Tees Valley RIGS Group

Welcome to the Tees Valley RIGS group website. This website is designed to give you more information about the geology of the Tees Valley. Whether you are a beginner or a keen geologist we hope that you will find everything that you need.

To get you started why not try one of our Geotrails and take a walk around some of our famous sights and our hidden gems.

This site was developed with the kind support of Natural England through Defra’s Aggregates Levy Sustainability Fund.

References and Further Reading

The following documents may be useful for those wishing to learn more about the links between geology and the Tees Valley.

The Geology and Mineral Resources of Yorkshire

Edited by D.H. Rayner and J.E. Hemingway
Yorkshire Geological Society. 1974.

The Geology of Northumberland and Durham

Proceedings of the Geologist’s Association Vol. XLII Part 3, pp 217-296 1931.

Along the Scar

Denis Goldring
Peter Tuffs Publications. 2001.

The Floating Egg

Roger Osborne,
Pimlico. 1999.

Cleveland Iron and Steel – Background and Nineteenth Century History

J.K. Almond and others
British Steel Corporation. 1979.

British Mesozoic Fossils

Natural History Museum
Intercept. 2001.

Geology Explained in the Yorkshire Dales and on the Yorkshire Coast

Derek Brumhead
David and Charles. 1979.

Understanding The Earth – a new synthesis

Edited by G.C. Brown, C.J. Hawkesworth and R.C.L. Wilson
Cambridge University Press. 1992.

A New Geology

M.J. Bradshaw
Hodder and Stoughton Ltd. 1973.

Geological Science

Andrew McLeish
Thomas Nelson and Sons Ltd. 1986.

Chronology of the Development of the Iron and Steel Industries of Tees-side

K. H. R. Edwards
By Author 1955

The Tees Valley RIGS group was set up in 2003 to catalogue all sites of geologic or geomorphic interest in the Tees Valley and try to get them recognised to protect them for the future. Regionally Important Geologic and Geomorphic Sites (RIGS), designated by locally driven criteria, are currently the most important places for geology and geomorphology outside statutorily protected land such as Site of Special Scientific Interest (SSSI). A locally determined RIGS designation at a location of one way of recognising and protecting geodiversity for the future.

Between 1990 and 1997 many SSSI sites were de-notified, removing them from the SSSI classification protection. To continue protection of these special geological sites the RIGS designation was developed.

RIGS locations are designated by locally developed criteria. The sites are selected and designated according to their value for:

• educational fieldwork in primary and secondary schools, undergraduate level and adult education courses,
• scientific study by both postgraduates, professional and amateur earth scientists,
• historical significance in terms of earth science knowledge and local heritage value,
• aesthetic value of the landscape.

If a site is of geologic or geomorphic interest and meets one or more of the RIGS criteria then it can be put forward for designation with the local authorities in order to be recognised and protected. It is worth noting that not all geodiversity can be protected and designated as RIGS status but that is not to say that it has no value, it just doesn’t meet the standard for RIGS designation. Geodiversity is around us everywhere and it would be impractical to designate the whole surface of the earth as a RIGS location so RIGS groups have to be selective.

Why do we need RIGS designation?

Most RIGS have been overlooked in the Tees Valley. RIGS locations are at risk from a variety of activities including:

• landfill projects
• inappropriate or poorly planned reclamation schemes
• housing/industrial developments
• ignorance/neglect

Geodiversity is a fragile, finite and unique snapshot of another time which, once destroyed, cannot be recreated. Tees Valley RIGS group works closely with the Tees Valley Wildlife trust, especially the original Geodiversity Office Andrew Carter and the new Natural Heritage Awareness Officer Beth Addis. Since its formation in 2003 85 sites have been surveyed and 35 have been given RIGS designations. The Tees Valley RIGS group consists of dedicated local volunteers from a wide range of backgrounds interested in preserving our geological and geomorphic heritage. The group consists of regular volunteers coming from local geological associations, local aggregates industries, education and the general public. As well as surveying the whole area the RIGS group have created six interpretation boards for some of our most recognisable features including Roseberry Topping and Hunt Cliff in Saltburn.

The RIGS group have played an integral part in the creation of the Tees Valley Geodiversity Action Plan.

[[[IMM-Glossary]]]

The Quaternary period is the shortest division of time in the geological column covering only the last two million years or so of Earth’s history. It can be divided into four major phases of ice-sheet advance, (glacial), and retreat (interglacial). Many smaller cycles of advance and retreat occur within each major phase. The Quaternary can be divided into two stages, the Pleistocene - which covers all deposits between two million and ten thousand years ago, and the Holocene - encompassing deposits from ten thousand years ago to the present day.

Devensian

The most recent ice sheets to occupy the Tees Valley were during the Devensian stage when ice advanced on the area from the Lake District and Scotland in the north. Pressure from Scandinavian ice in the North Sea Basin also affected conditions locally by forcing the Scottish ice stream inland at Saltburn and Staithes.

Some landforms, such as Freeborough Hill, were sculpted as the ice-sheets carved up the original landscape as they advanced. Others, such as Cat Nab at Saltburn, resulted as the ice melted and the material it had picked up en route was dumped. Immense amounts of melt water; unable to escape in any other direction, flowed along the ice margins forming temporary lakes where the landscape allowed. Longer-lived water bodies tended to fill until they eventually overflowed, the escaping streams often cut distinctive channels which were abandoned as flow rates diminished.

The most extensive evidence of former occupation by ice-sheets are the thick deposits of boulder clay that cloak the landscape, softening its contours to heights of between 250 and 300 metres above sea level. This material has also in-filled some of the pre-Devensian features producing buried valleys, most notably at Upgang and Saltwick Bay, near Whitby.

In contrast to its later dominance, the chemical industry made a rather tentative appearance on Teesside, encouraged by the area’s transport network. Its establishment can possibly be attributed to Robert Wilson of Yarm who founded the Egglescliffe Chemical Company at Urlay Nook, adjacent to the Stockton and Darlington Railway in 1833. The firm specialized in the synthesis of sulphuric acid, which they employed in the production of fertilizer. Continuing to serve the agricultural trade, the Egglescliffe Chemical Company expanded in 1865 to include linseed oil and cake mills.

