Geographical Notes

Abstract

MR. WADA, of the Japanese Legation in Berlin, recently laid before the Geographical Society there certain maps produced by the Geological Survey of Japan, which represent the work up to the present of that establishment. It was founded in 1879, and was organised by Dr. Naumann, a German geologist. It consists of topographical, geological, and agrenomical sections, and of a technical and chemical laboratory. The maps prepared by the department for the Geological Congress of Berlin this year were:—(1) An oroplastic map, on a scale of 1:860,000, showing the general position and form of the Japanese archipelago, the coasts, ranges of mountains, as well as the depths of the ocean off the coast. (2) A magnetic map. During the preliminary topographical survey magnetic variations were investigated by the help of a portable magnetometer. Magnetic investigations are of extraordinary interest in Japan. The maps show that the variations are frequently very different in kind, the numerous volcanoes causing great irregularity. (3) A geological map constructed from the preliminary surveys of Dr. Naumann and native geologists. This is based on a topographical map, which is not reliable in detail; but it shows the knowledge attained so far of the geological structure of Japan. From this it appears that all the formations are met with in that country, the Palæozoic being universal. Next to these in extent comes granite. A complete report on this subject is to be made by the head of the Survey to the Congress. The topographers have worked now for about four years, and the area surveyed is more than eighty geographical miles square, The completion of the maps for the whole country will take another eight years. The detailed geological survey has reached about the same extent as the topographical survey, but none of the sheets of the map have yet been published, although they exist in manuscript down to the 38th parallel, with the exception of Yezo. The maps, as well as the text, appear in Japanese and English, and the Survey publishes also annual reports, eight of which have already appeared, but only in Japanese, Another map, also prepared for the Congress, is one of the volcanoes, the ages being distinguished by colours. An important portion of the work of the Survey is the study of soils. According to Mr. Wada, a volcanic tufa, consisting for the most part of decomposed silicates, forms a large part of the numerous uncultivated plains at the foot of the mountains. An accurate knowledge of this will be of much value to agriculture. Japanese soils in general are stated to be poor in chalk. This subject will also be dealt with by the head of the Agronomical Section before the forthcoming Congress.