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Animals and plants flourished on earth for
millions of years before humans appeared.
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The direct evidence comes
from one source only;
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from their remains
that can be found in rocks, from fossils.
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Some are spectacular and dramatic,
complete skeletons of huge reptiles.
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Others are the merest trace of imprints,
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left by such insubstantial creatures as jellyfish.
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Many are the remains of creatures
quite unlike any that exist today.
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Fossils can be found all around us
if we know where to look.
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The south of England, the Dorset coast,
and a world-famous fossil site.
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Heavy rains have drenched
the clay and limestone cliffs.
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The rocks are slipping.
New surfaces are being exposed.
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Fresh fossils
could have been revealed overnight.
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Peter Langham regularly patrols this coast
searching for them
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and he knows that the day after a storm
is the best time for finding something interesting.
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A couple of likely-looking bits of stone.
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Why? They look like all the rest to me.
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Really, it's from the right horizon.
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It takes a lot of experience to judge
which of the many boulders in a cliff like this
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is likely to have a fossil inside it.
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But, then, Peter has been doing this for years.
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Generally, these split fairly easily.
They've got good bedding plains.
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Let's see what happens.
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(LANGHAM) We're in luck.
(ATTENBOROUGH) Gosh!
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That's one of the most well-known
ammonites from Lyme, Asteroceras.
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That's beautiful.
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Fossils don't always appear every time
you hit a nodule of rock with a hammer,
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but they do so surprisingly frequently
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if you can recognise the right sort of nodule
and know where to find it.
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I used to come to these old ironstone quarries
in Leicestershire as a boy to look for them,
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and the moments of success,
when the rock fell apart
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and revealed a shell
that hadn't seen the sun for 200 million years
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and that I was the first human being to see,
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seemed to me then, as, to be truthful,
it still seems to me now, to be moments of magic.
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It's a beguiling business, for you know that,
even if you've not found anything much so far,
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the very next blow of your hammer
may suddenly reveal something amazing.
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That's not bad, but if I keep looking
I should be able to do rather better.
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Slowly you begin to get your eye in,
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and soon you will start to recognise
the particular glint, the tell-tale curve,
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the slight change in colour that indicates
the tip of a fossil sticking out from the rock.
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It doesn't take long
to gather quite a varied collection.
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They all seem to be the remains
of animals that lived in the sea.
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But the local people, some at any rate,
refused to believe that.
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"How could they be?" they would say,
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"When we are in the middle of England,
far from the sea,
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"and when these fossils are buried in the rock,
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"far below the surface of the earth.
How could that be?"
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Instead, they had their own explanations.
They said, for example,
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that these were the toenails of the devil.
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And this, these impressive, bullet-shaped objects,
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and there's some in the boulder
on which I'm sitting,
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those, they said, were thunderbolts,
made when lightning struck the earth.
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And the most beautiful of them all,
these ammonites,
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those, they said, were snake-stones,
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and they came in two kinds,
big ones, like that, and little ones.
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Farther north, up in Yorkshire, near Whitby,
where exactly the same fossils are found,
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the people had a detailed explanation
as how that had come about.
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They said that back in the seventh century,
an early Christian saint, Saint Hilda,
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had wanted to found an abbey
but discovered the place was infested by snakes,
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so miraculously she turned them all to stone.
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0f course, there's one problem
with that explanation:
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None of these so-called
snake-stones have heads.
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But when the devout pilgrims came
to the site of this miracle,
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They carved on heads onto the snake-stones,
so that they looked rather more convincing.
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But there are some fossils
that are so perfectly preserved
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that their animal origin simply cannot be denied.
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These tiny creatures are imprisoned in amber,
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a hard, stony substance that's found in lumps
in mudstones and sandstones.
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Who can doubt that these,
so complete in every bristle and antenna,
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are truly ants, scorpions and flies?
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But how did they get there?
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Amber was once liquid and sticky,
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resin trickling down the trunks of trees
that grew in swamps some 30 million years ago.
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Insects were attracted, then as now,
by its sweet smell,
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and flew or crawled towards it, with fatal results.
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The resin gradually hardened into solid lumps.
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Eventually, the tree itself died...
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... and the long, slow processes
that lead to fossilisation began.
