2010:600 - Sligo, Sligo

Monitoring of engineering slit-trenches and test-pits in advance of the proposed Sligo town water conservation scheme took place around Sligo town and environs between mid-October and mid-November 2010. Moore Archaeological and Environmental Services Ltd, in a previous assessment (March 2010) for the project, had demarcated a defined area of archaeological potential around the medieval centre of the borough. Within this area all groundworks associated with the site investigations were monitored. The slit-trenches ranged from 5–15m but were typically 10m in length by 0.55–0.8m in width. All trenches were mechanically excavated to an average depth of 1.3m. Depths did vary depending on the location of services and occasionally exceeded 2.5m. Using existing service maps as a guide, the contractors attempted to determine the location, depth and extent of the in situ pipework.
The service infrastructure encountered ranged from 19th-century stone and brick culverts, lead pipes, cast-iron mains and more modern services. Due to the multiplicity of services, the stratigraphic profile generally consisted of upper deposits (0.3–0.5m) of modern fills including gravels and coarse sand overlying redeposited sand and occasionally builders fill (up to 0.7m in depth). Natural clayey sand with a medium amount of stones varied in depth given the level of disturbance but ranged from 0.4m to 1m. Near the banks of the Garvogue River and along what would have been the old flood-plain, much of the subsurface deposits were made up of a composite of redeposited alluvial silts and sand. The underlying parent material throughout the subject area consisted of compact calcareous gravelly loam till of predominantly carboniferous limestone composition. Weathered bedrock was occasionally encountered, particularly on the northern bank of the river, but not in concentrations that impeded the works.
During the course of the monitoring brief, very few in situ deposits of archaeological potential were identified. This was partially due to the fact that, when services were exposed, digging ceased and it was not possible to investigate the material below. Furthermore, much of the underlying deposits along the streets of Sligo have been disturbed or removed by modern excavations.
The following section presents the results of the monitoring programme in tabulated form.
John’s Street
Six 10m-long slit-trenches and eleven test-pits were excavated along the length of John’s Street in the vicinity of the graveyard of the Church of Ireland cathedral. Excavations along the roadway exposed modern fills below the road base overlying a natural grey/brown, clayey sand with occasional medium-sized stones. Within the fill material for the older services, including the stone culvert (c. 1850s) and the original cast-iron water main, were a number of disarticulated animal-bone fragments; these remains were noted but were not considered significant. Other stray finds included occasional modern pottery sherds and metal debris. There was no evidence of earlier structural remains or finds or materials of archaeological potential.
Smith’s Row and City Centre Carpark
Five 5m slit-trenches were excavated along the length of Smith’s Row and the adjoining car park. Excavations exposed modern rubble fill below the road base overlying a natural grey/brown clayey sand. Within ST5–088O along the west of the car park there was evidence for a dark organic horizon at a depth of 0.4m that contained fragments of red brick. No other stray finds were recovered or materials or features of archaeological potential were evidenced.
Pearse Road
Five 10m slit-trenches and two test-pits were excavated along the length of Pearse Road between the junction of Old Market Street and Burton Street. Excavations exposed a number of modern services cut into a grey/brown compact natural sand. There were no finds, features or materials of archaeological potential noted in this area.
Old Market Street
Four 10m slit-trenches were excavated along the length of Old Market Street between Pearse Road and Burton Street. Excavations exposed a number of modern services cut into a rubble layer with old builders’ fill and grey/brown compact natural sand, particularly in ST10–117. It is worth noting that there are a number of in situ cobbled areas along the western side of this street that have the potential to protect earlier historic layers. There were no other finds, features or materials of archaeological potential noted in this area.
Connolly Street
Seven 10m slit-trenches and five test-pits were excavated along the length of Connolly Street and the junction of Mail Coach Road. Excavations exposed a number of modern services cut into a compact grey/brown natural sand. The only notable feature was found in ST5–127 to the south of the street. Beneath the road base at a depth of 0.5m was a brown organic-rich deposit containing a concentration of both oyster and periwinkle shells. This in situ historic layer has moderate potential to contain finds of archaeological significance.
The Mall
Thirteen 10m slit-trenches and six test-pits were excavated along the length of The Mall. Excavations exposed the usual frequency of modern services cut into road base, modern fills and grey/brown compact natural sand. The one exception was a layer of cobbles exposed under the footpath at ST10–035. These cobbles represent an old surface that possibly pre-dates the existing Georgian terrace (originally Gore Street). The cobbles were well sorted and made up of water-rolled, sub-rounded stones in a compact layer. The depth of the cobbles relative to the adjacent properties suggests a mid-18th-century date.
Further west along the mall, in the vicinity of the car park, the stratigraphy had a deposit of builders’ fill under the road base consisting of dumped stone, plaster, mortar and red brick. There were no additional finds, features or materials of archaeological potential noted in this area.
