Senjojiki Rock Terrace
Senjojiki is a raised coastal terrace in Shirahama. Literally, “a thousand tatami mats,” the name refers to the wide, flat surface of layered sandstone and mudstone, giving the effect of an expanse of tatami floor mats.
Senjojiki Rock Terrace was part of the shallow seabed more than 15 million years ago but has risen about five centimeters a century since then. The rocks furthest inland would have been underwater 120,000 years ago, and fossilized sea worm trails and wave ripples can be seen imprinted in the rock. As tectonic plates slowly push these rocks out of the sea, waves erode their surfaces, smoothing them and creating their uneven slopes. The terrace is a rare example of visible layers of yellow sandstone and brown mudstone and is an important site for geological studies.
Next to the terrace is a cave system where long-fingered bats (Miniopterus schreibersi fuliginosus) breed. It is the only breeding spot in the region, inhabited by over 30,000 bats.