in the Vicinity oj Manchester. 245 



bivalve shells occur, one of which, I believe, is Crassina, but as 

 they are only casts, the species cannot easily be determined. 

 The most important fossil is the Axinus, as from its extreme 

 abundance in the magnesian limestone of Yorkshire it formed 

 a ready means of identification. 



From this it will be seen that the magnesian limestone of 

 the neighbourhood of Manchester is an unimportant bed com- 

 pared with that of many other districts. The German zech- 

 stein and kupferschiefer have their remains of the Monitor and 

 Palaeothrissum, together with the peculiar impressions of Fii- 

 coids. The limestones of Durham and Northumberland have 

 their Zoophyta and Radiaria, with numerous Mollusca and 

 remains offish. In Yorkshire are thick ranges of a yellow 

 lamellar limestone, so well exhibited on the line of the Leeds 

 and Selby Railway, literally teeming with beautiful specimens 

 of Axinus ; and here we have only a few unimportant beds of 

 limestone, almost lost amongst the clays in which they occur, 

 and only exhibiting a few casts of fossils, of which but one or 

 two (the specific characters of which are so striking as not to 

 be mistaken,) can be distinctly recognised. 



We will now examine the series of limestones, which as a 

 means of local distinction we have called the 



(Sect. IV.) Ardwick Limestones. 



This provincial name has been given to the series of strata 

 from the pits where they are chiefly worked being situated 

 near the township of Ard wick. In this neighbourhood they 

 are only exposed at the surface in the bed of the river Med- 

 lock, near Ancoats, but on the elevated ground above the river 

 they are worked in several pits on a similar plan to the col- 

 lieries. These are now the property of — Brocklehurst, Esq., 

 and are under the management of Mr. F. Mellor, whose prac- 

 tical information and readiness to afford us every opportunity 

 of examining the sections exposed in the different pits have 

 been of the greatest importance to us. 



The following is an average section of the general appear- 

 ances of the strata at the above pits, in a descending order : 



Ft. In. 



Limestone 4 



Coloured red and blue clay, by the miners called " cluncli" 6 



Coarse micaceous grit 6 



"Clunch" 6 



" Roofstone," a shaly sandstone 3 



Limestone " ^ 



Clunch 5 



Limestone ~ " 



