Vincent Butler Heritage – Page 3 – Archaeologist, Heritage Specialist, Tourism & Training

At The Cutting Edge

Chalk is a sedimentary rock which formed on an ancient seabed around 75 million years ago in the Cretaceous Period. It is mainly composed of the accumulated fossilised remains of micro-organisms known as coccolithophores. These are a type of phytoplankton which secrete a calcium-rich protective shell made up of around 30 separate connected plates known as coccoliths, each of which is a mere 3 one-thousands of a millimetre in diameter. Pretty small for sure! Incalculable numbers of these minuscule shells rained down onto the seabed and were subsequently compressed, compacted and cemented together over millions of years to form the distinctive white coloured rock, the name for which derives from the Latin word ‘creta’ meaning simply ‘chalk’.

The famous White Cliffs of Dover in England are composed of it. This rock once covered most of the island of Ireland but, through the combined processes of weathering and erosion over millions of years, has been stripped away. Mainly only surviving in Co. Antrim, where it is covered by a protective layer of basalt, it is visible as a thick white band along the coast. Flint occurs as irregularly shaped nodules in the chalk and, fracturing into flakes when struck with a hammerstone, was an ideal material from which prehistoric people fashioned everyday tools and weapons. It is a type of quartz

Flint nodules from beach shingle, Wexford

The only sizable exposed in-situ source for flint in Ireland is in Co. Antrim. However, during the last Ice Age an extensive ice sheet filled the Irish Sea basin and, as it moved southward, bulldozed the sediments and underlying rock layers on the seabed. This material was later deposited by the melting ice as boulder clay on land, since which time large quantities of flint nodules have been eroded out and are now incorporated in the shingle on beaches along our eastern seaboard. The same boulder clay contains marine shells, including oyster (Ostrea edulis), which are certainly tens of thousands of years old. The art of flaking flint is known as ‘knapping’ and the resultant flakes were retouched by craftsmen who produced a range of items including knife blades, scrapers and projectile points. The consummate skill of one of our Neolithic forebears is readily apparent from this arrowhead which dates to sometime around 5,000 years ago.

The earliest evidence to date for the use of flint in Ireland comes in the guise of cut marks on the front surface of a brown bear’s kneecap which has been dated to 10,500 BC. Inflicted by a flint blade when the carcass of the bear was being butchered, the marks were originally noted in 1903 by the team who excavated the ancient deposits in a cave near Ennis, Co. Clare. It was found along with thousands of other animal bone fragments. This makes the butchered kneecap the earliest definitive evidence for the presence of humans in Ireland, the only other explanation being that it belonged to a self-butchering bear!

Chert is almost chemically identical to flint and was also used as raw material for making tools and weapons in our prehistoric past. Mesolithic hunter-gathers established a temporary camp on the shores of what was a shallow inland lake 8,500 years ago. The site is today known as Lough Boora, in Co. Offaly. Here they made tiny flakes or microliths from locally available chert. Only a few centimetres long, a number of these would have been mounted together as part of a composite implement, perhaps a spear or such like, used for fishing, hunting and fowling. Chert is found in Carboniferous limestone, Ireland’s commonest rock, in the form of thin bands and nodules.

Obsidian is a black volcanic glass which, just like flint, fractures when struck. Its flakes were worked into razor-sharp tools and weapons. An important source is centred on Lipari in the Aeolian Islands north of Sicily. Recent archaeological research has established that the volcanic glass from this island was traded widely in prehistoric times.

Best,

Vincent

Tags cretaceous, flint, fossil, neolithic, nodules, obsidian

Cabinet of Curiosities

A Penny For Your Thoughts

When James’s II arrived in Ireland in 1689 to prepare for the showdown with his estranged son-in-law King William, in what would manifest as the Battle of the Boyne the following year, he was somewhat strapped for cash. Wars are a costly pastime and as a means of paying his army he ordered that coins be struck from base metals. Defunct cannons were melted down in numbers for this purpose and is the origin of the name ‘gunmoney’ for this series of coins. In fact other metal objects including church bells were also used. In denominations of crowns, halfcrowns, shillings and sixpences, the coins were struck in mints in Dublin and Limerick. The plan was that his supporters would exchange them for silver coins once victory had been secured. Unfortunately for the Stuart king, this never came to fruition and the men who had fought for him were left out of pocket. The coins were initially devalued, and then later completely banned, by King William and his wife Mary. The coin here is a James II shilling and was struck in October 1689. The obverse of the coin features his profile and bears the Latin inscription ‘JACOBUS II : DEI GRATIA’ – ‘James II : by the Grace of God’.

From the leafy banks of the River Boyne on July 1^st1690, our attention is now drawn to a military engagement in quite a different league 226 years later in France. The first day of the Battle of the Somme took place on July 1^st 1916. Fourteen divisions of British troops held a 23 km long front. The 120,000 soldiers waited anxiously in their trenches for the order to ‘go over’. If the Allies had been successful in pushing through the German lines this would have been a decisive action in the war. Unfortunately, it failed. On the first day alone there were over 60,000 British casualties, of which 20,000 were killed. The Battle of the Somme dragged on for another five months. The British Army sustained a total of 420,000 casualties by the end of the offensive, with a figure of around 500,000 for the Germans. It was a staggering price to be paid in human terms for the mere six miles of ground that had been gained. This 1912 penny was recovered from the Somme Battlefield. It was struck by a bullet which, although inflicting damage, did not pass through the coin. A split second in this world conflict frozen in the dented metal and carrying with it a gossamer-fragile hope that it may have saved its owner. A lucky penny perhaps!

