Fascinating hand made volvelle. The maker started with what appears to be a portion of a Sanson-Moullart map of the Northern Hemisphere (not listed in McLaughlin). The hemisphere has been cut out and mounted on on a larger sheet of paper in the form of a rotating volvelle, with manuscript Roman Numerals around the hemisphere. California is shown as an island. A truly unique item, which judging by the notations at the top of the page was probably part of a larger manuscript work.