ii7 



obtained. The fibre appears to He chiefly along the 

 slipping planes, which are the result of the shattering of the 

 rock into innumerable small pieces by some such cause as 

 swelling during serpentinization, general regional meta- 

 morphism, or folding. The rock is much more completely 

 altered than that of the Thetford deposits and now consists 

 almost entirely of serpentine with a certain amount of talc 

 — the latter indicating the impure nature of the original 

 peridotite. 



Sills. 



In striking contrast to the deposits at Thetford and 

 Black Lake, which are in the margin of a stock several 

 miles across, the asbestos deposits at East Broughton 

 occur in sill-like bodies. Two pits have been opened to 

 the full width of a sill about ioo feet (30 m.) thick of which 

 both the foot and hanging walls are exposed. Other smaller 

 parallel sills also occur close at hand. The main sill extends 

 nearly continuously for 6 miles (9-6 km.), five pits having 

 been opened up in this distance. It is also probable that 

 the pits of the Berlin, B. & A., and the Robertson Asbestos 

 Co., 8 miles (12-8 km.) farther on, are in the same sill, so 

 that the sill has a probable length of about 14 miles (22-5 

 km.). 



BIBLIOGRAPHY. 



1. Logan, Sir William. . .Geol. Surv. Can. 



Geol. of Canada, 1863. 



2. Adams, F. D Geol. Surv. Can. 



Rept. of Progress 1 880-1-2. 



3. Ellis, R. W Geol. Surv. Can. 



Vol. II. Part J., 1886. 



4 Geol. Surv. Can. 



Vol. III., Part K., 1887-8. 



5. Geol. Surv. Can. 



Vol. IV., Part K., 1888-9. 



6. Cirkel, Fritz Chrysotile-Asbestos. Dept. 



of Mines. Mines Branch, 



Pub. No. 11. 1905. 

 7 Chromite. Dept. of Mines. 



Mines Branch, Pub. No, 



29. 1909. 



8. Dresser, J. A Geol. Surv. Can. 



Summary Repts. 1907-09-10. 



