162 Coal-Jklds of Derhy. and North tPales, compared. 



or soft and perishable stone, and making two distinct Basset 

 Ridges, such, that had I happened in 1807, to have begun my 

 Survey here, instead of near i\shovcr, these divided Rocks, mu^t 

 each have had separate names or numerical designations. 



The positions which I at first adopted from Mr. Whitehurst 

 (on reviewing nearly the sa77ie local facts as he had observed) 

 as to the orily very course gritstone of this series, occurring ii* 

 the 1st Rock, and that "Coals are never found under coarse 

 Gritstone," I in part corrected in 1S09, by the discovery (first 

 niadt near this border of It'orkshire) of the coarseness of the 

 ^rd Rock, in numerous situations : but these now appeared, 

 .still further to be untenable positions, since in this corner of 

 \ orkshire, the 2d Grit Rock was not only found very coarse 

 in some places (and very fine and perfect, with concentric stains 

 like "hale-gritstone, in others), but the Car-hoii.se Rock* in the 

 ord Coal-shale, which in many places in Derbyshire appeared 

 only as a very imperfect Stone or Bind, and even in a greater 

 numljer of situations could ?int be di^/inguished (and therefore 

 had not been numbered in my Series), here proved very coarse 

 and tiiick, and formed the most conspicuous rocky Edges in the 

 district ! And, what v\'ill perhaps prove of greater interest to 

 your Geological Readers, the 1st Coal-shale, not only produces 

 here very coarse grit-stone beds, or large lenticular masses of such, 

 and others that contain much calcareous matter, but it begins also 

 to assume here, those metalliferous characters which have so long 

 puzzled, in comparing the mining district of Yorkshire, Dur- 

 ham, and Northumberland, with that of Derbyshire; the Broom- 

 head and Wigtwizle Mines of Bleude and Galena, proving to be 

 in rake veins in the \st Coal-shale ! 



On examining the Coal-field of Anglesea Island 16 months 

 ago, the appearances were so very dissimilar from the above, in 

 the nearness of the workable seams of Coal to the Limestone, in 

 the inconsiderable tliickness of these calcareous Rocks, before 

 coarse Slate commenced under them ; leaving scarcely any space 

 for the Toadstones, tlie Limestone-shale, or the 1st, '2d, or 3rd 

 Grit Rocks and their Coal-shales, so that siifficient similarity did 

 not remain, in these apparently extreme cases, to ground a con- 

 jecture, as to the identity of this Coal-field with that on the 

 eastern side of Derbyshire. And the same appeared also to be 

 nearly the case, with respect to the Denbighshire and Flintshire 

 Limestone and Coal Fields, as far as my hasty journey across 



* The situation and ctiaracters of this Rock, were fully described in the 

 Spring of 1813, in i.iy Paper and iMaps and Section of the Ashover Dcni*- 

 dation, which hud been pr-omisrd a place in the 2d volume of the Geological 

 Transactions; but were subsequently denied thut Itonour by a Geognoslic 

 faction, see vol. xlii. page 55, Note, and p. ^17, Note. 



thciu, 



