cretaceous period

基本解释

The prints are believed to have been made during the Cretaceous period of the Mesozoic Era, Kim said in a statement.
这些足迹被认为是在中生代白垩纪时期由当时鸟类留下的。
The temperature drop during the Cretaceous period would almost certainly have wiped out an 'abundance' of the world's dinosaurs.
曾经称霸地球显赫一时的恐龙，在白垩纪时代的这次温度巨变中，似乎全都灭绝了。
The assembled family tree shows that lice started to radiate into new species well before the end of the Cretaceous period, Dr. Smith and his colleagues report in the current issue of Biology Letters.
史密斯博士和他同事在《生物学快报》上发文指出，建立起的系统树表明在白垩纪末期之前虱子早就开始进化出不同的新物种。

These creatures lived more than sixty-five million years ago, during Earth's late Cretaceous period.
Scientists say it formed when high sea levels flooded the middle of North America, splitting the continent in two for millions of years during the late Cretaceous period.
The Tyrannosaurus lived in North America during the late Cretaceous Period.

My piece is set in the late Cretaceous period, 65 million years ago (give or take a few).
FORBES: Prototyping The Distant Future