79 
stratum or part. When the passage to the surface was 
opened up, the pulaskite would first rise in it, and, after 
a more or less continued flow, being followed by the essexite, 
would be pressed toward the circumference of the pipe, 
the more basic rock occupying the central portion of the 
passage, and the most basic variety, originally, lower would 
be found in the central axis of the neck. The fact that, 
while the essexite forms the mass of the intrusion, there 
is a zone of pulaskite about it, would seem to indicate 
that there had not been at this centre of volcanic activity 
any very protracted outpouring of the essexite, since, had 
this been the case, it would seem probable that the pipe 
would have, in time, been cleared of the upper pulaskite 
magma. 
BIBLIOGRAPHY OF THE MONTEREGAIN HILLS 
I. Adams, F. D....Ona Melilite-bearing Rock (alnoite) 
from Ste. Anne-de-Bellevue, near 
Montreal, Canada. Am. Jour. of 
Science, April 1892. 
2. ................1T he Monteregian Hills—A Canadian 
Petrographical Province. Journ. of 
| Geol., April 1903. 7 
3. Dresser, J. A....Report of the Geology and Petro- 
graphy of Shefford Mountain. Geol. 
Survey of Canada, 1903. 
J a ie i ier ee Report on the Geology of Brome 
Mountain, Quebec. Geol. Survey 
of Canada, 1906. 
pee ees bh Report on the Geology of St. Bruno 
Mountain (Quebec). Geol. Survey 
of Canada, IgIo. 
6. Evans, N. N....Native Arsenic from Montreal. Am. 
Jour. of Science, February 1903. 
7. Eve, A.5.&....The amont of Radium present in 
McIntosh, D. _ typical rocks in the immediate neigh- 
bourhood of Montreal. Bulletin of 
the Royal Society of Canada, June, 
1907. 
8. Harrington, B. J.On the Composition of some Mont- 
real Minerals. Trans. Roy. Soc. of 
Canada, October, 1905. 
