Millions of years ago much of Kansas was the floor of an inland sea. The land was built up by the deposit of soil and vegetable matter from streams feeding this sea. Today, this soil is among the most fertile in the world, and it contains many prehistoric fossils.
Many people think of Kansas as one long, featureless plain. But Kansas has three separate geographical regions: the Dissected Till Plains in the northeast; the Southeastern Plains, consisting of the Osage Plains and the Flint Hills to the west; and the Great Plains, covering the western half of the state.
The Dissected Till Plains, in the northeast, are an area of rich soil left by glaciers thousands of years ago. Over tens of thousands of years, rivers and streams have cut through (dissected) the landscape and created high bluffs.
The Southeastern Plains cover Kansas to the Oklahoma border in the south and extend west toward the center of the state. The landscape is gently rolling, interrupted by a few hills. The Southeastern Plains can be divided into two sections; the Osage Plains and the Flint Hills. Osage Plains, in the east, were formed by the erosion of limestone and shale. In contrast, the Flint Hills, in east-central Kansas, are made up of gentle, rolling limestone and flint ridges, largely treeless, and covered with bluestem. They are the only extensive unplowed area of true prairie remaining in the United States.
The western half of Kansas is covered by the Great Plains. The far western section consists of high plains with few trees and appears flat and endless. These plains are creased with shallow gullies called draws, which were formed by thousands of years of erosion. They contain striking geologic formations such as Castle Rock, which consists of chalk spires rising high above the plains. Monument Rocks, a few miles to the west, resemble sphinxes. Near Jetmore is Horse Thief Canyon, which is like a miniature Grand Canyon.
More than 50,000 streams run through the state, and there are hundreds of artificial lakes. Major rivers include the Missouri, which makes up the state’s northeastern boundary; the Arkansas, which runs through Wichita; and the Kansas (Kaw), which runs through Topeka and joins the Missouri at Kansas City.
The main rivers are the Kansas and the Arkansas. Tributaries of the Kansas are the Big Blue, the Republican, the Solomon, the Saline, and the Smoky Hill, all in northern Kansas. The Arkansas River flows into the state from Colorado and winds through southwestern and south-central Kansas, continuing through Oklahoma and Arkansas to the Mississippi River. Tributaries of the Arkansas are the Cimarron, the Verdigris, and the Neosho.
Kansas has few natural lakes, but a large number of man-made reservoirs have been constructed throughout the state. Among the largest are Clinton Reservoir near Lawrence, Milford Reservoir west of Manhattan, and Wilson Reservoir in roughly the centre of the state.
Kansas has a temperate, continental climate, with hot summers and cold winters, but few long periods of extreme hot or cold. The annual average temperature is 55°F (13°C). Normal annual precipitation ranges from less than 20in (500 mm) in the west to more than 40in (1,000mm) in the southeast. The record high is 121°F (149°C), recorded near Alton on 24 July 1936, and the record low is 40°F (-40°C), registered at Lebanon on 13 February 1905. Kansas lies in the heart of tornado alley and tornadoes are a regular fact of life in Kansas. Dodge City is said to be the windiest city in the US, with an average wind speed of 14mph (23kph).
