Simon and Margaret Jones are the Grandparents of Simon J. Evans. They are listed as his grandparents on the 1871 Wales Census, but his parents do not appear in the household. Additionally, there are no adults with the surname Evans in the home. Simon and Margaret had at least eleven children, and I assume one of the older daughters that do not appear on the 1871 census, but on earlier censuses is Simon J.'s Mother. I believe it is either Mary or Elizabeth but have no evidence. The matter is complicated by the fact that the names Evans and Jones are incredibly common in Llanwenog, and the records are sketchy. I will continue to look but achieving a level of certainty that makes me comfortable with the result looks impossible without a trip to Wales.
Grandpa Simon was born in Llanwenog in 1785. Margaret was his second wife, born in 1809. They were married Oct 27, 1835 and resided in Llanwenog at Esgerlygoer (street and possibly name of the house) until his death on May 4, 1870, and her death Aug 8, 1871. They are listed as farmers but I know little else about them. I would estimate a 90% certainty that Simon and Margaret are part of our family tree. Without 100% certainty I don't anticipate trying to go back further in that family line.
Relationship key:
My wife ---> Her father ---> Sarah H. Evans ---> Simon J. Evans ---> Unknown mother (Jones) ---> Simon and Margaret Jones