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Sunday, November 27, 2016

Help with a mystery object?

Okay, this one is a true mystery.  We found this object while walking Dillon Beach on 25 November 2016:


Our best guess right now is that it's the periostracum (outer covering) from a large bivalve.  (It measured ~6.5 cm long by ~5 cm wide.) 

However, the material and its transparency seem different than other bivalve coverings that we've seen, so we're open to any other thoughts or suggestions.  The inner surface appeared to have a chalky white residue (perhaps from the middle shell layer of a clam?).

And even if it is the outer covering of a clam, we are uncertain about which species it's from.

Here's another view, this time from the side:


Let me know if you have any ideas about its identity.  I'm still working on it, but it would great to solve this mystery!

ADDENDUM (28 November 2016): Several people have suggested this could be the operculum ("trap-door") of a large snail, e.g., a whelk.  That's a strong possibility, and at this time I think I'm leaning that way.

ADDENDUM (1 December 2016): For the identity of this mystery object, see the post on 28 November 2016.

2 comments:

Anonymous said...

Looks like a bleached out Velella.

https://youtu.be/ZJGO_bSsR3w

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwi8wt3G5czQAhVC8mMKHUJtAqwQjRwIBw&url=http%3A%2F%2Fwww.cnn.com%2F2014%2F08%2F19%2Fus%2Fcalifornia-sea-creatures%2F&bvm=bv.139782543,d.cGw&psig=AFQjCNEI5_-9rZ-MVfnqtM4DovfT9noI7g&ust=1480468551581166

Fun stuff. John W

Jackie Sones said...

Hi, John!

Eric mentioned the similarity to Velella also, at least when the "mystery object" was dried out. See the next post from 28 November 2016 for the answer!

Jackie