MISSOULA, mĭ-zo͞o′lȧ. A city and the county-seat of Missoula County, Mont., 125 miles west by north of Helena; on the Hell Gate River, and on the Northern Pacific Railroad (Map: Montana, C 2). It is the seat of the State University, and has a public library and hospitals, one maintained by the Northern Pacific Railroad. The city is in a farming and fruit-growing, lumbering, and mining region, for which it is an important distributing centre, and controls a considerable trade in grain, fruit, and produce. There are a brewery and bottling works, and railroad shops of the Northern Pacific, founded in 1864, Missoula was first incorporated in 1887, the charter of that year now operating to provide for a mayor, chosen biennially, and a unicameral council. Population, in 1890, 3426; in 1900, 4366.
MISSOURI, mĭz-zo͞o′rĭ, local pron. mĭz-zo͞o′rŭ. A central State of the American Union, situated about midway between the Rocky Mountains and the Atlantic Ocean, and midway between the Dominion of Canada and the Gulf of Mexico. It lies west of the Mississippi River, which separates it from Illinois, Kentucky, and Tennessee. Iowa, separated by the parallel of latitude 40° 30′ N., is on the north, and Arkansas, separated by the parallel of latitude 36° 30′ N., except for a small projection of Missouri between the Mississippi and Saint Francis rivers, which extends 34 miles south between Tennessee and Arkansas, is on the south. On the west, Missouri is separated from Indian Territory and Kansas by the line of longitude 114° 43′ W., as far north as the junction of the Missouri and Kansas rivers, from which points the Missouri River completes the western boundary, separating Missouri from Kansas and Nebraska. The distance between the northern and southern boundaries is 285 miles, and the greatest extension from east to west is slightly more. It contains a total area of 69,415 square miles, of which water comprises 680 square miles and hind 68,735 square miles. It ranks fifteenth in size among the United States.
Topography. The northern portion of the State was covered by the glacial ice sheet, the southern limit of which was bounded by the line of the Missouri River. It is a wide expanse of gently rolling plains, generally of treeless prairie, belts of timber occurring only along the streams. South of the Missouri the land rises gradually to the broad flat dome-like elevation of the Ozark Mountains. This range extends in a southwesterly direction and rises to a height of 1700 feet in the west, and in the east to 1800 feet in the peaks of Pilot Knob and Iron Mountain. The uplands are marked by a series of escarpments of harder strata standing out in precipitous bluffs from 200 to 300 feet high, but sloping off gently on the opposite sides in the direction of the dip of the strata. The lower ground between represents the softer strata which have worn down to the lower level since the post-Cretaceous uplift. West and north of the broken and rugged Ozark Plateau extends prairie country, and prairie areas are also found scattered through the eastern part. The southeastern portion is bottom land, marshy in character. Here the levees along the Mississippi are required to protect the low-lying land from inundation.
Hydrography. The whole State is drained into the Mississippi, either directly or through its tributary, the Missouri, which traverses the State from west to east. Through the extreme southern portion Hows the White River, which enters the Mississippi in the State of Arkansas; the southwestern corner drains westward into the Arkansas River. The importance of the large rivers, with regard to navigation, however, is not commensurate with their size. The river beds of the Ozark region were worn to base-level during Cretaceous time. At the close of that period the region was uplifted, and the meandering rivers lowered their gradients in situ, so that they now cross and recross the ridges regardless of structure. The Osage River is a classical instance of entrenched meanders.
Climate. Missouri lies in the milder half of the warm temperate zone. Being far inland, the State is subject to the extremes of a continental climate, which are all the more accentuated by the fact that it is in the path of frequent cyclonic storms. The average January temperature ranges from 35° F. in the southeastern to 20° in the northwestern corner. For July the average temperature is 80° in the extreme south and 75° in the extreme north. The southwestern winds from the arid plains in sununer sometimes send the mercury up to 105°, while the anticyclones of winter carry a minimum of 10° below zero to the southern border, and 20° below to Saint Louis, thus giving that city an annual range of 125°. The southeastern extremity of the State has not a day in the year with the average temperature below freezing, but the record rises rapidly northward, there being 30 such days at Springfield, 60 at Jefferson City, and 90 at Rockport. The summers are pleasantly tempered in the Ozark Plateau. The rainfall ranges from 35 inches per year in the north to 60 inches at the Arkansas line. While this is well distributed through the year, there is a marked minimum in the winter season, and maximum in the summer season. Droughts lasting thirty days sometimes occur. Snow falls on the average to the depth of 20 inches in the latitude of Saint Louis, and less than 10 inches at the Arkansas line, though it rapidly disappears and seldom covers the ground many days. The average relative humidity for the year is less than 70 per cent. over the whole State. The prevailing winds are west and northwest in January, and south in July. There are on the average 30 thunder storms in the year, with a maximum frequency in June. The northern part of the State is in the area of maximum tornado frequency, and very severe and destructive tornadoes occasionally occur.
Geology. The geological history of Missouri covers a lapse of time from Algonquian into late Carboniferous, giving surface outcrops of Algonkian, Cambrian, Ordovician, Silurian, Devonian, Subcarboniferous, and Carboniferous, with a subsequent absence of deposits until Pleistocene time. The old land, which now outcrops in the southeastern onarter of the State, in Saint Francis, Iron, Madison, Wayne, and Reynolds counties, is made up of porphyritic eruptives, but with lavas often bedded; the elastics are sometimes porphyry conglomerates, the materials of which have evidently been derived from the underlying porphyry flows. At Pilot Knob the iron ores are associated with the conglomerates. These old lands show analogies with the Upper Huro-
