small asymmetric ripple marks with bifurcation (BRM; were found from the C-section of turbidite with the Bouma sequence in the eastern slope of the Guilin carbonate platform. The BRM are 7. 5-8. 0 cm in wavelength, 0. 5-0. 8 cm in wave-height, 5. 0-7. 0 cm in the length of stoss side and 2. 5-4. 0 cm in the length of lee side. The ripple indices are 15-10 and the ripple symmetry indices are 2. 0-1. 8. The lee sides slope eastwards. The crests of the BRM are rounded and slightly sinuous and are apparently of bifurcation. The BRM were suggested to be formed under the circumstances of the lower regime with following the lowering of the turbidity-current velocity, the transformation density currents into tractive currents and the superimposition of progradational storm-wave. Based on the characteristics of the BRM and host strata, the maximum or limit water-depth of the Yangsuo carbonate basin containing BRM were estimated to be about 100 m or less than 200 m. The estimations may represent the quantitative water-depth of the Devonian carbonate basin containing the calcareous turbidite and conodont fauna, and may be the water depth boundary between the marine deep fauna almost not influenced and the marine shallow water fauna significantly influenced during the Devonian Frasnian - Famennian transitional events.