from Penigent to Kirkhy Stephen. 79 



analog^y by help of which we compare them with the cherty beds in i\\e four- 

 fathom limestone of the mining districts of Swaledale and Arkendale. 



The strongest masses of this group (in which the fossils are all more or less 

 white and crystalline, and imbedded in a dull grey, nearly compact limestone), 

 are, on the north side of Garsdale, extensively quarried for the Kendal marble 

 works ; and works were opened on the corresponding strata in the valley of 

 Dent, but are now deserted ; a better material having been there discovered 

 in the twelve fathom limestone. 



10. Gritstone, Coal, and Shale. Thickness varying from 50 to 80 feet. 

 The prevailing order appears to be nearly as follows : 



(a.) Thin-bedded gritstone, sometimes coarse-grained. 



(b.) Coal and carbonaceous shale. 



(c.) Bands of light-coloured, micaceous grit. 



The lowest division (a.) is of very variable structure. It is in some places 

 very coarse-grained ; but in Uldale, between Swath Pell and Baw Fell, it 

 passes into a dark, compact, siliceous mass, exactly like the metalliferous chert 

 of Swaledale. Along the line of section this cherty form is, however, an ex- 

 ception to the prevailing structure. The coal varies in thickness from a mere 

 trace to two feet, and is in many places of excellent quality*. When it reaches 

 its maximum thickness, it is, however, generally mixed with shale and other 

 impurities. To the north of Ingleborough, no member of the whole series is 

 more continuous than this coal-bed and its superincumbent shale ; and it has 

 been worked, more or less, in almost every mountain near the lines of section. 

 But in Ingleborough and Penigent the whole group here described thins out 

 to such a degree, that the four fathom and twelve fathom limestones become 

 confounded, and present a single unbroken escarpment. To the north of the 

 line of section the same coal is now extensively worked in the neighbourhood 

 of Brough. 



11. Twelve fathom Limestone. This system of beds makes a striking fea- 

 ture in many parts of the carboniferous chain of the North, being the highest 

 limestone group of sufficient thickness to give any character to the soil or to 

 produce a distinct escarpment. In some districts it forms the crown of a long 



* This coal was formerly worked to a considerable extent, by means of horizontal drifts, under 

 Great Colm, on the south side of the valley of Dent, though not more than five or six inches in 

 thickness. It was of excellent quality, and in such request, that about seventy or eighty years 

 since, it was sent on pack-horses over the mountains as far as Kendal for the use of the black- 

 smiths' forges, &c. I know of no fact which places in a more striking point of view the great im- 

 provements in internal communication within the period above mentioned, A supply like this 

 would now be utterly worthless. The extensive manufactories of Kendal have long been supplied 

 with fuel from the great Lancashire coal-fields. 



