My family history says that a William Cart of Clay County, W. Va., fathered an illegitimate daughter by one Thankful Young (my great grandmother) in 1892. Given that Thankful's mother's maiden name was also Cart--well, what can you say? The Wm Cart you mention would have been in his late 40s at the time of the girl's birth, so it calls into question whether or not it was the same William Cart. Hope this helps.