P.D. Ayer & Co. Series 4 postcards, as enumerated by Mike Smith in his latest book, The Canadian Patriotic & Heraldic Postcard Handbook 1897–1945, illustrate a coat of arms of Canada over a beaver and two branches of maple leaves.
Typical Card Back I
AYR4-004
AYR4-009
AYR4-014
AYR4-018
AYR4-020
