"Geological Map of the State of Iowa", Mills & Company
Period: 1870 (dated)
Publication: Report on the Geological Survey of the State of Iowa
Color: Hand Color
18.1 x 12.8 inches
46 x 32.5 cm
This map was included in Charles A. White's Report on the Geological Survey of the State of Iowa, and is the earliest map to depict the geology of the entire state. 8 different geological types are identified by hand color including cretaceous, coals, subcarboniferous and devonian. In the northwestern portion of the state, bedrock is obscured by Pleistocene glacial deposits and is left uncolored. In addition to the geology, counties are delineated and major rivers and railroads are depicted.
References: Marcou & Marcou #468.
A pristine example. Issued folding.