126 E. A. Daly — Mechanics of Igneous Intrusion. 



areas of the globe may not be related to that process of found- 

 ering in its latest, local j^hase. The refrigeration of the planet 

 must have progressed so far even in the Cambrian period 

 as to prevent a recurrence of life-destroying, world-circling 

 catastrophe. In others words, the possibility of foundering 

 depends, according to Kelvin's view, among other things, 

 upon the amount of residual heat within the earth. By the 

 same view the Nelson batholith takes its place among the post- 

 Archean batholiths which may be believed to have penetrated 

 a crust already sufficiently buttressed through secular cooling 

 so as to withstand the strain due to the differential density of 

 vault and molten batholith. Other general considerations rela- 

 tive to the problem have already been presented in the writer's 

 first paper. All of them are offered rather to emphasize once 

 more the difficulty and importance of the problem than to sug- 

 gest that a complete solution has been found. 



Geological Survey of Canada, Ottawa, Canada. 



