Keystone Stereographic Cards & Viewers - $600 (Leon, Iowa)

Several boxes of stereo views and at least two viewers.
There is at least one box that says "viewer" but is empty.
I believe there are about 80 cards in the Animals I and 2, Tour of the World, about 100, Selected Subjects, about 100, and Scenic America, about 100.
In addition there is an older wooden viewer, with a stack of cards (maybe 40?) One set of cards not in the boxes above is from the San Francisco Fire, very early 1900s.
Boxes look like set of books when placed on shelves.
I make frequent trips to the Des Moines area and can meet with a buyer at some convenient location, for the sale.