Mare Australe (the "southern sea") is a
lunar mare located in the southeastern hemisphere of the
Moon. It is 603 miles in diameter, overlapping the near and far sides of the Moon. Smooth, dark
volcanic basalt lines the bottom of the mare. The Australe basin was formed in the
Pre-Nectarian[?] epoch, while the mare material inside formed in the
Upper Imbrian[?] epoch.