Post Office Building, 1884
From Commercial and Architectural St. Louis by George Washington Orear (1888). This depicts the Customs House, one of the most solid structures in the city. The building's foundations rest on granite slabs, which in turn rest on granite blocks that were placed into cores excavated to bedrock. It was constructed during the latter part of the 1870s and into the early 1880s. During the late 19th century, virtually every federal office was located in the building, from railroad mail marshals to U.S. Marine hospital services to the U.S. signal service, which operated an observatory for a time from the dome. The Customs House (now known as the Old Post Office) has been renovated; more information is available at [Built St. Louis].