The Library and Archives of Canada (LAC) is in the process of digitizing hundreds of Canadian city directories and placing them online in a free, searchable database, complete with images.
The "Canadian Directories: Who Was Where" project has started with Halifax, Nova Scotia, and there are dozens of directories online for Halifax ranging from 1880-1897. It's really simple to do a surname search and then use the pull-down menu to select a specific year, or select all.
At any rate, take a look and see what you can find. Unlike U.S. directories, however, Canadian directories didn't really denote black folks, so it may be more difficult to differentiate your ancestor, especially if he/she had a common name.
All the best.
- Lisa B. Lee, PLCGS
Oakland, CA