274 Cosmo Johns : Lower Carboniferous Rocks of Mill Gill. 



sulcatus occur. Their occurrence so near the level of Posido- 

 nomya becheri is significant. 



The Hardraw, Simonstone and Middle Limestones are well 

 exposed, but a discussion of their fauna can hardly be under- 

 taken here. The Underset and Main Limestones which are 

 exposed in the well-known Whitfield Scars, have yielded an 

 important fauna, including Productus giganteiis and Prod, 

 latissimus. These forms are abundant at many levels from 

 the base of the Yoredales to the Main Limestone, and are only 

 mentioned to emphasise their range throughout the Yoredales. 

 It is the coral fauna which is of present importance : — 



Lithostrotion irregulare (small var). 

 Cyclophylluni packyeiidotheciim (adv. mut.). 

 Dibunophyllum murheadi. 

 ,, splendens. 



Lonsdalia cf. dtiplicata. 



A larger list could be given if forms obtained from the 

 Main Limestone of the neighbouring dales were included. 

 This fauna has enabled a definite correlation of the Main 

 Limestone of the Yoredale area and the Great Limestone of 

 North Northumberland, to be made, and a valuable confirmation 

 of the stratigraphical evidence is thus obtained. 



A Digression. 



At this point it might serve some useful purpose if certain 

 conclusions as to correlation of the Yoredale Series be briefly 

 stated here, while reserving a fuller discussion of the evidence on 

 which these conclusions are based for another communication. 

 The Main and Upper Scar Limestone of Ingleboro', Penyghent, 

 Buckden Pike and of the ridge that divides Wensleydale from 

 Swaledale, contains the same brachiopod and coral fauna as the 

 Great Limestone of Weardale and North Northumberland. 

 This Main or Upper Scar Limestone is the highest calcareous 

 member of the Yoredale Series in the country between the 

 Craven Faults and Wensleydale, and is succeeded, after an 

 interval of a variable thickness of shales and sandstone, by the 

 Ingleborough Grit. This Main Limestone of Ingleborough can 

 be correlated with confidence with the Crinoidal Limestone of 

 Whittington which occupies the same relative position to the 

 Millstone Grit above, and the Limestone masses below. This 

 was also the opinion of Phillips, and indeed no other conclusion 



Naturalist, 



