The topography of the Abbey district derives from a post glacial landscape. Drumlins, crag and tail formations, moraines and eskers are present indicating an ice flow direction NW-SE. Scattered in the hollows between these glacial till formations are several wet areas and natural springs.
At the boundary of the three townlands – Lisdurra, Eaglehill and Tomanynabraher is an area of reedmarsh surrounded by natural regenerating woodland. The marsh is formed on undifferentiated lake sediment (Lacustrine type soils) as defined by Teagasc. This soil type is formed when the still water in lakes permits very fine particles (fine sand, silt, and clay) to settle out and to form deposits. These deposits are fine, very well sorted and have a low permeability which leads to the retention of surface water. The marsh at this location is likely to be the remains of a post glacial lake that covered a much wider area. The surface water may be supplemented by underground springs, which are abundant in this region. Today the underlying soils and surface water support a reedmarsh with a dominant vegetation type of reedgrass, sedges, horsetails and willowherb. The reedmarsh is surrounded by a naturally regenerated woodland of willow and hazel and ash on the higher and drier ground to the south and south east. A conifer forestry plantation is located to the east. To the west is open agricultural grassland grazed by cattle. Similar smaller reedmarsh areas occur in Tomanynabraher, Kylemore and Ballygowan.