Cylchlythyr
Map Lleoliad
Geology
The oldest rocks in the Dublin Area are the hard quartzites that make up Bray Head and Howth: originally sandstones deposited during the Cambrian Period over 500 million years ago in the ancient Iapetus Ocean. As the Iapetus Ocean began to close less than 500 million years ago during the Ordovician, volcanic rocks were formed, now found around Balbriggan and Lambay Island. Eventually the Iapetus closed about 400 million years ago during the Devonian and the mountain building event that occurred (the Caledonian Orogeny) caused large masses of granite to form deep in the crust, today forming the Dublin Mountains and Dalkey Island/Killiney Hill. By the early Carboniferous about 350 millsion years ago, the Caldeonian mountains were eroded and a shallow sea covered much of the area around Dublin, depositing limestone found throughout the county. Later geological periods have left no record in the current rock sequences of Dublin, but in the Quaternary Period, staring 1.6 million years ago, ice sheets repeatedly covered the area, eroding rocks and depositing sand and mud. Following retreat of the last ice sheet, many of the current beaches and spits were formed as sea-levels began to stabilise about 5000 years ago.
Bremore
Bremore Point in north County Dublin is famous for its prehistoric passage grave complex of five mounds overlooking the Irish Sea. Bremore megalithic cemetery is located on an eroding headland which consists of 5 Passage tombs, a Mound, a Barrow and a Fulacht Fia. The sea is encroaching on this megalithic cemetery, as striped bedrock is exposed in close proximity to this megalithic complex. The central mound is also the largest mound at 29m in diameter, twice the diameter of the smaller tombs. In the 1940’s the Board of Works took stone from one of the stone mounds to paint Eire in white along the cliff edge of the headland-as part of the Emergency Defences.
The fisher town and harbour of Newhaven was established sometime after 1562, Newhaven is documented on the Down Survey (1655-6) parish and barony maps as a secure harbour for boats and is a considerable place for fishing. The harbour site consists of a substantial dry stone constructed pier and an area of cleared foreshore for pulling up or landing boats. In the mid 17th century, records show the village as comprising up to 10 houses and with a population of 34 people. A customs station was located at Newhaven from at least 1684 onwards to monitor the coastline and to try and control the illegal importation and exportation of goods. Newhaven is depicted on Duncan’s 1821 map of Dublin and therefore may have continued in use as a harbour throughout the eighteenth and nineteenth centuries. Newhaven is not recorded on the 1st OS 6′ map and therefore appears to have gone out of use by this time. The pier acts as the main visible surface evidence of this fishing town today. The pier arcs in a SW-NE direction from the sandy bay forming a narrow harbour entrance with the eroding cliffs to the north. Waves from the south and east have spread the drystone pier boulders into a linear mound along the original pier length that incorporated natural rocky islets. On the south side, the original exterior line of stones can be discerned showing the original structural style of the pier.
Drumanagh
The substantial promontory at Drumanagh was adapted in prehistoric times by the construction of a series of straight earthworks that cut off the promontory from the hinterland. The Discovery Programme as part of the ‘Late Iron Age and “Roman” Ireland’ project identified a D-shaped enclosure, circular ditch, rectangular enclosure and field ditch which is defined by a ditch located south of an 18th century field system. A number of possible pit-like features were interpreted along its circuit. There are 10 promontory recorded in county Dublin, with many other being explored by the CHERISH project due to their island locations in Dublin Bay
There is a Martello tower at the eastern end of the promontory, built in c.1804 as part of the Napoleanic Era defensive structures along the Irish coast. There are 25 martello towers located in County Dublin, and these and other forms of Napoleanic Era structures are common features within many of the CHERISH case study sites as they are often placed on prominent and strategic maritime locations.
Ireland’s Eye
Ireland’s Eye has a fascinating story to tell as it forms part of the Irish Sea chain of islands that have influenced trade, maritime movement patterns and interactions from prehistory through to modern times in the Irish Sea Zone. Today, much evidence of how past societies have interacted with the island can be seen in such examples as its prehistoric sites, Roman finds, early churches, historical accounts of monastic settlements and Viking raids, Napoleonic era defence towers and even murder mysteries. Ireland’s Eye sits off the north Dublin coast. Accretion is was the main coastal process in action along the western coast of the Island. Accretion is a process whereby there is a growth or increase in sediments due to additional materials being deposited. A hard coastline dominates the north, south and east of the Island.
Ireland’s Eye has a fascinating story to tell as it forms part of the Irish Sea chain of islands that have influenced trade, maritime movement patterns and interactions from prehistory through to modern times in the Irish Sea Zone. Today, much evidence of how past societies have interacted with the island can be seen in such examples as its prehistoric sites, Roman finds, early churches, historical accounts of monastic settlements and Viking raids, Napoleonic era defence towers and even murder mysteries. Ireland’s Eye sits off the north Dublin coast. Accretion is was the main coastal process in action along the western coast of the Island. Accretion is a process whereby there is a growth or increase in sediments due to additional materials being deposited. A hard coastline dominates the north, south and east of the Island.
