近世西三河地域の綿作の地域的特色を,先進地である畿内と比較して検討した.その結果,西三河地域においては,田方綿作・自然堤防地帯の畑方綿作・洪積台地上の畑方綿作・新田砂畑綿作の四つの立地類型がみられた.そのうち,自然堤防地帯の綿作が生産規模の点において,最も中心的地位を占めていたことがわかった.次に,ある上層農の農業経営の分析を通して,西三河地域の綿作の諸側面を明らかにした.上層農の例をもってしても,西三河地域の綿作の生産力は,畿内地域に比べてかなり低いこと,綿の生産量には年々大きな変動があること,水田での綿作では4年に1度田に戻す稲綿輪作が行なわれていたこと,畑方綿作は雑穀との輪作ないし綿の連作として行なわれていたこと,などが明らかになった.西三河地域の綿作は古い歴史を有するにもかかわらず,畿内地域ほどの先進性を示すことがなかった.その最大の原因は,畿内綿作が多様な商品作物生産の一環としての近郊・集約的綿作であったのに対し,西三河綿作が綿単.の商品作物生産を行なう遠郊・粗放的綿作であった点に求められる.

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積雪地域である新潟県長岡市周辺において,積雪および融雪浸透水が,地温・地下水温に及ぼす影響を明らかにするために,熱・水文環境の観測と地下水温の解析を行なった・その結果, (1) 積雪層自体が深層の地下水温に及ぼす影響は小さいが,融雪水の浸透により毛管水帯内の地温が全層的に低下すること,また (2) 融雪浸透水による地下水位の上昇期と相対的な冷温域の下方への急激な拡大の時期が一致し,この原因は浸透水のもたらす熱移流であること,などが明らかになった.また, (3) 融雪浸透水を含む年間を通した浸透水の存在は,恒温層上限深度を低下させることも明らかになった.さらに, (4) 熱移流による年間の負の貯熱変化量は正の値:より大きく,実際の地下水温分布は,熱伝導方程式に基づく理論解より低温方向へずれる.その主な原因は,上層ほど低温な温度環境下での浸透に起因する融雪浸透水であることがわかった.

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The present report concerns the results of abrasion test of gravels in a Los Angeles type tumbling barrel. The purpose of this study is to test the existence of a deficiency zone in the grain size distribution of deposits observed in the field by Yatsu (1954, 1955), Sundborg (1956), Pettijohn (1957), and Moriyama (1978).
A 20-kg gravel sample was taken from riverbed deposits of the Iruma, which forms an alluvial fan in the western part of the Kanto Plain. Sampled gravels were composed of subangular metamorphic sandstone, shale and chert.
The abrasion test was stopped periodically and the sample was sieved for particles coarser than 4 φ in order to determine the size distribution. Products of the particles finer than 4 φ were analyzed by the hydrometer method. Roundness of gravels coarser than -1.25 φ was measured using Krumbein's chart.
The main results are as follows:
A deficiency in particles 0 to 2 φ in diameter appeared clearly, and this “valley” in the size distribution curve became deeper and wider as the abrasion test went on. It seems that particles of 0 to 2 φ and the neighbouring diameters are easily attrited and difficult to produce from progressively rounding gravels. Finally, grain size distribution showed a bimodal curve. The position of the coarse mode around -4 φ hardly shifted during the test. It seems that the coarse gravels were gradually worn down and rounded, producing finer particles of fine sand, silt and clay; they were seldom broken into two particles, rarely producing gravel and coarse sand.

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In mid-temperate latitudes, elongate and small ridges are commonly developed on the shore of many inland lakes which are frozen over in winter. Such minor features are formed by ice action and called “ice rampart”. Sediments in the shallow water region are transported onshore and heaped up on the lacustrine shore by the shoreward movement and landing of ice plates to form ice ramparts.
During the summer survey of 1982, the author noticed the existence of ice ramparts located on the shore of Lake Kussharo in eastern Hokkaido, Japan (Fig. 1). The purpose of this paper is to describe the distribution, shape, size and internal structure of ice ramparts on the shore of this lake and to discuss the cause of lake ice movement.
Two study sites were chosen on the east shore of this lake where a number of ice ramparts were well developed. Using a level, levelling rod and a tape, lacustrine shore topography was surveyed along many traverses in each study site. Observations of the internal structure of ice ramparts were also made. During the period from freeze-up to break-up, observations on the changes in the shore topography of both study sites were made at regular intervals. The distribution of ice ramparts on the whole shore of this lake was investigated.
Examination of the survey results indicated that the ice ramparts were developed on the shore in a single or a few rows and were composed of sand and gravel (Figs. 2 and 3). These ice ramparts were normally formed on the whole shore except the location of steeply inclined slope below the water level (Fig. 4). According to many previous studies on the formation of ice ramparts, there are two main causes for the shoreward movement and landing of ice plates: (1) the thermal expansion and contraction of lake ice due to variations in air temperatures; and (2) wind action upon separated ice plates in the spring thaw. The meteorological data at Teshikaga indicate that during the winter season, large and relatively rapid alternations of air temperature below the freezing point frequently occur in the study area, and the snow cover is ordinarily thin in the study area (Figs. 5 and 6). Such intermediate climatic conditions in the study area are favorable for the thermal expansion and contraction of lake ice. Observations on the shoreward movement and landing of ice plates indicated that the ice ramparts on the shore of this lake were mainly formed by the movement of lake ice, which is caused by the thermal expansion and contraction of the ice as described above (Figs. 7 and 8).

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