As Bob has probably already let you know, it is believed that John Calvert who married Esther Jones, is probably the son of a John Calvert who resided in Upper Bald Eagle twp of Mifflin County, PA during the 1780s and 1790s.The twp is now called Spring Twp in Centre County. The mother of John Calvert--who married Esther Jones--is not known.There is a notation of a Calbert woman in the 1800 census of Mifflin County.This notation is believed by some to be Wandlas Calbert, but in looking at the other notations made in the census it may represent "Widow" Calvert.The original handwriting has been gone over by someone later.
There is a Jane Calber noted in the 1810 Census of Centre county.No other Calverts are found in the census records of the county until Thomas Calvert arrives from England in the 1850s or 1860s.
In response to your Jane Mercer Calvert, it is believed that the Jane Mercer who married John Calvert was actually Jane Swayne who first married a Mercer and, later, after Mercer died, a Joseph/John Calvert.This Calvert family settled in Illinois a little later than the influx of the three Calvert brothers into the eastern Ohio Counties--starting with Belmont county.
But--, it is possible that there was another John Calvert who married a Jane Mercer.The Mercer family records are muddled as are the Calverts for the same reasons as explained below.
There is a very real problem in researching the Calvert and Mercer families.A scam was carried out in the early 1900s that tried to tie every Calvert family in the world to the Baltimore line.The Mercers were given a slightly different song and dance but the resulting damage was the same.Records from ancestors can, therefore, be muddled or out right lies given to them by these unscrupulous people.Some of the recollections could be true.I would hesitate to discard them without proper investigation.
Darryl Elliot was in Centre and Mifflin Counties trying to find records this spring.He had to terminate his research because of problems with his motor home.He believes the family is derived from the Swingate line and thus back to the Baltimores.It is possible.Segments of this Swingate line did settle in the Philidelphia area before moving on.
Two or three years ago several of us got together and hired a young man to research the records in the Centre county area.What he found make us fairly sure that John, Job, and Jacob of Belmont County were brothers and the son of a John Calvert.
It would help if we could find a will esecuted by the first John, or the transfer of lands by one or two of these three brothers to another female member of the family.Darryl was not able to find such documents. He is a good researcher, so it may be that there is nothing to find.
If anyone one wants to go together to hire a professional researcher on the subject, I would be glad to donate a little to the cause.With weddings and such coming up, it would not be much at this time.