48 
Relief map of the region of extinct volcanoes in Auvergne, 
Central France; geological and topographical. Henri Le Coq 
and G. P. Scrope. 
Geological map of the Siebenburgen region, Bohemia, by 
Von Hauer. This map is an illustration of good coloring. 
Geological map of the state of New York. 
On tables occupying the floor of the hall will be found the 
following : 
Harvard geographical models, showing the effect of submerg- 
ence and elevation of a coastal region. 
Ideal relief of a complete glacier. 
Ideal relief illustrating the formation of valleys by erosion. 
Ideal relief of a volcanic island. 
Ideal relief of a steep coast and dune coast, showing the 
two principal types of sea coast as they appear at ebb tide. 
Geological relief map of Mount Aetna. 
Geological relief map of the Island of Bourbon. Scale, 
1 : 300 , 000 . 
Geological relief map of Blair, Bedford and Huntingdon 
counties, Pennsylvania. A portion dissected to show geological 
structure. 
Geological relief map of the Island of Palma. 
Relief map of a part of Mount Desert Island, Maine. Scale, 
1 to 40 , 000 . 
Relief map of Mont Blanc. Horizontal scale, %-in. equals 
1 mile. Vertical scale, 1%-in. equal 1 mile. 
Model showing irrigation by ditches and furrows on steeply 
sloping fields. 
Profile relief map of the Sentis Mountains, northwestern 
Switzerland, showing mountain contour and geological structure. 
A complete series of the topographical maps issued by the 
U. S. Geological Survey is kept in drawers beneath the tables, 
access to which can be obtained on application to the Curator. 
DIVISION OF ECONOMIC GEOLOGY. 
it IS the purpose of the collections shown in this Division to 
illustrate modes of occurrence in Nature of the minerals and 
ores which have economic importance, to show the localities from 
which they are obtained, the processes used in their extraction 
