This figure is a filtered version of the Bouguer anomaly map of a portion of central Colorado. The colors show the intensity of the anomalies as the values increase from violet to red. Contour lines at intervals of 5 mGal are included to add precision in regard to the location of specific anomaly values. This filter has removed wavelengths greater than 150 km and enhanced the anomalies due to the sedimentary basins associated with North and South Park. The northeast-trending gravity minimum crossing the lower 1/3 of the map is associated with the Colorado mineral belt and probably a granitic body in the upper crust.