GEOLOGY. 21 



Lovely Seat 535 feet and on the north side 662 feet ; and at 

 Leyburn a coal seam upwards of a foot thick is obtained on the 

 moor top about 120 feet above the Main Limestone, which has 

 a thick gritstone over it on the east, and in the neighbourhood 

 of Downholme and Hudswell the same coal seam is also 

 worked. 



Next we pass to the tract of the great synclinal depression, 

 and by combining two of the Arkengarthdale mining sections, 

 and taking for each bed its greatest thickness in either of the 

 two we obtain the following result, viz. : — 



feet. 



jr /Main chert 18 



°" ^" \ Alternations of plate, limestone & chert 80 



No. 3. White gritstone > 66 



, Grit and plate with coal 25 



I Crow limestone i8 



No. 2. -| Flinty chert with alternations of plate ... 51 



I Alternations of plate and limestone 37 



Opiate 30 



No. I. Millstone grit 120 



Total 445 feet. 

 Here the top Millstone Grit would appear to represent the 

 Middle Grit of Nidderdale and the Summit Grit of Penhill and 

 the Colsterdale watershed, and the White Grit the Lower Gritstone 

 of Nidderdale and Ingleborough, the rest of the beds being 

 grouped and numbered in correspondence with the Nidderdale 

 section on page 19. 



On the Stonesdale side of Water Crag the series is upwards 

 of 900 feet thick, and here we have above the Main Limestone 

 122 feet of the Lower Cherty group, 80 feet of the White Grit, 

 no of the Upper Cherty group, and 600 feet more of Plates, 

 Middle Grits and the Upper Plates and Grits of Nidderdale before 

 we reach the summit. In Nine Standards the Main Limestone 

 is considerably higher than in Water Crag, and the Gritstone 

 thinner. At this point it is about 400 feet in thickness, and 

 from thence along the summit of the escarpment over Maller- 

 stang as far north as Stainmoor, the upper beds are still those 

 which overlie the upper Arkengarthdale Grit. At the western 



Feb. iSSS. 



