My husband's family comes from York. His grandfather, Issac A. left in 1852. Isaac's brother, David remained in York. David's son, Gabriel, had a store in York at 153 S. Queen St. that he operated for 45years. As to the son Adam, who is listed as John's first child,I am assuming he was from a first wife that I know nothing about. Also, Elizabeth, John's wife was born about 1790...we do not have an exact date. We have been back to York twice (we live in KS)and have been to the Marks cemetery and farm down Betty Washington Road and I know of the John and Joseph Marks who had the farm there, but have not been able to match my John to the one on the farm. Do you know how old Jacob Erhart was in 1800? As I posted, I am assuming that Elizabeth is his daughter. Thank you for your interest. Would be delighted to hear from you again.