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Mud and sand washed in by the sea
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slowly settled on the resin lumps
and buried them.
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As millions of years passed,
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the layers of sediment were compressed
and compacted under their own weight,
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and turned into mudstones and sandstones
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and then were pushed and buckled
by colliding continents to form mountains,
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like these in the Dominican Republic
on the Caribbean island of Hispaniola.
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And since amber is highly valued
for making jewellery,
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men today burrow deep
into the hillsides to look for it.
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The shafts are steep and may go
as much as a hundred yards into the mountain.
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The amber miners
have to chisel away tons of stone
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before they find the particular layer
where the lumps of resin have accumulated.
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But once they find that seam,
they often discover piece after piece.
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(SPEAKS SPANISH)
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It's difficult to tell what's inside pieces like this
when they've just been dug out,
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because the surface is all broken
and pitted and dirty.
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But when they are polished,
they may reveal the most extraordinary things.
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Many pieces are quite clear,
with nothing whatever in them.
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Those are the ones that are valued for jewellery.
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But one in every dozen or so
has the remains of some kind of creature.
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Backboned animals were mostly strong enough
to pull themselves free from the resin,
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but occasionally they failed,
and these are the rarest of all amber fossils.
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A tiny lizard.
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And a frog.
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Insects are the commonest
and were sometimes caught in action.
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An ant carrying a pupa.
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A bug beside a leaf
from which it might have been sucking sap.
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A beetle apparently walking up a twig.
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Flying insects with even
their delicate wings undamaged.
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And a whole swarm of ants,
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so perfectly preserved that you can even see
the facets in their 30 million-year-old eyes.
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Mud itself doesn't embalm bodies as resin does,
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but even mud can preserve an extraordinary
amount if it accumulates in a particular way.
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It must settle fast before decay dissolves the
flesh and sinews that hold a skeleton together
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and before the bones are separated, washed
away and, perhaps, broken into fragments.
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As more mud settles
in thicker and thicker layers on the bottom,
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so the body beneath is squashed flat.
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The mud may be so glutinous
that it shuts off oxygen,
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and then some relic of the flesh may survive.
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But even if that entirely disappears,
the scales and bones may remain,
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and when the mudstone is cleared away,
the fossilised body is revealed in great detail,
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sometimes down
to the delicate tracery of its fins.
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So wherever you find sandstones or shales,
mudstones or limestones
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that were once sediments
at the bottom of a sea or a swamp,
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you stand a chance of finding fossils.
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And it's not only animals that may be preserved
in this way, sometimes even plants are.
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Some 220 million years ago,
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these logs were part of trees
that grew in a great coniferous forest
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in this part of Arizona in the United States.
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When the trees died,
some of them fell into the rivers
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and the logs were carried downstream
and ultimately buried in these sands and gravels.
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And now, although they look exactly like wood,
they are, in fact, solid stone.
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Because they are no longer
flexible wood but brittle rock,
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these trunks have broken into segments
as if they had been sawn into short lengths.
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The bark has been perfectly preserved
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so that you can see its grain and the knot-holes
from which small branches once sprang.
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The wood itself has been replaced
by a mineral, quartz,
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but the annual growth rings can still be seen,
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so that you can calculate just how old
each huge tree was before it fell.
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In fact, these fossils retain so many
of the characters of the original trees
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that botanists can work out
exactly what kind they were.
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They were cypresses, related to the swamp
cypresses that still grow 1500 miles to the east
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in the flat, waterlogged plains
along the coasts of Florida and Louisiana.
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These forests give us a very accurate picture
of what the trees of the petrified forest were like
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when they were alive so long ago.
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But conifers were not by any means
the first trees to clothe the earth.
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150 million years earlier still,
there were trees of a very different kind.
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These, like giant horsetails,
also grew in coastal swamps.
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Sometimes there were changes
in the level of the sea,
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and then water swept into the swamps,
bringing with it great quantities of sand and mud,
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which settled around the bases of the trees,
burying them and killing them.
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The outside of these particular trees
had extremely tough bark,
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but the wood inside was soft and pithy,
and when the tree died, it decayed very rapidly.
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And as it decayed,
so more sand settled in in place of the wood.
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But the bark remained for much longer time,
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separating the sand inside the trunk
from the sand outside.
