The Nakano Formation of the Sakurae Group along Senjokei Gorge in central Shimane Prefecture consists mainly of acidic crystal tuff and acidic welded tuff．Some dikes and plutons are emplaced in the western to northern parts of the mapped area．One pluton has made a domal structure in the Sakurae Group．An arcuate fault with NNE-SSW trend is inferred at the central area．
We review the stratigraphy of the Nakano Formation and divide it into three members；the Kawado Tuff Member，the Tazu Welded Tuff Member and the Kamnamijiyama Rhyolite Member，in ascending order．