Looking for Ribble of Virginia

I'm interested in finding information of my grandmother who I did not know.
Her name was Margertha Antoinette Ribble; DOB 11/20/1890, Wytheville, Wythe County, Virginia;DOD 7/18/1971. The father's name was Dr. William Henry Ribble, Jr.; mother's Margertha Antoinette Heuser.
Dr. Ribble said that she adopted a daughter. Does anyone have information on her daughter
"Margretha Louise Peggy Ribble"? We feel strongly she had an affair and did not tell people the
truth. My mother has since died.