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Physiography of Tennessee

compiled by Kevin E. Smith

Centrally located in the interior southeastern United States, Tennessee has a land area of 26,443,500 acres or 41,318 square miles. The topography of Tennessee is among the most varied in the United States, ranging from wide level river bottoms in the west to high mountain peaks in the east, with valleys, plateaus, basins, and other features in between. Physiographic regions are important background knowledge for archaeologists, due to the often extensive interaction between human culture and the local environment.

Nine physiographic regions of Tennessee are described following.

[ Unaka Mtns ] [ Valley&Ridge ] [ Plateau ]
[ E Highland Rim ] [ C. Basin ] [ W Highland Rim ]
[ W Valley ] [ Coastal Plain ] [ Mississippi Valley ]

UNAKA MOUNTAINS

The Unaka Mountains are a portion of the Appalachian Mountains in Tennessee (called the Blue Ridge elsewhere). The Unakas include the Great Smokies (ranges included within the Great Smoky Mountains National Park), and such mountains as Chilhowee, English, Bean, Meadow Creek, Holston, Starr, Roan and others (Miller 1974:3). These mountains are characterized by rugged terrain, heavily forested slopes, and rushing streams with waterfalls. Interspersed among these ranges are large coves, such as Cades, Wear, Tuckaleechee, and Bumpass. The valleys range in elevation from about 1000 feet above sea level in the south to 1500 feet in the north, and several peaks are more than 6000 feet in elevation.

The Unaka Mountains lie in the northwestern portion of the Blue Ridge subdivision of the Southern Appalachian Mountains. Mountains in this region consist of heavily forested ridges with rugged terrain and many rushing streams (Miller 1974:3). Elevations in the valleys range from 1000 feet AMSL in the south to 1500 feet in the north with ridges and peak s reaching between 2500 and 6300 feet. The Unaka range, the crest of which forms the Tennessee-North Carolina state line contains many westwardly oriented ridges separated by steep narrow valleys, although the general trend is northwesterly. Major streams such as the French Broad, Ocoee, and Watauga Rivers tend to have cut channels through rocks with the least resistance.

Mountains in the Northern part of the range are composed of Lower Paleozoic limestone, dolomites and shale with exposures of Precambrian igneous and metamorphic basement rocks such as tuff, rhyolite, granite, schist and quartzite. The many formless mountains to the south along the state line are mainly composed of Precambrian sedimentary and metamorphic sandstone, conglomerate, arkose and siltstone. These include the Great Smoky Mountains (King and Ferguson 1960:9). Soils of the uplands are severely leached and are resultingly acidic and low in fertility, especially those overlying igneous formations. Since many of the soils in this region developed under a heavy forest cover, they are relatively low to medium in organic matter and light colored. Valley soils are usually alluvial and moderately to excessively drained (USDA 1953b:9).

The Unaka Mountains are part of the Southern Appalachian section of the Oak-Chestnut Forest region. The lower slopes of the Unaka range are mostly dominated by Oak-chestnut and mixed mesophytic forests including such species as buckeye, sugar maple, yellow birch, beech, and hemlock. The higher slopes are occupied by beech-maple and spruce-fir communities with grassy and rhododendron balds occurring above 5500 feet. In many other areas, including the Great Smoky Mountains, valleys and flats at low elevations support mixed deciduous-coniferous and spruce-fir communities (Braun 1950:201,214-215).

The climate of the region varies considerably between the high and low elevations. Summers are normally hot in the valleys and cooler in the higher elevations. Average yearly temperatures range from 50 in the mountains to 55 degrees Fahrenheit in the valleys. Yearly precipitation ranges from about 45 to 50 inches, much of it occurring in the summer months. Snowfall occurs frequently at higher elevations (USDA 1953b:6, 1955:8, 1956:10).

VALLEY AND RIDGE

The Valley and Ridge is sometimes referred to as the Valley of East Tennessee. Numerous elongate ridges and intervening valleys, all trending in a northeast-southwest direction, characterize this physiographic region. This orientation is the result of folding and fracturing during a mountain building episode 230 to 260 million years ago.

The Valley and Ridge extends from the Unakas on the east to the escarpment of the Cumberland Plateau on the west. The most prominent ridges are to the north -- Clinch and Powell Ridges, and Bays Mountain. To the south the highest and longest ridge is Whiteoak Mountain, between Chattanooga and Cleveland. These ridges range in elevation from 1495 feet (Whiteoak Mountain) to 3097 feet (Bays Mountain). Valleys to the north average about 1000 feet in elevation and to the south about 750 feet.

