83 KEPORT — 1873. 



members (the Corby sandstones) ; and on tlie west side of the Eden the gypsiferous 

 red clays have been extensively worked. Another fault gives rise to the presence 

 of these strata, which have a strike nearly E. and W. This latter fault, having a 

 direction nearly parallel to the strike of the strata, can be well seen in Shalk beck 

 near Curthwaite Station, on the Maryport and Carlisle Eailway, where it exhibits 

 a downthrow on the north side. 



On the Areniij and Llandeilo Bocks of St. David's. By Henry Hicks, F.G.S. 



The author mentioned that the object intended in the paper was to follow out 

 the succession of the rocks in the neighbourhood of St. David's, commenced in pre- 

 vious papers communicated at various times to the British Association. By the 

 present paper the section was completed to the top of the Llandeilo series. 



The author divided the Arenig group into an upper and lower series, and the 

 Llandeilo gi'oup also in the same manner, believing that in each case there was 

 suiBcient evidence to enable him to do so. 



The Loiver Arenig Series, it was stated, occur as black slates and flags, about 

 1000 feet in thickness, and exposed at the north end of Ramsey Island and at 

 Whitesand Bay, resting conformably in the former place on Tremadoc rocks, but 

 separated from them in the latter by a fault. They are characterized by a large 

 number of species of dendroid Graptolites, as well as by numerous species of trilo- 

 bites entirely restricted to the series. 



The Uj}per Arenig Series occur <is fine-grained, soft, black shales, also about 1000 

 feet in thickness. They are found at the south end of Ramsey Island and at White- 

 sand Bay, where they rest conformably on the Lower Arenig series, and again on 

 the north coast of Pembrokeshire, where they support the Lower Llandeilo rocks 

 of Aberiddy Bay. The Graptohtes of this series are totally distinct from those 

 found in the lower beds, as are also all the other fossils. Didymograptus hijidus, 

 gemintis, and affinis are characteristic of this zone. 



The Lmver Llandeilo Series, the lowest rocks recognized by Sir R. Murchison in 

 the typical Llandeilo district, and hence called by him Lower Llandeilo, occur at 

 St. David's as black slates and hard grey flaggy sandstones with siliceous schist and 

 beds of felspathic ash at the lower part, and as dark slates and flags, with nume- 

 rous calcareous bands in the upper. They are about 1500 feet in thickness, and are 

 chiefly found on the south coast of Aberiddy Bay, resting conformably on the upper 

 Arenig rocks. The most characteristic fossils of these beds are I)idgniograptus 

 Mu7-chisoni, Diiilograptus pistis, Asaphus tyrannus, Calymene camhrensis, and Illesmis 

 perovalis. 



The Upper Llandeilo Series occur as black slates and flags several thousand 

 feet in thickness, forming several folds of strata in a direction north of Aberiddy 

 Bay, at which place they rest conformably on the Lower Llandeilo series. The ty- 

 pical fossils are Ogygia Buchii, Barrandia Cordayi, Calymene dnplicata, Chei)-ttrus 

 Sedgwickii, Trimwleus Jimlriatus, Ampyx nudics, and Lingula Bamsayi. 



The author doubted whether any other spot hitherto examined in Britain could 

 show so continuous a section of these rocks ; still he believed that there was ample 

 evidence to prove, from researches made in other parts of Wiiles and Shropshire, 

 that the succession here made out was in most of its important details capable of 

 being applied to many other districts. 



On some Graptolites from the Upper Arenig Bods ofBamsey Island, St. David'' s. 

 By John Hopkinson, F.G.S. , 'F.BM.S. 



At the Meeting of the British Association at Brighton last year the author had 

 announced the discovery of a considerable number of Graptolites in the Ai-euig 

 rocks of Ramsey Island and Whitesand Ba}', near St. David's, and had shown that 

 these rocks were more nearly allied by their Graptolites to the Quebec rocks of 

 Canada than to their British representatives, the Skiddaw slates of Cumberland and 

 the Arenig rocks of Shelve. 



Since then a new series of fossiliferous beds had been discovered on Ramsey 

 Island ; and the Graptolites collected in them had been intrusted to the author for 



