﻿312 Canadian Record of Science, 



relations as given above is correct, the Laurentian system 

 of Logan will resolve itself into an enormous area of the 

 Fundamental Gneiss, which is essentially of igneous 

 origin and which there is every reason to believe forms 

 part of the downward extension of the original crust 

 of our planet, perhaps many times remelted and certainly 

 in many places penetrated by enormous intrusions of 

 later date ; into which Fundamental Gneiss, when in a 

 softened condition, there have sunk portions of an over- 

 lying series, consisting chiefly of limestones. 



Farther east, in that portion of the Province of Quebec 

 where the Grenville series was first studied by Logan, the 

 rocks of the Hastings series proper have not been 

 recognized. The Lower Paleozoic strata rest directly 

 upon the Grenville series and would cover up the 

 Hastings series to the south should it extend as far east as 

 this. The limestones of the Grenville series, moreover, 

 here extend much farther back from the edge of the 

 protaxis in bands and streaks conforming to the strike of 

 the underlying gneissic rocks, so that the origin of 

 the series and its relations to the Fundamental Gneiss is 

 not so clearly indicated. When, however, its relations 

 here are interpreted in the light of the Ontario occurrences, 

 there seems to be no reason why the same explanation 

 might not be offered to account for its origin also. The 

 bands of limestone, which often vary in thickness from 

 place to place, and are frequently interrupted in their 

 course or abruptly cut off, might be considered as having 

 taken their form from long folds in the series from which 

 they were derived as it settled down into the magma 

 beneath, or as having been separated by great lateral 

 intrusions of the gneissic magma. Their original shape 

 and character has, however, without doubt been greatly 

 altered by the enormous movements to which both series 

 of rocks have been subsequently subjected. 



If again this proves to be the true explanation of 