The Valley and Ridge physiographic province occurs in Tennessee as a section of a long narrow belt of the Folded Appalachian geosyncline (Southern Appalachian Mountains) and ranges in width from 100 to 30 miles from north to south (Fenneman 1938:265). Folding and fracturing during late Paleozoic times resulted in the northeast-southwest orientation of ridges and intervening valleys, which are underlain by respectively resistant and weaker rocks. Valley elevations are about 750 feet AMSL in the south and 1000 feet further north. Ridges generally reach to about 1500 feet with some mountains approaching 3000 feet. The eastern escarpment of the Cumberland Plateau and the Blue Ridge subdivision (Unaka Mountains) of the Appalachian Foldbelts mark the boundaries of this region. Bedrock is shown through folding activity to be composed of Ordovician and Cambrian limestone, shale, and sandstone with outcrops of Devonian and Mississippian limestone and chert in northern areas (Miller 1974:3). Cave development occurs at lower elevations.

Streams generally follow the narrow valley floors or cut across the strike of the ridges. The Tennessee River flows southwest through the region. Principal feeders from the north are the Clinch, French Broad, and Holston Rivers. Major tributaries from the east are the Hiwassee and Little Tennessee Rivers.

The Valley and Ridge section is located in the Ridge and Valley Section of the Oak-Chestnut Forest region. Ridge crests support such species as white and red oak, sour gum, sassafras, and chestnut. Lower mountain slopes contain mixed mesophytic communities of beech, white oak, and buckeye. Valleys floors are dominated by white oak and occasionally tulip and hickory. In the large valleys to the south, there occurs a gradual change from an oak-chestnut to an oak-pine type forest (Braun 1950:232, 238).

The climate of this region varies locally depending on topography and prevailing winds, but is generally characterized by warm summers and short, mild winters. The average yearly temperature ranges from 50 to 60 degrees Fahrenheit north to south. Rainfall is abundant in winter and spring, averaging between 45 and 55 inches per year. Fall is typically the driest season (USDA 1953c:6, 1958:2, and 1979:2).

CUMBERLAND PLATEAU

The Cumberland Plateau is part of the Appalachian Plateau Physiographic Province as described in Fenneman 1938, which consists of a tableland region that extends from western Pennsylvania to northeastern Alabama. The portion of the Plateau that lies in Tennessee forms a striking cuesta thirty to fifty-five miles wide and averages from five hundred to over a thousand feet higher than the adjacent Valley and Ridge to the east and the Interior Low Plateau to the west. This elevated tableland is the result of highly resistant caprock of Pennsylvanian age sandstone and conglomerate.

Because of its striking geologic and physiographic features, the Cumberland Plateau has long been accorded regional distinction by geographers (Fenneman 1938; Thornbury 1965). The Cumberland Plateau is part of the Appalachian Plateau Physiographic Province as described by Fenneman 1938), which consists of a tableland region that extends from western Pennsylvania to northeastern Alabama. The portion of the Plateau that lies in Tennessee forms a striking cuesta thirty to fifty-five miles wide and averages from five hundred to over a thousand feet higher than the adjacent Ridge and Valley Province to the east and the Interior Low Plateau's Province on the west. This elevated tableland is the result of highly resistant caprock of Pennsylvanian age sandstone and conglomerate that has impeded the erosional processes exposing the limestone regions to the east and west. The Plateau is considered a true peneplain, exhibiting a broad, undulating surface submaturely dissected by young valleys whose steepness and depth increase toward its edges (Fenneman 1938:337).

High escarpments having an average elevation of approximately 900 feet above sea level mark the eastern and western boundaries of the Plateau. On the east the escarpment is a high, almost unbroken linear scarp that in places rises a thousand feet above the Ridge and Valley region. This portion of the Plateau is known as Walden's Ridge. The western escarpment is less pronounced and very irregular due to the number of deeply entrenched drainages that have sapped the caprock at its edges carving deep valleys into the underlying limestone and leaving numerous sandstone capped outliers isolated from the main body of the Plateau. Although the northern and southern boundaries of the Plateau are less pronounced, the northern portion of the region consists of the Cumberland Mountains with elevations exceeding 3000 feet above sea level (Miller 1974:3). The selection of a northern boundary for the Cumberland Plateau is arbitrary, the division being based on the greater degree of dissection of the Plateau to the north (Fenneman 1938:333).

