Physiographic regions of the U.S. East Coast Courtesy of USGS See:legend

The geology of the Appalachians dates back to more than 480 million years ago. A look at rocks exposed in today's Appalachian mountains reveals elongate belts of folded and thrust faulted marine sedimentary rocks, volcanic rocks and slivers of ancient ocean floor. Strong evidence that these rocks were deformed during plate collision. The birth of the Appalachian ranges marks the first of several mountain building plate collisions that culminated in the construction of the supercontinent Pangea with the Appalachians near the center. from http://tapestry. ... There are eight distinct U. S. physiographic region within the continental United States. ... The Appalachian Mountains are a system of North American mountains running from Newfoundland and Labrador, Canada to Alabama in the United States, although the northernmost mainland portion ends at the Gaspé Peninsula of Quebec. ... Fold or folding may refer to: fold (geology) folding, in poker, is the act of withdrawing from a hand rather than meeting the bet folding ingredients together is a cooking technique protein folding origami, the art of paper folding pattern welding, the folding of metal This is a disambiguation page... A thrust fault is a particular type of fault, or break in the fabric of the Earths crust with resulting movement of each side against the other, in which one side is pushed up relative to the other and somewhat over it. ... Two types of sedimentary rock: limey shale overlaid by limestone. ... Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... Ophiolites are sections of oceanic lithosphere that have been uplifted or emplaced to be exposed within continental crustal rocks. ... Plate tectonics (from the Greek word for one who constructs, τεκτων, tekton) is a theory of geology developed to explain the phenomenon of continental drift, and is currently the theory accepted by the vast majority of scientists working in this area. ... Mountain building is when mountains develop out of previously lower terrain, or even seas. ... A supercontinent is a mass of land comprising more than one continental core, or craton. ... Map of Pangæa Pangaea (Greek for all lands) is the name Alfred Wegener used to refer to the supercontinent that existed during the Mesozoic era, before the process of plate tectonics separated the component continents. ...

During the earliest Paleozoic Era, the continent that would later become North America straddled the equator. The Appalachian region was a passive plate margin, not unlike today's Atlantic Coastal Plain Province. During this interval, the region was periodically submerged beneath shallows seas. Thick layers of sediment and carbonate rock was deposited on the shallow sea bottom when the region was submerged. When seas receded, terrestrial sedimentary deposits and erosion dominated. The Paleozoic is a major division of the geologic timescale, one of four geologic eras. ... World map showing location of North America A satellite composite image of North America North America is a continent in the northern hemisphere, bounded on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the south by the Caribbean Sea, and on the west... The equator is an imaginary line drawn around a planet, halfway between the poles. ... The Atlantic Coastal Plain is the rather flat stretch of land that borders the Atlantic Ocean (including the Gulf of Mexico). ... Carbonate rocks are a class of sedimentary rocks composed primarily of carbonates. ...

During the middle Ordovician Period (about 440-480 million years ago), a change in plate motions set the stage for the first Paleozoic mountain building event (Taconic orogeny) in North America. The once quiet, Appalachian passive margin changed to a very active plate boundary when a neighboring oceanic plate, the Iapetus, collided with and began sinking beneath the North American craton. With the birth of this new subduction zone, the early Appalachians were born. The Ordovician period is the second of the six (seven in North America) periods of the Paleozoic era. ... Illustration of the Taconic orogeny The Taconic orogeny was a great mountain building period that perhaps had the greatest overall effect on the geologic structure of basement rocks within the New York Bight region. ... The Iapetus Ocean was an Ocean that existed in the Southern Hemisphere between Scotland, England and Scandinavia between 400 and 600 million years ago. ... A craton is an old and stable part of the continental crust that has survived the merging and splitting of continents and supercontinents for at least 500 million years. ... Categories: Geology stubs | Plate tectonics ...

Along the continental margin, volcanoes grew, coincident with the initiation of subduction. Thrust faulting uplifted and warped older sedimentary rock laid down on the passive margin. As mountains rose, erosion began to wear them down. Streams carried rock debris downslope to be deposited in nearby lowlands. A volcano is a geological landform (usually a mountain) where magma (rock of the earths interior made molten or liquid by high pressure and temperature) erupts through the surface of the planet. ... Look up Erosion in Wiktionary, the free dictionary Severe soil erosion in a wheat field near Washington State University, USA. Eroded paddock, Australia Detail of erosion Erosion is the displacement of solids (soil, mud, rock, and so forth) by the agents of wind, water, ice, movement in response to gravity...

This was just the first of a series of mountain building plate collisions that contributed to the formation of the Appalachians. Mountain building continued periodically throughout the next 250 million years (Caledonian, Acadian, Ouachita, Hercynian, and Allegheny orogenies). Continent after continent was thrust and sutured onto the North American craton as the Pangean supercontinent began to take shape. Microplates, smaller bits of crust, too small to be called continents, were swept in, one by one, to be welded to the growing mass. The Acadian orogeny is a middle Paleozoic deformation, especially in the northern Appalachians, between Alabama and Newfoundland. ... A terrane in paleogeography is an accretion that has collided with a continental nucleus, or craton but can be recognized by the foreign origin of its rock strata. ...

