白垩系

例句：

1. 1. The dinosaurs lived during the Cretaceous period, which is known as the Age of Dinosaurs.
   恐龙生活在白垩纪时期，也就是恐龙时代。
2. 2. The discovery of a new species of bird in the fossil record has led to speculation about its originsin the Cretaceous era.
   在化石记录中发现一种新的鸟类物种，引发了人们对于其起源是否发生在白垩纪时代的猜测。
3. 3. The geological formations found in the Cretaceous period are often referred to as the "White Craton" or "Cretaceous Supercontinent."
   在白垩纪时期发现的地质构造通常被称为“白垩纪超大陆”或“古生代超级大陆”。