These dome-shaped microbialites grew directly on skeletal packstones and grainstones with abundant oncoids. Laterally, the massive microbial boundstone grades into surrounding bioclastic limestones. The microbial reefs are mainly composed of cylindrical columnar stromatolites (8- 35 cm wide and 30-105 cm high), with a distinct laminar texture present over the weathered surfaces. Several stromatolites usually occur alongside each other and are packed together, creating a frame-like cluster structure. Interspaces between stromatolites are often filled with Calathium. lithistid sponge-microbial bafflelbindstones that generally lack recognizable lamination and are characterized by in situ sponges