This is: the full souvenir sheet of 15 stamps (Scott 3136) issued on May 1, 1997, titled "The World Of Dinosaurs." It is mounted on an envelope that measures 9 inches by 11.5 inches, and all 15 stamps are cancelled with the First Day of Issue cancel from Grand Junction, CO on May 1, 1997. The envelope is cacheted by Artmaster.

See the scan for details.