IOWA, l'oN•wIt (popularly known as the 'llawk eye State'). One of the North Central States of the United States. It lies het ween latitudes 40° 311' and 43' 30. N.. and between longitudes S9° 5' and 90° 31' NV.. and is bounded on the north by :Nlinnesota, on the east by Wisconsin and Illinois, from which States it is separated by the Mississippi River, on the south by Nlissouri, and on the west by Nebraska, front which it is separated by the 'Missouri River, and by South Dakota. Its shape is nearly that of a reetangle, inpa..ining front east to west and 305 miles from north to smith; its riven is 56,025 square miles, and it ranks wonty•seconol in size among the States of the TOPOtiltAtillY. Iowa lies entirely within the great central prairie belt. Its surface is a pla teau with an average height of 1000 feet in the northwestern corner of the State, the highest point, NValietil in I i'Brien Comity, being 1502 feet above sea•level. The plateau slopes gradually in gently rolling prairies toward southeast. where its average altitude is about 4111) feet. It is only where the rivers have eroded their chan• tads through the glacial drift, forming steep bluffs, and in sonic places rocky cartons, that the country is at all rugged. The greater portion of its area, though not perfectly level, is so free from natural obstructions that the country roads are laid out in squares, crossing at right angles with the absolute regularity of n checker-board. The State is divided into two hydrographie Sys tent., the eastern two-thirds being drained by the direct affluents of the Mississippi, and the west ern third by those of the Missouri. The divide between the two systems runs obliquely across the State from northwest to southeast. From this the Alississippi affluents flow all in a south east direction, and the .Missouri affluents all to the southwest. The principal of Oar former are the Turkey, Wapsiitinieon, Red Cedar, Iowa, Skunk, and Des Moines rivers, the last being the largest rivet- within the Stale. The principal Alissou•i affluents are the Big Sioux, forming most of the South Dakota boundary, the Little Sioux, the Nislinaltotna, and the Nodaway. 'Many of those streams are navigable for very small craft, lint, owing to the railroads, they are un neeessary as waterways and little used. Like all glaciated areas. Iowa is dotted, especially in the northern part. with numerous small hut often beautiful lakes, several of Odell are fa• vorite resorts, such as Spirit Lake in Dickinson County near the north boundary, a beautiful sheet of water, by 5 miles, with picturesque, wooded shores. Forest areas are small in Iowa; they are chiefly •omtined to the faces of the bliiffs along the river-courses. The most common trees are the oak, elm, eottonwood, hickory, and maple, while scanty forests of pine and cedar are fctind I») some of the bluffs. Grasses are the predominating feature of the landscape as well as of the flora of the State.
CtastATE AND SOIL. The climate in different parts of the State shows only slight variations, which are due to differences in latitude and alti tude. It is of the eontinental type, with great variations in temperature between summer and winter. The mean annual temperature is 47.4°
F., and the extremes recorded during the past decade are —40' and 110°, showing an extreme range of 150°. The average anneal rainfall is S0.11 inches, more than two-thirds of which usually falls during the six erop months. April to October. These coition.; hut not excessive rains, coinciding with continued high temperatitre dur ing the summer months, are, next to the rich soil, the chief cause of Iowa's agricultural prosperity.
Practically the whole of Iowa is arable land. The soil may be divided into three distinct kinds, alluvial soil, glacial drift, and loess. The allu vial soil consists of recent deposits on the bottom lands of the principal rivers; the principal tract is the Missouri Bottoms, 150 miles long, and from 5 to 20 miles wide. This is, of course, the richest soil of the State, but is, nevertheless, rivaled by the drift soil. The latter consists of a fine loamy mixture of clay and sand, with a little gravel. It is of almost inexhaustible rich ness, and scarcely needs fertilizing. It covers by far the greater part of the State. The loess is a fine yellowish sand highly charged with car bonate of lime. It is found in various parts of the State, generally along the margins of the various drift areas, and is generally considered to be of glacial origin.
For flora and fauna, see UNITED STATES. GEOLOGY AND MINERAL RESOURCES. Owing to the heavy covering of drift, a thorough geological survey of Iowa is attended with difficulties. Nevertheless our knowledge of the rock forma tions is fairly complete. In more than three fourths of the State the surface consists of Paleozoic rocks appearing in parallel belts run ning northwest to southeast. Beginning at the northeastern corner, there is a narrow belt of Cambrian formation consisting of Potsdam sand stone: then follow the Silurian, Devonian, and the Lower and Upper Carboniferous formations, the latter occupying the southwest corner of the State. The northwestern part is covered by ex tensive Cretaceous beds deposited across and over the belts of the older strata. Finally, in the extreme northwest corner there are outcrop pings of metamorphosed rock of the Algonkian period, known as Sioux quartzite, the oldest for mation in the State. Over the entire surface, the exception of a small driftless area in the northeastern corner, is a deposit of glacial drift from a few inches to several hundred feet in thickness. It consists mainly of fine rock fragments with but few boulders and pebbles. The limits of the various drift sheets, the older in the south and the later in the north, are clear ly defined, although there are no typical mo raines.
The most valuable of Iowa's mineral re sources are the extensive bituminous coal beds found in the southeastern quarter of the State. Lead and zinc ores have been mined in con siderable quantities in the Galena limestone of the Lower Silurian formation of the northeast. Extensive deposits of gypsum are also found, and various other minerals occur in smaller quantities, limonite iron ore being the only me tallic deposit besides lead which seems at all promising. The limestones of the Devonian and Upper Silurian formations furnish an inexhausti ble supply of building-stone of the finest quality.