642 LEWIS G. WESTGATE 
3. Inclusions.— One of the most striking proofs of the eruptive 
character of the granite-gneiss is the presence of inclusions of 
schist within its boundary. These are seen at a number of 
localities in widely different parts of the area, and commonly 
not far from the border (Map, 4). They vary in size from a few 
inches to many feet in length, and may be of linear or very 
irregular form. The material composing them is a biotite-schist, 
or a fine-grained biotite-gneiss, similar to the schist series around 
the gneiss and often showing the minute folding which in places 
is characteristic of the latter. The inclusions occur both in the 
more massive and in the more foliated varieties of the granite- 
gneiss, and also in the granulitic facies which occurs at some 
points about the border. 
At this point it is well to describe an occurrence which, 
while not a proof of the igneous origin of the granite-gneiss, 
is best understood in connection with inclusions. At several 
localities in the southern half of the granite area, occur isolated 
bands of schist of uniform thickness, running parallel to the 
foliation of the immediately adjacent granite-gneiss. They 
cease at a greater or less distance, but their actual termination 
cannot be seen because of lack of outcrops. They show sharp 
contacts with the enclosing granite-gneiss and in one or two 
cases tongues of the latter enter them at a low angle, 
showing them to be inclusions. And as even those schist bands 
which do not show an apparent eruptive contact lie within an 
area of rock which is certainly in largest part eruptive, it is most 
likely that all such occurrences are inclusions. - These band-like 
inclusions vary from a few feet to several score of feet in thick- 
ness, and are sometimes several hundred feet in length. Their 
direction is variable and is independent of the foliation of the 
schist lying nearest to them outside of the granite-gneiss area. 
Their sheet-like character was evidently determined by the 
strong foliation of the schists through which the granite-gneiss is 
here eruptive. It is, however, along the east side of the granite- 
gneiss that the amount of this foreign material is greatest. 
Here the mica-schist is associated with considerable dark, 
