This artwork, of the seaman with the outstretched arms connecting Britain with the Continent, was used by the Stoomvaart Maatschappij Zeeland and partners for many years. It appears in various languages and sometimes with variations as to the ports served. Here it is for the "main" Hoek van Holland/Hook of Holland - Vlisslingen/Flushing to Harwich day and night services and shows the numerous onward rail connections that were then possible. It also promotes "cheap returns" to London and other stations in England and Scotland.
The advert appears to have been a page on a pad that has been carefully removed and the blank section possibly was for notes or written information as poster versions of this artwork usually have timetable information here.