The most uniform area of the Plateau includes all formations of Pennsylvanian age that are bounded by the escarpment of Walden's Ridge and Cumberland Mountains on the east, by the Tennessee River on the south, by the Cumberland River on the north, and by the continuous escarpment along the western edge of the caprock. These boundaries delineate an upland area of approximately 13,000 square kilometers, which is relatively uniform with respect to salient characteristics of physiography, geology, hydrology, and the biotic and edaphic factors typical of the submaturely dissected Cumberland Plateau. In this manner a relatively homogenous study unit is defined in which the influence of environmental attributes may be expected to have a direct and observable influence on the structure of human adaptive systems (Ferguson and Pace 1981:2).

Geologically, the Plateau is formed from horizontal rock strata; however, the development of several structural folds and fault systems has had a pronounced effect on local topography. The most obvious of these systems is along the eastern escarpment, particularly in northern Tennessee and southern Kentucky, where a great block fault forms the structural basis for the Cumberland Mountains, an area of pronounced elevation and relief. Likewise the Crab Orchard Mountains of the central Plateau are the remainder of an anticlinal system that elsewhere developed into the Sequatchie Valley.

The Sequatchie Valley extends 200 miles from the east-central portion of Tennessee into northeastern Alabama (Sterns 1954). Throughout its length the valley is almost perfectly straight. The valley is bound latitudinally by the notched escarpments of Walden's Ridge to the east and the Cumberland Plateau to the west (Elder 1958:2). The Sequatchie Valley is considered a part of the Cumberland Plateau and represents the most striking topographic feature of the Plateau region (Thornbury 1965:148). Along much of its length, the valley is representative of an asymmetrical anticlinal fold. This structure begins at the northern portion of the valley in the Crab Orchard Mountains as a nearly symmetrical fold involving Pennsylvanian sandstones and conglomerates. The fold is breached just south of the Crab Orchard Mountains in a karst basin known today as Grassy Cove.

Drainage of the Plateau (including the Sequatchie Valley) is characteristically dendritic in pattern. Major drainage systems of the Plateau may be divided into two principal groups, consisting of those that are tributary to the Cumberland River system and those that are tributary to the Tennessee. The Cumberland River tributaries include the Caney Fork, Obey, Wolf, Big South Fork, and Elk Rivers as well as Jellico Creek. Those of the Tennessee River include the Tennessee, Sequatchie, Emory, Clinch, and Elk Rivers as well as Battle Creek (Ferguson and Pace 1981: 3). Several of these drainages actually drain relatively small portions of the Plateau. However, the Emory, Big South Fork, and Caney Fork Rivers drain in excess of 20% of the area defined, a combined total area of over 7000 square kilometers. The drainage of the Big South Fork of the Cumberland River contains approximately 3200 square kilometers of the Plateau or roughly 24% of the total area defined within the study unit.

The Cumberland Plateau is the southern portion of the Appalachian Plateau physiographic province. The topography is that of a true peneplain, generally flat with some moderate undulation (Fenneman 1938:337). Ranging in width from about 30 to 60 miles, the eastern boundary is a large escarpment with an average elevation of about 900 feet AMSL. Elevations on the plateau surface range from 1700 feet to about 2000 feet. The western escarpment rising above the Eastern Highland Rim is irregular and dissected by steep valleys. Two linear valleys, the Elk and Sequatchie, an anticlinal valley, were formed from extensive faulting and folding during a period of Appalachian mountain building. The Cumberland Mountains, with elevations exceeding 3000 feet, occur in the northern part of the region (Miller 1974:3).

The Tennessee River, forming the southeastern boundary of the region, has many east-flowing tributaries that drain the eastern Plateau. These include Falling Water, Mullens, Piney and Suck Creeks and the North Chickamauga River. Tennessee River tributaries include the Battle Creek, and the Clinch, Elk, Emory and Sequatchie Rivers. The region contains the Cumberland River divide and its tributaries, the Big South Fork, Caney Fork, Obey and Wolf Rivers that generally flow west-northwest. A cap of resistant Pennsylvanian sandstone and conglomerate up to 1000 feet thick covers the plateau surface. Much of it consists of the Rockcastle Conglomerate in the north and Sewanee Conglomerate and Gizzard Sandstone in the south. Dissecting the plateau are numerous deep gorges that form prominent cliffs along their perimeters. Paleozoic age limestone, shales, siltstones, and coal that are exposed in gorges and valleys underlie the sandstone cap. Karst development is common where limestone is exposed, with large caves forming generally below 1500 feet.

