m i^t'niim.J^M* ■ f

'^-^.

RICHARD FORTES

'There's no way to condense Fortey's glittering book, so filled with insight,
science, history, charm and vyi^^QiuP^^^ read it.' RiCHARD Ellis, The Times

Richard Fortey

is a senior palaeontologist at the Natural History Museum,
London. He is author of several books, including Fossils: A Key
to the Past, The Hidden Landscape which won the Natural World
Book of the Year in 1993 and Life: An Unauthorised Biography
which was shortlisted for the Rhone Poulenc Prize in 1998. He is
a Fellow of the Royal Society.

More from the reviews:

'Astonishing ... A delightful book, mixed autobiography, philos-
ophy and palaeontology, which illuminates understanding of that
critical time in the history of the Earth after the explosion of
multicellular life between five and six hundred million years ago.
There is nothing here to intimidate the non-scientist. It is as good
for reading on the beach as anywhere else . . . One of the best
things about this book is its sense of time. Focussed as we are
on our tiny life spans, the story of the trilobite is a healthy
corrective. Hominids cannot be identified beyond four to six
million years ago, the only surviving human species beyond half
a million years ago. We may be special in our own eyes, but in
longevity the trilobites knock us into one of their beautiful conical
hats.' Crispin Tickell, Financial Times

'Suffused with the experience and affection of a lifetime spent
with these common and attractive fossils ... A gripping, splendid
book.' Michael Taylor, New Scientist

'Delightful and beautifully written, Fortey has an eye for the
world about him that would be envied by some travel writers . . .
interesting and impassioned.' John Gribbin, Literary Review

'In Richard Fortey's capable hands, the humble grey trilobite has
been transformed into the E.T. of the Lower Palaeozoic - a lovable
and highly instructive animal, amply deserving of the enthusiasm
and affection with which it is memorialised in this remarkable
and fascinating book.'
Simon Winchester, author of The Surgeon of Crowthorne

'Fortey has turned his considerable literary skills to bringing the
human dance with trilobites before our eyes . . . wonderful. His
reputation as a first-rate natural history writer will only be
enhanced by this volume.' Niles Eldredge, TLS

'Whether you are stuck in a hot, cross city or tethered to a few
boiling feet of beach, this book will transport you from your
prison. What could be better than a long refreshing swim under
the stars across the outer reaches of space and time.'

Maggie Gee, Daily Telegraph

'Vivid, poetic, highly focussed and uncompromising.'

Philip MacCann, Spectator

'Wonderful.' Marina Benjamin, Evening Standard

'Profound and eloquently argued.' Scotsman

'Fascinating . . . Perhaps only small boys [obsessed] by fossils and
the academic professionals who study them have previously heard
of trilobites. Many more will be enthralled when they have read
Trilobite! ' DouglasPalmer, Glasgow Herald

'This is science as the reinvention of the past.'

Brian Appleyard, Sunday Times

'A splendid book written with so much verve and depth.'

Roger High field, Sunday Telegraph

'The title of Richard Fortey's book has an exclamation point. At
first I thought this was a silly idea; exclamation points belong at
the end of shouts. But after I read Trilobite! I realized why it was
added: without it, potential readers might think that it was just
another book about some long-extinct invertebrates crawling
along the bottom of ancient seas. It needs that exclamation point
to shout that it should be read by everybody, whether you know
what a trilobite is or not. Trilobites are - or were - joint-legged,
hard-shelled creatures with multi-faceted eyes, that endured for
three hundred million years, and died out before the dinosaurs
even made their appearance. How these fascinating creatures
began is one of the great mysteries of evolution. The first known
trilobites, from the Early Cambrian, five hundred and forty mil-
lion years ago, were already fully formed, and had a sophisticated
visual system - the first known eyes . . . This is the way science
should be written: so engagingly that it makes you forget that
you're actually learning something (actually, you're learning a
lot), and carrying you swiftly from page to page so that before
you know it, you've let the kettle boil over and you're at the end,
where the "suggesting reading" list shows you that Fortey has read
practically everything about trilobites so that he could condense it
here for you, and make you feel that if it's not too late, you'd
better call him up at the Natural History Museum and see if he
needs an assistant in the trilobite section. If I had five thousand
words I couldn't do Trilobite! justice. There's just no way to
condense Fortey's glittering book so filled with insight, science,
history, charm and wit. The book - every one of its two hundred
and fifty-five pages - speaks brilliantly for itself You must read
it!' Richard Ellis, The Times

'Fortey has transmitted his excitement, knowledge and enthusi-
asm to the page . . . this is required reading.'

Hugh Warwick, BBC Wildlife

ALSO BY RICHARD FORTEY

Fossib: A Key to the Past

The Hidden Landscape
(Natural World Book of the Year 1993)

Life: An Unauthorised Biography
(Shortlisted for the Rhone-Poulenc Prize)

TRILOBITE!

Eyewitness to Evolution

RICHARD FORTEY

Flamingo

An Imprint oj \\irpcr(lo\\\t\sPublishers

Flamingo

An Imprint of HarperCollinsPwfc/ii/iers
77-85 Fulham Palace Road,
Hammersmith, London w6 8ib

www.fireandwater.com

Published by Flamingto 2001
987654

First published in Great Britain by
HarperCollinsPwWzs/ier5 2000

Copyright © Richard Fortey 2000

Richard Fortey asserts the moral right to
be identified as the author of this work

Author photograph by Catherine Eldrige

ISBN o 00 655138 6

Set in PostScript Linotype Minion with Photina display

by Rowland Phototypesetting Ltd, Bury St Edmunds, Suffolk

Printed and bound in Great Britain by
Omnia Books Limited, Glasgow

All rights reserved. No part of this publication may be
reproduced, stored in a retrieval system, or transmitted,
in any form or by any means, electronic, mechanical,
photocopying, recording or otherwise, without the prior
permission of the publishers.

This book is sold subject to the condition that it shall not,
by way of trade or otherwise, be lent, re-sold, hired out or
otherwise circulated without the publisher's prior consent
in any form of binding or cover other than that in which it
is published and without a similar condition including this
condition being imposed on the subsequent purchaser.

FOR MY MOTHER

Contents

ILLUSTRATIONS XI

PLATES xiii

PREFACE XV

I Discovery i

II SheUs 24

III Legs 48

IV Crystal Eyes 79
V Exploding Trilobites 114

VI Museum 139

VII A Matter of Life and Death 152

VIII Possible Worlds 182
IX Time 209

X Eyes to See 246

ACKNOV^LEDGEMENTS 257

SUGGESTIONS FOR FURTHER READING 259

INDEX 261

Illustrations

Drawing of the giant trilobite Paradoxides by Philip

Lake. 20

The anatomy of a trilobite. 28

Spines recovered from trilobites from the Ordovician

of Virginia, USA. }y

'Flatfish' figured in Philosophical Transactions of the

Royal Society by Dr Lhwyd (1679). 45

Fantasy trilobite from J. S. Shroeter (1774). 50

Charles Doolittle Walcott. 54

Walcott's first attempt to show the limbs of trilobites

Ceraurus. 58

Modern reconstruction of the branched limb of

Triarthrus. 58

Professor Beecher's reconstruction of Triarthrus from

the underside, showing branched limbs and

antennae. 62

Legs of Phacops. 68

The workings of a trilobite's eye. 92

Trilobite eyes. 99

Clarkson and Levi-Setti's illustration of the workings

of the highly refractive bowl inside the lens of

Phacops. 103

Reconstruction of the giant-eyed Opipeuter. 106

Free-swimming Parabarrandia. 110

Olenellus. 121

Anamalocaris as reproduced in Steven J. Gould's

Wonderful Life. 132

Place of trilobites in the emergence of animals in the

early Cambrian era. 135

Tray of trilobites from the vast collection in the

Natural History Museum. Photographed by

Catherine Eldridge. 141

XI

trilobite!

Horseshoe crab Limulus, now regarded as the closest

Hving relative to the trilobites. 151

Rudolf Kauffman. 160

Smallest trilobite, AcanthopleureUa. 169

Ken MacNamara's time shifts diagram. 172

Head and tail of Mucronaspis. 176

Gerastos, Ditomopyge and an enroled Symphysurus. i8o

Early Ordovician world, as revealed by the trilobites. 192

Ogyginus. 196

Ordovician Gondwana from a polar projection. 201

Trilobite moult, Paradoxides. 213

Joachim Barrande. 214

Growth of Cambrian trilobite, Sao hirsuta. 216
Electron micrographs of protaspis larvae of Cybelurus. 218

Ontogeny of Shumardia. 222
Sir James Stubblefield en route to Shetland and

Orkney. 224

Trilobite tracks. 226

Fieldaspis. 230

Elrathia and the tail of Drepanura. 233

Dicranurus. 235

A trident-bearing trilobite, as yet unnamed. 253

Spiny trilobite Kettneraspis. 255

Xll

Plates

SECTION ONE

1. Dr Lhwyd's 'flatfish', now known as Ogygiocarella debuchii.

2. Silicified trilobite headshields.

3. Bumastus.

4. Radiaspis, a fantastically spiny trilobite from the Devonian rocks
of Morocco.

5. Dalmanites, one of the first trilobites to be discovered.

6. X-ray of Phacops.

7. Olenoides serratus from the Cambrian Burgess Shale.

8. Hypermecaspis, showing small headshield and long thorax.

9. 'Graveyard' of Leptoplastides.

10. Olenellus, one of the oldest trilobites from the Lower Cambrian
rocks.

11. Tiny, blind Agnostus pisiformis.

12. The elegant Isotelus from the Ordovician of New York State.

13. Blind, medallion-like trilobite Trinudeus fimbriatus.

14. Head of trilobite Protolloydolithus, related to Trinudeus.

15. Giant-eyed trilobite Pricydopyge.

16. Silurian trilobite Calymene, from Gotland, Sweden.

17. Antique gold brooch with Calymene as the centrepiece.

18. Lateral view of perfectly preserved enroled Phacops.

SECTION TWO

19. Crotalocephalus.

20. Acanthopyge, a trilobite the size of a crab.

21. Thysanopeltis, a relative of Scutellum.

22. Cluster of five Cyphaspis.

23. Griffithides, from Carboniferous rocks of Indiana, USA.

24. Paraharpes.

xm

trilobite!

25. Cnemidopyge, a close relative of Ampyx.

26. Three blind trilobites, Conocoryphe.

27. A strawberry-headed trilobite of the Silurian period, Balizoma
varioslaris.

28. Pagetia, a diminutive, flea-sized trilobite.

29. Selenopeltis, with enormously elongated genal spines.

30. Moulted cast-off exoskeleton of Leonaspis.

31. Sao hirsuta from the Cambrian of Bohemia.

32. A plate from Barrande's magnificent work on the trilobites of
Bohemia.

33. A piece of Cambrian 'swallow stones' from Shandong, China.

34. Fantastically spiny trilobite Comura, from the Devonian of
Morocco.

References in the text to figures refer to images reproduced in the
plate sections.

XIV

Preface

I have been enthralled by trilobites for more than thirty years.
This book is both my homage to them, and an attempt to convey
to others something of the pleasure that their study has given to
me. In the process, something of the scientific method may be
revealed. My last book w^as a biography of all life, from bacterium
to mankind, in which the trilobites were passed over in a page
or two. Now I have the chance to turn the focus the other way
and to allow my favourite animals to tell their stories in the detail
they deserve. Even so, I am as conscious of what I have had to
leave out as of what I have been able to include. History can
never be told completely, and three hundred million years of
history is bound to be more of a precis than a narrative. I wish
to persuade the reader of the excitement of recreating vanished
worlds, and of seeing ancient seas through the eyes of the trilo-
bites. This is not an academic study, rather, it is an incitement
to discovery.

London October 1999

XV

Discovery

Out of season, the bar of the Cobweb Inn at Boscastle is everything
a pub should be. There is a low, heavily-beamed ceiling hung with
antique bottles, and a plain floor which is a jigsaw of flagstones.
Photographs of the local women's darts team hang on the wall,
alongside framed, faded newspaper cuttings which record in print
the several virtues of the inn. A log fire gives out rather more
heat than is needed. There is no music save the low buzz of rich
vernacular; in November, no Londoner ventures to the North
Cornwall coast. The Cobweb is a slightly scruffy, comfortable old
place, where you can talk if you need to, but if you feel like saying
nothing you can just watch the flames in the hearth, and nobody
will think you odd if a smile plays on your lips. It takes an effort
of will to leave the dark, comfortable, nourishing womb of the
inn, and emerge, blinking, into the bright world outside; but leave
I must, because I have to find Beeny Cliff before the light fades.
It can be dangerous out on the cliffs after nightfall.

Boscastle is tucked into a cleft on the wild northern coast of
the long peninsula that completes south-west England, and it is
built around a narrow harbour where the River Valency cuts
down to the sea. It is an ancient place, where the cosmetics of
the tourist trade - Witchcraft Museum and knick-knack shops -
have not quite succeeded in smothering a character that was born
of slate and hardship. At one time the town comprised almost

trilobite!

nothing but inns serving miners and seamen, of which the Cob-
web is a survivor, and you can still imagine a dozen different
signs advertising their wares all along the crooked street that leads
to the haven. The houses are former inns, prettified with features
that fail to disguise their boozy origins. The rough local stone
gives the buildings their character. Even the Witchcraft Museum
is a cottage with an ancient roof that sags crazily under the weight
of Cornish slates. On this day the harbour is almost deserted,
and I can imagine the place as it must have looked when the
poet and novelist Thomas Hardy visited it as a young man, more
than a century ago.

I leave the town on the northern side of the harbour where
the path zig-zags up the side of the steep valley. There are gorse
bushes which even at this time of year cheerfully wave sprigs of
yellow pea flowers. Small birds secretively flit across the path -
a wren and some stonechats - as if inviting me onwards. From up
here I can see piers guarding the long, narrow harbour entrance,
barriers that were already ancient when the first Elizabeth was
on the throne. A cold breeze makes me wish I had put on an extra
sweater, but I have luckily caught an interval between showers.
Suddenly, I climb high enough to see the sea. This is one of those
days when the furthest horizon is obscured in mist, as if the sea
went on for ever. It is not stormy weather, but I can hear the
growl of the surf smashing against cliffs, which weave in and out
to the south, one after another, sheer to the sea. A white surf-line
marks the junction:

With its long sea lashings
And cliff side clashings

as Hardy described this coast. The cliffs are dark, almost black,
while the sea is strangely heavy, wrinkled like a pachyderm, so
that only the lazily shifting white line of breakers serves to animate
the prospect. The town in its secret valley has quite slipped from
view; the solitude is absolute. I shelter from the breeze behind a
wall, which is overgrown with rounded tussocks of sea campion

DISCOVERY

and thrift. It is constructed mostly from blocks ofslate; curiously,
the slate slabs are placed vertically, so that they look like books set
on their edges, pages towards you. I am accustomed to different,
horizontally-built stone walls around Oxford. The pattern is
broken by occasional piers incorporating angular blocks of white,
coarse-looking vein quartz. The artisans who buUt these walls
knew their rocks. Slates stacked vertical will let the rainwater (and
there is plenty in Cornwall) drain rapidly away, parallel to the
way the rock naturally splits. Rubbly quartz is indifferent to all
weathers and makes for obstinate pillars. Both rock types are now
decorated with a leafy, frilly form of green lichen, which softens
every stony outline in such a damp climate.

Now that I study the cliffs I can see that they, too, are made
of the same black slates. This is why they seem so forbidding, so
stern and dark. In places they are beetling (a word which only
seems to apply to brows and cliffs) with teetering overhangs,
fissured, and with obviously dangerous crags. These cliffs are a
hymn to vertigo: 'haggard cliffs, of every ugly altitude . . .' I pay
careful attention to the narrow and slippery path; there has been
a lot of rain recently, and one foolish step might have serious
consequences. Tumbledown stone walls indicate that fields
formerly extended very close to the top of the sheer edge, but
now there is only a steep grassy slope between the walker and
the airy heights where razorbills and fulmars wheel on the wind.
The few, stunted trees on the slopes lean away from the fall as if
their branches stretched in horror from the tumbling edge.

By the time I reach the top of Pentargon Bay I have some feeling
for the geology. The dark rocks displayed on the inaccessible cliffs
have surely suffered in a great vice of Earth movements, for they
are tilted and crimped. No strata follow a straight line, instead
they take off on a convoluted journey of their own. On the far
side of the bay I can see a fissure that extends vertically from
cliff edge to sea, which has been excavated by the elements over
millennia. This is certainly a fault - a great fracture through the
black rocks - a dislocation which must have once made the Earth

trilobite!

shudder and tremble. Faults are the visible signatures of
earthquakes, sealed for eternity in the rocks. The whole coast
must have been gripped by a mighty upheaval causing the strata
to crack and buckle. The evidence of a prehistoric paroxysm of
the crust is imprinted on these heights.

Look harder, and evidence of tectonism is everywhere. Not far
from the fault a stream follows a narrow valley which has been
excavated along another plane of weakness in the rocks. Where
the stream reaches the sea its valley is cut off abruptly at the cliff,
and the brook suddenly plunges into a waterfall two hundred
feet above the sea, where it is whipped up by the breeze into
spray. Near the water-line there are caves and smaller crevices
which have been excavated by the probing sea. Even on such a
calm day I can hear the suck and cough of waves assaulting the
slates, picking out the weakest spots where folds have cracked the
strata, marking each small fault with a chasm or a hole. From
time to time a wave rushes into a cave compressing the air within
it - which then recoils with a report. It makes a sound like
distant cannon fire, an irregular salvo fired in an orogenic war.
Imagine the battery on a stormy day. Now it is possible to compre-
hend how thousands of years of erosion have eventually isolated
stacks and islands, like Meachard off Boscastle harbour. In time,
these outposts of land will be worn quite away and returned to
the sea. I can identify^ white quartz in the matrix of the gloomy
cliffs, as clearly as scribblings of chalk on a blackboard. There is
even a patch where the quartz trace shows the strata to have been
folded over completely - turned upside down. I can only speculate
on the massive forces which have treated solid rock with such
disdain. Thicker masses of quartz are aligned along the faults.
Squeezed from the rock like serum from a wound, it congeals in
the cracks. This must have been the source of those large lumps
in the stone walls. Elsewhere, it fills in voids in stressed rock like
some kind of mad spaghetti. Ultimately, though, quartz is tougher
than slate, and survives as pebbles long after the country rock
has been eroded away. I would be willing to wager that some of

DISCOVERY

the rounded pebbles on inaccessible Pentargon beach far below
me are made of quartz. They wiU outlast these cliffs, and - who
knows? - maybe they will outlast the human species.

The sooty shales and slates were once soft muds - sediments
- which accumulated deep beneath the sea. Time has transformed
them: hardened them, elevated them hundreds of feet above pre-
sent sea level, and folded them. But how much time?

Where I am standing now, close to the edge, there is a notice
in red letters: Caution! Cliffs are liable to cracking. Take extra care.
And it's true. A stack of shale is teetering outwards into the void.
It is hard to escape a shiver of apprehension as you imagine the
block tumbling over and over to smash to pieces far below. The
next haven up the coast is called Crackington, the name encapsul-
ating the precariousness induced by erosion.

I have a geological memoir for the Boscastle area tucked into
my jacket pocket. From the geological map which sketches out
the pattern of the outcrops of the rocks I can see something of
the tectonic agony which is so patent in the cHffs: rock formations
twist and turn over the mapped ground, which is criss-crossed
by faults. I can identify exactly where I am standing, on the
outcrop of the Boscastle Formation; in the dry language of science
the slates are described as early Carboniferous (what in the US
would be called Mississippian). This corner of the world has an
extremely ancient origin, older than mammals, older even than
dinosaurs. These black slates would already have carried their
contorted signature as a guarantee of antiquity when Tyranno-
saurus was king of the hill. When they were first laid down there
were only tree ferns and cockroaches and cumbrous amphibians
on land. Can there be a better place to reflect upon the vastness
of geological time?

The erosion which I can both see and hear is ineffably slow. I
could stand here all my hfe and notice little difference to the
cliffs. Maybe a chasm excavated along a fault might seem subtly
darker as its girth increased after an exceptional storm. Perhaps
a rock fall would leave a scar cleared of campion and grass. But

trilobite!

I am certain that when Thomas Hardy stood on this spot he
would have gazed upon a comparable scene; my eyes now see
what his once saw. To be sure, the vegetation would have changed,
but the geological signature of the cliffs would have been legible
in much the same way. How can we conceive of the time needed
to wear away these cliffs to nothing, to convert all the massed slates
into fine silt, quartz veins into pebbles - at first angular, then worn
by the constant shuffling of the sea rounder and rounder, until they
acquire the contours and colours of a hen's egg? Millennia are
irrelevant, species come and go, and still the cliffs stand obstinate
against the inroads of time. Yet given enough time even this
rampart that seems to stand so unflinchingly against the surf will
be reduced to nothing, and the flagstones on the floor of the
Cobweb Inn will return to sediment, joining all the other works
of Man, committed once again to the great cycle of change. Rocks
are eroded to sediment: sediment is hardened to rock; rock is
elevated above sea level by movements of the Earth, transformed
by tectonics; and, thus raised, is once more subject to the assault
of the elements. This is the great wheel of the Earth. If Gustav
Mahler had taken the geological view. Das Lied von der Erde
{The Song of the Earth) would have been a cycle of erosion and
reconstruction endlessly reiterated, enough to try the patience
even of those who admire the most mantric of symphonies.

Cornwall once formed part of a vast mountain chain. It marked
one end of the Hercynides, which snaked through Europe just as
the Alps do today in the south. The patent folding of the rocks
was the result of the slates being trapped in a great tectonic
vice that showed no mercy. Rocks buckled, in an attempt to
accommodate forces that were irresistible. Every tiny ruckle in
the wall of Pentargon Bay is the legacy of suffering under a rule
of tectonics so mighty that no mere rock could stand against the
imperative of crustal stress. When the rocks were folded, structure
was piled upon structure until mountains resulted. Clever geol-
ogists from the University of Exeter, like E. B. Selwood, have
spent years trying to unpick the buckling. They have interpreted

DISCOVERY

this Stretch of coast not as merely folded, but as divided into
great slices of crust which have slid over and past one another.
Squeezed rocks could not absorb the forces by contortion alone,
and were compelled to fracture. To attain equilibrium, vast broken
slabs of rock larger than a parish slid away from the centre of the
forces at a low angle, like the twisted thorn branches leaning away
from the reach of the sea wind. Under the sole of these sliding
masses weaker rocks were folded over and over, crumpled like a
pack of playing cards in the hands of a ruined gambler. Every crack
that was opened up, as the country was ground beneath the
tectonic wheel, would be filled with vein quartz. Now, the eroded
remains of these mountains lay before me. The lichen-covered
stone walls were fabricated from the relics of ancient Alps. The
farmer who orientated the slaty slabs with such care was conniving
with tectonic forces of which he probably knew nothing.

Not many miles to the south, near Bodmin, a granite tor rises
above the general plain. It is reminiscent of some stepped Mayan
pyramid, not least in scale, but is entirely natural. The strange
pile of enormous blocks is what remains behind when granite is
weathered over many thousands of years. Even granite eventually
succumbs to the onslaught of the elements, rain and wind and
frost. But granite endures longer than shale, as I was to see in
St Juliot's churchyard, not far away. Granite, too, is part of the
narrative of the vanished mountain chain, although its source
was utterly different from the shales of the Cornish cliffs. It was
crystallized from a liquid magma, hot and invasive, within the
deep heart of the former chain. Look now: you can see big crystals
of felspar, and maybe the sparkle of mica. These crystals tell the
story of how a mountain chain drives crumpled rocks so deep
into the Earth's crust that they melt, and brew a buoyant, hot
broth of liquid minerals, which once more rises through the
crust to crystallize and solidify as granite batholiths and plutons.
Granite lies at depth beneath the Cornish peninsula, reaching to
the surface under the boggy stretches of Dartmoor and Bodmin.

At the moment of their formation, some of the crystals set in

trilobite!

motion radioactive clocks. Precise modern instruments can now
assess the ticking of geological time as it is recorded by decaying
radioactive isotopes of uranium or potassium (and several other
elements besides) contained in the substance of the crystals. This
method provides the answer to that difficult question: how much
time has passed? The decay rate is known: it is only a matter of
exact measurement and careful calculation to obtain the date of
the mineral's formation. If the Bodmin granites were intruded into
the folded rocks, then it follows that the granites must postdate the
folding. The crystals act almost like eyes that let us see into the
past, to calibrate it, to fix it in our vision. So if the crystal age of
the granite was 300 million years, it fixes our cliffs as older still
- the black slates must have already been folded before the gran-
ites were intruded.

As to the soft muds which were eventually hardened and dis-
torted into the black slates, they were deposited on a Carbonifer-
ous sea-floor, as long as 340 million years ago. Time hardened
them, tectonics twisted them, granites punished them with plu-
tonic heat, long before they came to form the cliffs which now
make sites for the inaccessible nests of fulmars and kittiwakes.
But messages can be passed on from that ancient sea: messages
in the shape of fossils. When the sea-floor was young, shells of
many kinds of animals lay littered among the muds and sands,
just as clam shells can be found stranded on a beach today. These
were mostly ordinary, small creatures, snails and brachiopods and
the like. Their shells became incorporated into the sediment as
more fine mud rained down upon them: mud originated from
the erosion of an ancient landmass, which itself was the product
of a previous cycle of Earth history. This is how the story of the
world turns and turns again. With the passage of time - much
more time - the shells were still there as the muds became deeply
buried, and then hardened into shales when water was driven
out. Perhaps the substance of the shells was augmented by a
subde infihration of minerals at this time. Their original colours
were leached away, a time-change that bleached shells of bright-

8

DISCOVERY

ness, converting them to fossil-colour: they became stony simula-
cra of once-living creatures.

Their journey had only just begun. The Carboniferous sea in
which animals once flourished and left their shelly tokens was
consumed in the engine of plate tectonics. Rocks and fossils alike
- the accumulated legacy of the sea - were passengers on a great
journey. Many of the fossils were doomed to obliteration. They
might be dragged to the centre of the growing Hercynian chain,
fated to be squeezed or baked beyond recognition. They might
be dissolved away. They might be chopped into pieces as the rocks
carrying them recrystallized. Mountains grew over south-west
England, great slabs of country were shrugged sideways in the
melee. Granites insinuated themselves into the depths. As soon
as the mountains were born, they were destined to die by erosion,
so, most likely of all, the fossils could be worn away to an impal-
pable mash that was already on a journey to the next Earth cycle.
We must marvel at the fossil survivors, their chutzpah in the face
of the orogenic enemy.

Sealed in the aftermath of tectonics, the fossils still had to
survive all that followed: the rendering of a mountain chain once
more into the sea. Through more than 200 million years the
Hercynian relic was ground down to its roots. It is certain that
the granites reached the surface at a time when dinosaurs were
still lumbering over the Weald and western Europe, for curious
and distinctive minerals derived from these granites are found
for the first time in rocks laid down in Cretaceous times, about
100 million years ago. Like a geological striptease, veils of rock
were stripped slowly away to ever more fundamental levels within
the ancient chain. Eventually it was stripped naked to its interior,
and the show was over. What I was looking at in Pentargon Cliff
was one of the inner veils, preserved from obliteration, with its
strata still crumpled like discarded chiffon.

What fossils might survive in the dark slates? What miracles
of endurance might they record, what cheating of the laws of
chance? How could a wanderer along this slippery path high

trilobite!

above the everlasting sea truly comprehend what is meant by the
vastness of geological time, even though the evidence is every-
where displayed? Looking down on Boscastle I could almost cap-
ture the historical past - I could 'see' it as one might episodes
from half- remembered movies. It is not difficult to paint a mental
picture of Hardy on this path. Or to envisage, more than a century
ago, filthy slate miners tottering off to the inn of their choice,
with the gentry nearby spry in traps; or to conjure up a bustling
Tudor port with heavy-rigged ships sheltering from the wildness
of the sea in the safe haven, talk of the Armada in the inns,
costumes out of Holbein; I can even visualize an Iron Age farmer's
tilth and husbandry, and the discomfort of a November day like
this in a simple, smoke-filled dwelling. My vision is full of details
rooted in shared humanity, set in bric-a-brac drawn from
memory plausibly arranged. But to quantify the geological time
required for the formation of Cornwall I need to multiply time
a thousand-fold, and then perhaps nearly a thousand times again.
I am as accustomed to writing figures in millions (of years) as is
a Swiss banker (in dollars), yet the lines of zeros do not translate
in proportion. Just as the average working man can understand
exactly the purchasing power of fifty bucks, and fifty thousand
is probably comprehensible, 500,000,000 has an approximate feel
to it - surely, it's a fortune, but what does it mean? A lottery win
of 5 million is a lot, but then, so is 22 million. We reel away from
such vertiginous figures, we can envisage a huge pile of money,
notes piled on notes, but we cannot comprehend its true magni-
tude. If our intention is to see so far into a past of many millions
we shall need to develop a special way of seeing, a spyglass trained
on former worlds. We will need to cultivate an indifference to
magnitude, so that a million years becomes not, after all, such a
long stretch of time. We will need to read rocks and cliffs as if
they were books, and not shudder at the heights.

I have passed the steep side of Pentargon Cliff. Some kind soul
has carved steps to ease the climb, but even so I am out of breath
by the time the path levels off. It now follows a course along the

10

DISCOVERY
Geological Time Scale for Trilobites

ERA PERIOD AGE Ma

250

Permian

290

Carboniferous

Upper Palaeozoic

354

Devonian

PALAEOZOIC +++++++ - - 417

Silurian

443

Ordovician

Lower Palaeozoic

491

Cambrian

545

Precambrian (Vendian)

middle of a steep, grassy slope, and is very slippery. There is a
curious sense of suspension; the sea is far below, but the slope
conceals the vast cliffs which I know must be there. I can still
hear the sea clearly enough: there is an irregular bang! bang! as
waves punish a sea cave along the invisible surf-line, but the great
height I have now reached feels almost illusory, as if I were
ambling along some unspecified stratum floating between sea and
sky. I have reached Beeny Cliff, and I am grateful that the light
has not yet started to weaken. A few drops of rain hit me hard
in the neck. A flock of gulls suddenly rises up from beyond the
cliff edge, buoyed by the updraught and mewling hysterically.
The end of my walk makes me turn up my collar, and shiver.
Beeny Cliff is the scene of a terrifying episode in Hardy's novel

11

trilobite!

A Pair of Blue Eyes. Stephen Knight follows the same path that I
had just completed, in the company of Elfride, the first of Hardy's
complex, closely-observed women heroines. Knight is a man of
scientific bent. Perhaps seeking to display his knowledge - or
maybe just to satisfy his curiosity - he attempts to demonstrate
the contrariwise circulation of the air currents up the face of the
cliff: 'an inverted cascade ... as perfect as Niagara Falls - but
rising instead of falling, and air instead of water'. He leaps on to
the slope below the path, and his hat is caught by the counter-
current; in a foolish attempt to retrieve it he slips down the
appalling incline. He ends up dangling desperately at the edge of
the cliff-face itself; Hardy describes the black slates with some
precision. Here it is that Knight comes face to face with the
subject of this book.

By one of those familiar conjunctions of things wherewith
the inanimate world baits the mind of man when he pauses
in moments of suspense, opposite Knight's eyes was an
imbedded fossil, standing forth in low relief from the rock.
It was a creature with eyes. The eyes, dead and turned to
stone, were even now regarding him. It was one of the
early crustaceans called Trilobites. Separated by millions
of years in their lives. Knight and this underling seem
to have met in their place of death. It was the single
instance within reach of anything that had been alive
and had had a body to save, as he himself had now.

In this bleak spot, where I was gazing out towards the precipice
between the wrinkled sea below and the darkening sky above,
trilobites made a brief appearance in English literature. The path
above Beeny Cliff was where two paths of my own life - trilobites
and writing - uniquely intersected. I felt compelled to visit the
place; and I was not disappointed. The eyes of the trilobite, 'turned
to stone', provided the image I needed to guide the reader through
this book, which will try to see the world through the eyes of
fossils as a means to animate the past. Equally, I was intrigued

12

DISCOVERY

by the difference between the novelist's truth, which has nothing
to do with testabiUty and everything to do with the impact of
the work on the mind and emotions, and scientific truth, which
has everything to do with testabihty, but also with the emotions
of discovery - many of them the stuff of novels.

So to what extent was Hardy telling the truth? Hardy was
writing his novel originally as a serial - he needed to keep his
readers enthralled, episode by episode. Knight's predicament was
a cliffhanger in the most literal sense. How can you have more
suspense than to leave your character exactly suspended? The
trilobite eyes provided a focus for Knight's near-nemesis; while
human eyes - blue ones - provided both the title and emotional
motor for the novel. The critic Pamela Dalziel has noticed how
the plot twists upon 'spying' of one kind or another. The book
is soaked with the implications of sight.

I was interested to see how closely Hardy had observed the
setting for his cliff-hanging episode. Scholars have identified the
location fi'om many details from his early life. While he was still
employed as an architect restoring St Juliot's Church in 1870, he
met his future wife, Emma Gifford, who was the sister-in-law of
the Rector. Locations in the area are rather thinly disguised, and
it evidently lies well to the west of the rest of Hardy's Wessex. A
Pair of Blue Eyes included more autobiographical elements than
his other novels, and perhaps for that reason evidently remained
dear to his heart (he rewrote parts of it many years later). The
height of the cliff itself is rather pedantically described, even as
poor Knight flounders, surely indicating that the young writer
had gazetteers open, and a sharpened pencil in front of him as
he catalogued its statistics: 'proved by actual measurement not
to be a foot less than six hundred and fifty [feet] . . . three times
the height of Flamborough, a hundred feet higher than Beachy
Head . . . thrice as high as the Lizard' (and there is more in this
vein). But what left me in no doubt at all about the site was the
walk I had taken, which was duplicated exactly by the characters
in the novel. Hardy had observed what was evidently the same

13

trilobite!

waterfall plunging to obscurity that I had seen at Pentargon Bay,
'running over the precipice it was dispersed in spray before it
was half way down, and falling like rain upon projecting ledges
made minute grassy meadows of them'. He described the threat-
ening cliffs, with their 'horrid personality' at the same point as I
had seen them on my walk. In many respects passages in the
novel could be described as reportage: he could recognize both
quartz and slate, he recounted physical features in order along
the path, he knew some geology and meteorology. WhUe Knight
clung to the cliff face his mind raced back through geological
time - a series of tableaux of the past succeeded one another in
his desperate mind all the way back to the ancient time of the
trilobites. It is not a bad account, scientifically speaking, of the
succession of life through geological time as conceived about i860.
But now we reach a point at which fiction and description take
off along different paths; perhaps the fascination of the novel lies
in these deviations. Why did Hardy refer to Beeny Cliff as The
Cliff with No Name? The hamlet of Beeny is clearly named on
old maps and he was usually adept at near-synonyms - Camelton
for Camelford, Dundagel for Tintagel. I believe that 'No Name'
adds to the horror and mystery of the place. The same point was
appreciated by Sergio Leone: in his brooding spaghetti westerns
'The Man with No Name', played by Clint Eastwood, was the
anti-hero. Naming is the first way we domesticate our surround-
ings; we would expect the highest cliff along the coast to have a
name. Anonymity is horror. When a series of murders are com-
mitted terror is at its worst while the perpetrator is still unknown:
a case of nameless dread. The fabricator of fiction knew this; this
is where artifice comes in. Hardy liked facts, but he knew also
when to suspend them. The trilobite itself is a convenient fiction.
The Carboniferous rocks on this part of the Cornish coast have
yielded no trilobites. The rocks are of the right age, so there is
no theoretical objection to finding trilobites there. Fossils are very
rare from such tectonically tortured rocks. Enough have been
found - precursors of ammonites, clams, microscopic fossils -

14

DISCOVERY

to establish the geological age, but trilobites are not among them.
I would be absolutely delighted to receive a trilobite from a
collector lucky enough to hammer one out of these unpromising
strata; it would be of appreciable scientific importance. Hardy
placed the fossil in the right geological setting, but the finding of
a trilobite is an invention. He needed the trilobite to stare out
Stephen Knight. As readers of fiction we relish his use of this
particular fossil, 'but a low type of animal existence', as heighten-
ing the drama of the situation. It matters not a jot that the
occurrence is fictional, even though the rest of Hardy's account
is an almost photographic reproduction of a real scene. A scientist
would be appalled if one of his colleagues invented such an
occurrence, for science trades on the truth - nothing but the
objective fact. The truth of the artist can recombine the facts of
the world in the service of creation, but the scientist has a different
duty, to discover the truth lying behind the facade of appearance.
Both processes may be equally imaginative.

As for Mr Knight, he escaped his predicament thanks to a rope,
but a rope desperately manufactured from Elfride's undergar-
ments. It is a turning point in the novel, symbolizing a change
in the relationship between a flawed man and an unusual woman.
And we are not compelled to wonder whether such an episode
was fact or not, because it is woven into the fabric of a novel.

I left Beeny Cliff by climbing up the steep steps to Fire Beacon
Point, a wild bluff commanding views of the whole Hercynian
coast. It may have acquired its name as one of numerous
beacons on which fires were lit to warn of the approach of an
armada. Now, there is only a bench at the top dedicated to the
memory of Paul C. Heard, but I thanked Mr Heard's relatives
for the chance to rest and regain my breath. I turned inland,
following an old, walled track. I wanted to see the parish church
of St Juliot on which Hardy had worked. It is perfectly set on a
sheltered hillside, and behind it a track leads out directly across
fields upon which sheep graze unhurriedly. Despite the setting,
there is something depressingly foursquare and Victorian about

15

trilobite!

St Juliot's - possibly the fault of Hardy's restoration - including
a rather dumpy tower with unnecessary castellation. It is as if the
site deserved something much more distinguished to live up to
its associations. After all. Hardy wrote that 'much of my life
claims the spot as its key'. Surely it is an ancient holy place, which
the church fails adequately to honour. In the graveyard there are
several 'Jollows' - possibly a bastardized version of the name
Juliot - the kind of family that must have grown out of the local
soil as surely as wind-blown gorse. Inside the church there is a
notice informing the visitor that most of the church plate has
already been stolen. There was nothing to induce me to linger.
But as I left I saw the Celtic crosses, more ancient than the
church itself. Close by the gate one crudely shaped column as
high as a man stands sentinel; its apex is sculpted into a disc,
and you might expect to find some sort of face hewn upon it,
but instead there is a schematic cross. Unlike the slatey grave-
stones, these upright crosses are made from granite. They will
endure when all the inscribed memorials to Jollows have
crumbled into the same soil that long since claimed their bones.
The granite was derived fi-om one of the igneous intrusions into
the bowels of the Hercynian mountain range. Maybe the blocks
were derived from Bodmin or Dartmoor, but whatever the source
their hewers knew about permanence. Each monument acknowl-
edges the vast span of geological time, the durability of stone
compared with a human lifetime. Each is a symbol of the crossing
of human intention with tectonic history - the same history that
placed Hardy's plausible but fictional trilobite into Beeny Cliff.
The discoidal apex of the cross is like an eyepiece with a view
clear back to the age of the tree ferns and lungfishes. This, after
all, may have been what I wanted to discover on a chilly November
day in Boscastle. I felt a curious elation, even as the icy raindrops
began to refresh the lichens that alone could derive sustenance
from incorruptible granite - set solid ever since trilobites had
patrolled the shallows of a vanished ocean.

16

DISCOVERY

If you can have love at first sight, then I fell in love with trilobites
at the age of fourteen.

The peninsula of St Davids forms the south-western promon-
tory of South Wales, extending westwards like a miniature version
of the Cornish peninsula where Hardy, too, encountered love.
Like Cornwall, it is a region of spectacular and ancient cliffs,
while inland the scenery is flat and characterless. There are little
coves here, too, with names like Solva and Abercastle, formerly
wild and remote fishing villages, but now spruce with whitewash
over the rough stone. But the cliffs are as wild as ever they were,
and displaying rock folds as convoluted as anything in Cornwall.
A walk along the coastal path parades one rock formation after
another, delineated by contrasts in colour and texture: here mass-
ive yellow or purple sandstones plunge like naked ribs into the
churning foam, there a group of contorted dark shales zig-zag
up the cliffs like some sort of beserk concertina. In Caerfai Bay
there are bright red shales, looking improbably pert in a world
of dun geology. All of these rocks are still more ancient than
their Cornish counterparts. They date from the Cambrian period,
the oldest of the shales having been laid down as muds beneath
the sea something like 545 million years before the present. This
is getting back to the beginning of things, to a time before there
were any plants on land, to a time before any kind of backboned
animal existed. Yet there were already trilobites to witness this
nascent world. These trilobites were 200 million years older than
Thomas Hardy's invented fossil (or, I should say, its real equiva-
lents) - a span a hundred times longer than Man's brief tenancy
of this planet. This was the time I explored with a coal hammer
at a period of my life when my voice had just turned unreliably
falsetto and baritone by turns. While others discovered girls, I
discovered trilobites.

I had marked the presence of fossils on a local map. They were
described as the oldest fossils in the British Isles. What could be
more irresistible? There was something extraordinarily exciting
about tapping into a vein of such prehistory. The top dressing

17

trilobite!

of the landscape of human tenancy was stripped away to reveal
some deeper reality, layer after layer of geological time unpeeled
in my imagination. While my long-suffering mother knitted or
read, I beat the rocks at Nine Wells and Porth-y-rhaw*. These
were places where the rocks were accessible by foot and could be
broken by sheer effort. I did not even have a proper geological
hammer. The fever of discovery was upon me. I learned how to
break the hard rock so that it split in the same direction as the
former sea floor - this way I was more likely to retrieve something
recognizable. It was clear that tectonic forces had tipped the strata
vertically. I had to scrabble to dislodge reasonable-sized blocks
for breakage. I ignored the sharp pieces of gorse that speared the
backs of my hands. Time had made the rock both hard and
brittle: it seemed to want to break anywhere but in the right
direction. On the broken surfaces there were scraps and fragments
of what might, or might not have been the remains of past life:
black patches, a little shinier than the rest of the rock. Then, at
last, I found a trilobite. The rock simply parted around the animal,
like some sort of revelation. The truth is that the fossil itself had
rendered the rock weaker: it was predisposed to reveal itself,
almost as if it desired disclosure. I was left holding two pieces of
rock: in my left hand the positive impression of the creature itself
(known as the part); in my right hand the negative mould which
had once comprised its other half (the counterpart); the two
together snuggling up to survive the vicissitudes of millions of
years of entombment. There was a brownish stain on the fossil,
but to me it was no disfigurement - surely what I held was
the textbook come alive. Drawings and photographs could not
compare with the joy of actually touching a find which seemed,
in the egotistical glow of boyhood, dedicated to yourself alone.
This was my first discovery of the animals that would change
my life. The long thin eyes of the trilobite regarded me and
I returned the gaze. More compelling than any pair of blue

* Both these sites are now legally protected from hammering, although they were not
at the time of my schoolboy excursions.

18

DISCOVERY

eyes, there was a shiver of recognition across 500 milUon years.

I would one day learn that the trilobite had a name, Para-
doxides. When we first exchanged glances I knew nothing of
classification or nomenclature, and it did not matter to me: there
was plenty of time to learn more. What I held was a specimen
that fitted comfortably into the palm of my hand. It was clearly
divided along its length into three lobes - a convex central portion
and to each side of it identical, but slightly flattened, areas. These
were the lobes implied by the name - trilobite. The whole animal
seemed to bulge towards one end. I knew, by some principle
which I could not articulate, that the wider end was the head of
the animal. And of course upon this head there were the eyes.
Despite the unfamiliar conformation of the fossil, I knew that
eyes must always belong on heads. So despite the exoticism of
the fossil there was already a common bond between me and the
trilobite - we both had our heads screwed on the right way. I
could see that the body was subdivided into a number of little
divisions - or segments, as I would learn to call them. Then there
were cracks running across the body. These had nothing to do
with the original structure of the animal, rather they were testi-
mony to the long journey through geological time that the Cam-
brian creature had travelled before it fell apart under my hammer
blow. They were joints in the fabric of the rock itself, the scars
of an adventure that might have seen the trilobite eroded into
oblivion or obliterated in the vice of a thousand tectonic
accidents.

This book grew out of that first encounter. I want to invest
the trilobite with all the glamour of the dinosaur and twice its
endurance. I want you to see the world through the eyes of
trilobites, to help you to make a journey back through hundreds
of millions of years. I will show that Hardy's description of the
trilobite as 'but a low type of animal existence' was hardly just,
but that his placing the animal at the centre of a drama of life
and death might have been nearer the mark. This will be an
unabashedly trilobito-centric view of the world.

19

trilobite!

A drawing of the giant trilobite Paradoxides by Philip Lake pub-
lished in 1935, from the same Middle Cambrian rocks in western
Wales that yielded the first specimen to my schoolboy hammer.
For a photograph of Paradoxides, see page 213.

20

DISCOVERY

For trilobites have been witnesses to great events. Stephen
Knight might have read from the trilobite's stony eyes that the
predicament of a mere individual meant nothing. They have seen
continents move, mountain chains elevated and eroded to their
granite cores, they have survived ice ages and massive volcanic
eruptions. No living thing can disengage itself from the biosphere,
and trilobites followed the same pattern: their history was also
shaped by the events they witnessed. When strangers express their
surprise that it is possible to devote a lifetime to studying extinct
'bugs' I remind them of how much has happened in the last few
thousand years and invite them to imagine what it is to be a
historian of dozens of millions of years. We are doomed to know
so little, like fishermen trying to understand an entire ocean by
throwing in a few baited handlines. And if anyone wonders how
it is possible to invest such devotion in a group of organisms
which died out long ago as a result of who-knows-what inad-
equacies, there is an obvious answer. Trilobites survived for a
total of three hundred million years, almost the whole duration
of the Palaeozoic era: who are we johnny-come-latelies to label
them as either 'primitive' or 'unsuccessful'? Men have so far
survived half a per cent as long.

There are accounts of scientific research that present the story
of discovery as a series of glittering prizes that must be won
by the most muscular intellect; this is science as a version of
trial-by-combat. Or else scientific research is contained in a
metaphor of a journey into uncharted territory, as expressed
by Robert Louis Stevenson (in Pulvis et umbra): 'science carries
us into realms of speculation, where there is no habitable city for
the mind of man.' It is certainly true that there are races to be
first in science and that a few massive minds venturing into
'realms of speculation' command the most attention - and they
deserve it. Such models of scientific progress are typified by
mathematicians and physicists, beautifully elaborated by Karl
Popper in Conjectures and Refutations. Nonetheless, as a descrip-
tion of much of scientific endeavour, both the combative and

21

trilobite!

the adventurous-speculative views are flawed. Many scientists -
perhaps most of them - are a curious species for whom the
pleasure of finding out is at least as important as the size of the
goal. He or she is often a co-operative creature, comfortable with
the happy exercise of innate ability, and if a momentous discovery
comes it may arrive unexpectedly, like an unanticipated legacy.
The unique property of the scientific endeavour is that so many
of the regular footsoldiers contribute to the victory. Unlike a
poetaster whose burblings are destined for true oblivion while
the creations of a Keats survive, even a minor scientist might well
make a permanent contribution to a famous campaign - an
uncelebrated private who did not die in vain.

Even the most singular fields of scientific inquiry relate in
subtle or unexpected ways to larger questions. We shall see that an
apparently self-contained and esoteric occupation like the study of
trilobites has contributed to mighty debates about the origin of
new species, or the nature of major features of evolution, or the
distribution of the ancient continents. Those who started with a
deep desire to know more about the details of life habits of
vanished animals - out of sheer curiosity - may suddenly realize
that the detailed knowledge they have accrued relates to some-
thing different and more general: something as grand as the
structure of an ancient ocean or the arrival of an asteroid on
Earth.

I believe that a more accurate image for the way much of
science works might be a series of interconnecting paths. Each
one has its own interests and delights; sometimes we know where
a path leads, on others we are taken by surprise by twists and
turns. And where there are intersections with other paths there
can be unanticipated new directions which may lead to wholly
unexpected views. Like Stephen and Elfride on the path above
The Cliff with No Name there may be a crucial conjunction of
circumstances which changes everything, and something as small
and ancient as a trilobite may be the catalyst for the transfor-
mation.

22

DISCOVERY

This book will follow a few of the paths that led me from that
first schoolboy find. In pursuit of trilobites I shall visit remarkable
places and spend time with remarkable people. Knowledge has
been hard won, and there are heroes whose names are known
only to me and a few of my friends, who deserve wider recog-
nition. There are stories of personal tragedies which have influ-
enced this tale of trilobites. Discovery isn't a simple matter of
'onwards and upwards'. It is imbued with all the tawdry and
magnificent stuff of human lives. The story of that small part of
science which is important to me will illustrate the way this
defining human activity works better than some other accounts
of greater endeavours: like relativity or the first few nanoseconds
of the universe. Sometimes, a miniature gives a better likeness
than a grandiose portrait.

Come and see the world as it once was through the crystal
eyes of the trilobite. We shall find out how trilobites tell us the
pattern of evolution, and how it can be read from the rocks. We
shall discover how faith in trilobites not merely moves mountains
but shifts whole continents. We shall see how cast-off shells can
be re-animated into living animals. We shall understand some-
thing of the origins of the richness of the animal kingdom.
Through trilobites, we shall take possession of the geological past.

23

II
Shells

In 1698 Dr Lhwyd wrote to his correspondent Martin Lister about
the fossils to be found in the limestones around the South Wales
town of Llandeilo: 'the 15th [of August] whereof we found great
plenty must doubtless be referred to the sceleton of some Flat-
Fish.' Lhwyd's 'flatfish' were, of course, trilobites.

When my children were young they used to play a game with
sea shells. Holding a large whelk to one ear they contrived to
'hear' the sea: the distant crashing of waves on the shore, or the
insistent whistling of a gentle sea breeze. Later they understood
that the conch merely amplified the murmuring of the air around
them, but they never forgot the leap of imagination that joined
shell to sea.

Palaeontology is all about listening to what fossil shells have
to say. We have to pay attention to shells, because hard skeletons
made of durable minerals are almost always what fossilizes. With
rare exceptions, the soft anatomy eludes us. Body tissues are food
for predators, or for the agents of decay. Who has not picked up
a crab shell on a beach, and let it go with a cry of disgust, startled
by the pong of putrefaction? Bacteria are everywhere, greedy to
decompose, voracious for those organic molecules manufactured
with vital energy during life - and then yielding up that energy
again to a host of tiny diners, a few thousandths of a millimetre
long. 'Too, too solid flesh' does indeed melt. What remains behind

24

SHELLS

- shells and bones - has little to sustain the ubiquitous bacteria.
Trilobite shells are like those of a dozen or more other kinds of
marine animals, being sculpted from the hard mineral calcite.
Crab shells are composed of calcite, so are those of clams. If
trilobites had not carried their hard shells they would have been
effectively invisible to us, for they would have left virtually no
trace of their former existence. Had the seas teemed with them
as thick as oats in porridge we would have remained ignorant of
their rich diversity. Fossil shells are the cast-offs of life, the tough
bits, the inedible residue. That which was of least interest to other
living animals in life is, ironically, just what generates the interest
of both the scholar and the geologist once it has been transformed
by time into a fossil. To begin to understand trilobites it is neces-
sary to know about their shells.

Even the shell of a trilobite loses something on death. Colour
is the most transient of properties. We know that sea-life today
is a symphony of hues: colours flashed as warning, colours subtly
employed in disguise, colours seemingly just for sheer exuberance.
It is likely that the seas hundreds of millions of years ago were
just as polychromic. Yet colour is the first property to bleed
away in the fossilization process. The fossil world is a pallid
world, which only imagination can revivify. The colours of the
dark trilobites I saw in western Wales were the colours of the
rocks that entombed them, with no indication of the appearance
of the original animals. We can colour them up as we fancy. I
have taken such a liberty with the trilobite on the cover of this
book.

I learned trilobite shell anatomy as a student. The terms that
I heard empowered me, allowed me to place these strange animals
within a field of comprehension. It was curious how learning to
call the head of the trilobite the cephalon seemed to admit me
into the special world of the trilobite lover. Cephalos is the Greek
for 'head' so really we are just replacing one head by another.
All trilobites, I learned, were divided into three portions not just
along their length - the tri-lobes - but also crossways. As I had

25

trilobite!

instinctively recognized from my first trilobite at St David's, the
cephalon v^^as the front portion, the part that looked at me. At
the other end was the tail, which I must learn to call the pygidium
- a Greek word again.

The adoption of classical language is not to be wondered at,
for in the early days of natural history Latin was still the chief
medium of communication between scientists of different nation-
alities. Classics was the sine qua non of the educated classes, the
lingua franca, and not just dropped into any sentence to impress
the reader with the learning of the writer (see sine qua non, above,
but not lingua franca, which isn't Latin). Botanists are still obliged
to write a shorthand Latin description of every new species
(although this may be about to change), something zoologists
have not had to worry about for a hundred years. But classical
terms for bits of anatomy, whether of an animal or a plant, are
more enduring. Medical students curse them even as they commit
them to memory, laymen puzzle over them. They serve as a
continuous link all the way back to the time of William Harvey
and his unscrambling of the circulation of the blood; the terms
last while the concepts around them change. This conservatism
serves a useful function in retaining a language in which specialists
can converse precisely. The first task of the tiro is to master
words. The sign that the beginner has joined the hidden club of
experts is when he can trade technical descriptions with confi-
dence. There is more to it than that, because the applying the
right word is also a guarantee of recognition. The more closely
a natural object is anatomized the closer you have to look, and
the more terms have to be mastered. Latin or Greek, it matters
not, what is important is that a technical term is a shorthand for
learning. Nomenclature is a preface to understanding.

So 1 observed that between cephalon and pygidium there was
the thorax. It is a familiar enough word, even if its use in the
human context is quite different. This portion of the trilobite
was the longest part - at least in those trilobites I studied first.
It was further divided into a number of segments - thoracic

26

SHELLS

segments. (At the height of Steven Spielberg's fame I toyed with
the idea of a movie to restore trilobites to the dramatic centre in
the history of Hfe that they deserve. Perhaps a crazed palaeontol-
ogist reanimates them from the dead using some appropriate
hocus pocus until they rampage unbridled through New York,
savaging scantily clad beauties, and knocking down buildings . . .
that sort of thing. It was to be called Thoracic Park.)

Each thoracic segment was jointed, and connected by a weak
hinge to the one in front and the one behind. Segments form a
linked system, rather like railway carriages in a line. They are all
more or less similar, and connected together by a coupling. If we
had tried to snap the fresh trilobite in two it is almost certain
that it would have snapped between segments. It is the same
principle that makes us divide a lobster shell at the back of the
head. The lack of comparable segments is what makes a tortoise
so impregnable - but also so inflexible. A tortoise trundles along,
lurching over obstacles, and often dies if it happens to tumble
on to its back. There is nothing more ineffectual than a tortoise
foolishly waving its legs in the air in a doomed attempt to right
itself. Not so a segmented animal. When an obstacle is encoun-
tered the segments can shift relative to one another to allow
flexibility: they are articulated, hinged, jointed. The movement
between segments is dictated by the laws of mechanics: this is
why iron plated, alien bugs in science fiction movies look both
mechanical and convincing. Segments really are all about the
articulation of armature. Even when stranded on their backs seg-
mented animals can wriggle upright. To the trilobite a certain
vulnerability was the price of flexibility, and a price worth paying.
The trilobite could move over obstacles, flex and turn, like a train
that needed no tracks on which to run.

Looking closer at the tail - or pygidium - it is clear that this,
too, included a few segments, but instead of being free to articu-
late they are ftised together, forming a shield. In some trilobites
the pygidium is longer than the head, and includes many seg-
ments; in others it is minute. Later I would learn why these

27

TRILOBITE

Cephalon (head)

Thorax

Facial suture
Eye

Free cheek

Glabella
Fixed cheek

Axis

Pleural region

-Cranidium

Pygidium (tail)

The anatomy of a trilobite: a few technical terms, labelled here on Calymene,
allow us to describe almost any trilobite.

differences might be useful to the animal. Both thorax and
pygidium had an obviously convex central portion - the middle
lobe of the trilobite - which, in a rare display of nomenclatural
simplicity, is called the axis. Furrows divide the axis from the
lateral, or pleural., parts. So now I had heard the names to distin-
guish the three lobes of the trilobite: the axial lobe and the flanking
pleural lobes. Each thoracic segment had a pleura on either side.
In my first ever trilobite these pleurae had spiny tips, so I knew
that if I had picked up the living animal it would have felt spiky
in my hand, with that particular kind of unpleasant prickliness
that one gets with handling a langoustine.

