Yol. 6S.^ succESSioisr in the north-west of England. 497 



to PteridorlmcJiis sp.^ Above the j)lant-shales occurs a yellow 

 cellular dolomite containing drusy cavities. This is the highest 

 bed in the series exposed in the bed of the stream, but it has yielded 

 no determinable fossils. The total thickness seen is about 65 feet, 

 and the beds are dipping at 17° north-north-eastwards, or about 

 the same average dip as that of the overlying Lower Carboniferous 

 rocks in the district.^ 



About 8 yards below the road-bridge is a small outcrop of 

 thinly-bedded, red, shaly conglomerate, which contains pebbles 

 ranging up to 2 inches in diameter and composed of Silurian 

 grits and rhyolites ; also scattered through the deposit are pink 

 orthoclase-crystals, similar to those commonly found in the con- 

 glomerate at Shap Wells, and there can be little doubt that 

 this deposit is the southerly continuation of the Shap Easement 

 Conglomerate. The beds in Pinskey Gill, described above, are 

 therefore o£ peculiar interest, since they apparently underlie the 

 Shap Conglomerate which forms the usual base of the Carboni- 

 ferous in the Shap District, and must therefore represent the 

 oldest fossiliferous horizon in the Carboniferous rocks of the 

 North -Western Province. The beds were evidently deposited in 

 a depression which was invaded by the Carboniferous sea before 

 the general submergence of the districts lying immediately to the 

 north and south, and apparently prior also to the submergence 

 of the Shap Granite. How much earlier it is impossible to say, 

 by comparison with any beds in the jSTorth of England — since the 

 nearest exposures of Carboniferous rocks, which may possibly re- 

 present their equivalents in time, are not met with until we reach 

 the extreme north of Cumberland; and my recent investigation of 

 the beds in this district has revealed no fauna at all similar to 

 that recorded from Pinskey Gill. Again, if these beds are of Car- 

 boniferous age, it should be possible to correlate them with some 

 definite horizon in the Lower Carboniferous succession of the South- 

 western Province, but such a correlation is by no means easy. 



If we are to consider the Pinskey Beds as conformably succeeded 

 by the conglomerate which crops out below the bridge, and by the 

 fossiliferous series exposed in Stone Gill hard by, they should repre- 

 sent some portion of the Zaplirentis Zone of the Bristol district ; 

 but Dr. Yaughan, who has kindly examined my collections, and 

 also specimens collected by Mr. Cosmo Johns from this district, 

 reports that the characteristic Spirifer of the Pinskey Beds is quite 

 unknown to him from the Carboniferous rocks of the Bristol area, 

 while none of the other fossils appear to throw any further light 

 on the problem. 



Considered on strati graphical grounds alone, these beds may be 

 of any age between the date of the post-Silurian movement in the 

 district, and the deposition of the lowest beds of the Solenopora 

 Sub-zone : that is to say, there is apparently nothing in the strati- 



1 Teste Prof. A. C. Seward, F.E.S. 



2 A detailed section of these beds is given in ' The Geology of the Country 

 around Mallerstang, &c.' Mem. Geol. Surv. 1891, p. 79. 



Q. J. G. S. No. 272. 2 



