Silver Spanish Coin?

[Panama Brett]

I found This while Md at the Beach this is what it looks like after I cleaned it up. I know the coin is Fubared however Maybe someone knows what it is.

 

[Mackaydon]

Welcome to Treasure Net !!
Can you post a pic of the other side?
I have no clue with the above pic.
What is it's diameter in mm?
Don.......

 

[Panama Brett]

This is the only side thats some what readable it looks like a skull some what I tryed the pencil and paper method, however it is real worn I could not make out anything I will take some measurements and post soon..

 

[Panama Brett]

Thanks