A Study on Footprints of Pliocene-Pleistocene Land Mammals.

对滋贺县安须川、岩手县花卷、新泻县越地町、兵库县明石市海岸等哺乳动物足迹地点分别进行了地层学、年代学和古环境调查。此外，对这些化石足迹的研究也尝试了模式分析。研究过程中,在大阪富田林市石川河床、长野野尻湖湖底以及日本和印度尼西亚等地均新发现了明显的化石足迹。(1)这些足迹地点的地层层位除野尻湖外,大多集中在下更新世地层。即使在日本之外，上新世-更新世足迹的存在在世界范围内也很有吸引力，就像东非的莱托利和美国西德克萨斯遗址一样。(2)沉积学上，所有这些足迹都具有嵌入在干湿条件下沉积的薄层交替粉砂中的特征，其中夹有粗砂。因此，足迹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，可以部分地识别寄主动物。例如，晚更新世的瑙曼象Paleoloxodon naumanni的足迹图案可以与早更新世大象Stegod onaurorae的足迹图案区分开来。

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.