Possible Fossils found in Creek bed

[Joeyfredrick]

In my search for arrow heads I found these items which appear to be shell fossils. Are such finds are common in creek beds?

Thanks!

 

[bone2stone]

Graphia a species of oystera.

 

[old digger]

Those are what we (I) call Devils' toenails. Can find them by the thousands around here.