Cretaceous. At the beginning of the Paleogene geologic period a second wave of
tectonic movements took place causing a further shift. The third wave of
movements during the Paleogene and Neogene resulted in a more complex tectonic
structure. At the same time erosion resulted in stripping of the outer mantle
rocks and further modeling of terrain. Peaks were built from weather resistant
Jurassic rocks, mainly limestone. Valleys and passes were created from softer
and more susceptible to weathering rocks of Cretaceous and Paleogene periods.
Caves are few and rather small. By contrast, rivers and streams are often
deeply indented in the rock, creating approximately 15 ravines and gorges. The
most famous gorges of the Pieniny mountains are the Dunajec River Gorge in
Pieniny National Park and the Homole Ravine (Polish: Wąwóz Homole). Hills along
the northern border of Pieniny are of volcanic origin