Processes connected with the iron trade produced noxious gases that happen to contain useful chemicals and Bell Bros led the way in their recovery by extracting coal tar from their coke emissions. In 1868, Sadler and Co. established works at Cargo Fleet for the distillation of this tar, becoming the first to extract and market benzene.

Much of the chemical industry relied upon huge deposits of evaporites (sediments formed by the evaporation of saline water). These were laid down during the Permian Period about 250 million years ago around the margins of the Zechstein Sea, which then stretched from Yorkshire eastwards across much of northern Europe. Subsequently, the deposits were deeply buried under thousands of metres of sediments including the Jurassic rocks that form the present land surface. The evaporites include halite (rock or common salt, sodium chloride), potash (sylvite, potassium chloride) and anhydrite (calcium sulphate), all three of which have been utilised.

Salt

An unexpected offshoot of the iron trade came as the result of profiteering on the part of the Darlington water company whose prices rose steadily in the early 1860’s. Bolckow, Vaughn and Co. made a borehole at their Vulcan Street works in an attempt to secure a free water supply of their own but rather than water it revealed the presence of a bed of salt 100ft thick (30m) at a depth of 1,300 feet (396m). They tried to sink a shaft to the deposit but constant flooding meant it was eventually abandoned. A decade passed before Bell Bros., at their Port Clarence works, located the same bed at a depth of 1100 ft (335m) and again flooding meant they had to abandon the task. In 1882 the introduction of the hydraulic method of salt extraction from Alsace in France, meant they could now extract the salt. Fresh water was pumped down boreholes and the resulting brine extracted. It was then evaporated to collect the salt. Bell Bros. were the first to respond, quickly followed by Bolckow, Vaughan and Co, Pease and Partners and the Cleveland Salt Company. By the mid 1890s production amounted to 300 000 tons per annum, the majority of which was shipped to Tyneside for the alkali industry. An interesting development came in 1890 when Mr. Weddell began selling salt in a packet form, one of the first to do so. This was the beginning of Cerebos, which later became virtually a brand name for salt. In 1906 he began a factory at Greatham, which subsequently added BISTO, a new gravy powder to their list of products. Eventually the industry extended along both sides of the river. Extraction ceased in 1971 but it had resulted in the formation of huge underground cavities. Some of these are used for storage of gases, and lately applications have been made to utilise others for the storage of hazardous waste.

The principal uses of sodium carbonate are in the manufacture of glass and the production of chemicals. It is also used in processing wood pulp to make paper, in making soaps and detergents, in refining aluminium and in water softening.

Anhydrite (anhydrous calcium sulphate) formed in the same way was mined at Hartlepool and Billingham and was used for the production of ammonium sulphate, which is used as an artificial fertiliser and in the production of explosives.

Potash

The deposits are mined today at Boulby near Staithes. There are two 1150m deep shafts put down to develop a seam of potash about 7.5m in thickness and with an average grade of 35% potassium chloride. Production commenced in 1973 and is currently about 1 million tonnes per year of potash for use in the chemical and agricultural industries. In addition, large amounts of rock salt co-product are mined and mainly used for gritting roads.

The geology of the Tees Valley, as well as by-products from its former industries, have both provided construction materials used locally and elsewhere. Building stone, clay for brick making, and road-stone have all been exploited at one time or another.

Building Stone

The earliest constructions using locally derived stone are the estimated 10,000 burial mounds erected by the area’s Neolithic inhabitants from around 4,000 years ago. These ancient builders appear not to have quarried, but rather gathered up the many boulders of Middle Jurassic and Quaternary age that are scattered across high ground. Quarrying for building material allegedly arrived in Britain with the Romans, though no workings of this age exist in the Tees Valley.

Permian

The buff coloured, fine grained Lower and Middle Magnesian Limestones provide the only viable building material from the Permian Period. Medieval masons used it because it was easy to carve intricately. It was used in the construction of many Abbeys and Minsters, including York Minster.

Jurassic

Perhaps the best locally available building material is the massively bedded deltaic sandstones of the Middle Jurassic. Disused quarries in the Saltwick Formation can be found on hills around Eston, Upleatham, and Skelton in addition to the escarpment of the Cleveland Hills and North York Moors. Prestigious buildings, like Guisborough Priory, as well as alum works, mine buildings, cottages, railway bridges, stations and field walls have all, in the past, been constructed using this stone. Quarries at Galley Hill, near Aislaby (N. Yorks.), provided large blocks for Whitby’s East Pier, not to mention foundations for the original London and Waterloo Bridges. Blocks of Dogger Formation sandstone from near Whitby were used to construct breakwaters and loading ramps at Saltwick alum works.

The Lower Jurassic strata are not renowned for their building materials, though they have occasionally been used for this purpose. Flags from the finely laminated Staithes Formation provide paving slabs for several coastal villages including Staithes and Runswick. In 1861, local ironmaster John Bell built Rushpool Hall near Saltburn using ironstone mined from Cleveland’s first shaft mine at Skelton. A wide range of fossils can be seen in its slowly weathering walls.

Tertiary

Whinstone setts were occasionally used for building. They can be seen forming a decorative base on the town clock at Redcar.

Bricks

Brick making is perhaps more commonly practiced in regions without a viable source of good building stone. These are, by definition, districts generally underlain by fine-grained deposits suitable for the manufacture of bricks. Despite the ready availability of building stone in the Tees Valley, the areas rapid expansion in the mid-1800s was primarily achieved using brick, which is cheaper and more convenient than quarried stone. Triassic and Jurassic shales and mudstones, in addition to superficial drift deposits, have all been exploited for this.

At Commondale, mudstones from the Saltwick Formation were extensively quarried and milled into clay to produce brick and tile.

Brickworks on the Tees floodplain used the glacial clays to produce bricks and tiles.

