Geology of Bedford County, Pennsylvania
Encyclopedia
Bedford County, Pennsylvania
Bedford County is a county located in the U.S. state of Pennsylvania. As of the 2010 census, the population was 49,762. The county seat is Bedford. It is part of the Altoona, Pennsylvania, Metropolitan Statistical Area.- History :...
, Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
is situated along the western border of the Ridge and Valley
Ridge-and-valley Appalachians
The Ridge-and-Valley Appalachians, also called the Ridge and Valley Province or the Valley and Ridge Appalachians, are a physiographic province of the larger Appalachian division and are also a belt within the Appalachian Mountains extending from southeastern New York through northwestern New...
physiographic province
United States physiographic region
The list of continental United States Physiographic regions identifies the 8 regions, 25 provinces, and 85 sections. The system dates to Nevin Fenneman's paper Physiographic Subdivision of the United States, published in 1917...
, which is characterized by folded
Fold (geology)
The term fold is used in geology when one or a stack of originally flat and planar surfaces, such as sedimentary strata, are bent or curved as a result of permanent deformation. Synsedimentary folds are those due to slumping of sedimentary material before it is lithified. Folds in rocks vary in...
and faulted sedimentary rock
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
s of early to middle Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
age. The northwestern border of the county is approximately at the Allegheny Front
Allegheny Front
The Allegheny Front is the major southeast- or east-facing escarpment in the Allegheny Mountains in southern Pennsylvania, western Maryland, and eastern West Virginia, USA. The Allegheny Front delineates the Ridge-and-Valley Appalachians to its east from the Appalachian Plateau to its west...
, a geological boundary between the Ridge and Valley Province and the Allegheny Plateau
Allegheny Plateau
The Allegheny Plateau is a large dissected plateau area in western and central New York, northern and western Pennsylvania, northern and western West Virginia, and eastern Ohio...
(characterized by relatively flat-lying sedimentary rock
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
s of late Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
age). (PA Geological Survey Map 13)
The stratigraphic record
Stratigraphy
Stratigraphy, a branch of geology, studies rock layers and layering . It is primarily used in the study of sedimentary and layered volcanic rocks....
of sedimentary rock
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
s within the county spans from the Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
Warrior Formation to the Pennsylvanian
Pennsylvanian
The Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods of the Carboniferous Period. It lasted from roughly . As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain...
Conemaugh Group (in the Broad Top
Broad Top
Broad Top is a plateau located in south-central Pennsylvania. It extends into Huntingdon County to the north, Fulton County to the southeast, and Bedford County to the southwest. It is bounded to the west by Saxton Mountain and Terrace Mountain, and to the east by Sideling Hill. In Bedford...
area). No igneous
Igneous rock
Igneous rock is one of the three main rock types, the others being sedimentary and metamorphic rock. Igneous rock is formed through the cooling and solidification of magma or lava...
or metamorphic
Metamorphic rock
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...
rocks of any kind exist within the county.
The primary mountains within the county (From west to east: Wills
Wills Mountain
Wills Mountain is a quartzite-capped ridge in the Ridge and Valley physiographic province of the Appalachian Mountains in Pennsylvania and Maryland, USA, extending from near Bedford, Pennsylvania to near Cumberland, Maryland...
, Evitts
Evitts Mountain
Evitts Mountain is a stratigraphic ridge in the Ridge and Valley region of the Appalachian Mountains, located in Bedford County, Pennsylvania and Allegany County, Maryland-Geography:...
, Dunning, and Tussey
Tussey Mountain
]Tussey Mountain is a stratigraphic ridge in central Pennsylvania, United States, trending east of the Bald Eagle, Brush, Dunning and Evitts Mountain ridges...
mountains) extend from the southern border with Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
to the northeast into Blair County
Blair County, Pennsylvania
-Significant Topographic Features:*Brush Mountain*Logan Valley*Morrison Cove*Tussey Mountain-Demographics:As of the census of 2000, there were 129,144 people, 51,518 households, and 34,877 families residing in the county. The population density was 246 people per square mile . There were 55,061...
, and are held up by the Silurian
Silurian
The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
Tuscarora Formation
Tuscarora Formation
The Silurian Tuscarora Formation — also known as Tuscarora Sandstone or Tuscarora Quartzite — is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia.-Description:...