As for the trilobite head that first attracted my attention when
I cleaved open the dark Cambrian shale of St David's, that, too,
showed an inflated axial part - the axis of the thorax carried on
and widened forwards into a swollen, and prominent, median
portion. 'This,' our professor said, 'is the most important and
characteristic part of the trilobite - the glabella.' No familiar ring
to this word, it just had to be learned. It had the small advantage
of rhyming with 'umbrella' - and undergraduates are fond of

28

SHELLS

such aides-memoires, even if they are harder to remember than
the original thing to be memorized. The glabella was traversed
by furrows that suggested that there was more than one segment
in the cephalon, just as in the thorax and pygidium. However,
the segments must have been fused together to make the head
end an altogether more robust contraption than the thorax, and
more like the pygidium in this respect. To either side of the
glabella are the eyes, and - believe it or not - they are just
known as eyes. By using such a simple word we acknowledge our
realization of the connection between the student observing and
the object studied. Hardy's 'eyes, dead and turned to stone' looked
across millions of years with a stare of genuine recognition of
like for like.

So in just eight technical terms - cephalon, thorax, pygidium,
segment, axis, pleura, glabella, eyes - it is possible to begin to
embrace the form of these strange animals. To be able to name
the parts introduces a certain familiarity. Further, to be competent
to recognize the glabella for what it is means that it does not
take long to see that one trilobite has a glabella which is quite
different from that of another. With language comes discrimi-
nation. And it is true that every item named is capable of varying
mightily from one species to another: there are those with large
eyes and small, those with long thoraces and short, wide or narrow
pygidia. I was soon to learn that there were thousands of different
species of trilobites and, in the end, I was to become a namer of
new names myself

For now, though, trilobites were hardly more than the jetti-
soned husks of once-living animals. Listening to the message of
the shells was like trying to hear the sounds of a far-off sea, more
remote than childhood. I had begun to acquire a language to
describe what I might be hearing. The reader will need to be
equipped with the same short list of terms in order to follow the
rest of the tale of the trilobite: it is not so difficult to memorize
them. The inventory of trilobite parts that I first learned were
the same bits of anatomy that the original discoverers of these

29

trilobite!

fossils had recognized as long ago as the eighteenth century. These
pioneers were puzzled as well as excited by trilobites: they gave
them names like Agnostus and Paradoxides, which surely reveal
the problems they had with their interpretation. There is even a
Cambrian species called Paradoxides paradoxissimus, which might
be translated from the Latin as 'the most paradoxical paradox' -
more paradoxical than which it is not possible to get.

These early observers soon realized that the shells prised from
the rock were only carapaces, rather than the whole animal. The
trilobite they knew was only the back of a complicated organism.
The shell was nothing more or less than a shield which covered
its upper side - the part which is most exposed to a hostile world.
A shield protects. In old literature it is quite common to find the
cephalon referred to as the headshield - and the pygidium as the
tailshield - and these descriptions are still entirely appropriate.
Tough calcite made the trilobite less vulnerable on its dorsal side,
while its underside, the ventral side, was the sheltered underbelly
where lay the soft anatomy that is so rarely preserved. The trilobite
seems almost pathetically unprotected on its lower side, for the
shell stopped abruptly after being 'tucked under' the edge of the
trilobite in a narrow shelf, or selvage, known as the doublure.
Beyond the doublure there is only a cavity, an absence of evidence.
This is quite different from the tortoise, where the underside is
sealed by a bone shield called the plastron - making it into a
veritable tank. The trilobite is half a tank. There is no living
creature exactly comparable, although if you turn a woodlouse
(or slater) on its back, where their little legs kick and struggle is
the equivalent of the trilobite's body underneath. For many years
what lay beyond the doublure of the trilobite was a mystery -
the trilobite was like a paten without the bread at Eucharist, a
vessel lacking its full significance. You will learn how the mystery
of legs was solved in the next chapter.

I acquired my first trilobite facts from lecturers and professors.
When I was a student it was possible to assimilate most of the
basic elements from textbooks, if you wished, and nowadays we

30

SHELLS

can summon massive inventories of information from the web,
but it still makes a difference to learn directly from a real scholar.
This experience reaches back to a time when the oral tradition
was the only way of teaching - when the young received wisdom
as a favour from the elders. In China, despite the Cultural Revol-
ution, this reverence for the wisdom of the aged endures. When
I was in Nanjing in 1983, 1 was taken to see the grave of Professor
Grabau, a western palaeontologist who almost singlehandedly
introduced modern geological principles into China in the early
years of the twentieth century: he was, so I was told, 'a great
teacher'. The Chinese compliment is such an important one that
it is represented by a special ideogram. It was a simple grave, but
obviously regularly and lovingly tended. I was once briefly
favoured with the status of 'great teacher' myself: I received a
letter from a far eastern student who had evidently learned his
English from Rudyard Kipling and Rider Haggard. 'Oh Great
Palaeontologist!' it began, 'may I sit at your feet?' Those who
know my feet might regard this as unwise, but I was touched by
the faith evinced in the oral tradition.

My own guru was Professor Harry B. Whittington. He is the
doyen of trilobites, the head - the cephalon - of the tribe. He
would teach me to hear the messages of the shells. Somehow, I
had managed to convert an infatuation into a career.

I learned my trade on the frozen ground of Spitsbergen beyond
the Arctic Circle at 80° North, with the Valhallfonna icecap defin-
ing the skyline and an iceberg- clogged sea before me. An amazing
variety of new trilobites was discovered in Ordovician (470 million
year-old) limestones on the northern part of Spitsbergen, and I
was lucky enough to be there when they were found. I collected
rock beds exposed along the shore one by one in the appropriate
order, so as to turn the stony pages of the trilobite diaries in
sequence, tap-tap-tapping my way through my own little piece
of geological time (a mere 10 million years or so). Mostly this
consisted of bashing hard rocks with a geological hammer, until
they were in small pieces on which fragments of trilobite could

31

trilobite!

be seen. Hardened criminals used to be required to do the same
thing before it was banned as inhumane. I loved it. All discomfort
in the harsh climate was set aside in the inspiriting warmth of
discovery. You never knew what the next hammer blow might
bring, and occasionally there was something astonishing. The
collections were arranged logically, the oldest specimens from the
lowest rock beds exposed were carefully labelled and wrapped
first, then progressively younger collections, and all were shipped
back to the Sedgwick Museum in Cambridge, to which I eventu-
ally returned.

I lived in the Sedgwick Museum for nearly three years, happy
as Larry. At that time research students shared offices in the
attic of the dowdy museum, a nineteenth-century mock-Gothic
building on Downing Street, which still houses the Department
of Earth Sciences. I drove my room-mate John Bursnall mad with
my trilobite obsession. He ran away to the States as soon as he
could, while I continued to learn the messages of the trilobite
shells.

Most of the information about trilobites was buried. The first
task I had to complete was to excavate the specimens ft-om their
rocky matrix, and I spent months doing just this. My original
'lucky break' at St David's was unusual because the trilobite split
out more or less complete: this does not happen often. Usually
you might see the top of the glabella, or maybe an eye; you just
have to grind away the rock that surrounds the animal to excavate
the hidden truth, and that is done later in the warmth of the
laboratory. It is a skilful business, and you acquire the skill at the
expense of heartbreak. Little mechanical percussion needles are
a standard tool - they make an insistent buzzing noise like that
of an enraged wasp - but one slip and you gouge a terrible wound
across the face of the trilobite you've grown attached to. You rely
on the fact that the rock has natural tendency to split around -
rather than across - a fossil. Sometimes you get it wrong and a
lump of your precious find flies across the room, leaving you
grovelling on the floor with a magnifying glass looking for the

32

SHELLS

detached fragment. Some days I would spend hours with a dis-
secting needle peering through a microscope and flicking off
minuscule bits of matrix to reveal the beast beneath. John Bursnall
used to accuse me of carving out fossils to my own design.

The best needles were those used to play the old 78 rpm gramo-
phone records, which were already a rare commodity in the early
1970s. My fellow student Phil Lane and I used to hunt junk shops
for these sharpenable, but hard, steel needles. If we found a cache
we could purchase it for a few pence, to the mystification of the
shopkeeper. 'Can I interest you in some old records to go with
the needles?' he would say. 'No thanks, just the needles,' we
replied, heading speedily for the door and trying not to look as
though we intended to use them for experiments with drugs.

It was soon evident that most of my trilobites were only parts
of the animal. Whole ones like my first lucky find are actually
rather rare. The carapace of the animal often fell to pieces after
it died, like a suit of armour breaking along its joints. Whole
animals do not hang together for long. The tailshield is rather
robust - an isolated pygidium is often the first thing you find
when you split open a piece of rock. The most fugitive part is
the thorax, which disarticulates into its separate segments, which
are then broken or dispersed. The cephalic shield also frequently
breaks into several pieces. A middle part carrying the glabella
makes up one of these fragments. It is called the cranidium. Either
side of the cranidium is flanked by a free cheek, or librigena -
left and right, and mirror images of one another. Many trilobites
carry a prominent spine at the edge of each free cheek which
form spiky hind corners to the head - these are genal spines. The
eye surface is attached to the free cheek in most trilobites: indeed,
the cephalon is designed to split into three or more pieces -
including cheeks and cranidium. The free cheeks are separated
from the cranidium by special planes of weakness - suture lines.
These facial sutures were an aid to the animal during moulting.
The eye surface was probably the most vulnerable part of the
trilobite, and difficult to moult successfully. By splitting the head-

33

trilobite!

shield along sutures which run fore and aft, and include the eye
surface at about mid-length, it was possible to shed the eye surface
before moulting the rest of the carapace. This speeded up the
whole business and reduced the time the animal spent in the 'soft
shell' state. The cheeks were liberated first, and independently
from the rest of the animal, and hence were 'free'. The fixed
cheeks remained behind, next to the glabella on the cranidium.

So the average trilobite yielded a considerable number of bits
and pieces as they fell apart: cheeks, thoracic segments, cranidium,
pygidium. And because they moulted several times as they grew
during their lifetime, casting their old shells and growing new
ones just as crabs and lobsters do today, it is obvious that a large
trilobite would have to shed a succession of its earlier coats as it
gradually reached its mature size. All of those earlier pieces were
potential fossils - trilobites were veritable fossil factories.

But this is where the problems come in. If you only have the
pieces then your first job is to reconstruct the trilobite as it was
in life. It is like having to do a jigsaw puzzle of uncertain design.
Worse still, if you have a dozen or more species of trilobite
jumbled together and all of them fragmentary it becomes more
like doing a dozen jigsaw puzzles simultaneously without having
a colour picture on the cover of the box. While I was learning
my trade, I became adept at matching little pieces. There were
clues. The shape of a suture edge on a free cheek should match
that on the corresponding cranidium. Then my predecessors had
described occasional whole animals in their publications, and
once I had recognized the cephalon, say, as belonging to a particu-
lar type of trilobite I could consult these illustrations for a search
image of the appropriate matching pygidium. Quite soon my
office was a jumble of broken bits of rocks, and needles, and old
monographs, all coated in fine, limy dust. I still work in an
identical office today. Tidy people's eyes go all peculiar when they
come into it. I have a special small padded seat for them to
collapse into.

It was fascinating work, more like that of an archaeologist

34

SHELLS

gluing together potsherds than anything to do with white-coated
science. From time to time Harry Whittington would appear and
make encouraging remarks, or put me right when I had placed
the wrong head and tail together. He was the gentlest of super-
visors, surely better described by the American term the PhD
'advisor'. His advice was always welcome. He had written the
papers and monographs that I most frequently thumbed, and
nowadays my personal copies have lost their covers and become
dog-eared through years of use.

Harry Whittington has probably added more to our detailed
knowledge of trilobites than anyone else. In the 1950s he dis-
covered some remarkably preserved shells. In the Edinburg Lime-
stone, an Ordovician limestone which can be found in a few
roadside exposures in Virginia, the trilobite shells have been
replaced in almost perfect detail by the hard mineral silica. Since
the matrix of the rock is made of limestone it can be rendered
into solution by throwing blocks into dilute hydrochloric acid.
The limestone is often rather dark in colour, and when you place
the piece into the acid it fizzes violently, like an Alka Selzer.
Gradually it settles down to a regular bubbling - more like soda
water. Then you notice that little ridges are starting to project
from the lumps of rock - these morsels are not dissolving. They
are silica trilobites being etched out of the rock. When the process
is complete the fine mud and muck can be washed away through
a sieve, and what remains is pure trilobite.

This is like suddenly having the living shells at your disposal
- handfuls of them. It is as if you have been transported back in
time through more than 400 million years and given the freedom
of an Ordovician beach. You can turn the pieces of trilobite
upside down and look at the underside of the shell for the first
time. You can inspect the doublure. What might take weeks
to prepare manually from the rocky matrix, can be etched out
incomparably well in a matter of days. The larger pieces can be
picked up with fine tweezers, the tiny ones with a moist paint-
brush and transferred to slides. What you discover is a pile of

35

trilobite!

different free cheeks, pygidia, cranidia, and thoracic segments, a
matted palaeontological bonanza. Then they all have to be picked
apart under the microscope and matched together, as one might
sort with excited anticipation through a spectacular box of bric-a-
brac picked up at a jumble sale.

What Harry Whittington's preparations revealed was the fan-
tastical sculpture of some of these trilobites. Spines and prickles
- indeed, prickles on top of other prickles - were all picked out
perfectly by the silica replication. Even the most careful preparator
could never do justice to this thorny magnificence. Some of these
trilobites were hairier with spines than any hedgehog. They
covered the head, sprouted off every thoracic segment - often
splaying off the edge like a defensive comb of slender rapiers -
and continued on to the pygidium, where one pair might continue
backwards beyond the rest of the animal and sprout subsidiary
protuberances. Surely these were animals as idiosyncratic as any
seahorse or spider crab? Even more remarkable was the preser-
vation of diminutive organs on the surface of the animals. It was
possible to see that the tips of many of the spines carried tiny
perforations. In life, maybe, even tinier sensory hairs emerged
from the minute holes, sensitive monitors of their ancient marine
world, quivering to the scents and vibrations of the time.

Other trilobites had a surface covered with ridges as complex
as a fingerprint, swirling in concentric arcs, exuberant as a Jackson
Pollock painting. Others again were covered in tubercles, little
round lumps that made the surface of the shells look as if dusted
with dewdrops. Then there were those that instead of having any
projections had the surface of the shell dotted with tiny pits. One
trilobite we shall learn more about was surrounded by a kind of
perforated sled forming a fringe around the whole of the
cephalon. All these were identified and pieced together by Harry
Whittington when he sluiced out his acid vats, washing away the
millions of years of entombment from the shells as he poured
away the Ordovician muds that had once buried them.

There are some other shelly pieces left behind on the sieve that

36

SHELLS

Amazing spines recovered from the perfectly silicified (see p. 35) trilobites from
the Ordovician of Virginia, USA. This is a cranidium (a), pygidium (b) and
free cheek (c) of a trilobite related to Odontopleura called Apianurus. Even
some of the spines have spines! Such minute details are almost impossible to
excavate manually. (Courtesy H. B. Whittington).

37

trilobite!

did not fit into the now familiar inventory of head, thorax or
pygidium. Most noticeable are a variety of oval plates surrounded
by rims, usually with a pair of long projections at one end. It is
known from the study of complete trilobites that this plate fitted
on the underside of the animal in the middle of the cephalic
shield. The plate was a backwards continuation of the marginal
undershelf - the doublure - at the edge of the trilobite skeleton.
It is called the hypostome. It corresponds quite closely with the
front part of the glabella - but lay on the bottom rather than the
top of the animal. Whatever was within the glabella was accord-
ingly well protected by a calcite skeleton above and below: it
must have been something important to the animal. In fact, this
vulnerable region included the brain, such as it was, and the
stomach - together, the two most vital of the vital organs.

All these shelly pieces of the trilobites were part of what is
called an exoskeleton, because they lay outside the soft anatomy
of the animal. They were the crisp wrapping of a succulent parcel,
lust the opposite is true of Homo sapiens and his vertebrate rela-
tives, in which the flesh is hung on the bones - the soft parts on
the outside. Man is designed so that he can be stabbed in the back.
Trilobites and other arthropods purchased their invulnerability to
treachery at the price of having to change exoskeletons with
growth, shedding every last tiny spine and tubercle and growing
them all over again in a new suit of calcitic clothes. The hypostome
was shed at the same time as the rest of the shelly paraphernalia.

Like the silica trilobites he studied, Harry Whittington himself
has defied the passage of time. As others fade, he carries on
indefatigably studying his beloved fossils. I like to think that this
is a reflection of his own virtues, the unfading ones of kindness
and perseverance. His hair and moustache are still hardly tinged
with grey and he is 83 years old. He is a native of Birmingham,
in the middle of England, but spent many years at Harvard Uni-
versity, which has left him with an indefinable accent - not exactly
transatlantic, but unplaceable. At the time he became my mentor
he had returned from the United States to become Woodwardian

38

SHELLS

Professor of Geology in the University of Cambridge - one of
those ringing titles which are so characteristic of ancient seats of
learning. A pohshed label announced this distinction on the door
of the old office that had been occupied by Woodwardian Pro-
fessors for more than a century. It could have been fusty, but I
always felt that the place constituted a link with previous genera-
tions of scholars, and thence back through uncountable ages to
the time of the trilobites. Somehow one would not have been
very surprised to have been greeted there by the ghost of the Revd
Adam Sedgwick, the nineteenth-century Cambridge geologist who
coined the term Cambrian - the strata from which my very first
trilobite had been wrested.

Harry Whittington often went on fieldwork with his wife,
Dorothy. She was as ebullient as he was quiet, and exemplified
a remarkable principle of discovery: partners always find the best
specimens. Whittington and his students would be squatting in
the floor of a quarry bashing at some grey, tough limestones with
their geological hammers. Thumbs would have been struck, oaths
uttered. From time to time a tantalizing fragment would be found,
sufficient to keep everyone beating the bedrock in a frenzy of
curiosity. Dorothy in the meantime would pick at the odd piece
of strata in a leisurely fashion, all the while enjoying the spring
sunshine. Then would come the question: 'Harry, is this any-
thing?' Sitting in the palm of her hand would be the gem of the
day.

Harry Whittington is an authority on trilobites. There is a
great difference between authority and authoritarianism. Some
professors qualify under both headings, but the best are those
whose authority is earned through the regard of their fellows:
primus inter pares. I have met some of the other variety, too.
When I was a visitor at the University of Gottingen in Germany I
went to the coffee room at the usual time in search of refreshment.
Seeing a spare chair at the table I sat down upon it and started
sipping my coffee. A terrible hush fell upon the room. It seemed
to have something to do with me. Puzzled, I checked my fly, and

39

trilobite!

looked for other signs of disgrace. The wooden chair I sat in
seemed to be identical to a dozen others around the table. After
a minute of excruciating embarrassment, one of the younger men
in the Department came over and whispered in my ear: 'That is
Herr Doctor Professor *****' s Chair!' Mein Gottl I leaped to my
feet, blushing red from my collar upwards, and quickly found
myself another, apparently similar chair. That is authoritarian.

I returned to the island of Spitsbergen in 1972. The trilobite
finds on which I had worked had proved so exciting that the
Norwegian government was prepared to finance a full-scale
expedition to the far northern part of the island to collect still
more, and to fill in the gaps that had been left unexplored. This
was a grand affair compared with my earlier visit, when there
had been just the two of us, plus a tent, a small boat, and as
much porridge as we could eat. The remote shore looked every
bit as bleak on my return, an endless stretch of shingle swept by
an uncompromising wind. I recognized the melt stream which
ran off the great glacier occupying the middle of this part of the
island. We had camped by it before. Arctic terns shrieked a neur-
otic welcome. Now we had a team of eight or so, and a rather
grand tent, almost a marquee, for communal evenings and sitting
out the blizzards. It could be heated up to a delightful cosiness.
Flitches of ham hung from the roof, alongside intriguing salamis.
There was a sophisticated radio system and another kind of ham
to operate it. We could sit at a trestle table in the evening and
exchange the sort of banter that keeps an expedition on its toes.
Once in a while tempers would fray. I concentrated hard on being
everyone's friend.

We had another kindly professor with us - Gunnar Hen-
ningsmoen, from Oslo - possibly the only rival to Whittington
in his generosity of spirit. He presided over our suppers with
unfailing good humour. I shared my little tent with David Bruton,
the only other Englishman, who had long since taken up residence
in Norway, and who spoke Norwegian with gusto to everyone
else. For reasons of outmoded chauvinism the two of us insisted

40

SHELLS

on flying a Union Jack outside our tent, which then slowly unwove
and unpeeled itself over the next few weeks until it was the merest
tatter: so much for the British presence. The oddest experience
for a foreigner like myself was not being able to share a joke
around the dinner table - for jokes do not translate, and anyway
they are born of the moment, and flag with repetition. You sit
there with a weak smile on your lips hoping to demonstrate a
sense of humour even if you have no idea what everyone else is
laughing at. (You hope it is not a joke about you, but you would
sit there with the same silly grin even if it were.) Little bits of
Norwegian came to me by a kind of aural osmosis. The most
surprising linguistic fact I learned was the impoverishment of
that language in swear words. In fact, there /5 only one - Jam
- which merely means something like 'devil take it!', but is con-
sidered very rude by a well brought-up Viking. It has to pass
muster for most of the everyday tragedies that beset an expedition.
If a finger is hammered, you jump up and down and cry 'farn';
if you drop an outstanding fossil irretrievably into the sea, you
splutter for a while and then mutter 'farn' under your breath. If
all your provisions were carried away by a hurricane and death
were guaranteed, all the poor Norwegian could do would be to
stand on the shingle and cry 'farn' into the wind. Somehow this
does not seem adequate for the occasion.

We collected box after box of specimens. Sooner or later they
would find themselves the subject of scrutiny under my binocular
microscope back home. My small personal fragment of history -
ten million years or so - was that distant time when the rocks
enclosing my trilobites had been laid down. I could wander
around that time in my mind as comfortably as a historian might
amble among the Tudors and Stuarts. I could match the various
trilobite pieces together more quickly than anyone else: cranidium
with free cheeks, pygidium with cranidium. Once in a while
somebody would find a complete specimen, which was like
suddenly finding the lid of the jigsaw puzzle. It was a way of
testing your own earlier inferences about what fitted with what.

41

trilobite!

I discovered an extraordinary, goggle-eyed trilobite that I called
Opipeuter inconnivus - which means 'one who gazes without
sleeping'. It could have been a description of me. Slowly, a picture
of a vanished Ordovician ocean was forming in my mind. Why,
there were probably many more species then on the site of my
bleak shore than were able to live there today! The Ordovician
sea was a rich one: just because it was ancient did not imply that
it was impoverished. At that time there was virtually no life on
land, but the sea thronged with jellyfish and trilobites, clams and
snails and segmented worms. There were fierce predators related
to the living pearly Nautilus. There were groves of seaweeds.
There were even shoals of small, lithe animals that might, at first
glance, be mistaken for silvered masses of fish. A palaeontologist
does not only listen to the message of this fossil animal or that.
What he does is to recreate a vanished world.

I was invited to give a lecture on the glories of the new Spits-
bergen discoveries to the Norwegian Academy of Sciences, as
august a body as you could wish for. Norway has special sover-
eignty in this part of the Arctic, so my invitation was not untinged
with politics. It was an intimidating experience to stand before
an audience of a hundred or more of the most distinguished
scientists in Norway, a sea of sages. To be twenty-five years old
and on stage in a fine and historic building in Oslo is not such
an easy occasion to mark the transition ft^om taught to teacher.
The great Arctic explorers Nansen and Amundsen had stood on
that same stage, and portraits of other notables looked on. It was
just as well that there was so much to talk about: the surprise
discovery of some of the richest fossil faunas in the world on the
remote shore of Hinlopen Strait; why others might have missed
the rocks before; how the trilobites proved a connection of Spits-
bergen with the ancient continent of Laurentia; how the climate
at Ordovician time had been tropical rather than Arctic. This was
my first public conjuring of the excitement of deep prehistory.
Once the adrenalin started to course through my system, the
audience became reduced to a hundred sets of ears.

42

SHELLS

At the end a tall and courteous old man stood up and asked
a question in impeccable English. He referred to his time on
Novaya Zemlya in the early decades of the twentieth century. His
name, he explained, was Olaf Holtedahl. I was astonished. It
would scarcely have been more amazing if Fridtjof Nansen himself
had stood up and asked me about my Arctic experiences. Holted-
ahl was a survivor from the heroic generation when Arctic explo-
ration had been truly a trip into the unknown, a time when
huskies were the main means of transport, and pemmican the
main source of protein. In the twenties, he had written pioneering
reports of the geology of the high Arctic, and particularly concern-
ing the remote island of Novaya Zemlya, which points northwards
into the Arctic ocean from the Russian coast like a crooked finger.
Not much had been published about this island since his pion-
eering visits there - and what there was was in Russian, because
it was a highly secret military area during the Cold War. So here
was a figure of romance and scientific derring-do who had stepped
off the page, from the realm of my imagination, and into the
flesh, dressed in a rather immaculate suit.

This incident made me understand a connection with a past
different from that remote one reached by listening to the mes-
sages of the shells: the past of my scientific forebears. In the
egotism of investigation there is a tendency to forget that there
were students before us who made the discoveries on which our
interpretations still depend. Science is an odd venture, at the
same time co-operative and competitive. The motive force is often
the desire to beat a rival investigator to the credit for a discovery.
But in the long term such human rivalries recede, and what
started as a race seems more closely to resemble a series of logical
advances linked together by a roster of names of discoverers.

The first name on the trilobite list is exactly 300 years old as
I write: Dr Lhwyd, whose letter to Martin Lister concerning 'the
sceleton of some Flat-Fish' opened this chapter. The letter was
published in 1699 in the Philosophical Transactions of the Royal
Society, the oldest scientific journal in the English language; the

43

trilobite!

title of the article: 'Concerning some regularly figured stones
lately found, and observations of ancient languages'. I like to
think of these misplaced 'flatfish' rubbing shoulders in the
same journal with the reports of the pioneer microscopist van
Leeuwenhoek listing the discovery of red blood corpuscles, and
microbes, and other such momentous stuff. Trilobites were
smuggled in as observers of mighty things from the very first.
The early volumes of the Transactions are treated with some
reverence, as they should be; the best leather bindings are no
more than they deserve.

Those who know the rocks in the vicinity of Llandeilo are in
no doubt as to the identity of the 'flatfish' - it is a trilobite called
Ogygiocarella debuchii (see opposite). In many places around the
castle - Dynefor Park, just outside Llandeilo, there are pits where
masses of flat-lying, limy flags are exposed; they can be pulled
from the hedge banks in slabs like so many polygonal plates, and
on some of these plates flatfish are indeed served up: the size of
small plaice, and nearly as flat, they have two eyes goggling up
at the surprised collector. The modern observer can perceive that
they have a thorax with eight segments and a large pygidium,
too, and therefore that they are no manner of fish - but you can
see how Dr Lhwyd made his mistake. He embellished the drawing
a little to show something resembling a marginal fin. He was
right only about the eyes.

Trilobites were recognized as a distinct group of animals in
1771 by a German zoologist called Walch, in a work of such
obscurity that I am still not sure whether we have discovered the
right edition in any British library. But within ten years articles
by such scholars as M. T. Brunnich were using 'trilobite' on the
title page, so it must have achieved wide currency - and it is,
after all, a euphonious and descriptive name. More and more of
these distinctive 'organic remains' had evidently been discovered
across Europe. By the first two decades of the nineteenth century
many more trilobites were receiving scientific names, especially
in Scandinavia, France, and Germany. Lhwyd's animal attained its

44

SHELLS

The 'flatfish' figured in the Philosophical Transactions of the Royal
Society by Dr Lhwyd (1679) - in fact, the trilobite Ogygiocarella
debuchii from the Llandeilo (Ordovician) rocks of South Wales. The
trilobite itself is photographed at fig. 1.

appropriate recognition in 1822 when the French palaeontologist
Alexandre Brongniart published a short treatise on our animals,
Les Trilobites, in which he named the species debuchii from a
specimen from Lord Dynefor's estate. The flatfish had finally
vanished, and in its place was a strange animal with a calcareous
skin and segments like a lobster.

One hundred and forty years after the note in the Philosophical

45

TRILOBITE

Transactions Lhwyd's 'flatfish' would be used to recognize and
correlate rocks all the way between Llandeilo and Shropshire. In
Sir Roderick Murchison's book The Silurian System (1839) trilo-
bites like Ogygiocarella debuchii are illustrated not only for their
interest, but also for their utility in identifying rocks of a particular
age. By then the name 'trilobite' had achieved a certain familiarity
among the educated classes which it would never lose again. The
classical names which guaranteed their identity as animals were
given when all scholars knew the Aeneid, and were as familiar
with mythology as we might be with the cast of Eastenders. Ogygi-
ocarella was named for Ogygia, the seventh daughter of Amphion
and Niobe. And in turn both of these names from Greek myth-
ology were attached to other trilobites. It is actually quite difficult
to find a classical name that has not been used for one animal
or another, be it an ever-so-obscure Phrygian nymph or a goat-
herd from the flanks of Mount Olympus. There are layers of time
and levels of antiquity: there is a primal layer, the original ancient
time of the trilobites; then there is the Greek or Latin source of
the names - the time of the 'ancients'; then there is a history of
research; and finally there is a personal history which animates
all those earlier times in the shape of the specimen to hand.

It was not long before similarities between trilobites and living
animals were noted. Segmented creatures were among the fauna
that could be found crawling around on seashores or forest floors
- indeed, they were among the commonest of animals. Insects,
crustaceans, spiders, centipedes - all were constructed from linked
segments which articulated with one another. They shared
another common feature: jointed legs. At first glance, it may be
difficult to appreciate the similarities between the legs of a fly
and the legs of a lobster. But they are jointed in a similar fashion
so that each joint can rotate or swivel relative to its neighbours
in a programmed way according to exactly how they are hinged.
They have the slightly infuriating predictability of one of those
jointed reading lamps: you soon discover that they will swivel in
a finite number of ways, but nonetheless it is possible to direct

46

SHELLS

them into the most improbable corners once you have mastered
the joints. You can get the measure of the range of possible
movements if you hold a struggling lobster upside down - the
legs kick in and out in a mechanical way. Watch a beetle kicking
its legs when stranded on its back and the similarity is evident.
The meat in these animals is all inside the leg; muscles contract
to effect movements along joints. They pull themselves up by
their own internal bootstraps. Jointed-legged animals are called
arthropods, and there is no doubt at all that trilobites were
another kind of arthropod (even though it was a long time before
their legs were found fossilized); had they survived they would
have been lined up alongside scorpions and crabs, butterflies,
beetles and bedbugs as another example of the most diverse and
varied of all animal designs. Carl von Linne (or Linnaeus), the
father of biological classification, had recognized the trilobite
pedigree even before the close of the eighteenth century. Had
they not died out, I imagine that on the beach mothers would
plead with their children: 'Jimmy, please don't pull the legs off
that poor trilobite!' Jimmy would not have been able to resist
the temptation to wiggle the limbs of his captive beast to see how
they could be bent preferentially in certain directions. He would
wave the creepy-crawly trilobite about to scare Aunt Margery,
who cannot stand that kind of thing.

But the trilobite shells I studied in Spitsbergen were only empty
carapaces. Lacking a calcareous coating, the limbs had vanished
into oblivion. I could almost feel the tickle of legs crawling over
my palm, I could imagine the living animal scuttling through the
Ordovician seas. In my mind's eye I could cross-breed the trilobite
with a prawn or a scorpion according to my fancy. But there are
places - rare places - where such speculations can be fleshed out
with real specimens, where even the most delicate and fragile hairs
on the most spindly of appendages are miraculously preserved. It
is to these places we must go if we wish to discover the whole
truth about trilobites, and allow them to tell the tales they have
to tell.

47

Ill

Legs

If you wish to snare a rare butterfly it is no use using a blunderbuss
and a suitcase. To search for something elusive, subtlety and
intelligence is required - and no small measure of luck. Most
quests for unusual goals are motivated by the conviction that the
end is attainable if only the correct combination of fortune
and persistence can be struck. So it was with the case of the trilo-
bite legs.

By the middle years of the nineteenth century several hundred
different trilobites had been named and described. These were
heroic years for monographs. Geologists were mapping and
exploring ancient rocks in a systematic way for the first time.
They were beginning to understand geological time, and creating
names for its divisions, many of which we still use today. As they
mapped the strata in succession they recognized the utility of
fossils in discriminating strata of a particular age. The sequence
of fossil species was a thoroughly pragmatical way of unscram-
bUng the chaos of the strata. In Britain, the explorers of trilobite-
bearing strata were tramping on foot or progressing in carriages
across Wales; they were true pioneers, the first to crack open
ungrateful shales. In North Wales the Revd Adam Sedgwick - in
whose eponymous museum I studied in Cambridge - named the
Cambrian System (Cambria - Roman name for Wales) for ancient
rocks that underlay all the other fossil-bearing strata - the most

48

LEGS

fundamental package of geological time. The name Cambrian
eventually replaced a rival name, 'Primordial', which hinted at
the fundamental position of the organic remains these strata con-
tained in relation to the subsequent history of Hfe. While Sedgwick
explored North Wales, Sir Roderick Murchison was crossing
South Wales, mapping and classifying his Silurian System (1839)
(SUures - a tribe that once inhabited South Wales). Even more
than Sedgwick, he used the fossils to spell out the narrative of
geological time. Trilobites were easy to recognize; they became
the familiar face of various parts of the Silurian. It is easy to
imagine Sir Roderick imperiously summoning the rock-hunting
vicar of some distant Welsh parish to present his discoveries from
his local stream or cwm - and a smile playing on the aristocratic
lips as he identified Trinudeus fimbriatus, or some other old
trilobitic friend. Just as a numismatist might intimately know a
seemingly freshly-minted coin of Hadrian, so the palaeontologist
would greet the familiar face of a species first encountered fifty
miles away and a decade before. Geological time was written in
a thousand trilobites.

The palaeontologists Henry Hicks and John Salter were the
first to tread those cliffs that I visited as a schoolboy in Pem-
brokeshire. I have a photograph of them in the 1870s grinning in
comradely satisfaction at their latest discoveries. The trilobites
they found still bear the imprimatur of their names. When we
cite the Latin name of a species we are obliged to add the name
of the scientist who first gave it its official name. Ampyx salteri
Hicks was an interesting species from the dark slates exposed in
the cHffs north of St David's, first described in a publication of
the Geological Society of London in 1873. Here Henry Hicks
presented a gift to his friend - he named a trilobite species for
him: Salter's Ampyx. Salter reciprocated by naming one of the
beautiful Cambrian trilobites ft-om the Pembrokeshire coast Para-
doxides hicksi Salter. I have done it myself: to celebrate the
devotion of Frank Cross to collecting trilobites in Welsh ditches
in all weathers on behalf of myself and my friend Bob Owens

49

trilobite!

A fantasy trilobite from J. S. Schroeter (1774) - the first portrayal of legs. This
animal combines one head (right way round), one head (reversed) and a tail
(possibly upside down) with purely speculative legs.

there is a delightful small species called Shumardia crossi Fortey &
Owens. Our debt to Mr Cross will thus be recorded in perpetuity.

Wales was only one area which was the subject of intense
palaeontological scrutiny in the period 1830-75. James Hall was
using every means, fair and sometimes foul, to secure publication
of his great monographs on the Palaeontology of the State of
New York; and in Bohemia Joachim Barrande was calibrating the
same time interval with different fossils. But as first dozens and
then hundreds of different trilobites were discovered, and the
bounteous variety of their form became apparent, so too did the
great gap in knowledge of the animal itself. All the fossils were
shells, husks, mute carcases that could not speak fully of their
vanished lives. There was no trace of the jointed limbs that every
observer felt should have propelled the animals along the sea
bed. Some early investigators simply made them up (see above).
Without their limbs these wonderful fossils were geological
cyphers, patterned stones that spoke only of geological time, as
passive in their way as that coin of Hadrian - no more than a
token of real life. Until their legs were discovered it was impossible
really to know the trilobite.

There had to be a way to discover the identity of trilobite limbs
- but how? Their covering must have been the same thin sheath
of the organic polymer chitin, which covers the legs of shrimps

50

LEGS

and centipedes today. This does not fossilize as readily as mineral
shell does, but it is not impossibly evanescent, like the glutinous
shadow of an amoeba, say. There must be circumstances that
might favour the early entombment of these limbs in a sediment
soft or special enough to favour the preservation even of a wisp,
a shadow.

There were hints. Many species of trilobites were capable of
rolling up tight into a ball (see fig. 16). This is a method of
protection in dozens of living animals - even humans instinctively
curl up under a hail of blows. The hedgehog protects its vulnerable
belly this way, and thereby renders itself pathetically liable to be
crushed under wheels for which evolution had never prepared it.
The best comparison of all is with many species of little isopod
- crustaceans that swarm under rotten wood. Almost any old
woodpile will yield them in their hordes: turn over a rotten log,
and their miniature armoured capsules will crawl rapidly away
ft-om the light. They are called woodlice, slaters, or pillbugs
according to where you come from. Like trilobites they have a
shell on their backs and vulnerable legs. Many of them adopt the
same protective strategy - they roll up. I have seen some woodlice
so tight and perfect that they resemble ball bearings - they even
have a sort of sheen. Their segments are perfectly designed to
slide past one another in enrolment. Their legs are adapted to
tuck up inside, like stowing oars inside a boat. Although not
closely related to trilobites (other than being fellow arthropods)
they offer a useful comparison. Many trilobites are equally tightly
enroled - but bigger. You can hold a roUed-up Symphysurus (see
p. 180) in your hand like an egg: it has the same satisfying feel
to it. Look closely, and you can see how the edges of the thoracic
segments have telescoped together, the tips sliding past one
another like the blades of a Japanese fan. The thoracic segments
have special facets to permit this. At the same time the axis of
the thorax has extended, and here an extra 'half-ring' is revealed
between the segments to cover the gap that otherwise would open
up. You can see a similar arrangement on the flexible elbows of

51

TRILOBITE

a suit of armour. Clearly these animals took their enrolment as
seriously as a jousting knight took his protection from sneaky
blows. Some trilobites even had little locks to make sure that the
fit was extraordinarily tight.

Inside one of these enroled carapaces is it not possible that the
stowed limbs would be preserved? This could be the true time
capsule. What was needed was a specimen killed even as it enroled,
and then preserved in sediment quickly - maybe beneath an ash
fall akin to that which buried the unfortunate inhabitants of
Pompeii and Herculaneum. Such volcanic eruptions ft-equently
showered into the sea in ancient times, causing mass mortalities.
It would also be important that the rolled-up ball should not
have been distorted or flattened after burial in the strata. It seems
a lot to ask, but well preserved, whole, encapsulated animals are
known from a number of localities - they were recognized long
ago in the Ordovician limestone rocks of Sweden and Estonia,
and the Silurian ones of England. The trilobites were sliced
through and then polished patiently with emery powder. Surely
the traces of those elusive limbs would show up on the polished
section. Sadly, it was not to prove so. The enroled balls were
filled with fine sediment, which must have oozed in after the
animal was buried but too late to save the limbs from obliteration:
the bacteria got to work and left nothing behind. Quite possibly
the bacteria lived in the very sediments that came to occupy the
capsule. Maybe, just maybe, on one or two specimens, a hint of
a leg cross-section marked by a delicate dark circle, a suggestion
of something else . . . but the mystery of the detailed structure
of the delicate limbs remained unsolved.

In 1876 a young palaeontologist called Charles Doolittle Walcott
(1850-1927) made the first progress in solving the riddle. He was
an avid collector of trilobites in the vicinity of Trenton Falls, New
York, and one of the most remarkable self-made men in a century
when self-improvement was a watchword. He came from a farm-
ing family, stolid and god-fearing and with no particular intellec-
tual bent. Without any formal geological degree, he progressed

52

LEGS

to become the Director of the United States Geological Survey
and Secretary of the Smithsonian Institution in Washington DC.
He undoubtedly had the most inappropriate middle name in
biography. For as well as becoming the ultimate Washington
operator, cultivator of politicians and professors alike, and a very
busy administrator, he found time to produce a great series of
publications on trilobites - and many other kinds of fossils
besides. His books fill a library shelf. He named dozens of the
trilobites w^hich calibrated the Cambrian strata of the whole North
American continent. He investigated the succession of rock for-
mations in the Grand Canyon, often under the most punitive
conditions. This was before the trails had been cut that make the
geologically aged depths accessible today - and even now you see
exhausted walkers who have collapsed by the track because they
have ignored all the notices about bringing water with them.
After all, who really believes that wilderness can be only an hour
or two away fi-om the luxury of a Holiday Inn?

Walcott is most widely remembered as the original discoverer
of the celebrated Cambrian Burgess Shale, in British Columbia,
but, even if he had never made this find, his place in the history
of science would have been assured. The modern worker gapes
in wonderment at Walcott's output. 'Well, he did not have to
answer the telephone all the time,' his contemporary counterpart
might grudgingly allow, 'and in those days he could afford to live
near the office in DC There follows a diatribe on the price of
real estate. All true, no doubt, but it does also seem to be true
that a century ago there were more people like Walcott, with an
extraordinary capacity for hard work which transformed talent
into achievement by force of will. One thinks of Sir Walter Scott
grinding out his great pile of novels (and that partly to pay off
his publisher John Murray's debt). Method was no doubt part of
it; I am sure that Walcott always knew where he had placed
that important piece of paper on the previous afternoon. He
sidestepped those diversions that always persuade us to delay
until tomorrow what we have already deferred from the day

53

trilobite!

Charles Doolittle Walcott (centre) in the field.

before yesterday. He even found time to compile a diary on a
regular basis - another activity which is most often the subject
of good intentions rather than consistent practice. I only wish
that the diary entries were more interesting - for the most part
they reveal nothing of the man, but a lot about his appointments
with the influential. He exposes raw emotion only after the tragic
early death of his first wife, Lura, at a time when he was yet to
receive his first professional appointment. As he rose to greatness
the entries became more and more perfunctory. But it was in the
weeks following his bereavement, when he worked incessantly to
keep grief at bay, that he made the discovery of the elusive trilobite
limbs.

Around the town of Trenton Falls there are limestones which
crop out sporadically along road cuttings or in the sides of

54

LEGS

Streams. These are the strata that Walcott knew so well. The
seams have also been exposed in lime quarries and other pits,
which these days are often in danger of being infilled with the
profligate detritus of the consumer society: a hole is often more
valuable than what was once extracted from it. The Ordovician
limestones are exposed in bench-like beds, and in contrast to the
contorted shales of Wales or Cornwall, these strata are usually
horizontal, or nearly so. It is clear that such rocks have not been
mangled by convulsions of the planet such as those that elevated
ancient mountain chains. They record, virtually undisturbed, a
succession of ancient sea-floors, one after another, which the
young Walcott was lucky enough to explore for the first time. In
some cases a single rock bed an inch or so thick was the product
of a storm that culled the life of a vanished afternoon - and
afterwards the community of animals would re-establish itself by
the time of the deposition of the next rock layer. Even after more
than a century of collecting, the abundance of fossil shells is still
exceptional, and in Walcott's day it must have been astounding.
Often a piece of rock resembles a slab of fruit-cake with trilobites
and brachiopods and snails and sea mats, and many more organ-
isms besides, dotted over the surface like so many plums and
raisins and sultanas. You want to pluck them out, but they are
firmly lodged in the surface, and dusted with a paler limestone
which may obscure their finer details. Patient cleaning with a pin
will clean out the most magnificent examples. Charles Doolittle
Walcott could have first pick.

On 1 March 1876, just over a month after Lura died, Walcott
wrote in his diary: 'Cut up several C. ps. had fair success. I think
I shall determine their interior structure.' This was nothing less
than his note that evidence of limbs might be preserved in 'C.
ps.' The abbreviation stands for Ceraurus pleurexanthemus (you
can understand why he might want a shorthand!), a trilobite with
a spiny pygidium and a knobbly glabella, which is one of the
most exciting finds that can be made from the Trenton rocks. It
had been known as a carapace for more than forty years, since

55

trilobite!

J. Green had named it as one of his in A monograph of the
Trilobites of North America in 1832.*

But there was no hint that this species would offer the key to
fleshing out the reality of trilobite limbs, until Walcott sectioned
and polished the 'Ceraurus layer' - a two-inch-thick band of
limestone in which these animals were common. This single rock
bed had many individuals of the same species. At the bottom
and top of the layer were beautiful, entire, but empty individuals
- shells alone - the ornament of many a collector's cabinet,
but no more informative than a thousand other specimens. The
animals seem to have been trapped by an sudden inrush of limy
sediment such as might have followed upon a tempest - a minor
tragedy in the life of a generation of trilobites, but a boon to the
scientist who followed 440 million years later. In the middle of
the layer were animals that were overwhelmed and killed; some
died struggling towards the surface of their sediment tomb. One
can imagine a quiet sea-floor on which trilobites crawled about
in profusion; suddenly the water darkened with a blanket of fine
mud that settled in a choking blanket before some of the animals
could effect an escape. The poor things had no time to roll up
completely, but many of them had started to flex their bodies,
curving towards an enrolment they never achieved at the moment
of suffocation. Perhaps the idea of the enroled time capsule was
half right, after all. The limbs of these animals trapped in mid-
layer did not immediately rot as did those of animals near the
top. Instead, there was time for them to become filled with lime-
charged water. What had once been filled with muscle became
replaced with white calcite. Like the mummification process per-
fected by Pharaonic priests, a preserving ichor flooded the soft
appendages. The mineral calcite filled the limbs so that, even
when the tissue surrounding was eaten away, infilled moulds

* This is a most peculiar book, for it came with a set of coloured models of the
species described, which can still be found in the drawers of some of our oldest
academic institutions. Green hoped that the sale of the sets would make an additional
attractions for the purchaser. Sadly, some of the reconstructions are somewhat
approximate.

56

LEGS

remained as testimony of the soft parts. Walcott had the insight
to recognize that when his poHshed sections revealed tiny white
circles which contrasted with the surrounding grey limestone,
these were the infilling of the arcane appendages. Within a few
days he had repeated his observations on another species. 'Found
that Calymene senaria has the same character of appendages that
C. p. has. Wrote description of C. p. after supper', he recorded
in his laconic diary entry on lo March 1876. One can imagine
that he would have reported almost any discovery in like fashion:
'Found Holy Grail this a.m.; have expectations of Excalibur
tomorrow.' Trilobites were never the same again.

Consider what Walcott still had to do. The discovery required
him to grind - by hand - a whole series of cross-sections. He
needed to assess how many limbs there were, and whether they
branched or were simple, jointed legs. Limestone is not soft (tap
your nearest Victorian fire surround to prove the point), and he
used a cutting wire and a rotating lap to cut and polish his
sections - a slow business. And, most difficult of all, he needed
to match drawings of sections one to another to obtain a three-
dimensional picture, something that in modern laboratories even
computers find challenging. One can imagine him assuaging his
grief by working on late into the night, curiosity and ambition
displacing other, darker thoughts. Nonetheless he managed to
write his report of his discoveries, which was published in prelimi-
nary form before the year was out. It carried the ponderous title
'Preliminary notice of the discovery of the remains of the natatory
and branchial appendages of trilobites'. While true to the letter
of the discovery, it could scarcely be a best-seller with that title.
In any case Walcott continued to make new observations on
further sections cut over the next eighteen months, and modified
his original reconstruction. But the first version shows several
interesting features. Walcott had noticed one important fact that
still remains true. There were paired appendages on each segment,
and so far as he could judge they were rather similar along the
length of the animal. The appendages hung down below the body

57

Charles Doolittle Walcott's first,
and inaccurate attempt at por-
traying the Hmbs of trilobites
Ceraurus discovered from sec-
tions ground through rock sur-
faces. Right, a modern
reconstruction of the branched
Hmb of Triarthnis (after H. B.
Whittington and J. Almond).

cavity, where the 'guts' were. This visceral mass was largely under
the axis of the animal - the middle lobe of the 'tri-lobes'. So the
legs and other appendages operated underneath the body of the
animal, safely enclosed by the sloping parts of the pleural areas.
Towards the middle were jointed legs - the kind that are typical
of all arthropods, from beetles to tarantulas, scorpions to centi-
pedes. The biological affinities of the trilobite were placed beyond
dispute at a stroke. These were the 'natatory appendages' - Wal-
cott evidently favoured their function as swimming limbs. Outside
these legs were some other branches, three in Walcott's original
reconstruction, one of which branched off the inside of the leg.
The outer ones arose from a common base and were very slender,

58

LEGS

with an odd, corkscrew structure. These were the 'branchial'
appendages - gills for breathing, absorbing oxygen from sea water,
as all arthropods must do. All in all, it was a most plausible
arrangement.

Walcott had been influenced in his reconstruction by using
the limbs of living crustaceans as a model. He admitted as much
to his diary. 'The more I study & compare with the recent Crusta-
cea, the more clearly can I see the true relations of the more
fragmentary parts' (12 July 1877). Though scientists offer a con-
vincing pretence of independent observation, even the best of
them are inevitably carried forward by preconceptions - they
have plausible scenarios lodged in the back of their minds, and
such provisional versions of the truth are based upon previous
reading and experience. Walcott carried with him the notion of
trilobites as related to crustaceans, an idea that was 'in the air' -
recall Thomas Hardy's description, 'one of the primitive Crustacea
called trilobites': that was published in 1873. Walcott's provisional
facts'^ and Hardy's fictional use of the same presumptions con-
verged in the same decade on opposite sides of the Atlantic. Who
knows if these utterly different intelligences had once fingered
the same textbooks?

Trilobite limbs were to leap clearly into three dimensions
thanks to another discovery in New York State. The relevant
specimens were from rocks which looked very different from the
limestones that Walcott studied. They were dark shales, as black
as the formal hats that gentlemen wore for their visits in polite
society. Cleaved with a hammer they could be split into thin
sheets. The Utica Shale was exposed in a quarry in the vicinity
of the town of Rome (this part of New York State was, and still
is, a veritable classical gazetteer). Specimens of a trilobite called
Triarthrus a centimetre or so long abounded on certain levels
within the Utica Shale. A fossiliferous slab could look as if so
many large woodlice had crawled into the rock and died there.

* Before ten years had passed Walcott had favoured an alternative view that trilo-
bites were related to the horseshoe crab, Limulus.

59

trilobite!

On one such piece a graduate student, W. D. Matthew, noticed
something projecting from the front of the cephalon of the trilo-
bite; it was Hke two threads of gold, gently curved. Under a hand
lens the delicate threads tapered, and were divided into segments.
They were antennae! These were appendages that Walcott had
not recognized in his sections. Antennae are the advance guard
of the arthropod body: nose and fingers combined, they appre-
hend their environment with exquisite sensitivity. The description
'feelers' that we used as children hardly does them justice. Trilo-
bites had eyes to see, and antennae to smell and touch; already,
they begin to seem less 'primitive'.

Professor Beecher of Columbia College was quick to appreciate
the importance of the find. The source of the magical trilobites
became known as 'Beecher's trilobite bed', and by the end of the
same year, 1893, he had recorded the new information in print.
He then found the rest of the limbs on the underside of Triarthrus,
but rather than obscure sections, here were whole legs laid out,
outlined in gold. What had originally attracted attention to the
antennae was a gilded film that had replaced the original delicate
cuticle of the trilobite: not gold itself, but fool's gold, iron pyrites.
What a miracle of preservation - as if a preternaturally delicate
hand had sprayed a shiny preservative over the most evanescent
portions of the anatomy, down to the last fine spine. Some speci-
mens preserved on their backs look pinned down almost as if for
a biologist's inspection. These were the specimens that at last
resolved the ambiguities of trilobite anatomy: the end of a journey
towards comprehension that began with the Edward Lhwyd's
'flatfish'. Now it could be seen that slender legs, composed of
many joints, lay underneath another appendage. There were not
two entirely separate appendages, as in Walcott 's original sketch,
but a far simpler arrangement. An upper appendage was attached
to the jointed leg at or close to its base (the limb was therefore
described as biramous: with two rami, or branches), and com-
prised a fine, feather-like brush of filaments. Every segment along
the length of the animal carried a similar pair of branched append-

60

LEGS

ages. The trilobite underside was thus composed of a series of
repeated units of rather similar design - one per segment, a dozen
or more under the thorax. Even the segments on the pygidium
seemed to have a pair of appendages of Uke form, getting smaller
and smaller tov^ards the rear of the animal. Under the headshield
there were three pairs of similar paired limbs, in front of which
were a pair of antennae - unbranched and curved slightly out-
wards. Professor Beecher made a series of models of Triarthrus
from the underside which set his vision of the anatomical truth
in sculptural form. I have one of these models in front of me: it
is a plaster-of-Paris creation about twice life-size. Such is its
verisimilitude that I have more than once been asked to display
it as 'the real thing'.

It is not the real thing, of course. About every thirty years since
Beecher's original report, other eyes have looked at the Utica
Triarthrus and noticed different things. The latest of these
observers was the meticulous Harry Whittington, who in the early
80s employed a young researcher called John Almond delicately
to excavate the pyritized limbs with an air abrasive - a tool that
blows fine powder on to the surface of the shale. The powder is
harder than the shale but softer than the limb material, which
is therefore revealed without damage (or so the theory goes).
Whittington and Almond were able to see clearly the structure
of the jointed walking limb, as explicit as a lobster limb laid out
on a plate - they even found little bristles at the tip of the 'feet'.
The upper limb, the delicately combed one, was thought to be a
gill, a respiratory organ. It extended almost horizontally under
the pleural lobe; indeed, successive combs may have overlapped
one another. Many arthropods have a pleated 'lung' through
which oxygen dissolved in water can be absorbed over the folded
surface. In their modern fashion, Whittington and Almond con-
firmed Walcott's original interpretation of 'branchial appendages'
more than a hundred years after his first tentative sketches. But
they noticed some new things, too: for example, that the base of
the walking legs - and some of the other joints - were equipped

61

trilobite!

Professor Beecher's reconstruction of
the Ordovician trilobite Triarthrus
from the underside, showing the
branched hmbs and the antennae.
There have been many changes since,
but the basic facts are here. The head
is now known to include three pairs
of appendages (plus antennae).
Right, the ventral surface of
Triarthrus, showing the pyritised
limbs prepared by John Almond
from 'Beecher's Trilobite Bed'.

an - antenna
ey - eye
gl - glabella
g.a. - genal angle
hy - hypostome
f.s. - facial suture
fr.c. - free cheek
fi.c. - fixed cheek
Py ~ pygidium

■ V .,- '; ■

/>>"'-"■ '

-, '

^"

■ -; f

■. -•■

'■■ - Vi. '/ .

^ '^ • ,-'■ '%. ^■~'^^

■ ■/

-#■"' X---

.■.%• ■ .jr.- \ -'• '■

-•*-:aAJ^'-'"

: ..-:;„i%^«^,;?T'--^J^^-

•.r-""j^^*^' ^^r-^—

■ '^'-l^^ ■ •*-■■ .

.^ /■

^'■*^., :2 ::^"9 . ^- -

■=

/'^'-- ... .-■ '' ■ • ■■■■

ii - • ' ^ ■"^',' -^

62

LEGS

with surprisingly stout spines. Triarthrus was an altogether prickl-
ier proposition than Beecher would have had us believe.

There is no final truth in palaeontology. Every new observer
brings something of his or her own: a new technique, a new
intelligence, even new mistakes. The past mutates. The scientist
is on a perpetual journey into a past that can never be fully
known, and there is no end to the quest for knowledge. John
Dryden put it well:

In this wilde Maze their vain Endeavours end:
How can the less the Greater comprehend?
Or finite reason reach Infinity^.

There is always a new thought, or a new observation. Those who
crave the certainty of absolute knowledge had better not embark
on the endeavour, for they vydll be frustrated. Every cherished
truth will be revised by those that follow. Real advances are made,
of course, but how do we know that the end of the path has been
reached? This applies to trilobites as much as to the fundamental
particles of matter. Professor Beecher thought he had seen the
truth of trilobite legs, and sought to preserve that truth in his
models - to fix his authority - but work that followed was to
produce a new truth.

The latest visitor to Beecher's trilobite bed was Derek Briggs.
A hundred years after Beecher there were still new steps to take
along the path of discovery in the same quarry - although it
had to be re-excavated. Derek, like myself a student of Harry
Whittington, had become fascinated by the most obvious but
mysterious aspect of the fossils, the preservation of their limbs
by iron pyrites. He wished to understand why this one bed of
rock produced wonderful specimens, with their golden limbs,
where most rock formations yielded only empty shells. After all,
the first slab I ever cracked open in South Wales was a dark
mud-rock superficially like Beecher's bed - but where were the
legs, and why no antennae? It was clear that the covering of iron
pyrites must have happened very quickly, otherwise the legs would

63

trilobite!

have decayed away. The animals themselves probably died sud-
denly, and were then protected from the activities of scavengers,
which normally pick carcases apart even before the decay bacteria
can get to work. There were clearly special conditions on the
Ordovician sea-floor in New York State at this one moment in
geological time.

