佛罗里达州，莱昂沉洞地质区的巨石区的漏斗盆

just south of Tallahassee in the Apalachicola National Forest, the Leon Sinks Geological Area is a premier example of karst topography, featuring sinkholes, natural bridges, and underground streams. It offers nearly six miles of trails, including the 3.1-mile Sinkhole Trail, which highlights deep wet sinkholes (like Big Dismal) and dramatic dry depressions. A layer of limestone underlies the land in this area, eroded and dissolved by rainwater and groundwater, forming caverns, holes, and tunnels. This type of terrain is called "karst" and results in many geological features such as wet sinkholes, depressions, natural bridges, and a disappearing stream.