By about 300 million years ago (Pennsylvanian Period) Africa was approaching North American craton. The collisional belt spread into the Ozark-Ouachita region and through the Marathon Mountains area of Texas. Continent vs. continent collision raised the Appalachian-Ouachita chain to lofty, Himalayan-scale ranges. The massive bulk of Pangea was completed near the end of the Paleozoic Era (Permian Period ) when Africa (Gondwana) plowed into the continental agglomeration, with the Appalachian-Ouachita mountains near the core. The Pennsylvanian was also an Amtrak line until November 1, 2004. ... Africa is the worlds second-largest continent and 3rd most populous . ... This article is about the Ozark Plateau. ... The Ouachita Mountains are a mountain range located in Arkansas and Oklahoma. ... The Himalaya is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau. ... The Permian is a geologic period that extends from about 280 to 248 million years before the present (mya). ... Pangea broke into the two supercontinents, Laurasia and Gondwana The southern supercontinent Gondwana (originally Gondwanaland) included most of the landmasses which make up todays continents of the southern hemisphere, including Antarctica, South America, Africa, Madagascar, India, Arabia, Australia-New Guinea and New Zealand. ...

Pangea began to break up about 220 million years ago, in the Early Mesozoic Era (Late Triassic Period). As Pangea rifted apart a new passive tectonic margin was born and the forces that created the Appalachian, Ouachita, and Marathon Mountains were stilled. Weathering and erosion prevailed, and the mountains began to wear away. The Mesozoic is one of three geologic eras of Phanerozoic eon. ... The Triassic is a geologic period that extends from about 245 to 202 million years ago (mya). ...

By the end of the Mesozoic Era, the Appalachian Mountains had been eroded to an almost flat plain. It was not until the region was uplifted during the Cenozoic Era that the distinctive topography of the present formed. Uplift rejuvenated the streams, which rapidly responded by cutting downward into the ancient bedrock. Some streams flowed along weak layers that define the folds and faults created many millions of years earlier. Other streams downcut so rapidly that they cut right across the resistant folded rocks of the mountain core, carving canyons across rock layers and geologic structures. The Mesozoic is one of three geologic eras of Phanerozoic eon. ... The Cenozoic or Cainozoic era (sometimes Caenozoic Era) is the most recent of the four classic geological eras. ...

Middle Section of the Appalachians

The middle section of the Appalachians, rather arbitrarily limited by the Hudson and the James rivers contains the best representation of the three longitudinal belts that comprise the whole mountain system. Here, the mountain making compression of the Palaeozoic strata has produced a marvellous series of rock folds with gently undulating axes, trending northeast and southwest through a belt 70 or 80 miles wide. This peculiar configuration of three ridges may be understood as follows:

The pattern of the folded strata on the low lying Cretaceous peneplain must have resembled the pattern of the curved grain of wood on a planed board. When the peneplain was uplifted the weaker strata were worn down almost to a lowland of a second generation, while the resistant sandstones, of which there are three chief members, retained a great part of their new-gained altitude in the form of long narrow even-crested ridges with an occasional sharp bending in peculiar zigzags. These strata are well deserving of the name of Endless Mountains given them by the Indians. The post Tertiary uplift resulting in the present altitude of approximately 1000 to 1500 ft (300 to 450 m). in Pennsylvania and of 2500 to 3500 ft. in Virginia, has not significantly altered the forms thus produced. Rather, it has only incited the rivers to entrench themselves 100 feet (30 m) or more beneath the lowlands of tertiary erosion. As a rule, the watercourses today are longitudinal, following the strike of the weaker strata in paths that they appear to have gained by spontaneous adjustment during the long Mesozoic cycle. However, now and again they cross from one longitudinal valley to another by a transverse course, and there they have cut down sharp notches or water gaps in the hard strata that elsewhere stand up in the long even-crested ridges.

Middle Appalachians Courtesy of USGS

The transition from the strongly folded structure of the Allegheny ridges and valleys to the nearly horizontal structure of the Appalachian plateau is promptly made. With this change in structure comes a change in the form. As the horizontal strata of the plateau present equal ease or difficulty of erosion in any direction, the streams and the submature valleys of the plateau therefore ramify in every direction, thus presenting a pattern that has been called insequent, because it follows no apparent control. - Further mention of the Appalachian plateau is made in a later section. The Endless Mountains are a chain of mountains in northeastern Pennsylvania. ... State nickname: The Keystone State Other U.S. States Capital Harrisburg Largest city Philadelphia Governor Ed Rendell Official languages None Area 119,283 km² (33rd)  - Land 116,074 km²  - Water 3,208 km² (2. ... State nickname: Old Dominion Other U.S. States Capital Richmond Largest city Virginia Beach Governor Mark R. Warner Official languages English Area 110,862 km² (35th)  - Land 102,642 km²  - Water 8,220 km² (7. ... from http://tapestry. ... ...

