From todays estate auction purchase. One of the binders was labelled 'Fancy Cancel's'. Of course, most of them weren't. But I was able to glean these out of the batch.
Nice 'web' on the #63 Franklin, top left corner. The pair of Washingtons on the top row with what looks like an 8 (?) pointed star has a C grill. The other pair on piece (corner of a mourning cover) is also grilled, but can't tell which. The first Washington on row 2 has, I believe, a beautiful purple New York Foreign Mail cancel. The cross on Jackson in the middle of the same row is also an NYFM, circa 1870 - 1879.
You're talking about the most right hand stamp on the row second from the bottom, correct? I don't know what a fancy cancel expert would call it (I'm only an enthusiast) but to me it's reminiscent of something you might see on a cheque (check to my US friends). So perhaps some sort of revenue cancel? Let see what the experts do say.