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Over millions of years,
the sand compacted and formed sandstone,
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and when men came to quarry it,
it broke away where the bark had once been,
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so revealing these extraordinary trunks.
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So although the wood itself
has totally disappeared
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and these, in effect, are just casts of tree trunks,
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they nonetheless give a vivid impression
of the forest that grew 350 million years ago
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where today the city of Glasgow stands.
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But this familiar substance
is the actual remains of the plants themselves.
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First the rotting plants formed peat,
and that in turn was compressed into coal.
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Tom Phillips has devoted his life
to working out exactly what those plants were.
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He's travelled the world collecting specimens,
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but most of his research has been done
with material he found here,
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in the great opencast coal mines
of Illinois in North America.
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The sand that buried the peat
crushed it so severely
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that almost all the details
of the plants were destroyed.
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But within the seam are hard lumps called
coal balls, and they are much more interesting.
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It's calcium carbonate that has precipitated
and filled up all the voids in the plant tissue,
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so that as compaction took place and we went
from thirty feet down to five feet of coal,
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the dimensions of this weren't altered.
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So it was a kind of lump
in the middle of this peat bog
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where there was a lot of calcium carbonate
which turned into limestone, forming a ball,
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and this didn't squash.
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To see just what a coal ball contains,
you must first cut it into two.
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Then you dip it in a tank
of weak hydrochloric acid,
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which etches away the calcium carbonate
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and leaves the plant remains
standing just proud of the surface.
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Acetone is poured over it...
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... a transparent sheet of acetate is laid on that
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and then left to dry
to form what is called a peel.
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The peels are fairly easily removed.
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Like so. You can tell the colours even before
we look at them with a microscope.
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This is the wood. It has a different colour
from the surrounding tissues.
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(ATTENBOROUGH) 0h, perfect!
(PHILLIPS) Notice what large cells.
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(PHILLIPS) Most of the tissues are still intact
and preserved to some degree.
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(ATTENBOROUGH) So that's a stem there?
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(PHILLIPS) It's a rather fancy stem.
It has several cylinders of wood inside,
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rather than one like most plants.
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All of this tissue that extends round the outside,
you can see the basket of bundles,
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and the dark cells are support cells.
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This was a tree, not a very tall tree,
maybe 15 feet or so,
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and less than a foot in diameter.
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As a result of work like this,
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we can now picture very precisely
the ancient forests which formed coal.
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We know the anatomy of the stems in such
detail that we can reconstruct individual plants.
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Many were like the living horsetail plant,
except that these grew to 50 feet high.
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This is a section of a cone which produced the
male spores and grew on another kind of tree
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around the base of its leafy crown.
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The female seed-like structures had tiny sails
and floated away to other parts of the swamp.
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We can deduce all this
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only because coal balls have preserved
the structure of the plants in microscopic detail.
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For a long time it was thought that
that kind of perfection of preservation
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was to be found only in plant fossils.
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But look at this:
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This is part of the jaw of that great flesh-eating
dinosaur Tyrannosaurus rex.
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It used to be said of superb,
fossilised bones like this
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that in some miraculous way, minerals had
replaced the bone molecule by molecule.
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But scientists here
in the New Mexico Museum of Natural History
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have had this bone analysed chemically.
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The spaces within the bone
have indeed been filled with silica
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but the substance of the bone itself
is chemically almost identical with modern bone.
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Not only that, they have also
taken sections from the bone,
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00:21:10,727 --> 00:21:15,323
and when you look at these
under the microscope, this is what you see.
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These are grains of the mineral filling,
quartz, or silica,
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but here are bone cells.
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00:21:27,807 --> 00:21:30,958
And these, with their cell walls
and central spaces,
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are almost identical in appearance
with the bone cells of living reptiles.
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This is the actual substance of a dinosaur.
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So fossils can reveal
in the most extraordinary detail
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00:21:47,527 --> 00:21:50,803
the anatomy of long-vanished
animals and plants.
223
00:21:50,887 --> 00:21:56,007
But how do you find them? How would you know
this bleak spot was a good place to look?
224
00:21:56,167 --> 00:21:58,158
Well, you need a practised eye,
225
00:21:58,567 --> 00:22:03,641
and few are more experienced than those
of Stan Wood, a collector from Edinburgh.
