Glenveagh Granite

Notes:

Foliated, durable, not too hard, biotite-rich granite (Kinahan, 1889, p. 456). "The foliated granite and gneiss of this area do not, as a general rule, afford good stones for dressed work; for although they will split and dress well in one direction, they split more or less hackly across, and spawl off instead of dressing. With careful selection, however, some courses will be found to yield stones that dress on every face. Such a stone has been used in building the castellated mansion of the Adairs at Glen Beagh [Glenveagh]; and we learn from the report of Mr. J. Cockburn, of the Board of Works, that the gneissose granite has been used in the building throughout for dressed and punched work, and for walling purposes." (GSI Memoir to accompany sheets 3, 4, 5 (in part), 9, 10, 11 (in part), 15, 16 North-west and Central Donegal, 1891, p. 119). This granite is part of the Main Donegal Granite Formation which formed during the Caledonian (Siluruan-Devonian).