Paleogene
adjective geology US specialized (also mainly UK Palaeogene) uk/ˈpæl.i.ə.dʒiːn/ us/ˈpeɪ.li.oʊ.dʒiːn/
古第三纪的（迄今6600万至2300万年前）
from or referring to the period of time between about 66 and 23 million years ago, in which many insects, mammals, and birds appeared
the Paleogene period 古第三纪
Paleogene flora and fauna 古第三纪动植物
the Paleogene
noun [ S ]
古第三纪
the Paleogene period