Mystery Fossils

Data: Hello,
Sorry to bother you, but you were the person we found online that looked like they may be able to help us or at least point us in the right direction.

We have lived in California for 19 years and visit the coast at least 2-3 times a year. This year we ran across some fossils that we have never seen before. Could you tell us anything about them?

Mainly we are interested to know if they are common, & how old they are?

Thanks in advance,

Steven & family
Sacramento, Ca

Send Ideas to: Steve





  • The specimens in your photos represent blocks of lithified sandstone/siltstone containing dense concentrations of fossil mollusk shells. I can recognize shells of scallops, clams, and snails. However, because only portions of the shells are exposed it is difficult to be give a more precise identification. The scallop shell does suggest a late Miocene or early Pliocene age and I suspect the sandstone/siltstone blocks were collected in the Santa Cruz area and are derived from sea cliff exposures of the Purisima Formation.
    I hope this information is helpful.
    Regards, ...Tom D.


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