228 TRANSACTIONS OF THE [mAR. 15, 



The Upper Coal Measv;res contain a few coal seams in their 

 lower half, the upper consisting of red shales and thin lime- 

 stones. 



The Lower Coal Measures. 



These Measures bound the northern side of the South Lan- 

 shirecoal field, and send thi'ee arras northwards through the Mill- 

 stone Grit countr}^ to the Burnley coal field, which they com- 

 pletely encircle. Immediately to the south of the latter coal field 

 the}^ cover a tract of country fifteen miles long from east to west 

 and three to five miles broad from north to south. 



The Lower Coal Measures include all tlie beds lying between 

 the Upper Rough Rock of the Millstone Grit Series and the 

 floor of the Arley Mine (also known as " Little Delf " at St. 

 Helens, " Riley Mine " at Bolton, and " Dogstone Mine " at 

 Bury). They consist mainly of shales, with thin bands of nodu- 

 lar ironstone, sandstones, and thin coals, reaching in all a thick- 

 ness of 1,200 feet along the line of the " Rossendale Anticlinal." 

 Not more than six coal seams are present in the series, the total 

 thickness rarely exceeding ten feet. 



The accompanying generalized section in the Rossendale area 

 serves to illustrate the position and thickness of the seams. 



Ft. In. 



Strata ? 431 



Upper Mountain Mine Coal 1 6 



Strata 36 



Coal 2 



Strata 56 



Upper Foot Mine Coal 8] Five Feet 



Strata 30 }■ Mine where 



Gannister Mine Coal 2 6J they unite. 



Strata 20 



Lower Foot Mine Coal 8 



Strata 40 



Bassey or Salts Mine Coal 23 



Strata 100 



Coal 10 



Eough Rock 



The coal seams are frequently termed " Mountain Mines," 

 owing to their general occurrence in the high ground. But three 

 are of commercial importance, viz. : The " Gannister," " Yard " 

 or " Lower Mountain Mine ; " the " Upper Foot " or " Bullion 

 Mine," and the " Upper Mountain Mine." The " Bassey," or 

 " Salts Mine," is a very impure coal and not much used. It is 

 worked to some extent in the Blackburn area. The Upper 



