The United States Stamp Society (USSS) has an online glossary of philatelic terms (see www.usstamps.org). Their definition of a souvenir sheet is, ďa small sheet of one or more stamps, valid for postage, usually issued in conjunction with a philatelic exposition.Ē If you ask any stamp collector, this closely resembles their idea of what a souvenir sheet is.

Let me set the trap for you.

Look at Scott #1686-89. These were the four murals for the American Bicentennial issued during Interphil í76, the international stamp show hosted in Philadelphia. The Scott catalog lists them as souvenir sheets. This sounds right on the mark.

Scott #2940 is also listed as a souvenir sheet. It shows four stamps with Norman Rockwell paintings. It was not issued in conjunction with a philatelic exhibition. Yet the catalog editors listed it as a souvenir sheet. Maybe they were stretching the definition a little bit.

Scott #3136 is a mural design of Dinosaurs, similar to the mural design used for Scott #1686-89. Scott #3136 was not issued during a philatelic exhibition and isnít listed as a souvenir sheet. OK, that makes sense. But then why was #2940 listed as a souvenir sheet?

Scott #3649 is the Masters of American Photography. This issue is not listed as a souvenir sheet. Ignore the fact that this pane has 20 different stamps and Scott #2940 only has four stamps. Otherwise, arenít these two issues very similar? Itís the same layout Ė a block of stamps on the left with an illustration on the right side. Why is #2940 listed as a souvenir sheet and #3649 is not?

It canít be an issue with the size. Scott #1686-89 are just as big as #3649. It canít be that #3649 is too big to be called a souvenir sheet.

I could go on with more issues. But Iíve made my point. The Scott catalog listings are inconsistent with what constitutes a souvenir sheet and what is not. What do you think?