aeeble

The valley landscape of the Keelung River, aside from waterfalls, between Pingxi Station and Sandiaoling, features numerous rounded potholes on the riverbed, known as "pot-holes" in geological terms. The formation of potholes is due to the uneven structural hardness of the geological rock layers, which, after being eroded by river water carrying fine sand, creates holes, and then the swirling water in the holes further erodes them, forming small, pot-like caves. Potholes typically appear in the concave sections of meandering river bends with many whirlpools and rapid currents, and where the riverbed is composed of exposed hard rock. The most notable and densely distributed potholes can be found below Dahua Station, known as the Dahua Pothole Group. Under the interaction between water flow and rock layers, almost all types of potholes can be seen here, making it a natural geographic classroom.