Marty and Jeff's article in the Jul-Sept 2021 LPS Journal just released describes a most interesting cover with a Monrovia Post Office Dept. cancel dated 22 Sept.1911 on the reverse of the cover. Indeed, this seems to be a very scarce cancel. As suggested, Manfred's site has an illustration of this cancel dated 24 May 1912. I sent this to Manfred some time ago and he added it to his excellent site. I saw these two stamps in a common collection offering on eBay along with several other "common" stamps and souvenir sheets. They were far apart set in stock sheets. I hesitate to say I was the successful bidder at $6.52! However, I lost to Henry on my bid on a far better item - it's difficult to compete with your American dollars. The cover shows the Post Office cancel dated 13 Jan.1914. It is shown inverted to better read the cancels. Are there more Monrovia Post Office Dept. cancels out there?