Today we are going to fully identify a US postal Stationery cut square, specifically a U1 (the very first listing in the Stamped Envelopes and Wrappers section of the Scott Catalog).
There are 12 varieties that depend on the detailed characteristics of the Head and the Lettering. These varieties are not listed by different minor catalog numbers in Scott, but are studied by specialists that recognize the subtle differences that exist due to variability in the production process in the mid 1800s and that different engravers were employed for the task. These combinations of Head and Lettering styles are called Working Dies.
For details on this identification data, see pages 164-170 of Catalog of the 19th Century Stamped Envelopes and Wrappers of the United States, Allen Mintz, Editor, published in 2001, by United Postal Stationery Society, Norfolk, VA, ISBN Number 0-9670045. Note that there is newer version of this book available from the same publisher but with a different Editor.
Note the diagonally laid paper used in the early US postal stationery.
Which variety is it?
Clue #1: The E of Cents is clearly lower than the N next to it, so that narrows it down to Types 2, 4, 6, 7, 8, 9, 10.
Type 2 eliminated as RE is not wide at top.
Type 4 eliminated as the Head II does not have the observed curved sideburn.
Type 9 eliminated as CENTS is not near the inner oval line
Type 10 eliminated as THREE is not high in the label.
That leaves Types 5, 6 or 7 as good candidates because this example displays at least one of the official characteristics of these types to some extent.
Clue #2: Severe misalignment of the E lower than the N. See photo above, the E is slightly slanted down to the right.
Clue#3: Curved lock of hair at the ear has a circular bump below it.