頁岩砂岩
公烏素組為薄層灰岩、頁岩、砂岩互層。含筆石:Amplexograptus gansuensis 帶。層位與Climacograptus wilsoni帶大致相當。系深水陸棚沉積。與下伏拉什仲組、上覆蛇山組均為整合接觸。厚...