The geology of the Appalachians dates back more than 1.1 billion years to the Mesoproterozoic era when two continental cratons collided to form the supercontinent Rodinia, 500 million years prior to the later development of the range during the formation of the supercontinent Pangea. The rocks exposed in today's Appalachian Mountains reveal 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 and neighboring Anti-Atlas mountains near the center. These mountain ranges likely once reached elevations similar to those of the Alps and the Rocky Mountains before they were eroded.
Red Rocks Park is a mountain park in Jefferson County, Colorado, owned and maintained by the city of Denver as part of the Denver Mountain Parks system. The park is known for its very large red sandstone outcrops. Many of these rock formations within the park have names, from the mushroom-shaped Seat of Pluto to the inclined Cave of the Seven Ladders. The most visited rocks, around Red Rocks Amphitheatre, are Creation Rock to the north, Ship Rock to the south, and Stage Rock to the east.
Old Rag Mountain is a 3,284 feet (1,001 m) mountain near Sperryville in Madison County, Virginia. A part of the Blue Ridge Mountains, the peak is located within Shenandoah National Park and is the most popular hiking destination within the park.
Trough Creek State Park is a 554 acres (224 ha) Pennsylvania state park in Cass, Penn and Todd Townships, Huntingdon County, Pennsylvania in the United States. The majority of the park is in Todd Township along Pennsylvania Route 994, east of the unincorporated village of Entriken. Huntingdon is the nearest borough. The park borders Rothrock State Forest and Raystown Lake National Recreation Area. There is a growing population of bald eagles at the lake. Fourteen eagles were spotted in January 2007. This is up from two that were spotted in 1990, the first year that an eagle survey was taken. These three sections of state and federal owned property combine together to provide hunting, hiking and fishing opportunities for the outdoorsman.
Bald Eagle Valley is a low-lying area in Pennsylvania that drains into Bald Eagle Creek between the Allegheny Front and Bald Eagle Mountain, south of the West Branch Susquehanna River, in the Ridge-and-valley Appalachians. The valley is located southwest of West Branch Susquehanna Valley and includes Williamsport, Nittany Valley, and State College in the central portion of Centre County and southern portion of Clinton County.
Bald Eagle Mountain – once known locally as Muncy Mountain – is a stratigraphic ridge in the Ridge-and-Valley Appalachians of central Pennsylvania, United States, running east of the Allegheny Front and northwest of Mount Nittany. It lies along the southeast side of Bald Eagle Creek and south of the West Branch Susquehanna River, and is the westernmost ridge in its section of the Ridge-and-Valley Appalachians. The ridge line separates the West Branch Susquehanna Valley from the Nippenose and White Deer Hole valleys, and Bald Eagle Valley from Nittany Valley.
North Fork Mountain is a quartzite-capped mountain ridge in the Ridge and Valley physiographic province of the Allegheny Mountains, also known as the High Alleghenies or Potomac Highlands, of eastern West Virginia. Kile Knob, at 4,588 feet, is the mountain's highest point, and Panther Knob and Pike Knob are nearly as high.
Brush Mountain is a stratigraphic ridge in the Appalachian Mountains of central Pennsylvania, United States, lying east of the Allegheny Front and west of Tussey Mountain. It runs along the southeast side of the Little Juniata River and forms a horseshoe around Sinking Run, and is the westernmost ridge in its section of the Ridge-and-valley Appalachians. The western ridge line separates the Logan Valley from the Sinking Valley.
Tussey Mountain is a stratigraphic ridge in central Pennsylvania, United States, trending east of the Bald Eagle, Brush, Dunning and Evitts Mountain ridges. Its southern foot just crosses the Mason–Dixon line near Flintstone, Maryland, running north 130 km (80 mi) to the Seven Mountains of central Pennsylvania, near Tusseyville, making it one of the longest named ridges in this section of the Ridge-and-valley Appalachians.
The Geology of Pennsylvania consists of six distinct physiographic provinces, three of which are subdivided into different sections. Each province has its own economic advantages and geologic hazards and plays an important role in shaping everyday life in the state. From the southeast corner to the northwest corner of the state, the include: the Atlantic Plain Province province, the Piedmont Province, the New England Province, the Ridge and Valley Province, the Appalachain Province, and the Central Lowlands Province.
The Silurian Tuscarora Formation — also known as Tuscarora Sandstone or Tuscarora Quartzite — is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia, US.
Bedford County, Pennsylvania is situated along the western border of the Ridge and Valley physiographic province, which is characterized by folded and faulted sedimentary rocks of early to middle Paleozoic age. The northwestern border of the county is approximately at the Allegheny Front, a geological boundary between the Ridge and Valley Province and the Allegheny Plateau.
For other "River Knobs", see River Knobs (disambiguation).
The Ordovician Reedsville Formation is a mapped surficial bedrock unit in Pennsylvania, Maryland, Virginia, West Virginia, and Tennessee, that extends into the subsurface of Ohio. This rock is a slope-former adjacent to the prominent ridge-forming Bald Eagle sandstone unit in the Appalachian Mountains. It is often abbreviated Or on geologic maps.
Stone Mountain is a stratigraphic ridge that is located in central Pennsylvania, United States, trending northwest of the Jacks Mountain ridge and Jacks Mountain Anticline. The ridge line separates Kishacoquillas Valley from the Seven Mountains area. Stone Mountain lies in, and the ridge line forms part of the border between, Mifflin and Huntingdon counties.
West Virginia's geologic history stretches back into the Precambrian, and includes several periods of mountain building and erosion. At times, much of what is now West Virginia was covered by swamps, marshlands, and shallow seas, accounting for the wide variety of sedimentary rocks found in the state, as well as its wealth of coal and natural gas deposits. West Virginia has had no active volcanism for hundreds of millions of years, and does not experience large earthquakes, although smaller tremors are associated with the Rome Trough, which passes through the western part of the state.
The Pennsylvanian Pottsville Formation is a mapped bedrock unit in Pennsylvania, western Maryland, West Virginia, Ohio, and Alabama. It is a major ridge-former in the Ridge-and-Valley Appalachians of the eastern United States. The Pottsville Formation is conspicuous at many sites along the Allegheny Front, the eastern escarpment of the Allegheny or Appalachian Plateau.
Dinosaur Ridge is a segment of the Dakota Hogback in the Morrison Fossil Area National Natural Landmark located in Jefferson County, Colorado, near the town of Morrison and just west of Denver.
Humpback Rocks is a massive greenstone outcropping near the peak of Humpback Mountain in the Blue Ridge Mountains of Augusta County and Nelson County, Virginia, United States, with a summit elevation of 3,080 feet (940 m). The rock formation is so named for the visual effect of a "hump" it creates on the western face of the mountain.
Canoe Mountain is a stratigraphic ridge in central Pennsylvania, United States, running east of the Allegheny Front and west of Tussey Mountain. It forms a continuous ridge with Brush Mountain to the west. To the south, across the water gap formed by the Frankstown Branch Juniata River, the ridgeline continues as Lock Mountain.
