縄文時代のアクセサリーの一つに貝のブレスレット（貝輪）がある．その主要素材であるベンケイガイは， 漂着物としての「打ち上げ貝」が利用されていた．筆者は各地の考古資料を分析するとともに，東日本各地 に所在するベンケイガイの打ち上げ貝集積地の分布調査と，採集した標本の分析をおこなうことで，「縄文人の打ち上げ貝利用」を明らかにした．そしてこの過程で，房総半島南部に所在する千葉県鴨川市浜荻海岸を発見し定期的に調査するようになった．この海岸は，おそらく東日本では最も多量にかつ良好な状態でベンケイガイが打ち上がる地点で，その様相は他所と比較して特異である．この近隣の海域が，ベンケイガイにとって極めて良好な生息地であるとともに，地理的・地形的要因から良好な漂着物集積地だからである．浜荻海岸における定期的調査の目的は，ベンケイガイの打ち上げ情報を，生物学的・漂着物学的・考古学的研究に資するためであるが，一方では，採集した打ち上げ貝類を体験学習用教材に利用するためでもある．本論では，千葉県鴨川市浜荻海岸における過去数年間分のベンケイガイの打ち上げ貝類データを提示するとともに，筆者の所属する市原市教育委員会でおこなっている漂着物を利用した体験学習としての「貝輪づくり」を紹介する．

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In August 1998, massive amounts of marine litter washed up along a stretch of the western coast line of Japans Kyushu region（Satsuma Peninsula in Kagoshima Prefecture）. Soon thereafter, marine litter monitoring began at Fukiagehama Beach on the same coast, and has been conducted monthly for the past 15 years. Since 2009, the monitoring program has provided warning alerts for massive marine litter drift, with the severity of the alerts based on the composition of the source regions and density of the indicator items. In July 2013, very large amounts of marine litter accumulated once again on the same coast. The density of the drift had increased by more than 30-fold compared with last month. The warning alerts for massive marine litter drift were given in this coast line in July 29, 2013 because the density of indicator items was greater than the warning value. The character was that a massive drift from a foreign source was spotted. Disposable lighter was used as an indicator item to identify the source regions as the probable sources of the marine litter. Specifically, the major out flow area was Meizhou City in Guangdong, China. The massive drift was thought to be a result of typhoon Soulik, which caused excessive flooding and destruction in the source regions. In addition to the disposable lighters from China and Taiwan, both blue and orange spindle-shaped plastic floats were used as indicator items from China and Taiwan; the accumulation of these items was estimated to have increased at rates of more than 96-fold, 108-fold, and 52 fold, respectively compared with last month, and some disposable syringes were also found ashore in the surveyed area. However, there are few domestic items. The massive marine drift alert was in place for 5 months until November 2013.

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Drift seeds of Entada species（Leguminosae）in Japan have been recorded as E.phaseoroides from many years ago. Based on the recent taxonomic study of the Genus Entada and many drift records on Entada seeds by the member of Japan Driftological Society, we confirmed that the seeds of four Entada species; E.parvifolia, E.phaseoloides, E.rheedii, E.tonkinensis were drifted in Japan. The drift seed morphology of these four species and their drift distribution were described.

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Molluscs drifted on the coast of Yoron-jima in Amami Islands are studied. Drifted shells are collected from fifteen sites at ebb tide in late June, 2013. The Yoron molluscan fauna is composed of 102 species of shelled molluscs, 38 bivalves and 64 gastropods. The fauna is also dominated by rocky-shore species such as Barbatia fusca, Chama japonica, Strombus luhuanus, Cypraea caputserpentis, Conus flavidus etc. The fauna contains many coral reef elements such as Tridacna crocea, T.maxima, Cypraea annulus, C.moneta and C.mappa. From the specific composition, the fauna is assigned to tropical marine climate.

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Flow and sources of marine litter washed upon the coast of Japan were estimated using the disposable lighter because it has the outflow information of country or location. The outflow country can be classified by a body shape and punched codes on the tank bottom, and the outflow location can be distinguished by a shop address or telephone number printed on the tank surface. From Aug. 2003 to Mar. 2014, total 63, 140 lighters were collected on the total 1,434 beaches（1,384 in Japan, 36 in Taiwan, 9 in Korea, 4 in Russia and 1 in China）. Flow of lighters elicited by the relation ship the outflow location with the collected site was as follows: The lighters flowed out of the Chinese coast from Hong Kong to Shanghai and the west coast of Taiwan mainly wash upon the remote islands area from Yonaguni Island （Okinawa prefecture） to Amami Islands （Kagoshima prefecture） while drifting north ward in the East China Sea, and they inflow to Japan Sea through the Tsushima Strait. A little number of lighters flowed out of western Korea drift southward, however Korean lighters mostly inflow to Japan Sea. The lighters flowing into Japan Sea directly and through the strait drift northward and then outflow to the Pacific Ocean through the Tsugaru Strait. They drift southward along the Tohoku Pacific coast and reach to the area off Ibaraki prefecture. The lighters drifted northward along the west coast of Hokkaido reach to the area off Shiretoko Peninsula in Okhotsk Sea through the Soya Strait. On the pacific coasts from the southern Kyushu to Tokai area, the lighters flowed out of the around inland area mainly wash up. These flows illustrated by the movement of lighters are basically consistent with the ocean currents around Japan reported in previous oceanographic studies.

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2010年７月，北海道様似町平宇海岸において，生痕化石を含む打ち上げ礫を採集した．この礫は，海岸 を構成する新第三系上杵臼層に由来するものである．礫に含まれていた化石を検討した結果，木材に穿孔した 生痕化石Teredolites longissimusであることが判明した．本種は上杵臼層からは初めての産出であり，本層上 部に海進期堆積相があることが示唆された．

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