(LAC-11) Geologic map of the J. Herschel quadrangle of the moon

Lunar surface materials are classed into units on the basis of visual observations and data from telescopic and Lunar Orbiter photographs. Each unit has a distinctive range of physical characteristics, such as topography and albedo (reflectivity under full-Moon illumination), and is considered analogous to a terrestrial rock-stratigraphic formation.  These characteristics rather than lithologic properties must, of necessity, suffice to define the units; however, the morphologic nature of most mappable units on the Moon, is, of itself, suggestive of a certain lithologic composition, based on analogous terranes on Earth.