
Gortnacowly, referred to evocatively in the 1899 trace for the 1902 O.S. Name Book, as “four standing stones of druidical antiquity”.
I’ve altered the plan to show an arc of possible positions for the absent stone which would probably have been located on the eastern side south of an axis line running northeast to southwest.
Image credit: Modified by gjrk from Burl (BAR 195 1988) and O’Nuallain (JRSAI 114 1984)