Two Fossil Ammonites (Jeletzkytes) - South Dakota

This is a 2.7" wide section of rock that contains two Jeletzkytes sp. ammonite fossils, collected from the Fox Hills Formation of South Dakota. The smallest of the two ammonites was removed from the rock it was found in, prepped and then remounted to this rock.

One edge of the rock has been cut flat to facilitate aesthetic presentation of the ammonites without the need for a display stand.

These 70 million year old ammonites lived when South Dakota was a shallow inland sea. They were found preserved in concretions when split open. They then had to be hand-prepared to remove the hard rock surrounding them from their shells, a very time consuming task.

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
Jeletzkytes sp.
LOCATION
North Central, South Dakota
FORMATION
Fox Hills Formation
SIZE
Ammonites: .9" & 1.1", Rock: 2.7 x 1.6"
ITEM
#189342
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