Soils in the Plateau are chiefly formed from parent material and, consequently, are sandy loams that are fairly well drained. Silt loams and residual clays occur on slopes and valley floors. Loess of western origin is nearly absent from the region (USDA 1981:2).

The Cumberland Plateau falls within the Cumberland and Allegheny section of the Mixed Mesophytic Forest region. It is described as one of the oldest and most complex associations of the eastern deciduous forests. Where the region is deeply dissected, typical dominant species include tulip, poplar, white and red oak, hemlock, basswood, beech, chestnut, and sugar maple. The old peneplain surface is dominated by oak or oak-hickory forest (Braun 1950:39,114).

Because of its higher elevation, the region maintains a temperate climate with average temperatures lower than the adjacent regions. General weather conditions are subject to microclimatic variation between areas. The annual mean temperature is 55 degrees Fahrenheit in the northern Plateau and about 4 degrees higher in the south. Precipitation averages about 50 inches per year, much of it as rain occurring from late winter through early spring. Snowfall averages about 10 inches per year (Ferguson and Pace 1981:7-10).

EASTERN HIGHLAND RIM

The eastern subdivision of the Highland Rim region is characterized by generally undulating terrain except in the flat south-central portion known as the Barrens. About 25 miles in width, the eastern Rim is set apart from the Central Basin by a west-facing dissected escarpment forming a bench with an average elevation of slightly more than 1000 feet (Miller 1974:6). The constituent bedrock is composed primarily of Mississippian, St. Louis, and Warsaw limestone with Fort Payne chert underlain by Chattanooga Shale that forms a large part of the escarpment. Separating the Highland rim from the Cumberland Plateau are steep-walled valleys which are often wide in proportion to their length, largely due to solution (Fenneman 1938:417). The region is more prolific in karst development than the Western Rim, with the southern portion containing extensive cave systems. Major drainages of the region are the Caney Fork and Cumberland Rivers. The Elk River, a tributary of the Tennessee River, drains the southern Eastern Highland Rim.

Most of the region is covered with a silty mantle of loess underlain by residual clays or cherty clay. Where the mantle has been thinned by erosion the clay is red, a typical characteristic of limestone soils with high iron oxide content. Drainage in the region is moderate to good. The colluvial soils of the valley floors are rich in organic matter and are well suited to agriculture (USDA 1963:97).

Similar to the Western Highland Rim, this region is part of the Mississippian Plateau section of the Western Mesophytic Forest region, supporting a mixed oak-tulip-chestnut forest with accessory stands of beech and hemlock. Relic stands of mixed hardwood-white pine occur on some bluffs above streams. The Barrens are closely related with karst topography and were once tall grass prairies (Braun 1950:152-155).

Climate of the eastern Highland Rim is seasonally variable with generally mild winters and warm summers. Rainfall averages between 50 ad 55 inches per year and is heaviest in late winter or early spring. The average yearly temperature is variable from place to place and it about 60 degrees Fahrenheit (USDA 1959a:88, 1972:2).

CENTRAL BASIN

The Central Basin is an elliptical depression surrounded by the Highland Rim. It was formed by the relatively rapid erosion of an uplifted area of bedrock called the Nashville Dome during late Paleozoic times. Approximately 125 miles north-south and about 60 miles east-west, the Basin is subdivided into inner and outer sections. The inner section is generally smooth and gently rolling in contrast to the higher and more deeply dissected outer Basin (Miller 1974:5). The average elevation of the inner Basin is about 600 feet above mean sea level while the average elevation of the outer basin is about 750 feet. Siliceous rocks cap the hills of the latter, reaching heights of 1,300 feet. Major drainages of the region are the westward flowing Cumberland River and the Duck and Elk Rivers flowing northwest and southwest respectively. Two major tributaries of the Cumberland River draining the inner basin are the Harpeth and Stones Rivers. Floodplains of these and other streams are similar in both sections, generally low gradient and meandering (Edwards et al 1974:4). Bedrock is primarily Ordovician limestone, shale and dolomite in the outer Basin with the Mississippian Fort Payne formation overlying Chattanooga shale marking the contact between the Basin and the Highland Rim (Wilson 1949:2). The inner basin is generally covered with limestone of the Stones River formation with patches of bare platy rock and thin topsoil with glade areas supporting red cedar trees. The region is moderate in karst development with many sinkholes and some large caves present, notably in the glade areas.