Close study of the shales showed that the sea-floor of the time
was very low in oxygen, and beneath the surface of the soft mud
lacked it completely. Such inhospitable environments, termed
anaerobic, are well-known today. They are capable of supporting
very little in the way of animal life, but there are special kinds
of bacteria which revel in them. In the almost complete absence
of oxygen, they have developed special methods to extract energy
from their own biochemical reactions. High concentrations of
iron and sulphur are typical; the bacteria use the sulphur in their
metabolism. It is very likely that it was the activities of millions
of these tiny bacteria that promoted the deposition of iron on
the limbs. Derek is currently trying to understand the process by
devising experiments to reproduce artificially what nature did
millions of years ago. It is proving complicated, but enough is
known to visualize the scene. Poor Triarthrus was overwhelmed
and died, possibly poisoned by a sudden drop in oxygen - nothing
can breathe in its complete absence. No scavengers dared struggle
through the hfeless water. The limp limbs were enfolded in the
soft embrace of the mud, where only bacteria thrived in a soup
rich in iron and sulphur. They painted the surface of the Hmbs
before decay could obliterate them. So preserved in iron pyrites,
casts of the limbs defied time.

Now it is my turn briefly to enter the story. One mystery about
Triarthrus remained unsolved. If this Ordovician sea-floor was
so inimical to life how could it be that so many of these little
trilobites seemed so happy to live there together, at least until
they were killed? Very often they are found almost alone, with
no other trilobite species (or indeed other fossils) alongside them.
Nor was this unique. Triarthrus is only the youngest of a whole

64

LEGS

trilobite family, known as Olenidae, with a history going back
more than 50 mUHon years into the Cambrian strata. I had come
across Olenidae first on the bleak shores of Spitsbergen, where
they abounded in similar, but older, Ordovician black rocks,
which were deposited on a sea-floor where nothing else could
thrive. These rocks were so sulphurous that they stank of rotten
eggs when you broke them under your geological hammer. It was
obvious that these trilobites had some special secret that enabled
them to prosper in a home redolent of brimstone. Triarthrus was
there, but so also were some related - and hitherto undiscovered
- larger trilobites: one of these I christened Cloacaspis, after the
Roman sewer cloaca, for reasons which will by now be obvious.
(The original, constructed by Tarquinius Priscus, conducted the
filth from the streets of Rome into the Tiber.) I was to see similar,
still older rocks around the Norwegian capital, Oslo, where the
Cambrian ancestor of all these trilobites, Olenus itself, abounded.
The smelly nodules which yielded their remains are probably the
only noisome thing in this most orderly and spotless city. Olenus
was one of the earliest known trilobites, named by the pioneer
Scandinavian geologist J. W. Dalman in 1827 after the husband
of Lethaea. Together husband and wife were turned to stone by
the gods - the most appropriate classical names were grabbed by
early palaeontologists! All these olenid trilobites flourished in
sulphurous muds rich in iron, in a habitat in which there was
very little oxygen - conditions which effectively banned all the
competition.

It is only in the last few years that animals adapted to a similar
habitat have been investigated in detail. Nature is adept at making
a virtue of necessity, by turning hardship into opportunity. In
stinking mud today there are types of clams that grow special
bacteria in their gills. The bacteria process sulphides, and the
clams can maintain just enough oxygen to allow the bacteria to
do their work - too much oxygen would actually oxidize the
sulphur compounds that provide the bacteria with their food.
They are thus animals on the edge. They live only in low-oxygen

65

trilobite!

habitats, where below the soft sediment surface there is no oxygen
at all and sulphur compounds abound. The special bacteria are
known as colourless sulphur bacteria, and they require modern
microscopical and molecular techniques for their study. Neither
Beecher nor Walcott could have had a clue as to their existence.
Clams can absorb nutrients from the bacteria directly, but other
creatures that 'cultivate' them use them as food.* When I studied
olenids I, too, had concluded that they lived in a low-oxygen,
marine environment stinking of sulphides. Then I came across
records of the living symbionts that grew their own sulphur bac-
teria, and discovered under what conditions they thrived. It was
a grand moment. Suddenly it was possible to make sense of so
many features of Olenidae. It was now obvious why they lived
in numbers together to the exclusion of other species, and in
company with such unpleasant rocks: this was their speciality.
They had long bodies with large numbers of segments in the
thorax - aU the more space to grow bacteria. They may even have
grown them along the long 'filaments' of the gill branch, like the
living clams. Safe from predators they had very thin shells. There
was iron available to replace the limbs. AU the facts hung together:
these particular trilobites were the first known animals to live
symbiotically with sulphur bacteria.

The Utica Shale was not unique in its exquisite preservation
of trilobite limbs. In Germany, to either side of the River Mosel
and in the adjacent parts of the Rhineland, another dark slate
comes to the surface. The Hunsruck Slate has been used for
roofing since medieval times, and by the middle years of the
nineteenth century there were many productive quarries. Even
today, an open cast working at Bundenbach still employs thirty
slate splitters. In geological age this slate lies between the Utica
Shale and the Carboniferous with which this book began; it is early
Devonian (about 390 million years). The slates were squeezed
as part of the complex Hercynian earth movements, the same

* For those who like polysyllabic descriptions to impress people I should say that
these animals are correctly referred to as chemoautotrophic symbionts.

66

LEGS

convulsion that affected the slates that made wild Pentargon Cliff
on the Cornish coast. At certain levels in the Hunsriick Slate
fossils are replaced by iron pyrites, just as they were at Rome,
New York. But the circumstances differ. In Hunsriick an entire,
rich marine fauna is pyritized: starfish, sea lilies, worms, fish.
Creatures with soft bodies were caught by surprise, as in a snap-
shot. If this book had been about starfish I could have filled pages
with a celebration of the Hunsriick wonders. There was nothing
restricted or peculiar about this Devonian sea-floor: it was burst-
ing with life, and there was presumably plenty of oxygen. Trilo-
bites were just one of many kinds of arthropods that crawled
around on the soft Devonian muds, although they were the most
abundant. It is now thought that the whole sea-floor was over-
whelmed by occasional muddy slurries that were sufficiently
charged with iron to effect the pyritization of the fossils. Professor
Wilhelm Stiirmer perfected a technique of taking x-ray photo-
graphs of these buried animals. Although it is possible carefully
to dig out the fossils, as John Almond did from the Utica Shale,
how much better to peep inside the solid rock to photograph the
buried animal, which William Conrad Rontgen made visible by
his discovery of x-rays in 1895. The iron pyrites is more opaque
to x-rays than the surrounding slate, and the fossils are outhned
on their radiographs as if drawn by a deft artist in a soft, dark
pencil. They have a ghostly quality; one might imagine they had
been called up from the past by incantation rather than by science.
The commonest of the trilobites in the Hunsriick Slate is an
animal some centimetres long called Phacops. I have in front of
me a wonderful x-ray of this animal (fig. 6) in which the append-
ages are shown clearly, but superimposed by the x-rays, as if they
were in a state of fluttering movement, like the walking figures
in the Futurist paintings of Umberto Boccione. They are the
nearest thing we will ever see to a living trilobite, but we see it
through a photographic plate, darkly. Phacops is not closely related
to Triarthrus, and it is surprising to find that their appendages were
in many ways alike: similar antennae, similar paired limbs on every

67

trilobite!

The legs of the Devonian trilobite Phacops preserved in iron pyrites from the
Hunsriick Slate, Germany. (Photograph courtesy Prof W. Haas.)

segment. The x-rays reveal the fine tips of the gill branch better than
a pin ever could. Here is proof that fossils could record something
more delicate than lace, and as fugitive as a cobw^eb.

As more and more trilobites with preserved appendages were
discovered, most of them were found to have limbs of similar
kinds along the length of the animal - and each limb comprised
a paired walking leg and gill branch. Trilobites did not develop
the specialization of individual limbs which happened in many
other kinds of arthropods. Think of the nutcrackers of the lobster,

68

LEGS

or the extensible sucking pad of the fly. Instead, most trilobites
retained a comparatively unspecialized locomotion; it was the
shell that evolved into an array of fantastical shapes. Carnival
floats flaunt colourful and extravagant paraphernalia, and it
comes as a surprise when the dressing is removed - beneath is a
humdrum Ford. We have laid bare the workings of the trilobite:
what lies under the chassis is no longer mysterious. We are ready
to envisage a parade of trilobites walking past on their paired
limbs: and it will be as odd a parade as any carnival could offer.
Some smooth as eggs, others spiky as mines; giants and dwarfs;
goggling popeyed popinjays; blind grovellers; many flat as pan-
cakes, yet others puffy as profiteroles. There are thousands of
species. They are so prolific that they have been dubbed 'the
beetles of the Palaeozoic', and beetles are the most bewilderingly
diverse of living organisms; biologists are left breathless trying to
calculate just how many species there may be. Nor are we any-
where near knowing how many kinds of trilobites still lurk undis-
covered in the rocks. Our trilobite march-past can only be a
selection of a selection. It will cover 300 million years of history
in a page or so. A glance at the illustrations will give a better
idea of the extraordinary variety of form that the trilobites
achieved. The parade will be in approximately geological order,
with the oldest first. How they evolved into such a variety will
be the subject of a subsequent chapter, and the trilobites described
here nearly all appear as characters elsewhere in this book. To
me, all the creatures named are as familiar as kin.

First comes Olenellus, (fig. 10) commonest of the earliest
Cambrian trilobites (535 Ma). It was discovered in the mid-
nineteenth century by the pioneer New York State palaeontologist
James Hall, and has subsequently been found very widely, includ-
ing as far away as Scotland. Although it is so ancient, its large
and long cephalon already carries a pair of extended eyes. The
widest part of the animal is at the head end where there are
prominent spines at either corner, behind which the body tapers
gradually backwards along a thorax comprising many, rather flat

69

TRILOBITE

segments with prominently spiny tips. One of the thoracic seg-
ments, near the front, is much more strongly developed than the
rest, so that the pleural spines project beyond the rest of the
body. Then there is a long spine rising from the middle of the
axis of the thorax, near the back end of the animal, behind which
the segments are very tiny, and the pygidium is really minute.
Somehow this looks like a primitive trilobite. It has not yet
developed the sutures crossing the headshield that helped its rela-
tives during moulting. The tapering glabella is very clearly divided
by furrows into segments, and its front is almost round, like a
boss.

Olenellus is followed by a giant, the size of a large lobster. It
is a rapid mover, striding purposefully in pursuit of smaller fry,
which it can spot with its glistening eyes. This is Paradoxides (see
p. 213), which has already been introduced as having a name to
match its oddities. It was originally discovered in Sweden in the
early nineteenth century; now it is known very widely. It too has
many thoracic segments, but lacks one considerably larger than
the rest. The genal spines are fearsome, extending backwards like
a pair of swords. Pleural spines at the back end of the animal
extend backwards beyond the tail like the kind of drooping mous-
taches sported by the bad guys in westerns. The tail, although a
little larger than that of Olenellus, still does not amount to much.
But the furrowed glabella is swollen - the whole thing expands
forwards, and beneath lies a stomach which must also have been
enlarged, probably to engorge prey. Paradoxides is mid-Cambrian
in age, fifteen million years younger than Olenellus; still early
days, one might say, but Paradoxides clearly meant business.

Now there is a flickering swarm - are these trilobites, too?
They look like tiny animated beans, just a few millimetres long.
This is a fly-past (or swim-past) rather than a parade, for these
little animals are sculling through the water like so many water
fleas. They are so small that you to have to squint hard to see
how different they are from their other Cambrian relatives. Some
of them seem to be rolled up tightly. They are as different from

70

LEGS

Paradoxides as can be imagined, and not only with regard to
size, for these animals have very few, perfectly hinged thoracic
segments - in fact, only two, which are bluntly tipped as if
chopped off with a tiny scalpel. And it is hard to tell head from
tail: both are equally large, and there is no sign of eyes. So these
are little blind trilobites which have turned into something totally
different from the crawling spectator of Mr Knight's clifftop pre-
dicament. They are strange miniatures, specialized, sophisticated,
and so successful that when there was plenty of plankton on
which to feed they must have turned the late Cambrian (505 Ma)
seas dark with their numbers. They are found in every continent
in rocks of the right age. Agnostus is the name for these little
enigmas - and how appropriate! - and the species that is so
common in our parade is called Agnostus pisiformis (fig. 11) -
literally, the 'pea-like unknown one'. The genus name was given
to Agnostus in 1822 by Brongniart, who will be recalled as having
named the 'Flatfish' from Llandeilo as a good trilobite. I have
handled limestones from Sweden which are made of almost noth-
ing but this tiny agnostid trilobite - rocks that can look like
petrified pea-soup, a cobble of knobbles. Curiouser and curiouser.
Here comes another stately animal. It is the size and shape of
a small silver salver, rather convex and smooth, and, like Agnostus,
it has a pygidium as large as the headshield. But there the resem-
blance ends, for this trilobite has eight thoracic segments, each
perfectly faceted so that rolling- up can be effortlessly achieved.
Its eyes are prominent, shaped like crescent moons and elevated
on stalks so that they resemble a pair of up-periscopes perched
atop the head. The glabella is not so clearly marked as in Para-
doxides, neither are its furrows so deep. Nor are there are any
genal spines, so that this trilobite looks polished and rounded off
at the corners, built for smooth ambulation. One of these animals
has partially buried itself in the soft mud, where it can be recog-
nized only by a vague disturbance in the sediment surface, and
by its eyes projecting above it, unblinking in their vigilance. Isot-
elus (fig. 12) is a more convex version of Lhw^d's Ogygiocarella

71

trilobite!

from Llandeilo in South Wales - and indeed it is one of its close
relatives, and of similar Ordovician age (470 Ma).

Isotelus dwarfs some of its contemporaries, one of which is a
little medallion-like creature with a puffy head, and almost flat
thorax with six segments and a perfectly triangular tail. These
trilobites have enormously long genal spines - far longer than
the rest of the body, so that the animal is supported on them
like a sled upon its runners. The glabella is higher than the rest
of the animal, and inflated like a pear; it is hard to see any
evidence of eyes, so this was probably another blind trilobite.
Most extraordinary of all, the head was surrounded by a border
full of perforations, like a colander. The pitted fringe lay at the
front of the head in the manner of a halo - and the pits were
not just scattered willy-nilly. Instead, they were organized clearly
into rows and lines, each species having its own particular
arrangement. Each has the size and perfection of a coin, minted
to a design as precise as a dynastic intaglio. On the underside,
rather feeble little Umbs propelled the little medallion from spot
to spot: these species did not leave the safety of the sea-floor for
long. The name Trinucleus (fig. 13) is too obvious to require any
explanation from a Latin thesaurus; it was donated to these
peculiar animals by Sir Roderick Murchison in 1839 after he had
made his seminal Welsh traverses (1833-7). Modern study has
shown that the fringe around the head is matched closely by a
modified lower layer of shell, a 'lower lamella' on which every
pit is opposed by a corresponding tubercle. The fringe is a compli-
cated piece of natural engineering, a double-up plate punctured
by little tubes. This animal must have been as specialized in its
Ordovician fashion as anything in the modern ocean. But how
it lived remains an enigma: five generations of palaeontologists
have studied these perfect little animals and wondered. Trinucleus
itself is confined to Wales, but its close relatives are found
worldwide.

Now some swimmers scull into view. Here are trilobites that
are extraordinarily gifted with eyes. They bulge prominently, as

72

LEGS

if they suffered some thyroidal condition. Almost the whole of
the side part of the headshield has become a great, inflated visual
surface: the free cheeks have become converted into nothing but
eyes. The honeycomb pattern of the lenses is as clear as in any
dragonfly. Even more bizarrely, the eyes have actually fused
together at the front of the animal, so that effectively there is just
one huge visual organ, or headlamp. This is Cydopyge, discovered
originally by the Bohemian palaeontologist Joachim Barrande in
1845. (A very close relative is shown at fig. 15.) The name is derived
from the Cyclops, mythical one-eyed giants of classical Thrace.
Our trilobites are not giants except in the optical department;
overall, they are the size of large bees. But in the matter of eyes,
what a wonder! The rest of the creature is smoothed out, and
compact. It is hard to see exactly where the glabella is on this
trilobite: it remains as a flat area between the eyes; there are six
strong thoracic segments, each one well-articulated to its neigh-
bours. This animal was built for swimming. The pygidium was
nearly semicircular, and had a short axis. While Trinucleus grovel-
led on the seafloor, Cydopyge cruised above it.

lUaenus is about as convex as trilobites get: the whole animal
resembles an armoured carrier, with all its edges rounded off. Its
eyes were rather small and set high up on a head that sloped
steeply down to its margin. Glabella and thorax merged smoothly
into one another, and the thoracic pleurae hung down steeply.
The tank-like profile continued into a large semicircular tailshield,
which was also nearly smoothed out, so that you have difficulty
guessing how many segments went into it. When lllaenus rolled
up it attained a nearly perfect sphere, unbreachable by any pred-
ator. It was an armadillo among trilobites. (Bumastus, a close
relative, is shown on fig. 3.) It is not hard to imagine a predatory
Ordovician or Silurian contemporary of lllaenus trying in vain
to prise open one of these tight capsules; and all the while the
crystal eyes gazed on to register the frustration of its foe, as the
animal bided its time until it could unroll and scurry off to safety.
As with so many trilobites, lllaenus was first discovered in Sweden

73

trilobite!

in the early nineteenth century, and has since been recognized
on nearly every continent.

Calymene is regarded by many as the typical trilobite. This is
probably for no better reason than that it has appeared in so
many textbooks as the first example for students to learn. It is
one of the commonest trilobites in Silurian strata (about 425 Ma)
and was found in the classical Wenlock district, where are exposed
some of the first British Lower Palaeozoic rocks to be fully investi-
gated. A. E. Housman's Wenlock Edge is a bluff of Wenlock
Limestone, commanding a view westwards to Wales, where heads
of fossil corals weather out slowly under the gentle wash of the
Shropshire rain. In the town of Dudley, Worcestershire, quarries
which were active in the eighteenth and nineteenth centuries
yielded hundreds and hundreds of beautifully preserved examples
of Blumenbach's Calymene {Calymene hlumenhachii). Any collec-
tion worth its salt has one or two of these specimens. They
are singularly satisfying things, palm-sized, plump, emanating an
undeniable, primal charm. One of the objects I have to lock away
in the collections I look after is a marvellous, gold-mounted
Calymene brooch (fig. 17) which once must have made a most
arresting conversation piece when pinned on the bosom of its
former owner. The 'Dudley locust' appears on the coat-of-arms
of that town (and surely those who named it knew an arthropod
when they saw one, even though 'locust' is a little approximate).
The enthusiastic curators of the local museum want to build a
great education centre in the old quarries in the form of a huge
Calymene where visitors can dine under the glabella and learn
history under the thorax. I am all for it. The convex trilobite had
a tapering glabella carrying very deep furrows; free cheeks like
two-thirds of a circle; twelve thoracic segments with a very promi-
nent axis; and a neat downsloping tail smaller than the head,
which tucked underneath the cephalic rim when the animals
enroled. I like to hand round rolled-up Calymenes to school-
children so that they can weigh more than 400 million years
of history in their hands. Such an engagement with the real

74

LEGS

object is worth a dozen videos. A sense of wonder is not to be
bought over the counter at the superstore. Nor is it something
which can be wheeled out of a corner cupboard at the behest
of some curriculum or other; instead, it steals up on the child
unexpectedly.

Radiaspis is a hymn to prickles. It is smaller than Calymene,
but makes up for it by sprouting spines everywhere. All around
the front of the cephalon there is a comb of spines; there are
genal spines; there is not one, but two spines arising from the
tips of each of the flattish thoracic segments; and there are long,
elegant spines arrayed around the pygidium. You have to look
hard to recognize that the stalked eyes are not yet another pair
of spines. Radiaspis is an odontopleurid trilobite, which means
'toothy pleura' and you can see why. The glabella is divided into
curious round lobes; there are further spines on the axis of the
thorax. You instinctively know that this was another specialized
animal, because it evokes that same sense of oddity you experience
when you see a seahorse for the first time, or a long-eared bat.
You feel suddenly in awe of the richness of the natural world.
Odd it may be, but the odontopleurid design (see fig. 32) was
singularly successful, lasting from the Ordovician until the
Devonian (500-370 Ma) and generating hundreds of different
species, each bedecked v^th a different arrangement of the spines.
The related genus Dicranurus is illustrated on the cover of this
book carrying its ramshorn-like spines at the back of the head.

And still they come. We have already met Phacops (fig. 18), a
large Devonian trilobite having special eyes with enormous lenses,
through which we shall see the ancient world with special clarity
in the next chapter. The first Phacops specimens were discovered
in Germany in the 1820s; then they were found in Britain, France
and North America. The carapace is covered with coarse, warty
tubercles. As I write I am running my hand lightly over the surface
of a large Phacops ft-om Morocco. These particular trilobites have
been commonly available on the market since about 1985, and
most are rather roughly dug out from their limestone bed, so

75

trilobite!

that they almost have the look of a sculpture. My own specimen
feels rough, like one of those old-fashioned dill cucumbers; my
fingers feel out its eleven thoracic segments. This trilobite is so
well-defined by ridge and furrow it can be read like Braille. The
glabella expands forwards into a triangle; the pygidium is deeply
segmented. One of the common species is Phacops rana - the
describer must have had the warty 'skin' in mind, rana being the
Latin for a frog. Some specimens from the Silica Shale in Ohio
weather out from the white shale as if moulded in burnished
pewter. They are found in clusters, and at least one observer
thought that they gathered to mate before being overwhelmed by
disaster. If so, a moment of procreation would have become the
moment of preservation.

There are many more trilobites which scuttle past so swiftly
that we can see only one or two salient details before they pass
from view. Here is Crotalocephalus (fig. 19) with a tail like a cat's
claw carrying a few large, curved spines; then Dalmanites with its
single spine extending from the back of the pygidium like a marlin
spike. Now comes Scutellum (fig. 21), flat as a flounder, but with
a huge pygidium shaped like a ribbed fan - one flip and it is past
us. A gigantic Lichas is nearly as flat, but with the glabella blown
up, like so many bubbles, and with a fluted pygidium with a
coarse saw-edge. Nearby, there are some tiny trilobites buried in
the soft mud, probably diminutive blind grubbers called Shumar-
dia (p. 222). There follow more spiny monstrosities - Comura
(fig. 34), with so many vertical spines it looks like a fakir's night-
mare. And so the parade passes on and on.

The very last trilobite is a smallish one, Phillipsia (close relative
Griffithides, fig. 23). This animal is named after lohn Phillips,
whose Illustrations of the Geology of Yorkshire (1836) earned him
the right to be so immortalized in stone. At first glance this new
trilobite does not seem such a remarkable animal compared with
some of the phantasmagoria which have flickered before us. But
it would have been a relative of this species which Thomas Hardy
placed into Beeny Cliff in North Corwall; it was a Carboniferous

76

LEGS

(330 Ma) crawler with large crescentic eyes, and the whole shell
dotted with prominent tubercles as if it were suffering from an
attack of Palaeozoic measles. The tapering glabella seems as badly
infected as all the other body parts. The tailshield is very large,
and deeply furrowed. Maybe Hardy had seen illustrations of this
very animal drawn by Phillips from Yorkshire, and saved the
image in his eclectic mind. There is no particular feature that
marks it out as a survivor, but that is what it was, for several
relatives of Phillipsia were the last trilobites of all. They lasted
into the Permian period (260 Ma) before they and their kind
became extinct. At last, the 300-million-year-long parade has
come to an end.

It should be clear by now how a lifetime can be spent trying
to catch a few moments of this parade. There is so much history
to learn, and only a handful of shells to reveal it to us. For every
animal that clearly comes into sight another dozen escape, or
leave only their footprints in the soft mud. A puzzled fellow
commuter on the train once asked me how I could go to the
office day after day to study a trilobite. I think he believed that
there was only one trilobite, rather like the Mona Lisa, and that
my day was spent contemplating it and making up new theories
about its enigmatic smile. I had to explain that my work was
more like attending to an almost infinite system of galleries hung
with Mona Lisas, and that often all we had was the smile. And
every time the end of one gallery was reached, there was another
gallery beyond still to explore, and further again another . . . and
hardly ever the legs.

There are some curious advantages in belonging to a small
scientific world like the circle of trilobite specialists. You know
almost everybody: it is like an extended family. As in all families
there are feuds and disagreements, but kin loyalty wins out in
the end. As in all families there is an acute awareness of family
history. Charles Doolittle Walcott is regarded as one would a
famous ancestor; we suffer with those that went mad, like poor
John Salter, or died under Nazi persecution, like the tragic Rudolf

77

trilobite!

Kaufrnann. There is a solidarity that transcends generations and
national barriers. It does not matter where you go; if there is a
'trilobite person' there you will find a ft-iendly face at the airport,
and before long you will be swapping the names of fossils like
unofficial passports. When I arrived at Almaty airport in Kazakh-
stan in 1996, in the middle of winter, I stood outside the rather
large shed which passed as the International Terminal. Sleek
limousines pulled up - but they were not for me, they were for
the new post-Soviet generation of businessmen, intent on buying
and selling oU or minerals, or, for all I know, their grandmothers.
As I loitered, now on my own and feeling a little disconsolate,
my breath coiling up into the frosty night air, I spotted in the
distance an ancient Trabant. Stuttering along like a jalopy in a
Pluto cartoon, scattering rusty flakes like dandruff, it wheezed to
a halt beside me. Out of the window leaned the beaming face, gold
teeth flashing, of my Kazakhstan colleague Mikhail Apollonov. 'I
have arrived!' he stated grandly, if unecessarily. Within minutes
we were swapping trilobite intimacies and gossip.

78

IV

Crystal Eyes

It might seem hardly worth questioning the idea that the world
is made for seeing, or that eyes are consequent upon the unde-
niable fact that there is so much to be seen. Yet think for a
moment and the inevitability of vision is much more uncertain.
The world is full of other signals that may be used to describe
it: there are smells, chemical signals both subtle and ubiquitous,
and touch is as sensitive to shape as sight - more so, because it
cannot be misled by trompe Voeil or by camouflage. Imagine a
world in which the eye had never developed - not the eye of
insect, nor of fish, nor of mammal, nor yet Mankind. It is easy
to conceive of the other senses having taken over the comprehen-
sion of their surroundings. It would be a world of palpation, of
feelers, a world in which caresses would have rendered glances
superfluous. The twitching and waving of antennae would accom-
pany every action. It is not difficult to imagine that a different
evolutionary course would have selected those organs most deli-
cately attuned to the passing molecule: even now we know of
moths so sensitive to the pheromones of the opposite sex that
the most evanescent whiff of a mate can stimulate a love flight
across kilometres. In a sightless world, sensitivity to such stimuli
would be selected and refined: it would be a world of nuance so
delicate that our gross maulings would be inconceivable.

In conscious animals this most sensory of environments would

79

trilobite!

entail everywhere the language of touch and smell: beauty would
be aural or tactile or olfactory. Poetry would not celebrate the
unfathomable mysteries of eyes and their unplumbable depths,
nor compare hair with flax, for visual similes would be redundant.
Rather, the texture of skin might be the supreme erotic stimulus,
or natural selection might have favoured an ever more elaborate
array of perfumes and chemical attractants, which in turn would
evolve a language of which we can only dream. There might
be symphonies of perfume, Mozarts of musk. Novelists might
construct nasal narratives, versifiers sonnets of scent. Sculpture
would entail subtleties of shape that only fingers trained through
hundreds of millions of years of tactile evolution could discrimi-
nate. There would be no word for 'blindness'.

So I don't believe that light inevitably engendered sophisticated
sight, simply that that particular path was taken by life on this
planet, elaborating and improving upon the simple photosensitiv-
ity of single-celled organisms. The eyes of the trilobite are tangible
proof of a selection of one special branch of evolution ft-om an
array of possible alternatives - an innovation that made the world
visible. Once passed, this threshold could not be forgotten, even
if some animals - trUobites included - once more lost sight of
the world in favour of fumblings in the dark.

Recent laboratory work has revealed the pervasive influence of
the genes that control the sequence of development of the various
organs as animals grow from embryo to adult. The master control
is the family of HOX genes. It is astonishing to find that similar
genes control the placing of the head in the locust as in the fish
(or kangaroo, or human). These are genes so deeply embedded
in the unconscious mind of our bodies that the memory of their
origin is lost far in the Precambrian history of development of
the earliest animals. We can never, ever, directly sample the gen-
etic code of the trilobite - but we can be sure that its development
was under the control of HOX genes of kinds that we could still
recognize in living animals.

The argument that allows this assertion is entirely a matter

80

1. Probably the first trilobite to be
recorded in a scientific journal, the
Reverend Lhwyd's 'flatfish', now known
as Ogygiocarella debuchii, ft-om the
Ordovician rocks of South Wales, near
the town of Llandeilo. Eight thoracic
segments and a large pygidium, and big
crescentic eyes. Twice natural size.

2. Silicified trilobite headshields, dissolved out
of limestone using acid. Harry Whittington's
preparation of the Ordovician trilobite Cerausus
from the Ordovician of Virginia. USA, x2. This
head-shield from the underside (b) shows the
hypostome in position, and viewed from the
front (c) you can see how it bulges downwards
beneath the glabella to house the vital head
organs of the trilobite.

3. ABOVE LEFT Bumastus, a locm-long
trilobite in which many of the features
have become smoothed out, or effaced.
You can hardly discern the glabella,
though the eyes are quite prominent. ,
The whole animal is very armadillo -

ike. Silurian, Shropshire, UK.

4. LEFT AND BELOW RluHaSpis, a ■

fantastically spiny trilobite from the
Devonian rocks of Morocco. Delicate
spines originating from the thorax
curve back over the spiny pygmidium;
another pair of spines come backwards
from the 'neck' region.

5. ABOVE Dalmanites, one of the first
trilobites to be discovered, and which
abounds in the Silurian rocks of
Europe, often about locm long. A
short spine at the back of the tail is
characteristic. This specimen is from
Shropshire, UK.

» *

:» -f

-*^

r - /f-

/^^

.>4'

^>

^•^

m. ■« i

.|t»^

if

^4^^

i

If

6. ABOVE X-ray of the Devonian trilobite
Phacops from the Hunsriick Shale of
Germany. The legs appear ghost-like and the
fringes of the gill branches show at the edge.

7. RIGHT Olenoicies serratus horn the
Cambrian Burgess Shale. Details of the limbs
taken from Harry Whittington's incompar-
able photographs: the thoracic segments are
on the left; the strongly spinose walking legs
extend to the right. You can see the massively
spiny bases of the legs very well in this
picture

8. RIGHT An olenid trilobite, Hypermecflspfi
approx. life size, showing small headshield
and long thorax with numerous segments.
This specimen is preserved upside down so
that it shows the hypostome (covering the
stomach) more or less in life position.
Ordovician, Bolivia.

9. BELOW A 'graveyard' of the olenid trilobite
(see p. 65) Leptoplastides from the early
Ordovician shales of Shropshire, U.K. You
can see individuals of more than one size on
this single piece of rock, and about equal
numbers are right way up or upside down.
Most of these individuals are a cm or two
long.

' *^

i

i

^^^^

' -■**■-■ --aj -■-'1

, ..4, ' -.^Ji'.Sfi,-

"k-

r>

10. ABOVE 0/e«e//ws, one of the
oldest trilobites from the Lower
Cambrian rocks - the example illus-
trated is from Pennsylvania, USA. In
spite of its antiquity it has clearly
developed, large crescent eyes. Notice
how the third thoracic segment is
larger than the rest. The pygidium is
minute - partly concealed beneath a
spine towards the rear of the thorax.
Olenellus is often as long as lo cm.

11. RIGHT The tiny blind Agnostiis
pisiformis, a few mm long at most,
from the late Cambrian strata of
England. Cephalon and pygidium
are almost identical in shape and
there are only two thoracic
segments.

/

'\. // -

■»^' .jf '-* ,

12. TOP LEFT The elegant Isotelus from the
Ordovician of New York State. Eight thoracic
segments show this to be a relative of
Ogygiocarella. The outline of the head and tail
match closely - a match that was used during
enrolment. The curved eyes stand proud of
the head. About locm long.

13. ABOVE The blind, medallion-like trilobite
Trimideiis finibrii-itus with its remarkable
'fringe', the function of which remains
debatable. This is a moult - the genal spines
are missing. Specimens are a few centimetres
or long. Ordovician, Wales.

14. ABOVE LEFT The head of an Ordovician
trilobite related to Trimicleus { PwtoUoydolithus)
recovered from a bore-hole in eastern England.
This beautiful trilobite has a symmetrical
'fringe' perforated by a hundred pits.

15. LEFT The giant eyed trilobite Pricyclopyge,
which swam in the deeper waters which
covered southern Wales in the Ordovician
period; Pricydopyge is usually 3-5 cm long.

i6. Derek Siveter's photographs of the Silurian trilobite Calymene from Gotland, Sweden, in
four different views. The forward view shows how the tail is perfectly shaped to tuck up
inside the headshield.

17. A unique antique gold brooch with the Silurian trilobite Calymene as the centrepiece.

18. OVERLEAF

A lateral view of a perfectly
preserved enrolled Phacops
from the Devonian lime-
stones of Morocco. Very
similar species occur in
North America and Europe
and the Far East. The glabella
carries great tubercles. The
eye with its spherical and
slightly sunken lenses is
shown well in this example.

''tt #

. *-•*■

>^,' '■ ^

^*^

CRYSTAL EYES

of logic. Embryologists who study the cell-by-cell growth from
fertilized egg to recognizable organism have been able to develop
techniques of staining tissues which are responding to the bidding
of particular genes. This is how they know that the development of
the standard experimental insect Drosophila proceeds in a similar
fashion to the developing embryos of vertebrates. What they have
discovered is a list of instructions about how to order a body
that operates whatever kind of body is being constructed. The
conclusion follows that the genes that control this sequence of
development must be so ancient that they go back before the last
common ancestor of insect and vertebrate. This is an evolutionary
'split' of such antiquity that it must precede even the oldest
trilobite, because we know for sure that trilobites were already
typical arthropods (like their distant cousins - the fruit flies,
Drosophila). So the common ancestor connecting backboned ani-
mals and joint-legged animals - an animal that must have owned
the right genes in common - must lie further back in time from
the first trilobite fossil. In fact, the split between the arthropod
and the vertebrates is one of the deepest branches on the tree of
life - it is even likely that arthropods are more closely related to
snails than they are to vertebrates. We cannot readily conceive
of this remote ancestry; probably we will never know what that
common ancestor looked like. We can infer that it was small and
soft-bodied, and it will have left no fossils. Nonetheless, its legacy
still tells the developing embryo which cells shall form a head,
and how the body shall be arranged from front to back. It inexor-
ably follows a blueprint originally drawn up in the most ancient
times. It is rather wonderful to imagine this distant manifesto at
work on the growing trilobite, directing the brain to be enclosed
within the head - and, of course, issuing instructions for the
growth and development of eyes.*

For eyes are part of this ancient list of instructions. It seems
that the making of an eye is the same impulse in fish or fly or

* The gene controlling eye development is not a HOX gene, but a homeodomain
gene called PAX6.

81

trilobite!

man. As the cells develop in the embryo there is a point at which
eyes begin to differentiate. They start as a bundle of cells, which
divide, and divide again. The end product may be very different
- after all, insects have compound eyes and vertebrates sophisti-
cated, lensar eyes - but the impulse, the instruction 'make eyes!',
may be common to all animals. The deep language of the genes
is an Esperanto of biological design which can be understood by
a Babel of organisms. The deep-seated genes represent an organiz-
ing principle that predates the extraordinary proliferation of life
that made the living world as rich as it is today: to understand
this deep structure we have to strip away differences to the
commonality of ancestry. The eyes have it.

Maybe this democracy of eyes stretches as far back as the
flatworm, a little, wedge-headed organism that still abounds in
moist places in soils and under stones. Many readers will know
the flatworm only as a clever cipher in one of M. C. Escher's
ever-retreating symmetrical designs. In his drawing, flatworm
interlocks with flatworm into an infinite regress that flaunts geo-
metrical meshing finer and finer until it reaches a kind of reductio
ad absurdum. It is a favourite subject for posters on the walls of
advanced biology classes. The flatworm has a kind of surprised
look - expressed with its eyes - as well it might, being the victim
of such an exercise in facile geometry. Many biologists place the
flatworm (or, to be accurate, several different flatworms) close
to the common ancestry of most higher animals. Hence, the
ancestor of both trilobite and train driver may be a tiny, flattened
invertebrate with minute eye spots. And the instruction that bids
the eye grow in a flatworm may be the same instruction that
instructs it to form in ourselves.

So when you see - with your own eyes - the eyes of the trilobite,
you recognize a kinship of vision stretching across hundreds of
millions of years. It's too bad that the trilobite cannot manage a
conspiratorial wink. The trilobite reminds us of that moment -
at least, a moment in geological terms - when the first organism
developed a cell that was sensitive to light. Then the elaboration

82

CRYSTAL EYES

and proliferation of such cells that followed was sealed for ever
into the blueprint of development for our own sight-dominated
world. Who can doubt that as soon as vision became a realized
possibility it must have conferred on its possessor an exceptional
advantage? Food could be identified by shape alone, and the
approach of enemies would blot out the sunlight. Surely there
must have been a premium on seeing the world more clearly,
recognizing subtler movements, that would encourage the evol-
ution of more and better vision. Now there was a point in paint-
ing-up to attract a mate. Colour would have a purpose. The
delicate deceptions of camouflage, the machinations of mimicry,
the whole of Nature's palette, would follow as a logical conse-
quence. Without that moment of vision, colour in the natural
world would have been haphazard, a splash of red here, a flash
of green or yellow there. Although colours are incidental
properties of many biological molecules, it requires vision to
recruit them into useful roles and to paint the Earth with a
purpose.

As to when this happened, we know that the first trilobites in
the Early Cambrian already had a sophisticated visual system.
The eyes of one of the oldest of all, Fallotaspis from Morocco,
are quite large. This animal dates firom approximately 540 million
years ago, hence the origination of eyes must have been before
that. Several of the soft-bodied animals from the Chengjiang
fauna of the early Cambrian of China also had eyes - some of
them on stalks. Arthropods like Fuxhianshuia seem to have their
eyes positioned far forwards, whereas trilobites, of course, carry
them on top of the head, within the shield. So it is clear that
there had already been a lot of evolution of variety in eyes among
the jointed-legged animals almost at the inception of the Cam-
brian. Whether or not this happened in a burst of accelerated
evolution - the Cambrian 'explosion' - is a subject to which I
will return. For the moment we can say that solid fossil evidence
that cannot be misunderstood proves that eyes originated before
- and probably well before - 540 million years ago.

83

trilobite!

An estimate of when the first eyes might have originated in the
Precambrian can be obtained in a different, indirect fashion.
Recall that body fossils, actual organic remains, are rare in Pre-
cambrian rocks, and of animals with eyes there is no really solid
evidence. Perhaps these animals were very small and soft-bodied:
they certainly lacked the hard and readily preservable shells of
their trilobite successors. We have to do without direct evidence,
and infer distant events from effects that linger on even in living
animals. Since we know that animals descended one from another,
we would like to know when one, basal group of eyed animals
'split off' on the tree of life from their eyeless relatives. The
eye-bearing animals in question may have taken very different
paths subsequently - to have become as unlike as a whale and a
flea, or an octopus and an orangutan. This is of no concern in
the question of origins. What we are interested in is dating the
branch in the road map of evolution where the different routes
were initiated - this is called the 'divergence time'. It v^ll be
important to learn when 'higher' animals split off from the flat-
worms, carrying with them message to 'make eyes!' that still
operates its imperative. The divergence time can be guessed at
by summing up the changes that have accumulated in the genetic
code after the split occurred. Mutations happen, and such changes
gather in the genetic code like bad memories stocking a guilty
conscience; the effect is cumulative. These accreted mutations can
provide a kind of clock, which can be reckoned in terms of
millions of years if the right part of the genome is examined.
There are 'fast' clocks and 'slow' clocks, and to try to look back
into the Precambrian we need almost the slowest clocks of all,
located in parts of the genome that are enormously conservative.
We need to look for the genetic Collective Unconscious shared
by all animals.

There are some parts of the genetic code which have proved
particularly useful in trying to date distant evolutionary events.
Inside every living cell there are large numbers of tiny particles
called ribosomes; they are where life-giving proteins are synthes-

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CRYSTAL EYES

ized. About 60 per cent of the ribosome is composed of
ribonucleic acid (RNA). Parts of the ribosomal RNA molecule
have been claimed to have just about the right degree of con-
servatism to measure and calibrate the changes in which we are
interested - neither so 'slow' as to have remained for ever un-
changed, nor yet so 'fast' as to have run around the clock more
than once. This vital molecule is possessed by all the animals
with which we might be concerned, and so the genetic changes
that have accumulated over hundreds and thousands of
millennia permit a common time calibration. However, the
claim that RNA 'clocks' are reliable is still controversial, and
many of my colleagues wonder how much 'noise' there is in
the signal, that has nothing to do with the ticking of geological
time.

Over the last ten years or so (I write in 1999) there has been
a large number of estimates of divergence times based on a variety
of genes and different 'bits' of the RNA molecule. Recently, as
the enormous, cryptic library of the DNA molecule itself has
gradually been decoded, other evidence has been brought to bear
on the question of divergence times. Some of those genes which
code proteins, and the DNA found in the mitochondria of the
cell, have been used as 'clocks' to check on ancient genetic legacy.
What convinces me that there is some truth in estimates of deep
Precambrian divergence times is the fact that many of the diver-
gence times are within the same order of magnitude. Many unsat-
isfactory estimates have been recognized and rejected. It is like
walking into an old-fashioned horologist's shop with no idea of
the time, and through the cacophony of ticking and murmuring
of electric pulses seeing that some of the clocks are clearly dancing
to their own music of time, while a majority are reading some
time about half past two. You could not be certain of the exact
time, and certainly not that it was half past two, but you could
feel pretty sure that it was not before one o'clock, nor yet teatime.
So with the molecular 'clocks'. It seems likely that the far distant
common ancestor of the line that led to starfish and man on the

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trilobite!

one hand, and trilobite and fly on the other,* Hved at some time
between 750 million and 1250 million years ago - after lunch in
the history of life, but before teatime. This common ancestor
probably carried a pair of primitive eyes.

If this figure is even approximately correct, it places trilobites
more than 250 milUon years after the origin of eyes, and quite
possibly at about 500 million years. Trilobites offer visible evi-
dence of the halfway stage in eye development, a testimony to
the continuity of the genes that still intervene in the development
of every embryo. Inspired by our modern genetic knowledge, we
can feel a bond with the trilobite that would not have been
apparent when the nineteenth-century investigators first looked
into those stony eyes. To these earlier scientists, the trilobite was
an alien creature, whose connection to the world of living animals
was remote, almost imponderable. They might have perceived
some thread of common ancestry, but I doubt that they intuited
that aspects of the design of a trilobite were perpetuated in our
own embryos. An advance in knowledge has served to entwine
us closer with the past. 'Look into my eyes,' the trilobite seems
to say, 'and you will see the vestiges of your own history.'

This shared history of vision is far from trivial. In our visually-
dominated world sight is almost synonymous with understanding.
We acknowledge light dawning by saying: 'I see!' The metaphor
of vision suffuses our attempts to convey comprehension: we
bring issues into focus, we clarify our views, we sight our objec-
tives, we look into things. We accept the evidence of our own
eyes. The conjurer turns the veracity of sight head over heels:

* This is correctly known as the join between the Protostome and Deuterostome
animals. The former includes all the arthropods, as well as molluscs and many
worms, while the latter comprises the vertebrates (including us) and echinoderms
(sea urchins and relatives). The distinction between these great assemblages of
animals was recognized by nineteenth-century embryologists as a fundamental dif-
ference in body development; it has stood the test of a century of biological investi-
gation and, more recently, molecular analysis. Recently, the Protostome idea has
been refined by the recognition of a large group of animals that have moulting
hormone.

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CRYSTAL EYES

now you see it - now you don't. We find his tricks disturbing
because we are so wedded to the truth of sight. To understand
the deep history of vision gives us a way of perceiving how even
the most distantly- related animals, far off in remote geological
time, managed to comprehend their world. We can describe how
they understood their vanished seascapes in terms that we can
still apply to our own habitats, a compound of sight, images and
colour. For us to see that the trilobites once saw, too, is to bring
them within the compass of our own understanding.

Trilobite eyes are made of calcite. This makes them unique in
the animal kingdom.

Calcite is one of the most abundant minerals. The white cliffs
of Dover are calcite; the bluffs along the Mississippi river are
largely calcite; the mountains stacked like giant termite mounds in
Guilin Province, China, are composed of calcite that has resisted
millennia of weathering. Limestones (which are calcite) have been
used to build many of the most monumental and enduring build-
ings: the sublime crescents of Bath, the pyramids of Gizeh, the
amphitheatres and Corinthian columns of classical times.
Polished slabs composed of calcite deck the floors of Renaissance
churches in Italy, still grace the interiors of Hyatt - Regency
hotels, or conference halls, or wherever architects wish to suggest
the dignity that only real rock seems to confer. Rubbly limestone
builds our rockeries; its finer, whiter counterpart provides the
raw material from which great sculpture grows. Only silica sand
seems as ubiquitous. Surely one could expect no surprises from
a substance so common and so familiar. Yet it was calcite trans-
formed that allowed the trilobite to see.

The purest forms of calcite are transparent. In building stones
and decorative slabs it is the impurities and fine crystal masses
that provide the colour and design: the yellows and greys and
fine mottling. The dark red of the scaglio rosso so typical of Italian
church floors is a deep stain of ferric iron. Purge calcite of all
these impurities and it is colourless. But it may not be transparent

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trilobite!

even then. Chalk is almost pure calcite, but it is a mass of tiny
grains - fossil fragments most of them - which scatter and reflect
the light: hence its almost indecent whiteness. When the Seven
Sisters on the southern English coast emerge from a sea mist it
is like observing a line of undulating starched sheets, so frigid is
their purity. But when a calcite crystal grows more slowly in
nature, then it may acquire its perfect crystal form, and be glassy
clear. The chemical composition, calcium carbonate (CaCO,), is
simple as minerals go. As the crystal grows the constituent atoms
stack together in a lopsided way, and do not allow other stray
atoms to intrude to cloud its mineral exactitude. Layer builds on
layer to reveal the crystalline form, the macrocosm of the gem
reflecting exactly the microcosm of atomic sructure. As with the
handiwork of a master mason, there is no mistake permissible in
the atomic brickwork. Large, fine crystals often grow in mineral
veins. These are often rejected by miners in search of rarer booty,
for precious metals sometimes hide in grey and opaque minerals
that seem dull by comparison with calcite's perfectly formed spar.
Some of these crystals are sharply pointed and then are described
as dog's tooth spar, looking much like the zig-zag ornament
favoured by Norman craftsmen over church doors; others, blunt-
tipped, are termed nail head spar. But the clearest crystal, trans-
parent as a toddler's motives, is Iceland spar.

Look into a crystal of Iceland spar and you can see the secret of
the trilobite's vision. For trilobites used clear calcite crystals to make
lenses in their eyes; in this they were unique. Other arthropods have
mostly developed 'soft' eyes, the lenses made of cuticle similar to
that constructing the rest of the body. Within this limitation there
is enormous variety: many-lensed eyes like those of the fly; large
complex eyes such as those of most spiders; eyes that can see in
the dark; eyes that function best in brilliant sunshine. The octopus
among the molluscs has an eye that is famously like that of back-
bone-bearing animals, and provides one of the best examples of
convergent evolution in the animal kingdom. Most of us will have
contemplated the sorry eyes of a dead fish, and remarked the com-

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CRYSTAL EYES

parison with our own, large, focusing eyes. Trilobites alone have
used the transparency of calcite as a means of transmitting light.
The trilobite eye is in continuity with the rest of its shelly armour.
It sits on top of the cheek of the animal, an en suite eyeglass, tough
as clamshell.

The science of the eye demands a little explanation. It all
depends on the optical properties of calcite, and this depends in
turn on its crystallography. If you break a large piece of crystalline
calcite it will fracture in a fashion related to its fine atomic struc-
ture: such cleavage of the mineral does the bidding of the invisible
arrangement of matter itself. You are left with a regular, six-sided
chunk of the mineral in your hand, termed a rhomb. Neither
foursquare like a cube, nor rectangular like a chunk of chocolate,
the sides of a rhomb lean away from the perpendicular. The
geometry of mineral shape can be described quite simply by the
orientation of a few main axes passing through the centre of the
crystal: the simplest case is the cube, in which axes passing
through the centre of the faces and meeting at the middle are all
at right angles and all the same length. These axes are termed fl,
b, and c, respectively, a case of science for once taking the simplest
route to make a name. In the structure of calcite, one major axis
has three axes perpendicular to it set at 120 degrees ft-om one
another, hence the configuration of the rhomb. The clear calcite
of this not-quite-a-cube treats light in a peculiar way. If a beam
of light is shone at the sides of the rhomb it splits in two; this is
known as double refi-action. The rays of light so produced are
the 'ordinary' and the 'extraordinary' rays: their course is deter-
mined, just like the shape of the rhomb, by the stacking of the
individual atoms. There is a huge specimen of Iceland spar on
the first floor of the London's Natural History Museum through
which you may peer to see two images of a Maltese cross, one
generated by the extraordinary, and the other by the ordinary
rays. But there is one direction, and one direction only, in which
light is not subjected to this optical splitting. This is where a ray
of light approaches along the c crystallographic axis; from this

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trilobite!

direction it does not split into two rays at all but passes straight
through.

The way that calcite treats light might have remained no more
than an odd fact to be trotted out as an esoteric answer in
tests of general knowledge. But what the selectivity of the c axis
guarantees is that light approaching from the angle at which it
points is specially favoured. If a crystal is elongated in parallel to
the c axis into the shape of a prism light will still pass unrefracted
through the crystal along the long axis of the prism. But light
approaching the same prism from other angles will be split
into ordinary and extraordinary rays, which will in turn be de-
flected to reach the edge of the prism, where they might be partly
internally reflected, or refracted yet again. When the prism
is long enough the only light to pass clearly through to the far
side of the prism is that which approaches from the direction of
the c crystallographic axis. To put it the other way round, the
light that such a crystal 'sees' approaches from one particular
direction. It is an astonishing fact that trilobites have hijacked
the special properties of calcite for their own ends. They have
crystal eyes.

The eyes of trilobites are composed of elongate prisms of clear
calcite. Most eyes have many such prisms stacked side by side.
By comparison with dozens of other kinds of arthropods the
prisms obviously functioned as individual lenses, in just the same
way as a fly's eye is a honeycomb of hexagons, each one a lens
- or the dragonfly's, or the lobster's. The trilobite carries on its
head another example of such an arthropod compound eye - an
eye composed of numerous small ocular units, which had to
collaborate to paint a portrait of the world. Each component unit
is a lens. The unique difference is that the trilobite's lenses are
composed of a rock-forming mineral. It would be no less than
the truth to say that the trilobite could give you a stony stare.
One is reminded of the strange lines from that strangest of Shake-
speare's plays. The Tempest.

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CRYSTAL EYES

Full fathom five thy father lies:
Of his bones are coral made:
Those are pearls that were his eyes:
Nothing of him that doth fade,

But doth suffer a sea-change
Into something rich and strange.

If to travel back to the time of the trilobite is a historical sea-
change then there can be nothing stranger than the calcareous
eyes of the trilobite. And pearls are chemically the same as the
trilobite's unblinking lenses, being yet another manifestation of
calcium carbonate, although pearls are exquisite reflectors of light
rather than transmitters of it. The weirdness of Shakespeare's line
results from his suggestions of pearly opacity, the hints of a corpse
transformed; dead, yet seeing. The trilobite saw the submarine
world with eyes tessellated into a mosaic of calcified lenses; unlike
the dead seafarer, his stony eyes read the world through the
medium of the living rock.

Trilobite lenses were orientated so that the c crystallographic
axes ran along the length of the prisms comprising each lens. In
most lenses this axis is exactly at right angles to the surface of
the lens. If you can see the whole surface of an individual lens
(perhaps using your own hand lens) then the chances are that
the lens could look back at you. The lens, of course, can not itself
see. But it permits light fi-om a favoured direction to pass through
it. The average trilobite eye was a stacked mass of tiny, elongate
prisms, each pointing in a subtly different direction. A long,
semicircular eye might have hundreds or even thousands of such
lenses. Some of the lenses might have their c axes pointing for-
wards; some sideways; some backwards. One has to imagine all
the c axes poking out of the centre of the lenses like a battery of
tiny needles. A large eye would carry a veritable hedgehog (or
porcupine) of such imaginary needles: each needle can be thought
of as representing the beam of light that could pass through the
lens, like a host of tiny arrows each with a particular target. Every

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trilobite!

L'S^" C-Axis

How the trilobite's eye works. Rays of light passed
through calcite lenses in the preferred direction
parallel to the major (c) crystallographic axis. The
light receptors lay on the inside of the eye.

arrow of light contributed a small ray of understanding to the
eye, each lens having its own dedicated field of view.

It is very likely that the trUobite eye functioned in the same
way as that of living arthropods with compound eyes. So we
might expect to find at the base of each lens a receptor cell
which could respond to an incoming ray of light. These cells were
evanescent, as fragile as the rocky lenses that lay above them are
permanent. They cannot be preserved as fossUs, but their existence
was surely necessary to turn a mechanical agglomeration of beams
of light into images. Light of itself cannot generate understand-
ing, any more than an image reflected in a pool interprets the
scene it so faithfully duplicates. Information has to be gathered
by nerves, and interpreted by brains. Because of the selective field
of view fi-om each lens the ancient world of the trilobite must
have been perceived as a mosaic, a shuttle of tiny images, overlap-
ping, subtly changed from lens to lens. The resolution of the
image must have depended to some extent on the number of
lenses. A more detailed perception was possible with many lenses
- the more, the better. Hence it is not particularly surprising to
find that some trilobites had an almost unreckonable number of
tiny lenses.

One of the most difficult jobs I ever attempted was to count
the number of lenses in a large trilobite eye. I took several photo-

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CRYSTAL EYES

graphs of the eye from different angles and then made enormous
prints magnified large enough to see individual lenses. I started
counting as one might: 'one, two, three, four' . . . and so on to
a hundred or two. The trouble was that you had only to look
away for an instant, or sneeze, to forget exactly where you were,
so it was back again to 'one, two, three . . .' Teeth were gnashed,
imprecations muttered, deities' names taken in vain. Eventually
I hit upon the notion of pricking each counted lens on the photo-
graph with a pin, so that it wasn't counted twice. The trouble
was moving to the next photograph: what was the last lens that
I'd identified and how did they link from one picture to the
other? Was it that one with the little scratch, or that one a mite
larger than its neighbour? The work was undeniably suitable for
an obsessive with insomnia. I got to a total of more than three
thousand before I vowed that, in future, I would simply estimate
the number of lenses in a bit of an eye, and use my best arithmetic
to estimate the whole number.

Across their many species the number of lenses in trilobite
eyes varies from a mere one to several thousands. No doubt the
effectiveness of the eyes varied accordingly. But, large or small,
they received light along the c axes of the calcite crystal of which
they were made.

This fact carries an interesting corollary. If we know where the
light came from to pass through an individual lens then we also
know exactly where the trilobite could look. Turn the tiny arrows
of the c axes around and they dart out into waters of the marine
world surrounding the trilobite, spearing any object in vision. To
understand what the animal knew of its environment we only
have to sum the lines of vision of its lenses. We can look through
the eyes of the trilobite to see the world as it was observed
hundreds of millions of years ago. Eyes made of pure crystals are
attuned to the images of ancient scenes. Lenses ranked in horizon-
tal lines may just see a horizon, whereas curved eyes with many
lenses may see a wider view. Learn where the lenses face and you
will have a prospect of a trilobite's field of vision.

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TRILOBITE

The first investigator of details of the field of view of trilobite eyes
was Euan Clarkson from the University of Edinburgh. Euan always
refers to trilobite eyes as 'peepers' after the line in the song:

Jeepers, creepers!

Where'd ya get those peepers?

What he did was to mount trilobites in such a way that he could
with great accuracy measure the direction of the pole (c axis) of
each lens. Then he plotted the spread of directions of these axes
on to a stereographic net, which is a way of displaying which
part of the full 360° sphere of vision the trilobite actually utilized.
He saw what the trilobite saw.

The majority of the trilobites that Euan studied did not see all
around them. He proved that many common trilobites preferred
to see alongside. The eyes looked sideways and forwards and
often a little backwards: they glanced askance. But why? The field
of view was directed over the area surrounding the animal, as it
might be a searchlight sweeping over the ground and low bushes,
but unconcerned with the province of the sky. There is a simple
explanation of why their field of view was limited in this way.
Most trilobites lived on and around the sea-floor, and this was
the world they wished to appraise. It was a world where enemies
approached on scuttling limbs across the surface on which they
lived, where potential food may have lain half buried in soft
sediment, or slowly crawled or ambled over the surface of the
mud. A likely mate was a possible neighbour working an adjacent
plot on the seafloor, but deserved a closer inspection, just in case.
A rival might come sidling up at any minute, and needed to be
spotted before acquiring the advantage of surprise. Antennae
swept the water in front of the advancing animal to sniff or taste
any chemical signals born on currents which might complement
the evidence of their own eyes; tactile and olfactory senses played
their age-old complementary role to visual acuity. It was a world
atop the sediment, where most of the events of the day or night
carried on in the same small hemisphere.

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CRYSTAL EYES

The modern equivalent of this world is still present everywhere
on muddy sea-floors - but does not have the sort of glamour to
rate the television coverage of coral reefs. It is a place where a
variety of humble worms process nutrients from the sediment
itself, many more burrow within it, still others stir it up to make
a nutritious soup. It is an environment where innocuous grazers
are hunted by sneak thieves and footpads, where some animals
disguise themselves as seaweeds, still others breed so fast as to
outstrip their hunters. It is a world full of the subterfuge of
survival, all fed by the organic richness of the sediment itself; a
sideways world, where you watch out for your neighbour, for he
may not be what he seems. It is no wonder that the average
trilobite was concerned with its muddy environs: whether it was
hunter or hunted it had to look out across the undulating view,
twitching and perceptive, for its life depended upon it. For most
trilobites their eyes were a key factor in their survival (although
we have met some blind ones). Who can fail to be impressed by
the trilobite's petrified tokens of the triumph of vision one hun-
dred and fifty million years before even the first tentative excur-
sions had been taken by plants towards colonizing the land?

Look closely at a trilobite eye and you will see a honeycomb
of tiny lenses. Like many packed things in nature, the lenses are
mostly hexagonal. They follow the bidding of geometry just as
many corals do, or insect eyes, or even many patchwork quilts.
Where small, similar objects squeeze together cheek by jowl until
they touch and jostle for accommodation they naturally tend to
compress into hexagons. It is a way of equalizing the pressure
for space with all the neighbours. The centres of adjacent hexa-
gons are all equidistant from one another. So the average trilobite
lens is long and thin, a few tens of thousandths of a millimetre
ijj) across, with its c crystallographic axis running along its length,
and is hexagonal. If the eye were perfectly flat, its design would
be as uneventful as that of a sheet of patterned linoleum. But the
geometry of 'bending' a sheet of hexagons around a curved surface
is not straightforward, and you will find the occasional odd-

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trilobite!

shaped lens or a shuffle in the lines of lenses, to make a little
space around a curve. (We all know the compromises that have
to be made when wrapping a football in Christmas paper.) But
even so, some trilobite eyes seem to be astonishingly regular, lines
of hexagons making gentle spiral curves that run obliquely across
the eye from bottom to top.

Euan noticed something else about the construction of the
trilobite's eyes: the smaller lenses were concentrated at the top
of many eyes. The eye surface - known as the corneal surface -
had to be moulted along with the rest of the animal's hard exo-
skeleton as it grew. The eye itself grew in size in harmony with
the rest of the animal: more lenses were added after each moult
as the new skeleton hardened. New crystals were added in from
the top of the eye in a zone of generation. With successive moults
these lenses were incorporated into the main body of the eye,
passed downwards in a graded chain. These differences in lens
size also helped to maintain the regularity of the design across
the curved surface of the eye. It is fiendishly clever (as Hercule
Poirot would to say) that these 'primitive' animals could play
such games with the mineral world in the service of eye
geometry.

We cannot know exactly how the trilobite saw with its crystal
eyes: the nerves have left no trace. It is like finding an artefact
from some remote civilization - we may be able to assume its
general function, but we will never know the thoughts that passed
through the mind of its user. The trilobite will always keep a
certain distance from us; there will be limits on the intimacy we
can attain. What we can guess is that the honeycomb-like trilobite
eye may have permitted comprehension of the world in the same
fashion as the similar compound eyes of living arthropods. Appo-
sition eyes do not form complete images of their surroundings
(some other arthropod eyes have lenses arranged in such a way
that they are able to collaborate and produce a single, complex
image). Densely-lensed eyes of trilobite type are particularly good
at detecting movement. Another animal approaching across the

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CRYSTAL EYES

sediment surface will trigger one lens after another as its image
impinges on different parts of the field of view. If the change is
alarming the trilobite may be stimulated to take evasive action:
maybe to roll up into a baU or to swim away as fast as possible.
To look through the eye of the trilobite is to see the world as
fragmented pieces of information - trilo-bytes, I am tempted to
dub them. The animal was not able to see as we see, but appreci-
ated the world in a thousand fragments of light, as if the brain
were a pointilliste with a palette of prisms.

There is still more to tell of crystal eyes. Although the great
majority of trilobites have eyes such as I have just described, there
are some which are obviously different. One of the commonest
trilobites in the Devonian rocks of New York, Ohio and Ontario,
and also in Germany and Morocco, is the compact beast called
Phacops, which we have already met in the parade of trilobites
in the last chapter. Moroccan Phacops can be bought for a handful
of dollars and they are cheap at the price. If you work in a large
museum Phacops is one of the most ft-equent trilobites to walk
in through the door accompanied by its owner. One greets it as
one might an old friend. It is always a pleasure to point out its
large crescentic eyes, that stand proud of the cheeks like the
retractable headlamps that grace the front of a Porsche. But wait!
There is something peculiar about these eyes. Instead of the lenses
being so minute that it requires a microscope to see them properly
you can discern them quite clearly unaided. To the naked eye
they look like a series of tiny, perfectly formed balls - a real case
of those are pearls that were his eyes. The lenses line up quite
conspicuously in vertical files, often with a little space between
them, and they are stacked in the manner of hexagons, so that
any lens has six neighbours. It is another example of close packing,
and not different in principle from that displayed by lenses of
other eyes. But it is the regularity of the eye that is so striking.
We are accustomed to expect a little sloppiness in nature's designs:
the leopard's spots are hardly mechanically repetitive, no two
snakes have identical zig-zags on their backs. But these eyes seem

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trilobite!

to have been turned out by a machine, neat as billiard balls
arranged in a box. They are obviously something different from
the minutely lentiferous eyes of the usual trilobite. Instead of
averaging many hundreds to thousands, this kind of eye had
lenses which numbered a hundred or so, or could even be counted
on the collective fingers of the average family.

If the trilobite eye is something out of the ordinary, then the
phacopid eye is odder still.* One way to study it more closely is
to cut a section through the lenses, so that the optical properties
can be studied under a high-powered microscope. Even though
the animal has been dead for so long, there is a hint of the
sacrilegious in taking one of these beautiful creatures and cutting
across its head with a circular saw. Those serried pearls which
have lasted inviolate for several hundreds of millions of years,
may now be destroyed in an afternoon.

But sections made in this way reveal strange secrets. First, the
lenses are indeed nearly spherical, or perhaps slightly drop-
shaped. A phacopid lens has a disquieting resemblance to a glass
eye. As a student I once did a labouring job alongside an old boy
with a glass eye, who would pop it out whenever there was a lull
in the conversation, toy with it for a bit, and then pop it back
in again. In or out, it made no difference - he could not see
through it - whereas the schizochroal lens was evidently func-
tional. Nor could it be dislodged and replaced, as it was sealed
in a solid sheet of calcite (although, like everything else on the
trilobite it would have been moulted). Second, there is usually a-
little 'wall' between adjacent lenses, a kind of baffle which stopped
light from one lens overlapping with that of the next. Often, the
lenses are slightly sunken, and the areas between the lens are a
little swollen. The optical arrangement is clearly a very sophisti-
cated structure which quite belies the antiquity of the animal.
This may come as something of a surprise: we might expect
an eye from half-way along optical history to have a slightly

The 'normal' kind of trilobite eye is known in the trade as holochroai; the special
kind that Phacops and its relatives had is termed schizochroal.

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CRYSTAL EYES

Trilobite eyes. The holochroal eye consisting of numerous hexag-
onal lenses (above) - Pricyclopyge, an eye adapted to detect the
smallest movement; the specialised schizochroal eye of Phacops
showing fewer spherical lensesj_each one finely tuned to its habitat.
(Photographs courtesy Euan Clarkson.)

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99

TRILOBITE

slung-together look, or at least broadly to resemble the eyes of
many other lowly animals, as does the run-of-the-mill trilobite
eye. But the eye of Phacops is something unexpected, a sports
coupe in the age of the boneshaker. Not only does it have calcite
lenses, but they are of a singular type.

Surely such specialized eyes must have functioned in a very
specific fashion. In the living fauna there are no really convincing
analogies: one investigator drew attention to the ant-lion larva
which has somewhat similar drop-like eyes - but not made of
calcite crystals. It was an American investigator at the Smithsonian
Institution in Washington, Kenneth M. Towe, who in 1972 dem-
onstrated the efficiency of the phacopid eye lenses in the most
graphic way: he took photographs through them.

When you are a scientific visitor to the Smithsonian Institution,
the National Museum of Natural History, you enter with the
crowds through the public entrance, but then wheel off to one
side to telephone through to your contact behind the scenes.
Within a few minutes you pass through an inconspicuous door
into a different world of cabinets and collections, a cool, scholarly
enclave away from the metropolitan throng. When Ken Towe
worked there his office had a view across the grand avenue to
the FBI building. Visitors to the Smithsonian were taken there
for lunch, an experience so unexciting as to defuse any paranoia
about spooks and fifth columnists. Using the trilobite lens as a
substitute camera lens Ken photographed the FBI building - not
perfecdy, but recognizably. What more curious tribute to J. Edgar •
Hoover than to have his workplace photographed through the
eyes of an ancient fossil! Another photographic attempt success-
fully captured the grinning 'happy buttons' that were in vogue
at the time. It was as transparent as calcite that the phacopid lens
could form sharp images, bringing into focus objects of different
sizes at varying distances. The phacopid lens saw larger pieces of
the world than the tiny lenses of most trilobites, and saw them
clearly. It was an astonishing feat of optical engineering accom-
plished using calcite, the most quotidian of minerals.

100

CRYSTAL EYES

How this trick might have been done was discovered by Euan
Clarkson and Riccardo Levi-Setti not long afterwards. It was
already apparent from the spherical structure of the lenses of
Phacops - and their large size - that some different method was
being used by these trilobites to form their images when compared
with the tiny lenses of their relatives. These were fat, biconvex
lenses, designed to bring beams to a focus. If you hold a clear
glass marble up to the light and peer through it you can get some
idea of the process: you will see an upsidedown world, all bent
and distorted. The trilobite images seem to be much clearer than
that. How could this be? The problem with light travelling
through a convex lens to a focus is that different rays travel
different distances through the lens according to their trajectory
- and in a refractive material like calcite that means that they get
bent to different degrees: the result is a fuzzy focus. Like my old
workmate's glass eye, to be transparent is not enough to see. The
technical term for this fault in design is spherical aberration.

Riccardo Levi-Setti is a nuclear physicist at the University of
Chicago, a place where everyone is almost effortlessly brilliant.
He also has a private passion for trilobites, which he pursues
more vigorously than many a professional palaeontologist. Euan
and Riccardo made an interesting combination: an extravagantly
hairy and amiable Scotsman and a well-groomed and suave
Italian. What they discovered together was that Phacops had
solved the problem of spherical aberration. Euan had made out
a kind of bowl within the individual schizochroal trilobite lens
and at the base of it, and he identified it as part of the lens with
a different structure. In some kinds of preservation this bowl
would weather out separately, so that the eye came to resemble
a series of little dishes. Euan and Riccardo discovered by making
thin sections that in this part of the eye something strange had
happened to the calcite: it had become impure. Some of the atoms
of calcium within the crystal structure had been replaced by atoms
of its closest elemental relative - magnesium. Because the atoms
are so similar, magnesium could sneak in, like a spy in an appro-

101

trilobite!

priate uniform infiltrating an army. Even in the purest calcite
there are a few such hidden agents. The effect of this process
continuing far enough to make 'high magnesian calcite' is to alter
the refractive index, the capacity of the crystal to bend light.
With a wonderful fineness of balance the thickness of the high
magnesian layer varied across the lens in just the right degree to
correct the spherical aberration - for every bend to the left a
compensating bend to the right. This corrective layer was what
made the bowl. The trilobite had manufactured what a modern
optician might term a doublet, wherein two wrongs do make a
right because of the way they are spliced together.

As a grace-note on this discovery, Riccardo noticed that the
trilobite's design had been anticipated by the great seventeenth-
century Dutch scientist Christian Huygens (1629-95) and the
French polymath Rene Descartes (1586-1650). They had sketched
out an optical 'cure' for spherical aberration in a lens which
proposed a compensating bowl designed almost exactly like that
of the trilobite. This may indeed be a wonderful example of Art
imitating Nature, or perhaps rather of Nature anticipating Science
- by more than 400 million years. S. J. Gould commented in an
article in Natural History in 1984 that 'the eyes of trilobites . . .
have never been exceeded for complexity and acuity by later
arthropods ... I regard the failure to find a clear "vector of
progress" in life's history as the most puzzling fact of the fossil
record.' The point Gould makes is that it is hard to see how the
trilobite could have achieved its optical design in a still more
sophisticated fashion; there remains a feeling that arthropods
ought to have learned some cleverer visual tricks since the
Devonian. The notion of progress in life's story is an intellectual
quagmire. It embodies a belief in 'improvement' which is difficult
to defend. Maybe the trilobite should stand condemned for having
perfect eyes while its limbs were decidedly second rate. Or maybe
we should berate it for carrying such a heavy suit of armour,
while at the same time acknowledging its nonpareil peepers. If
you put yourself in the right frame of mind you can imagine the

102

CRYSTAL EYES

Correcting

structure

operative

Sea water

Oriented calcite

Intralensar bowl

Body fluid

Correcting

structure

ignored

Oriented calcite

Focal plane

The drawing made by Euan Clarkson and Riccardo Levi-Setti to illustrate how
the more highly refractive bowl inside the lens of Phacops helps to bring rays
more closely to focus.

trilobite like one of those medieval knights, cumbersome and
unwieldy, however well-protected. We might be able to talk our-
selves into imagining a story of progress whereby sleeker warriors
outclass the lumbering, articulated Sir Phacops. Serve him right!
Progress is the thing!

This is all nonsense, of course. The eye of these phacopid
trilobites is wonderful, and unique, but I do not know how to
measure it against the lustrous eye of the dragonfly, that can so
resolve an image as to snatch a wasp on the wing. I cannot say
that it is better or worse than the eye of those marine crustaceans
who use silvered boxes to focus weak light at depth into a precise
image. I do not know how it stands in comparison with the
several, surprising eyes of spiders. Who is to calibrate progress,
who to legislate on the unit of improvement? The trilobite was
no doubt a perfect citizen of its times, and its eyes focused on
the problems of its daily life sufficiently well to allow the beasts
to throng in their thousands on the sea-floor. The astonishing

103

TRILOBITE

fact is not that the eyes were so perfectly engineered but that
the sea rewarded such a specification even then. We cannot
name a time when the trilobites reached their acme, after
which there was either stasis or decHne. Life just isn't Hke
that.

My own engagement with trilobite eyes was an investigation
of goggle-eyed species. One of the most peculiar specimens I had
discovered in the Ordovician rocks of Spitsbergen was quite unlike
other trilobites that I had seen illustrated in textbooks. It was
long and thin, and the axis occupied much of the body, so that
the pleurae were reduced to little triangles. But the eyes were
truly extraordinary: they were enormous and inflated, puffed up
like little bladders. It was weeks before I was able to convince
myself that I had located the correct free cheek for this trilobite
(I had no entire specimens, so it was the usual matter of complet-
ing the jigsaw puzzle). But in the end there was no question: the
eye had become so enormous that it abutted against the edge of
the cranidium in an almost straight fine running alongside its
entire length. Only one eye among the selection I had cracked
out from the Ordovician limestones had the right 'fit'. I was now
able to place the eyes back in position on the headshield to
reconstruct the skeleton of the entire animal. Now it seemed even
odder. It was obvious that the eyes bulged out on either side of
the head in the manner of those slightly grotesque ornamental
goldfish that have such a thyroidal look; in proportion these
'peepers' were even larger - virtually the whole free cheek had
turned into an enormous eye! What could be going on? I named
this strange animal Opipeuter inconnivus-, having recruited the
help of a classicist friend to find out the Greek for 'one who gazes'
- Opipeuter, inconnivus means 'without sleeping'. Trilobites, of
course, were unable to blink.

There were some other details that attracted my attention.
When the eyes were 'fitted on' it was perfectly clear that they
hung down well below the level of the rest of the animal. If you
view the majority of trilobites from the side the base of the animal

104

CRYSTAL EYES

makes a line parallel with the sea floor on which they lived; not
so Opipeuter. Furthermore, the edges of the cheeks were sharp,
with their cutting edges directed downwards. This is where Euan's
work on the direction in which crystal lenses could see became
so useful. The lenses on Opipeuter were tiny and of the crowded,
hexagonal type used by most trilobites, not the special Phacops
type. Hundreds upon hundreds of lenses crowded together over
the bulging surface of the eyes. But they differed from the
crescent-shaped eyes of nearly all the trilobites I had ever seen,
that looked predominantly sideways across the sea bed. In
Opipeuter there were lenses that faced sideways, of course, but
there were also many dozens of lenses that 'looked' forwards. If
I was right about the bulging orientation of the eye, there were
nearly as many lenses that were capable of looking upwards as
well - and even downwards. And with the thorax so trimmed at
its edges it was likely tljat the eyes projected out far enough to
command a view backwards . . . there were lenses gav^ing every
which way. These weren't just peepers, they were more like
oglers.

Surely this trilobite needed to see all around, but what could
it possibly be for? Where in the ocean is it necessary to have an
all-encompassing view of the watery world? Perhaps it was my
customary view of trilobites as bottom dwellers that prevented
me from seeing the obvious. It must, of course, have been a
swimmer! A leap of the imagination had the trilobite leaping off
the sea floor. Opipeuter had the freedom of the Ordovician oceans:
it needed to see everything. Suddenly there was a different vision
of the lives of trilobites: from grovelling on the sea bed, they
filled the seas as well. The former oceans could have swarmed
with trilobites, just as krill throng in living seas. That was why
the body of Opipeuter was long and thin compared with most
trilobites, and why its design was so poor for resting on the sea
floor. It had a vaulted axis to house the muscles used to power
its swimming limbs, but economized on the rest of its shell so
as not to overburden the work of the sculling appendages. Some

105

TRILOBITE!

My reconstruction of the giant-eyed Ordovician trilobite Opipeuter - swimmer
across the ancient oceans, from the top and the side.

of the rocks in Spitsbergen were almost made of this trilobite
and its relative, Carolinites, so that it was not hard to imagine a
sea alive with thousands of these little animals, swimming in the
brilliant sunlight while, far below on the sea-bed, Triarthrus slowly
ambled through the soft mud.

There proved to be a number of different trilobites with this
free-swimming design; the one-eyed Cydopyge had been noticed
already as a swimmer by the great early twentieth-century geol-
ogist Eduard Suess. He made a comparison with some huge-eyed,

106

i

CRYSTAL EYES

living crustaceans. When I discovered this observation, buried in
the middle of his great work The Face of the Earth, I understood
that ideas are seldom ever really new. Cydopyge was a more
compact animal than Opipeuter, with fewer thoracic segments,
but it lacked nothing in the eye department. It, too, was found
in considerable numbers in company with several other genera
of bug-eyed trilobites. I have studied these cyclopygid trilobites
in Wales and Bohemia. They were collected from dark mudstones
that were originally deposited in relatively deep water, to which
they are apparently confined. I have sat under hedgebanks with
rain dripping down my neck breaking open dark shales near
Carmarthen - in Welsh, 'Merlin's Castle' - and could not have
been more amazed if the old magician himself had popped out
of the undergrowth than by my first sight of the fat eyes of
Pricyclopyge, staring out at me after an incarceration of 470 million
years, some of its lenses still glistening slightly. In contrast, many
of the limestones which yielded Opipeuter and Carolinites were
laid down in shallow seas - there were other fossils with them
that proved it. Could it be that Cyclopyge and its friends swam
at depth in a world of pervasive dimness, while Opipeuter and
its allies lived in the surface waters of the sea in brilliant light?

I was able to test this idea thanks to a grant of money from
the Leverhulme Trust. It is fortunate for me that a few charitable
bodies still exist who will support what has been called 'blue skies'
research - that is, research that has no industrial or commercial
spin-off. I doubt you can get bluer skies than trying to find out
about the optics of Ordovician oceanic trilobites. Leverhulme
supported a young post-doctoral assistant, Tim McCormick, to
immerse himself in trilobite eyes for several years. We had dis-
covered that it was possible to deduce the light intensity in which
an arthropod customarily lived by making some very careful
measurements on the compound eyes. This had been worked out
on a variety of living species - and it seemed a good idea to try
it out on trilobites. Tim had to mount perfectly preserved speci-
mens so that he could measure such details as the distance and

107

trilobite!

angle between adjacent lenses, so as to obtain a mathematical
quantity termed the eye parameter. It was a labour that lasted
for six months. Imagine our delight when our alleged surface
swimmers came out with the right value for bright illumination,
and the trilobitic Cyclops condemned itself to live in gloom. Thus
we were able to insinuate ourselves into the daily lives of our
favourite animals. We had no Steven Spielberg to animate these
creatures into plausible simulacra. Our vision of trilobite lives
remains lodged in our own imaginations, but all the more intense
for that. Now we can visualize an Ordovician sea with a clarity
that would have astonished Adam Sedgwick, lames Hall or Sir
Roderick Murchison. We can see - literally, through the eyes of
the trilobite - an ocean teeming with swimming animals, some
grazing on tiny zooplankton near the surface, others deep down
in a twilit world, and both above a sea-floor where a profusion
of other trilobites again scurried or ambled.

Nor was this the end of our vision. Among the small, deep-
water cyclopygids, there were rare examples of a different and
larger kind of animal. This trilobite, too, had big eyes, but they
did not bulge out; instead they were tucked into the side of the
head. And what a peculiar cephalon! It was extraordinarily long,
largely because it was produced forward into what can only be
described as a snout or nose. This 'nose' comprised the front part
of the glabella (which was itself unusually smoothed out, and had
lost all its furrows) and an extended section of doublure beneath
it; together they made something that looks like the 'nose' of a
dogfish or small shark. The rather large pygidium had a dished
appearance. The whole thing was beautifully smoothed out, like
a torpedo. The shape of the animal reminded me of an illustration
I had once seen in a textbook of an idealized hydrofoil - a shape
designed to cut through the water with a minimum of frictional
resistance. Could this trilobite have been the porpoise of its kind?
I needed advice.

Just up Exhibition Road from the Natural History Museum is
the famous Imperial College of Science and Technology. Imperial

108

I

I

CRYSTAL EYES

has long been one of the leading institutions for all the sciences
that make things work: somewhere there there must be a B & Q
Professor of Gadgetry. I soon learned of a lecturer called David
Hardwick who could help me design an experiment to test the
streamlining of my dogfish-nosed trilobite (which goes by the
inelegant name of Parabarrandia). In the hydraulics department
there were all manner of flume tanks and watery experimental
gear. The simplest thing that could be done was to suspend
life-sized models of various trilobites in a transparent-sided tank,
along which a current flowed. If you then streamed a dye into
the tank you could see which animal shapes produced the best
streaming past the body. Most of the models we tried had all
kinds of turbulent wakes: projecting eyes, for example, showed
little coloured eddies behind them. Now we could see why it was
an advantage for Parabarrandia to have its eyes flush with the
sides of its body. In fact, the dye streams flowed past this trilobite
as if they were long, straight tresses swept out in a breeze: it was
a wonderful demonstration of the streamlining theory. We could
now imagine this animal elegantly outpacing all other swimmers
in the Ordovician. But we needed proof to convince our sceptical
colleagues. So we now went further by designing a way of measur-
ing the drag itself, by seeing how far carefully scaled models
were deflected when suspended in a gende current - the poorly
streamlined species would experience the greater deflection as
their bodies offered resistance to the movement of the current.
This required an experiment in an open-topped tank. The trilo-
bites were suspended in the tank as if they had been bait for
some Palaeozoic fisherman. Now the current was turned on, and
the deflection measured with a travelling microscope. In a white
lab coat and with my sensitive measuring equipment I felt like a
real boffin.

I nipped out for a quick cigarette (I was a smoker then) while
the experiment was still running and was horrified when I
returned to find the whole laboratory floor several feet deep in
water. I had visions of being banned from Imperial College for

109

trilobite!

The free swimming trilobite Parabarrandia (Ordovician, Czechoslovakia)
immersed in a flume tank. The stream of dye to the right shows the excellent
stream-lining.

ever, and having my screw^driver confiscated by the B & Q Pro-
fessor. Mortified, I sought the aid of the laboratory technician.
Giving me that look which I have often received from garage
mechanics, he waded into the middle of the floor and pulled out
the most enormous bath plug I have ever seen. Within minutes
the water had gurgled away down the plughole, while I stood by
with my mouth hanging open slightly, damply rueful. But the
experiment had proved the point. There were streamlined trilo-
bites that sped through the Ordovician ocean.

It is a curious fact that, despite the beauty and complexity of
trilobite eyes, it seems curious that plenty of trilobites could do
perfectly well without them. A large number of them were blind.
Eyes, apparently, could be readily jettisoned. In some examples
we can even show how it happened. An ancestral species had
large eyes, and a succession of daughter species had smaller and
smaller ones, until the facial sutures ran across the cheeks leaving

no

i

CRYSTAL EYES

no sign of lenses at all. Some of the trilobites related to Trinudeus
had just one lens left perched high on the cheek. My colleague
Bob Owens from the National Museum of Wales and I collected
some localities in South Wales where ten or more blind, or nearly
blind, trilobite species lived together, and they must have crawled
about the sea floor in a dark world. Appropriately enough, the
quarry from which we collected them was also profoundly
gloomy, the muddy Ordovician rocks from which the trilobites
emerged sooty black - and probably always had been from the
time of their deposition. So we were finding black trilobites that
lived in perpetual darkness in a dim quarry full of black rock.
My eyes have never really recovered. Even odder, the other trilo-
bites in the same rocks were huge-eyed swimmers. It did not take
us long to deduce that the swimmers swam well above the lightless
sea floor on which the blind animals dwelt. They joined one
another only in death. Eyes were lost because they were surplus
to requirements. These trilobites had an affinity with blind cave
crustaceans, new species of which are discovered every year: pallid
creatures, in which pigment has bled from the body and light
from the eyes. When they are brought to the surface, they look
diseased, like tubers stored too long in the cellar. They are not
ill, of course, merely drained of superfluities which are not neces-
sary for their dim existence.

Blind trilobites were not confined to the deeper seas, although
they were probably commonest there; others may well have been
burrowers, for example. Nor would it be correct to think of them
as degenerate. I was brought up in a tradition of thinking of
animals in their geological history reaching some kind of acme,
and afterwards - those that ultimately went extinct, in particular
- having a phase of decline. There was, inevitably, the image of
human frailty blended with this. Blind or otherwise specialized
creatures might be described as degenerate, almost in the way of
the Victorian black sheep of the family who contracted unname-
able diseases and squandered the family fortune. I must confess
that I once found something about this scenario attractive, and

111

trilobite!

not merely because it dramatized episodes in the history of life
in novelistic terms. It tied in with some inaccurate notions of
Darwinian 'fitness', too. Some animals were destined for (literally)
blind alleys from which they never emerged. Other, fitter, ones
prospered and brought forth evolutionary progeny. Curiously, it
is true that I know of no example of eyes once lost and then
regained. It is certain that trilobites primitively possessed eyes -
their loss is always therefore a secondary adaptation; and, like
virginity, sight can never be regained once it is lost. But the
important point is that all blind trilobites were excellent citizens
of their time. Sometimes they outnumbered their sighted cousins.
In Shropshire, England, there are soft, greenish shales that crop
out in the banks of Sheinton Brook, near the odd-looking hill
known as The Wrekin, which are covered with the remains of
the blind trilobite Shumardia, a perfect little miniature with only
six thoracic segments and a glabella shaped exactly like the ace
of spades. The same animals are abundant in Ordovician shales
in Argentina; and I collected them again in southern China,
equally in their hundreds. No dissipated roues these - they clearly
spread around the Ordovician world in their millions. If there is
a moral to draw from this it is that what we describe as adaptive
success is also about the opportunities presented by the environ-
ment, lust as the ingenious inventiveness of the trilobite eye
opened up a range of habitats so that they could hunt or swim
in the open sea, even the loss of that same organ could quahfy^
the animals to prosper in a sea-floor of soft mud. The glorious
richness of the natural world is about multiplicity of adaptations,
and it was so from the time of the trilobites.

The story of trilobite eyes I have related illustrates, appropri-
ately enough, the principle of progressive illumination. This is
the way science often works. As we learn more, we think of
new questions to ask. We proceed from calcite to calculation to
something like certainty. Imagination plays its part, of course,
but our appreciation of vision is not, as Samuel Taylor Coleridge
said, A sight to dream of, not to tell, for we try to convert our

112

CRYSTAL EYES

dreams into the solid stuff of published scientific articles. Advance
in knowledge was dependent first upon recognition of the differ-
ent kinds of eyes, and then of the ways they might have worked.
At root, this is another form of taxonomy, another expression of
humankind's talent for discrimination. Nor does the process
come to an end. As I write this, a paper has just arrived from a
Hungarian scientist suggesting that some trilobites may have had
bifocals! I do not know yet whether this idea will pass the criticism
of the next generation of investigators. What I do know is that
there will be more to find out about trilobite eyes. That combi-
nation of imagination and rigour which is what science is all
about, has not yet probed out all the secrets: there is sight, and
there is insight.

113

V

Exploding Trilobites

The play's the thing! As the theatre curtain rises we butt into the
hves of the characters without preamble. There is no biographical
account of the dramatis personae printed in the programme notes,
describing their lives before they are presented to us on stage.
We expect no more history than is given to us in the three hours
or so that we occupy our seats. If it is a good play, as with
any work of art, the experience will be satisfying within its own
boundaries - we won't be left fretting to know about the early
history of the characters, any more than we will demand that
Macbeth overcome his remorse and next time triumph over his
foes.

Drama is often used as a metaphor in the history of life. Ani-
mals have been described as 'actors' on the ecological 'stage'.
Mass extinction events that have interrupted more routine oscilla-
tions of fortune, the stuff of everyday evolution and decline, are
'dramatic' interruptions in the 'narrative'. This kind of description
engages the attention more readily than strictly scientifically-
correct statements about 'statistically significant elevations of
extinction above background rates'. Well, what's wrong with a
little theatre? There will have been episodes in the history of life
as dramatic in their way as that instant above the sea where
Stephen Knight faced the trilobite and transformed his destiny.
A long view of life does indeed see dramatic twists, where roles

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EXPLODING TRILOBITES

are reversed - as when mammals replace dinosaurs centre stage
- or one old stager is replaced by another in a familiar part. I
have heard it said that trilobites once played the ecological role
now taken by crabs and lobsters, and most people with a passing
knowledge of natural history will know that ichthyosaurs have
been described as the porpoises of the Jurassic. We will let it pass
that neither of these nostrums is exactly true.

When a play (particularly a whodunnit) is beginning to stall
a little, one standard bit of theatrical 'business' to bring it alive
is to introduce an explosion. Boom! The audience jumps to atten-
tion; and, of course, under the cover of gun-shot it is possible to
get away with murder, dramatically speaking.

Fossils of trilobites appeared suddenly in the geological record
during the early part, but not quite at the base of the Cambrian
period, perhaps 540 million years ago. If you are tempted by the
word 'dramatic' then this is one occasion where you could be
forgiven for weakening. When you visit a rock section spanning
the right bit of the early Cambrian - and there are such profiles
in Newfoundland, Mongolia and Siberia - there will be not a
sniff of a trilobite as you work your way upwards from one bed
to its successor: this is the most methodical way to trudge upwards
through geological time. Then, quite suddenly, a whole Profallot-
aspis or an Olenellus as big as a crab will pop out into your
waiting hands as you split the rock. These are trilobites with lots
of segments and big eyes: striking things, not little squitty objects.
It is an appearance as dramatic as that of the sorcerer in Swan
Lake, who accompanied the first theatrical explosion I ever experi-
enced. You are tempted to cry out: 'bang!'. And as you continue
to collect a foot or so higher into younger strata, the first trilobite
will be joined by others, maybe half a dozen or so different
species, and all individually distinctive ones at that.

More than a decade ago I examined the trilobitic early Cam-
brian rocks on the island of Newfoundland. Its Northern Penin-
sula sticks up as stiffly as an abusive finger on the western side
of the island. There is only one road running northwards up the

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trilobite!

Peninsula* from Deer Lake to St Antony. After less than an hour
on this road you enter the Gros Morne National Park. The road
winds alongside Bonne Bay, a beautiful, huge, drowned inlet into
which the surrounding hills plunge somewhat recklessly. The
valley which is now occupied by Bonne Bay was long ago exca-
vated by a river, but the rise in sea level at the end of the last
Ice Age drowned it, so that now the sea probes impertinently
into its every corner. Firs and aspen and birch vie with scrubby
alder to make the inland almost impassable on foot. Blackflies
and mosquitoes are further discouragements. The road loops and
curves, not allowing any driver to take his eyes off it for long.
Strata have been sliced through to make the road passable: they
were folded in such a way that they now plunge at various angles
into the sea. On a great, flat brown bedding plane of rock some
foolish exhibitionists have painted their initials a foot or so high in
white paint: 'RW luvs SDM'. What they should have written is:
'Amazing trilobites found here!' But any such search would have
to be frustrated, because Parks Canada have strict rules about col-
lecting by permit. If you do have permission, as I did, you can break
open shales to your heart's content, and if you are lucky you will
be rewarded with a big, juicy Olenellus, or you may find fragments
of another trilobite like Bonnia - presumably named after the Bay.
On the other hand, you may well discover completely different
kinds of fossUs: I recall that I found a fine specimen of a very primi-
tive echinoderm (the group which includes starfish and sea
urchins) called Protocystites walcotti - no prize for guessing after
whom it was named. Nearby, a small mollusc turned up.

The early Cambrian level is like this almost everywhere. A
variety of shells can be found, some of which can be placed with
their living relatives in one or another of the great 'phyla' - the

* Newfoundlanders are often humorous and hospitable people. They have been
used as the butt of jokes by mainland Canadians, allegedly for their lack of sophisti-
cation. The only instance I can recall of a real 'Newfie joke' was when I was leaving
the Gros Morne Park in search of food. At the inn at Cow Head a laboured hand
had scrawled a notice in jagged chalk letters; 'Cow Head MOTEL best food on the
whole PENISULA'.

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EXPLODING TRILOBITES

major divisions of the animal kingdom, like Mollusca, Arthropoda
or Echinodermata. The Cambrian strata which lie below those
including the first trilobites often yield a variety of small shells,
tubes, plates and nets sculpted into a host of shapes, many of
which def)' ready recognition as any part of an animal we know
about. They are collectively referred to as 'small shelly fossils'. It
has recently been shown that the variety of these may be more
apparent than real, because Simon Conway Morris and John Peel
have proved that many different 'small shellies' belong together
to make up a much larger, plated organism, called Halkieria. The
little plates may be no more than the components of a kind of
chain mail. But what is real enough is the sudden appearance of
shells - hard parts, skeletons, call them what you will. Animals
contrived to use minerals to support their soft anatomy over
(geologically speaking) a very short period of time at the base of
the Cambrian. Not only that, there is now a number of fossil
faunas from the Cambrian that exceptionally preserve animals
without hard skeletons - those soft-bodied animals which are
generally so rare in the fossil record.

The most famous of these localities is the Middle Cambrian
Burgess Shale in British Columbia, arguably the most illustrious
fossil deposit anywhere in the world, thanks to S. J. Gould's
account of its treasures in Wonderful Life (1989). But fossil faunas
have now been recovered ft^om even earlier - Lower Cambrian
- rocks which are almost as diverse. Those discovered in Chengji-
ang in China and Sirius Passet in Greenland are the most spec-
tacular. They all confirm the same idea: that a great diversity of
life was already present in the Cambrian period. Some of these
animals had hard exoskeletons or shells, others did not. Some
were familiar, others strange and puzzling. There were assuredly
more arthropods than anything else - nobody could mistake those
jointed legs. But what an extraordinary bounty of articulated
phantasmagoria were propped upon those typically spindly legs!
I cannot here elaborate on all the other odd animals in these
faunas: I will only reiterate that, like the devils that persecuted

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TRILOBITE

Christ's madman, they were legion. Gould even famously, and
erroneously, argued that there was more 'diversity' (or, not to
misrepresent him, what he termed 'disparity') in the Cambrian
than was seen ever again in the subsequent history of life.

The curtains had been drawn on a vital drama, and up on
stage there was an elaborate cast, all dressed up to the nines in
both familiar and unfamiliar garb. It was a coup de theatre that
could not have been bettered by Peter Brook. Dazzled by the
brilliant array of costumes the onlooker is confused and overawed
by the sudden burst of spangles and tulle. Surely this is the
ultimate show, a more heterogeneous parade than could have
been dreamed by a zoomorphic imagination in the grip of halluci-
nogens (why, one animal is even called Hallucigenial). This was
a show without precedent, for, like all shows, the cast had no
history, their stage presence was a portrayal of the moment; a
sudden, glorious, opening night. There was an explosion of
characters after a dearth of drama.

Where the theatrical analogy fails is that, unlike a stage play,
the history of life does demand a before and after, a beginning
and (in some cases) an end. We can be stage struck for only so
long, before we try to peel off the make-up, and strip away our
initial astonishment to determine the substance of the characters.
Life has a biography that is rooted back in time, because all
animals are ultimately descended from a common ancestral
species, an evolutionary Adam. This accounts for the shared gen-
etic legacy of all creatures, be they ever so great or ever so small.

The sudden appearance of fossils of so many kinds at this
geological moment has become well-known as the Cambrian evol-
utionary 'explosion'. The dramatic metaphor is no coincidence.
It embodies the idea of a chain reaction somewhat out of control:
that is, a hugely elevated rate of evolution. And, as in all
explosions, the bomb is small but the effects are disproportionate.
But this is a creative explosion, rather than a destructive one, so
that when the curtains of the fossil record are drawn back sud-
denly the whole bang-shoot is revealed in the spotlights after

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the chaos of creative 'explosiveness'. And why the necessity for
explosiveness at all? This is because virtually the only fossils found
below the Cambrian in the late Precambrian, or Vendian, strata
are either simple plants and bacteria, or else soft-bodied oddities
- known as the Ediacara fauna - which are difficult to interpret
as any kind of ancestors of what was to follow. The earlier stage
was strangely lacking any characters that we could recognize. It
is as if the players in the Cambrian drama had appeared from
somewhere else, having dressed and made up in secret. Where
are the late Precambrian brachiopods, molluscs, echinoderms and
arthropods that might have provided the Prologue?

I must confess to a certain diffidence in writing about the
Cambrian 'explosion' question. It has excited so much passion
and disgreement among its several interpreters, some of it remark-
ably ill-tempered, that I doubt whether it is wise to walk into
this volatile environment without a safety helmet. I recall the
words of Charles Darwin in his Autobiography: T rejoice that I
have avoided controversies, and this I owe to Charles Lyell,* who
. . . strongly advised me never to get entangled in a controversy,
as it rarely did any good and caused a miserable loss of time and
temper.' However, the trilobites demand it. It might seem strange
to the reader that events which happened more than 500 million
years ago are still capable of causing the secretion of abundant
venom in living organisms. It is undeniable that some of the most
obvious 'explosions' are to be heard from the proponents of one
theory or another. The puzzle of the sudden appearance of shells
at the base of the Cambrian has been with us for a long time.
Darwin certainly recognized it; in Chapter 9 of On the Origin of
Species (1859) he had despaired that 'the case at present must
remain inexplicable . . .' One hundred and forty years later there is
no shortage of explanations: there is just a shortage of agreement. I
am compelled to join the fray because, of course, trilobites were
among the observers of the explosion - if indeed there was one

* Sir Charles Lyell, whose Principles of Geology was a profound influence on the
young Darwin.

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TRILOBITE

- and were hardy survivors from the Cambrian into the Ordovi-
cian and beyond, outlasting many of those animals, termed Cam-
brian evolutionary 'experiments', which perished without benefit
of descendants. Because trilobites appeared alongside the first
arthropods in the Cambrian they must be part and parcel of the
'explosion' - caught in the crossfire at the very least.

One of the Burgess Shale fossils is a trilobite called Olenoides.
It is another of those rare species in which the limbs can be
clearly observed: the peculiar preservation in the Burgess Shale
allows us to see shiny impressions of legs and gills, and even guts.
Like Triarthrus, Olenoides (fig. 7) has been examined by most of
the leading trilobite specialists from the time of its discoverer,
Charles Doolittle Walcott. It will come as no surprise by now
that the definitive description of the animal was made by Harry
Whittington in the 1980s. In its essentials, the trilobite had a
similar arrangement of limbs to that I have already described for
other species. On the cephalon there were three pairs of limbs
and flexible antennae; each thoracic segment also had the usual
biramous limbs. One difference from the usual pattern was that
Olenoides also had a pair of special antenna-like appendages at
its rear end, known as caudal furca. But the basic trilobite design
was confirmed yet again. Harry noticed that the bases of the
walking legs were truly massive and equipped with sharp spines
which faced inwards towards the centre line of the animal. He
interpreted this spiny corridor as an area where prey items were
shredded and passed forwards to the mouth at the back of the
hypostome: Olenoides was a predator well able to gobble up a
variety of 'worms' - which also abound in the Burgess Shale.
Predator and prey made their debut together.

Trilobites were one of the many animals which were so dra-
matically exposed when the curtain was lifted on the Cambrian
Burgess blockbuster. But for many years before the discovery of
the Burgess Shale by Walcott in 1909, trilobites were almost the
only arthropods known from the Cambrian strata, preferentially
preserved as they were by virtue of their calcite exoskeleton. They

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EXPLODING TRILOBITES

Olenellus, one of the earliest trilobites from the Lower Cambrian strata: already
a specialised creature.

had come to be a surrogate for all that was primitive among
joint-legged animals. It was accepted on the nod that trilobites
could stand in for an arthropod ancestor. Even early observers
could clearly understand that they were quite complex animals,
eyes and all. How then to account for their sudden appearance?
Charles Darwin was unusually confident in the Origin of Species:
'I cannot doubt that all the {Cambrian} trilobites have descended
from some one crustacean which must have lived long before
the {Cambrian}'* he wrote, thirteen years before Thomas Hardy
conft-onted his hero with another such 'primitive crustacean'.

* The original text reads 'Silurian' where I have written {Cambrian!. At the time
Darwin wrote the distinction between Cambrian and Silurian strata had not yet
been recognized (see Chapter 2).

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trilobite!

The attribution of trilobites to the arthropods may be almost
instinctive. The anthropologist Kenneth Oakley made known a
perforated specimen, a pendant probably, recovered from the
Grotte du Trilobite in Yonne (France). This is a late Palaeolithic
cave, and records the first interaction between mankind and trilo-
bite. In the same cave there was found a beautiful carving of a
beetle. 'It does seem reasonable,' says Oakley in 1965, 'to infer
that the trUobite would have appeared to the untutored yet
observant and thoughtful Magdalenian as a kind of insect in
stone.' Quite so. The Magdalenian saw an insect, Darwin a crus-
tacean, Walcott (eventually) an arachnid, that is, a relative of the
spiders and scorpions - they cannot all be right.

But an objective answer to the simple question: what is the
trilobite's closest relative? has proved rather elusive, and is, like
it or not, intimately bound up with the question of the Cambrian
evolutionary 'explosion'. In the first place, the wealth of different
arthropods now known to be present in the Cambrian robbed
the trilobites of their right to claim exclusive primitiveness. Any
one of these other animals might have a prior claim. Several of
them also had the kind of branched limbs with which we are
now familiar. 'Tracks' scraped by such limbs are familiar as fossils,
even predating the appearance of the body fossils themselves by
a short time. It had been assumed that these tracks - which carry
the names Rusophycus and Cruziana - were made by trilobites,
but that was when trilobites were the only known possible culprits.
Now there were many other possibilities. So the discovery of the
Burgess Shale and other, even earlier Cambrian fossil soft-bodied
faunas made everything more complicated.

Notwithstanding, I shall try a simple explanation.

When Harry Whittington and his research students Derek
Briggs and Simon Conway Morris (now famous professors in
their own right) minutely studied the Burgess Shale animals in
the 1970s and 80s they tended to emphasize the peculiarities of the
fossils they studied. They were, after all, describing the costumes
of spectacular performers for the first time in detail since Walcott

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had pulled back the stage curtains.* The distinctiveness of the
limbs of some species, carapaces of others, uninterpretable fea-
tures of yet others seemed to support a notion then current
that arthropods (and by extension other kinds of animals) had
appeared from more than one ancestor. This is correctly described
as 'polyphyletic' origin.

At the height of the popularity of 'explosivism' polyphyly was
rife. Harry Whittington once believed that the various kinds of
Burgess arthropods arose separately from different soft-bodied
ancestors in the Precambrian. At its extreme, this view had it that
some of the Cambrian animals were so different in design that they
merited being placed in the highest category of animal classification
- a phylum. They were not molluscs or arthropods, or whatever,
at all, but merited a separate phylum of their own, or so it was
alleged. Simon Conway Morris is famously quoted as opening a
drawer, encountering a new fossil animal, and exclaiming, 'Oh
fuck, not another new phylum!'. He has probably had cause to
rue these words. At a more modest level, awkward arthropods that
showed peculiar characteristics were regarded as representatives
of 'failed designs'. There was no shortage of these curiosities:
arthropods with giant frontal appendages, or great feathery
antennae, or huge numbers of segments. All were supposed to
have appeared as a result of a special burst of evolutionary creativ-
ity at, or just before the base of the Cambrian, 545 million years
ago. This was the 'explosion'. The dramatic appearance of a pleth-
ora of life on the geological stage was considered a true measure
of evolutionary history. Trilobites were just one of many designs
thrown up at the same time, but they were undoubtedly part of
it, and must have observed their idiosyncratic spindly or bristly
neighbours through their unique crystal eyes. No other Cambrian
'experiment' mastered that particular optical trick.

* I should mention that a number of previous professors have had their turn at
the Burgess animals. The arthropod studies of Percy E. Raymond of Harvard Univer-
sity in the 1920s and Leif Stormer of Oslo in the 1940s contributed much of interest
to the story of their interpretation, notably the recognition of the 'trilobite-like'
limbs of these animals.

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trilobite!

When S. J. Gould explained an early version of the explosion
theory in Wonderful Life, he described the various animals and
laid out the conclusions he drew from them. He attributed, with
some generosity, much of the novelty of the interpretation of
Cambrian events to Simon Conway Morris; 'as for so much of
this book, I owe this example to the suggestion and previous
probing of Simon Conway Morris' (p. 293) was a typical endorse-
ment. The redescription of the Burgess Shale fossils was a team
effort overseen by Harry Whittington. Different beasts were
studied by Conway Morris, Derek Briggs, David Bruton and Chris
Hughes. I had recently gained my first employment as a trilobite
specialist when the 'Burgess boys' were ensconced in their offices
in the Sedgwick Museum, Cambridge, where they spent all day,
every day, feverishly preparing and photographing and discussing
their marvellous animals. I was a fascinated bystander who partici-
pated in the conversations and speculations as they happened. I
pored with Derek Briggs over fossils of the arthropods Sanctacaris
or Canadaspis on their quotidian wooden trays, containing slabs
of black shale which looked so ordinary yet carried on their
surfaces such extraordinary objects. From the outset, I was inter-
ested in how the newly interpreted animals would cast light on
the affinities of trilobites. Curiously, I do not remember hearing
the word 'explosion' once in those early days.

As with most new and attractive theories, it was not long before
all manner of other sources of evidence were recruited in support
or explanation of rapid evolutionary turnover at a critical time.
We met Hox genes in the last chapter: those genes which control
aspects of the sequence of development in all animals. Arthropods
are typically composed of 'packages' of segments - the reader
will by now be familiar with the trilobite's own arrangement of
cephalon, thorax and pygidium. But these packages are differently
arranged in the various major kinds of arthropods: the head may
contain different numbers of segments, as may the thorax. They
are like trains buckled together with different arrangements of
carriages and cars. One theory suggested that the Cambrian

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'explosion' might record a critical period in the expression of
Hox genes, which at that time, uniquely, were 'switching on' new
arrangements of batteries of limbs and segments. The Hox genes
functioned like the presiding genius of a biological marshalling
yard, mastering new rolling stock. In the grand democracy of the
early Cambrian a swarm of these creations could survive, and
devil take the hindmost. Some would produce evolutionary prog-
eny, others would fail after a geological moment of improbable
fecundity. Yet another theory invoked a phase of doubling up of
lengths of the genetic code at this creative time, a genetic change
which increased the possibility of innovation and variation in
body designs. It seemed for a while that Darwin's 'inexplicable
case' might be solvable after all. The 'explosion' was a special
moment in time - triggered, possibly, by some environmental
threshold that had been crossed in the Cambrian world - when
the possibilities of life gloriously expanded, and when parts in
the evolutionary play became suddenly multifarious. For a while,
any strange role was permitted. In popular accounts it became
an ancient moment of madness, a magnificent evolutionary Mardi
Gras, when a parade as bizarre as could have been devised by a
surrealist on speed would be permitted for a geological day. 'See
the crystal-eyed monster!' 'Roll up, roll up, for the shiny, tub-
iferous wiggly orphan thing with no relatives!' The freak show
was open for trade.

It seems almost a pity to spoil the show, to strip away the
dressing and reveal the actors beneath. Most of us prefer glamour
to analysis - glamour can be enjoyed with a smile and a cheery
wave, whereas analyis requires thought and intellectual work. But
it is necessary to do this critical work, if only to understand the
place of the trilobites in the Cambrian charivari.

From the first there were a number of scientists who doubted
the account that Steve Gould had presented, however much they
admired the mannner of its delivery. I was one of the doubters
myself, ever since I reviewed Wonderful Life in the magazine
Nature shortly after its publication. At the time I had already

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trilobite!

started an attempt to look at the Burgess animals and their rela-
tives in a different way.

This work was done jointly with Derek Briggs, who was so
familiar with the details of the Burgess arthropods. Instead of
emphasizing their peculiarities, we were looking for the significant
similarities they shared with one another. The technique of analy-
sis we used is called cladistics. Although its details are technical,
the main principle of cladistics is very simple: it is an attempt to
classify organisms on the basis of evolutionarily derived character-
istics. To give an easy example: if a cladistic analysis were made
of a shrew, an elephant and a lizard, the shrew and elephant
would share several characters, such as uterus, mammary glands,
warm-bloodedness and (patchily in the elephant, admittedly)
hair, which would readily identify them as being more closely
related to one another than to the lizard. Both shrews and ele-
phants are mammals: we don't imagine that complicated charac-
ters like mammary glands arose on more than one evolutionary
occasion. On the other hand, that both shrews and lizards eat
insects while elephants digests trees is not an indication of biologi-
cal affinity at all, but an expression of adaptations for earning a
living. Nor does the peculiarity of the elephant, its ineffable trunk,
make it a mammal, or help us to decide whether or not it was
more closely related to the shrew than to the lizard. Cladistics
identifies only the significant advanced characteristics as the basis
of classification, while similarities which are just a reflection of
an earlier, shared history do not figure. The four limbs of lizard,
shrew and elephant reflect the fact that all belong within a greater
group - the tetrapods - with an ancestry stretching back to the
Devonian, and do not contribute to solving the particular prob-
lem in hand.

So Derek and I had the job of enumerating all the characteristics
of the Burgess Shale arthropods which were present on several
animals - features of the legs, or the number of limbs incorpor-
ated into the head, for example. From the distribution of these
characters we wanted to draw a tree diagram of the relationships

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1

EXPLODING TRILOBITES

of the fossils. As in any family tree of the Cholmondely-Smythes
or the House of Windsor, we should be able to see who is most
closely related to whom and how the more distant members of
the family slot in. Except that we were dealing with common
ancestry, rather than pinpointing Uncle Ernest as an actual ances-
tor. The more animals you study, the disproportionately more
possible ways of arranging them into trees there are; so you soon
need a computer programme to sort out the best arrangement,
especially if some characters may genuinely have appeared more
than once during evolution. 'Best' is, of course, a charged word
- how do you know what is best? - and cladistics programmes
have various ways of deciding this, but most boil down to a
preference for the simplest tree. In the late 80s most scientists
interested in this technique were using a programme called PAUP
(a simple acronym for the intimidating Phylogenetic Analysis
Using Parsimony) developed by an American from Illinois, David
Swofford. In evolutionary circles Swofford's name is about as well
known as Hawking's in astrophysics.

We were stripping these Cambrian arthropods - including the
trilobite Olenoides - down to their essentials to see if they would
'fit' into a tree of descent. If some of the 'oddball' animals could
be accommodated convincingly into the tree, then it would mean
that their distinctiveness might have been over-emphasized by
the explosionists. They might have been too easily dazzled by
their spectacular motley, to the extent that they failed to see that
underneath they shared a common dress.

What surprised us was how easily we could produce a tree
relating nearly all of the Burgess Shale arthropods. This was the
first time that such an objective tree of descent had been pro-
duced, and one of the most interesting things to us was that the
trilobites were quite high up within it. So much for their tra-
ditional role as the archetypal primitive arthropod! If they had
been primitive then they would have been somewhere near the
base. Suddenly the distinctiveness of the crystal eyes seemed to
make more sense. Then the idea that the different arthropods

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trilobite!

arose independently was knocked severely by the fact that a per-
fectly reasonable tree of descent could be reconstructed, with aU
the arthropods having descended, ultimately, from a common
ancestor. Some of the strange arthropods from the Burgess Shale
were truly no stranger than trilobites - it is just that we have had
a hundred years or more to get used to trilobites. Familiarity
breeds, well, familiarity. If there was an 'explosion' then it was a
remarkably orderly one. In detail there were many problems with
our aboriginal tree, which was very much a first attempt - and
crude, as such attempts always are. But in the ten years that
followed other people have tried their own versions, including
our own friend Matthew Wills, and many of the original features
have been preserved. In other words, our tree must have had a
germ of truth.

Derek and I thought we would publish this tree as a paper in
the journal Nature, but Nature had other ideas. The reader should
know that publication in a scientific journal is no simple process.
You must submit the manuscript to the journal, obeying to the
letter all caveats about format and length. Then the journal will
send the paper out to referees, and if it is Nature you will probably
have the pickiest referees in the business. In the majority of
cases they will recommend 'rejection'. Only geniuses like Richard
Feynman or Stephen Hawking routinely get a 'yes' - everyone
else endures some degree of pain. No first-time novelist suffers
more when the terse note comes back, saying 'The editors
regret . . .' So you can imagine our level of disgruntlement when
the paper describing the Burgess tree was given the bum's rush
by Nature. We licked our wounds and resubmitted our paper to
the North American equivalent of Nature - Science (New York)'
- which is about the only scientific journal with an equal repu-
tation. To our relief, after a month or two's agony, the little paper
was accepted and was published in 1989.

Since then a great deal more has been learned about the fossil
faunas that preceded the Burgess Shale in even earlier Cambrian
time. It has been made abundantly clear that many of the arthro-

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EXPLODING TRILOBITES

pods that were described from the Burgess Shale now have rela-
tives in older Cambrian strata. From China, the Chengjiang fauna
has yielded many beautiful animals. The story of their description
makes the Burgess Shale controversies seem almost decorous.
Rival teams of collectors have been racing to be first. Peasants
have been paid to come up with the goodies, even whisking fossils
out from under the noses of their competitors. There have been
rival publications. Cloak and dagger has been followed by back-
stabbing. Chen Jun-yuan and his team of westerners have tried
(with some success) to race ahead of Dr Hou and his alternative
team of westerners. Sometimes, you don't know which name you
should use for a given fossil, Chen's or Hou's. Greg Edgecombe,
an incorrigibly amiable naturalized AustraHan, who has done
much to make these animals known to the world, whistles through
his teeth when I mention future Chengjiang visits to him. 'Never
again!' he says. 'Not f****ing likely!' There is something about
these ancient fossils that excites four-letter words.

Science, of course, does not give a fig for these examples of
internecine warfare. The truth will out, and it matters not if it is
at the cost of bruised egos or skulduggery. Some time in the next
decade or two all the vested interests that have fought over
Chinese fossils will seem as tragi-comic as the nineteenth-century
battles between Professors Marsh and Cope to name the greatest
numbers of dinosaurs in America. As far as the 'explosion' is
concerned, the continuation of evolutionary lines back into strata
earlier than the Burgess Shale simply increases what Gould later
called the 'intrigue and mystery' of events at the base of the
Cambrian. If you add to the brew the Briggs/Fortey tree (or one
of its better subsequent versions) there is a very simple question
to be asked. If the different kinds of arthropods extend to the
early Cambrian (including trilobites, which are near the top of
the tree), then must it not be the case that the only time for
the still earlier branches on the tree to have split is within the
Precambrian? And since these arthropod branches will connect
in their turn with still more and deeper branches in the branching

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trilobite!

history of the whole of animal life, this takes us somewhere still
older and more profound again. You cannot have a great-
grandson without a great-grandfather. We have already met this
argument with regard to the history of eyes in the last chapter.
Eyes are deeply implicated in the history of life. The eyes of
trilobites are tied by a genetic bond to other eyes in other animals,
all the way back to the first simple eye-spots. The estimates of
divergence between major animal groups based on molecular
clocks (which have faults, admittedly) is somewhere between
about 1000 Ma and 650 Ma, but both are substantially before the
Cambrian at 545 Ma. Maybe that dazzHng opening scene of animal
life blinded us to a modest, and much longer earlier drama after
aU.

