Melbourne's site was largely determined by 'The Falls' a rock ledge on
the Yarra which separated the brackish tidal river from fresh water.

The Falls were roughly at the end of Queen St. The ledge was removed to
improve navigation at the cost of available fresh water, but by that
time the Yarra was probably pretty polluted anyway by adjacent settlement.

A bridge was built across the Yarra at this point and of course was
called the Falls Bridge.

The pic attached shows the final state of the old bridge - re-aligned
for the building of Queens Bridge.
http://tdu.to/FallsBridge-from-QueenSt.jpg

Centre right is the foundation of the new bridge, which connects at
Market St and carried cable trams to Port Melbourne and South
Melbourne. It now carries electric trams on route 55.
The hoardings show the name of the contractor - David Munro and Co.

At bottom left a new cable tram is visible. Queens Bridge opened in 1890.
That puts the photo between late 1885 and early 1889.

A steam hauled passenger train is visible on its way to either Port
Melbourne or St Kilda and work is in progress to widen the rail bridge
from Flinders St to the junction of the two suburban lines to 4 tracks.

Running across the centre of the pic is the ground level railway line
that allowed transfer of goods wagons between Flinders St station and
Spencer St station before the viaduct was built.

Mal Rowe - impressed by the South Melbourne Town Hall which dominates
the horizon in this scene