The crystalline belt of the middle Appalachians, approximately 60 to 80 miles wide, is today of moderate height because the Tertiary upwarping there was more moderate. The height is greatest along the inner or northwestern border of the belt. Here a sub-mountainous topography has been produced by normal dissection, chiefly in the Tertiary cycle. Its valleys are narrow because the rocks are resistant. The relief is strong enough to make occupation difficult. The slopes are forested. The uplands are cleared and well occupied farms and villages, but many of the valleys are wooded glens. As the altitude decreases southeastward, the crystalline belt dips under the coastal plain, near a line marked by the Delaware river from Trenton to Philadelphia, and from there south-southwestward through Maryland and Virginia past the cities of Baltimore, Washington and Richmond. Location in New Jersey Founded  -Incorporated c. ... Independence Hall Philadelphia (sometimes referred to as Philly or the City of Brotherly Love) is the fifth most populous city in the United States and the most populous city in the state of Pennsylvania, occupying all of Philadelphia County. ... State nickname: Old Line State; Free State Other U.S. States Capital Annapolis Largest city Baltimore Governor Robert L. Ehrlich Official languages English Area 32,160 km² (42nd)  - Land 25,338 km²  - Water 6,968 km² (21%) Population (2000)  - Population 5,296,486 (19th)  - Density 165 /km² (5th) Admission into... State nickname: Old Dominion Other U.S. States Capital Richmond Largest city Virginia Beach Governor Mark R. Warner Official languages English Area 110,862 km² (35th)  - Land 102,642 km²  - Water 8,220 km² (7. ... Nickname: Charm City Location in Maryland Founded  -Incorporated 30 July 1729  1797 County Independent city Mayor Martin OMalley (Dem) Area  - Total  - Water 349. ... Aerial photo (looking NW) of the Washington Monument and the White House in Washington, D.C. Washington, D.C., officially the District of Columbia (also known as D.C.; Washington; the Nations Capital; the District; and, historically, the Federal City) is the capital city and administrative district of the... Downtown Richmond as seen from the James River Motto: Sic Itur Ad Astra (Such is the way to the Stars) Nickname: River City Location in Virginia Founded  -Incorporated 1607   County Independent city Mayor Douglas Wilder Area  - Total  - Water 162. ...

The Pennsylvania portion of the crystalline belt is narrow, because of encroachment upon it by the inward overlap of the coastal plain. It is low not only because of the small Tertiary uplift, but more importantly its even discontinous because of the inclusion of belts of weak non-crystalline rock. Here the rolling uplands are worn down to lowland belts, the longest of which reaches from the southern corner of New York, across New Jersey, Pennsylvania and Maryland, into central Virginia. State nickname: The Keystone State Other U.S. States Capital Harrisburg Largest city Philadelphia Governor Ed Rendell Official languages None Area 119,283 km² (33rd)  - Land 116,074 km²  - Water 3,208 km² (2. ... State nickname: The Garden State Other U.S. States Capital Trenton Largest city Newark Governor Richard Codey (acting) Official languages None defined Area 22,608 km² (47th)  - Land 19,231 km²  - Water 3,378 km² (14. ...

The middle section of the Appalachians is further distinguished from the northeastern and southwestern sections by its drainage. Its chief rivers rise in the plateau belt and flow across the ridges and valleys of the stratified belt and through the uplands of the crystalline belt to the sea. The rivers which best exemplify this are the Delaware, Susquehanna and Potomac. The Hudson, the northeastern boundary of the middle section, is peculiar in having headwaters in the Adirondacks as well as in the Catskills (northern part of the plateau). The James, forming the southwestern boundary of the section, rises in the inner valleys of the stratified belt, instead of in the plateau. The generally transverse course of these rivers has given rise to the suggestion that they are of antecedent origin. But there are many objections to this oversimplified, Gordian explanation. The southeast course of the middle section rivers is the result of many changes from the initial drainage. The Mesozoic and Tertiary upwarpings were probably very influential in determining the present general courses. The Delaware River at New Hope, Pennsylvania The Delaware River is a river on the Atlantic coast of the United States. ... The Susquehanna River is a river in the northeastern United States, approximately 410 mi (715 km) long. ... Upper part of the Potomac River The Potomac River flows into Chesapeake Bay, located along the mid-Atlantic coast of the United States (USA). ... Catskill State Park as seen from Overlook Mountian The Catskill Mountains are an extension of the Appalachian Mountains into New York State. ...

