The Llandovery and Associated Rocks of North-Eastern Montgomeryshire

Abstract

I. I ntroduction . T he district investigated is one which was well loved by Murchison, who paid many visits, about the year 1836, to Powis Castle while preparing his great work on the ‘Silurian System.’ It extends for a distance of over 7 miles in a north-easterly direction from a point a mile or so south of Welshpool in Montgomeryshire, and includes a tract of country embracing the Vale of Guilsfield, and a portion of the valley of the Severn. It is bounded on the west by the watershed of the Vyrnwy, the area covering nearly 40 square miles. The country may be broadly described as consisting of three parallel ridges of Silurian rocks running in a north-north-easterly direction, with two wide intervening valleys containing subsidiary though usually more precipitous ridges, formed by the escarpments of rocks of Ordovician age. It was among these fertile valleys and finely wooded hills that De Quincy found solace during part of his early wanderings. II. H istorical R eview . Murchison, in 1839, was the first to give any account of the structure of this region. Speaking of the whole of the country between the Breiddens and the Berwyns, he describes [1] the Silurian strata as lying in undulations or troughs ........ constituting a number of parallel anticlinal and synclinal lines.' (Ch. xxiv, pp. 300 et seqq .) Of the particular district with which I now propose to deal he has much to say. He describes very fully the Welshpool Dyke, and notes its apparent effect upon the strike