Also when they row it after a hard rain is a good time to check back over it.
Also check out a fresh plowed field, with the farmers permission of course. Me and my uncle growing up used to do that in the Panhandle. They were pretty productive for arrow heads, spear points, etc., especially after a good rain. We just used a long stick and when we saw some flint, flipped it over to see what it was. I collected a lot that way and still have most of them.
I've also camped/canoed the Peace River and collected plenty of fossilized bones, and sharks teeth.
If it a wma or any state agency owned land you can not take them or dig for them.
Guy I know is a retired Wildlife Officer...and does that stuff all up around Aucilla. Spends a lot of time on the river, goes to the shows and everything. Man what a collection he has!
My family goes up to the Peace River a couple times a year. It's not really my thing, I go for the fishing, but if you want to try it go to the Peace River Campground in the spring and go upriver from the boat dock, dig where the gravel is and watch out for gators. They find all sorts of things from sharks teeth to glyptodon scutes to three toed horse teeth (yes you read that right).
