272 Buell—Geology of the Waterloo Quartzite Area. 
posure, are evidences of strong orographic movements in. 
the area. 
The rock is throughout a quartzite becoming conglomeratic in 
portions of the Portland area. Magnetite and zircon occur 
sparingly as primary inclusions, while sericite is a somewhat 
important secondary development in some types. 
The microscopic examination of the sections reveals much 
deformation of the quartz. The ditrital character of the rock 
has been nearly obliterated by the crushing and re¬ 
cementing of the quartz grains. Sericite has been developed 
through this means. Differences in composition and degree of 
metamorphism have produced four tolerably distinct types of 
quartzite, the recognition of which in the fragments composing 
the bowlder trains is of great assistance in defining their 
distribution. These correspond with the isolated areas 
of outcrops and are described under the names Port¬ 
land Type, Hubbellton Type, Red Quartzite and Mud Lake 
Type. Miscroscopically the distinctions lie in the relative 
coarseness of texture, the amount of granulation of quartz, the 
relative development of secondary sericite and the way in 
which the larger quartz fragments join one another—whether by 
locking together without interstitial material like the sutures of a 
skull, or cemented by a larger or smaller amount of finely 
granulated quartz and sericite. While the differences in these 
respects are not always great, they nevertheless suffice in most 
cases for the indentification of a specimen with some one of the' 
exposure areas. Corresponding with the microscopic differ¬ 
ences, are variations in the aspect of the rock which seem slight 
at first and are difficult to describe, but which from long 
familiarity come to have distinguishing value. 
From a comparison of structural features found in these rocks 
with Huronian quartzites from the areas of their occurrence to 
the north and northeast of this region the deduction is reached 
that the former present distinctive features of sufficient value 
to lead to their recognition. 
Familiarity with these differences is of great assistance as 
affording criteria for separation of the quartzite drift from the 
Waterloo area, from bowlder material from any of these other- 