Soils of the Central Basin are for the most part high in silt content and rich in calcium derived from the parent limestone. Thick deposits of alluvium and colluvium occur in valley floors and loess covers a small part of soils throughout the region. Saline groundwater discharge in some areas has resulted in the formation of salt licks and springs which were utilized during prehistoric and historic times (Edwards et al 1974:115).

The Central Basin lies within the Western Mesophytic forest region and originally supported a forest of large trees. Climax communities including oak, hickory, tulip tree, beech and chestnut occur in hilly areas. Lower hills and flats support hickory, winged elm, hackberry, and blue ash. Deciduous species within the cedar glades are predominantly hickory, oak and sugar maple (Braun 1950:132).

The climate of the region is variable between different elevations and geographic points. The mean annual temperature is 60 degrees Fahrenheit. Rainfall is uniformly distributed, averaging 45 to 55 inches per year with most occurring in late winter or early spring. Fall is typically the driest season (Klippel and Bass 1984:5).

WESTERN HIGHLAND RIM

The Western Highland Rim in Tennessee is the western subdivision of the Highland Rim of the Interior Low Plateau physiographic province. Entirely surrounding the Central Basin, the Highland Rim is characterized by rolling terrain dissected by sharply incised valleys with numerous streams (Fenneman 1938:416). Elevations range from about 700 to 1000 feet above mean sea level with the topography of the southern part generally more level than in the north. Major drainages in the region are the Duck and Buffalo Rivers (tributaries of the Tennessee River), and the westwardly flowing Cumberland River. Underlying bedrock of the region is chiefly Mississippian limestone, chert, shale, and sandstone with exposures of Devonian, Silurian, Ordovician, and Cambrian limestone, chert, and shale. The latter are exposed primarily in the drainages of the Buffalo and Duck Rivers. Karst development features such as caves and sinkholes are present on the northernmost counties of the region (Miller 1974:5).

The well-drained upland and imperfectly drained bottomland soils are predominately sandy clay and gravelly silt loams. Terraces near the bottomlands consist mainly of cherty silt loams and silt loams (USDA 1946:16).

The Western Highland Rim is part of the Mississippian Plateau section of the Western Mesophytic Forest region, where oak forest was formerly predominant. A mixed oak-tulip-chestnut type forest with accessory stands of beech, hickory, and sugar maple occupies the well-drained areas. Poorly drained lowlands contain oak, gum, red maple and beech (Braun 1950:154).

In this region, winters are mild and summers and hot and periodically dry. The yearly average temperature is 60 degrees Fahrenheit with 50 inches of precipitation occurring mostly during the winter and early spring (USDA 1959b:2 and 1975:2).

WESTERN VALLEY

The Western Valley region comprises the channel, floodplain, and terraces of the northward flowing Tennessee River, along with the West Tennessee Uploads east of the Tennessee Divide. The uplands section, is dissected and hilly, and is 20 to 30 miles wide with an average elevation of about 500 feet above mean sea level. Major drainages flowing into the Tennessee River are the Beech, Big Sandy, and White Oak Rivers (Miller 1974:7). Sandy Cretaceous underlies the area and Eocene deposits. Soils are generally well-drained sandy loams enriched by a thin mantle of loess (USDA 1960a:7).

The Tennessee Valley proper is in places as wide as 20 miles with the floodplain portion ranging in width from 3.5 miles near the Alabama state line to 1.5 miles in Benson and Houston counties in the mid-northern part of the state. Elevation of the floodplain ranges from about 350 to 400 feet above mean sea level. The dissected meandering river valley, with ridge crests of the West Tennessee Uplands and Western Highland Rim rising 200 to 300 feet above the floodplain on their side, contains remnants of alluvial terraces and natural levees. Considerable erosion of these features has taken place since the impounding of Kentucky Lake Reservoir by the Tennessee Valley Authority (Miller 1974:7). Major tributaries of the river in the Western Valley are the Big Sandy and Duck Rivers.

Pleistocene and recent alluvial deposits of sand, silt, clay, and gravel up to 60 feet thick cover the valley floor. The floodplain and adjacent ridges are underlain chiefly by cherty Devonian-Mississippian Fort Payne limestone and Chattanooga Shale (Hardeman 1966). Soils of the floodplain and terraces are primarily fine sandy loams and silt loams. The surrounding uplands soils are excessively drained sandy clay loams formed from cherty limestone and Coastal Plain alluvium (USDA 1948:15 and 1960b:123).

The bluffs of the West Tennessee Uplands comprise the western boundary of the Mississippian Plateau section of the Western Mesophytic Forest region. Forests in the valley are of a mixed white oak-hickory type with an abundance of species in the southern part. Other species occur mainly in ravine communities and include beech, tulip tree and sugar maple (Braun 1950:154-156).

