You might take a look at "Magic on the Rocks" by Michael Furtman.

Chapter 1 - 3 give you some background about picto's and Chapter 8 focuses on picto's found in the Boundary Waters. 

For those that have interest in this subject, you might also take a look at the Fisher Maps website.  They are now offering a new "Northwoods Pictographs" series (Quetico only at this time) that was developed by a frequenter of this board.  They are full color sheets with detailed information about each picto accompanied by a series of photograph ranging from distant shots of cliff faces (for orientation) to closeups of individual images.  And since they are sold by Fisher, small map segments show a map-based reference to location.

I received a few complimentary copies from the originator of this work.  They are quite nice.

dd

Hi all!  I've never read anything about pictographs, and I'm doing a trip on the Kawishiwi this summer.  I would like to know if there are any good "first reads" to give me a background of knowledge about pictographs.  I take middle school students and want to be somewhat informed when we get to that point of our trip.  Specifically, we will camp near the north end of Insula and day trip east through Alice towards Fishdance where those pictographs are!  Thanks for any info!