Geologic map of the Maurolycus Quadrangle of the Moon

The Maurolycus quadrangle, located in the southeastern highlands, includes densely to moderately cratered terrain with many craters larger than 45 km in rim crest diameter. Several appear to be ancient and may be among the most primitive discernable features on the lunar surface. Major stratigraphic units consist of the Janssen Formation, hummocky terra and pitted plains materials, and extensive clusters of bowl-shaped craters. Two of these units, hummocky terra and pitted plains, are probably volcanic whereas the Janssen Formation and bowl-shaped craters appear to have been formed by ejecta from the multi-ringed Nectaris and Imbrium basins outside the quadrangle.