Short mild winters and warm summers that are hotter in the southern portion of the state generally characterize the climate of the region. The mean yearly temperature is between 58 and 60 F with 52 inches of precipitation that is heaviest during the winter and early spring months.

COASTAL PLAIN

The West Tennessee Coastal Plain is defined as the area west of the Tennessee River divide and to the east of the loess hills that flank the Mississippi River Valley.

The Coastal Plain region, a portion of the East Gulf Coastal Plain (Fenneman 1938) is an area of relatively low relief. Herein, a slight departure from Fenneman's (1938) division has been made. While Fenneman includes both the West Tennessee Uplands and the West Tennessee Plains in this region, the West Tennessee Uplands east of the Tennessee River divide has been included in the Western Valley. The uplands grade into the extensive West Tennessee Plain that is less hilly and nearly flat in some areas. Major drainages flowing west to the Mississippi River are the Forked Deer, Hatchie, Loosahatchie, Obion and Wolf Rivers. Deposits of loess up to 65 feet thick underlie the West Tennessee Plain, with the thinnest part located in the east where it merges with loessic Upland soil. This formation overlies Eocene sand and clay deposits (Blythe et al 1975:4). The Plain slopes gently westward extending to and including the Loess Hill Bluffs (the belt of hills that rise 1250 to 250 feet above the Mississippi River floodplain). The Loess Hill bluffs range in width from 5 to 15 miles and extend north-south from Reelfoot Lake to Memphis (Fenneman 1938:80).

The Coastal Plain is included in the Mississippian Embayment section of the Western Mesophytic Forest Region. The loess hills and upland areas consist of a mixed mesophytic oak-hickory forest. Other species include yellow pine, tulip tree, white ash, dogwood, wild black cherry, persimmon and mulberry. Bottomlands in the region support swamp forests which include cypress, elm, ash and cottonwood (Braun 1950:158).

Relatively mild winters and hot summers characterize the climate. Average yearly rainfall is about 50 inches with most occurring in late winter and early spring. The yearly mean temperature is 60 degrees Fahrenheit. (USDA 1953a:8, 1960a:2).

MISSISSIPPI RIVER VALLEY

The Mississippi River Valley includes both the alluvial floodplain and the adjacent loess bluffs that flank the east side of the Mississippi River for much of its length. The Mississippi River alluvial valley is as much as 5.5 km wide in the study area, with the Reelfoot Lake Basin being the most prominent feature. Numerous oxbow lakes are presents, and the meandering of the Mississippi River have played a major role in the deposition preservation, and destruction of archaeological sites and remains. The loess bluffs rise sharply above the valley floor, reaching heights of over 40 m and slope gently eastward where they merge with the Coastal Plain.

The Mississippi River floodplain ranges in width from 15 miles near the Reelfoot Lake basin to about five miles in the vicinity of Memphis and rises from 185 to 230 feet above mean sea level. The line of hill slopes, forming the eastern boundary, is known as the Loess Hill Bluffs, composed of silty Pleistocene loess up to 80 feet thick and underlain by fluvial deposits of sand, gravel, and Eocene clay and sandstone of the Jackson formation (Blythe et al 1975:67). The floodplain exhibits topographic features such as cutoffs, oxbow lakes and natural levees formed by activities of the meandering river channel which ceased downcutting about 9,000 year ago (Phillips et al 1951:7).

Soils of the bottomlands generally have been transported from the great central plains and prairies. They are rich in organic matter and are among the most fertile soils in the state. They range from excessively drained sandy loams on the first bottoms to poorly drained clays on the low floodplains (USDA 1970:6).

The Mississippi River Valley in Tennessee forms the contact between the Southeastern Evergreen and Western Mesophytic Forest regions. Swamp forests of the alluvial plain consist mainly of bald cypress and water tupelo with occasional red and silver maple, pecan and water ash. The hardwood stands of higher elevations include sweet gum, elm, sassafras, hackberry, and many species of oak. The loess hills are part of the Western Mesophytic forest and are dominated by oak-hickory forest which includes other trees such as beech, tulip, cucumber, sugar maple, and basswood (Braun 1950:159-160 and 292-293).

The climate of the region is characterized by generally mild winters and hot summers with an average annual temperature of 60 degrees Fahrenheit. Rainfall is abundant, averaging about 48 inches per year, occurring mostly in winter and early to late spring (USDA 1969:2 and 1970:2).


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