For the most part the rivers follow open valleys along belts of weak strata but will frequently pass through sharp cut notches in the narrow ridges of the stratified belt. The Delaware Water Gap is one of the deepest of these notches, and in the harder rocks of the crystalline belt they have eroded steep-walled gorges. The finest is that of the Hudson, because of the greater height and breadth of the crystalline highlands there than at points where the other rivers cross it. The rivers are shallow and more or less broken by rapids in the notches. Rapids also occur near the outer border of the crystalline belt, as if the rivers there had been lately incited to downward erosion by an uplift of the region, and had not yet had time to regrade their courses. This is well shown in the falls of the Potomac a few miles above Washington, in the rapids of the lower Susquehanna and in the falls of the Schuylkill. The Hudson possesses a deep and naturally navigable tide-water channel all through its gorge in the highlands, a feature which, in connection with the Mohawk Valley, has been absolutely determinative of the metropolitan rank reached by New York City at the mouth of the Hudson. The Delaware Water Gap is a geologic formation on the border of New Jersey and Pennsylvania, where the Delaware River traverses a large ridge of the Appalachian Mountains. ... The Schuylkill River, pronounced skookle (SAMPA: /sku:k@5/), is an approximately 130 mile (209 km) long river whose watershed of around 2000 square miles (5,000 km²) lies entirely within the state of Pennsylvania. ...

Northeastern Section of the Appalachians

Northeast Appalachians Courtesy of USGS

The community of characteristics that is suggested by the association of six northeastern states under the name New England is in large measure warranted. All of these states lie within the broadened crystalline belt of the northeastern Appalachians which is approximately 150 miles wide. The uplands which prevail through the center of this area at altitudes of about 1,000 ft. rise to 1,500 or 2,000 ft. in the northwest. Thereafter, these uplands descend to the lowlands of the stratified belt, the St Lawrence-Champlain-Hudson valleys, and at the same time the rising uplands are diversified with monadnocks of increasing number and height and by mature valleys cut to greater and greater depths. Thus, the interior of New England is moderately mountainous. When the central uplands are followed southeast or south to the coast, their altitude and their relief over the valleys gradually decrease. Finally near the coast, the surface gradually passes under the sea. The lower coastal parts, from their accessibility and their smaller relief, are more densely populated. The higher and more rugged interior is still largely forested and thinly settled with there are large tracts of unbroken forest in northern Maine, hardly 150 miles from the coast. In spite of these contrasts, no physiographic line can be drawn between the higher and more rugged interior and the lower coastal border, one merges into the other. New England is a unit, though a diversified unit. from http://tapestry. ... This article is about the region in the United States of America. ... State nickname: The Pine Tree State Other U.S. States Capital Augusta Largest city Portland Governor John Baldacci Official languages None Area 86,542 km² (39th)  - Land 80,005 km²  - Water 11,724 km² (13. ...

The Appalachian trends northeast-southwest that are so prominent in the stratified belt of the middle Appalachians and are fairly well marked in the crystalline belt of New Jersey and Pennsylvania, are prevailingly absent in New England. However, they may be seen in a few areas on the western border:

• in the Hoosac Range along the boundary of Massachusetts and New York.
• in the linear series of the Green Mountain summits (Mt Mansfield. 4364 ft., Killington Peak, 4241 ft.) and their (west) piedmont ridges farther north in Vermont.
• in the ridges of northern Maine.

These are all representative of the various Appalachian structures, as are: The Hoosac Range is a Western Massachusetts mountain range which is part of the Appalachian Mountains and an extension of the Vermont Green Mountains. ... State nickname: Bay State Other U.S. States Capital Boston Largest city Boston Governor Mitt Romney Official languages English Area 27,360 km² (44th)  - Land 20,317 km²  - Water 7,043 km² (25. ... The Green Mountains are a mountain range in the U.S. state of Vermont. ... Mount Mansfield Mount Mansfield is the highest mountain in the U.S. State of Vermont. ...

• certain open valleys such as the Berkshire (limestone) Valley in western Massachusetts and the correspondin Rutland (limestone and marble) Valley in western Vermont.
• the long Connecticut Valley from northern New Hampshire across Massachusetts to the sea at the southern border of Connecticut. The populous southern third of this valley is broadly eroded along a belt of red Triassic sandstones with trap ridges.

However in general, the dissection of the New England upland is as irregular as is the distribution of the surmounting monadnocks. One such is Mount Monadnock in southwestern New Hampshire, a fine example of an isolated residual mass rising from an upland some 1500 ft. in altitude and reaching a summit height of 3186 ft. A still larger example is seen in Mt. Katahdin (5200 ft.) in north-central Maine. Mt. Katahdin is the largest of several similar isolated mountains that are scattered over the interior uplands seemingly randomly. The White Mountains of northern New Hampshire may be thought of as a complex group of monadnocks, all of subdued forms. All that is except for a few cliffs at the head of cirque-like valleys. Mt Washington is the highest of these reaching 6293 ft. Thirteen other summits reach over 5000 ft. The absence of range-like continuity is emphasized here by the occurrence of several low passes or notches leading directly through the group. The best-known of these is Crawford's Notch (1900 ft.). The Triassic is a geologic period that extends from about 245 to 202 million years ago (mya). ... Mount Monadnock, or Grand Monadnock, is a 3,165 foot (965 m) peak in southwestern New Hampshire that has drawn attention for years by its relative isolation from other mountains. ... Mount Katahdin is the highest mountain in Maine. ... This article is about the White Mountains of New Hampshire. ... Mount Washington (formerly Agiocochook) is, at 6,288 ft. ...

