upper Permian series

• 上二叠统

upper Permian series的用法和样例：

例句

1. Coal in the Upper Permian Longtan Fm in southern Poyang depression is called bark coal, because it is rich in periblinite.
   南鄱阳坳陷的上二叠统龙潭组煤层因富含树皮体而称之树皮煤。