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L. On Gypsum near Doncaster, and Nodules of Limestone, 

 and of Pyrites containing Sea Shells, in the Coal district 

 near Bradford in Yorkshire. By a Correspondent. 



To Mr. Tilloch. 



Sir, JL/esirocs of contributing my inites towards the in- 

 teresting and important Geological investigations in which 

 your Correspondent Mr. John Farey is engaged, 1 beg the 

 favour of you to state for his information, and that of your 

 other Geological readers, that to the places where Gypsum 

 is found between the Yellow Lime Rocks, mentioned in 

 your present volume, page IO.t, that in line 7 from the 

 bottom may be added, after Edlington, " Marr 1^ m. S 

 (Gypsum quarries) ;" these Hall plaster Pits are situate 

 about ^ m. W of Cusworth, nearly W of Doncaster, in this 

 county. 



I beg also to mention, with reference to the 3d Coal- 

 shale of Mr. Farey's Report on Derbyshire, whose course or 

 basset edge, between the ad coarse Grit Rock, and the 4th 

 fine lamellar Grit or Pavine Rock, is briefly traced through 

 this county in your 102d page, that Mr. James Sowerby 

 in the last monthly number of his ■' British Mineralog}," 

 plate 455, has figured and described the nodules of pyrites 

 or brasses found immediately above the Coal, in Sir jfoseph 

 Banks's Colliery at Alton in Derbyshire, and again at 

 Whitley Wood in Sheffield Parish, that so remarkably 

 abound with the Ammonites Lis teri and Anomites resupivatus 

 of William Martin, and other shells; and mentions, that 

 nodules of black Limestone containing similar shells so 

 abound just above the Coal, near Cathrme Slack, 2 m. N 

 of Halifax, that a kiln is erected to burn them into Lime; 

 yet that specks of pyrites are seen in such Limestone Balls, 

 and some shelly balls, are all pyrites, found at that place, 

 but particularly so at other Collieries to the NE and E, as 

 the stratum ranges, E of Idle, near to Calverley, and Pars- 

 ley, across the Air to the S of llorsforth, &c. I very 

 much wish that your Readers and Correspondents in these 

 parts, would send you particulars of every like occurrence 

 of fossil shells in the Coal-measures, as being a very cu- 

 rious and important phsenomenon *, I am yours, &c. 



Yorkshire, 15th April 1812. F. O. E. 



* With regard to the question, p. 99, line 16, whether Red Marl is the 

 imiriediute upper st-atum to the Durham magnesian I.ime Rock, I would 

 mention, th::t I have heard, that at Hartlepool there is a Grit-stone Rock, in 

 very thin lamina, in some parts of it, and others take a good polish, perhaps 

 owing to a calcareous cement. 



LI. Geo- 



