The study of soil has been researched not only from the view point of colloidal chemistry, but also from more over the soil forming process which from the dynamic view point through the soil profile, since so-called the theory of climatic soil zone has been advocated by DOKUCHAIEV, SIBIRTSEV, GLINKA, RAMANN and others. And also in Japan, much results on the weathering process have been published, but also there is nothing on it in San'in-district. So therefore the authors carried out the following examination. The samples were taken from Kumagasen (Height 300m), Tottori-ken, Hinogun, Kanagawa-mura, Kawagasaki. A) 3-10cm Contained raw humus, so-called Profile A_0. This profile was not taken in our examination. B) 20-100cm brownish yellow, not contained humus, so-called Profile A. For our convenience' sake this layer was described as Profile I. C The layer under Profile I holded the structure of mother rock, so we could distinguish it from Profile I, but the boundary of the two layers was not obvious. The sample was taken from the place of 200 cm under Profile I. We described this layer as Profile II. (D) Under the microscope, mother rock contained quartz and biotite as main component, less feldspar and graphite as secondary component, and more or less apatite. Therefore we could consider this rock as Graphite biotite schist. The result of total analysis by Jakob's method is shown in Table I and according to HARRASSOWTTZ the weathering co-efficient calculated from the result of total analysis shows that Biotite schist in San'in-district has received the wathering process of Kaoline. HCI soluble portion in Profile I and II is shown in Table III, and the result of SiO_2/Al_2O_3,Base/Al_2O_3 and exchangeable acidity by KCl method are shown as follows. [table] SiO_2/Al_2O_3 in clay portion was 1.65 in Profile I and 1.67 in Profile II. So we could consider that the weathering process in San'in-district was not typical Laterization process, but it might be the process which was taken in high temperature and much moisture reason. By Gedroiz and Bobko's method we determined the absorptive capacity, the amount of H-ion and the exchangeable base, and by Hissink's method the saturation degree was determined as shown in the following tables. [table] The amount of free alumium soluble in 10% Na_2CO_3 was determined by Seki's method, and its amount in Profile I was in between Brown soil and Red soil and the amount in Profile II was almost as Same as in Brown Soil, comparing with the result denoted by STEBUTT. (Table XII) And also according to HARASOWITZ, Biotite-schist in San'in-district has received so-called his "Allitic weathering process." Lang's Ragenfaktor and Meyer's N-S Quatient in San'in-district are calculated as follows. [table] Now we can sum up as follows, (1) This examination is the study on the weathering process of Biotite-schist in San'in-district, Japan. (2) Biotite-Schist in Sani-district may receive so-called Harrassowitz' Allitic weathering process. (3) In the climatic soil type, this soil belongs to the medium soil type, transitional from Brown soil, between Brown soil and Red soil. (4) The value of Lang's Ragenfaktor is not agree with the result of chemical analysis and the observation in the field. (5) Meyer's N-S Quatient in Hamada shows that the Brown soil may be appear in San'in-district, but N-S Quatient in Sakai and Miyadu intimate the other type of soil may be obvious.