The mineralogical properties of the clay minerals separated from Koyama sand-dune soil were investigated by means of X-ray diffraction analysis, differential thermal analysis and micrographs. The specimens were collected from the four stratigraphically conspicuous outcrops K-1, K-8, K-17 and K-23 as shown in Fig. 1. By these investigations it was recognized that the pumice bed of Daisen Loam (so-called "Kurayoshi Pumice") is consisted mainly with feldspar and allophane. Other stratums of these outcrops are mainly consisted with quartz. The loams of brownish yelllow colour such as K-1.1, K-1.5, K-17.2, K-17.5, K-23.2 and K-23.5, (Figs.2-5) contain gibbsite. The loams K-1.5, K-8.2, K-17.4 and K-23.5 seems to contain halloysite hydrated
