The  Old Beacon Building

The Mercer Hall was once the Beacon building built in  1906. In addition to newspaper and fine printing operations, the building also housed a book bindery for many years

William Mark O'Beirne (1854-1921) was the proprietor and publisher of the Beacon from 1891 to 1921. He built the original Beacon building on Ontario Street in 1906, mostly to increase its office space. 

In 1923 the Beacon merged with the Herald  which was at 15 Market Place to form the Beacon-Herald. 

In the former newspaper building on Ontario Street now is Mercer Hall, a hotel and restaurant Source: Tim Robertson: