Stereoview which shows William Henry Jackson outside his photographic dark tent with the materials needed to create wet plate photograph

This stereoview was taken by Arundel Hull who accompanied Jackson. The Union Pacific Railroad contract was Jackson's first big break in photography. On the back it says in in ink 75 photographer in the mountains. There is some staining. Might be the first image of Jackson on a stereoview. The Scotts Bluff National Monument has tis image.