I've not tried to identify the parents of John and Hannah Hill Jarvis [not gotten that far back yet] but Don Norman, who wrote a good deal of history on the families in the Hacker's Creek area of [West] Virginia makes this observation:
"One source lists John as possibly a son or step son of Daniel Jarvis, who was born about 1650 in London, England and married a Mrs. Jane Jarvis in that area about 1673. This is not likely, since Daniel would have been about 70 years old when John was born in 1720 and Jane would have been nearly as old."http://hackerscreek.com/norman/JARVIS/JOHN.htm
Pls note, if you refer to this source, that it contains several errors about the John Jarvis line - in fact combining two separate men into one composite.