Abstract
Good amount of bony remains, human skeletons, animal bones, teeth and horns of deer including many kinds of artefacts made of them have been found from prehistoric sites in Japan. But they were mostly found in coastal shellmounds and rarely in inland refuse deposits. Two possible cases are regarded as the reason for the latter case ; (1) the absence of bony substances from prehistoric times, (2) the chemical decay of them which once existed at the sites. If the case (1) is true, it concerns with important cultural characteristics of the prehistoric people who lived at the site. The author measured pH, exchangable acidity and exchangable calcium of the soil sampled at Ubayama shellmound in Chiba Pref. and Kitami refuse deposit in Tokyo City, 1% citric acid soluble phosphor content of the soil from the latter site and pH of other two shellmounds and other two refuse deposits. There were plenty findings of bony remains at those shellmounds but none at all at those refuse deposits. The range of pH of these shellmounds are 7.66-8, 47 and that of those refuse deposits are 5, 45-6, 38, exchangable acidity (DAIKUBAAR' S acidity) are 1vs 1-8 and exchangable calcium are over 500 vs 40-200. The phosphor contents of Kitami site were, as reported previously (in this Journal Vol. 61, No. 1), 10-50 times higher in the soil accumulated on the dwelling pits and their closely adjacent parts than the soil outside of them. One of the several burial mounds of later times which locates 300m apart from the mentioned prehistoric site, yielded no skeletal remains at all except for some thin enamel plates of teeth. Besides those experimental data, it is a noteworthy fact that the bony substances which consist of apatite microcrystals, ossein and other organic substances, are chemically resistant against alkaline solution but soluble in acidic solution, and the chemical resistancy of tooth enamel is superior to that of bone. According to those exper imental and theoretical data, the author conclude as follows; (1) The shellmounds should avail good preservation of bony substances because of their alkaline reaction resulting from their plenty accumulation of calciumcarbonate. (2) In the refuse deposits, on the contray, will be neccessary to consider the probability that the bony substances which once existed were decayed by the acidic permiated water and the decompoing action of siol microorganisms. The soil of Japann which shows acidic reaction by ca. 95% of the whole teritory is considered to prevent the preservation of bony substances in it. (3) Both refuse deposit and shellmound seem to have the similar significance in their fomation at least at the sites studied.
