lower Ordovician series

• 下奥陶统

lower Ordovician series的用法和样例：

例句

1. The Lower Ordovician organic reefs were first identified in Huanghuachang of the eastern Yangtze Gorge by the authors.
   首次发现峡东下奥陶统生物礁。
2. Shimen Hunan realgar deposit controlled by both dolomite of lower Cambrian Luoshanguao Group, lower Ordovician limestone and fault.
   湖南石门雄黄矿床受寒武系下统娄山关群白云岩和下奥陶统灰岩以及断裂构造的双重控制。