Some years ago I made a straightforward observation about
the very earliest trilobites. When they first appear in the Cambrian
strata, they are already different in various parts of the world:
not just different species but different genera - even families. If
you go to China you will find specimens of a compact little
trilobite called Eoredlichia - but not Olenellus. If you go to New
York State you will find Olenellus and its friends - but no close
relatives of Eoredlichia. If you go to Siberia along the Lena River
in the mosquito-ridden summer you will see the best exposed
Cambrian in the world, but the first trilobite you find will be yet
another one, Bergeroniellus. Since all trilobites probably descended
from a single ancestor it seems obvious that we must be missing
a phase of their fossil record - the time required to evolve their
different forms in different areas. It all points to some consider-
able history missing from these particular rock sections at the
base of the Cambrian. This is proved beyond doubt in those
beautiful Lena sections where you can see the effects of erosion
before the appearance of the Cambrian fossils. Is this erosional
phase the time for the trilobite to be 'descended from some one
crustacean . . . before the beginning of the Cambrian' described
by Charles Darwin?

One thing of which we may be sure is that the trilobites were

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not descended from any sort of crustacean - trilobites and the
arachnid horseshoe crab Limulus (p. 151) shared a common
ancestor, which in its turn shared a common ancestor with the
crustaceans. Trilobites were distant cousins, not progeny of the
crustaceans. But it is also true that many of the fossils that fit in
low on the tree of descent of the arthropods shared features that
once upon a time would have been thought of as typically trilo-
bite. Those limbs with two branches that C. D. Walcott laboured
so hard to reveal turn out to be very common among all manner
of Cambrian soft-bodied arthropods, too. Arthropods leading to
crustaceans probably had them - as did those that would lead
on to Limulus and scorpions. In a word, biramous limbs are
primitive. Any one of these animals could have scraped simple
trails like the ones found in the earliest Cambrian of all in eastern
Newfoundland. Some other facts are also becoming clearer. The
closest relatives of the typical arthropods are some little animals
with stumpy legs known as velvet worms (Onychophora). They
still live today - mostly under rotting logs in warm, damp cli-
mates. In the Cambrian they were much more numerous and
varied, but also submarine. Graham Budd has shown how a
number of really weird-looking creatures are velvet worms at
heart. So is the once nonpareil oddball from the Burgess Shale,
Hallucigenia. It is a measure of how misleading Gould's theory
would have been if taken at face value: these animals which were
once touted as designs of uncommon originality would have been
simply labelled 'failed experiments' and there's an end to it. As
it now is, they have been recognized as important steps in our
understanding of the subsequent history of life. The lesson of
cladistics is that it is what animals share that it is important in
identifying their relatives, not our subjective judgements about
oddity. We must focus on the elephantine womb, not the trunk,
if we want to place the pachyderm in the scenario of Nature.

So now we are left with a paradox. There is a tree of descent
which helps us understand the history of our characters before their
spectacular appearance on stage - but of this earlier history there

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TRILOBITE!

Anomalocaris, at first claimed as a 'weird wonder', but now known to be related
to primitive arthropods and hence to trilobites.

is no evidence. Even the traces left by animals, their scratches and
burrows, are rare before the latest Precambrian.* Where can the
animals be? Either all the rates of origination must be speeded up
beyond comprehension in the 'explosion' - and out of this
'explosion' a variety of trilobites must crawl alongside everything
else - or there must be some other explanation. Like T. S. Eliot's
Mystery Cat:

But when you reach the scene of crime McCavity's not
there!

The explanation of missing time might apply to some rock sec-
tions, like the Siberian ones, but it does not work for eastern
Newfoundland where the rocks record a complete narrative. My

* As this is written there are new reports from India of much older tracks and
trails, in rocks up to a billion years old or more. There is little doubt that these
markings were made by animals, and indeed it is a scandal that previous reports
by Indian geologists and published in Indian journals have hitherto been ignored.
There is however some reason to question the accuracy of the dating, and for the
moment final judgement must be suspended.

132

EXPLODING TRILOBITES

favoured theory is that the earHer branches in the tree were tiny
animals, which were not easily preserved as fossils. It is not neces-
sary to be large to be a perfectly good arthropod (or mollusc,
come to that). The sea swarms with tiny arthropods today that
have left no fossil record. I like to quote the tiny copepods, which
are members of the plankton so numerous that they can turn the
seas black. Yet their only fossil is a single example of a species
preserved in the body of a fossil fish. Were it not for their miracu-
lous preservation in amber our knowledge of past insects would
be dreadfully inadequate (as it is, we know from amber hundreds
of the most delicate of all, mycetophyllids, the fungus gnats, so
delicate in life that a puff of wind destroys them). What happened
at the base of the Cambrian was probably as much an increase
in size as a sudden appearance of new types of animals. This may
well have been a genuinely rapid change. We know from many
fossils that increase in size is quite an easy goal in evolutionary
terms. Mammals, for example, seem to have undergone a very
rapid increase in size after the demise of the dinosaurs 65 million
years ago. It even seems possible that the same size increase
allowed the possibility for the secretion of shells. Muscle support
becomes much more crucial when an animal reaches a certain
critical size. So the 'explosion' was a dramatic appearance of
characters that had been rehearsing out of sight for more than a
hundred million years.

The explanation just given holds out the possibility of dis-
covery. Maybe one the readers of this page will discover the
Precambrian equivalent of amber. Very recently, a late Precam-
brian animal embryo was discovered in China, amazingly pre-
served cell by cell in the mineral calcium phosphate; age by itself
is evidently no proof against miracles. It would be wonderful to
amaze the world with proof of the missing stages of evolution,
tiny animals that set the designs for the future of life. Somewhere,
there should be a small trilobite, an animal with the potential for
spinning an almost endless variety of costumes for three hundred
milHon years. The search continues.

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trilobite!

This is not quite the end of explosions.

There have been several more accounts of the Burgess Shale
and the Cambrian since Wonderful Life. Most of the arguments
about the truth or otherwise of the 'explosion' of phyla have
been in the pages of scientific journals, in which a convention of
decorousness is observed. Toujours la politessel Steve Gould knew
that I did not agree with his conclusions, but this made no
difference to the cordiality with which we could meet: we could
wave across a conference room without any gritting of teeth. I
do not suppose he was tempted to take a small model of me and
stick pins in it, any more than I was tempted to steal some of
his personal effects and cast a hex. Scientists seldom do things
like that: what they are chiefly interested in is the advancement of
truth. Richard Dawkins tells a good story about a senior professor
coming on stage to shake the hand of the young scientist who
has just disproved the old man's most cherished theory: the older
man earns a standing ovation. Well, that is how it is supposed
to be, according to the etiquette books.

The Smithsonian in Washington DC mounted a Burgess Shale
exhibition, where the public can see the extraordinary beasts for
themselves: the accompanying literature is unobjectionable, and
factual enough. At about the same time as this exhibition was
being opened, the extreme of 'explosiveness' emerged in a book
by the two McMenamins, Mark and Dianna - professors in a
small East Coast university - called The Emergence of Animals.
(1991). In this work they claimed up to a hundred* animal phyla
'exploding' into life in the Cambrian; most of them are also
claimed to have died out, leaving no progeny. They popped up
like so many jack-in-the-boxes, and then auto-destructed, in the
manner of some post-Dada extravagance designed to outrage.
This view out-Goulded Gould ten-fold. The extraordinary thing

* Most modern textbooks list about thirty phyla in the living fauna, which embraces
all the extraordinary diversity of organisms. Each phylum represents a fundamentally
different design in anatomical organization. Thus the McMenamins identify at least
a three-fold richer world in the Cambrian.

134

EXPLODING TRILOBITES

Late Precambrian

Early Cambrian

Ediacaran Soft-bodied Fauna

Low-diversity
Shelly Fauna

Moderate-diversity
Shelly Fauna

High-diversity
Shelly Fauna

<^ Sinot

<^ Trilobites

\^ LapwoTthella

<C Archaeocyathans

'C' Brachiopods

<

Anabarites

1 1

<

Protohertzina

ubt

\_ Deep Vertical Burrows

1

<

Arthropod Traces

ilites >

<^ Cloudina

\

Ediacaran Fauna

\

545 million years before present

The place of trilobites in the emergence of animals in the early Cambrian,
after McMenamin & McMenamin 1989 The emergence of animals. But where
are the ancestors of the trilobites?

to an objective reader is that there is no attempt to justify w^hy these
hundred or so 'Cambrian phyla' should be recognized as one of the
great divisions of the animal kingdom - hov^, exactly, do they differ
from each other so much that they 'deserve' to be called a phylum?
Not a word. Howr do so many of these separately evolved creatures
share curious similarities unless they were descended from a
common ancestor? And if they were so descended - then surely
they belong to the same phylum? Not a scintilla of discussion. One
is driven to the conclusion that these particular writers regard it as
only necessary to appear on the Cambrian stage dressed in any sort
of odd costume to be called a phylum. The time of the performance
alone is a guarantee of novelty.

Nearly ten years after Wonderful Life appeared another book
made an even more explosive sally into this arena. This time it
was written by the star of the original Cambridge enfants terribles
- and the hero of Gould's Cambrian Weltanschauung - Simon

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trilobite!

Conway Morris. In the ten years or so since Steve Gould tran-
scribed the significance of the Burgess Shale for the world (at
least, his view of what was then understood in Cambridge), Simon
had had plenty of opportunity for second thoughts. His revised
view now is apparently like that I sketched earlier: a rather defused
'explosion'. Simon accepted both the need for an earlier history of
animals, and rightly pointed out the ways in which the Cambrian
remained a distinctive period, when shells appeared, genuinely
rapidly, alongside good fossil faunas of animals that lacked them.
There was nothing very incendiary here. I would say that Simon
had come around to seeing the Cambrian faunas in their context
at a crucial phase in the genealogy of life. The explosions were
reserved instead for Stephen J. Gould. I have never encountered
such spleen in a book by a professional; I was taken aback. Gould
doesn't write, says the author, he produces 'perorations'. He lacks
originality, while laying claim to it. This little passage from The
Crucible of Creation (1998) will give something of the flavour:
'Again and again Gould has been seen to charge into battle . . .
strangely immune to seemingly lethal lunges . . . Gould announces
to awestruck onlookers that our present understanding of evol-
utionary processes is dangerously deficient . . . We look beyond
the exponent of doom and there standing in the sunlight is the
edifice of evolutionary theory, little changed.' This is a rather
gassy way of saying that Gould is a mountebank.

It is one of humankind's less attractive foibles that success
breeds envy, and since there is probably no one in biological
science to rival Steve Gould in worldly and critical success - at
least among the literati - it is not surprising that some of his
rivals for the spotlight focus their attention upon him. It is, of-
course, perfectly legitimate to have differences of scientific
opinion, - in fact, it is an essential ingredient of progress. But
what surprised me here was the unwonted explosiveness, the
bilious ballistics. The detail of the attempt to cast Gould in a
poor light extended into the depths of footnotes. Gould (and
R. C. Lewontin) wrote a famous paper in 1979 with the rather

136

EXPLODING TRILOBITES

overblown title 'The spandrels of San Marco and the Panglossian
paradigm: a critique of the adaptationist programme'. But it
addressed an important point about whether all structures found
in Nature had to have a purpose. In one of his virulent footnotes
Simon Conway Morris takes Gould to task for architectural
inaccuracy - apparently the structures in San Marco should not
be called 'spandrels' at all! Tsk, tsk - as if such a terminological
pinprick could puncture all the inflations of the paper. Such
hypercritical zeal has to well up from a deep source. Why should
Simon wish to bite the hand that once fed him? If you look at
those little silvery fossils in their neat trays it is hard to believe
that they can be the origin of such dispute; nor should trilobites
and their allies take responsibility for any verbal bombardments.
Conway Morris and Gould subsequently slugged it out in the
pages of the magazine Natural History. I do not subscribe to the
cynic's view that such disputes are part of the 'hype' to increase
book sales - such antipathy cannot be faked. I was reminded of
a ballad by Bret Harte (The Society upon the Stanislaus), describ-
ing a nineteenth-century fracas in a scientific society over - what
else? - fossil bones:

Now, I hold it is not decent for a scientific gent
To say another is an ass - at least, to all intent;
Nor should the individual who happens to be meant
Reply by heaving rocks at him to any great extent . . .

In less time than I write it, every member did engage

In a warfare with the remnants of a palaeozoic age;

And the way they heaved those fossils in their anger was a
sin.

Till the skull of an old mammoth caved the head of Thomp-
son in.

I could only diagnose the cause of Simon's ire as being the very
praise that Gould once heaped upon him. To return to Richard
Dawkins's story, this is like the young professor stamping hard

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trilobite!

on the foot of the older professor. Wonderful Life was such a
global success. There, preserved in the aspic of a print that could
never be unprinted, v^as the Conway Morris of 'oh fuck! not
another new phylum!' - the Conway Morris of the early 1980s.
The nineties version disowned the ideas of the earlier one, and
quite right, too: scientists are supposed to move with the times.
But what was lacking was any acknowledgement that the earlier
version had existed at all. It was an extraordinary revision of
history in favour of the present. So the root cause of Simon's
explosion was not envy of Gould, but resentment of the hold he
had on the past. The casual reader of The Crucible of Creation,
unaware of the history, would never gather that the author's views
had once been close to (if not actually shared wdth) Gould's.*
Such a reader would never guess that Simon received the Schuch-
ert Medal of the Paleontological Society of America, a signal
honour, in 1989, and endorsed by Gould. 'History is bunk!' Henry
Ford said in 1919. Such sentiments may not be inappropriate
for an automobile manufacturer, but they do little credit to a
historian.

As for the trilobites, they have witnessed it all, and I shall try
to take the long view through their crystal eyes, indifferent as
they are to the splenetic explosions of mere humans. In the minds
of their devotees they have travelled from being unexplained
mysteries to becoming cousins of crustaceans; they have jour-
neyed briefly towards being a phylum all of their own; now
they have arrived back, where they belong, among the other
arthropods, and closer to Limulus than Darwin believed. They
have had theories about their closest relatives exploded and they
have been caught in explosions. Maybe it is time to pack away '
the dynamite and let the explosion metaphor rest for a while. It's
caused quite enough trouble.

* Some of those, like Richard Dawkins, who have responded positively to Conway
Morris's criticisms of Gould, also seem to have been poorly versed in the history
of the 'explosive' opinions. Opponents of Gould in other arenas, they have used
the book as a stick to beat 'the sage of Cambridge (Mass.)', operating on the
principle: 'my enemy's enemy is my friend'.

138

VI

Museum

When indolent holiday crowds saunter through the galleries past
mounted skeletons of extinct animals, or scan simulacra of dino-
saurs jerkily attempting to persuade the viewer that a hundred
million years can be wished away with latex and mechanical
bones, perhaps one in a dozen of the visitors might notice a
door in the wall behind the monsters. A well-polished mahogany
entrance, it can only be opened with a special key. Once in a
while, a curator will emerge from the door and pause for a second,
as if slightly overwhelmed by the sight of the throng. This is the
door which leads away from the show of exhibition and into
another world: the reality of collections of bones and shells.

I went through that inner door for the first time more than
thirty years ago. When I joined the staff of the Natural History
Museum in London it was known in the trade as 'The BM'. The
British Museum: it was a grand title inherited from grand days.
The natural history collections had long since split off from the
antiquities which stock the shelves in the great building at
Bloomsbury: pharaohs and pharmaceutical phials, long-boat trea-
sures and lorgnettes; and their research departments of Antiqui-
ties, Egyptian, Classical, Oriental or whatever. But the BM we
remained - officially, the British Museum (Natural History). In
Italy, my colleagues still refer to us as Tl Britannico', a wonderfully
absolute description that embodies an essentialist view of the

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trilobite!

nation in its collections. It was, I realized, akin to entering a holy
order, complete with the vow of poverty. But I was a fortunate
man, one of the few whose dreams of employment coincided
exactly with reality. I, who had fallen in love with trilobites at
the age of fourteen, was to be one of the few people in the world
paid to do what I would have done for nothing! I was issued
with The Keys. These were a set of heavy steel keys, of the kind
usually used to lock up prison cells. They were held on a steel
ring, and, so I was told, I had to keep them on my person at all
times. On the keys were etched the words '20 shillings reward if
found', dating from the days when a quid would take you and
your sweetheart out for a fish supper, and the change would pay
the bus home. Almost all doors opened effortlessly under their
charms. There was a full-time locksmith closeted in a room that
Charles Dickens would have recognized, whose job was to ensure
that keys glided into locks with the intimacy of warm handshake.

I was assigned to the Palaeontology Department - to the van-
ished world of extinct life. When I first joined the staff of the
Natural History Museum my office was part of the maze. Tucked
inconspicuously under the great ceremonial Museum entrance,
a Gothick cathedral door decked with motifs from nature, my
office also housed most of the trilobite collections in magnificent
old cabinets - the room exuded the scent of scholarship. There
was even an iron balcony that ran around the midriff of the
room, with more cabinets above. Outside the office, an elephant,
no longer required for display, peered out ft^om under a dust
sheet. In this place the world authority on barnacles, T. H.
Withers, had once worked. So had my predecessor, W. T. (Bill)
Dean, who had also studied trilobites in the same room, before
he had been tempted to a job in Canada. This was fortunate for
me, because jobs at 'The BM' were rare opportunities. A round
hole opened, and a round peg was available to fill it.

When I received my first job description it said 'to pursue
research upon the trilobites' which was rather like saying 'amuse
yourself for money'. To my fellow commuters on the 8.02 fi-om

140

MUSEUM

A tray of trilobites from the huge collection in the Natural History Museum,
London. Their labels recall essential information about where and when col-
lected, and by whom - an archive for civilisation.

Henley-on-Thames, Oxon, it probably still seems like that. As
they prepare to wrestle with takeover bids, draft complex memor-
anda for Civil Service Committees, or design new ways to adver-
tise beefburgers, I still march off to the trilobites. 'What do you
actually doV they ask with genuine and bemused curiosity. Well,
the basic job in a national natural history museum is to do
research on species. Other things flow from it, but an understand-
ing of diversity underpins just about everything else. I am one
of a few researchers privileged to name species (in the somewhat
pompous language of the trade, 'a species new to science'). These
are, if you like, the atoms of all subsequent speculations. This is
not the glamour end of science, where galaxies are playthings and
subatomic particles the stock in trade. This is the biological shop
floor. Let me explain.

141

TRILOBITE

Nobody knows exactly how many living species there are. Some
kinds of animals - birds, for example - are large and showy
enough for new discoveries of unnamed kinds to be rather rare.
But as for beetles, only a fraction of the species that thrive in trees
or under rotten logs have been named: the job of nomenclature is
endless (ask any Beetle Man). For the geological past the problem
is a little different. We can sample only a fragment of everything
that once lived. We depend on the preservation of the fossils in
the rocks, itself a capricious business; we depend on luck in
discovery - the right hammer in the right place at the right
time. Trilobites, it will be recalled, are usually fragmentary, so
we depend most of all on the persistent collector to find all the
bits and pieces. Then we can set about deciding if there is a new
species under the microscope. This is not an easy business.

In the first place: what is a species? Among living animals it is
usually easy enough to discriminate species: closely related species
differ consistently in details which can be readily recognized by
the trained eye. Two common European birds included in the
same family, song thrush and blackbird, are easily distinguished
by their plumage, eggs, songs and behaviour, despite a general
similarity; nor do the even more closely related mistle thrush and
song thrush long confuse a practised bird watcher: the differences
in their songs and habits are discriminants enough. But for fossil
trilobites all we have to go on are shed carapaces. Fortunately,
trilobites are rather like thrushes in one respect - they have
different 'plumages' - their surfaces often carry beautiful and
characteristic details of design and sculpture that are very prob-
ably the reflection of true differences between species. Separate,
but related species often advertise their distinctiveness in just this
way: it is a method of making sure that breeding with the right
mate occurs. It is broadly the same principle that ensures that
rockers bond with other rockers (studded leather jackets), rather
than with, say, followers of the Hare Krishna sect (robes and
shaven heads). Given well preserved material we can recognize a
fossil species as truly distinctive with almost the same confidence

142

MUSEUM

as with a living species. How, then, do we record this reahzation
- turn our recognition of a new species into an official statement?

This is where scientific publication comes into the procedure.
You cannot just get out of bed on a wet Monday morning and
decide to make some new species. A species does not officially
exist until its pubUcation in a scientific journal. The author -
often an authority - proposes the species as new and says exactly
why, with appropriate illustrations. It is a serious business. You
must discriminate the new species from all the others described
within the same genus: in the jargon, you are obliged to 'diagnose'
it. This means that you have to sift through a dozen or more
scientific papers, to compare the specimens in hand with all the
other related species which have ever been named. This can be
a laborious process, not least because the papers in question may
well be published in obscure journals originating from Novosi-
birsk, Norwich or New Delhi. It will be obvious that to have a
good library to hand is a tremendous boon to the specialist. The
reference libraries attached to the great museums complement
the collections as ffiel does a motor. If, by mischance or laziness,
you do not do your literature search thoroughly you could neglect
a publication which actually named your species first: then, sadly,
your name would be doomed to synonymy (which is a taxonom-
ist's way of saying sunk into oblivion) because the oldest name
carries priority. Scientific names are not like the street names
in East European cities that change according to the political
complexion of the day. They are well-nigh permanent. A rose by
any other name will always be Rosa to the botanist.

A new species has to have a new second name - the specific
name. Long years of tradition (shortly to be brought to an end)
have set up rules about the classical form of species name. It has
to be derived from the Greek or Latin root of the appropriate
word, so, for example, a beautiful species could be christened
pulcher, or even pulcherrima if it was very beautiful indeed (from
the Latin). It could not be verypretti, or jolliattractivi (from the
vernacular). Rosa pulcherrima would be quite in order. Rosa pulch-

143

trilobite!

errimus would not, because the endings of the genus and species
are supposed to agree in gender - it is a matter of euphonious
sound, if nothing else. I have always rather liked this adherence
to classical roots, if only because it serves to link me with the
pioneer taxonomists of the eighteenth century, who wrote in
Latin and probably thought in it. This much I share with the
great John Ray and the incomparable Carolus Linnaeus (or Karl
von Linne, to delatinize him). We are all linked through the great
endeavour of classifying the natural world; across more than
two hundred years we share the same passion for ordering our
knowledge. I actually rather relish trawling through heavy old
dictionaries compiled by learned classicists (I have Lewis and
Short's Latin Dictionary in front of me as I write) to look up the
word for, say, 'blushing', or 'warty', to attach it to a species, and
I love to read the quotes from Ovid that justify the usage. This
adherence to a past classical culture is a bond, not bondage.

The next stage is that you are obliged to fix your new scientific
tag on a particular specimen, the fons et origo of the name, which
will carry its imprimatur for ever. This is the type specimen (or
holotype) of the new species. Here the museum acquires its pecu-
liar importance. The type specimens of species are housed there
in perpetuity. The collections are the ultimate reference for the
variety of the natural world, past and present. Alongside the type
specimens are all the other collections made from everywhere
from Antarctica to Ecuador, Tien Shan or Timbuctu, an inventory
of everything alive or dead. In the Natural History Museum the
fossil collections alone occupy an area larger than a football pitch
- and there are four floors of them. Each floor has row upon
row of cabinets, and within each cabinet there may be forty
drawers or so. Fifty specimens or more may reside within a single
drawer: the mind soon reels if it tries to compute the number of
specimens altogether in the collections. If I wish to compare a
trilobite with some arthropod that is still alive I have to go to
the Zoology Department. In the Spirit Building there are thou-
sands upon thousands of jars containing fish or snake, octopus

144

MUSEUM

or lobster, pickled to the life. There are lizards collected by Charles
Darwin. There are worms dredged from the bottom of the deep
sea. Here is the one I wanted: a large relative of the woodlouse
called Serolis which lives on the sea- floor under the Antarctic
icecap. It looks superficially like a trilobite (although it is not a
close relative) and I wanted to check a detail of its thoracic
structure. Passing on, I do not have to be overtly anthropocentric
to see in the turned-down Ups of codfishes a depressed commen-
tary on spending a hundred years in a jar. Colour fades, so that
the ghostly quality of spirit preservation seems to match the
antiquity of the specimens. As you slide the doors back upon this
pallid parade of containers and bottles your voice automatically
loses decibels. You reflect: mortality, this is your sad face; you
defy decay only as a ghastly pickle.

Thus, after a species has been named, other scholars can always
refer to the type specimen itself if they wish to know whether an
example they have in hand is the same, or a different species. A
number, usually written on a little label and glued to the speci-
men, is assigned by the curator, official scribe to biodiversity,
which uniquely identifies that particular individual for reference
(computers have made all this information much more easily
available). The holotype has somewhat declined in importance
since a less essentialist view of species has prevailed; it has been
realized that a population of a type collection is preferable so as
to give some account of variation in nature - after all, no two
animals or plants are exactly alike. This enhances the importance
of the whole collection made along with the type (some of these
specimens are referred to as 'paratypes' - literally, by the side of
the type). In the Spirit Building there are types of species so rare
that one of those pale faces looking out at me from their jars
might be the only specimen known. Perhaps it is no wonder that
it has a gloomy demeanour.

I look forward to the time when images of these type specimens
can be summoned up globally on the World Wide Web. Suppose
a researcher in Sibumasu wonders whether he has the same

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trilobite!

butterfly species as one named a hundred years before by one of
the early western explorers: all he need do is log into the appropri-
ate website on his field computer, and there will be a gallery of
holotypes in living colour for him to compare with the specimen
he has in his hand. All that century-long tending with naphtha
balls, and the curator's dedication to numbers and records will
have been justified in that moment. Only by such definitive refer-
ence can we truly know what lives where, and in what numbers.
I believe it will remain necessary to summon such living, visual
images for a long while yet. DNA 'fingerprints' of species are
becoming increasingly important, but they do not substitute for
the wonderful subtlety of the human eye in judging similarities
and differences. It will continue to be more practical and speedy
(and cheaper) to 'do it by eye'. After all, fine discrimination is
probably the reason why the eye and brain have become so
supremely gifted in our own species.

My part in this endeavour is to be one of the few people
privileged to name new species of trilobites. The routine with
fossils differs little from the procedure with butterflies, although
the holotypes of new species are usually less fragile than lepidop-
terans - I have collected many of them myself, and with a ham-
mer. Some fossil species are rare because they are difficult to
collect, which may not reflect their original rarity in nature. They
may be very spiny, for example, or thin-shelled. Over the years
I have named more than 150 new trilobite species, and it still
gives me a little buzz to know that I have discovered a species
'new to science'. There have been a few genera, too. Only once
have I skirted nomenclatural disaster. I decided to name a pretty
new trilobite after an obscure Phrygian nymph, Oenone, a name
I had trawled from one of my classical sources. It just sounded
rather attractive, suitable for the animal. Fortunately, I discovered
at the last minute that the same name had already been used for
a worm, of all things. This is completely against the rule-book,
which is a tome published in English and French called Rules of
Zoological Nomenclature. I have to say that of all forms of bedtime

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reading, with the possible exception of Kennedy's Latin Primer,
the Rules take the biscuit for being the dullest conceivable. It is
a set of 'thou shalts' and 'thou shah nots' for the naming of
animals. Like annual accounts and railway timetables the Rules
are necessary for the smooth running of the (naming) system,*
but are also a pedant's paradise. One of the most important rules
is not using the same generic name twice. Happily, I was able to
quickly alter my name to Oenonella before it got published, and
this name had never been used before - so Oenonella it became,
and remains to this day.

When you name animals you are not allowed to be insulting
to anyone, but the Rules do permit you to be nice and name
animals after colleagues. Two Czech palaeontologists named a
trilobite Forteyops, and there is a Whittingtonia, and a Walcot-
taspis; thus may the worker be commemorated in the beast. Taxo-
nomic legend has it that somewhere in the animal kingdom there
is a suffix -chisme (from the Greek, and pronounced 'kiss me')
which invites a researcher to add the names of would-be girl-
friends before it - as in Polychisme, Anachisme, etc. I named a
trilobite with a singularly hourglass-shaped glabella monroeae
(after Marilyn), and a friend of mine named a hunchback-looking
fossil quasimodo. These little diversions actually help to make
names more memorable. The Rules do not allow you to name a
species after yourself, but jokes in naming are permitted if they
do not cause affront. It is not flattering to name a new species
pnesi in honour of Jones, if you go on to describe it as 'this
diminutive and undistinctive species is a typical inhabitant of
dungheaps'. Usually, species names just tell you, in Latin or Greek,
something about the animal in question: Agnostus pisiformis (the
pea-like agnostid trilobite), Paradoxides oelandicus (the Para-
doxides from the island of Oland), and so on.

* To remind readers who may not be familiar with taxonomy, the generic name
is the first one, and capitalized, and a given genus may contain a number of species,
characterized individually by the second, specific name, which is not capitalized.
Scientific names are always italicized to distinguish them from the vernacular.

trilobite!

To the name is appended the namer. Thus, an unusually attrac-
tive Ordovician trilobite from Spitsbergen (named after my wife,
naturally), is correctly known as Parapilekia jacquelinae Fortey,
1980. This detail serves the useful purpose of directing subsequent
researchers to the reference where the species was originally
described and named: a paper published by Fortey in 1980. In
the case of species named a century ago, or more, subsequent
accounts of the same species (revisions) may also have been pre-
pared. Many palaeontologists that I have never met face to face
probably know me as an appendix to a name. I hope that they
will be astounded by my youthfulness when we finally get to
meet.

The familiar, if slightly garbled, quote from Romeo and JuUet,
'A rose by any other name would smell as sweet' implies that the
naming of names serves little purpose. This same stricture might
be thought to apply to the kind of science which was famously
labelled 'stamp collecting' by the physicist Ernest Rutherford -
and taxonomy may well have been in his mind. That view could
not be more misguided. Although the dubbing of scientific names
may be fun, these same names can also be deployed for real
intellectual purposes. Critical identification is central to some of
the important questions I shall examine below. How can you talk
about the diversity of life in the past unless the units of measure-
ment (species, genera and the like) are accurately defined by
competent taxonomists? How can you speculate on evolution
unless you know that the species you are examining are likely to
be real entities? How can you cerebrate about the ancient geogra-
phy of life if there are no reliable labels to place on this animal
occurring in this continent and that one on the other? Three
rhetorical questions in a row is about as much of an indulgence
as any book should be allowed, so I shall merely answer my own
challenges with: 'Of course you can't' and get off my soap box.

But I should say, pace Rutherford, that the perfectly amiable
activity of stamp collecting differs ft-om scientific taxonomy. For
any postage stamp, we can look up the date of issue in Stanley

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Gibbons's catalogue, check the colour, check the watermark, and
check the perforation, even check the current valuation - there
is a single, unique, right answer which identifies any stamp. But
all questions in real science are journeys towards the right answer.
It is appropriate to recall Robert Louis Stevenson's aphorism: 'to
travel hopefully is a better thing than to arrive'. Science exists in
a continuous spirit of moving optimism. We can never know for
sure that a trilobite species recognized by my considered and
experienced observations of features of the glabella and pygidium
was actually a real, biological species when it lived hundreds of
milHons of years ago. It often happens that another worker comes
along and disagrees with my species, alleging that it might merely
be a variety (usually of one of his). There is no final arbiter
on such matters. Nor can we ever reconstruct a long-vanished
biological world with certainty, for every reconstruction is only
as good as the scientific inferences that have been made about it,
and these inferences are subject to continuous change. Here are
two examples. First, it is only a few years since we realised that
there were phases of high and low carbon dioxide atmospheres
in the past - producing 'greenhouse' and 'icehouse' worlds,
respectively. These conditions influence almost everything on the
Earth's surface, from sediment type to sunlight - and must affect
living organisms. Second, at one time it was believed that fishes
only began to evolve at the end of the Silurian, but now new
discoveries have shown that there were primitive relatives of fish
alongside trilobites for most of their history; this in turn forces
us to look at the ecology of the Ordovician vvdth new eyes. These
are changes in perception of the past. Even as time's arrow moves
forwards, the past is redesigned in retrospect.

In the nineteenth century, a museum sprang up in almost
every large town of the developed world. This was partly the
consequence of a widespread belief in their improving value, in
both an educational and moral sense. It was often a matter of
civic pride. Whereas in medieval times wealthy wool merchants
endowed churches, their equivalents in the industrial age

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TRILOBITE

endowed museums. In Britain there are museums in Hardy
country, in Dorchester and Lyme Regis; and in Wordsworth
country, the Lake District, as at Keswick; and of course in the
great industrial cities: Manchester, Liverpool, Birmingham and
Leeds. In the United States every major city in the East has a
museum, some of them associated with great philanthropic names
like Peabody (Yale) or Carnegie (Pittsburgh). You can find similar
museums in Australia and central Europe. Many of these
museums have natural history collections, as well as the spoils of
the founder's taste in art. Often, their collections include impor-
tant type specimens. For the researcher, tracing these specimens
can be an adventure, because not every small museum knows
exactly what it has got. My friend Adrian Rushton discovered
some specimens of trilobites from the Keswick Museum described
by J. Postlethwaite in a book on Mines and Minerals of the Lake
District, published in a very limited edition in the i88os. Arcane
information, you might suppose, until you learn that trilobites
are inordinately rare in the Lake District, and that Mr Postle-
thwaite named and found many of them. Then it should be added
that the whole history of the Lake District in its geological youth
hinges on the identity of these rare animals.

The creation of great museums is one of the hallmarks of
civilization. During periods of cultural decline such treasuries of
knowledge are abandoned - witness the virtual loss of great works
of Greek science during the Dark Ages. They were saved because
the caliph al-Mamun ordered the construction of a museum
and library in Baghdad, the Bait al-hikma. House of Wisdom,
completed in 833. This was no dull storehouse - it was a vital
link between classical civilization and the Renaissance. I see the
natural history museums of today as bearing witness to what
mankind will do to his planet and the creatures he shares it with.
Even the most curious items may yet prove their worth. Consider
the collection of dog breeds that Lord Rothschild made, now
stored outside London at Tring in the very model of a nineteenth-
century parade-ground exhibition. Surely this kind of thing is

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passe and redundant? But is it not possible that a future researcher
might want to investigate the history of domestication, and that
the old skins might be the source of molecular information? Every
dog shall have his DNA; and a great museum should never die.

r™

The horseshoe 'crab' Limulus now regarded as the closest Hving relative of the
trilobites. (Photograph courtesy Richard Kolar, Oxford Scientific Films.)

151

VII

A Matter of Life and Death

Trilobites, like all other creatures, evolved. I don't just mean that
they changed through time: that much is obvious. Trilobites like
Olenellus, from the Lov^^er Cambrian, are different from those in
the late Cambrian, and these in turn are distinct from those in
the Ordovician, which differ again from specimens found in the
overlying Silurian and Devonian strata. With even a little expertise
a trilobite lover will be able to cast an eye over a group of fossils
and guess their age, even if they cannot put an exact name to
them. They respond to what bird watchers call the 'jizz', a kind
of overall impression that rarely misleads. Clearly, trilobites
replaced one another through the geological ages. In most rock
sections, though, we assume that every trilobite novelty that
appears was an evolutionary innovation even when the rocks
themselves may often provide no details of its origin. To see
'evolution in action' is rather rare. This rather mundane truth
has been misappropriated by creation 'scientists' as evidence that
'fossils don't provide support for evolution' - which is not the
same thing at all. In fact, the order of appearance of trilobites is
certainly consistent with evolution: Cambrian trilobites have more
primitive characteristics than those in the Ordovician and
younger, as we have already seen in the case of the peculiar,
and evolutionarily advanced, schizochroal eye. It is just that it is
genuinely difficult to catch the appearance of new species in the

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A MATTER OF LIFE AND DEATH

act of creation. In a burglary, it is rare to come upon the scene
with the miscreant standing there, caught red-handed and carry-
ing the swag: the subsequent mayhem is what people usually
come home to. So with the generation of species - the endurance
of the species after the event is relatively long, so that this part
of their history will be more likely to be discovered, just by the
laws of probability, which have no respect for wishful thinking
whether creationist or Darwinian. To maintain the criminological
metaphor: sampling bias alone leaves little chance of conviction.

So examples where you can see evolution at work become
doubly precious. Our own genus. Homo, and its several species
related to modern Person, is not a particularly good subject:
hominids have few fossils and the most arguments. This does not
mean that we are not finding out more and more about hominids
- new fossils turn up every year - it is just that human history
may not be the best choice for studying features of speciation
itself. The fossils are still too rare. By contrast, trilobite examples
have been central to some of the most vigorous debates about
how evolution happened. Since they are complex and abundant
fossils, they might be expected to be particularly useful 'experi-
mental material' to cast light upon how new species are generated.
In the laboratory, another arthropod, the fruit fly Drosophila,
has for many years been used as the experimental animal for
genetics-in-action. The classical studies on inheritance were
carried out upon this little fly. When the roles of specific genes
were investigated - most recently the family of HOX genes that
control sequence in development - it was Drosophila that was
manipulated to produce hopeless but informative monsters with
extra pairs of wings, or legs in place of antennae. FossUs of flies
are too delicate for any but the most exceptional preservation in
amber. Maybe robust trilobites could be the fruit flies of the
rocks.

What is required as a test case is a sequence of species found one
after another, in the same rock succession, which can reasonably
be interpreted as having an ancestor-descendant relationship.

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trilobite!

There should be large numbers of specimens collectable from
many rock layers recording the whole history of both the older
and younger species - so that measurements can be made on
what happens to the shape of the animals throughout the time
of deposition of the rocks, not least to convince the sceptics who
doubt that any evolution is going on at all. Unusual sedimentary
successions are required which lack prolonged breaks in depo-
sition - for hiatuses may disguise the very moment of evolution
into a different species. Most rock sequences are, in practice,
incomplete. It is not altogether surprising that these critical initial
conditions are rarely met: most rock successions fail on one cri-
terion or another. The most suitable deposits - and these are
of comparatively young geological age - are the rocks which
accumulated on deep-sea floors, where a continuous rain of
plankton ticks off time in a settling mist of tiny shells. These little
fossils, often belonging to single-celled, calcite- shelled organisms
called foraminiferans, have provided many of the best evolution-
ary case histories, not least because they are so abundant. A
handful of rock may yield hundreds of specimens. But their small
size also means that they tend to be rather simple - a few bubble-
like chambers a millimetre across. And maybe plankton has evol-
utionary properties different from their bottom-living relatives.
Trilobites might, after all, provide an example which is much
more typical of most marine life. The immediate problem is the
obligation to collect samples large enough for a convincing study.
This means hours of bashing rocks, even if the fossils are quite
common. You cannot study trilobites as you might gas a few
generations of fruit flies to see the changes in the genealogy. The
long-term application of brute force is required to get a decent
sample. There have been several scientists who have this kind of
doggedness, strength and patience. As we shall see, they came to
quite opposite conclusions on what the trilobites had to say about
the origin of new species.

The phrase 'punctuated equilibrium' has become rather
familiar: I recently heard it referred to horribly as 'punk eck' by an

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A MATTER OF LIFE AND DEATH

Australian philosopher of science. Few laymen, or even scientists,
realize that its genesis was thoroughly grounded in trilobites. In
the late 1960s a young American, Niks Eldredge, was studying
the Devonian trilobite genus Phacops in North America. We have
already met Phacops as the possessor of marvellously complex
schizochroal eyes, in which each lens was a tiny calcite spheroid,
separated by a little inter-lensar sclera. The number of lenses is
relatively few, and they are easily countable under a microscope.
It is a very common fossil in the appropriate strata exposed in
the states of New York, Iowa and Oklahoma, and many other
localities besides. It is often well-preserved in limestones, a preser-
vation that permits its most intimate details to be inspected. A
few taps in the right locality, and out a Phacops will pop (usually
the cephalon) as if to say, 'jeepers, creepers! how about my peep-
ers?'. Phacops provides one of those rare cases where there is a
hope of discovering the particulars of the evolutionary process
between one species and the next, so prolific is the fossil record.
To his credit, Niles realized this scientific opportunity quite early
in his studies.

Niles noticed changes in the arrangement of the lenses in the
eyes of Phacops species. He counted the lenses in their 'dorso-
ventral files' - the number of lenses in each row counted from
the top to the bottom of the eyes. Let him describe in his own
words the observations that he confirmed while writing his disser-
tation, as recalled recently in his book The Pattern of Evolution:

Bingo! Another pattern leapt out: Populations in the
Appalachian basin seemed to be invariably 17 dorsoven-
tral files, for almost the entire length of Middle Devonian
time ... In the Midwest the story was altogether differ-
ent: For 2 million years or so, the number remained
stable at 18; thereafter, for at least another 2 million years,
the number was also stable, but it was 17, not 18; for the
very last part of my time frame, the trilobites had 15
dorsoventral files . . . large chunks of time were missing

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TRILOBITE

in the midwestern rock sections precisely when the
changeover from 18 to 17, and from 17 to 15 files occurred.
The seas in which Phacops rana. . . lived simply dried up
during those intervals . . . the change from 18 to 17, and
later from 17 to 15 dorsoventral files in the Midwest
simply marked a repopulating of the seas. The pattern
suggests that the 18 file form became exinct when the
midwestern seas first withdrew; when the seas returned
the 17 file form was available and took over the newly
reconstituted marine habitat.

Niles focused especially on the changes in the eyes because he
saw that here were the crucial characters for defining the species.
If he had been studying birds it might have been tail feathers or
song. If he had been studying molluscs it might have been the
patterns on the shell. Each animal parades its own peculiarities
to establish its own identity. Species flaunt their personalities to
signal to their own kind.

Two conclusions come out of Niles's observations on Devonian
Phacops. The first is that the events portraying generation of new
species are rather hard to observe - they seem always to happen
'somewhere else'. However, subsequent to the appearance of a
new species, the successful innovation often invades, and replaces,
an earlier species. In some cases Niles knew where a new species
originated, but entirely transitional populations between new and
old species were hard to find. This phenomenon may be compared
with the Beatles overtaking the pop music scene in the sixties -
only to be replaced by Bee Gees in the seventies, or Michael
Jackson in the eighties. The early discs are the collector's items,
the later ones characterize a whole cultural phase and are as
common as unsuccessful lottery tickets. Thus, the new species
often starts out as a relatively small population somewhere on
the edge of the range of the (then) dominant species; geographical
separation is what produces a species difference. But when its
time comes the new species replaces the ancestor and enjoys its

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A MATTER OF LIFE AND DEATH

own hours of glory. This is where the Harvard University biologist
Ernst Mayr's influence was crucial, for Mayr had already observed
that in the living world new species often seemed to have been
generated as a result of geographical isolation of a group of indi-
viduals (this process he termed allopatry); disjunct populations
may have acted as the 'motor' for evolutionary change. The iso-
lated group had its gene flow with the mother species interrupted;
and separation alone could breed novelty. Evolution did, really,
happen 'somewhere else'.

Niles's second conclusion was that once a new species had
arrived it endured, often for a long time, with little change. We
may not see the origin of the species, but we do see its acme.
Like the burglar that broke in at the dead of night, the significant
event was clandestine: we see the aftermath, but not the deed.
The mundane demonstration of this in the rocks is the observa-
tion that a particular Phacops species, once it has appeared,
endured for a long time with very little change. To the practical
field geologist this means that much breakage of rock to recover
trilobite fossils by working through metre after metre of strata -
the bloodied fingers, the wet feet, the mosquito bites (especially
in New York) - is rewarded by a cry of 'no change!'. This is hard,
hard labour to show the absence of something, which in some
scientific circles is often called negative evidence; strenuous work
for no result, you might suppose.

Except that the result was highly important. Species, said Niles,
originate allopatrically - 'somewhere else'. When one of these
species successfully invades, and then replaces, its ancestor it
endures for a considerable time. Life proceeds by fits and starts;
a species lasts until it is replaced by another - and that replace-
ment is rapid. Taken together, the two ideas - the endurance of
species, and allopatric speciation - make up the conceptual basis
for punctuated equilibrium; the choice of words for this theory
win by now be obvious. The equilibrium is the enduring phase
of a species' life; the punctuation is its sudden replacement. We
shall all be changed, in the twinkling of an eye, as Corinthians puts

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trilobite!

it. The new theory was set up in opposition to the notion of
'gradualism', a slow and more or less continuous change or shift
that nudged whole populations towards the new species. This
was considered to be the dominant model for evolution in the
aftermath of the 'modern synthesis' of evolution in the 1930s -
and a rather supine acceptance of this creed ensured that the
'punctuated' view, when it appeared, was heralded as startlingly
novel. Niles joined forces with Steve Gould to present the new
model, and with considerable success. Their original 1971 paper
achieved an enormous 'citation index' - this is a measure of the
influence of a piece of published work by the number of times it
is quoted in the bibliography by other workers. The punctuational
description of evolutionary change lent itself readily to metaphor,
and other observers were quick to point out similarities in several
areas of science and culture that were not just concerned with
speciation of animals. Even human history could, with a little
massaging, be described in terms which seemed consistent with
'punk eck': for example, cultural revolution was often followed
by dynasties which finished in a state of stasis. Gibbon's Decline
and Fall of the Roman Empire might exemplify the inevitability
of historical patterns as much as human foibles. In a book that
appeared some years after the seminal paper. Time Frames, Niles
himself went along with the pervasiveness of punctations in his-
tory. The story of our planet's development, it seemed by then,
was a tale told mostly by jerks.

This perceptual revolution was perhaps an inordinate burden
to place upon the cephalon of the humble, if pretty, trilobite
Phacops, whose eyes alone would have been able to see the evol-
utionary truth. As we have already discovered, they probably
saw rather acutely. Other punctuational examples from the fossil
record soon joined the 'ay' voters. Quite soon, the punctuation
explanation provided a rational counter to creationists who
sought to exaggerate the rarity of 'missing links' in the fossil
record to counter evolutionary theory. On the contrary, such gaps
might be just what evolution demanded. As a life-long rationalist

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A MATTER OF LIFE AND DEATH

in defence of the explicable against the numinous, Steve Gould
welcomed this arsenal of ammunition in his campaign to educate
those who denied the magnificent narrative of Earth history in
favour of a week's labour by the Creator. Phacops had become
tied up with some contentious company. Arguments raged
between bible purists and evolutionists: it was a case of trilobite-
by-jury.

Niles was not the first to make the observation of 'punctuated'
change in trilobites. Nearly forty years earlier, a German from the
University of Greifswald, Rudolf Kaufmann, had drawn similar
conclusions from a minute study of late Cambrian olenid trilo-
bites from the Alum shale of Scandinavia. We have already met
olenid trilobites of the genus Triarthrus; this was one of the
trilobites of which the legs and antennae were first known in
detail. It will be recalled that olenids lived in a special environment
in which the sea floor was low in oxygen, while in the sediment
below there was a complete lack of oxygen and a high concen-
tration of sulphur. I even suggested that the olenids may have
cultivated colourless sulphur bacteria as symbionts. About 500
million years ago in the late Cambrian an Olenid Sea spread
across the whole of southern Scandinavia, an inundation that
persisted for something like fifteen million years. This was a
special time, because during much of this long period there was
nearly continuous deposition of dark, shaly strata, which now
yield frequent trilobite fossils. If you can find a quarry exposing
the Alum shales, you break up the smelly nodules known as
'stinkstones' - often about the size of a rugby football - and find
beautiful and abundant trilobite remains. The Alum shale is a
famous example of a 'condensed deposit' where much geological
time is crammed into a thin sequence of strata that accumulated
without major breaks. This approaches the ideal case for carrying
out evolutionary 'experiments' in the field. Kaufmann was astute
enough to recognize this, and made careful collections from suc-
cessive layers of strata to observe the subtlest of changes through
time. Niles did fully acknowledge this pioneering work, published

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trilobite!

Rudolf Kauffman, a portrait of the tragic German trilobite palaeontologist.

in 1933, work which would certainly have been more widely
known had it not been published in a journal of Greifswald
University with very limited circulation. (This recalls Gregor
Mendel's crucial experiments on inheritance in plants carried out
in the Czech town of Brno, and their long struggle into the light
of international science; it might be even worse today, with ten
times more journals competing for attention.)

What Kaufmann observed was that several species ofOlenus (see
p. 65) appeared suddenly in the rock sections, and then had com-
paratively long ranges. But during their 'lifetime' the species were

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A MATTER OF LIFE AND DEATH

not Static; instead they showed small variations, especially in the
shape of the pygidia, which became progressively narrower and
longer through time. The same changes happened to the pygidia
of different Olenus species. Kaufmann clearly showed the invasion
of a species from elsewhere into the Olenid Sea of Scandinavia,
thus presenting a graphic illustration of allopatry before it was a
recognized concept. Furthermore, he based his results on large
collections, and analysed the results in a quantitative fashion.
Euan Clarkson has revisited the famous Swedish quarry at Andra-
rum in the last few years, and repeated Kaufmann's observations.
Clearly, this was a remarkable and far-seeing scientist.

I was puzzled by Rudolf Kaufmann's apparent disappearance
from the trilobite firmament after this seminal paper. Scientists
can usually be mapped through a career of twenty-five years or
more (in some cases you wish it were not quite so long). They
leave behind a legacy of papers, which can be used to track an
intellectual lifetime - literally a paper trail; not least, people tend
to quote themselves, so that you can find out a biography from
a bibliography at the end of a paper. To an experienced researcher
with a good museum library such sleuthing is almost routine.
Not so with Rudolf Kaufmann; he simply vanished. It was not
until 1998 that I discovered why. It is an extraordinary and moving
story.

That we know the story at all is because Reinhard Kaiser bought
a mixed bundle of letters and postcards at a stamp auction in
Frankfurt-am-Main in 1991. He paid 500 Deutschmarks for the
job lot. Among the batch were Rudolf's letters to Ingeborg Mag-
nusson, his Swedish lover. Kaiser was so engaged by the poignancy
of the tale they revealed that he discovered who Rudolf Kaufmann
was, and pieced together the narrative. Sadly, Ingeborg's letters
to Rudolf have not survived. Her devotion is indicated by the
fact that she never married, and kept the letters from Rudolf until
her death in 1972. They had met in 1935 when he went to Bologna,
the ancient university city in north-eastern Italy; he had fallen
instantly in love with the dark-haired Swedish girl. She was only

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trilobite!

united with him again for a few days between their Bologna idyll
and his tragic death. The story is glimpsed in fragments through
their correspondence; it tells of his attempts to reach her Swedish
haven during the ghastly years of Hitler's dictatorship. Kaiser
called his story Konigskinder (king's children) after a comparison
Kaufmann had made in one of his letters to the figures in a
folksong:

Es waren zwei Konigskinder, die hatten einander so lieb.
Sie konnten zusammen nicht kommen, das Wasser war viel zu
tief.

(There were two king's children, they loved each other.
They could not come together because the water was too
deep.)

Rudolf Kaufmann was Jewish by birth, although a practising
Christian. His masterly work on olenids was published just two
days after Hitler became Chancellor, and took over the govern-
ment, on 30 January 1933. Kaufinann was fired from his job at
Greifswald University almost immediately. This did not prevent
him from pursuing his palaeontological studies outside Germany,
but the Bologna visit where he met Inge was to be his last.

Kaufmann was well aware of the importance of his studies on
the trilobites which were his second love. He wrote to Inge that
he would send her everything that he had written as a geologist
because 'it will soon no longer be true that I have done all
this research', a reference to Hitler's denial of the intellectual
achievements of Jewry. 'I am very proud of my great work on
trilobites. I have been able to prove that there is a determined
development in the life history of these animals. I think I will be
much more famous than at present many years from now, when
zoologists and palaeontologists begin fully to understand my
work.' He has not yet had his due.

While separated from his lover, Kaufrnann succumbed to temp-
tation. He was imprisoned in Coburg in 1936 for illegal sexual

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A MATTER OF LIFE AND DEATH

congress with an Aryan woman. In fact, he had visited a prostitute
and caught a venereal infection; it was the doctor who treated
him who subsequently betrayed him to the poHce. On 13 August
1936 he wrote to Inge: 'I wanted to confess everything to you in
Sweden, but now it's too late for that. I am no longer worthy of
you, and I beseech you to try to forget me. I thank you for your
faithful, pure love . . . you were so good to me and I proved
myself to be weak, and now I have to pay for my actions ... So
much has already been taken from me in my life; my mother,
my beloved career . . . This time, however, I have failed out of
foolishness and I must bear your decision.'

Although Inge readily forgave him, his lapse cost him dear. By
the time he got out of prison on 12 October 1939, hostilities had
already commenced. Had he been released six weeks earlier,
before Britain and France declared war on Germany on 3 Sep-
tember, he might well have made good his escape. Several other
trilobite experts fled from Nazism. Alexander Armin Opik was a
member of a distinguished Estonian scientific family (his brother
was a famous astronomer) who escaped to Australia; his fellow
Estonian Valdar Jaanusson became doyen of Scandinavian trilo-
bite experts at the Swedish National Museum. The Baltic Sea was
not the same barrier to them as it was to the 'King's children'.
By November 1939 Kaufmann was in Cologne. 'And when I am
alone?' he wrote. 'I am with my much-loved Trilobites, of which
you can already be jealous. I recently read the Odyssey. I must
learn from Odysseus ... see how he bore his longing for Penelope,
and treat it as though it were written for me.' He remained
optimistic in the face of growing evidence that would have
reduced somebody less buoyant to despair. But, gradually, his
hopes dimmed of ever being united with his lover; by July 1940
he confessed that he 'had no courage for the future'. He doubted
whether he had the strength to continue. 'Yet I cannot lie. The
short time we were together, and the long separation, and the
worries of last month, and of every moment, and the hopelessness
of the future. These are all to blame . . . Try to be free, as free

163

trilobite!

as you can. There is too little hope that we will see each other
for a long time in the foreseeable future. Wouldn't it be better
if we weren't so close, if we did not have to torture ourselves so
much? ... I take you into my arms once again and kiss you with
all my heart.'

By 1941 Rudolf Kaufmann was in exile in Kaunas, Lithuania.
The Baltic Sea was not far away, but it was still too deep and too
wide. He had given up hope of joining Inge. He was shot in cold
blood by two guards who happened to recognize him, and became
just another digit in the most disgraceful statistic of the twentieth
century. The progenitor of punctuation had fallen victim to one
of the most aberrant cultural shifts in human history. Reinhard
Kaiser discovered photographs of Rudolf: with his slicked-back
black hair, handsome regular features, and a rather Germanic
high seriousness, he was the very model of a young Professor,
and you can understand Ingeborg's passion for him.

So it is that the study of trilobite evolution casts light both
upon the fundamentals of how new species are generated, and,
as I discovered through Kaiser's detective work, also upon the
paradoxes of the best and the worst in the human condition. The
enthusiasm Kaufmann felt for his trilobites, and his passion for
the investigation of the truth they revealed, was matched by his
love for Ingeborg Magnusson. Who knows what reputation he
might have forged if he had been permitted to follow both his
heart and his mind?

Punctuated equilibrium was not the only pattern of evolution
that trilobites revealed. During the late 1970s another young man,
an Englishman this time, was studying the trilobites of the area
around the old spa towns of Builth and Llandrindod Wells, part
of the borderland region between England and Wales. This is
hilly country, a patchwork of deep green fields where sheep are the
main crop, interspersed with wooded holts and little steep-sided
valleys where fallen branches thickly covered with feathery mosses
vie with tangled brambles to impede the progress of the geologist

164

A MATTER OF LIFE AND DEATH

in his Wellington boots and thorn-proof jacket. Pheasants sud-
denly start from the undergrowth uttering sharp cries. In the
streams you will meet toads quietly going about their business
among the ferns. There is a sense of moist abundance: so rich is
the vegetation that the overhanging foliage cuts out most of the
light. The best time to do fieldwork is in the spring, before the
stinging nettles have sprouted and hidden the rocks, and before
the generous leaves of chestnuts or hazel have fully unfurled. In
late April there are bluebells on the banks, and drifts of yellow
celandine, and blackbirds everywhere. In the banks of the streams,
encrusted with liverworts, there are heavy, black mudstones, what
the Welsh term 'rab\ which you can pick out in small slabs with
the pointed end of the geological hammer. Split the slabs in the
right direction and you will be rewarded with trilobites. Carefully
work your way upstream to sample successive rock beds, and you
will be party to a narrative that spells out evolutionary changes
through geological time. The rock succession is relatively thick -
many tens of metres - compared with the 'condensed' shales that
Rudolf Kaufmann had sampled in Sweden. This is an advantage:
if you cannot find fossils in a few feet of strata the chances are
that you have not passed a major geological event - in Sweden,
a comparable thickness would be a vital contribution to the narra-
tive of time. The rocks are of Ordovician age, about 470 million
years old.