In consequence of the general southeastward slope of the highlands and uplands of New England, the divide between the Atlantic rivers and those which flow northward and westward into the lowland of the stratified belt in Canada and New York is generally close to the boundary of these two physiographic districts. The chief rivers all flow south or south-east. These are:

• the Connecticut
• the Merrimack
• the Kennebec
• the Penobscot and
• the St John (in the province of New Brunswick.)

The drainage of New England is unlike that of the middle and southwestern Appalachians in the occurrence of numerous lakes and falls. These irregular features are few south of the limits of Pleistocene glaciation. Further south, the rivers had time in the latest cycle of erosion, to establish a continuous flow, and as a rule, to wear down their courses to a smoothly graded slope. In New England in preglacial times, the rivers were undoubtably also able to establish drainage. Partly due to the irregular scouring of the rock floor, but even more because of the very irregular deposition of unstratified and stratified drift¹ in the valleys, the drainage is now in great disorder. The Connecticut River as seen from the French King Bridge in western Massachusetts The Connecticut River is the largest river in New England, flowing south from the Connecticut Lakes in northern New Hampshire, along the border between New Hampshire and Vermont, through Western Massachusetts and central Connecticut into Long Island... The Merrimack River, formed by the confluence of the Pemigewasset River (left) and Winnipesaukee River (right) is shown on a map of the northeastern United States The Merrimack River (sometimes spelled Merrimac River, an earlier name that is sometimes, although unofficially, used today) is a 110-mile-long (177-kilometer... The Kennebec River is a river, 150 mi (240 km) long, in the state of Maine in the northeastern United States. ... The Penobscot River is a river, 350 mi (563 km) long, in the U.S. state of Maine. ... The St. ... Motto: Spem reduxit (Hope was restored) Other Canadian provinces and territories Capital Fredericton Largest city Saint John Lieutenant Governor Herménégilde Chiasson Premier Bernard Lord (PC) Area 72,908 km² (8th)  - Land 71,450 km²  - Water 1,458 km² (2. ... The Pleistocene Epoch is part of the geologic timescale, usually dated as 1. ...

Many lakes of moderate size and irregular outline have been formed where drift deposits formed barriers across former river courses. The lake outlets are more or less displaced from former river paths. Smaller lakes were formed by the deposition of washed drift around the longest-lasting ice remnants. When the ice finally melted away, the hollows that it left came to be occupied by ponds and lakes. In Maine, lakes of both classes are numerous with the largest being Moosehead Lake, a lake about 35 miles long and with a very irregular shore line. Map of Moosehead Lake. ...

Understanding coastal features requires knowing how the descent of the land surface beneath the sea and from the work of the sea. Thus, the coastal features are always described in connection with their bordering districts. The maturely dissected and recently glaciated uplands of New England are now somewhat depressed with respect to sea level, so that the sea enters the valleys, forming bays and estuaries, while the interfiuve uplands and hills stand forth in headlands and islands. Narragansett Bay, with the associated headlands and islands on the south coast, is one of the best examples. Where drift deposits border the sea, the shore line has been cut back or built forward in beaches of submature expression, often enclosing extensive tidal marshes. However, the bulk of the shore line is rocky and so the change from the initial pattern due to submergence is as yet small. Hence the coast as a whole is irregular, with numerous embayments, peninsulas and islands. In Maine, this irregularity reaches a climax. Narragansett Bay, shown in pink Narragansett Bay is a fjord on the north side of Rhode Island Sound, forming an expansive natural harbor as well as a small archipelago. ...

Southwest Section of Appalachians

As in the northeast, so in the southwest, the crystalline belt widens and gains in height. In New England this belt is an indivisible unit, but the southern crystalline belt must be subdivided into a higher mountain belt on the northwest and a lower piedmont belt on the Appalachian southeast, 100 m. wide, from southern Virginia to South Carolina. This subdivision is already necessary in Maryland, where the mountain belt is represented by the Blue Ridge. At the place where the Potomac cuts across it, it is more of a narrow upland belt than a ridge proper. The piedmont belt, relieved by occasional monadnocks, stretches from the eastern base of the Blue Ridge to the coastal plain, into which it merges. Farther south, the mountain belt widens and attains its greatest development, a true highland district, in North Carolina, where it includes several strong mountain groups. Here Mt Mitchell rises to 6711 ft., the highest of the Appalachians, and about thirty other summits exceed 6000 ft., while the valleys are usually at altitudes of about 2000 ft. Although the relief is strong, the mountain forms are rounded rather than rugged. Few of the summits deserve or receive the name of peaks. Some are called domes, from their broadly rounded tons. Others are known as balds, because the widespread forest cover is replaced over their heads by a grassy cap.

