Engraved copper plates used to print topographic maps

AZGS received dozens of engraved copper plates used to print topographic maps of Arizona. The plates are being surplussed to states and universities by the USGS which no longer uses them for producing maps.  After cleaning, we hope to put selected plates on display to demonstrate how maps used to be made, one layer (eg, topography, hydrography, streets) at a time.  They are also stunningly beautiful.  The plate at right is from the set used for the Grand Canyon.