I've never been to Butte County in all the time I've live in Cali. I'm guessing he was searching with his detector in a drier area. It wasn't in a river, I'm really curious where he found it. Too bad you didn't luck out and find this baby when you lived there!
Puerto Rico was cleaned out of almost all it's gold by the Spanish. I looked in a couple areas when I was there but found nothing at all.
!BBH