The 1850s expansion of the Capitol included both much-needed offices and committee rooms for the Congress as well as grand public stairs, lobbies, and corridors. The passage from the east portico to the new Senate chamber was one of the most elaborate interiors in the Capitol extension. Columns with corn leaves, tobacco leaves and magnolia flowers blended into the Corinthian capitals were especially elegant features. The pattern of the marble floor was simplified when it was installed during the Civil War.
Architect of the Capitol