Spirally shell fossils

[RCD]

Would love to know the species of these spirally shell fossils. I think they are from the late Miocene but not sure. I'm also curious if the oblong rock intrusions in the first pic might be fossils as well? The location is the East Bay Hills in between the San Francisco Bay area and the Central Valley of California, USA. Thanks!!!

[Lone Hunter]

Mostly cross sections of gastropods is what I see.

[Rockwood]

55 minutes ago, RCD said:

. I'm also curious if the oblong rock intrusions in the first pic might be fossils as well?

It's possible that they are trace fossils, but I don't see any definite indication of it.

[Ludwigia]

The snails could belong to the genus Turritella, but you'd have to research the formation's faunal assembly in order to find out for sure. Only an expert on this fauna could suggest a species to you.

[DPS Ammonite]

We are going to need a formation or layer of rock to determine if turritella occur. I remember seeing a nice layer of turritella south of Mt. Diablo Mountain in the State Park.

 

https://www.geocaching.com/geocache/GC1KH9Q_turritella-snail-bed?guid=5ae3b488-49af-4c67-9382-48b4c989243b

[RCD]

11 hours ago, DPS Ammonite said:

We are going to need a formation or layer of rock to determine if turritella occur. I remember seeing a nice layer of turritella south of Mt. Diablo Mountain in the State Park.

 

https://www.geocaching.com/geocache/GC1KH9Q_turritella-snail-bed?guid=5ae3b488-49af-4c67-9382-48b4c989243b

Thanks for that link. The location is close to Mt. Diablo so good chance it is also Turritella. Thanks again!