226
00:22:03,967 --> 00:22:09,166
He took me to this shore in northern Scotland
to look for fossil fish.
227
00:22:10,207 --> 00:22:15,520
(WOOD) Grab that. That's it. Ah, at last.
228
00:22:15,967 --> 00:22:18,162
(ATTENBOROUGH) Gosh.
229
00:22:18,367 --> 00:22:21,916
(WOOD) There she is up there.
(ATTENBOROUGH) That's the head, huh?
230
00:22:21,727 --> 00:22:25,037
That's the head. Down here's the tail.
231
00:22:25,567 --> 00:22:29,276
In between, the scales of the body.
232
00:22:29,407 --> 00:22:31,523
They're better preserved down here.
233
00:22:31,327 --> 00:22:35,878
In fact, the body itself is preserved.
234
00:22:36,127 --> 00:22:39,199
If I can just lift that up...
235
00:22:39,487 --> 00:22:43,275
I can actually lift that out
236
00:22:43,327 --> 00:22:46,160
as an ancient kipper.
237
00:22:47,647 --> 00:22:50,241
The scales are on both sides, you see?
238
00:22:50,047 --> 00:22:52,322
It's now carbonised,
239
00:22:52,447 --> 00:22:57,965
but at one time that would have been
a nice juicy little salmon of the period.
240
00:22:59,447 --> 00:23:03,759
So fossils up here
are relatively common and easy to find.
241
00:23:04,007 --> 00:23:08,364
But sometimes, and often in the places
where you'd most like to find them,
242
00:23:08,327 --> 00:23:12,115
they seem so scarce as almost not to exist at all.
243
00:23:12,247 --> 00:23:17,082
This is just one of those places.
It's a quarry in Scotland, just outside Edinburgh.
244
00:23:17,527 --> 00:23:22,806
The rocks in it were laid down
around 338 million years ago,
245
00:23:22,807 --> 00:23:25,685
at a crucial period in the history of life on earth,
246
00:23:25,687 --> 00:23:31,444
when animals with backbones were,
for the very first time, crawling out onto the land.
247
00:23:32,887 --> 00:23:35,606
A few extremely important
fossils of these creatures
248
00:23:35,767 --> 00:23:38,804
were discovered in this quarry
in the 19th century.
249
00:23:39,127 --> 00:23:42,881
But then, search as people might,
they could find no more.
250
00:23:42,967 --> 00:23:46,846
Until, that is, Stan Wood started looking.
251
00:23:46,927 --> 00:23:49,646
Now, Stan, why do you think
there's anything in that?
252
00:23:50,087 --> 00:23:52,726
Because I've split it vertically,
253
00:23:52,487 --> 00:23:57,322
that's at right angles
to the layers of rock that was laid down,
254
00:23:57,767 --> 00:24:00,235
and when you cut it vertically,
255
00:24:00,167 --> 00:24:07,164
in this case, we're seeing marks along the plane...
256
00:24:07,367 --> 00:24:09,517
- There?
...which indicate bone, yes.
257
00:24:09,767 --> 00:24:15,160
That's bone because I've been working
on this kind of rock for a while
258
00:24:15,527 --> 00:24:17,597
and I recognise it as bone.
259
00:24:17,447 --> 00:24:23,044
What I'm hoping, against hope, perhaps,
is that there's a little skull in here
260
00:24:23,207 --> 00:24:29,043
of one of these very rare
early four-legged animals.
261
00:24:29,287 --> 00:24:34,725
The idea is to now try and split it
along the plane that the skull is lying,
262
00:24:35,047 --> 00:24:39,916
taking care to avoid damaging the skull
wherever possible.
263
00:24:39,847 --> 00:24:43,283
So I'm placing the chisel to one side.
264
00:24:47,487 --> 00:24:51,526
They're not easy to recognise
because they're so small.
265
00:24:51,327 --> 00:24:53,682
There's not that much to see.
266
00:24:54,687 --> 00:24:58,726
Now, what on earth is this?
267
00:25:01,887 --> 00:25:05,084
I'll try and put this together and see...
268
00:25:05,527 --> 00:25:07,404
It is a skull.
