Editing Fall line

{{Short description|Meeting point of uplands and coastal plain}}
{{About|the concept in geomorphology|fall line as a gradient|Fall line (topography)|other uses|Fall line (disambiguation)}}
A '''fall line''' (or '''fall zone''') is the area where an upland region and a [[coastal plain]] meet and is noticeable especially the place rivers cross it, with resulting [[rapids]] or [[waterfall]]s. The uplands are relatively hard [[Basement (geology)|crystalline basement rock]], and the [[coastal plain]] is softer [[sedimentary rock]].<ref name=schneider>{{cite book |last= Schneider |first= Craig W. |author2=Richard B. Searles |title= Seaweeds of the southeastern United States: Cape Hatteras to Cape Canaveral |year= 1991 |publisher= Duke University Press |isbn= 978-0-8223-1101-0 |pages= 5–7 |url= https://books.google.com/books?id=gWA5kv_0g3cC&pg=PA5 |access-date= 17 November 2010}}</ref> A fall line often will recede upstream as a river cuts out the uphill dense material, forming "c"-shaped waterfalls and exposing bedrock [[shoals]]. Due to these features, riverboats typically cannot travel any further inland without [[portage|portaging]], unless [[Lock (water navigation)|locks]] are built. The rapid change of elevation of the water and resulting energy release make the fall line a good location for [[water mill]]s, [[grist mill]]s, and [[sawmill]]s. Seeking a [[head of navigation]] with a ready supply of water power, people have long made settlements where rivers cross a fall line.

==Geography==
[[File:Bulletin 426 Fig 2 Fall Line.jpg|thumb|right|300px|Diagram showing the Fall Line. [[USGS]] figure.]]
The slope of rivers crossing fall zones affected settlement patterns. For example, the fall line represents the inland limit of navigation of many rivers. Numerous cities along a fall line grew as a result of demand for transferring people and goods between land-based and water-based transportation at that place.<ref name=UGA>{{cite web |url=http://www.gly.uga.edu/railsback/1122EUSMISR.html |title=The Fall Line and major cities of the Eastern U.S.}}</ref>

{{Globalize|section|USA|2name=the United States|date=November 2016}}

===North American Atlantic Seaboard Fall Line===
{{Main|Atlantic Seaboard Fall Line}}

{{GeoGroupTemplate|align=left}}

The '''Atlantic Seaboard Fall Line''', or '''Fall Zone''', is a {{convert|900|mi|km|adj=on|abbr=off|order=flip}} [[escarpment]] where the [[Piedmont (United States)|Piedmont]] and [[Atlantic Coastal Plain]] meet in the eastern [[United States]].<ref name=freitag>{{cite book |last= Freitag |first= Bob |author2=Susan Bolton|author3=Frank Westerlund|author4=Julie Clark |title= Floodplain Management: A New Approach for a New Era |year= 2009 |publisher= Island Press |isbn= 978-1-59726-635-2 |page= 77 |url= https://books.google.com/books?id=e1lr3gQiO8gC&pg=PA77 |access-date= 17 November 2010}}</ref> Much of the Atlantic Seaboard fall line passes through areas where no evidence of [[Fault (geology)|faulting]] is present.

The fall line marks the geologic 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]] [[sediment]]s. Examples of the Fall Zone include the Potomac River's [[Little Falls (Potomac River)|Little Falls]] and the rapids in [[Richmond, Virginia]], where the [[James River]] falls across a series of rapids down to the tidal estuary of the James River.

Before navigation improvements such as locks, the fall line was often the [[wikt:head of navigation|head of navigation]] of rivers due to rapids and waterfalls, like the [[Little Falls (Potomac River)|Little Falls]] of the [[Potomac River]]. Numerous cities were founded at the intersection of rivers and the fall line. [[U.S. Route 1]] links many of the fall line cities.