A brickworks existed at Skinningrove to produce building materials from the glacial clay. The bricks were used to line drifts in the mine.

Slag from iron and steel making was cast into grey-blue bricks used to construct many miles of training walls to tame the River Tees, and which commonly line gutters in towns and villages across the area.

Road Stone

An ironstone quarry on Eston Hills provided road stone until 1850, when it was found that would be used to launch the iron and steel industry on Teesside. Another, more durable, source of road stone can be obtained from the Cleveland Dyke. Many quarries and mines were opened to extract it for use in highways across the north of England. Perhaps the best remains are to be found at Cliff Rigg, near Great Ayton, where quarrying and mining occurred between 1869 and the 1930s. Others can be found at Preston Park, Ingleby Barwick, and numerous sites across the North York Moors.

The history of local ironstone mining and the development of the Tees Valley are intimately linked.

The history of Ironworking

The earliest smelting of ironstone in the area is traceable to c.400BC and the Iron Age. Later, in the 1200s, there is evidence of furnaces in Eskdale, at places such as Fryupdale and Egton. Heaps of furnace slag around Rievaulx Abbey marks the working of local ironstone by monks, a trade that continued until the mid-1600s. Evidence is then scant for around a century until we learn that nodules and boulders of ironstone were collected in summer from the scars by local coastal communities. The ironstone was loaded onto small boats grounded on the rocks nearby, before travelling to furnaces on Tyneside. Such seasonal work provided a welcome financial boost for villagers who usually relied upon fishing to survive. Ironstone collected at Robin Hood’s Bay fed the Whitehill Furnace, founded at Chester-Le-Street in 1745, for around fifty years, and the Tyne Iron Company obtained their stone from various scars between Saltburn and Scarborough until the mid-1800s.

Quarrying began in the late-1820s where the ironstone crops out on the foreshore at Kettleness, and later in Brackenberry Wyke east of Staithes. In 1835, a Mr. Wilson (partner in Losh, Wilson, & Bell – ironmasters on Tyneside) noticed ironstone in a cutting at Grosmont whist inspecting construction of the Whitby and Pickering Railway. Drift mines were soon operating with the stone going by rail to Whitby. Cleveland ore still travelled by sea to Wearside and Tyneside for processing, but all of this was soon to change.

When Bolckow and Vaughan sought a local source of iron for their furnaces in the new town of Middlesbrough, the Cleveland ironstone was the obvious choice. The opening of a drift mine at Skinningrove in 1848 spurred him on and, with the help of mining engineer John Marley, the quest moved North West to Eston. On 8th June 1850, the pair located a quarry from which road stone had been extracted for some years. On inspecting it, they found that the rock in question was the Main Seam of the Cleveland Ironstone Formation, which here lay some sixteen feet (4.8 metres) thick.

Bolckow and Vaughan’s success was soon being felt by other mining companies as the extent of the ironstone underlying Cleveland became clear.

Soon, shaft mines joined an expanding number of drift mines as the railway made its way into East Cleveland where the ore lies at depths up to 720 feet (220 metres). In 1881, Middlesbrough celebrated its jubilee and the miners in the Cleveland Hills responded with a total production of above six million tons – double the projected output – over a million tons from Eston alone.

The Iron Smelting Process

Ironstone arrived on Teesside by rail where it was initially placed in kilns, with coal or coke, to be strongly heated (calcined); this had the effect of driving off water and some of the unwanted sulphur resulting a concentration of the iron content from 33% in the raw stone, to 40%. Next, the ore was placed in a blast furnace and smelted, with the resulting iron being cast into ingots known as pigs. These would be later re-melted in a puddling furnace and the iron stirred to remove excess carbon making it malleable.

A major by-product of smelting was furnace slag, the disposal of which proved a costly affair for the ironmasters who were forced to rent land upon which to store it. The solution to this problem arose as the result of improvements along the banks of the Tees. Some slag, from the stockpiles along the River, was taken for reclamation schemes and the ironmasters would even pay four pence per ton for its removal. Slag was also cast into bricks in order to construct 22 miles of strong training walls to channel the River more efficiently. More recently, the North and South Gare breakwaters at Teesmouth are constructed upon foundations comprising millions of tons of furnace slag. Other by-products were utilised by the area’s growing chemical industry.

The discovery of a new method of the steel production (the Bessemer process) in the 1850s, which worked better using non-phosphoric ores unlike those available in Cleveland, could have been an early problem. John Vaughan, who engaged the help of two colleagues from Staffordshire to look at the problem, overcame it. They eventually contrived the successful Thomas-Gilchrist process, by which local stone could be processed into high-grade steel for world markets. This process is still used today in other parts of the world.

The industry’s decline was long and drawn out, commencing at the end of the nineteenth century, with the intervention of two World Wars which kept Cleveland stone flowing from the hills. After the second War, the tenacity and skill of Cleveland miners and ironworkers ensured that the industry might fade, but would never die in this proud region. Despite everything, mining of Cleveland Ironstone finally succumbed in 1964 with closure of the deepest, and last, of over eighty mines in the ore-field at North Skelton. Amongst the hills of Cleveland, which once resounded to the sound of steam-powered industry, stand the tumbled-down remains of these once great mines. Their ruins, today being gradually reclaimed by Nature, resound only to the gentle sounds of birdsong. However, their presence, in addition to the blast furnace at Redcar, works at Skinningrove, and the foundry at Guisborough all bear testament to the region’s rich industrial past.

Alum Shale

The Alum Shale Member forms the upper part of the Whitby Mudstone Formation and was deposited in a reasonably well oxygenated marine environment around 186 million years ago.

The shales were extensively quarried between 1604 and 1871 for the alum trade that flourished only on the coast and hills of the Cleveland and North Yorkshire. The quarrymen would choose shales that contained the fossil bivalve Nuculana ovum (accompanying fossil) knowing that these were depleted in calcium carbonate but still contained pyrite. Calcium Carbonate would negate the effect of sulphuric acid formed by breakdown of pyrite during the alum making process and ruin the finished product.

