paleozoic

(brit. Palaeozoic) adj. Of an era of geological time marked by the appearance of plants and animals, esp. Invertebrates. n. This era. [greek zoion animal]

a. Of or pertaining to, or designating, the older division of geological time during which life is known to have existed, including the Silurian, Devonian, and Carboniferous ages, and also to the life or rocks of those ages. See Chart of Geology.