William Smith's Geological Map of England and Wales Map Man

A good map will show us where we are and help us on our journeys.

A better map will transform the way we see the landscape around us.

But in 1815, a map was published which did much more than that.

It gave us a new means of understanding Mother Earth.

The geological map of England and Wales peeled back the soil

and, for the very first time, showed what lay beneath.

The map was all the work of one man - William Smith.

And the end result of that work was cataclysmic.

The truth about the formation of the Earth began at last to emerge.

I'm going to take a journey from the Bristol Channel, across the West Country, to the English Channel.

My quest is to discover exactly how Smith's map

transformed the way the British people thought about their own island.

In 1815, as the Napoleonic Wars drew to a close,

William Smith published his geological map of England and Wales.

For the first time anywhere in the world, Smith's map revealed the geology of a whole country.

But it wasn't the work of an academic geologist.

William Smith was a working man - a West Country surveyor -

and he struggled for more than 25 years to have his ideas accepted.

Smith's map was the product of practical observations as he went about his business,

but making it entailed an enormous paradox - to understand the map on the horizontal axis,

you have to understand what's going on deep under the ground.

So a geologist like Smith doesn't see what the rest of us see.

He feels the world through the soles of his feet.

To a man like Smith, walking along, his eyes cast down,

none of this beautiful surface geography would exist.

It's all been peeled away. It's just a decorative veneer.

He'd be looking for these - stones -

because every stone tells a story.

These were the voices Smith heard

from his subterranean world.

My journey begins in a place Smith knew well - the Forest of Dean in Gloucestershire.

On his map, its carboniferous rocks are marked in black. In his day, the forest was booming.

There was a fortune in the trees, as they were harvested for Nelson's navy.

But it was booming for another reason. As the 18th century ended,

England was undergoing an economic transformation - the Industrial Revolution -

and that depended on minerals and the rocks beneath the earth.

-I'll see you down by the entrance.

-Yeah. I won't be a moment.

The early 1800s were a time of intense intellectual and economic ferment.

The part played by Smith was to apply science to the furtive business of mineral prospecting.

In the world of prospecting, there was one cash-rich rock above all.

It was black, it was dirty, it burned brightly, and it came from holes like this.

-God, it's wet and cramped down here.

-Not to worry.

-How do you get used to this?

Not the sort of place to be if you don't like filth, mud, running water and pitch dark, is it?

'This coal mine in the Forest of Dean was started in the 1820s on the advice of Smith himself.

'But how did he know where the coal was? Nick Evans still works this mine with five colleagues,

'and although the technology's a bit different, conditions here haven't changed much since then.'

The style of working and the supports will be as it was in Smith's time.

All this on the side is what we call marl.

And the marl's a dangerous stuff, which is why you've got to have these supports holding it all up.

-It's a fairly unstable material, yes. We'd better make our way back up.

-OK.

'Even then, when labour was cheap, searching for coal was enormously expensive,

'and if you didn't find coal, you could lose a fortune.

'So everyone wanted to find a way of knowing where the coal was, and that's where Smith came in.'

This is the coalface.

'The coal is concealed in several layers of different rocks.'

-Oh, yeah.

-Here, right at the very top, we've got the sandstone.

-That's this layer here?

-That's this here.

Then, underneath that, you've got the marl.

-So that's the junction between the sandstone and the marl there?

-Mm-hm.

And then here, the coal.

-Underneath the coal, there's this clay.

-That's this gungy, sticky stuff?

-Yes.

So there are four layers all within about a metre here.

'In 1791, when he was just 22, Smith was asked to survey some coal mines just like this,

'in Somerset. There, the young man made his first revolutionary discovery.

'He noticed that the layers of rock above and below the seams of coal

'always occurred in exactly the same order wherever you were.'

-The black layer, the coal, that's always going to be lying underneath the marl. Is that right?

-Yes.

So wherever you've got marl, go down a layer, you'll find coal?

-Correct.

-Which is what William Smith must have known.

He didn't have to go underground to know where the coal was. He'd look for outcrops of marl.

'But it was confusing. Many rocks looked similar to each other.

'How could you be sure that a rock really was what you thought it was?'

Occasionally, we come across these.

That is the root of one of the giant tree ferns that formed the coal.

'This root has been preserved and turned to stone by time and the pressure of the rock.

'It's a fossil.'

-The long-lost forest comes to light again.

-Oh, yes.

'It's very difficult for us today to realise how ignorant people were in Smith's day about fossils.

'With their bizarre, often symmetrical patterns and strange shapes,

'these were regarded as wonderful, curious stones.

'They were given exotic names, like thunderbolt, devil's toenails, snake stones,

'and they were all put there, of course, on the third day of Creation by God himself.

'So they weren't extinct animals at all. They were religious relics.'

