Abstract
The surveying of ancient paddy fields by plant opal analysis has recently found practical application in archaeological excavation.
This paper discusses problems encountered in the remains of ancient paddy fields of the Yayoi period excavated at the Megumi site in Tottori prefecture and the Tareyanagi site in Aomori prefecture.
1. The distribution of paddy fields surveyed by plant opal analysis agrees with the results of archaeological excavation in both sites.
2. The mean size of ancient paddy fields is 33.7m2 at the Megumi site and 7.8m2 at the Tareyanagi site. This difference seems to have arisen from the circumstances of water supply.
3. The lateral lengths of plant opals originating from rice plants (Oryza sativa) of the Yayoi period have larger mean values than those from the middle ages.
