This is a lot of fossilized vertebrae (2) that were collected from the famous Bone Valley formation and Peace River in southern Florida. This region is well-known for it's rich deposits of Miocene, Pliocene, and Pleistocene period fossils. The oldest pieces are upwards to 23 million years old and the more recent pieces are about 11,000+ years old. Both of these specimens are quite river-worn and incomplete. Someone with more expertise might be able to positively identify the species and ages of these pieces.
Refer to the photo. The black centimeter cube is shown for scale and is not included. You are purchasing both of the specimens shown.