bluestone, which is surmounted by a course of splayed blocks of Mount Somers limestone. Above this is the facing of Barrabool Hills sandstone. Two types of limestone, both of New Zealand origin, have been used for the external dressings: Mount Somers limestone for the plinth course, doorjambs and window tracery, and Oamaru limestone for all other dressings. The colonettes, flanking the window and door openings, are of polished Aberdeen (red) granite. The roof of the church is clad in Westmorland slate, with 'tile ridging'. Westmorland slate is of English origin; it has a tendency to be green in colour, in contrast to the blue-coloured slate from Wales. The slates are doubled-nailed with copper nails. The original 'tile ridging' was replaced in 1941. At the crossing of the roof is a flêche, substantially of pressed zinc on timber framing. This is in the form of a polygonal shaft with eight trefoil-arched openings, containing louvred vents, surmounted by a tapering conical spire, clad partly with rounded slate, and partly with flat sheet zinc. The flêche is further embellished with a row of projecting decorative elements at the base of the spire, and a Latin cross, once gilded, at the apex. The Fitzgerald Tower, as it was named in the 1890s, remains incomplete. It was originally to be 162 feet (about fifty metres) tall, to the tip of the spire. The tower, presently consisting of the equivalent of only two storeys, is square in plan, with intersecting buttresses at each corner. The first floor level (approximately in line with the roof of the aisle) is articulated by a course of splayed limestone blocks, and the upper level by an arcaded limestone frieze, consisting of a row of trefoil arches supported on squat columns with cushion capitals. Church interior Main portion of the church The church is planned on the traditional Latin cross form. The total interior length, from east to west, is 175 feet (53.3 metres) long, or, as described in a contemporary source: 'nearly three chains, or three times the width of Bourke Street'. The church is 96 feet (29.2 metres) wide, from transept to transept, or 'being five feet narrower than Elizabeth Street, from shop window to shop window'. The bulk of the east–west portion of the church is 68 feet (20.7 metres) wide, and comprises a nave, flanked by two aisles and three pairs of projecting alcoves, three of which