Here is one of my covers that is on the PhilaMercury census. As someone once explained to me that the single stamp was cancelled by the carrier, or the fee from post office to door?
The Philamercury cover shows a carrier fee for service to the post office. The delivery fee from the post office could not be prepaid with stamps except on local letters.
The hand stamp (barred oval) looks identical.
The Philamercury cover from Philadelphia has a obliterator with a rim, the cover in the original post in this thread is from New York and has a rimless obliterator.