Brass lensboard, circa 1880: What camera?

Recently aquired a lens from about 1880 and it came on a peculiar lensboard. Wondering what camera that may have been used on.

The lens is a R. Morrison Wide Angle View Lens that is marked for 6 1/2 x 8 1/2 format. That would be about 165mm focal length. The odd part is the lensboard to whch it was attached: heavy brass, 4x4 inches, and with 2 different screwed fittings. One of hte fittings is the lens flange and the other screw fitting is another flange between the lens flange and the lensboard.

But what camera could that lensboard be from?

Looks very early and European in origin.

Maybe @Ian Grant will have some ideas...

American, actually. Morrison was a New Yorker.