Shells

While driving to work one morning I distractedly heard the voice on the radio saying: 
There's a tiny island called Yap out in the Pacific Ocean. Economists love it because it helps answer this really basic question: What is money?
It was the beginning of a story from NPR Morning Edition and as I kept driving I thought: I bet it involves some kind of shell.
Well, I was wrong and that story did not involve shells at all. In fact, historic Yapese people used imported limestone disks, some so big they can be hardly moved - the equivalent of a safe I guess - as their main form of currency for their trades and exchanges.

PAHMA curates a rather large archaeological collection from Oceania mostly due to the sizable assemblages that were excavated by Edward W. Gifford between 1947 and 1956. He was, at that time, director of the museum after he succeeded Alfred L. Kroeber in 1947.
These are large shell trumpets from Yap where Gifford and his wife had their last archaeological expedition in early 1956. During this project they found seven of these trumpets on the island, two were from archaeological context; the rest like those featured here, on the surface.

Shell disks and pendants were, however, also used as currency perhaps unsurprisingly as "small change". Somehow I knew that my stereotypical expectation couldn't be completely off target.

Hearst Museum # 11-36962 and 11-36964
Shell trumpets (Charonia tritonis)
Micronesia; Caroline Islands; Yap
Collected by Edward W. Gifford, March 1956