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.

分方包括1“叶虫统”和3“叶虫优势统”，反映了寒武纪生命发展主要阶段。