Stromatolites are representative of the microbial carbonates, and are buildups of “algae-mats” (microbial mats) in the rock record. The stromatolitic biostrome in the lower part of the Furongian Fengshan Formation at the Xiaweidian section in the western suburb of Beijing is marked by a bed of stromatolitic limestones with the thickness from 2 to 3 m. Macroscopically, this stromatolitic biostrome is made up of column stromatolites. Microscopically, this stromatolitic biostrome is mainly composed of dense micrites and wackstones, which demonstrate that the stromatolite is characteristic of the micrite facies. There are various categories of carbonate grains, such as benthic oolites, oncolites and clots within column stromatolites, which reflects the diversity of the biogenic carbonate grain within microbial mats. Further, trilobite skeletal clasts within dense micrites represent the strong binding during the growth of the stromatolite, and pyrite crystals within dense micrites making up of the column stromatolite indirectly demonstrate that the formation of dense micrites is genetically relative to heterotrophy-bateria activities. Therefore, the stromatolitic biostrome in the lower part of the Furongian Fengshan Formation becomes a representatively sedimentological phenomenon in a special geological period that is marked by a particular “stormy sea with the scarcity of metazoan skeletons”. Furthermore, this stromatolitic biostrome is a typical example of microbial reef forming in the relative deep-water setting that is absent of the reef-building metazoans in the early period of the Early Paleozoic and a particular rock record for the understanding of the diversity of the biogenic carbonate grain within microbial mats.