Ordovician strata的用法和樣例：
例句
- The Ordovician structure in the middle and east part of the Erdos Basin is a gently west-dipped large monocline.
鄂爾多斯盆地的中東部奧陶系今構造為一平緩的西傾大單斜。 - Finally the stratigraphic ages and correlation of the Ordovician lithostratigraphic units in the study area are discussed.
筆者認為，申扎組應被廢棄，德悟卡下組底界應作修訂，并對該地區奧陶系巖石地層單位進(jìn)行了簡(jiǎn)要的時(shí)代討論和對比。
