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。
This change in plankton found in marine deposits is what marks the boundary between the Cretaceous and the Tertiary.
他说：“化石记录一再证实现代胎盘类哺乳动物的起源是在白垩纪-早第三纪分界点的时候或那之后。
“The fossil record continues to show that the origin of modern placental mammals postdates or is at the Cretaceous-Paleogene boundary, ” he said.
它说明了虱子的历史非常久，在白垩纪-早第三纪过渡期之前，而且也肯定是寄生在某种生物上的。
It says lice are old, predate the Cretaceous-Paleogene boundary, and must have been living on something.
这个有着6550万年历史的地层分离了白垩纪的化石和第三纪的化石。
This 65.5-million-year-old layer of Earth separates fossils of the Cretaceous period from those of the Tertiary period.
白垩纪至第三纪，随上覆地层增厚，断层封闭性增强。
From the Cretaceous to Tertiary, fault sealing built up with thickening of the overlying strata.
比如，白垩纪至第三纪所发生的大灭绝。当时，可能由于一颗小行星撞击地球，恐龙和众多同时代的物种都灭绝了。
An example is the KT Mass Extinction when the last dinosaur and ammonite species, among others, became extinct, perhaps as a result of an asteroid striking the Earth.
从起源上看， 被子植物的古特有属主要发生于晚白垩纪和早第三纪，地质历史上大都占有广阔的分布区；
The relic genera once occupied huge areas in North Hemisphere in the Tertiary or the late Cretaceous, while neo-endemism was mostly originated in the late Tertiary .
从起源上看， 被子植物的古特有属主要发生于晚白垩纪和早第三纪，地质历史上大都占有广阔的分布区；
The relic genera once occupied huge areas in North Hemisphere in the Tertiary or the late Cretaceous, while neo-endemism was mostly originated in the late Tertiary .
应用推荐