Lacus Mortis 45.0°N, 27.0°E

The ‘Sea of Death’ fills an extensively eroded large complex crater of about 150 km diameter, of which, fundamentally, only the western crater wall remains. The lava covers an area of c. 210 000 km2 and lies to the south of the eastern end of Mare Frigoris.

Mason 42.6°N, 30.5°E

Plana 42.2°N, 28.2°E

Lying south of Bürg is the overlapping pair of craters Mason and Plana (oriented east-west). Both craters are lava-flooded. Mason, with dimensions of 33 × 43 km, is a significantly elliptical crater. Plana has a central peak and a diameter of 44 km. Both craters seem partially ruined, and on both crater floors craterlets are visible in large telescopes.

Bürg 45.0°N, 28.2°E

Bürg is a prominent young crater (diameter 39 km) with a sharp-edged crater wall, that towers above the crater floor by about 2.2 km. The crater lies in the middle of a lava flow that was produced significantly earlier. Bürg has been dated to the Copernican period on the lunar timescale and in certainly one of the youngest of the larger craters on the nearside.

Bürg has a dominant central peak and terraced inner crater walls with many deep cracks and breaks. The ejecta from the impact lies in two masses to the north and – in a broad fan – to the south of the crater (somewhat similar to a mare wrinkle ridge).