from Penigent to Klrkby Stephen. 77 



This limestone is less regularly bedded than the two preceding groups 

 (Nos. 3. and 5.). The bottom beds are generally of a grey colour and of an 

 open, shaken texture. They are frequently surmounted by two or three 

 coarse, strong beds of a grey colour, not to be mineralogically distinguished 

 from the most ordinary varieties of the great scar limestone, containing 

 various fossils, apparently distributed without regularity. The higher beds 

 become thinner, more compact, and sometimes contain many encrinital stems, 

 and are occasionally of a dark colour. In the highest part of the series, the 

 beds alternate with bands of dark shale, become impure and ferruginous, and 

 frequently pass into the state of crow-limestone or calliard, with many large 

 Productae. 



Detailed sections of this division would, no doubt, offer many modifications; 

 but few quarries have been opened in it, since it contains no beds of any pe- 

 culiar value, and many parts of it are obscured by alluvial accumulations. It 

 may, however, be tracked without any difficulty, wherever it rises to the day, 

 along the sides of all the mountains which range near the lines of section ; 

 as well as in all the various systems of valleys which branch among the moun- 

 tains between Askrigg and Kirkby Stephen. It has indeed been important to 

 make out its continuity, as it forms the roof of a series of beds to which the 

 Barbon coal seam is subordinate (No. 6. (6.)) 



8. Alternations of Sandstone, Fissile Gritstone, and Shale. This is by 

 much the most remarkable of all the groups alternating with the beds of lime- 

 stone. Its greatest thickness is perhaps as much as 350 feet; and its 

 average thickness in the central and southern parts of the section is about 

 200 feet. 



Like all the other masses composed of sandstone and shale, it is extremely 

 variable in its structure, the subordinate parts either disappearing or replacing 

 each other. In some places the alternations are indefinite: but on the whole 

 it admits of the following approximate subdivisions. 



(a.) Alternations of slaty, micaceous gritstone and shale, som.etimes con- 

 taining bands of crow-limestone. 



(b.) Shale with bands of gritstone. 



(c.) Micaceous, fissile gritstone with thin bands of shale, and with subordi- 

 nate masses of coarse gritstone. 



There are very fine quarries in the lower division («.), especially at Raw- 

 thay Gill (between Ravenstone Dale and Sedbergh), where in colour the 

 gritstone somewhat resembles the Pennant stone of Bristol; but is more 

 micaceous and fissile, and generally of a more open grain. In the higher 

 part of the upper division (c), the fissile beds have been extensively worked 



