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The Loess Hills are a formation of wind-deposited loess soil in the westernmost parts of
Iowa Iowa () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wiscon ...

Iowa
and
Missouri Missouri is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspaper in ...

Missouri
, and the easternmost parts of
Nebraska Nebraska () is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspaper ...

Nebraska
and
Kansas Kansas () is a U.S. state, state in the Midwestern United States, Midwestern United States. Its Capital city, capital is Topeka and its largest city is Wichita, Kansas, Wichita. Kansas is a landlocked state bordered by Nebraska to the north; ...

Kansas
, along the
Missouri River The Missouri River is the longest river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its ...
.


Geology

The Loess (, , or ) Hills are generally located between east of the
Missouri River The Missouri River is the longest river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its ...
channel. The Loess Hills rise above the flat plains forming a narrow band running north–south along the Missouri River."Geology of the Loess Hills, Iowa"
USGS
These hills are the first rise in land beyond the
floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows int ...
, forming something of a "front range" for Iowa, and parts of Missouri and Nebraska adjacent to the Missouri River. The Loess land formations of Iowa extend north into South Dakota and is a feature of three state Parks in South Eastern South Dakota. Union Grove State Park, Newton Hills State Park and Blood Run State Park. During the last Ice Age,
glacier A glacier (; ) is a persistent body of dense ice Ice is into a state. Depending on the presence of such as particles of soil or bubbles of air, it can appear transparent or a more or less bluish-white color. In the , ice is abunda ...

glacier
s advanced into the middle of North America, grinding underlying rock into dust-like "
glacial flour Rock flour, or glacial flour, consists of fine-grained, silt Silt is granular material A granular material is a conglomeration of discrete solid, macroscopic scale, macroscopic particles characterized by a loss of energy whenever the particl ...
." As temperatures warmed, the glaciers retreated and vast amounts of meltwater and sediment flooded the
Missouri River Valley The Missouri River Valley outlines the journey of the Missouri River from its headwaters where the Madison River, Madison, Jefferson River, Jefferson and Gallatin Rivers flow together in Montana to its confluence with the Mississippi River in the S ...
. The sediment was deposited on the flood plain, creating huge
mud flat Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetland A wetland is a distinct ecosystem that is flooded by water, either permanently or seasonally, where oxygen-free processes prevail. The primary ...
s. When meltwaters receded, these mud flats were exposed. As they dried, the fine-grained
silt Silt is granular material A granular material is a conglomeration of discrete solid, macroscopic scale, macroscopic particles characterized by a loss of energy whenever the particles interact (the most common example would be friction when gra ...
was picked up by strong prevailing westerly winds. Huge dust clouds were moved and redeposited over broad areas. The heavier, coarser silt was deposited close to the Missouri River flood plain, forming vast
dune A dune is a landform A landform is a natural or artificial feature of the solid surface of the Earth or other planetary body A planet is an astronomical body Astronomy (from el, ἀστρονομία, literally meaning the ...

dune
fields. The dune fields were eventually stabilized by grass. Due to the erosive nature of loess soil and its ability to stand in vertical columns when dry, the stabilized dunes were eroded into the corrugated, sharply dissected bluffs we see today. The dominant features of this landscape are "peak and saddle" topography, "razor ridges" (narrow ridges, often less than wide, which fall off at near ninety-degree angles on either side for or more), and "cat-step" terraces (caused by the constant slumping and vertical shearing of the loess soil). The soil has a characteristic yellow hue and is generally broken down into several units based on the period of deposition (Loveland, Pisgah, Peoria). Loess is known locally as "sugar clay" because it can be extremely hard when dry, but when wet, loses all cohesion. The Loess Hills of Iowa are remarkable for the depth of the drift layer, often more than deep. The only comparable deposits of loess to such an extent are located in
Shaanxi Shaanxi (; , ; Chinese postal romanization, alternately Shensi) is a landlocked Provinces of China, province of the China, People's Republic of China. Officially part of Northwest China, it borders the province-level divisions of Shanxi (NE, ...

