﻿1861.] 



KIRKBY PERMIAN, SOUTH YORKSHIRE. 



313 



is the common fossil of the locality, is only one-fourth its usual size. 

 The molluscan remains are mixed with comminuted Polyzoa, chiefly 

 of the species Acan. anceps, the fragments being very small, though 

 numerous. As it happens, however, the reduction in size of the 

 fossils is accompanied by an improvement in their state of preserva- 

 tion, and particularly in respect to the Univalves, which are generally 

 testiferous. So numerous are these minute fossils in some parts of the 

 quarry, that the quantity of them that occur in a small portion of 

 matrix is most surprising, a fact rendered easy of proof by the 

 friable nature of the matrix. As illustrative of this, I may mention 

 that in but a quarter of an ounce of limestone I have picked out 

 298 separate organisms, the majority being specimens of Turbo heli- 

 cinus. Another experiment of a like kind, the quantity of limestone 

 being the same, yielded even more astonishing results. From it I 

 extracted 461 specimens of T. helicinus, 18 of Turrit. Altenburgensis, 

 7 of Pis. Leighi, 2 of Terebrat. elongata, 1 of Bairdia plebeia, 24 of 

 Miliola pusilla, and 8 fragments of Stenopora Mackrothi ; in all 513 

 organisms. A cubic foot of this limestone of equal richness as the 

 latter throughout, and supposing it to weigh 120 lbs. (a low estimate), 

 would contain very nearly 4,000,000 of distinct individuals — 

 and these not truly microscopic, but distinguishable with the naked 

 eye, most of them being Gasteropodous Mollusea. All the limestone 

 of this locality, however, is not so highly fossiliferous as in these 

 examples, there apparently being certain zones of limestone that are 

 pre-eminently fossiliferous. Besides illustrating the extreme abun- 

 dance of these minute fossils, the above facts give a good idea of the 

 relative abundance of individuals belonging to the different species. 

 They show that Turbo helicinus is by far the most common form, and 

 that its individuals outnumber many times over the aggregate of those 

 of all the other species. And this is the only instance I have met with 

 where the Gasteropod in question, though very generally distributed 

 in the Lower Limestone, has taken the leading place among the fossils 

 of a locality. And, besides, this is the only locality in Yorkshire — per- 

 haps in England — where Gasteropoda hold so important a position in 

 the list of species, about half of the3Iollusca being species of this class. 



Near Brodsworih. — Another interesting locality is near to Brods- 

 worth in some old quarries just to the west of the village, where the 

 beds belong to the higher part of the Lower Limestone. The pre- 

 dominating fossil here is Gervillia antiqua, its casts composing almost 

 the whole of the substance of some of the beds. This species is just 

 as common here as Axinus dubius is at Moorhouse, or Turbo helicinus 

 at Hampole. And the beds in which it is so plentiful are probably 

 identical with those at Wentbridge, Pontefract, etc., where we have 

 noticed it as occurring in similar profusion. Along with the Gervil- 

 lice are to be found the remains of a few other species, amongst which 

 (rarely) are those of Nautilus Freieslebeni and Chiton Loftusianus. 



Near Pickbum. — Between Pickburn and Marr there is a quarry 

 called by the villagers the "Freestone Quarry* " — of thick-bedded 



* In the south of Yorkshire any stone that can be easily worked by the mason 

 is termed a "freestone." In Durham this term is only applied to sandstones. 



