When the letter had been folded, it was tied and then sealed with a clay seal through which the tie would run. For added security, ink marks were then made running across the top of the seal; this is why the names of sender and addressee on letter backs are frequently separated by a large X with its centre missing, that being the point where the seal had been affixed. The ink marks here are clumsy but there seems to be a blank patch as expected. The upper ladder may be the remains of lines that were drawn across the tie on the other side of the spill.
The address translates: From Sarapas and Gaia, and then in the lower panel To Eutyches who distributes wreaths under the gateway of the Serapeum by the great image. Added almost as a postscript at upper right: Give (the letter) to Ammonius who distributes wreaths at the shrine of the god, and he will give it to him.
The Oxyrhynchus Papyri vol.XLIII 3094
First page / Daily Life