help identify, marine fossil

[unclemac]

The material is agate, the hole through it has some of the original shell still attached to it. It comes from a beach where I have found other agate fossils of clams, snails, twigs etc. that date to about 80 million years ago....but for the life of me I just can't figure out what it is, (other than the obvious).

 

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[Age_old]

To me, it just looks like a combination of several shall casts. I can see some kind of bivalve and the hole is where a turritella was; the shell left a cast and then broke away.

 

[unclemac]

Here are some better pictures. This is all one organism and not a combination. The hole does not taper like a turritella would. There are other bits of shell in other spots on the fossil.

 

[Age_old]

Hmm.., that's a tough one. I'm stumped! Sorry

 

[GatorBoy]

Would a sea cucumber leave a fossil. I don't know the scientific name.

 

[unclemac]

I'm not thinking that sea-cucumbers have any shell parts to them...and this most certainly does.

 

[unclemac]

bingo! gotta love those museum curators...(excerpt from an email I received)

[FONT=&quot]You have found a wonderful fossil! This is a fossil nautiloid – a squid type animal with a shell. See this website for more information Nautiloids: The First Cephalopods Near the bottom of this web page (long page!) is a photo of Eutrephosorus, which is very similar to the one you have. [/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]The nautiloids from Washington are younger than that one: 35-25 million years old and they were the last nautilioids in the northern Pacific. Now living Nautilus are found only in the southwestern Pacific (there is a photo of one in this website). Your fossil is agatized (silica minerals have replaced the calcium carbonate of the original shell) are very resistant to weathering and are washed down rivers from the foot hills of the Olympic Mountains all the way to the beaches. [/FONT]

 

[BeachComber7]

wow! That's really old!!!