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Collection de
microfiches.
Canadii Institut* for Historical IMicroreproductions Institut Canadian da microraproductions historiquaa
1980
m
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D
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possible considering tlie condition end iegibility
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Is symbols — ► signifis "A SUIVRE", le symbols
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Nstionsi Librsry off Csnsds
L'sxemplsire ffilmA fut reproduit grflce A Is
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Msps or pistes too Isrge to be entirely included
in one exposure sre ffilmed beginning in the
upper left hsnd corner, lefft to right end top to
bottom, 88 msny ffrsmes ss rsquired. The
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Les csrtes ou los pisnches trop grsndes pour Atre
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1 2 3
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1
THE CHAIN OF LIFE
IN
GEOLOGICAL TiME.
td
u
h
lb
^ SKETCH OF THE ORIGIN AND SUCCESSION OF
ANIMALS AND PLANTS.
BY
J. W. DAWSON, LL.D., F.R.S., F.S.S., ETC.
AUTHOR OF
"ACADIAN GEOLOGY," "THE STORY OF THE EARTH," " LIFe's DAWN ON EARTH.'
"THE ORIGIN OF TH"t WORLD," ETC.
WITH NUMEROUS ILLUSTRATIONSc
THE RELIGIOUS TRACT SOCIETY,
56, Paternoster Row; 65. St. Paul's Churchyard;
AND 164, Piccadilly.
bCC, (II
.t>3
13230
~0/9^<i
v/ 1' i
7iyO
2^c)
LONDON :
R. Clay, Sons, and Taylor,
lihEAI) STREET HILL.
K^
PREFACE.
Questions as to the origin and history of life are not at the
present time limited to mere philosophical speculation and
poetical imagining. The solutions of these questions are
now supposed to be based on the facts of Biology and
Palaeontology; and, establishing themselves on these facts,
the bolder speculators suppose that they can scale heaven,
dethrone God, ar ^ sweep away all belief in the spiritual
nature and higher destinies of man.
No portion of our modern acquisitions in science is more
closely connected with these daring speculations than that
which relates to the succession of forms of life in geological
time ; and none is more unfairly dealt with by the more
extreme theorists. On the one hand, they parade carefully
selected series of fossil species as demonstrating the reality
of continuous derivation. On the other hand, when this
process fails to meet the requirements of the facts, they
affirm that the imperfection of the record, or of our know-
ledge of it, invalidates any testimony of Palaeontology on.
the subject.
vi PREFACE.
It is in these circumstances most desirable that tliose who
are not specialists in such matters should be in a position
to judge for themselves ; and it does not appear impossible,
in the actual state of knowledge, to present, in terms intel-
ligible to the general reader, such a view of the ascertained
sequence of the forms of life as may serve at once to give
exalted and elevating views of the great plan of creation,
and to prevent the deceptions of pseudo-scientists from doing
their evil work. Difficulties, no doubt, attend the attempt.
They arise from the enormous accumulation of facts, from the
uncertainties attending many important points, from the new
views constantly opening up in the progress of discovery, and
from the difficulty of presenting in an intelligible form the
preliminary data in biology and geology necessary for the
understanding of the questions in hand. In order, as far as
possible, to obviate these difficulties, the plan adopted has
been to note the first known appearance of each leading type
of life, and to follow its progress down to the present time or
until it became extinct. This method is at least natural and
historical, and has commended itself to the writer as giving
a very clear comprehension of the actual state of our know-
ledge, and as presenting some aspects of the subject which
may be novel and suggestive even to those who have studied
it most deeply.
In selecting examples and illustrations, the writer has en-
deavoured to avoid, as far as possible, those already familiar
to the general reader. He has carefully sought for the latest
facts, while rejecting as unproved many things that are con-
fidently asserted, and has endeavoured to avoid all riiat is
PREFACE. vii
irrelevant to the subject in hand, and to abstain from all
technical terms not absolutely essential. In a work at once
so wide in its scope, so popular in its character, and so limited
in its dimensions, a certain amount of hostile criticism on the
part of specialists is to be expected, some portion of it per-
haps just, other portions arising from narrow prejudices due
to limited lines of study. The writer is willing to receive
such comments with attention and gratitude, but he would
deprecate the misuse of them in the interest of those coteries
which are at present engaged in the effort to torture nature
into a confession of belief in the doctrines of a materialistic
or agnostic philosophy.
The title of the work was suggested by that of Gaudry's
recent attractive book, Les Enchaineme?its du Monde animal.
It seemed well fitted to express the connection and succession
of forms of life, without implying their derivations from one
another, while it reminds us that nature is not a fortuitously
tangled skein, and that the links which connect man himself
with the lowest and oldest creatures bind him also to the
Throne of the Eternal.
J„ VV. DAWSON.
McCiILL COLLEGF, MONTREAL
CONTENTS.
43
(HAT.
I'ACE
I. Preliminary Considerations as to the Extent and
Sources of our Knowledge i
II. The Beginning of Life on the Earth 21
III. The Age of Invertebrates of the Sea
IV. The Origin of Plant Life on the Land. .... 89
V. The Appearance OF Vertebrate Animals n;
VI. The First Air-breathers. . . t^7
*j7
VII. The Empire of the Great Reptiles .165
V^in. The First Forests of Mcdern Type 185
IX. The Reign of Mammals 207
X. The ADvtNT of Man 2^1
XL Revilw of the History of Life • • • 253
LIST OF ILLUSTRATIONS.
Frontispiece. — Life in the Silurian Age
To face Title.
FIO.
I.
2.
3-
4-
5.
6.
7.
8.
9.
lO.
II.
12.
\2a.
13.
14.
15.
16.
17.
18.
19.
20.
21.
Bank of stream or coast, showing stratification
Section at Niagara Falls .
Section obtained by boring, near Goderich, Ontario .
Inclined beds, holding fossil plants ....
Ideal section of the Apalachian Mountains .
Generali^ed section across England from Menai Straits
the Valley of the Thames .....
Generalised section from the Laurentian of Canada to the
coal-field of Michigan ......
Unconformable superposition of Devonian Conglomerate on
Silurian slates, at St. Abb j Head, Berwickshire
Section of Trenton Limestone, Montreal
Dia'^ram showing different state of fossilisation of a cell of a
Tabulate Coral .......
Cast of erect tree {Si^llaria) in Sandstone .
Protichnites septem-notatus ......
Footprints of modern Limulus, or king-crab
Current markings on shale, resembling a fossil-plant .
Frontispiece. Alagnified and restored section of a portion of
Eozoon canadense .......
Ideal section, showing the relations of the Laurentian and
Huronian ........
Small weathered specimen of Eozoon ....
Nature-printed specimen of Eozoon slightly etched with acid
Magnified group of canals in supplemental skeleton of Eo-
zoon ..........
Portion of Eozoon magnified 1<X) diameters
Magnified portion of shell of Calcarina . . . .
Amaba, a fresh- water naked Rhizopod ; and Actinophrys,
a fresh-water Protozoon .......
Nonionina^ a modem marine Foraminifcr . . . .
I'A(i
4
4
5
6
7
10
13
IS
16
17
iS
18
20
24
28
29
31
3f
32
34
34
LIST OF ILLUSTRATIONS.
FIG.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33-
34-
35.
36.
37-
38.
39.
39«.
40.
41.
42.
43.
44.
44a.
45.
46.
47.
48.
49.
50.
SI.
52.
53.
54.
55.
55«-
56.
57.
58.
59.
59<?.
60.
61.
62.
Billings)
ites
le or rioat
(/5/
yozoan
eroscopic
'iiWus (Ed
cells
ward
Stromatopora concentrica
Cannopora planulata ......
Archaocyathus miuganeiisis. A Primordial rrotuzoon
Receptaculites. Restored
Section of Loftiisia Persica. An Eocene Foraminifer
Foraminiferal Rock Builders, in the Cretaceous and Eocene
Frontispiece. A Cambrian Trilobite (ParadoxiJes micmac)
Group of Cambrian Animals .....
Portion of skeleton of Hexactinellid Sponge (Caiop/yc/iimii)
Protospongia fcnestrata (Salter)
Astylospongia pncmorsa (Roemer)
Spicules of Lithistid Sponge {Trichospongia
Oldhatnia antiqua (Forbes)
Didyomma sociale. Enlarged
Didyonema Webster i (Dn.) .
Group of modern Hydroids allied to Graptol
Silurian Graptolitida; ....
Central portion of Graptolite, with membra
chogiapstis odobrachiatus. Hall)
Ptilodictya acuta (Hall). Bryozoan
Fenestella Lyelli (Dn.). A Carboniferous B
Chaetetes fibrosa. A Tabulate Coral with m
rt, Stenopora exilis (Dn.). b, Chaetetes tur
and Haine) .....
Living Anthozoan Coral {Astttra)
Tabulate Corals (Halisites and Favositfs)
Rugose Coral (Heliophyllum Halli)
Zaphrentis prolifica (Billings)
Rugose Corals {Zaphrentis Minas, Dn., and
Jiillingsi, Dn.) ....
Modern Crinoid {Rhizocrinus Lofotensis)
Palccaster Niagarensis (Hall)
Palcechinus ellipticus (McCoy)
Pletirocystites sqtiamosus
Heterocrimis simplex (Meek)
Body of Glyptocrinus ....
Fxtracrimis Briareus ....
Pentacrinus caput-medusce
Lingtda anatina ....
Cambrian and Silurian Linguloe .
Terebratula sacculus (Martin)
Discina Acadica (Hartt)
Brachiopods; genus Of this . . .
Rhynchonella increbrescins (Hall)
Spirifer mucronatus (Conrad)
Athyris subtilita (Hall)
Productus cora (D'Orbigny) .
Group of Older Palaeozoic Lamellibranchs
Conularia planicostata (Dn.). A Carboniferous Pteropod
Cyath iphylluin
PAt;K
35
37
38
39
41
44
46
49
50
5'
5'
52
^2
53
54
55
55
55
56
56
57
58
59
59
60
60
61
62
62
63
63
03
64
64
<>5
65
66
66
66
66
67
67
68
69
70
LIST OF ILLUSTRATIONS.
XI
KIG.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
74«.
75.
76.
76a.
77.
78.
79.
80.
81.
82.
83.
84.
86.
87.
88.
89.
90.
91.
92.
93.
94.
'95.
96.
97-
98.
99.
100.
lOI.
102.
103.
Silurian Sea-snails
Squid {Loligo) ....
Pearly Nautilus {/Vouri/m pcmpilius)
Orthoceras .....
GotHphoceras ....
Liiuitcs
Nautilus Avonensis (Dn.) .
Goniatites crenistria (Philips)
Ceratites noJosus (Schloth) .
Ammonites Jason (Reinecke)
Suture of Ammonites componens (Meek)
Cretaceous Ammonitidri'
Belemnite .......
Bclemnoteuthis anttquiis
Cambrian Trilobites ....
Transverse section of Calymene. A Silurian Trilobite .
Burrows of Trilobite and of modern King-crab
Silurian Trilobites .....
Devonian and Carboniferous Trilobites
Palaeozoic Ostracod Crustacecns . . . . .
Pterygoms anglicus .......
Amphipeltis paradoxus (SrJter)
Anthropahimon Hit liana (Du.) .
Frontispiece^ Cordaites, of the group of Dory-Cordaites
Protannularia Harknessii (Nicholson) ....
American Lower Silurian Plants .....
Eopteris Alorieni (Saporta)
Fragment of outer surface of Glyptcdendron of Claypole
Psilophyton princeps (Dn.) . . . . . ' .
Trunk of a Devonian Tree-fern (Caulopteris Lockivoodi, Dn.
Frond of Archa:opteris Jacksoni (Dn.)
Portion of a branch of Leptcphleum rhombicum (Dn.).
Calamites radiattis (Brongniart)
A Devonian Taxine Conifer {Dadoxylon ouangondianum, Dn.
Group of Devonian Fruits, etc
Structures of the o'dest-known Argiospermous Exogen {Sy
ringoxylon mirabile, Dn.) . . . , .
Asterophyllites parvula 'Dn.) and Sphenophyllum antiquum
(Dn.)
Calamites .....
Carboniferous Ferns
Carboniferous Tree-ferns
Lepidodend; i corrvgatum (Dn.) .
Sigillarice of the Carboniferous .
Trigonocarpuii Hookeri (Dn.)
Frontispiece. Pteraspis. Restored
Lower Silurian Conodonts .
Lower Carboniferous Conodont .
i'A(;k
70
7«
72
73
73
73
74
74
76
76
77
78
78
79
80
81
82
83
f3
84
85
85
88
9'
92
93
94
95
97
98
98
99
100
lOI
102
103
104
105
107
108
109
III
116
118
119
xn
LIST OF ILLUSTRATIONS.
FIG.
104.
105.
io6.
107.
108.
109.
no.
in.
112.
"3.
114.
116.
117.
118.
119.
1 20.
121.
122.
123.
124.
125.
126.
127.
128.
129.
130.
131-
132.
^33-
134-
135.
136.
137.
138.
139.
a, lltcd sliield of an Upper Silurian Fish {Cyathaspis) ; b, Spine
of a Silurian Shark {Onchus tenui-striafus, Agasp.) ; r.
Scales of Thelodus ' [
Cephala^pis Dawsoni (Lankester) • . . . .
Devonian Placoganoid Fishes {Pierichihys fornnfus, Cephal-
aspis LyelH)
Devonian Lepidoganoid Fi-hes {Difacanthus and Osleolepis)
Modern Dipnoi {Cera,odus Fvst,ri anJ Lepidodren annectus)
Anterior part of the palate of Dipterus
Dental plate of C<7«r/5<7tf'«j//jVa/«j (Dn.) . . *
Dental plate cf Ceratodtis Barrandii . ...
Dental plate of Ceratodtis sirratus
Jaws of Dinichthys Hertzeri (Newberry)
Low&c ]a.\y oi Dinichthys Hcrt!:en
Jaws of Lepidosiren .......
A sn«all Carboniferous Ganoid {Palaoniscns {Rhadinichthys
Modttius, Dn.)
Teeth and Spines of Carboniferous Sharks . . '.
Teeth of Cretaceous Sharks {Otodus anA PtycJiodus)
Tooth of a Tertiary Shark {Carcharodon) .
A Liassic Ganoid (Dapedius)
Cretaceous Fishes of the modern or Telecstian type {Bery'x
Le7vesiensis and Portheus molossus. Cope)
Modern Ganoids {Polypterus and Lepidostens)
Frontispiicc. A Micrcsaurian of the Carboniferous Period
{Hylonomus LyelH)
Wings of Devonian Insects ....,!
Land-snail [Pupa vettista, Dn.) .....
I-and-snail {Zonitts {Comihis) prisms^ Carpenter)
Millepedes (Xyhbius sigillarue, Dn. ; Archiultis xylobioides
Scudder; X. farcius, Scudder)
Wings of Cockroaches
Wing of May-fly {Haplophlebium Barnesii, Scudder) .
Abdominal part of the larva of a Carboniferous Dragon-fly
{Libellula carbonaria, Scudder) ....
A Jurasi-ic Sphinx-moth (Sphinx Snellen', Weyenburgli)
An Eocene Butterfly {Prodryas persephone, Scudder) .
Carboniferous Scorpion (Eoscorpius carbonarius. Meek and
Worthen)
Footprints of one of the oldest known Batrachians, probably
a species of Dendrerpeton
Archtgosaurtis Decheni
Ftyonius * ]
A large Carboniferous Labyrinthodont (Bapheles plankep.
Owen)
Baphetes plankeps (Owen)
A lizard-like Amphibian {Hylononms aciedentatus)
Stelliosaurtis longkostattts (Fritsch) ....
PAGE
121
122
123
124
124
125
126
126
127
127
128
128
129
130
131
132
132
133
134
136
140
143
143
145
146
147
148
149
ISO
152
154
154
155
156
»57
158
idMiaMiaaH
LIST OF ILLUSTRATIONS.
Xtll
FIG.
140.
140a.
141.
142.
142a.
\42b.
143-
144
145.
146.
147.
148.
149.
150.
151.
152.
153.
154.
155.
156.
157-
158.
159
160.
161,
162.
163.
164.
165.
166.
167.
168.
169.
170.
171.
172.
173-
174.
175.
176.
177.
178.
Section showing the position of an erect SigUlaria, contain
ing remains of land animals ......
Section of base of erect .Sjoil/aria, containing remains of
land animals
Frontispiece. Inhabitants of the English Seas in the Age <
Keptiles '
Arm of Proterosaurus Speneri
Skeleton of Ichthyosaurus ......
Head of Pliosaurus ••.....
Paddle of Plesiosaurus Oxouiensis ....
Skeleton of Clidastes
An Anomodont Reptile of the Trias (oicynoJon ' lacerticeps
Owen)
A Theriodont Reptile of the Trias {Lycosaurm) '. ]
Skeleton of Pterodochylus crasiirostris . . , \
Restoration of Phamphorhyncus Pucklandi .
A Jurassic bird {ArchcBOpettyx niacroura) . .
Jaw of a Cretaceous Toothed Bird {Ichthyornis disfiar)
Jaw of Bathygnaihus borealis (Leidy) ....
Hadrosaurus Foulkii (Cope)
Ja'vs of Megalosaurus ......
Tooth of Megalosaurus ......
Compsognathus ... ....
Frontispiece. Lower Cretaceous Leaves
Sassafras cretaceum (Newberry) . , . .
Liriodendron primarum (Newberry)
Onoclea sensibilis ......
Davallia tenuifoha
Eocene Leaves ....,.*
An Ancient Clover {Trifoliuni palaogceum, Saporta) '.
An Eocene Maple (Acer sextianus, Saporta)
A European Magnolia of the Eocene {M. diance, Saporta)
Flower and Leaf of Bombax sepultiflorum .
Branch and Fruit of Sequoia Couttsice (Heer) . \
Cinnamomum Scheuchzeii (Heer) ....
Frontispiece. Sivatherium giganteum . . ' .
Jaw of Dromatherium sylvestre (Emmons) .
Myrmecobius fasciatus
Jaw and Molar of Phascolotheriuin Bucklandi
Jaw a !d Pre-molar of Ptagiaulax Becklesii . [
Restoration of PaUcotherium magnum ....
Skull of Lower Eocene Perissodactyl (Coryphodov Ham it u
Fore-foot of Coryphodon
Skull of Upper Eocene Perissodactyl {Dinoceras mirabilis)
Fore-foot of Dinoceras
Skull of Miocene Perissodactyl {Brontotherium incens. Marsh)
Series of Equine Feet
Skull of generalised Miocene \<\xm\na.ni (Oreodon major)
Lower Jaw of Megatherium ....
PAGE
l6o
i6i
166
167
168
168
170
170
170
170
171
172
173
»74
175
176
177
179
184
190
191
191
192
194
195
195
195
196
197
198
206
209
209
210
210
211
2r4
215
216
217
217
218
221
222
XIV
LIST OF ILLUSTRATIONS.
FIG.
PAGE
ns)
1 79. Ungual Phalanx and Claw-core of Megatherium .
180. 'J 00th of Eocene Whale (Zeuglodon cetioides)
181. Mastodon ohioticus ......
182. Head of Dinotherium giganteum ....
183. '^'wi^ oi Y.QC&xvz )&z.\. {Vesper tilio aquensii) .
184. Skull of a Cymetar-toothed Tiger \Muhairodus cultridi
185. Lower Jaw of Dryopitfucus Fontani .
Frontispiece. Contemporaries of Post-Glacial Man
186. Elephas primigenius ......
187. Tooih. oi Elasmotherium
188. Engis Skull
189. Outlines of Three Prehistoric European Skulls compared with
an American Skull
190. Flint Implements found in Kent's Cavern, Torquay
191. Bone Harpoon (Palseocosmic) ....
192. Sketch of a Mammoth carved on a portion of a Tusk of the
same Animal 249
222
223
225
226
226
228
229
232
241
242
243
244
245
246
Tabular View of Geological Periods and of Life-Epochs.
Geological Periods.
( Post-Tertiary L^^^^^
o"" |Po3t-Glacial.
Cainozoic
or
Neozoic.
Quaternary.
Tertiary
/Pleistocene or
Glacial.
' Pliocene.
I Miocene.
\Eocene.
Cretaceous
,, / Jurassic
Mesozoic. n -^
Triassic
I Upper,
•1 Lower, or
(Neocomian.
(Oolite.
\ Lias.
I Upper,
Middle, or
Muschelkalk.
Lower.
Age of Man
and modern
Mammals.
Age of Extinct
Mammals.
(Earliest
Placental
Mamm-ils )
PALiEOZOIC
Permian
! Upper,
Middle, or
Magnesian Limestone.
Lower.
/Upper Coal-Formation.
^ , .y I Coal- Forma' ion.
Ca rlontferous Carboniferous Limestone.
V Lower Coal-Formation.
Devonuift
Silurian
Cambrian .
{Upper.
Middle
Lower.
^ Upper.
X Lower, or
(Silico-Cambrlan.
{Upper.
Middle.
Lower.
Hurcnian . ^^ll%\
I /Upper or
Eozoic. < ^ iNorian.
Laurentian . » Middle,
A^e of Reptiles
and Birds.
(Earliest
Murbupial
Mammals. )
(Earliest
true Reptiles.)
Age of
A mphibians
and Fishes,
Age of
Mollusks,
Corals, and
Cmstaccans.
I Lower, or
\Boii
tBojian.
Age of
Protozoa.
(First animal
remains.)
Age of
A ngiosperms
and Palms.
(Earliest
Modern Trees.)
Age of
Cycads and
Pines.
Age of
Acrogens and
Gyninosperms.
(Earliest
Land Plants.)
Age of Algee.
Indications of
Plants
not determinable.
THE CHAIN OF LIFE.
CHAPTER I.
PRELIMINARY CONSIDERATIONS AS TO THE EXTENT AND
SOURCES OF OUR KNOWLEDGE.
IT is of the nature of true science to take nothing on trust or
on authority. Every fact must be established by accurate
observation, experiment, or calculation. Every law and prin-
ciple must rest on inductive argument. The apostolic motto,
" Prove all things, hold fast that which is good," is thoroughly
scientific. It is true that the mere reader of popular science
must often be content to take that on testimony which he
cannot personally verify ; but it is desirable that even the most
cursory reader should fully comprehend the modes in which
facts are ascertained and the reasons on which conclusions are
based. Failing this, he loses all the benefit of his reading in
so far as training is concerned, and cannot have full assurance
of that which he believes. When, therefore, we speak of life-
epochs, or of links in a chain of living beings, the question is
at once raised — What evidence have we of the succession of
such epochs? This question, with some accessory points,
must engage our attention in the present chapter.
B
2 THE CHAIN OF LIFE.
Geology as a practical science consists of three leading parts.
The first and most elementary of these is the study of the dif-
ferent kinds of rocks which enter into the composition of those
parts of the earth which are accessible to us, and which we are
in the habit of calling the crust of the earth. This is the sub-
ject of Lithoiogy, which is based on the knowledge of minerals,
and has recently become a much more precise department of
science than heretofore, owing to the successful employment of
the microscope in the investigation of the minute structure and
composition of rocks. The second is the study of the arrange-
ment of the materials of the earth on the large scale, as beds,
veins, and irregular masses ; and inasmuch as the greater part
of the rocks known to us in the earth's crust are arranged in
beds or strata, this department may be named Stratigraphy.
A more general name sometimes employed is that of Petro-
graphy. The third division of geology relates to the remains
of animals and plants buried in the rocks of the earth, and
which have lived at the time when those rocks were in
process of formation. These fossil remains introduce us
to the history of life on the earth, and constitute the subject
of Palceontoiogy.
It is plain that in considering what may be learned as to
epochs in the history of life we are chiefly concerned with the
last of these divisions. The second may also be important as
a means of determining the relative ages of the fossils. With
the first we have comparatively little to do.
Previous to observation and inquiry, we might suppose that
the kinds of animals and plants which now inhabit the earth
are those which have always peopled it ; but a very little study
of fossils suffices to convince us that vast numbers of creatures
once inhabitants of this world have become extinct, and can
be known to us only by their remains buried in the earth.
When we place this in connection with stratigraphical facts,
we further find that these extinct species have succeeded each
other at different times, so as to constitute successive dynasties
PRELIMINARY CONSIDERATIONS. 3
of life. On the one hand, when we know the successive ages
of fossil forms, these become to us, like medals or coins to the
historian, evidences of periods in the earth's history. On the
other hand, we are obliged in the first instance to ascertain the
ages of the medals themselves by their position in the succes-
sive strata which have been accumulated on the surface. The
series of layers which explorers like Schliemann find on the
site of an ancient city, and which hold the works of successive
peoples who have inhabited the place, thus present on a small
scale a faithful picture of the succession of beds and of forms
of life on the great earth itself.
Our leading criterion for estimating the relative ages of rocks
is the superposition of their beds on each other. The beds of
sandstone, shale, limestone, and other rocks which constitute
the earth's crust have nearly all been deposited thereon by water,
and originally in attitudes approaching to horizontality. Hence
the bed that is the lower is the older of any two beds. Hence
also, when any cutting or section reveals to us the succession
of several beds, we know that fossil remains contained in the
lower beds must be of older date.
We can scarcely walk by the side of a stream which has
been cutting into its banks, or at the foot of a sea-cliff, or
through a road-cutting, without observing illustrations of this.
For instance, in the section represented in Fig. i, we see at
the surface the vegetable soil, below 'this layers of gravel and
sand, below this a bed of clay, and below this hard limestone.
Of these beds a is the newest, d the oldest ; and if, for
example, we should find some marine shells in d, some fresh-
water shells in c, bones of land animals and flint arrow-
heads in d, and fragments of modern pottery in a, we should
be able at once to assign their relative ages to these fossils,
and to form some idea of the succession of conditions and of
life which had occurred in the locality.
On a somewhat larger scale, we have in Fig. 2 a section of
the beds cut through by the great Fall of Niagara. All of
n 2
ill
iil
1
4 THE CHAIN OF LIFE.
these except that marked a are very ancient marine rocks,
holding fossil shells and corals, but now forming part of the
interior of a continent, and cut through by a fresh-water
river.
, , . -^ • .
I' .— ^■'v^r-^-v- i^'-i:3\r'-
Fir.. 1. — Bank of stream or coast, showing stratification,
a. Vegetable soil, b, Gravel and sand, c. Clays, d. Limestone rock, slightly
inclined.
In deep mines and borings still more profound sections
may be laid open, as in Fig. 3, which represents the sequence
of beds ascertained by boring with the diamond drill in search
c
d
e
Fic;. 2, — Section at Niagara Falls, showing the strata cut through by the action of the
Fall. Thickness of beds about 250 feet.
n, Boulder clay and gravel — Post-pliocene.
^c SialarashTir'""' 1 ^Pper Silurian, with
d, SfniTlit^Itone "'- - ^^^^"^ -^
e. Medina sandstone ) morals.
of rock fait near Goderich in Canada. Here we have a suc-
cession of 1,500 feet of beds, some of which must have been
formed under very peculiar and exceptional conditions. The
beds of rock salt and gypsum must have been formed by the
drying up of sea-water in limited basins. Those of Dolomite
PRELIMINAKV^ CONSIDERATIONS.
impiy precipitation of carbonate of lime and magnesia in the
sea-bottom. The marls must have been formed largely by the
driftage of sand and clay, while some of the limestone was
12
'4
'5
i6
17
■: ,"j¥£^V-^'-^--- v-^
: — ' — __-. ..
___.,. __.__,..
._---_- _ — -. _ . ^-. _ - -. - - .
till
\ \ : 1
J ^
1 1 1
_i ^ 1 i
1 1 1 1
' i '
1 ■' ' 1 (
' ' 1
-■-—'. — - — ——.-:. ,J.Z- -.'
—
-
:-^^:;--;-:.-r
- - ■ -----2^-- -
_-_^==:^^.;=g^_ ..^
■■ T-^.•^"r■-- ^ ^
~^---^=r^^^^H-- -
I -7^-r-^r.-.-^ ^^-=^... — _-— ^
1
,
-£_^_ -A^_i~£r^""~ "' '"' . ■-"~~^-'-
£?^-i^^^=rr:"--" " — -
H^^^-"^---::3---;_:^:^:^-
-^- _.-'.-:::..-
^78' V
276' 0"
=43 o
30' ti"
32' i"
■< '■".,
6 10"
34' 10"
80 7 '
13' 5'
7 o'
13' 6"
135' 6"
6'o"
132' o"
Total— 1,517 ft
Fig. 3.— Section obtained by bonng with the diamond drill, near Goderlch, Ontario,
Canada, in the Salina series of the Upper Silurian. From a memoir by Dr. Hunt
in the Report of the Geological Survey of Canada for 1876-7.
No. 1, Clay, gravel, and boulders— Post-pliocene. Nos. 2, 4, 7. 9, 13, Dolomite or
magnesian limestone, with layers of marl, limestone, and gypsum. No. 3, Lime-
stone with conxh^—Favosites, etc. Nos. 5, 11, 15, 17. Marls with layers of
Dolomite and anhydrous gypsum. Nos. 6, 8, 10, 12, 14, 16, Rock salt.
G THE CHAIN OF LIFE.
jjioduced by accumulation of corals and shells. Such deposits
must not only have been successive, but must have required
a long time for their formation.
In Fig. 4 we have a bed of coal and its accompaniments.
The coal itself was produced by the slow accumulation of
vegetable matter on a water-soaked soil, and this was buried
!!!
: 4
Fio. 4. — Inclined beds, holding fjssil plants. Carboniferous. S juth Joggins, Nova Scotia»
1. Shale and sandstone. Plants with Spirorbis attached ; rain-marks (?).
2. Sandstone and shale, 8 feet. Erect Calamites. \ An erect c jniferous (?) tree, rooted
3. Gray sandstone, 7 feet. \ on the shale, passes up through 15
4. Gray shale, 4 feet. J feet of the sandstones and shale.
5. Gray sandstone, 4 feet.
6. Gray shale, 6 inches. Prostrate and erect trees, with rootlets, leaves, Naiadiies, and
Spirorbis on the plants.
7. Main coal-seam, 5 feet cjal in two seams.
8. Underclay, with rootlets.
under successive beds of sand and clay, now hardened into
sandstone and shale, some of the beds holding trees and reed-
like plants, which still stand on the soils on which they grew,
and which must have been buried in sediment deposited in
inundations or after subsidence of the land. In this section
we may also observe that the beds are somewhat inclined;
TRELIMINARY CONSIDERATIONS. 7
nnd that this is not their original position is shown by the
posture of the stems of trees, once erect, but now inclined
with the beds. This leads to a consideration very important
with reference to our present subject; namely, that as our con-
tinents are mostly made up of beds deposited under water and
afterwards elevated, these beds have in this process experienced
such disturbances that they rarely retain their horizontal posi-
tion, but are tilted at various angles. When we follow such
inclined strata over large areas, we find that they undulate in
great waves or folds, forming what are called anticlinal and
synclinal lines, and that the irregularities of the surface of the
land depend to a great extent on these undulations, along with
the projection of hard beds whose edges protrude at the sur-
face. In point of fact, as shown in Fig. 5, mountain ranges
depend on these crumplings of the earth's crust; and the
Fig. 5. — Ideal section of the Apalachian Mountains, showing folding of the earth'
crust.
<r, Anticlinal axes. /', Overturned stnita. c, Synclinalb. (f, Unconformable beds.
primary cause of these is probably the shrinkage of the mass
of the earth owing to contraction in cooling. When the dis-
turbances of beds are extreme, they often cause intricacies of
structure difficult to unravel ; but when of moderate extent
they very much aid us in penetrating below the surface, for
we can often see a great thickness of beds rising one from
beneath another, and can thus know by mere superficial ex-
amination the structure of the earth to a great depth. It thus
happens that geologists reckon the thickness of the stratified
:
8 THE CHAIN OF LIFE.
deposits of the crust of the earth at more than 70,000 feet,
though they cannot penetrate it perpendicularly t more than
a fraction of that depth. The two sections, Figs. 6 and 7,
showing the seciuence of beds in luigland and in the northern
part of Nortli America, will serve, if studied by the reader, to
show how, by merely travelling over the surface and measuring
the upturned edges of beds, many thousan:ls of feet of deposits
may be observed, and their relative ages distinctly ascertained.
In studying any extensive section of rock we find that its
members may more or less readily be separated into distinct
groups. Sometimes these are distinguished by what is termed
unconformability, that is, the lower series has been disturbed
or inclined before the upper has been deposited upon it. Tiiis
is seen on a grand scale in the section Fig. 7, in the case 'of
the Laurentian and Cambrian formations, and on a smaller
scale in Fig. 8 in the unconformable superposition of Devonian
conglomerate or Silurian slates at St. Abb's Head. In the last
section it is quite evident that the beds of the lower series
have been bent into abrupt folds and worn away to a con-
siderable extent before the deposition of the overlying series.
In such r :ase we know not merely that the upper series is
newer than the lower, but that some considerable " time must
have elapsed after the deposition of the one before the other
was laid down ; and we are not surprised to find that the
fossils in the groups thus unconformable to each other are very
different.
But even when the beds are conformable, they can usually
be separated into groups, depending upon differences of mineral
charactrer, or changes which have occurred in the mode of
deposition. One group of beds, for example, may be largely
composed of limestone, another of sandstone or shale. One
group may be distinguished by containing some special mineral,
as, for example, rock salt or coal, while others may be destitute
of such special minerals. One group may show by its fossils
that it was deposited in the sea, others may be estuarine or
PRELIMINARY CONSIDERATIONS.
PJ
N'
H>
v»
t
I
r
'
^
i
3
i-»t
V)
E.
P
^
(t
0.
D
r»
n
3
►-•
r»
cr
9
^ ™
:?
