The early Cretaceous fossils that we find in Maryland are preserved in sandstones and clay-stones.

我们在马里兰发现的白垩纪早期化石保存在砂岩和粘土岩中。

To find such living fossils from as far back as the Cretaceous is extraordinary.

能发现白垩纪的活化石是非同了不起的。

It lived in coastal wetlands more than 66 million years ago during Earth's Cretaceous Period.

它生活在6600多万年前地球白垩纪时期的沿海湿地中。

The oldest-known ant fossil dates back about 100 million years to the Cretaceous Period.

已知的最古老的蚂蚁化石可以追溯到大约1亿年前的白垩纪时期。

Castillo said during the Creataceous, marine turtles had increased body sizes.

卡蒂略说，在白垩纪时期，海龟的体型增大了。

Predators of Cretaceous are gigantic by our standard.

在我们看来白垩纪的食肉动物都是巨大的。

All these Cretaceous plant eaters, with their complicated apparatus, they're all much more sophisticated.

所有些白垩纪的食草动物都有其复杂的防御器官，它们都是很高级的生物。

That happened 66m years ago, at the end of the Cretaceous period.

一切就发生在6600万年前的白垩纪末期。

It lived about 72 million years ago during a period of time called the Cretaceous Period.

它生活在大约7200万年前的白垩纪时期。

Quetzalcoatlus would make all other animals in the Late Cretaceous stare.

披羽蛇翼龙能让白垩纪晚期的其他动物汗毛倒立。

Over the next 90 million years, a new era called the Cretaceous period dawned.

在接下来的九千万年里，开始了一个叫做白垩纪的新时期。

That is fair enough. Such landscapes were common during the beasts' heydays, the Jurassic and Cretaceous periods.

很合理，因为样的景观在侏罗纪和白垩纪的野兽鼎盛时期很常见。

During the Cretaceous period, 140 million years ago, this dinosaur sported a neck of dangerous looking spines.

在一亿四千万年前的白垩纪，种恐龙的脖子上长着看起来很危险的刺。

It was lightweight and lived during the Cretaceous Period, about 75 million to 81 million years ago.

它的重量很轻，生活在大约7500万到8100万年前的白垩纪时期。

There were different diving birds during the Cretaceous, including North America's Hesperornis, which reached about 1.8 meters long.

白垩纪有不同的潜鸟，包括北美的长翅鸟，它长达1。8米左右。

The earliest known bird, Archaeopteryx, lived during the Jurassic, the period before the Cretaceous.

人类所熟知的最古老鸟类始祖鸟生活在白垩纪时期之前的侏罗纪时期。

Well, Edmontosaurus was sort of the Wildebeest of the Cretaceous plains.

埃德蒙顿龙就好像是白垩纪平原上的牛羚。

The findings suggest large sizes in marine turtles developed independently in separate Cretaceous lineages in North America and Europe.

研究结果表明，在北美和欧洲不同的白垩纪谱系中，体型较大的海龟独立发育。

When finished they found that they had more than tripled the global total of dinosaur fossils from the late Cretaceous.

当工作结束的时候，他们发现自己已——为颗行星——把白垩纪末期的恐龙化石增加了两倍多。

The best-documented such impact took place 65 million years ago at the end of the Cretaceous period of geological history.

记载最完整的种灾难曾发生在6500万年前，在地质历史阶段的白垩纪末期。