IOWA, i'o-a ("tbe HawkeYe Stitt!), a north-central State extending from the Missis sippi River to the Missouri River, and occupy ing three and one-sixth degrees of latitude. It is bounded on the north by Minnesota, on the east by Wisconsin and Illinois, on the south by Missouri, and on the west by Nebraska and South Dakota. Area, 56,025 square miles and 550 water; it is 310 miles east and west, and 210 north and south. Capital, Des Moines. Pop. 1910, 2,224,771i 1915, 2,358,066. It is the six teenth State in order of admission to the Union, following the organization of the origi nal 13 colonies as States.
Topography.— Iowa is a part of the great central plain, and is chiefly undulating prairie, rising in gentle swells from the Mississippi River to a divide running diagonally, from a height of 1,694 feet in the northwest to a slight elevation in the southeast, with a parallel sub divide in the southwest. There are now no swamps and few natural forests. The only rough spots are the sharp bluffs where the rivers have cut their the through the glacial drift; the only woods, those along the streams altogether about 7,000 square miles of wood land, with oak, elm, hickory, black walnut, ma ple, cottonwood, linden, ash, box-elder, pine, cedar, etc. The eastern watershed, two-thirds of the whole State, is drained to the Mis sissippi by a series of streams, nearly all of which are parallel and have a southeastward course. The western part is drained to the Mis souri by shorter and swifter rivers, flowing first southwest and then south as the Missouri turns eastward. The chief Mississippi affluents are the Upper Iowa, the Turkey, the Maquoketa, the Wapsipinicon, the Iowa and the Cedar the °main" stream, the Iowa — 375 miles, its tributary,D the Ceda!-, 400 miles, the two form ing the second largest interior system of the State and joining not far from the mouth of the Iowa), the Checaqua, or Skunk, and lastly the Des Moines with its numerous affluents, far the greatest and commercially the most im portant as well as the finest scenically, rising in Minnesota and running diagonally across the entire State in a course of 550 miles, with a basin of 14,500 square miles. The State is pro longed by a southeastern corner to include the entire channel of the Des Moines. The north ern part of the State has a continuation of the many small, clear, pebbly lakes of Minnesota in glacier-scored pits; some of them the Walled Lakes — surrounded each by a natural wall of loose stones. The largest are Spirit Lake and the two Okoboji lakes in Dickinson County, and Clear Lake in Cerro Gordo County, all popular summer resorts. West Okoboji, of great depth, lies between wooded hills, and is indented by several picturesque °pointss' or promontories.
Climate.— The winter climate is somewhat severe because of the location of the State in the midst of a great continent, such severe winters being experienced in all mid-continental climates in middle and northern latitudes. The
severity is tempered by freedom from ex cessive moisture. The State is one of the healthiest in the Union, several of the streams in the northeast having rocky channels, and none having the miasmatic bottom-lands found farther south. The dry, pure air of its roll ing prairies affords a valued sanatorium for consumptives. The average annual temperature is 47.4°. The average monthly temperature ranges from 18° in January to 74 in July. The absolute range of temperature during the 26 years of record-1890 to 1915, inclusive—is 160°, the highest being 113°, in July, 1901, and the lowest 47° below zero, in January 1912. The average precipitation, rain and melted snow, is 31.97 inches, of which 80 per cent falls during the seven months, April to October, in clusive, and more than 52 per cent of the an nual amount falls during the critical crop months, May to August, inclusive.
Geology.— No less than five separate sheets of glacial drift cover the State, giving a re markable variety of productive soil, as well as clays for industrial purposes. The underlying rocks are inclined from northeast to southwest over the greater part of the State, and many of them outcrop in the eastern part of the State in lines which extend from northwest to southeast. The oldest formation is the Sioux Quartzite, which is exposed in the northwest ern corner. In the eastern and southern parts of the State from northeast to southwest are found Cambrian,. Ordovician, Silurian, Devo nian and Carboniferous in succession. Creta ceous deposits overlie the older formations generally through the northwest part. The most valuable mineral beds are the fields of bituminous coal which cover about one-fourth of the entire area of the State and which yielded in the year 1917 9,049,806 tons, valued at $21,096,408; employing 15,464 persons. It is the leading coal State west of the Mississippi except Colorado, and coal is a great factor in all the northwestern industries. Its limestone, a fine grade of building stone, near Marshall town, Anamosa and other points, was quarried to the extent of $610,534 in 1916. Its gypsum, from the rocky hills in the vicinity of Fort Dodge, is the basis of a fast increasing manu facture of stucco, hard wall plaster and paint. The output of gypsum in 1917 was worth $1,811,432. Iowa also has high grade clays for pottery, fire and building brick, sewer pipe and drain tile. The State ranks seventh in the United States in the value of its clay products. Its output of clay products in 1916 amounted to $7,375,716. Considerable mineral water also is consumed, that from the Colfax Springs being in the lead. The total number of gal lons in 1916 was 148,732. Iowa's output of sand and gravel in 1916 amounted to $980,272. The output of cement in 1917 realized $6,870,863. The value of the total mineral production for 1916 was $29,158,908.