OS"
3
< o
r*
o -t»
sr
B _
rt
?• r^
P 3"
f
? 3;
p
c
3
3
5'
3
O"^^
5.H
F 3
p
3
P
0.
S^' a-
P
r*
p
s
rf
*
B'
f»
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t
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3>
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'SJ^^
N..
Cfl
.w
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.o> ;:?
I"
lO
THE CHAIN OF LIFE.
lacustrine. Thus we obtain the means of dividing the rocks
of the earth into groups of different ages, known as " Forma-
tions," and marking particular periods of geological time.
By tracing these formations from one district or region to
another, we learn the further truth that the succession is not
merely local, but that, though liable to variation in detail,
its larger subdivisions hold so extensively that they may be
regarded as world-wide in their distribution.
Putting together the facts thus obtained, we can frame a
tabular arrangement of the earth's strata, as in the table pre-
fixed to this chapter ; and when we add the further discovery,
very early made by geologists, that the successive formations
Fig. 8. — Unconformable superpositi m of Devonian conglomerate on Silurian slates, at
St. Abb's Head, Berwickshire. — After Lyell.
differ from each other in their fossil remains, we have the means
of recognising any particular formation by its fossils, even when
the stratigraphical evidence may be obscure or wanting. Thus
our knowledge of Epochs of Life, and indeed of the whole
geological history of the earth, is based on the superposition
of beds in the earth's crust, and on the diversity of fossil re-
mains in the successive beds so superimposed on each other ;
and it is on these grounds that we are enabled to construct a
Table of Geological Formations representing the whole series
of beds as far as known, with the characteristic groups of fossils
of each period. Here I might close these preliminary con-
siderations, but there are a few accessory questions, important
to our clear comprehension of the subject, which may profitably
occupy our attention for a short time. _
PRELIMINARY CONSIDERATIONS. i|
One of these relates to the absolute duration of the time
represented by the geological history of the earth. Such
estimates as our present knowledge enables us to form are
very indefinite. Whether we seek for astronomical or geo-
logical data, we find great uncertainty. To such an extent is
this the case, that current estimates of the time necessary to
bring the earth from a state of primitive incandescence to its
present condition have vari^i from fifteen millions of years
to five hundred millions. Of the various modes proposed,
perhaps the most satisfactory as well as instructive is that
based on the rate of denudation of our present continents, as
indicated by the amount of sediment carried down by great
rivers. The Mississippi, draining a vast and varied area in
temperate latitudes, is washing away the American land at the
rate of one foot in 6,000 years. The Ganges, in a tropical
climate and draining many mountain valleys, works at the rate
of one foot in 2,358 years. The mean of these two great
rivers would give one foot in 4,179 years, at which rate our
continents would be levelled with the waters in about six
millions of years. But the land has been in process of renewal
•as well as of waste in geological time ; and a better measure
will be afforded by the amount of beds actually deposited.
The entire thickness of all the stratified rocks of Great Britain
has been calculated by Ramsay at 72,000 feet. Now, if we
suppose the waste in all geological time to have been on the
average the same as at present, a* \ that this material has been
deposited to the thickness of 72,000 feet on a belt of sea
margin 100 miles in width, we shall have about 86 millions of
years as the time required.i This has the merit of approxi-
mating to Sir William Thomson's calculation, based on the rate
of cooling of the earth, that a minimum of 100 millions of
years may represent the time since a solid crust first began to
form. As it is more likely that the rate of denudation has on
Croll has elaborated this calculation in his work, C/imafe and Time,
12 THE CHAIN OF LIFE.
the average been greater in former geological periods than at
present, we may perhaps estimate fifty or sixty millions of
years as the time required for t^e accumulation of all our
formations. Some geologists object to this as too little, but in
this some of thev* are influenced by the exigencies of theories
of evolution, and others appear to have no adequate conception
of the vast lapse of time represented by such numbers, in its
relation to the actual rates of denudation and deposition.
If now we attempt to divide this time among the formations
known to us, according to their relative thicknesses, we have,
according to an elaborate estimate of Professor Dana, the time
ratios of 12, 3, and i for the Palaeozoic, Mesozoic, and Cainozoic
periods respectively. Taking the whole time since the begin-
ning of the Cambrian as forty-eight millions of years, we should
thus have for the Palaeozoic thirtv-six millions, for the Mesozoic
nine, and for the Tertiary three. Another calculation, recently
made by Professors Hull and Haughton, gives the following
ratios : —
Azoic 34 "3 per cent.
l^alaeozoic 425 ,,
Mesozoic and Cainozoic . 23 "a ,,
This calculation is, however, based on the absolute thickness of
the several series as ascertained in Great Britain, without re-
ference to the nature of the beds, as indicating different rates
of accumulation. Under either estimate it will be seen that
the Palaeozoic time greatly exceeds the Mesozoic and Caino-
zoic together, and consequently that changes of life seem to
have proceeded at an accelerated rate as time wore on.
Another inquiry of some importance relates to the manner
of preservation of fossils, and the extent to which they consti-
tute the material of rocks. This inquiry is doubly important,
as it bears on the genuineness of fossil remains, and on the
means we have of understanding their nature.
Some rocks are entirely made up of matter that once was
PRELIMINARY CONSIDERATIONS.
13
alive, or formed part of living organisms. This is the case
with some limestones, which consist of microscopic shells, or
of larger shells, corals, and similar calcareous organisms, either
entire or broken into fragments and cemented together with
pasty or crystalline limestone filling their interstices. This
may be seen in Fig. 9, which represents a magnified slice of a
Silurian limestone. Coal in like manner consists of carbonised
^.i^jj^^'
Fig. 9.— Section of Trenton limestone, magnified, showing that it is composed of
fragments of corals, crinoids and shells. Montreal.
vegetable matter, retaining more or less perfectly its organic
structure, and sometimes even the external forms of its consti-
tuent parts. More frequently, fossils are dispersed more or less
sparsely through the substance of beds composed of earthy
matter ; and they have usually been more or less affected by
chemical changes, or by mechanical pressure, or are mineral-
ised by different substances which have either filled their pores
14 THE CHAIN OF LIFE.
by infiltration or have more or less completely replaced their
substance. Of course, as a rule, the softer and more putrescible
organic matters have perished by decay, and it is only the
harder and more resisting parts that remain. Even these have
often yielded to the enormous pressure to which they have
been subjected, and if at all porous, have been changed by the
slow action of percolating water charged with various kinds oi
mineral matter in solution.
It thus happens that many fossils are infiltrated with mineral
matter. Wood, for example, may have the cavities of its cells
and vessels filled with silica or silicates, with sulphide or car-
bonate of iron, or with limestone, while the woody walls of the
cells may remain either as coaly matter or charcoal. I have
often seen the microscopic cells of fossil wood not only filled
in this way, but presenting under a high power successive coats
of deposit, like the banded structure of an agate.
In some cases not only are the pores filled with mineral
matter, but the solid parts themselves have been replaced, and
the whole mass has actually become stone, while still retaining
its original structure. Thus silicified wood is often as hard and
solid as agate, and under the microscope we see that the wood
has entirely perished, and is represented by silica or flint, dif-
fering merely in colour from that which fills the cavities. In
this case we may imagine the wood to have been acted on by
water holding in solution silica, combined with soda or potash,
in the manner of what is termed soluble glass. The wood, in
decay, would be converted into carbon dioxide, and this as
formed would seize on the potash or soda, leaving the silica in
an insoluble state, to be deposited instead of the carbon. Thus
each particle of the carbon of the wood, as removed by decay,
would be replaced by a particle of silica, till the whole be-
came stone. By similar chemical changes corals and shells
are often represented by silica, or by pyrite, which has taken
the place of the original calcareous matter; and still more
remarkable changes sometimes occur, as when the siliceous
PRELIMINARY CONSIDERATIONS.
IS
spicules of sponges have been replaced by carbonate of lime.
The organic matter present in the fossils greatly promotes these
changes, by the substances produced in its decay, and thus it
often happens that the shells, corals, etc., contained in lime-
stone have been replaced by flint, while the in-losing lime-
stone is unchanged. Fig. lo shows the various conditions
which a coral myy assume under these different modes of
treatment.
a
.•I i;
I/I
1
»
I
»
.9
«
5
,litf »
« t • I I
I
t
t
I
♦M»
>•••
ii I I It I
I
< vy/yy/.ii
Fig. io.— Diagram showing different state of
ssilisation of a cell of a tabulate coral
(Dawson's Dawn of Life)
a Natural condition, wall calcite cell empty, b Wall calclte, cells filled with the same.
c Walls calcite, cells filled wuh silica or a silicate, d Wall silicified cells filled
with calcite. e Wall silicified, cell filled w.th silica. siiicmea, cells tilled
The substance of a fossil may be entirely removed by decay
or solution, leaving a mere mould representing its external
form, and this may subsequently be filled with mineral matter,
so as to produce a natural cast of the object. This is very
common in the case of fossil plants; and large trunks of trees
may sometimes be found represented, as seen in Fig. ii, by
stony pillars retaining nothing of the original wood except
perhaps a portion of the bark in the state of coal. It some-
times happens that the substance of fossils has been removed,
leaving mere empty cavities, sometimes containing stony cores*
representing the internal chambers of the fossils. Again, cal-
careous fossils imbedded in hard rocks are often removed by
weathering, leaving very perfect impressions of their forms.
For this reason the fossil remains contained in some hard
i6
THE CHAIN OF LIFE.
. i
h-i
m
resisting rocks can be best seen as impressed moulds on tlie
weathered surfaces.
Lastly, we sometimes have impressions or footprints repre-
senting the locomotion of fossil animals, rather than the fossils
themselves. In this way some extinct creatures are known to
us only by their footsteps on sand or clay, once soft, but now
hardened into stone; and
in the case of some of the
lower animals the trails thus
made are often not easily
interpreted (Figs. 12, 12a).
It has been found that even
sea-weeds drifted by the tide
make impressions of this
kind, which, when they occur
in old rocks, are very mys-
terious. Even rain-drops are
capable of being permanently
impressed on rocks, and con-
stitute a kind of fossils. Be-
sides these we have many
kinds of imitative markings
which simulate fossils, as
those of concretions or no-
dules, which are often very
fantastic in shape, those 01
dendritic crystallisation giv-
ing moss - like forms, and
the complicated tracery pro-
duced on muddy shores by the little rills of water which follow
the receding tide (Fig. 13). Such things are often mistaken
by the ignorant for fossil remains, but are easily distinguished
by a practised eye.
The reader who has followed these, perhaps somewhat dry,
details, will be rewarded for his patience by having some
Fig. II. — Cast of erect tree {Sii^illaria) in
sandstone, standing on a small bed of
coal, South Joggins, Nova Scotia (Daw-
son's Acadian Geology).
PRELIMINARY CONSIDERATIONS.
17
conception of the conditions in which we find fossil remains,
and of the evidence by which we can refer these to different
periods in the history of the earth.
1 if;. 12. — Protichnites septem-notatus. A supposed series of crustacean foot-prints made
in sand, now hardened into sandstone. Cambrian. — ^After Logan.
Carrying this knowledge with us, and at the same time
glancing at the. table of successive formations prefixed to
this chapter, we shall be prepared, without any additional
geological study, to understand the statements to be made in
c
18
THE CHAIN OF LIFE.
the following chapters, and to appreciate the actual nature of
the succession of life in so far as it is at present known.
Fig. 12a.— Footprints of modern Limulus, or king-crab, in the sand, which enable us to
interpret tho!>e in Fig. 12.
Fiu. 13. — Currant markings on shale, resembling a fossil plant,
photograph (Dawson's Acadian Geology).
Reduced from a
Note. — It should have been stated above that, on certain theories
now somewhat generally accepted, respecting the nature and source
of solar heat, the absolute duration of geological time would be much
reduced below the estimate of Sir Wm. Thomson. Prof Tait has based
on such data an estimate of fifteen millions of years. Prof. Simon
Newcomb says that "on the only hypothesis science will now allow
us to make respecting the source of the solar heat" (the gravitation
hypothesis of Helmholtz) "the earth was, twenty millions of years ago,
enveloped in the fiery atmosphere of the sun." Dr. Kirkwood has recently
called attention to these results in connection with the planetary hypothesis
of La Place, in the Proceedings of the American Philosophical Society
(Sept. 1879). Should such views prove to be well founded, geological
calculations as to the time required for the successive formations may have
to be revised.
li
i
1
' I )
i ifl
iJi \}/J: ; \y)
:J
Magnified and Restored Section of a Portion of Eozoon
Canadense.
The shaded portions show the animal matter of the Chambers, Tubuli, Canals,
and Pseudopodia; the unshaded portions the calcareous skeleton.
■I
CHAPTER II.
THE BEGINNING OF LIFE ON THE EARTH.
THE day must have been when the first living being appeared
for the first time on our planet. Was it plant or animal ?
or some generalised organism uniting in some mysterious way
the properties and powers of two kingdoms of nature, now so
distinct, and even contrary to each other in their manifestations ?
Did it appear suddenly, or was it slowly evolved from dead
matter by some process in which the albuminous or proto-
plasmic matter, which we know forms the basal substance of
living beings, was first produced and then endowed with life ?
Did the first living being appear in a mature state, or was it
merely a germ from which the mature individual could be pro-
duced ? These are questions which science in its present state
has no means of answering. We do not know any process by
which the ingredients of protoplasm can be combined so as to
produce that substance without a previous living being. We
do not know what molecular differences may exist between
dead albumen and that which we see growing and moving and
instinct with life; still less do we know how to set up or estab-
lish these differences. We do not know the precise nature or
relation to other forces of the energy which actuates living
organisms. In our experience the simplest creatures that have
life spring from previous germs, themselves the products of
previous generations of living beings. Thus we are in the
li" (
I
iii
Ml!'
P! li
liiii '.L
22 THE CHAIN OF LIFE.
])resence of great mysteries which it might be impossible for us
to solve, even if we were permitted to visit some new planet on
which the dawn of life was breaking.
Some things, however, we can infer as to the conditions of
the introduction of life.
First, there is every reason to believe that the earth we
inhabit was once a glowing, incandescent mass, condensing
from a vaporous condition, and quite unfit for the abode of
living beings, and which, even if in some previous state its
materials had constituted the mass of an inhabited world, must
have lost every trace of any living germ in the fervent heat to
which it had been subjected. There must, therefore, have been
in some way an absolute creation or origination of life and
organisation.
Secondly, we may infer that in the earlier stages of the
earth, when it was perhaps wholly or almost entirely covered
with the waters, when it was still uniformly warmed with its
own internal heat, when it was surrounded with a pall of
dense vapours preventing radiation, and nursing its heat within
itself, though in a condition entirely unsuited to the higher
forms of life, it may have presented circumstances more
favourable to the origination and multiplication of living beings
of low organisation than at any subsequent time. This incu-
bation of creative power in the vaporous mantle over the
primaeval ocean was a favourite imagination of old thinkers,
and is not obscurely hinted at in the book of Genesis. It
has been revived and much insisted on by evolutionists in our
own t'.me, though it has no certain foundation in scientific
observation or experiment.
Thirdly, from the fact that plant-life alone has the power of
subsisting on inorganic matter, and that plants furnish all the
nourishment of animals, we may fairly infer that the life of the
plant preceded that of the animal. It has, indeed, been
suggested that some of the humbler forms of life may combine
in a rude and simple way enough of the powers of the plant
THE BEGINNING OF LIFE ON THE EARTH. 23
and the animal to enable them to bridge over the double gap
between the animal and the plant, and the animal and the
mineral, or that such creatures may in their early stages
carry on vegetable functions, and in their later those of the
animal. It is theoretically possible that life may have begun
with such creatures, which some of the results of micro-
scopical research would lead us to believe still exist. It is,
however, on the whole more probable that simple plants first
existed, and furnished pabulum to animals of low grade intro-
duced almost contemporaneously.
Fourthly, all ou. knowledge of the succession of life leads us
to believe that it was not the higher plants and animals that
first sprang into existence from the teeming earth, but creatures
of low and humble organisation, suited to the then immature
and unfinished condition of the planet. It is also in accordance
with the amazing fecundity of the seas in all geological periods
in these lower forms of life, to suppose that the earliest living
things originated in the waters, and that the plants and animals
of the land are of later date.
Do we know anything from actual observation of this earliest
population of the world ? Such knowledge we can hope to
acquire only by studying the oldest formations known to us ;
and these, it must be confessed, exist in a state so highly crys-
talline, and so much affected by internal heat, by mechanical
pressure, and by movement, as to render it little likely that
organic remains should be preserved in them in a state fit for
recognition.
In many parts of the world, and notably in Canada and
Scandinavia, as well as in Wales, Scotland, and Bavaria, the
older Palaeozoic rocks, the lowest containing plants in great
abundance, rest on still older crystalline beds, which have
j become hard and crystalline in pre- Palaeozoic times, and have
contributed sand and pebbles to the succeeding very ancient
deposits. These old rocks — the Eozoic series of our table — may
be grouped ih two great systems, the Laurentian and Huronian
24 THE CHAIN OF LIFE.
(Fig. 14). The former may be conveniently divided into three
members : First, the Bojian, or Ottawa gneiss, consisting of
stratified granite rocks, usually of a red colour, and of very
great thickness. This contains, so far as known, no limestone,
and has afforded as yet no trace of fossils. Secondly, the
Middle Laurentian, the greater part of which consists of gneiss,
but containing important beds of other rocks, as quartzite, iron
ore, and limestone. It is in this series that we have the first
evidence of life, and it is here also that we find the greatest
abundance of carbon, in ^he form of graphite or plumbago, and
also of calcium phosphate, or bone earth. Thirdly, the Upper
Laurentian or Norian series. This consists in great part of
Labadorite, or lime feldspar, but has also beds of ordinary
gneiss, limestone, and iron ore.
T!.Hl|iAJ.I.|!)JJ, gcrrii e
a b c d
Fig. 14. — Ideal section, showing the relations of the Laurentian and Huronian.
a. Lower Laurentian. h, Middle Laurentiarr. c. Upper Laurentian. d, Huronian.
e, Cambrian and Silurian.
The latter, the Huronian, is much less crystalline, and is
divisible into two series — the Lower Huronian, which includes
many beds of volcanic origin, and the Upper Huronian, which
has afforded some obscure fossils. The Huronian was first
recognised by Sir W. E. Logan in Canada, but corresponding
rocks exist in Europe. The Pebidian series of Hicks in Wales
is probably of this age.
It is likely that much of the present appearance and con-
dition of the most ancient rocks may be attributed to meta-
morphism, that is, to the slow baking under the influence of
heat, heated water, and pressure, to which they have been
subjected in the lower parts of the earth's crust, when buried
deeply under newer deposits. It is also true, however, as
iifii
THE BEGINNING OF LIFE ON THE EARTH. 25
Dr. Sterry Hunt has pointed out in detail, that they present
mineral characters which show a mode of deposition different
from that which has prevailed subsequently, and probably
indicating great ejections of heated mineral matter into the
primitive ocean, and comparatively little of that deposit
therein of mere sand and clay which has prevailed in sub-
sequent geological periods. In short, these rocks have an
unmistakably primitive aspect, distinguishing them from those
of later times, and conveying the impression that they approach
at least to the records of that time when a heated ocean first
rested on the thin and recently solidified crust of our planet.
If this is really the case, then our Lower Laurentian — hard,
compact, destitute of limestone, and composed of material
which may be little else than the debrh of products of internal
heat merely spread out into bedded forms by water — may
represent a time when no living thing as yet tenanted the
waters ; and the dawn of life may have appeared in that period
when the Middle Laurentian beds were laid down. Here at
least we find two kinds of evidence pointing to the existence
of certain forms of life in the waters.
The first depends on the mineral character of the beds
themselves. This formation holds several very thick beds of
limestone. Now although this kind of rock may, under certain
circumstances, 1: i deposited directly from solution in water, it
is not ordinarily so deposited, but more usually through the
agency of living beings inhabiting the waters, and forming
their skeletons or hard parts of limestone derived from the
water, usually through the medium of humble forms of plant
life. In this way are formed reefs of coral and beds of she'ls
and of chalky ooze, all composed of material once constituting
the skeletons of animals. The study of limestones of all
geological ages shows that this has been the usual mode of
their formation. If the Laurentian limestones had a similar
origin, the seas of that period must have swarmed with animals
having calcareous coverings ; and the study of more modern
l:
I it
26 THE CHAIN OF LIFE.
limestones which have become highly crystalline shows that it
is quite possible that the forms and structures of these organisms
may have been obliterated.
Again, the Middle Laurentian abounds in carbon or coaly
matter. True, this is in the form of graphite or plumbago,
but this may be a result of metamorphism j and we
know that the carbon of coal-beds and bituminous shales of
much more modern times has been altered into graphite.
Further, the graphite occurs in the way in which we should
expect it to occur if of organic origin. It is found dissemi-
nated in the limestone, just as bituminous matter is found in
unaltered rocks of this kind. It xs found interlaminated with
gneiss, as carbonaceous and bituminous matters are found in
the shales of the ordinary fossiliferous rocks, where these
substances are known to be of organic origin. The graphite
also occurs in a very pure form in irregular veins, just as in
some bituminous formations the rock oil, oozing into fissures,
has been hardened into asphalt or coaly matter.^
To these facts may be added the presence of thick beds
and veins of iron ore and of apatite or calcium phosphate
(bone earth). Both of these substances occur in a dis-
seminated state in nearly all rocks, but they are concen-
trated into definite deposits by the action of life. Iron is
usually dissolved out and redeposited by acids produced in
the decay of vegetable matter, as we see in the clay iron-
stones of the coal formation and in bog-iron ores. Calcic
phosphate is taken up by many animals, and forms their shells
or skeletons, and is deposited on their death in beds on the
sea-bottom, sometimes to a very considerable extent.
The concurrence of all these phenomena in the Middle
^ Analyses recently made by Mr. C. Hoffman, of the Geological Survey
of Canada, show that beds of graphitic gneiss, some of them 8 feet in
thickness, contain as mnch as 25*5 to 30 per cent, of carbon, the remaining
earthy matter consisting principally of silica, alumina, and lime. The
graphite from veins was nearly pure carbon, containing from 97*6 to 99*8
per cent, of that substance.
THE BEGINNING OF LIFE ON THE EARTH. 27
Laurentian may be held to afford a strong presumption that,
could we discover these rocks in an unaltered state, we should
find the limestones filled with marine fossils and the graphite
showing the forms or presence of plants. The only startling
feature in this conclusion is, that if we admit it, we must
also admit that life was developed in the Laurentian time in
an exuberance not surpassed, if equalled, in any subse-
quent period. Still, there is nothing incredible in this, for
if the forms of life were few and low, their increase may
have been rapid, because unchecked ; and they no doubt
found in the ancient seas a surplusage of material on which
to feed and with which to construct their skeletons. Dr.
Hunt has estimated that the amount of carbon now sealed up
as coaly matter would, if diffused in the atmosphere as carbon
dioxide, afford 600 times the quantity of that gas at present
floating in the air. A still more vast amount is sealed up in
the limestone of the several geological formations. The same
chemist has shown that the quantity of lime held in solution
in the ocean must have been much greater in Laurentian times
than at present. These facts at least allow us to suppose that
in the Eozoic times there were great supplies of carbon and of
lime available to such creatures of low organisation as were
capable of profiting by them ; and we have no reason to doubt
that there may have been plants and animals so constituted as
to flourish in conditions of this kind, in which perhaps scarcely
any modern species could exist.
These probabilities have caused geologists anxiously to
search for any traces of fossil organic remains in the old
Laurentian rocks ; and they have been rewarded by the dis-
covery of one species, Eozoon Canadense, still often referred to
as only a problematical fossil ; but this arises to a large extent
from the prevalent want of knowledge sufficient to appreciate
the evidence for its organic character. This being once
admitted, we have in the existence of Eozoon alone a suffi-
cient cause for the accumulation of much of the Laurentian
i8
THE CHAIN OF LIFE.
limestone, though there is reason to believe that it was not
the only inhabitant of those ancient seas.
The best specimens of Eozoon occur as rounded, flattened,
or more or less irregular lumps or masses in certain layers of
the Laurentian limestone. When weathered on the surface
Fig. 15 (Nos. 1 to 4). — Small weathered specimen of Eozoon. From Petite Nation.
T, Natural size; showing general form, and acervuline portion above and laminated
portion below. 2, Enlarged casts of cells from upper part. 3, Enlarged casts of
cells from the lower part of the acervuline portion. 4, Enlarged casts of sarcode layers
from the laminated part.
of the rock, these lumps show a regular concentric lamina-
tion, caused by thin fibres of limestone, alternating with other
mineral substances, filling up the spaces between them. When
these intervening layers are composed of such minerals as
Serpentine, Loganite, Pyroxene, or Dolomite, which are more
THE BEGINNING OF LIFE ON THE EARTH. 29
resisting than the limestone, they project when weathered, or
when the limestone is etched by an acid, so as to show the
lamination very distinctly. At the lower surface of the masses
the layers are seen to be thicker than they are above, and in
perfect specimens they are seen toward the surface to break up
Fig. 16. — Nature-printed specimen of Eozocn slightly etched with acid. It shows the
lamination, and at one side fragmental Eozoon {Life's Daivn on Earth).
into small rounded vesicles of calcite, like little bubbles, which
constitute the so-called acervuline condition of Eozoon (Fig.
15, No. 2). Slices of the fossil etched with an acid show
these appearances very perfectly, and can even be printed
from, so as to present perfect nature-prints of the structure
(Fig. 16).
On etching a small fragment or slice with very dilute acid,
30 THE CHAIN OF LIFE.
so as to dissolve away the calcite slowly, if the specimen be
well preserved, we find that the calcite layers have a very
curious structure. This is indicated by the appearance of
little white or transparent threads of Serpentine, Dolomite,
or Pyroxene, which ramify throughout the substance of the
limestone layers, and are left intact when they have been
dissolved. These little processes must originally have been
pores in the limestone layers, which have been filled with
the substance which constitutes the alternate laminae. In
addition to this, if we use a somewhat high microscopic power,
and especially if we study the structures as seen in thin trans-
parent slices, we can perceive a still finer tubulation along the
sides of the calcite layers, represented by extremely minute
parallel rods of mineral matter (Figs. 17, i8).
Now if we regard these structures as those of an infiltrated
fossil, as described in last chapter, their interpretation will not
be difficult. The original organism was composed of calcareous
matter in thin concentric laminae, connected with each other
by pillars and plates of similar material. Between these
laminae was lodged the soft, jelly-like substance of a marine
animal, growing by the addition of successive layers, each pro-
tected by a thin calcareous crust. The layers were originally
traversed by very numerous parallel tubuli, permitting the soft
protoplasm to penetrate them ; and when, in the progress of
growth, it was necessary to strengthen these layers, they were
thickened by a supplemental deposit traversed by larger and
ramifying canals. When the animal was dead, and its soft parts
removed by decay, the chambers between the laminae, as
well as the minute canals and tubuli, became infiltrated with
mineral matter, in the manner described in the last chapter,
and when so preserved became absolutely imperishable under
any. circumstances short of absolute fusion.
This interpretation leads to the conclusion, at which I arrived
from the study of the first well-preserved specimen ever
submitted to microscopic examination, that the animal which
THE BEGINNING OF LIFE ON THE EARTH. 31
Fig. 17. — Magnified group of canals in supplemental skeleton of Eozoon.
Taken from the specimen in which they were first recognised {Life's Dawn on Earth).
Fig. 18. — Portion of Eozoon magnified loo diameters, showing the original cell-wall with
tabulation, and the supplemental skeleton with canals. — After Carpenter.
a. Original tubulated wall or"Nummuline layer." More magnified in Fig. A. b, c.
Intermediate skeleton, with canals.
32
THE CHAIN OF LIFE.
produced the calcareous skeleton of Eozoon was a ttiember of
that lowest grade of Protozoa known as Foraminifera; and which,
after living through the whole of geological time, still abound
in the sea. The main differences are, that Eozoon presents
a 'somewhat generalised structure, intermediate between two
modern types, and that it attained to a gigantic size compared
with most of these organisms in later periods. How near it
approaches in structure to some modern forms may be seen by
comparison of the recent species represented in Fig. 19
in
Fic;. 19. — Magnified portion of shell of Calcarina — ^After Carpenter.
a. Cells. /', Original cell-wall with tiibull. c, Supplementary skelatcn with canal-;
which the parts corresponding to the chambers, laminae, tubuli,
and canals of Eozoon can be readily distinguished.
The modern animals of this group are wholly composed of
soft gelatinous protoplasm or sarcode, the outer layer of which
is usually somewhat denser than the inner portion ; but both are
structureless, except that the inner layer may present a more
THE BEGINNING OF LIFE ON THE EARTH. 33
or less distinct granular appearance. Many of them show a
distinct spot or cell, called the nucleus, and some have minute
transparent vesicles, which contract and expand alternately,
and appear to be of the nature of circulatory or excretory
organs. They have no proper alimentary canal, but receive
their food into the general mass and digest it in temporary
cavities. Their means of locomotion and prehension are
soft thread-like or finger-like processes, extended at will
from the surface of any part of the body, and known as
false feet (pseudopodia). From these processes the whole
group has obtained the name of Rhizopods, or root-footed
animals. They may be regarded as constituting the simplest
and humblest form of animal life certainly known to us.
The very numerous species of these creatures existing in the
waters of the modern world may be arranged under three prin-
cipal groups. The first and highest includes those which have
lobate or finger- like pseudopods, and a well-developed nucleus
and pulsating vesicle (Fig. 20, a). They are mostly inhabit-
ants of fresh water, and destitute of a hard crust or shell. A
second group, including many inhabitants of the sea as well as
of fresh waters, has thread-like radiating pseudopodia 1 (Fig.
20 b). Some of these form beautiful silicious skeletons. A
third group, essentially marine, consists of those with reticulated
pseudopodia, and usually destitute of distinct nucleus and pul-
sating vesicle (Fig. 21). They produce beautiful calcareous
skeletons, often very complex, or sometimes are content to
cover themselves with a crust of agglutinated grains of sand.
It is to this last group that Eozoon belongs, and to the highest
division of it — that which has the shell perforated with minute
pores, often of two kinds. It is curious that just as we have
the chambers and pores of Eozoon filled with serpentine,
so in all geological formations and in the modern seas it
is not uncommon to find Foraminifera having their cavities
* Sometimes separated as a dii;tinct order under the name of Radiolaria.
34
THE CHAIN OF LIFE.
filled with glauconite and other hydrous silicates allied to
serpentine.
Fig. 20. — a. Amoeba, a fresh-water naked Rhiatopod ; and b, Actino^htys. a. fresh-water
Protozoon of the group Radiolaria, with thread-like pseudopodia.
(l\Vl^v
Fig. 21. — Nonionina, a modern marine Foraminifer. Showing its chambered shell and
netted pseudopodia. — After Carpenter.
If we attempt to trace the Rhizopods onward from the Middle
Laurentian, we are met with a great hiatus in the Upper Lauren-
THE BEGINNING OF LIFE ON THE EARTH. 35
tian. The species Eozoon Bavaricwn has, however, been
found in rocks apparently of Huronian age ; but this is the last
known appearance of Eozoon, properly so-called. In the
Cambrian or Siluro-Cambrian, however, we meet with many
gigantic Protozoa, more especially those ,vnovvn as Stromatopora ^
ArchcBocyathuSy and Receptaadites.
The typical Stromatoporae, or Layer-corals, consist, like
Fig. 2a. — Stromatopora concetitrica. — ^After Hall.
a. Section of the same, magnified, b. Small portion highly magnified, showing lamina:
and pillars.
Eozoon, of concentric layers, connected by numerous pillars,
which are often, though not always, more definite and regular
than in the Laurentian fossil. The laminae are perforated, but
more coarsely than in Eozoon, and they are often thickened with
supplemental deposit which, in some of the forms, presents canals
radiating from vertical tubes or bundles of tubes penetrating
the mass (Figs. 22, 23). The mode of growth of Stromatopora
must have precisely resembled that of Eozoon, and the forms
D 2
36
THE CHAIN OF LIFE.
l)roduced are so similar that it is oft'»n quite impossible to dis-
tinguish them by the naked eye. Like Eozoon, they form the
substance of important limestones, and single masses are some-
times found as much as three feet in diameter. The Stromato-
porce extend through the Silurian into the Devonian. In the
Carboniferous they are continued by smaller and more regular
organisms of the genus Lofttisia^ and this genus seems to
extend without marked change up to the Eocene Tertiary. In
modern times I know of no nearer representative than the
animal whose skeleton often adheres in red encrusting patches
to our specimens of corals, and which is known as Polytrema^
Fig. i-^.-^Caunopora planulata. Showing the radiating canals on a weathered
surface. Devonian. — After Hall.
In general structure it is not very far from being a very
degenerate kind of Stromatopora.
It is curious that ' ' the line of succession above stated, the
beautiful tubulat'^ wall of Eozoon disappears; and this
structure see'' ^ the Laurentian, to be for ever divorced
from the grt aminated Protozoans. It reappears in the
Carboniferous, in certain smaller organisms of the typ^ of the
Nummulites, or Money-stone Foraminifers, and is continued in
this group of smaller and free animals down to the present time.
In the Cretaceous and early Tertiary periods, the Foraminifera
^ Loftusia Columbiana^ Dawson, from British Columbia, is the only
Carboniferous species yet known.
THE BEGINNING OF LIFE ON THE EARTH. 37
of different types have been nearly as great rock builders
as they were in the Laurentian. Some of these later roclc-
builders, however, have belonged to the lower or imperforate
group ; others to the higher or Rotaline and Nummuline groups ;
and, as a whole, they have been individually small, making up
in numbers what they lacked in size. Probably the conditions
for enabling animals of this type rapidly, and on a large scale,
Fig. 24. — Arc/tceocyathtis minganenst's. A Primo; Hal Protoz;on.— After Billings.
a Pores of the inner wall.
to collect calcareous matter, were more favourable in the
Laurentian than they have ever been since.