269
00:25:07,927 --> 00:25:12,557
I think we have parts of the body
running down here at right angles to the skull.
270
00:25:12,727 --> 00:25:14,718
- Do you see that, David?
- I do.
271
00:25:15,047 --> 00:25:17,845
Is that the backbone, there?
272
00:25:17,927 --> 00:25:21,203
(WOOD) The skull, as it were, has turned left.
273
00:25:21,687 --> 00:25:25,316
(WOOD) Look.
There's one of the eyeballs, you see?
274
00:25:25,087 --> 00:25:28,079
(WOOD) It's shot out...
As the skull's been squashed,
275
00:25:28,447 --> 00:25:33,396
the bone surrounding the eye socket
has shunted out to the side.
276
00:25:33,407 --> 00:25:38,959
That round hole is actually one of its eyes.
The other eye would be over here.
277
00:25:39,167 --> 00:25:43,524
- And what sort of animal do you think it is?
- It will be an amphibian.
278
00:25:48,007 --> 00:25:51,795
Stan has now made
many new discoveries in this quarry,
279
00:25:51,647 --> 00:25:56,198
but this, one of his most recent,
is the most important of all.
280
00:25:56,447 --> 00:26:01,521
Its body is twisted, but it's possible to imagine
the bones in a more life-like position
281
00:26:01,727 --> 00:26:04,844
and then to clothe them
with muscles and skin.
282
00:26:05,087 --> 00:26:11,765
This seems to be not only a completely
new species but, at 380 million years old,
283
00:26:11,807 --> 00:26:16,244
the earliest reptile yet discovered
by about 40 million years.
284
00:26:22,767 --> 00:26:28,637
Finding any specimen may be only
the beginning of a long process of research.
285
00:26:29,007 --> 00:26:34,081
Preparing it can alone take months,
and it's a highly skilled job.
286
00:26:34,287 --> 00:26:39,566
In the Natural History Museum in London,
a whole laboratory is devoted to the work.
287
00:26:39,567 --> 00:26:42,445
All kinds of different techniques are used:
288
00:26:42,447 --> 00:26:49,125
air blasting with sand,
grinding with dental drills, chipping with chisels.
289
00:27:00,687 --> 00:27:03,565
Sometimes the work is so delicate and detailed,
290
00:27:04,047 --> 00:27:07,926
it has to be done with needles
under a binocular microscope,
291
00:27:07,887 --> 00:27:11,197
taking away the matrix grain by grain.
292
00:27:15,527 --> 00:27:20,965
When a lot of rock has to be removed,
rather more vigorous techniques can be used.
293
00:27:22,727 --> 00:27:27,721
One whole room is devoted to a method
pioneered by the Natural History Museum,
294
00:27:28,167 --> 00:27:30,158
baths of acetic acid.
295
00:27:30,087 --> 00:27:33,557
- What's this?
- A block of limestone from Queensland, Australia
296
00:27:33,927 --> 00:27:36,600
which contains the remains of a fossil turtle.
297
00:27:36,807 --> 00:27:38,957
- Can we see it?
- Yes.
298
00:27:39,687 --> 00:27:43,316
William Lindsay is an expert
in controlling this process.
299
00:27:43,367 --> 00:27:45,403
The acid eats away the limestone
300
00:27:45,767 --> 00:27:49,885
but has little effect on the fossil bones,
which are chemically rather different.
301
00:27:50,087 --> 00:27:54,717
The bones of this turtle
were already projecting clear of the boulder.
302
00:27:59,087 --> 00:28:03,080
- So how long has it been in here?
- It's almost two years.
303
00:28:03,287 --> 00:28:08,122
- What have you got out so far?
- We've got some parts of shell already removed.
304
00:28:08,167 --> 00:28:12,240
These look like pieces of vertebra.
305
00:28:12,487 --> 00:28:14,364
They're perfect, aren't they?
306
00:28:14,407 --> 00:28:19,686
The advantage of the acid technique
is that it will reveal the most delicate details
307
00:28:19,927 --> 00:28:22,282
that can't be revealed by other methods.
308
00:28:22,327 --> 00:28:25,399
How long will you leave this in this bath?
309
00:28:25,647 --> 00:28:29,481
Possibly almost another year.
