These are cool, Robert (I've downloaded all three). Unfortunately, they've been scanned at too low a resolution (or possibly over-optimized in Acrobat) to be readable.

I've noticed this with public library photo archives, of late -- they're about ten years behind the times when it comes to file size thresholds, and unfortunately, that means they'll be rescanning a lot of this stuff when it becomes apparent that their stingy initial space allocations were way too low..!

There are a LOT more on that site, but I got tired of searching after a while. 

At least they're readable.  History of the Clackamas is difficult to locate.  The forgotten forest.