The brick building on the right is the post office, built beginning in 1901. It was built as a three story building but lost its top story in the fire of 1929 which wiped out the entire block except the Bank of Montreal, on the far end of the block, and severely damaged the post office. The damage to the upper floor was sufficient that what remained was torn down and a new roof built on the second story.
The Bank of Montreal is the beige colored building further away on the right. The rest of the block on the right has changed since the photo was taken, as has almost all of the block on the left.