00:00 Wide
& pan of Land Rover driving through quarry
Wide,
Sandstone Quarry, researchers walk into shot
c.u.
and tilt of quarry wall detail
Wide
of above
Guide Voice: 400 million years ago this
sandstone quarry, on the border between England and Wales, was a
river. This would have been a very different landscape then –
probably semi-desert around a wide, shallow water course. These
researchers from the University of the West of England, in Bristol,
are studying the rocks and fossils in this quarry in order to
understand the landscape, plants and animals from that time.
00:22 SOT: Dr. Susan Marriott, Reader in Earth
Sciences, University of the West of England, Bristol
– “These rocks are river deposits from about 400
million years ago and they give us a clue as to what the
environment would have been like at the time. For example, at the
bottom here we see the greenish-grey rocks, those would’ve
formed in quite a fast flowing river but because the rocks are
covered in redder rocks that are much finer grained with different
layering in them. We know that the environment changed - there
wasn’t always a river flowing in this area. So for example
what we can tell is that the river may have moved its position or
it could even have dried up.”
01:06 Researcher
(Lance Morrissey) chipping away at rock wall
Over
shoulder shot – chipping at wall
c.u.
fossil of river fish showing horseshoe shaped head shield
c.u.
fossil of river fish
c.u.
fish model and fossil side by side
Wide
shot, fish model
c.u.
fish model, head shot
Medium
wide, researchers in quarry
Wide,
researchers in quarry
c.u.
hand indicating fish trails on fossilised sandstone
Guide Voice: Fossils have been found in these
rocks of fish that used to swim in the river that flowed here all
that time ago. These fish looked very different from freshwater
fish we know today; one group, the cephalaspids, had a unique,
horseshoe-shaped head shield. These fossils tell us what they
looked like – but we don’t know how they moved; or we
didn’t until very recently.
These fossil fish had a different arrangement of fins from
modern fish and scientists have only been able to speculate as to
how they might have swam – but now the researchers at the
University of the West of England have made a discovery that they
believe will unlock the mysteries of these early fish.
They’ve found the earliest ever fish swimming trails
– marks left in the river sediment by fish as they moved over
and close-to the river-bed.
01:51 SOT: Lance Morrissey, Phd Research Student, School
of Geography and Environmental Management, University of the West
of England – “So here we have the fossil
fish trails which are - their Latin name is “Undichna”
- “Und” meaning wave and then “Ichna”,
meaning trace. So, in their simplest form we see them as a single
sinusoidal trace that’s left here in the rock. This is the
second type of fish trail which comprises these two parallel lines
with these pits or resting marks at the end of them. And then
that’s also seen on this slab here – we have the two
parallel markings here but additionally we have a sinusoidal medial
marking as well. So it’s probably the case that the fish
cruised in to land, left the two parallel markings but also left a
central marking, that here is straight, with its tail. It then
stopped and rested on the sediment and then it decided to swim away
– flicked its tail, leaving the sinusoidal
marking”.
02:56 Animation
of fish swimming – overhead view (x 2)
Animation
of fish swimming – side view
(x2)
Guide Voice: Produced at UWE’s Bristol
School of Animation, this sequence shows how cephalaspids may have
swam, based on the trace fossil evidence. This is an important
discovery as it offers tantalising indications of the behaviour of
these early vertebrates. The fish that made these trails appear to
have used their pectoral fins to rest on the sediment before
“take off” – Is this the start of rudimentary
limbs that would one day walk on land?
03:20 Susan Marriott –
“The sediment deposits we have here are based on land and
one of the important things at this time in geological history was
the emergence of life from a watery environment into a land
environment and what we’ve found here are some fossils and
also some traces and trails of the animals that made them and so we
can make inferences about the environment the animals lived in and
link it the evolution of life on land.”
03:51 Lance
Morrissey–“Certainly back in the
19th and throughout the 20th century, the old
red sandstone is very famous for preserving these fish. So the fish
fossils were certainly well known but the fish trails have never
been recorded from the old red sandstone before.”
04:12 Wide,
Susan Marriott and Lance Morrissey study rock face
c.u.
Susan Marriott
Reverse
angle Susan Marriott & Lance Morrissey
Guide Voice: It’s a significant discovery
– the oldest fish trails ever recorded - offering a new
perspective on one aspect of life from the very dawn of
existence.
04:22 End
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