Vesuvius, the Tengger Mountains and the problem of calderas

Until recently there was no good general map of the Tengger Mountains, so that in 1914 F. von Wolff (bibl. 1) in his work „Der Vulkanismus”, vol. I, p. 510—511, gives a reproduction of Pr. Junghuhn's map of 1844. For a volcanic district that has frequently been used as an example of a caldera and has been made familiar by the beautiful photographs from the firm of Kurkdjan in Soerabaya, this is an inadequate treatment, especially as Junghuhn's map is not accurate. After I had gained a superficial knowledge of the Tengger Mountains in two excursions in 1918 and 1919, I conceived the plan of making a new general map after the topographical map 1/20.000 of the Netherlands Indian Topographical Service. In 1922 I drew a wall-map 1/20.000 with contour distance of 100 meters, and coloured according to K. Peucker's method (Farbenplastik) (bibl. 2) the preparation of which occupied about a month. Plate 5 is a reduction of this map to 1/100.000, made by the firm of Smulders in the Hague, to whom a word of praise is due for the excellent way in which they have carried it out 1).