﻿1861.] 



KIRKBY PERMIAN, SOUTH YORKSHIRE. 



295 



Small-grained Dolomite in the third subdivision or " Great middle 

 deposit of Yellow Magnesian Limestone * " of Prof. Sedgwick. Some 

 of the most inferior appear to be placed in his second subdivision, 

 the " Marl-slate and thin-bedded and nearly compact limestone t". 



The organic remains of this subdivision possess considerable inter- 

 est, as our knowledge of the distribution of the Permian fauna in this 

 area is almost solely based upon them, there being but three species 

 of the Yorkshire list that range beyond its limits. The state of 

 preservation of the fossils is generally as casts, it being exceedingly 

 rare to meet with examples in a more perfect condition. Their 

 extreme abundance — at least of certain species — on some horizons has 

 been alluded to in the cases of Wentbridge and Brodsworth. And 

 so far as we may judge, this abundance extends over comparatively 

 wide regions ; for in the case of the Gervillia-bed, which occurs so 

 thick at "Wentbridge, I have traced it over a distance of twelve miles, 

 having seen it also at Pontefract (Bullhill Quarry), Emsall, Hooten 

 Pagnell, Brodsworth, Hickleton, and Barnborough Cliff. The polyzoan 

 beds I have not traced so far ; but they are to be found at Brodsworth 

 (Freestone Quarry), Hampole, and Cadeby. Further particulars of 

 the fossils of this member will be given in another part of the paper. 



As an approximation, 120 feet may be given as the probable thick- 

 ness of the Lower Limestone ; it being questionable whether it ever 

 exceeds that estimate, though scarcely so as to whether it sometimes 

 reaches it. 



Amongst other localities affording good opportunities for studying 

 its various beds, may be mentioned the numerous sections alluded to 

 in the neighbourhood of Pontefract, which illustrate the cellular and 

 arenaceous forms of it ; and the quarries at or near Brodsworth, 

 Hampole, Hampole Stubbs, Emsall, Conisborough, Cadeby, Moor- 

 house, Hooten Pagnell, and Hickleton the oolitic, polyzoan, and 

 compact beds. 



5. Rothliegendes or Lower Red Sandstone. — A deposit of yellow, 

 red, grey, or variegated sandstone ; fine-grained, or rather coarse in 

 texture ; of irregular structure, false-bedding being common ; and 

 though sufficiently firm to form a soft budding-stone in some locali- 

 ties (Pontefract, Barnborough Cliff, and "Wentbridge), yet often very 

 soft and incoherent (Wentbridge, Moorhouse, and Hickleton). 



The Lower Bed Sandstone of South Yorkshire differs little from 

 that of Durham, except, perhaps, in being a little more coherent and 

 finer-grained. And in no case have I observed any decided instance 

 of its unconformability to the overlying limestone, though it is not 

 always easy to say whether it is conformable or not, its stratification 

 being subject to such irregularities. There is no section on that 

 portion of the escarpment I examined that affords much support to 

 the opinion of those who would separate it from the Permian strata 

 on account of its unconformability to them — rather to the contrary. 



This deposit is so well described by Prof. Sedgwick that I woidd 

 rather direct attention to his remarks on it than attempt further 

 description. It is easy of examination along the escarpment in 



* Trans. Geol. Soc, 2nd ser.vol. iii. p. 81. t Loc. cit. p. 79. 