, made of quartz sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
and conglomerate
Conglomerate (geology)
A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
. Chestnut Ridge
Chestnut Ridge, Bedford County
Chestnut Ridge is an elongate hill trending northeast-southwest in west-central Bedford County, Pennsylvania. It is partially forested with rural homes, farms, and notably apple orchards. Four small towns surround it: Schellsburg, New Paris, Fishertown, and Pleasantville...
is a broad anticline
Anticline
In structural geology, an anticline is a fold that is convex up and has its oldest beds at its core. The term is not to be confused with antiform, which is a purely descriptive term for any fold that is convex up. Therefore if age relationships In structural geology, an anticline is a fold that is...
held up by the Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
Ridgeley Member
Ridgeley sandstone
The Ridgeley sandstone is a sandstone or quartzite of Devonian age found in the Appalachian Mountains of Pennsylvania, Maryland, West Virginia, and Virginia, USA. The Ridgeley is fine-grained, siliceous, calcareous in its lower strata, sometimes fossiliferous, and sometimes locally pebbly or...
of the Old Port Formation, also made of sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
and conglomerate
Conglomerate (geology)
A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
. Broad Top
Broad Top
Broad Top is a plateau located in south-central Pennsylvania. It extends into Huntingdon County to the north, Fulton County to the southeast, and Bedford County to the southwest. It is bounded to the west by Saxton Mountain and Terrace Mountain, and to the east by Sideling Hill. In Bedford...
, located north of Breezewood, is a plateau of relatively flat-lying rocks that are stratigraphically higher, and thus younger (Mississippian and Pennsylvanian
Pennsylvanian
The Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods of the Carboniferous Period. It lasted from roughly . As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain...
), than most of the other rocks within the county (Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
through Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
). Broad Top extends into Huntingdon County
Huntingdon County, Pennsylvania
Huntingdon County is a county located in the U.S. state of Pennsylvania. In 2010, its population was 45,913.Huntingdon County was created on September 20, 1787, from part of Bedford County. Its county seat is Huntingdon.-Geography:According to the U.S...
to the north and Fulton County
Fulton County, Pennsylvania
Fulton County is a county located in the U.S. state of Pennsylvania. As of 2010, the population was 14,845.Fulton County was created on April 19, 1850, from part of Bedford County and named for inventor Robert Fulton.Its county seat is McConnellsburg....
to the east.
The Raystown Branch of the Juniata River
Juniata River
The Juniata River is a tributary of the Susquehanna River, approximately long, in central Pennsylvania in the United States. The river is considered scenic along much of its route, having a broad and shallow course passing through several mountain ridges and steeply-lined water gaps...
is the main drainage in the northern two-thirds of the county. The river flows to the east through the mountains within the county through several water gap
Water gap
A water gap is an opening or notch which flowing water has carved through a mountain range. Water gaps often offer a practical route for road and rail transport to cross mountain ridges.- Geology :...
s caused by a group of faults trending east-west through the central part of the county. The river then turns north and flows into Raystown Lake
Raystown Lake
Raystown Lake is a reservoir in Huntingdon County, Pennsylvania. The largest lake that is entirely within Pennsylvania, it was created by the United States Army Corps of Engineers around 1913 by the damming of the Raystown Branch Juniata River which created a shallow lake in the river valley. ...
in Huntingdon County. The southern third of the county is drained by several tributaries of the Potomac River
Potomac River
The Potomac River flows into the Chesapeake Bay, located along the mid-Atlantic coast of the United States. The river is approximately long, with a drainage area of about 14,700 square miles...
. Both the Potomac and Juniata rivers are part of the Chesapeake Bay
Chesapeake Bay
The Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's drainage basin covers in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West...
Watershed.
All of Bedford County lies far to the south of the glacial boundary
Glacial boundary
A glacial boundary is a line on a map representing the farthest advance of a glacier that has retreated. It generally refers to the extent of continental, rather than alpine, glaciers....
, and thus it was never glaciated (PA Geological Survey Map 59). However, during the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
epoch, or "Ice Age," periglacial
Periglacial
Periglacial is an adjective originally referring to places in the edges of glacial areas, but it has later been widely used in geomorphology to describe any place where geomorphic processes related to freezing of water occur...
(meaning "around glacier" or simply "cold") processes dominated. Most of the county was most likely a tundra
Tundra
In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...
at that time. The many boulder fields obvious as rocky and often treeless areas on mountainsides within the county formed as a result of seasonal freeze-thaw cycles during the Pleistocene.
Several limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
quarries
Quarry
A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...
exist in Bedford County, most of which are owned and operated by New Enterprise Stone & Lime Company. Quarry locations include Ashcom, New Paris (inactive), Kilcoin (closed), and Sproul (inactive).
