At the coastal region of the Seto Inland Sea in Yamaguchi Prefecture, west Japan, many remains of the ancient times have been excavated and exposed under the railway construction of the Sanyo Shin-Kansen (the super express line) of Japan National Railways. The present authors have studied the magnetic properties of baked earth come from these ancient remains newly excavated.And they have endeavoured to estimate the absolute ages of some of these remains (archaeomagnetic chronology). The sampling technique performed in this study is also briefly described. In general, igneous rocks and also baked earths have feeble magnetic moment (natural remanent magnetization