The only access to the spring is by boat. The banks are steep and heavily vegetated. Black Spring is also known as Black Hole. The pool is about 90 ft in diameter and 75 ft deep and its sides are nearly vertical. The water is jet black, making it impossible to see the bottom.
Local residents report that the vent is near the center of the pool.
The north run has an average width of 50 ft with depths from 2 to 10 ft. It flows north about 300 ft, bifurcates around a delta-shaped wooded area, and empties to the east into the clear water of Spring Lake. Black Spring and the other springs of Jackson County are in the drain- age basin of the Apalachicola River. Analyses by U.S. Geological Survey. Units are in milligrams per liter unless otherwise indicated.