Fossil City, Northwest Florida
by Ron Bear

Fossil City, a very unique cave diving experience. Weekend Report.

Hi All,
On Saturday we went to Jackson Blue and explored a side passage at 800 feet. I led the way into this side passage. It was about thirty feet wide and two feet tall. I just couldn’t stay out of the silt. I felt like an ox. I could see that the passage continued a ways, but I was silting my buddies out pretty bad. I wanted to continue, but I felt really bad knowing that I was the only one who could see anything. I made an effort to be a little less of a klutz, but even while concentrating intensely, five feet later I felt my thigh scrape through the silt. At that point I decided that it wasn’t worth dragging my buddies into such a potentially hazardous environment just so I could see a few more feet of cave. (It is ok if it means we ALL see a few more feet of cave). To turn that dive, I had to turn sideways and wait for Kim to crawl through about five more feet of silted out passage so I could stick my thumb in her face. John later reported that his first indication that the dive was over occurred when Kim shoved her thumb right into his mask. On the way out of this passage we realized that we had not chosen the best angle to enter it. The next time we dive this side passage we will probably get about thirty feet farther before silt even becomes an issue. The other good thing that came of this dive is that we took some measurements of the six-way intersection at 300 feet on the way out.

Sorry for kind of rushing through that one, but I am very anxious to tell you about Sunday. Sunday was adventure day. Kim couldn’t go, so John and I grabbed our friend Tim and headed to the Choctawhatchee River. John knew about this spring out in the river and we were going to go check it out. We put the boat in under the bridge at 20. On the way up the river we talked about the various rumors we had heard in relation to this spring/cave. John had heard that there was a grate across the mouth that blocked all access. Why would anyone put a grate across a cave in the river? Tim had been told that this cave was full of sharks’ teeth. I related my experiences about rumors and caves, and we all agreed that we would be very grateful to find a cave there at all. After we arrived and started gearing up, some other folks pulled up and started telling us what they knew about this spring. They told us that this spring had always been referred to as Spring Run, Spring. I used to go to a cave called Cave Hill, Cave so I don’t doubt that this is what it is called. I am not the discoverer of this place, so I have no right to rename it. I can however think of it in any way that I choose. For reasons that I will make clear later I choose to think of it as Fossil City. The other thing that these nice folks told us is that we should be very careful because nine different people had drowned at this spring over the years.

The Dive
I tied my 400-foot reel off to a tree, and headed towards the hole that all of the water was gushing out of. As I approached the entrance I began clinging to anything I could find to keep from being blown backwards. I hadn’t even made it out of the basin yet, and I am thinking that if I can’t find another handhold, I don’t know if I will be able to make any more forward progress. Well look at that. There is a one half-inch nylon rope with knots every two feet going into this hole. I basically spotted it as soon as my eyes started to adjust. I tied my reel off to this line and started hauling myself in. Hand over hand with my body flapping like a flag in a storm. My regulators were both purging from the flow, so I had to bow my head to protect them from the blasting water. The rope was about thirty feet long, but the blasting flow only continued for about twenty feet until the cave opened up and the flow was distributed through a wider area and therefore moved slower. On the last ten feet of rope I found myself still tensely holding on in spite of the fact that the reason for holding on so dearly had suddenly diminished greatly. Once I pried my fingers from the rope and calmed down, the first thing I wanted to know was how much air I had lost from the flow purging my regulators. That is when I discovered that the flow had ripped my SPG from my hip and it was just dangling. John’s gear was also in disarray. His long hose was no longer routed under his canister light. These were just minor problems that we soon sorted out and then we tied a gap spool from the thirty-foot rope to the main line and started into the cave. We weren’t fifty feet in the cave yet when I started noticing fossils literally everywhere. There was petrified wood, shells, sand dollars, sea urchins and pieces of bone. As I saw more and more pieces of bone, I came to the conclusion that they weren’t bones. Rather they were teeth or tusks. I certainly could be wrong about this, but they seemed to be round in cross section, and curved along their length. Isn’t a rib bone the only curved bone, and aren’t they kind of flattened? Also beginning right at the mouth of the cave, there are these tubes. Perhaps someone out there can tell me what they are, because I certainly don’t know. They line both walls. They are usually hollow but sometimes filled in with clay or rock. The size of the tubes varied from soda straw to three inches in diameter. The walls of these tubes were about double the thickness of an eggshell. Almost every single tube was vertical, with the rare exceptions probably being broken off specimens. Note that the horizontal tubes were still fossilized into the walls, like they had been broken off and then frozen in place. Because they were so vertical, I’m guessing that they are some kind of plant fossil. Cane or bamboo comes to mind, but those have knots/joints every so often and these were smooth with a uniform diameter up their length. I don’t think I know how tall they are, because their height seemed to be a function of missing rock exposing a part of the height instead of height being a function of the original height of the tube. Enough about the tubes except to repeat that they were like wallpaper or wainscoting on both walls through the entire dive, which made this cave very interestingly decorated.

