Many of you are aware of The Marker Monkey. (http://goscf.com/t/3853&SearchTerms=marker+monkey
, etc). Turns out it loves revenue stamps as well as standard postage!
I found this New York stock transfer stamp on the back of an MK&T RR stock certificate. While not a "marker", I think forum folk will agree this "cancel" falls under a MARKER MONKEY!
Perhaps YOU have one to share?