Vol. 68.] AND CAMBRIAN INLIEK AT PEDWAKDINE. 369 



to a much greater extent by earth-movements than have the im- 

 mediately adjacent Bala Beds. 



Thus, in the entire absence of fossils and taking account of the 

 close resemblance to some of the typical Longmyndian beds, in con- 

 junction with other field evidence, I have no hesitation in assigning 

 these Brampton Grits and Conglomerates to the Longmyndian. 



In this connexion it may be noted that the Brampton Grits differ 

 in appearance, although not in composition, from the series found 

 along the same line of dislocation 9 miles to the south-west at Old 

 Radnor, a series claimed as Longmyndian by Dr. Callaway.^ These 

 Old Radnor rocks have, however, evidently been subjected to much 

 greater disturbance, as shown by the prevalence of slickensiding 

 and brecciation, resulting in the complete obliteration of all bedding- 

 planes. 



III. The Dictyoxema S bales. 



The Dictyonema (Upper Cambrian) Shales occupy the ground on 

 the eastern side of the outcrop of the Brampton Grits and Con- 

 glomerates. They are best exposed in the deeply-cut course of a 

 small stream, alongside the field-path running from the Brampton 

 Bryan-Lingen road to Upper Pedwardine. Here they are seen to dip 

 steeply (up to 50°) westwards, that is towards the Brampton Grits. 



These Dicti/onema Beds are thinly-bedded greenish shales, precisely 

 similar to the typical Dictijonema Shales of Shineton.^ Dictyonema 

 sociale is fairly abundant, and Lingulella nicholsoni also occurs ; but 

 no other fossils have been recorded. 



Other smaller exposures show the dip of these beds to be rather 

 inconstant. Por example, there is a small fold near the road, 

 perhaps due to the close proximity of the boundary-fault; while, in 

 an exposure on the south side of the same field, the beds appear to 

 be horizontal. 



IV. The Letton ^ Gkits and Conglomerates. 



The Letton Grits and Conglomerates are seen resting on a planed- 

 off surface of the Dictyonema Shales at the first-mentioned exposure 

 of the latter. These are the beds referred to as 'Llandovery' by 

 Lightbody,'* Callaway,' and La Touche.'' Only a few feet of these 

 beds are exposed. They are conglomerates and coarse grits, the 

 conglomerate consisting essentially of well-rounded quartz-pebbles, 

 with an occasional rather greenish quartzite-pebble evidently derived 

 from the Cambrian quartzite, although this latter is not exposed 

 anywhere within 10 miles of Pedwardine. These Letton Conglome- 

 rates yield numerous casts of Orthis calligramma, which are for the 



^ Q. J. &. S. vol. Ivi (1900) p. 511. 

 2 C. Callaway, ibid. vol. xxxiii (1877) pp. 659-60. 



^ Letton is a hamlet situated about three-quarters of a mile east of Upper 

 Pedwardine. 



* ' The Geologist ' vol. iii (18G0) p. 462. 



5 Q. J. a. S. vol. xxxiii (1877) p. 659. 



^ ' Handbook to the Geology of Shropshire' 1884, pp. 14, 25. 



