Browse: Cumberland Valley geology

Tuscarora Sandstone, Waggoner's Gap, Cumberland County PA
The hard, resistant Tuscarora Sandstone forms the ridge of North Mountain (Photo: PA Audubon)
Tuscarora Sandstone, Waggoner's Gap, Cumberland County PA
The hard, resistant Tuscarora Sandstone forms the ridge of North Mountain (Photo: Sean Cornell)

Tuscarora Sandstone
The Tuscarora Sandstone in detail.

Tuscarora Sandstone as a building stone, Cumberland County PA
The hard, resistant Tuscarora Sandstone has been used historically as a building stone (Photo: Sean Cornell)
Tuscarora Sandstone as a building stone, Shippensburg PA
Several older homes on Orange Street in Shippensburg are constructed with Tuscarora Sandstone.
Tuscarora Sandstone as a building stone, Shippensburg PA
Detail of house construction with Tuscarora Sandstone.
Martinsburg Shale, Cumberland County, PA
The Martinsburg Shale is steeply dipping here near Middle Spring Creek. Note the sedimentary layering.
Martinsburg Shale, Cumberland County, PA
A second view of the Martinsburg Shale at the same location near Middle Spring Creek.

Conococheague Creek flowing on the Martinsburg Shale near Hagerstown, MD
The regular pattern of these stream meanders is due to structural weaknesses in the shale layers in which the stream cuts its path.

 

Conodoguinet Creek flowing on the Martinsburg Shale near Camp Hill, PA
The regular pattern of these stream meanders is due to structural weaknesses in the shale layers in which the stream cuts its path.
Conodoguinet Creek flowing on the Martinsburg Shale near Newburg, PA
A ground-level view of the creek flowing on the underlying shale.
Stonehenge Formation, Shippensburg, PA
This exposure of the local limestone - named after the stone monument in England - shows enlarged fractures (bedding planes) dipping at a steep angle into the ground.
Stonehenge Formation, Shippensburg, PA
These exposures of the local limestone in this pasture indicate thin soils over bedrock near or at the ground surface.
Limestone, Shippensburg, PA
This example of the local limestone indicates the dissolved conduits common in the local bedrock geology. These voids are produced by dissolution of the limestone under acid conditions.
Sinkhole, Shippensburg, PA
The voids shown in the previous photo can grow into large subterrainean caverns. If large cavities develop close to the ground surface, sinkhole collapse is possible.
Closed Depression near Cleversburg (Cumberland County), PA
Many of these depressions - which sometimes form small ponds - are produced by sinkholes.
Closed Depression near Mainsville (Franklin County), PA
Many of these depressions - which sometimes form small ponds - are produced by sinkholes. (Photo: Tom Feeney)
Entrance to the Cleversburg Sink, Cumberland County, PA
This surface opening leads to an extensive cave system that continues under I-81. (Photo: Tom Feeney)
"The Passages" in Cleversburg Sink, Cumberland County, PA
Underground view of the cave system. (Photo: Tom Feeney)
Big Spring near Newville (Cumberland County), PA
Several large springs like this illustrate the substantial flow of groundwater through voids dissolved in the Cumberland Valley limestones.
  Big Spring Creek near Newville (Cumberland County), PA
The spring in the previous photo generates the full flow of Big Spring Creek, a substantial local stream.