This cave would have been a fun and interesting dive even without all of the fossils everywhere. There was an intense flow in your face the whole way through the dive. The cave kept going up and down serpentine fashion from about 50 feet to 75 feet. On the way in I thought that this was going to be the worst sawtooth profile I had ever dove. To make progress, John and I finned continuously while also shoving our hands into the silt and pulling. If you picture the cave as a series of hills and valleys, then on the upstream side of the hills, we frequently found the slope to be covered with heavy coarse sand with big black specs in it. On the down stream side there was usually a lot of gunky silt with fossils lying all over it. There was something else lying on the silt besides fossils. Black rock half an inch thick in weird shapes. In places the cave was completely covered in a layer of black rock. In other places, the walls and ceiling were white limestone with black rock lying on the floor. At first I thought that the black rock was a sediment layer that had not been eroded away and been left behind when the limestone was removed. Later I realized that the black layer could not be a sediment layer because it conformed to the shape of the cave rather than to a depth. At some point in the past, after the cave had already been formed, this black stuff had been deposited on the cave walls and then hardened. All through the cave the black rock ranged from non-existent to patchy to all encompassing. I had seen this stuff at other caves, but I hadn’t seen enough of it to piece this all together. At a penetration of about one hundred feet, John pointed out a three-foot wide rock that had fallen from the ceiling and was pinning the main line. All he was doing was telling me to make a mental note in case we ended up coming back this way in a silt out. At a penetration of about four hundred feet, John suddenly stopped moving forward. It turns out that he had lost track of the line and feared that it had stopped and I was heading in with no guideline out. The line was there of course. He had just missed the discolored line in the crummy vis. At a penetration of around five hundred feet, I noticed a big pile of bones. It had several very large tusks in it and one vertebra the size of my hand. I was thinking that there might be a whole skeleton of something here if I could just figure out how to piece it together. Meanwhile John continued to struggle forward. I wanted to show this pile of stuff to John, but I didn’t want to move any of it because the rest of it might be right there somewhere. As he got about thirty feet away and his light started to fade away, I needed to make a decision. What I decided to do was place a clothespin on the line to mark the spot of this little bone yard and show it to John on the way out. When we had been going into this cave for thirty-five minutes, finning hard and using our hands as well, I called the dive on thirds. John told me later that he had been about to call the dive on fatigue. We were worn out and quite happy to allow the current to swoosh us back through the passages with little to no effort on our parts. Now recall that on the way in we had been going up and down hills. We left the cave at almost four times the speed that we came in, and our watches were almost constantly beeping at us that we had exceeded a thirty feet per minute ascent rate. They would just stop beeping at the bottom of one hill when we would start up the next and they would be beeping again. This was super fun! Also we had reduced the vis from thirty feet down to about fifteen feet. Have you ever noticed that when you run at night, it feels like you are going faster than when you run in the day? The low vis made this mad rush through the cave feel faster too. It was like some crazy roller coaster where you were constantly on the verge of slamming into the ceiling or floor. Up and Down and Swoosh and Beep-beep, beep-beep, and Swoosh and Glide! Don’t even talk about using your fins. Every time you made the slightest ankle movement you would shoot forward even more. I felt like I was ready to race a cheetah. When we got back to my clothespin, I quickly relocated that pile of bones. When I showed John the vertebra, he handed it back to me and I put it down. He then picked it back up and handed it to me again. (We turned around and finned the other way to hold position during this