information about U.S. maps, charts, aerial and space photographs and images, geodetic control, cartographic and geographic digital data, and other related information; distribution of earth science information to the public; and sale of maps and maprelated products directly and through commercial map dealers.

• Cartographic and geographic research and development, which include efforts to

portrayed by the model. Thus, this part uses information from the geologic map, the geophysical maps, and the known deposits and occurrences.

The second part of the descriptive model, the "Deposit Description," provides the identifying characteristics of the deposits themselves, particularly emphasizing aspects by which the deposits might be recognized through their geochemical and geophysical anomalies. For 25 models, a cartoon-style map or cross section illustrates ore controls, zoning patterns, or other features of the model. Thus this part is primarily used to classify the known. deposits and occurrences in and near the area being assessed. In appendixes to the Bulletin, the models are extensively