no it is skeleton pieces of tiny sea creatures.
i pokes out
Skeletons:All animals, including humans have skeletons. Humans have an internal skeleton. This means that our bones is on the inside of us. When an animal has an external skeleton it means that their skeleton is on the outside. These animals who have an external skeleton have what we commonly call shells. These shells are their skeleton which keeps their insides together. If you think of one of those big crabs and how there is a shell on the outside of them (not sea shells) this is their skeleton which is an external skeleton.
Lime stone is a sedimentary rock formed by the skeleton remains of ancient minute sea creatures.
Alot of sea creatures do not need the strong skeleton to support their weight. But we have barely explored any of the actual deep sea, so who knows what might be found.
External, meaning outside. Thus, Outside(External) Skeleton.
Near coral
It is endoskeleton. Seahorses have an interior skeleton.
The exoskeleton would mean outside the skeleton.
outside
Some sea creatures have ansetors of dinosaurs
Ants have an exo-skeleton - i.e. it is outside their body.