Most of the articulated crinoids and vertebrate fossils of the Guanling biota hail from a dark grey micrite at the base of the lower member's upper section.
The lower member concludes with a sequence of dark grey laminated marls incorporating conodont fossils and silty quartz grains.
[1][4] The middle member of the Xiaowa Formation is by far the thickest unit and includes thick-bedded grey limestone and marl layers interbedding with each other.
The middle member represents a deep-water environment influenced by tectonic events which disturb sediment layers and create distant turbidites that periodically supply increased clastic material.
This member represents a shallower ocean environment (likely raised by tectonic uplift) supplied with dust from terrestrial areas[1][4] The Xiaowa Formation encompasses several biostratigraphic zones.