Peter Sheldon spent years collecting these dark rocks. With
consummate patience, he split the ungrateful shales for month
after month, slowly accumulating and labelling samples of trilo-
bites which he would later analyse. Mostly, he found isolated tails
or heads; occasionally he was rewarded with a whole specimen.
The commonest of the trilobites was an old friend, the asaphid
trilobite Ogygiocarella, which will be recalled as the first ever
trilobite to be described - as a 'flatfish' - by Dr Lhwyd in the
vicinity of the South Wales town of Llandeilo. In these dull
shales there was a trawl of flatfish sufficient to satisfy Neptune
himself. The semicircular, furrowed tails split from the enclosing

165

trilobite!

rab; with a little skill they could be displayed perfectly, little fans
mostly larger than a butterfly's wing. The narrow axis occupies
the central part, and is divided into numerous rings; the flat
pleural fields are divided into an equal number of ribs which get
shorter and rather less distinct towards the posterior of the tail.
Alongside these large trilobites, and slightly less abundant, are
smaller ones no more than a few centimetres long, and more
commonly found in a complete state. These belong to the blind
genus Cnemidopyge (fig. 25), a trilobite with a semicircular head
and with a long spine extending forwards from the front of the
glabella. This animal had only six flat thoracic segments, and a
triangular pygidium which was, like that of Ogygiocarella, strongly
furrowed. Occasionally, it is possible to find one that has rolled
up. There were other trilobites, too, including a close relative of
the 'Dudley Bug' Calymene, and distinctive little medallion-like
trinucleids.

All these animals were collected by the persistent Peter Sheldon.
He got to know the country and the strata with an intimacy
which must surpass even the farmers who own the land. He had
to move ft-om one stream to another to obtain a complete picture
of the succession of rocks by carefully tracing an individual stra-
tum across country. The work was very slow, and made still
slower by the fact that Peter is one of those enthusiasts who love
to explain his work to all comers. He is ft-iendly, sempiternally
youthful and tirelessly optimistic, all of which has served his
dedication as a teacher at the Open University for a number of
years. While he was writing the dissertation for his PhD he was
always returning for 'just one more collection'. In the trilobite
world he became notorious for his reluctance to leave the outcrop
and write up. Normally PhD theses are supposed to take three
years, four at most, but Peter's seemed to go on for ever. He
dodged the censorious glances of the senior faculty, and just
plugged on, splitting more and more black shales and collecting
more and more trilobites. Just when he might have tried the
patience of his supervisor beyond endurance - bingo! (as Niles

166

A MATTER OF LIFE AND DEATH

Eldredge would have put it) he published the result in Nature.
It instantly made him quite famous.

What he claimed was that the trilobites from the Ordovician
strata around Builth Wells showed a kind of gradualistic change
through time. He showed that this kind of change affected not
only one, but several of the different trilobites that ranged through
the black mudstones and shales. The most obvious example from
the largest and commonest trilobite, Ogygiocarella debuchii-,
showed an increase in the number of ribs on the pygidium, from
11 to 14 on average. In the last century the pioneering British
trilobite expert, John Salter, had recognized the form with more
ribs as 'variety angustissima . These are exactly the kind of subtle
changes which trilobitologists use to distinguish fossil species.
What Peter showed was that there was a seamless transition
between debuchii and angustissima. The large populations he
collected showed a good deal of variation at any one level - that
is, there were specimens with various numbers of ribs found
together at any one time. On some examples, there were even
half-ribs on one side of the pygidium, but not the other. In
general, though, there was an unmistakeable trend - at the popu-
lation level - to having more ribs through geological time. When
he collected at a very minute scale he found that there were
even short-lived backward steps in rib number within the overall
increasing trend. The progression from one form to another
resembled the tottering steps of the cartoon drunk rather than a
smooth progression. Even more exciting, Peter found that the
tail of Cnemidopyge was undergoing a parallel series of changes
at the same time through the same strata - Ogygiocarella was not
unique.

There were subtler changes in some of the other trilobites, too.
It all pointed to a very different mechanism for change from that
which had affected Phacops. Even if the shales accumulated at a
rapid pace under the Ordovician sea, each of these changes must
have taken several million years to have proceeded to completion
- this is change of a different order of magnitude from the rapid

167

trilobite!

alterations induced by allopatric separation. It is actually rather
difficult to think of a mechanism that would reset something this
slowly - after all, fruit fly breeding experiments can drive an
advantageous mutation throughout a population within a com-
paratively modest number of generations. Could it be 'drift', with
no particular adaptive function? Other critics suggested that the
changes seen in the pygidia were not evolution at all, but were a
response to slowly changing conditions on the sea-floor. These
kinds of pygidial modification might be a response to changing
oxygen levels, for example. Where gradualistic change had been
observed in other fossil examples it was usually plankton that
displayed it. There was really no question that Ogygiocarella and
its friends were bottom-dwellers, so this example retains its
puzzles and disputes. What nobody questions is the reality of
what Peter observed and its relevance to evolutionary questions,
and who could fail to admire the unusual persistence that inspired
the observations?

There is another test case for evolution where trilobites have
assumed a starring role: as a field demonstration of what is known
as heterochrony. The term is Greek for 'other time', and is simply
explained. Trilobites grew ft-om a larval state starting as little discs
- protaspides - a millimetre or less in length. They then passed
through several moults as they increased in size to achieve the
adult state. The small growth stages first show the demarcation
of the (proto) tail from the head. Then the thoracic segments are
'released' into the thorax, one at a time in most species, and very
probably at successive moults, until they reach the adult number
of segments. Thereafter, in most trilobites, segment number
remains the same even though the trilobite may increase quite
dramatically in size - the mature number of segments in the
thorax may be achieved while the trilobite is still quite small.
Changes to almost all parts of the carapace occur during this
growth, properly called ontogeny. The growth story is known for
a large array of trilobite species, and this makes them especially
important in studying the relationship between the development

168

A MATTER OF LIFE AND DEATH

The smallest trilobite, Acanthopleurella, a diminutive, blind trilobite with four
thoracic segments mature at just over a millimetre in length. Ordovician,
Shropshire, western England.

of the individual (ontogeny) and the appearance of novel features
in new species (phylogeny).

Some years ago Adrian Rushton and I noticed that the tiny
trilobite Acanthopleurella, with only four thoracic segments, was
probably related to Shumardia (p. 222) with six. Acanthopleurella
is even smaller than Shumardia., and we concluded that it was
derived from its ancestor with six segments by a process of
'arrested development' - it became sexually mature when only
four segments had been released. This explained its minute size,
mature at just over a millimetre. It was particularly satisfactory
that we identified Shumardia as an ancestor, since Sir James
Stubblefield had used this very trilobite to prove that the thorax
grew during ontogeny by release of thoracic segments from the
front edge of the pygidium - they were 'budded off there and

169

trilobite!

moved forwards, like customers in a growing queue, as more
were added on behind. We could feel confident that the last two
segments were repressed in Acanthopleurella by comparison with
Shumardia.

At about the same time. Ken McNamara was making more
detailed observations on the Lower Cambrian trilobite Olenellus
from Scotland. Olenellus will be remembered as the most primi-
tive trilobite from our parade, a form with numerous thoracic
segments and a tiny pygidium. Soft, yellowish shales crop out in a
few places in the bleak but beautiful coastal north-west Highlands,
where sphagnum bogs and tussock grassland are populated by a
few highlanders and rather more sheep, both equally hardy. This
is famous ground for geology, because the interpretation of the
Moine Thrust there was the subject of a great Highlands Contro-
versy in the latter half of the nineteenth century. The Cambrian
shales lie underneath the older Moine rocks, which were eventu-
ally proved to have been thrust over on top of the Cambrian.
The trilobites from the shales provided undeniable evidence of
their age. I have spent a very wet and cold summer field season
in the area around the little town of Durness - about as far
north-west as you can go on mainland Britain - snuffling rather
unsuccessfully over the outcrop after fossils. My woollen socks
spent most of the time drying over a meagre butane fire. I was
left with redoubled admiration for the geologists Peach and Home
who had worked out every detail of this uncompromising land-
scape, and most of it on foot. In the century since these heroes
solved the geological map we've become a namby-pamby lot.

Ken McNamara was interested in the trilobites for reasons
other than their antiquity. He had realized that the genesis of
several species of Olenellus could be understood very readily as
an example of heterochrony. He already knew the development
(ontogeny) of the commonest species, Olenellus lapworthi, named
for the great Charles Lapworth, the scientist who in turn had
named the Ordovician. Ken recognized that various other
Olenellus species from Scotland had adults that resembled the

170

A MATTER OF LIFE AND DEATH

immature growth stages of O. lapworthi. To cite one feature, the
single pair of spines on the edge of the cephalic shield of O.
lapworthi were positioned at the genal angle, more or less on a
level with the back end of the glabella. In various of these other
species the spines were shifted forwards, opposite one or another
of the glabellar furrows, so that the back border of the head
curved forwards to the genal angle. This is exactly what was found
in small growth stages of O. lapworthi, but lost in the adult.
Similar kinds of changes happened with the size and position of
the eyes. Most striking of all was a small trilobite with three pairs
of spines on the edge of the headshield, so spiky a creature that
it had been dubbed armatus by its discoverer, and so different
from Olenellus that it had been placed in a separate genus, Olenel-
loides. Ken McNamara realized that this oddity closely resembled
a 'blown up' version of one of the smallest growth stages of
Olenellus lapworthi. Not only that, this strange little animal only
had nine thoracic segments, compared with the fourteen or so
of O. lapworthi. Looked at in this light, O. armatus seemed to
cry out: T'm an overgrown baby!'

Ken arranged five Olenellus species (with lapworthi at the base)
in a kind of sequence of progressive babyhood, culminating in
O. armatus. He believed that O. lapworthi might have lived in
the deepest water, and considered that O. armatus probably lived
in the shallowest marine environment, with the other species
arranged in between. He speculated that warmer, shallower Cam-
brian environments stimulated earlier maturation. The five suc-
cessive species then slotted neatly into different ecological niches
related to water depth. However interpreted, Olenellus provided
the most vivid demonstration of how apparently major differences
between species may actually just be a question of altering rates
of development. O. armatus and O. lapworthi look like very
different trilobites - so much so that they had once been placed
into difi"erent genera - but they are fundamentally related, as
might be clocks with the same mechanisms but different faces.
Similar heterochronic variations have now been recognized in

171

TRILOBITE!

c

4-*

c
o
u

c

<u
00

o

-o

c

(0

3

4-J
CO

k<
u

E

^-*

00

c
t»

a

c

Time shifts: Ken MacNamara's diagram showing how successively younger
species of the early Cambrian trilobite Olenellus from northwest Scotland
resemble earlier and earlier growth stages of their ancestral species.

many different kinds of animals and plants: differential develop-
ment seems to be an important source of novelty throughout the
biological world. Olenellus's ancient example gives a new twist
to Wordsworth's aphoristic line 'The child is father of the
man'.*

If the child can become a precocious grown-up, there are also
counter examples, where the immature phase of a descendant
species resembles its ancestor. The descendant does everything
that the ancestor does during development, but adds on a little
more, a novelty of its own unseen in any earlier, or more primitive

* For those who like technical terms, this kind of heterochrony is known as paedo-
morphosis, of which Stephen 1. Gould and Ken McNamara have distinguished several
varieties. The 'paedo' root is Greek for childhood. Its mirror image, where new
features are added late in ontogeny of more derived species, is known as per-
amorphosis. Again, peramorphosis has been classified into several varieties.

172

A MATTER OF LIFE AND DEATH

species. This is the famiHar case of recapitulation, of 'ontogeny
repeating phylogeny', which biology students used to have
to learn as a kind of mantra. The grossly simplified version that
once portrayed the human embryo as passing progressively
through protozoan and fish on its way to mammal has long
been discarded. The living horseshoe crab, Limulus, was supposed
to have a 'trilobite larva' indicative of its common ancestry
with my favourite animals, but this is a resemblance due to a
shared simplicity as much as a shared ancestry. But legitimate
examples are still to be found in fossil lineages. Among the
pelagic, seafaring trilobites I studied, for example, huge-eyed
adults actually had larger goggle-eyes than their larvae and
immature growth stages, which were more like the relatively nor-
mal-eyed trilobite ft-om which they had descended. In this way,
development timing marched on beyond the ancestor; a good
new feature was exaggerated; and what started as a novelty became
an institution.

Trilobites can demonstrate seminal facts about evolution.
Modern biologists' evolutionary study has disappeared progress-
ively into the genome, and there it has wrought wonderful things;
but what is lacking is a time frame, case histories that see evolution
in process in real time and real space. Experimental biologists
have at most a few years to play with; to a palaeontologist a few
million is 'but the blinking of an eye'. Trilobites can, indeed,
provide evolutionary examples worthy of poor Dr Kaufmann's
young life. Changes in development timing, with their profound
results in shape, may be the result of no more than tinkering
with the genetic code. The molecular finger that resets the clock
may do it with no more than a insouciant tweak: even a single
gene might control the time switch that creates a difference as
profound as those between Olenellus lapworthi and O. armatus.
It is the job of molecular biologists to identify the controlling
genes (and I doubt not that they'll still be there tucked away in
the DNA even after 500 million years or more), just as it is the
duty of the palaeontologist to describe examples of the same genes

173

trilobite!

in action, and how long in geological time and space they take
to spin their creative magic.

There is no change without death. I have portrayed the creation
of a species, but not its destruction. The history of the trUobites
was a history of the passing of the old as much as the appearance
of the new. This turnover of species - life after death after life -
is the stuff of normal evolutionary change (scientists often refer
to it as 'background rates'). The better adapted replaced the worse;
or the species that originated allopatrically replaced another that
shared a common ancestor merely because climate changed to
favour an interloper. Life has always been a messy business, and
prosperity has alternated between luck and virtue in biology, as
in human affairs. Maybe we can turn to trilobites for objective
witness of the respective influences of chance and design. Their
molecules are lost for ever, naturally. But the signature that their
molecules left upon their bodies, which were saved in the geologi-
cal record, endures till rock crumbles.

Ultimately, trilobites did not cut the evolutionary mustard.
They were extinguished without progeny. My hope has faded
that, when today's mid-ocean ridges were explored by bathyscape,
in some dimly-known abyss there might still dwell a solitary
trilobite to bring Palaeozoic virtues into the age of the soundbite.
Sadly, there has been no trilobitic coelacanth to astonish biolo-
gists, no atavistic survivor who might answer directly all those
questions we would like to ask of the genes. Three hundred
million years was course enough.

Without death there is little innovation. Extinction - death of
a species - is part and parcel of evolutionary change. In the
absence of this kind of extinction new developments would not
prosper. In our own history, periods when ideas have been per-
petuated by dogma, preventing the replacement of old by new
ideas, have also been times of stultif)^ing stagnation. The Dark
Ages in western society were the most static, least innovative of
times. So the fact that trilobites were replaced by batches of

174

A MATTER OF LIFE AND DEATH

successive species through their long history was a testimony to
their evolutionary vigour.

Just as mechanisms for generation of new species can be under-
stood in the field and in the laboratory by studying trilobites, so
we can map out the reason underlying their slow decline. During
their heyday, hundreds of different genera were spread through
almost every marine habitat that we know. If you measure success
by sheer numbers and variety then the true Age of Trilobites
ranged from middle of the Cambrian to the Ordovician period.
But they were fecund throughout their history: even in the latest
strata to yield their remains several species can be found together.
It is tempting to portray their history as a rapidly building cres-
cendo followed by a slow diminuendo which lasted until silence
finally prevailed. Such an analogy would be misleading. As in
much of the story of biological diversity, trilobites prospered and
suffered setbacks by turn. Their extinction phases coincided with
those that affected many other kinds of animals. These were times
when the usual rates of extinction were accelerated, when losers
were weeded out and winners favoured to survive and sub-
sequently prosper. Some animals that appeared at about the same
time as the trilobites - clams are a good example - endured the
seesaws of fate alongside their arthropod contemporaries, and in
the end outlasted them all. With trilobites, there were many
casualties along the way. Extinction events close to the beginning
of the late Cambrian removed many trilobite families that had
appeared early in the history of the group. A better studied event
at the end of the Ordovician, some 440 Ma, extinguished many
more of the families which had given earlier faunas their particular
flavour. The tiny, blind agnostids, those enigmatic miniatures
from the Cambrian, disappeared. They had lasted nearly 100 mil-
lion years - reflect on the few millions of years that our own
genus has survived, and ponder the meaning of 'success'. Many
large trilobites related to Isotelus and Ogygiocarella also died out,
as did small ones like trinucleids whose medallion shields were
so typical of Ordovician strata - in fact, most of those animals

175

TRILOBITE

The head and tail of Mucronaspis (here from the Ordovician of Thailand) a
ubiquitous trilobite at the time of the great Ordovician glaciation.

Peter Sheldon studied in such detail perished without progeny.
Then, too, the free-swimming, giant-eyed, pelagic trilobites of
which I had grown so fond are never found again after the Ordovi-
cian, and I believe that trilobites failed to occupy that particular
ecological niche after that period. Olenids died out, my favourite
family from my Spitsbergen days, which had patiently prospered
ever since Cambrian times, holding their own against all comers.
Truly this was the end of a biological world.

The termination of the Ordovician was also when a great Ice
Age, centred upon the South Pole - which was at that time in
northern Africa - spread its refrigeration almost completely
around the world. Ice ages recur in Earth history, rarely and
irregularly, and always with profound effects. The Pleistocene Ice
Age with its woolly mammoths and cave bears was merely the
latest of them. Ice ages yield characteristic rocks, those dumped
by retreating glaciers or produced by the fallout from floating
icebergs. They share a kind of promiscuous variety: large and
small boulders or pebbles lumped and jumbled together, and
rocks of different origins all mixed up. Ice simply acts as a carrier,
and when it melts everything it picked up along the way just
drops. The resulting rocks have a lumpy texture, looking from

176

"%

kk

19. Crotalocephalus, The
glabella has become com-
pletely crossed by strong
furrows. The thoracic tips
are produced into long
spines, as is the pygidial
margin. The lateral view
shows how the thorax can
arch up, and shows the
convex eye lobe.
Devonian, Morocco.

j.iJMwyp.-.-j"iiii.

,y^'

20. ABOVE Acanthopyge, a trilobite related to Lichas the size of a crab with a vci \ peculiar
glabella, and a pygidium which is larger than the headshield. Devonian, Morocco.

21. ABOVE RIGHT A relative of ScuteUiiDi, Thysanopeltis, with an enormous, fan-1
pygidium which is much longer than the head shield. Specimens are often 10 cm
Devonian, Morocco.

22. RIGHT A cluster of five
Cyphaspis from the Devonian
limestones of Morocco; very simi-
lar trilobites can be found world
wide. This particular species had
a pair of 'devil's horns' on the
glabella. A long spine on the
thorax may have helped the
trilobite right itself if it landed
on its back; the pygidium is
comparatively small.

ike
long.

23- RIGHT One of the survivors
among the trilobites, Griffithides
from the Carboniferous
(Mississippian) rocks of Indiana,
USA, specimen about 5 cm long.

24. BELOW Paraharpes, a remark-
able animal in which the genal
spines are prolonged into a 'brim'
which extends alongside the
length of the trilobite. The outer
part of the brim is flattened for
resting on the sediments. This
trilobite has very degenerate eyes,
and numerous thoracic segments
(length usually 5-6 cm)
Ordovician, Scotland.

'&sm

^#i-T- -^^iv^,- ■■■^->' :sl

25. LEFT A close relative of
Ampyx ( Cnemidopyge) from
the Ordovician shales of cen-
tral Wales. A blind species,
which carries a spine on the
middle of its head like a
rapier. The genal spines are
equally long (the one on the
right is shown here) and
extend backwards beyond
the body of the animal,
which has sLx thoracic
segments and a strongly
furrowed pygidium.

26. BELOW Three blind trilo-
bites. A group of three speci-
mens of Conocoryphe from
the Cambrian of Bohemia,
Czech Republic, made
famous by loachim Barrande.
Two of the specimens are
preserved right way up, the
third on its back. Note the
comparatively small tail, and
fourteen thoracic segments.
This is one of many
Cambrian trilobites with a
'flowerpot shaped' glabella.

'im(\

Mrf^|:

^

27. RIGHT One of the
'strawberry headed
trilobites' of the Silurian
period, Balizoma vario-
laris, beautifully etched
out in natural relief
(about X 3). The pygid-
ium begins after the
twelfth thoracic
segment. The head is
richly covered with
coarse tubercles. From
the Wenlock Limestone
(Silurian) of Dudley,
Worcestershire, UK.

28. BELOW Pagetia, a
diminutive, flea-sized
trilobite with two
thoracic segments and a
long pygidium the same
size as the head. This
trilobite is related to the
blind agnostids, but
actually retains a small
eye set far out on the
cheeks. This example is
from the Cambrian
rocks of British
Columbia, Canada.

. T *

29. OPPOSITE ABOVE Seleuopeltis, a trilobite in which the tips of
the thoracic segments, like the genal spines, are enormously
elongated. This specimen is from the Ordovician shales of Wales;
similar specimens can be found in France, Spain, Czechoslovakia
and Morocco. These occurrences help to define the Ordovician
continent of Gondwana.

30. OPPOSITE BELOW A beautiful moulted cast-off exoskeleton of
Leonaspis. See how the free cheeks have been cast off to either
side as the facial sutures have been opened under the influence
of moulting hormone. The 'soft shell' trilobite crawled off for-
wards and away to grow a new hard shell. Specimen about 1.7 cm
long.

f

«
>,

'V-?fl

rv.

)'!'^

,r:

1^j:

?^''"

f~-'.4 .

31. Srto /nrsKfrt from the Cambrian of Bohemia (modern Czech repubHc). The growth from
babies of this species is illustrated on p. 216. This trOobite has a strongly furrowed glabella,
moderate sized eyes and tubercles on its cheeks. Sixteen thoracic segments and the
pygidium is small. Twice life size.

ft.

i

32. One of the plates from Barrande's magnificent work on the trilobites of Bohemia. Tl;c
original is quarto, and so the details are even clearer. These are odontoplurid trilobites.

fi*^ W,

33. Trilobites as sympathetic magic.
A piece of one of the Cambrian
'swallow stones' from the Cambrian
of Shandong, China, abounds with
heads and tails of at least three
species of trilobites (photograph
courtesy of Adrian Rushton)

34. The fantastically spiny trilobite Coinura,
from the Devonian of Morocco. The vertical
spines are a masterpiece of preparation from
inside the limestones in which this trilobite is
found.

A MATTER OF LIFE AND DEATH

afar like a badly cooked plum pudding. These characteristic tiUites
abound in many rock sections containing strata which were
deposited close to the end of the Ordovician, and associated with
them fossils can very often be collected which are known as the
Hirnantia fauna. {Hirnantia is not a trilobite - it is a brachiopod
the shells of which are typical of this Ice Age.) It is astonishing
how widespread the Hirnantia fauna is. A special trilobite, Muc-
ronaspis, is one of its typical denizens, but other trilobites are
usually very rare. It is recognizable by a little spike at the end of
its tail. I have collected it from a wet and breezy hillside in North
Wales, where Cwm Hirnant provided the inspiration for the name
of the diagnostic shell. I have collected it again in a humid quarry
in southern Thailand, where beads of sweat from my brow
blobbed on to the cephalic shields as soon as I wrested them
from their enclosing sandstone. I have seen the same trilobite
from shales collected from beneath the Tablelands of South Africa.
I have seen it from Poland, and Norway, and China. The implica-
tion is perhaps rather obvious, but no less interesting for that.
These were 'cool' trilobites. They chased out others from climates
which had been more temperate before the ice sheets advanced
- and the effects of the glaciation penetrated to the equator.
Mucronaspis imposed a uniformity almost as pervasive as the
blue suits that blanketed China during the ascendancy of the
Maoists. It is now known that extinctions also occurred in the
deep seas at more or less the same time as Mucronaspis spread
over continental shelves, and affected planktonic organisms as
profoundly. Many of the trilobites which became extinct probably
spent their larval life in the open sea as part of the plankton, and
this may have rendered them particularly vulnerable. Through
this critical bottleneck, only fortunate trilobites passed. There was
no way of knowing in advance that being 'cool', or not having
planktonic larvae, might equip for survival. These trilobites did
not store up the genetic equivalent of ships' biscuits to see them
through the hard times. Some simply possessed - by chance -
features that would serve them well in the crisis. This is an

177

trilobite!

important discovery about the very nature of mass extinction.
Who icnows if lessons may yet be drawn from my animals which
might influence the actions of another animal - the one e e
cummings called Manunkind? And who is now causing another
extinction as severe as that endured by the trilobites at the end
of the Ordovician . . .

But the end of the Ordovician was by no means the beginning
of the end for the trilobites. Families which passed through from
the Ordovician abounded in the Silurian - in fact, there may
have been almost as many species as earlier, but derived from a
more limited set of common ancestors. Crusty-headed encrinur-
ids and spiny-tailed Cheirurus grace many collections, and it is
tempting to believe that the evolving ecosystem prodded trilobites
into yet more inventiveness with their versatile exoskeleton. This
was the time when phacopids, with their clever eyes, started to
come into their own. Rock surfaces can be covered with them:
the Silurian sea-floor could be as crunchy underfoot as it was at
any earlier time. Many of these trilobites continued into Devonian
strata, which was the acme for all things spiny and blistered,
pustulose, scrofulose and carbunculate. But alongside such trilo-
bite extravaganzas were more ordinary citizens like Proetus which
might, at a glance, be mistaken for an average Cambrian or
Ordovician animal. It was Proetus and its allies {Gerastos page
180) that survived the next crises late in the Devonian - the
trilobites had by then enjoyed some 80 million years of plenty
since the last mass extinction. In some ways, the Devonian events
are more puzzling than the Ordovician. There are several of them,
one after the other, and each is associated with an invasion of
oxygen-poor waters over the continental shelves, which had the
effect of removing the coral reefs in which many trilobites lived.
This was more like death from a thousand cuts than from a single
assassination. The coup de grace was the Frasnian-Famennian
event (the name describes its stratigraphical level between two
geological divisions), which has been ascribed to a gigantic
meteorite impact - the kind of phenomenon usually cited as the

178

A MATTER OF LIFE AND DEATH

cause of dinosaur extinction, a catastrophic event which happened
180 million years after the last known trilobite.

Whatever the cause, after the Frasnian-Famennian only Proetus
and its allies survived into the Carboniferous. What had been
dozens of families had dwindled to a handful, aU of them closely
related. Even so, many new types of trilobites appeared as inno-
vations during the Carboniferous period. About twice a year I
get a parcel of papers from German specialists describing a new
batch of species - the discoveries never seem to come to an end.
Bob Owens from the National Museum of Wales has found new
forms in the familiar crags of the Carboniferous Limestone that
make up 'the backbone of England', the stone-walled, sheep-
studded uplands of the Pennines. Proetide trilobites spread out
into many of the ecological niches that had been occupied in
earlier times by trilobites from a richer selection of families. They
managed to play the same ecological tunes as their forbears, but
they used different evolutionary instruments. They spread into
deep water, and into newly re-established coral reefs. As a conse-
quence, some of these late trilobites came superficially to resemble
their ecological twins recovered from Ordovician, Silurian and
Devonian rocks. There were even some species that came to look
like Phacops - although they did not develop the schizochroal
eye . . . What a marvellous dissembler is nature! If I were of a more
anthropocentric cast of mind I might wonder if palaeontological
puzzles had been placed in the rocks simply to test the mettle of
scientific investigators. Biologists and palaeontologists seem to
spend so much of their time unraveUing the deceptions of nature.
Resemblance of shape is everywhere, for ecological necessity dic-
tates form: animals earning a similar living in the wild resemble
one another - bat and bird, skink and snake. To pluck out deeper
evolutionary truths, the origins of anatomical structures must be
recognized - what is termed homology. Homology reveals the
deeper concordances of genes and development against the Sirens
of overall resemblance. Is this glabella the result of a modification
from some deeper design, one which truly reveals common

179

trilobite!

LEFT Gerastos. Three fine
individuals of this neat Httle
proetide trilobite, which al-
most seem to be saying 'two's
company, three's a crowd'.
Large eyes are very close to
the glabella, genal spines are
shot, and thorax has ten seg-
ments. Devonian, Morocco.
(Photograph courtesy Prof.
Brian Chatterton.)

BELOW Oneofthelasttrilo-
bites, Ditomopyge, from the
Permian of Wichita, Kansas
- two views of an enroled
specimen, (x3). (Photograph
courtesy Bob Owens.)

BELOW LEFT Enroled ex-
ample of the Ordovician
trilobite Symphysurus from
Sweden, natural size.

180

A MATTER OF LIFE AND DEATH

ancestry with another trilobite altogether from one we had sup-
posed at first glance? Is what we see in morphology primarily
related to life habits, just as all 'flatfish', while doubtless flat,
may have come from more than one ancestor? Maybe, while he
contemplated Ogygiocarella, Lhwyd sensed the important resem-
blance - ecological equivalence - while making nonsense of true
biological affinity. A trilobite may yet be a fish in spirit. In palae-
ontology, as in human affairs, there is more than one kind of
truth.

By the Permian only a modest number of trilobites remained,
twenty or so genera. Even so, they can occasionally be common
fossils. The very last trilobites seem to have disppeared a little
before another great mass extinction at the end of the Permian;
by then, they were minor players in the marine drama. Their
great days had passed. These postscript animals are mostly found
in rather shallow habitats in what were tropical seas: perhaps this
made them especially vulnerable to climate change. I regret that,
unlike some of their contemporaries among the molluscs and
brachiopods, none of these late trilobites were adapted to deep-sea
life, where they might have seen out the traumas that swept across
the land and continental shelves. As it was, they were part of a
scene-change that presaged a new act in the story of life. I doubt
that we have yet discovered the very last species, that rare survivor
that still plied its Palaeozoic habits when the ancestors of the
dinosaurs were strutting around the streamsides of Gondwana.
The trilobites did end with a whimper rather than a bang. I am
reminded of the piece that Joseph Haydn wrote as a subtle protest
against the mean musician's wages at the court of Esterhazy. In
the final movement of the Farewell Symphony the musicians leave
one by one, while the music continues vigorously to unfold. In
the end a solitary fiddle carries on alone - and only then is there
silence.

181

VIII

Possible Worlds

I have spent much of my working life remaking the world. I have
pushed half of Europe across half an Atlantic. I have closed ancient
seaways and opened up others. I have been able to name an
ocean greater than the Mediterranean, and then condemned it
to perdition. My job has been to describe the outlines of vanished
continents, and to plot the seas around them: in short, to draw
a map of the Earth as it was nearly 500 million years ago. To do
this, I have used trilobites. When I meet some of my commuting
acquaintances on the 6.21 home to Henley-on-Thames they
occasionally enquire what I have done that day. I have been
known to reply: T moved Africa 600 kilometres to the south.'
They usually turn quickly to the soccer page.

One of the first books to open my eyes to the seductions of
the scientific method was a collection of essays called Possible
Worlds by perhaps the greatest of science writers. J. B. S. Haldane.
One of the chapters was called On being one's own rabbit, and
this spirit of experimental adventure was typical. It encouraged
me to speculate upon the many mysteries of the world, and how
unravelling one or two small ones might be the best thing to do
with a life. Now, by a twist of fortune, I am privileged to create
my own possible worlds: vanished worlds, written in a geography
generated in my imagination, and argued out with a dozen of
my colleagues. I have dreamed of chains of volcanic islands

182

POSSIBLE WORLDS

belching fumes and spewing lava into archipelagos swarming with
trilobites and nautiloids. I have seen these animals suffocate on
a ravaged sea-floor, killed and immortalized at one stroke. On a
Welsh mountainside I have tested the truth of such an ancient
tragedy by breaking a hard rock in which memories of volcanic
ash render the surface grey as woodsmoke, and in which lies
entombed the shadow of a trilobite, petrified to tell of its dreadful
end. In my mind's eye I have seen volcanic archipelagos collapse
and die as continent collides with continent, squeezed between
masses so vast that an ancient Stromboli might be as vulnerable
as a grape in a nutcracker. This is the Ordovician world, a globe
so alien that it bears little comparison with the atlas of today.
There is land and sea, to be sure, but the continents are not those
we have learned by rote in our first classroom. They are strange
shapes, curiously arranged.

It is not so long ago, geologically speaking, that our present-day
geography was a matter for speculation. In Hereford Cathedral,
in the middle of England, the Mappa Mundi is displayed in a
dim light for its own protection, but it seems an appropriately
mysterious illumination by which to inspect Richard of Hold-
ingham's parchment world of the late thirteenth century. And
what a curious construction it presents. With its domination by
land rather than sea, the Mappa Mundi looks quite unlike the
familiar Mercator projection of own world. In its centre lies
Jerusalem. The British Isles are placed on one edge. But the
cathedral town of Lincoln is portrayed with something approach-
ing realism: a street lined with houses runs down to the River
Witham from the cathedral on a hill. Like the famous cartoon
cover of the New Yorker showing a detailed Manhattan Island
from which the rest of the world retreats in ever sketchier outline,
Lincoln must have been the axis of the known world for the
creator of the Mappa Mundi, and the detail beyond was approxi-
mate. Travel was difficult; cartography was imprecise (and per-
haps Richard was as reluctant to explore as some New Yorkers
to venture beyond Brooklyn). At first glance, the lands around

183

trilobite!

the Mediterranean seem impossibly vague, but closer inspection
shows Cyprus and Sicily, almost recognizable. In the more remote
regions dwell monsters and giants: the satyr in Egypt; people
resembling birds (cicone) near Samarkand; in India birds called
avalerion which produce two eggs after sixty years, and then
drown themselves as they hatch; unicorns. The accurate cartogra-
phy of the Renaissance and beyond banished these mythical beasts
to ever more remote redoubts. Some would still have them lurking
in deep lakes in the Andes, or in remote Amazonia: the last hiding
places. In making geographical maps of the Ordovician I, too,
am sending dragons packing, firming up vague shapes, and restor-
ing some kind of truth.

The Permian Mappa Mundi, which is the continent of Pangaea,
has become almost familiar. The supercontinent that bound all
our present continents into one is numbered among those facts
that many people tend to pack away in their portmanteau of
memorable scientific concepts, like the notion that pi can never be
exactly evaluated, or that black holes eat matter. The persuasive,
complementary shapes of the coasts of eastern South America
and western South Africa now seem to make sense: they are a
legacy of the divorce of the supercontinent. The South Atlantic
ocean widened, progressively, from a fissure to a wide sea, as
oceanic crust was added at the mid-Atlantic ridge. Africa and
South America moved apart on their respective plates. What once
seemed an outrageous idea can now be accepted with a nod - of
course the continents were once united: it's obvious! India rifted
from the eastern side of Africa (leaving Madagascar stranded) -
and as it impinged on Asia squeezed into existence the highest
range of mountains on earth - the Himalaya. On satellite photo-
graphs the wrinkled range seems to crumple before the wedge of
the subcontinent, and one can almost feel the pressure that threw
up Mount Everest. From the vantage point of space, it seems as
if mountains can be made as easily as one may scrunch up a
tablecloth by leaning on a place-mat. The Alps, similarly, wind
in a line through Europe, a rumpled seam of tectonics that tells

184

POSSIBLE WORLDS

another tale of crust buckling under the motor of movement -
in this case movement of Africa northwards, shuffling a whole
series of plates across the Mediterranean. Pangaea broke up, a
marriage pro tem, a marriage made not in heaven but in the
tectonic basement of the world.

The unity of Pangaea corresponded with the trilobites' demise.
Some researchers have sought to relate the former splicing of the
continents to major extinctions, and it is unquestionable that
the newly annealed supercontinent created unusual conditions to
which few organisms could successfully adapt. As we have seen,
the trilobites were already vulnerable. But what of the earlier
history, when trilobites still ruled the world? (I realise I am being
over-emphatic in my imagery here, but just occasionally I lapse
from scientific propriety and cock a little snook at the hegemony
of the dinosaurs.) For twenty-five years or so it has been recog-
nized that Pangaea itself was but a phase in the history of the
continents. Plate tectonics did not begin with the break-up of
Pangaea, any more than it has ended with the volcanic eruptions
on Monserrat. Rather, the trajectories of continents are the surface
expression of the internal engine of the Earth, deep convection
driven by the heat of the interior carrying the superficial plates
like skin on a cauldron of broth: unstoppable currents, nearly as
old as Earth itself Before Pangaea there were other Possible
Worlds, other designs for the Mappa Mundi. Pangaea itself
accumulated from the collision of still earlier continents: it was
but a brief phase of unification preceded, as it was followed, by
a longer period when continents and oceans divided the earth's
surface piecemeal. These earlier continental masses came together
through tectonic evolution to stitch Pangaea together, like an
ill-made quilt. The substance of the earlier continents was the
same ancient, Precambrian continental crust that still makes up
most of Africa, North America (Laurentia), Siberia or the Baltic
Shield. But it was cut into different patches from those we recog-
nize on the school atlas. There was no obligation on the part of
Nature to use the same pieces to design an Ordovician continent.

185

trilobite!

Oceans once separated these earlier continents. The oceans
were destroyed little by little as the marriage of Pangaea was
consummated. Oceanic crust was obliterated by subduction where
plates plunged downwards into ocean trenches; it was the same
mechanism in the Palaeozoic as is seen today off the eastern
coast of Japan. Ordovician volcanic rocks yielding the remains
of trilobites may have been produced around islands comparable
to the great volcanoes of Indonesia - these are the explosive
expression of plate destruction; the trilobites are testament to a
sea troubled by blasts of steam and incandescent clouds of ash.

If the oceans of the Ordovician have vanished, how do we know
they were once there? If they had simply disappeared without trace
they would indeed be invisible now. But virtually all ancient
oceans leave their signature upon the Earth's surface. Continents
originally separated by oceans eventually collide with one another
and throw up mountain ranges - in just the same way as India's
collision with Asia generated the Himalayan ranges. Ancient
mountain ranges cross today's continents like old scars. These
linear wounds mark the course of the margins of former oceans.
Erosion over tens of millions of years has worn away mountain
chains of great age, so that they are low compared with the
comparatively juvenile Alps or Andes. Look at any topographical
map of Asia and you cannot fail to notice the Urals, winding
across the vastness of that continent all the way from the island
of Novaya Zemlya in the Russian Arctic (where my Oslo sage
Olaf Holtedahl established his reputation describing some of the
ancient rocks) southwards towards the Caspian Sea. It looks like
a seam, and that is exactly what it is: a mountain range marking
the seam between a Baltic and a Siberian plate. In the Ordovician,
these plates were far apart, an ocean apart: different worlds des-
tined to collide. They became annealed only when the ocean
between them had been entirely consumed by subduction - and
this unification happened long before the greater marriage of
Pangaea. The former existence of an ocean is betrayed by extinct
volcanoes of the type associated with subduction, or by volatile

186

POSSIBLE WORLDS

minerals and copper ores that leak up from the interior of the
Earth when oceans die. Very old plate boundaries may not be so
obvious, especially if they have been partly covered by younger
rocks. To reconstruct primeval geography the scientist must find
and unzip those old scars, open out once more the vanished
oceans, running the tape of time backwards, further and further
into the past. The more distant the past, the more the uncer-
tainties in positioning any continent, the more like Richard of
Holdringham we become. My travelling companions on the
Henley-on-Thames train might have asked, with some justice,
'Moved Africa 600 km? Why not 900 km? Or two thousand?'
For we struggle to know the Ordovician world imperfectly, like
trying to solve a jigsaw puzzle through the wrong end of a tele-
scope: a hundred kilometres or so can represent the temporary
amnesia of a bad afternoon.

So we have to forget the geography we know, and think afresh
of Possible Worlds. There are some tools to help us. Several
rock types contain magnetic minerals. The heavy, dark iron ore
magnetite was the material used first to investigate the properties
of magnetism by William Gilbert, court physician to Queen Eliza-
beth I, whose De Magnete (1600) presciently observed that the
Earth 'behaves like a giant magnet'. The magnetic field streams
between the magnetic poles just like the 'lines of force' that iron
filings trace on paper around a bar magnet. Accordingly, sus-
pended magnets inevitably point to the Earth's poles. Magnetite
is a common mineral in nature, often occurring as disseminated
grains in sandstones, scattered like seeds in a cake. When a rock
is deposited (or a lava erupted), if it contains magnetic minerals
they will acquire the magnetization prevalent at the time. This
magnetization remains, a fossil of its own kind, even when the
plate on which the rock ultimately resides may have moved far
from its place of origin. By making some comparatively simple
measurements on the angles of inclination and declination of
magnetism the position of the pole at the time of magnetization
can be recovered - like an accusing finger pointing polewards,

187

trilobite!

the rock magnetism betrays its place of origin. The ancient lati-
tude {or palaeolatitude) is revealed by this method, but longitude
is much less precisely constrained, so that the position of a given
continent is never exactly located. But these data provide a
wonderful starting point to reconstructing an ancient global geog-
raphy: so much so that palaeomagneticians are often referred to
as 'palaeomagicians' by their colleagues, with only a hint of sar-
casm. The further you go back in time, though, the more prob-
lems there can be, until by the era of the trilobites many of the
measurements of the palaeo-poles prove unreliable; rocks can be
remagnetized later, for example, or the signal can become cor-
rupted. This has led to conflicts between the palaeomagicians
and the palaeontologists, each defending their different ancient
geographical interpretations. Occasionally, these get to be shout-
ing matches. The palaeomagicians pronounce that only their sci-
ence is 'hard' science, and once I heard one of their number
pronounce that 'one palaeopole is worth a thousand fossils'. I
suspect that the same scientist would proclaim that one physicist
is worth a dozen palaeontologists - the misguided cad.

The use of fossils in reconstruction of vanished worlds has a
long and honourable tradition. Fossils were, after all, key ingredi-
ents in the arguments about the reality of Pangaea, and this before
many physicists had accepted the idea of a great continent. How
could you have such similarity between the floras and faunas of
Permian South Africa, South America and India unless they had
been once conjoined? Trilobites can be used to rehearse similar
arguments: we can use them to map ancient continents. They
swarmed in the shallow seas that flooded the interior of Ordovi-
cian North America; they abounded where the seas washed over
the frigid shores of Gondwana (see page 193); they crawled in
soft muds over what we now know as southern Sweden and
Estonia. The trilobites despise our political barriers: they follow
only the bidding of their own taste in geography. Trilobites that
lived in these shallow seas were influenced by climate and
environment, just as marine organisms today are different at the

188

POSSIBLE WORLDS

tropics and at temperate latitudes. Sea creatures have their own
thermometers, and most of them are picky gourmets about what
they eat, and where. Predators speciaHze on prey with the care
of a connoisseur sorting out a Chateau Lafite from a vin ordinaire.
Some animals revel in lime; others choose sand as a hiding site;
still others dote on sticky, black mud. In short, sea animals have
a sense of place, and trilobites were no exception.

When the Ordovician continents were dispersed around the
world's oceans the trilobites developed differently on separate
plates - especially when they were at different latitudes. Each
continent acquired a character of its own - perhaps I should
rather say a cast of characters of its own - and many of the
characters were trilobites. Map the trilobites and you map the
continent. With help from palaeomagnetism it is possible to pin-
point the latitude to which each set of trilobites was adapted.
Then, too, different rock types tend to accumulate at different
latitudes. If we can recognize an appropriate set of rocks then it
is possible to make an informed guess at the ancient environment.
Limestones laid down under tropical sunshine are distinctive
enough. They often form great thickness of strata which are con-
solidated from muds of calcium carbonate known as aragonite.
Today, you have to go to places like the Bahamas to find their
match. Collecting fossils from great cliffs of former tropical lime-
stones can be a dispiriting experience, as your hammer bounces
helplessly off the intransigent surfaces. With more experience,
you scan the rock face for little, tell-tale signs of trilobitic life -
a bit of a pygidium, perhaps, subtly projecting from the rock.
You curse the fact that limestone and trilobites are made of the
same material, calcite, as you try to lever out a block with your
precious specimens somewhere in the middle. I have lost two
fingernails this way. But the trilobites in limestone are usually
beautifully preserved - if only you can get them out. At the other
end of the ancient world, there were no limestones in areas close
to the poles. Shales are typical trilobitic rocks, from which whole
carapaces can be collected with ease, but they are seldom as

189

trilobite!

beautiful as the limestone examples. Thus sedimentary rocks,
fossil species, and palaeomagnetic measurements all contribute
to a picture of where any given locality was at the time when the
trilobites thrived.

Imagine that you are one of a team of alien geologists visiting
this planet 200 million years hence, after mankind's excesses had
sterilized the continents as naked as they were in the Ordovician.
The engine of plate tectonics would not have stopped, for all our
passing. Now imagine that Australia had been split apart - in the
same fashion as Pangaea was riven - into three great fragments,
which had drifted on their own course to Antarctica, perhaps,
Africa and Asia respectively. How could the alien palaeontologist
reconstruct the former antipodean continent? She might well
start by recognizing the geological integrity of each of the three
fragments. Next, fossil collections would soon reveal a strong
bond between these dispersed pieces - kangaroos, wombats, pos-
sums, koalas, and a whole battery of other marsupials would be
recognized as endemics shared between the three fragments. Place
them close together, and the marsupials had a home to match
their family resemblance. Unless the subsequent tectonics had
blurred the outlines, it might even be that the three fragments
would lock together in a manner as particular as a jigsaw puzzle
solved.

So with the trilobites: in this case, we are the visitors from the
future, and we travel to as strange a world. It may be objected
that Australia's marsupials are terrestrial animals, and therefore
a better guide to a former continent than animals that could
swim across seas. This is undoubtedly true. But the Ordovician
was very different from the present day because then the seas
extended much further over the continents than they do now.
Shallow seas were like evolutionary cooking pots for endemic
species. It would be the same today if the sea once more flooded
over the vast plains of Australia, seeping into what is now desert
and endless scrub. I have collected trilobites in the very centre
of Australia, in a spot so remote that even the dingoes were tame,

190

POSSIBLE WORLDS

and slunk up for a look at me. In the Ordovician, this same site
would have been as remote from the continent edge as it is today
- the sea had flooded an extraordinary distance. The dingo looked
at me with the same curiosity with which I gazed on a trilobite
never before seen by man - we were both aliens in our different
ways. From my vantage point on a low hill I could see far away
across the peneplain, a place where erosion had done its best, as
the book of Isaiah tells us, to make 'every hill and mountain low
. . . and the rough places plain'. It was not difficult to imagine a
warm, shallow sea drowning this barren land, and I could reani-
mate the trilobites in my mind readily enough - a sea thronging
with life. In the same rocks we found evidence of what proved
to be one of the earliest fish known to science: another alien.
Some of the trilobites proved to be as distinctive as kangaroos.

I will now try to draw an Ordovician atlas, my own possible
world, a Mappa Mundi of 470 mUlion years ago (see page 192).
Some landmasses seem nearly familiar. There is Laurentia - North
America and Greenland - united then as now. But it is lying
on its side, and the equator passes through its midriff. What is
(nowadays) its eastern side is different, too. It has 'bitten off'
part of the western side of the British Isles. The trilobites from
north-western Scotland and western Ireland are the same as those
from western Newfoundland and Greenland. The rocks from the
island of Skye - to which Bonnie Prince Charlie fled - are the same
kind of limestones, precipitated under the gaze of a tropical sun, as
are found in New York State. Conversely, only the western part of
Newfoundland is part of Laurentia, the Great Northern Peninsula,
that long promontory which sticks up like an optimistic thumb on
the side of the island adjacent to Canada, where trilobites and rocks
tell of connections with Nevada and Oklahoma.

Elkanah Billings, a pioneer palaeontologist in the middle of
the nineteenth century, named many of the fossils. His Bathyur-
ellus and Petigurus were trilobites belonging to a family, Bathyuri-
dae, which were as typical of the Ordovician tropics of Laurentia
as kangaroos are of Australia. Find these animals in the rocks,

191

TRILOBITE

Siberia

Laurentia

(N. America)

Australia

S. Am

Africa

Baltica

The early Ordovician World, 485 million years ago, as the trilobites reveal,
with explanatory map labelling the principal continents. This is a mercator
projection with the ancient equator through the centre. The upper map will
help you recognise the present day continents in their Ordovician positions.
The crosses on the lower map indicate the lines of latitude on present-day
geography.

192

POSSIBLE WORLDS

and you know that the ground on which you stand was part of
Laurentia. In Newfoundland, they are found only on the western
side of the island; their contemporaries on the eastern side are
utterly different. A suture representing a vanished ocean (called
lapetus) passed between the two sides of the island. In the early
Ordovician, the east and west coast of Newfoundland were as
widely separated by sea as Brazil and Nigeria are today. The
map of the Bathyuridae extends northwards into Scotland and
Greenland; Spitsbergen, my geological cradle, was part of the
same Laurentian continent. The telltale trilobites are there in the
Canadian Arctic in EUesmere Island, and in Alaska, and through
western Canada, and all down through the western part of the
USA into the Great Basin of Utah, Nevada and Idaho - then
across through Texas, Oklahoma, and up the western edge of the
Appalachians to New York State, where the omnipresent Charles
Doolittle Walcott first described Bathyurus. The labours of dozens
of palaeontologists mapped the course of the continent stamped
with the unmistakable signature of their trilobites. When I came
to work in Nevada, many years after my stay in Newfoundland,
I hammered out some of the very same trilobites under the fra-
grant pihon pine as I had first cracked from the hard limestones
in the Arctic, while being scolded by a tern whose nest I had
approached too closely. This striking similarity proves that in the
Ordovician the equator ran lengthwise through North America,
rather than the continent having the north-south orientation of
today. (This, I might say, is the simplest of the ancient continents
to illustrate.)

At the other climatic extreme lay western Gondwana. The name
of the 'Land of the Gonds' has a distinguished part in the story
of the recognition of Pangaea. The great turn-of-the-century geol-
ogist Eduard Suess used it to denote the concordance of geology
between South America, peninsular India and Africa (and now,
as we know, Antarctica also). They were conjoined in the Permian,
and then they were split asunder. But Gondwana existed long
before the Permian: it is one of the greatest parts of the Collective

193

trilobite!

Unconscious of the planet. Forged together in the late Precam-
brian, the basement rocks of Gondwana are more than half as
old as the Earth itself: incorruptible, unchanging through half a
dozen convulsions which affected vaste swathes of the crust. The
textbooks that I was brought up with referred to such ancient,
stable blocks as 'shields' (as in the Canadian Shield) and it is a
designation I like because of the connotations of shield as armour,
as something that resists attack. In the Ordovician the western
edge of Gondwana was close to the South Pole, which probably
then lay in northern Africa. The great continent mostly huddled
in the southern half of the world, but was so extensive that it
stretched all the way from pole to the equator, which crossed
through Australia. No present-day continent is comparable in
extent. Another suite of trilobites observed their loyalty to the
geography of Gondwana, just as the Bathyuridae had in Laurentia.
A third continent is known as Baltica. On present geography
Baltica comprises Norway, Sweden and the Baltic republics -
Lithuania, Estonia, Latvia. Eastwards, it extends as far across
Russia as the Urals. Recall that this mountain chain marked the
former edge of a continent, a seam only annealed when continen-
tal Asia was assembled by the collision of Siberia with Baltica.
Siberia itself was a separate plate in the Ordovician - all continen-
tal seams were unpicked then, all zips unzipped. I explored the
Ordovician of Baltica with a Swedish schoolmaster called Torsten
Tjernvik in 1975. He guided me around a succession of small
limestone quarries in southern Sweden, where the rocks lay hori-
zontal and undeformed - nothing had disturbed them since their
deposition about 450 milion years before my visit. What was
remarkable was how much time was distilled into so little rock. In
Wales, I was used to hundreds of feet of dark muds representing a
million or two years of sedimentary deposition. In Sweden, half
of the entire Ordovician timescale - 30 million years or more -
could be inspected in a single quarry. A single subdivision of the
Ordovician timescale could be as thin as a biscuit: in our jargon,
the sequence was condensed (deposition was very slow). Yet there

194

POSSIBLE WORLDS

were trilobites aplenty, and they were a different set of animals
again from those I had collected in Newfoundland. Big tails were
everywhere of a creature (related, but distantly, to Ogygiocarella)
called Megistaspis. Not a whisper of a bathyurid. Tjernvik was in
his eighties when I visited Sweden. His English was remarkably
fluent: he had learned much of his use of the idioms from the
novels of P. G. Wodehouse, and the result was charmingly anach-
ronistic. When a particularly fine Megistaspis turned up he would
say, 'absolutely top hole, old bean!'. If he wished to impart some
important item of information it would be, 'can I have a word
in your shell-like?'.* At the end of the day: 'Toodle-pip, old boy!'
Everything I saw showed me that Baltica was a separate continent.
Both the types of rock and the trilobites (and subsequently palaeo-
magnetism) suggested that Baltica was located at temperate lati-
tudes, midway between Laurentia and Gondwana in the early
Ordovician. As for the trilobites, they were 'absolute corkers!'.

There is something intimidating about long inventories of
names and places, and the capacity to remember such details and
directories can recall the extraordinary but pointless powers of
the idiot savant. Who really wants to know the day of the week
on which 29 February fell in the leap years of the last few cen-
turies? Even lists of trilobite names are tedious. But the patient
compilations of lists of fossils from dozens of localities provide
the raw ingredients for maps of distribution: these, in their turn,
describe the boundaries of former continents. This information
could scarcely be of more importance. Today lists - tomorrow
the world! So, to break my rule about avoiding lists, here is a
roll-call of some of the trilobites which are found in the earlier
Ordovician rocks of western Gondwana, and only there, and
lived in the cool waters close to the Ordovician pole: Neseuretus,
Zeliszkella, Ormathops, Ogyginus, Colpocoryphe, Calymenella,
Selenopeltis, Pradoella, Placoparia, Merlinia. . . as fine a parade of
classical tongue-twisters as you could wish, and I could go on.

* Wodehousian abbreviation of 'shell-like ear', a poetic cliche originally applied to
pretty females.

195

trilobite!

Ogyginus, a trilobite typical of Ordovician
Gondwana. An example from Shropshire,
UK. Life size.

Each one of these animals is distinctive; taken together they
describe half an ecosystem. I mention this list in particular because
it saved my scientific bacon.

England and Wales and the eastern part of Newfoundland
together comprise Avalonia, a name bearing the flavour of
Arthurian romance, but in fact taken from the part of Newfound-
land on which St John's is situated - the Avalon Peninsula. The
rocks tell us that eastern Newfoundland and Wales were once a
single entity; in contrast to east and west Newfoundland which
were separated by the lapetus ocean in the Ordovician. Avalonia
is what is termed a microcontinent - a relatively small fragment
of continental crust which may have a history of 'drifting' -
independent of the great continents of Laurentia and Gondwana.
Maybe the Arthurian connotation is not so inappropriate after

196

POSSIBLE WORLDS

all: Avalonia struck out on its own on a kind of geographical
derring-do, and its story is a tale of departures and skirmishes.
In the 1980s there was a scientific conflict about the position of
Avalonia relative to Gondwana. With my old friend Robin Cocks
- a brachiopod expert - I had proposed that in the earlier Ordovi-
cian Avalonia was probably part of Gondwana. In support I had
a list of Gondwanan trilobites from Wales and Shropshire: Neseur-
etus, Calymenella, Ormathops, Colpocoryphe, Ogyginus, Placoparia,
Merlinia. Now the importance of this tally will be evident: carrying
such a list how could Avalonia have been anywhere else? And
since there was nothing in common with Baltica either - not one
trilobite, hardly a brachiopod - we concluded that cool water
Avalonia must have been separated from temperate Baltica by
another ocean, which, in 1982, we called Tornquist's Sea. (Torn-
quist was a famous geologist who had worked on the critical
area.) This is how I came to name a vanished ocean. Later in the
Ordovician, changes in the trilobite faunas told us that Avalonia
had rifted off Gondwana and moved northwards over Tornquist's
Sea to collide with Baltica. I confess to a slight twinge of megalo-
manic satisfaction in playing god with a piece of land that is now
home to fifty million people.

Conflict arose because a palaeomagnetic 'fix' placed Avalonia
much nearer the equator and closer to Baltica, several thousand
kilometres fi-om our proposed position. As is usual with such
scientific rows opinions hardened almost immediately. We were
told bluntly that one palaeomagnetic data point was worth a
thousand trilobites. We riposted that if Avalonia and Baltica had
been so close how come all the fossils were so different - while
those of Avalonia were so like those of France, Spain, and North
Africa? It became a test case for us; 'soft' science versus 'hard'
science; fossils versus the machines! In the end, the fossils won;
Merlinia was victorious. Since Merlinia was named after King
Arthur's magician maybe the fate of Avalon should have been
obvious for thoroughly non-scientific reasons. It subsequently
proved that the palaeomagnetic 'fix' had been flawed, and a later,

197

trilobite!

better one agreed with the trilobites. Today, Tornquist's Sea is
marked on all the maps of Ordovician geography. It has crossed
over that mysterious line which demarcates what is still theory
from accepted fact. Trilobites triumphant. But as Avalonia moved
away from Gondwana towards Baltica, Tornquist's was itself sub-
ducted away; a new ocean appeared behind Avalonia in its stead.
What plate tectonics creates, it also destroys.

