Ordovician

[,ɔ:dəu'viʃən;-ʃiən]

解释:

(noun.) from 500 million to 425 million years ago; conodonts and ostracods and algae and seaweeds.

卡拉校对--From WordNet

解释:

(a.) Of or pertaining to a division of the Silurian formation, corresponding in general to the Lower Silurian of most authors, exclusive of the Cambrian.

(n.) The Ordovician formation.

手打:瓦内萨