Marius is a lunar crater located on the Oceanus Procellarum. The surface to the west and north of this crater contains a large number of lunar domes spread across an area over a hundred kilometers in diameter that may be of volcanic origin dubbed the Marius Hills. These domes, if volcanic, may have been formed by magma that is fairly more viscous than the volcanic material that formed the basaltic lunar maria. The nearest named crater feature is Reiner to the southwest. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On the Moon they are named after deceased scientists, polar explorers, astronauts or cosmonauts.
