adj.白垩的；白垩纪的
n.白垩纪；白垩系
The story takes place 6500 years ago in the late Cretaceous period. 故事发生在6500万年前的白垩纪晚期。
From the Cretaceous, Tarim basin began the new evolutional stage of foreland basin. 从白垩纪初期开始