The height and massiveness of the mountains decrease to the southwest, where the piedmont belt sweeps westward around them in western Georgia and eastern Alabama. Some of the residual mountains hereabouts are reduced to a mere skeleton or framework by the retrogressive penetration of widening valleys between wasting spurs. Certain districts within the mountains, apparently consisting of less resistant crystalline rocks, have been reduced to basin-like peneplains in the same amount of time that served only to grade the slopes and subdue the summits of the neighboring mountains of more resistant rocks. The best example of this kind is the Asheville peneplain in North Carolina, measuring about 40 by 20 miles across. In consequence of later elevation, its general surface, now standing at an altitude of 2500 ft is maturely dissected by the French Broad river and its many branches in valleys 300 ft. deep. The basin floor is no longer a plain, but a hilly district in the midst of the mountains.

The rivers of the mountain belt, normally dividing and subdividing in apparently subsequent fashion between the hills and spurs, generally follow open valleys. There are few waterfalls. The streams being as a rule fairly well graded, though their current is rapid and their channels are set with coarse waste. The valley floors always join at accordant levels, as is the habit among normally subdued mountains. Thus, they contrast with glaciated mountains such as the Alps and the Canadian Rockies. In those, the laterals open as hanging valleys in the side slope of the main valleys. It is a peculiar feature of the drainage in North Carolina that the headwaters lie to the east of the highest mountains and that the chief rivers flow northwestward through the mountains to the broad valley lowland of the stratified belt and then through the plateau, as the members of the Mississippi system. It is probable that these rivers follow in a general way courses of much more ancient origin than those of the Atlantic rivers in the middle Appalachians.

The piedmont belt may be described as a maturely dissected peneplain over much of its extent. Indeed, It is one of the best examples of kind. Its uplands are of fairly accordant altitude, which gradually decreases from 500 to 1000 ft. near the mountain belt to half that height along the coastal plain border. Here and there, the uplands are surmounted by residual monadnocks in the form of low domes and knobs. These increase in height and number towards the mountain belt and decrease towards the coastal plain. Stone Mountain, near Atlanta, Georgia, a dome of granite surmounting the schists of the uplands, is a striking example of this. The chief rivers flow southeastward in rather irregular courses through valleys from 200 to 500 ft. deep. The small branches ramify indefinitely in typical insequent arrangement. The streams are nearly everywhere well graded with rapids being rare and lakes unknown.

The boundary between the mountains and the piedmont belt is called the Blue Ridge all along its length. Although the name Blue Ridge is fairly appropriate in northern Virginia, it is not deserved in the Carolinas, where the ridge is only an escarpment descending abruptly 1000 or 1500 ft. from the valleys of the mountain belt to the rolling uplands of the piedmont belt. This form is unusual. It is not defined by rock structure, but appears to result from the retrogressive erosion of the shorter Atlantic rivers, whereby the highlands, drained by much longer rivers, are undercut. The piedmont belt merges southeastward into the coastal plain, the altitudes of the piedmont uplands and of the coastal plain hills being about the same along their line of junction. Many of the rivers, elsewhere well graded, have rapids as they pass from the harder rocks of the piedmont to the semi-consolidated strata of the coastal plain.

Appalachian Great Valley

Extending from the Hudson River valley to Alabama, the Great Valley is one feature of the Appalachians that has greater continuity than any other. It is determined structurally by a belt of topographically weak limestones and shales (or slates) just inland from the crystalline uplands. Hence regardless of the direction of the rivers draining the belt, the valley has been worn down by Tertiary erosion to a continuous lowland from the Gulf of St Lawrence to central Alabama. The lowland is uninterrupted by any transverse ridge throughout its distance of 1,500 miles, though longittidinal ridges of moderate height occasionally diversify its surface. In the middle section, the Great Valley is somewhat open on the east, by reason of the small height and broad interruptions of the narrow crystalline belt. On the west, it is limited by the complex series of Alleghany ridges and valleys. In the northeast section, the valley is strongly enclosed on the east by the New England uplands, and on the west by the Adirondacks and Catskills (see below). In the southwest section, the valley broadens from the North Carolina highlands on the southeast almost to the Cumberland plateau on the northwest due to the weaken, though still present, ridge-making formations. The Cumberland Plateau includes much of eastern Kentucky and western West Virginia in the United States. ...

Coastal Plain

A striking contrast between New England and the rest of the Appalachians is found in the descent of the New England uplands to an immediate frontage on the sea. South of New York harbor, the remainder of the Appalachians are set back from the sea by the interposition of a coastal plain. The plain consists of marine (with some estuarine and fluviatile²) stratified deposits, more or less indurated, which were laid down when the land stood lower and the sea had its shore line farther inland than today. An uplift, increasing to the south, revealed part of the shallow sea bottom in the widening coastal plain, from its narrow beginning at New York harbor to its greatest breadth of 110 or 120 miles in Georgia. There, it turns westward and is continued in the Gulf coastal plain, described farther on. The coastal plain, however, is the result, not of a single recent uplift, but of movements dating back to Tertiary time and continued with many oscillations to the present. Nor is its surface smooth and unbroken, for erosion began on the inner part of the plain long before the outer border was revealed. Indeed, the original interior border of the plain has been well stripped from its inland overlap. The higher standing inner part of the plain is now maturely dissected with a relief of 200 to 500 ft. by rivers extending seaward from the older land anti by their inntimerable branches, which are often of insequent arrangement. The seaward border being the latest uplifted, is prevailingly low and smooth with a hardly perceptible seaward slope of a few feet per mile. The shallow sea deepens very gradually for many miles off shore.

