DARRIWILIAN STAGE

division of geologic time of the Ordovician period in Australia and, to some extent, New Zealand (the Ordovician period lasted from 505 million to 438 million years ago). The Darriwilian is younger than the Yapeenian Stage but older than the Gisbornian and is distinguished by the presence of a graptolite fossil fauna composed of the genus Glyptograptus and several species of the genus Diplograptus. Darriwilian faunas evidence closer affinities with fossil assemblages in North America than with those from Europe.