抄録
The article deals with the dark bands in volcanic ash beds which cover the tertiary hills and uplands in southern Kwanto Region. The main conclusions are as follows:
1. Dark bands show no peculiarity in grain sizes and mineral composition-s, but abound in organic carbon and nitrogeon. Dark colors are due to humic materials.
2. Field observations tell they are not the zones of illuviation at present time. So, they are so-called -fossil soils, and are able to be used tephrochro-nologically as secondary key horizons.
3. One to six bands are observed. The upper two are most common, and the lower ones are sometimes shown by cracky or chocolate-colored zones.
4. Soil-types shown by these fossil soils are uncertain. However, according to their thickness and its uniformity, prairie conditions are imagined at those times.
5. These fossil soils have close relation with the stone implements of Ja-panese palaeolithic era which has been closed up after Second World War.
