This is a fossil dugong (Metaxytherium Floridanum) rib section that was recovered from the Peace River in the Bone Valley formation of Florida (Miocene Period, approx. 7-14 million years old). It is covered in deep, round holes that are the result of clams boring into the bone millions of years ago before it fossilized, leaving behind their bore holes as their only remnant. This piece measures almost 3 inches in length and is very heavy.
Refer to the photo. The black centimeter cube is shown for scale and is not included. You are purchasing the specimen shown.