But what of Australia, on the eastern side of the vast Gond-
wanan continent? The western part of Queensland and the adjac-
ent areas of the Northern Territory were also flooded by that
pervasive Ordovician sea. When John Shergold and I travelled to
this remote area there was only the vaguest notion of what might
be in the rocks. This is country of peculiar emptiness. Hardy
eucalypts dot a vast semi-desert, where a few beef cattle eke out
an existence only if they are watered from wind-driven 'bores'.
The bores often turn dry or run to poison. Paved roads do not
exist. Beyond Boulia tracks drive into the nothingness, and there
are areas where 'gibber plains' of wind-polished stones render
the trackways virtually invisible. It is easy to get lost, and I spent
much of my time leaning out of the vehicle looking for broken
twigs that might indicate the former passage of a Land- Rover in
the last field season. The Fierce Snake lives in these wastes, the
most poisonous snake in the world, a creature so spectacularly
venomous that one of its bites can kill hundreds of laboratory
mice. It obviously needs to be an effective predator in this terrain
of thin rations - but why so outrageously lethal? After all, snakes
do not eat kangaroos. Surely this is the most literal example of
'overkill' in nature. The heat is relentless, but there is an exquisite
half-hour in twenty-four as the sun squeezes down into the hori-
zon, and the beer can is cracked open and the steak sizzles on
the fire, when you would swear that to work here was the greatest
privilege a scientist could earn. Those years of poverty as a
research student, the poorly salaried assistantship that followed,
suddenly seem worthwhile. 'I'm being paid for this,' you say to
yourself incredulously. Then it starts to get cold.

198

POSSIBLE WORLDS

Only once did my enthusiasm for the desert suffer a blow.
There are very few pubs in the outback and they are sorry and
functional places: a plain bar, wooden floors, a flophouse out the
back. Station hands collect their pay cheques after months on the
job, intending to go to Brisbane for the high life. They often get
no further than the first pub. Their money is credited on a 'slate',
and there they sit - or more likely stand - drinking it all away.
After a week or two of this a kind of dopey, surly aggressiveness
is the commonest condition: eyes hooded, boredom mired in
alcohol. They become what an Australian would call a 'ratbag',
spoiling for a fight. To go into one of these drinking dens with
a 'pommy' accent is just the stimulation they have been looking
for. 'Bloody poms - can't stand 'em,' they will announce, fists
clenching and unclenching. This is where the Wild West still
exists, this remote island within the Island Continent. Fights still
settle scores, real or imagined. To a natural coward like myself,
this is terrifying. After my first encounter with one of these drunks
I spent three hours speaking in a cod mid-European accent to
escape their further attention. It was hard for them to develop
an attitude to somebody who came from Wallachia.

Australian Ordovician tropical trilobites proved to be different
again. Separated by latitude from those of western Gondwana,
and by oceans from those of Laurentia, they, too, had evolved
their own signature. There were strange animals with lumps all
over the headshield that looked superficially like the famous
Devonian trilobite Phacops - except that closer inspection showed
them rather to be related to Dr Lhwyd's Ogygiocarella, and to
Asaphus (we named it Norasaphus). This was a fine example of
how trilobites living in similar habitats could come to resemble
one another - like different actors donning the same clothes
to play identical roles. This phenomenon is known as homoeo-
morphy. Where we pulled out these trilobites from the soft, limy
sandstones, living examples of the same thing were dozing the
heat away under the spinifex bushes: marsupial 'mice' are mouse-
like in design and habits, but they are truly marsupials along with

199

trilobite!

wallabies and koalas. Nature revels in such deceptions. Shergold
and I had just split another from early Ordovician rocks of the
outback showing the same trick more than four hundred million
years earlier.

It would be disingenuous to pretend that trilobites alone recon-
structed the Ordovician world, although they were crucial in
resolving some of the disputes. Somewhat regretfully, I have to
admit that my days of playing with cardboard cutouts of conti-
nents are over. Nowadays, information of such complexity has
to be handled by computers which can integrate information
from many sources, palaeomagnetism, trilobites, sediments and
all. Computers can handle all the problems of projection and
scaling that are indispensable to make sense of the results: worlds
can be swivelled with the flick of a switch. A computer has made
the Ordovician Mercator projection in which the Gondwana con-
tinent seems so strangely squashed about the bottom of the world
(it's the same projection effect that makes Greenland look so
triangular on many modern maps). You can understand what
Gondwana really looked like if you project from the pole as centre
as shown opposite. To a computer that is routine. But whatever
tricks are used it is always difficult to turn a sphere into a plane,
and worse still if the continental shapes are strangers to us. Com-
puter reconstructions are only as good as the information with
which they are supplied - the adage 'rubbish in, rubbish out'
applies just as much here as it does to dating agencies. Machines
have been known to line up sad mismatches of continents,
doomed never to make a successful marriage.

In this chapter I have described the world as it was for a few
tens of millions of years during the 300-million-year history of
the trilobites. It is almost a snapshot in time - a time slice might
be better - but it is a frozen Ordovician moment in a dynamic
history of a mutable world, for the continents hardly ceased in
their global peregrinations. By the Silurian, 45 million years later,
the ocean that had once separated Baltica and Avalonia from
Laurentia - lapetus - had disappeared, subducted away. The

200

POSSIBLE WORLDS

Ai

\

1

/3s

S^^

V

{U?

H/

V

^ ?"

' — <::

>

D»

\

^

^:^>'

Ordovician Gondwana from a polar projection, centred on
Africa, with peninsular India, South America and Antarctica
easily recognizable. The southern part of Great Britain is
the small promontory at the top of map.

great mountain chain - the Caledonides - running through the
Appalachians to Scotland, and thence to the mountainous f]ord
country of Norway, was the consequence of the subsequent conti-
nental collision, an engagement almost as dramatic and complex
as that which threw up the Alps 250 million years later. Trilobites
that had lived apart were brokered into a forced marriage. The
faunas changed in harmony with the geography. The eventual
re-opening of the Atlantic Ocean when Pangaea broke up long
afterwards followed - but only approximately - the same seam
as had been closed by the Caledonian orogeny in the Devonian.
As a result, fragments of the earlier continents were stranded in
positions far from their Ordovician homes: now, northern Scot-
land is on the opposite side of the Atlantic from Laurentia, to
which it originally belonged - contrariwise, the two halves of
Newfoundland are welded together today when they were origin-
ally far apart. Even as lapetus had closed, another seaway - the
Hercynian - opened up, running across central Europe and

201

trilobite!

further to the East. We have met this ocean already at the begin-
ning of this book, for it was close to one shore of this seaway
that Hardy's trilobite lived (had it not been fiction) and Corn-
wall's twisted cliffs and noble granites were the legacy of the
ultimate demise of that ocean in the next great tectonic cycle.
Earth, like a nagging conscience, reopens old wounds. Who knows
if some tens of millions of years hence Asia may again cleave
apart along the Urals? Who knows if new animals may yet evolve
at the bidding of a shattered homeland?

It would take a book as long as this again to relate the whole
narrative of the continents as seen through the eyes of the trilo-
bites that swarmed around them. Nearly three hundred million
years separates the base of the Cambrian 545 million years ago
from the eventual demise of the trilobites. This was a stretch of
time that saw the world remade twice. And with each reconsti-
tution of the geography my animals juggled and adjusted to the
new climatic and oceanic regimen, sometimes coming together,
at others rifted apart. Even now, there are scientific arguments
over where this or that great tract of land might have been in
the late Ordovician or in the early Silurian. No Mappa Mundi is
final, and other worlds are still possible. But there should be
enough here to show how geography and evolution have waltzed
cheek-to-cheek, and how trilobites give evidence of the changes
in partners in the dance.

Now, at last, it is possible to reconstruct the world of the trilobites.
We can finally observe the seas that they saw through their crystal
eyes. We can understand what Thomas Hardy's desperate hero
might have known if a flash of intelligence could have passed
between trilobite and man in that mad moment on the Cornish
clifftops, a brief vision to strip away the mask of deep time. In
the Ordovician, trilobites straddled the globe, from hot tropical
seas where corals were already constructing bastions we could
recognize as reefs, to cold polar seas where barren landscapes, as
yet ungreened, were eroding under the assaults of storms and

202

POSSIBLE WORLDS

floods that swept blankets of sediment out to sea to cover the
carapaces of our animals, until they at last yielded their secrets
to our hammers. We can see vast oceans where none exists today.
Across these oceans few trilobites could swim, except for some
bug-eyed species which braved tropical storms to spread around
the equator, as indifferent to oceanic distances as tuna. Each
ancient continent carried its own cargo of trilobites, swarming
in their millions. The seas advanced far over these continents,
and in the productive shallows specialized trilobites revelled in
their place in the ecology; for all its ahen setting there were still
roles - ecological niches - that would be familiar to us from
living seas. (No single trilobite ever ventured into fresh water -
if they had, some might still survive.) As it was, there were large
trilobites the size of a tureen, like Isotelus, which hunted down
small 'worms' and caused their smaller contemporaries to scuttle
away to hide, or roll up into protective balls. Some of these
comparative giants grabbed their prey with their strong limb bases
and shredded them into pieces, mangling their remains against
a fork at the back end of the hypostome. Some species may have
been able to stuff their unfortunate prey into an inflated stomach
underneath an appropriately inflated glabella (Crotalocephalus,
fig. 19). Crab-sized Phacops may have used its sharp vision accu-
rately to pinpoint its food in dim light. No primitive and unsoph-
isticated mud-grubbers these - they were precision-engineered
agents of destruction. There was camouflage, and there was con-
cealment. Spiny trilobites were tight as burrs when rolled up, and
just as unappetizing. Others may have decked themselves with
small organisms - sea mats or hydroids - the better to conceal
themselves in the thronging profusion of the Palaeozoic sea-floor.
Others again buried themselves in the soft sediment with only
their stalked eyes warily keeping watch by day, to emerge at night
to forage among the seaweeds. There were thick-shelled trilobites,
which lived close to the tide-line, scurrying in and out at the
sea's edge, antennae twitching to the chemical 'smells' of food or
danger, eyes sensitive to the least movement. These animals would

203

TRILOBITE

have seen things we shall never see, like tiny animals that have
left no fossil to tell us of their existence, or waving algal fronds
that decay without trace. Not all history is penetrable.

Wherever the sea-floor was soft, and charged with organic
matter, there were true mud-grubbers. Small trilobites, these, like
the Cambrian Elrathia (p. 233), they searched the sediments for
edible particles, incessantly shuffling about the bottom, ploughing
through the sediment surface, gleaners and cleaners. They left
tracks in a few places, ploughing furrows, braided and scratched
by their questing limbs, sometimes flanked by grooves cut by the
genal spines. Like footsteps imprinted on a sandy beach, most of
the tracks were doomed to erasure, the memory of an afternoon
forgotten in the morning tide. But if there were an influx of sand
at the right moment they might be preserved - a petrified moment
frozen into rock - an occasion when the dance to the music of
time left steps behind. Some of these mud-grubbers may have
ploughed below the surface layers of the sediment like so many
trilobitic moles. A thousand species of shrimp-like animals have
the same habits today. There were the foot soldiers of the trilobite
world, the lumpen proletariat, toiling away incessantly on the
sea-floor for a few short seasons. Trilobites with this habit usually
have the hypostome mobile, not rigidly attached on the underside
of the head, the better to scoop in their squashy and unprepossess-
ing nutriment. They all looked superficially similar, too, all the
way from the Cambrian to the Carboniferous, compact little
trilobites with genal spines and comparatively small glabellas, and
quite a few segments in thorax and tail - they needed limb pairs
for sorting out the wheat from the chaff in their diet of slurry.
Like the Good Soldier Schweik, they survived when other trilo-
bites, more showy, perhaps, or higher in the marine food chain,
failed to survive the extinctions at the end of the Ordovician and
late in the Devonian. We have found them with 'bites' out of their
sides - so some predators evidently found them tasty enough. I
might conclude that it is better to grovel hopefully and survive.

Then there were filter feeders. These were generally no bigger

204

POSSIBLE WORLDS

than the sediment grubbers, but their headshields were inflated
and convex, much more so than the body behind, creating an
interior chamber under the head. From the trilobite parade, step
forward Cnemidopyge, with its frontal spine Hke a lance in a
tourney, and Trinudeus, with its strange fringe of doubled-up
pits. Sediment was whipped up by the limbs into the head
chamber into a fine suspension, from which the edible particles
were sorted and ingested. Imagine stirring up a bowl of soup
and picking out the noodles. They were sluggish animals, these
mud-whisking crawlers, with weak muscles sufficient to propel
them from one spot to another to stir up their meagre rations
when they ran short. They rested on sled-like genal spines. Many
of them were blind, as if their quiet world was not too troubled
by predators. But when threatened they could flip their thorax
and tail under the vaulted head carapace, tucking away the soft
limbs from sight until the danger passed.

Predators, mud-grubbers, and filterers could live together in a
single community. Now imagine, if you will, a series of different
communities of these animals stretching away from the centres
of the drowned continents into the deeps that surround them.
Progressive depths and different habitats, and in each a host of
trilobites did their hunting and scavenging, their digging and
searching through sediments, and where mud was soft enough,
stirred it into suspension. In deeper environments where the
oxygen level was low, specialists like Triarthrus, described in
Chapter 3, took over from other trilobites in a habitat which
diced between plenty and death through suffocation. Above the
sea bed, little agnostids swam like animated lentUs. At dimmer
depths again eyes became useless. This was the territory of the
blind, where touch and smell outbid vision, a dark world of
palpation and subtle signalling. Around each ancient plate the
continental shelves were stacked in order, carrying tier after tier
of different trilobites, each minding their own particular business.
Now we can begin to understand how there can be so very
many trilobite species. Divided by habitat and divided again by

205

trilobite!

geography, trilobites dissected their world into throngs of niches:
this is how they became the 'beetles of the Palaeozoic'.

If we could have sculled over the Ordovician sea it would have
tasted as salty, sparkled as brightly under the sun, and been as
stirred by storms as the sea is today. On the horizon a smoking
volcano might bear witness to the unseen, ineffably slow but
inexorable creep of tectonic plates. We would, perhaps, miss the
keening cries of gulls, or the silver-sided flash of a shoal of fish.
If we threw a deep trawl over the side of the boat, when it is
retrieved and tipped out on deck it would have been churning
with trilobites. A monster, big as a serving plate, tries to make
good its escape by scuttling towards a sluice, its sight bedazzled
by the bright light of the surface. Most of the catch would be
small beasts - the size of beetles - some of them lying helplesly
on their backs, legs threshing ineffectively out of their watery
medium. In the bottom of the net there are some balls, round
as marbles: a closer look shows that they, too, are trilobites -
Bumastus perhaps? - tightly enroled against the shock of disturb-
ance. Their protective stance won't do them much good on dry
land, but as you lob one back into the water it falls back to the
sea-floor, dropping like a stone, and the trilobite finally crawls
away unharmed by its experience. Even the mud itself is heaving
with tiny trilobites, some as small as ladybirds. These diminutive,
blind mud-grovellers are among the smallest of their kind. As
you pick through the tangles of weed brought up in the trawl
a fantastically spiny trilobite is hidden away in the thicket, an
odontopleurid; ouch! you withdraw your probing fingers smartly.

Perhaps we should find out what else is in the catch, besides
trilobites . . . Picking through the residue there are some animals
that seem quite familiar: a few snails, easily recognizable rams-
horns, and a dozen or so small clams. There are shrimp-like
creatures, too, and bryozoans (sea mats, colonial animals often
forming patches on seaweeds), and a variety of seashells like
brachiopods, including one remotely related to some species still
living near New Zealand. So not everything is a stranger to us.

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POSSIBLE WORLDS

And delving further into the mud a host of worms of various
kinds are revealed - polychaetes and sipunculans - and if we had
been able to take a microscope to the mud itself we would have
seen single-celled organisms - foraminiferans - and bacteria,
which have been processing the waste of the seas since Precam-
brian times. The Ordovician marine world is a curious mixture
of strangeness and familiarity, and we, the fishermen, peek at the
nets agog, trying to identify what we know and acknowledge what
we don't. The trilobites are lodged in this betwixt and between
category, familiar as arthropods, yet strange in all their particu-
larities. If we now row the boat onwards into deeper water, and
trawl again, we will bring up another net-load of wonders, another
squirming mass of trilobite characters, few of them the same as
those from the previous haul. The sea is rich.

The biological world is composed of many small components,
yet everything moves together in the great dance of life. The
smallest organism has enjoyed a role in the scheme of things, a
locus naturae. Nature may have been profligate with species, but
every species has had a place in the connectedness of things. The
small truths of trilobites can be extended to interconnect with a
whole world. As a plea for interdependence of culture and science,
E. O. Wilson has recently made a case for the unification of
knowledge - what he termed 'consilience'. The trilobite story
retailed here shows a consilience of a smaller kind, wherein even
identification lists can be married with geomagnetism and plate
tectonics to give a portrait of a vanished Earth. The beauty of
science is not just the abstract purity of mathematical theorems,
which have been celebrated in the biographies of great prac-
titioners like Einstein, John Nash, or Heisenberg, or number
theorists and inventors of geometries and algebras. There is no
question that reductionist brilliance has yielded some of the great-
est triumphs of the scientific intellect. But synthesis can be almost
as important as analysis. The attraction of fundamental equations
is that they offer hope of an ultimate truth from which everything
else may be deduced, even our messy and irredeemably complex

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trilobite!

world. In following the trilobites we have been looking, instead,
at the fruitful marriage of different fields of knowledge, a kind
of Pangaea of thought. Or you could think of it as being where
different paths converge, like those footways on the Cornish
clifftops where Hardy's characters met their pivotal moment, and
where the path of the trilobite was joined with the trail of another
vanished ocean as revealed in the evidence of twisted shales. My
own footsteps, and the account in this chapter, have followed the
same pathway. We have explored a past of which trilobites were
both witness and victim: and they have been called upon to testify
in the reconstruction of their own times and possible worlds.
Then by a generous process of reciprocal illumination the world
so reconstructed helps us to know more of the trilobite. I see
nothing wrong in taking the path to this reconstruction by way
of poetic images. In a consilient frame of mind, everything may
contribute to an accurate description of the world. I recall two
lines from Thom Gunn {Moly, 1971):

Parrot, moth, shark, wolf, crocodile, ass, flea.
What germs, what jostling mobs there were in me.

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IX

Time

We all struggle with time. Mortality makes time our master, yet
we continue to pretend that we can bend time to our will: we
make time for things, people are said to die before their time, as
if we all, briefly, had a period when our existence and the time
of it coincide perfectly, as with a surfer successfully mounting
and moving with the curling crest of a wave. My children ask
questions that begin: 'In your day . . . ?' implying that in some
way my time has already passed; was it yesterday, perhaps, and
if so why didn't I notice? A palaeontologist has more cause than
most to reflect upon time: its measurement, its span, and its
consequences. Time can now be measured by the vibrations of
atoms to an accuracy which only the leading edge of technology
requires. A fraction of a nanosecond is irrelevant to our own
lives, and to the pace of a biological lifetime, although it may be
germane to the chemical changes that affect a single neuron in
the cerebral cortex. Our thoughts are flashes of inspiration, and
a flash is brevity itself. However, the duration of a single day is
probably our most natural biological temporal unit. When Scar-
lett O'Hara says, at the end of Gone with the Wind, 'Tomorrow
is another day!' we don't cry cliche, because we all recognize the
optimism of a new morning. Witnesses in court are expected to
recall a single day; not even an American attorney-at-law would
demand a narrative of seconds. The great Argentinian writer

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trilobite!

J. L. Borges has a short story, 'Funes the Memorious', about an
unfortunate soul who recalls everything - together with every
interlinking ramification - and whose mastery of time has the
effect of paralysing him completely. We function thanks to a kind
of selective amnesia. This does not release us (especially scientists)
from the obligation to speak the truth, a rule which, as we shall
see, has been broken even by trilobitologists.

The reader will by now be either insouciant or bewildered in
the face of hundreds of millions of years. I have been waving the
continents past, ten million years at a shot, with a flick of my
wrist. The Cambrian was 545 million years ago; the Devonian
lasted for 50 million years. It might be thought that this broad
scale pertains to the time of the trilobite; the further back in time
the less precision, a few million years is nothing to notice. To
the trilobite. Mankind's dominion of the Earth is less than the
duration of a single species of their kind. All this is true, yet it
is still possible to look into a day in the life of a trilobite - to
cheat the great reverse telescope of time which makes distant
events seem so small and so far away. Sediment surfaces can
preserve a mere day, a true diary of Palaeozoic life. If that day
was buried fast enough it may yet be disinterred.

I have already described trilobite enrolment - the instant
response to threat which became a time capsule, a moment's
panic solidified. Then I have described how trilobites grew by
moulting. Their cast-off exoskeletons are testimony to the
moment of sloughing off the old coat before growing the new.
Sometimes the pieces are cast aside as carelessly as teenage chil-
dren cast their garments on the bedroom floor. In other cases it
is clear that the trilobite adopted a careful strategy for moulting:
after all, it was the most vulnerable stage in the animal's life and
caution was at a premium. It was not just the hard shell that was
moulted: even the finest hairs on the limbs shed their coats at
the same time. Where the sea floor was calm, the cast-off shells are
left undisturbed and you may sample the anxiety of the moulting
moment for yourself. Imagine, you are sampling a few snatches

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TIME

of time from a larger lifetime, itself a fragment of the time of
endurance of a species, which is but a brief instant in the compass
of geological time. You can relish the privilege of catching an
ancient moment.

Moulting was preceded by a phase in which a special hormone
softened the ventral cuticle (see fig. 30); the sutures which crossed
the head would then have loosened. When the moment came,
many trilobites used their genal spines as levers dug into the
sediment to release the free cheeks from the rest of the cephalon
(the hypostome was shed at the same time). Since in the majority
of trilobites the eye surface was attached to the free cheek this
most delicate part was released of its old corneal covering at a
helpful early stage. In primitive trilobites this same surface could
be shed separately thanks to a suture running all around the eye.
The cheeks gone, a gap opened at the front, and the trilobite
could then wriggle forwards out of the rest of its exoskeleton,
leaving behind a cranidium and thorax to tell of its adventure.

This was often not as easy as I have described, and the thorax
will be found separated from the pygidium, or the trilobite will
have crawled off with the cranidium still attached obstinately to
its head; the trilobitic equivalents of those terrible tank-tops that
you can somehow never get out of There are trilobites that gave
the process a hand by inverting their head and scraping off the
cranidium; this leaves the cheeks to either side with an inverted
cranidium between them - and behind the thorax and pygidium,
right way up. In trilobites like Phacops, in which the functional
sutures on the head have been lost, the whole head often gets
inverted, or the trilobites may even have moulted upside down.
The observer really feels as if he is watching the most personal
gymnastics. Some trilobites may have mated at the 'soft shell'
stage, as do many living arthropods, and this would have added
an extra urgency to the whole procedure. The Palaeozoic sea
would have been soaked in hormones - ecdysial, pheromonal,
spermatogenic. There are a few examples of 'soft-shelled' trilobites
preserved, killed before their new carapaces hardened: they have

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TRILOBITE

a kind of ghostly quality, a thin and feeble shadow of the real
Phacops. Some of these animals may have hidden quietly away
during this critical stage; my colleague Brian Chatterton tells me
of a Devonian burrow in soft sediment (presumably made by
some other animal) packed with trilobites in the process of grow-
ing their new shells. The burrow served to bury them rather than
protect them: the brief time of their tragedy served to ensure the
greater time of their survival as fossils.

I mentioned the growth of an individual trilobite when I
described evolutionary mechanisms in Chapter 7. Such growth
defines a lifetime, the most intimate of all temporal scales, birth to
death. It is extraordinary how much we know about the trilobite's
personal trajectory. Since trilobites moulted - casting off their
stiff exoskeleton and growing a new, larger one - it is an obvious
question to trace the same species backwards in time, looking for
smaller and smaller carapaces. What was needed was an unusual
place where juveniles and adults were incarcerated in the rocks
together, undisturbed. Such a locality was discovered 'under the
pear tree' in one quarry in Bohemia by arguably the greatest
name in trilobite research, Joachim Barrande (1799-1883). In what
is now the Czech Republic there are remarkably rich sections of
Palaeozoic rocks, and Barrande set out to be their biographer. In
the Rare Books Room of the Natural History Museum in London
a privileged visitor can inspect a shelf-fuU of large volumes, each
bigger than a telephone directory, the fruit of Barrande's own
lifetime of labour: the Systeme Silurien* de la Boheme. To students
of trilobites these are the nearest thing to holy tracts. Plate after
plate of beautiful lithographs (for most of his life Barrande
employed the best artists) delight the eye today, as they must
have astonished his contemporaries, (one is reproduced at fig. 32).
It is debatable whether the most sophisticated modern photogra-
phy could do better.

Barrande did more than treat trilobites; he described molluscs

* Recall that in Barrande's time, what we now know as Cambrian, Ordovician and
Silurian were all subsumed under 'Silurian'.

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TIME

A trilobite moult, Paradoxides, the giant Cambrian trilobite, this example from
the Middle Cambrian of eastern Newfoundland. Paradoxides is frequently as
large as a lobster. Notice the fat glabella and the long spiny thorax with spines
extending beyond the small pygidium. In moulting, the free cheeks have been
reversed and lie under the rest of the body twisted into this position as the
trilobite shed its 'old' skin, or exoskeleton and crawled away forwards. Specimen
about 15 cm long. (Photograph courtesy H. B. Whittington.)

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TRILOBITE

Joachim Barrande, the great Bohemian palaeontologist
and namer of trilobites.

and corals and many other fossils besides. However, he did lavish
special attention upon them, beginning in 1852, drawing upon
collections made for the first time from unusually fossiliferous
localities. By the end of the nineteenth century every specialist
was familiar with the localities we know today as Sarka and Kraluv
Dvur. There is a smart suburb of Prague known as the Barrandov,
where you may have a drink at the Trilobite Bar. In fact, almost
all of this beautiful city is deeply trilobitic. Barrande himself
started his career by accident. He found two pygidia of the trilo-
bite Odontochile rugosa close to Zlichov Church during a Sunday
stroll. He took them home, but his housekeeper Babinka* threw

* Barrande later named a fossil clam Babinka in her honour - if having a clam
named after you is not, rather, a veiled comment.

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TIME

them out (wives have been known to do this before and since).
Joachim made her retrieve them, and his Hfe work was ordained.
These two specimens, together with the rest of his huge collec-
tions, reside in the Narodny Museum, a grand, columned building
which looks down the length of Wenceslas Square in Prague.
They are treated with a reverence usually accorded to saint's
bones. The visiting scientist will be brought them two at a time,
each one immaculately labelled with the original figure of the
great man. In his honour a huge plaque was erected on a Devonian
hillside in Prague, just one year after his death.

One of Barrande's books describes what we would now call
Middle Cambrian trilobites; one plate shows a sequence of a kind
related to Paradoxides davidis, a trilobite I first encountered in
the cliffs at St David's, Wales, in my early days. In Bohemia,
Barrande discovered the whole growth series ft^om babe to adult
- a nursery preserved. Since the adult could be as large as a
lobster this was a wonder indeed, for the smallest babies were
hardly larger than a pinhead. Another species, Sao hirsuta, was
laid out in even more detail. I visited the famous pear tree near
the Bohemian village of Skryje some years ago - it was shrunken
now, putting out only a few, sad leaves, I doubt whether Barrande
would have recognized it. There were still a few larvae to be
discovered in the shales from the quarry beneath it.

Throughout growth, trilobites changed in appearance, but
nowhere more so than when they were very small. The trilobite
grew - moult by moult - from a tiny individual the size of a
pinhead. Barrande recognized that trilobites got larger by the
progressive addition of thoracic segments up to the maximum
number characteristic of a given species: if a trilobite had eight
segments, like Lhwyd's Ogygiocarella, the babies would add seg-
ments one at a time until eight were reached, and after that
would continue to get larger moult after moult without any more
segments being added. Trilobites were not at all like those
scuttling turtles beloved of natural history programmes which
hatch out as ready-made replicas of their parents, but changed

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TRILOBITE

The growth of the Cambrian
trilobite Sao hirsuta from the
Cambrian of Bohemia. The tiny
larva, or protaspis, is shown top
left. The progressively larger
growth stages have additional
thoracic segments, until the
adult number is reached. The
smallest two stages are a
millimetre long or less. The
specimens illustrated show,
progressively, one thoracic seg-
ment, three thoracic segments,
four thoracic segments, six
thoracic segments and thir-
teen thoracic segments. At the
six thoracic segments stage it is
just over 2 mm long, e - marks
the eye position in the larva.

216

TIME

subtly at each moult. The final number of freely articulated thor-
acic segments (at which the trilobite is said to have reached the
holaspis stage) was often acquired when the individual was still
only a fraction of its maximum size. The holaspis stage was pre-
ceded by a series of moults in which thoracic segments were
'released' progressively into the thorax: usually, the smaller the size
of the larval trilobite the fewer the segments. Taking this process
back to the beginning, at a size of a millimetre or so there were no
free segments at all: a proto-cephalon was articulated directly
against a proto-pygidium with no sign of a free segment inter-
polated between them. One stage earlier, the first larva of all con-
sisted of a single shield - in which head and tail were combined into
a minute disc, termed the protaspis. In some species the protaspis
can be less than a millimetre long. The protaspis hatched out of an
egg, no doubt, but claimed fossils of trilobite eggs are contro-
versial. Were it not for the fact that the protaspis is seamlessly
connected with intermediate growth stages that connect in turn
with the adult trilobite, it is perhaps rather unlikely that these
tiny objects would have been recognized as larval trilobites at
all. Most of Barrande's protaspides show traces of the trilobite's
eponymous 'three lobes', particularly the outline of the glabella,
even at this minute size (many others don't). But the transforma-
tion of a flattish tiny disc into a great predatory Paradoxides is a
metamorphosis indeed, a life story flushed ft-om the rocks in spite
of its immense geological age. It is as intimate a story as the
familiar change from caterpillar to butterfly.

It is likely that the earliest growrth stages of many trilobites
were part of the plankton, feeding upon tiny plants, or maybe
other larvae, just as baby barnacles or shrimps do today. At some
early point in the life cycle the larvae would have settled to assume
the beginnings of adult life on the sea-floor. When silicificd trilo-
bites were discovered, it was not long before the most beautiful
early larvae were recognized among the 'fines' in the bottom of
the sieve. Fitting the larvae to the correct adults was a matter of
skilled detective work, based on finding transitional sequences to

217

TRILOBITE!

Electron micrographs of protaspis larvae of Cybelurus from
the Ordovician of Spitsbergen. These single shields show
the minutest details, even though they are only a millimetre
long. The lower larva is the larger and already shows the
proto-head and proto-tail.

a known species. I was lucky enough to find some wonderful
protaspides firom the Ordovician rocks of Spitsbergen, which are
shown in the figure above. These were preserved in calcium
phosphate, which replaced the original thin calcareous shells, and
so perfect was the replication that tiny spines a few thousandths

218

TIME

of a millimetre across are faithfully recorded; just because some-
thing is small does not mean it is featureless. Among this cornu-
copia of microscopic life there were one or two specimens that
resembled balloons - but balloons that carried a couple of horns.
Harry Whittington had fitted them to an adult that looked very
different, Remopleurides. Those trilobites related to our old
acquaintance Ogygiocarella had rather similar smoothed-out lar-
vae - and so, indeed, did Trinudeus; no trace on the babies of
the fringe that makes the adult so distinctive. My Canadian col-
league Brian Chatterton thinks that these tiny lentils were
specialized in several ways for life in the plankton. Their under-
sides were almost entirely sealed in by spiny proto-hypostomes,
just leaving holes big enough for three pairs of tiny, thrashing
limbs. In freshwater ponds you may occasionally see clouds of
minute 'water fleas' (cladocerans) beating their way in automatic
frenzy through the algal-rich water. My father used to catch them
in great numbers and sell them on as fish food in his aquarium
shop. My vision of the Ordovician sea and its trilobite plankton
is coloured by afternoons spent peering into ponds at a vibrating
mist of zooplankton. Unlike water fleas, the flea-like trilobite
larvae underwent profound changes and grew to a size that might
be a hundred times that of the larva.

Naturally, there would have been no baby trilobites without
sex. Sadly, we do not know as much as we would like to know
about the sex lives of trilobites. If they were like many living
marine arthropods it is likely that the eggs were deposited by
females and then fertilized by males. There are several ways of
accomplishing this, the simplest of which is for the male to release
his sperm into the water where it is free to wash over the laid
eggs. It has proved remarkably difficult to recognize the two sexes
in trilobites. Nobody has identified any genitalia in the animals
that preserve the soft anatomy; nor are there obvious secondary
sexual characteristics, like the 'claspers' that certain male
shrimps use to hang on to females. For most trilobites la difference
must have been subtle. In 1998 my colleague Nigel Hughes and

219

trilobite!

I recognized what we thought might be the female trilobites of
a few species. These shared a pecuHar feature: a swelhng in the
middle of the head in front of the glabella. In some examples the
swelling was spectacular. There are living arthropods with such
swellings, which are known to function as brood pouches for
carrying eggs and larvae. Perhaps this was the trilobitic equivalent
of a portable creche? What gave this explanation an added fillip
was the position of the pouch.

A few years earlier I had been choosing my supper in a seaside
restaurant in southern Thailand when my attention was caught
by the live tank, in which various delicacies are permitted to crawl
about prior to being despatched for the table. Among them was
a horseshoe crab, Limulus or one of its close relatives, slinking
dejectedly among the more tasty-looking fish and crustaceans. I
was captivated. Limulus is the closest living relative of the trilobites
(p. 151) - a second cousin, perhaps. Its larva has been known for
a century as 'the trilobite larva' and does, indeed, have a passing
resemblance to the protaspis stage of my own animals. This could
be my best chance to find out what trilobites actually tasted like!
I ordered the dish. When it arrived I was surprised to find the
whole creature had been steamed, and it looked very unappetizing.
My amazement increased as the underside of the headshield was
lifted outwards - what we would call the doublure in trilobites
- and there inside the head was the edible bit of the animal: big
yolky eggs. Horseshoe crabs evidently carried their eggs in the
head region, unlike shrimps and other crustaceans that carry them
under the thorax. This was exactly the same position as the
inflated bulbs on the front of the trilobites; circumstantial evi-
dence, of course, but much better than no evidence at all. And
the taste? Even mixed with abundant noodles it was rancid and
intense. I like to think that trilobites would have tasted sweeter.

The trajectory from protaspis to adult is called the trilobite's
ontogeny. All complex animals have an ontogeny - our own, from
fertilized ovum through curled embryo to the developing foetus
and baby, being only the most familiar. Detailed study of trilobite

220

TIME

ontogeny has proved unexpected things. I have already described
a mechanism for introducing evolutionary novelties, by playing
around with timing of development. Many trilobites that are
tiny as adults may have been derived from more normal-sized
ancestors by becoming precociously sexually mature. Study of
growth trajectories revealed this possibility. Identification of early
growth stages showed that some trilobites are more closely related
by virtue of having very similar larvae than would be guessed by
a glance at the comparatively distinctive adults. Larvae can strip
away history to the root of descent. This is not quite the dictum
taught to all zoologists fifty years ago that 'ontogeny recapitulates
phylogeny - it might be better expressed as: 'by their babes ye
shall know them'. So the larvae tell us Calymene is probably
related to Phacops; Elrathia to Triarthrus. The trilobite world
is still in the middle of unravelling these connections: a new
classification of the whole prolific catalogue may result. It is a
wonderful thing to be able to see the Trinucleus fringe develop:
it starts as a single row of pits, and gets wider, and the rows of
pits organize themselves into a stippled symmetry. You can watch
the spine on Ampyx grow through ontogeny, like Pinocchio's
nose under the influence of an untruth. Harry Whittington dis-
covered that even the earliest meraspis Ampyx, with no thoracic
segments, could still enroll. As a trilobite, it seems, you could
not be too small to need protection. Odontopleura and its relatives
are spiny even as larvae, a nasty mouthful from the first. No
protaspis stage has been discovered for the most primitive trilo-
bites: Olenellus and Agnostus may even have lacked this stage -
unless it was not calcified. They begin their trajectory as earliest
meraspides.

As to how the thoracic segments are released into the thorax,
I have mentioned that James Stubblefield demonstrated in 1926
that they 'bud off' from the front of the pygidium, rather than,
say, being released from behind the head. He used the growth
series of the small Ordovician trilobite Shumardia to show this.
Shumardia has one extra large (or macropleural) thoracic

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TRILOBITE

X 4-0

The ontogeny of Shumardia. In 1926 Sir James Stubblefield showed how
trilobites grew by releasing segments from the front of the tail. The largest
Shumardia are only a few millimetres in length.

222

TIME

segment, the fourth one of the six segments present in the adult.
Shumardia is Hke other trilobites in the way it grows. It starts as
a tiny protaspis shield; then a boundary appears defining the
proto-head from the proto-pygidium; then as it continues to
moult and grow first one, then two, then three, then four, then
five and finally six segments appear in the thorax. During this
development the large, macropleural segment appears in the
thorax as the last, fourth segment at the four-segment stage of
development. At the five-segment stage it is still the fourth seg-
ment - and a normal-sized segment has been added on behind
it. In the adult, two normal segments have appeared behind the
macropleural one. In other words, segments are added behind
the macropleural segment which then shuffles forwards in the
thorax as adulthood is approached: segments are budded off the
front of the tail. I restudied Stubblefield's specimens sixty-four
years after his paper, and found his account exact in almost every
particular. Since 1926 his observations have been confirmed on
many other trilobites He was nearly a century into his own
ontogeny when this book was written in 1999* and was known
(even by Lady Stubblefield) as 'Stubbie'. After his seminal trilobite
discovery he rose through ranks of the Geological Survey of Great
Britain to become its Director, and eventually was dubbed Sir
James. Thus, the trilobitologist who rose the highest did so by
making the most minute observations on the smallest of trilobites.
In the late 1980s my colleague Bob Owens and I started collecting
in the same brooks and dells in Shropshire as had Sir James half a
century earlier; from somewhere Sir James rustled up a copy of the
original paper he had written on the subject, in 1927. On the cover
he wrote, in blue ink: 'With somewhat belated greetings . . .'

Then there are trilobite tracks, the imprint of a moment, maybe
of one feed in a lifetime. Can fossil time be more fleeting?
Assigning a trilobite species to a particular fossil track has proved
difficult. Tracks tend to be preserved in the kind of sandy sedi-

* He died whilst this booi< was in press.

223

trilobite!

Sir James Stubblefield (right, with pipe) en route to Shetland and Orkney in
1936, with two of his colleagues from the Geological Survey

ments in which body fossils are rare. After all, you would be very
surprised to find a dead body at the end of a set of footprints
on a sandy beach. Doubtless other arthropods could make tracks
somewhat like the trilobite's. So how to finger the culprit? A few
years ago in the Sultanate of Oman I was doing fieldwork on
some hitherto unexplored Upper Cambrian rocks, perhaps 480
million years old. Trilobites were fragmentary and rare, but since
they may have been the only ones of this particular age on the
whole Arabian Peninsula they were clearly worth the effort. It
was a remote area, the Huqf, almost lacking vegetation except
for one, improbable tree. Sandstones and Hmestones formed low
bluffs, so if you followed a single bedding plane you could crawl
on your hands and knees over a Cambrian sea-floor which pre-
served every scratch and footprint. All the signs in the sedimentary
rocks pointed to the rocks being laid down in very shallow seas
- indeed from time to time the water retreated to the point where
it started to evaporate to salt. Few trilobites relished living in

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TIME

such shallow water. The exciting discoveries were beds of beautiful
tracks; most unusually, the rocks that filled the tracks actually
contained the remains of trilobite shells of one special species
that evidently liked inshore life. Could we link the tracks and the
animal that made them? If the trilobites made the tracks then
they should match for size.

In 1994, I returned to the Sultanate with the great German
palaeontologist Dolf Seilacher, doyen of fossil tracks. Together,
we spent several days measuring track sizes and collecting trilo-
bites. We gingerly turned over slabs, on the underside of which
the casts of the tracks were best preserved. The caution was
prudent, because under some of the plate-sized pieces of rock
scorpions lurked during the daytime. I learned from my Omani
hosts that the big black scorpions, large as king prawns, were less
to be feared than the rock skulkers, half the size and yellowish,
which carried their stings sidewise, like a lariat. In this empty
desert I became aware of the most exquisite connection between
these scorpions and the trilobites in the rocks that sheltered them.
Scorpions are a kind of arachnoid, that great group of arthropods
that includes spiders and mites, together with the most primitive
living member of the group, the horseshoe 'crab' - whose eggs I
had been lucky enough to sample in Thailand. Modern studies'*^
of the evolution of arthropods as a whole have shown that the
trilobite's closest relative in the living fauna is Limulus, with
scorpions at one further remove. So in this remote corner of
Oman I could pay homage to a meeting across vast stretches of
time between ancient relatives: scorpions and trilobites. In the
early desert morning, you can see scorpion tracks prodded in
ranks across the sand, within a few centimetres of the ancient,

* These studies are based on cladistic analyses, as described in Chapter 5. Such
analyses derived from living and fossil arthropods have rejected an earlier idea that
trilobites were closest to crustaceans in favour of their inclusion in a great arachnoid
clade. Trilobites retain antennae, which are lost in the other arachnoids, or che-
licerates. As this book was being completed a new developmental study has shown
that the antennae might actually be homologues of the chelicerae, the curious frontal
appendages shared by the living arachnoids.

225

TRILOBITE!

Trilobite tracks. A cast of the furrows left by ploughing trilobites. Cruziana
semiplicata from the Upper Cambrian of the Sultanate of Oman. The longest
diameter of the specimen is 17cm.

fossilized tracks we studied. Dolf assured me that similar scorpion
tracks could be found in rocks as old as Devonian. Think of the
trilobite Phacops still flourishing in hordes at the same time as
animals we would readily recognize as scorpions were already
wielding their lethal venom, which has so effectively ensured their
survival. If they had been able somehow to travel through time
and scuttle out of the rock they would have left familiar tracks,
alongside those of their living descendants. As I sat on a low bluff
in the Huqf glowing in the midday heat I became acutely aware
of time past, time present, and time defied.

Our measurements were successful. We found that the size of

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TIME

the trilobites was within the size range of the tracks; and genal
spines on the edge of the head of the trilobite were consistent
with grooves cut to either side of the digging marks in the furrow.
Dolf pointed out to me that this particular trilobite seemed to
forage by making tracks with a circular compass - rather like the
handsweeps of a window cleaner. The track even had a name,
Cruziana semiplicata, which had been given to it more than a
century earlier by 'the English Barrande', John Salter. This trace
fossil had originally been found in Upper Cambrian rocks in
North Wales, near Merioneth, in wild, wet, mountainous country
as different from the Huqf as is possible to imagine. The finishing
touch for our theory was that the very trilobite we had fingered
as the culprit from Oman has recently been recognized from
rocks not far from Salter's original tracks in North Wales. Maybe
we are getting as close to a particular moment of trilobitic time
as we ever should: one scrape of a limb, one flick of a hair.

Then there is geological time.

Geological time is calibrated in millions of years, but it can also
be calibrated in trilobites. Because they evolved rapidly, trilobites
provide a chronometer - a timepiece of personalities. We recog-
nize the faces of trilobites in the same way a skilled numismatist
might recognize portraits of minor Roman emperors from a new
excavation.

The range through geological time of a species of trilobite is
as characteristic as that of King Tutankhamun through historic
time. In practice, an investigator hopes to find a whole fossil
fauna so that he may cross-check one species with another. I
never cease to wonder at how well the stratigraphical system
works. My visit to Oman revealed a late Cambrian date for the
rocks within a few hours of my arrival. On another pioneering
expedition to Thailand I was able to recognize the Ordovician
age of some trilobite limestones by comparing their species with
those known from China for decades previously - even though
the rocks had previously been mapped as Silurian on the geologi-

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trilobite!

cal maps of southern Thailand. These identifications were based
on the works of a hundred minor Barrandes - indeed, one of
the species from Thailand was first named by one of his Czech
contemporaries. Knowledge is cumulative, and hard won. It
would be tedious in the extreme to name all the names and pile
them in geological order in a great inventory of trUobitic time.
There are so many trilobites, and more being added to the list
all the time, that a human lifetime is inadequate to know them
all. Even after twenty-five years of study there are still parts of
the geological column to which I am a stranger. But while geol-
ogists and palaeontologists strive for ever greater precision it
is still possible to make a grand sweep through geological
time to see the ebb and flow of the trilobites, as one replaced
another.

In the Lower Cambrian 540 million years ago a variety of
trilobites appeared quite rapidly. Those with long, narrow and
often tapering glabellas are typical. In North America Olenellus
and its many allies were abundant, sharing long thoraces with
many segments and minute pygidia, often wdth a very narrow
part at the back end behind a particularly large thoracic segment.
The long eyes appear to run continuously into the glabella, but
there were no moulting sutures on the upper surface of the head.
In China, and through much of the Near East, a range of generally
similar animals did have facial sutures - Redlichia is one of the
most widespread. I collected fragments of this genus on a relent-
lessly hot rocky slope in Queensland, Australia, reflecting at the
time that this would be the nearest I would ever get to roast
trilobite. The Chinese divide their rocks into fine time slices using
different forms of these animals as indices. In rocks of similar
age appear the first miniature trilobites, such as Pagetia, which I
regard as primitive relatives of Agnostus. Some of these diminutive
forms - usually about the size of a smafl woodlouse - have
inconspicuous eyes, and three thoracic segments; others are blind
and with two, like agnostids. They carry on into the Middle
Cambrian, by which time true, blind agnostids are often abund-

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TIME

ant. All these small trilobites are outstandingly usefUl for dating
rocks, since some species are very widespread and they evolved
quickly into other species. If they were indeed planktonic, this
might account for their ubiquity. They are tiny timepieces, and
as precisely engineered, for they enroll into perfect little capsules,
and every bit of the skeleton collaborates in their protective stance.
Alongside a variety of agnostids Middle Cambrian rocks yield
giants like Paradoxides, which certainly stalked the sea-floor rather
than cruising far above it. Trilobites of this type also provide
useful chronometers: if you can recognize Paradoxides, you can
recognize the Middle Cambrian. There were trilobites of usual
size, too, some of them blind, like Meneviella. Several of these
blind trilobites were known already to Joachim Barrande more
than a century ago, and their discovery from rocks in France,
Wales and Spain provided an early proof of the affinity of time
and trilobite; they could evidently be used to date rocks! Their
relatives had normal eyes, so it is likely that these trilobites became
blind, rather than being blind from their evolutionary birth. They
lived in deep, or at least turbid seas. Their oculated kin include
Ptychoparia striata, a species known from wonderful material in
Bohemia. It is, you might say, a Joe Average kind of trilobite,
with a moderately small pygidium and a somewhat tapering gla-
bella with medium-sized eyes, and fairly numerous thoracic seg-
ments: nothing exaggerated in any direction. The commonest of
'rock shop' Cambrian trilobites, Elrathia kingi, is a North Ameri-
can equivalent, smaller and wider, perhaps, but just as middle-of-
the-road. There are many dozens of broadly similar trilobites, the
naming of which causes even the most patient of specialists to
gnash their teeth. Their correct determination requires skill and
experience, for many similar-looking beasts range through Middle
and Upper Cambrian strata. It is much easier to recognize some
of the spiny trilobites which appear among the Middle Cambrian
faunas, the first of many imitations of pincushions in trilobite
history. Trilobites with rather large pygidia became common at
the same time. Most conspicuous among these are Corynexochus

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TRILOBITE

Fieldaspis, 6cm long, a typical Middle Cam-
brian trilobite from British Columbia, Canada.

and its allies (see Fieldaspis, above), a distinctive set of trilobites
with long, forwardly-expanding glabellas shaped like pestles, often
with spiny thoraces and distinctive hypostomes. The Middle Cam-
brian was a rich time for trilobites, and when you remember that
there were many additional kinds of arthropods in the Burgess
Shale, it might be appropriate to dub the Cambrian the 'Age of
Jointed Legs': it was probably the time when scrabbling limbs
were at the acme of design.

Agnostids and many others carried on into the Upper Cam-
brian. Peculiar trilobites, more or less related to Damesella (see
Drepanura, p. 233), are found in strata of this age in China:

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TIME

they all have tails with different arrangements of marginal spines,
looking like combs or strange agricultural instruments. One of
them - featured in Chinese medicine as the 'swallow stone' -
was ground down and incorporated into potions. Most Chinese
remedies I have come across are said to be good for old age, and
it seems conceivable that this most ancient of medicines was a
case of sympathetic magic. Their appearance in the pharmaco-
poeia made Drepanura (see p. 233) one of the earliest Chinese
trilobites known in the West. Related species extend into Aus-
tralia, where the distinguished Estonian emigre Alexander Armin
Opik described a whole range of special trilobites retrieved from
among the prickly spinifex bushes in central Queensland. His
North American equivalent is Alison R. Palmer, known to all
trilobitologists as 'Pete', one of those people to whom the over-
worked epithet 'indefatigable' truly applies. His works on the
Great Basin - that vast area of Basin and Range embracing much
of Utah and Nevada - are a tribute to mind and hammer over
matter. I have climbed some of the same slopes, at an elevation
which leaves you gasping. If you are not careful you can slide off
on a scree slope all the way back down the way you came. The
air is fragrant with conifer resin. Opuntia cacti snag you unawares
and there is the occasional startling buzz of a rattlesnake, but
mostly this is benign, if hot, country, and from Pete's slopes you
can see sagebrush stands in the basins dotted with a few cows,
and at the lowest point maybe the glistening white of a salt pan.
Pete collected all the rocks that crop out on the range-sides, where
the trilobites provided another narrative of late Cambrian time,
hundreds of different species teased out from the flat-bedded
limestones and shales, telling a story of evolutionary radiations
and local extinctions. Pete knows every particular of these animals
with the kind of relentless enthusiasm that is a distinguishing
characteristic of many American intellectuals, and no doubt one
of the reasons why they have so conquered the world.

Around the edge of the North American continent, and in
Scandinavia, as well as in Wales, the late Cambrian strata yield

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TRILOBITE

up different trilobites, Olenidae, which I have already celebrated
in Chapter 7. They preferred a specialized habitat, low in oxygen.
Geological episodes as short as half a million years can be recog-
nized using these trilobites as timepieces. This may not seem like
precision, compared with 4.39 am on 15 August 1931, but 500
million years ago it is precision to one part in a thousand. In
time, precision is relative.

Ordovician time was probably when trilobites lived in the most
places and occupied the most varied ecological niches in the sea.
They lived everywhere from the shallowest sands to the deepest-
water shales; in sunlit reefs and in gloomy abysses. Some Cam-
brian families survived, like Olenidae and agnostids, but what
gives the Ordovician its special flavour is the appearance of a
whole range of trilobites that formed the foundations of the
subsequent history of the whole group: cheirurids, odontopleur-
ids, proetids, calymenids, encrinurids, lichids, phacopids, dalman-
atids - the list goes on. I might apologize for giving such a litany
of families (typical generic examples of most of them have already
been mentioned in this book) were it not also an almanac of
Ordovician and later times. A familiarity with a few dozen of
these animals will help you peg down time, give you a chronology
for the splitting of continents or the appearance of the first scor-
pion. The names themselves really do matter. Most diagnostic of
Ordovician strata are trilobites that did not survive into the Silur-
ian. These include the free-swimming trilobites like Cydopyge and
Carolinites; while on the sea floor thrived many asaphid relatives
of Lhywd's Ogygiocarella, together with exquisite trinucleids, and
lance-bearing relatives of Ampyx. There were trilobites as spiky
as porcupines and as smooth as boiled eggs; trilobites larger than
lobsters and smaller than gnats. Because the continents were dis-
persed at the time there were different trilobites on separate
continents - and each one with a chronological narrative of its
own. The reader might begin to understand the sense of awe that
a researcher feels at the magnitude of her task as she makes a
bid to know them all.

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TIME

Elrathia, a typical mid-
Cambrian trilobite a few
centimetres along at most,
with a 'flower-pot' glabella,
thirteen thoracic segments
and a moderately small
pygidium. There are hun-
dreds of basically similar
trilobites. this specimen is
from Utah, western USA.

The tail of Drepanura, the
'swallow stone' from the
Cambrian limestones of
Shandong, China.

At the end of the Ordovician there was a major, or mass,
extinction, one of the most important such events in the whole
history of Hfe. A great glaciation centred on North Africa
undoubtedly drastically cooled the climate in later Ordovician
times, and this was probably the main cause of the faunal crisis.
You can find the kind of deposits associated with ice ages in

233

trilobite!

Africa and elsewhere - and, remarkably, trilobites quite close by.
A few species were evidently tolerant of the cold, and one of
these, Mucronaspis, spread very widely in the cool era. It was one
of the trilobites I collected in Thailand, and it was with no litde
astonishment that I identified it there with a species originally
described from Scandinavia. Trilobite time really works across
the world! There was a big loss of families at the end of the
Ordovician, and several of those that died out - like agnostids -
had a history going back to the Cambrian. Some of my favourite
trilobites were among the casualties: no more Trinucleus, no more
Isotelus. I doubt whether any free-swimming species ever reap-
peared. The trilobitic world after the Ordovician was a different
one. But the survivors among the trilobites soon bounced back,
and by the middle of the Silurian these remaining families had
diversified mightily. A little practice allows the student to recog-
nize Silurian Balizoma, Calymene, Proetus or Ktenoura. They are
still common enough to function as useful chronometers.

There is much less distinction between early Devonian trilobites
and those of the Silurian than there was between those of the
Cambrian and Ordovician, or between Ordovician and Silurian.
The Devonian was the apotheosis of Phacops and its relatives: for
a while the schizochroal eyes had command. There was also a
remarkable variety of spiny trilobites. In some localities, particu-
larly in present-day Morocco, it seems that almost every Devonian
trilobite became covered in prickles and spikes. Just a week before
writing these words I saw an unnamed trilobite which carried a
great trident sprouting from its glabella, an adaptation as unique
as it is inexplicable (see p. 253). Find it again and you would
know exactly with which moment of geological time you were
concerned. Otherwise, the trilobite was not so exceptional, just
another relative of Dalmanites. Then there are species with great,
curled ramshorns originating at the neck as shown in the next
figure, or intimidating batteries of vertical spikes. Some trilobites
related to Lichas decorated themselves with the splendour of a
medieval pope; other odontopleurids - always spinulose from

234

TIME

Dicranurus, a spiny relative of Odontopleura from tlie Devonian of Morocco.
Life size. See cover.

their Ordovician origins - transformed into little more than
bunches of needles. Even the zoologist hardened by decades of
exposure to Nature's curiosities whistles through his teeth when
he sees these animals for the first time. Such armour was, no
question, protective. Was there some new threat which prompted
such an exuberance of spinosity? Could it be connected with the
rise of jawed fish at about the same time? As with all such apparent
correlations, it is very hard to know whether a particular observa-
tion unequivocally leads to the truth. There is usually some

235

trilobite!

alternative explanation waiting in the wings. For an appraisal of
time, we do not even need to know why: we can treat the bizarre
trilobites as one might curious statues or totems from a lost
culture, they typify particular moments, they fix the past.

Nearly all these fantastical trilobites failed to survive the
Devonian, for later in this period there were a series of extinction
events which picked off one after another of the trilobite families.
The greatest of these events was the latest, the Frasnian-
Famennian event. Very few trilobites survived: even the phacopids
were doomed. Those that did survive were all related to one of
the less spectacular trilobite groups of the Devonian fauna: Proetus
and its relatives. Small and compact, they mostly eschewed the
spinose extravagances of their contemporaries. Some of them had
knobbly heads, but that was about as adventurous as they became
before the Carboniferous. By then, time was written wholly in
variations of proetoids. My friend Bob Owens will extol their
varied subtleties; Gerhard and Renate Hahn are German pro-
fessors who know every nuance of these trilobites. And it is true
that in the earlier Carboniferous, while tropical seas flooded much
of Europe, the proetoids produced many different designs. Some
of them resembled trilobites ft-om older periods, probably because
they adopted similar life habits. There were blind inhabitants of
deep waters; in crystalline limestones we find animals that an
unwary observer might mistake for Phacops; there were even
some that look like Ordovician Harpes. However, solid-looking,
compact, big-eyed, but still smallish trilobites like Griffithides were
probably the commonest type. My belief is that, far from being
in decline, trilobites kept their capacity for invention, reinvading
old habitats, and spreading back into deep water. New forms
evolved so fast that they are still useful in characterizing chunks
of geological time, although it would take an optimist to claim
that they were as common in Carboniferous rock outcrops as
they were in Silurian ones. Hardy's hero would have been more
likely to have had a trilobitic encounter had he dangled from an
Ordovician precipice. Clearly, their realm was shrinking; and

236

TIME

more so in the succeeding Permian. A few famous localities in
Sicily and Timor show that in places we might still have seen a
heaving mass of trilobitic bodies had we waded through the shal-
lows there 250 million years ago. New genera stUl appeared, so
that even close to their end trilobites were still capable of ticking
off geological time. But then, after calibrating time for a period
three times as long as the dinosaurs, the trilobite chonometer
stopped.

