Prairie (Fr., a meadow), the name applied by the early French explorers to the great fertile, treeless plains of North America which lie between Ohio and Michigan on the east and the arid plains on the west. The region over which they mainly extend is the western part of Ohio, nearly the whole of Indiana, Illinois, and Iowa, the southern part of Michigan, the northern part of Missouri, and portions of Wisconsin, Kansas, and Nebraska. Near Prairie du Chien in W. Wisconsin, the elevation of the prairies is about 400 ft. above the Mississippi. At Cairo in S. Illinois, the upper surface is from 100 to 250 ft. above the river, or 400 to 550 ft. above the sea. In the central portion of the state, near the Illinois Central railroad, the average elevation is from 650 to 750 ft. above the sea, and near the northern border of the state this increases to 800 or 900 ft., and some of the highest swells of the prairie are 1,000 ft. high. In S. Wisconsin the more elevated portions of the prairie are about 1,100 ft. above tide water. In Iowa the plateau du coteau des prairies of Nicollet, dividing the waters of the Mississippi from those of the Missouri, is from 1,400 to 1,500 ft. above the sea.
On the head waters of the Illinois and Wabash, and S. and W. of Lake Michigan, the prairies are very level and smooth, and are termed flat. Those of other regions, where the surface is undulating and broken by the depressions of the streams, are known as rolling prairies. The characteristic herbs of the prairies, as described by Prof. Gray in a paper on the " Flora of the Northern States," published in the "American Journal of Science" (2), xxiii., p. 397 (1857), would seem to be composite, especially helian-thoids of many species. Trees are met with upon the prairies under peculiar circumstances of moisture and soil, in scattered groups, called groves, or along the larger streams, or occasionally on low rocky ridges. West of the Mississippi they become less frequent, and near Ion. 98° W. they disappear altogether. The soil of the prairies is generally free from stones. In the swales and in some of the bottom lands the rich black vegetable mould is very deep, but on the upper prairies its depth is usually from one to two feet. The subsoil is almost invariably an argillaceous loam, more or less mixed in its lower portions with sand and occasional pebbles.
The total thickness of clay, sand, and loam amounts in some places near the larger rivers to 200 ft.; but the rock is often found in other places very near the surface; its immediate cover consists of layers 2 or 3 ft. thick of angular fragments. Water is generally found in the sandy stratum 15 to 30 ft. below the surface. Throughout the prairie region the underlying rocks are soft sedimentary strata, especially shales and impure limestones. Most of these on exposure disintegrate readily and crumble to soil. To the finely comminuted condition of these materials Prof. Hall ascribes the treeless character of the prairies. - The vast plains lying between the 99th and 104th meridians, and reaching from the Big Horn mountains on the north to the Llano Estacado on the south, differ from the prairies in being arid and partly desert, although irrigation generally renders them very fertile. The mound prairies near Puget sound, and in other parts of the Pacific coast, are so called because they are thickly studded with earth mounds, generally 3 or 4 ft. high and 30 to 40 ft. in diameter at the base.
Prof. Joseph Le Conte holds them to be the result of surface erosion under peculiar conditions.
Prairie, a central county of Arkansas, bounded E. in part by White river, which also intersects it, and N. by Cypress bayou, one of its branches, and intersected by bayou Me-toe; area, 1,050 sq. m.; pop. in 1870, 5,604, of whom 1,811 were colored. The Memphis and Little Rock railroad passes through it. The chief productions in 1870 were 81,618 bushels of Indian corn, 3,332 bales of cotton, 2,130 tons of hay, 11,335 lbs. of tobacco, and 70,850 of rice. There were 537 horses, 983 milch cows, 1,610 other cattle, and 4,(380 swine. Capital, Devall's Bluff.