In studying the various types of structures it is interesting to learn how the natural environments influenced the form of dwellings erected by the tribes of a particular section. Thus in the densely timbered country of the north, about the headwaters of the Mississippi and far beyond, the mat and bark covered wigwams were developed and employed practically to the exclusion of all other forms of habitations. But on the plains, and in the regions bordering the great buffalo ranges, the skin-covered conical tipis predominated, although other forms were sometimes constructed by the same people. The earth lodges as erected by certain tribes of the Missouri Valley were the most interesting native structures east of the Rocky Mountains, and these at once suggest the _Rotundas_, or great council houses once built by the Cherokees and Creeks east of the Mississippi. In treating of the habitations and villages of the several tribes references have been made, incidentally, to the manners and ways of life of the people who once claimed and occupied so great a part of the present United States. AUTHORITIES CITED. ALLEN, JOEL ASAPH. (1) History of the American Bison, Bison americanus. _In_ Ninth Annual Report of the United States Geological Survey, for the year 1875. Washington, 1877. ATKINSON, HENRY. (1) Expedition up the Missouri, 1825. Doc. 117, 19th Congress, 1st session, House of Rep. War Department. Washington, 1826. BELL, WILLIAM A. (1) New Tracks in North America. London, 1870. BRACKENRIDGE, H. M. (1) Views of Louisiana; together with a Journal of a Voyage up the Missouri River, in 1811. Pittsburgh, 1814. BRADBURY, JOHN. (1) Travels in the Interior of America, in the years 1809, 1810, and 1811. Liverpool, 1817. BUSHNELL, D. I., JR. (1) Native Villages and Village Sites East of the Mississippi. Bulletin 69, Bureau of American Ethnology. Washington, 1919. (2) Ojibway Habitations and other Structures. _In_ Report of the Smithsonian Institution for the year ending June 30, 1917. Washington, 1919. (3) Ethnographical Material from North America in Swiss Collections. _In_ American Anthropologist, Vol. 10, No. 1, Jan.-Mar. 1908. CARVER, JONATHAN. (1) Travels through the Interior parts of North America, in the years 1766, 1767, and 1768. London, 1781. Reprint New York, 1838. CATLIN, GEORGE. (1) Letters and Notes on the Manners, Customs, and Conditions of the North American Indians. London, 1844. 2 vols. COCKING, MATTHEW. (1) Journal of ... 1772-1773. _In_ Proceedings and Transactions of the Royal Society of Canada. Vol. II, Third series. 1908. COLTON, C. (1) Tour of the American Lakes ... in 1830. London. 1833. 2 vols. CULBERTSON, THADDEUS A.