A Study on Footprints of Pliocene-Pleistocene Land Mammals.

分别对志贺的康江遗址、岩手的花木遗址、新泻的小寺町遗址和兵库市明石市海岸等哺乳动物足迹地点进行了地层学、年代学和古环境调查。此外，对这些化石足迹的研究还尝试了模式分析。在研究过程中，在大阪通大林市石川河床、长野野尻湖湖底以及日本和印度尼西亚的其他地方，新发现了独特的化石足迹。(1)除野尻湖（Lake Nojiri）外，这些足迹遗址的地层层位大多集中在下更新世层位。即使在日本以外，上新世-更新世足迹的存在也同样在世界范围内具有吸引力，东非Laetoli和美国西德克萨斯遗址也是如此。(2)从沉积学上看，所有这些足迹都具有埋于薄交替粉砂中，并在干湿条件下嵌入粗砂的特征。因此，脚印的形成可能与特定的时代和空间环境有关。(3)通过化石足迹的模式识别，部分地特异性地识别宿主动物成为可能。例如，人类的晚更新世大象古仿齿象（Elephant Paleoloxodon naumanni）的足迹模式可以与早更新世大象Stegod onaurae的足迹模式区分开来。

Investigations of stratigraphy, geochronology and paleoenvironment have been carried out respectively for mammalian footprint localities such as the sites of River Yasu of Shiga, Hanamaki of Iwate, Koshiji-machi of Niigata and sea coast of Akashi City, Hyogo. In addition, pattern analysis has been a ttempted in the study to those fose fossil footprints. In the course of study, distinct fossil footprints have been newly found in Ishikawa river bed at Tondabayashi City of Osaka, lake bottom of Lake Nojiri of Nagano and other localities in Japan and Indonesia.(1) The stratigraphic horizons of those footprint sites are mostly concen-trated in the Lower Pleistocene beds, except for a case of Lake Nojiri. Even outside Japan, the presence of Pliocene-Pleistocene footprint are attractive worldwide likewise Laetoli of East Africa and West Texas sites of U. S. A.(2) Sedimentologically all of those footprints are characteristic of embedding in thin alternation silt-sand with intercalations of coarse sand which were deposited under dry-wet condition. Therefore, the formation of footprint could be connected with a circumstance of peculiar age and space.(3) It becomes to be possible partly to identify host animals specifically from the pattern recognition of fossil footprints. For example, foot-print patterns of Nauman's Elephant Paleoloxodon naumanni of Late Pleisto-cene is able to be discriminated from that of Early Pleistocene elephant Stegod onaurorae.