But these extraordinary stones held the key to mapping underground Britain.

As he tramped the country for his employers,

Smith noticed that you found one kind of fossil in one rock layer and another in a different layer.

But why? How did that connection work?

To find out, I'm going to follow Smith back towards his native Oxfordshire, into the Cotswolds.

On this side of the Severn, the Cotswold hills

come crashing down in a steep escarpment to the plain below.

It's the perfect place to investigate one of Smith's most important discoveries.

Smith was the first man to recognise the value of fossils

as a means of identifying particular layers of rock.

It may seem hard to believe today, but once, millions of years ago,

the entire height of this escarpment was under the sea.

In fact, the whole of it is made of rocks

created by the steady accumulation of material on the sea floor.

Rocks like this are known as sedimentary rocks,

and they were laid down at different times as evolution progressed and species evolved.

So if there are fossils in them,

the species of fossil present will identify the rock exactly.

No matter how far apart two outcrops of the same rock were,

the fossil groups in them should be similar.

Now I'm going to put Smith's big idea to the test.

This is the rock that was laid down 170 million years ago,

when this part of England was covered by a shallow, warm ocean.

And on the bed of that ocean, all sorts of things like coral and scallops were growing.

So where shall I start?

All I'm looking for are oysters, in particular, cos there should be lots of those around here.

There we are. Here's a broken oyster shell, and here's another one. If I can get those out intact...

..which I can't. Oh, there it is. That's pretty good.

There's another. I'll get that one out.

There we go.

Both those have got a bit shattered, but let's try this one here.

We'll get a better example.

Eureka!

Fantastic!

Incredible.

Look at this.

This is a really good oyster. 170 million years old.

That's three times as old as the dinosaurs. Now, according to Smith,

I should find this family of fossils all the way through this yellow band across his map.

Before Smith's time, most people identified rocks by referring to what they were made of -

sand or mud or lime - but Smith's method offered a far better way.

It meant that you could distinguish between two kinds of rock, even if they looked the same.

Now I'm going to walk right down the yellow oolitic band on William Smith's map,

to the other end of the Cotswolds, to see if it's really true.

Down here, outside Bath, the rocks seem to be the same kind of oolitic limestone we saw outside Cheltenham.

The question is, will I find the same kind of fossil?

And to make sure that everything's fair and above board, I've asked Hugh Torrens to join me -

now a professor of geology, but a man, like Smith, who has collected fossils since he was a boy.

Blow me! Look at this.

It's a beauty.

-Is that an ammonite?

-Yes. That's the inner whorls... and these are the sutures.

-Is it possible Smith walked up here, found it and chucked it aside?

-He might have dropped it to confuse us!

Smith bought a house in Somerset because this was where the work was. The area was full of coal mines.

What Hugh and I are going to do is to put Smith's idea to the test -

the idea that fossils can identify the rocks.

-This hole was actually excavated by Smith himself.

-Smith dug this?!

-Yes. This is rather a sacred spot.

Is it possible that he chipped some fossils out of this oolite?

Well, in his collection in London, he records fossils from this rock - the Inferior Oolite -

-from his house there.

-Here, let me get my fossil out. Here it is. Here's my oyster.

-Right.

-Is this oyster from the same group of fossils?

-The same stratum? Yes.

-This is Inferior Oolite, Smith's Bath stone.

-And here's...

That's an oyster.

-This oyster lived with my oyster?

-Yes, yes, yes.

-Same group of fossils?

-They are of the same period in time, in the same rock unit.

-14 miles apart.

-Yes.

-Thousands!

-It's packed with fossils, until you get to the sand,

then the fossils become different and rather rare. His work as a mineral prospector has been ignored.

Until you know the order of rocks, you can't work out where you are.

Smith was the first person to order the rocks of the whole country,

from the capital to the source of its main fuel, coal.

So he went from London clay right down to the carboniferous, down to where the main money was made,

and he was able to tell them, "You can find that here."

But he was more able to say, "You'll NEVER find that there. Stop trying, you're wasting lots of money!"

-There's a crinoid stem.

-Oh, yes. What's a crinoid stem?

It's a sea lily. Like a student, it sits rooted to the ground with its mouth open, expecting to be fed!

What made Smith more extraordinary was that he was doing this at a time

when people were only just realising how old these rocks were.

I don't think Smith had any real realisation about the can of chronological worms he was opening,

but he certainly opened the can.

Other geologists asked, "If this sequence is so thick,

"can we use the thickness to work out how long it might have taken?" The first estimate, in Smith's lifetime,

was that it must be a million years because we know how slowly mud in the Bristol Channel is being deposited.

We have several thousand feet of thickness. Do your sums. You come to at least one million years.

At the time Smith was working here, the Church of England laid down

that the world was created at nine o'clock in the morning

on the 23rd of October 4004BC.

