Fossil Living Chamber


Staff member
Moderator (Staff)
Nov 19, 2002
somewhere under the desert sky
This is the best I could do last weekend. Just the mud infill of the body chamber of a large endocerid, would have been about 4 to 5 feet long I guesstimate. A small peice of the endocones is visible in the first photo (upper right corner), with some mud filling the siphuncle at the end of the body chamber producing the nob. And an end view showing the shape of the shell and location of the siphuncle.


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Sorry Kevin, maybe I am being stupid but I can't see the siphuncle. Is it centrally placed?

Great find.
Here are some smaller examples with a few of the chambers preserved. The first pic shows the siphuncle filled to the tip of the hollow of the last endocone.


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Here are two casts of body chamber and siphuncle found in shale over the weekend. They are both showing the bottom side, hence the small trilobite mold in the upper pic is a mold of the top of the trilobites shell. There is also a graptolite laying along side the siphuncle in the top pic. Also in the top pic you can see a ghost of the phragmocone and chambers that dissolved probably before the surrounding shale turned to stone.


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Here is an internal mold of the body chamber and siphuncle inside an external mold of the shell. All trace of the shell material has dissolved leaving the internal mold and a hollow where the gas filled chambers and the shell material used to be. The shell in this example probably dissolved after the surrounding mud had turned to stone, so the hollow was preserved.


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A few other small fossils found this weekend. A small Edriasteroid and a crinoid with the calyx. All Early Ordovician, Floian Stage, Zone I (Ibexian Series, Blackhillsian Stage in NA usage)


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They all were found in the informal Calathium Calcisiltite Member of the Fillmore Formation, in the Ibex region of western Utah. Of course it is a secret spot and if I told you exactly where it was I would have to make a call and have something done about it :wink:

By the way, they were not collected, just photographed in the field and marked with a GPS.
Congratulations Kevin, stunning finds. Might be a little far for me to go and have a look in your 'secret location' though! Any idea as to the species?
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