7«4 



W. G. FOYE 



Grenville series represents a series of altered sediments of Laurentian, Huro- 

 nian, or subsequent age. 1 



Adams in the same article stated that the last hypothesis was 

 untenable. 



The world-wide distribution of the Fundamental Gneiss (forming, as it 

 does, wherever the base of the geological column is exposed to view, the founda- 

 tion upon which all subsequent rocks are seen to rest) is opposed to this view 



as is also its persistent gneissic or 

 banded character. 2 



Later, in 1897, Adams altered 

 his earlier view. He writes : 



The batholiths are undoubtedly 

 formed by an uprising of the granitic 

 magma from below, and these foci 

 indicate the axes of greatest upward 

 movement. These centers are not all 

 areas of most rapid uplift, however. 

 On the contrary, the gneissic foliation 

 in some cases dips inward in all direc- 

 tions toward the center, thus marking 

 them as places where the uprise of the 

 magma was impeded, that is to say, 

 places where the overlying strata have 

 sagged down into the granite magma. 3 



Fig. i. — Map of the corundum syneite 

 district of Craigmont, Ontario. 



Black, limestone; white, amphibolite; 

 dashed, gneissic granite; dotted, gneissic 

 granite with amphibolitic inclusion. 



A striking fact concerning 

 these so-called batholiths is that 

 they do not cut across the struc- 

 ture of the invaded rocks, a 

 fundamental characteristic by which post-Cambrian batholiths are 

 recognized. While it is true that there are bodies within the district 

 which cut across the structure of the country rock, they are unusual, 

 and concordant relationships are much more common. 



A glance at the map (Fig. 1) which shows the corundum 

 syenite district of Craigmont, Ontario, makes clear the concentric 

 arrangement of the sedimentary rocks within the gneiss areas. 



1 Journal of Geology, I (1893), 330-32. 



2 Op. cit., 332. 3 Am. Jour. Sci., Ill (1897), 173-80. 



