Illustrations. 
Page 
Plate L Black lake Frontispiece 
II. North end of Black lake 83 
III. Granitic intrusion in peridotite, Hall chrome pit 85 
IV. Ridges of serpentinized peridotite, Black lake 87 
V. Chromite pocket, Hall chrome pit . 89 
VI. Montreal chrome pita 91 
VII. Main Montreal chrome pit. 93 
VIII. A. Microphotograpb of white diopside rock, natural light 95 
B. Dump of the Standard Asbestos mine. 95 
IX. A and B. Microphotographs of ropes of garnet in teldspar in a 
garnetiferous aplite, natural light 97 
X. A. Microphotograph of radiated vesuvianite with diopside, 
natural light 99 
B. Microphotograph of radiated vesuvianite with diopside, 
polarized light 99 
XI. A. Microphotograph showing drusy character of colerainite-bearing 
rock, natural light 101 
B. M icro photograph showing drusy character of colerainite-bear- 
ing rock, polarized light 101 
XII. Microphotographs of colerainite crystals: 
A. Natural light 103 
B. Polarized light 103 
C. Polarized light 103 
Figure 1. Black Lake area 5 
2. Diamond 13 
3. Aragonite, simple crystal 25 
4. Aragonite, twin crystal 25 
5. Diopside, unusual habit, due to prominent development of the hemi- 
pyramid 2(331) 32 
6. Diopside, unusual habit, due to prominent development of the hemi- 
pyramid 2(331) 32 
7. Diopside showing new forms (front) 32 
8. “ « (back) 32 
9. * average habit. 33 
10. “ tabular habit 33 
11. “ flat termination (front) 34 
12. “ “ “ (back) 34 
13. “ twin crystal.,... 35 
14. Grossularite, rare six-faced octahedron u(853) 48 
15. tt exhibiting rare cube faces 49 
16. Montreal chrome pit 51 
17. Vesuvianite, lilac crystal, average habit, when m(110) is larger than 
a(100) 53 
18. Vesuvianite, lilac crystal, average habit, when a(100) is larger than 
m(110) 53 
19. Vesuvianite, lilac crystal, average habit, with striae 55 
20. “ emerald-green crystal 55 
21. “ average habit of pale yellow crystals 56 
22. “ average habit of emerald-green crystals 56 
