A Study on Footprints of Pliocene-Pleistocene Land Mammals.

对志贺的Yasu河、岩手的花崎、新泻的Koshiji-machi和兵库赤石市的海岸等哺乳动物足迹地分别进行了地层学、年代学和古环境调查。此外，模式分析也是对FOSE化石足迹研究的一种尝试。在研究过程中，在大阪东大林市石川河床、长野Nojiri湖湖底以及日本和印度尼西亚等地新发现了明显的化石足迹。(1)这些足迹地点的地层层位除Nojiri湖外，大多集中在下更新世地层。即使在日本以外，上新世-更新世足迹的存在在世界范围内也是引人注目的，美国东非和西德克萨斯的Laetoli遗址也是如此。(2)这些足迹在沉积学上都具有埋藏在薄互变粉砂和干湿条件下沉积的粗砂夹层中的特征。因此，足迹的形成可能与特殊的时代和空间环境有关。(3)通过对化石足迹的模式识别，部分识别宿主动物成为可能。例如，瑙曼大象晚更新世的足印图案可以与早更新世大象的足印图案区分开来。

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.