41 
sodium. This conception is adequately expressed by Colony , 1 who says: 
“The effects produced within the igneous rock itself are due 
in part to reactions due to adjustments of equilibrium between the ex- 
treme end-stage, highly concentrated ‘mother liquid’ which, by selective 
freezing, has been enriched with the more volatile gases usually termed 
‘mineralizers’, among which water plays an important part, and the now 
almost wholly consolidated igneous rock.” He goes on to say: “At this 
stage much of the quartz and some of the alkalis, especially soda in such 
form as to appear ultimately as albite, seem to be concentrated in the 
form of a liquid consolidation-residuum, which, from such evidence as is 
presented in the rocks themselves, must possess an extremely low viscosity, 
great penetrating power, and considerable chemical activity.” From the 
study herein described, and especially from the widespread occurrence of 
the blue soda-amphibole, the writer suggests that this “consolidation 
residuum” may more closely approach, in some cases, a gaseous or pneu- 
matolytie state than the liquid condition assigned to it by Colony. 
‘Co'ony, R. J.: "The Final Consolidation Phenomena in the Crystallization of Igneous Rock”; Jour. Geol., 
toI. 31, p. 160 (1923). 
