Mapping by two of the great post-Civil War geological surveys of the American West overlapped in several areas, including a strip across northern Colorado [King and Hayden Surveys]. Prior to the publication of atlases [King–1876, Hayden–1877] geologists of these surveys exchanged little information, yet their final maps in areas of overlap are fairly similar. King's construction of topographical maps to serve as the basis for portraying geology was adopted by the other surveys. While the degree of detail shown and age interpretation of some stratigraphic units vary between the maps, overall geologic trends are similar. In 1878, King justified his survey expenses, writing that: “This exploration has not duplicated other surveys made by authority of Congress.” While overlap of map areas in part reflects varied goals of survey leaders and/or imprecisely defined survey and territorial boundaries, it also reflects the strong personalities and rivalry among these men and their unwillingness to share information. This set the stage for the consolidation of western surveys under the authority of a single agency, the newly formed U. S. Geological Survey with Clarence King as its first director.