Elevation of a Giant Order Portico

Drawn scale, 6 ft to 1 inch (10 ft = 41.5 mm).

The drawing is a view through the structure at upper level, on the centre-line of a bay adjoining the crossing. On the left is a crossing arch drawn in profile and, immediately right, a clerestory window in section, within the upper wall of the nave, the drip moulding of its sill carefully drawn. To the right is the triforium gallery above the aisle, between the clerestory wall and the bastion, and beyond is the upper wall of the bastion, its window reduced in height by the addition of a flap.

When the bastions were extended upwards by a full storey, full-height linking walls and upper barrel vaults were needed between the crossing arches and the bastions, directly above the barrel-vaulted aisles within the crossing square. This half-section looks towards this linking structure and shows, in red chalk and dotted pencil at lower triforium level, an arch at the base of the linking wall between the clerestory and the bastion; above this is a dashed ink line marks the base of the rood beam of the triforium gallery on the outer side of the wall. The shallow triangular section of the roof is drawn faintly in pencil above this, its slope-fitting nearly beneath the drip moulding. The wall rises to a barrel vault at the built level. A segmental-headed window is sketched beneath the vault. Built wider than drawn here, ti looks out across the void between the screen wall and the upper nave and admit lights to the crossing area through the arched openings above the diagonal bays.

The section of the outer screen wall has not been drawn, but the plinth is shown in two stepped courses, separated by a channel. The drawing can be placed after the earliest sequence of designs for the screen walls, where the plinth is in a single course, and later than an incomplete penciled section for triforium gallery where the roof structure is higher up, and the two-step plinth is tentatively sketched. It precedes Edward Pearce's half-section in which the roof beam has been lowered still further and the flying buttress makes its first appearance. It therefore appears to show that Wren developed the design of the upper elevations before he worked in detail on the triforium roofs, cross walls and flying buttresses.

Drawn on the central axis of the lower part of the bastion is a semi-circle in dotted pencil outline: this may represent the profile of a dome intended as a covering before bastion was extended upwards. If so, the drawing shows the south-west bastion, and the slot window in the plinth is to light the staircase, which terminates at the upper entablature.

The bastion window is drawn on a flap which covers an initial design in ink for a larger window extending three courses high and with a pencil-drawn relief panel above. On the back of the flap itself is a pencil study for the ink-drawn window on the front.

The word 'naked' written vertically by Hawksmoor beneath the architrave of the outer wall section, refers to the wall surface of the channeled rustication.