cretaceous是什么意思音标:英 [krɪ'teɪʃəs]美 [krɪ'teɪʃəs]

a. 白垩系的, 白垩纪的
n. 白垩纪, 白垩系

n. from 135 milpon to 63 milpon years ago; end of the age of reptiles; appearance of modern insects and flowering plants
a. abounding in chalk
a. of or relating to or denoting the third period of the Mesozoic era