43 
formation and partial obliteration of craters and lava fields. 
Horizontal and vertical scales, 1.1200. 
No. 53. — Geological relief map of Mount ^tna. 
No. 54. — Geological relief map of Vesuvius and Monte 
Somma. 
No. 55. — Geological relief map of the Island of Palma. 
No. 56. — Geological relief map of the Island of Teneriffe. 
Maps of Ideal Reliefs. 
No. 61. — Relief of a volcanic island. 
No. 62. — Relief of a steep coast and dune coast, showing 
the two principal types of sea coast as they appear at ebb tide. 
No. 63. — Relief of a complete glacier. 
No. 64. — Relief illustrating the forrnation of valleys by 
erosion. 
Several globes are exhibited, one being four feet in diameter. 
Among the wall maps shown may be mentioned: 
No. 70. — Topographic wall map of a portion of the west of 
Scotland, hatchured. Scale, 1 in. equals i mile. 
No. 71. — Same as above, without hatchures. 
No. 72. — Bacon’s library wall map of London and suburbs. 
No. 73. — Geological wall map of England and Wales. Scale, 
I in. equals 15 miles. 
No. 74. — Hotchkiss’ geological wall map of Virginia and 
West Virginia. 
No. 75. — Geological map of Russia. 
No 76. — Map and profiles of the main drainage channel of 
the Sanitary District of Chicago, from Chicago to Joliet. 
A complete series of the topographical maps issued by the U. 
S. Geological Survey is deposited in the Departmental Library, 
and can be examined on application to the Curator. 
