734 



MR. J. SPENCER ON BOULDERS 



51. On Bouldees found in Seams o/Coal. 

 By John Spencer, Esq., F.G.S. (Kead June 23, 1887.) 



In working the coal-seams of Lancashire, particularly in those seams 

 found near the Gannister mine, from time to time isolated boulders 

 have been discovered, the position of which it is not easy to explain. 



These boulders are not always of the same kind. They generally 

 consist of granite, quartz, or quartzite, and probably of local rocks 

 which do not particularly attract the attention of the workmen in 

 the collieries. They vary in size from an inch to six or eight inches 

 in diameter, the largest being of granite. 



A fine specimen has lately been found at Old Meadows Pit, near 

 Bacup, Lancashire, by Mr. John Lord, Bacup. It weighs 6 lb. 

 The granite is composed of quartz, reddish felspar, and hornblende. 



This boulder was imbedded in the chief coal of the Itossendale 

 district, the Gannister or Mountain Mine, at a distance of 180 ft. 

 from the surface of the ground. Between this seam and the surface, 

 besides sandstones and shales, are found the Upper Foot or Bullion 

 Coal, the Forty Yards' Mine, and a small Cannel Coal, as seen in the 

 accompanying section ; — 



Surface 



Sandstones and shales . 



Cannel Coal, 1 in 



Sandstones and shales . 



Forty Yards' Mine, 



2 ft. 3 in. 



Sandstones and shales. 



Upper Foot or Bullion 1 

 Coal, 8-18 in. ...... j 



Sandstones and shales . 



Gannister Coal, 1 

 2 ft. 9 in. to 3 ft. J 



There was no trace of disturbance in the strata near where the 

 boulder was found. Similar boulders have been found at Crawshaw- 

 booth and Goodshaw Hill, about four miles from Burnley, at Wholaw 



