1820 Wythe Co., VA census: George Cress, aged 26-45yrs with wife aged 26-45yrs, 4 males <10yrs (James, Henry, Andrew, Geo Wash.); 1 male 10-16 (David); 1 male 16-26 (who? brother Joshua?); 1 female 10-16 (Nancy or Sarah Jane?). (SV-209 & 404 pg 59, SV-578 & SV-579 & SV-1665)
Did he die before 1830? If so, this would explain why 8 sons born show up as only 7 boys in the family on the 1830 census.