The Alum Trade

The alum trade came to the Cleveland hills between 1600 –1608. The location of this once strategically important industry is restricted to this part of the country because of the occurrence of the alum shale required to produce it. The alum trade lasted for over 260 years before the final alum works in the area closed at Sandsend in 1871.

What is Alum?

Alum is a useful substance, used as a mordant (fixative) when dyeing cloth as well as being employed in tanning leather. It still is a vital chemical in many developing and industrial societies.

Once it was essential and scarce. Long before it could to be manufactured in Britain, ancient Chinese and Arabic cultures employed alum as a key ingredient in alchemy and magic, in addition to other uses, i.e. as a remedy for toothache, in an elixir of life with mercury and cinnabar, and as an ingredient in the many attempts at turning base metals into gold. For these reasons, the processes involved in making alum remained a closely guarded secret.

By 1459, alum production was under the control of the Papal States. By the time of the reformation and the beginnings of Protestantism, Britain’s supply was in jeopardy and a secure source was required prompting a number of searches.

The man responsible for bringing the alum makers secret to Britain was a North Country gentleman called Sir Thomas Chaloner. Whist touring Europe he visited the Papal alum works at Civitaveccia in Italy, where he found that the rocks there were very similar to those on his land back home in England. In order for him to produce alum he needed more information, so he persuaded two alum workers to escape with him. This was a very dangerous undertaking and legend has it that he smuggled them onto his ship in barrels and sailed away before they were missed. When the Pope realised that his monopoly of supplying alum to the whole of Western Europe was in jeopardy he excommunicated Chaloner before cursing the man, his family, and its future generations.

When Chaloner returned to England, he spent a number of years experimenting at Belman Bank, near Guisborough, before producing useful alum. Once this was accomplished, he was ready to start Britain’s first commercially important chemical industry. As the value of the local alum shales was realised the secret of alum making spread as landowners with the shale on their estates began to cash in on their good fortune. This development transformed parts of the once quiet coast line and hills into industrial areas.

The Secret of Alum Making

The process required to make alum can be broken down into a series of stages:

• Quarry the shale and build it up onto heaps up to 10 metres high and 50 metres long (known as clamps) with brushwood interleaved. Up to 100 tons of shale is required for each ton of alum produced meaning that 99% of the material quarried ended up as waste! The distinctive pink or orange calcined waste still washes up on many beaches in the area.
• After quarrying, the enormous heaps were set on fire in order to start a complex series of chemical reactions. This part of the process (calcining) produced sulphuric acid that helped break down the minerals within the parent rock. The clamps often burned for months before the next step.
• The clamps were then broken open and clean water was poured through them. This dissolved the sulphates, the part used in alum making, leaving some of the impurities behind. The resulting liquor (Mother’s) was allowed to settle before being channelled into a nearby alum house for evaporation.
• Next, the alum makers would add either potash, acquired by burning seaweed, or ammonia in the form of urine. Barrels of urine arrived from Sunderland, Hull, London, Newcastle, and other cities in boats specially adapted for landing on the rocky scars beneath the cliffs. The ships would later leave carrying alum in the self-same barrels.
• There was one last problem to overcome. The alum was in solution with unwanted ferrous sulphate and a worthless product would result unless the alum could be isolated. Separation is a relatively simple exercise, namely boil the liquid to drive off some of the water and at some point alum will crystallise out of the solution. The problem was that very soon after this point the ferrous sulphate would also crystallise out ruining the batch.
• The alum makers needed a reliable way of indicating at what stage of evaporation the liquor had reached in order to identify the critical point at which the alum was ready. This knowledge was the alum makers secret.
• The answer they found is as ingenious as it is simple. As any salt crystallises out of solution, the density of the liquid varies. What the alum makers required was a way of monitoring the change so that at the right moment, the liquid containing the unwanted ferrous sulphate could be drained off leaving pure alum. Who found the answer no one knows, but in the years between 1600 and 1608, the secret of monitoring this process at last came to light and proved to be as ingenious as it was simple. A fresh hen’s egg placed in the evaporating liquor would initially sink, but as evaporation proceeded and the specific gravity of the liquor changed, then the egg would suddenly begin to float. What’s more, this phenomenon would occur at precisely the same time as the alum crystallised out –

EUREKA!

Alum working might still be carried out here if aniline dyes and a synthetic method of sulphuric acid production had not been discovered in the 1800s. Following the latter discovery, alum could be made using colliery waste thereby doing away with the vast quarries required in the past. These discoveries led to the decline and ultimate demise of alum making on the coast and in the hills of Cleveland and North Yorkshire.

The much-prized mineral known as jet, commonly associated with Whitby, is present across much of the Tees Valley and North Yorkshire. The name jet comes from the Greek term for jet ‘Lithos Gagates’ which means stone of Gagas (Gagas is a town in Turkey). In French this translates into gaiet or jaiet and then into English as jet.

The earliest examples of worked jet date from around 10,000BC. Since the Bronze Age, people in Yorkshire have seen jet as a valuable commodity, often recovered from burial mounds (barrows) in the form of beads, bracelets and other precious items. Jet became universally popular when in 1861, Albert, Prince Consort to Queen Victoria died. Queen Victoria entered a long period of mourning declaring only jet jewellery was to be worn in court. The jet industry responded and by 1872, it is estimated that there were around 200 workshops, with over 1400 people employed to turn the raw material into beautiful jewellery. This is compared to 2 jet workshops employing 25 people in 1832.

Jet formed from the fossilised trunks of Araucaria trees - similar to the modern day Monkey Puzzle. The trees grew on a Jurassic landmass away to the north west, a little over 180 million years ago. When they died and fell in the river they were carried to the ancient sea. The trunks would eventually become waterlogged and sink to an oxygen-poor sea floor where decomposition was either slow or non-existent. Gradually, the sunken logs became buried beneath more sediment until their once rounded trunks were flattened into thin planks by the weight. The rock member in which jet resides belongs to the Whitby Mudstone Formation and is known as the Jet Rock. The mineral comes in two forms known as hard or soft jet, with the former most prized for working and found below a thin limestone known as the Top Jet Dogger. Soft jet can be found slightly above the Top Jet Dogger as well as in the deltaic deposits of the Middle Jurassic. Native jet often preserves the shape and texture of the tree that made it and this can sometimes be seen in the finished jewellery.

