south by Kansas and Colorado, and on the west by Wyoming and Colorado. Its shape is that of a rectangle whose eastern end is cut off diagonally by the Missouri River, and whose southwestern corner is overlapped by the northeastern corner of Colorado, its extreme length from east to west is 420 miles, and its breadth from north to south 208 miles. Its area is 77,510 square miles, of which 670 square miles are water, and 76,840 square miles, or 49,177,600 acres, land. It ranks thirteenth in size among the States.
Topography. Nebraska lies in the region of the great plains skirting the eastern slope of the Rocky Mountains, toward whose foothills it rises in a gentle, undulating incline. The whole western half of the State lies at an elevation of more than 2500 feet above the sea. On the other hand, there are but few eminences rising much above the general level of the plain, except in the extreme west, where the foothills of the Rocky Mountains begin to appear. The highest point here is Wildcat Mountain, 5038 feet above the sea. As the rivers are deeply trenched in the soft drift material, their flood-plains in the east along the Missouri, the Platte, and their larger tributaries are lined with steep or rounded bluffs sometimes of considerable height. Nebraska is a prairie State.
Hydrography. The State is drained entirely by the Missouri River and its tributaries. Owing to the gentle and regular slope of the land, most of these rivers flow in nearly straight parallel lines east or southeastward, and they are for the most part wide and also shallow. The three principal rivers, besides the Missouri (on the boundary), are the Platte in the centre, the Niobrara in the north, these two flowing through the whole length of the State, and the Republican in the south, the latter coming from Kansas, and returning to that State to form the Kansas River.
Climate. The climate is continental, dry, and exhilarating. The mean temperature for January is 19.7° and for July 74.8°. The extremes are very great, the mercury sometimes falling to -42° and at times rising to 114°. The nights are cool. The climate of the western third of the State is, however, quite arid, and differs considerably from that of the eastern third, where agriculture is wholly successful. The annual rainfall is 23 inches, but this is very unevenly distributed. In the east it is sufficient to support agriculture, ranging from 30 inches on the average to a local maximum as high as 50 inches. In the western half it is below 20, and in the extreme west as low as 12 inches, so that here agriculture cannot be carried on successfully without irrigation. The greatest amount of rain falls in May and June, and more than three-fourths of the annual rain falls during the six months of the growing season, April to September. The prevailing winds are from the northwest, and these generally temper the summer heat, but occasionally the heat is aggravated by the hot winds from the southwest.
Soil. More than half of the State is covered with glacial drift and loess, the drift being confined to the eastern counties. The loess forms a soil of inexhaustible fertility. Its deposits range in thickness from 5 to 150 and even 200 feet, and though soft and easily excavated, it is very compact and able to withstand moisture and exposure. The bluffs along the bottom-lands are composed of this material. The alluvial lands of the river valleys also afford excellent soil, though scarcely exceeding the loess in quality, and as the State was anciently a lacustrine bed, and later a region of peat bogs, large areas are covered with a very black vegetable mold which in some places becomes true peat, and which has given the dark color to the rivers, whence the popular name of the State is derived. Considerable areas in the west, as much as 20,000 square miles, are covered with sand dunes. These are found partly in the southwestern corner, but chiefly in the large and arid area north of the Platte and west of the 100th meridian. In the extreme west the Tertiary marls, even in the Bad Lands, can be made productive by irrigation.
For Flora and Fauna, see the articles Rocky Mountains and United States.
Geology and Minerals. Except in the Bad Lands of the northwest and in some other isolated localities, formations older than the Pleistocene are nowhere exposed. They are composed of nearly horizontal strata outcropping below the drift in wide bands running southwest to northeast. Four principal formations are represented, which in order from southeast to northwest are the Upper Carboniferous, Permian, Cretaceous, and the Miocene and Pliocene Tertiary. The Miocene is the one which crops out in the Bad Lands. Glacial drift covers the eastern third of the State, the remaining Pleistocene formation consisting of alluvial deposits laid down in the lakes which were formed at the close of the glacial period. Clay and a little building stone are the only important minerals. The clay deposits afford material for the production of brick and tile; the product for 1900 was valued at $683,958, three times the value of the product in 1895.
Agriculture. In agricultural development the State advanced rapidly during the last three decades of the nineteenth century, and at the end of the period ranked as one of the most important agricultural States. In 1900, 60.8 per cent. of the total land area was included in farms, and of this 61.6 per cent. was improved. Efforts at irrigation in the arid areas of the west have been attended with some success, the irrigated acreage reported in 1899 being 148,538, of which about 90 per cent. was watered from the North Platte River. In some regions there are supplies of underground water, which can be utilized by means of windmills and small reservoirs—a system which promises to be of some importance in the agricultural development of the arid regions. Since 1880 the average acreage of farms increased from 156.9 acres to 246.1 acres. This is due to the establishment of extensive live-stock ranches in the western part of the State and the cultivation of large corn-producing areas, and is in spite of the tendency to divide farm holdings which has characterized the same period in the eastern part of the State. The number of tenant-operated farms is increasing very rapidly, and amounted in 1900 to 36.9 per cent. of the total number of farms.
Corn is the leading crop, nearly one-half of the cultivated acreage of the State being devoted to it. In 1880 the acreage of wheat was only slightly less than that of corn, but in the following decade there was an actual decrease of more than two-fifths in the area devoted to it, which, how-
