Canada CL13

1926 (June) Patricia Airways and Exploration Co. Ltd. Airplane & Frame Cyanotype "Van Dyke" proofs in blue on wove paper. Blocks of four taken from the respective unique panes of eight, one showing frame and wording "Curtiss Lark" and on the other, the airplane and date only, Very Fine and rare (Unitrade CL13 proofs; unlisted)