If the sponge broke down but the salt remained and held its shape, we would call that a permineralized fossil of the sponge. In the Kits: #4: Dinosaur bone, # 6: Petrified wood Compression - These ...

These fossils, preserved through carbonaceous compression or phosphatization, revealed elongate structures along the ventral side of these early organisms. Dr. Deng Wang, one of the lead researche ...