Shaanxi
,
China China (), officially the People's Republic of China (PRC; ), is a country in East Asia East Asia is the eastern region of Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere ...

China
.


Geography

Today, the hills stretch from Blood Run Site in South Dakota in the north to Mound City, Missouri in the south. Loess topography can be found at various points in extreme eastern portions of Nebraska and Kansas along the Missouri River Valley, particularly near the Nebraska cities of Brownville, Rulo,
Plattsmouth Plattsmouth is a city and county seat of Cass County, Nebraska, Cass County, Nebraska, United States. The population was 6,502 at the 2010 United States Census, 2010 census. History The Lewis and Clark Expedition passed the mouth of the Platte R ...
, Fort Calhoun, and
Ponca The Ponca ( Páⁿka iyé: Páⁿka or Ppáⁿkka pronounced ) are a Midwestern The midwestern United States, often referred to simply as the Midwest, is one of four census regions of the United States Census Bureau The United States Ce ...
, and the Iowa cities of Hamburg and Sidney. South Eastern South Dakota has three State Parks that feature the Loess formations, Union Grove State Park, Newton Hills State Park and Blood Run State Park all are south of Sioux Falls. The Big Sioux River separates South Dakota Loess Hills from Iowa Loess Hills and follow along the eastern edge of Brule creek in South Dakota. The hills are usually no more than above the Missouri River bottoms. However, in some areas, such as Murray Hill in Harrison County, Iowa, the Loess Hills can rise over above the adjacent Missouri River floodplain.


Biology

The Loess Hills have abundant oak-hickory hardwood forests and some of the last remaining stands of in the region. The invasion of prairie and oak savanna areas by woodland species such as red cedar (not native to the Hills) is threatening the stability of the fragile soils, as well as diminishing the native ecosystems found there. The areas of native prairie comprise
big bluestem ''Andropogon gerardi'', known commonly as big bluestem, tall bluestem, bluejoint, and turkeyfoot, is a species of tall grass Poaceae () or Gramineae () is a large and nearly ubiquitous family In , family (from la, familia) is a of ...
and
little bluestem ''Schizachyrium scoparium'', commonly known as little bluestem or beard grass, is a species of North American prairie grass native to most of the contiguous United States (except California, Nevada, and Oregon) as well as a small area north of t ...
, , , and
forb A forb or phorb is a herbaceous Herbaceous plants are vascular plants that have no persistent wood, woody stems above ground, including many perennial plant, perennials, and nearly all Annual plant, annuals and Biennial plant, biennials. Def ...
s such as
yucca ''Yucca'' is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), circumscr ...

yucca
,
pasque flower The genus ''Pulsatilla'' contains about 40 species of herbaceous plant, herbaceous perennial plants native to meadows and prairies of North America, Europe, and Asia. Derived from the Hebrew word for Passover, "pasakh", the common name pasque flow ...

pasque flower
and lead plant (false indigo). Many of the prairie species found in the Loess Hills are outside of their normal range of distribution, with plants like spiny-leafed yucca and prickly pear cactus being more common further west, in the Sandhills of central Nebraska. In 1984, a previously undiscovered fern, the Prairie Moonwort, was discovered in the Hills and is thought to be endemic to the Hills. Common fauna of the modern Loess Hills include ,
coyote The coyote (''Canis latrans'') is a species of canis, canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecologica ...

coyote
,
wild turkey The wild turkey (''Meleagris gallopavo'') is an upland ground bird native to North America North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be described as ...

wild turkey
,
badger Badgers are short-legged omnivore An omnivore () is an animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotro ...

badger
,
bobcat The bobcat (''Lynx rufus''), also known as the red lynx, is a medium-sized cat The cat (''Felis catus'') is a domestic Domestic may refer to: In the home * Anything relating to the human home A home, or domicile, is a sp ...

bobcat
,
red Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength Image:dominant wavelength.png, frame, Dominant/complementary wavelength example on the CIE color ...

