173 H. HICKS ON THE SUCCESSION OP 



Stiper Stones the fauna is exceedingly like that in the Upper Arenig 

 group at St. David's, and contains, like it, the genera Illcenus and 

 Lllcenopsis, in addition to most of the genera found in the beds 

 at Ty-Obry, in Carnarvonshire. 



List of Fossils from the Arenig Group, St. David's. 



Lower Arenig. 

 Name. Localities. 



Asaphus Homf rayi, Salt Creek north of Trwyn-hwrddyn, White- 

 sand Bay. 



Ogygia scutatrix, Salt Ditto. 



Trinucleus, sp Ditto and Eoad-uchaf, Ramsey Island. 



Lingulella Davisii, M' Coy Ditto, ditto. 



Lingula petalon, Hides Ditto, ditto. 



Orthis lenticularis, Dahn Ditto. 



Obolella plicata, Hicks Ditto and Eamsey Island. 



Conularia Homf rayi, Salt Ditto, ditto. 



Didymograptus extensus, Hall Eoad-uchaf, Ramsey Island. 



pennatulus, Hall Ditto. 



sparsus, Hopk Ditto. 



Phyllograptus stella, Hopk Ditto. 



Trigonograptus ensiformis, Hall Ditto. 



truncatus, Lapw Ditto. 



Ptilograptus cristula, Hopk Ditto. 



Hicksii, Hopk Ditto. 



Dendrograptus arbuscula, Salt. MS.... Creek north of Trwyn-hwrddyn, White- 

 sand Bay. 



divergens, Hall Eoad-uchaf, Eamsey Island. 



— — flexuosus, Hall Ditto and Whitesand Bay. 



persculptus, Hopk. Creek north of Trwyn-hwrddyn, White- 

 sand Bay. 



diffusus, Hall Eoad-uchaf, Earn sey Island. 



Callograptus radiatus, HopJc Creek north of . Trwyn-hwrddyn and 



Eoad-uchaf. 



1 radicans, Hopk Ditto, ditto. 



Dictyonema cancellata, Hopk Ditto. 



I Homfrayi, Hopk Ditto. 



Middle Arbnig. 



Agnostus hirundo, Salt « Slate-quarry, north side of Whitesand 



Bay, and south side of Porth Melgan. 



Ampyx Salteri, Hicks Ditto. 



iEglina grandis, Salt Ditto. 



: Boia, Hicks Ditto. 



Calymene, sp Ditto. 



Cheirurus, sp Ditto. 



Ogygia peltata, Salt Ditto. 



bullina, Salt Ditto. 



Trinucleus Gibbsii, Salt Ditto. 



■ Sedgwickii, Salt Ditto. 



Lingula petalon, Hicks , Ditto. 



Orthis, sp Ditto. 



Siphonotreta, sp. Ditto. 



Theca Harknessi, Hicks Ditto. 



Orthoceras sericeum, Salt Ditto. 



Bellerophon multistriatus, Salt Ditto. 



Didymograptus patulus, Hull Ditto, 



