164 ¥.D. ADAMS—NODULAR GRANITE FROM PINE LAKE, ONTARIO. 
but rudely parallel streaks, differing from one another somewhat in size 
of grain. Where this gneissic structure is seen, it coincides in direction 
with the strike of the associated amphibolitic rock, which in places is 
also foliated. Much of the granite resembles aplite in appearance, but 
in places it passes into a coarse pegmatitic development, holding large 
masses of black schorl. Its general character, except for these minor 
variations, is uniform over a very considerable tract of country, and its 
appearance is that of an undoubted igneous intrusion. 
The nodules described in the present paper do not occur throughout 
the whole mass of the granite, but are confined to a portion of it, which, 
although situated toward the northern limit, is from 200 to 300 yards 
from its contact with the amphibolite, so that the nodular development 
cannot be regarded as a contact phenomenon. Along the contact, the 
granite is in fact free from nodules. The localities where the nodules 
have been found are all situated on Range III of the township of Cardiff, 
being chiefly on Lots 15 and 15, which lie opposite to one another on the 
north and south sides of Pine lake, respectively. They are also found 
to the northeast of the lake, at a point probably about Lot 18 of the 
same range. In these localities the nodules are abundantly dissemi- 
nated through the rock, although not thickly crowded together as in 
many other similar occurrences elsewhere described. Where most abun- 
dant 200 were counted ona surface 36 square feet in 1 extent. Elsewhere 
they are much less numerous. 
They are usually spherical in form, but in some places have a more 
or less flattened or elliptical outline. This is more especially the case 
where the granite shows a tendency to foliation, the longer axes of the 
nodules in this case being parallel with the strike of the rock (see plate 
11, figure 2). The nodules have a diameter of from one to eight inches, 
but usually measure from two to three inches across and can readily be 
broken out of the rock entire and almost free from the surrounding ma- 
trix. Those of them which have been cut across and smoothed by the 
glaciation of the country show the inner portion of the nodule to be 
lighter in color than the normal granite. 
Being harder and more resistent than the granite, furthermore, they 
stand out a little from its somewhat disintegrated surface. Many of the 
nodules when thus ground flat by the action of the ice also exhibit a 
more or less distinct zonal structure, the central portion being somewhat 
different in composition from the exterior, although this is not always 
seen. There is, moreover, usually a little bunch or sponge of black tour- 
maline near the center, while large glistening poikilitic plates of musco- 
vite are often seen. 
Although throughout the greater part of the area in which they occur 
these nodules are scattered haphazard through the rock without any def- 
