Do you want to report "How can an American get a document notarized from Jamaica?"
Actually, you don’t want a JP if you’re trying to notarize an American legal document. JPs are for documents within the jurisdiction and NPs are for certifying documents that can be used overseas (or within)
What do you consider those appointed under The Notaries Public Act, which appears in every commonwealth jurisdiction to be?
Do you consider the duties “to authenticate contracts, acknowledge deeds, take affidavits, protest bills of exchange, and take depositions” different from notarizing them?
Each parish has a few JPs (Justice of the Peace) in each parish. Ask around and someone will be able to refer you. In many cases the JPs will only sign for people they know or know of. It’s different than in the states.
If you need a US documents notarized and it is allowed, try using an online notary service in your state. There are a few options out there and they usually run $25-35 per notary stamp and a few extra dollars per page.