Gastropod? Mollusk? Or?

[Burke_Family]

Our 3rd grader found this on a beach in Coos County, OR. Her first impression is that this is a snail fossil. We’re wondering 1) what is this and 2) if this is an internal mold? There’s also an impression on one side of the matrix that looks like a separate cast. But we’re really not sure… we are having a difficult time visualizing what’s going on here.  When you look closely at the spiral it does appear to have shell in there. We’ve googled a ton and compared pictures of different spiral fossils, but still aren’t sure. Thanks for any info! 

[Oregon1955]

Howdy,

Your 3rd grader is right! She found a gastropod. The steinkern on the side appears to be from the same creature as the more complete section on the other side (1st pic). If it had come from the Astoria formation north of Coos county I'd suggest Psephaea indurata though I believe it is now classified as Fulgoaria induata. I don't know what formation your beach cobble comes from but it's likely older than the Miocene Astoria formation so try looking at Fulgoaria sp. from the Oligocene. So glad your family is investing in your children's scientific curiosity.

Mike 

 

[Burke_Family]

Thanks! This is really helpful information. The pint-sized fossil finder is pleased she’s on the mark. We will research further using the information you gave us. :-)