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DIVISION OF ECONOMIC GEOLOGY. 
The collections in this Division are systematically arranged 
to show how the metalic and non-metallic elements of economic 
importance occur in nature, as minerals and ores, and to illustrate 
some of the processes used in the extraction, treatment, and appli- 
cation of certain metals. They are for the most part m.ade up of 
the collections transferred to the Museum by the Chief of the 
Department of Mines and Mining of the Exposition. 
This Division also contains, besides numerous metallurgical 
products — Hall 76 is entirely devoted to iron products, — a great 
variety of coal, petroleum, asphaltum, and combustible derivatives 
and products; rock sections, and borings from petroleum wells, 
cement, gypsum, salts, ochres, artificial fuels, and other material. 
Each room contains one or more groups, and each group is sup- 
posed to show the typical minerals and ores of the metal, or ele- 
ment after which the group is named. The element of predom- 
inating value gives its name to the group. Frequently the metal, 
or element, is present in only very minute quantities, and not to 
be seen by the naked eye, or even with the aid of an ordinary 
magnifying glass; as, for instance, in nearly all of the gold ores. 
The halls occupied by this Division are Nos. 67 to 80 inclusive, 
except Hall 76, Section of Metal-Working Industries. 
