John and/or Diannah Usary/Ursary. etc

My gr-grandmother, Diannah (Ursary/Usery) Gregorywas the grand daughter of Michael Barnett, whose daughter (unknown) married a Usary/Ursary man in Jefferson Co., TN.Diannah was born between 1812 and 1820 and had one brother, John, born about 1814 in Jefferson Co., TN.I do not know the correct spelling of their last name as it is found spelled different ways.John married Catherine Givens in 1831 and Diannah married George Gregory in 1833, both in Jefferson Co. and were later found in the Rhea/Meigs Co., TN area.Would certainly appreciate any information regarding the names of their parents (Barnett/Ursary/Usery?)Thanks