Since Sheldon died in June 1900, the census in the part of the county where he was living, probably was taken AFTER his death.The census, where his children were taken to, after he died, was taken BEFORE the children went there.
That is the only explanation.
Did you ever get a copy of Sheldon's death certificate?It might have some important information.Like who gave the information to the person filling out the certificate.
Anyway, as I mentioned, the ONLY possibility I could find for your Sheldon Harwood was the following.
1870 York Co., VA - Nelson Twp. - Williamsburg P.O. - July 25, 1870 - page 1 6/6 Harwood, Humphrey - 37 - farmer - $300 - VA Laura - 35 - keeps house - VA Alexander - 14 - farm labor - VA Margaret - 11 - at home - VA George - 8 - VA SHELDON - 7 - VA Thomas - 3 - VA Martha - 1 - VA
1880 James City Co., VA - Jamesworn Twp. - June 14, 1880 - page 35A/358 6/6 Harwood, Humphrey - 47- farmer - VA Laura - 45 - keeps house - VA George - 20 - works on farm - VA SHELDON - 18 - works on farm - VA Elizabeth - 21 - VA Thomas - 12 - works on farm - VA Martha - 11 - VA Samuel E. - 8 - VA Tichard - 6 - VA
I tried to locate the above SHELDON HARWOOD, for the 1900 census, and he is no where to be found.Maybe he was yours.