South Carolina and Georgia furnish the broadest and most typical section of this important physiographic province. Here, the more sandy and hilly interior parts are largely occupied by pine forests which furnish much hard or yellow pine lumber, tar and turpentine. Farther seaward, where the relief is less and the soils are richer, the surface is cleared and cotton is an important crop.

A section of the coastal plain, from North Carolina to southern New Jersey, resembles the plain farther south in general form and quality of soils, but besides being narrower, it is further characterized by several embayments or arms of the sea, caused by a slight depression of the land after mature valleys had been eroded in the plain. The coastal lowland between the sea arms is so flat that, although distinctly above sea level, vegetation hinders drainage and extensive swamps occur. Dismal Swamp, on the border of North Carolina and Virginia, is the largest example.

The small triangular section of the coastal plain in New Jersey north of Delaware Bay deserves separate treatment because of the development there of a pectiliar topographic feature, which throws light on the occurrence of the islands off the New England coast, described in the next paragraph. The feature referred to results from the occurrence here of a weak basal formation of clay overlaid by more resistant sandy strata. The clay belt has been stripped for a score or more of miles from its original inland overlap, and worn down in a longitudinal inner lowland, while the sandy belt retains a significant altitude of 200 or 300 ft. overlooking the inner lowland in a well-defined slope dissected by many inland-flowing streams, and descending from its broad crest very gently seaward, thus giving rise to what has been called a belted coastal plain in which the relief is arranged longitudinally and the upland member, with its very unsymmetrical slopes, has sometimes been called a cuesta also known as an escarpment. This is a form of relief frequently occurring elsewhere, as in the Niagara escarpment of the Great Lakes district of the northern United States and in the Cotswold and Chiltern hills of England, typical examples of the escarpment class. The Delaware river, unlike its southern analogs, which pursue a relatively direct course to the sea, turns southwestward along the inner lowland for some 50 miles. The Great Lakes from space The Great Lakes are a group of five large lakes on or near the United States-Canadian border. ...

There is good reason for believing that at least along the southern border of New England a narrow coastal plain was for a time added to the continental border. As in the New Jersey section, this plain was stripped from a significant breadth of inland overlap and worn down so as to form an inner lowland enclosed by a longitudinal upland or escarpment. After this stage was reached, a submergence of the kind which has produced the many embayments of the New England coast drowned the outer part of the plain and the inner lowland. This left only the higher parts of the escarpment as islands. Long Island, Block Island (part of Rhode Island), Martha's Vineyard and Nantucket (parts of Massachusetts) were probably similarly formed. Heavy terminal moraines and outwashed fluviatile plains have been laid on the escarpment remnants, increasing their height as much as 100 ft. and burying their seaward slope with gravel and sand. Moreover, the sea has worked on the original shore line reducing the size of the more exposed islands farther east, and even consuming some islands which are now represented by the Nantucket shoals. Image of Long Island taken by NASA. Long Island, New York, is an island off the North American coast, some 118 miles (190 km) long, and from 12 to 20 miles (32 km) wide, extending from New York Harbor into the North Atlantic Ocean. ... State nickname: The Ocean State, Little Rhody Other U.S. States Capital Providence Largest city Providence Governor Donald Carcieri Official languages None Area 4,005 km² (50th)  - Land 2,709 km²  - Water 1,296 km² (32. ... Marthas Vineyard is roughly triangular in shape, and is approximately 30 kilometers in length. ... Nantucket is an island south of Cape Cod, Massachusetts, formed of glacial moraine. ... State nickname: Bay State Other U.S. States Capital Boston Largest city Boston Governor Mitt Romney Official languages English Area 27,360 km² (44th)  - Land 20,317 km²  - Water 7,043 km² (25. ...

