518 Canadian Record of Science. 



and 3 marks the division between the trap and the unal- 

 tered Hmestone, the part covered by the latter being 

 shown by the space below the line, the Theralite by the 

 perpendicular lines, the altered limestone by the dotted 

 shading, and the crosses indicating Nepheline Syenite. 



On the map, Fig. 4, the shaded portion enclosed by the 

 heavy black line shows the position and general appear- 

 ance of the part occupied by the trap and altered lime- 

 stone, as referred to above. 



This part of the mountain as shown on the map is also 

 an irregular oval, with a length of about 9,000 feet from 

 East to West, by 5,700 in width, and having an approxi- 

 mate area of from 1,000 to 1,200 acres. This is somewhat 

 larger than that estimated by Logan, Geology of Canada, 

 p. 172, which he placed at about 700 acres. 



On the map, Fig. 4, it will be noted that the margin of 

 the dark portion is dotted, while the central part, 

 with a slight exception, is shaded in black. The 

 former is principally altered crystalline limestone, 

 with several heavy bands of JSTepheline Syenite, marked 

 by crosses, while the black represents the Theralite, 

 which forms the great mass of the mountain. 



From the map, Fig. 4, it will be seen that the crystal- 

 line limestone is found at the margin, almost completely 

 encircling the area occupied by the trap. Besides this, 

 there are a few small, isolated patches near the Park 

 Banker's house, and it is also found extending across the 

 lowest part of Mount Royal Cemetery, in the direction of 

 the Westmount outcrop, but it can only be traced where 

 excavations have been made, owing to a heavy covering of 

 drift. 



At the northern end of the mountain, the altered lime- 

 stone passes in several places under the road near the 

 Incline Railway, where it is 410 feet above the river. 

 Further south, the Syenite appears at one point beyond 

 the look-out, while on Westmount almost the whole of 



