76 Prof. Sedgwick on the Carboniferous Chain 



tensively worked in the Barbon and Casterton liberties, where it is about 

 fourteen inches thick. The lower part of this bed is however so impure, as 

 to be unfit for domestic use, and is chiefly consumed in lime-works*. An 

 attempt is now making to work the same bed in the adjoining liberty of Dentf . 

 It is also worked at Stoth pits nearHawes, in Baw Fell above Sedbergh, and 

 at Kitchen Gill on the side of Naitby Pell near Kirkby Stephen ; and there 

 are many traces of old works in the same bed near Garsdale Head^. I am 

 certain that in all these places the coal is very nearly on the same geological 

 parallel. It must therefore have been very widely extended. But it was by 

 no means continuous, as is proved by innumerable sections through this group, 

 which perpetually varies in its composition, and in which there is often no 

 indication whatsoever of the coal-bed. It deserves remark that the two thin 

 calliard beds appear to be continuous for many miles. 



The slate-beds in division (c.) are next in importance. They have been 

 extensively worked in several places ; especially at Wydern and Kirkbank in 

 the valley of Dent : but the most beautiful example of these beds is in Cow 

 Gill, about five miles above the village, where there is a quarry of hard, white, 

 siliceous grit capable of being split into very thin flags, coated with silvery 

 mica, and forming the most beautiful roofing slate I have seen in the carboni- 

 ferous chain. 



7. Mosdale Moor or Wold Limestone^. Average thickness from 30 to 40 

 feet. 



* Section, in descending order, from the shaft of the Barbon coal-pits : — 



Feet. Inch. 



5. Alternations ofgritstone and shale 12 



6. Shale 30 



7. Crow-limestone 2 



8. Plate, with a three-inch crow-coal 1 6 



9. Gritstone 27 



10. Coal 1 2 



Feet. Inch. 



1. Alluvial soil, &c 52 6 



2. Plate (calcareous shale) 1 6 



3. Limestone (the fourth, or Mosdale 

 Moor limestone, of the general 

 section) 27 



4. Gritstone 27 



The crow-limestone (No. 7.) more commonly appears in the form of two distinct bands sepa- 

 rated by a bed of impure, pyritous shale. In this section, the beds seem to have run together ; 

 probably by the partial disappearance, or thinning out of the pyritous shale. 



t The attempt was unsuccessful, and the works have been deserted since the above passage was 

 written. 



J I have been informed that the coal of Kitchen Gill is eighteen inches thick ; but I have seen 

 no accurate sections of the works. In the places where it has been most worked the average 

 thickness of the bed is not much more than a foot. 



§ The group is known in some of the valleys under the name of Wold-limestone: as, however, 

 this word designates any tract of dry green pasture land rising out of the morasses of the carboni- 

 ferous chain ; and as this kind of soil marks, more or less, the range of all the calcareous groups ; 

 the term wold is a bad distinctive name for any one of them. 



