I have a Matilla Foulks who might well be whom you are looking for, as she is shown as marrying a McGinnis. She is the daughter of William and Elizabeth (Morgan) Foulks. William was born 10 June 1770, died 3 Sep. 1833 in Richland County, Ohio. He died in Weller in that county. Elizabeth (Betsey) was the daughter of Charles Morgan, a revolutionary war soldier who lived near Clinton, PA.
My information, whihc is my parents' old notebook, showed William's father as george Foulks, but that has been crossed out and I cannot make sense of the penciled notes.