Lot
726 
Stemmed Leaf, clear strike ties 1869 6¢ ultramarine (115) on buff cover to London, England, red "New York Apr 23" exchange cds, carried as endorsed by the NGL Line Union that departed New York on Apr. 23rd and arrived at Southampton May 4th 1870, red London (5.4) arrival cds; no flap and couple tiny edge tears at top, still Very Fine. Weiss No. RE-LF5 Estimate $300 - 400.
This new cancel type is documented in Dan Richard's NYFM update article, U.S. Cancellation Club News, volume 29 on page 27.