Geographic and ecological region of Kansas and Oklahoma, United States
The Flint Hills, historically known as Bluestem Pastures or Blue Stem Hills,[1] are a region of hills and prairies that lie mostly in eastern Kansas. It is named for the abundant residual flint eroded from the bedrock that lies near or at the surface. It consists of a band of hills extending from Marshall and Washington Counties in the north to Cowley County, Kansas and Kay and Osage Counties in Oklahoma in the south, to Geary and Shawnee Counties west to east.[2] Oklahomans generally refer to the same geologic formation as the Osage Hills or "the Osage."
The Flint Hills Ecoregion is designated as a distinct region because it has the densest coverage of intact tallgrass prairie in North America. Due to its rocky soil, the early settlers were unable to plow the area, resulting in the prevalence of cattle ranches as opposed to the crop land more typical of the Great Plains. These ranches rely on annual controlled burns conducted by ranchers every spring to renew the prairie grasses for cattle to graze.
Explorer Zebulon Pike first coined the name the Flint Hills in 1806 when he entered into his journal, "passed very ruff flint hills". The underlying bedrock of the hills is a flinty limestone. The largest town in the area is Manhattan, Kansas, and the hills can be accessed from the Flint Hills Scenic Byway, which passes through the region.
Geology
The rocks exposed in the Flint Hills were laid down about 250 million years ago during the Permian Period. During this time, much of the Midwest, including Kansas and Oklahoma, was covered with shallow seas. As a result, much of the Flint Hills is composed of limestone and shale, with plentiful fossils of prehistoric sea creatures. The most notable layer of chert-bearing limestone is the Florence Limestone Member, which is approximately 45-foot thick (14m). Numerous roadcuts of the Florence Member are prominent along Interstate 70 in Riley County, Kansas. Unlike the Pennsylvanian limestones to the east, however, many of the limestones in the Flint Hills contain several bands of chert or flint. Because chert is much less soluble than the limestone surrounding it, the weathering of the limestone has left behind a clay soil with abundant chert gravel. Most of the hilltops in the region are capped with this chert gravel.
Due to shallow outcroppings of limestone and chert that lay just underneath the soil surface, corn and wheat farming were not practical over much of the area since plowing the land wasn't feasible. For this reason, cattle ranching became the main agricultural activity in the region.
Never having been ploughed over and sparsely developed, the Flint Hills represent the last expanse of intact tallgrass prairie in the nation.[4] They present the best opportunity for sustained preservation of this unique habitat that once covered the vast Great Plains. Most of the plains, such as the Central tall grasslands to the north, have better soil than the Flint Hills and a richer plant cover, but have almost entirely been converted to farmland.[2]
Tallgrass prairie is renewed by fire and grazing, which also keeps back the growth of trees and shrubs. Prominent grass species are big bluestem (Andropogon gerardi), switchgrass (Panicum virgatum), and Indian grass (Sorghastrum nutans).
Animals native to the Flint Hills include the American bison, which once grazed the area by the millions and were almost entirely exterminated, but have now been reintroduced. The elk that once roamed the region are gone.
In mathematics, the Flint Hills series (which is named after the region) is an infinite series for which it is unknown whether or not the series converges. The convergence of the Flint Hills series is related to how irrational the number π is. [10][11]
This article uses material from the Wikipedia article Flint_Hills, and is written by contributors.
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