Ross Prairie is a wetland surrounded by sandhills, where plants and animals live on ancient sand dunes left from a time when the ocean was higher. This landscape challenged builders of the Cross Florida Barge Canal, who called the stretch between Ocala and Dunnellon the canal's summit reach and planned a series of locks to lift barges up to five stories above sea level. In the 1960s, environmentalists opposed the canal in courts and in the media, and activist Marjorie Harris Carr successfully lobbied President Richard Nixon to suspend construction. A 20-foot-deep cut in the earth to the west remains from a failed 1930s effort to build a sea-level ship canal through these high lands. The Cross Florida Barge Canal had been considered for more than 100 years, was approved by Congress in 1942, received its first construction funds in 1963, and began construction on February 27, 1964, with President Lyndon Johnson on the site to give the signal. Supporters presented it as a 185-mile toll-free protected waterway across Florida from near Jacksonville to near Yankeetown, linking 26,000 miles of inland water in 29 states and promising transportation, flood control, water-table, recreation, and national defense benefits.