Glad to see you guys are getting together over there.
A sectional rendering of the present day sinkhole.
I used to dive there and shoot video and cine for Sonny C0ckerell, State Underwater Archaeologist with the Florida Division of Archives in the late '70's.
Sonny C0ckerell with an unnamed friend
Really strange dive, particularly at the bottom circumference of the sink beneath the overhanging sidewalls. Passing by the ledge or relict "beach" shown in the illustration is pretty wierd too. There are long stalagtites around the circumference of the sink with caverns extending backward under the bank.
A video overview of the past of this unusual archaeological site in Florida. It includes extensive diving footage from within the sink. This is an artist's depiction of the spring during early man times with a much lower sea level. It must have been a startling sight, with steam coming out all over in cooler months from this craggy hole in the ground for pre-Columbian folk. A sectional diagram of the sinkhole, talus cone and relict beaches at depth.
CLICK image to be linked to video
A video of fairly recent free diving drop into the spring. The sulfur in the water contributes to the harsh green cast of the water.
From:
http://www.floridacaves.com/
.