In 1807, President Thomas Jefferson signed legislation calling for a survey of the United States’ coastlines. Initially coordinated by the U.S. Navy, the survey was taken over by the newly formed civilian U.S. Coast Survey team in 1832. Led by superintendent Alexander Dallas Bache, a U.S. Coast Survey team erected two base markers, each weighing over 3.5 tons, on Key Biscayne in 1855. The team established a 3.6-mile baseline that was used with other surveys to create some of the first truly accurate maps of the Florida coastline and reefs. The north marker is on land now within the Crandon Park Golf Course. The original south marker stood on land 300 feet south of the Cape Florida Lighthouse, but shoreline erosion had carried it into the sea by 1883. In 1988, local professional land surveyors located remnants of the southern marker in 12 feet of water, and the U.S. Air Force 301st Aerospace Rescue and Recovery Squadron recovered it. That effort preserved physical remains of the Coast Survey team’s struggle to measure and map Florida’s coast.