664 ON THE CASCADE ANTHRACTTTC COAL-FIELD. 



As the mountains are approached they influence the quality of 

 the Coal very materially. From a number of specimens collected from 

 outcrops by members of the Greological Survey, Dr. George M. Dawson 

 and Mr. Hoffman suggest three horizons *, represented by districts 

 at varying distances from the mountains or in the mountains. 



1. In the prairie to the east, the true Lignites occur, the 

 hygroscopic v^ater ranging from 6 per cent, to 21 per cent., and the 

 fixed carbon varying from 41 per cent, to 55 per cent. They 

 continue to a line about 15 miles from the mountains. Throughout 

 the area to the east of this 15-mile line the rocks are practically 

 horizontal, and for about 100 miles to the east from this line the 

 hygroscopic water is found to increase in a more or less regular 

 ratio of about 1 per cent, for each 10 miles. At the 15-mile line 

 the water- contents of the lignite are put at 5 per cent. Dr. Dawson 

 hesitates to make the influence of pressure wholly responsible for a 

 variation found to extend throughout horizontal beds for more than 

 100 miles ; and as he computes from known variation in the coals 

 that there is about 2 per cent, change in hygroscopic water for 

 every 1000 feet of strata, he thinks a varying thickness of overlying 

 or shore-beds on the mountain coast-line may have been washed 

 away. 



2. Between the eastern edge of the mountain (Palaeozoic) forma- 

 tion, which is well defined and straight, and the above-mentioned 

 15-mile line to the east, the foot-hills show evidence of much 

 disturbance and pressure. 



"Within this area the quality of the lignites approaches that of 

 true coal, the hygroscopic water in them ranging from 1*63 to 6*12 

 per cent, and the fixed carbon from 50 to 63 per cent. 



3. The anthracite or semi-anthracite, occurring in the Cretaceous 

 and Laramie deposits which have been caught up in the Palaeozoic 

 rocks of the mountains, is found in long troughs lying in the 

 mountains. 



The general section that accompanies this paper shows one of 

 these troughs, and in this case the accompanying coal has been 

 altered into an anthracite, and is, I believe, the only case yet known 

 in Canadian territory where the metamorphic influence has been 

 carried so far in the coals occurring in the above-mentioned 

 formations. 



* Eeport of Progress of Geological Survey of Canada, 1882-84. 



