46 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 3, 



true laminae of deposit*. In the Thornton section, the upper part 

 of this group (just where it sinks under the dislocated beds of the 

 great Scar-limestone) passes into a mass of dolomitic limestone mixed 

 with shale and flagstone. It contains a few Encrinite-stems, obscure 

 Corals, and Shells of which the species could not be determined. 

 But, passing over to the other section below the Ingleton slate-quarries, 

 we find the same group, which is more widely expanded, probably 

 in consequence of the transverse and unconformable position of the 

 overlying Scar-limestone. The whole length of the group is not, 

 however, more than a few hundred feet; and it is intersected by 

 two dykes, chiefly composed of red felspar and black mica, which, if 

 I mistake not, run together in the higher part of the neighbouring 

 hill f. The whole group is, like that of the other section, more or 

 less calcareous ; and the calcareous matter is arranged in a similar 

 manner ; but no part of it passes, in mass, into what might be called 

 a dolomitic limestone. The most calcareous portions are near the 

 upper dyke ; and from these (helped by the practised hand of my 

 friend John Ruthven) I obtained, at length, a number of very obscure 

 fossils, and among the fossils a few species which seemed to belong 

 to the series of the Coniston limestone. They have since my re- 

 turn been examined by Professor M*Coy, who identifies the following 

 species ; — 



Stenopora fibrosa, Goldf. sp. (ranging from the Bala to the Lower 



Carboniferous rocks). 

 Halysites catenulatus. Martini, sp. (ranging from the Bala to the 



Ludlow rocks) . 

 Orthis Actonise, Sotv. ; and one or two other ill-defined species of 



Bivalves. 



There are, in the great cluster of the Cumbrian mountains, no 

 groups, either above or below that of the Coniston limestone, with a 

 group of fossils like those above-named. This fossil evidence, im- 

 perfect though it be, is confirmed by the mineral structure of the 

 neighbouring rocks; and hence we may, I think, safely conclude, 

 that the group here described (from the Ingleton and Thornton 

 sections) is the true equivalent of the Coniston limestone. The 

 overlying beds of the great Scar-limestone, followed by the carboni- 

 ferous grits, &c., which descend towards the Black Burton coal-field, 

 require no further notice in this place. 



Section from the top of Penygent to Settle, on a line nearly par- 

 allel to the Valley of the Ribble. Fig. 5. — Were I describing a new 

 country, it would be necessary for me, in this place, to give a map of 

 the singular denudation of the slate-rocks in the valley of the Ribble 

 (above Settle), as well as in some lateral valleys connected with it. 



* A most remarkable instance of this structure is seen at the S.W. end of the 

 Coniston limestone after it has passed into Cumberland. One quarry shows a 

 series of calcareous spherical concretions arranged on the planes of cleavage, and 

 not on the true planes of bedding. 



t The structure here noticed is seen in several other dykes near the line of the 

 Craven fault. 



