Hi Chelsea, William Henry Clay died in 1877, leaving Mary Ann (Hargreaves) widowed, with their 5 children. Mary Ann married Henry Blanchard in 1880 and young William Henry Blanchard appears very early in 1881, just in time to be picked up in the census.
Her children are recorded under their father's name, but she and her new child under her new husband's name. Sadly, young William Henry, named after her dead husband, died a year later in 1882.
PeterB