Waterford

Heritage Sites of Co. Waterford

Reginald’s Tower, Waterford

In Ireland many early towns were walled for protection and these would have had gates and protective towers. Built of the predominant stone found in the immediate neighbourhood this would have been limestone in Dublin, Limerick, Cashel and Galway while in Derry sandstone and slate would have been used.  While many of the walls have long disappeared and the stonework purloined for later construction elements, those of most cities still survive albeit in fragmentary form for the most part.

Reginald’s Tower in Waterford was built, it is believed in 1003, as a defensive structure and was later incorporated as an integral part of that city’s wall.  The earliest image of it, dating from 1373, is on the Charter Roll of the Corporation Waterford that also depicts at least six other towers protecting the city, all of which have now disappeared.

According to George Wilkinson, in his seminal book Practical Geology and Ancient Architecture of Ireland (1845), the stone for the Reginald’s Tower was obtained from Grange Hill, 1.2 km south of the city.  There, a green to grey coloured volcanic ash called felsite crops out and as recently as the 1900s active quarrying of this stone occurred in the area. Three small quarries are marked on the Ordnance Survey map of 1913, the largest of which was located 50 m east of Gortmore House.  This stone is composed of ash, which was produced during violent volcanic eruptions during the Ordovician period 460 million years ago; this fine-grained material settled out and while hot became fused to form a tough, hard-wearing rock, which could be crudely dressed and fashioned for building. 

The tower, which is just over 13 m in diameter and 15 m in height, shows evidence of having been partially rebuilt in the past; these later repairs can be visually picked out through identifying the slightly different style of finish and arrangement of the masonry used.  The tower has been witness to many episodes of conflict and bears the scars: a cannonball is embedded deep within the 3 m thick walls just below the parapet.  The lower parts of the tower are constructed in olive green to grey rubble masonry whereas higher up a russet brown, more blockier stone is used in places.  Grey Mississippian limestone frames the doorway at street level, which is a later insertion.  Originally the main entrance was higher up and reached via the city wall.  Some windows are framed in grey limestone and this was also used for the carved plaque above the door.

Reginald’s Tower has had many uses over a thousand years and been given a number of names, including the Ring Tower or Dundory, the King’s Fort.  It may have been part of a royal castle, it was the location of a Mint in the 1170s (examples of coins struck there are now very rare) and today it houses part of the Waterford Museum of Treasures.

Geology of Co. Waterford

The Precambrian rocks in Waterford are 600 million years old [Ma] and are now metamorphosed or altered sediments that were first deposited into an ocean and later changed during a mountain-building event. During the Ordovician period (488-444 Ma) shallow water limestones and some deeper-water muds were laid down in the Iapetus Ocean that divided Ireland into two. The Tramore Limestone dates from this time and contains bell-shaped fossil bryozoans called Diplotrypa. Some brachiopods (shells) and trilobites (arthropods, like Horseshoe Crabs) have also been found. As this ocean slowly closed the continents on either side were subjected to great stress and volcanoes produced lavas and ash during eruptions. Along the coast at Kilfarrassy and Bonmahon these volcanic rocks can be seen. During the Silurian period sediments continued to be deposited in the ocean that finally closed. This closure caused another mountain building event to take place causing many of the Silurian rocks to be tilted and then eroded away.

A new continent was created in the Devonian, around 400 Ma, as the Iapetus Ocean closed. Large rivers drained from the newly formed mountains and deposited great thicknesses of sand and gravel on the flood plains. In a few places these Devonian rocks can be seen lying on an ancient erosion surface on steeply tilted older rocks. The boundary between them is called an unconformity. These sandstones and conglomerates (pebble beds) now form all of the higher ground, above 200 metres, in the county, such as the Comeragh and Knockmealdown mountains. By about 360 Ma, at the start of the Carboniferous, sea level was slowly rising and it drowned the flood plains. The limestones deposited in this warm, shallow equatorial sea now form much of the low ground across the county.

After the Ice Age the rivers in southern Ireland flowed north to south. As they eroded downwards the upstream parts of rivers were re-orientated by the underlying east to west trend of the landscape in south Munster. The River Blackwater flows for most of its length eastwards but at Cappoquin makes a marked right-hand turn and flows south to Youghal.

Map legend: Geological Map of Limerick (based on GSI 1:1,000,000 map 2003). Light purple: Precambrian metamorphic rocks; Pink: Ordovician; Dark blue: Ordovician volcanic rocks; Green: Silurian sediments; Beige: Devonian sandstones and conglomerates; Light blue: Lower Carboniferous limestone.