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Just so you know, I'm not local. The Tithe listing for Galbally is dated 1830 and the Griffiths Valuation for Co. Limerick was in 1850. There is a William Looby in Galbally parish in the Griffiths.for Galbally parish in Ballynamona townland. is that your William? https://www.failteromhat.com/griffiths/limerick/galbally.htm If so, likely the place name of Ahanasack was merged into the official townland of Ballynamona when townlands were standardized around 1850.