284 GILPIN ON THE GROUPING OF THE PICTOIJ COAL SEAMS. 



found 80ft. beneath the McBean, adds to the probability that the 

 8 ft. seam of New Glasgow is identical with the McBean. 



Turning again to the main seam we find it overlaid by 1130 

 feet of barren shales, succeeded by a small seam of coal, still as- 

 cending beds of sandstone alternate with the shale, and among them 

 two or three small seams of coal, one of which before alluded to 

 agrees in thickness with the Stewart seam believed to underlie the 

 Richardson ; should this be the case we can form an approximate 

 idea of the thickness of the productive measures. 



Lying unconformably against the southern crops of the Marsh 

 and McBean seams are two groups known as the McLennan and 

 McLean. The latter contains four beds of coal with an aojorreo^ate 

 thickness of 25 feet. Little has been done to prove the position 

 and thickness of the seams belonging to the former group, the two 

 lower seams are each 4 feet thick and lie about 1650 feet above the 

 McLean group, thus closely agreeing with the estimated section 

 between the main seam and the supposed equivalent of the Stewart 

 seam. Should these prove the equivalents of the Albion seams, we 

 should find the crops of the Main seam beneath those of the McBean, 

 and the continuity of the group established across the Basin. 



There are 1130 feet of barren shale above the Main seam, and 

 at least 400 between this point and the seam before mentioned. 

 Crossing to the Stewart seam we find that its strike would carry it 

 500 yards to the rise of the East River seam, which, together with 

 its pitch, would make the thickness of the intermediate strata 750 

 feet. We have thus the following table : 



Main seam to Stewart seam 1530 feet. 



E. River seam 750 «' 



Marsh Group 800 '' 



Contained in Marsh Group 170 '' 



Above Marsh Group 1740 '« 



4990 feet. 



Which would give the productive measures a thickness of at least 

 5000 feet. 



The identity of the Widow McLean seams with those of the 