In the Siluro-Cambrian age two other forms of gigantic
Foraminiferal Protozoans were introduced, widely different from
Eozoon, and destined apparently not to survive the period in
which they appeared. These were Archaeocyathus, the ancient
Cup-corals, and Receptaoulites, which may perhaps be called
38 THE CHAIN OF LIFE.
the Sack -corals. Both are quite remote from Eozoon in
structure, wanting its complexity in the matter of minute
tubules, and having greater regularity and complication on the
large scale. Archaeocyathus had the form of a hollow inverted
cone with double perforated walls, connected by radiating
irregular plates, also perforated (Fig. 24). It has been re-
garded as a sporge, and some species are certainly accompanied
with spicules ; but these seem to be merely accidental, and will
Fig. 25.— ReceptacuUtes. Restored.— After Billings.
it. Aperture. /;, Inner wall, c. Outer wall, n, Nucleus, cr primarj' chamber.
V, Internal cavity.
be referred to in the next chapter. Archaeocyathus came in with
the Later Cambrian, and seems to have died out in the Siluro-
Cambrian. The only more modern things which at all resemble
it are ;he Foraminifera called Dactylopora, which belong to the
Tertiary period.
ReceptacuUtes is a still more complex organism. It has a
sack-like form, often attaining a large size, and the double
walls are composed of square or rhombic plates, connected
THE BEGINNING OF LIFE ON THE EARTH. 39
with each other by hollow tubes from which proceed canals
perforating the plates (Fig. 25). This curious structure is
confined to the Siluro-Cambrian, and is so dissimilar from
modern forms that its affinities have been subject to grave
doubts.
We thus have presented to us the remarkable fact that in
the Palaeozoic age we have no precise representative of Eozoon,
but instead three divergent types, differing from it and from
Fig. 26.— Section of Lofttisia Persica. An Eocene Foraminifer allied to Stromatopora.
Magnified five diameters,— After Carpenter and Brady.
each other, all apparently specialised to particular uses, all
tempon.jy in their duration ; while in later times nature seems
to have returned nearer to the type of Eozoon, though on a
smalle*- scale, and separating some characters conjoined in it.
Some portion of this curious result may be due to our ignorance ;
and it would be interesting to know, what we may know some
day, how this type of life was represented in the long interval
between the Huronian { nd the Upper Cambrian, when perhaps
40 THE CHAIN OF LIFE.
there may have been forms that would at least enable us to
connect Eozoon and Stromatopora.
Another link in the chain of being remains to be noticed
here. In the Laurentian limestones we meet with numerous
minute spherical bodies and groups of spheres with calcareous
tubulated tests. ^ These may either be small Foraminiferae,
distinct from Eozoon, or may be germs or detached cells from
its surface. Similar bodies are found in the lower part of the
Siluro-Cambrian, in the Quebec group at Point Levis ; and there
they are filled with a species of glauconite constituting a sort of
greensand rock. Still higher, in the Carboniferous, there are
very numerous species of Foraminifera, presenting forms very
similar to those of the modern seas, so that in the smaller
shells of this group we seem to have evidence of a continuous
series all the way from the Laurentian to the present time. The
greater laminated forms cc-exist with these up to the I^pcene
Tertiary. Throughout the whole of geological time — from the
formation of the Laurentian Hmestones to that of the chalky
ooze accumulating in the modern ocean — these humble creatures
have been among the chief instruments in seizing on the
calcareous matter of the waters and depositing it in the form of
limestone.
I have, said nothing of the development of higher forms of
animal life from Eozoon, simply because I know nothing of it.
We shall see in the next chapter that these are introduced
seemingly in an independent manner. We may be content to
trace foraminiferal life along its own line of development,
waxing and waning, but ever confined within the same general
boundaries, from the Laurentian to the present time. It is
likely that if, in any of the ages constituting this vast lapse of
time, a dredge had oeen dropped into the depths of ocean,
it would have brought up Foraminifera not essentially different in
form and structure. If any one asks to what extent the suc-
cessive species constituting this almost endless chain may be
^ ArchcBospherina of the author.
THE BEGINNING OF LIFE ON THE EARTH. 41
descendants one of the other, we have no absolutely certain
information to give. On the one hand, it is not inconceivable
that such forms as Stromatopora or Nummulina may have de-
scended from Eozoon. On the other hand, it is equally con-
ceivable that the same power which produced Eozoon at first,
whether from dead matter or from some unk^- own lower form
Fig. 27. — Foraminiftral Rock Builders, in the Cretaceous and Eocene.
a, Ntimniulites iarvi^ata—Koceue. b. The same, showing chambered interirr. c,
MilioUne hmestone, magnified— Eocene, Pans, d, Hard Chalk, section magnitied—
Cretaceous.
of life, may have repeated the process in later times with
modifications. In any case it is probable that the Foraminifera
have experienced alternations v ' expansion and shrinkage, of
elevation and decadence, in the lapse of geological time.
There were times in which many new forms swarmed into ex-
istence, and times in which old forms were becoming extinct
42
THE CHAIN OF LIFE.
without being replaced by others. In so far as the areas of
the continents and the adjacent waters are concerned, those
periods when the land was subsiding under the ocean must
have been their times of prosperity, those in which the crust
of the earth shrunk and raised up large areas of land must
have been their times of decay. Still this lowest form of animal
life has never perished, but has always found abundant place
for itself, however pressed by physical change and by the
introduction of higher beings.
A Camukian Trilobite. Paradoxidcs vtkitiac (Hartt).
Restored by G. H. Matthews.
J
CHAPTER III.
THE AGE OF INVERTEBRATES OF THE SEA.
IF the middle portion of the Laurentian age was really a time
of exuberant and abounding life, either this met with
strange reverses in succeeding periods, or the conditions of
preservation have been such as to prevent us from tracing its
onward history. Certain it is, that according to present ap-
pearances we have a new beginning in the Cambrian, which
introduces the great Paljeozoic age, and few links of connection
are known between this and the previous Eozoic.
At the beginning of the Palaeozoic we have reason to be-
lieve that our continents were slowly subsiding under the sea,
after a period of general continental elevation which was con-
sequent on the crumplin.s: of the earth's crust at the close of
the Eozoic ; and on the new sea-bottoms formed by this subsi-
dence came in, slowly at first, but in ever-increasing swarms,
the abundant and varied life of the early Palaeozoic.
In the oldest portion of the Cambrian series in Wales, Hicks
has catalogued species of no less than seventeen genera, em-
bracing Crustaceans, the representatives of our crabs and lob-
sters, bivalve and univalve shell-fishes of different types, worms,
sea-stars, zoophytes, and sponges. If we could have walked
on the shores of the old Cambrian sea, or cast our dredge or
trawl into its depths, we should have found representatives of
most of the humbler forms of sea life still extant, though of
46
THE CHAIN OF LIFE.
specific forms strange to us. Perhaps the nearest approach to
such experience which we can make is to examine the group of
Cambrian animals delineated in Fig. 28, and to notice, under
the guidance of the geologist above named, the sections seen
at St. David's, in South Wales.
Here we find a nucleus of ancient rocks supposed to be
Laurentian, though in mineral character more nearly akin to
Fig. 28.— Group of Cambrian Animals (from Nicholson).
a, ArcnicoUtes didymus, worm-tubes, b, Lingulella femtginea. c, Thcca Da7<idii.
d, Modiolopsis solvensis. e, Orthis Hicksii. /, Obolella sagittalis. g, Hymcn-
ocaris vermicauda. h, TrilobLte, Olenus micrurtts.
the Huronian, but which have hitherto afforded no trace of
fossils. Resting unconformably on these is a series of par-
tially altered rocks, regarded as Lower Cambrian, and also
destitute of organic remains. These have a thickness of al-
most 1,000 feet, and they are succeeded by 3,000 feet more
of similar rocks, still classed as Lower Cambrian, but which
have afforded fossils. The lowest bed which contains indica-
tions of life is a red shale, perhaps a deep-sea bed, and possibly
THE AGE OF INVERTEBRATES OF THE SEA. 47
itselt partly of organic origin, by that strange process of de-
composition or dissolution of foraminiferal ooze and volcanic
fragments, going on in the depths of the modern ocean, and
described by Dr. Wyville Thomson as occurring over large
areas in the South Pacific. The species are two Lingidellic, a
Discina and a Leperditia. Supposing these to be all, it is re-
markable that we have no Protozoa or Corals or Echinoderms,
and that the types of Brachiopods and Crustaceans are of com-
paratively modern affinities. Passing upward through another
1,000 feet of barren sandstone, we reach a zone in which no
less than five genera of Trilobites are found, along with Ptero-
pods and a sponge. Thus it is that life comes in at the base
of the Cambrian in Wales, and it may be regarded as a fair
specimen of the facts as they appear in the earlier fossiliferous
beds succeeding the Laurentian. Taking the first of these
groups of fossils, we may recognise in the Leperditia a two-
valved Crustacean closely allied to forms still living in the seas
and fresh waters. The Lingulellae, whether we regard them as
molluscoids, or, with Professor Morse, as singularly specialised
worms, represent a peculiar and distinct type, handed down,
through all the vicissitudes of the geological ages, to the pre-
sent day. The Pteropods and the sponge are very similar to
forms now living. The Trilobites are an extinct group, but
closely allied to some modern Crustaceans. Had the pri-
mordial life begun with species altogether inscrutable and
unexampled in succeeding ages, this would no doubt have
been mysterious ; but next to this is the mystery ot the oldest
fc-ms of life being also among the pewest. Whatever the
origin of these creatures, they represent families which have
endured till now in the struggle for existence without either
elevation or degradation. Yet, though thus vast in their
duration, they seem to have swarmed in together and in great
numbers, in the Cambrian, without any previous preparation.
From the Cambrian onward, throughout the whole Palaeozoic,
there is no decided break in the continuity of marine life ; and
48 THE CHAIN OF LIFE.
already in the Silurian period the sea was tenanted with all the
forms of invertebrate life it yet presents, and these in a teeming
abundance not surpassed in any succeeding age. Let us now,
in accordance with our plan, select some of these ancient
inhabitants of the waters and trace their subsequent history.
Remains of sea-weeds are undoubtedly present in the Cam-
brian rocks. One of the lowest beds in Sweden has been
named from their abundance the Fucoidal Sandstone ; and
wherever fossiliferous Cambrian rocks occur, some traces, more
or less obscure, of these plants may be found. Nearly all that
we can say of them, however, is, that, in so far as their remains
give any information, they are very like the plants of the same
group that now abound in our seas. In the fucoidal sandstone
of Sweden certain striated or ribbed bodies have been found,
which have even been regarded as land plants ; ^ but they seem
rather to be trails or marks left by sea-weeds dragged by cur-
rents over a muddy bottom. The plants of the sea thus
precede those of the land, and they begin on the same level
as to structure that they have since maintained.
The Foraminifera of the Palaeozoic we have noticed in the
last chapter ; but we now find a new type of Protozoan — that
of the Sponge. Sponges as they exist at present may be de-
fined to be composite animals, made up of a great number of
one-celled or gelatinous zoids, provided with vibrating threads
or cilia, and so arranged that currents of water are driven
through passages or canals in the mass, by the action of the
cilia, bringing food and aerated water for respiration. To
support these soft sarcodic sponge-masses, they secrete fibres
of horny matter and needles (spiculae) of flint or of limestone,
forming complicated fibrous and spicular skeletons, often of
great beauty. They abound in all seas, and some species are
found in fresh waters.
With the exception of a very few species destitute of skele-
ton, and which we cannot expect to find in a fossil state, the
^ Eophyton Linnaanum (Torrell).
i
THE AGE OF INVERTEBRATES OF THE SEA. 49
sponges may be roughly divided into three groups : 1, those
with corneous or horny skeleton, like our common washing
sponges; 2, those with skeletons composed of silicious
needles of various forms and arrangement; 3, those with
calcareous spicules. Of these, the second or silicious group
has precedence in point of time, beginning in the Early Cam-
brian, and continuing to the present. Two of its subdivisions
are especially interesting in their range. The first is that of
the Lattice-sponges {Hexactinellidce), in vhich the spicules have
Fig. 2g. — Portion of skeleton of Hetactinpllid Sponge {Caeloftychium). Magnified.
After Zittel.
six rays placed at right angles, and are attached to each other
by their points, so as to form a very regular network (Fig. 29).
The second is that of the Stone-sponges {LithisfidcB), in which
the spicules are four-rayed or irregular, and are united by the
branching root-like ends of the rays. The most beautiful of all
sponges, the Venus Flower-basket {Euplectelld)^ is a modern
E
so
THE CHAIN OF LIFE.
Hexactinellid, and the wonderful weaving of its spicules is as
marvellous a triumph of constructive skill as its general form
is graceful. The Lithistids are less beautiful, but are the
densest and most compact of sponges, and are represented
by several species in the modern seas. Both of these types
go back to the Early Cambrian, and have continued side by
side to the present day, as representatives of two distinct geo-
metrical methods for the construction of a spicular skeleton.
Many years ago the keen eye of thj late lamented Salter
detected in a stain on the surface of a slab of Cambrian slate
the remains of a sponge ; and minute examination showed that
its spicules crossed each other, and formed lattice-work on the
Fig. 30.- /'rtf/£jj/£7«^/Vty<^«<'s^rrt/rt (Salter). Menevian group. «, Fragment showing the
spicules partially displaced, i, Portion enlarged.
hexactinellid plan. Salter boldly named it Protospongia (the
first sponge), and it is still the earliest that we know (Fig.
30). Thus the type whose skeleton is the most perfect in a
mechanical point of view takes the lead. It is continued in
the Silurian in many curious forms, of which the stalkless
sponges (Astylospongia) are the most common (Fig. 31). It
perhaps attains its maximum in the Cretaceous, from which the
beautiful example in Fig. 29 is taken, and it still flourishes,
giving us the most beautiful of all recent forms. Before the
expiration of the Cambrian there were other sponges of the
Lithistid type. Fig. 32 represents a group of spicules from
the Calciferous (Lowest Silurian or Upper Cambrian) of
THE AGE OF INVERTEBRATES OF THE SEA. $i
Mingan,^ and which probably belong to a large I.ithistid sponge
of that early time. The Lithistids have been recognised in the
Fio. 31. — Astylospongia pyamorsa (Roemer). Niagara group. —After Hall.
a. Spicules magnified.
Upper Silurian and Carboniferous, and continuing upward to
the Cretaceous, these become vastly numerous, while their
Fig. 32. — Spicules of Lithistid sponge {Trichospotigta of Billings). From the Cambrian
of Labrador.
modern representatives are by no means few. The silicious
sponges with simple spicules appear to have existed as far back
as the Carboniferous, and there is believed to be still earlier
^ They probably belong to a large sponge named by Billings Tricho-
spongia sericea.
E 2
52
THE CHAIN OF LIFE.
evidence of horny or corneous sponges.^ The calcareous
sponges have been recognised as far back as the Silurian.^
Thus from the close of the Palaeozoic all the types of sponges
seem to have existed side by side ; and in the Cretaceous period,
when such large areas of our continents were deeply submerged,
they attained a wonderful development, perhaps not equalled
in any other era of the earth's history.
Fig. -^-i. — Oldhaniia antiqua
(Forbes).
Fig. 34. — Dictyonetna sociale. Enlarged.
Lingula flags. — After Salter.
Sponges may be regarded as the highest or most complex of
the Protozoa. We have no links wherewith to connect them
with the lower Protozoa of the Eozoic period ; and through
their long history, though very numerous in genera and species,
they show no closer relationship with the Foraminifera below,
and the Corals above, than do their successors in the modern
seas. They thus stand very much apart ; and modern studies
^i their development and minute structures do not seem to
remove them from this isolation. Though we are treating
here of inhabitants of the sea, it may be proper to mention
^ Protospongia (Salter). ^ Amphispongia,
THE AGE OF INVERTEBRATES OF THE SEA. S3
that Geinitz has described two species from the Permian which
he believed to be early precursors of the Spongillae, or fresh-
water spopges ; but more recently he seems to regard them
as probably Algae. Young has, however, recently found true
spicules of Spongilla in the Purbeck beds.^
A stage higher than the sponges are those little polyp-like
animals with sac-like bodies and radiating arms or tentacles,
which form minute horny c- calcareous cells, and bud out into
branching communities, looking to untrained eyes like delicate
sea-weeds — the sea-firs and sea-mosses of our coasts (Fig. 36).
These belong to a very old group, for in the oldest Cambrian
we have a form referred to this type (Fig. 33), and in the
Fig, 2,l.—Dictyonemn IVeisieri (T)n). Niagara formation.
a. Enlarged portion {Acadian Geology).
Upper Cambrian another still more decided example (Fig.
34).2 This style of life, once introduced, must have increased
in variety and extended itself with amazing rapidity, for in the
Siluro-Cambrian age we find it already as characteristic as in
our modern seas, and so abundant that vast thicknesses of
shale are filled and blackened with the debris of forms allied
to the sea-firs, and masses of limestone largely made up of the
more calcareous forms of the sea-mosses. As examples of the
former we may take the Graptolites, so named from their re-
semblance to lines of writing, and of which several forms
1 Geological Magazine, ■'^'", 1878.
^ It is regarded as sonk;^./bat doubtful whether these a-? Ilydroids or
Bryozoa.
I!
I>
1 1
54
THE CHAIN OF LIFE.
are represented in Fig. 37. The little teeth on the sides of
these were cells, inhabited probably by polyps, like those repre-
sented in the modern Sertularia in Fig. 36. Some of them
were probably attached to the bottom. In others the branches
radiated from a central film, as in Fig. 38, which may have
been a hollow vesicle or float, enabling them to live at the
surface of the water. These Graptolites are specially character-
istic of the Upper Cambrian and Lower Silurian. The netted
Fig. 36. —Group of modem Hydroids allied to Graptolites. Magnified, and natural size.
a, Sertularia, b, Tubttlaria. c, Campaniilaria.
ones {Dictyonema), as may be seen from Figs. 34 and 35, came
in before the close of the Cambrian, and continue unchanged
to the Upper Silurian, where they disappear. The branching
forms, seen in Fig. 37, have scarcely so great a range. They
thus form most certain marks of the period to which they
belong, and being oceanic and prcbably floaters, they diffused
^themselves so rapidly that they appear to indicate the same
geological time in countries so widely separated as Europe,
i
THE AGE OF INVERTEBRATES OF THE SEA. 55
North America, and Australia. It is curious, too, that while
[he Graptolites thus mark a definite geological time, and seem
to disappear abruptly and without apparent cause, they are the
I
a.
Fig. 37. — Silurian Grapt.litida.
a, Grapiolithus. b, Diplogmpsm. c. Phyllo^rapsus. d, Tetragrapsus.
e, Dtdymograpsus.
first link in the long chain of the Hydroids, which, though
under different family forms, continue to this day, apparently
neither better nor worse than their perished Palaeozoic relatives.
F,0.38^Central portion of Grap^-;lite, F.o. 39--^^ ^£^'^^^ -M^ ^^V-
with membrane, or fljat (Dic/w- •*"•"'■ *-
grapsus octobrachiatus, Hall).
There is a group of little Stony Corals {Chaetetes\ which were
possibly also the cells of Hydroids, that have a similar history.
They are the only known Corals that date so far back as the
56
THE CHAIN OF LIFE.
Upper Cambrian ; and they continue under very similar forms
all through the Palaeozoic, and are represented by the millepore
.^'h,.-
l^Avk^
Fig. 39rt. — Fenestella LyelU {Da.vison). A Carb:.niferous Bryozoan.
corals of the present day. Fig. 40 represents a form found at
the base of the Siluro-Cambrian, and Fig. 41 shows forms
characteristic of the Carboniferous Lime-
stone.
If we turn now to the sea-mosses (Bryozoa),
we have a group of minute polyp-like animals
inhabiting cells not unlike those of the Hy
droids, and which form plant-like aggregates.
But the animals themselves are so different
in structure that they are considered to be
nearer allies of the bivalve shell-fishes than
of the Corals. They are, in short, so different,
that the most ardent evolutionist would
scarcely hold a community of origin between
them and such creatures as the Graptolites and
Millepores, though an ordinary observer might readily confound
the one with the other. These animals appear at the beginning
of the Siluro-Cambrian, and such forms as that represented in
Fig. 39, very closely allied to some now living, are large consti-
tuents of some of the limestones of that period. Other forms,
Fig. 40. — Chaetetes
fibrosa. A tabulate
coral with micro-
scopic cells. Ljwer
bilurian.
I
^
THE AGE OF INVERTEBRATES OF THE SEA. $7
like that represented in Fig. 39^, are very characteristic of the
Carboniferous. These animals, individually small, though com-
plicated in structure and branching into communities, scarcely
ever of any great magnitude, humble creatures which have
never played any great part in the world, have, nevertheless,
been so persistent that, though specific and generic forms have
been changed, the group may be said to be in the modern seas
exactly what it was in those of the early Palaeozoic, nor can it
be affirmed to have originated in anything different, or to have
produced anything.
The true Stony Corals (A n//iozoa) are as yet unknown in the
Fig. 41.— a, Stetiopora exi/is (Dawson), b, Chaetetes Unnidiisi^Awz.tA% and Haine).
Carboniferous.
Cambrian. They entered on the stage in immense abundance
in the Siluro -Cambrian, where considerable limestones are
largely composed of their remains, mixed, however, and some-
times overpowered with those of Bryozoa and Hydroids. An
ordinary coral, such as those of which coral reefs are built —
the red coral used for ornament is not quite similar — is the
skeleton of an animal constructed on the plan of a sea anemone ;
with a central stomach surrounded by radiating chambers, and
having above a crown of tentacles. The stony coral sur-
rounds and protects the soft body of the animal, and may
either be a single cell, for one animal, or an aggregation of
such cells, constituting; a rounded or branching mass. The
58 THE CHAIN OF LIFE.
modern star coral, represented in Fig. 42, is an instance of the
latter condition. It shows nineteen or twenty animals, each
with a central mouth and fringe of short tentacles, aggregated
together, and two of them showing the spontaneous division by
which the number of animals in the mass is progressively
increased. The living coral shows only the soft animals and
the animal matter connecting them ; but if dead there would
be a white stony mass with a star-like cell or depression
cor'-esponding to each animal.
; ii their general plan, the oldest Corals were precisely of this
character, but they presented some differences in detail, which
have caused them to be divided into two groups, which are
eminently characteristic of the Palaeozoic age — the tabulate
' j"^..
:*La.i
Fig. 42. — Living Anthozoan Coral (Asireen).
or floored corals, and the rugose or wrinkled corals. In the
former (Fig. 43) the cells are usually small and thin-walled,
often hexagonal, like a honeycomb, and are floored across at
intervals with tabulae or horizontal plates. A few modern
corals present a similar arrangement,^ but this kind of structure
was far more prevalent in the Palaeozoic. In the second type
the animals are usually larger and often solitary, the cell has
strongly marked radiating plates, while the horizontal floors
are absent or subordinate, and there is usually a thick exter-
nal rind or outer coat (Figs. 44, 45). In general plan, these
^ Heliopora^ an Alcyonarian ; PocUhpora, an Anthozoan,
'ill
THE AGE OF INVERTEBRATES OF THE SEA. 59
rugose corals closely resemble those of our modern reefs ; but
they differ in their' details of structure, and only a very few
Fir. 43.— Tabulate Corals.
a, Halisites, and b, Favosites. Upper Silurian.
modern forms from the deep sea are regarded as actual modern
representatives.^ One curious point of difference is that their
Fig. 44.— Rugose Coral {Heliophyllum Halli). Devonian.
radiating laminae begin with four, and increase by multiples of
that number, while in modern corals the numbers are six and
multiples of six ; a change of mathematical relation not easily
accounted for, and which assimilates them to hydroids on the
1 Haplophyllia, Guynia, Duncania, of Pourtales.
6o
THE CHAIN OF LIFE.
one hand, and to a higher group, the Alcyonids, on the other,
both of which prefer four and eight to six, or have had these
numbers chosen for them. In the Mesozoic period the tabulate
and rugose corals were replaced by others, the porous and solid
siiiiM
■ '■' ■ynjir
Fig, 4t«. — Zaphrentis frolijica (Billings). Devonian.
corals of the modern seas ; but, in so far as we know, the
animals producing these, though differing in some details, were
neither more nor less elevated than their predecessors, and
they took up precisely the same role as reef builders in the sea,
Fig. 45. — Rugose Corals.
a. Za/Arenii's Mi'nas {Dn.), a.nd d, Cyathophyllum Billiiigsiijixi.). Carboniferous.
though with probably more tendency to the accumulation of
great masses of coral limestone in particular spots.
Leaving the corals, we may turn to the sea- stars and sea-
!?
THE AGE OF INVERTEBRATES OF THE SEA. 6i
urchins. These merely put in an appearance in the Early
Cambrian, but become vastly multiplied in the Silurian,
where the stalked feather stars (Crinoids) (Fig. 46), seem to
have covered great areas of sea-bottom, and multiplied so
rapidly that thick sheets of limestone are largely made up of
Fig. 46.— Modern Crinoid {Rhizocrinus Lqfotensis).—Mx.tx Sars.
the fragments of their skeletons. The ordinary star-fishes
appear first in the Silurian (Fig. 47). The sea-urchins begin
in the Upper Silurian, the early species having numerous and
loosely attached plates, like some of those now found in the
deep sea ' (Fig. 48).
* PaliTchinus.
62
THE CHAIN OF LIFE.
i[
The most curious history in this group is that of the feather-
stars. In the Early Cambrian they are represented by a few
species known to us only in fragments, and these belong to a
humble group (Cystideans) resembling the larval or immature
condition of the higher Crinoids. Fig. 49 shows one of these
animals of somewhat later age. They have few or rudimentary
arms and short stalks, and want the beautiful radial symmetry
of the typical star-fishes. In the Silurian these creatures are
reinforced by a vast number of beautiful and perfect feather-
stars (Figs. 50, 51). These continue to increase in number
and beauty, and apparently culminate in the Mesozoic, where
gigantic forms exist, some of them probably having more
Fio. 47. — Palo'aster Niagarensts
(Hall). One of the oldest star-fishes.
Fig. ^%.—Palffchinwt clliptic7ts (McC'y).
One of the oldest types of sea-urchins.
complicated skeletons, in so far as number of distinct parts is
concerned, than any other animals. Buckland has calculated
that in a crinoid similar to that in Fig. 52 there are no less
than 150,000 little bones, and 300,000 contractile bundles of
fibres to move them. In the modern seas the feather-stars
have somewhat dwindled both in numbers and complexity,
and are mostly confined to the depths of the ocean. On the
other hand, the various types of ordinary star-fishes and sea-
urchins have increased in number and importance. We thus
find in this group a certain advance and improvement from the
Cystideans of the Early Palaeozoic to the sea-urchins and their
allies. This advance is not, however, along one line, for the
THE AGE OF INVERTEBRATES OF THE SEA. 63
Cyslideans continue unimproved to the end. Tlie Crinoids
culminate in the Mesozoic, and are not known to give origin to
anything higher. The star-fishes and sea-urchins commer.v.3
independently, before the culmination of the Crinoids, and,
though greatly increased in number and variety, still adhere
very closely to their original types.
Fig. 49. — Plcurocys.iites
sqnamosns. L. Silunan.
After Billings.
Fig. 50. — HeterocrhiHS
simplex (Meek). One c\
the least complex crinoids
of that period. Lower
Silurian.
Fig. 51. — Body of Gly^it}-
crinus. Lower Silurian.
The great sub-kingdom of the Mollusca, including the bivalve
and univalve shell-fishes, makes its first appearance in the
Cambrian, where its earliest representatives belong to a group,
the Arm-bearers or Lamp-shells (Brachiopods), held by some to
be allied to worms as much as to mollusks. The oldest of all
these shells are allies of the modern Lifiguice (Fig. 54), some oi
64
THE CHAIN OF LIFE.
the earliest of which are shown in Fig. 55. The modern Sin-
gula is protected by a dcH'^ate two-valved shell, composed,
unlike that of most other mollusks, of phosphate of lime or
bone earth. It lives on sand-banks, attached by its long
flexible stalk, which it buries like a root in the bottom. Its
food consists of microscopic organisms, drifted to its mouth
by cilia placed on two arm-like processes, from which the group
derives its name. In the modern world about one hundred
Fig. 52. — Exiracrinus Briareus.
Reduced. Jurassic.
Fig. S3 —Pentacrinus caput-medusce.
Reduced. Modern.
species of Brachiopods are known, belonging to about twenty
genera, some of which differ considerably from the Lingulae.
The genus Terebratula^ represented at Fig. 5 5 a, is one of the
most common modern as well as fossil forms,' and has the
valves unequal, with a round opening in one of them for the
.stalk, which is attached to some hard object, and there is an
internal shelly loop for supporting the arms.
hi-
THE AGE OF INVERTEBRATES OF THE SEA. 65
These curious, and in the modern seas, exceptional shells, were
dominant in the Palaeozoic period. Upwarils of three thousand
fossil species arc known, of which a large proportion belong to the
Cambrian and Silurian, nine genera appearing in the Cambrian,
and no less than fifty-two in the Silurian. The history of these
creatures is very remarkable. The Lingulae, which are the first
to appear, continue unchanged and with the same phosphatic
shells to the present day. Morse, who has carefully studied
'■''''••''Wr-
..d
Fig. 54. — Ltngula anatina.
With flexible muscular
stalk. Modern.
Fig. 55. — Cambrian and Silurian Lingulae. n,
LiHgulella JWntihewi (Ha.ru). Acadian group.
d, LtHgula guadratn{yia\\). Lower Silurian.
c, Liujulella prima (Hall). Potsdam, d,
Linguiella antiqua (Hall). Potsdam.
an American species, remarks in illustration of this, that it is
exceedingly tenacious of life, bearing much change of depth,
temperature, etc., without being destroyed. The genus Discina^
which is nearly as old (Fig. 56), also continues throughout geo-
logical time. The genus Orthis (Fig. 57), which appears at the
same time with the last, becomes vastly abundant in Silurian
times, but dies out altogether before the end of the Palaeozoic
Rhynchonella (Fig. 58), which comes in a little later, near the
F
66
THE CHAIN OF LIFE.
l)eginning of the Siluro-Cambrian, continues to this day. Spirifcr
and Productus (Figs. 59 and 60) appear later, and die out at
Kk;. 55^». — Tereliratuta saccnlus
(Mariin). Carboniferous.
Fig. 56. - nischia Acndkn (Hartt). Lo >ver
Cainbru-ia of New liruiiswick.
the close of the Palaeozoic. So strange and inscrutable arc
the fortunes of these animals, which on the whole have lost in
Fig. 57. — Brachiopods; genus (?r//«i-.
a O Billinesi (Hartt). Lower Cambrian, b, O. pectinella (Hall). Lower Silurian.
,u V. muingsi yyxx^) ^^ ^ ^^^^^ (Eichwald). Lower Silurian.
the battle of life, so that their place in nature is vastly less
important than it was. it has been suggested that if any group
.^^l^
J\ : ML Ji t i/
wmBWBfl^
Fig i^.—Rhynchonelia tncreoresccns (Hall). Lower Silurian.
of c-eacures could thr-^w light upon the theory of descent with
modification, it would be these ; but Davidson, who has perhaps
THE AGE OF INVERTEBRATES OF THE SEA. 67
studied them more thoroughly than any other living naturalist,
finds them as silent on the subject as the sponges or the corals.
In a serifis of papers recently published in the Geological
Magazine^ ue remarks as follows :
" We find that the larger number of genera made their first
Fig. 59. — Spiri/ermucronatus (f2onn.i). Devonian.
appearance during the Palceozoic periods, and since they have
been decreasing in number to the present period. We wil
leave out of question the species, for they vary so little that it
is often very difficult to trace really good distinctive characters
between them ; it is different with the genera, as they are, or
Tig. 59^. — Athyris subtilita(\{6\\). Carboniferous.
u, •■ Exteriors, c, Interior, showing spirals.
should be, founded on much greater and more permanent dis-
tinctions. Thus, for example, the family Spiriferiim "nchules
genera w^ich are all charar^'^.rised by a calcified spiral lamina
for the support of the brachial appendages ; and , however varied
these may be, they always retain the distinctive characters of
the group from th r first appearance to their extinction. The
F 2
63 THE CHAIN OF LIFE.
Brachiopodist labours under the difficulties of not being able to
determine wiiat are the simplest, or which are the highest
families into which either oi the two great groups of his
favourite class is divided ; so far, then, he is unable to point out
any evidence favouring progressive development in it. ]iut,
confining himself to species, he sees often before him great
varietal changes, so much so as to make it difficult for him to
define the species; and it leads him to the belief that such
groups were not of independent origin, as was universally
thought before Darwin published his great work on the Origin
of Species. But in this respect the Brachiopoda reveal nothing
more than other groups of the organic kingdoms.
Tv. , (lu.—J'rodiictus cora {M'Orh'xgwy). Carboniferous.
•' Now, although certain genera, such Si^Terebratnla, Rhynchoti.
ellaj Crania, and Discina, have enjoyed a very considerable
geological existence, there are genera, such as Strimji^ocephalus,
Uncites, Porambonites, Koninckina, and several others, which
made their appearance very s'uddenly and without any warning ;
after a while they disappeared in a similar abrupt manner,
having enjoyed a comparatively short existence. They are all
possessed of such marked and distinctive internal characters
that we cannot trace between them and associated or synchron-
ous genera any evidence of their being eitlier modifications of
one or the other, or of being the result of descent with modifi-
cation, 'i'herefcre, although far from denying the possibility
or probwibility of the correctness of the Darwinian theory, f
THE AGE OF INVERTEBRATES OF THE SEA. r.g
could not conscientiously affirm that the Brachiopoda, as far as
J am at present ac(iuainted with them, would be of much ser-
vice in proving it. The subject is worthy of the continued
and sekious attention of every well informed man of science.
