Geological Chronicle
Lambert is a lunar impact crater measuring 30.12 kilometers in diameter on the southern half of the Mare Imbrium basin. Dating to the Eratosthenian age, the crater occupies an isolated position on the mare, lying east and somewhat south of Timocharis and north of the smaller crater Pytheas.
The crater features an outer rampart, terraced inner walls, and a rough interior with an albedo comparable to its surroundings. Rather than a central peak, a small craterlet lies at the midpoint of the interior.
Just south of the ramparts lies the lava-covered rim of Lambert R, a ghost crater larger than Lambert that is almost completely covered by the mare. The submerged feature is difficult to detect except when the Sun is at a very low angle, casting long shadows.