John Lyman Clark(e) birth parents virginia 1850's

My name is Susan Clark, John Lyman was my paternal great grandfather, born in North Virginia around 1855, and died in Philadelphia Pennsylvania in 1944. John was married to Rachel Pastor, and to my knowing had 2 children, Isadora Clark, born around 1895, and Lyman Clark born Feb 9, 1900. (There may have been another daughter named Martha, I am not exactly sure)

I cannot find any information on John Lyman's birth parents, all I know that he was born in North Virginia.I have tried various ancestry sites and having no luck.Any information would be greatly appreciated.Finding John Lyman Clark's birth parents may hopefully end the mystery to many ancestry questions I am seeking.

Also I spell Clark without the E now, but there may have been an E on the end.