Report on the Geology of the County of Londonderry, and parts of Tyrone and Fermanagh examined and described under the authority of the Master General and Board of Ordnance J E Portlock, published by Millikin, Hodges and Smith, Dublin 1843. In stiff cloth-covered boards size 24 by 15 cm. Uncut. 784 pages. With 38 plates, 9 folding plans and sections (some hand-coloured), plus a large folding hand-coloured OS map. Small faded stamp to title page and rebacked with the original spine. Good to VG condition.