Abstract
The human coxal bone, which was discovered by N. NAORA at seacliff near Akashi in 1931, was pointed out on the primitivity of its form by Dr. K. HASEBE who proposed to name " Nipponantkropus "provided it is verified to have occorred from lower pleistocene deposit there. The bone was discovered at the earth heap which was dislocated down from upper part of the cliff and was not excavated from the original formation. In 1948 the excavation was effected at the ajuscent part of the cliff where the bone had been found, but neither human bone nor any kind of artefacts was discovered anew. The result of geological survey verified that the formation from which the bone was estimated occur belongs to the lower pleistocene. As the bone was destroyed in the war, the author, in aim to estimate the horizon in which the bone had possibly been preserved, examined some pedological properties of the formation and the state of several fossils excavated near the site. The results are as follows: (1) In respect to the pedological properties, the formation is classified into three parts; the strata uuder the sea level, the strata in reductive condition above the the sea level (a-c, fig 1) and the strata in oxidative condition (d-f, ibid.).
(2) In the strata above the sea level, the bone is assumably not to be preserved in good condition for a long time: the earth in the formation all acidic, the exchangeable Ca contents are measured small, the fossil-shells in strata c-d remain only cutin layer and the teeth of an ancient elephant in stratum c consist of several enamel plates with almost all parts of cement and dentine lost.
(3) On the contrary, the formation under the sea level would possibly permit the good preservation of bone; the earth presents alkaline reaction, a large amount of exchangeable Ca and satisfactorily fossilized bones by Limonite, Pyrite, Marcasite etc.
(4) The difference in the pedological properties of strata below and above the sea level is seemingly due to the elevation of the land. A reference was made on the possibility of preservation with the case in which a land elevation lifted a bone fossilized below the sea level above it, but the possibility was also assumed to be negative.
(5) The outcome of the mentioned study could not suggest the horizon above the sea level from which the ptblematical bone had possibly occured. But the primitivity and the age of the bone, however, shall remain unaffected by this conciusion.