Appalachian plateau

The Catskill Mountains, Adirondacks, Alleghany plateau and the Cumberland plateau are part of the Appalachian plateau. The same Paiaeozoic formations that are folded in the belt of the Alleghany ridges lie nearly horizontal in the plateau district just to its northwest. The exposed strata are in large part resistant sandstones. While they have suffered active dissection by streams during the later cycles of erosion, the hilltops have retained a considerable altitude. In fact, that district is known as a plateau. It might be better described as a dissected plateau since its uplands are not contiguous, rather nearly everywhere the uplands are interrupted by ramifying insequent valleys. In fact, local usage rarely refers to this as the Appalachian plateau since it is not perceived to be one plateau. Its north-eastern part in eastern New York is known as the Catskill Mountains. Here, it reaches truly mountainous heights in great dome-like masses of full-bodied form, with two summits rising a little over 4000 ft. At the eastern border of this part of the plateau is a single strong escarpment descending to the Hudson valley. There are two escarpments on the northern borders towards the Mohawk Valley. Above this is the Adirondacks. The plateau extends southwest into Pennsylvania and Virginia where it is called the Alleghany plateau. In northern Pennsylvania, the lateral pressure of the Palaeozoic moutain-making forces extended its effects through a belt about fifty miles wider than in the folded belt of the Hudson Valley. This caused the compressing the heavy stratified series into great rock waves while in New York, this same stratified series, forming the Catskills, lies horizontal. Altitudes of 1,200 feet prevail in Pennsylvania and increase in Virginia. In the Kentucky and Tennessee portion, where the highest section is called the Cumberland plateau, the altitude falls to about 1,000 feet. The altitude drops further in Alabama where the plateau, like the mountain belt, disappears under the Gulf coastal plain.

Throughout this distance of 1,000 miles, the southwestern border of the plateau is an abrupt escarpment. It is eroded at places where the folded structure of the mountain belt reveals a series of weaker strata. In the northwest, the plateau loses height and relief more gradually until it reaches the praire plains in central Ohio, southern Indiana and Illinois, about 150 miles inland from the escarpment. Two qualifications must be added. In certain parts of the plateau, there are narrow anticlinal uplifts which are an outlying effect of the mountain-making compression. A ridge will rise if the exposed strata are resistant to erosion such as the Chestnut ridge of western Pennsylvania or a valley will be excavated if the exposed strata are more easily eroded such as the Sequatchie Valley which is a long narrow trough cutting off a strip of the plateau from the larger body found in Tennessee. In Kentucky and Tennessee, there is a double alternation of sandstone and limestone in the strata. As the plateau's skyline bevels across these formations, there are west-facing escarpments made ragged by mature dissection as one passess from the topographically strong sandstone to the topographically weak limestone. State nickname: The Buckeye State Other U.S. States Capital Columbus Largest city Columbus Governor Bob Taft Official languages None Area 116,096 km² (34th)  - Land 106,154 km²  - Water 10,044 km² (8. ... State nickname: The Hoosier State Other U.S. States Capital Indianapolis Largest city Indianapolis Governor Mitch Daniels Official languages English Area 94,321 km² (38th)  - Land 92,897 km²  - Water 1,424 km² (1. ... State nickname: Land of Lincoln, The Prairie State Other U.S. States Capital Springfield Largest city Chicago Governor Rod Blagojevich Official languages English Area 149,998 km² (25th)  - Land 143,968 km²  - Water 6,030 km² (4. ...

In the northeast (New York and Pennsylvania), the higher parts of the plateau are drained by the Delaware and Susquehanna rivers directly to the Atlantic. Farther west and southwest, the plateau is drained to the Ohio river and its branches. The submature or mature dissection of the plateau by its branching insequent streams results in giving it an excess of sloping surface, usually too steep for farming, and hence left for tree growth.

The Adirondack Mountains

This rugged district of northern New York may be treated as an outlier in the United States of the Laurentian highlands of Canada that is separated by the St Lawrence Valley. It is part of the Canadian Shield along with the Superior Upland that extends into the U.S. It is of greater altitude (Mt Marcy 5344 ft.) and of much greater relief than the Superior Upland. Its heights decrease gradually to the north, west and south, where it is unconformably overlapped by Palaeozoic strata like those of Minnesota and Wisconsin. On the east, its structure and form is more broken where the disturbances of the Appalachian system have developed ridges and valleys of linear trends. Elsewhere, these ridges and valleys are smaller or barely seen. Canadian Shield The Canadian Shield is a large craton in eastern and central Canada and adjacent portions of the United States, composed of bare rock dating to the Precambrian Era (between 4. ... State nickname: North Star State Other U.S. States Capital Saint Paul Largest city Minneapolis Governor Tim Pawlenty Official languages None Area 225,365 km² (12th)  - Land 206,375 km²  - Water 18,990 km² (8. ... One of the periods of glaciation was also termed the Wisconsin glaciation. ...

¹drift - rock material transported and left deposited.

²Fluviatile - Latin meaning river.

See also

• Acadian orogeny
• Appalachian orogeny
• Taconic orogeny

The Acadian orogeny is a middle Paleozoic deformation, especially in the northern Appalachians, between Alabama and Newfoundland. ... The Appalachian orogeny is a geological event that formed the Appalachian Mountains. ... Illustration of the Taconic orogeny The Taconic orogeny was a great mountain building period that perhaps had the greatest overall effect on the geologic structure of basement rocks within the New York Bight region. ...

External links

• USGS web page about Appalachian Highlands province (public domain source)
• http://tapestry.usgs.gov
• http://pubs.usgs.gov/dds/dds11/

This article incorporates text from the public domain 1911 Encyclopædia Britannica. The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ... The Eleventh Edition of the Encyclopædia Britannica (1911) in many ways represents the sum of knowledge at the beginning of the 20th century. ...