When it is found, it is a dull grey brown and unspectacular to look at, but it is easily worked and after final polishing jet takes on a deep lustrous shine.

In the early days of exploitation, jet was simply picked off the beaches, but as demand grew mining became necessary. Dessing is an early method of working jet. It involved a man being lowered over the cliff side where he would break off pieces of jet. As demand grew, safer methods were sought to get the jet and mining started. Whitby was the main manufacturing centre but much of the jet was obtained from small mines located along our part of the coast and inland, for example in the hills around Guisborough and Great Ayton. Jet was usually mined by driving tunnels, known as adits, into the cliffs or hillsides, several metres below the Top Jet Dogger. The miners would then work into the roof, standing on the spoil they produced to reach the ceiling as the roof gained in height, until they met the Top Jet Dogger which they used as a strong roof for their workings. The miners sold the jet they collected to a jet merchant who would then sell it on to a jet workshop where they would turn it in to jewellery.

How to identify jet

1. Look for evidence that jet was once a tree - sometimes growth rings can be seen.
2. Jet will leave a brown mark when scratched on a piece of unglazed white pottery.
3. If you burn jet it will smell like burning coal.
4. Jet is warm to the touch.
5. Jet will never fade in sunlight.

Discover the hidden gems in an old sand and gravel quarry near Norton in Stockton - on - Tees. This quarry has been in-filled and is now owned by the Tees Valley Wildlife Trust who manage it for its fantastic orchids that can be seen in early summer.

The walk

To get to the reserve you will need to cross a busy railway but once inside it is a self contained gem. The walk is only 1 mile (1.5 km) and has interesting features at anytime but it really comes alive in June and July.

Gravel Hole Geotrail

Geotrail Extra

If you want to know a bit more about the Gravel Hole Geotrail then these pages will give you lots of background information and useful links.

On each Geotrail you will see a little symbol ? which lets you know that there is more information about that subject here.

Gravel Hole Geotrail Extra

The Audio files

If you want to use an mp3 player instead of the trail guide and still have a guided walk then these are the trails for you. The routes are the same as the Geotrails but it is more like having your own guide and much less formal and more descriptive.

 

 Gravel Hole Geo-Trail (mp3 version): Play Now | Play in Popup | Download

 

 Gravel Hole Geo-Trail (m4a version): Play Now | Play in Popup | Download

Access Trail

If you would like more information about the route of the Gravel Hole Geotrail then this map highlights steps, slopes, stiles and cliffs along with any hazards on the way.

GPS Trail

If you have a GPS and memory map software then you can download the trail here and use your GPS to navigate your way around.

Gravel Hole GPS Trail

This large quarry on the slopes of Roseberry Topping is the nearest we have to a volcano in the Tees Valley.

The Cliff Rigg Geotrail guides you around this quarry giving you a glimpse into its past from its volcanic beginnings to its busy industrial extraction.

The walk

The geology in this walk is a little bit more complex and the walk goes near some steep drops, not for the faint hearted. The walk starts in Great Ayton and is 3 miles (5 km) and will take about 3 hours.

Cliff Rigg Geotrail

Cliff Rigg from a higher perspective.

Geotrail Extra

If you want to know a bit more about the Cliff Rigg Geotrail then these pages will give you lots of background information and useful links.
On each Geotrail you will see a little symbol ? which lets you know that there is more information about that subject here.

Cliff Rigg Geotrail Extra

The Audio files

If you want to use an mp3 player instead of the trail guide and still have a guided walk then these are the trails for you. The routes are the same as the Geotrails but it is more like having your own guide and much less formal and more descriptive.

 

 Cliff Rigg Geo-Trail (mp3 version): Play Now | Play in Popup | Download

 

 Cliff Rigg Geo-Trail (m4a version): Play Now | Play in Popup | Download

Access Trail

If you would like more information about the route of the Cliff Rigg Geotrail then this map highlights steps, slopes, stiles and cliffs along with any hazards on the way.

Cliff Rigg from a lower perspective.

Roseberry Topping is a historical landmark for the Tees Valley situated on the edge of the North York Moors National Park and owned by the National Trust.

The walk

The Roseberry Topping Geotrail is a walk to the top of this well known peak learning about its hidden past along the way.

The walk is about 2.5 miles (4 km) and will take 2-3 hours.

Roseberry Topping Geotrail

Geotrail Extra

If you want to know a bit more about the Roseberry Topping Geotrail then these pages will give you lots of background information and useful links.
On each Geotrail you will see a little symbol ? which lets you know that there is more information about that subject here.

Roseberry Topping Geotrail Extra

The Audio files

If you want to use an mp3 player instead of the trail guide and still have a guided walk then these are the trails for you. The routes are the same as the Geotrails but it is more like having your own guide and much less formal and more descriptive.

 

 Roseberry Topping Geo-Trail (mp3 version): Play Now | Play in Popup | Download

 

 Roseberry Topping Geo-Trail (m4a version): Play Now | Play in Popup | Download

Access Trail

If you would like more information about the route of the Roseberry Topping Geotrail then this map highlights steps, slopes, stiles and cliffs along with any hazards on the way.

This walk around the gently undulating magnesian limestone country near Hartlepool in the north of the Tees Valley looks at rocks created in a shallow tropical sea. The story continues through the cold ice ages and into the industrious middle ages.

The walk

The walk is about 4.5 miles (7.5km) and takes about 3 hours. It crosses 2 fords so make sure you have your wellies.

Hart Village Geotrail

The Audio files

If you want to use an mp3 player instead of the trail guide and still have a guided walk then these are the trails for you. The routes are the same as the Geotrails but it is more like having your own guide and much less formal and more descriptive.

