Geology
The cutaway, limestone sides of the sinkhole provide an easily visible geological record of the area. Twelve springs, some more visible than others, feed the pond at the bottom of the sinkhole. In the summer, the bottom of the sinkhole is dramatically cooler than the air at the surface due to the depth and shade from the canopy above. Significant fossil deposits include shark teeth, marine shells, and the fossilized remains of extinct land animals.
Read more about this topic: Devil's Millhopper Geological State Park