364 DR. A. H. COX ON A LONGAIYNDIAN [Sept. I9I2, 



20. On an Iistlier of Lotstghykdian and Cambrian Rocks at 

 Pedwardine (Herefordshire). By Arthur Hubert Cox, 

 M.Sc, Ph.D., P.G.S. (Bead February 7th, 1912.) 



Contexts. 



Page 



I. Introduction 364 



II. The Brampton Grits and Conglomerates 365 



III. The Lictyonema ^\\2i\es 369 



IV. The Letton Grits and Conglomerates 369 



y. The Structure 370 



VI. Summary 371 



I. Introduction, 



The inlier under consideration occupies a small strip of country, 

 about a mile in length, around the hamlet of Pedwardine, near 

 Brampton Bryan, a village situated on the Ludlow-Knighton road, 

 11 miles west of Ludlow and 6 miles east of Knighton. 



Through the district in question passes the great north-east and 

 south-west line of disturbance which, extending through Lilleshall, 

 Church Stretton, and Old Radnor, brings up the older formations at 

 so many points along its course. 



The presence at Pedwardine of Cambrian shales with Dictyonema 

 was first mentioned by Lightbody,^ who observed that at one point 

 these shales are covered unconformably by ' Llandovery.' Their 

 occurrence at this locality is also noticed by Murchison,^ Callaway,^ 

 and La Touche,'^ the last-named observer referring in addition to the 

 * Cambrian grits and pre-Cambrian rocks ' seen in Brampton Bryan 

 Park (o^:>. cit. p. 25). 



Despite these early records, no attempt appears to have been 

 made to fix the boundaries of the Cambrian beds, or to ascertain 

 their relations to the surrounding formations. Further, the name 

 ' Cambrian ' does not appear on the old 1-inch map of the Geo- 

 logical Survey.^ In that map the whole strip is coloured as ' Llan- 

 dovery,'* succeeded conformably by AVenlock Shales on the east, and 

 faulted against Ludlow beds on the west ; but the word ' Fossils,' 

 which is written across the strip, would appear to refer to the 

 Dictyonema^ which is abundant in the Cambrian shales. 



The district is dominated on the western side by the eastward- 

 facing Ludlow escarpment, which ranges north and south through 

 Brampton Bryan Park and Pedwardine Wood, where it rises to an 



1 'The Geologist = vol. iii (1860) p. 462. 



'^ 'Siluria'5th ed. (1872) p. 45. 



3 Q. J. G. S. Tol. xxxiii (1877) p. 659. 



* ' Handbook to the Geology of Shropshire ' 1884, p. 14. 



5 Old Series, Sheet 56, N.E. 



