Ancestors for David March

I am researching my Pennsylvania March ancestors for a book about my childhood.The earliest March ancestor that I can trace is a David March (Mertz) who lived in Wellsville, PA.His wife’s name is believed to be Margareda (Hess).David was born in 1834 and died in 1890.Children are: Levi A., Adam U., George L., Mary C., Magaret, David Robert, and John H.

Any information is appreciated. Other published books by Abe F. March are:
“To Beirut and Back – An American in the Middle East”
“They Plotted Revenge Against America”
“Journey Into The Past”