Melani: There is an article in today's Louisville (Kentucky) Courier Journal (concerning violence there in 1855) that might shed some light on Sheridan's reluctance to be linked with his Irish heritage:

http://www.courier-journal.com/apps/pbcs.dll/article?AID=/20050730/NEWS01/507300373


On another note, Gerry Farrelly (a fine singer from Oldcastle, Co Meath - now living and singing in Balto., MD. USA) can document his family connection to Phil Sheridan through his late mother's side (she was a Sheridan).