Western Australia 1885-93 Wmk Crown CA 1/2d Green on 1902 'Senator Matheson' cover from Perth to Adelaide

1885-93 Watermark Crown CA 1/2d Green on 1902 on 'Senator Matheson' cover from Perth to Adelaide, tied by 'SHIP MAIL ROOM/PERTH W.A.' duplex with handstruck 'T' in blue and '1' in black, and 1902 Blank at Base 1d Postage Due affixed tied by G.P.O. Adelaide CDS, very fine