The Alexanders migrated from the Wedge area where PA, MD, and DE meet. The Alexanders lived on both side of the MD/PA state line in Cecil Co, MD, and Chester Co, PA, and possibly Lancaster Co, PA.
They attended and served as elders The Rock Church, now located in MD, but formerly in PA. They were residing in this area while the border was in dispute, hence you will find records in both PA and MD. The Cecil Co, MD, Historical Society has considerable information about them. They also figure in the History of the Rock Church, a copy of which is at the Society, and in Johnston's History of Cecil County Maryland which you can obtain through interlibrary loan. I especially recommend Johnston's history for understanding the area and its history.
I don't recollect seeing the Patterson name, but I wasn't looking for it either. I have noticed some Rosses in this area, but I have not yet researched them. I am seeking Rachel Ross, third wife of John McClatchey -- they were m. in Ireland c. 1746, and migrated to North Carolina c. 1755. John had one child, (William) Hamilton McClatchey Sr, by his previous wife, Mary Hamilton. It is presumed that this family, like most Scotch-Irish, landed at one of the Delaware River ports and received aid and guidance from the local Presbyterian churches in the area (of which Rock was one. Others include Pencader and Head of Christiana/White Clay Creek). I have checked the Rock but not the other records. Alas, the Church records burned in 1900, so the history and grave markers are pretty much the only remaining records for The Rock.
My theory is that John McClatchey came over with her family, the Rosses, who later migrated to Mecklenberg Co, NC, and from there into York District, SC (just below the NC/SC state line.)
Beau Bowen P O Box 1118 Elkton, MD, 21922-1118 Beau@IXImd.com