This colorful lithographed geological map, produced by the eminent American geologist James Hall, blends science and the art of cartography. Twenty-three geological types are named and differentiated using hand applied color. The map covers the region of the United States from its western boundary along the Mississippi River, east to Long Island and the Atlantic. It includes all or parts of Wisconsin, Illinois, Missouri, Kentucky, Virginia, Indiana, Ohio, Michigan, Pennsylvania, New York, New Jersey, Maryland, and Delaware. The lakes Michigan, Huron, Erie and Ontario are shown. Lithographed by Endicott of New York and signed in the plate by James Hall. A very nice example of an early and scarce geological map. Blank verso.

This important regional geological map employs the "New York System" of stratigraphic nomenclature developed by Hall and others at the New York Geological Survey. This system emphasized the importance of paleontology for delineating geological units and introduced the concept of "type locality," a primary reference location used for defining the characteristics of geological formations. This map is the first regional application of this new system, which evolved into the standard nomenclature used today for North America and much of the rest of the world.

References: Marcou #32.

Condition: B+

Issued folding with bold color and light toning at top and in the upper right corner where the map folds into the report. Narrow right side margin, as issued.