Flysch is a sedimentary rock formed by the alternate deposition of thin layers of silt and sandstone, found near shorelines that were rapidly experiencing changes in sea level. They are formed underwater along the continental shelf when the area undergoes large structural deformation due to interaction of tectonic plates. As the continental plate gets shoved and heaved, landslides deposit layers of sediments. Due to the different sedimentation speed of grains with different size, a gradation takes place. Bigger particles sink faster and build up the ground layer and are overlain by finer grains. These landslides occur in irregular intervals resulting in the formation of layers upon layers of grains with thickness ranging from a few centimeters to several meters in some cases. At some point, structural deformation caused by colliding tectonic plates tilts the sedimentary beds to near vertical. Over time, the less resistant layers weather out more quickly creating long parallel grooves in the rock.

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