What Is The Name Of This Cancel?

I found these 2 covers in a box of covers that I recently bought.

I am getting better in understanding specific US descriptions of postmarks. But I am not sure, so I thought let me ask the SCF.

Both covers were send from New York to the same person in Perrysburgh NY.

Both have a numeral 4 cancel.

The stationery piece is from 1871 and the stamped cover from 1876.(The letters are still inside, that is how I know).

My question(s). Is this Numeral four a postmark from Ney York or from Perrysburgh. And what is the correct description? Fancy cancel, numeral cancel, cork cancel? Or some other description?

Thank you for your help.

If you go to www.stampsmarter.com you might find these - there's a bunch of them listed now

Peter

It appears to be duplexed with the New York CDS, so a New York Negative Numeral cork cancel.

Many collectors would call them fancy cancels as well.

Note that there are two different 4s here from different years. That part was carved by hand (as these were) by a clerk or postmaster, or could be bought from commercial suppliers. They wouldn't last forever, so would have to be replaced every so often.

The part with the "4" here was a detachable/separate part, called a killer, meaning it was used to "kill" or prevent reuse of the stamp. So you may see other covers with more stamps, with the dater part struck once but several strikes of the killer.

I would like to thank Peter, littleriverphil and hy-brasil for their reactions.

All a great help and I personally completely missed the thought of calling it a negative cancel.

Back to the box of covers, to see what more I can find.