On the Paleontology of County Dublin. 167 
Nucleobranchiata. 
Bellerophon subdecussatus. 
“53 new species, allied to acutus. 
Cephalopoda. 
Orthoceras remotum (Salter mss.) 
species undetermined. 
tenuicinctum 4 
9 
9? 
ANNELIDA. 
Tentaculites Anglicus, 
Crustacea: 7rilobita, 
Agnostus trinodus. 
Afelina mirabilis. 
**Calymene obtusa. 
*Cheirurus clavifrons. 
“f bimucronatus. 
**Cybele verrucosa. 
***Tlenus Bowmanil. 
Lichas Hibernicus. 
3 laxatus, 
Remopleurides longicostatus. 
*Spherexochus mirus. 
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 shore at several places, black or dark grey 
slates, contain fossils, mostly Graptolites. The single-celled form, 
Graptolithus Hisingert, 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 Craiia, 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 aud brown shales, are very fossiliferous; the small 
coral Favosites fibrosus, and Brachiopod shells Leptena sevicea, 
Orthis calligramma and O. 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. 
N 2 
