If you come across a set of shark teeth at the lake, don't worry...there really aren't any sharks living in our man-made fresh water lake that has no direct access to the ocean! Since we used to be under water millions of years ago, Lake Texoma is a great place to find fossils of sea creatures that no longer roam our planet.
In particular, Ammonites are plentiful here. An ammonite was related to squids and octupus, but they had a round shell. They lived on earth between the Cretaceous Perios and the Devonian Period and became extinct around the same time that dinosaurs disappeared. In case you're doing the math, they lived here between 66 million - 419 million years ago.