Collecting fossils in Florida

Niels Laurids Viby (Denmark)

I didn’t go to Florida especially to look for fossils, but I am always looking for opportunities when I am abroad. Being an architect, I actually went there to study houses, in particular, the Art Deco district at Ocean Drive in Miami. However, it seems that every museum in the State (other than art museums) has a fossil exhibition: the Science museum in Miami was showing Chinese dinosaurs, the Orlando Science Centre had displays of Upper Cretaceous dinosaurs and the Natural History Museum in Gainesville had the very best – complete skeletons of mammals from Florida.

The result was that I spent a lot of time looking at things (including buildings) rather than finding fossils.

In fact, out of thirteen days in Florida, I spent three in or waiting for planes, four driving long distances (but with some stops checking out potential fossil sites), four looking at houses, one on paperwork for a report on buildings and only one full day looking for fossils. The time spent driving was a big surprise. Florida looks small on a map of USA, but all of Denmark (my home country) could fit into the area south of Gainesville and the Danish population is probably equal in number to half of the people living in Greater Miami.

However, I saw this trip as an expedition into unknown territory – a future trip will be different and better informed. But I did get some opportunity to look for fossils.

Fossil collecting in Florida

It is important to realise that, to collect fossils, you have to get a Florida Fossil Permit. Go to: http://www.flmnh.ufl.edu/natsci/vertpaleo/vppermit.htm and follow the instructions. Basically, you will need to fill in the form that you can print out and send it, together with a photocopy of your passport and a cheque for US$5, to the Florida Museum of Natural History. Ask to have a PDF copy of the permit sent to your email address. The museum prefers to send the original to an address in USA, so if you have friends or relatives in America who can be used for this purpose, so much the better.

Within a year of getting the permit, you will need to fill in a form, which you receive along with the permit, telling the museum what you have found and where you found it. On rare occasions, it may ask you to hand over specimens of great scientific value. In addition, there are rules about where you can legally collect fossils even when you have a permit. In particular, private ownership still overrules everything else. (This is America, after all.) So don’t even think of trespassing, as this can have severe consequences. The rules can be read on the homepage mentioned above.

So I did all that, I got my permit and off I went to Florida. The best time to go is from late December to early April when water levels in rivers are low, allowing for wading and sieving (see below). In addition, during these months, daytime temperatures are a pleasant 20 to 25^oC (unlike the severe heat of a summer) and there is no risk being hit by a hurricane.

The best and most interesting fossil locations in Florida are usually rivers. Therefore, turning first to the rivers in the north of the State, I discovered (as I had been warned by local fossil collectors) that these rivers (at least when I could get down to them) are so deep that you have to snorkel and swim to find anything. If I had been with a few people and had rented a canoe to explore some of the smaller creeks, then this might have been possible. But this will have to wait for another time and will have to involve local assistance, but it is hard to organise these sorts of things from Denmark. However, I did find a fossil location by the Santa Fee Rivers with a small outcrop of Ocala Limestone – an Eocene formation – and brought a few blocks with various snails back home to Denmark.

Brownsville, Peace River

Further south was different. I went to a public park outside an extremely small town named Brownsville, a long way from any major city. (The only hotel for miles around is located some 30km just north of another, very small town called Bowling Green.) The Peace River flows through the town and contains a large number of marine and Ice Age land fossils. The marine fossils date from the Miocene and the Pliocene periods and often include sharks (inlcuding Carcharodon megalodon), rays, pufferfish, barracuda, dolphin, dugong (manatee) and whales. Terrestrial fossils, primarily from the Ice Ages (as Florida was submerged during warmer periods), include horse, camel, glyptodont, alligator, bird, turtle, snake, deer and mastodon.