The sublime Creator of the universe has bestowed 6n him a
thinking mind ; therefore all that can be discovered is legitimate.
Science has this advantage, that it is continually on the advance,
],',f;. 6i.— Clrouj) of Older i':il;i; >zoic I,:iine!Iihranchs.— Aft«;r Hillitiys.
J Ciicullea npitiia. 2, Niinila ohlnn^a. 3, Nnoila liuratn. 4, Cypriinrdia trunaxta
5, Tellina ovata. 6, Niuula bellatula. 7, Modiola coiuciilrua.
and is ever ready to correct its errors when fresh light or new
discoveries make such necessary."
The ordinary bivalves, like the mussels and cockles, now so
very plentiful on our coasts, are rare in the Cambrian and Silu-
rian, and for the first time make a somewhat consjjicuous
appearance in the Upper Silurian and Devonian. liut from
the first they resemble very closely their modern successors,
though on the whole neither so large nor so ornate (Fig. 6i)
70
THE CHAIN OF LH-^E.
Tlieir fortunes have thus been precisely the oi)posite of those of
the lirachiopods, though in neither case is tlicre very marked
elevation or deterioration in the individual animals. A very
similar statement may be made as to the sea-snails, whether tlie
Ik;. Ci2. — Conitlnn'd /i/itii/tosiiitu (^\)n.). A Carboniferous Pteropod,
curious winged snails (Pteropods) or the ordinary crawlers (Gas-
tropods). The former come in early, and are represented by
I'alajozoic forms finer than any now extant. Tlie genus Conularia
(Fig. 62) presents some Silurian species six inches or more
Fir;. 63. — Silurian Sea-snails. Canada.
a, Murchisonia hicincta (Hall), b, ricurolottinria uiiihilhutiiln {}\\\\\). c, Miirchisniiia
i'r<(C/V/i' (Hall), d, Ih'ilcro/>/ion suicututm {^i'AW'in^'^).
in length, which arc giants in comparison with any now
living. The forms of more ordinarv (iastropods from the
Silurian represented in Fig. 63 will suffice* to show that their
styles are not very dissimilar from those still extant. As in
THE AGE OF LNVERTEHRATES OF Tlir: SEA. 7' '
the case of the ordinary bivalves, however, the modern (ias-
tropods much exceed in numbers and magnitude those of the
J'alceozoic.
The highest group of MoUusks, represented in the modern
ocean by the Nautili and Cuttle-fishes, has a history so strange
and eventful, and so different from what might have been
anticipated, that it perhaps deserves a more detailed notice,
more especially as Uarrande has recently directed marked
attention to it in his magnificent work on the Palaeontology
of Bohemia.
The Cuttle-fishes and Squids and their allies are, in the
modern seas, a most important group (Fig. 64). The great
numbers in which the smaller species appear on many coasts,
and the immense size and formidable character of others ;
their singular apparatus of arms, bearing suckers, their strange
forms, and the inky secretion with which they can darken the
water, have at all times attracted poi)ular attention. The
great comjjlexity of their structures, and the fact that in many
points they stand (juite at the head of the invertebrates of the
sea, and approach most nearly to the elevation of the true
fishes, liavc secured to them the attention of naturalists. Some
of these animals have shelly internal supports, and one genus,
that of the Argonauts, or Paper Nautili, has an external pro-
tective shell. Allied, though more distantly, to the cuttle-
fishes, are the true Nautili, represented in the modern sea
principally by the Pearly Nautilus, though there are two other
species, both of them very rare. The modern pearly nautilus
(Fig. 65) may be regarded as a peculiar kind of cuttle-fish
])rovided with a discoidal shell for protection, and also for
floatage. The shell is divided into a number of chambers
by partitions. Of these the animal inhabits the last and
largest. The others are empty, and are connected with the
body of the animal only by a ]npe, or siphuncle, with mem-
branous walls and filled with fluid. Thus provided, the
nautilus, when in the water, has pradi'ally no weight, and (an
• 72
THE CHAIN or LIFE.
move up or down in the sea with the greatest facihty, using
its sucker-bearing arms and horny beak to seize and devour
the animals on which it preys. The buoyancy of the shell
seems exactly adapted to the weight of the animal ; and this
proportion is kept up by the addition of new air-chambers as
the body increases in size. In the modern seas this singular
little group stands entirely isolated, and its individuals are
so rare that it is difficult to procure perfect specimens for
Vu:. 64.— Snuid (/,tf/4'w). Fi';. 65. -- Pearly Nautilii«fA/rt«///'<.9/(7w//7/«.v).
/I, Mantle. />, Its dorsal fold, c, Hood.
o, Kyc. /, 'i'enlacles. _/, Funnel. ^, Air
chaiiilK-rs. //, ^>ii>liunclc.
collections, though its mechanical structure and advantages
for the struggle for existence seem of the highest order. But
in the old world of past geological time the case was
altogether different.
'J'he Nautiloid shell- fishes burst suddenly upon us in the
beginning of the Siluro-Cambrian, or Lower Silurian, Barrande's
second fauna; and this applies to all the countries where
THE AGE OF INVERTEBRATES OF THE SEA, 73
they have been studied. In this formation alone about 450
species are known, and in the Silurian these increase to 1,200;
and here the group culminates. It returns in the Devonian to
about the same number with the Lower Silurian, diminishes
in the Carboniferous to 350, and in the Mesozoic, where
the Nautiloid forms are replaced by others of the type
"i 1
Kk;. (i-j.—Gomphoccras.
Vv;. fiCy — Orthocerns. I-owe» Silurian.
'I'he dotifd lin- shows the position
of the siphuncle.
Fi<;. 08. — Liluitcs.
of the Ammonites, becomes largely reduced. In the Tertiary
there are but nineteen species, and, as already stated, in
the modern world three. These statements do not, however, re-
present the whole truth. In the Paheozoir, in addition to the
genus Nautilus, we have a great number of other genera, some
with perfectly straight siielLs, like Ortlioceras (Fig. 66), others
74
THK CHAIN OF LIFE.
bent {Cyrtoccras)^ others differing in the style of siphuncle,
(jr aperture, or chambers {Endoceras^ Gomphocenu^ Liluiks,
l.^
O
\
(
\
\
\
\
I'k;. (jfj — Nautilus Aiioneinia (l»n.). Carh/iiifcrous.
a, Shell, reduced, b, Stctiun, showing siphuncle.
Figs. 67 to 69), or inflated into sac-like forms {Ascoceras). There
is, besides, the family of the GoniatidcE (Fig. 70), with the
SiysSC
I'JG. 70. — Gonialites cnn'ntria (Philips). Carboniferous.
chambers thrown into angular folds and the siphuncle at the
back. Further, some of the early forms, as the Orthoceratidte.
THE AGE OF INVERTEHRATES OF THE SEA. 75
attain to gigantic diinensions, beinjjj six feet or more in lengtli,
and nearly a foot in diameter. Thus the idea tiiat we should
naturally form from the study of the Nautilus, that it rejiresents
.1 type suited for much more varied and important ada[>tations
than those that we now see, is more than realised in those
Palaeozoic ages when these animals seem to have been the
lords of the seas.
When we leave the Palaeozoic and enter the Mesozoic, though
the Nauliloid shells still abound, we find them suj)erscded, in
great part, by a nobler form, that of the Annnonitidai (iMgs. 71,
Ya;. ■ji.—Ceratiles iiodosim (Sclilotli). Triussic.
72). These arc remarkable for the ornate markings on the
surfaces of their shells, and for the beautifully waved edges of
the partitions (Fig. 72<7), which, by giving a much more com-
plete support to the sides of the shell, must have contributed
greatly to the union of lightness and strength so important to the
utility of the shell as a float. This type admits of r" the same
variety of straight, bent, and curled forms with the simpler
Nautiloid type, and some of the species are of great size, Am-
monites being known three feet or more in diameter. These
animals, unknown in the Palaeozoic, appear in numerous species
76
THE CHAIN OF LIFE.
in the Early Mesozoic, culminate in hundreds of beautiful species
in the middle of that era, and disappear for ever at its close,
leaving no modern successors. Many and beautiful species of
Ammonites and their allies have been obtained from the
Fig. 72. — A//iHto»iUs yason{Reinecke). Jurassic.
Mesozoic rocks of British Columbia and other parts of the
west coast of North America, perfectly representing this group
as it occurs at the same period in Europe, and closely resembling
f^Vv
'v
Fig. 72a. — Suture ot Atnmomtes componens (Meek), ot British Columbia. Shoving
the complicated foldit.g of the edges of the chambers to give strength to the shell.
Cretaceous.
^a
the Mesozoic Ammonites of India. These animals have all
perished, yet the Atlantic and the Pacific roll between, apparently
with conditions as favourable for their comfortable existence as
those of any previous time. They perished long ago, at the
THE AGE OF INVERTEBRATES OF THE SEA. V
dawn of the Tertiary ; yet the genus Nautilus, one of the oldest
and least improved of the whole, survived, and still testifies to
the wonderful contrivance embodied in these animals.
These are merely general considerations, but Barrande, in his
Etudes Generales, goes much farther. He sums up all the known
facts in the most elaborate manner, considering first the em-
bryonic characters of the shell in the different genera, then their
Fig. 73. — Cretaceous Ammonltidae,
a, Baculites. b, Ancyloceras, c, Crioceras. d, Turrilites.
distribution in space and time, then all the different parts and
characters of the shells in the different groups — the whole with
reference to any possible derivation of the species ; and he
finds that all leads to the result that in every respect these
shells seem to have been so introduced as to make any theory
of evolution with respect to them altogether untenable. In his
concluding sentence this greatest of Palaeozoic palaeontologists
'/]
^
/,.
w-^
</
y
^
IMAGE EVALUATION
TEST TARGET (MT-3)
1.0
M 12.5
2.2
1.1
1.25
■yui.
1.4 mil 1.6
78
THE CHAIN OF LIFE.
affirms that, "The theoretical evohition of the Cephalopods
is, like that of the Trilobites, a mere figment of imagination^
without any foundation in fact."^
I have reserved no space to notice the geological history of
the other and higher group of Cephalopods, including the true
Cuttles and Squids. This is perhaps less to be regretted, as,
from the absence of external shells, they are likely to be much
Fig. 7^.—Belemnitc.— Ahtr Philips.
less perfectly known as fossils. So far as known, they are
vastly younger than the Nautiloids, for no examples whatever
have been found in the Palaeozoic. They appear abundantly in
Fig. 74/1. — Belemnoteuthis antiquus. Supposed to be a Belemnite, with soft parts
preserved. — Jurassic. — After Mantell.
the Mesozoic, but are there represented principally by an
extinct group of squids (Belemnites and their allies. Figs. 74,
74«), remarkable for the great and complicated development of
their internal support, which has a chambered float as well as a
solid sheath. This family becomes extinct at the close of the
^ ♦' Un produit de I'imagination, sans aucun fondement dans la realite."
THE AGE OF INVERTEBRATES OF THE SEA. 79
Mesozoic, though the cuttles as a whole perhaps culminate in
the modern.
The remarkable group of the Trilobites had precedence in
order of time of the Nautiloid shell-fishes. No animal structures
can well be more dissimilar than those of the two great groups
of aquatic animals which popular speech confounds under the
name of " shell-fishes." Take a whelk and a crab, for example,
and compare their general forms, ^he structure of their shells,
and their organs of motion, and it is scarcely possible to imagine
any two animals more unlike; and when we examine their
b
a, Paradox ides.
Fig. 75.— Cambrian Trilobites.
d, Dikellocephalus. c, Conocephalites (head), d, AgnosUts (head
and tail).
anatomy in detail this difference does not diminish. They have,
it is true, corresponding parts, and these parts serve similar
uses, but in plan of structure they are wholly different. Yet
both animals may live in the same pool, and may subsist on
nearly the same food. If we attempt to find some common
type which both resemble, we may trace the structure of the
crab back to those of some of the marine worms with which it
has some affinity, and those of the whelk to such creatures as
the Lingular which are supposed to have a resemblance to
8o
THE CHAIN OF LIFE.
the worms. But still the two types, that of the Mollusk and
the Articulate, are distinct even from their first appearance in
the egg, nor have either any close affinities with the Protozoa,
the Hydroids, or the Corals.
Both types meet us in the Early Cambrian, but while the
Mollusk is there represented only by low forms, the Articulate
is then not only in the humble guise of the worm, but in the
complex and highly organised form of the Trilobite (Figs. 28
and 75). What older phases they may have passed through we
Fig. 76.-Transverse section of Calymene. A Silurian Trilobite. -After Wolcott.
a Dorsal shell, b. Visceral cavity, c, Legs d, Epipodite-giU-cleaner or palp.
' e. Spiral gills.
know not ; but in the Lower Cambrian we have various forms
of these animals, including some of the largest known as well
as some of the smallest ; some of the most complex in num-
ber of parts as well as some of the simplest. These animals,
in short, seem to have appeared at once all over the world
fully formed, and in a variety of generic and specific forms ; and
nothing short of a very large faith in the imperfection of the
geological record can suffice to account for their evolution.
A Trilobite is a creature in whose structure the number three
THE AGE OF INVERTEBRATES OF THE SEA. Si
is dominant. Seen from above, it presents three divisions from
front to rear : — first, a cephalic shield or head-piece ; secondly*
a thorax, divided into several segments movable upon each
other ; and thirdly, a tail-piece or pygidium, which, when brought
against the head by the rolling up of the body segments, effec-
tually covers the lower parts. This lower portion was until
Fig. 76rt.— Burrows of Trilobite and of modern King crab. The Trilobite burrow is known
as Ruschimtes.
lately little known ; but the discoveries of Billings and of
Wolcott have enabled us to restore the jaws under the head,
the jointed legs and spiral gills under the thorax, and thus to
complete the structure of the animal, and understand better its
relations to modern crabs and shrimps (Fig. 76). Of these it
certainly comes nearest to the King-crabs and Horseshoe-crabs,
82
THE CHAIN OF LIFE.
a somewhat limited group at present, and one which reaches
back in geological time only to the Upper Silurian, when the
Trilobites had perhaps already passed their culmination.
Constructed as above described, the Trilobite could swim, as
is supposed, usually on its back or side. It could crawl on
the bottom. Using its snout as a shovel, it could burrow like a
modern King-crab (Fig. ySa) ; and when pressed by danger some
species could roll themselves into balls and defy their enemies.
Fig. 77. — Silurian Trilobites.
a, Isotebis. b, Homalonotiis. c, Calymenc.
This type of animal, entering on the stage in full force in
the Older Cambrian, continues under many forms through the
whole Palaeozoic age, dying out finally in the Carboniferous.
Figs. 77 and 78 show a few of the forms of the Silurian,
Devonian, and Carboniferous.
Contemporaneously with the dawn of the Trilobite group,
appear some small shrimp-like forms (Fig. 28),^ and others
with bivalve shells (Fig. 79), which are closely allied to modern
forms,'^ and, like the Lingulce, persist through the succeeding
^ Ilyirenocaris. ^ Phyllopods and Ostracods,
THE AGE OF INVERTEBRATES OF THE SEA. 83
formations with little more than specific change — presenting in
this a strange contrast to the Trilobites. While the latter were
Fig. 78. — Devonian and Carboniferous Trilobites.
a, Phaceps lat'frons (Bronn). b, Philipsia Howi (Billings) (tail).
still flourishing, about the close of the Lower Silurian, a
remarkable group of large and highly-developed creatures,
I 0.
Fig. 79. — Palaeozoic Ostracod Crustaceans. Magnified.
a. Bairdia. b. Cytherella itijlata (Jones), r, Cythere. Carboniferous, d. Beyrtchia
yonesit (Dn). Carboniferous, e, Beyric/tiupustulosa{iia.\\). Upper Silurian.
allied to the Trilobites, but suited for rapid swimming rather
than creeping, was introduced ; and in the Upper Silurian and
G 2
^h
84
THE CHAIN OF LIFE.
&»
Devonian these creatures ^ attained to gigantic sizes, exceeding
probably, any modern Crustaceans, and were tyrants of the
seas. Fterygotus anglicus {¥\g. 80) is supposed i-o have attained
the length of six feet. Yet these noble representatives of
the Crustaceans became extinct in the Carboniferous. On
the other hand, a few small king-crabs appear in the Upper
Silurian, and this type still continues, and seems to culminate
as to size in modern times j so diverse have been the fortunes
of these various groups.
The higher, or decapod Crustaceans, now familiar to us in
the modern crabs and lobsters, are first found in a few small
Fig. 80. — Fterygotus anglicus. Reduced. — After Page and Woodward.
species in the Carboniferous, but they are preceded in the
Devonian by at least one species of the allied group of the
Stomapods (Figs. 81, 82).
The Paheozoic age of geology is thus emphatically an age
of invertebrates of the sea. In this period they were dominant
in the waters, and until toward its close almost without rivals.
We shall find, however, that in the Upper Silurian, fishes made
their appearance, and in the Carboniferous amphibian reptiles,
and that, before the close of the Palaeozoic, vertebrate life in
^ Fterygotus^ Eurypterrts, etc.
THE AGE OF INVERTEBRATES OF THE SEA. 85
these forms bad become predominant. We shall also see that
just as the leading groups of Mollusks and Crustaceans seem
to have had no ancestors, so it is with the groups of
Vertebrates which take their places. It is also interesting to
observe that already in the Palaeozoic all the types of inverte-
brate marine life were as fully represented as at present, and
that this swarming marine life breaks upon us in successive
waves as we proceed upward from the Cambrian. Thus the
progress of life is not gradual, but intermittent, and consists in
the sudden and rapid influx of new forms destined to increase
'. ':■■: ... -i
^''^ ' I//
Fig. 81. — Amphif<eltis paradoxus (Salter).
A Devonian Svomapud.
Fir,. 82. — Anthropalcemon Hilliana
(Dn ). A Carhoniferuus Decapod.
The carapace only. .
and multiply in the place of those which are becoming effete
and ready to vanish away or to sink to a lower place. Farther,
since the great waves of aquatic life roll in with each great
subsidence of the land, a fact vvhich coincides with their
appearance in the limestones of the successive periods, it
follo'vs that it is not struggle for existence, but expansion under
favourable circumstances and the opening up of new fields of
migration that is favourable to ihe introduction of new species.
The testimony of palaeontology on this point, which I have
86 THE CHAIN OF LIFE.
elsewhere ad<luced at length,^ in my judgment altogether
subverts the prevalent theory of " survival of the fittest," and
shows that the struggle for existence, so far from being a cai^se
of development and improvement, has led only to decay and
extinction, whereas the advent of new and favourable condi-
tions, and the removal of severe competition, are the circum-
stances favourable to introduction of new and advanced
species. This testimony of the invertebrates of the sea we
shall find is confirmed by other groups of living beings, to be
noticed in the sequel.
Note.— Since writing the above chapter the author has received the
important memoir of Barrande on the Silurian Brachiopods, in which, as
tho result of the most elaborate and detailed comparisons, he concludes
that in the case of these shells, as in that of the Cephalopods and Tnlobites,
the introduction of species in geological time has not occurred by modifi-
cation, but must have depended on a creative process. It is such painstaking
researches as those of the great Bohemian palaeontologist which must finally
settle these questions, in so far as geology is concerned.
Professor Whitfield has announced [Am. yi. of Science, Jan. i»»o) the
discovery of remains of Decapod Crustaceans in the Devonian or Erian of
Ohio; thus carrying back this form of life one stage farther, and making
the highest Crustaceans still more distinctly contemporaneous w:th the
Trilobites.
^ Report on Devonian Fossil Plants of Canada, 187 1. Story of the
Earth and Man, 1873. Address to American Association, 1875.
)
I
CORDAITES, OF THE GROUP OF DoRY-CoRDAITES. Bk.VNCH RESTORED. —
After Grand' Eury.
CHAPTER IV.
THE ORIGIN OF PLANT LIFE ON THE LAND.
IF the graphite of the Laurentian rocks was derived from
vegetable matter, the further question arises, Was this vege-
tation of the land, or of the sea ? and something may be said on
both sides of this question. If there were land plants in the
Laurentian period, they must have grown either on rocks older
than the Laurentian itself, or on such portions of the beds of
the latter as had been raised out of the sea, forming perhaps
swampy flats of newly-made soil. But we know no rocks older
than the Laurentian, and there is no positive evidence that
any of the beds of that formation were other than marine.
Still it is not impossible that some of the beds which are now
graphitic gneisses may originally have been similar to the
bituminous shales, coals, or underclays of the coal formation.
The graphite occurring in veins, if of vegetable origin, must
have been derived from liquid bitumen oozing into fissures ;
and veins of this kind occur in later formations, both in marine
and freshwater beds. The only positive argument which has
been adduced in favour of the existence of abundant land
plants in the Laurentian is that of Dr. Sterry Hunt, derived
from the great beds of iron ore, which it is difficult to account
for chemically except on the hypothesis of the decay in the air
of great quantities of vegetable matter. The question must
remain in doubt till some one is fortunate enough to find
90 THE CHAIN OF LIFE.
portions of the Laurentian carbon retaining traces of organic
structure. My own observations, though somewhat numerous,
allow me only to say that the graphite sometimes presents
fibrous forms, that it occasionally appears as vermicular threads
— which, however, I suppose to be fillings of canals of Eozoon
— and that in the graphitic beds there are occasionally slender
root-like bodies of a lighter colour than the mass ; but none of
these indications are sufficient to determine anything as to its
vegetable origin, or the nature of the plants from which it may
have been derived.
In any case, the quantity of carbon which has been accumu-
lated in the Laurentian rocks is very great. I have measured
one bed at Buckingham, on the Ottawa, estimated to contain
20 per cent, of carbon, and which is at least eight feet in
thickness. Sir William Logan has described another similar
bed from ten to twelve feet thick, and more recent reports of
the Geological Survey of Canada mention a bed supposed to
be twenty-five feet thick, in which Mr. Hoffman finds 30
per cent, of carbon. On the whole the quantity of carbon in
the graphitic zone of the Laurentian is comparable with that
in certain productive coal-fields, and we certainly have in the
subsequent geological history no examples of such accumu-
lations except from remains of the luxuriant vegetatipn of
swampy flats.
The Upper Laurentian and Huronian have as yet afforded
no evidence of land vegetation. The Cambrian, as already
stated, abounds in remains of sea-weeds ; but though the forms
which have been named Eophyton have been regarded as land
plants, this claim is, to say the least, very doubtful ; and I have
as yet seen nothing of this kind which did not appear to me to
be merely markings made by objects drifted over the bottom
or remains of marine plants. Yet in the Upper Cambrian there
are wide surfaces of littoral sandstone often containing minute
carbonised fragments, and which might be expected to afford
indications of land vegetation, had such existed. I have myself
THE ORIGIN OF PLANT LIFE ON THE LAND. 91
devoted many days of fruitless labour to the examination of the
large areas of Potsdam sandstone exposed in some parts of
Canada. But as these rocks \, .re evidently formed along the
borders of a Laurentian continent capable of supporting
vegetation, we may still hope for some discovery of this kind,
Fig. Zi.—Protannularia //arinessit (Nicholson). A Lower Silurian Plant, from the
Skiddaw series.
more especially if we could find the point where some fresh-
water stream ran into the Cambrian sea.
The oldest plants, probably higher than Algae, known to me
by their external forms, are those described by Nicholson 1 from
the Lower Silurian Skiddaw slates of the north of England
^ Geological Magazine, November, 1869.
92
THE CHAIN OF LIFE.
(Fig. 83). Their discoverer has named them Buthotrephis Hark-
nessii and B. radiata^ stating, liowever, that these two species
are not improbably portions of the same plant, and that its
form is rather that of a land plant than of an Alga. The
specimens of these plants which I have seen appear to me to
support the conclusion that they represent one species, and
this allied to the Aniiularicp. of the Devonian and Carboniferous
periods, which probably grew in shallow water with only their
upper parts in the air, and bore whorls or verticels of narrow
rr
Fig. 84.— American Lower Silurian Plants. — After Lefquereux.
a, Sphenophyllum printcBvum. b, Protostigtna sis^illarioides.
leaves. They were distant relatives of the Mare's-tails, or
Equisetums, of cur modern swamps and ponds.
Somewhat higher up in the Lower Silurian, in the Cincin-
nati group of America, Lesquereux finds objects which he
^ The genus Bnthot>eph''s includes f:upposed branching sea-weeds of the
Silurian. For this reason I would propose the name Frotannularia for
these plants.
THE ORIGLN OF PLANT LIFE ON THE LAND. 93
refers to the genus SphenophyUum, which is closely allied to
Annularia (Fig. 84, «), and also a plant wnich he terms
Protostigma (Fig. 84, b), and believes to be the stem of a
tree allied to the club-mosses.^ He also finds minute branch-
ing stems, which he refers to the genus Psilophytou^ to be
mentioned in the sequel ; but as to these I have some doubts
whether they may not be Zoophytes, allied to the Graptolites,
rather than plants of that genus. Almost simultaneously with
these discoveries, Saporta has announced the existence of a
fern (Eopteris) in Silurian slates of about the same age in the
Fig. Z^.—Eopteris MoHerei (Saporta). A Lower Silurian Fern, from France.
South of France (Fig. 85). • This leaf presents some remarkable
irregularities in the forms of its pinnae, which suggest doubts as
to its real nature ; but if a fern, its nearest allies are certain
large and peculiar ferns of the Middle Devonian, which I have
named Megalopteris. These discoveries tend to show the
existence in the Lower Silurian of plants representing all the
three leading families of the higher cryptogams 01; flowerless
plants, namely, the Club-mosses, the Mare's-tails, and the Ferns.
^ Lycopodiacece.
94
THE CHAIN OF LIFE.
Thus land vegetation begins with the highest members of
the lower of the two great series into which botanists divide
the vegetable kingdom.
If we now turn to the Upper Silurian, further evidence ot
land vegetation presents itself. Near the base of this great
series, the club-moss family is represented by a plant discovered
by Claypole in the Clinton group, and referred to a new genus
{Glyptodendron, Fig. 86). Plants of this family have also
been noticed by Barrande in Bohemia, and by Page in Scotland.
Their spore-cases have been recognised by Hooker in the
Ludlow of England ; and a humble but interesting member of
this family, connecting it with the pillworts, Psilophytoti
Fig. 86. —Fragment of outer surface oiGlyptodendron of Claypole. An Upper
Silurian '1 ree.
(Fig. 87), though more characteristic of the Devonian, has
been found in the Upper Silurian both in Canada and
the United States, No Ferns or Equiseta have as yet been
found in the Upper Silurian ; but in 1870 I recognised in some
fragments of wood from the Ludlow bone-bed, in the Museum
of the Geological Survey of Great Britain, the structure of that
curious prototype of the Pine tribe, to which I have given the
name Frotofaxites, and which was first recognised in the
Devonian of Gaspd
It is probable that these discoveries represent merely a small
proportion of the plants actually existing in the Upper
Silurian period. All the deposits of this age at present known
THE ORIGIN OF PLANT LIFE ON THE LAND. 95
to us are marine ; and most of them were probably formed at
a distance from land, so that it is little likely that land plants
Fig. ^i.-PdlopJtyionprinceps {T)x,.). Upper Silurian and Devonian. Restored
96 THE CHAIN OF LIFE.
could find theii way into them. At any time the discovery of
an estuarire or lacustrine deposit of Silurian age might wonder-
fully extend our knowledge of this ancient flora.
The Devonian or Erian age, that of the clas^^lc Old R^^d
Sandstone of Scotland, is that in wh ch we find the first great
and complete land flora ; and though this is inferior in number
of species to that of the succeeding Carboniferous, and greatly
less important with reference to its practical bearing on our
welfare, it is in some respects superior in that variety which
depends on diversity of soil and of station. To appreciate
this, it will be necessary to glance at the range and subdivisions
of the modern flora.
• In the modern world we divide all vegetation into two great
series, that of the Flowering Plants {F/icenogatns), which also
produce true fruits and seeds, and that of the Flowerless
Plants {Cryptogams)^ which produce minute spores instead of
seeds. The latter is in every respect the lower group. This
lower series is again divisible into three classes — first and
lowest, that of the Seaweeds, Moulds, and Lichens (Thall-
ophytes). Secondly, that of the Mosses and their allies
(Anophytes). Thirdly, that of the Ferns, Equisetums and
Club-mosses (Acrogens). In like manner the second, or
higher series is divisible into three classes : that of the Pines
and Cycads (Gymnosperms), having naked seeds not covered
by true fruits, and woody tissue of simple structure ; that of
the Palms and Grasses and their allies (Endogens) ; and last
and highest, that of the ordinary timber trees and other plants
allied to them, with exogenous stems, netted-veined leaves, and
a two-leaved embryo (Exogens). These last are in every
respect the dominant plants on our present continents.
Carrying with us this twofold division of the vegetable
kingdom and its subdivisions, we shall be prepared to under-
stand the relation of the more ancient floras to that now
living.
In the Devonian age we meet with no land plants of the two
THE ORIGIN OF PLANT LIFE ON THE LAND. 97
lower classes of the Cryptogams, and with scarcely any that can
be referred to the two higher classes of Phaenogarns, so that
the vegetation of this period presents a remarkable character
of mediocrity, being composed almost entirely of the highest
class of the flowerless plants and the lowest class of those that
fiower. Of the former there are Tr-e-ferns and vast numbers of
herbaceous forms (Figs. 88, 89), great Lycopodiaceous plants,
Fig. 88.— Trunk of a Devonian Tree-fern {Caulopteris Lockwoodi, Dn ). Gilboa
New Vork. One-third natural size.
immensely better developed than those now existing (Fig. 90),
and gigantic Calamites, allied to the Marcs'-tails (Fig. 91)!
along with humbler members of the same group (Fig. 95). Of
the latter there were Pines of great stature, known to us at
present only by their wood (Fig. 92) ; and that other allied
trees existed we have evi jnce in numerous seeds which
must have belonged to this class (Fig. 93), and in long flag-
u
98
THE CHAIN OF LTFE.
like leaves^ which modern discoveries would refer to th » same
group. As yet we know no Devonian Palms or Grasses ; and
Fig. 89. — Frond of Archceopteris J acksonH^w.). Devonian, of Maine.
only a single specimen has been found indicating the existence
Fig. 90.— Portion of a branch of Leptophleuvi rhombicutn (Dn.). A Lycopodiaceous
tree of the Devonian of Maine. Natural size.
of a plant of the highest vegetable class, that of the true
^ Cordaites.
THE ORIGIN OF PLANT LIFE ON THE LAND.
99
exogens. This unique specimen, found by Hall in the
Devoniin of the shores of Lake Erie, is a fragment of
mineralised wood, the structures of which are represented in
Fig. 94. The large ducts seen in cross section in Nos. i, 2,
Fig. ^T.—Calamiies radiaius (Brongniart). Middle Devonian of N. Brunswick.
and 3, and in longitudinal section in Nos. 4 and 5, and the
medullary rays, seen in Nos. i, 4, and 6, testify to the fact that
this chip of wood must have belonged to a tree of the same
type which contains our oaks, maples, and poplars; a type
a 2
lOO
THE CHAIN OF LIFE.
which does not appear to have become dominant till near the
close of the Mesozoic, but which already existed, though
rl
pi
<f3
[^■■ij^ '
AA^^V^
-.v-SW
^^W^-^-^:^
^
M^^
I)
Fig. 92.— a Devonian Taxine ConVer {Dadoxylon ounngondianum, Dn.)- St. John^
New Brunswick.
A, Fragment showing Stembergia pith and wood ; a, Medullary sheath ; b, Pith ;
c. Wood ; d. Section of pith.
B, Wood cell a, and hexagonal areiile and pore b. ,,,,.„
c Longitudinal secti. n of wood, showing n, Aredation, and b. Medullary rays,
u', Transverse section showing a. Wood-cells, and b. Limit of layer of growth.
perhaps only in few species, and only in upland and inland
positions, as far back as the Middle Devonian.
The Devonian flora seems to have been introduced in the
THE ORIGIN OF PLANT LIFE ON THE LAND. loi
northern parts of the American continent at a time of warm
and equable climate, and of elevation of new land out of
the Silurian sea. It spread itself to the southward, and was
finally destroyed in the great subsidences and disturbances
Fig. 93.- Group of Devonian Fruits, etc. Middle Devonian, New Brunswick.
A, CardincarpHin conintnvt.
b. Cardiocarpian acutuiit.
C, CnrdiocarpHUi Crampii.
D, C'lrdiocarpitni Bailcyi.
E, Trif;onocarpum racemosnm.
e', E-, Fruits enlarged.
F, Antholttkcs Dcvotiicus.
f', Fruit of the same.
c;, Annularia ncutninnfa.
H, Asterophyllites acicularis. h'. Leaf.
K, Cardiociirpum. (? young of a.)
L, Pinmilarin dispalans.
From Acadian Geology.
which closed the Devonian age, and which were probably
accompanied with refrigeration of climate. It was succeeded
by the more massive and richer, but more monotonous flora
of the Carboniferous, a period in which large areas of our
103
THE CHAIN OF LIFE.
continents were in the st ♦^e of swampy and often submerged
flats, and in wliich the climate was again warm and uniform.
