Barry,
Research in Ireland in the 1700s is notoriously difficult due to the general lack of records. Very very few churches have any records for the 1700s and so if the family were from a rural area, then sadly it’s quite likely that there are no surviving records of them at all.
You haven’t said what denomination(s) the Gourley & McNeal/McNeill families were. Do you know? That’s pretty essential information. (I looked in the 1901 census for Co. Derry and the majority of Gourleys were Presbyterian or Church of Ireland. One or two RC families).
There are several trees on Ancestry which have this family. One (Kelly’s Shade) gives George’s parents as William Gourley (1732 – 1806( and T. Lees (1736 to an unknown date). No source is given. And George is named as William George. That tree also has the information that George married Rosanna McNeal (1774 – 1853) in Loop, Indiana, Pennsylvania in 1802. However the tree also says that he only arrived in the USA in 1804 and that the couple’s first child (Thomas) was born back in Londonderry in 1805. So you’d have to scratch your head and wonder whether that’s all quite correct. But you might want to contact the owners of all those trees to see what evidence and information they have.
Kelly’s Shade tree also says William George Gourley (1769) was born in Londonderry, Londonderry. To me that means he was born in the city, as opposed to the rural county. If so, the records there are a bit better than the rest of the county. The Church of Ireland records start in 1642, 1st Derry Presbyterian start in 1815 and the RC in 1823. So if the Gourley family was Church of Ireland then you might find all the children’s baptisms, if Presbyterian you might find George baptised in 1816 but if RC you won’t find them at all. Copies of the Church of Ireland and Presbyterian records are in PRONI (the public record office) in Belfast.
