Yol. 56.] LONGMYNDIAN INLIERS AT OLD RADNOR, ETC. 511 



26. On Longmyndian Inliers at Old Radnor and Huntley 

 (Gloucestershire). By Charles Callaway, M.A., D.Sc, 

 F.G.S. (Read April 25th, 1900.) 



[Plate XXVIII— Map.] 



Contents. Page 



I. The Longmyndian Inlier at Old Radnor 511 



1. Unconformity between the Woolhope Limestone and the Old 



Radnor Series 512 



2. Lithological Characters of the Old Radnor Series 512 



3. Pre-Cambrian Age of the Old Radnor Series 514 



(a) Geological Position of the Series. 



(b) Lithological Comparison with other Groups. 



4. The Alleged Metamorphism of the Rocks of the Old Radnor Area. 515 



(a) The Old Radnor Series. 



(b) The Woolhope Limestone. 



II. The Longmyndian Inlier at Huntley 518 



Introductory. 



The rocks of the Longmynd Hills, in Western Shropshire, originally 

 supposed to be Lower Cambrian, are now admitted to be of pre- 

 Cambrian age. In the following pages evidence will be offered 

 which will enable us to extend the distribution of the Longmyndian 

 system to a considerable distance from the typical area. 



I. The Longmyndian Inlier at Old Radnor. 



The village of Old Radnor is situated on the western slope of an 

 isolated ridge, about | mile long, striking north-east and south- 

 west. The mass of the hill is composed of grit, but there are some 

 associated slaty bands, and on both sides of the ridge the Woolhope 

 Limestone is largely exposed. Murchison x considered the grits to 

 be May Hill Sandstone, and the Woolhope Limestone was supposed 

 to be in conformable succession with it. He perceived, however, 

 that neither grits nor limestone possessed the normal characters 

 of the groups to which he believed them to belong, and he attributed 

 their peculiarities to the metamorphic action of intrusive igneous 

 masses. On the Geological Survey map, the arenaceous series 

 is described as ' altered sandstone, 7 and identified as May Hill 

 Sandstone. 



Many years ago, I was struck with the close lithological resem- 

 blances between the Old Radnor Series and some parts of the 

 typical Longmyndian, and I could not acquiesce in the view that 

 the rocks were ' altered ' in the sense of being truly metamorphic ; 

 but it was not until the summer of 1897 that I ascertained the 

 existence of a clear break between the Woolhope Limestone and the 

 Old Radnor Series. This discovery enables me to complete my 

 evidence for the Longmyndian age of the latter. 



1 'Siluria' 4th ed. (1867) p. 108. 



2m2 



