A third task was the investigation of suitable stone types and sources for the proposed building. The demolished remains of a local stone bridge, the Fitzroy Bridge, which once spanned the Wollondilly River east of Goulburn were available. This stone, though plentiful in quantity and though from the same quarry source, was not adequate in quantity or dimension to fulfil the requirements for the proposed tower and spire. A search for the original quarry was begun and it was eventually found just east of a small town called Marulan, some 30 kilometres east of Goulburn. The quarry, which had not been disturbed for almost a hundred years, was an archaeological site, but not suited to the extraction of stone in the quantities required by the project. The costs of re-opening the quarry were outside the resources of the project. Other sources were investigated and eventually an operational quarry north of Sydney was selected for the supply of stone to the project. This quarry, Central Coast Quarries, had the ability to provide the quantities of stone work required as well as the capacity to produce profiled stone. The Fitzroy Bridge stone was used for the "rock faced: body work, being appropriately sized for that use. When the project commenced other sources became known, particularly another source of (original) Marulan stone left unused at another Goulburn church.