Two coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
fields exist within Bedford County. One is the Broad Top
Broad Top
Broad Top is a plateau located in south-central Pennsylvania. It extends into Huntingdon County to the north, Fulton County to the southeast, and Bedford County to the southwest. It is bounded to the west by Saxton Mountain and Terrace Mountain, and to the east by Sideling Hill. In Bedford...
Field in the northeastern corner of the county, and the other is the Georges Creek Field along the southwestern border (PA Geological Survey Map 11). Both fields contain bituminous coal. There are abandoned mines in both areas and acid mine drainage
Acid mine drainage
Acid mine drainage , or acid rock drainage , refers to the outflow of acidic water from metal mines or coal mines. However, other areas where the earth has been disturbed may also contribute acid rock drainage to the environment...
is an environmental problem in the Broad Top area, where several fishless streams exist as a result of the discharge from the abandoned mines.
Natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
fields and storage areas exist in southeastern Bedford County, primarily within folded Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
rocks south of Breezewood
Breezewood, Pennsylvania
Breezewood is an unincorporated town in Bedford County in south-central Pennsylvania.Along a traditional pathway for Native Americans, European settlers, and British troops during colonial times, in the early 20th century, the small valley that became known as Breezewood was a popular stopping...
. Another deep gas field exists in the vicinity of Blue Knob on the border with Blair County
Blair County, Pennsylvania
-Significant Topographic Features:*Brush Mountain*Logan Valley*Morrison Cove*Tussey Mountain-Demographics:As of the census of 2000, there were 129,144 people, 51,518 households, and 34,877 families residing in the county. The population density was 246 people per square mile . There were 55,061...
to the north. (PA Geological Survey Map 10)
Interesting Features
Interesting geologic features within Bedford County include some of the following:- New Enterprise New Paris quarry, where fossil corals and bryozoans may be found within the DevonianDevonianThe Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
Keyser FormationKeyser FormationThe Late Silurian to Early Devonian Keyser Formation is a mapped limestone bedrock unit in Pennsylvania, Maryland, Virginia, and West Virginia.-Description:...
. - Coral Caverns in Manns ChoiceManns Choice, PennsylvaniaManns Choice is a borough in Bedford County, Pennsylvania, United States. The population was 291 at the 2000 census.-Name:In 1848, Congressman Job Mann pressured to have a post office at an unnamed village in Harrison Township. The Post Office Department approved the new post office, but as the...
. - The roadcut through Warrior Ridge on Rt. 30 (Everett Bypass), where an exposure of SilurianSilurianThe Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
and DevonianDevonianThe Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
rocks from limestoneLimestoneLimestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
to shaleShaleShale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
to conglomerateConglomerate (geology)A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
can be seen. - The roadcut on the north side of the Pennsylvania TurnpikePennsylvania TurnpikeThe Pennsylvania Turnpike is a toll highway system operated by the Pennsylvania Turnpike Commission in the Commonwealth of Pennsylvania, United States. The three sections of the turnpike system total . The main section extends from Ohio to New Jersey and is long...
at the NarrowsThe Narrows (Pennsylvania)The Narrows is a water gap where the Raystown Branch of the Juniata River passes through Evitts Mountain in Bedford County, Pennsylvania. Both U.S. Route 30 and the Pennsylvania Turnpike pass through the gap...
water gapWater gapA water gap is an opening or notch which flowing water has carved through a mountain range. Water gaps often offer a practical route for road and rail transport to cross mountain ridges.- Geology :...
(where the Raystown Branch cuts through Evitts MountainEvitts MountainEvitts Mountain is a stratigraphic ridge in the Ridge and Valley region of the Appalachian Mountains, located in Bedford County, Pennsylvania and Allegany County, Maryland-Geography:...
) exposes a continuous section of the Reedsville FormationReedsville FormationThe 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...
, Bald Eagle FormationBald Eagle FormationThe Ordovician Bald Eagle Formation is a mapped bedrock unit in central Pennsylvania, USA. It is a ridge-forming unit in the Appalachian Mountains.-Description:...
, Juniata FormationJuniata FormationThe Ordovician Juniata Formation is a mapped bedrock unit in Pennsylvania and Maryland. It is a relative slope-former occurring between the two prominent ridge-forming sandstone units: the Tuscarora Formation and the Bald Eagle Formation in the Appalachian Mountains.-Description:The Juniata is...
, and the Tuscarora FormationTuscarora FormationThe Silurian Tuscarora Formation — also known as Tuscarora Sandstone or Tuscarora Quartzite — is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia.-Description:...