310
00:28:29,487 --> 00:28:33,924
Along here we've got a specimen
we're about to start.
311
00:28:34,367 --> 00:28:36,437
This is a block of limestone from Australia.
312
00:28:36,287 --> 00:28:40,246
It comes from a locality where
there have been finds of fossil fish before.
313
00:28:40,607 --> 00:28:43,519
You can see some very small fragments of bone,
314
00:28:43,607 --> 00:28:48,237
and perhaps after a year we'll be able
to reveal something rather more exciting.
315
00:28:48,327 --> 00:28:50,318
OK.
316
00:28:57,127 --> 00:29:01,678
And throughout the next year,
we filmed it, one frame every day,
317
00:29:01,927 --> 00:29:04,646
to record the whole process.
318
00:29:22,647 --> 00:29:27,038
After a year, the matrix
had almost completely been removed.
319
00:29:31,527 --> 00:29:34,246
This 110 million-year-old fish
320
00:29:34,407 --> 00:29:38,923
had obviously decayed quite considerably
before it was covered by the first layers of mud
321
00:29:39,207 --> 00:29:43,120
so that the bones of its skull
had slipped apart and become jumbled,
322
00:29:43,047 --> 00:29:45,641
but they all seem to be here.
323
00:29:47,247 --> 00:29:52,162
This is one of the fins on the underside
of the body, just behind the head.
324
00:29:52,527 --> 00:29:54,916
Here is the right gill cover.
325
00:29:54,927 --> 00:29:59,125
In front of it, the top of the skull
and the brain-case.
326
00:29:59,247 --> 00:30:03,035
And then the snout,
complete with all the tiniest bones,
327
00:30:03,567 --> 00:30:07,242
and teeth not only in the jaws but in the palate,
328
00:30:07,327 --> 00:30:10,842
a detail that had not been known before.
329
00:30:10,687 --> 00:30:13,724
The next step is delicately
to separate the bones one by one
330
00:30:15,007 --> 00:30:19,125
and then put them back together
as they were in life.
331
00:30:19,327 --> 00:30:23,798
That is like working on a jigsaw puzzle
with several hundred pieces,
332
00:30:23,807 --> 00:30:27,197
without a pattern and in three dimensions.
333
00:30:29,847 --> 00:30:32,520
Mahala Andrews
at the Royal Museum of Scotland
334
00:30:32,727 --> 00:30:38,279
has been doing just this with the skull
of a similar fish prepared in an acid bath.
335
00:30:39,327 --> 00:30:44,401
(ANDREWS) The two pieces
have a moveable joint... there.
336
00:30:44,567 --> 00:30:46,762
That's its nostril.
337
00:30:49,847 --> 00:30:56,400
And you can see how it could flap its cheeks
while it was breathing or eating.
338
00:31:00,407 --> 00:31:03,444
And then underneath there are these deep slots
339
00:31:03,807 --> 00:31:08,562
that go right through
to the skin on the outside of its head.
340
00:31:09,967 --> 00:31:14,279
When the lower jaw was in place -
341
00:31:14,527 --> 00:31:17,439
there's the articulation at the back -
342
00:31:17,407 --> 00:31:22,242
these big teeth at the front
would bite right through the skull
343
00:31:22,687 --> 00:31:25,076
up to the skin...
344
00:31:26,527 --> 00:31:28,199
...like that.
345
00:31:29,967 --> 00:31:34,358
This lump of rock contains
no actual remains at all of an animal,
346
00:31:34,767 --> 00:31:38,555
only the rather baffling spaces
where some had once been,
347
00:31:38,527 --> 00:31:42,805
but even here there's a lot that can
be discovered using the right techniques.
348
00:31:43,047 --> 00:31:46,164
Alick Walker from
Newcastle on Tyne University
349
00:31:46,407 --> 00:31:49,205
carefully fills it with liquid silicone rubber,
350
00:31:49,287 --> 00:31:53,644
pouring steadily and slowly
to avoid trapping air bubbles.
351
00:31:54,087 --> 00:31:56,237
It needs an hour or so to set
352
00:31:56,007 --> 00:32:02,606
and, being flexible, can be pulled out of holes
in which plaster would have stuck irretrievably.
