I believe this is Penelope with her father & mother, indexed as "Row"
1850Harpers Ferry, Jefferson, VA
John M Row48VA Mary E23VA Charles C10 PENELOPE A7 Robert E5 William35 Harrietta Monroe23
Suspect that William is a brother.....perhaps some research on him and on Charles might turn up something.I couldn't find a marriage for John so luck with a maiden name for Mary.
Mary is widowed with the children you mention in 1860 Bolivar, Jefferson.If you go to findagrave.com there is a John Rowe buried at Fairview Lutheran Cemetery in Bolivar with a picture of the stone.The birth year doesn't quite match but the death year of 1858 would fit since James was b about 1857 & Mary is widowed by 1860.