Inveraray Castle Estate, Carloonan Bridge

This bridge carries an estate road across the River Aray, 270m N of Carloonan Falls and Mill (No. 230), at a point where the river narrows to provide a firm rock-abutment at each side. It was built in 1755-7 by the Argyll Estate mason, William Douglas, who had considerable experience of bridge-building for the Commissioners of Supply.

The bridge is built of local granite rubble, with arch-voussoirs of diagonally-tooled chlorite-schist, and schist-rubble in the arch-soffit. The parapet has a rounded granite-coping, although schist from St Catherines was included in the original estimate (infra). The segmental arch is 12.2m in span and the overall length of 25m includes curving approach-walls which were altered in the 1780s. The roadway is 4m in width within parapet-walls 0.4m thick.

Douglas produced an estimate in 1751 for 'the Bridge above the milln', which specified a 'hewen border (?voussoirs) and copeing of St Cathrin's stone', with other stone and limestone coming from 'the milln quarry' (No.229). Because of other contracts, work was delayed until1755, and completed two years later (en.1). In 1783 the 5th Duke of Argyll gave instructions that 'both the ends of the Bridge are to be made very much Widend so that a Carriage with four horses may pass every way without the least difficulty. This to be done in the manner directed to you by Mr Mylne’. The execution of this work may be recorded in RobertMylne's diary for September 1785, when he visited 'Cascade Bridge' (en.2).

RCAHMS 1992, visited May 1988