Holborn Street
Three 10m slit-trenches were excavated along the southern half of Holborn Street. Excavations exposed a prevalence of modern services cut into a deposit of brown clayey sand overlying grey/brown natural sand. A number of disarticulated animal bones and shell were noted in ST05–073. There were no other finds, features or materials of archaeological potential noted in the area.
Stephen’s Street and Stephen’s Street Carpark
Eight slit-trenches were excavated along Stephen’s Street and the adjoining carpark. Along the road the stratigraphy was mostly made up of modern infill overlying natural clay. Within the car park, however, in slit-trenches ST5–076 and ST5–078, a layer of dark organic material was observed at a depth of 0.3m. This layer had fragments of red brick. There were no other finds, features or materials of archaeological potential noted in the area.
Teeling Street
Four slit-trenches and two test-pits were excavated along Teeling Street. The stratigraphic profile was made up of underlying modern infill over natural clay. There were no finds, features or materials of archaeological potential noted elsewhere in the area.
Thomas Street
Three slit-trenches and two test-pits were excavated along Thomas Street. The stratigraphic profile was as previously described. ST10–84 along the bridge was dug to a depth of approximately 2m and was made up of redeposited sandy soil with occasional medium-sized stones. The remaining slit-trenches exposed a red-brick culvert probably dating to the 1850s. A small concentration of oyster shell was noted in the fill over the old water main.
Bridge Street
Three slit-trenches were excavated along Bridge Street. Within ST10–079, to the north of the road, a cobbled layer was exposed at a depth of 0.65m. These cobbles were located 3m from the western terminal and extended under the footpath. To the east they were truncated by a modern service. Elsewhere the stratigraphic profile consisted of red/brown silty sand overlying natural dark-brown clayey sand.
Castle Street
Three slit-trenches were excavated along Castle Street. Groundworks exposed the usual frequency of services, including the old stone-lined culvert. Within ST10–092 a silty deposit was found at a depth of 0.55m containing concentrations of seashells. This layer was partially truncated by a broadband installation. Elsewhere the stratigraphic profile consisted of road base overlying redeposited rubble fill and natural sand. There were no other finds, features or materials of archaeological potential noted in the area.
Grattan Street
Two slit-trenches were excavated along Grattan Street exposing a large red-brick vaulted culvert lying beside more modern services. Due to the extent of previous disturbance there was not much natural ground visible. There were no finds, features or materials of archaeological potential noted in this area.
O’Connell Street
There were no slit-trenches excavated in O’Connell Street; however, there were a number of test-pits excavated. All of these were sited to investigate specific services and therefore were of no archaeological interest.
Wine Street
Seven slit-trenches were excavated along Wine Street exposing mostly redeposited service fills overlying grey/brown natural sand. Occasionally beneath the road base was a dump of builders’ fill containing rubble stone and red-brick fragments. There were no finds, features or materials of archaeological potential noted in this area.
Quay Street
Four slit-trenches were excavated along Quay Street at night exposing mostly infilled ground with builders’ rubble and fragments of red brick over a stone-lined culvert and more modern services. There were no finds, features or materials of archaeological potential noted in this area.
Knox Street Lower
Two slit-trenches were excavated along Lower Knox Street exposing disturbed sandy ground cut with modern services and fills. There were no finds, features or materials of archaeological potential noted in this area.
Quay Street Lower
Five slit-trenches were excavated along Lower Quay Street exposing a number of services including broadband ducts and a cast-iron water main cut into redeposited compact grey/brown sand. Along the middle of the street, near a possible late-18th-century property, excavations in ST10–65 uncovered a small rubble stone and mortar wall foundation that ran across the width of the trench and measured 0.3m wide by 0.35m in height. The wall was roughly orientated north–south and was located 0.3m from the footpath on the eastern side of the trench. The wall was constructed of cobble-sized sub-rounded and sub-angular stones and was bonded with a dense sandy mortar with shell inclusions. Three courses of stone were exposed. Several deposits including an ash deposit and brick inclusions were visible in the south-facing section on the western side of the wall. Deposits on the eastern side of the wall had been disturbed and backfilled with hardcore. There were no finds, features or materials of archaeological potential noted in the remaining trenches.
Union Street
Five slit-trenches were excavated along Union Street exposing mostly modern infill with little evidence for in situ deposits. There were no finds, features or materials of archaeological potential noted in this area.
Despite years of successive redevelopments and street widening it is still possible to encounter in situ material with significant archaeological potential. During the monitoring programme cobbles were found both along The Mall and Bridge Street. In Quay Street an unrecorded wall foundation was exposed, which could be associated with structural remains from the old harbour. Within the town centre 19th-century stone- and brick-lined culverts and more recent service works have removed much of the earlier deposits along the roadways. Notwithstanding this, in outlying streets, notably Connolly Street and to a lesser extent Holborn Sreet and Thomas Street, there were occasional pockets of organic-rich material that contained disarticulated animal bone and shell. These dump deposits generally contain finds and are of archaeological interest. Also evident from within the slit-trenches were dumps of builders’ rubble. This material has the potential to contain medieval fabric or architectural fragments.