 The mountains within the county are part of the Endless Mountains.The stratigraphic record of sedimentary rocks within the county spans from the Devonian Lock Haven Formation (exposed only in Lick Creek valley) to the coal-bearing Pennsylvanian Allegheny Formation.Generally, the Catskill Formation underlies most of the lowlands, and sandstones of the Huntley Mountain, Burgoon, Mauch Chunk, or Pottsville Formations cap the mountains.