evolutional

It's difficult to decide the position of the unit in evolutional seriary of magma.

该单元在岩浆演化序列中所处的位1难以确定。

The new framework, comprising a pre-trilobite series and three trilobite-dominated series, reflects the major evolutional stages of the life on Earth during Cambrian Period.

新的划分方案包括1“叶统”和3“叶优势统”，反映了寒命发展的主要阶段。