Copper has been mined in Ireland since the Bronze Age around 2,400 BC. A green patina forms when the metal weathers and so its presence in a rock body was easy to spot by prehistoric prospectors. Early metalsmiths blended copper with small amounts of tin to produce the alloy bronze, from which a wide range of tools, weapons and other everyday items were made.

Fuelled by European colonial expansionism between the sixteenth and nineteenth centuries, a lucrative trade in slaves developed from which vast wealth was generated. Ships with cargoes of guns, cloth and base metals, to be used for buying slaves, journeyed from Europe to Africa. With their human cargo stowed, the same ships then sailed across to the Americas where the poor unfortunates were sold to plantation owners. The final leg of the journey saw the ships return to Britain and other European countries laden with coffee, cocoa, sugar, cotton and tobacco. This combined route is referred to as the Triangular Trade.

In 1843 a slave ship called the ‘Duoro’ sank off the Isles of Scilly, Cornwall, on its way to the western coast of Africa. In its hold was a large consignment of ‘manillas’, a type of slave token. Local chiefs were involved in the gathering of fellow Africans who were then exchanged on a barter system for a range of different commodities, one of which was the manilla. These bronze ‘bracelets’ were made in Birmingham and exchanged by the traders for slaves. They were worn as jewellery or a sign of status and also melted down for their metal. This manilla was recovered from the wreck of the Duoro.

Best,

Vincent

Tags battleoftheboyne, battleofthesomme, gunmoney, slavetoken

Cabinet of Curiosities

A Burning Issue

The compressed remains of ancient plants

When you pick up a piece of coal you hold in your hand the compressed fossilised remnants of a primeval forest. Around 300 million years ago, a time when most of what we now call Ireland lay about 10 degrees south of the equator, giant tree-ferns and clubmosses flourished in hot, humid conditions which saw the development of extensive areas of swamp. Over time, as the plants died, their remains accumulated in the prevailing waterlogged conditions and formed thick layers of semi-rotted dead vegetation or peat. This period was characterised by fluctuations in sea level which rose and fell on numerous occasions. Each rise flooded the swamps and covered the peat layers in deposits of silt and sand. When the water level once again fell, new swamps clothed in vegetation became established and so the cycle repeated itself many times over millions of years. During the passage of time, the alternating layers of silt, sand and peat were compressed and compacted into layers of shale, sandstone and coal respectively, comparable in a sense to a gigantic, multi-layered rock sandwich. This occured in the latter stages of the geological period called the Carboniferous, meaning ‘carbon-bearing’, a reference to the extensive coal deposits which were laid down at that time..

One of the main groups of plants growing in the swamp forests were the lycopods. These were giant clubmosses, some of which attained tree-size proportions. They include a species known as lepidodendron, which could reach heights of up to 38 metres. Its ‘root’ system is known in the fossil record as stigmaria and has a readily recognisable ‘dimpled’ pattern. Another common fossil clubmoss is sigillaria. It takes around 15 cm of peat to form 1 cm of coal. The large sample I am holding was gifted to me in 1977 by a friend whose father owned a fuel depot in Harold’s Cross in Dublin. It is 20 cm in thickness and therefore represents the compressed remains of a 3-metre deposit of ancient peat and weighs 10 kg. The upper surface displays the linear pattern of the trunk of a Sigillaria. It is estimated that as much as 70% of the coal in some deposits may consist of the compacted remains of lycopods. Smaller plants also grew in those tropical forests including many species of fern and Pennsylvania in the USA is famous for them. I regularly check through my coal before consigning it to the flames and over the years have been amply rewarded with some nice fossils.

Clay-ironstone nodules are natural concretions which occur in shale and are commonly found during coal mining. They are composed of a blend of fine clay particles and an iron mineral known as siderite. Also known as ‘iron balls’, they were processed from the mid-sixteenth century onwards as a source of iron when coal extraction began in the Castlecomer area of Kilkenny. Indeed, some of the railings and gates in the locality are made of ‘Castlecomer iron’. The nineteenth-century ironworks in Arigna, Co. Roscommon, was supplied with siderite-rich nodules collected by men and women in the layers of shale exposed along the courses of the local rivers.

Clay-ironstone nodules come in a variety of shapes and sizes and over the years I have amassed a significant collection. When the Bru na Bóinne Visitor Centre in Co. Meath was being built some years ago, the machines removed vast quantities of the local shale and some large nodules surfaced. Some of these were retained and later incorporated in the water feature located just outside the main entrance to the centre. The largest specimen I have ever come across on my travels is on display outside the Natural History Museum in Bordeaux in France.

Best,

Vincent

Tags carboniferousfossils, fossilplants, nodules