353
00:32:14,167 --> 00:32:17,443
(WALKER) Now that the cast
has been removed from the rock,
354
00:32:17,887 --> 00:32:23,598
one can see a good deal more detail
than one could from the natural mould alone.
355
00:32:23,407 --> 00:32:27,764
The cast shows part of the backbone of a reptile.
356
00:32:28,207 --> 00:32:31,404
Here are three vertebrae.
357
00:32:32,047 --> 00:32:36,165
These are ribs, which are slightly displaced,
358
00:32:36,407 --> 00:32:41,197
and here is one of the series
of small circular bony plates or scutes
359
00:32:41,167 --> 00:32:43,965
which lay in the skin
of the top surface of the animal.
360
00:32:48,887 --> 00:32:51,799
Sometimes you can discover
all kinds of information
361
00:32:52,247 --> 00:32:55,205
without even excavating the fossil at all.
362
00:32:55,127 --> 00:32:59,962
This piece of slate, to the naked eye,
contains nothing more than a slight bulge.
363
00:32:59,927 --> 00:33:05,206
But Johannes Mehl of the University of Erlangen
in Germany uses x-ray techniques
364
00:33:05,687 --> 00:33:09,919
and with them reveals things
that can't be seen in any other way.
365
00:33:30,487 --> 00:33:33,524
The equipment he uses
is specially modified apparatus
366
00:33:33,847 --> 00:33:37,556
that was originally developed
for medical purposes.
367
00:33:44,207 --> 00:33:45,720
(SPEAKS GERMAN)
368
00:33:45,647 --> 00:33:50,163
Ah! Well... Yes, how absolutely perfect.
369
00:33:50,447 --> 00:33:53,757
- A starfish.
- Yes, a starfish. Very well preserved.
370
00:33:53,967 --> 00:33:58,245
(ATTENBOROUGH) Perfectly preserved.
And you can see all the tiny structures here.
371
00:33:59,727 --> 00:34:02,400
(MEHL) They are not visible without x-ray.
372
00:34:02,607 --> 00:34:07,078
(ATTENBOROUGH) Could you actually dig it out?
(MEHL) It's very difficult, I think.
373
00:34:07,367 --> 00:34:09,881
- Because that's very delicate, isn't it?
- Yes.
374
00:34:09,767 --> 00:34:14,716
So you can make it only visible by x-raying it.
375
00:34:15,047 --> 00:34:18,198
The next specimen he showed me
was particularly interesting
376
00:34:18,247 --> 00:34:20,317
because this fossil, a cephalopod,
377
00:34:20,647 --> 00:34:25,562
was an earlier form of those bullet-like
fossils in that quarry in Leicestershire.
378
00:34:25,927 --> 00:34:30,398
It was unusually complete, for it had the remains
of some structures at the broad end,
379
00:34:30,247 --> 00:34:33,000
though I couldn't see exactly what they were.
380
00:34:33,327 --> 00:34:38,959
...the radiograph, and it's amazing to see
that there are some organs preserved
381
00:34:38,887 --> 00:34:45,201
and even the gills, which are
very delicate structures, are seen in the x-ray.
382
00:34:45,607 --> 00:34:48,644
(ATTENBOROUGH) But that's totally new, isn't it?
(MEHL) It's totally new.
383
00:34:48,687 --> 00:34:53,636
(MEHL) Let's see an enlarged photograph
of this x-ray.
384
00:34:53,727 --> 00:34:59,006
(MEHL) You can very well realise the two gills,
they have only two and not four gills,
385
00:34:59,487 --> 00:35:06,040
and this picture shows the first gills
known in fossil cephalopods today.
386
00:35:07,647 --> 00:35:10,161
At a hospital in St. Louis in America,
387
00:35:10,047 --> 00:35:15,041
another extremely advanced piece of medical
equipment is being used to look at fossils.
388
00:35:15,327 --> 00:35:19,161
This is the skull of a 50-million-year-old
badger-like animal.
389
00:35:19,167 --> 00:35:22,921
Computer-aided tomography,
or CAT-scanning, as it's called,
390
00:35:23,287 --> 00:35:27,360
is normally used by surgeons
to plan intricate head operations.
