1853.] SALTER LOWER PALEOZOIC FOSSILS. 177 



Notes on the Fossils. By J. W. Salter, Esq., F.G.S. 



The ' Lingula Flags ' contain, at Dolgelly, Trawsfynydd, Ffestiniog, 

 and Tremadoc, as stated in the Reports of the Brit. Assoc. 1852 

 (Trans. Sect. p. 57), 



Hymenocaris vermicauda. Olenus micrurus. Lingula Davisii. 



The last ranges upwards through a great part of the igneous series. 



Near Llanberis and Bangor the Olenus and Lingula are still found, 

 and with them two fucoids, 



Cruziana semiphcata. Chondrites acutangulus ? 



Fucoids are also said by Prof. Sedgwick to abound at Tremadoc, 

 Ffestiniog, and Dolgelly. 



In the black slates at Pont Seiont, Caernarvon, there occur 

 Fragments of Crustacea, and Graptolites (Didymograpsus Mm-chisonBe?) ; 

 and at the Bath-house, Bangor, in similar black slates, 



Bellerophon perturbatus (Euomphalus, Sil. Syst.), a single specimen. 



The higher parts of the igneous series have yielded fossils at two or 

 three points only : — Tai-hirion, Arenig-bach ; and four miles N.E. 

 of Dolgelly. 



Asaphus Selwynii. Calymene parvifrons. Lingula — probably L. Davisii. 



The black slates above the igneous rocks of the Arans and Arenigs, 

 though well-adapted for the preservation of Graptolites, have yielded 

 scarcely any, but in their lowest beds, immediately over the igneous 

 rocks of Arenig-bach, are numerous fossils, first discovered by Pro- 

 fessor Ramsay, and exactly like those of Bala, mentioned below. 



The Snowdonian slates, as exhibited in the Pass of Nant Francon, 

 are full of fossils — occurring in five or six bands between the beds of 

 ash and felspathic traps ; and are all of species common in the Bala 

 limestone, and distinct from those of the Lingula beds below. Prof. 

 Sedgwick has described this great " fossiliferous trough, half a 

 mile wide, which ranges from this point through the highest parts of 

 the Caernarvon chain," and has given some of the fossils. 



Calymene Blumenbachii and C. Orthis flabcUulum* and O. ele- 



brevicapitata, gantula, 



Homalonotus bisulcatus, Leptsena serieca, 



Lichas laxatus, Rhynchonella serrata*, 



Triuucleus concentricus, Murcbisonia scalaris*, 



Beyricbia complicata. Turbo crebristria, 



Tentaculites annulatus, Bellerophon ornatus, and B. cari-; 



Strophomena expansa* and S. natus?*, 



depressa, Modiolopsis, 2 or 3 species, 



Stenopora fibrosa, 

 are the prevailing fossils, and all but one are common at Bala. 



* These are in great abundance. 



