The Highland Rim is a geographic term for the area in

Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...

North Alabama North Alabama is a region of the U.S. state of Alabama. Several geographic definitions for the area exist, with all descriptions including the nine counties of Alabama's Tennessee Valley region. The North Alabama Industrial Development Associ ...

, and

Kentucky Kentucky (, ), officially the Commonwealth of Kentucky, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Illinois, Indiana, and Ohio to the north, West Virginia to the ...

which surrounds the Central Basin. The Central Basin is a geological

dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

which has subsequently fractured and eroded to produce a basin. The Highland Rim is a

cuesta A cuesta () is a hill or ridge with a gentle slope on one side, and a steep slope on the other. In geology, the term is more specifically applied to a ridge where a harder sedimentary rock overlies a softer layer, the whole being tilted somew ...

surrounding the basin, and the border where the difference in elevation is sharply pronounced is an

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. Due to the similarity, the term '' scarp'' may mistakenly be incorrectly used inte ...

. Ther feature continues well into

Southern Indiana Southern Indiana is a geographic and cultural region that generally comprises the southern third of the U.S. state of Indiana and borders the states of Illinois to the west, Kentucky to the south, and Ohio to the east. Spanning the state's southe ...

even up as far as

Central Indiana The geography of Indiana comprises the physical features of the land and relative location of U.S. State of Indiana. Indiana is in the north-central United States and borders on Lake Michigan. Surrounding states are Michigan to the north and no ...

as the

Indiana Uplands The Indiana Uplands or the Hoosier Uplands are a geographical region in south-central Indiana. On a topographical map the Indiana Uplands begin slightly north of the city of Martinsville, Indiana and continue south to the Ohio River. The descripti ...

Geology and physiography

The Highland Rim is a physiographic section of the larger

Interior Low Plateaus The Interior Low Plateaus are a physiographic region in eastern United States. It consists of a diverse landscape that extends from north Alabama across central Tennessee and Kentucky into southern Illinois, Indiana, and Ohio. Its natural commun ...

province, which in turn is part of the larger

Interior Plains The Interior Plains is a vast physiographic region that spreads across the Laurentian craton of central North America, extending along the east flank of the Rocky Mountains from the Gulf Coast region to the Arctic Beaufort Sea. In Canada, it ...

physiographic division. Most of the Highland Rim is located in U.S. EPA

Ecoregion An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...

71, Interior Plateau, which is a part of the Eastern Temperate Forest. The sections of the Highland Rim are referred to the four cardinal directions, e.g., "Northern Highland Rim", etc. The Highland Rim is rather continuous and any division of it, including the ones made below, are somewhat arbitrary. The term "highland" here is relative: it is certainly higher than the basin it surrounds, but it nonetheless is seldom at an elevation above above sea level and never more than about above sea level except where interrupted, primarily to the southeast, by outliers of the

Cumberland Plateau The Cumberland Plateau is the southern part of the Appalachian Plateau in the Appalachian Mountains of the United States. It includes much of eastern Kentucky and Tennessee, and portions of northern Alabama and northwest Georgia. The terms " Al ...

. With the exception of a few broad stream bottoms, the land is characterized by ridges and valleys with a few fairly low hills. The entire region is well watered with many perennial streams. There are occasional waterfalls which sometimes delineate the Highland Rim from the Central Basin which it surrounds.

Western Highland Rim

The Western Highland Rim is encountered a few miles west of Nashville and extends to the western valley of the

Tennessee River The Tennessee River is a long river located in the Southern United States, southeastern United States in the Tennessee Valley. Flowing through the states of Tennessee, Alabama, Mississippi, and Kentucky, it begins at the confluence of Fren ...

. The area is hilly, ranging from about 400 to 1000 feet in elevation, and is bisected by the

and the

Cumberland River The Cumberland River is a major waterway of the Southern United States. The U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed June 8, 2011 river drains almost of southern Kentucky and ...

valleys. Underlying bedrock of the region is chiefly

Mississippian Mississippian may refer to: * Mississippian (geology), a subperiod of the Carboniferous period in the geologic timescale, roughly 360 to 325 million years ago * Mississippian cultures, a network of precontact cultures across the midwest and Easte ...

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

, and

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

with exposures of

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ...

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

, and

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

limestone, chert, and shale. In the northern part of the Western Highland Rim,

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water ...

s readily occur in an area with a southern extension of the Pennyroyal plateau of Kentucky, where the

karst Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. Ther ...

is best developed on the

St. Louis Limestone The St. Louis Limestone is a large geologic formation covering a wide area of the midwest of the United States. It is named after an exposure at St. Louis, Missouri. It consists of sedimentary limestone with scattered chert beds, including the ...

and the Ste. Genevieve Limestone. Some farming is done in the flatter interfluves, and in stream and river valleys.

Eastern Highland Rim

The Eastern Rim rises approximately fifty miles east of Nashville and is bordered to its east by even higher terrain, the

. Erosion has exposed carbonate bedrock of Late

Paleozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

age. These carbonate rocks contain variable amounts of chert and are often interbedded with fine grained clastic rocks. As a result, these rocks are more resistant to erosion than the underlying purer limestones of the Lower (Early) Paleozoic. The geology is diverse and is typically limestone at valley floors (around elevation) and sandstone on ridges (to around 1,000 feet). The constituent bedrock is composed primarily of

aged

St. Louis St. Louis ( , sometimes referred to as St. Louis City, Saint Louis or STL) is an independent city in the U.S. state of Missouri. It lies near the confluence of the Mississippi and the Missouri rivers. In 2020, the city proper had a populatio ...

, and

Warsaw Warsaw, officially the Capital City of Warsaw, is the capital and List of cities and towns in Poland, largest city of Poland. The metropolis stands on the Vistula, River Vistula in east-central Poland. Its population is officially estimated at ...

s with Fort Payne chert underlain by

Chattanooga Shale The Chattanooga Shale is a geological formation in Alabama, Arkansas, Georgia (U.S. state), Georgia, Kansas, Kentucky, Missouri and Tennessee. It preserves conodont fossils dating to the Devonian period. It occurs mostly as a subsurface geologic f ...

that forms a large part of the escarpment. This area is flatter than the Western Rim, characterizable as tablelands of moderate relief combined with irregular

plains In geography, a plain, commonly known as flatland, is a flat expanse of land that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, an ...

Northern Highland Rim

The Northern Highland Rim is encountered a few miles north of Nashville and extends to the

border, and the region of Kentucky adjacent to it called the Pennyroyal is largely a continuation of it under another name as is the

, located to the north of the

Ohio River The Ohio River () is a river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing in a southwesterly direction from Pittsburgh, Pennsylvania, to its river mouth, mouth on the Mississippi Riv ...

Southern Highland Rim

For the most part the Southern Rim is the farthest from Nashville, rising at some points just a few miles north of the border with

Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...

. The landforms are continuous with those in adjacent portions of Alabama, although perhaps the most spectacular landforms of any portion of the Rim are to be found there. The stratigraphy of the Southern Highland Rim is primarily composed of flat-lying limestones, dolomites, and shales, and to a much lesser extent, of cherts,

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

s, and very fine grained to conglomeratic sandstones.

References

{{WikidataCoord, display=t Regions of Tennessee Plateaus of the United States Landforms of Tennessee Physiographic sections