6o FIELD MUSEUM OF NATURAL HISTORY 
ores of the metal arranged in order of their richness. Each of 
these is accompanied by a group of the materials of which the 
specimen is composed, so arranged as to show plainly the com- 
position of the specimen. With the type specimens and making 
up the bulk of the collection are shown specimens of ore from 
different localities arranged in geographical order. Specimen 
labels show the mineral of the ore and the amount of metal con- 
tained, where this is known. It should be remembered that 
many of the ores produce more than one metal, in which case 
the specimen is placed in the group of the predominating metal. 
Entering the hall from the West Dome, the visitor should 
keep to the left, following along the walls until the starting point 
is reached, when the large specimens along the center of the hall 
may be examined. 
Upon the walls are three relief maps of the United States 
illustrating respectively the distribution of copper, zinc, and 
iron ores. The location of an ore deposit is represented by a 
specimen of the actual ore placed in proper position on the map. 
As the mountains are represented in relief upon these maps, the 
relationship of the different kinds of ore to the relief of the land 
becomes evident and may be profitably studied. 
COPPER. 
Entering the hall from the West Dome, the copper ores are 
to the left. They fill six wall cases and the two adjacent floor 
cases. The first wall case contains the copper-bearing minerals 
arranged in the order of their richness. 
On the lower shelves of this case is a collection of the copper 
ores of the Appalachian mountains. 
The following wall case contains a collection of native copper 
and silver and the minerals which are associated with the cop- 
per of northern Michigan. The crystallized copper and the 
calcites are especially noteworthy. 
The two following wall cases, in the northwest corner, con- 
tain copper ores from the western United States, chiefly the 
Rocky Mountains. The copper ores of this region usually carry 
gold or silver, and many localities producing a very consider- 
able output of copper are represented among the gold ores of 
Hall 72. 
Immediately in front of these cases are two table cases with 
large specimens of the copper ore from Keweenaw Point, north- 
