Com Sathairn
Horseshoe.

Loch Chom Sathairn

Coomasaharn is the lake. The Placenames Database gives it as Loch Chom Sathairn, the lake of Com Sathairn, which is the townland it lies in, in the parish of Glanbehy. It is one of a run of coum lakes strung along this side of the mountain: Coomaglaslaw to the north-west, Coomnagrossaun to the east, Coomacullen and Coomeeneragh to the south.

The carved boulder

Forty metres off the line, near the end of the loop, a sandstone boulder sits in a turf bank at the edge of an old bog trackway, 185 metres up, looking north-east across the Behy valley towards Glenbeigh. Its north face is carved. The Iveragh survey recorded a cup with two rings and a radial groove, and three meandering grooves running off it, one of them nearly the length of the stone. Above that it listed nine more cup-and-rings, another cup-and-two-rings, three cupmarks with radial grooves and five plain cups.

Somebody also cut the letters M, Q and I into the rock. O’Kelly noted them in 1958 and Finlay in 1973. When the site was looked at again in 2017 only the I could still be found, and most of the carving had gone under bog, vegetation and lichen. What is left to see is one long meandering groove.

Eleven more panels

That boulder is not alone. Eleven more carved panels are recorded within a hundred and fifty metres of this line, the nearest four metres off it. Five metres off the track is a large angular boulder with three V-shaped grooves cut across its north-west face, a possible cupmark and two solution pits beside them; O’Kelly thought the grooves were for sharpening pointed implements.

Fifty-two metres away, on sloping pasture above the lake and marked on no Ordnance Survey map, is a cashel: a stony mound just under sixteen metres across with stone facing still standing nearly a metre at the south-east, an entrance flanked by two low uprights and a souterrain running under its western half.