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at Acton Reynolds, near Shrewsbury;" by Roderick Impey Mur- 

 chison, Esq., V.P.G.S. 



The author refers to former memoirs, read before the Society, in 

 which he pointed out the existence of certain bedded trap rocks, in- 

 terstratified with transition deposits, and of other intrusive trap rocks 

 which have been subsequently injected amid these stratified masses. 

 The Breiddin Hills, west of Shrewsbury, aftbrd examples of both these 

 classes of trap rock, in ridges running from west-south-west to east- 

 north-cast, and also indicate, upon their flanks, that elevations have 

 taken place along tiiese lines, subsequently to the deposition of the 

 adjoining coal measures. The author has lately discovered that still 

 more recent movements of elevation have been propagated along the 

 same line of fissure, posterior to the consolidation of the new red 

 sandstone. He was led to this observation by the unexpected dis- 

 covery of three small trap dykes beneath the house of Sir A. Corbet, 

 Bart., at Acton Reynolds, which were accidentally laid open upon 

 clearing out the foundations of that mansion. 



These dykes cut like walls through the new red sandstone, and are 

 made up of a peculiar greenstone and a mottled concretionary felspar 

 rock, both of which rocks occur in the Breiddin Hills. Besides this 

 similarity in structure, the principal dyke has precisely the same di- 

 rection as the Breiddin Hills, and hence the author was induced to 

 examine the intervening tract of fifteen miles by which these trap 

 rocks are separated. The result has been the detection of an anti- 

 clinal line throughout that space, along which the strata of the new 

 red sandstone are thrown off, both to the south -south-west and north- 

 north-east, or at right angles to the line of eruption of the trap. The 

 clearest and most unequivocal point in the course of this anticlinal line 

 is seen in Pirn Hill, six miles north of Shrewsbury, in the centre of 

 which the sandstone is compact, white, and unstratified, with slicken- 

 sides, coatings of earthy oxide of manganese, traces of copper ores, 

 vertical fissures, &c., whilst strata of unaltered sandstone dip away 

 from this common centre, both to the south-south-west and north- 

 north-east. This point of altered rock lies exactly upon the line 

 connecting the Moel y Golfa ridge of the Breiddins with the trap 

 dyke of Acton Reynolds. The line of elevation is further traceable 

 for about fifteen miles, to the east-north-east of Acton Reynolds, 

 usually throwing the strata into only dome-shaped masses j but the 

 Rev. T. Egerton has observed it passing the Liverpool and Birming- 

 ham canal thirty miles distant from the Breiddin Hills. 



The author is of opinion that the hilly range of new red sandstone 

 extending from the Ness ClifT Hills, by the south of Wem, into the 

 Hawkstone and Hodnet Hills, and then prolonged by the south of 

 Market Drayton into the high grounds of Ashley Heath (parallel to 

 the line extending from Moel y Golfa through Acton Reynolds), has 

 been affected by similar elevatory forces acting along a line proceed- 

 ing from the focus of the principal ridge of the Breiddins, or that 

 on which Rodney's Pillar stands ; and in corroboration of this, he 

 alludes to the veined and metalliferous character of the red sandstone 

 along this line, in which copper ores, manganese, &c. are of partial 



