Cladoselache is a genus of extinct shark. It appeared in the Devonian period.This primitive shark grew to be up to 6 feet (1.8 m) long and roamed the oceans of North America. It is known to be a fast moving and fairly agile predator due to its streamline body and deep forked tail. Cladoselache is one of the best known of the early sharks in part to the well preserved fossils that were discovered on the 'Cleveland Shale' on the south shore of Lake Erie. In addition to the skeleton, the fossils were so well-preserved that they included traces of skin, muscle fibres, and internal organs, such as the kidneys.