THE CARBONIFEROUS SYSTKM 301 



l, ami some of these are so full of Carbonicola shells that 

 thrv are known as "mussel bands." The sandstones are used for 

 liuiMing purposes, and one bed, known locally as the "grindstone 

 P"-t," furnishes the celebrated Newcastle grindstones. No true 

 lp per Coal-measures come into this area, though they may exist 

 under the North Sea. 



The Cumberland or Whitehaven coalfield borders the western 

 coast from Whitehaven to Maryport and then runs north-eastward 

 in a narrow tract which is faulted down between the Permian Beds 

 and the Carboniferous limestones. The whole area, indeed, is so 

 broken by faults that the thickness of the Coal-measures is not 

 known, but believed to be over 1500 feet Lithologically the series 

 is divisible into (1) Productive Measures and (2) the Whitehaven 

 Sandstone ; but from an examination of the plant remains Mr. Arber 



groups the beds in the following manner : 



Feet. 



Whitehaven / Upper division = Transition Beds . 418 

 Sandstone \ Lower division) f200 



g 



Productive / Upper division/ . 1450 



Measures \ Lower division = Lower C.M. . ? 800 



Both divisions of the Whitehaven Sandstone consist of purple 

 sandstones, shales, and conglomerates, which weather to reddish 

 tints, and the upper division includes a bed of Spirorbis limestone. 



The Canonbie basin though small is interesting because it is 

 deep enough to bring in still higher beds, and because the strata 

 resemble the English Series more than the Scotch Coal-measures. 

 The following abstract is taken from the full account given by 

 Messrs. Peach and Home : 



Feet. 



TT /Red and purple sandstones and shales with a Spir-} ^QQ 

 Upper-^ whig limestone and 2 seams of ironstone . / 



Middle White sandstones, grey shales and coals . . . 500 



Lower Grey sandstones, shales and coals .... 750 



. f Massive sandstones, some coarse, with shales and"\ ,, n 

 M. Grit | thin coal . seams ...... / 



3400 

 3. Scotland 



The Westphalian Series is not so fully developed in Scotland 

 as it is in Central England, but it is curiously different from that 

 of Northumberland, for the Lower Coal-measures are of considerable 

 thickness, while the Middle Division, which is the most productive 

 part of the English Series, has a very different facies in Scotland, 

 its beds being often called the " barren " measures because they 

 contain no coal-seams. There are four separate coalfields occurring 



