Nineteenth-Century Fortifications Found on Alcatraz Island

News February 28, 2019

(Timothy de Smet)
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California Alcatraz Island
(Timothy de Smet)

BINGHAMTON, NEW YORK—NewYorkUpstate.com reports that archaeologist Timothy de Smet of Binghamton University and his colleagues explored California’s Alcatraz Island with ground-penetrating radar and laser scans, and found traces of a nineteenth-century citadel. The researchers also employed georectifications, which link old, digitized maps to a coordinate system in order to locate remains of historic buildings. Many of the military structures built on the island after the War of 1812 were destroyed when a prison was constructed there in 1908, but de Smet and his team were able to find an earthwork traverse and its vaulted brick masonry tunnel and ventilation ducts, built in the 1860s, just under the surface of the prison’s recreation yard. They had been covered with just a thin layer of concrete, de Smet said. To read in-depth about a Civil War prison in Georgia, go to “Life on the Inside.”

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