I should have looked a little further....
Here are some of the details about the design and the materials they chose.
The design of Ireland Park needed to be in harmony with the powerful emotive energy evident in the sculptures situated in the park, created by Irish artist Rowan Gillespie. The massive, craggy, sculptural rock-face of black Kilkenny limestone was obviously the right material to fill this need. A technical approach was devised to make smaller pieces of stone convey the feeling of massive rock and generate the effect of size, scale, texture and emotional energy. 675 names of famine immigrants, who died in Toronto in 1847, are located in the openings cut into the rock, similar to the fossils in the stone, where they can be similarly discovered. The stone material greatly influenced the design; the light-grey sawn faces of the Kilkenny limestone provide an ideal surface for the inscription of the Famine immigrants' names, just as the roughness of the stone simultaneously evokes the battered bow of a ship, as well as the shoreline of the west of Ireland, the departure point for many emigrants in Ireland.
The stone work has set new standards in technical achievement. Without extensive structural engineering, the gravity-defying sculptural qualities of the stone columns could not have been executed. The structure which is referred to as the ‘memory wall’ is a combination of reinforced concrete and stone.