4.5" Fossil Ammonite (Rhaeboceras) - South Dakota

This is a 4.5" ammonite (Rhaeboceras) from the Fox Hills Formation of South Dakota. This amazing specimen has beautiful shell on one side that is iridescent and shows areas of inner shell sutures. On the reverse side much of the shell is missing, giving a view of the inner structures of the shell. A striking display.

Ammonites were predatory cephalopod mollusks that resembled squids with spiral shells. They are more closely related to living octopuses, though their shells resemble that of nautilus species. True ammonites appeared in the fossil record about 240 million years ago during the Triassic Period. The last lineages disappeared 65 million years ago at the end of the Cretaceous.

What an ammonite would have looked like while alive.
What an ammonite would have looked like while alive.
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DETAILS
SPECIES
Rhaeboceras halli
LOCATION
South Dakota
FORMATION
Fox Hills Formation
SIZE
4.5"
ITEM
#115161
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