Monument record 1682/3/9 - Tunnel, Kirby Hall

{1} The diversion of an existing watercourse led to the construction of a subterranean passgae or 'tunnel', which survived beneath the West Terrace within c. 15m of the south-west corner of the later garden. Part of the tunnel had been breached by the construction trench of the limestone wall which formed the outside of the subsequent terrace, and one of its sides was used to support a stretch of that walling. Within the garden, the stone foundation of the inner terrace-revetment similarly cut through and blocked the passge; it had been additionally broken into and was further backfilled during later remodelling of the bank.
The course of the tunnel ran approximately east-west, veering slighlty southwards at one point. The structure comprised a long, roomy passgae, 1.32m high and 0.9m wide, which was skilfully built in horizontal course of largely undressed stone bloscks bedded in yellow sand. The vertical sides of the tunnel rose to a carefully contrived barrel vault. The floor of natural bedrock was covered by only a thin layer of grey silty clay, but the size of the overall feature is such that it could have been scoured periodically. The roof had collapsed at a point c. 14m from the inner edge of the West Terrace and near to a possible niche in the south side, as denoted by a lintel which was reddened by heat and smoke-blackened on the underside.
At a further distance of c. 5m to the west , where the tunnel was exposed at the outer wall of the later terrace, the passage turned northwards at almost a right-angle to terminate in a rectangular chamber, 1.68m long by 0.69m wide. The roof-gap was here bridged by long lintel slabs which were susequently used to support the retaining wall of the terrace where it oversailed the west side of the chamber.
Beneath the overhang of the later wall the side of the chamber was built of ashlar blocks around a large, roughly square opening, 0.61m high and 0.58m wide, which connected the northern end with a rock-cut channel outside. The chamber may have acted as a silt-trap, with its construction facilitating periodic emptying in a manner that was not possible in the confines of the main tunnel. The soil and stones which filled the outside channel had spilled into the aperture and partly within the chamber, where they overlay a discontinuous layer of morat that had splashed onto the surface of a thin basal silt. Backfilling therefore appears to have occurred when the terrace wall was constructed, implying that the tunnel was a feature of the existing garden.
The opening into the tunnel appears to have been located along a former boundary represented elsewhere by a limestone wall of varying construction and quality (and indeterminate dimensions) which was similarly oversailed by the later terrace revetment.

<1> Dix B.; Soden I.; Hylton T., 1995, Kirby Hall and Its Gardens: Excavations in 1987-1994, p.331 (unchecked) (Report). SNN74020.

Record last edited

Aug 28 2014 5:02PM