Asiamerica

This is a rarely used name for western North America during the Late Cretaceous and Paleogene. The "asia" part of the name comes from the fact that the region was intermittently in contact with the North China terrane during this period, leading to a significant degree of similarity in biota. For part of this period, western North America was separated from eastern North America by the broad, but shallow, Western Interior Sea. Consequently, North American organisms were, at times, more closely related to their Mongolian counterparts than to their more distant cousins along the Atlantic coast. The region was home to many unique dinosaurs and archaic mammals.