That, said the bishops, was what the Bible tells us.

So Smith's new geology was rather unsettling.

Even Smith was a bit perplexed. He wrote in his diary about time testing the faith of many,

but his quest was still firmly practical.

For him, the map was the thing... not the whys and the wherefores.

The first thing that strikes you when you look at this map today is how exquisitely beautiful it is.

But it may not have looked quite like that to the first people who saw it in Smith's day,

because this is a map which has exposed the innards of Britain.

Many people would have looked at this as if they were looking inside their own body for the first time.

What we're seeing here are the working parts of an island.

Anybody wanting to make the most out of Britain's own natural resources need only look at this map.

The colours tell the whole story.

The yellow band of oolite down here... Fantastic building material.

New towns and cities springing up during the Industrial Revolution.

The blue marl here for brick-making.

These coloured... The chalk areas green,

ideal for putting on lime-deficient fields to improve crop yields.

And, of course, the chalk of Britain is largely pasture, which is green.

And the black over here in South Wales, the coal - the fuel of the Industrial Revolution.

The fascinating thing is that these colours were, on the whole,

adopted as the international standard for geology maps,

so Smith set the template for the colour in geological maps with this great masterpiece.

Above all, this is a map for the new industrial Britain, the pumping heart of a world empire.

By now, Smith had effectively established the basis of modern geological technique.

He knew that rocks were arranged in layers under the ground.

He knew that you could identify those layers using the fossils.

But how was he going to prove that there was more to it than that?

That the sequence of layers was consistent everywhere?

At this point, he found himself to be the right man in the right place.

He'd come to Somerset to survey coal mines,

but in the booming industrial expansion, there was another way a surveyor could make his mark -

canals.

For Smith, who was both a surveyor and a geologist, this was a fantastic, historic opportunity.

This overgrown industrial relic is where Smith's ideas about the layering of rock were confirmed.

In 1794, 25-year-old Smith - young, ambitious, driven -

got a job surveying the route of the new Somerset Coal Canal.

There were two branches of the canal right here, about ten miles apart,

and it gave him a fantastic opportunity to conduct his own geological experiment.

As the navvies cut down through the surface of the earth,

and before these facing stones had been put on locks like this,

Smith was able to look at the layers of rock, and pick the fossils out.

What he found was that the layers and fossils in this cutting

matched up with the layers and fossils in the cutting ten miles over there.

From this moment on, Smith knew for sure that wherever you stood in England and Wales and Scotland,

the layers of rock would be the same, and THAT was the basis of his great geological map.

Smith's experiment had confirmed all his theories.

If you wanted to cut a canal or sink a coal mine,

it was no use loosely identifying the layer of rock on the surface and then digging down.

You had to understand exactly what layer you were on, and where it came in the sequence.

His success made it possible for him to warn prospectors with confidence

about where to sink their mines and build their canals,

but by the end of the 1790s, Smith's ambitions were beginning to embrace the whole of England,

and elsewhere, he might not have the convenient opportunities he'd had in Somerset.

There was another way, though.

To make his map, what Smith needed to do was to relate the sequence he had found in the Somerset coalfield

to those he found on hillsides in the rest of England.

He did it by constantly travelling, as I am, close to the ground.

Smith knew that, even if the rock layers themselves were consistent,

the particular rock you found at the surface varied from place to place.

In other words, you wouldn't always find the same rock at the top.

So wherever he went, Smith took detailed notes about what he found on his travels.

Here, at Glastonbury, is one of those places.

According to Smith's notes, there was a simple sequence of layers going up the hill outside the town.

But if only geology was always that easy!

The rock layers on this hill are horizontal, but in other parts of the country, it's more complicated.

Smith's encyclopaedic recording of the rocks never stopped

and it led him to a remarkable discovery.

The sequence of layers he'd found in the rocks below the earth

seemed to be repeated on the ground as he travelled across the country.

After Lias, the limestone, then the green sand, the chalk and the clay, as you went eastwards.

At first, this was puzzling.

Why should the vertical sequence of layers be repeated in the horizontal as well?

But then he was struck by a brilliant analogy to explain it.

Now, if geology was really simple, England would look like the monster sandwich that I'm going to eat,

with the youngest rocks on the top - the chalk - and the older rocks down below, but Smith had a revelation.

He realised that England's rocks had tilted, rather like that,

and that something had exposed the older rocks down below,

so that as you travelled from east to west across England,

you crossed successive outcrops of rocks. And that's exactly what you see on Smith's map,

with the younger rocks in the east, progressing across

to the older rocks in the west. Smith had made a profound discovery.

What he'd recognised was that the sequence of rocks he'd identified going down into the earth

was, because of the tilt, replicated across the face of England, as well.

