Rocks developed in Nasu plain and its circumference, Tochigi Prefecture, are devided in descending order as follows. 1) Holocene. a) Flood plain deposits, b) 4th terrace gravels. 2) Pleistocene. a) Brown volcanic ashes, b) 3rd terrace gravels, c) 2nd terrace gravels, d) 1st terrace gravels, e) Higher terrace gravels, f) Lava of Nasu-volcano, g) Kuroiso pyroclastic rocks. 3) Pliocene. Otahara pumice flow, b) Lava of Takahara-volcano, c) Ainosawa pyroclastic rocks, d) Yanagibayashi gravels. 4) Miocene. a) JiOhOji mudstone, Takaiwa taffaceous mudstone, c) Sekiya. group. 5) Palaeozoic. The permeability of water in each of the above mentioned layers is classified as listed below. Permeable : I) a), 1) b), 2) a), 2) b), 2) c), 2) d), 2) f), 3) b), 3 c). Imperfectly impermeable : 2) g), 3) a), 3) c), Impermeable : 4) a), 4) b), 4) c), 5). The configuration of the surface of imperfectly impermeable to impermeable layers in Nasu plain is determined by methods of the electric prospecting and the test boring. It is lower in the inside than on both sides of the destrict, indicating the impossibility of running out of ground waters from Nasu plain. The ground water in Nasu plain is supplied by permeated waters due to rains on the mountains and the plain belonging to the catchment area, as well as those derived from waterways and paddy fields. The quantity of supply amounts to about 8.8m3/sec. The permeability coefficient of the terrace gravels is 0, 0044 m/sec and the velocity of ground water is 1521 m/day.
During the field season of 1956-57 the Tokyo University Iraq-Iran Archaeological Expedition performed an excavation at a Neolithic site in Northern Iraq. Before the excavation I tried to get some knowledge of the physiography of Iran and also to collect as many fossils in Western Iran as possible. Physiographically, Iran may be divided into the following four zones : 1) the central plateau, 2) the coastal plain along the Caspian Sea, 3) the coastal plain along the Persian Gulf, and 4) the Khuzistan alluvial plain of Southwest Iran. Innumerable fossil remains, such as foraminifers, brachiopods, molluscs, and echinozoans, were collected from mudstone at an outcrop 7 km southwest of Qum and at a place 24 km southeast of Kashan. From their faunal assemblages, containing countless Lepidocyclina, the fossiliferous formation must be correlated with the Asmari, which is considered to be Aquitanian in age. The Maragheh region is one of the better known localities of Pontian Hipparion fauna and the fossil localities are scattered around the city of the same name. I visited one of them near the village of Karl Abad which is close to a ravine of Murdi Chai. In spite of only a few hours stay I fortunately managed to collect Trilophodon pentelicus (Gaudry and Lartet), Hipparion gracile Kaup, Aceratherium sp., Tragocerus sp., Gazella sp., and Chelonia gen. and sp. indet.from a nearly horizontal deposit of tuffaceous sandstone. Fossil remains of Maragheh must have been buried by volcanic ashes from the volcano Kuh-i-Sahand. The Hotu man was recently excavated from the cave-deposits near the southeastern corner of the Caspian Sea. It is supposed that the Hotu skeleton is intimately related to the human remains from Mt. Carmel in Israel and Teshik-Tash in Uzbekistan of USSR. Judging from recent radiocarbon dating, it becomes doubtful that the Hotu skeleton belongs to a Palaeoanthropic man. Siah Kuh mountain which is situated at the western extremities of a great desert, Dasht-i-Kavir, is very rich in invertebrate fossils, such as calcareous algae, foraminifers, bryozoans, brachiopods, molluscs, and echinozoans. From the occurrence of innumerable bryozoans in the limited horizon, these fossils may be collected from the Middle Fars and are considered to be Vindobonian in age.