8.6" Wide Fossil Ammonite Cluster - South Dakota

 
 
 
This is a fossil ammonite cluster from the Fox Hills Formation of South Dakota. It's been wonderfully prepared on the hard concretion it was found in. The largest ammonite is a 3.6" Jeletzkytes nebrascensis and the total width of this cluster is 8.6". There are a number of other complete ammonites in this rock including a Hoploscaphites nicolletii and multiple Scaphites ammonites, along with fragments of shells still partially concealed in the stone.

The Hoploscaphites nicolletii appears to have been removed from the rock, cleaned and remounted, though it is still in the exact location it was found.



Ammonites were predatory mollusks that resembled a squid with a shell. These cephalopods had eyes, tentacles, and spiral shells. They are more closely related to a living octopus, though the shells resemble that of a nautilus. Ammonites appeared in the fossil record about 240 million years ago and they barely survived several major extinction events. The last lineages disappeared 65 million years ago at the end of the Cretaceous.

FOR SALE
$595
DETAILS
SPECIES
Jeletzkytes nebrascensis, Hoploscaphites nicolletii & Scaphites sp.
LOCATION
South Dakota
FORMATION
Fox Hills Formation
SIZE
Largest ammonite 3.6" wide (J. nebrascensis). Entire specimen 8.6 x 6.5"
ITEM
#137271
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