Mid-60s pic reveals mysterious downtown structure

The Navy League property in 1947

   See that little image in the inset on the bottom right? What the heck is that little thing behind the Seville Theatre?
  The apartment building behind the Seville on Closse burned down around 1977 or 78 but this little thing had already disappeared by then.
   I remember the night that apartment building burned down because my father lived next door and was irked because I didn't inquire whether he was alright. I was about 15 at the time.
   I've described the story of how my father demolished the old Navy League building - putting Montreal's local theatre industry in a bad way by doing so - in order to build a parking lot for motorists attending events at the adjacent Forum.
    And I've also noted somewhere else about his habit of expanding his parking lot onto adjacent properties such as laneways and empty lots in order to improve his profits.
    But I don't know what this particular weird little structure was or when it disappeared. If anybody knows, give me a heads up.