exceptional example of an early buff-colored terra cotta keystone fabricated shortly after the great chicago fire by the chicago terra cotta company, chicago, ills. the ornamental exterior chicago commercial building keystone contains a nicely aged patina in the form of discoloration from prolonged exposure to the elements. the rear cavities have been cleaned from loose brick and mortar. the post-fire chicago building window hood keystone features a simple abstract floral motif. the fired terra cotta keystone was likely fabricated between 1872-1874.