DEPARTMENT OF GEOLOGY 
61 
In the two adjacent floor cases are large specimens of man- 
ganese ores. 
Upon an adjacent base is a large specimen of Brazilian man- 
ganese ore which weighs 3,300 pounds. 
IRON. 
Iron ores fill five wall cases and two floor cases. 
Foreign Iron Ores . — The case following the manganese ores 
contains iron ores of Europe, Australia, South America and 
Mexico. A full collection of iron ores and surrounding rocks 
of the Cerro Mercado or Iron Mountain, of Durango, Mexico, 
shown here, illustrates a valuable occurrence of an important 
but little understood type of iron-ore deposit. Large specimens 
of a specular hematite from the state of Minas Geraes, Brazil, 
in the lower portion of the case, illustrate a micaceous hematite 
of world-wide distribution. Many of the ores in this case are 
from deposits almost unknown to the world at large. 
The adjoining case contains a complete collection of the ores 
and surrounding rocks from two iron ore deposits of eastern 
Russia. Better known ores represented here are those from Eng- 
land and Sweden. German ores are represented by fibrous hem- 
atites and limonites and the well crystallized “sparry” siderite. 
Domestic Iron Following the foreign ores is a case 
of iron ore from the Lake Superior region. The ores in this 
case are from the most important iron ore mines of the world. 
It is to the proximity of these remarkably rich and pure ores 
that Chicago owes its present importance in the iron and steel 
industry. The ores are arranged in the cases under the several 
“ranges” as the iron mining districts around Lake Superior are 
termed. While similar in many respects, differences between 
the ores of the several ranges may be noted even in the small 
specimens here shown. Specimens of a local magnetic iron sand 
are worthy of attention as coming from the immediate vicinity 
of Chicago. 
The cases following the ores of the Great Lakes region con- 
tain iron ores of the Eastern States. These are here represented 
largely by limonites and hematites from Virginia and the im- 
portant southern districts near Birmingham and Sheffield, Ala- 
bama. Magnetic ores from New York, New Jersey, and North 
Carolina represent another important class of eastern ores. 
