topographic deflections of the United States, doubtless 

 on account of the great relief of the ocean basin and continental 

 border, but the actually observed deflections do not dift'er greatly 

 from group 8 or the mean for the whole United States. The result 

 is that in this mountain region bordering the continent the degree 



^ Taken from pp. 56, 58, 69, and illustration No. 2, Hayford, 1909. 



