Fossil Shark Teeth
I’m taking a different tack in this newsletter. Generally I write updates on shipwrecks, current events about shipwrecks, new discoveries of shipwrecks, or identifications of shipwrecks, and so on – all related to my specialty: shipwrecks.
Let’s go back a bit to my teenage years. I have had a strong and abiding interest in fossils. One of my prize possessions is The Fossil Book, by Carroll Lane Fenton. I asked for it for Christmas when I was fifteen years old. Naturally, I still have it – along with the other 8,500 books that I’ve read since then. I never throw away a book that I’ve read. Although my personal collection rivals the inventory of many public libraries (and is causing my house to settle more than my neighbor’s), I take great pleasure in being able to refer to books that have been such an important and fulfilling part of my life.
My collection consists of more than one hundred books on paleontology, geology, and archaeology (as well as many hundreds of books on other scientific subjects). In college I took courses in all three disciplines. My primary goal was to become a paleontologist. Then came the Vietnam war. I got drafted between semesters. Afterward, I had to work for a living, so my college education foundered. But I maintained my interest in fossils throughout my life.
That’s why a trip to the Cooper River in South Carolina to dive for fossil shark teeth meant so much to me. I went in the winter when the temperature was too cold for most wetsuit divers. I was comfortable in my drysuit. Visibility was one to two feet. Once slack tide passed, I found it nearly impossible to stop from being swept downstream with the raging current. But I stuck it out. During the course of a weekend I recovered more than a dozen fine specimens from the riverbed. They ranged in size from one to three inches.
Although the Cooper River is considered a hotbed for fossil shark teeth, I have recently been introduced to a more productive location: an ancient riverbank off South Carolina. Rob Penn discovered this area several years ago. He was spearfishing on an offshore ledge that was a prehistoric coastline during the Ice Age, when so much water was bound in glacial ice that the shore was more than forty miles east of its present position.
A woman on his boat recovered a curious triangular-shaped rock. She showed it to Rob, who immediately recognized it as a tooth. And not just any tooth, but the tooth of a megalodon.
Megalodon sharks – the biggest sharks that ever lived – roamed those ancient seas for millions of years. Their skeletons were cartilaginous instead of bony, and were too soft to remain intact to become fossilized; they quickly dissolved into their component chemicals. Their teeth were dispersed by currents and tides, but were hard enough to survive the millennia.
A tooth consists of three major parts: pulp, dentin, and enamel. The soft pulp covers chambers and root canals in the jaw. It is surrounded by a hard material called dentin, which is calcareous (containing calcium). Dentin is coated with enamel that protects the interior parts from the constant grind of chewing.
These megalodon teeth practically carpeted the primeval riverbed that is now the distant seabed. Rob found the greatest concentration of teeth among coral heads on ledges that were formed when long-ago waves washed away the banks of an ancient watercourse. And that was where he took me, on his boat that he appropriately named the Play Penn.
It wasn’t the greatest day to be at sea aboard a 25-foot center console boat, with no protection from the sun, wind, and spray. It was crowded with six people, tanks, and dive gear. But hey – we were guaranteed shark teeth.
Rob – the original offshore megalodontist – anchored the boat and dived alone to 100 feet to find a productive area, leaving his ten-year-old son Kyle to work as topside crew. Rob returned with a couple of fine specimens. Then the first team descended. Mike Moore and Chris Campbell also surfaced with fine specimens. Then it was my turn. My buddy was my longtime soul mate, Pete Manchee.
My first dive was almost disappointing. I was thirty-four minutes into digging through gravel before I found my first tooth. But what a tooth! It measured six inches in length. Five minutes later I found my second tooth. Despite breathing nitrox, by then it was time to decompress. Pete and I ascended, and did half an hour of decompression
The meteorologists fumbled the forecast. Fifteen-knot winds and moderating two-to-four foot seas grew worse instead of better. By half time (surface interval), the winds were up to twenty knots and the seas were four to five feet. We toughed it out.
Rob decided to look for a new location. He dived alone, pulled the hook, then dragged a buoy line around the bottom while scouting for another productive area. This time the depth was 110 feet. Again he returned with teeth. We live-boated instead of anchoring. Mike and Chris went down the buoy line, dragged it around with them, and brought back some more teeth.
Pete and I descended. The buoy weight had dragged across the bottom. We took the weight in hand and followed the drag mark until we found coral heads – a distance of several hundred feet. Pete spotted the first tooth exposed. So we hunkered down and commenced to dig in the locality. This time we did much better. I found nearly a dozen teeth ranging in size from three to four inches. Pete found a fossilized whale vertebra. Whale rib bones were scattered everywhere.
The water was warm (77 degrees on the bottom, 83 degrees on the deco), calm, and ambient light visibility exceeded 25 feet. I was satisfied with the “take” from both dives. After another half hour of decompression, we surfaced into raging seas: honest six-footers that were steep and close together. Whitecaps were everywhere, making the sea look like surf, or perhaps a field of cotton that was waiting to be picked. It made for a tough ride home.
We stayed in our wetsuits. Rob and Pete took turns at the helm. At times the boat was airborne as it flew off a crest into a trough. Flying fish took wing at our approach. Dense spray struck me constantly in the face, and worked its way between my clenched lips. I found myself constantly spitting salt water from my mouth. We endured this torment for three solid hours. After twelve hours at sea in an open boat, I was totally exhausted.
But it was worth it!
