11O'Donovan, John, Eugene O'Curry, Thomas O'Connor, and George Petrie. Letters Containing Information Relative to the Antiquities of the County of Westmeath Collected during the Progress of the Ordnance Survey, 1837,. Ed. Michael O'Flanaghan. Bray. 1927, p. 41.
To this, Roseanne Schot adds: "Surprisingly, O'Donovan failed to take notice of the circular earthen bank that surrounds the stone (although the enclosure is shown on the 1838 Ordnance Survey map)...." ( Schot, Roseanne. “Schot, Roseanne. “Uisneach Midi a Medón Érenn: A Prehistoric ‘Cult’ Centre and ‘Royal Site’ in Co. Westmeath.” The Journal of Irish Archaeology 15 (2006): 45-6. http://www.jstor.org/stable/20650850.)