US Geological Survey, Miscellaneous Geologic Investigations Map I-351.

This was the first map of the Moon published by a US government agency and demonstrated the awakening of officialdom to the need to better understand the Moon. This particular map recognized only a few units and had little scientific importance. But author Hackman went on to develop the detailed geologic mapping of the Moon with Eugene Shoemaker that has become the model for all planetary mapping.

Sample of Map Figure 1: Generalized Photogeologic Map of the Moon (scale of original 1:3,800,000).

Yellow = Maria rocks; Brown = Pre-Maria rocks; Green = Post-Maria rocks. Dark lines indicate geologic structures such as faults, anticlines and monoclines.