1. Report of an excursion to the Portmadoc and Criccieth district of southeast Caernarvonshire;Fearnsides;Proc. Geol. Assoc.,1912
2. The brachiopod Foliomena Fauna in the upper Ordovician Ballyvorgal Group of Slieve Bernagh, County Clare;Ball;J. Earth Sci. R. Dubl. Soc.,1980
3. The Ordovician succession near Llanystwmdwy, Caernarvonshire;Harper;Liverpool and Manchester geol. J.,1956