Mount Royal Once an Active Volcano 339 



containing the story of the Mountain have for the most 

 part been swept away by the action of the elements 

 during the immense period of time which has elapsed 

 since the forces that brought the Mountain into existence 

 were in action. 



In the paper in question, it was noted that while it 

 did not amount to a certainty, the evidence on the whole, 

 and particularly the nature of the Essexite forming the 

 Mountain which indicated that it had cooled at depth, 

 tend to show that Mount Royal, or at least that part of 

 it which now forms the mass of the Mountain, had not 

 been an active Volcano, that the Mountain as we see it 

 to-day was a lacolite, a mass of hardened trap, which 

 while in a state of fusion filled a great subterranean 

 cavity, or to be more exact, several distinct cavities which 

 did not reach the surface, and which owing to its hard- 

 ness remained when the softer limestone by which it was 

 covered had disappeared through the action of the 

 elements. 



In support of this opinion, it seems to me the evi- 

 dence still stands, as regards the great mass of the Moun- 

 tain as it appears to an observer from what may be called 

 the outside, but when it is examined from certain points 

 on the summit, there is room for the opinion that there 

 may also have been active conditions present, that what 

 we know as the Mountain now, was only part of the 

 movement, and that there may at some time have been 

 great volcanic activity connected with it. 



This brings us to a consideration of what may be 

 called the further evidence bearing on the question. To 

 an observer placed at certain points on the top of the 

 Mountain, it will be seen that there are three principal 

 peaks, one on the northeastern side, one to the southwest 

 and the "Westmount or Little Mountain which is still a 

 covered lacolite, and that these elevations enclose a prac- 

 tically level plain, over 200 feet below their present sum- 

 mits, in which are included the Mount Royal and Cote 

 des Neiges Cemeteries, the field near the Park Ranger's 



