Geologic map of the Wilhelm Quadrangle of the Moon

The Wilhelm quadrangle lies along a mare highlands boundary west of the crater Tycho, southeast of Mare Humorum, and southwest of Mare Numbium. The outer scarp of the Orientale basin is 1200 km to the West-Northwest. The quadrangle is characterized by pitted and mantled appearing terra, which in the north is interrupted by patches of mare and in the south by several large pre-Imbrian craters. Most of the mare material occupies angular massif bounded depressions which are approximately concentric and radial to the basins that contain Mare Humorum and Mare Numbium. Most of the large craters are either partly subdued (Wurzelbauer, Montanari), the degree of subdual apparently resulting from a mantle of terra material of varying thickness. Only Longomontanus, though heavily pitted, seems relatively unmantled; it lies on the western margin of a "marco-crater province" of conspicuous large craters that extends southeast and east of the quadrangle (Hackman and Mason, 1961).