U.S. 1847, Carl Schurz Regular Stamp USPS Souvenir Page. First Day of Issue June 3, 1983, Watertown, WI 53094. Scan is an example. Never folded, shipped flat in a sheet protector.
USPS Souvenir Pages or American Commemorative Cancellations are -Official First Day of Issue Cancellations, which are a mint stamp or stamps affixed to an 81/2x101/2 color page, and include technical and historical information about the stamp or stamps and the designer. The pages were issued flat and unfolded.