High Quality Content by WIKIPEDIA articles! Montes Caucasus is a rugged range of mountains in the northeastern part of the Moon. It begins at a gap of level surface that joins the Mare Imbrium to the west with the Mare Serenitatis to the east, and extends in an irregular band to the north-northeast to the western side of the prominent crater Eudoxus. The range forms the northwestern boundary of the Mare Serenitatis. It forms a continuation of the Montes Apenninus range to the southwest.