This scarce map, published by John Melish, was issued in William Maclure's report, Observations on the Geology of the United States. Maclure, known as the "father of American geology," published the first widely available geologic map of the United States in 1809. And while this is the third issue of the map (1809 in Philadelphia and 1811 in Paris), it is "generally considered as the starting point for the geology of North America" (Marcou & Marcou). The map is color-coded to indicate the location of Primitive Rocks, Transition Rocks, Secondary Rocks, Alluvial Rocks, and Old Red Sand Stone, based on the Wernerian classification system. Also keyed to the legend is a "line to the westward of which has been found the greatest part of the Salt & Gypsum." The map is filled with information on Indian tribes, forts, roads and early settlements. Illinois Territory is located well away from Lake Michigan and bounded on the north by the large North West Territory. Chicago is correctly located, but is on the border between Indiana and North West Territory. Of particular interest are distance notations along several major roads in miles. A legend locates canals, boundary lines and roads.

The map is still bound to the front of the volume and includes an additional folding plate showing five elevation profiles originating in the Appalachian Mountains. 127 pages, hardbound in black quarter leather and tips over marbled boards.

References: Marcou & Marcou #27; Howes #M161; Sabin #43552.

Condition: B+

The map is lightly toned with a few manuscript pencil marks in the image and several small fold separations that have been closed on verso with archival material. The text and additional plate at back is very good with light scattered foxing. Covers are moderately worn and stained. The inside front cover contains an old library bookplate.