In the middle of October, 1936, in compliance with Seisin-fu, the present writer made topographical, geological and hydrological surveys in the district of the so-called Yujyo-plain near Seisin, in order to supply the water for drinking and industry which was thought to attain a great quantity in future. Topographically, the southern boundary of the district is limited by Japan Sea, while the other three are bounded by the tectonic lines found in the mountain region. So the district can be called as one of the depressed basins which are often seen in the eastern coastal region of Korea. On the geology of this area, Mr. S. Simamura, of the Geological Survey of Chosen, already made a report according to which the geology of the region may be divided as follows (in an ascending order) :
In August of last year the writer obtained mammoth remains found at Iyasaka-mura, Manchuria. The description of the specimens, with a reference to their distribution in Manchuria, is briefly as follows: Tusk: Both ends are broken and lost. Length along the curvature 1.7m, while the distance between two ends 1.2m. Diameter 24cm at the top and 29cm at the base. The specimen is brittle and stained with a bluish tint. Tooth: The state of preservation is bad, and the greater part is extremely worn out. The unworn surface is blackish in colour. The grinding surface is oval, with length 105cm, maximum width 90mm, and height 117mm. The specimen consists of ten ridges, the interspaces between them being about 7mm in breadth. The thickness of the ridges is 7-8mm, and the enamel layers are 1.5mm in thickness, and their cross-sections show remarkably wavy plaits characteristic of this species. Mandible: Broken part of a mandible, 38cm long and 14cm broad. The above specimens may be determined from these characteristics as belonging to Elephas primigenius (Blum), and considering the ‘Blagovyeshchensk Geological Map’ and other literatures, they were probably derived from the recent deposits (sand, clay and gravels) of Upper Diluvial age. Mammoth fossils have frequently been found in many places of Manchuria and Siberia. The localities of the specimens kept in the Harbin Museum and those described in the previous literatures are given in the annexed map. A glance at this map will show us that all these mammoth remains are, except Dairen (N. Lat. 39°), distributed further north of North Latitude 42° of Manchuria and North Latitude 46° of Sakhalin (No occurrence has hitherto been known in Korea). This fact should be considered as very important in the palaeogeographical study of Eastern Asia.
Lately the writer obtained a mammoth tooth found on a seabeach between Nokoro and Tirie in South Sakhalin. The degree of fossilization of the present specimen is fairly high, chocolate brown in colour with a strong lustre. In the crown view, the outerside is an acute triangle, and the side view is nearly a rectangle. It consists of seventeen ridges, excluding several ones which are inferred to have been lost on the occasion of digging. Of these the anterior ridges are almost straight in the sideview, while the posterior ones are more or less curved, some of them being S-shaped. The grinding surface is flat. The enamel layers are flexuous, but nearly straight; in this respect they differ from those of Manchurian Mammoth. This specimen is perhaps the third molar on the left mandible. Length of crown 205mm. Ridges 17 Max. width of crown 80mm. Interspaces of ridges 5mm Length of grinding surface 115mm. Thickness of ridges 5mm± Height 120mm. Thickness of enamel layers 1.2mm± Height of crown 80mm . Frequency 10± The present molar is determined from these measurements to belong to Elephas primigenius (Blum). In many respects the sample has a close resemblance to that described by Mr. Sasa and thus it is considered to have been derived probably from the Rukutama Series of Upper Diluvial age. The present specimen will add one valuable material to the problem upon the palaeogeographical connection between Sakhalin and the Asiatic Continent in this age.
Bakawa-Ferry-Nakata Barrier, also called Kurihashi Barrier, was named after the two places, Bakawa and Nakata, because it was situated near a ferry of the Tone-gawa going from Kurihashi (Saitama Prefecture) to Nakata (Ibaraki Prefecture). It was established there because on the east there was the great plain of Kwanta, while on the west there were several barriers like those of Hakone, Kobotoke and Usui. The purpose was to secure the public peace and order in Yedo (Tokyo). The barrier above mentioned was, as shown in the picture, surrounded with a wooden fence, 14 ken in length and 15 ken in width, in the center of which there stood a barrier-office covering about 16 tsubo in area, guarded by four armed soldiers, who in turn watched on the passengers who went through the barrier. As in all barriers, women and those carrying weapons were closely examined at this barrier. But those who were most severely examined were the so-called “coming-in-gun” (iri-teppo) and “going-out-woman” (de-onna). This indeed was to prevent guns entering Yedo which were considered to break its public peace and order, and wives or daughters of feudal lords who were forced to stay at Yedo as hostages, and this was the policy of the feudal government.