The Carraig á Mhaistin stone (transl. Bully Rock) is a megalithic tomb located in Cork harbour. It was previously believed to have been an 18th-century folly, built by Murrough O'Brien, 1st Marquess of Thomond, like the nearby Siddons Tower folly.^[1]

The monument was first reported by antiquarian John Windele after an 1860 visit to the area. A man named Dr. Wise had the capstone raised from where it had fallen.^[2]

The tomb is nearly submerged at the high tide mark, as is the accompanying cairn. The tomb is made of three upright stones largely covered in seaweed and a capstone. It faces east.

• R. Welch (Sep 1907). "Further Note on the Rostellan Cromleac". The Irish Naturalist. 16 (9): 267–269. JSTOR 25523124.
• Cott, Grace M., Marcel AK Jansen, and Deborah V. Chapman. "Salt-Marshes on peat substrate: where blanket bogs encounter the marine environment." Journal of Coastal Research 28.3 (2012): 700-706. " In other parts of the country, O'Kelly (1945) referred to the Rostellan Dolmen in county Cork, estimated age 4000 BP, which becomes partially submerged at high tide. " doi:10.2112/JCOASTRES-D-11-00108.1
• Daniel, Glyn E. (Sep 1952). "Prehistoric Ireland". Irish Historical Studies. 8 (30): 164–168. doi:10.1017/S0021121400027383. JSTOR 30004781. S2CID 163855351. (review of Prehistoric Ireland by Joseph Raftery)
• Viney, Michael (2014). Ireland: A Smithsonian Natural History. Smithsonian Institution. ISBN 9781588344243. Robert Lloyd Praeger with his wife, Hedwig, standing on Rostellan Cromlech, a megalithic tomb, during a fieldclub conference in 1907

• "Rostellan Dolmen - Ring of Cork". www.ringofcork.ie.
• "Rostellan Portal Tomb". irishstones.org.
• "Rostellan Dolmen". Voices from the Dawn. 3 August 2010. (virtual view)

• Killanin, Michael Morris Baron (1976) [1962]. The Shell guide to Ireland (2d, revised and reset ed.). Norton.