Miles and 
kilometres. 
93°7 m. 
86-4 km. 
7A: 2 mi: 
119:4 km. 
Zz 
action of pressure on the rock, the larger in- 
dividuals of the constituent minerals being 
twisted, broken and granulated. This occur- 
rence is on a line of movement in the anorthosite. 
Ste. Marguerite—Alt. 900 ft. (274-3 m.) 
St. Jér6me—Alt. 308 ft. (93-9 m.) The 
train now returns to St. Jerome. A small 
isolated area of gabbro occurs in the Laurentian 
gneiss at this locality. It is much richer in 
iron magnesia constituents than the normal 
anorthosite of the Morin area. It is well 
exposed on either side of the railway track 
a few hundred yards south of the Canadian 
Pacific Railway station. 
Here the rock is fine in grain, usually foliated 
and weathers brownish-grey. In some places 
it possesses a more or less distinctly banded 
structure, due to the alternation of portions 
rather rich in bisilicates with others consisting 
almost entirely of plagioclase. Individuals of 
dark coloured plagioclase, usually small in size, 
but sometimes as much as six inches in length, 
are abundant in places. They are frequently 
curved or twisted, and are usually without good 
crystalline outlines. 
Under the microscope, the rock is seen to be 
composed essentially of plagioclase and pyroxene 
the former preponderating largely, with horn- 
blende, biotite, garnet, iron ore and pyrite as 
accessory constituents, and with a few grains of © 
quartz, calcite, chlorite and apatite. The pyro- 
xene is light green in colour, and is for the most 
part augite, which is often decomposed to calcite 
and chlorite. Some of it, however, is tiichroic, 
in red, yellow and green tints, and is probably 
hypersthene. The hornblende, which is green 
in colour, and the biotite are present in but very 
small amounts. The garnet is pink and per- 
fectly isotropic; it is often well crystallized and 
usually has some approximation to good crys- 
talline form. It is generally associated with the 
iron ore which is often present in considerable 
amount. As in certain parts of the Morin 
