As I was indexing all of my Canadian military mail, I came across this and thought it was quite interesting.
It is a FDC for the 7 cents airmail stamp and it was cancelled with a C.A.P.O. # 1 (Canadian Army Post Office) that was based in St. Johns Sept. 7, 1941 to Jan. 16, 1946.
It is a nice cover and C.A.P.O.#1 serviced "W Force" and this unit is believed to be the 60th L.A.A., BTY, R.C.A. (Light Anti Aircraft Battery, Royal Canadian Army)
Though I cannot confirm this, I would hazzard to guess that the design on the bottom is supposed to be a shadow version of St. Johns on the bottom of the cover (?)
Chimo
Bujutsu
