VERY FINE APPEARANCE. A RARE AND BEAUTIFUL EXAMPLE OF THE DESIRABLE BINGHAMTON HERRINGBONE CANCEL
Fancy "killer" cancels are extremely rare in the 1847-51 period. The term "killer" to describe the cancel was actually used by New York Postmaster Robert H. Morris. Although fancy rate markings from the pre-stamp era were used to cancel 1847 stamps, fancy cancels created for the specific purpose of "killing" stamps did not become popular until the 1850's.
From the Sarah Roseboom correspondence. Ex Rohloff.