The best info is for free at your local USGS, they might still have some publications for sale. I was very lucky years ago I visited the usgs store in Anc. and discovered many old pubs were for sale, I bought all I could find that interested me.. Case in point. I was looking for a spot on a river called Deadmans riffle.l Modern maps, ha, no luck there. In one of these old pubs I pulled out the old map in the flyleaf started looking at it and almost dropped the map. The first thing I saw was Deadmans riffle and a score of other places these stampeders had found gold... You want to pay particular interest in how the old time Geologists used terms to describe the type of gold being found at placers they visited... Nuggety, Shot, Heavy, coarse, etc this will turn you on to places a detector might find some nice pieces. Good luck good hunting and never give up..Geo
