There are generally thick bedded conglomerate at the base.The dominant lithologies of the top are gray-dark carbonaceous shale interbedded with lenticular bodies of coal smit.

• 沉积二滩组时期，研究区处于泥坪、混合坪、不稳定碳酸盐合地及潮坪沼泽等环境，代表一次较大的海进海退过程。