Houtong Coal Mine Cave Introduction
The potholes of the Keelung River are a world-class geographical landscape, typically occurring in the upstream regions of rivers. The formation of potholes is due to the intense swirling currents carrying sand and gravel that erode the riverbed. Over time, as the water continues to rotate, circular holes known as potholes are created. Between the Hō-tōng Station and the Sandiao Ridge Station along the Pingxi Railway in Ruifang District, the riverbed of the Keelung River cuts into the hard Nuan Nuan sandstone layer, resulting in many smooth depressions on the rock surface, which are referred to as potholes in geomorphology, forming the pothole landscape of the Keelung River. Ruifang's Hō-tōng is the easiest place to reach for viewing potholes. From the Wengzitang Bridge under the visitor center of the Hō-tōng Coal Mine Museum Park, walking upstream along the steps for about 1,700 meters takes approximately 30 minutes to see the Hō-tōng potholes, known locally as "the dimples of the stones." Alternatively, after exiting the Hō-tōng Train Station, one can walk along Hō-tōng Road upstream along the Keelung River to also view the pothole scenery.
