Mississippi and Missouri River Commis The Engineers corps, War Department has made a detailed survey of the Mississippi River and of its principal tributaries, showing topography of the shore, 1876-84. These sur veys were intended primarily for guidance in the many engineering problems connected with improving the waters for navigation, a task on which the government had expended nearly $150,000,000 up to end of June 1916. The War Department has made special surveys for many river and harbor improvement projects.
Hydrographic Office this branch of the Navigation Bureau of the Navy Depart ment is entrusted the preparation of many kinds of data relating to navigation. Numerous maps are produced in many cases based on original surveys.
Forest The Forest Service of the Agricultural Department has made sur veys in most of the Forest Reservations in some cases with detailed representation of topography and distribution of various kind§ of timber. A series of atlases has been published and many maps are on file in the various offices of the bureau. Some work of this kind was also done by the United States Geological Survey in 1897 '900 and many maps were published in annual reports and professional papers. Since 1897
this survey obtains data as to forested areas in all districts mapped topographically.
Soil The Agricultural Depart ment has made surveys of soils in many parts of the United States, publishing the results on the detailed topographic maps by the United States Geological Survey. These soil maps are issued for gratuitous distribution.
Biological Survey.— The Agricultural De partment is also conducting a survey to ascer tain the geographic distribution of animals and plants.
Bibliography.— 'United States Geological and Geographic Surveys,' G. M. Wheeler, Vol. I, pp. 519-745; 'Report of Third International Geographic Congress' (Venice, Italy, by G. M. Wheeler, 48th Congress, Second Session. H. of R. Ex. Doc. 270,1885) ; Emmons, S. F., 'The Geology of Government Explorations) (Geo logical Society of Washington, 1896); Merrill, G. P., 'Contributions to the History of Ameri can Geology) (Report of United States National Museum, 1904, pp. 189-734).