Abstract: In the vicinity of Shanxian ,western Henan,there occurs a sequence of medium-to low-grade metamorphicclastic rocks and carbonate rocks, which was assigned by predecessors to the Archean Taihua Group or Early Pro-terozoic Xiong’er Group. Through sorting stratigraphic units,the author found that this sequence is an independentlithostratigraphic unit,lying unconformably on the Taihua Group and below the Xiong’er Group. As it occurs in theMount Fangniu area,a new lithostratigraphic unit named the Fangniushan Formation is established.This paper de-scribes the stratotype section of this formation.