red
and
gray fox The gray fox (''Urocyon cinereoargenteus''), or grey fox, is an omnivorous An omnivore () is an animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animal ...
,
ringneck pheasant The common pheasant (''Phasianus colchicus'') is a bird in the pheasant Pheasants () are birds of several genera within the subfamily (biology), subfamily Phasianinae, of the family (biology), family Phasianidae in the order (biology), orde ...
,
bobwhite ''Colinus'' is a genus of birds in the New World quail family, Odontophoridae. Members of the genus are commonly known as bobwhites. Species Extant species Fossil species * †''Colinus eatoni'' * †''Colinus suilium'' Brodkorb 1959 * †''Co ...
, and
red-tailed hawk The red-tailed hawk (''Buteo jamaicensis'') is a bird of prey that breeds throughout most of North America, from the interior of Alaska and northern Canada to as far south as Panama and the West Indies. It is one of the most common members withi ...

red-tailed hawk
, some of which were introduced or encouraged by Euro-American settlers. Woodland species are also on the rise in the Loess Hills as the suppression of fire has led to an increase in habitat for forest-dwelling species. Fauna more typical of the pre-settlement Loess Hills, such as the prairie rattlesnake, great plains skink, plains pocket mouse, ornate box turtle and American spadefoot toads, spadefoot toad, are becoming rare and even endangered due to habitat fragmentation as a result of increased development and suppression of fire in prairie remnants and oak savannas. Species such as bobcat have been rebounding, and mountain lions have been recorded in Southwest Iowa in the last decade. Historically, fauna also included American bison, greater prairie chicken, prairie chicken, mule deer, elk, and gray wolf; these were extirpated by the late nineteenth century. The Missouri River valley had historically been a major migration corridor for birds, however, the channelization of the river and destruction of wetlands has led to a marked decline. The corridor still boasts one of the best areas to view raptor migrations on the continent. As air masses move off the Great Plains, they sink into the Missouri River valley. The prevailing winds across the floodplain then hit the sharp rise of the Loess Hills, creating thermal updrafts that raptors use to make their way to and from breeding grounds. Raptors can often be viewed forming "kettles", where many birds will create a funnel-like formation as they utilize the same thermal. Typical species found during the months from September to December include
red-tailed hawk The red-tailed hawk (''Buteo jamaicensis'') is a bird of prey that breeds throughout most of North America, from the interior of Alaska and northern Canada to as far south as Panama and the West Indies. It is one of the most common members withi ...

red-tailed hawk
, sharp-shinned hawk, peregrine falcon, ferruginous hawk, Swainson's hawk, Cooper's hawk, osprey, northern harrier, American kestrel, and bald eagle. In all, 20 species of raptor have been identified in a single season since the Hitchcock Nature Center HawkWatch started, with a record count of 16,000 birds in one season in 2005. Broken Kettle Grasslands Preserve in the northern Loess Hills is home to Iowa's only population of nesting black-billed magpies and home to the last remaining known population of prairie rattlesnake in Iowa.


Recreation and public lands

The Loess Hills Scenic Byway affords many scenic views from Westfield, Iowa, and to Hamburg, Iowa, Hamburg. While much of the landscape is held in private ownership, thousands of acres of public land exist in state and county parks, wildlife areas and preserves. The Nature Conservancy also owns several preserve areas in the Hills which are open to the public, including Broken Kettle Grasslands Preserve—the largest contiguous tract of native prairie left in Iowa. The List of Iowa state forests, Loess Hills State Forest is located in west-central Iowa in Harrison County, Iowa, Harrison and Monona County, Iowa, Monona counties. It comprises four units totaling , and offers hiking, backpacking, picnicking, and fishing opportunities. Preparation Canyon State Park, located near Pisgah, Iowa, Pisgah in Monona County, Iowa, Monona County, is a less developed park in the middle of the Loess Hills State Forest. It has including what was once the Mormon village of Preparation, Iowa, Preparation. Backpacking trails lead to hike-in campsites. Two major state parks anchor the north and south end of the range—Waubonsie in the south and Stone in the north, both offer camping and a variety of other amenities. Hitchcock Nature Center is operated by the Pottawattamie County, Iowa, Pottawattamie County Conservation Board and features a lodge with raptor viewing platform and observation tower, from which one has striking views of the Hills, the
Missouri River The Missouri River is the longest river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its ...
valley, and the skyline of downtown Omaha, Nebraska. Hike-in camping is also available at this location. Two National Natural Landmarks are located in the Loess Hills. The Little Sioux/Smith Lake Site contains and is perhaps the best example of the unique topography produced by large deposits of loess soil. The Turin Site of the Loess Hills National Natural Landmark is located just outside Turin and also contains the Turin Man prehistoric archeological site.


