Any clues on this one?

[CALWilson]

[sixgill pete]

Interesting. There appears to be 2 of the same thing in the rock. However not really sure if it is geologic or fossil. Might be an imprint of something. Good closeup high quality photos of these items, not the entire rock; would be very helpful in determining if they are fossil or geologic.

[Fossildude19]

I think the depressions were formed by water flowing over it, and eventually creating a kettle, or pot hole, where rocks and sand got caught in an eddy, and were swirled around by the water, creating the rounded depressions.

Alternatively, it could be the worn depression of where a concretion/concretions once rested. 

Either way, I believe this is a naturally occuring phenomena. 

Regards,

[Kane]

Tim beat me to it. Most likely not a fossil, but distantly possible that this could have been the impression of some kind of shell. You may want to include something to indicate the scale of the object to help with identification.  

[CALWilson]

Thanks!  It's about one inch long.