A large and colorful map that was completely redrawn from the earlier editions that included information identifying railroads, roads, canals, army arsenals and forts. This edition eliminates much of this information and instead focuses on the geology. A table at lower left provides an explanatory key to the colors used to indicate nine distinct geological formations. The carefully drawn map shows good geographical detail as well as the remarkable geological information. Lithographed by Julius Bien.

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Condition: A

Bright original color. A trace of offsetting at lower left in blank area, slight discoloring at margin along centerfold, still very good.