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Theae visits Laving thus made us acquainted with good tjpea of 

 the upper Silurian beds in regular succession, in their most classical 

 localities, the Kington meeting was designed, for the examination 

 of the Nash-scar limestone, near Presteign, and the igneous out- 

 burst at Eadnor and Stannar. The position of the Nash-scar 

 limestone, originally regarded bv Sir Roderick Murchison as the 

 equivalent to Wenlock (= Dudley and Ledbury) limestone, haa 

 given rise to some controversy. Professor Sedgwick, in his first 

 visit to the district, suggested that it was of an earlier date, the 

 equivalent of a lower band, appearing in the centre of the Woolhope 

 valley, and which Sir Roderick had classed as Caradoc or lower 

 Silurian. The Geological Staff of the Ordnance Survey adopted 

 the Professor's views. The question has been carefully investigated 

 by J. E. Daviis, Esq., of the Middle Temple, our honorary associate 

 and happily on this occasion we had the benefit of his presence, and 

 under his direction examined the most interesting points of the 

 district. A paper on the age and position of this limestone was 

 read by him before the Geological Society of London, in May, 1850 

 and which will be found in their journal of Nov. of that year, ip 

 which the question, confessedly one of diflSculty, is very ably dis- 

 cussed. Since the question was mooted, more extended observations 

 have removed the Woolhope limestone from the Caradoc into the 

 Wenlock series; so that the question is now, to which of these 

 bands — viz., the upper or lower Wenlock limestones — is the 

 Nash-scar limestone to be referred. The evidence collected by 

 Mr. Dayi4s, more especially, of the organic remains (for mineral 

 structure quite fails in this case), inclines me to the position origi- 

 nally assigned to it, by Sir Roderick. The Nash-scar affords a fine 

 example cf metamorphic or altered limestone, occasioned by 

 contact with igneous matter, injected against or between the strata, 

 maintaining a high temperature, under great pressure, for a consi- 

 derable time, producing a complete change of mineral structure, 

 destructive of stratification, and in some parts of almost all traces 

 of organic remains. The actual junction of these rocks is not 

 here seen, but the examination of similar phenomena at Radnor, 

 where the igneous rock and limestone are actually fused together, 

 and where traces of organisms are found within a few inches of 

 the junction, leaves no doubt that the causes of these changes are 