 

 Hart Village Geo-Trail (mp3 version): Play Now | Play in Popup | Download

 

 Hart Village Geo-Trail (m4a version): Play Now | Play in Popup | Download

Access Trails

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The Tertiary period began sixty-five million years ago with fire, and ended only two million years ago in ice. It opened with a meteorite about the size of the Tees Valley, slamming into the Earth with unimaginable force near to where Mexico lies today. This catastrophic event dealt the final blow to a now-declining population of dinosaurs, along with other Mesozoic creatures such as ammonites and belemnites. It ended when a large part of the Northern Hemisphere was overwhelmed by advancing glaciers at the onset of the Ice Ages.

No sedimentary rocks of this age exist locally today, but the Tees Valley’s only igneous rock, the Cleveland Dyke, formed during the Tertiary period some fifty-eight million years ago. Intense volcanic activity along the west coast of Scotland ended with the earth’s crust being stretched as the Atlantic Ocean grew between the continents of North America and Europe. Magma was injected into fissures deep under the surface, which, on cooling, formed dykes that can today be found at, or close to, the surface. One of these extends all the way from the Isle of Mull to Teesside. The magma formed a durable, blue-grey rock known as whinstone much used for road metal and cobbles. It was extensively quarried and mined between 1869 and the 1930s at Cliff Rigg, near Great Ayton, as well as Preston-on-Tees, Ingleby Barwick, and numerous places on the North York Moors.

The Tertiary period also saw evolution of human ancestors including Homo habilis, the first tool user, around three-and-a-half million years ago. True humans, like you or I, did not appear until a mere one hundred-and-fifty thousand years ago, and geology as a science is said not have really got going until the late 1700s. However, could it be that their expertise in the use of simple stone tools made these primitive ancestors the world’s first real geologists?

On the south bank of the Tees, near Warrenby, a change occurs in the rocks below ground that leaves no trace on the surface. It is a transition from almost lifeless Triassic mudstones, to beds packed with the fossils of creatures that lived in the most notorious period in Earth’s History – the Jurassic! Stretching along the coast from Redcar to Filey can be found a sequence of rocks that have been highly acclaimed by generations of geologists:

“In no part of England is the relation of the surface topography to the nature of the underlying rocks more instructively displayed than in this district; nor can the succession of a considerable part of the Jurassic series of formation be anywhere more advantageously examined than along the coast-sections…”
[Archibald Geikie, Director of the Geological Survey. (1888)]

Jurassic deposits locally total around 560 metres of strata, and have been broadly classed into Lower, Middle, and Upper divisions. This strata was deposited between 204 and 158 million years ago in environments that ranged from deep sea populated by a variety of distinctive marine creatures, to well-vegetated river delta upon which dinosaurs once roamed.

Geologists long-ago realised that similar rocks in diverse areas could be correlated by examining their fossil content. One of the earliest to realise this was Louis Hunton (1814-1838), son of a Loftus alum-worker who studied remains of long extinct sea creatures in Jurassic rocks at Hummersea. As far as correlation of different rock units is concerned, the most useful fossils turned out to be the coiled shells of many species of ammonites,. Ammonites are an extinct creature related to modern day squid and octopuses. Modern geologists can identify over sixty ammonite zones, which finely subdivide the various strata and make relationships between them much easier to understand.

Lower Jurassic

Lower Jurassic rocks were deposited in a variety of marine environments ranging from shallow sea floor to deep sea. The shallow sea floor probably underwent brief periods of emergence and erosion. The deep sea had abundant plankton in the upper waters but an oxygen-depleted floor.

Redcar Mudstone Formation

After the noxious conditions of the Triassic incursions, the sea deepened, became fully oxygenated, and a new era of sedimentation commenced with the Redcar Mudstone Formation. The rock outcrops on the coast between Redcar and Staithes, and is perhaps most notable for the great number of fossil oysters (‘Devil’s Toe-Nails’) that wash up on the beaches nearby. At its base are cycles of soft mudstones capped by thin, hard limestones often packed with well-preserved fossils and best seen on the scar at Redcar.

Staithes Formation

During deposition of the preceding Redcar Mudstone, waters became ever shallower causing a change in the type of sediment laid down on the sea floor. The Staithes Formation comprises fine-grained sandstones, thin mudstones, and bands of iron rich nodules. Finely laminated sandstones, up to 0.8 metres thick, are frequently followed by units in which the bedding has been completely wiped out when increased wave action during storm surges churned up the sea floor. The Staithes Formation is possibly the most fossiliferous rock to be found locally, with extensive shell beds, belemnites, trace fossils left by many creatures that burrowed within the sediments, and much more. Sedimentary structures such as ancient ripple marks are also commonly seen amongst these rocks.

Cleveland Ironstone Formation

This is famous for the part it played in the growth of Teesside. The beds belonging to this formation formed in conditions of varying sea level. They are made up of layers of grey silty mudstones and, five distinct seams of ironstone, the latter deposited during shallower episodes, in a sea rich with life. Fossils are common and well preserved in the ironstones. The seams increase in both thickness and grade upwards culminating in the Main Seam which possesses an iron content of thirty-three percent and maximum thickness of 4.8 metres. Cleveland ironstone has an oolitic texture and is blue-grey or olive-green in colour when fresh, weathering to a rusty red-brown.

Whitby Mudstone Formation

After deposition of the Cleveland Ironstone, the sea reached depths not experienced across the area since Permian times. The change was gradual and there is little difference between the Grey Shales at the mudstone base, to those of the preceding formation. Following the Grey Shales is the Jet Rock, comprising beds of dark finely laminated shale containing pyrite. The pyrite smells strongly of mineral oil when freshly broken. Seasonal falls of dead plankton from the upper waters are responsible for the presence of oil. Seams of jet are found where waterlogged tree trunks became buried within the oxygen-depleted sea floor mud. The sequence ends with a thin limestone known as the Top Jet Dogger.

