TERRESTRIAL arthropods have a fossil record that reaches back to at least the Upper Silurian (420 million years ago). Most available data on these early land animals comes from a few sites at which abundant microarthropod remains are preserved as organic cuticle fragments. Such cuticle assemblages imply that early terrestrial ecosystems were dominated by small arthropods of the soil and litter, We describe here new impression and impression/compression fossils from the Emsian stage of New Brunsnick and Quebec, Canada, which include millipeds, arthropleurids, and a scorpion with book-lungs preserved. They suggest that surface macroarthropods were also a significant component of the land fauna.