Two main glacial epochs affected both areas during the last 100 million years of Precambrian times. 在前寒武纪的最后1亿年中,两个主要的冰川时期对两个地区都产生了影响。
The most ancient parts of the continental crust are 4000 million years old. 大陆地壳最古老的部分有40亿年历史。
Twenty million years ago, Idaho was populated by dense primordial forest. 2,000万年前,爱达荷州到处都是茂密的原始森林。
Twenty million years ago, Idaho was not the arid place it is now. Rather, it was warm and damp, populated by dense primordial forest 2,000万年前,爱达荷州并不像现在这样干旱。相反,那时的爱达荷州温暖潮湿,有大片的原始森林。
Leakey discovered the skull of a woman who lived a million years ago. 利基发现了一个生活在一百万年(MY)前的女人头盖骨。