In the USA, Mid-Atlantic and Southern fall line cities include:
*[[Paterson, New Jersey]], on the [[Passaic River]]{{Citation needed|date=January 2017}}
*[[Trenton, New Jersey]], on the [[Delaware River]]<ref name="freitag" />
*[[Philadelphia|Philadelphia, Pennsylvania]], on the [[Schuylkill River]]<ref name=shamsi>{{cite book |last= Shamsi |first= Nayyar |title= Encyclopaedia of Political Geography |year= 2006 |publisher= Anmol Publications |isbn= 978-81-261-2406-0 |pages= 92–93 |url= https://books.google.com/books?id=4Z2Kh7ELI0oC&pg=PA92 |access-date= 17 November 2010}}</ref><ref name="Dunkerly">{{cite book|last1=Dunkerly|first1=Robert|last2=Boland|first2=Irene|title=Eutaw Springs|date=2017|publisher=The University of South Carolina Press|location=Columbia|isbn=9781611177589|pages=24}}</ref>
*[[Wilmington, Delaware]], on [[Brandywine Creek (Christina River)|Brandywine Creek]]<ref>{{cite web |url=http://www.dgs.udel.edu/delaware-geology/summary-geologic-history-delaware |title= A Summary of the Geologic History of Delaware |publisher= The Delaware Geological Survey |access-date= 25 January 2017}}</ref>
*[[Baltimore|Baltimore, Maryland]], on the [[Jones Falls]], [[Gunpowder Falls]] and [[Gwynns Falls]]<ref>{{cite web |url= http://www.mgs.md.gov/geology/ |title= Maryland Geology |publisher= Maryland Geological Society |access-date= 25 January 2017}}</ref>
*[[Washington, D.C.]], on the [[Potomac River]]<ref name=vaplaces>{{cite web |url= http://www.virginiaplaces.org/regions/fallshape.html |title= Geology of the Fall Line |publisher= Virginia Places |access-date= 25 January 2017}}</ref><ref name="Dunkerly" />
*[[Fredericksburg, Virginia]], on the [[Rappahannock River]]<ref name=vaplaces />
*[[Hanover, Virginia]], on the [[North Anna River]]{{Citation needed|date=January 2017}}
*[[Richmond, Virginia]], on the [[James River]]<ref name=vaplaces/><ref name="Dunkerly" />
*[[Petersburg, Virginia]], on the [[Appomattox River]]<ref name=vaplaces/>
*[[Weldon, North Carolina]], and [[Roanoke Rapids, North Carolina]], on the [[Roanoke River]]<ref name=ncpedia>{{cite web |url= http://www.ncpedia.org/fall-line |title= Fall Line |publisher= NCpedia |access-date= 25 January 2017}}</ref>
*[[Rocky Mount, North Carolina]], on the [[Tar River]]
*[[Fayetteville, North Carolina]], on the [[Cape Fear River]]<ref name=ncpedia/>
*[[Camden, South Carolina]], on the [[Wateree River]]<ref name="Dunkerly" />
*[[Columbia, South Carolina]], on the [[Congaree River]]<ref name=UGA/><ref name="Dunkerly" />
*[[Augusta, Georgia]], on the [[Savannah River]]<ref name=georgiaency>{{cite web |url= http://www.georgiaencyclopedia.org/nge/Article.jsp?id=h-721 |title= Fall Line |publisher= The New Georgia Encyclopedia |access-date= 17 October 2011}}</ref><ref name="Dunkerly" />
*[[Milledgeville, Georgia]], on the [[Oconee River]]<ref name=georgiaency/>
*[[Macon, Georgia]], on the [[Ocmulgee River]]<ref name=georgiaency/>
*[[Columbus, Georgia]], on the [[Chattahoochee River]]<ref name=freitag/>
*[[Tallassee, Alabama]], on the [[Tallapoosa River]]<ref name=alabamaency>{{cite web |url= http://www.encyclopediaofalabama.org/article/h-1618 |title= Fall Line |publisher= Encyclopedia of Alabama |access-date= 25 January 2017}}</ref>
*[[Wetumpka, Alabama]], on the [[Coosa River]]<ref name=alabamaency/>
*[[Tuscaloosa, Alabama]], on the [[Black Warrior River]]<ref name=alabamaency/>

===Canada===
The [[Laurentian Upland]] forms a long scarp line where it meets the [[Great Lakes–St. Lawrence Lowlands]]. Along this line, numerous rivers have carved falls and canyons (listed east to west):
*[[Saint Anne Falls]] and [[Canyon Sainte-Anne]] ([[Sainte-Anne-du-Nord River|River Sainte-Anne-du-Nord]])
*Chaudron à Gaudreault ([[Rivière aux Chiens (Côte-de-Beaupré)|Rivière aux Chiens]])
*Unnamed falls ([[Rivière du Sault à la Puce]])
*Canyon of the [[Cazeau River|River Cazeau]]
*[[Montmorency Falls]] ([[Montmorency River|River Montmorency]])
*[[Parc of the Kabir Kouba Cliff and Waterfall|Kabir Kouba Fall]] ([[Saint-Charles River (Quebec City)|River Saint-Charles]])
*Chute Ford ([[Sainte-Anne River (Les Chenaux)|River Sainte-Anne]])
*Sainte-Ursule Falls ([[Maskinongé River|River Maskinongé]])
*Chute à Magnan ([[Rivière du Loup (Mauricie)|Rivière du Loup]])
*Chutes Émery and Chute du Moulin Coutu ([[Rivière Bayonne]])
*Les sept chutes ([[L'Assomption River|River de L'Assomption]])
*[[Park of Dorwin Falls|Dorwin Falls]] ([[Ouareau River|River Ouareau]])
*Wilson Falls ([[Rivière du Nord (Laurentides)|Rivière du Nord]])
*Long Sault, now flooded by the [[Carillon hydroelectric generating station]] ([[Ottawa River]])
**The [[Chaudière Falls]] run over the unrelated Eardley Escarpment of the [[Ottawa-Bonnechere Graben]].
The [[Jacques-Cartier River|River Jacques-Cartier]] and [[Saint-Maurice River|River Saint-Maurice]] lack such noticeable features because they cross the scarp through [[U-shaped valley]]s. The falls of the lower Saint-Maurice (as well as those of the River Beauport, in [[Quebec City]]) are due to the [[fluvial terrace]]s of the [[Saint Lawrence river]] rather than the Laurentian Scarp.

==See also==
*[[Geologic map of Georgia (U.S. state)]]
*[[Spring line settlement]]

==References==
{{Reflist}}

==External links==
*{{Cite EB1911|wstitle=Fall-line |short=x}}

{{Portal bar|Geology|Earth sciences}}
{{Authority control}}

{{DEFAULTSORT:Fall Line}}
[[Category:Geomorphology]]