In the western and southern parts of the Izu Peninsula, the ejecta of ancient submarine volcanoes is widely distributed. After a long period of undersea volcanoes, the whole of Izu rose and emerged on land, and subsequent erosion gave it its current appearance, allowing us to see firsthand the beautiful internal structures that would have been buried underground. Among the submarine volcanic ejecta, volcanic ash and pumice that fell on the seafloor were transformed into stone over a long period of time, retaining the stripes and other patterns that were formed on the seabed. The stone made in this way was useful as a soft, easy-to-process, and fire-resistant stone (Izu stone), and was produced and shipped in various parts of Izu until the beginning of the Showa era. Muroiwa-do is a quarry that was in operation from the Edo period to Showa 29, and is one of the few places where you can visit it while retaining the state of that time.