Canada 1851 6d Consort Cross-Border Folded Cover Montreal to Philadelphia USA

Folded cover, franked with four-margin 6d slate violet Consort on laid paper, cancelled with centrally-struck seven-ring target cancel, neat Montreal OC 16 1851 double split-ring, matched red PAID and Canada arc exchange office marking, circular "10" rate handstamp, to Philadelphia, a beautiful and scarce cover with tremendous eye-appeal, destined for an advanced collection of the highest quality; ex-Carrington, Cantor, with 2011 Greene Foundation certificate.