Abstract: The bioturbate limestone at the upper member of Hezhou Formation of Lower Carboniferous in north-ern Chao County w'as caused by Tlralassinoides sp. which produced at the semiconsolidated, but not fullylithified discontinuity surfaces. It could be attributed to Glossifungites ichnofacies which was formed in theintertidal flat environment. The features of carbonate microfacies and chemical components of the fills in the burrow systems differfrom that of the host rock. The fotmter is finely crystaline limestone mainly with crinoidal debris and containshigher clay minerals and dolomite than that of the latter. The latter is biomicrite bearing foraminifer,fusulina, molluscan and crinoidal debris. These differences imply that they were not formed in the same timeand environment. The fills were piped in the burrow systems in the next transgression after the halt of deposi-tron. The occurrence of Glossifungites ichnofacies at the uppetirtost surface of Hezhou Formation could pro-vide a new important stratigraphic information for interpreting the lacking of Laohudong Formation be-tween Huanglong Formation of Upper Carboniferous and Hezhou Formation of Lower Carboniferous herewhich prevails in southern Chao County.