Notes on the Geology of Killary Harbour

Abstract

The Rosroe Peninsula, on the south side of Killary Harbour, Co. Galway, is formed of the Rosroe Grits, mapped by the Geological Survey of Ireland (1875) as “Lower Silurian”. Kilroe (1907) in a rapid revisionary survey of Galway and Mayo, described the succession on Rosroe as inverted (op. cit. p. 154, n. 3):—“ Mr. McHenry informs me that the fossils (graptolites) on the south side are indicative of Upper Llandeilo, while those on the north side are Lower. This being the case, the order of the beds is inverted, as they dip northerly.”