391
00:35:27,687 --> 00:35:30,201
This fossil head is excellently preserved,
392
00:35:30,087 --> 00:35:35,525
but its interior is filled with stone that
neither acid nor anything else can remove,
393
00:35:35,847 --> 00:35:38,441
and it's the internal shape of the brain-case
394
00:35:38,727 --> 00:35:42,766
that researchers Glenn Conroy and
Michael Vannier are particularly interested in.
395
00:35:42,567 --> 00:35:47,357
This skull was scanned
in two-millimetre thin slices,
396
00:35:47,847 --> 00:35:52,318
and then the computer reconstructs
the specimen in three dimensions.
397
00:35:52,167 --> 00:35:57,366
We'll bring up here shortly
the four different views of the skull.
398
00:35:57,927 --> 00:36:03,240
As we look on the left side of the screen,
we are seeing a 3D computer image
399
00:36:03,087 --> 00:36:06,397
of the top of this skull,
with the stone matrix removed.
400
00:36:07,247 --> 00:36:12,162
In this bottom view here, the computer
has made the top of the skull disappear,
401
00:36:12,327 --> 00:36:16,115
so that we are now looking down
inside the brain-case.
402
00:36:17,047 --> 00:36:20,039
There's no way we could determine that
from the original specimen
403
00:36:19,927 --> 00:36:23,920
but the computer can electronically
dissect this specimen,
404
00:36:24,447 --> 00:36:29,157
so it's as if the palaeontologist has taken a knife
and cut this specimen right in half.
405
00:36:30,167 --> 00:36:33,125
The computer has removed the stone matrix
from the brain-case.
406
00:36:33,047 --> 00:36:35,880
Here is a picture
of the brain-case of this animal.
407
00:36:35,927 --> 00:36:41,604
We can also see where the spinal cord entered
the back of the skull, going up in this direction.
408
00:36:41,767 --> 00:36:45,840
So, in a sense, we have a window
into this fossil using this CT technique
409
00:36:46,327 --> 00:36:49,080
that we never would have had previously.
410
00:36:49,207 --> 00:36:54,839
And I imagine you can put them all together
to look at it from any point of view you need.
411
00:36:54,967 --> 00:36:58,357
We can take all these views,
put them together in three dimensions
412
00:36:58,407 --> 00:37:01,285
and then look at them in any desired plane.
413
00:37:04,167 --> 00:37:07,921
So today we no longer need
to appeal to the supernatural
414
00:37:07,847 --> 00:37:10,725
to explain the strange shapes in rocks.
415
00:37:12,167 --> 00:37:16,319
This stone spiral is not, as the people
of Arkansas once maintained,
416
00:37:16,487 --> 00:37:18,682
a corkscrew used by the devil,
417
00:37:18,887 --> 00:37:22,084
but the filled-in burrow
of an ancient kind of beaver.
418
00:37:22,247 --> 00:37:25,284
Fossil hunters proved that
by excavating this one,
419
00:37:25,127 --> 00:37:28,244
which had the chamber
at the very bottom still preserved
420
00:37:28,487 --> 00:37:32,321
and in it the bones of the animal that made it.
421
00:37:38,247 --> 00:37:44,004
This is not the devil's toenail,
it's an early ancestor of today's oyster.
422
00:37:45,087 --> 00:37:49,717
A thunderbolt? No, the internal skeleton
of an animal like a squid,
423
00:37:49,887 --> 00:37:55,200
which had tentacles at one end
and, as we now know, two gills.
424
00:37:58,247 --> 00:38:00,238
Stone snakes?
425
00:38:00,167 --> 00:38:03,796
No, shells from a long-vanished sea.
426
00:38:04,007 --> 00:38:07,124
Such revelations are, perhaps,
even more astonishing
427
00:38:07,367 --> 00:38:11,440
than the myths people invented to explain
the strange shapes they found in rocks.
428
00:38:12,607 --> 00:38:17,920
But finding the remains of animals
is only the beginning of this detective story.
429
00:38:17,887 --> 00:38:21,562
Working out how such animals as this
lived and breathed,
430
00:38:21,727 --> 00:38:27,199
moved and behaved hundreds of millions
of years ago is the next part.
431
00:38:27,487 --> 00:38:31,162
That's what we'll be looking at
in the next programme.