Feacle Turlough Co. Roscommon
County Roscommon south of a line that runs east-northeast from Ballyforan — the dotted line on the map to the left — is a land dominated by depositional glacial landforms. These reach their acme in the low range of hills that stretch southwest from Cam Hill, near Brideswell. These hills are formed of morainic material, a poorly sorted mixture of clay, sand, and rounded limestone cobbles and boulders, left behind in apparently random heaps as the glaciers melted. Where the land has escaped bulldozing there is an amazing boulder-strewn landscape with small stone-walled fields, particularly well seen beside the L12 road south of Thomas Street.
the west end of Feacle Turlough, looking northeast
Feacle Turlough lies just south of these hills, occupying a low depression. In summer it is a broad grassy area, with no trees or bushes, and stone walls covered with the dark brownish-green turlough moss Cinclodotus. In winter the turlough fills with water, fed by links — possibly a swallow-hole (I don't know specifically how in this case) — with the groundwater system. A diagram in the booklet "The Karst of Ireland" [which will be available shortly on this website] shows the characteristic features of a turlough [But note that the peat layer shown on the diagram is a very unusual feature for a turlough - none of the classic turloughs of the Gort area have associated peat].
fields sharing the residual water
One point of interest here is the direction of movement of the underground water. Killeglin Springs, the main supply of water for south Roscommon, lies 4km to the southwest. In order to protect the quality of its water we must find out where that water comes from. The probable source area is that to the north and east of Killeglin, where there is little or no surface water except in winter.
Three characteristic features of turlough vegetation:
• near the top of the wall is the dark "turlough moss", Cinclodotus fontinaloides — the upper limit of this moss is a quick guide to the upper limit of winter flooding
• dessicated algal mats are draped against the lower part of the wall. These grow as green "scum" on the water, which as the turlough dries up are left high and dry
• at the base of the wall Potentilla anserina (Silverweed), the underside of whose leaves is white (see detail below)
Potentilla anserina in flower