Shallower seas led to greater oxygenation of the waters and deposition of beds known as alum shale. Many large marine reptiles (plesiosaurs, ichthyosaurs, and crocodiles) have been recovered from these beds some of which are displayed locally. The Whitby Mudstone Formation usually finishes with the Cement Shales. These differ little in appearance from the alum shales, but contain numerous large limestone nodules once processed for hydraulic cement.

Middle Jurassic

The late Lower Jurassic experienced the deepest seas since the Permian Period. Transition to the Middle Jurassic saw extensive uplift of the local strata which allowed a river delta to encroach upon the area from the north and west. The sea twice covered the delta and associated marsh, resulting in cycles of deltaic and marine sedimentation, known collectively as the Ravenscar Group.

Dogger Formation

At the base of the Middle Jurassic, the area was gently folded into a series of low domes and basins, producing a mosaic of depositional environments. Parts of the former sea floor emerged above the water to be weathered and eroded. The sediment became generally coarser due to the closer proximity of land, and was inhabited by a diverse fauna of invertebrates and other marine creatures. Accordingly, the Dogger Formation displays a number of different rock types, (sandstone, mudstone, siltstone, sandstone, and ironstone), that vary across the area. These are often packed with fossilised burrows. The formation rarely attains a thickness in excess of a few metres and in places is absent altogether.

Saltwick Formation

As uplift progressed, so the deposits change to thickly bedded yellow sandstones, grey siltstones, and some minor mudstones. This change occurred as a great river delta advanced across the former sea floor. Within the Saltwick Formation can be found beds of fossil wood, some of which form seams of jet, indicating that the delta was well vegetated. In fact, the earliest fossil of a flowering plant (Weltrechsia whitbiensis) was recovered from beds in this formation near Whitby. Perhaps the most sought after, and least found fossils, are those of dinosaur footprints. These tell us that land-dwelling reptiles of many species once browsed and hunted on the delta-marsh.

Eller Beck Formation

This is a thin sequence deposited when the sea briefly covered the delta from the southeast. It laid down a basal bed of mudstone with marine fossils, which is replaced higher up (in places) by a thin or nodular ironstone, and lastly a sandstone. The presence of Ooids within some of the iron nodules indicate a shallow tropical environment.

Cloughton Formation

Renewed uplift of the crust once again banished the sea and the area continued to be under a deltaic regime. The Cloughton Formation is much more variable than the Saltwick, though it retains a very similar set of fossils. The imprints of delicate ferns and horsetails can be found amongst the beds of sandstone, siltstone, and mudstone. It also bears the imprints of reptilian feet at various levels.

Scarborough Formation

A second incursion of the sea deposited sandy limestone packed with marine fossils. This is generally a blue-grey rock containing the fossils of belemnites, shellfish, scattered wood fragments, and sea-lily stems. The formation attains a thickness of around 5 metres locally, though is seldom well exposed at the surface.

Scalby Formation

A return to deltaic conditions is marked by the Scalby Formation. The lower 10 metres consists of high-grade sandstone known as the Moor Grit with a quartz content as high as 98.15%. It contains few fossils except for the occasional wood fragment. Above it lays the Long Nab Member marking a return to the delta-marsh conditions of the Saltwick and Cloughton Formations. Further south are extensive plant beds, but in the Tees Valley, it comprises flaggy sandstones with intermittent mudstones deposited during periods of flood.

Upper Jurassic

The deltaic regime ended with deposition of the Scalby Formation at the top of the Middle Jurassic. Marine deposits above it are assigned to the Upper Jurassic and are rare in the Tees Valley. Only on the higher parts of the moors in East Cleveland can these rocks be found. The lowest beds belong to the Cornbrash, in other localities it exists as a limestone, but here it is brown sandstone with the imprints of numerous shellfish. Attaining a thickness of only about 5 metres, the Cornbrash is quickly succeeded by the Osgodby Formation. Up to 30 meters of this rock can be found in the south of the region, locally though it only reaches around 5 metres. Fossils of many kinds are abundant in the beds of blue-green sandstone that are only rarely exposed.

The Triassic Period started around 225 million years ago. It marks the extinction of creatures such as trilobites, the continued development of reptiles, and first appearance of small mammals in the fossil record. This change in fauna marks an important transition between Palaeozoic (ancient life) and Mesozoic (middle life) Eras of life on Earth.

Sherwood Sandstone Group

During the Late Permian and Early Triassic this area was an arid coastal plain. It was subject to rapid deposition of sediment carried by flash floods flowing from the Mercia Highlands (in the Midlands) to the south. Adjacent to the base of the uplands, thick pebble beds developed as the descending water dumped the heavier material it carried as it flowed onto flatter ground. Lighter particles of sediment, sand and mud, were spread in great fans away from the uplands across the flat plain, and it is these that make up the Sherwood Sandstone Group in our region. Alternating beds of yellow or red sandstones and thin mudstones typify the rock unit, which underwent various episodes of both deposition and erosion. It has a distinct lack of fossils, partly because of the harsh environment but also because life on earth appeared to be still recovering in numbers from the Permian Mass Extinction. An erosion surface (unconformity) marks the top of the Group.

Mercia Mudstone Group

The next episode in the area’s development saw a shallow sea advance across the coastal plain as an intermittent marine connection opened to the southeast. Circulation of water within this sea was restricted and it frequently cut off from the main water body. When it was isolated there was evaporation which then concentrated the dissolved salts. Saline lagoons, pools of hot mud, and glittering beds of salt developed. As a result, the Mercia Mudstone Formation is comprised of beds of dark brown or blue mudstone, frequently mottled. The Mercia Mudstone Formation was formed from the fine-grained material washed or blown into the sea from the flat plain. The mudstones alternate with occasional evaporites including halite, gypsum, and anhydrite.