The Carboniferous age was, even more emphatically than the
Devonian, an age of Acrogens and Conifers. A few Carboni-
ferous Fungi have recently been discovered, but there are no
KiG. 94.- Structures of the oldest-known Angiospermous Exogen (Syringoxylott
mirabilc, Dn.J. From Jiighteen-mile Creek, Lake Erie,
I. Transverse section X 100. 2 and 3. Portions of the same X 300. 4. Longitudinal
section X 300. 5. Fragment of duct from the same X 600. 6. Wood cells and
medullary ray X 600.
known Lichens or Mosses. There see m to be a few Endogens,
but no true Exogens. The great bulk of the plants consists of
Acrogens and Gymnosperms, as in the previous period. As
this flora is so very important and so much better known than
any other of those belonging to the infancy of the vegetable
THE ORIGIN OF PLANT LII-^E ON THE LAND. 103
kingdom, we may notice a little in detail some of its leading
forms.
Beginning with the Mares'-tails, we find these represented in
the Carboniferous by many gigantic species, attaining to almost
tree-like dimensions (Fig. 96). These aie the Calamites, which
formed dense brakes and jungles on the margins of the great
swampy flats of this period. Their tall stems, ribbed and
r*^
Fig. 95. — Astetophytliies pnrvula (Dn.), and Sf>henophyUnm antiquum (Dn),
Middle Devonian, New UruiiswicV.
jointed, bore whorls of leaves or branchlets. Sending out
horizontal root-stocks and budding out from the base, they
grew in great clumps, and had the capacity to resist the effects
of accumulating sediment by constantly sending out new stems
at higher and higher levels. The larger species assumed a
complexity in the structure of their stems unknown in their
modern congeners, and enabling them to grow to a great
^^^Vf fWW/j(
Fig. q6. — Calami tes. Carboniferous.
A, C. Siickovii. B, C. Cistiiifit.). c, Base of Calamites. d, e, Stmctures.
From Acadian Geology.
THE ORIGIN OF PLANT LIFE ON THE LAND. 105
height; 1 but their foliage and fructification were not correspond-
ingly advanced. Thus the family of the Equisetacese culminated
in the Carboniferous, and thenceforth descended gradually in
the succeeding ages, leaving the comparatively humble Mares'-
tails and Scouring Rushes as its present representatives.
The Ferns of the Carboniferous, hke those of the Devonian,
Fig. 97.— Carboniferous Ferns.
A, Odontopteris subcuncata (Bunbury). b, Neuro/>teris cordata (Brongniart).
C, Alethopterii ionchitica (Brongniart),
presented both gigantic forms like those of the tree-ferns of
the modern tropics, and delicate herbaceous pecies, and these
in g'-eat profusion. On the whole, they do not strike the
observer as very dissimilar from those of modern times. A
more critical examination, however, shows that the bulk of the
tree-ferns of the Devonian and Carboniferous are allied not to
1 Calamodendron and Aithropitys are forms of this kind.
lo6 THE CHAIN OF LIFE.
the Polypod type, which is the most common at present, but
to certain comparatively rare southern ferns, the Marattias and
their allies, characterised by a peculiar style of fructifica-
tion, pei iiaps adapting them to a moist and warm atmosphere
(Fig. 97).i Thus the ferns, while a wonderfully persistent type,
were in their grander forms far more widely distributed in the
Carboniferous than at present ; and genera now comparatively
rare, and limited to warm and moist climates, were then abun-
dant, and ranged over those temperate and boreal regions of
the Northern Hemisphere where only a few humble and hardy
species can now subsist. There were also some remarkable
and anomalous tree-ferns, of which that represented in Fig. 98
is an example.
The family of the Club-mosses, already, even in :he Devonian,
in advance of its modern development, exper js in the Car-
boniferous a remarkable and portentous extension into great
trees of several genera and many species, constituting apparently
extensive forests, and having the woody tissues of their stems
developed to a degree unheard of in their present representatives
(Fig. 99). Further, they become closely linked, in external form
at least, with another and more advanced type, that of the
Sigillarice. These remarkable trees were the most abundant
of all in the swamps of the coal-formation, and probably those
which most contributed to the accumulation of coal. They
presented tall pillar-like trunks, often ribbed longitudinally, and
with perpendicular rows of scars of fallen leaves. Dividing at
top into a few thick branches, they were covered with long
rigid grass-like foliage. Their fiuit was borne in rings or
whorls of spikes surrounding the branches at intervals (Fig.
160). Their roots were strangely symmetri-^al, spreading out
like underground branches into the soft soil by a regular pro-
cess of bifurcation, and were covered with rootlets diverging
in every direction, and so jointed to the main root that when
* Grand' Fury and Williamson have directed attention to this in the case
of those of France and England. _
THE ORIGIN OF PLANT LIFE ON THE LAND. 107
broken off they left round marks regularly arranged. These
roots are the so-called Stigmarm, so abundant in every coal-field,
and especially filling the " under-clays " of the coal-beds, which
are the soils on which the plants forming these beds were sup-
ported. The true botanical position of the Sigillarice has been
Fig. 98.— Carboniferous Tree-ferns.
A, Me^aJ>hyton vtagHificum {Dn.'). c, Palaapterd Hartii (Jin.).
D, F, Acadica (Dn.).
a matter of much controversy. Some of them undoubtedly
have structures akin to those of t' 2 tree-like Club-Mosses, as
Williamson has well shown, and may have been cryptogamous.
Others have structures of higher character, akin to thos . of the
modern Cycads, and seem to have borne nutlets allied to
those of these plants. Yet the external forms of these diverse
io8
THE CHAIN OF LIFE.
Fig. 99. — Lepidodendron corrugaUon (Dn.). A characteristic Lycopod of the Lower
Carbuniferous of America.
A, Restoration, b, Leaf, natural size, c, Cone. d, Leafy branch, e, Forms of
leaf-bases. F, Sporangium. I, L, M, N, o, Markings on stem and branches, in
various states.
THE ORIGIN OF PLANT LIFE ON THE. LAND. 109
Fig. 100,— Sigillariee of the Carboniferous.
A, Sigillaria Broivnii (Dn.). b, 5". rles^ant (Brongniart). b', etc. leaf and
Leaf-scars.
no THE CHAIN OF LIFE.
sorts are so similar that no definite separation of them has
yet been made. Either these anomalous trees constitute a
link connecting the two great series of the vegetable kingdom,
or we have been confounding two distinct groups, owing to
imperfect information.
Another curious, and till recently little understood, group
of Carboniferous trees is that known as Cordaitesj which
existed already in some of its species in the Devonian. Their
leaves are long, and often broad as well, and with numerous
delicate parallel veins, resembling in this the leaves of grasses.
Corda long ago showed that one species at least has a stem
allied to the Club-mosses. More recently Grand' Eury has
found in the South of France admirably preserved specimens,
which show that others more resembled in their structure the
Pines and Yews, and were probably Gymnosperms, approaching
to the Pines, but with very peculiar and exceptional foliage, of
which the only modern examples are the broad-leaved Pines of
the genus Dammara (Frontispiece to Chapter). Here again
we have either two very distinct groups, combined through
our ignorance, or a connecting link between the Lycopods and
the Pines.
The Yews and their allies among modern trees, while mem-
bers of the great Cone-bearing order, bear nut-like seeds in
fleshy envelopes, sometimes, as in the Ginkgo of Japan, consti-
tuting edible fruits. Seeds of this type seem to have been
extremely abundant in the Carboniferous age in all parts of
the world, and were probably produced by trees of several
genera {Dadoxylon^ Sigillaria, Cordaites, etc.) (Fig. loo).
Charles Brongniart has recently described no less than seven-
teen genera of these seeds from the coal-field of St. Etienne
alone, and it would be a low estimate to say that we probably
know as many as sixty or seventy species in all, while the
trunks of great coniferous trees allied to Taxineae, and
showing well-preserved structure, are by no means uncommon
in the Devonian and Carboniferous. Had these great Yews
THE ORIGIN OF PLANT LIFE ON THE LAND, iii
appeared for the first time in the Coal-formation, we might have
supposed :hat they had been developed from such Lycopods
as Lepidodendra, and that the Cordaites are the intermediate
forms ; but unfortunately the Pines go almost as far back in
geological time as the Lycopods, and it does not help us, when
in search of evidence of evolution, to finrl the link which is
iV
Fig. tox. — Trigonocarpum Hookeri {Dn^. A Gymnospermous seed.
a, Testa, b, Tegmen. c. Nucleus, d, Embryo.
missing or imperfect in the Early Devonian supplied in the
Coal-formation, where, for ihis purpose at least, it is no longer
needed.
We have said something of what was in the Palaeozoic flora ;
but what of that which was not ? We may answer : — Nearly
all that is characteristic of our modern forests, whether in the
ordinary Exogens which predominate so greatly in the trees and
112 THE CHAIN OF LIFE.
shrubs of temperate climates, or in the Palms and their allies,
which figure so conspicuously within the tropics. The few rare,
and to some extent doubtful, representatives of these types
scarcely deserve to be noted as exceptions. Had a botanist
searched the Palaeozoic forests for precursors of the future, he
would probably have found only a few rare species, while he
would have seen all around him the giant forms and peculiar
and monotonous foliage of tribes now degraded in magnitude
and structure, and of small account in the system of nature.
It must not be supposed that the Palaeozoic flora remained in
undisturbed possession of the continents during the whole of
that long period. In the successive subsidences of the conti-
nental plateaux, in which the marine limestones were de-
posited, it was to a great extent swept away, or was restricted
to limited insular areas, and these more especially in the far
north, so that on re-elevaticn of the land it was always peopled
with northern plants. Thus there were alternate restrictions
and expansions of vegetation, and the latter were always
signalised by the introduction of new species, for here, as
elsewhere, it was not struggle, but opportunity, that favoured
improvement.
In the Lower Silurian such lants as existed must have ex-
perienced great restriction at the age of the Niagara or Wen-
lock limestone. Those of the Upper Silurian suffered a similar
reverse at the time of the Lower Hederberg or Ludlow lime-
stones. This recurred at the close of the Devonian and in
the time of the Lower Carboniferous limestone ; and finally the
Palaeozoic flora disappeared altogether in the Permian, to be
replaced by new types in the Mesozoic, While, therefore, there
is a great general similarity in the successive Palaeozoic floras,
there are minor differences, so that the Devonian plants are for
the most part distinct specifically from those of the Lower Car-
boniferous, those of the Lower Carboniferous from those of
the Coal-formation, and those of the latter from those of the
Permian.
THE ORIGIN OF PLANT LIFE ON THE LAND. 113
With all these vicissitudes it is to be observed that there is
no apparent elevation of type in all the long ages from the
Devonian to the Permian, that the Acrogens and Gymnosperms
of these periods are in some respects superior, in all respects
KH{ua\, to their modern successors, and that their history shows
a decadence toward the modern period; that intermediate
forms arrive too late to form connecting links in time, that
several distinct types appear together at the beginning, and
that all utterly and apparently simultaneously perish at the end
of the Palaeozoic, to make way for the entirely- new vegetation
of the succeeding age. Theories of evolution receive no
support from facts like these, though their practical signifi-
cant, as parts of the one great uniform scheme of nature, is
sufficiently manifest.
Of what use then were these old floras ? To the naturalist,
vegetable life, with regard to its modern uses, is the great
accumulator of pabulum for the sustenance of the higher
forms of vital energy manifested in the animal. In the Palae-
ozoic this consideration sinks in importance. In the Coal
])eriod we know few land animals, and these not vegetable
feeders, with the exception of some insects, millepedes, and
snails. But the Carboniferous forests did not live in vain, if
their only use was to store up the light and heat of those old
summers in the form of coal, and to remove the excess of
carbonic acid from the atmosphere. In the Devonian period
even these utilities fail, for coal does not seem to have been
accumulated to any great extent, and the petroleum of the
Devonian appears to have been produced from marine vege-
tation. Even with reference to theories of evolution, there seems
no necessity for the long continuance and frequent changes of
species of acrogenous plants without any perceptible elevation.
We may have much yet to learn of the life of the Devonian ;
but for the present the great plan of vegetable nature goes
beyond our measures of utility; and there remains only what
is perhaps the most wonderful and suggestive correlation of
114
THE CHAIN OF LIFE.
all, namely, that our minds, made in the image of the Creator,
are able to trace in these perished organisms structures
similar to those of modern plants, and thus to reproduce in
imagination the forms and habits of growth of living things
which so long preceded us on the earth. We may indeed
proceed a step further, and hold that, independently of human
appreciation, these primitive plants commended themselves to
the approval of their Maker, and perhaps of higher intelli-
gences unknown to us ; and that in the last resort it was ibr
His pleasure that they were created.
I 2
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CHAPTER V.
THE APPEARANCE OF VERTEHRATE ANIMALS.
CONFESSEDLY the highest style of animal is that which
possesses a skull and backbone, with brain and nerve
system to match, and which embodies the general plan of
structure employed in man himself. Yet among the fishes,
which constitute the lowest manifestation of this type, are
some so rudimentary that the brain is scarcely developed, and
the skeleton is merely a cord of gristle. These are represented
in the modern world only by the Lancelot,^ a creature which
has sometimes been mistaken for a worm, and by a slightly
more advanced type, that of the Lampreys.^ In these
animals the Vertebrates make the nearest approach to the
lower domains of the animal kingdom, collectively known as
Invertebrates. We should naturally expect that since the
vertebrates succeed the inferior animals in time, their lower
types should appear first, and that these should be aquatic
rather than terrestrial. On the other hand, as the oldest fishes
that are certainly known are strongly protected with bony
armour, and had to contend against formidable Crustaceans and
Cuttles, we might suppose that the Lancelot and the Lampreys
are rather degraded types belonging to the modern period, than
the tme precursors of the other fishes.
^ Amphioxus. " Petromyzon, etc.
Ii8
THE CHAIN OF LIFE.
But if fishes like the Lancelot preceded all others, we may
never find in a fossil state any traces of their soft and perish-
able bodies ; and even the Lampreys have no hard parts except
small horny teeth, which might easily escape observation. But
palaeontologists have sharp ^yes, and it has not escaped them
that certain microscopic tooth-like bodies are somewhat widely
distributed in the older rocks. In Russia, Pander has found in
the Upper Cambrian and Lower Silurian, and also in the
Devonian and Carboniferous, minute conical and comb-like
Fig. I02. — Lower Silurian Conodonts. Magnified.— After Pander.
teeth, to which he has given the name of Conodonts (Fig. 102),
and which he supposes to be the teeth of ancient Lampreys.
Similar teeth have been found by Moore and others in the Car-
boniferous of England, and by Newberry in Carboniferous shales
in Ohio. In point of form, these bodies certainly resemble
the teeth of the humble fishes to which they have been referred.
In the case of the C^larboniferous specimens from Ohio — the only
ones I have had an opportunity to examine— the material is
APPEARANCE OF VERTEBRATE ANIMALS. 119
calcium phosphate, and the structures are more like those of
teeth of Sharks than of Lampreys, so that there can be no doubt
that they are really teeth of fishes, and probably of fishes of
somewhat higher grade than the Lampreys. The Cambrian
and Silurian specimens are said to be composed of calcium
carbonate, which would render it more probable that, as has
been suggested by Prof. Owen, they may have been teeth of some
species of Sea-snail destitute of shell. It is, however, possible
that they may have originally been horny, and that the animal
matter has been replaced by ca bonate of lime. The structures
which Pander has figured are certainly very like those of true
fish teeth, and would give some countenance to this last
supposition.^
Fig. 103 — Lower Carboniferous Conodont. Magnified.— After Newberry.
If these curious objects were really teeth of fishes, they carry
the introduction of these nearly as far back as that of the
MoUusks and Crustaceans. If they were not, then the earliest
known representatives of this class belong to a much later age,
that of the Upper Silurian. Here we have undoubted remains
of fishes belonging to two of the higher orders of the class ;
and in the succeeding Devonian these became multiplied and
extended exceedingly.
^ Dr. Newberry has kindly furnished me with specimens, and Dr. Har-
rington has submitted to analysis portions of shale filled with these little
teeth, the result giving 2*58 of calcium phosphate for the whole, which
indicates that the Conodonts are really bone. Their microscopic structure
approaches to that of tbe dentine of such Carboniferous fishes as Diplodus.
Hinde has described Conodonts from the Lower ijilurian of Canada, since
the above was wiitten.
I20
THE CHAIN OF LIFE.
Besides the inferior tribes alread}' referred to, the modern
seas and rivers present four leading types of fishes : — first, the
ordinary bony fishes (Teleostians), such as the Cod, Salmon,
and Herring ; secondly, the Ganoid fishes, protected with bony
plates on the skin, as the Bony-pike^ and Sturgeon ; thirdly, the
Sharks and their allies, the Dog-fishes and Rays ; fourthly, the
peculiar and at present rare group of semi-reptilian fishes to
which the name of Dipnoi has been given, on account of their
capacity for breathing both in air and in water.
Of these four types the first is altogether modern and
includes the great majority of our present fishes. It does not
make its appearance till the Cretaceous age, and then is at
once represented by at least three of the modern families, those
of the Salmon, Herring, and Perch. The history of the other
three groups is precisely the opposite of this. They abound
exceedingly at an early period, and dwindle to a much smaller
number in the modern time. This is especially the case with
the Ganoids and the Dipnoi. It is also remarkable that thest
groups of old-fashioned fishes^ are in some respects the highest
members of the class, approaching the nearest to the reptiles ;
but this accords with a well-known palaeontological law, namely,
that the higher members of low groups give way on the intro-
duction of more elevated types, while the lower members may
continue. Thus the decadence of these higher fish begins with
the incoming of the reptiles, just as the decadence of the higher
Mollusks and predaceous Crustaceans began with the incoming
of the fishes. Further, the modern Ganoids and Dipnoi are
mostly fresh-water animals, though the Sharks are largely pelagic.
In the Palaeozoic there seem to have been abundance ot
marine species of all these types ; but though marine, they
probably flourished most in bays and estuaries and on shallow
banks ; and the existence of these implies continental masses of
land. This explains the curious coincidence that the intro-
duction of fishes and of an abundant land flora synchronise,
* Lepidosteus. ^ Palccichthyes of Giinther.
APPEARANCE OF VERTEBRATE ANIMALS. 121
and that the ocean was still dominated by Invertebrates long
after the fishes had become supreme in bays, estuaries, and
rivers.
The first fishes that we certainly know are the Ganoids and
Sliarks, which appear near the close of the Upper Silurian, in
the English Ludlow for example (Fig 104). The Ganoids found
here all belong to an extinct group, characterised by the covering
of the head and anterior part of the body with large bony
plates. They are mostl> small fishes, and probably fed at the
bottom, and used their long or rounded bony snouts for
l''\c,. 1014. — a, Head-shield of an Upper Silurian fis,h {Cyat/ias^/s). b. Spine of a Silurian
Shark (Onchtis icntti-striatus, Agass.). c, Scales of Thclodns.
grubbing in the mud for food. In this respect they present
a singular resemblance to the Trilobites, so that wc seem to
have here animals of an entirely new type, the Vertebrate, and
with bony instead of shelly coverings, taking up the role and,
to some extent, the external form of a group about to pass away.
Yet I presume that no derivationist would be hardy enough to
affirm that the Trilobites could have been the ancestors of
these fishes. Nor indeed is any ancestry even hypothetically
known for them, for even the doubtful Lampreys of the Lower
Silurian are too remote in structure to be used in that way.
122 THE CHAIN OF LIFE.
The head-shield copied in outline in Fig. 104, and the restora-
tion after Lankester in the frontispiece to this chapter, may
serve to represent these curious primitive Ganoids, which are
continued in the Devonian fishes represented in Figs. 105, 106.
Along with these, and not improbably their enemies, were
certain Sharks (Fig. 104), known to us only by the spines which
Fig. xo^.—Cephalasph Z?a«/Jo«« (Lankester). Lower Devonian of Gaspd.
were attached to their fins as weapons of defence, and by
detached bony tubercles which protected their skin. These
remains are chiefly interesting as indications that two of the
great leading divisions of the class of fishes originated together.
In the Devonian age the Ganoids and Sharks, thus introduced
in the Silurian, may be said to culminate. The former, more
APPEARANCE CF VERTEBRATE ANIMALS. 123
especially, are represented by a great variety of species, some
of them nearly allied to their Silurian predecessors (Fig. io6),
others of forms and structure not dissimilar to those of the few
surviving representatives of the order, or altogether peculiar to
the Devonian (Fig. 107). So numerous are these fishes, and
of so many genera and species — and this not merely in one
region, but in widely separated parts of the world — that the
Devonian has not inaptly been called the reign of Ganoids.
Fig. 106. — Devonian Placoganoid Fishes {Pterichthys cormUus, Cephalaspis Lyelli).
As an illustration at once of the very peculiar forms of some
of these fishes and of their wide distribution, I figure here a
species of Cephalaspis (Fig. 105) found in the Lower Devonian
of Gasp^, in the same beds with some of the antique Devonian
plants described in the last chapter.
A new and interesting light has recently been cast upon some
of the most anomalous of the ancient fishes by the study of
the now rare and peculiar species of the group of Dipnoi.
Two of these, belonging to the genus Lepidosiren^ are the
124
THE CHAIN OF LIFE.
" Mud-fishes " of the rivers of tropical Africa and America (Fig.
1 08, b.) These creatures have an elongated and elegant form,
Vk,. It.!?.— I )evoniaa LepiJogxnoirl V.'A\\Gs,{Di/>liicanthus viaA Osteoie/is).—A{ttT i'a.gt:
and Nicholson.
and the body is covered with overlapping horny scales like those
of ordinary fishes ; but the pectoral and ventral fins are rod-like,
Fig. 108.— Modern Dipnoi,
rt, Ccratoaus Fostcrt. Australia, h, Lepidosiren annectns. Africa.
and are supported by simple cartilaginous rays, while the tail-
fin forms a fringe around the posterior part of the body.
APPEARANCE OF VERTEBRATE ANIMALS. 123
Unlike ordinary fishes, they have lungs as well as gills, and
their mouths are armed with sharp, bony, beak-like teeth (Fig.
115), with which they can inflict terrible bites on the small
fishes and frogs which furnish them with food. Their most
remarkable habit is that of burying themselves in the mud of
dried-up ponds, forming around themselves a sort of water-
chamber or "cocoon," in which they remain in a torpid state
until the return of the rainy season sets them free.
Another example of these Dipnoi is the Barramunda, or
Ceratodiis of the Australian rivers (Fig. 108^). This fish re-
sembles the Lepidosiren in many essential points of structure ;
KiG. 109. — Anterior part of the palate of Dtptertis. Showing the dental plates ut a.
Devonian. — After Traquair
but its fins have lateral rays, and are consequently of some
breadth, though of peculiar form, and its mouth is armed
with flat, pavement-like teeth, wherewith it browses on aquatic
grasses.
These modern fishes have enabled us to understand several
mysterious forms met with in the older rocks. In the first
place, they show the meaning of certain flat-toothed fishes, like
Dtptertis of the Devonian (Fig. 109), Conchodus of the Car-
boniferous (Fig. no), and Ceratodiis of the Carboniferous and
Trias (Figs, iii, 112), previously of very doubtful character.
Tlxese must all have been of similar structure and habits with
126
THE CHAIN OF LIFE.
the Barramunda, which is thus the sole survivor, perhaps itself
verging on extinction, of a group of herbivorous fishes introduced,
it may be, contemporaneously with the first streams affording
the requisite vegetable food, and which have continued almost
without improvement or deterioration to the present time.
Fig. ho.— Dental plate of Conchodus pUcatus (Dn.). Coal-formation of Nova Scotia.
Acadian Geology,
These fishes are, however, very closely connected with the
Ganoids, and there are some of these, with fringed fins and
overlapping scales, which, while regarded as true Ganoids,
resemble the Dipnoi v^ry closely.
Fk;. ii:. — Dental plate of Ceraiodus Barrandii. Coal-formation of Bohemia.
After Fritsch.
Again, certain huge fishes, whose remains are found in the
Devonian of Ohio,^ had jaws on the same plan with those of
Lepidosiren, but of enormous size and strength (Figs. 113, 114,
^ Dinkhthys Terrelli and D, Hertzeri (Newberry).
APPEARANCE OF VERTEBRATE ANIMALS. 127
115), so that in this and some other points of structure they
may be regarded as colossal Mud-fishes, and they must have
Fig. 112.— Dental plate of Ceratodns serraius. From the Trias.
had the same destructive powers, but on a far grander scale.
They were besides clothed with heavy armour of bony scales*
having some resemblance to that of those mailed fishes of
Fig. ii3.-Jaws of Dinkhthys /f^rtor/ (Newberry). Laterally compressed :
one-sixth natural size.
smaller size already referred to, and indicating that, huge
though they were, and formidable in destructive power, they
128
THE CHAIN OF LIFE.
also had enemies to be dreaded. These plates serve to ally
them with the Ganoids, as their jaws do with Lepidosiren.
We are thus enabled to see in the streams, lakes, and bays
of the Palaeozoic, harmless fishes, of the type of Ceratodus,
feeding on plants, and huge precursors of the Mud-fishes
Y
J ^
y
Fig. 114. 'Lov.'tr }2iW oi Dinichihys Ilefizcri One-sixth natural size.
darting from the depths, and provided with a dental apparatus
more formidable than that of any modern fi^" , sufficient to
pierce the strongest armour of the Ganoids, and to destroy and
devour the largest aquatic animals. These huge fishes, armed
with shears two or three feet in length, and capable of cutting
Fig. 115. — Jaws of Lepidosiren. Natural size. — After NewL err j'.
asunder scale, flesh, and bone, are the beau ideal of destructive
monsters of the deep, far surpassing our modern Sharks ; and
if, by means of supplementary lungs, they could breathe in air
as well as in water, they would on that account be all the more
vigorous and voracious.
APPEARANCE OF VERTEBRATE ANIMALS, ,29
Newberry has well remarked tl.at while in the Devonian the
Ganmds and D.pnoi were the real tyrants of the sea a"„eU
t: sl'^U:^•,;" ''^^-^-'-f-"-' '-y alread di^ii '
m sue though still abundant as to numbers, and are mere
limned to estuaries and fresh waters. Thus their depar ure
from power had already begun, and went on un.U in n'oder^
imes the proportion of Ganoids to ordinary fishes is according
.0 Gun.her nine out of 9,000. The Ca boniferol inde d^
very specially abounds in small Ganoids, though therlVe mant
large and formidable species. One of these 'smaller specfen
™r™ra./' ''""■°'=- *. f. ''. Sculpture of scales
magnified.
scales,
verv beautiful little fish, of fresh-water ponds and streams in
naturif V'"" "'^'^ Carboniferous age, is represented of t
natural size m Fi? itfi onri ;o «^* .
f J , ^* ' ^"^ ^s "ot a restoration beina
tt'tuTS Oft Ktiir ^™<^ '-"^ ''- "-' <^^"-^
The Sharks in the Carboniferous increase in number and
.mportance. Fig. rx, shows a few examples of thet teeth
and spines. In the Carboniferous, however, there is a Sat
130
THE CHAIN OF LIFE.
l)rcpondcrancc of those species with flat, crushing teeth fitted
for grinding shells,* which in diminishing numbers continue up
to the present time, when they are represented by the Port
Jackson Shark and a few other species. The increase toward
the modern time of the true Sharks =* with sharp cutting teeth, is
obviously related to the increase of the ordinary fishes which
i^
Fig. 117. — Teath and Spines of Carboniferous Sharks. Nova Scotiu.
(t, D I f>lodus penetrans 2mA D. acinaces. b, Psamwodus. c, Ctenofitychius c*-t.sitifi/\\
d, Spine, GyraaiHthus magnijicus. One-eightli natural nizs.^'Acadian Geology.
furnish them with food. Another curious difference, connected
probably with the same circumstance, is the fact that in the
sharp-toothed Sharks of the Carboniferous the two side fangs
of each tooth are the largest, or are exclusively developed
(Fig. 117, a), while in later periods the central point becomes
' Cesh'acionts. • Selachians.
APPEARANCE OF VERTEBRATE ANIMALS. 131
dominant, or is developed to the exclusion of the others (Figs
118, 119).
The Ganoids and Dipnoi still, however, occupy a very im-
portant place through the Mesozoic ages (Fig. 120), and it
is only at the close of the Cretaceous that they finally give
place to the Teleosts, or common fishes, which, though perhaps
more fully specialised in purely ichthyic features, have dropped
the reptilian characteristics of
their predecessors (Fig. 121).
It is interesting to observe that
these old-fashioned fishes had
culminated before the advent of
air-breathing Vertebrates, which
appear for the first time in the
Carboniferous, li is further to
be observed that groups of fishes
furnished wit'.i means of aiding
their gills by rudimentary lungs
were especially suited to waters
more charged with carbonic acid,
and less with free oxygen, than
those of more recent times.
This remark especially applies
to the mephitic and sluggish
streams aid lagoons of the
Carboniferous swamps, where.
m
the midst of a rank Vege- Fir.. 1 18.— Teeth of Cretaceous Sharks
, , . . iptodits s.nd Ftyc/wdus). — After Leidy.
tation and reeking masses of
decaying organic matter, the half air-breathing fishes and tie
amphibious reptilian animals met vith each other and found
equally congenial abodes. Thus, independently of the fact that
some of these fishes were probably vegetable feeders, it is not
altogether an accident, but .a wise adaptation, that caused the
culmination of the reptilian fishes and batrachian reptiles to
coincide with the enormous development of the lower forms
132
THE CHAIN OF LIFE.
of land-plants in che Devonian and Carboniferous. Another
curious illustration of the diminishing necessity for air-breathing
to the fishes, is the change of the tail from the unequally-lobed
or heterocercal form, which pre-
vailed in the Palaeozoic, to the
more modern equally-lobed
(homocercal) style in the Meso-
zoic. The former is better
suited to animals which have
to rise rapidly to the surface
for air, and is still continued
in some modern fishes, which
for other reasons need to ascend
and descend, or to turn them-
selves in the water; but the
homocercal form is best suited
to the ordinary fish, whether
Ganoids or Teleosts (Fig. 122).
It is curious also to find the
beginning of the dominancy of the ordinary fish to coincide with
Fig.
119.
-Tooth of a Tertiary Shark
(Carcfiarodon).
Fig. 120. — A Liassic Ganoid (/?«/<"<///«). Restored, — After-Nicholson.
tnat of the broad-leaved exogenous trees in the later Cretaceous,
and to precede immediately the appearance of the mammals on
the land ; all these changes being related to the purer air, the
APPEARANCE OF VERTEBRATE ANIMALS. 133
clearer waters, and the more varied continental profiles of the
later geological periods. Thus physical improvement and the
changes of animal and vegetable life are linked together by
correlations which imply not only design, but prescience,
whether we attribute these qualities to a spiritual Creator or
to mere atoms and forces.
Fig. 121.— Cretaceous Fishes of the modern or T ileoslian type.
Beryx Lewesiensis. English chalk, b, Poriheus molossus (Cope). A large fish
trom the American Cretaceous. One twenty-eighth natural size.
The history of fishes extends further through geological time
than that of any other Vertebrates, and is perhaps more com-
pletely known to us, in consequence of the greater facilities for
the preservation of their remains in aqueous deposits. If
we receive Pander's Conodonts as indicating a low type of
134
THE CHAIN OF LIFE.
cartilaginous fishes, these must have continued for vast ages
without any elevation, and struggling for a bare existence
amidst formidable Cuttle-fishes and Crustaceans, before, under
more favourable conditions, they suddenly expanded into the
high and perfect types of Ganoids and Sharks. If we reject
the early Conodonts, then the two last-mentioned types spring
together and suddenly into existence, like the armed men from
the dragon's teeth of Cadmus. They rapidly attain to numbers
and grandeur unexampled in later times, and become the lords
of the waters at the time when there was probably no Vertebrate
Fig. 122. — Modern Ganoids {_Polyptents. Africa. Lepidosteiis, A nerica).
life on the land. As the reptiles establish themselves on the
land and in the waters, the Ganoids diminish, but the Sharks
hold their own. At length the reign of reptiles is over, but the
Ganoids, instead of resuming their pristine numbers, give place
to the Teleosts, and become reduced to insignificance ; while
the Sharks, profiting by the decadence of the great marine
reptiles, remain the tyrants of the seas. This history is
strangely unlike a continuous evolution ; but we are anticipa-
ting facts which will fall to be discussed in a subsequent
chapter.
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CHAPTER VI.
THE FIRST AIR-BREATHERS.
WERE our experience limited to the animals whose
remains are found in the earlier Palceozoic rocks, we
might be unable to conceive the possibility of an animal capable
of living and breathing in the thin and apparently uncongenial
medium of air. More especially would this appear doubtful if
our experience of the atmosphere presented it to us as loaded
with carbonic acid, and less rich in vital air than it is at present.
Even the mechanical difficulties of the case might strike us as
considerable, in our ignorance of the capabilities of limbs.
Still, as time wore on, we should find this problem worked out
along three distinct lines of advancement— those of the Mol-
lusk, the Arthropod, and the Vertebrate, and in each of these
with different machinery, related to the previous locomotive
and water-breathing apparatus of the type.
Respiration under water depends, not on the water itself
but on the small percentage of free oxygen which it contains'
and this is utilised for the aeration of the blood of animals, by
that wonderful and often extremely beautiful apparatus of deli-
cate fibres or laminae penetrated with blood-vessels, which we
call a gill. Except those lowest creatures which aerate their
blood merely at the general surface of the body, all animals
capable of respiration in water are provided with gills in some
138 THE CHAIN OF LH^E.
form, though in many of the humbler types, Hke that of the
famiHar Oyster, the gills are used for the double purpose of
aerating the blood and, by their minute vibrating threads or
cilia, drifting food to the mouth.
In the great group of radiated animals, the Protozoa^ Calen-
terata^ and Echinodermaia, no air-breathing creature exists,
or, in so far as is known, has existed, so that this vast group
of animals is limited altogether to the waters ; and this is
undoubtedly one mark of its inferiority.
