Abstract: Through a study of the petrography. petrology and structural geology, the "meta-acid volcanic rocks or metapotassic rhyolite" over the core region of the Hujiayu-Shangyupo anticline are considered to he hypahyssal felsitic porphyry bodies intruded in the middle-late Zhongtiaoan stage and cannot be regarded as the same stratigraphic unit as meta-acid volcanie rocks of the Jiangxian Group in the Tongknangyu area in the northern part of the area.