Penarth Group

The sea readvanced. The Penarth Group was deposited over about 30 million years. The highly poisonous salt surface, over which the sea advanced, combined with restricted circulation of its waters, produced considerable variations in salinity and oxygen content at first. The lack of oxygen formed the black sulphurous shales in the lower part. In this layer a bone bed indicates mass mortality of many creatures, this is believed to have been caused by algal blooms.

As the sea deepened marine creatures of many kinds began to flourish. Consequently, higher in the Penarth Group succession, and hence later in time, lie brown and green mudstones containing the fossils of shelly creatures. Indicating life beginning to establish itself locally in the improving waters.

Triassic rocks crop out at very few localities in the Tees Valley making any exposure all the more valuable. However, an example of Sherwood Sandstone can be seen at Little Scar, Seaton Carew when the tide is out, and Mercia Mudstone can be found along the River Leven downstream of Hutton Rudby.

Earth movements during the preceding Carboniferous Period gradually raised the land’s surface across much of the UK in what is known as the Hercynian Orogeny. This event raised the Harz Mountains in Germany, and further north the Mercia Highlands that once extended from Devon to the Wash. Former areas of well-vegetated tropical delta-marsh, within which the commercially important Coal Measures developed, became buried as a hot arid desert advanced across the area. It was under these conditions that the oldest rocks to crop out within the Tees Valley were laid down between 290 and 245 million years ago during the Permian Period.

Lower Permian

The lowest, and hence oldest, beds in the succession locally are a mixture of dune-bedded sandstones and coarse breccias that accumulated upon the flat desert plain. Occasional wind-polished rocks, known as ventifacts, can be found amongst the deposits, which are comparable to those accumulating in the Sahara today. A lack of fossils perhaps highlights the harsh conditions that existed during the sediment’s emplacement.

Upper Permian

Further orogenic activity to the south caused the land surface to buckle and fold forming a broad inland basin. To the north and east, a communication developed with the Zechstein Sea, which rapidly transgressed across North East England to occupy the former desert plain. Further subsidence meant that this new arm of the sea reached depths approaching 200 metres further east, though locally the area was close to a shoreline. This marginal environment was colonised by coral reefs, stromatolites, and a rich fauna of other marine creatures. Their remains combined with a restricted input of fine sediment blown from the nearby desert to produce beds of limestone. This reef environment was to be short-lived however, as a new period of uplift caused the English Zechstein to become cut off from the main water body. Conditions rapidly deteriorated in the isolated sea as evaporation of its diminishing waters concentrated their mineral content. During the final phases a sabkha zone developed, made up of hypersaline lagoons, pools of hot mud, and glittering beds of evaporites stretching across the desert.

The Upper Permian is typified by five such incursions, followed by evaporation, of the English Zechstein (EZ1-5) with the later episodes never attaining great depth. The resulting strata comprise various limestones and mudstones with intervening beds of evaporites. The latter became important commercially during the late 1800s when salt extraction on Teesside constituted the beginnings of today’s modern chemical industry. Later, anhydrite was mined in great quantities around Billingham, and potash along with rock salt is still extracted from deep mines, over a kilometre below the surface, at Boulby, near Staithes.

Fossil content within the Permian succession diminishes the higher up one looks, and this is not simply an effect of the harsh conditions locally, but is reflected within the fossil record worldwide. During what has become known as the Permian Mass Extinction, some 96% of all marine species died out never to return, with a lesser, though not insubstantial, number of terrestrial creatures joining them. The event is billed by geologists as the greatest extinction so far suffered by life on Earth. Life’s tenacity, however, never fails to amaze, and the survivors of this catastrophe would, over the next 40 million years or so, adapt and radiate into niches vacated by many of their predecessors to produce a whole new era of life on Earth.

For further details contact Beth Andrews, River Tees Natural Heritage Officer, at
Tees Valley Wildlife Trust
Margrove Heritage Centre
Margrove Park
Boosbeck
TS12 3BZ

Email beth@tvrigs.org.uk or phone 01287 636382

Fossils are the remains, impressions or traces of animals and plants from long ago which have been preserved within rocks.

They help us to understand how life has evolved over time. Fossils come in many forms, they may be shells of bivalves, dinosaur footprints or the delicate impressions of leaves. The state of preservation of fossils varies greatly depending on the structure and composition of the original organism, the type of rock they are preserved in as well as what has happened to that rock since deposition.

There are three main types of fossils;

• a body fossil, such as an ammonite shell,
• a trace fossil, patterns left by animals such as dinosaur footprints, and
• chemical fossils which can be detected geochemically in the rocks.

In the Tees Valley we find many examples of the first two types.

Most animals and plants are eaten either on, or after death and their chemical constituents recycled. A few, however, find their way into quiet areas where sediment is accumulating. Even fewer survive the violent upheavals of our planet. Only a tiny fraction of the fossils which do form are ever found and studied.

Industrial Heritage

The foundations of Teesside’s industry, heritage and development were built upon the geology of the area. The main economic interests were focussed upon the ironstone in Eston Hills and throughout East Cleveland, enabling the iron and steel explosion around the river Tees.

Other commodities have been mined including limestone, sandstone, potash and clay, each spawning various associated industries.

The Geotrails are a series of guided walks around interesting geological places within the Tees Valley. They are designed to be downloaded and printed out to take with you. The trails aim to give you a bit more information on the landscape around you and include geology, history and industrial archaeology.

If you don’t fancy a paper guide then why not try downloading our podcasts that can be taken with you and guide you as you make your way around.

If you are interested then click on the link buttons on the left hand side.

The word ‘Geology’ comes from the Latin ‘Geo’ meaning Earth and ‘Logy’ meaning study of. So it literally means study of the earth.

It is the rocks of the Tees Valley that have brought industry and money into the area. Some of the rocks to be found here are more important than others. But all of them have in some way played a part in building the Tees Valley.

To find out more about any of the rocks in the Tees Valley select a geological period from the list below. The geological periods are given in chronological order (order of time) with the oldest period at the bottom of the list.

• Quaternary
• Tertiary
• Jurassic
• Triassic
• Permian

Click here for a detailed geological timescale.

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