Geologic map of the Mare Undarum Quadrangle of the Moon

The map area contains two mare provinces, one terra province, and one province of mixed mare and terra. The maria are the semicircular southern half of Mare Crisium and the northeast sector of Mare Fecunditatis. The massive belt of terra that arcs across the quadrangle between these maria is the south rim of the Crisium multiringed basin; its southwest part is probably superposed on an older, originally similar, accurate rim of the Fecunditatis basin. The fourth province, in the southeast corner, includes small irregular maria such as Mare Undarum and Mare Spumans and intervening peninsulas and islands of terra.