Fossils in the Castle Wall Stones 城壁の石の中にある化石

Official explanation

Fossils are sometimes visible in the hard, gray, ancient limestone (ko-ki sekkai-gan) stone used to construct the walls of Nakijin. The stone is found only in this area and was quarried both onsite and nearby. All limestone began on the seafloor eons ago as calcium-rich coral, shells, and the remains of plankton. In Okinawa it ranges from the softer varieties used in most castle walls to the more ancient and harder type used here at Nakijin. Because its hardness makes it difficult to shape and fit the stones as was done at many other Ryukyuan castles, here they were stacked using a simple method called “nozura-zumi,” which takes advantage of their natural shape. Many fossils such as this ammonite have been found embedded in the wall stones, attesting to their ocean-floor origin.

出典: 地域観光資源の多言語解説文データベース（観光庁） — www.mlit.go.jp/tagengo-db. この英語解説文は観光庁の地域観光資源の多言語解説整備支援事業で作成しました。
Source: Japan Tourism Agency, Multilingual Explanation Database. This English text was produced by the Japan Tourism Agency's multilingual explanation project and is shown unedited. Opening hours and services may have changed since it was written.