在这一系列周期性物种灭绝事件里，白垩纪晚期恐龙和菊石的灭绝仅仅是其中一个比较严重的事件。
The late Cretaceous extinction of the dinosaurs and ammonoids was just one of the more drastic in a whole series of such recurrent extinction episodes.
无齿翼龙生活在6000万年前，这个时候是白垩纪晚期。
Pteranodons lived 60 million years ago. That time was called the late Cretaceous period.
鸟是一种已经灭绝的不会飞翔的水鸟，生活在白垩纪晚期。
Hesperornis is an extinct genus of flightless aquatic birds that lived during the Late Cretaceous.
Hutchinson说，这些古老的排水系统是在白垩纪晚期为了应付潮湿的气候而被想到的，它们已经是这样的久远。
"The ancient drainage systems are thought to have originated in the wet climate of the late Cretaceous, they are that old," Hutchinson said.
Santee海岸储藏岩心是从加州南部的查尔斯顿的545英尺深的钻井中采集的，代表白垩纪晚期、古新世、始新世和第四纪的沉积物。
The Santee Coastal Reserve core, a 545 ft deep borehole in northeastern Charleston County, South Carolina, recovered sediments of Late Cretaceous, Paleocene, Eocene, and Quaternary age.
然而，查特基博士的说法引发了疑问：为什么全球白垩纪晚期岩石中含有冲击石英和铱的喷发物地层只有一层？ 答案或许是，两次撞击是在同时发生的。
This story, though, raises the question of why there is but a single ejecta layer of iridium and shocked quartz in late Cretaceous rocks around the world.
这意味着我们有关巴拉乌尔龙的记录限定于白垩纪的晚期的晚期。
That means that our record of Balaur is restricted to the very end of the Cretaceous.
现今的磷灰石裂变径迹年龄格局基本上受控于白垩纪的快速抬升冷却事件，但最后为晚期活动断裂所定格。
The present AFT age pattern is, therefore, basically controlled by the Cretaceous rapid cooling event but finally shaped through active faults.
侏罗纪晚期和白垩纪早期任一种食肉恐龙，形似霸王龙但体型较小。
Any of various carnivorous dinosaurs of the late Jurassic and early Cretaceous Periods, similar to but smaller than the tyrannosaur.
侏罗纪晚期和白垩纪早期任一种食肉恐龙，形似霸王龙但体型较小。
Any of various carnivorous dinosaurs of the late Jurassic and early Cretaceous Periods, similar to but smaller than the tyrannosaur.
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