Microbial reefs containing archaeocyaths, up to 1.5 m thick, are composed of massive to lenticular thrombolites with densely distributed, millimeter- to centimeter-scale darker mesoclots and rare archaeocyaths. These microbial reefs are enclosed by wackestone–packstone, intraclast packstone– grainstone, ooid packstone–grainstone, calcareous shale, and
fine sandstone. The thrombolites are composed mainly of Girvanella, micritic
clumps, and subordinate Epiphyton.