On the basis of magnitude and extent of mean gravity anomalies for 5° squares, 19 areas on the earth were selected as markedly positive; 14, as markedly negative; 10, as exceptionally ‘mild.’ Other geological and geophysical data for each of these 43 areas were examined. On the basis of certain patterns of correlation, eleven types of areas were defined. It was found that, where characteristics of different types appeared, certain characteristics were dominant over others. In general, characteristics associated with positive anomalies were dominant over ones associated with mild or negative anomalies, and characteristics associated with recent tectonics dominant over ones associated with ancient. The eleven types in order of dominance, with sign and a leading example of each given in parentheses, are: trench and island arc (+, Indonesia-Philippines), Cenozoic oceanic flood basalts (+, Iceland-North Atlantic), Cenozoic orogeny with Quaternary extrusives (+, Caucasus), Quaternary glaciation (−, Canadian shield), vigorous ocean rise (0, southeast Pacific), current orogeny without extrusives (−, Himalayas), ocean basin (−, Somali-Arabian), continental basin (−, Parnaiba basin), pre-Cenozoic orogeny (0, eastern United States), continental shield (0, Brazilian shield), pre-Cenozoic oceanic floor basalts (0, Darwin rise). The strongest correlation found was between positive gravity anomalies and Quaternary volcanism. Positive correlation of gravity anomalies with topography residual to a fifth-degree figure is almost universal. The extent to which the different area types relate to the global tectonics inferred from paleomagnetic and seismic data varies from strong (e.g., trench and island arc, vigorous ocean rise) to negligible (e.g., Cenozoic oceanic flood basalts, Quaternary glaciation). The lack of systematic correlation between temperature indicators (heat flow, Pn velocities, seismic station delays) and gravity anomalies indicates that horizontal variations in petrology are significant.