17 
pressure; and the circumstance that the streaks or irregular 
bands, when present in the otherwise massive rock, 
assume no definite direction, but twist about as if owing 
to the movements of the rock while in a pasty condition, 
indicates that they have been produced by movements 
befure the rock became solid. The unequal distribution 
of the constituent minerals in the rock, must have resulted 
either from irregularities in the composition of the original 
magma, or from processes of segregation at work in the 
magma during cooling and crystallization. 
On the other hand, the granulation of the coarsely 
crystalline massive anorthosite, usually with concomitant 
development of a more or less distinctly foliated or schis- 
tose structure in the way described, is undoubtedly due 
to movements in the rock, resulting from pressure which 
acted subsequent to or possibly during the last stages of 
its solidification, for, as has been shown, the granulation 
begins to make its appearance in the massive crystalline 
rock itself. Under the influence of pressure, the massive 
rock gradually gave way, and the movements resulted tn 
granulation. Moreover, wherever these movements con- 
tinued longest or were most intense, this granulation 
became most complete, until finally the last remnants 
of the larger individuals disappeared, and in the case of 
a pure anorthosite, a more or less evenly granular rock 
resulted. In the anorthosite, however, the remnants of 
larger individuals are seldom or never entirely absent, 
and over the greater part of the area the amount of 
interstitial material is quite small. 
ANNOTATED GUIDE. 
poe and 
<llometres. 
0-0 Montreal—Place Viger Station—Altitude, 
HOLA fit. 117-6 11.) 
5-I m. Mile End—Altitude 225 ft. (68-5 m.) 
8-2km. Leaving Place Viger station, the railway 
passes along the north bank of the St. Law- 
rence river and then through the western 
portion of the city, which is underlain by the 
limestones of the Trenton fo1 mation (Ordovician) 
which are here about 600 feet, thick. The in- 
trusive mass of Mount Royal (one of the Mon- 
teregian hills) composed of essexite and nepheline 
32224—2 
