Quart. Journ. Geol. Soc, Aug. 1911.J 



[To face p. 44(5. 



Table illustrating the Correlation of the Orhovician and Silurian Rocks of North-Eastern Montgomeryshire with those of other Areas. 



Series. 



South Wales. 



North-Eastern 

 Montgomeryshire. 



Caradoe. 



Central "Wales 

 (Khayader). 



Worth Wales 

 (Conway). 



Lake District. 



Southern Scotland 

 (Girvan Area). 



(" Ludlow. 

 Salopian. < 



{_ Wenlock. 





Zones of 

 fi. M. leintmardinensis ! 

 Yr Allt J 3. M. scaniens. 

 ffeds. ] 2. M. nilssoni. 

 [\. M. vulgaris. 



C4k. Curloqr. Inii-dqreni. 

 Wenlock 1 3. C. rigidus. 

 Shales & 1 2. C. linnarssoni. 

 Limestone. (^1. M. riccartonensis. 







Benarth Flags and Grits 



Coldwel] Flags. 

 Coldwell Grits. 

 Brathay Flags. 



Mudstones and shales ol 

 Lanark. 



Straiton and Bargany 

 Reds. 



f Tabannon. 

 VaIiBNTIAN. -\ Uphbb Llakdoveet. 

 t Lowun Li.anhoyeey. 



Green nmdstones 



& grits. 

 Shales anil 



sandstones. 

 Unfossiliferous black 



shales. 



Buttington Shales. 



Cloddiau Mudstones. 



Powis-Castle Conglomerate 

 and 

 Limestones. 



Tri nucleus Shales. 



Rhayader Pale Shales. 



Caban Group. 

 (Unconformity,! 

 Gwastaden (iron]). 



Gyffin Shales. 



Conway-Castle Grits. 



Deganwy Mudstones. 

 Bodeidda Mudstones. 



Browgill Reds. 

 Skelgill Beds. 



Parkhill Group. 



Canvegan Group. 

 Saugh Hill Group. 

 Mullock Hill Group. 



Amiiiir.i.rAN. 



Slade Beds. 

 Redhill Beds. 

 Sholeshook Limestone. 



Robeston Wathen 

 Limestone. 



(Unconformity.) 



fBlack shales. 



Gwern-y-brain J 

 Group. 



[Limestone. 



Cleaved black shal 





Phyllopora Beds ? 

 AshgiU Shales. 



S/a/irocephalus 

 Limestone. 



Drummuck Beds (with 

 Staurocephalus). 



CaBAUOCIAN. 



Glenkiln-Haetfell. 



J)it'rituograptus 

 Shales. 



[^Limestone and ashy 

 | grits. 

 Gaerfawr J 

 Group. I 



I^Grits and Hags. 

 Pwll-y-glo Group. 



Acton-Scott Beds. 

 Longville Flags. 

 Cbatwell & Soudley 



Sandstones. 

 Hoar-Edge Grits. 

 Harnage Shales. 







Upper Cadnant Shales. 



f 



Sleddale ■{ 



IC 

 U 

 and 



pplethwaite Shallock Flags. 

 Limestone. | 



.' Whitehouse Beds, 

 onglomevate. 

 tile-End Beds. Ardwell Flags. 



("Grits and 

 Balclatchie Beds. J. sandstone. 

 [. Shales. 



Trilohite- Dingle Shales. 







Lower Cadnant Shales. 



Group. 