There are two reasons why both marine and land fossils are found in the Peace River. This part of Florida experienced numerous cycles during which it alternated between being dry land and being submerged under the sea. The Peace River is currently cutting and eroding its way down through sedimentary deposits that include those alternating layers marine and land deposits. Therefore, it is quite common to find marine fossils such as shark’s teeth in the same place as terrestrial fossils such as horse’s teeth.

The geologic formation encountered in this region is the Hawthorn Group, Peace River Formation and Bone Valley Member. These represent a period of time from the Miocene (23 to 5.33Ma) to the Pliocene (5.33 to 1.81Ma). In the park at Brownsville, the river is shallow in the winter so you can simply go out in the water and start sieving material. This was what I spent the whole day doing, together with a lot of other fossil collectors – on average, there were some eight to ten other people with me on what was just an ordinary Saturday.

Sharks’ teeth, the biggest one (Megalodon) is about 3cm. Single and worn shark’s teeth are very hard to put a name on. Even nice, sharp teeth can be a problem, but my tentative attempt is as follows: Upper left: a juvenile mako tooth – Isurus sp. Upper middle: a sand shark tooth – Odontaspis sp. Upper right: a bull shark tooth – Charcharhinus sp. Lower left: two teeth from a tiger shark – Galeoverdo sp. Lower middle/left: two teeth from lemon shark – Negaprion sp. Lower middle/right: a partial tooth from a snaggletooth shark – Hemipristis sp. And a more certain one: a partial tooth from a giant white shark – Charcharodon megalodon..

At this site, I found a number of things, but these were definitely not the sorts of things that a keen, amateur collector would normally consider interesting (or maybe even collect, for that matter). However, for me, the fossils I found were new and fascinating.

So what did I find? Mostly, it was small items, less than two centimetres in size. But, of course, this is a good thing if you have to drag your finds half way around the world to get them home. (You can see that I always look at the bright side of things!) Of the fossils I found, most were small shark’s teeth (from several different species, but no big Megalodon teeth other than a small fragment) and assorted pieces of bone, including partial manatee ribs.

In addition, I found quite a lot of bits of stingray teeth and pieces of turtle shell from two or three different species. I also found a piece of alligator scute, a ‘thing’ that a local fossil collector (as I said, there were a lot of people sieving) told me was a alligator coprolite, a small piece of a tooth from what the same local suggested was a ‘duck-billed ray’ (presumably, from the genus Aetobatus) and some pieces of horse teeth (the pattern on one of them indicates that it might not be Equus but from a three-toed horse).

I also found a small part of the sting of a stingray, a very small piece from an elephant tusk (one cubic centimetre in size, but the pattern is unmistakable), a partial bone (probably a femur) from a bird and three small pieces of bone from mammals. The size of one of these piece of bone suggests it came from something the size of a rabbit or hare. The local fossil collector, who had helped me earlier, suggested that the bigger one may be from the canon bone of a deer. The third bit of bone could be anything!

Other fossils from Peace River, the turtle bone is about 4cm. Upper left and right: two partial manatee ribs – Trichechus sp. Lower left: a bone from the flipper of a turtle, presumably a femur, species unknown. Middle left: two partial mammal bones. Middle left: a part of a bone from a bird. Left: a partial osteoderm from the American alligator, Alligator mississippiensis.

I did find two other, slightly more special things. These were a small piece of bone from the flipper of a turtle (possibly, a femur) and a spine from a sea urchin. This had probably been washed out of some older deposit further north and had been washed downstream, maybe, 50 miles south. It is certainly worn enough to have travelled that far.

All in all, I didn’t find that much but, for a first trip to an unknown site in a new country, I didn’t do that badly. However, I should mention that other people had more luck. I saw a couple of almost complete Megalodon teeth, one complete and two broken alligator teeth, and a nice piece of antler from a deer. I was told that even with lots of people coming to this site looking for fossils, good examples continue to be abundant, year after year. Apart from the fossils, I found Florida to be a very pleasant place with good people and interesting nature. All in all, it was very interesting. I will be going back to Florida.