“…In contrast, after the latest Tremadocian, the stromatolitebearing reefs declined markedly and only remained in the Dongzhi area, located on a marginal part of the platform (e.g., Li et al 2004b;Adachi et al 2009;Cao et al 2009) (Fig. 9). (2) Whereas the calcimicrobe Girvanella is common everywhere, Renalcis and Epiphyton are only found in the Dongzhi area (3) During the late Tremadocian to early Floian, the skeletal-dominated reefs, such as the lithistid sponge-bryozoan reefs, were limited to the Three Gorges area and its surroundings (e.g., Zhu et al 2006;Adachi et al 2011); however, the skeletal reefbuilders, such as the lithistid sponges, receptaculitids and bryozoans, expanded their habitats from the Three Gorges area, located in a central part of the platform, to the Dongzhi and Tongzi areas, forming the lithistid spongecalcimicrobial reefs (e.g., Adachi et al 2009;Cao et al 2009) (Fig. 9).…”