(op) 
or 
On the Paleontology of Cownty Dublin. 1 
Conchifera. 
Modiolopsis and Orthonota, species undetermined. 
Nucleobranchiata (Heteropoda). 
Bellerophon perturbatus. 
Annutosa : Lehinodermata. 
Crinoid joints and stems. 
Cystidean ? plate. 
Glyptocrinus ; portion of column. 
Paleeasterina ? starfish. 
Annelida. 
Tentaculites Anglicus. 
Crustacea: Phyllopoda. 
Reyrichia complicata. 
Trilobita. 
**Calymene brevicapitata. 
Homalonotus bisulcatus ? 
Lichas laxatus. 
*Phacops Brongniarti. 
Trinucleus concentricus. 
North of Dublin, Lower Silurian fossiliferous rocks of Caradoc- 
‘Bala age again appear on the shore at Portrane, and at Lambay 
Island, County of Dublin; at both these places the lithological 
character of the rocks, black slates and dark grey limestone, with 
their contained fossils, are precisely identical. These black 
slates may be observed on the Portrane shore a little south of 
the first martello tower from the coastguard station, and on the 
east side of Lambay Island, north of Kiln Point. From them 
have been obtained one species of Graptolite, Diplograpsus 
pristis, having a central axis with a double series of cells arranged 
on either side. 
The Silurian limestone is well exposed in prominent cliffs on 
the Portrane shore, at several places between the first and second 
martello towers, south of the coastguard station. These rough 
crags have all the appearance of an ancient coral reef; the chain 
coral, Halysites catenularius, Heliolites, Favosites, and Cyatho- 
phyllum, occur-in profusion, being weathered out by sea and 
atmospheric action, 
. N 
