Edgar and Emma Lived IN Springfield PA

Edgar and Emma lived in Springfield, PA. Erie county. They had 2 children. Lucy in 1904 and William in 1909. They are in the 1910 census, but all traces are gone by 1920. I am lost with these people. William was my grandfather, but died vey young. Lucy married(Davis) and lived in Miami.Do not know of any information on any of them.