Your Andrew Alexander b. 1749 comes too late to be a son of the Andrew Alexander who was one of the seven brothers of Cecil Co. MD area, since that one, according to my information, was b. 1648 and d. bef 1700, and his children were Abigail b. 1677, Elias b. 1679, and Francis, all b. in Somerset Co. MD where this group was before moving up to Cecil Co.If your line comes from these seven brothers, there is a great deal of information available.They were Ulster Scots Presbyterians, by way of Donegal; their father was Rev. James Alexander b. 1634 Scotland d. 1704 Ireland, a minor historical figure in the persecution under King James II.His line goes back to William Alexander, 1st Earl of Stirling, and on back to Robert 1st (Bruce), King of Scotland.I am indebted to Joanne Brummitt Lacy for much of this information; she has been at it for fifteen years.