Divers call them Hells Bells, after the song by the Australian hard rock band AC/DC.
Hells Bells are usually circular or elliptical, but they do not form a complete ring.
The open portion of the cone always faces towards the cave walls.
Their walls are up to 3 centimeters thick.
These two layers do not mix and are separated by a partially mixed layer called the halocline.
Hells Bells are found at the margin between the halocline and the freshwater layer above.
The Bells do not cross into the saline layer because calcite dissolves there.
The Bells are also exceedingly old.
Radiometric dating indicates that they started growing some 5,000 years and the process continues to this day.
