232 MR. L. D. STAMP OX THE HIGHEST [vol. lxXlV, 



interest in a consideration of the Bucknell district. In the section 

 {op. cit. p. 208) illustrating the sequence at Downton-Castle Bridge 

 the beds are described as ' Ea, unfossiliferous sandy shales.' When 

 visiting this locality I noticed that these beds are quite unlike any 

 others to be found in the neighbourhood ; they are thinly-bedded, 

 brittle, dark-grey shales tending to have a wavy surface, and readily 

 splitting into very thin laminae. A silveiy sheen is imparted to 

 the surfaces of these laminae hj the presence of fine-grained 

 micaceous material. These silvery shales are succeeded by the 

 Platyschisma Band which is here, in addition, a bone-bed (the 

 Downton Bone-Bed). The Platyschisma Band in all the above- 

 mentioned sections is overlain in turn by massive Downton-Castle 

 Sandstone. 



These shales, comparatively insignificant in the Ludlow area, 

 become of considerable importance in the Bucknell district. In 

 the east of the area mapped, one fairly-continuous section of the 

 transition-beds from the Upper LucHoav rocks to the Temeside 

 Shales is exposed. This section will be described in detail later. 

 There is no trace of the Ludlow Bone-Bed here, and the greenish 

 Upper Chonetes Beds pass up gradually into the silvery Platy- 

 schisma Shales. These in turn pass into micaceous tilestones 

 (yellow thinly-bedded Downton-Castle Sandstone), which become 

 more massive and finally assume a greenish tint in the upper part 

 of the group. The sandstones are followed, somewhat abruptly, by 

 greenish rubbly marls belonging to the Temeside Shales. 



Farther west are three outliers of ' Old Bed Sandstone ' marked 

 on the Geological Survey maps (|-inch index-map, Sheet 14)-. 

 See sketch-map, fig. 1, p. 222. One of these outliers, which may 

 (for convenience) be termed the Five Turnings Outlier, is small — 

 about a mile long and half-a-mile broad — and is situated about 

 a mile north-east of Knighton. A second, the Clun Outlier, 

 is of greater extent, and stretches northwards from the Redlake 

 Valley, north-west of the little village of Chapel Lawn, to beyond 

 Clun. The third — the Bettws-y-crwn Outlier — is seen on the 

 north-west. An examination of the Five Turnings Outlier and the 

 south-eastern margin of the Clun Outlier has disclosed the following 

 succession : — 



Old Bed Sandstone (r).' Purplish-red sandstone. 



I" ' Fragment-Bed ' and shales. 

 Temeside Shales. i Olive-green rubbly shales. 



[_ Micaceous green sandstone. 



f Yellow tilestones. 

 Downton-Castle Sandstone. < Yellow sandstone. 



I Platyschisma Shales. 



Chonetes Beds. Greenish mudstones. 



The Downton -Castle Sandstone Series is here of particular interest, 

 and presents a notable development from the corresponding beds in 



1 See note, p. 242. 



