原级：epoch
1. 世：每代分若干纪(Periods),每纪又分若干世(Epochs)(表4-1). 相对应的地层:界-系-统-层. 对应于地质年代为代-纪-世-期. 关于各地层的年龄,过去只能根据地层的厚薄,按照地层每增厚1m约需若干年来计算,或首先估算地球的年龄,再按地层厚薄,
1. epochs什么意思
1. " We're able to draw together these three distant epochs and see how our models compare, " Colless told AFP.
2. 911查询·英语单词
2. Other paleontologists said they were not surprised that the region had yielded more discoveries from earlier epochs in the time of dinosaurs.