On the Palaeontology oj County Dublin. 1G7 



JVucleobranchiata. 



Belleroplion subdecussatus. 



„ new species, allied to acutus. 



Cephalopoda. 



Orthoceras remotum (Salter mss.) 

 „ species undetermined. 

 „ tennicinctum % 



Annelida. 

 Tentaculites Anglicus. 



Crustacea : Trilobita. 



Agnostus trinodus. 

 ^Eglina mirabilis. 

 **Calymene obtusa. 

 *Cheirurus clavifrons. 



„ bimucronatus. 



**Cybele verrucosa. 

 ***Illgenus Bowmanii. 

 Lichas Hibernicus. 



„ laxatus. 

 Remopleurides longicostatus. 

 *Sphserexochus minis. 

 Stygina latifrons. 

 *Trinucleus seticornis. 



Lower Silurian rocks, with accompanying fossils, are again ex- 

 posed still further north of Dublin, on the coast north and south 

 of Balbriggan. To the south, from half a-mile to a mile of Bal- 

 briggan, the rocks on shoie at several places, black or dark grey 

 slates, contain fossils, mostly Graptolites. The single-celled form, 

 Graptolithus Hisingeri, occurs in profusion, with G. tenuis 

 sparingly, and the double-celled and characteristic form of Dip- 

 lograpsus pristis plentifully. Small orbicular Brachiopods, al- 

 lied to Crania, are occasionally associated with the Graptolites. 



About one mile and a-half north of Balbriggan, the rocks on 

 shore near Lowther Lodge and west of the Cardy Rocks, con- 

 sisting of grey and brown shales, are very fossiliferous ; the small 

 coral Favosites fibrosus, and Brachiopod shells Leptcena sericea, 

 Orthis calligramma and 0. porcata, Strophomena alternata and 

 S. deltoidea being abundant, with the Trilobites Cybele verrucosa 

 Calymene brevicapitata, and a small Phyllopod Crustacean, an 

 undetermined species of Beyrichia. This assemblage of fossils in- 

 dicates strata of Caradoc-Bala age. 