. The beds of the Bald Eagle are overturned, folded, and faulted. The Tuscarora and Juniata are also exposed on the south side of the gap along Rt. 30. - Sweet Root Natural Area, within Buchanan State ForestBuchanan State ForestBuchanan State Forest is a Pennsylvania State Forest in Pennsylvania Bureau of Forestry District #2. The main office is located in McConnellsburg in Fulton County, Pennsylvania, in the United States...
and located near ChaneysvilleChaneysville, PennsylvaniaChaneysville is an unincorporated community in Southampton Township, southern Bedford County, Pennsylvania, United States.-External links:*...
, where periglacialPeriglacialPeriglacial is an adjective originally referring to places in the edges of glacial areas, but it has later been widely used in geomorphology to describe any place where geomorphic processes related to freezing of water occur...
processes have created a bouldery landscape by eroding the Tuscarora FormationTuscarora FormationThe Silurian Tuscarora Formation — also known as Tuscarora Sandstone or Tuscarora Quartzite — is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia.-Description:...
of Tussey MountainTussey Mountain]Tussey Mountain is a stratigraphic ridge in central Pennsylvania, United States, trending east of the Bald Eagle, Brush, Dunning and Evitts Mountain ridges...
. - Blue KnobBlue Knob (Pennsylvania)Blue Knob is a Pennsylvania summit with a broad dome that is the most northern of the 3,000 footers in the range of Allegheny Mountains. The mountain covers of Blue Knob State Park and contains approximately 18 miles of hiking trails and numerous overlooks. A ski area is located on the...
, a notable ski resort and recreational area, is also the state's second highest point at 3146 feet/959 m (after Mount DavisMount Davis (Pennsylvania)Mount Davis is the highest point in Pennsylvania. Located in the 5,685 acre Forbes State Forest in Elk Lick Township, Somerset County, it rises to 3,213 ft...
in Somerset CountySomerset County, PennsylvaniaSomerset County is a county located in the state of Pennsylvania. As of 2010, the population was 77,742. Somerset County was created on April 17, 1795, from part of Bedford County and named for Somerset, United Kingdom. Its county seat is Somerset. It is part of the Johnstown, Pennsylvania,...
to the west). - A transpressionTranspressionTranspression is a geological term used to describe a region of the Earth's crust that experiences strike-slip shear and a component of shortening, resulting in oblique shear. Transpression typically occurs at a regional scale, such as plate boundaries that have an oblique convergence. More...
structure is located on the northern border of the county (shared with Blair CountyBlair County, Pennsylvania-Significant Topographic Features:*Brush Mountain*Logan Valley*Morrison Cove*Tussey Mountain-Demographics:As of the census of 2000, there were 129,144 people, 51,518 households, and 34,877 families residing in the county. The population density was 246 people per square mile . There were 55,061...
), about three miles east of the town of Woodbury. This structure is an up-thrust block of CambrianCambrianThe Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
and OrdovicianOrdovicianThe Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...
rocks bounded on all sides by north-trending faults. The southern tip of the structure is approximately at Pulpit Hill. - An outcrop on the north side of Rt. 30 about three miles west of the village of Juniata Crossing shows an excellent example of a thrust faultThrust faultA thrust fault is a type of fault, or break in the Earth's crust across which there has been relative movement, in which rocks of lower stratigraphic position are pushed up and over higher strata. They are often recognized because they place older rocks above younger...
within the DevonianDevonianThe Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
Catskill Formation. - The Raystown Branch of the Juniata RiverJuniata RiverThe Juniata River is a tributary of the Susquehanna River, approximately long, in central Pennsylvania in the United States. The river is considered scenic along much of its route, having a broad and shallow course passing through several mountain ridges and steeply-lined water gaps...
between BreezewoodBreezewood, PennsylvaniaBreezewood is an unincorporated town in Bedford County in south-central Pennsylvania.Along a traditional pathway for Native Americans, European settlers, and British troops during colonial times, in the early 20th century, the small valley that became known as Breezewood was a popular stopping...
and Raystown LakeRaystown LakeRaystown Lake is a reservoir in Huntingdon County, Pennsylvania. The largest lake that is entirely within Pennsylvania, it was created by the United States Army Corps of Engineers around 1913 by the damming of the Raystown Branch Juniata River which created a shallow lake in the river valley. ...
to the north is an example of a river with incised (or entrenched) meanderMeanderA meander in general is a bend in a sinuous watercourse. A meander is formed when the moving water in a stream erodes the outer banks and widens its valley. A stream of any volume may assume a meandering course, alternately eroding sediments from the outside of a bend and depositing them on the...
s.