Human history

The Loess Hills have a rich archaeological heritage. The hills around Glenwood, Iowa, Glenwood, in Mills County, Iowa, Mills County, were inhabited by the Glenwood culture, an eastern extension of the Nebraska Phase of the Woodland period. The Glenwood Culture lived in the area from roughly 900 A.D. to 1300 A.D. and built hundreds of earth lodges in the region, farming the rich valley bottoms and cultivating native plants from the surrounding hills. An earth lodge replica has been reconstructed in Glenwood Lake Park, and the Mills County Museum, also located at the park, houses an excellent collection of artifacts collected by renowned amateur archeologist Paul Rowe. The city of Council Bluffs, Iowa (originally "Kanesville") derives its name from the hills based on the Lewis and Clark Expedition, Lewis and Clark first formal "council", or meeting, with Native Americans in the United States, Native Americans in 1804, although the meeting with the Otoe tribe, Oto and Missouria, Missouri tribe actually took place on the Nebraska side of the Missouri River at Fort Atkinson (Nebraska), Fort Atkinson. Charles Floyd (explorer), Sgt. Charles Floyd, the only fatality of the Lewis and Clark Expedition, is buried on a bluff in the Loess Hills in what is now Sioux City, Iowa. In 1853, Mormons, Mormon Elder (Latter Day Saints), elder Charles B. Thompson split off from the main wagon train to Utah. He initially led 50 to 60 Mormon families to Council Bluffs, Iowa, Kanesville. Thompson and a few other men then chose an area called Monona ("peaceful valley"), where they founded the town of Preparation, Iowa, Preparation, named for "School of Preparation for the afterlife, Life Beyond." Realizing the valley's wealth as a farming region, Thompson used his newspaper to report a message "from a spirit" directing the Mormon people to turn over all deeds and possessions to Thompson, who changed his name to "Father Ephraim". In 1856, the people asked for the return of their property; Thompson refused and they decided to lynching, lynch him. Thompson escaped the mob by hiding in an attic in Onawa, Iowa, Onawa. He then fled Iowa. On August 12, 1859, Abraham Lincoln ascended the hills at Cemetery Hill at Fairview Cemetery in Council Bluffs while being briefed on possible locations for the First Transcontinental Railroad.


Other loess landscapes

Loess soil also forms the Arikaree Breaks in northwest Kansas, and the Mississippi-Yazoo "Bluff Hills" near Vicksburg, Mississippi. A large region of
Nebraska Nebraska () is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspaper ...

Nebraska
to the south and east of the Sandhills is covered with loess. Deep loess deposits are also found in the Rhine River valley in Germany. Crowley's Ridge in southeastern
Missouri Missouri is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspaper in ...

Missouri
and northeastern and eastern Arkansas is made up of loess soil. The word ''loess'' is derived from the German for "loose or crumbly."


See also

*Loess Plateau *Yunnan–Guizhou Plateau


References


External links


Loess Hills Scenic BywayGeology USGSLoess Hills State Forest
{{authority control Landforms of Iowa Hills of Missouri Hills of the United States Missouri River National Natural Landmarks in Iowa Regions of Iowa Regions of Missouri