[meteorite-list] Secret BLM maps ?

[Thomas]

Last week I was walking along a dry lake bed and looked up to see the 
inevitable white truck parked next to mine. I walked back and had a nice 
talk with a BLM officer. He was concerned that we were picking up 
artifacts, which we were not. My wife mentioned that we were going to 
look for some petroglyphs and asked him about the roads in that area. 
"No Mam", he says. "We can't tell you anything about locations. In fact 
there are many more petroglyphs and over a hundred caves that are not on 
your maps and we can't tell you anything about."

Which makes me think that these locations must be a matter of record 
somewhere. Does the BLM have secret maps not available to the public?

Thomas M

Petroglyph pictures if anyone's interested : 
http://www.photoblog.com/GreyDX/