Paul_Mc I believe your Elizabeth Morgan, would be the sister of my great great grandmother Margaret Morgan. I just in past day found proof that they were sisters from the 1851 census.
I have parents as Michael and Catharine / Catherine Morgan (nee McMahon), siblings I have found are Elizabeth, Biddy (Bridget I am guessing), Elizabeth, Thomas and Mary. In 1851 census Catharine is listed as Widow Morgan, youngest child is 5, so Michael must have died between 1845 and 1851. All children are listed as being born in Ireland. I found Elizabeth's marriage cert which stated Derrynoose as parish in Ireland.