I should not give the impression that this great temporal story
was easily read, as if one massive and continuous pile of strata
had yielded one trilobite after another, plucked in order. There
are few areas that can be read that simply; it was more a question
of pasting together the timescale from snatches of narrative, here
and there. There were mistakes and there were arguments, some
of them virulent. Even the great Charles Walcott erred. In 1883
he wrote, in his dry fashion: 'Below the Potsdam Sandstone [a
formation in Nevada] there occurs a distinct fauna, characterized
by a considerable development of the trilobite genus Olenellus, a
genus that in the embryonic development of several of its species
proves that it is derived from the Paradoxides family and is conse-
quently of later date.' Paradoxides you will remember as a Middle
Cambrian guide, while Olenellus was a Lower Cambrian index;
he had them the wrong way round. Walcott had evidently con-
fused two of the categories of time I have considered in this
chapter: development time of the individual, and geological time.
He had plausibly observed that smaller Olenellus look rather like
Paradoxides, but what we now know of heterochrony - time
shifts in development - allows us a different explanation. The
similarities are only the result of an ultimate common ancestry.
Beware assumptions about time, for the rocks will put you right.
And this is what happened to Walcott a few years later, when the
Scandinavian geologist W. C. Brogger proved that rocks carrying
Olenellus-Vike animals in Norway were clearly overlain by Para-
doxides. He had found them preserved as consecutive narrative
pages, in an undisturbed rock sequence. Walcott, like his friend

237

trilobite!

G. F. Matthew - who worked in folded rocks in New Brunswick
where the evidence was ambiguous - had to re-examine the evi-
dence and, Hke the good scientist he was, he allowed the facts to
change his view. He did not persist in attempts to twist time to
fit his own preconceptions.

Arguments about the timescale will not stop; as knowledge
grows, so the arguments become focused on ever smaller intervals.
I have spent much of my scientific life observing slow progress
towards an international agreement on how to define the boun-
dary between the Cambrian and Ordovician, a process in which
trilobite timepieces have played a part. Esoteric though this prob-
lem may seem, I have seen grown men glow incandescent with
rage over this metaphorical millisecond in life's history. Candi-
dates for the place to define this time boundary at a particular
point in a rock section have been proposed at various locations
in Newfoundland, and in Utah, in China and in Norway - I have
visited them all.

In China, near a small town called Changshan, I came face to
face with another manifestation of time. Our party was investigat-
ing rock sections which spanned the contentious boundary, col-
lecting trilobites from the critical interval while sitting on a warm
hillside, happy as a lark (probably happier). From time to time,
huge buzzing things flew past - I was rapt enough hardly to
notice them. Suddenly, I felt a searing pain in my side. One of
the giant insects had crawled up inside my field jacket, where it
had doubtless been chafed and irritated by my vigorous hammer-
ing. I leaped to my feet, and the largest hornet I have ever seen
in my life fell to the earth. It was a mystery how a creature so
enormous and filled with venom could manage to get off the
ground, let alone fly around the place. As the pain intensified I
attempted to interest our interpreter in the urgency of my case.
As she didn't know the word 'hornet' I flapped my hands and
buzzed, doing a dramatic stinging motion into my side. 'Ah,' she
said, smiling warmly, 'bee! Not very derangerous!' By now the
paddy fields were swimming before my eyes. Luckily my friend

238

TIME

David Bruton had seen the whole thing, and eventually made it
clear to our hosts that it was one of the flying monsters that had
pierced my abdomen. A very strong American called Jim Miller
then carried me delicately along the narrow earth dykes that
separated the paddies, winding in a kind of rectangular confusion
hither and thither. To escape to the road is an intelligence test.
In a moment of lucidity I recall staring from Jim's back into a
small pond full of water-chestnut plants, and thinking: 'my time
has come.' This, my own personal time, had apparently run out
in the middle of China in pursuit of a problem of interest to me
and a few dozen others. This was my connection with the search
for another moment 489 million years earlier. For a moment, I
understood my insignificance in the face of geological time.

Fortunately, I made it to the field vehicle, which carried me
rapidly to Changshan. The appearance of a westerner in this
remote town in the early 1980s was something of a sensation, and
the whole place turned out to follow my prostrate body to the
'hospital' - which turned out to be a simple building with no
glazing in the windows. Several dozen heads craned through the
window for a good view. They were having the time of their
lives. I remember little, but I am told that the now tumid swelling
was cut with a sterilized knife and squeezed enthusiastically,
resulting in satisfactory gouts of blood. A poultice of mashed-up
vegetables was then applied. Nodding confidently, my doctor
said, through the interpreter: 'Here, we use a combination of
traditional Chinese and Western medicine.' I was given an aspirin
(that was the Western part), and a vast phial of big pills made
from weeds (the Chinese part). They worked, for in two days I
was up and about. Curiously, the incident caused me a certain
loss of face. The famous old Chinese Professor Lu Yen-hao said
to me when I had recovered: 'I have seen these insects many
times, but you are the first person bitten.' Then, having thought
for a moment, he added: 'except maybe some peasants.' When I
returned to London I told the hornet specialist in the Natural
History Museum of my experience. 'Wish you'd brought back

239

TRILOBITE

the bloody hornet,' he said. 'I don't think we've got one of those
in our collections.'

Science depends on honest reporting. It would not matter greatly
if any of the items in the previous story were exaggerated, or
even if part of the account was made up for the amusement of my
readers - although I should reassure you that I recall everything as
clearly as I can. But what no scientist is allowed is deliberately
to mislead. It is worse if this deception is in the service of self-
aggrandisement. This was apparently the case in the 'affaire
Depraf.

Jacques Deprat was a young geologist employed by the Service
Geologique de I'lndochine in the early years of the twentieth
century, at the time when what is now Vietnam was a French
colony. This was an heroic period for geological exploration. The
scientific method had unravelled many of the complexities of the
Alps and the Himalaya; indeed, it seemed as if the whole structure
of the Earth might be within the grasp of a mind sufficiently
bold. Exploration of hitherto unknown territories was a central
part of this quest. Jacques Deprat was, without question, a talented
and courageous geologist of great energy. He was an accomplished
alpinist who revelled in collecting information fi-om inaccessible
peaks; a synthesizer with a gift for reconstruction of complex
rock structures in three dimensions; and a palaeontologist of
some ability to boot. Generalists of this kind are virtually
unknown today. He was also somebody who had pulled himselt
up from modestly bourgeois beginnings by virtue of talent and
hard work: a hero for our times, one might say. This was no
small achievement in a France that was class-ridden and elitist.
To make his reputation, Deprat had been compelled to find work
at the edge of the French empire, and even there those who
occupied establishment positions - all, like his nemesis and
superior officer Honore Lantenois, products of the French elite
education system - despised outsiders. But by 1912 Deprat had a
worldwide reputation; his relentless hard work in the field had

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TIME

shown that structures recognized in Europe could be applied to
folded and thrust rocks in Indochina, and, most remarkably, that
rocks of Ordovician age could be reliably dated from this remote
area by the trilobites they contained. They included species named
for the first time by Joachim Barrande from the strata around
Prague: and what better evidence than species described by the
greatest time-keeper of them all? These species are known today
as Deanaspis goldfussi, Dalmanitina socialis and Dionide formosa.
The first two named are famihar fossils from the late Ordovician
Letna Formation in Bohemia, where they are particularly
common trilobites; most old collections have examples tucked
away in the back of a drawer. Dionide formosa is a somewhat rarer
form from the Vinice Formation, but well-known nonetheless. It
was evident that these reliable, old-established trilobite chron-
ometers were capable of wide distribution. The formal descrip-
tions of the specimens from Vietnam were made by Deprat's
colleague, the in-house palaeontologist Henri Mansuy, in papers
published by the Service Geologique in 1912 and 1913. Deprat's
reputation seemed to be unassailable.

But then the doubts began. Mansuy began to treat Deprat with
caution. Lantenois went further: he asserted that the fossils of
goldfussi and socialis were indeed what they were supposed to be,
but entirely because they were, in fact, Bohemian specimens
falsely claimed as coming from the locality of Nui-Nga-Ma, near
Vinh, in Indochina. They were 'plants', falsehoods, cheats; at the
very least, to use the delicate word employed by Jean-Louis Henry
in his 1994 account of V affaire, they were 'apocryphal' - of doubt-
ful authenticity. If correctly identified, such duplicity broke the
golden rule of honest science. Deprat defended himself vigorously,
and pooh-poohed the charges as slander. He may have accurately
intuited that the less able, if better connected, Honore Lantenois
resented the rise of this upstart in the geological firmament. After
all, it was he, Lantenois, that had placed the Service Geologique
de I'lndochine on a firm scientific footing, but Deprat had had
much of the glory. Never underestimate the power of bile. But

241

trilobite!

as one official investigation gave v^^ay to another tribunal, as the
Societe Geologique de France became involved, and the great
voices of the day were called upon for their opinions, things
looked bleaker and bleaker for Deprat. An official expedition to
Nui-Nga-Ma which had been convened to duplicate his findings
yielded nothing definitive. Deprat refused to make his field
notebooks available to the Commission of Inquiry, behaviour
which was decidedly incriminating. Even while tens of thousands
of young Frenchmen were being slaughtered in the trenches
French justice ground slowly onwards - for the colonial world
of Indochina was in another realm of time. Letters took many
weeks to arrive by sea, to deliver the latest instalment of justice
from the mother country. Time was accelerated for the dying,
while Deprat's pursuit by Lantenois was conducted in slow
motion, at a distance. Finally, Jacques Deprat was disgraced,
demolished by the same geologists who had once built him up.
Professor Termier, his one-time champion and doyen of Parisian
geological society, was the reluctant executioner of his reputation.
A grand commission of the celebrated Societe Geologique de
France concurred that the trilobites from Nui-Ng-Ma were apoc-
ryphal. Those who had once praised the young Deprat were now
the buriers of his reputation. In November 1920 he was dismissed.
You must not lie about trilobites, nor yet about time. Falsehoods
will find you out.

Except that the obliteration of his reputation did not happen
- quite. Jacques Deprat wrote an account of the whole business,
after a period in retreat licking his wounds. He wrote it as a
roman a clef under the title Les Chiens abouient (The baying
hounds), and there you might find - little disguised - the story
of his arrival in Vietnam, of his relationships with Lantenois and
Mansuy, and a recitation of his downfall. Of course, it is a
partial account, but it does have some ring of truth. It is imposs-
ible for the modern reader not to sympathize with the outsider,
tarred by an intolerant and privileged establishment. In 1990, M.
Durand-Delga made a bold attempt to rehabilitate Deprat at a

242

TIME

special session of the Societe Geologique de France, apparently
accepting the notion that he was 'set up' by those jealous of his
reputation. This was the eventual defence that Deprat himself
adopted (after changing his mind several times). It makes a good,
contemporary, psychological thriller. Nor is there any doubt
about Deprat's real achievements in other spheres of geological
science. And what other scientist, so vilified, might have the talent
to play novelist?

But the question remains: did he or didn't he? It scarcely seems
possible that Henri Mansuy, elsewhere an exemplary palaeontol-
ogist, would in this case relax his standards of probity out of
pique. Besides, it was Deprat himself who photographed the con-
tentious cranidium of Deanaspis goldfussi, published in 1913. And
if he was innocent why did he collude with the suspicions of his
enemies by refusing access to his field notebooks? Equally, one
might wonder why, since his career was in the ascendant, he
should endanger it by so foolish a deception. Was he revelling
in a feeling of omniscience? Did he feel so inecure that he must
embroider the truth to make it more appealing to the world?
Whatever the answer, Deprat was ruined as a geologist.

Several years later Deprat resurfaced in another Hfe under the
new name of Herbert Wild, novelist. It was Herbert Wild who
wrote Les Chiens abouient, and an intelligent observer might have
readily made the connection between Wild and Deprat. He
enjoyed critical success with several subsequent novels, one of
which was nominated for the Prix Goncourt, and earned a suf-
ficient living from his pen to support his family. He also returned
to his first love, the mountains, and became a considerable
alpinist, a master of the Pyrenees, and pioneer of several of the
more challenging peaks. So far as we know, he never wrote about
geology again. The mountains eventually claimed his life in March
1935; curiously, he had written a novel which described in some
detail the circumstances of the fall in which he subsequently died.
Only upon his death was the connection between Wild and Deprat
finally revealed.

243

trilobite!

There is an intriguing symmetry between this story and the
one with which this book began - the episode in A Pair of Blue
Eyes. Both concern fictional trilobites. Hardy's danghng hero
faced death reflected in the eyes of a trilobite; a fall killed Deprat,
after trilobites had ruined him. In Hardy's case a plausible fiction,
a Carboniferous Cornish trilobite, was used for dramatic purposes
by a novelist whose reputation is probably as high now as it has
ever been. No one would claim that his fame is undeserved merely
because the trilobite was a creature of his imagination: it is the
novelist's job to whip up such fancies. Deprat was disgraced
because his fictions were created under a diffierent convention;
he was supposed to follow the rules of the scientific method.
However we may empathize with the tragedy of brilliance wasted,
or recoil at the vindictiveness of his persecutor, Lantenois, we
know that the whole scientific endeavour depends on not doing
what Deprat is alleged to have done. There is no possible compro-
mise on this principle: no scientist can be trusted who tells the
truth 78 per cent of the time. How do we recognize the flawed
percentage? By an exquisite twist, Deprat became a novelist, and
one who may even have admired the works of Thomas Hardy.
If, as Mr Wild, he had called upon trilobites to play a fictitious
role it would have passed unremarked. The difference between
the creative roles of science and art could scarcely be better delin-
eated than in this Tale of Two Trilobites. The distinction is this:
like all artists. Hardy made his own time - the compass of the
novel has its own bounds which the reader volunteers to enter
when she engages with the book. The veracity of the trilobite is
incidental, just as it matters not a whit that Hardy thought of
the creature as a stony crustacean. By contrast, Deprat's avowal
of time was an oath taken on the credo first laid out explicitly
by Francis Bacon in Novum Organum (1620):

But if any human being earnestly desire to push on to
new discoveries instead of just retaining and using the
old; to win victories over Nature as a worker rather than

244

TIME

over hostile critics as a disputant; to attain, in fact, clear
and demonstrative knowledge instead of attractive and
probable theory; we invite him as a true son of Science
to join our ranks.

He who abuses the call to 'clear and demonstrative knowledge'
by the employment of deception is no 'true son of Science'.
Imagination may provide the source from which both artistic
and scientific genius flow, but the artist delights in fabrication,
just as the scientist revels in discovery. Time tests the quality
of the artist's vision, just as it tests the durability of scientific
revelation.

245

X

Eyes to See

Most scientists work in small arenas. To look at popular accounts
of scientific discovery you would think that every man or woman
in a white coat was seeking to solve the problems of Unified
Field Theory, determine the genetic basis of cancer, or concoct
a neurological theory of consciousness. There are a thousand
fields of scientific endeavour, and very few hit the combination
of timeliness and innovation that generate Nobel Prizes (or 'the
trip to Stockholm', as I overheard one eminent Fellow of the
Royal Society describe it). But scientific work is interconnected:
like a spider's web, it is sensitive to movement in any part of the
structure, and interlinking strands give it its strength. Trilobites,
too, connect to large scientific issues: how species are born and
die; the 'explosive' nature (or not) of the Cambrian; how the
biological world we know was engendered; how the ancient conti-
nents lay. It is perfectly possible for a researcher to labour for
many years, known only to a dozen or so of her colleagues,
maintained by love of what she does. Then, by making some
connection, she may suddenly be at the cutting edge, lauded by
laureates, praised by prize-givers. As in the parables (not to men-
tion the trilobites), those that have eyes to see, they will see.
Ruth and Bill Dewel, biology professors from a small east coast
American university, were almost alone in their enthusiasm for
tiny, stumpy-legged tardigrades, ubiquitous creatures beneath

246

EYES TO SEE

every clump of moss, that may be close to the ancestral arthro-
pods. The realization that some early Cambrian fossils may relate
to them in important features of the head, and the development
of molecular methods for determining their evolutionary relation-
ships, propelled these little organisms from peripheral to pivotal.
The Dewels' years of patient observation were suddenly germane
to all kinds of big questions in the evolution of the most species-
rich animals known - the arthropods, in their exuberant variety.
The beauty of the scientific life is that every honest practitioner
may add a permanent contribution to the edifice of knowledge.
They may be remembered by few of their intellectual successors,
but their contribution counts, even if it is anonymous. It is not
necessary to be one of the famous few to make a permanent impact.
I know that not one person in ten thousand (outside Prague) has
heard of the great Bohemian palaeontologist Joachim Barrande,
and he is a considerable figure in the trilobite firmament. No mat-
ter: his monument survives in the geological maps of his homeland
and the very fabric of geological time. The scholar will soon find, if
he digs a little further, the name of Barrande attached to a hundred
scientific names of important fossil animals. Then he will discover
that Barrande, too, made mistakes, most notably a theory for the
successive origin of animals from his home area of Bohemia, based
upon a mis-correlation of rocks. No matter: the errors are not
incorporated into the fabric of the edifice of knowledge. Rather,
they provide the stuff for historians to chew over, as they trace the
complex progression of ideas from conception to acceptance. In
the end, the investigator will discover Joachim Barrande the man,
the fussy perfectionist who devoted his life to making known the
riches of the Bohemian Palaeozoic rocks to the world, and who
named a clam for his housekeeper. Like Marcel Proust, whose neur-
asthenic obsession crafted one of the greatest and longest of all
novels, Barrande devoted his life to his vision, and it was a grand
one. Like Proust, Barrande lived in an urban apartment cared for by
a strong-minded servant. Science is, at root, another human activity
shot through with all the frailties and eccentricities that being

247

trilobite!

human entails. Scientists' life stories are like other life stories, and
it is just as much fun gossiping about the details. But, for the edifice
of truth, it does not matter whether Barrande was saint or sinner,
transvestite or transubstantiationist, so long as he was honest.

It may be access to a kind of immortality, of however unusual
a variety, which makes science such an attractive option for intelli-
gent people seeking meaning in their lives. In our secular age,
other promises of continued existence posf- mortem have lost their
persuasiveness. If moral virtue must too often be its own reward,
scientific virtue carries the promise of a reward of permanence, of
making a difference. At its most blatant the permanence resides in
a label, a discovery or an idea married forever to the name of the
discoverer: Creutzfeldt-Jakob Disease, Asperger's Syndrome, Hei-
senberg's Uncertainty Principle, Halley's Comet. In biology or
palaeontology the author is for ever tied to a species he described
and named for the first time: the trilobites Illaenus katzeri Barrande,
or Balnibarbi erugata Fortey allow us both this small measure of
immortality. The reward in other branches of science is similar, if
more subtle. Death cannot be cheated, but the discoveries made in
one's prime might well outlive bodily decay.

I find that the creative part of the scientific process can be
explained rather clearly at the trilobite scale. The pursuit of
nuclear physics or physiology employs thousands of scientists.
Advances are made which cause regular revolutions in under-
standing. I am told that nearly all the articles in journals in
these fields become obsolete before a decade is up. Workers
find it difficult to keep abreast of current discoveries, let alone
embrace the fullness of their past. History tends to be jettisoned
in favour of keeping up wdth the pack. At the same time, it is
necessary to focus on only a small part of the field, especially
because the problems faced tend to be both highly technical
and in very competitive areas of advance. Take your eye off
the ball for a moment and somebody else will snatch it! The trilo-
bite time scale, by contrast, allows us the leisure to survey the
whole of history. We find it easy to connect with Dr Lhwyd in

248

EYES TO SEE

the seventeenth century, with Linnaeus' contemporaries in the
eighteenth century, or with Walcott and Barrande in the nine-
teenth century. The discoveries of the last hundred years exist in
continuity with the past: not seamlessly, for progress is almost
always by fits and starts. But Harry Whittington's discoveries
about trilobite larvae are clearly built on those of his predecessors,
like Sir James Stubblefield or Professor Beecher. We are constantly
in touch with our past; and libraries are where we do honour to
those who came before us. Our literature never really goes out
of date. Though trilobites might lie far to one side of the web of
scientific knowledge, they feel the same movements, and respond
to the same stimuH, as do scientific disciplines far closer to the
centre. This history shows that the past, too, is mutable; and that
when new discoveries are made, we re-write historical 'facts'. The
job of the palaeontologist is to reinvent the past. There could be
no task more demanding of the scientific imagination.

Some people still believe that science and the arts are somehow
opposed - the former dissective, the latter creative. This is the
attitude famously encapsulated in the 1950s phrase 'The Two
Cultures', which was coined by C. P. Snow, novelist and senior
civil servant. Snow's synopsis has a far longer pedigree, going
back at least to the mystic, poet and artist William Blake, and to
those who opposed the experimentalist approach advocated by
the Royal Society in England in the eighteenth century, and by
other academies in the western world. The artist, it was implied,
plumbs greater truths through his imaginative fabrications than
the obsessed reductionist, who seeks to explore the secrets of the
butterfly by dismantling its wings. The critic's stance is perfectly
expressed in this verse by Edgar Allan Poe:

Science! true daughter of Old Time thou art!
Who alterest all things with thy peering eyes.
Why preyest thou thus upon the poet's heart,
Vulture, whose wings are dull realities?

249

trilobite!

Palaeontology is a 'daughter of Old Time', or it is nothing. And
throughout this book I have used the image of their own 'peering
eyes' as the key to understanding the trilobites' world, just as I
have consciously linked this image with the observations made
by scientists upon the fossil material they wish to bring back to
life: eye gazing on eye, unblinking. We peer, therefore we learn.
But I regard everything I have described as raw material for the
poet. Even the smallest item of scientific revelation can be a
matter for joy, and a truth unearthed glitters with the iridescence
of a tropical Papilio butterfly.

So why are so many people ambivalent towards science and
scientists? Several images of the scientist come to mind. First,
there is a stereotype of a kind promulgated by TV advertisements,
which I might term the 'barmy boffin'. Bald of pate, but fuzzy
above the ears, and with enough facial tics to keep horseflies at
bay, the boffin whizzes around in a state of high excitement over
his latest discovery - often a gizmo of arcane purpose. The boffin's
jacket is a baggy tweed affair with screwdrivers poking out of the
breast pocket. The boffin always has thick glasses: for some reason
it is de rigueur to be short-sighted - and indeed, there is apparently
a statistical connection between myopia and intelligence. Boffins
always have rather feeble physiques. There is a curious assumption
that the development of the brain drains away muscular develop-
ment. It is as if the brain itself were regarded as a kind of parasite
that feeds upon the rest of the body: as the cranium expands so
the biceps and pectorals shrink, until I suppose the perfect boffin
is a massive brain perched atop spindly limbs, like some kind of
stick insect crowned with a calculator. Professor Calculus, in the
books about Tintin, the boy detective, was the type example of
the boffin: clever as you like, but always vaguely discombobulated,
and needing down-to-earth common sense to make a fist of
anything. His inventions were always liable to take off with a
disastrous life of their own. However, nobody was ever in doubt
that Professor Calculus's heart was in the right place. No spoiler
of other people's pleasures, his inventions were always somehow

250

EYES TO SEE

linked to something magical - gadgets which might bring the
impossible into unpredictable existence. Nowadays, the boffin's
equivalent is probably more the intense computer nerd, playing
with his machines with the abandoned assurance of the concert
pianist. Out of this electonic mastery comes - a beautiful android?
a time machine?

But Poe's* scientist is somebody altogether more sinister, a
heartless dissecter of innocent animals, perhaps, or a genetic
engineer, or a tinkerer with anatomy along the lines of The Island
of Dr Moreau. H. G. Wells's story has provided the screenplay
for several films; the eponymous Doctor peoples his island with
ghastly inter-species grafts. As with much of Wells, what once
seemed perverse imagination now seems almost possible, but
somehow less sinister. We no longer believe that the implanted
heart of a pig might convert the recipient to piggishness. But
Wells may have contributed something to the demonization of
the scientist by pointing up what happens when technical facility
is decoupled ft"om moral responsibility. After all, in the mid-
twentieth century we have had examples in the Nazi era which
exceeded Wells's most oppressive nightmares. A perpetrator of
these aberrations can scarcely be the 'vulture whose wings are
dull realities' of Poe's poem, for there is a much more active
malevolence here than provided by an opportunist scavenger.
Both the benign and the intimidating images of the scientist
reflect the ambiguity of the role as the layman sees it. On the
one hand many people look to the scientist as cure-all, purveyor
of the weekly 'breakthrough'. On the other, the very success of
the project, and the arcane language in which much of it is
conducted, leads to a feeling of exclusion, of 'them' leading us
by the nose: we discover a character like Stanley Kubrick's Dr
Strangelove; or the fizzing laboratories that James Bond scuppers
for the good of us all.

* Edgar Allan Poe himself contributed several scientific ideas on astronomy and
biology, which were met with indifference. His prejudice against scientists may not
be entirely untinged with personal bitterness.

trilobite!

Trilobites, however, are innocent of all charges. I suspect that
the image of the palaeontologist is going to be more Professor
Calculus than Dr Strangelove. Try as I might I cannot devise a
scenario whereby trilobite science is appropriated by a totalitar-
ium regime to oppress the people. 'Aha, Mr Bond! You have
arrived just in time to witness the triumph of the trilobites, and
the end of the human race'. I would guess that 80 per cent of
scientific endeavour is as innocent of moral implications as the
trilobites. Oddly enough, it is precisely because of the harmless-
ness of such research that it is more difficult to fund; the only
science that never has to fight for funding is that with military
or medical significance.

So a plague on all the Edgar Allan Poes of our time! The truly
dull realities of which they speak are the problems of getting
financial support to do work which is not going to yield a com-
modity marketable within the twelvemonth, which is when the
accountants wheel out their electronic abacuses. To determine
what is really of value, it is necessary to take an altogether longer
view. Consider, for example, the general fascination with dino-
saurs, and recall that it was devoted, painstaking scientists who
first pieced together these fantastical animals. Sometimes this
processs took a decade: digging, preparing, piecing together dis-
parate fragments, lastly putting flesh on the bones. Imagine, if
Tyrannosaurus had remained unknown, how many children's lives
would have been impoverished. In the end, careful scientific work
was even rewarded financially, if you take into account dinosaur
films and books and a hundred less tasteful 'spin-offs'.

I speculate that my trident-bearing trilobite shown here will
one day stimulate a moment of wonder in a child, which may
convert a waverer to science, enthralled by the marvels that wait
to be found. Or even inspire a poet to take flight on some journey
of the imagination: to subvert Poe's image, vultures soar effort-
lessly, and are elegant in flight as an eagle.

Nor can you ever say: now, we know enough. We know a
dozen dinosaurs - why do we need to know thirteen? Aren't there

252

EYES TO SEE

A trident-bearing trilobite from the Devonian of Morocco, as yet unnamed.

253

trilobite!

enough trilobites in the world? To which I reply: the search is
never complete and we can never know what remains hidden
behind the next bluff, or inside the next piece of shale. My trident
bearer was a dream, a chimera that should not exist; yet it did.
The world would have been a poorer place had it remained
undiscovered. I anticipate many more such discoveries, facts, if
you will, but thrilling ones. Maybe some lucky investigator will
discover the limbs of a larval trilobite, so that we may know how
they lived as compared with the adult. Can it be that somebody
will discover the late Precambrian ancestors of the trilobites, pre-
served in a state of temporal grace? Will we be able to see the
mysteries of this time of innovation explained, as once Walcott
surveyed the mysteries of the trilobite limb? These are not Grad-
grind facts, 'dull realities': they are wings for flights of the imagin-
ation. I wish I could live long enough to know, and even if I did,
I should never cry 'enough!'.

It is more difficult to fathom future connections across the
web of knowledge, since they depend on advances in a dozen
other sciences. My conviction that connections will continue to
be made is based upon the fertility of this line of reasoning in
the past. Although, as they say of the stock market, 'past perform-
ance is no guarantee of future profitability' the fact is that these
stocks have reliably yielded a return for over a century, and the
smart money should still be on them. I can imagine that the
physicists will get to work on trilobite optics, and that we will
see more clearly how trilobites saw. Their eyes will gaze upon
vanished worlds with a pristine clarity. We will learn from mol-
ecular studies how all the living relatives of trilobites compare
one with another; we'll know what questions we should ask about
their anatomical structures. Surely, we will learn more about
how trilobites laid down their carapaces; already the electron
microscope is probing the details of the minutest crystals. Maybe
we will find that trilobite shells record tiny traces of rare elements
that act as monitors of dead seas, a mineral equivalent of the
pollutants that are picked up in tissues of living creatures, and

254

EYES TO SEE

which are measurable to parts-per-bilhon thanks to the extraordi-
nary accuracy of modern techonology. We will assuredly get to
measure geological time so finely that we can turn the tables on
history. Instead of using trilobites as chronometers we will exam-
ine their evolutionary changes against a finer-scale timepiece; thus
there will be new insights into the evolutionary mechanisms that
so intrigued the tragic Rudolf Kaufmann. Trilobites may emerge
again as the Drosophila flies of the Palaeozoic, the experimental
medium for the history of life.

These are dreams of possibilities. Yet I know that there can be
nothing better than to pursue such dreams; that the will to know
the truth is one of the better parts of human nature; and that
trilobites will reward the investigator in a currency more valuable
than dollars, and more tangible than fame.

An entire specimen of the spiny Silurian trilobite Kettneraspis from Dudley,
Worcestershire, UK. Specimen about 2cm long. (Photograph courtesy Derek
Siveter.)

255

Acknowledgements

My thanks first to Professor Harry Whittington, doyen
of trilobitologists, for admitting me into the trilobite
trade, and most recently for his generosity in supplying
me with photographs. Professors Winfried Haas, Brian
Chatterton, Euan Clarkson, Riccardo Levi-Setti, and Drs
Derek Siveter, Bob Owens, Ellis Yochelson and Adrian
Rushton, together with the Natural History Museum,
kindly supplied numerous other photographs, which have
enriched this book. Heather Godwin has been both critic
and supporter, and my debt to her is on every page. Robin
Cocks read my first draft and made several suggestions
which have improved the final work. My wife carefully
read the proofs. I thank Claire Mellish for technical sup-
port, Pam Hanus and Nicola Webb for translation from
the German. Arabella Pike and Michael Fishwick at
HarperCollins have been encouraging at all times. Arabella
in particular spotted and corrected many small errors, and
coped with the complexities of production with unfailing
good humour. My fellow commuters on the 8.02 from
Henley-on-Thames kept me cheerful on several occasions
when I might have succumbed to gloom. This book would
not have been possible without the collaboration of my
trilobite colleagues scattered all over the world, not enough
of whom are mentioned by name.

257

Suggestions for Further Reading

Kaiser, Reinhard, Konigskinder, Fischer Taschenbuch Verlag, 1998.

Kowalski, H., Der Trilobiten, Goldschneck- Verlag Korb. German
book, particularly good on Devonian species.

Levi-Setti, Riccardo, Trilobites, University of Chicago Press, 2nd
ed., 1984. A photographic atlas, beautifully illustrated with a w^ide
coverage of interesting animals.

Osborne, Roger, The Deprat Affair, Pimlico, London, 1999.

Snajdr M., Bohemian Trilobites., National Museum, Prague. Good
photographs of many of the famous trilobites of the Bohemian
region.

Whittington, H. B., Trilobites: Fossils Illustrated, vol. 2, Boydell
Press, 1992. 120 plates illustrate many fine trilobites, by the doyen
of the field.

Whittington, H. B. and others 1997. 'Treatise on Invertebrate
Paleontology', Part O Trilobita 1 (revised). University of Kansas
Press and Geological Society of America. The standard academic
work on the subject.

259

Index

Page numbers in italic refer to illustrations

Acanthopleurella 169-70

Africa 193, 232-3

agnostids 147, 175, 228-9, 205, 230,

232, 234
Agnostus 30, 70-1, 221, 228

A. pisiformis 71, 147
Alaska 193

allopatry 157, 161, 167, 174
Almond, John 61, 62, 67
Alum shale 159
amber 133, 153
Ampyx 221, 232

A. salteri Hicks 49
anaerobic environments 64-6, 159
anatomy 19, 20, 25-9, 28, 33, 60
ancestry:

arthropod 121, 128, 131-3, 247

common 81, 82, 85-6, 118-19, 127,

135
trilobite 121, 130-1, 173, 177, 179-81,

237
Andrarum 161
Antarctica 193
antennae 60, 61, 62, 67, 79, 94, 120,

225fh

Apollonov, Mikhail 78

arachnoids 122, 225

aragonite 189

Arctic 193

Argentina 112

arthropods 67, 81, 86fn, 138, 225

ancestry 121, 131-3, 247

antennae 60

Cambrian 117, 120-1, 122-3, 126-9,
230

eyes 83, 88, 90, 92, 96, 102

gills 59, 61

limbs 47, 58, 68

reproduction 211, 219-20

segments 124
asaphids 175, 232
Asaphus 71-2, 199
Australia 190, 198-9, 228, 231
Avalonia 196-8, 200
axis 28, 74, 75, 104, 105, 166

Bacon, Francis 244

bacteria 24-5, 52, 64-6, 119, 207

Baltica 194-5, 197, 200

Barrande, Joachim 50, 73, 212-17, -2^4,

216, 229, 240, 247-8, 249
Bathyurellus 191
Bathyuridae 191-3
Bathyurus 193

Beecher, Prof 60, 61, 62, 63, 66, 249
Beeny Chff 1, 11-15, 16, 76
beetles 47, 69, 142
Bergeroniellus 130
Billings, Elkanah 191
birds 142

Blake, William 249
blindness 71, 72, 110-12, 204, 205, 228,

229, 236
Bodmin 7-8, 16
Bohemia 50, 73, 107, 212, 216, 229, 241,

247
Bonne Bay 116
Bonnia 116
Borges, J. L. 210
Boscastle 1-2, 4, 5, 10, 16
brachiopods 55, 181, 206
brain 38

branchial appendages 57, 59, 61
Briggs, Derek 63, 64, 122, 124, 126, 128
Briggs-Fortey tree 126-8, 129
British Columbia 53, 117

261

INDEX

British Isles 75, 191

Brigger, W. C. 237

Brongniart, Alexandre 45, 71

brood pouch 220

Brunnich, M. T. 44

Bruton, David 40, 124, 238

Budd, Graham 131

Buihh Wells 164, 167

Bumastus 206

Bundenbach 66

Burgess Shale 53, 117, 120, 122-9, i3i>

134, 136, 230
burrowers 111, 203
Bursnall, John 32, 33

Caerfai Bay 17

calcite 25, 30, 56, 87, 100, 101, 189

crystalline 88-90, 93

high magnesian 101-2
Caledonides 201
Calymene 28, 74, 166, 221, 234

C. blinnenbachii 74

C. senaria 57
Cambrian 17, 53, 65, 69-71, 117, 152,
210

Cambrian/Ordovician boundary
238

explosion 83, 118-20, 122-5, 128,
129, 132-6

Lower (early) 83, 115-17, 121, 128-9,
131, 170, 228, 247

Middle 20, 117, 175, 215, 228-30

naming of 48-9

Upper (late) 159, 175, 224, 226, iij,
230-1
Cambridge University 38-9
camouflage 203
Canada 193
Canadaspis 124
carapace 30, 33, 47, 69, 142, 168, 212,

254
Carboniferous 5, 8, 9, 14, 76, 179, 236
Carboniferous Limestone 179
Carmarthen 107
Carolinites 105, 107, 232
caudal furca 120

cephalon 25-6, 28-9, 30, 33-4, 220
in various genera 72, j^, 108, 205
Ceraurus pleurexanthemus 55-7

chalk 87-8
Changshan 238, 239
Chatterton, Brian 212, 219
Cheirurus vjj
Chen Jun-yuan 129
Chengjiang fauna 83, 117, 129
Chiens abouient, Les (Wild) 242, 243
China 31, 83, 112, 117, 129, 130, 133, 177,

228, 230-1, 233, 238-9
chitin 50

cladistics 126-7, i3i> 22561
clams 25, 42, 65-6, 175, 206
Clarkson, Euan 93-4, 96, 100-1, 103,

104, 161
classification 126, 144, 221
Cloacaspis 65

Cnemidopyge 166, 167, 205
Cocks, Robin 197
Coleridge, Samuel Taylor 112
colour 25, 83

computer reconstruction 200
Comura 76
Conjectures and Refutations (Popper)

21
continents:

ancient 22, 185-6, 188, 232
microcontinents 196
Ordovician 191-8, 192
plate tectonics 183-6, 200-1
Conw^ay Morris, Simon 117, 122-4,

136-8
copepods 133
corals 74, 178, 179, 202
Cornwall 1-16, 55, 67, 76, 202,

208
Corynexochus 229
cranidium 33-4, 211
creationists 152, 158-9
Cretaceous 9
Cross, Frank 49-50
Cratalocephalus 76, 203
Crucible of Creation, The (Conway

Morris) 136-8
crustaceans 59, 103, 106, 111, 121, 122,

130-1, 138, 220
Cruziana 122

C. semiplicata 226, iij
Cwm Hirnant 176
Cybelurus 218

262

INDEX

Cyclopyge 72-3, 106-7, 108, 232
Czech Republic 212

Dalman, J. W. 65

Dalmanites 76, 234

Dalmanitina socialis 241

Dalziel, Pamela 13

Damesella 230

Dartmoor 7, 16

Darwin, Charles 121, 122, 125, 130,

145
Autobiography 119
Dawkins, Richard 134, 137, 13861
De Magnete (Gilbert) 187
Dean, W. T. (Bill) 140
Deanaspis goldfussi 241, 243
deception, scientific 240-4
Deprat, Jacques 240-4
Descartes, Rene 102
development time 168-9, 171-3. 221,

237
Devonian 66-7, 75, 126, 155-6, 178,

201, 210, 225, 234-6
Dewel, Ruth and Bill 246-7
Dicranurus 75
dinosaurs 5, 9, 252
Dionide formosa 241
diversity 6^-77, 205-6, 232
DNA 85, 146
doublure 30, 35, 108
dragonfly 90, 103
Drepanura 231, 233
Drosophila 81, 153
Dryden, John 63
Dudley 74, 166
Durand-Delga, M. 242
Durness 170
Dynefor, Lord 45

echinoderms 116
ecological equivalence 179—81
Edgecombe, Greg 129
Ediacara fauna 119
Edinburg Limestone 35
eggs 217, 219-20
Eldredge, Niles 155-9
Elrathia 204, 221

E. kingi 229
embryology 81, 86fh

Emergence of Animals, The

(McMenamin) 134
encrinurids 177
England 52, 179, 196
enrollment 51-2, 56, 73, 206, 221, 229
Eoredlichia 130

erosion 4, 5, 6, 8, 9, 130, 186, 191
Escher, M. C. 82
Estonia 52, 188, 194
evolution 22, 152-9, 173

background rates 174

convergent 88

divergence 81, 84-5

of eyes 80, 83

gaps in 130, 132-3

gradualistic change 167-8

and improvement 102-3, 111-12

mutation 84, 168

punctuated equilibrium 154-5,

157-9
exoskeleton 38, 177, 210-11
extinction 111, 174

mass 114, 177, 178, 181, 232-4
trilobite 77, 156, 175-6, 177, 185,

204, 236
eyes 29, 79-113. 123. 127. 254
compound 90-3, 96, 107
development of 83-4, 86, 130
field of view 93-4
hexagonal 95-7, 99, 105
large 104, 107, 108, 173
moulting 33-4, 211
parameter 107
phacopid (schizochroal) 98-103,

99, 103, 152, 155-6, 234
science of 89-90, 91, 92
small 107
soft 88

spherical aberration 101-2
stalked 71, 75, 83, 203
in various genera 69, 72-3, 76,

97-8, 228

Face of the Earth, The (Seuss) 106

Fallotaspis 83

feeding 120, 203-4

Fieldaspis 235

filter feeders 204-5

fish 67, 149, 191, 235

263

INDEX

'flatfish', Llandeilo 24, 43-4, 45^ 60,

71, 165
flatworm 82, 84
flies 69, 88, 90, 153
foraminiferans 154, 207
Forteyops 147
fossils 8-9, 14, 48-9, 115-16

earliest 17, 118-19

fragmentary 33-4, 35-6

and geographical reconstruction
188

hominid 153

Precambrian 84

small shelly fossils 117

of soft-bodied animals 117
France 75, 229

Frasnian-Famennian event 178-9, 236
free cheeks 33, 34, 73, 74. 104. 211
fruit fly 81, 153

'Funes the Memorious' (Borges) 210
Fuxhianshuia 83

genetics 80-2, 84-6, 118, 124-5, 153,

173
geographical isolation 156-7
Geological Society of London 49
geological time 9, 10, 11, 48-9.

227-37, 255
geomagnetism 187-8
Germany 66, 75, 97
Gilbert, William 187
gills 59, 61, 66, 68
glabella 28-9, 33-4, 38

in various genera 70-7, 108, 228,

229
Gondwana 188, 193-5, 197-200, 201
Gould, Stephen J. 102, 117-18, 124,

125, 129, 131, 134, 135-8, 158, 159,

i72fn
Grabau, Prof. 31
gradualism 158
Grand Canyon 53
granite 7-8, 9, 16
Great Basin 193, 231
Green, I. 56
Greenland 117, 191-3
Grifftthides 236

Gros Morne National Park 116
Grotte du Trilobite 122

growth 168, 212, 215-17, 221-3
Gunn, Thom 208

Hahn, Gerhard and Renate 236

Haldane, J. B. S. 182

Halkieria 117

Hall, James 50, 69

Hallucigenia 131

Hardwick, David 109

Hardy, Thomas 2, 11-17, 19, 29, 59,

76-7, 121, 202, 243-4
Harpes 236
Harte, Bret 137
Harvey, William 26
Haydn, Joseph 181
head, see cephalon
hedgehog 51

Henningsmoen, Prof. Gunnar 40
Henry, Jean-Louis 241
Hercynian mountains and ocean 6, 9,

15, 16, 66, 201-2
heterochrony 168, 170, 171, i72fn, 237
Hicks, Henry 49
Hinlopne Strait 42
Hirnantia fauna 176
holaspis stage 217
Holtedahl, Olaf 43. 186
Homo 153

homoeomorphy 199
homology 179

horseshoe crab 5961, 131, 173, 220, 225
Hou, Dr 129

HOX genes 80-2, 124-5, 153
Hughes, Chris 124
Hughes, Nigel 219
Hunsriick Slate 66-7
Huygens, Christian 102
hypostome 38, 204, 211, 219, 230

lapetus ocean 193, 196, 200

ice ages 176-7, 232-3

Iceland spar 88, 89

Idaho 193

Illaenus 73

Imperial College of Science and

Technology 108
Inida i32fn, 193
Indochina 240-2
insects 82, 122, 133

264

INDEX

Iowa 155

Ireland 191

iron 64, 65, 66, 67

iron pyrites 60, 63-4, 67

Island of Dr Moreau, The (Wells)

251
Isotelus 71-2, 203, 219, 234

laanusson, Valdar 163

Kaiser, Reinhard 161-2, 164
Kaufmann, Rudolf 77, 159-64, 160,

i73> 255
Kazakhstan 78
Konigskinder (Kaiser) 162

laboratory techniques 32-5, 61, 67

Lake District 150

lamella 72

Lane, Phil 33

Lantenois, Honore 240-2, 244

lapworth, Charles 170

larvae 217-19, 218, 221, 249, 254

latin 26, 143-4

Laurentia 42, 191-3, 200, 201

legs 48-78, 50, 58, 120, 122, 131

arrangement of 57-9, 60-1, 62,
68-9, 120

gills on 61

jointed 46-7, 58, 60, 61

of larvae 219
Lena River 130
Letna Formation 241
Leverhulme Trust 107
Levi-Setti, Riccardo 100-2, loj
Lewontin, R. C. 136
Lhwyd, Revd Edward 24, 43-4, 45,

60, 71, 165, 181, 248
librigena 33
Lichas 76, 234
limbs, see legs

limestones 24, 31, 35, 52, 54-5, 57, 71,
87, 107, 155, 194, 224, 227

tropical 189, 191
Limulus 5961, 131, 138, 173, 220, 225
Linnaeus, Carolus 47, 144, 249
Lister, Martin 24, 43
Llandeilo 24, 44, 45, 71, 165
Llandrindod Wells 164

lobster 46-7, 68, 90
Lu Yen-hao, Prof 239
Lyell, Charles 119

McCormick, Tim 107

McMenamin, Mark and Dianna 134

McNamara, Ken 170-1, i72fn

Magnusson, Ingeborg 161-4

Mansuy, Henri 241, 242, 243

Mappa Mundi 183-4

mating 211

Matthew, G. F. 237

Matthew, W. D. 60

Mayr, Ernst 157

Megistaspis 195

Mendel, Gregor 160

Meneviella 229

meraspides 221

Merioneth 227

Merlinia 195, 197

Miller, Jim 238

Moine Thrust 170

Mongolia 115

Monograph of the Trilobites of North

America, A (Green) 56
Morocco 75, 83, 97, 234
moulting 33-4, 38, 96, 168, 210-12,

215-16, 223
moults 37, 213
mountain formation 6-7, 184, 186
Mucronaspis 176-7, ij8, 233
mud-grubbers 76, 204, 206
muds 5, 8, 17, 64, 65, 67, 94-5, 194
mudstones 107, 165
Murchison, Sir Roderick 46, 49, 72
museums 149-51

Narodny Museum, Prague 215
natatory appendages 57-8
Natural History 137
Natural History Museum, London

139-41, 141, 144-5. 212, 239
Nature 125, 128, 167
Nature-Science (New York) 128
Nazism 162-3, 251
Nevada 191, 193, 231, 237
New Brunswick 237
New York State 50, 52, 59, 64, 69, 97,

130, 155. 191. 193

265

INDEX

Newfoundland 115-16, 131, 132, 191-3,

196, 201, 238
Nine Wells 18
nomenclature 30, 44, 46, 49, 142,

143-4, 146-8, 248
Norasaphus 199
North America 75, 155, 188, 191-3,

228, 229, 231
Norway 31, 40-2, 65, 177, 194, 201,

237. 238
Norwegian Academy of Sciences 42
Novaya Zemlya 43, 186
Novum Organum (Bacon) 244
Nui-Nga-Ma 241, 242

Oakley, Kenneth 122
octopus 88

Odontochile rugosa 214
Odontopleura 221
odontopleurids 234
Oenonella 147
Ogyginus 196, 197

Ogygiocarella 165-8, 175, 181, 199, 215,
219, 232

O. angustissima 167

O. debuchii 44, 45, 46, 71, 167
Ohio 76, 97
Oklahoma 155, 191, 193
Olenelloides 171

Olenellus 69-70, 115, 121, 130, 152,
170-2, 172, 221, 228, 237

O. armatus 171, 173

O. lapworthi 170-1, 173
Olenid Sea 159, 161
Olenidae (olenids) 65, 66, 159, 176,

231-2
Olenoides 120, 127
Olenus 65, 160-1
Oman 224-5, -226, 227
Ontario 97
ontogeny 168-9, 170, 215-17, 220-1,

222
Opik, Aklexander Armin 163, 231
Opipeuter inconnivus 42, 104-5, 107
Ordovician 65, 72, 75, 104, 111, 120,
149, 152, 175, 202, 232, 240

Cambrian/Ordovician boundary
238

end of 176-7, 232

geography 183, 186, 189, 190,
191-200, 192

limestones 31, 35, 52, 55, 227

oceans 42, 64, 108, 202-7

shales 112, 165-7
Origin of Species (Darwin) 119, 121
Oslo 65
Owens, Bob 49, 111, 179, 223, 236

paedomorphosis 17261

Pagetia 228

Pair of Blue Eyes, A (Hardy) 12-14,

22, 243
palaeomagnetism i88, 189, 197
Palaeozoic 21, 74
Palmer, Alison R. 231
Pangaea 184-6, 188, 193, 201
Parabarrandia 108-9, no
Paradoxides 19, 20, 30, 70, 71, 213, 229,
237

P. davidis 215

P. hicksi Salter 49

P. oelandicus 147

P. paradoxissimus 30
Parapilekia jacquelinae Fortey 148
Pattern of Evolution, The (Eldredge)

155
Peel, lohn 117
Pembrokeshire 49
Pentargon Bay 3-6, 9, 10, 14, 67
Permian 77, 181, 184, 193, 236
Petigurus 191
phacopids 178, 236
Phacops 67, 68, 75-6, 157-9, 199. 203,

211-12, 221, 234
P. rana 76, 156
schizochroal eyes 97-103, 99, 103,

155-6
Phillips, John 76, 77
Phillipsia 76-7
phyla, Cambrian 134-5
plankton 133, 154, 168, 177, 217, 219,

229
plate tectonics 9, 184-7, 190, 198, 206
pleurae 28, 73, 104, 166
Poe, Edgar Allan 249, 251
Poland 177
polyphyly 123
Popper, Karl 21

266

INDEX

Porth-y-rhaw 18

Possible Worlds (Haldane) 182

Postlethwaite, J. 150

Prague 214-15, 240

Precambrian 80, 84, 85, 119, 123, 129,
132-3, 185, 194, 254

predators 120, 203, 204-5

Pricyclopyge 99, 107

proetoids 236

Proetus 178-9, 234, 236

Profallotaspis 115

protaspides 168, 217-21, 218, 223

Protocystites walcotti 116

Proust, Marcel 247

Ptychoparia striata 229

Pulvis et umbra (Stevenson) 21

punctuated equilibrium 154-5, 157-9

pygidium 26, 27-8, 30, 33, 61, 161, 221
evolutionary change in 167-8
in various genera 70, 71, 73, 76,
108, 166, 228, 229

quartz 3, 4-5, 7

Radiaspis 75

radioactive isotopes 8

Ray, John 144

Raymond, Percy E. 12361

recapitulation 173

Redlichia 228

Remopleurides 219

reproduction 219-20

ribosomes 84-5

RNA (ribonucleic acid) 85

rock successions 153-4, 159> 165, 166

Rome, New York 59, 67

Rothschild, Lord 150

Royal Society 249

Philosophical Transactions 43-4, 45
Rules of Zoological Nomenclature

146-7
Rushton, Adrian 150, 169
Rusophycus 122
Russia 194
Rutherford, Ernest 148

St David's 17, 32, 49, 215

St Juliot's Church 7, 13, 15-16

Salter, John 49, 77, 167, 227

Salter's Ampyx 49

Sanctacaris 124

sandstones 17, 187, 224

Sao hirsuta 215, 216

Scandinavia 159, 161, 231, 234

Schroeter, J. S. 50

science 15, 21-3, 43, 63, 112-13, i34'

149, 207, 244-5, 246-54
scorpions 131, 225-6
Scotland 69, 170, 191-3, 201
Scutellum 76
sea mats 55, 203, 206
Sedgwick, Revd Adam 39, 48
Sedgwick Museum, Cambridge 32,

124
segmentation 124-5

see also thoracic segments
Seilacher, Dolf 225, 227
Selwood, E. B. 6
senses 60, 79-80
sensory hairs 36
Serolis 145
Service Geologique de I'lndochine

240-1
shales 5, 8, 17, 59, 64, 76, 112, 116, 165,

167, 170, 189
Sheinton Brook 112
Sheldon, Peter 165-8, 176
shells 24-5, 50, 116-17, ii9> 133. 136,

154, 206
see also carapace
Shergold, John 198, 200
Shropshire 74, 112, 196, 197, 223
Shumardia 76, 112, 169-70, 221-3, 222

S. crossi Fortey & Owens 50
Siberia 115, 130, 132, 194
Sicily 236
silica 35-6, 87
Silica Shale 76
Silurian 49, 52, 74, 149, 177-8, 200,

2i2fn, 232, 234
Silurian System, The (Murchison) 46
Sirius Passet 117
Skryje 215
Skye 191

slate 3, 5, 6, 8, 12, 49, 66
small shelly fossils 117
Smithsonian Institution 100, 134
snails 42, 55, 206

267

INDEX

Snow, C. P. 249

Societe Geologique de France 241-2

soft-bodied animals 83, 117, 119,

122-3, 131
soft-shelled trilobites 211-12
South Aft-ica 177
South America 193
Spain 229
'Spandrels of San Marco' (Gould &

Lewontin) 137
species:

endemic 190

endurance of 157

generation of 22, 152-3, 154, 156-8,
170-3, 236

naming of 141-9

type specimens 144-6, 150
spiders 88, 103
spines 36, 203, 229-30, 234-5

genal 33, 71, 72, 75, 211, 226

larval 221

leg 61-3, 120

pleural 70

in various genera 69-70, 75, 76,
166, 171
Spitsbergen 31, 40-2, 47, 65, 104, 105,

148, 176, 193, 218, 218
Stevenson, Robert Louis 21, 149
stinkstones 159
stomach 38
Stormer, Lief 12361
streamlining 108-10
Stubblefield, Sir James 169, 221-3,

222, 224, 249
Stiirmer, Prof Wilhelm 67
subduction 186, 200
Suess, Eduard 106, 193
sulphur 64, 65-6, 159
sulphur bacteria 64-6, 159
surface features 36, 142
suture lines 33-4, 70, 211, 228
Sweden 52, 70, 71, 73, 161, 165, 188,

194-5
swimmers 105-6, 107-11
Swofford, David 127
symbiosis 66, 159
Symphysurus 51
Sy Sterne Silurien de la Boheme
(Barrande) 212

tail, see pygidium
tardigrades 246
taxonomy, see nomenclature
tectonism 4, 5, 6-7, 18

see also plate tectonics
Tempest, The (Shakespeare) 90-1
Termier, Prof 242
tetrapods 126
Texas 193

Thailand 176, 227-8, 233
thoracic segments 26-8, 33, 46

in enrollment 51

release of 168-70, 215-17, 221-3, 222

in various genera 70-4, 76, 166, 228
tillites 176

Time Frames (Eldredge) 158
Timor 236

Tjernvik, Torsten 194-5
Tornquist's Sea 197, 198
tortoise 27, 30
Towe, Kenneth M. 100
tracks 122, 131, i32fn, 204, 223-7, 226
Trenton Falls, New York 52, 54
Triarthrus 59, 60-5, 62, 67, 106, 120,

159, 205, 221
Trilobites, Les (Brongniart) 45
trinucleids 175, 232
Trinudeus 72, 73, 111, 205, 219, 221,

234
T. fimbriatus 49
tubercles 36, 72, 75, 76
type specimens 144-6, 150

underside 30, 38
Urals 186, 194, 202
Utah 193, 231, 238
Utica Shale 59, 61, 66, 67

velvet worms 131

Vendian strata 119

vertebrates 81, 82, 86fn

Vietnam 240-2

Vinice Formation 241

Virginia 35

volcanoes 52, 182-3, 186, 206

Walch, Herr 44

Walcott, Charles Doolittle 52-9, 54,
58, 61, 77, 120, 122, 193, 237

268

INDEX

Walconaspis 147 Whittingtonia 147

Wales 48-9, 55, 107, 164, 194, 229, 231 Wild, Herbert 243-4

ancient 196-7 Wills, Matthew 128

north 48, 176, 227 Wilson, E. O. 207

south 24, 45, 49, 111 Withers, T. H. 140

western 17-18, 20, 25 Wonderful Life (Gould) 117, 124, 125,

water fleas 219 138

Wells, H. G. 251 woodlice 51

Wenlock Limestone 74 worms 42, 67, 86fh, 95, 207

Whittington, Dorothy 39 Wrekin, The 112

Whittington, Harry B. 31, 35-9, 61,

62, 120, 122-4, 219, 221, 249 x-ray photography 67

269

'Give Richard Fortey a trilobite and a place to stand and he will move the
world... Lively, personable, yet vast in its implications, Trilobite! is just
what good science writing should be and so seldom is.'

'Fortey, the Natural History Museum expert who wrote the knockout
Life: An Unauthorised Biography has followed it up with something more

intense, more personal and, in the long run, more enlightening. Trilobites
are Fortey 's obsession. He has used their story to tell a number of other

stories: of the revelations of evolution, of how science is done, and of the
strange people who do it. If there is any justice Trilobite! will do for

palaeontology what Longitude did for navigation.'

'This sparkling book reminds us all what science is really about...
Trilobites persisted for 300 million years (man has so far survived half a
per cent as long) . Through their unique multifaceted eyes, evolution and

extinction are placed in perspective. Fortey explodes the cliche of the
scientist as a white coat that won't emote. What better way to remind us
that, despite being foimded on theory and objective observation, science is
very much the work of flesh and blood.*

'In Richard Fortey 's capable hands the humble grey trilobite has been
transformed into the E.T of the Lower Palaeozoic — a remarkable and
fascinating book.'

'Fortey 's books are always a treat. It's not just that they are beautifully
written in mellifluous prose but that his vision is wonderfully humane.'