Tower City, Pennsylvania. $10 1902 Date Back. Fr. 616. The Tower City NB. Charter #6117. PMG Fine 12.While at first glance this Third Charter $10 Plain Back appears to be a rare but rather well traveled Pennsylvania note (which is accurate) there is more to the story here. This note displays an incredibly low Treasury Number, K48, at top right. It is the lowest such Treasury Number any of us at Stacks Bowers have ever encountered. Certainly an item of significance for any true National Currency specialist. PMG comments "Seal, Charter, & Serial Numbers Redrawn" on the back of the holder.