Atlantic Seaboard Fall Line
The Atlantic Seaboard Fall Line, or Fall Zone, is a 900-mile (1,400 km) escarpment where the Piedmont and Atlantic coastal plain meet in the eastern United States.[1] Much of the Atlantic Seaboard fall line passes through areas where no evidence of 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 sediments. Examples of the Fall Zone include the Potomac River's Great 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 head of navigation on rivers due to rapids and waterfalls, such as the Great 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. Some of the cities along the Piedmont—Coastal Plain fall line include, from north to south:
- Paterson, New Jersey on the Passaic River
- Trenton, New Jersey on the Delaware River.[1]
- Philadelphia, Pennsylvania on the Schuylkill River.[2]
- Wilmington, Delaware on Brandywine Creek.[2]
- Newark, Delaware on the Christina River.[citation needed]
- Stanton, Delaware on the White Clay Creek.
- Perryville, Maryland and Havre de Grace, Maryland on the Susquehanna River.
- Baltimore, Maryland, on the Patapsco River.[2]
- Laurel, Maryland on the Patuxent River.[citation needed]
- Washington, D.C. on the Potomac River.[3]
- Occoquan, Virginia on the Occoquan River.[citation needed]
- Fredericksburg, Virginia on the Rappahannock River.[3]
- Richmond, Virginia on the James River.[4]
- Petersburg, Virginia on the Appomattox River.[citation needed]
- Roanoke Rapids, North Carolina on the Roanoke River.[citation needed]
- Smithfield, North Carolina on the Neuse River.[citation needed]
- Fayetteville, North Carolina on the Cape Fear River.[citation needed]
- Cheraw, South Carolina on the Pee Dee River.[citation needed]
- Camden, South Carolina on the Wateree River.[citation needed]
- Columbia, South Carolina on the Congaree River.[4]
- Augusta, Georgia on the Savannah River.[citation needed]
- Columbus, Georgia on the Chattahoochee River.[1]
 |
| State | Point (crossing) | Elevation & coordinates | Fall zone: drop/width (slope) |
Geomorphology Piedmont—Coastal plain |
|---|---|---|---|---|
| New Jersey | New Brunswick (Raritan River) | 460 ft (140 m)40°29′18″N 74°26′52″W / 40.48833°N 74.44778°W | ||
| Trenton (Delaware River) | 40°13′18″N 74°45′22″W / 40.22167°N 74.75611°W | 8 ft | ||
| Pennsylvania | Philadelphia (Schuylkill River by I-76) | |||
| Delaware | Wilmington (Brandywine Creek) | |||
| Maryland | Conowingo Dam (Susquehanna) | |||
| Ellicott City[5] (Patapsco) | 39°16.044′N 76°47.573′W / 39.267400°N 76.792883°W[1] | crystalline rock—unconsolidate marine sediments [2] | ||
| Great Falls (Potomac River) | 38°59′51″N 77°15′9″W / 38.99750°N 77.25250°W | 76 ft/<1 mi (>1.4%) | ||
| Virginia | Fredericksburg (Rappahannock) | 39°16.044′N 76°47.573′W / 39.267400°N 76.792883°W[3] | [west of Interstate 95 bridge][6] | |
| Emporia (Meherrin River)[7] |
References
- ^ a b c Freitag, Bob (2009). Floodplain Management: A New Approach for a New Era. Island Press. p. 77. ISBN 978-1-59726-635-2. Retrieved 17 November 2010.
{{cite book}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ a b c Shamsi, Nayyar (2006). Encyclopaedia of Political Geography. Anmol Publications. pp. 92–93. ISBN 978-81-261-2406-0. Retrieved 17 November 2010.
- ^ a b Deane, Winegar (2002). Highroad Guide to Chesapeake Bay. John F. Blair. p. 5. ISBN 978-0-89587-279-1. Retrieved 17 November 2010.
- ^ a b Roberts, David C. (2001). Roger Tory Peterson (ed.). A Field Guide to Geology: Eastern North America. Houghton Mifflin Harcourt. p. 242. ISBN 978-0-618-16438-7. Retrieved 17 November 2010.
{{cite book}}: Unknown parameter|coauthor=ignored (|author=suggested) (help) - ^ "History/Culture". PatapscoHeritageGreenway.org. Retrieved 2010-09-07.
George Ellicott House: A block away is the 1789 George Ellicott House at 24 Frederick Road., which has been saved, moved out of the flood plain, and restored. The Ellicott family settled here along the fall line of the Patapsco River in 1772 and built an innovative, water-powered flour mill
- ^ "Fall Line". VirginiaPlaces.org. Retrieved 2010-08-13.
- ^ "River and "Fall Line" Cities". VirginiaPlaces.org. Retrieved 2010-08-13.