So he was able to include a little cross-section diagram on his map, which showed how the sequence lay.

But where could you actually see the evidence for that idea? And how could Smith prove it?

The obvious place is, of course, on the south coast of England,

where the ceaseless crashing of the Channel tides has carved away the rocks for all to see.

And it's less than 50 miles away.

On the Dorset coast, you can see some of the most beautiful seascapes

in the world, but it's more than just a pretty sight.

It's become crucial to the geologists' view of the world.

But had Smith sorted out the geology of England?

Not a bit of it! His layers were about to receive the shock of their lives.

Well, here I am on top of Golden Cap, one of the most popular playgrounds in southern Britain.

It lies roughly midway along the most spectacular geological coastline...probably in the world.

In the hundred or so miles between the River Ex down there and the Isle of Purbeck along there,

you can walk across 185 million years of the Earth's history,

from the sandstones and mudstones in the west, towards the younger limestones and chalk in the east.

So if I take a walk now eastwards, I should cross successive layers of rock that get younger and younger,

but I've a sneaky feeling, and so did Smith, that geology is not quite as simple as a sandwich.

This part of the English coast has been designated a World Heritage Site.

It provides almost a complete sequence of the sedimentary rocks

laid down between 250 and 66 million years ago.

So as you walk eastwards, you cover at least a million years for every mile you walk.

And because some parts of the sandwich are softer than others,

the sea has got in in some places and played merry hell with the rocks.

But you also begin to realise that the layers haven't just been tilted and left to erode.

Something much more dramatic has happened.

And if we look at Smith's map,

we can see that, true to form, William Smith realised that something odd was going on.

It's clear that this coast was not just made of simple layers of rock.

Here in the Isle of Purbeck, Smith's east-west progression has become a north-south one.

Well, this is the famous Lulworth Crumple.

It's a brilliant example of what can happen when savage forces fold the surface of the Earth.

All those layers of hard rock have been folded over on themselves,

like so many slices of bendy cheese and ham.

It almost looks as if my clean-cut geological sandwich has had a very bad day in the rucksack.

How did those rocks get like that?!

Smith and his contemporaries were still only coming to terms with the real age of their rocks.

The cataclysmic events which led to the folding of the Lulworth Crumple

was something they couldn't ever have imagined.

But Denys Brunsden can.

He's spent his whole life working on this coast, analysing every cliff and landslide.

It was largely because of his efforts that this coast was declared a World Heritage Site.

If anyone can tell us what happened to Smith's neat layers of rock, he can. It's an astonishing story

'of crashing continents, volcanic mayhem and upended rocks.'

We've actually got a bay

cutting across the grain of rock.

When you look at the William Smith map, they're running this way.

We're just looking at the end now.

We can see that, instead of the rock gently dipping, they're right up on end, like that.

-Sticking up vertically.

-Here, they're almost overturned and we've just got the gem of the Dorset coast.

-One of the gems of the British coast!

-Or of any coast! Durdle Dor.

-It's glorious. That's why it's World Heritage.

-We get younger that way,

but it's because the rocks, instead of being like that, are like this.

Millions of years ago, the solid rock of Dorset was twisted and bent by huge geological events.

-The whole of the Earth's crust was on the move.

-It's the force of Africa moving north,

hitting Europe, of course, and much further south, forming the Alps.

But those stresses were still being felt up here. It's very confusing. Very difficult to work out.

-So, we've got a gigantic collision between two of the Earth's plates...

-A long way to the south.

-..but the ripples reached the whole way to Britain.

-Yes. The outer ripples of the Alpine storm.

LOUD CRASHING

To William Smith, who had no conception of this kind of turmoil,

a place like this must have been an absolute nightmare, but, even so,

his techniques are still completely valid. Smith's map was crucial in working out what happened,

as it gave people a concrete picture of the layers beneath the soil.

It was Smith who provided the hard data for others to analyse.

He's actually producing evidence of great forces in the Earth

that have tilted something that was horizontal and stood it on end,

and I think, for those practical geologists, he was providing a whole systematic way

of these complicated things that you have to observe, and suddenly they were into theories of Earth.

It's setting up great principles. They were doing something new.

It was a wonderful, wonderful time. Tough, but a nice place to be.

It was on this very coast that the discoveries were made

which established the modern science of geology.

Here, the first dinosaurs were identified, as well as an entire fossil forest.

Even today, this coast is vital for geological research,

but over it all hovers the spirit of William Smith, the first man to conceive of its true nature.

Smith's genius was to recognise that the age-old practice of map-making

could be applied to the subterranean world, a world which was invisible to all but himself.

But this humble, systematic foot-slogger created more than a map.

Smith's monumental work laid the foundation for future scientists

to understand the structure of the Earth itself.

Subtitles by Susan Mason BBC Broadcast 2004

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