本研究では,常磐海岸南部に分布する6枚のテフラを他地域のテフラと対比し,この成果に基づき,同地域の段丘とその下に埋没している谷の発達史を海面変化との関係から考察した.水戸市東方で海成層 (見和層上部層)に覆われる河成礫層 (見和層中部層)は,その発達規模と見和層上部層に介在するテフラ (KIP-7)からみて最終間氷期最盛期 (約12-13万年前)に先立つ安定した低海面期に形成されたと判断される同層の基底地形の形成以降最終間氷期最盛期にかけて海面は少なくとも70m以上の上昇をみた.久慈川以南に発達する那珂台地面,東茨城台地面は,テフラ (KIP-7と K-Tz)との層位関係からみて最終間氷期最盛期から約8万年前にかけて形成された一続きの海成面であるが,一部に河成の部分もみられる.これに対し久慈川以北では,それぞれ最終問氷期最盛期と約8万年前に2つの海成面が形成された.久慈川を境に海成面の発達が異なるのは,両地域での海底地形の相違を反映して波傘作用が異なるため・海食崖の発達に差異が生じたためとみられる.

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わが国の著名な避暑地・別荘地である軽井沢を事例として取り上げ,場所イメージの成立とその変化の過程を具体的に示すことによって,どのように「高級別荘地・避暑地」としての軽井沢のイメージが定着し,より多くの人々の問に浸透していったかを明らかにする.方法として,まず軽井沢を扱った文学作品や新聞・雑誌の記事などをもとに,過去の人々が抱いていた軽井沢のイメージを復元し,それを軽井沢の開発史と重ね合わせながら,軽井沢のイメージ,とくに「高級避暑地・別荘地」としてのイメージが歴史的にどのように形成され,定着していったかを記述した.次にそのイメージの定着の結果として引き起こされた地名の改変とくに「軽井沢」の名を冠した地名の分布の拡大という現象を解釈した.これらの結果は,ある一定の社会集団のレベルで,ある種の場所イメージが定着することを記号関係の形成(場所イメージの記号化)として捉えることにより,よりよく理解することができる.

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The feralization of livestock is one of the themes of geography, but few studies have been done aside from those of T. L. McKnight. The author studied feral pigs, with particularr emphasis on distribution, time of the feralization, background of feralization, and attitudes toward feral pigs, through analysis of reference works in geography and other academic fields and investigation in Australia and the Ogasawara Islands in Japan.
The author examined the distribution of feral pigs in comparison with that of Eurasian wild boars (from which pigs are domesticated). The distinction between feral pigs and Eurasian wild boars is not always clear, however. Domestic pigs roamed and had opportunities to become wild under traditional husbandry practices such as free ranging and mast feeding in Europe and Asia, and they are mostly regarded to have merged with Eurasian wild boars. Further, introduced Eurasian wild boars interbred with feral pigs in the United States, the Republic of South Africa, and parts of South America. Almost everywhere there is evidence of human modification of the indigenous fauna.
Regarding the time of feralization, the author examined data from North and South America, Australia, and some islands where the time was comparatively clear. According to this analysis, pigs were introduced to some islands in the Pacific Ocean by Melanesians and Polynesians, and feralization occurred even though their distribution was limited. From the 15th century to the 19th century, explorers, colonists, sealers, and whalers introduced or released pigs on many oceanic islands and new continents. In this period, pig feralization occurred frequently, and the main feral pig's areas were established. Deliberate release by landholders and hunters continues in some areas even today.
Extensive husbandry, deliberate release, and accidental escape are important factors in feralization. The spread of practices such as free ranging and mast, feeding contributed to pig feralization. Deliberate release by explorers, fishermen, landholders, and hunters is also a major factor. In these cases, we can point out the influence of humans who recognize the value of feral pigs as sources of food or game.
Regarding attitudes toward feral pigs, the author examined data from Australia and the United States. In general, feral livestock including feral pigs were useful to pioneers and early settlers as supplementary animals. But as time passed, feral pigs came to be legally classified as noxious or verminous in Australia because of the damage they caused wheat farmers and raisers of sheep and cattle. In the United States, where such severe damage did not occur, feral pigs are legally classified as game. However, in both countries there are conflicts of interest among farmers, hunters, and landholders who collect hunting fees; all these groups have different attitudes toward feral pigs, which make it difficult to control feral pigs effectively.
In the Ogasawara Islands, feral pigs were recorded as early as Commodore Perry's expedition in 1853. But it is difficult to collect clear evidence of these feral pigs today. In the period in which the islands under occupation by the U. S. Navy after World War II, pigs were brought from Tinian Island by the Navy, and a number of them were released. It is said that pigs were released for food supply and game on Ototo Island and Chichi Island, as a future source of food of fishermen on Muko Island and Nakodo Island. Their descendants are thought to have survived on Ototo Island.

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