In the sub-kingdom of the Mollusks the highest class, that
of the Cuttle-fishes and Nautili, has been, singularly enough,
rejected as unfit for this promotion, though it was early intro-
duced, and attains to a high development of muscular energy
and nervous power. The group next in order, that of the
Snails and their allies, alone ventures in some of its families
to assume the 7'dle of air-breathing. As might be expected, in
creatures of this stamp the simplest means are employed to effect
the result. In the sub-aquatic species the gills are contained in
a chamber, where they are protected and kept supplied with
water. In the air-breathing species, this gill-chamber is merely
emptied of its contents and converted into an air-sac or func-
tional lung. Thus a rude and imperfect method of air-breath-
ing is contrived, which scarcely separates the animals that possess
it from their aquatic relatives, but which nevertheless gives to
us the beautiful and varied groups of the Land-snails and of
the air-breathing fresh-water Snails.
In the worms and Crustaceans the gills are placed at the
sides of the body, and connected with its several segments.
But the Crustaceans, like the Cuttle-fishes, though the highest
aquatic type, never become ^.ir-breathers. It is true some of
them, like the Land-crabs, liv« in the air ; but they retain their
gills, and have to carry with them a supply of water to keep
these moist.
But in order to elevate the Annulose type to the true dignity
of air breathing, three new classes had to be introduced, differing
THE FIRST AIR-BREATHERS. 139
altogether in their details of structure ; and all three seem to
have been placed on the earth about the same time. They are :
First, the Myriapods, or Gallyworms and Centipedes ; secondly,
the Insects ; and thirdly, the Arachnidans, or Spiders and
Scorpions.
In the Myriapods a system of air-tubes, kept open by elastic
spiral fibres, penetrates the body by lateral pores, thus retaining
the resemblance to the lateral respiration of the Crustaceans
and worms. In the Insects, where this type of structure rises
to its highest mechanical perfection, and where the animal
is enabled to be not merely an air-breather, but a flier, the
same system of lateral pores and internal air-tubes is adopted,
and is so extended and ramified as to give a very perfect respi-
ration. In the Spiders and Scorpions the system is the same,
except that in the latter and a part of the former the whole or
a part of the tracheal system becomes expanded into air-
chambers simulating true lungs.
Among the Vertebra):es, the fishes are bieathers by gills
attached to arches at the sides of the neck. But already in
the Devonian we have reason to believe that there were fishes
having the swimming-bladder opening into the back of the
mouth to receive air, and divided into chambers, so as to con-
stitute an imperfect lung. And here we have not, as in tlie
lower types, an adaptation of the old water-breathing organs,
but an entirely new apparatus. In the next grade of Verte-
brates we find, as in the Frogs, Water-lizards, etc., that the
young are aquatic and breathe by gills, while the adults ac-
quire lungs, sometimes retaining their gills also, but in the higher
forms parting with them. Thus in the vertebrates alone we
have true lungs, distinct structurally from gills ; and these
lungs attain to their highest perfection in the "birds and
mammals.
The oldest air-breathers at present known are insects allied
to the modern May-flies. They were discovered by the late
lamented Prof. C. F. Hartt in the plant-bearing shales of the
I40
THE CHAIN OF LIFE.
Middle Devonian of New Brunswick (Fig. 123). Tlie beds con-
taining them hold also a species of Eurypterus, an obscure Trilo-
bite, and a Crustacean allied to the modern Stomapods,i besides
a shell which may possibly be that of a Land-snail, to be men-
tioned in the sequel. They are also exceedingly rich in beau-
tifully-preserved remains of Devonian plants. The collection
made by Prof. Hartt is limited to a few fragments of wings ;
but these, in the skilful hands of Mr. Scudder, have proved to
-*-~A
itSiit^-^
_U~^ '~T~i r--^-
^^"•"■v
^X^
Fig. 123.— Wings of Devonian Insects, Middle Devonian of New Brunswick.
a, Platephemera nniiqua (Scudder). b, Hontothetus fossilis (Scudder). c, Lithen-
tomum Harttii (Scudder). d, Xenoneura antiguorum (Scudder).
be rich in geological interest. One is a gigantic Ephemera or
May-fly, which must have been five inches in the expanse of
the wings, which are more complex in their venation than
those of its modern allies (Fig. 123, a). Another presents
peculiarities between those of the May-flies and Dragon-flies
(Fig. 123, b). A third is a Neuropter, not belonging to any
known family, but allied to some in the Coal- formation (Fig.
123, c). A fourth has the remarkable peculiarity of showing
traces of a musical or stridulating apparatus, similar to that
1 Arnphipeltis paradoxus of Salter.
THE FIRST AIR-BREATHERS. 141
of modern crickets (Fig. 123, d). Two others are represented
by mere fragments of wings, i-nsufficient to determine their
affinities with certainty. No other insects so old as these have
been discovered elsewhere; but it is to be borne in mind that
no other locality rich in Devonian plants has probably been
so thoroughly explored. The hard slaty ridges containing
these fossils are well exposed on the coast near the city of St.
John, and Messrs. Hartt and Matthew of that city, acting, I
believe, in concert with and aided by the Natural History
Society of the place, not only searched superficially, but removed
by blasting large portions of the richest beds, and examined
every fragment with the greatest care. Their primary object
was fossil plants, of which they obtained magnificent collec-
tions ; and it is scarcely possible that the insects could have
been found but for the exhaustive methods of exploration
employed.
It is interesting to observe, respecting these oldest insects,
that they all belong to those families which have jaws, and not
suctorial apparatus, that they are not of those which undergo a
complete metamorphosis, and that their modern congeners pass
their larval stage in the water. Thus the waters gave birth to
the first insects, and their earliest families were not of those
which suck honied juices or the blood of animals, or which
pass through a worm-like infancy. These groups belong
apparently to much later times.
On one of the specimens collected by Messrs. Hartt and
Matthew, and placed by them in my hands, is a spiral form
which m every particular of external marking resembles a
genus of modern West Indian Land-snails.i I have hesitated
to describe it, as the structure is lost and the form imperfect ;
but I cannot help regarding it as an indication that this group
of land animals also will be traced back to the Devonian age.
Ascending from the Devonian to the Carboniferous, we at
c/ ?/""^ Strephia, I have provisionally named the St. John species
Strephttes erianus. ^ ^
142 THE CHAIN OF LIFE.
once find ourselves in the midst of air-breathers of various
types. Here are Myriapods, insects of several orders, Spiders,
Scorpions, Land-snails, and Batrachian reptiles, and these of
many species, and found in many localities widely separated.
We can thus people those dark, luxuriant forests, to which we
owe our most valuable beds of coal, with many forms of life; and
as most of these belong to tribes likely to multiply abundantly
where food was plentiful, we can imagine multitudes of Snails
and Millepedes feeding on succulent or decaying vegetable
matter, swarms of insects flitting through the air in the sunnier
spots, while their larvae luxuriated in decaying masses of leaves
or wood, or peopled the pools and streams. In like manner,
in imagination we can render these old woods vocal with the
trill of crickets and with the piping or booming of smaller and
larger Batrachians. Let us now, in accordance with our plan,
inquire as to the nature of these early air-breathers and the
fortunes of their families in the geological history.
The Land-snails known as yet in the Carboniferous are
limited to four species, belonging to as many genera, all
American and related to existing American forms. The two
earliest known are represented in Figs. 124 and 125.^ One of
them is a Pupa, or elongated Land-snail, so similar to modern
forms that it does not merit a generic distinction, and is indeed
very near to some existing West Indian species. The other is
in like manner a member of the modern genus Zonites. These
are from the Coal-formation of Nova Scotia, and the Pupa must
have been very abundant, as it has been found in considerable
numbers in a layer of shale, and in the stumps of erect trees,
in beds separated from each other by a thickness of 2,000 feet
of strata. The Zonites is much more rare. The other two
species occur in the Coal-field of Illinois, and have been de-
scribed by Bradley. One of these is a Pupa still smaller than
P. vetusta, and, like some modern species, with a tooth-like
^ The enlarged figure of Pttpa vetusta is too much elongated, and the
aperture is somewhat conjectural, as it is usually crushed.
THE FIRST MR-BREATHERS. ,4,
process on the inner lip. Tlie other has been placed in a new
genus, but IS very near to some of the smaller American Snails
«, Matural .i^.. I, Magnified. ., Apex, rf, Sc„lp,„re. Enlarged.
stni living. Its most special character is a plate extending from
the mner hp over half the aperture, a contrivance for prote"
».Shd,. Enlarged; ,h.l,„,b.,„„ shows .he „n,„a, sua. .. Sculp„„e. Enlarged
tion still seen in some modern forms. Thus the Land-snails
^ Daxvsonella of Bradley.
14+ THE CHAIN OF LIFE.
come on the stage in three familiar generic forms, similar to
those which still live, but all of small size, indicating perhaps
that the conditions were less favourable for such creatures than
those of the temperate and warmer climates at present. It may
seem a small step in advance for Sea-snails to lose their gills
and to become Land-snails, and this without any elevation ol
their general structure; but it must be borne in mind that we
have here not only the dropi)ing of the gills for an air-sac, but
profound changes in teeth, mucous glands, shell, and other par-
ticulars, to fit them for new food and new habits. Tt is also
singular that the Land-snails at once ai)pcar instead of the
intermediate forms of the air breathing fresh-water snails.
These last may, however, yet be found. ^
The Millepedes, like the Land-snails, were f;rst found in the
Coal-formation of Nova Scotia, but species ha/e since been
discovered not only in Illinois, but also in Greai Dri^^ain and
in Bohemia. In Nova Scotia alone two genera and five dis-
tinct species have been found, all in the interior of erect trees,
to which these creatures probably resorted for food and shelter
(Fig. 126). All the species yet known are allied to the modern
Gallyworms, though presenting distinct features which seem to
separate them as a distinct family,^ and were probably vegetable-
feeders. One of the Western species has the peculiarity, un-
known among its modern successors, of being armed .vith long
spines.^ The moist, equable climate and exuberant vegeta-
tion of the Coal-period would naturally be very favourable to
Millepedes, and it is likely that the discoveries made as yet
give but a faint idea of their actual abundance. It is not
improbable that they subsequently declined, as we know of
none between the Carboniferous and the Jurassic, and they
do not seem to have improved up to the modern period. The
1 Recent large acquisitions of material from the erect trees of the South
Jopgins may, I hope, soon enable me to add to the number of species of
L^nd-snails of the Carboniferous.
* ArchiulidcB of Scudder.
* Euphobeda armii^era (Meek and Worthen), from Illinois.
THE FIRST AIR-BREATHERS.
145
Carnivorous Myriapods, however, or Centipedes proper, a
higher and essentially distinct type, are not known until much
more recent t. ^es.
The insects of the Carboniferous as yet known, belong to
three out of the ten or more orders into which (he class is
divided. One of these is represented by a number of species
of Cockroach, another by May-flies and a Dragon-fly, and
another by some weevil -like Beetles. The Cockroach is cha-
racterised by Huxley as one of the " oldest, least modified.
F.w. 126. — Millepedes. From the C^ al-formation.
rt. XyloHus sigillnrife (Dawson). /', Architilus xyloHoidcs (Scudder), Anterior
segmtn's. iinlarged. c, X./arctus (Scudder). Caudal portion. Enlarged.
and in manyAvays most instructive forms of insects;" and both
he and Rolleston take its anatomy as typical of that of the
class. That these creatures should have abounded in the
Coal-period we need not wonder, when we consider the habits
of those that infest our houses, and when we further bear
in mind the number of species, some of them two inches in
length, that exist in tropical climates. So many species ot
this family have been found in the Coal-formation on both
sides of the Atlantic,^ that we may fairly regard them as con-
stituting one of its most characteristic features, and as probably
^ About fifty in all, as I learn from Mr., Scudder.
. THE CHAIN OF LIFE.
„=,= found in the Coal-formation of Scotland. 1 lie may mc
7riw<^) are represented in the Carboniferous by several
tffrg Secies. 'Xhat of which the wing is shown in Fig
rJ mi!t have been seven inches in expanse of ^vmgs The
habitrof the modem May-flies show us how animals of thij
F,a. ,„._Wing.of Cockro^h... From the Coal-focmauon.
a. ArcMmulMns -^'«^«''J_<^"Xm (S>;udd.r).
.roup living as larv:e in the streams and lakes must have
Sd l4 supplies of food to fishes, and when mature
must have emerged from the waters m counttes my™^ ■
filling the air for the brief term of their existence in the per
feet ftate. A single specimen, found in the Coal-Seld of Cape
Breton is recognised by Scudder as the larva of a Dragon-fly
mg x'.Q), and he informs us that this predaceous and beau-
'I'tre-Ae hawks of the class /««^.-flitted on the ba.k
of Carboniferous streams. These two famihes of May flies
THE FIRST AIR-BREATHERS.
M7
and Dragon-flies represent another insect order.^ The Coal-
measures of Saarbruck have afforded several species allied to
the white ants {Tennites) insects which must have found abun-
dant scope for their activity in the dead trees of the carboni-
ferous forests. The occurrence of beetles, ^ especially of the
weevil family, which have as yet been found only in Europe
might have been expected, considering the habits and modern
distribution of this group. It has been asserted that moths ^
have been found in the Carboniferous ; but the proof of this,
"" 11-^ -J : ■ tJ - j-U ^ - . ■ . — I — iM j:j'J*
Fig. 128. — Wing of May-fly (^Haplophlebium Bamesii, Scudder). From the
Coal-formation.
SO far as known to me, is the occurrence ot leaves, noticed
by Sternberg, with markings similar to those made by the larvae
of minute leaf-mining moths. This, however, is uncertain evi-
dence. If we consider the orders of insects not found in the
Coal-formation, we can perceive good reasons for the absence
of some of them. Those containing the lice and fleas, and
other minute and parasitic insects, we can scarcely expect to
find. The bees and v isps, and the butterflies and moths, are
1 Ncuroptera, ^ Coleoptera. ^ Titie.c,
L 2
,^g THE CHAIN OF LIFE.
little likely to have been present where there were scarcely any
flowering plants ; but such groups as those of the two-wmged
flies, the pLt-bugs and the ants, we might have expected bu
for the fact of their being highly specialised forms, and for
that reason likely to have appeared lator^ J'? "I's elrl
as yet no haustellate or suctorial msects known m this ear y
period. Plausible theories of the phylogeny of '"sects a e
not wanting ; but they do not well suit the known facts as to
their first appearance- and perhaps we may venture without
much blame to apply to the insects of the Coal-period the
remark made by Wollaston with reference to the nch insect
Tna of the isokted rock of St. Helena: "To a mind which.
(
Fic. ..9.-AbloniInal part of the larva of a Carboniferous Dragon fly ^LiMluIa
carbonaria, Scudder),
like my own, can accept the doctrine of creative acts as not
necessity • unphilosophical,' the mysteries [of the existence
of these species in an island so remote from other land], how-
ever greatfbecome at least conceivable ; but those which are
not atle t; do this may, perhaps, succeed .["ff «^^°°;^
special theory of their own, which, even if it does not satisfy
all the requirements of the problem, may at least prove
convincing to themselves."
The suctorial insects make their first certain appearance in
the Jurassic ; and the magnificent Sphinx Moth m Fig. 130 is
J One hio^hly specialised Carboniferous insect «'=;;"">' ,|[?;';'!:;i\ """^
Prc^pLml of Bmngniart, a relative of the modern Walkmg-sueks.
THE FIRST AIR-BREATHERS.
149
an example of the magnitude and perfection to wliich that
tribe attained in the age of the Solenhofen state ; though
V/eyenburgh, who describes it, fancies that he sees evidence
that it may, unlike any modern moths, have been provided
with a sting. The most perfect and beautiful fossil butterfly
known to me is that represented in Fig. 131, from a photo-
graph kindly given to me by Mr. Scudder. It is from the
Fig. 130. — A Jurassic Sphinx-moth {Sphinx Snellen', Weyenburgh).
Tertiary rocks of Western America, and is laid out in stone
as neatly as if prepared by an entomologist, while its preserva-
tion is so perfect that even the microscopic scales on the wings
can be made out. It belongs to one of the highest types of
modern butterflies, that to which the VanesscE belong, but with
some points of structure pointing to the lower group of the
"Skippers" {Hesperiadce) . Scudder remarks that ->vhile the
fore-wings resemble 'hose of the former group, the hind-wings.
ISO
THE CHAIN OF LIFE.
look more like those of the latter ; and this seems to be a
common character of two or three others of the few fossil
species known, none of which are older than the Tertiary.
We know too little of the spiders and scorpions of the
Carboniferous to say more than that they closely resemble
modern forms. One of the scorpions is represented in Fig. 132 ;
and the only spider certainly known, which is from Silesia, is
said to belong to the group of the hunting or trap-door spiders
[Lycosa)}
The Batrachians of the Coal are its most characteristic and
Fig. 131. — Pi.\\YiOCGncV>\MQxAy {Proiityas perseJ>hoHe, Scudder). From Colorado.
remarkable air-breathers, — especially so as the precursors of the
reptiles of the Mesozoic age. Cope in a recent summary
enumerates no less than thirty-nine genera and about one
hundred species ; and to these have to be added at least a
dozen more recently discovered in Europe ; though it was
only in 1841 that the first indications of such creatures were
found, and were then regarded by geologists with the same
scepticism which some of them still apply to Eozoon. The
* Protolycosa (Roemer).
THE FIRST AIR-BREATHERS. 151
first trace ever observed of batrachians in the Carboniferous
consisted of a series of small but well-marked footprints found
by the late Sir W. E. Logan in the Lower Carboniferous shales
of Horton Bluff, in Nova Scotia. In that year this pains-
taking geologist had examined the coal-fields of Pennsylvania
and Nova Scotia, with the view of following up his important
discovery of the StigmaricB, or roots of Sigillaria, as accom-
paniments of the coal-underclays. On his return he read a
paper, detailing his observations, before the Geological Society
ot London. In this he mentioned the footprints in question
Fig. 122.— Caxhomiexows Scot\aotv {Eoscor/>ius carbonnrius, Meek and Worthen).
Illinois.
but the paper was published only in abstract, and the import-
ance of the discovery was overlooked for a time, the anatomists
evidently being shy to acknowledge the validity of the evidence
for a fact so unexpected. Fig. 133 is a representation of another
slab subsequently found in beds of the same age in Nova
Scotia, and which may serve to indicate the nature of Sir
William's discovery. In consequence of the neglect of this
first hint by the London geologists, the discovery of bones of
a batrachian by von Dechen at Saarbruck in 1844, and that of
footprints by King in Pennsylvania in the same year, are usually
represented as the first facts of this kind. My own earliest
discovery of reptilian bones in Nova Scotia was made in 1844,
THE CHAIN OF LIFE.
though not published till some time afterward, and was fol-
lowed up by further collections in company with Sir Charles
Lyell in 1851, at which time also the earliest land-snail was
found, and in the following year the first millepede. Since
that time the progress of discovery has been astonishingly
rapid, and has extended over most of the principal coal-areas
on both sides of the Atlantic.
Fig. 133. — Footprints of one of the oldest known Batrachians, probably a species ot
Dendrcrpeton From the Lower Carboniferous of Parrsboro', Nova Scotia. Upper
figure natural size.
We may, for convenience, call these animals reptiles, but
they are regarded as belonging to that lower grade of reptilian
animals, the Amphibians or Batrachians, which includes the
modern frogs and newts and water-lizards.^ Still it would be
doing great injustice to the carboniferous reptiles not to say,
^ MenoJ>oma, Menobranchus, etc.
THE FIRST AIR-BREATHERS. 153
that while related to this low type, they presented a much
greater range of organisation than it shows at present, evincing
a capability to fill most of the places now occupied by the
true reptiles. Some of them were aquatic, and with limbs
rudimentary or little developed, but many of them walked on
the land, and were powerful and predaceous creatures. They
had large and complex teeth, they were protected by external
bony plates, and some of them had in addition a beautiful
covering of bony plates and spines, and ornamental lappets.
Many had well-developed ribs, indicating a condition of respi-
ration much in advance of that in the ribless batrachians.
Some of them attained to size and strength rivalling those of
the modern alligators, while some of the smallest species
exhibit characters approaching in some respects to the lizards.
Perhaps the most fish-like of these animals are those first dis-
covered by von Dechen {Aj'c/iegosauriis, Fig. 134). Their long-
heads, short necks, supports for gills, feeble limbs and long
flat tail, show that they were aquatic creatures, presenting
many points of resemblance to the Ganoid fishes which must
have been their companions. Yet they show what no fish can
exhibit, fore and hind limbs with proper toes, and the complete
series of bones that appear in our own arms and legs, while
they must have had true lungs and breathed through nostrils.
So different are they from the fish in details, that a single limb
bone, a vertebra, a rib, or a fragment of a skull bone, suffices
to distinguish them. Much has been said recently of the
genesis of limbs ; and here, as far as now known, we have the
first true limbs ; but it is scarcely too much to say that the
feet of Archegosaurns differ more from the fins of any car-
boniferous fish than they do from the human hand ; while it is
certain that the feet which made the impressions represented
in Fig. 133, on the lowest beds of the Carboniferous, or fhat
from the upper coal-formation represented in Fig. 139, were
not less typical or perfectly formed feet than those of modern
lizards.
154
THE CHAIN OF LIFE.
Leaving these fish-like forms, we find the remainder of the
carboniferous reptiles to diverge from them along three lines.
The first leads to snake-like creatures, destitute of limbs,
and which must have been functionally the representatives of
Fig. 134. — Archegcuiunis Decheni.
Head and anterior limb reduced. Coal-field ot
Saarbruck.
the serpents in the Palaeozoic, though batrachian in their
affinities (Fig. 135). They are found both in Europe and
America ; and Huxley describes one from Ireland more than
Fig. 135. — Ptyonius. A Snake-like Amphibian. Coal-measures of Ohio. — After Cope.
twenty-one inches long, and with over one hundred vertebrae.^
Some extraordinary traces are found on the sandstones of the
coal-formation,^ which appear to indicate that there may have
^ Ophiderpeton Brouinriggii. ^ Diplichnites.
THE FIRST AIR-BREATHERS.
155
been species of this type much larger than any represented by
skeletons, and with bodies perhaps six inches in diameter. It
is not unlikely that they had the habits of the modern water-
snakes.
A second line leads upward to large crocodile-like creatures,
with formidable teeth, strong bony armour, and well-developed
limbs {Labyrmthodontia, Figs. 136, 137). Some of them must
have attained a length of ten feet. They were lizard-like in
form, could walk well, as is seen from the footprints of some
of the species which present a considerable stride, and moved
Fic. 136. — A large Carboniferous Labyrinthodont {Bajihetes plnniceps, Owen).
a. Anterior part of the skull, viewed from beneath. One-sixth natural size, b. One of
the largest teeth, natural size.
over mud without the belly touching the ground. Their tails
were long, and probably useful in swimming. Their heads
were flat and massive, and their teeth were strengthened by a
remarkable folding inward of the outer plate of enamel
(Fig. 137 h). The belly was protected by bony plates and
closely imbricated scales. In some of the species at least the
upper parts were clothed with horny scales, and the throat and
sides were ornamented with pendant scaly fringes or lappets.
Their general aspect and mode of life must have resembled
^ There are known in some of the smaller species, but not as yet in the
larger.
156
THE CHAIN OF LIFE.
those of modern alligators ; and in the vast swamps of the
Coal-period, full of ponds and sluggish streams swarming with
fish, they must have found a most suitable abode. While rigid
anatomy may ally these animals rather with the batrachians
than the true reptiles, it is evident that their great size, their
capacity for walking with the body borne well above the ground,
their bony and scaly armour, their powerful teeth and their
capacious chests, with well-developed ribs, indicate conditions
Fig. 137. — Baphetes planiceps (Owen).
a. Fragment of maxillary bone showing sculpture, four outer teeth, and one inner tooth.
Natural size, b. Section of inner tooth. Magnified, c. Dermal scale. Natural size.
of respiration and general vitality quite comparable with those
of the highest modern members of the class Reptilia.
The third line of progress leads to some slender and beau-
tiful creatures (Mkrosaurta), chiefly known to us by remains
found in erect trees, and which resembled in form and habits
the smaller modern lizards. They have simple teeth, a well-
developed brain-case, limbs of some length, and bony and
THE FIRST AIR-BREATHERS.
157
scaly armour, the latter in some cases highly ornate.^ They
were probably the most th-^roughly terrestrial, and the most
active of the coal batrachians, if indeed they were not strictly
intermediate between them and the lizards proper. Fig. 138
a
^w-mpv-wmf^^^
p^^^W^A.V)i^ :nJl5MM.14.^>!j^^;.
e O
if
/,.:vr- ■/; . /-^ ^_ p.- '^^■'1*^
Fig. 138.— a lizard-like Amphibian (JJylonomus aciedentatus).
a. Maxillary bone ; enlarged. d. Section of tooth ; magnified.
h. Mandible ; enlarged. ^. Scale ; natural size and magnified.
c. Teeth ; magnified, showing front and Fide /, Pelvic bone(?) ; natural size.
view of ordinary tooth and grooved /r Rib ; natural size.
anterior tooth. A. Scapular bone (?) ; natural size.
t. Palate ; natural size.
shows some fragments of one of these animals ; and the animal
represented in Fig. 139, recendy figured by Fritsch, probably
belongs to this group.
1 Hylonomus»
158
THE CHAIN OF LIFE.
Fig. i^g.—SteUiosaurus lotigicostatiis (Fritscli). Upper Coal-formation of Bohemia.
The Labyrinthodonts of the Carboniferous continue upward
into the Permian, where they meet with the true reptiles ; and
in the earlier Mesozoic some of the largest and most typical
THE FIRST AIR-BREATHERS. 159
examples are found. ^ But here their reign ceases, and they
give place to reptiles of more elevated tyi)e, whose history we
must consider in the next chapter.
Nothing can be more remarkable than the apparently sudden
and simultaneous incoming of the batrachian reptiles in the
Coal-formation. As if at a given signal, they came up like
the frogs of Egypt everywhere and in all varieties of form. If,
as evolutionists suppose, they were developed from fishes, this
must have been by some suddrn change, occurring at once all
over the world, unless indeed some great and unknown gap
separates the Devonian from the Carboniferous — a supposition
which seems quite contrary to fact — or unless in some region
yet unexplored this change was proceeding, and at a particular
time its products spread themselves over the world — a supposi-
tion equally improbable. In short, the hypothesis of evolution,
as applied to these animals, is surrounded with geological
improbabilities.
A remarkable picture of the conditions of Palaeozoic hnd
life is presented by the occurrence of remains of reptiles.
Millepedes and land-snails in such erect trees .^ that repre-
sented in Fig. 140. In the now celebrr'jd section of the
South Joggins in Nova Scotia, trees of this kind occur at
more than sixty different levels ; but only in one of these have
they as yet been found to be rich in animal remains. Fortu-
nately this bed is so well exposed and so abundant in trees,
that I have myself, within a few years, removed from it
about twenty of them, the greater number affording remains
of land animals.
The history of one of these trees may be shortly stated thus.
It was a Sigillaria, perhaps two feet in diameter, and its stem
had a dense and imperishable outer bark, a soft cellular inner
bark liable to rapid decay, and a slender woody axis not very
durable. It grew on the surface of a swamp, now represented
by a bed oi coal. By inundations and by subsidence, this
^ Mastodonsaurus or La^yrinthodon,
i6o
THE CHAIN OF LIFE.
swamp was exposed to the invasion of muddy and sandy
sediment, and this went on accumulating until the stem of the
tree was buried to the height of about nine feet, before v.^Mch
time it was no doubt killed. After a time the top decayed and
fell, leaving the buried stump imbedded in the sandy soil,
which had row become dry, or nearly so. The trunk decayed,
its inner bark and axis rotting away and falling in shreds into
the bottom of the cylindrical hole, about nine feet deep, once
occupied by the stem, and now kept open like a shaft or well
by the hard resisting outer bark. The ground around this
opening became clothed with ferns and reed-like Calamitcs,
partly masking and concealing it. And now millepedes and land
J'lG. 140. — Stction showing the position of r\n erect Sigillaria, conUiining remains ox
land aniniuls.
1. Undcrclay, with rootlets of Stigmaria, resting on gray shale, with two thin coaly
seams.
5. (iray sandstone, wiih eicv,: trees, Calamitcs, and other stems : 9 feet.
■),. Coal, with erect tree on its surface: G inches.
n. Underclay with Stigmaria rootlets.
a, Calamites. c, Stigmaria roots.
i). Stem of plant undetermined. a', Krect truik, 9 feet high.
snails made the buried trunk a home, or fell into it in their
wanderings; and small reptiles sporting around, in pi'isuit of
prey, or themselves pursued, stumbled into the open pitfall,
and were unable to extricate themselves, though I have found
in some of the layers in these trees trails which show that these
THE FIRST AIR-BREATHERS. i6r
imprisoned reptiles had wearily wandered round and round, in
the vain search for means of exit, till they died of exhaustion
and famine. The bones of these dead reptiles, shells of land-
snails and crusts of millepedes, accumulated in these natural
coffins, and became mixed with vegetable debris falling into
them, and with thin layers of mud washed in by the rains; and
this process continued so long that a layer of six inches to a
foot in thickness, full of bones, was sometimes produced. At
length a new change supervened, the area was again inundaud
and drifted over with sand, and the hollow trunk was filled to
the top and buried under many feet of sediment, never to be
re-opened till, after the whole had been hardened into sand-
stone and elevated to form a part of the modern coast, when
\'u:. r-inrr.— Section of b.isc of erect Sigillaria, containing remains of land animals.
n^ Mineral charcoal. /-, Dark-coloured s.anilstone, with plants, Lxnes, etc. c, (Iray
sandstone, with Calaniites and Cordaites.
the old tree and its forest companions which had shared the
same fate with it, are made to yield up their treasures to the
gc'ologist. This history is no fancy picture. It represents the
results of long and careful study of the beds holding these erect
trees, and of the laborious extraction of great numbers of t'^em
and the breaking-up of their contents into thin flakes, to be
carefully examined wi'h the lens under a bright light in search
of the relics they con tamed. Fig. 1 1 in Chap. I. represents
the extraction of one of these trees, which happened to be
partially exposed by the wasung of the cliff; but many others
had to be laboriously mined out of the rock by blasting with
gunpowder.
It is evident that the combination of circumstances referred to
M
j62 the chain of life.
above could not often occur ; and it is therefore not wonderful
that only in one place and one bed has evidence of it been
found, and that even in this some of the trees have been filled
up at once by sand and clay, or so crushed by falling in or
lateral pressure, that they could receive no animal remains
In one respect this is a striking evidence of the impcrfectiori of
the geological record, since, but for what may be called a
fortunate accident, many of the most interesting inhabitants cf
the coal forests might have been altogether unknown to us.
On the other hand, it shows how strange and unexpected are
the ways in which the relics of the old world have been pre-
served for our inspection, and that there is probably scarcely
any animal or plant that has ever lived of which some fragment
does not exist, did we know where to look for it.
It may be well to remark, in closing this chapter, how many
new forms of life, air-breathing and o^h-wise, make their first
appearance in the Carboniferous, and have continued to prevail
until now. Here we find the first Amphibians, Scorpions,
Spiders, Myriapods, Orthotropous and Coleopterous insects
and ten-footed Crustaceans. In the latter group Woodward
has recently described the oldest known crab, from the Coal-
formation of Belgium.
M 2
-J ■?
J- ,"**
as ^
- c
/. .,;
X ?
I i
h li
X fj
■'«W|iiiii''l'«|!'!i'i'li! ''''ill" ■11,
''''i>'iijiiiii<iii.iiiiiiiiiiii!i
CHAPTER VII.
TIIK EMPIRE OF THE GREAT REPTILES.
HAD we lived in the Carl^oaiferous period, we might liave
supposed that the line of the great Labyrinthodont
IJatrachians would have been continued onward and elevated,
perhaps, in the direction of the Mammalia, to which some
features of their structure point. liut we should have been
mistaken in this. The Lal^yrinthodonts, it is true, extend into
the Trias ; but there is ])erhaps a sign of their coming degra-
dation in the appearance in the Permian of the first known
mud-eel, a humble Batrachian form allied to the Newts and
Water-lizards.^ Their s])ecial peculiarities are dropped in the
Mesozoic in favour of those of certain small and feeble lizard-
like animals, appearing first in the Carboniferous, and more
manifestly in the Permian, and which are the true forerunners,
though they can scarcely be the ancestors, of the magnificent
rei)tilian species of the Mesozoic, which have caused this
period to be called "the age of reptiles."
The leading reptilian animal from the European Permian
has long been the Proterosauruy.. from the cnpi)er slates of
Thuringia (Fig. 141), a rei)tile of lizard-like form, with well-
developed limbs, and attaining a length of three or four feet.
It resembles more nearly those large modern lizards known as
^ J'alicosiii'ii In'ineftii of (jcinilz.
1 66
THE CHAIN OF LIFE.
" Monitors," than any other existing form. The forc-Iimb
represented in the figure foreshadows very closely the bones
of the human arm and hand. Besides this we find in the
Permian certain lizards {Theriodonts of Owen) which present
the remarkable and advanced ])eculiarity already predicted
by some Carboniferous Microsauria/ of having distinct canine
teeth, producing adivision into incisors, canines,
and molars, in the manner of the Carnivorous
([uadrupeds, which they seem also to have
resembled in some other parts of their skele-
tons. It is not impossible that the foot-
prints in the Permian sandstones of Scotland,
which have been referred to tortoises, were
those of animals of this type. Cope has
recently described from the Permian of Texas
a number of reptiles which have the complex
dentition of the Theriodonts, and others which
simulate that of Herbivorous mammals, by the
possession of flat grinding teeth supposed to
be adapted to vegetable food.''' The teeth of
all these Permian reptiles were set in sockets,
also an advanced peculiarity. Thus already
in the Permian, before the final decadence
of the Carboniferous flora, and while the
Palaeozoic invertebrates still lingered in the
sea, the age of reptiles dawned, and gave
])romise of its future greatness by the as-
sumption on the part of reptilian species of
structures now limited to the Mammalia.
