Essex County, Virginia was not formed until 1692. It was formed from the "Old Rappahannock", of which I am still trying to learn about. Therefore, William was not born in Essex unless he was born a few years later. Old Rappahannock had 4 divisions of parish's: North Farnham, South Farnham, Sittenburne Parish, and St. Mary's Parish.
(Research):Source Call No: 1395784; Batch F847075; William Daniel b abt 1677.
Other Entries at IGI:
William b abt 1637 (not likely since Moses was b after 1712)
William married Sarah abt 1663 (not likely since Moses was b after 1712)
William b before 1650 (possible, but only 1 or 2 years earlier in order to have a child b after 1712)
William married Sarah abt 1673 (not likely...same reason)
All of the above are listed as being married to Sarah Williams. I'm not sure if there was another William Daniel and another Sarah Williams, but these are NOT possibilities for this particular William and Sarah. Their approximate birth years and marriage year, as well as the birth of their son, do not coincide.
Pedigree Resource Fil at www.familysearch.com: William Daniel was b 1674