Hours of Operation Florida state parks are open from 8 a.m. until sundown 365 days a year. History Devil's Millhopper gets its unique name from its funnel-like shape. During the 1880's, farmers used to grind grain in grist mills. Because fossilized bones and teeth from early life forms have been found at the bottom of the sink, legend has it that the millhopper was what fed bodies to the devil. Hence, Devil's Millhopper.
Limestone is the foundation on which the surface of Florida sits.
Although this stone is very hard, it is easily dissolved by a weak acid. Rainwater becomes a weak carbonic acid from contact with carbon dioxide in the air. As it soaks into the ground, passing through dead plant material on the surface, it becomes even stronger. When this water reaches the limestone layer, small cavities are formed as the rock slowly dissolves away. This process continues over a very long time until a large cavern is formed.