In geomorphology, a fall line (at times referred to as a fall zone) marks the area where an upland region (continental bedrock) and a coastal plain (coastal alluvia) meet. Geomorphology (from Greek: γη ge, "earth" μορφή morfé, "form" and λόγος Logos, "knowledge" Bedrock is the native consolidated rock underlying the surface of a terrestrial planet usually the Earth. A coastal plain is an area of flat low-lying land adjacent to a seacoast and separated from the interior by other features Alluvium (from the Latin, alluvius, from alluere, "to wash against" is Soil or Sediments deposited by a river or other running Technically, a fall line is an unconformity. An unconformity is a buried Erosion surface separating two rock masses or strata of different ages indicating that Sediment deposition was not A fall line is typically prominent when crossed by a river, for there will often be rapids or waterfalls. Many times a fall line will recede upstream as the river cuts out the uphill dense material, many times forming “c” shaped waterfalls. Because of these features river boats typically cannot travel any farther inland without portaging unless locks are built. Portage refers to the practice of carrying a Canoe or other Boat over land to avoid an obstacle on the water route (such as Rapids or a Waterfall On the other hand, the rapid change in elevation of the water, and the resulting energy release, makes the fall line a good location for a water mill. Because of the need for a port and a ready supply of water power, settlements often develop where rivers cross a fall line.

The fall line in the United States

Along the eastern coast of the United States, the east-facing escarpment where the Piedmont of the Appalachians descends steeply to the coastal plain forms a fall line over 1500 kilometers long. The United States of America —commonly referred to as the In Geomorphology, an escarpment is a transition zone between different physiogeographic provinces that involves a sharp steep Elevation differential characterized Piedmont is a plateau region located in the eastern United States between the Atlantic Coastal Plain and the main Appalachian Mountains, stretching The Appalachian Mountains ( often called the Appalachians, are a vast system of mountains in eastern North America. The Atlantic Coastal Plain is the flat stretch of land that borders the Atlantic Ocean (including the Gulf of Mexico) The kilometre ( American spelling: kilometer) symbol km is a unit of Length in the Metric system, equal to one thousand This long fall line (also referred to as the Fall Zone) played a major role in settlement patterns along rivers, back into prehistoric times. It is often referred to simply as "the fall line" or "the fall zone". In some places the fall line may be abrupt, while in others it is a zone that may be many miles wide. Geologically the fall line marks the boundary of hard metamorphosed terrain—the product of the Taconic orogeny—and the sandy, relatively flat outwash plain of the upper continental shelf, formed of unconsolidated Cretaceous and Tertiary sediments. 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 The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of The chuprichondira geological time interval covers roughly the time span between the demise of the non- avian Dinosaurs and beginning of the most recent Ice Age, approximately Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of Examples of the Fall Zone include the rapids in Richmond, Virginia, where the James River falls across a series of rapids down to the tidal estuary of the James River. This article is about the city of Richmond the capital of the Commonwealth of Virginia. The James River in the US state of Virginia is a long River, including its Jackson River source

There are a few different theories as to how a Fall Line is formed or why they exist, and one in particular, brought forward by American Physiographer W. J. McGee states that a Fall Line is created through monoclinal faulting/flexing experienced in the region. While this theory is accepted by many geomorphologists much of the fall line along the east coast of the United States passes through areas where no evidence of faulting is present. In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement

In the 19th Century, the fall line often represented the head of navigation on rivers at points like Little Falls or the Great Falls, on the Potomac River. The Great Falls of the Potomac River are located at the Fall line of the Potomac River, 14 miles (22 However, since the advent of flumes for water supply and canals for shipping in the early 20th Century, the most prominent feature of fall line settlement was the establishment of the cities along it. A flume is an open artificial water channel in the form of a gravity chute, that leads Water from a Diversion dam or Weir completely aside As the cities were linked by the early highways, U.S. Route 1 and Interstate 95 came to pass through many of these cities, roughly tracing the fall line. US Route 1 (US 1 is a major north-south US Highway that serves the East Coast of the United States. Interstate 95 ( I-95) is the main Highway on the East Coast of the United States, paralleling the Atlantic Ocean from Maine to

Cities along the Piedmont – Coastal Plain fall line include, from north to south:

• New Brunswick, New Jersey on the Raritan River
• Trenton, New Jersey on the Delaware River
• Philadelphia, Pennsylvania on the Schuylkill River
• Wilmington, Delaware on the Brandywine Creek
• Conowingo, Maryland on the Susquehanna River
• Baltimore, Maryland on the Patapsco River
• Laurel, Maryland on the Patuxent River
• Washington, D.C./Georgetown/Alexandria on the Potomac River (Great Falls National Park)
• Occoquan, Virginia on the Occoquan River
• Fredericksburg, Virginia on the Rappahannock River
• Richmond, Virginia on the James River
• Petersburg, Virginia on the Appomattox River
• Roanoke Rapids, North Carolina on the Roanoke River
• Smithfield, North Carolina on the Neuse River
• Cheraw, South Carolina on the Pee Dee River
• Camden, South Carolina on the Wateree River
• Columbia, South Carolina on the Congaree River
• Augusta, Georgia on the Savannah River
• Milledgeville, Georgia on the Oconee River
• Macon, Georgia on the Ocmulgee River
• Columbus, Georgia on the Chattahoochee River
• Wetumpka, Alabama on the Coosa River
• Tuscaloosa, Alabama on the Black Warrior River

Cities along other fall lines include:

• Lowell, Massachusetts on the Merrimack River
• Hartford, Connecticut on the Connecticut River
• Albany, New York on the Hudson River

See also

• Escarpment
• Fall Line Freeway

References

• USGS: The Fall Line: A Tapestry of Time and Terrain
• Virginia Places website: The Fall Line
• Virginia Places website: Rivers and Fall Line Cities provides a more detailed explanation of why some towns and cities along a Fall line grew and others did not. New Brunswick, also known as "the Healthcare City" or "Hub City" is a city and the County seat of Middlesex County The Raritan River is a major river of central New Jersey in the United States. Trenton is the Capital of the US state of New Jersey and the County seat of Mercer County. The Delaware River is a river on the Atlantic coast of the United States. Philadelphia (ˌfɪləˈdɛlfiə The Schuylkill River, most often ˈskuːkəl ("SKOO-kull" is a river in the U Wilmington is the largest city in the state of Delaware, United States and is located at the confluence of the Christina River and Brandywine Brandywine Creek may refer to several places in the United States mostly streams Streams British Columbia Conowingo is a small community in western Cecil County Maryland, USA. The Susquehanna River (originally "Sasquesahanough" per the 1612 John Smith map is a River located in the northeastern United States. The Patapsco is a River in central Maryland which flows into the Chesapeake Bay in Baltimore Maryland. Laurel is a Maryland, US The Patuxent River is a Tributary of the Chesapeake Bay in the state of Maryland. Washington DC ( formally the District of Columbia and commonly referred to as Washington, the District, or simply D Georgetown is a Neighborhood located in the Northwest quadrant of Washington D Alexandria is an Independent city in the Commonwealth of Virginia. The Potomac River flows into the Chesapeake Bay, located along the mid- Atlantic coast of the United States. Great Falls Park is a small National Park Service (NPS site in Virginia, United States. Occoquan is a town in Fairfax and Prince William counties in the U The Occoquan River flows into the Potomac River at Belmont Bay, and is located in Northern Virginia, along the mid-Atlantic coast of the United Fredericksburg is an Independent city in the Commonwealth of Virginia and is located 50 miles south of Washington D The Rappahannock River is a river in eastern Virginia in the United States, approximately 184 mi (294 km in length This article is about the city of Richmond the capital of the Commonwealth of Virginia. The James River in the US state of Virginia is a long River, including its Jackson River source Petersburg is an Independent city in Virginia, United States located on the Appomattox River. The Appomattox River is a tributary of the James River, approximately 137 miles (220 km in central and eastern Virginia in the United States, named for Roanoke Rapids is a city in Halifax County, North Carolina, United States. The Roanoke River is a river in southern Virginia and northeastern North Carolina in the United States, 410 mi (660 km long Smithfield is a town in Johnston County, North Carolina, United States. The Neuse River is a major permanent stream rising in the piedmont of North Carolina, emptying into the Pamlico Sound below New Bern. Cheraw (officially tʃʌrɔː chuh-raw often also /ʃʌrɔː/ shuh-raw) is a town in Chesterfield County, South Carolina, United States The Pee Dee River, also known as the Great Pee Dee River, is a River in North Carolina and South Carolina. Camden is a city in and the County seat of Kershaw County, South Carolina, United States. The Wateree River, about 75 mi (120 km long is a Tributary of the Santee River in central South Carolina in the United States, which flows Columbia is the state capital and largest city in the US state of South Carolina. The Congaree River is a short but wide river in South Carolina in the United States; It flows for only 47 miles (78 km Augusta Georgia is a city in Richmond County, Georgia, United States. For the Department of Energy facility see Savannah River Site The Savannah River is a major river in the southeastern United States Milledgeville is a town in and the County seat of Baldwin County in the U The Oconee River is a river which has its origin in Hall County Georgia, and terminates 170 Miles (274 km) later where it joins the Ocmulgee River Macon is a city located in central Georgia, USA It is among the largest metropolitan areas in Georgia and the county seat of Bibb County. The Ocmulgee River (ok-MUHL-gee is a tributary of the Altamaha River, approximately 255 mi (410 km long in the U Columbus is a City in Muscogee County, Georgia, United States. The Chattahoochee River runs from the Chattahoochee Spring in the Appalachian Mountains of northeastern Georgia, near the Carolinas to the southwestward Wetumpka is a city in Elmore County, Alabama, United States. At the 2000 census the population was 5726 The Coosa River is one of Alabama's most developed rivers It begins at the confluence of the Oostanaula and Etowah Rivers in Rome Georgia Tuscaloosa is a city in west central Alabama in the southern United States. The Black Warrior River is a tributary of the Tombigbee River, approximately 178 mi (286 km long in west central Alabama Lowell is a city in Middlesex County, Massachusetts, USA. As of the 2000 census the city had a total population of 105167 The Merrimack River (or Merrimac River, an earlier spelling that is sometimes still used is a -long river in the northeastern United States. The Connecticut River is the largest River in New England, flowing south from the Connecticut Lakes in northern New Hampshire, along the border Albany is the Capital of the State of New York and the County seat of Albany County. The Hudson River, called Muh-he-kun-ne-tuk, the Great Mohegan by the Iroquois, or as the Lenape Native Americans called it in Unami In Geomorphology, an escarpment is a transition zone between different physiogeographic provinces that involves a sharp steep Elevation differential characterized The Fall Line Freeway is a highway currently being constructed that will run the width of the state of Georgia from Columbus to Augusta, passing through
• The Geology of Georgia