But the great Mesozoic reptiles were not fully enthroned, till
the Permian, an unsettled and disturbed age, characterised by
great earth movements, had passed away, and until that period
of continental elevation, with local deserts and desiccation, and
much volcanic action, which we call the Trias, had also passed.
^ llyleopelon. ^ Diadictes and Bolasaiiriis (Cojie).
Y\r,. 141. — Arm of
Proterosauriis
Sfieneri. Re-
duced. Permian.
THE EMPIRE OF THE GREAT REPTH.ES. 167
Then .in the Jurassic and early Cretaceous the reptiles culmi-
nated, and presented features of magnitude and structural
complexity unrivalled in later times. At the same time the
Labyrinthodonts disappear, or are degraded into the humble
stations which the modern Batrachians now occupy.
To understand the reptiles of this age, it will be necessary
to notice the subdivisions of their modern representatives. The
true reptiles now existing constitute the following orders : —
T, the Turtles and Tortoises (C/ie/om'a) ; 2, the Snakes (0/>/ii-
dia) ; 3, the Lizards {Lacertilia) ; 4, the Crocodiles and
Alligators {Crocodilia). All of these, except the snakes, are
well represented among Mesozoic fossils ; but we have in this
middle age of the earth's geological history to add to them
from five to seven orders now altogether extinct, and these not
I'k;. 142.— Skeleton of hhthyosnurus. Li;is. ICngland.
of low and inferior organisation, but including species far in
advance of any now existing both in elevation and magnitude,
and constituting the veritable aristocracy of the reptile race.
It will best serve our purpose here to consider chiefly these
perished orders and their history, and then to notice very
shortly those that now survive.
The first of the extinct orders is that of the great Sea-lizards,^
of which the now familiar Ichthyosaurus and Plesiosauriis ot
the English seas, to be seen in all museums and text-books,
are the types (Figs. 142, 1420; and i^2b). These were marine
animals of large size, but not fishes or amphibians. They were
true air-breathing reptiles, but with paddles for swimming
instead of feet, and some of them with long flattened tails
for steering and propulsion. They bore, in short, precisely
^ Enalcosauria^ including Ichthyoptcry^ia and Saiiropterygia.
i68
THE CHAIN OF IJFE.
the same relation to the other members of the class Rcptilia
which the Whales and Porpoises bear to the ordinary ([uadru-
peds. Some of these animals are believed to have been fifty
or sixty feet in length, thus rivalling the Whales, while others
Fig. 142a.— Head of /V/o.vrt//;7/i-. Jurassic. Mucli reduced.
were of smaller dimensions, like the Porpoises and Dolphin?.
Some, like the Ichthyosaurus and Pliosaurus (Fig. 142^), were
strongly built and powerful swimmers, and able to destroy the
largest fishes, while others, like Pksiosaurus, had the body
short and compact, the head small, and the neck long and
,^^^^
Fig. i^2lj.—V:iM\^oi J'lesiosattrus OxoHiensis. Jurassic- After Pliiliips. One-tenth
natural size.
flexible, and probably preyed on small animals near the
borders of the waters. Catalogues of British fossils alone
include about thirty species of Enaleosaurs, which haunted
the coasts of Mesozoic Europe, a wonderful fact, when we
consider the absence of these creatures from the modern seas,
and the probability that only a fraction of the species are yet
known to us.
THE EMPIRE OF THE GREAT REPTILES. 169
Another remarkable group is that to which Cope has given
the name of ryihi)no7norpha, and which he regards as allied
to the serpents, or as gigantic sea-serpents jjrovided with
swimming paddles, but which Owen considers more nearly
connected with the lizards. In either case they constitute a
group by themselves, remarkable not only on account of their
anatomical affinities with animals so unlike them in general
port, but also for their enormously extended length and formid-
able dentition (Fig. 143). Such animals as the Mososanrus
of Maestricht and Clidastes of Western America may have
exceeded in length the largest Ichthyosaurs and the most
bulky of living Cetaceans, though their slender forms and
numerous vertebrae remind one of the semi-fabulous sea-
serpent, rather than of any known animal of any geological
age. They were characteristic of the Later Mesozoic, more
especially of the Cretaceous period, and must have been
formidable enemies to the fishes of their time.
Owen has formed two orders ^ for the rece])tion of some
remarkable extinct reptiles of this age, found especially in
South Africa and India, but also in Europe and America.
The first includes large lizard-like animals having horny jaws
like those of turtles, and in some of the species with great
defensive tusks (Fig. 144). Their mode of life is not well
known, but they may have been peaceable and harmless vege-
table feeders. The second has been already referred to, in
connection with the Permian, where it first appears, though it
is continued in the Trias (Fig. 145). The resemblance of
the skulls of these creatures to those of Carnivorous mammals
is very striking, and nothing can be more singular than their
early appearance and their decadence before the advent of
those Tertiary mc mials which in more modern times occupy
their place.
Perhaps the most extraordinary of all the Mesozoic modifi-
cations of the reptilian type was that of the Hying reptiles, or
^ Anomodontia and Thcriodontia.
170
THE CHAIN OF LIFE.
I'lr,. 144. — An Anomodont Reptile of the Trias (^Di<y»0(/i»t
laccrtkeps, Owen). Reduced.
Fir,. 145. — A Theriodont Rei)tileof the Trias (Z._j'r<Jjfl!wr/«).
— After Owen. Reduced.
Fig. 146. — Skeleton of Pterodochyhis crassirostris.
Jurassic of Solenhofen. Reduced.
THE EMPIRE OF THE GREAT REPTILES.
171
Pterodactyls. These were, in short, li/aids modified for fliglit,
somewhat in the same manner witli the bats among the mam-
mals. If the bat may be likened to a flying shrew-mouse, a
Pterodactyl may in like manner be compared to a tlying lizard;
but the modification in the latter case is by much the more
remarkable, inasmuch as the lizard is a cold-blooded animal,
and far less likely to be endowed with the active circulation
and muscular power necessary to flight than is the mouse. In
point of fact, there can be no doubt that the Pterodactyls must
have been provided with some approach to a mammalian or
ornithic heart, as they certainly were with great breast-muscles
Fig. 147. — Restoration of Rhamphorliyiicus Ihicklandi. Jurassic of England. — After
Phillips.
a, One of the teeth. Natural siie.
attached to a keel in the breast-bone for working their large
membranous wings. These wings were also somewhat original
in their construction. They were not furnished with pinions,
like those of the bird, but with a membrane like that of the
bat, and this, instead of being stretched over four enormously
lengthened fingers, as in that quadruped, was supported on a
single elongated finger, corresponding, singularly enough, to
the little finger, which usually inconspicuous member consti-
tuted in some of these strange creatures a limb longer than the
whole body (Figs. 146, 147). The other fingers of the hand
were left free for walking or grasping. They are thus believed
to have been able to walk as well as to fly, and even in case of
^>.
■,%,
\1
r ^b. ^
IMAGE EVALUATION
TEST TARGET (MT-3)
1.0
I.I
■SO
^ us,
2.0
1.8
1.25
U ill 1.6
172
THE CHAIN OF LIFE.
need, to swim ; while they could probably perch like birds on
rocks and trees, Their heads, though very lightly framed, were
large and reptilian in aspect, and furnished with sharp teeth,
and sometimes probably with a beak as well. Few creatures
of the old world are of more hideous and sinister aspect.
There are many species, most of them small, but some of
those in the later Mesozoic attained to so great a size that
the expanse of their wings must have exceeded twenty feet,
making them veritable flying dragons, probably formidable to
all the smaller animals of their time. Though these animals
Fig. 148. — A Jurassic Bird {/irchaopteryx macroura). — After Owen.
were strictly reptiles, they combined in their structures contri-
vances for aerial locomotion now distributed between the bp.ts
and the birds. They had bat-like wings and bird-like chests.
Some had horny beaks. All had hollow limb bones, and air
cavities to give lightness to the skull. Their brains approach
to those of birds, and, as already stated, their respiration and
circulation must have been of a high order. These facts are
very suggestive, and perhaps in no point is tl.e imagination or
the faith of the devout evolutionist more severely tested than
in realising the spontaneous assumption of these characters by
THE EMPIRE OF THE GREAT REPTILES. 173
reptiles, and their subsequent distribution between the very
dissimilar types in which they are now continued.
The approximation of the winged reptiles to the birds is
urther increased by the facts that in the Jurassic and Creta-
ceous periods there were birds having reptilian tails and
probably toothed jaws {Archaopieryx macroura, Fig. 148).
The species just named, while in its limbs, trunk, and feathers
a veritable perching bird, resembles a reptile in its head and
tail. In the Cretaceous of Western America, Marsh has re-
cently discovered two distinct types of toothed birds, one
having the teeth in regular sockets, the other having them
implanted in a groove in the jaw. One of these birds
nAMd fil^LuLAii
Fir,. 149.— Jaw of a Crttaceous Tocthed Bird (Ichthyomis th's/-ar).—Ahtr Marsh.
Natural size.
{Ichthyornis dispai', Fig. 149) was as large >as a pigeon, with
powerful wings constructed like those of ordinary birds. It
had also the curious and old-fashioned peculiarity of bicon-
cave vertebrae, like those of fishes and some reptiles. Another
{Hesperornis regalis) stood five or six feet high, and had rudi-
mentary wings like those of the Penguins. These toothed
birds extend into the Eocene Tertiary, where the Odontopteryx
of Owen has been known for some time. In the Eocene,
however, this toothed bird is associated with others of ordinary
types, allied closely to the Ostriches, the Pelicans, the Ibis, the
Woodpeckers, the Hawks, the Owls, the Vultures, and the ordi-
nary perching birds. In the Later Mesozoic, indeed, some
reptiles became so bird-like that they nearly approached the
earliest birds ; but this was a final and futile effort of the
reptile to obtain in the air that supremacy which it had long
174
THE CHAIN OF LIFE.
enjoyed in earth and water ; and its failure was immediately
succeeded in the Eocene by the appearance of a cloud of
true birds, representing all the existing orders of the class.
We may close our notice of the winged reptiles of the Meso-
zoic by quoting from Phillips his summary of the characters of
Rhaidphorhyticus (Fig. 147) i :— " Gifted with ample means of
flight, able at least to perch on rocks and scuffle along the
shore, perhaps competent to dive, though not so well as a
palmiped bird, many fishes must have yielded to the cruel
beak and sharp teeth of the Rhamphorhyncus. If we ask to
Fig. 150.— Jaw of Bathygnathus ^'rm/w (Leidy). A Triassic Dinosaur from Prince
Edward Island.
a. Cross section of second tooth, natural size, b. Fifth tooth, natural size.
which of the many families of birds the analogy of structure
and probable way of life would lead us to assimilate Rham-
phorhyncus, the answer must point to the swimming races, with
long wings, clawed feet, hooked beak, and habits of violence
and voracity ; and for preference, the shortness of the legs and
other circumstances may be held to claim for the Stonesfield
fossil a more than fanciful similitude to the groups of Cormor-
ants and other marine divers which constitute an effective part
of the picturesque army of robbers of the sea."
1 Geology of Oxford, p. 227.
THE EMPIRE OF THE GREAT REPTILES. 175
Lastly, the reptiles, in this age of their imperial sway, cul-
minated in the Dinosaurians, animals far above any modern
Reptilia in the perfection of their organisation, and many of
them of gigantic size. Just as the Pterosaurs filled the place
now occupied by the birds, so the Dinosaurs filled that repre-
sented by the mammals, or rather they took up a place holding
some close relations with boih the birds and the mammals.
Fig. 1^1.— Hadrosaiirtis Fottlkii {Cope). An Herbivorous Dinosaur, 28 feet long.—
After Hawkins's restoration.
There were thus reptilian animals which on the one hand were
the elephants and lions of their time, and on the other bore
a grotesque resemblance to creatures so unlike these as the
Ostriches, in so far as their anatomical structure was concerned ;
while it is evident that their whole organisation places them in
the highest position possible within the reptilim class. Some
176
THE CHAIN OF LIFE.
of them must have been herbivorous, and probably slow in
movement and quiet in nature. Others were carnivorous and
of terrible energy, while furnished with the most destructive
weapons (Figs. 152, 153). Many had the power of erecting
themselves on their hind -feet and walking as bipeds ; and to
adapt them to this end their hinder limbs were very large and
strong, and they had long pillar-like tails, while their fore-
feet were comparatively small, and used perhaps mainly for
prehension (Figs. 151, 154).
The size of some of these creatures was stupendous. The
Fig. 152.— Jaws of Megalosaurus.—Mt&r Phillips. One-tenth natural size.
Badrosaunis of New]QTseyf an Herbivorous species (Fig. 151),
when erected on its hind limbs and tail, must have stood more
than twenty feet in height. Megalosaurus and Igtmnodon, of the
English Jurassic and Wealden, must have been of still more
gigantic size. The former was a carnivorous animal, its head
(Fig. 152) four or five feet in length, armed with teeth, sabre-
shaped, sharp and crenate on the edges (Fig. 153), its hind
limbs of enormous power, so that if our imagination does not
fail US in the attempt to realise such a wonder, we may even
THE EMPIRE OF THE GREAT REPTILES. 177
suppose this huge animal, much larger than the largest ele-
phant, springing like a tiger en its prey, a miracle of terrible
strength and ferocit)^ before which no living thing could stand.
Its companion, Iguanodon, was, on the contrary, a harmless
herbivorous creature, using its great strength and stature as
a means of obtaining leaves and fruits for food, and perhaps
falling a prey to the larger Carnivorous Dinosaurs its contem-
poraries. A still more bulky animal was the Ceteosaurus, so
r') J'" •
\i\
Fig. 153.— Tooth of Mcgabsaurus. Natural size
«*, Cross section, b, Crenellation of edges. Enlarged
admirably described by Phillips. Its thigh-bone measures
more than five feet in length and a foot in diameter; and it
must have stood ten feet high when on all fours, while its
length must have reached forty or fifty feet. It seems from
the forms of its bones to have been able to walk on land, but
probably spent most of its time in the water, where it may be
compared to a huge reptilian hippopotamus. Very recently
some bones found in rocks, possibly of Wealden age, in
178 THE CHAIN OF LIFE.
Western America, and described by Cope and by Marsh,
indicate that even Ceteosaurtis had. not attained to the maxi-
mum of Dinosaurian dimensions. These new animals have
vertebrae twenty inches in length and from twelve inches to
. thirteen inches in the diameter of their bodies, while their
lateral processes stretched three and a half feet. The shoulder-
blade of one species is five feet in length, and its thigh bone
• is six feet long. From these measurements Cope concludes
that, unlike most other Dinosaurs, it had the fore-feet larger
in proportion than the hind-feet, so as to have somewhat the
appearance of a large giraffe. The bones of the back have a
remarkable cavernous structure, which Cope interprets as indi-
cating air cavities, to give lightness, as in the case of the bones
of birds ; but Owen suggests that the cavities were filled
with cartilage, and that the animals were aquatic in their
habits. Evidently in point of size the Dinosaurs had a better
claim than even Behemoth to be called the " chief of the
ways of God." Some of them, however, were of small size,
and probably active and bird-like in their movements. One of
these is the animal represented in Fig. 154, a species from the
lithographic limestone of Solenhofen.^
Nothing in the life of the Mesozoic has so seized on the imagi-
nation of evolutionists as the links of connection between birds
and reptiles, which has even been introduced by Huxley into
the classification of animals, by his grouping these heretofore
very distinct classes in one gigantic and comprehensive class
of Sauropsida, It is necessary, therefore, to glance at these
connections, and if possible to arrive at some conception of
their true value. The links which connect the reptiles and the
birds are twofold. First, that between the Dinosaurs and the
ostrich tribe,2 and, secondly, that between the Pterodactyls and
^ Cope has proposed the names Camerosaurus , Amphiaclius, etc., for
these problematical animal?. Marsh names them Titanosaurus, Ailanto-
%aurus, etc., while Owen holds that some of them at least are identical
with his genus Chondrosteosaw iis. Seeley and Hulke adopt the name
Ornithopsis, and support Cope's view of their nature. '^ RatitcB.
THE EMPIRE OF THE GREAT REPTILES. 179
their allies, and the peculiar Mesozoic birds, such as Arc/uc-
opteryx. The first would serve to account for the few excep-
tional Struthious birds of the modern world. The second
would account for the Passerine and other more ordinary birds ;
and thus, according to evolution, the now somewhat homo-
geneous class of birds would have a double, or more probably
multiple, origin from several lines of reptilian ancestors. This,
no doubt, greatly complicates the links of connection, whether
these be supposed to indicate derivation or not.
Fig. \^A,.—Compspgnathus. One of the smaller Dinosaurs. -A*"ter \V;
arner.
If we inquire as to the first connection above stated, we
may define it briefly in the words of Prof. Phillips, with
reference to Megalosaunts, which ''was not a ground-crawler,
like the alligator, but moving with free steps, chiefly, if not
solely, on the hind limbs, and claiming a curious analogy, if
not some degree of affinity, with the ostrich." 1 But the
1 Woodward in a recent paper refers to a still more curious resemblance
of the Dinosaurs to the biped lizard of Australia {Chlatnydosaurus), which
runs on its hind limbi--, and even perches on trees.
N 2
l8o THE CHAIN OF LIFE.
question arises, was this resemblance merely that of two
oviparous bipeds, or anything more? and when we set off
against the resemblance in haunch bones and hind limbs, the
entire dissimilarity in head, in fore limbs, in vertebrae, in tail,
and probably in external covering, we are disposed to agree
with Huxley in his statement, with respect to the Struthious
birds, that their " total amount of approximation to the reptilian
type is but small ; and the gap between reptiles and birds is
but very slightly narrowed by their existence." There is
therefore here a great gap, even in the linking together of the
types, independently of any question of derivation.
The second line of connection appears at first sight more
promising. Archseopteryx has a reptilian tail, and claws on
the wing ; and, if it had toothed jaws, like some of the birds in
the Cretaceous, must have altogether made a much nearer
approach to a reptile than any modern bird does. The re-
markable "fish-bird" (Ichthyornis) of Marsh is also very
reptilian in some of its characters. But when we compare
these reptilian birds with the Pterodactyls and their allies, a
vast gap at once becomes apparent. Disregarding the ex-
ternal clothing, we find the wing in the two groups entirely
dissimilar in details of construction, and this dissimilarity
extends to the hind limbs as well, so that the locomotive
organs resemble those of bats rather than those of birds.
Without committing ourselves to any doctrine of develop-
ment, we might have rejoiced if our geological discoveries had
established a continuous chain, or two continuous chains, of
being between the reptiles and the birds ; but this end is evi-
dently still far from being attained, though some approximation
has undoubtedly been made. To quote again the admission
of Huxley : " Birds are no more modified reptiles than reptiles
are modified birds, the reptilian and ornithic types being both
in reality somewhat different superstructures, raised upon one
and the same ground-plan" — that ground-plan being the
idea of the air-breathing oviparous vertebrate, and the reptile
THE EMPIRE OF THE GREAT REPTILES. iSi
representing the less specialised and less ornate building.
As yet the origin of that idea, and the mode of carrying it
out to completion, remain unknown, except to the Architect
and Builder, who may reveal them to earnest seekers for truth
in His own good time.
As to Imks of connection with the Mammalia, these are still
more obscure. In the Mesozoic the mammals are represented
as yet only by a few small species allied to the pouched
quadrupeds (Marsupials) of Australia, and these are closely
linked with some of the smaller carnivorous Mammalia of the
early Tertiary ; but neither approach very closely to any known
reptilian types. Nor have we yet any connecting links between
the great marine reptiles and the Cetaceans and Sirenians
which in the Tertiary take their place in the sea.
It is an interesting fact, to come before us in our next
chapter, that the great land reptiles of the Mesozoic survived
long enough to become contemporary with the introduction
and first luxuriance of the modern types of vegetation in the
later Cretaceous. It would be natural to suppose that acres"'*
to these grea* supplies of better food .vould have stimulated
the increase and development of the herbivorous species, and
would have indirectly had the same effect on those that were
carnivorous ; but the opposite result seems to have followed,
and in the next period the reptiles altogether gave place to the
mammals, unless, indeed, they were themselves by some
mysterious and comparatively rapid process transformed into
Mammalia, to suit them to the better conditions of an improved
world.
So far as yet known, the reign of reptiles was world-wide in
its time ; and the imagination is taxed to conceive of a state of
things in which the seas swarmed with great reptiles on every
coast, when the land was trodden by colossal reptilian bipeds
and quadrupeds, in comparison with some of which our
elephants are pigmies, and when the air was filled with the
grotesque and formidable Pterodactyls. Yet this is no fancy
i82 THE CHAIN OF LIFE.
picture. It represents a time which actually existed, when
that comparatively low, brutal, and insensate type of existence
represented by the modern crocodiles and alligators was
supreme in the world. The duration of these creatures was
long, and in watching the progress of creation, they would have
seemed the permanent inhabitants of the earth. Yet all have
perished, and their modern successors, except a few large
species existing in the warmer climates, have become subject
to the more recently introduced Mammalia.
How did the ancient reptile aristocracy perish? We are
ignorant of the details of the catastrophe, but their final dis-
appearance and replacement by the more modern fauna was
connected with a great continental suosidence in the Creta-
ceous age, and with changes of climate and conditions pre-
ceding and subsequent to it. Yet the struggle for continued
dominion was hard and protracted ; and toward its close some
of the champions of the reign of reptiles were the greatest
and most magnificent examples of the type ; as if they had
risen in their might to defy approaching ruin. Thus some of
the most stupendous forms appear in the later Cretaceous
after the great subsidence had made progress and almost at-
tained its consummation. Like the antediluvian giants, chey
were undismayed even when the land began to sink beneath
their feet ; and for them there was no ark of deliverance.
Lower Cretaceous Leaves. Reduced in size— After I,esqueretix.
A, AraliaSaportaria. I), Sassafras araliopsis. c, Quercus primordialis,
d, Fagus polyclada. e, Salix proteajolia. f, Laurus protea/olia.
CHAPTER Vlir.
THE FIRST FORESTS OF MODERN TYPE.
FOR a long time it was believed by geologists that a great
and mysterious gap separated the Upper Cretaceous
from the oldest Tertiary formations ; and in Western Europe, in
so far as physical conditions and animal life are concerned, the
severance seemed nearly complete. Oceanic deposits, like the
Upper Chalk, are succeeded by beds of littoral and estuarine
characters. The last and some of the greatest of the Me-
sozoic Saurians have their burial-places in the Upper Cre-
taceous, and appear no more on earth. The wonderful
shell-fishes of the Ammonite group, and the cuttle-fishes of
the Belemnite type, share the same fate. With the earliest
deposits of the Eocene Tertiary came in multitudes of large
Mammalia heretofore unknown, and the Cetaceans appear
in the sea instead of the great marine lizards ; while shells,
corals, and crustaceans of modern types swarm in the waters.
Thus it is true that a great and apparently somewhat abrupt
change takes place at the close of the Cretaceous, and ter-
minates for ever the reptilian age. Even in regions like
Western America, where physically the later Cretaceous
shades gradually into the earlier Tertiary, so that there have
been doubts as to the limits of these several periods, the
same great change in animal life occurs.
But a link of connection has at length been found in the
history of the vegetable kingdom. The modern flora came
i86 THE CHAIN OF LIFE.
in with its full force in the later Cretaceous, before the end
of the reptilian age, and continued onward to the present
time. Thus the plant takes precedence of the animal, and
the preparation was made for the mammalian life of the
Eocene by the introduction of the modern flora in the Cre-
taceous period. In like manner it is possible that the great
graphite deposits of the Laurentian indicate a vegetation
which preceded the swarming marine life of the Cambrian ;
and it is also probable that the palaeozoic land flora existed
long before the first land animals. Thus the plant, as in
the old Mosaic record, ever appears on the day before the
animal, in each stage of th^ development of the world.
In Chapter iv. we traced the history of the old and rich
vegetation of the Coal period. But this vegetation con-
sisted principally of cryptogams and those lowest phseno-
gams, of the pine and cycad groups, which have naked seeds.
In the modern flora we may arrange the several groups of
plants somewhat naturally, as follows : —
Series /., Cryptogams : —
Class J, Tkallophyies, sea-weeds, lichens, fungi.
„ 2, AnophyteSf mosses, etc.
,, 3, Acrogens, ferns, lycopods, horsetails.
Series //., Ph^enogams : —
Class 4, GymnospermSy pines, cycads, etc.
„ 5, EndogenSf palms, grasses, etc.
,, 6, ExogenSj oaks, maples, etc.
With reference to the history of these groups the record
stands as follows :^Jn the palaeozoic age classes 3 and
4 culminated, and constituted the great mass of the
arboreal vegetation. On entering the Mesozoic, No. 3
THE FIRST FORESTS OF MODERN TYPE. 187
becomes somewhat diminished, but No. 4 continues with
unabated prevalence, so that the Mesozoic has sometimes
been characterised as emphatically the age of Gymnosperms.
With these appear some Endogcns, allied to the modern
Yuccas and Screw pines and Arums. But in the lower
Mesozoic rocks we have no representatives of the broad-
leaved Exogens (Angiosperms), which constitute the great
mass of ordinary forest vegetation ; and it is only in the
Cretaceous that we find them appearing in force, and that
the monotonous vegetation of the older style was replaced
by the more beautiful and varied forms of our modern woods.
In Europe, in the lower part of the Uj^per Cretaceous ot
Bohemia {Cefwma?uan), have been found some leaves which
indicate the beginning of this change. These have been
referred to Caesalpinias or Brasilettos, pod-bearing trees of
India and tropical America, Aralias or Ginsengs, Magnolias,
Laurels, an Ivy, and a peculiar and uncertain genus {Credneria).
With these are noble palms, both of the types with pinnate
and palmate leaves, and trees allied to the Giant Sequoias of
California, and to the Araucarian pines of the southern hemi-
sphere. (See Frontispiece to this Chapter.) These ancient
Cretaceous forests of Eastern Europe are compared by Saporta
with those which now live in the warmer portions of China or
in South America — truly a marvellous change from the sombre
and uniform vegetation by which they seem to have been im-
mediately preceded. A still further development of modern
vegetation takes place in the next or highest member of
Cretaceous, the Maestricht beds (Senonian), where we find a
crowd of modern types. On this great change Count Saporta
remarks with truth that there seem to have been periods of
pause and of activity in the introduction of plants. The
Jurassic period was one of inactivity; and a new and
vigorous evolution, as he regards it, is introduced in the middle
of the Cretaceous.
This new and grand elevation of the vegetable kingdom in
i83
THE CHAIN OF LIFE.
the Cretaceous age was not local merely. In Moravia, in the
Hartz, in Belgium and France, even in Greenland, the same
great renewing of the face of the earth was in progress. In
America it was proceeding on a grand scale, and seems to
have set in earlier than in Europe.^ In the Dakota group of the
West, one of the lower members of the Cretaceous, and cover-
ir' avast area, a rich angiospermous flora has been discovered
by Hayden, and described by Lesquereux and Newberry,
and beds of coal have been formed from its remains. In
Vancouver's Island in British Columbia, Cretaceous coal
measures occur, comparable in value and in the excellence of
the fuel they afford with those of the true coal formation.
Some of the beds of coal are eight feet in thickness, and the
shales associated with them abound in leaves of exogenous
trees generally similar to those still living in America. In these
beds are also found mineralised trunks, which present under
the microscope th familiar structures of our oaks, birches,
and other modern '^es. Thus all over the northern hemi-
sphere the elevation ot the land out of the waters of the great
Cretaceous subsidence was signalised by a development of
noble and exuberant forest vegetation, of the types still extant.
The following list of families found in the Cretaceous, after
Saporta, will show the botanist how fully our modern Exogens
are represented : — •
GaMOPETALvE.
Apocynacem.
EricacecR,
EbenaceiB.
Myrsinece.
APETALyE.
Myricace(B.
Cupuliferce,
Betulacece.
SalicacecB.
MorecB.
Proteacece.
Lauracece,
POLYPETALiE.
Aj-aliacece.
Hamameliacece.
Helleborinece.
MagnoliacecB.
Tiliacece.
Celastracea.
Anacardiacea.
Myrtacece.
^ A poplar is .said to occur in Greenland, in beds held to be Lower
Cretaceous.
THE FIRST FORESTS OF MODERN TYPE. 1S9
Of the plants in this list, some, like the oaks, birches, willows,
and heaths, are common and familiar members of the tiora of
the northern hemisphere to-day, and even of the European
flora. Some, like the Magnolias, Myricas, and witch-hazels, are
characteristically American, and a few, like the Proteacese, are
now confined to the southern hemisphere. Some of these
families have dwindled since the Cretaceous time, so as to be
represented by very few species, or at least have not advanced,
while others have multiplied and prospered ; and on the whole
the flora of the northern hemisphere seems to have been as
rich in this early beginning of our modern forests as it is at
the present day. Lesquereux's results, with reference to the
American flora of the Dakota group, are very similar, and
present some surprising features of resemblance to modern
American forests, though he remarks that these Cretaceous
trees are generally characterised by the even or unserrated
edges of their leaves ; and the same remark seems to apply to
the oldest Cretaceous leaves of Europe.
A very singular feature of the Cretaceous flora is the number
of species of some genera now represented by few or even a
single species; and this is the more remarkable when we
consider how few species, comparatively, of the older flora, are
known to us. For example, Lesquereux, though aware of the
great variability of the modem Sassafras of America, recog-
nises eight species of this genus in the Dakota Cretaceous,
one of which seems to be that still living in America, so that
it has continued unchanged, while the others have perished
(Fig. 155). Thus this genus culminates at once in the
Cretaceous, but continues still in one of its species. Again,
the tulip-tree, Liriodendron^ one of the most beautiful, unique,
and invariable of American trees, is represented by one sole
species in the present world. There seem to be no less than
four in the Dakota beds, and one species is found in the
Tertiary of Greenland as well as in that of Europe (Fig. 156).
There are probably four or five species of plane-tree {Piatanus)
190
THE CHAIN OF LIFE.
now extant, ot, which but one occurs in America, unless
P. Mexicana, the Mexican plane-tree, is a good species as
distinct from the ordinary, more northern, form. There are
seven species, according to Lesquereux, in the Cretaceous o''
Dakota alone. This sort of evolution backw. rd, or from
many species to few, would probablv be greatly increased,
.^v
Fig. \i^.— Sassafras cretaceiimi^^^htxty).
had we more full knowledge of the Cretaceous flora, as there
are several genera already represented by as many species as
they can boast in modern times. We have already seen that
this abrupt and sudden culmination of genera and families, and
their subsequent decadence, is no rare thing in geology, and it
connects itself with that idea of periods of creative activity
which we have already had occasion to notice.
THE FIRST FORESTS OF MODERN TYPE. 191
I have dwelt principally on the phaenogamous plants of the
Cretaceous, as presenting the most noteworthy and new
Fig. 156.— LinocU')u/ron/n'»t(erirvi (y^evtherry). A Cretaceous Tulip-tree.
features of the time ; but we must not forget that though cryp-
togams were deposed from the high position they held in the
Palaeozoic, they still existed ; and there are more especially
Fig. 157. — Onoclea sensibilis. Eocene. — ^After Newberry.
many interesting species of ferns and c iiisetums in the Cre-
taceous and Eocene rocks. ThesQ are, however, of modern
192
THE CHAIN OF LIFE.
types ; and it is re.narkable that some of them appea** to have
continued without even specific change from tlie later Cre-
taceous up to the present time. A striking illustration of this
is afforded by two ferns d'scover^d side by side id the oldest
Eocene beds i of the plains west of Red River, and described
in Dr. G. M. Dawson's report on the 49th parallel. Oni
of these is the well-known and very common Onoclea
s'-nsibilis (Fig. 157), or sensitive fjrn of Eastern America. -
Fig. it^.—Dinallia tenui/olia. Eocene.— After Dawson. Natural siie and enlarged
This species came into existence at latest at the close of the
Cretaceous, and has apparently been continued in America up
to the present time. In Europe, where it does not now live,
it occurs as a fossil in Miocene beds in the IbiC of Mull. The
other is Davallia tenuifolia (Fig. 158), a delicate little plant
belonging to a genus not now represented in America, and to
a species at present found only in Asia. Yet this species also
^ By some regarf"ed as Upper Cretaceous.
2 First recognised in American Eocene by Newberry.
THE FIRST FORESTS OF MODERN TYPE. 193
lived in America in early Eocene times, but has since been
banished, thour^h it? former companion, the Onoclea, still
holds its ground. Such cases of specific persistence along
with great changes of habitat are very instruct! /e as to the
permanence of species.
Count Saporta, whose just remarks on the marvellously
sudden incoming of the Cretaceous flora we have already
referred to, also notices the fact that the families and genera
represented in this flora are a most miscellaneous and uncon-
nected assemblage, showing either the simultaneous appearance
of many dissimilar types, or requiring us to believe in the
existence of these and of intermediate forms for a very long
period before that in which they are first found. This inay,
however, be placed in connection with the appearance of
an exogenous tree {Syringoxyion) in the Devonian, referred
to in a previous chapter. It would be a strange and now little
suspected case of imperfection of the record, if it should be
found that trees of this type were lurking in exceptional
corners through all the vast periods between ilie Devonian
and the Cretaceous, to burst forth in unwonted variety and
luxuriance in the latter period.
