The cornucopias, as the priests and philosophers and gold are supposed to be infinite supply, so I guess you would replace them with something else.
That said, I agree with Jon's comment: 17 TURNS ????
Don't know about cornucopias, but Bruno has a different idea about the priests (Cut from Zeus in 2p):
Bruno des Montagnes wrote:
Now, for ironjames, if you run out of priest cards, you just don't get one more priest when choosing zeus ! This situation is theorically possible, but it never happened to me