This change in plankton found in marine deposits is what marks the boundary between the Cretaceous and the Tertiary.
海洋沉积物中浮游生物的这种变化标志着白垩纪和第三纪的分界线。
词典释义:
n. 白垩纪-第三纪边界;白垩纪-第三纪界线;白垩纪-第三纪分界线
This change in plankton found in marine deposits is what marks the boundary between the Cretaceous and the Tertiary.
海洋沉积物中浮游生物的这种变化标志着白垩纪和第三纪的分界线。