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A plaster cast of "slickensides," parallel striations on rock surfaces produced by relative motion across opposite sides of fault planes, along the Hayward Fault at the U.S. Geological Survey Map Center in Menlo Park, Calif.
Cartographer Mitch Adelson of the U.S. Geological Survey in Menlo Park, Calif., sells topographic maps such as this to visitors from all parts of the country.
U.S. Geological Survey
The U.S. Geological Survey in Menlo Park, Calif., houses rows and rows of maps of fault lines in the U.S.