the Fiice of the Earth in North Waks, {sfc. 223 



fpar, as in the vale of Conway, at Llangynnog, and the Snailbeach mines ; they are fre- 

 ijuently alfo found in Ilmeftone as at Llanymynech and Holywell. Refpefling the forma- 

 tion of the above-mentioned metals, it is not eafy to give a tolerably probable opinion; 

 it appears, however, that cai-bonate of copper is of confiderably htcr formation than the 

 fulphuret, the former probably originating from the decompofition of the latter, and de- 

 riving its acid from the carbonate of lime, in which it is found. It is not likely that the 

 lead found in Ilmeftone was originally formed elfewhere, becaufe lead, even in flate rocks, 

 lies in a matri.x of calcareous fpar-; and efpecially becaufe it does not form thin ftrata be- 

 tween the ftrata of lime, as is the cafe with copper, but it traverfes, in a ftream, the feveral 

 ftrata without any alteration in the' line of its direflion ; to which may be added, that ful- 

 phuret of lead is the general ftate in which the metal is found, both in the flate rocks and 

 Ilmeftone, the carbonate being equally rare in both fituations. 



There is no coal found in North "Wales between the primitive mountains and the flates : 

 a very fmall quantity is procured between the Hates and limeftone ; but by far the moft ex- , 

 tenfive beds are between the limeftone and the fand rocks, as about Wrexham or Coalbrook. 

 D.de, or between thefe laft and the alluvial hillsj as round Wolverhampton. 



V. From the above-mentioned circumftances it would appear, tl'at at fome former period 

 the fea covered the whole of North Wales, of the prefent plain of Salop, and of Chediire, 

 except a line of iflands confiding of the Snowdon chain, another to the fouth confifting 

 of the prefent Cader Idris chain, and a few detached rocks, feveral leagues to the eaft» 

 which now form the tops of the Wreakin, Caer Caradoc, and Stiperftones. Under this 

 primitive fea, and prior to the exiftence of animals or vegetables, the vaft banks of flate 

 appear to have been formed. My reafons for thinking that animals and vegetables had as 

 yet no exiftence are, becaufe there was no foil upon thefe hard infufated rocks for the growth 

 of plants upon which the animals might feed, and becaufe we meet with no impreflions or 

 remains of organized bodies in the primitive mountains or banks of flate. By flow di-grecs 

 the water fubfided ; being poffibly in part abforbed by the earth, in part fixed in a folid 

 form in the flates, and in part decompofed, forming oxygene and hydrogene : the former of 

 which conftituted the oxygenous bafe of the lower atmofphere ; the latter, by its fuperior 

 levity, rlCng above the atmofpherical air, according to the opinion of fome philofophers,. 

 forms a vaft ftratum many miles above the furface of the earth ; whence originate meteorsj^ 

 the aurora borealis, and other fimilar appearances. 



The wat^r having for the moft part retired from the beds of flate, the greater part of 

 Wales, and the fecondary hills of the Englilh counties weft of the Severn, would form one 

 or more confiderable iflands, feparated from the fmall part of England then above water by 

 a wide channel occupying the flat part of Cheftiire and Shropfhire, and the prefent vale of 

 the Severn from Coalbrook Dale to the Briftol Channel. At this period I imagine tlie 

 fccondary limeftone hills to have been formed. The deCccation of the water ftill continu. 

 ing, the tops of the limeftone ridges themfeives would begin to appear above the furface; 

 and tlicn the plain of Salop, the flat part of Cliefliire, and the fouthera extremity of 

 Lancaftiirc, would form one vaft bay ; into which the Severn, Dee, and Mcrfcy emptied 

 tliemfclvcs, flowing into the fea by an united llreani, filling the prefent, mouths of the two 

 latter rivers, and the intermediate fpace, the hundred of Wirral. Into this bay or cftuarj« 

 a large quantity of fand would be tonftantly poured in by tlie \i(jknt wcftern winds, and 



the 



