This looks like the family in 1861
King Street, Castle Douglas
869 ED 1 Household No. 26
John Williamson, 34, Horse Breaker, b. Tynron
Margaret, 36, b. New Abbey
Isabella, 17, b. New Abbey
John, 7, b. Castle Douglas
Thomas Easton, Grandson, 1, b. Castle Douglas
James Cornelia, 26,servant, b. Buittle
I'm thinking that Thomas Easton is probably the Thomas Williamson in the 1871.
Gadget