Underwood Mary Pearl Researching Maiden Name and Her Mother S Maiden Name B Kansas 1879 1880

Underwood, Mary Pearl....researching maiden name. Married Joseph Freeman Underwood. Iowa
Mary (Pearl) born 1879-1880 in Kansas. was she adopted? She is on a census with the Pardon Smith Family in Holt County, Nebraska in 1880. Mother's name was Roxy, Roxanne...born abt 1840? Roxy's parents both died two weeks apart, possibly in the winter time. ...in one document, Mary lists her mother's birthplace as Indiana.