The three sons of Nessan; Dicholla, Munissa, and Nadsluagh erected a church upon the island. The church is referred to as Kilmacnessan or St Nessan’s Church and the three brothers reputedly founded a monastery here in the 6thc AD. The sons of Nessan appear to have been holy men and some dates for its foundation appear to be about 570 AD. The garland of Howth, an illuminated gospel-book, now in Trinity College Dublin, is a remnant of the early monastery and suggests it was a wealthy foundation. Cochrane (1893) debates a 6thc origin for the church but believes it dates before 1235 AD when the church was transferred to the mainland. Ploughing exposed stone coffins in close proximity to the church in 1868, indicating an associated cemetery. A 12thc date is suggested for the church due to the nave and chancel church with a single entrance in the west wall. This is supported by the parallels with the Church of St Michael of Pole and the documentary evidence which dates it to pre 1235 AD. There is no visible evidence of the pre-Norman foundation, no cross-slabs, circular enclosure or architectural fragments. The church was heavily restored in the 19th century.
The Annals of the Four Masters says the island was besieged by Foreigners from Dublin in 897 AD and plundered in 960 AD (Gwynn & Hadcock, 1988). The Annals of the Four Master’s details how the in the late ninth century the Vikings made an encampment which was besieged by Irish forces. Whilst, in 960 AD a Viking fleet plundered the monastery. Another highly visible structure that dominates the north west of the island is a Martello tower. It was established on the Island in 1805/1806 AD as part of the Napoleonic era coastal defence system along the Irish coastline. Many of the visible man made alterations associated with the Islands are a by-product of this construction work, from the harbour on the north west of the Island to the pathways and way markers.
Bull Island
The island known as North Bull Island is constantly changing with the tidal and seasonal movement of sand bars, accretion and erosion. Several shipwrecks have been exposed and covered here. After a storm, it is usual to find loose ship timbers on the beach.Excavations have uncovered 7000-year old fish traps in the River Liffey estuary of Dublin. The Vikings built a town here in the 9th century trading slaves and oriental silks. Since the 16th century, historical records reveal at least 800 shipwrecks in Dublin Bay. This wrecking led to the North Wall construction by 1824 to protect these ships entering Dublin harbour. This changed the flow of sediment in the bay and led to the growth of a 5km-long sandy Bull Island.A file in the National Museum of Ireland records a corroded double-edged blade and tang iron sword found in sand near Dollymount in 1872. Dollymount Strand is the name of the beach on Bull Island. The sword is on display in the Viking section of the museum. Maps and charts from the 18th and 19th century show shipwrecks on the sand flats. In the 18th century, the South Wall battery fired upon shipwrecks plunderers with some jailed. Loose ship timbers and wooden shipwrecks periodically appear after storms on the sand flats and amongst shifting sand bars.
Intertidal survey by CHERISH is recording these shipwrecks on Bull Island when they appear and change after storms and seasonally. We are measuring beach profiles over the shipwrecks. Geophysics is determining the extent of buried sections of shipwrecks. LiDAR and mobile mapping from a vehicle are also surveying the 5km long beach.
Dalkey Islands
Dalkey sound acted as a natural harbour, the sound separates Dalkey Island from the Mainland. The activity on Dalkey draws parallels to Ireland’s Eye and the other Dublin Bay Islands. The island shows evidence of activity from the Mesolithic period onwards. Excavations in the 1950s by David Liversage on two shell midddens produced archaeological material from various such as Bell Beaker pottery from the later Neolithic whilst Roman finds of glass, beads and pottery show interaction in the Iron Age, this later material is possibly contemporary to the promontory fort on the Island.
Dalkey Island has a church, crosses, burials and a holy well. In the first few centuries of the early medieval period, Dalkey Island formed part of the area of the Uí Briúin Chualann who controlled a territory including the seaborne side of north Wicklow, Killiney Head and Dalkey Islands. Within this area, two churches dedicated to Saint Begnet were founded, one on Dalkey Island and the other in Dalkey town. While the surviving stone church of Saint Begnet’s in Dalkey town appears of a later design than the church on Dalkey Island
During the ninth century, the Scandinavian settlers of Dublin are believed to have controlled a territorial area from Lusk to Dalkey, and probably also controlled a significant maritime hinterland including all the Dublin islands. The immediate Hiberno-Norse association with the name Dalkey, suggested as a Norse translation of the Irish name ‘Deilginis’ or thorn/dagger island, possibly are present within the Annals of the Four Masters. Dublin functioned as an important centre for slave trading (Oftedal, 1976) and Dalkey Islands were part of the Dublin Hiberno-Norse kingdom of Dyflinaskiri. In addition to the use of Dalkey for holding slaves in the tenth century, the island also functioned as a refuge.
The Martello tower and associated gun battery were constructed c.1804-5, and the ownership of the island passed from the archbishop of Dublin to the Board of Ordnance who maintained the island as a military base throughout the nineteenth century, though cattle grazing rights continued to be granted. Walk over survey on the island recorded sediment exposures along the coastline of the island due to erosion and wave impact. Within these exposures a variety of artefacts types were identified from flint nodules to worked flints, iron concretions, slag, coal and North African pottery fragments.
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