I, too, am searching for a Black family with origins in Ballylin, County Donegal, Ireland. Does this information mean anything to you?
"BLACK, Samuel, of Boston, Mass.; from Ballylin, Donegal, Ireland; mariner; m. Elizabeth Fulton; d. before 1752.—Goldthwaite Records, Ms. Boston Athenaeum." (Sorry, no further info.)
I've also found connections between William Murray (d 1760) of the Manor of Mooreland, Philadelphia Co, PA; David Fulton, a miller, who witnessed William Murray's Will; Mary Murray of Boston (who bought a portrait of William Murray); William and Elizabeth (Fulton) Standley of the Manor of Moreland (and their son, Valentine Standley); James Fullton, an import/export merchant in Philadelphia with partners in Londonderry; and Andrew Black of Boston. All of these records are for the period 1748-1770.
Between 1750 and 1770, brothers John and Thomas Fulton were living at Rathmelton, County Donegal, Ireland. John Fulton and partner Ephraim Campbell had offices in Londonderry and represented James Fullton of Philadelphia. The Fultons shipped goods and passengers between Londonderry and Philadelphia.
Have you ever run across the Fulton family in your Black research?