The Lorraine district is on the French border and forms a part of the large ore field of Luxemburg and northern France. The deposits, of sedimentary origin and Jurassic age, comprise extensive beds of oolitic limonite varying in thickness up to 20 feet, interlayered with marl and limestone. Seven principal beds of ore are found within a thickness of sediments ranging from 75 to 150 feet, the most important being known as the Grey seam. The tonnage[31] of “minette” ore available in the German Lorraine district is estimated at 1,830 million[32] as compared with 300 million in Luxemburg and 2,975 million[33] in northern France. The “minette” ores average 30 to 40 per cent. in metallic iron content and 0.3 to 0.7 per cent. or more in phosphorus. [31] The ore reserves in this chapter are given in metric tons unless otherwise stated. [32] EINECKE, G., and KOHLER, W.: “Iron-Ore Resources of the World,” Stockholm, 1910. [33] NICOU, L., idem. The deposits of the Salzgitter and Ilsede districts north of the Harz Mountains are beds of brown ironstone conglomerate with an average thickness of 20 to 30 feet, consisting of limonite pebbles in a clayey or calcareous cement. These deposits cover many square miles, the reserves being estimated at 248 million tons. The ores contain 30 to 40 per cent. of iron and average 0.7 to 0.8 per cent. in phosphorus. The ores of the Lahn and Dill region are mainly red hematites, that lie in an extensive sedimentary bed. They contain about 48 per cent. of iron, 0.2 to 0.3 per cent. phosphorus, and are high in silica. The reserves are estimated at about 135 million tons. In Siegerland the iron ores are mainly carbonate, carrying 38 to 40 per cent. metallic iron and 6 to 9 per cent. manganese. They form irregular deposits abundantly scattered through the region, the available reserves being estimated at about 100 million tons. The total iron-ore reserves of Germany (not including those of Luxemburg) actually available have been estimated at 2,540 million tons, and the probable further reserves at 1,067 million tons. Of these amounts, however, Lorraine has by far the largest part, so that the transfer of this province to France reduces Germany’s available reserves to 28 per cent. of the pre-war figure, and her further probable reserves to one-half, altogether reducing her iron-ore resources to one-third of the former amount. As far as is known, the German iron and steel business is in the hands of German capitalists, who, besides, have important iron-ore holdings in France, Spain, Sweden, and elsewhere. Among the important iron-ore and pig-iron producing firms in Germany are Gutehoffnungshütte, de Wendel & Co., Krupp, Gebrüder Stumm, Aschener Hütten Aktien Verein, Rombacher Hüttenwerke, Thyssen & Cie., and others. All of these firms had large ore reserves in the Lorraine district when the war began.