Two big commemoration stamps one for the 100th Anniversary of Iowa Statehood and the other the  Annapolis Tercentenary.  

A U.S. First Day Cover, or FDC, is an envelope or sometimes a post card bearing a stamp cancelled on the date the stamp was first available for postal use.  In the United States, stamps are traditionally placed on sale at a site designated as the official First Day post office, where there is usually a ceremony dedicating the new stamp. The stamp or stamps then go on general nationwide sale the following day.

First Day Cover collecting first became popular in the 1920s, when the post office began to issue commemorative stamps more frequently. In the 1920s and early 1930s First Day Covers were postmarked with everyday working postmarks. This can make it challenging to identify some of the earlier covers if you don't know the dates of issue. The first official first day postmark with the familiar words "First Day of Issue" between bars was used for the Ordinance of 1787 commemorative in 1937. In the late 1950s to the early 1960s, there was often a small illustration included in the postmark below the city name and date.  In more recent years, first day postmarks have usually been unique graphics related to the stamp's subject, often in color.