Drumagully Bridge

The Department's description

Exterior description and setting

An arched masonry bridge carrying a minor road over a stream at the north end of Downhill Forest. Except for its voussoirs, it is of random rubble basalt construction throughout.
The arch springs directly from the rocky bed of the river and is of semicircular profile. Its voussoirs are of dressed sandstone with alternating stones slightly made longer and having ‘vermiculated’ faces; there are also similarly embellished triple keystones.
The base of the arch has been concreted to prevent scouring. Both faces of the bridge curve outwards on either side of the arch to form square-cut piers which rise to form pedestrian refuges at road level. Each curved section contains a shallow semicircular-headed blind arch. The approach walls beyond the refuges also have blind arches, but of wider segmental profile. The voussoirs of all the blind arches are of roughly dressed basalt, without any embellishment. Three rubble stone buttresses shore up the approach wall at the NW end of the bridge. The original stone copings to the parapets appear to have largely been replaced with concrete.

Setting
The bridge sits at the north end of Downhill Forest and is surrounded by woodland to all sites. Just beyond its NW end is a picturesque waterfall on a stream which enters the main one a short distance downstream from the bridge. There is a public footpath into the glen at the SE end of the bridge.

Schedule:
Rubble basalt abutments
Sandstone voussoirs

Historical information

This bridge was erected c.1785 by Frederick Hervey, 4th Earl of Bristol and Bishop of Derry. The 1835 Ordnance Survey Memoir for Dunboe Parish describes it thus: “The Glen Bridge near Downhill has one arch 24ft in the span. The wall is 54ft long, 2ft 6in wide and 1ft 6in thick. The bridge is 16ft 6in broad on the top. This bridge is of excellent architecture and made at the expense of Bishop Hervey. The road leading to this bridge, which is the mountain road to Newtownlimavady from the road at the entrance to Downhill House, is 24ft broad in the clear, in good repair at the expense of Bishop Hervey, now kept in repair at the expense of the county. The architect of this bridge was Michael Shanahan.”
The bridge is shown but not explicitly captioned on all OS map editions from 1831 onwards.

References - Primary sources:
1. PRONI OS/6/5/2/1, First edition OS six-inch map, Co Londonderry sheet 1 (1831).
2. OS Memoir for Dunboe Parish (1835). Reprinted as A. Day & P. McWilliams (eds), Ordnance Survey Memoirs of Ireland: Parishes of County Londonderry III, 1831-5, Roe Valley Lower, p.63 (Belfast: Institute of Irish Studies, 1991).

References – Secondary sources:
1. W.A. McCutcheon, The Industrial Archaeology of Northern Ireland, p.39 (Belfast: HMSO, 1980).

Criteria for listing: architectural interest

A. Style
B. Proportion
C. Ornamentation
D. Plan Form
F. Structural System
H-. Alterations detracting from building
J. Setting

Criteria for listing: historic interest

R. Age
S. Authenticity
U. Historic Associations
V. Authorship
X. Local Interest

Evaluation

An arched rubble masonry road bridge built for Frederick Hervey, 4th Earl of Bristol and Bishop of Derry c.1785, to a design by the Cork architect Michael Shanahan. Although of functional intent, this bridge is also an architectural statement in terms of its symmetrical pedestrian refuges, voussoirs' embellishment and blind arches on both faces. Although relatively modest in scale, its appearance is greatly enhanced by its rustic setting and close proximity to a waterfall which may have been artificially created by blasting.
The bridge's local interest is also enhanced by the fact that it is the work of architect, Michael Shanahan (c.1731-1811), who also constructed Downhill House, Mussenden Temple, and Ballyscullion Houses for the Earl Bishop.

General comments

Listing Criteria R - Age; S - Authenticity and U - Historic Associations also apply.