No. 7.] DAWSON — COAL SEAMS. 425 



At the mouth of the St. Mm-}' the main seum has a thickness 

 of three feet six inches, but about eighteen inches at the top is 

 rather shaly. 



On comparing these sections on the St. Mary with those at 

 Coal Banks and on the Belly River to the north, it will be noticed 

 that the coal at the first-mentioned locality is more divided by 

 shales and less favourably situated for working. 



On the part of the Belly River near Coal Banks the measures 

 have, as a whole, a light westerly dip, while that part of the out- 

 crop between Coal Banks and Big Island forms a minor synclinal 

 hollow in its edo-e, across which the river cutis in a direction 

 nearly coinciding with the main strike of the measures, and gives 

 rise to a great display of coal on this part of the valley. The 

 cotl-bearing horizon, as above mentioned, lies at the base of the 

 Pierre, and its position between the dark shales of this formation 

 and the pale sandy beds of that underlying it, renders it easy to 

 define the situation of the coals, even where their actual outcrop 

 is concealed. For a distance of five miles north of the Coal 

 Banks exposures, the dark shales just referred to occupy the 

 river valley, while the outcrop of the coal is carried eastward to 

 an uncertain distance by the light synclinal undulation above 

 referred to. The gentle inclination of the measures shows that 

 the coal might be reached at a moderate depth by shafts sunk 

 through the dark shales in this part of the valley, from whicb 

 it might with facility be worked up its slope to the eastward. 

 The undulating character of the dips renders it impossible to 

 e^timate the exact depth at which the seam would be found, 

 but it is probably not over 500 feet below the river, midway 

 between its southern and northern outcrops in the valley. It 

 may also be worked on a smaller scale, but with great facility, 

 by levels driven into the actual outcrops in the river banks. 



Having thus briefly described the general mode of occurrence 

 of the coal on this part of the Belly River, the following more 

 detailed notes on the outcrops which occur will serve to show 

 the actual character of the seam. 



At the Coal Banks, the coal has been extracted chiefly by 

 quarrying along the natural outcrop, though during the past sum- 

 mer a small level has been begun. The outcrop is situated in 

 the front of a steep scarped bank facing the river, and the seam, 

 which at the southern end of the bank is about 30 feet above 

 the water, dips away below the water at the northern. The fol- 



VOL.. X BB No. 7. 



