Alum, Alchemy and Ammonites

The East Cleveland landscape was shaped by a unique industrial process that went on here for over 250 years. This area was once the only place in the UK where Alum was produced. Alum is a chemical compound used to fix dyes, and in the preserving of leather and was pivotal in the growth of industry in the Cleveland and North Yorkshire area. The project entitled ‘Alum, Alchemy and Ammonites’ was awarded £46,300 to the Tees Valley Wildlife Trust from the National Lottery through the Heritage Lottery Fund to explore what effects this quarrying had on the landscape, and the contributions it made to industrial history and earth science.

What is alum?

Alum is a complex double salt of aluminium sulphate and ammonia or potassium sulphate.

K,Na.Al(SO4)2.12H2O

It is a clear crystal that solidifies easily out of solution and forms large regular crystals.

The large alum crystal shows the type of alum that would grow in the barrels at the alum house

These would then be ground into a powder and put in sacks to take to London to sell.

Alum was mainly used in the dyeing industry, as a mordant to fix dyes to fabric, but it was also used to preserve leather, in paper making, as a fire retardant and for making quill pens.

What are ammonites?

When walking along the beaches, and through the countryside around East Cleveland you have probably seen an ammonite fossil. They are very common in the rocks in this area and have played such an important part in the local history they even feature in the town crest for Whitby.

Ammonites are one of many types of fossils found in the local rocks. They became extinct at the same time as the dinosaurs, 65 million years ago, but were once common inhabitants of the shallow tropical seas which occupied Cleveland and North Yorkshire during the Lower Jurassic Period between around 200 million and 175 million years ago.

Fossil ammonites take the form of coiled shells produced by creatures related to modern day octopus and squid. They are named after the Greek God Ammon, who had coiled horns like a ram.

These sea creatures lived within the protection of their shells and moved around by means of jet propulsion, squirting water from a tube known as a syphon situated near the creature's head.

Many ammonites occur within the local alum shale and were recognised as being important in dating rock units by Loftus-born scientist Lewis Hunton (1814-1838). Today these fossils are used by geologists worldwide to do just this.

For a long time people belived that ammonites were the remains of snakes, turned to stone by St. Hilda, when she first came to Whitby. To commemorate this there is a type of ammonite named after St. Hilda, the hildoceras.

The Huntons: Loftus Alum Makers

The appearance of the alum trade in North Yorkshire brought with it not only a solution to Britain’s need for this invaluable chemical, but also a newly-kindled interest in the rocks of the district. While the landed gentry made profit from their alum works another family, the Huntons of Loftus, made important contributions to geology at a time when the systematic study of rocks was in its infancy.

It could almost be said that Lewis Hunton had alum in his blood. His father, William (1789-1863) was the Alum Agent at Loftus alum works and his grandfather, also called William (1761-1809), had been an alum maker at Loftus alum works.

Christened in St.Leonard’s church, Loftus on 6th August 1814, Lewis was the first of William’s nine children by his wife Jane March – all born at Hummersea House, Loftus. Three of Lewis’s sisters died very young: Eliza aged 21 weeks, another Eliza aged just 4 weeks and Margaret Coatsworth Hunton aged 6 years. Two other sisters, Jane (1824-1853) and Elizabeth Mary (1830-1853) died before the age of 30.

The three remaining siblings were: Ann (born 1816), William (1820-1852) and Robert March Hunton (1822-1871). Robert and William also became alum workers.
William seems to have abandoned the alum industry prior to his death in Hull on 11th April 1852; whilst Robert became a ship-owner (possibly still connected with the alum trade) prior to his death in Whitby in August 1871.

Several members of the family are buried in a row of closely adjacent graves in St.Leonard’s churchyard. Those members of the family who died in more distant places are commemorated on headstones in the same row.

Lewis’s death is one that is commemorated in this fashion. He died of consumption (TB) in the Auvergne region of France near Nimes on 17th February 1838. Although his life was a short one, he made a significant contribution to the study of geology thanks to his intimate knowledge of the local rocks.

Lewis Hunton wrote one short scientific article at the age of 21 and died two years later in 1838. Yet this little known local figure was years ahead of his time and invented what we now call Biostratigraphy – a cornerstone of the science of geology.

William Smith, known as the father of English Geology, had already put forward the idea that “Strata may be recognised by their organised fossils” before Hunton carried out his work, but Smith’s understanding was broad and sweeping. It applied to great thicknesses of rock like the Lias, the Oolite or the Chalk, all of these are hundreds of metres thick.

Other people involved in the early development of the science of geology, like Rev. George Young and John Bird who also worked on the cliffs around Whitby, didn’t even believe Smith’s simple idea.

Lewis Hunton made a number of great leaps forward in his understanding of the sequence of the local rocks and the fossils they contain. First of all he noticed that each type of fossil had a limited vertical range, thus a fossil may be very common within a narrow band and not found outside it.

Today we would understand this as related evolution, which was only proposed by Charles Darwin 20 years after Hunton’s article was read to the Geological Society of London. So as animals evolve through time, each successive layer of rock contains a different collection of fossils.

The second major leap that Hunton made was to recognise the huge importance of ammonites. These animals evolved quickly, so the shape of their fossils changes rapidly through successive layers of rock. This means that each species can be used to identify quite narrow bands of rock, unlike some very slowly evolving animals which remain the same for huge periods of time and do not help categorise individual layers.

What may now seem obvious was a giant step in the early 19th Century. Lewis Hunton did not live to see the impact of his work, but his legacy has been huge. Hundreds, if not thousands of scientists round the world have been applying his rules to layers of rock for almost 200 years. We now use all sorts of different fossils, including some which need powerful microscopes to see, but Hunton’s ammonites remain the best biostratigraphic fossils for the Jurassic. Not only this, but some of the layers he defined by the typical ammonites they contain are still used across Europe today.

Finally and perhaps most importantly, Lewis Hunton emphasised that fossils need to be collected in-situ. Prior to Hunton pretty fossils were collected that had fallen out of the cliff naturally.

What he understood was that you need to do the painstaking work of carefully collecting fossils from the actual beds in which they occur. From this you could build up an accurate description of the diverse set of animals that were living at any one time, and focus upon those which were typical and diagnostic of each layer.

Places to visit

The alum quarries and the alum works have gone, made redundant by developments in technology. Most of the inland sites closed in the eighteenth century, overtaken by the more efficient works on the coast. Belman Bank and the major coastal sites of Loftus, Boulby, Sandsend and Peak kept working until the 1860s and 1870s until they too became uneconomic.

What is left is a series of altered landscapes. The busy quarries and works of this massive industry stand now like ghosts. Located in the spectacular and tranquil scenery of the moors and coast, they are fascinating places to visit – full of history and touched by magic.