﻿Origin of the Grenville and Hasting e Series. 309 



western corner of the area, in llie townships of Lutter- 

 worth, Snowdon and Glamorgan, while in the southern 

 and south-eastern portions of the area there are other 

 occurrences, which, however, present a more normally 

 granitic character. 



The south-eastern portion of the area is underlain by 

 rocks of the so-called Hastings Series, consisting chiefly of 

 thinly-bedded limestones, dolomites, etc., cut through by 

 great intrusions of gabbro-diorite and granite. These 

 limestones and dolomites are usually line-grained and 

 bluish or greyish in color, with thin interstratified layers, 

 holding sheaf-like bundles of hornblende crystals. As 

 compared with the limestones of the Grenville series they 

 are comparatively unaltered. They form beyond all 

 doubt a true sedimentary series, and in the south-eastern 

 corner of the area are associated with conglomerates 

 or breccias of undoubtedly clastic origin. Between the 

 great area of Fundamental Gneiss in the north-west, and 

 the Hastings series in the south-east of the sheet, there 

 lies an irregular-shaped belt of rocks, presenting the 

 characters of the typical Grenville series as above 

 described, the limestones having in all cases the form 

 of coarsely crystalline, white or pinkish marbles, although 

 more or less impure. The strike of the foliation of the 

 Grenville series follows in a general way the boundaries of 

 the Fundamental Gneiss, and is seen in an especially 

 distinct manner to wrap itself around the long and 

 narrow development of the gneiss exposed in the south- 

 west corner of the area. Isolated masses of the limestone 

 and gneiss characteristic of the Grenville series are also 

 found in the form of outlying patches about its margin, 

 as, for instance, in the townships of Lutterworth and 

 Stanhope. The relations of the Grenville series to the 

 Fundamental Gneiss are such as to suggest that in the 

 former we have a sedimentary series later in date than the 

 Fundamental Gneiss, which has sunk down into and been 



