I08 NEW YORK STATE MUSEUM 



of titaniferous ores among the igneous areas of southern Norway, 

 and one of considerable magnitude at Routivara in Swedish Lap- 

 land. 



A third group of ores which may be mentioned to complete the 

 list, consists of the lake and bog limonites so frequently cited in the 

 literature of ore deposits as instructive examples of present-day 

 processes in ore formation. They are said to have furnished the 

 first material for iron manufacture in Sweden. With the improve- 

 ment of methods for working and treating the magnetites, the lake 

 deposits have lost their importance and are no longer employed in 

 the furnace. 



While it is purposed to give particular attention to the geological 

 features of the magnetites, some information on the industrial side 

 will be useful perhaps for comparison with the present situation of 

 iron mining in this country. 



Of the two main districts in which the magnetites are distri- 

 buted, central Sweden has long been and still is the support of the 

 Swedish metallurgical industry. The deposits of that district are 

 characteristically low in phosphorus and sulfur and the mine out- 

 put is consumed locally in the manufacture of charcoal iron for 

 which a wide demand still exists in spite of the development of 

 methods for refining the ordinary product of coke furnaces. 

 Mining there may be said to enjoy certain advantages that are not 

 apparent in this country. The greater value of the ores as com- 

 pared with those of usual composition admits their profitable ex- 

 traction from small deposits and the expenditure of more labor in 

 their preparation for the furnace than is economically practicable 

 elsewhere. In the work '' The Iron Resources of the World." re- 

 cently issued by a committee of the Stockholm Congress, F. R. 

 Tegengren places the number of active mines in central Sweden in 

 1908 at 277 and the total production of ore for the same year at 

 1,884,451 metric tons. In the total are included 262,620 tons of 

 concentrates from 23 plants. When it is considered that about 

 one-half of the product consisted really of high phosphorus ore, con- 

 tributed by the Griingesberg and one or two other mines which are 

 exceptional to the district, it is seen that the individual workings 

 are very small. Such operations recall to mind the days of the 

 forge iron industry in this State, when the numerous small deposits 

 of the Adirondacks were actively worked with an individual out- 

 put perhaps of a few hundreds or thousands of tons a year. 



Some of the mines of central Sweden have been worked almost 