exchange.) John wanted me to take it with me. Well, I had to think on that. First off, the rule is you take nothing, so that others can enjoy the cave the same way you did. Secondly, if some archeologist where to try and find the rest of this thing it would be important to know where this had been. I decided to leave it in place. As I was thinking about it though I just hung motionless while studying this very interesting find. You all heard me describe the current. Raise your hand if you think that hanging motionless in this cave, results in a lack of motion. When I had made my decision, I looked down and left to the last place I had seen the line. It wasn’t there. I panned left and right looking for the line. There was no line. I froze and swept my line around the entire circumference of the passage I was in. This passage did not contain a line. I stuck my light up against my body and looked for John’s light. Nothing. How in holy crap had I managed to go from being in the main passage on the main line with my buddy to being alone in a side passage off the line in poor vis? This was forty minutes into our dive. Do you believe in ESP? On the surface, Tim was talking to those local folks I was telling you about. After we had been gone forty minutes, the lady asked Tim if he was starting to get a little nervous. He told me he had actually started to get a little nervous but denied it to her. I don’t believe in ESP, but you have to admit the timing here is kind of interesting. The short hair on the back of my neck never actually raises up when matted down by wet neoprene, but I could feel it trying. The first thing I did was allow myself to drift just a little further to positively establish which direction I was traveling. Then while making very good mental notes of where I was and where I was going, I reversed course. Within fifteen feet I saw a slight glow from John, and immediately afterward I saw my bone pile. I put the vertebra back and resumed swooshing down the passage. At around two hundred feet, I noticed a side passage. I knew we had been making very good time on the way home so I asked John if he wanted to go down it just for a look. On the way into the side passage we went up a very yucky silt hill. John stuck his finger in it, which is the absolute best way to positively establish the coefficient of yuckiness. This stuff was to be avoided like the plague. We started clinging to the ceiling to stay out of this stuff. Wrong move. Rocks started falling off of the ceiling into the silt. Also I had no formula to figure a safe gas margin for turn pressure as I had not noticed the side passage on the way in. Therefore I turned us around and we headed for the exit. When we reached the entrance chamber, we discovered that all of the silt we had been displacing had been kind of swirling around prior to being blown out the hole with the rope. The vis in this chamber was now about five feet. When we were both on the half-inch rope with all reels but the outside reel retrieved and stowed, I was ready to head out. I reached for the rope about twenty-five feet from outside… and woosh I barely managed to grab it three feet from outside before being forcibly thrown from the cave. Our safety stop was no fun. There is a large mound of very coarse sand/gravel spilling down into the raging flow. The flow tries to blow it uphill and downstream, but gravity tries to pull it down into the mouth of the cave. This stuff has reached a perfect equilibrium, which we did not disturb on the way in. On the safety stop however we were laying on this sand pile when the whole thing started sliding downhill. Well the flow was not going to let gravity beat it. The compromise between these two elemental forces was to have half the sand continuously sliding down the hill, while the other half was continuously being blown up over our heads and down the necks of our wetsuits. In seconds, the water turned into a tornado of sand, gravel, and leaves. The only consolation is that next time there will be about a pound less of this stuff, because that is how much of it I removed from between my skin and my wetsuit.

When we came up, the folks I told you about were still there talking to Tim and they took pictures of John and me. It turns out that they just live right down the road from me and they promised to give me some copies.

DSAO
Ron

If you would like to contact Ron, email him at ronald.bear@eglin.af.mil