Susquehanna Lowland Section
Ridge and Valley Province
The Susquehanna Lowland Section consists of low to moderately high, linear ridges and linear valleys, and the Susquehanna River valley. Relatively soft shales, limestone, and siltstones occur in most of the lowlands. The local relief is much less than the Appalachian Mountain section to the west. The Section was formed in the same way; the rocks were compressed toward the northwest by pressure from the southeast. This pressure folded the rocks into the long, linear folds. Erosion of the folded rocks created the ridges and valleys of the Susquehanna Lowland Section. The shales and siltstones are eroded more easily than the sandstones. Thus, as erosion proceeded, the slowly eroded harder rocks like sandstones form ridges while the softer rocks such as shales and siltstones are eroded more rapidly to form the lowlands.
The Susquehanna Lowland Section occurs in east-central Pennsylvania where it occurs in parts of 13 counties including Clinton, Columbia, Dauphin, Juniata, Luzerne, Lycoming, Montour, Northumberland, Perry, Schuylkill, Snyder, Sullivan and Union.
Typical topography can be viewed almost anywhere within the Section. There are excellent views along US Routes 322; along US Route 15 between Harrisburg and Williamsport; along Interstate 80; and along many roads that are in the valleys parallel to the ridges.
Some of the Outstanding Scenic Geological Features include Peters Mountain Overlook, Picture Rocks, Council Cup Scenic Overlook, Juniata River Overlook, Montandon Sand Dunes, The Pinnacle, and near The Pinnacle - Sharp Ridge, Shikellamy Overlook, Warm Springs and Whaleback.