million years of geologic time is represented in the wall of Falling Water Sink.
With the onset of the Pleistocene Epoch ice age about two million years ago, huge glaciers formed across much of northern North America. Although the glaciers never reached Rorida, sea water was locked up as glacial ice, and worldwide sea level dropped. The Falling Waters area once more became stranded inland, high above sea level.
The newly exposed land was attacked by the forces of weathering and erosion. Streams removed and reworked sediments lying at the surface. The underlying limestone was also subjected to dissolving or dissolution by rain water, made slightly acidic by absorption of atmospheric carbon dioxide and organic acids in the soil. This water preferentially circulated along natural fractures, joints, and more permeable beds within the limestone. For millions of years, this percolating water slowly dissolved a network of caves, caverns, and vertical solution pipes through the originally solid rock. In some caverns, enough rock was dissolved so that the overlying sediments were no longer supported. When this happened, the overburden collapsed into the cavern, forming a sinkhole. Such an event created Falling Water Sink. Sinkholes and other collapse depressions are very common on the terrain around Falling Water Hill. Such a depression-pocked landscape formed on limestone is called karst terrain.
Falling Water Hill, which attains a maximum elevation of about 320 feet above mean sealevel, is believed to be a remnant of a once more extensive highland area which spanned much of northern Florida. Over the millennia, extensive karst dissolution, coupled with erosion by surface streams, has lowered the land surface that surrounds the hill for miles in all directions. Today, Falling Water Hill stands as an erosional outlier, separated by lower terrain from hills of similar elevation to the west and south.
Falling Waters sink is situated on the south side of Failing Water Hill. The stream cascading into the sink is fed along its course by numerous small springs flowing out of the hill.