Page "Cancellation (mail)" Paragraph 34

In the United States, official pictorial cancellations are almost invariably applied at special " stations ", i. e., post offices existing only for a limited time, usually one day, at special events, although there are frequently other pictorial cancellations that are not officially described as such — they are among what are called special cancellations and are special die-hubs added to machine cancels, which usually contain merely a slogan but sometimes contain a picture.