426 



MR. A. WADE ON THE LLANDOVERY AND [^Ug. I9II 



List op Fossils ebom the Pwll-y-glo Beds 

 (see p. 425). 



Asaphus powisi Murchison 



Somalonotus bisulcatus Salter 



Illcenus cf . boiomanni Salter 



Illcenus davisi Salter 



Salteria primceva Thomson 



Trinucleus concentricus Eaton 



Trinucleus cf. concentricus Eaton 



Trinucleus concentricus, var. caractaci Murch. ... 

 Trinucleus concentricus, cf. var. portlocki Salter. . 



Trinucleus jimbriatus Murchison 



Trinucleus aff. nicJwlsoni Reed 



Beyrichia (Tetradella) complicate*, Salter 



Climacograptus cf . bicomis Hall 



Diplograptus (Orthograptus) cf. rugosus, var. 



apiculatus Elles & Wood 



*D. (O.J pageanus, var. micracanthus Elles & Wood 



D. (O.) calcaratus, var. vulgatus Lapworth 



Cyathocrinus quinquangularis Phillips .1 



Sphceronites sp 



Ortlioceras vagans Salter 



Bellerophon (Oxydiscus) acutus Sowerby 



Carinaropsis acuta Ulrich & Scofield 



Bellerophon (Protowarthia) cf.pervolutusXJ.&S. 

 BelleropJion (Protoivarthia) aft", nodosus Sow. ... 



Anodontopsis bulla M'Coy 



Ctenodonta cf. coarctica Phillips 



Ctenodonta cf. anglica d'Orbigny 



Ctenodonta cf. longa Ulrich 



Vanuxemia sp 



Orthonota aff. amygdalina Sowerby 



Leptcena rhomb oidalis Wilck 



Orthis (Balmanella) testudinaria Dalm 



Orthis (Herbertella) vespertilio Sowerby 



Annelid tubes 



9 S 



Pi 



<3 ri? 



X 



X? 



X 



X? 



* From J. Bickerton Morgan's Collection. 



The Gaerfawr Group, consisting of hard, greenish, micaceous grits 

 and flags with a few thin shale-partings, occupies the centre of the 

 syncline which forms the ridge at Pwll-y-glo. Only a small thickness 

 of the beds occurs here, the remainder having been removed by denu- 

 dation. Across the valley, however, they form the wooded ridge of 

 Harriets Hill, and terminate at a fault on the south at Y Frochas. 



The grits cross the road at Cloddiau, and swing round so as to 

 strike exactly at right angles to their direction in Harriets Hill. 

 This change in the direction of the strike is very remarkable. It 

 causes the ridge of Moel-y-garth to cut across the general line of 

 all the surrounding hills in the district. 