The new Cretaceous flora appears first in beds which had
been recently elevated from the ocean of the great Cretaceous
subsidence ; and when it first flourished, in temperate regions at
least, the continents were of small dimensions, and broken up
into groups of islands. Farther, America would seem to have
had precedence of the Eastern Continent, and the Arctic of
the Temperate regions. Thus on the elevation of the later
Cretaceous land, plants previously established in the far north
spread themselves southward, over newly-raised lands, radiating
Tiom the polar regions into Europe, Asia, and America. This
seems the only way of accounting for the similarity of the
plants in these distant countries. The new flora of the Upper
Cretaceous in its journey southward met with a climate probably
warmer than the present, yet not so warm as to prevent trees
o
THE CHAIN OY LIFE.
ILilar to those now Uving in the same latitudes from
"tSow trace this flora ,hro„sH the -cee^ng ages j^^
„hich I shall follow pretty closely some g^^b"
™ade by Count l)e Saporta in --""'-/^^^^''^d trm
At the beirinnin<r of the Eocene we find a humid ana wa
dim tttn Slperwith great forests of oaUs, che-ut. aurd •
giant pines, and other genera some of the^n ^^^^
others Asiatic or American, and many of them survivor
Fig i59.-Eoeene Leaves. From Aix.
cretaceous (Figs r5,to;6.). and at^^
ni\v~:: from ut r Creteous sea, and there vast
TbTdl of brown coTsome of them eighteen feet in thick-
Tteri came in kurope and Asia that great subsidence
" . ■ t?e seaXing whic, the Nummuline limestones were
under the ^^^''^^^^^ ^^^.^^^^^ ^^^ ^^^„,,,d
irl 'a^htCof islands, perhaps closely connected
THE FIRST FORESTS OF MODERN TYPE. 195
with more southern lands. This led to a great increase
of southern forms of plants, which does not seem to have
occurred to the same extent in America, where the flora
Kin. :6o.— An Ancient Clover [Tri/oUum
talteogtenm, Saporta). Eocene. Aix.
Fig. i6r.— An Eocene Maple {Acer sex.
tianus, Saporta). Aix.
Fig. 162.— a European Magnolia of the
Eocene (/W. diantf, Saporta). Aix.
is more continuous, though showing a warmer climate in the
older than in the newer Eocene. At this period Palms, Screw-
pines, Proteaceous shrubs, Myrtles, Acacias, and other plants
o 2
19^
THE CHAIN OF LIFE.
of the character of those of more southern climates were
dominant in Europe (Fig. 163). ^he well-known beds of
Bournemouth, in the south of England,* contam a rich flora
of the Eocene age, perhaps of its middle period, and remmdmg
us of the forests of sub-tropical India or Australia.
' Gradual elevation of th'i land favoured for a time the
extension of these plants, and the warmth of the chmate
F,G. i63.-Flower and Leaf of Bombax .epultijlorum. Eocene of Aix.-After Sapcr.a
A European representative of the Silk-cotton-tree of the East Indies and
* Tropical America.
allowed them to extend even into Arctic latitudes. But at
the close of tie Eocene another subsidence occurred, which
exterminated much of the Eocene flora, and was perhaps
accompanied with a reduction of temperature, m which the
more northern lands became covered with great forests of
trees allied to the Pines. In the Miocene period the land
1 Described by La Harpe and Gaudin, and recently by Gardner.
THE FIRST FORESTS OF MODERN TYPE. 197
again rose, and tlie northern flora spread itself southward
equally over Europe, Asia, ? d America, so that the Miocene
flora of all these regions is very similar; and this Miocene
flora continues substantially to this day in Eastern America
and Eastern Asia, except that it has been greatly reduced in
number of species by the intervention of the cold glacial
period ; but in Europe and in Western America it has been
largely replaced by other and apparently more modern species.
In England a remarkable deposit of this age is that of Bovey
Fig. 164. — Branch and Fruh'of Seguoia Coiiiisice {llecr). Miocene. England.
Tracey, in Devonshire, where beds of clay and brown coal
have afforded a rich flora of American and southern types.
The Sequoia shown in Fig. 164 abounds at this place, and is a
near relation of the celebrated *' big trees " of California ; the
Cinnainomum in Fig. 165 is a type equally foreign from
modern England. It is a curious feature of the Bovey deposit
that immediately above these Miocene beds, holding a rich
flora of warm temperate character, are glacial clays with leaves
of Arctic willows and of the dwarf birch, indicating a
198 THE CHAIN OF LIFE.
climate much more severe than that of the British Islands at
present.
A striking result of recent discoveries is the fact that in
Cretaceous and Miocene times, and probably also in the inter-
vening Eocene, a very warm climate prevailed in the extreme
Arctic regions, and trees of temperate latitudes grew there
Fig. x6S'—Cittnamomum Schenchzeri (Heer). Miocene. England.
freely. In the recent Arctic expedition, Captain Fielden
found in latitude 8i° 40', within 600 miles of the Pole, a bed
of lignite from twenty-five to thirty feet in thickness, asso-
ciated with remains of plants such as now grow only in
temperate latitudes.
" From the character of the plant-remains, Dr. Heer infers
THE FIRST FORESTS OF MODERN TYPE. 199
that the lignite of this locality represents an ancient peat-moss,
which must have been of wide extent, with reeds, sedges,
birches, poplar, and certain conifers growing on its banks ;
while the higher and drier ground in the neighbourhood
probably supported a growth of pines and firs, with elms and
hazel-bushes. The remains of water-lilies suggest the existence
of a fresh-water lake in the old peat-moss, which must have
remained unfrozen during a great part of the year."
It is to be observed, with reference to the Miocene age of
these beds, that as the Miocene flora of Europe and America
migrated from the north, the plants found in the beds of that
age in the temperate latitudes may really be Eocene in the
Arctic regions, a fact which produces some uncertainty as to
their actual age ; and even in temperate America there is
reason to believe that a flora which in Europe might be called
Miocene existed in Eocene times, and extended with com-
paratively little change thiough the Miocene into the Pliocene
period.
The warmth required for the growth of luxuriant forests
near vhe Pole might be secured by a different distribution of
land and water, and of the oceanic currents, but the require-
ments of plants as to light seem more difficult to meet, and it
has been doubted whether species similar to those which
are accustomed in modern times to regular alternations of day
and night could submit to the long Arctic winter darkness.
It is known, however, that in conservatories in Northern Russia
plants supplLJ with heat and moisture can endure in winter
great deprivation of light, and at Disco, in Greenland, roses
and fuchsias flourish as house plants.^ These facts show that
if there were sufficient light and heat in summer, . great
number of tlic plants of temperate latitudes could endure
extreme cold and much deprivation of light in winter.
It may be well here to inform the render that some confusion
as to the succession of the Cretaceous and Tertiary floras in
^ Lyell, Principles ; Brown, Florula Diicoana,
200 THE CHAIN OF LIFE.
America has arisen from the fact that the plants which are
Eocene in Greenland and America are Miocene in Europe.
The statement of this places the reader somewhat behind the
scenes, for the fact is .ot icnown to some who are regarded as
high authorities in this matter. In the Western States, the
Da'.vota group of Lesquereux is overlaid by 2000 feet of
Cretaceous beds, containing the marine shells characteristic of
that age, but no plants. But in Vancouver's Island these same
Upper Cretaceous beds contain an abundant flora, which
some botanists persist in calling Tertiary for reasons to
be mentioned in the sequel. Above the 2000 feet of marine
beds overlying the Dakota group is the Lower Lignite group of
Lesquereux, holding many fossil plants, including Palms and
other evidences of a warmer climate than that of the CretaceouL,
and which constitute a Lower Eocene flora correspondir ■'
some respects to that of Europe. This is succeeded by an
Upper Lignite group, also Eocene, but representing a more
temperate climate, and therefore resembling more nearly the
Cretaceous flora. This is nearly identical with the so-called
Miocene of Greenland, Alaska, and McKenzie River, which
the facts collected by the Canadian geologists have shown to
be really Eocene.^ But the Canadian reports containing
these facts are comparatively little known in Europe, hence
incorrect ideas as to the succession of these floras have been
handed from one writer to another.
To those who adopt extreme views as to the refrigeration of
the northern hemisphere in so-called glacial times, there is
great difficulty in accounting for the continued existence of
the early Tertiary flora ; but if we adopt moderate views as
to this, and demand merely a great subsidence, with much
reduction of mean temperature, we may suppose that the
plants previously existing were preserved on insular spots,
whence they were ready to recolonise the land on its emergence
from the sea. It seems certain, however, that our continents
1 G. M. Dawson, Report on \<^th Paralld ; Report on British Co'.iimbia.
THE FIRST FORESTS OF MODERN TYPE. 201
never regained, after the Glacial period, the exuberancvi of
plant life which they presented in the Miocene and earlier
Pliocene ; and we shall find that this statement applies to the
world of animals as well as to that of plants. This reduction
was more extreme in Europe than in Eastern Asia and Eastern
America, and the fact is thus accounted for in a recent lecture
by Prof. Asa Gray : —
" I conceive that three things have conspired to this loss.
First, Europe, hardly extending south of latitude 40°, is all
within the limits generally assigned to severe glacial action.
Second, its mountains trend east and west, from the Pyrenees
to the Carpathians and the Caucasus beyond, near its southern
border ; and they had glaciers of their own, which must have
begun t^ '^ir operations, and poured down the northward flanks,
while the plains were still covered with forest, on the retreat from
the great ice-wave coming from the north. Attacked both on
front and rear, much of the forest must have perished then and
there. Third, across the line of retreat of those which may
have flanked the mountain-ranges, or were stationed south of
them, stretched the Mediterranean, an impassable barrier. Some
hardy trees may have eked out their existence on the northern
shore of the Mediterranean and the Atlantic coast. But we
doubt not, Taxodium and Sequoias, Magnolias and Liquidam-
bars, and even Hickories and the like, were among the missing.
Escape by the east, and rehabilitation from that quarter until a
very late period, were apparently prevented by the prolongation
of the Mediterranean to the Caspian, and thence to the Siberian
ocean. If we accept the supposition of Nordenskiold, that
anterior to the Glacial period, Europe was 'bounded on the
south by an ocean extending from the Atlantic over the present
deserts of Sahara and Central Asia to the Pacific,' rJl chance
of these American types having escaped from or re-entered
Europe from the south and east, is excluded. Europe may
thus be conceived to have been for a time somewhat in the
condition in which Greenland is now, and indeed to have been
202 THE CHAIN OF LIFE.
connected with Greenland in this or in earlier times.* Such a
junction, cutting off access of the Gulf Stream to the Polar Sea,
would, as some think, other things remaining as they are,
almost of itself give glaciation to Europe. Greenland may be
referred to, by way of comparison, as a country which, having
undergone extreme glaciation, bears the marks of it in the
extreme poverty of its flora, and in the absence of the plants
to which its southern portion, extending six degrees below the
Arctic Circle, might be entitled. It ought to have trees, and
might support them. But since destruction by glaciation no
way has been open for their return. Europe fared much better,
but suffered in its degree in a similar way.
"Turning for a moment to the American continent for a con-
trast, we find the land unbroken and open down to the tropic,
and the mountains running north and south. The trees, when
touched on the north by the on coming refrigeration, had only
to move their southern border southward, along an open way,
as far as the exigency required ; and there was no impediment
to their due return. Then the more southern latitude of the
United States gave great advantage over Europe. On the
Atlantic border, proper glaciation was felt only in the northern
part, down to about latitude 40°. In the interior of the country,
owing doubtless to greater dryness and summer heat, the limit
receded greatly northward in the Mississippi Valley, and gave
only local glaciers to the Rocky Mountains ; and no volcanic
outbreaks or violent changes of any kind have here occurred
since the types of our present vegetation came to the land. So
our lines have been cast in pleasant places, and the goodly
heritage of forest-trees is one of the consequences.
"The still greater richness of North-east Asia in arboreal vege-
tation may find explanation in the prevalence of particularly
favourable conditions, both ante-glacial and recent. The trees
* Gray's reasoning is based on the extreme view of the Glacial period
now prevalent in America, contrary, as it appears to me, to the actual facts ;
but with limitations it holds good on more moderate views as well.
THE FIRST FORESTS OF MODERN TYPE. 203
of the Miocene circumpolar forest appear to have found there a
secure home ; and the Japanese islands, to which most of these
trees belong, must be remarkably adapted to them. The situa-
tion of these islands — analogous to that of Great Britain, but
with the advantage of lower latitude and greater sunshine —
their ample extent north and south, their diversified configura-
tion, their proximity to the great Pacific gulf-stream, by which
a vast body of warm water sweeps along their accentuated
shores, and the comparatively equable diffusion of rain through-
out the year, all probably conspire to the preservation and
development of an originally ample inheritance."
The comparative paucity in species of the west coast of
America, though the Sequoias and some other forms which
have perished elsewhere are retained there, is admitted to be
exceptional, and not easily explained, except by the supposi-
tion of peculiar local conditions affecting the comparatively
narrow strip ot land between the Rocky Mountains and coast
ranges, and the Pacific.
To such widely-distributed and varied and complex pheno-
mena as those which have been discussed in the present
chapter, it is impossible to do justice in the space at our
command. Details in relation to them will be found in the
publications of Heer, of Saporta, and of Lesquereux, and are
well worthy of study by botanists, to whom alone they can be
made fully intelligible. In general, with reference to now
prevalent theories of derivation, they present two very dissimilar
aspects. No difficulty can be greater to the evolutionist than
to account for the simultaneous appearance of so many
modern generic forms in the Cretaceous; and le fact of
many of the genera presenting more and more species the
farther we trace them back is a strange anomaly of evolution.
On the other hand, the number of species continuing un-
changed from the Eocene to the Modern, the others only
slightly modified, and the representative species occurring in
the floras of the old and new continents, appear to many to
204 THE CHAIN OF LIFE.
give great support to the doctrine of gradual transformation of
species. Farther facts and farther comprehension of the dif-
ference between species and races will be necessary to the
settlement of these questions. In the meantime it would
appear that the Jurassic flora rapidly gave place, at a particular
point of geological time, to that of the modern world, and
this not merely in one locality, but over the whole northern
hemisphere ; and there are apparently similar facts in the
southern hemisphere as well. It farther appears that each genus
was at first represented by many species, and that as time went
on these were gradually reduced to a few best suited to
survive ; and that the changes of climate and level which
occurred distributed these over different parts of the con-
tinents in a way at first sight very anomalous, but which Prof.
Gray somewhat quaintly represents as follows : —
" It is as if Nature, when she had enough species of a
genus to go round the four floral regions (Europe, East Asia,
West America, and East America), dealt them fairly one at
least to each quarter of our zone ; but when she had only two
of some peculiar kind, gave one to us, and the other to Japan,
Mantchuria, or the Himalayas ; and when she had only one,
divided it between the two partners on the opposite sides of
the table."
Lastly, it seems very probable that many so-called species
are nothing more than varietal forms, which may very well
be modified descendants of Miocene or Eocene plants now
figuring in our lists under different names.
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CHAPTER IX.
THE REIGN OF MAMMALS.
THE incoming of that highest order of animals in which
man himself, in so far as his physical nature is concerned,
takes his place, presents some features which, though not un-
paralleled in the history of other forms of life, are still very
striking. The modern Mammalia are somewhat sharply divided
into three very unequal groups. First, those which present in
their full perfection the property of producing fully developed
young, which is one of the distinctive characters of t ie class.
These are the Placental Mammals. Secondly, those in which
the young are produced in a very imperfect condition, apd are
usually nourished for a time in a marsupium or pouch. These
are hence called Marsupials. They are for the most part con-
fined to Australasia, though a few occur in America ; and are
decidedly inferior in rank to the ordinary mammals. Thirdly,
those in which there is a bird-like bill, and also certain bird-
like or reptilian peculiarities of skeleton and of the alimentary
canal. These are the Monotremes, represented by a very few
species in Australia and New Guinea.
In geological history, so far as the facts are at present known,
the second group, that of the Marsupials, antedated the others
by a vast lapse of time. The Marsupials appear in the Trias,
near the beginning of the Mesozoic period. The Placentals
2o8 THE CHAIN OF LIFE.
are not found until we reach the beginning of the Tertiary.
The Monotremes would seem to be a comparatively modern
degraded type. Thus the Marsupials existed throughout the
reptilian age, and this in those countries of the northern
hemisphere in which they are not now found. The Mesozoic
Marsupials were, it is true, of small size, but there were
probably numerous species, and though unable to cope with
the great reptiles that swarmed by the shores and on the
plains, they may have found abundant scope in the upland
and interior regions of the continents.
The Upper Trias of Germany has afforded to Professor
Pleininger two teeth of a small mammal, to which the name of
Aficrolestes antiquus has been given, under the impression that
it was carnivorous, though it now seems more likely that it
was a vegetable feeder. In rocks of nearly the same age in
America, Emmons found a jaw-bone of another species {Dro-
viatherium sylvestre), which appears to be a near ally of the ex-
isting Myrmecobius fasciatus of Australia (Figs. i66, 167). In
the Stonesfield slate, a member of the English Jurassic, several
othrr species have been found (Fig. 168), and a still larger
number in the freshwater beds of the Upper Purbeck. None
appear to have yet been found in the Cretaceous, but they re-
appear in the Eocene Tertiary, and continue to the modern
time. Their absence in the Cretaceous is probably a mere
accident, and they present an illustration of a very permanent
type little changed since its first introduction. Lyell enume-
rates in all thirty-three species from the Mesozoic, all of them
of small size, and all more or less nearly related to existing
Australian Marsupials, though differing much among them-
selves, and including both carnivorous and herbivorous forms
(Fig. 169).
So soon as the palaeonlotogist passes from the Upper
Cretaceous to the Eocene, he finds himself in the domain of
the placental mammals, which appear in numerous and large
species, and this, not merely in one region, but in every part
THE REIGN OF MAMMALS.
2oy
of the world in which these deposits are known to exist.
Indeed the recent discoveries in America and in the east of
Europe have almost thrown into the shade those researches of
Cuvier in the Paris basin which first brought this important
fact to light. The Eocene mammals, like the Carboniferous
Via. i66. — Jaw of Dromathct ium y/z/fj^/*^ (Emmons). From the Trias of North Carohna.
amphibians, the Mesozoic reptiles, and the Cretaceous forests,
appear to spring full-grown from the earth, and this at nearly
the same time in every part of the northern hemisphere. It
has been suggested that they may have come in gradually
Fig. 167. — Myrmecobius fasciatus. A modern Australian marsupial, allied to Mesozoic
species.
without our knowledge in the Cretaceous period ; but if so,
we should have found some of their remains along with those
of the Upper Cretaceous plants. But the prevalence of the
great reptiles up to the close of the Cretaceous would seem to
ender the co-existence of large mammals unlikely. It has
p
210
THE CHAIN OF LIFE.
further been supposed that geological changes in the southern
and northern hemispheres may have alternated with each other,
so that there may be in the former Cretaceous beds in which
the remains of ancestors of the Eocene mammals may be
V »^ "
Fig. i68.— Jaw, and enlarged molar of P/tascolot/wn'upn Bucklandi. Stonesfield
slate. England.— After Phillips.
found. But we do not as yet know of such deposits. We
may be content, therefore, to suppose that at the close of the
Cretaceous there was established somewhere a sort of Eden
for the first placental mammals, in which they were introduced
and could live unharmed by the decaying monsters of the
reptilian age, until the time came when they could increase and
Fig. 169. — Plagiaulax Becklesii. Taw, and pre-molar enlarged, showing flat
surface, with ridges. — Purbeck.
multiply and replenish the earth. The nearest approach to
such a centre of mammalian life is perhaps to be found in those
great American lake basins embedded in the mountains of
the West, which have been so well described by Hayden and
THE REIGN OF MAMMALS.
211
Newberry, and which have yielded so many animal remains to
the researches of Leidy, Marsh, and Cope.
The typical deposits of the Early Eocene have long been
those of the Basin of Paris, where thick and highly fossiliferous
deposits of this age rest on the more or less denuded surface
of the Upper Chalk, and have afforded a rich harvest of re-
mains of about fifty species of placental quadrupeds, whose
bones have been found in the gypsum quarries of Montmartre.
The great majority belong to the Ungulates, or hoofed animals,
and the most abundant genera are those called by Cuvier
Fig. 170.— Restoration of Palceotherium magnum. Eocene.— After Cuvier and Owen
PalcBotherium (Fig. 170) and Anoplothenum, of which there
are several species, and which have affinities with the modern
Tapirs on the one hand, and with the Horse on the other. Of
the Unguiculate or clawed orders there are carnivorous forms
allied to the Hyaena and the Fox, a Bat and a Squirrel ; and the
Marsupials are represented by an Opossum. Lyell describes a
bed of clay associated with the gypsum, in which are numerous
footprints, probably produced on the margin of a lake. Many
of these might be referred to the Palaeothere and its allies ;
p 2
212 THE CHAIN OF LIFE.
but there are others belonging to quadrupeds yet unknown,
and there are also tracks of tortoises, crocodiles, and lizards,
and of a large wading bird. Such a bed, perhaps deposited on
the margin of a salt lake, resorted to as a " lick " by herbivorous
animals, and by the carnivorous species which preyed on them,
is well fitted, by the thronging life which it indicates, to teach
how little we can know of the actual number and variety of
the old inhabitants of the earth.
In England, Eocene beds of the age of those of Paris, occupy
the valley of the Thames and the Isle of Wight and neighbour-
ing parts ot Hants. They have afforded mammalian fossils
similar to those of Paris, though less abundantly, but they are
rich in remains of marine animals and of land plants.
Instead of describing the well-known animals of the French
and English Tertiaries, from these Eocene deposits upwards,
I shall shortly sketch the succession in America, as worked
out by Marsh and Cope, with the aid of the admirable summary
given by Gp.udry of the present state of knowledge with refer-
ence to the sequence of mammalian life from its appearance
in the Early Eocene up to the present time.'
Eocene mammals, especially those gigantic whale-like
creatures called Zeuglodon (Fig. i8o), have been found in
Eastern North America, but the most remarkable discoveries
have been made in the Western Territories, where vast numbers
of bones are imbedded in certain ancient and wide-spread
lacustrine beds. It may be well to premise here that though
the division into Eocene, Miocene, and Pliocene is recognised
in America as well as in Europe, the limits of these groups
may not precisely correspond with those in the Old World.
Still we have this certain point of departure, that the Eocene
begins where the peculiar animals of the Cretaceous end, and
that the drying up of the later Cretaceous sea and the esta-
blishment of tlie Eocene land were probably nearly con-
temporaneous in both continents. It is true, however, in
^ Les Enchainements du Monde Animah
THE REIGN OF MAMMALS. 213
animals as in plants, that in the successive periods of the
Tertiary, America presents an older aspect than Europe, just
as its modern fauna still contains such old forms as the
opossum.
It would seem that as the mountain-ranges and table-lands
of Western America emerged from the Cretaceous waters, they
became clothed with Eocene forests and inhabited by Eocene
mammals. But the waters, dammed up by surrounding ridges,
formed large lake basins, which were drained only by the
slow excavation of "canons" as the land rose still higher.
In the successive deposits formed in these lakes both by
ordinary deposition of silt and by paroxysmal showers of
volcanic aslies were entombed great numbers of the animals
which fed on their banks. It appears that these deposits,
which in some places are estimated at not less than 8000
feet in thickness, hold the remains of three successive faunas,
differing materially from each other, and representing the
Lower, Middle, and Upper Eocene. On the flanks of the
elevated region supporting the beds formed in the Eocene
lakes, are other later lake basins of Miocene age, also
abounding in animal remains. East of the Rocky Mountains,
and also on the Pacific coast, are still • later Pliocene deposits
holding other and more modern Mammalia. The vast area
of these formations and the complete sequence which they
show are scarcely equalled elsewhere.
As in the Paris basin, the large Ungulates constitute the most
conspicuous feature. This great group is now usually divided
into those that are odd-toed (Perissodactyl), and those that
are even-toed (Artiodactyl). Though these are apparently
arbitrary characters, they correspond with other more funda-
mental differences. The first includes such modern animals
as the Rhinoceros, Tapir, and Horse. The second includes two
somewhat distinct assemblages — that with mammillated teeth,
of which the Hog and Hippopotamus are types (Bunodonts),
and that with crescental plates of enamel in the teeth, of which
214
THE CHAIN OF LIFE.
the Ruminants like the Deer, Ox and Camel, are examples
(Selenodonts).
The most characteristic animals of the lowest Eocene belong
to the genus Coryphodon (Fig. 171, 172), which so abounded m
Fir 171 -Corypiwdon Hamatus. A Lower Eocene Perissodactyl skull, greatly reduced.
Fig. 171- K^orypnoa ^^^jj ^.^^ ^f train, a.- After Marsh.
Eocene America that bones of about 150 individuals were
found by the Wheeler Expedition in one year in the Eocene
beds of New Mexico. These animals in their dentition
approached the American tapirs, except that they had great
THE REIGN OF MAMMALS. 215
canines like the bear, while their feet resembled those of the
elephant, and some of them attained the dimensions of the
ox. Coryphodon is thus, as might be expected in a primal
placental mammal, a creature of somewhat generalised type.
Another point in which it resembles some at least of its early
Tertiary contemporaries is the small size of the brain, especially
in those parts of it supposed to minister to the intelligence
and higher instincts (Fig. 171, a). It is certainly remarkable
that as Tertiary time went on the successive groups of mammals
were gifted with brains of larger and larger size, fitting them
for higher functions, and ultimately for associating with man.
Fig. ij2.— FoTe-ioot oi Coryp/iotion. Greatly reduced. — After Marsh.
Animals thus low in development of brain were probably slow
and sluggish and stubbornly ferocious, and dependent on brute
force for subsistence and defence ; and they would have been
altogether unsuitable for domestication had they lived to the
present time.
In |:he Middle Eocene, the place of Coryphodon was taken
by Dinoceras and allied forms. Some of the species nearly
equalled the elephant in size, but had shorter and stouter
limbs, each supported on five great toes — the most perfect
possible sort of pedestal foot (Figs. 172, 174). They were
heavily armed with immense canines on the upper jaws, and
two or even three pairs of horns or hard protuberances on the
2l6
THE CHAIN OF LIFE.
head (Fig. 173). Creatures so supported and so armed, and
living where food was plentiful, might well dispense with any
great degree of intelligence, and their development of brain
is consequently little better than that of Coryphodon. These
great and characteristic Eocene families have no known
successors; and in the Miocene age their place is taken by
a very different group, that of which L^ontotherium is the
J''if;. 173. — Skull of an Upper Eocene Perissodaclyl {Dinoceras vtt'rahilis), showing three
pairs of horn-bases. Greatly reduced. — After Alarsh.
type (Fig. 175). They are creatures of huge size, with a pair
of horn-cores on the nose, and feet with four toes in front
and three behind, resembling in form those of the rhinoceros.
While these gigantic Perissodactyles have no successors as
yet known to us, another and less conspicuous Eocene type
can be traced onward to modern times by a chain of successors
wmch the imagination of evolutionists has converted into a
THE REJ^iN OF MAMMALS.
217
veritable genetic series, to which they appeal as a "demon-
stration " of the process of descent with specific modifications.
In the Lower Eocene are found the remains of a diminutive
Fig. 174.— Fore.fojt of Dinoceras. Greatly reduced.— After Marsh.
ungulate {Eohippus), of the stature of a moderately-sized dog.
It has four toes and a rudiment of a fifth in front, and three
Fig. 175.— Skull of Brontotherium ingens (Marsh). Greatly reduced. A Miocene
Perissodactyl.
toes behind ; and has teeth slightly resembling those of the
horse, but more simple and shorter in the crown. In this
creature it has been supposed that we have a direct ancestor
2l8
THE CHAIN OF LIFE.
of the modern horse. A very similar genus {Orohippus)^
lacking only the fifth rudimentary toe, replaces Eohippus in
the Middle Eocene. Mesohippus of the Lower Miocene is as
large as a sheep, and has only three toes on the fore-foot and
a splint bone, while its teeth assume a more equine character
(Fig. 17b). In the Upper Miocene Miohippus continues the
line, while Protohippus of the Lower Pliocene is still more
equine and as large as an ass, and corresponds with the
European Hipparion in having the middle toe of each foot
alone long enough to reach the ground. In the Upper
Pliocene true horses appear with only a single toe, and splint
bones instead of the others. In America, though the horse was
Fig. 176. — Series of Equine Feet.— After Marsh.
a, Orohifipus, Eocene, b, Miohippus, Miocene, c, Protohippus, Lower Pliocene.
d, Pliohippus, Upper Pliocene, e, Equus, Post- Pliocene and Modern.
unknown at the time of the discovery of the continent, several
species occur in the Tertiary and Post-Pliocene, showing that
the genus existed there up to a comparatively late period ; and
when re-introduced it has thriven and run wild in the more
temperate regions. What cause could have led to its extinction
in Post-Glacial times is as yet a mystery. This genealogy of
the horse, independently of its evolutionist application, is very
interesting. It shows that some Eocene types were suited to
continuance, and even adapted for extension, while others were
destined to become altogether extinct at an early date. It
shows farther that the power of continuance resided not so
much in the gigantic and prominent species as in smaller
THE REIGN OF MAMMALS. 219
forms. It is to be observed, however, that Gaudry and other
orthodox evolutionists in Europe deduce the horse, not from
Eohippus, but from Falceotherium^ and that it is equally im-
possible to verify either phylogeny, since the mere sequence
of more or less closely allied species in time does not prove
continuous derivation. Nor indeed are we certain that one-
toed horses like those now living did not exist on the dry
plains in Eocene times, since the inhabitants of these plains
are probably unknown to us. An amusing illustration of the
probable reason of the disappearance of the missing links
has recently been given by a writer not very favourable to
the new philosophy. The several consecutive species may
be represented by coins. We may suppose, for example, six-
pences to have been coined first, then sevenpenny, eightpenny
pieces, and so on up to a shilling, then pieces representing
thirteen, fourteen, and fifteen pence, and so on up to a half-
crown or crown ; but all the intervening denominations between
the sixpence and the shilling, and between the shilling and
the half-crown, were found practically of little use. Hence
few were coined, and they soon became obsolete. Thus the
antiquary would find only a few denominations, and those
connecting them would be seldom or never found. It is
plain that if we could suppose that nations constructed their
coinage after this unthinking and empirical fashion, and that
if we were justified in ascribing a similar procedure to thd
Creator, it might help to account for the facts as we find
them, otherwise we should rather suppose that in both cases
something like plan and calculation determined the selection
of the species produced, whether of coins or animals. But
Chance is a blind goddess, and if we instal her as creator,
we must expect the v/ork to proceed by a series of abortive
experiments.
The Perissodactyls are not numerous at present. The
three groups represented by the Horse, Rhinoceros, and Tapir
constitute the whole ; and the two latter forms can be traced
220 THE CHAIN OF LIFE.
back to predecessors in Eocene times, even more closely re-
sembling them than those supposed to be ancestors of the
horse resemble that animal. But the few species now living
have thus a vast surplusage of possible ancestors. Many
species and genera are dropped without any modern repre-
sentatives, so that the tendency has been to a gradual elimina-
tion of surplus types, until only a few isolated and somewhat
specialised forms remain at present. Yet this process of
elimination is not necessarily an evolution or survival of the
fittest, in the sense of modern derivationists. It rather implies
that in certain past conditions of the earth the conditions of
life afforded scope for many forms not now required, or
replaced by other types more suited to the advanced and
specialised nature of the world.
On the other hand, the Artiodactyls have gained in numbers
and importance, in comparison with their odd-toed comrades ;
and this, though an odd number, namely five, was the typical
number with which the earliest quadrupedal forms began life
far back in the Palaeozoic. The typical Artiodactyls are those
that cleave the hoof, and many of which also chew the cud ;
and they are of all others, the horse perhaps excepted, those
that are most valuable to man. The lower type (Bunodont),
to which the hog belongs, is the older; and many hog-like
animals occur from the earlier Tertiary upwards. In the
Upper Eocene, even-toed species appear with an approach at
least to the crescent-shaped teeth of the modern deer and
oxen. Some of the species are obviously forerunners of the
modern antelopes and deer, though as yet destitute of horns or
antlers. Others, like Oreodon, are of more hog-like aspect,
though believed to have been ruminants (Fig. 177). These
are characteristic of the Middle Miocene, at which stage true
deer appear in Europe (Dicroceras), though they are not known
in America until the Pliocene period. The earliest deer have
small and simple antlers, these ornaments becoming larger
and more elaborate in approaching the modern era. The
THE REIGN OF MAMMALS.
221
hollow-horned ruminants appear for the first time in America
in the Lower Pliocene ; and no ancestry has so far been at-
tempted to be traced for them. The antelopes of this group,
as well as the gigantic Sivatherium of India, ^ allied to the
modern prong-horned antelope of North America, were pro-
minent in the Old World in the Miocane,
A very noteworthy and specially American group of mammals
is that of the Edentates^ the Sloths and Ant-eaters, a group
which h priori wt should hj've supposed would have been one
of the earliest in time. They appear, however, first in the
Miocene, without even any suggested ancestry, and are repre-
sented from the first by large species, though they attain their
Fig. 177. — OreodoK major. A generalised Miocene ruminant, with affinities to the
Deer, Camel, and Hog. Greatly reduced. — After Leidy.
grandest stature in the Megatherium and Mylodon of the Post-
Pliocene (Figs. 178, 179), which were sloths of so gigantic size
that they must have pulled down trees to feed on their leaves,
unless, indeed, there were trees equally colossal for them to
climb. But before the modern time, like the American horses,
the larger herbivorous forms suddenly disappear, and are now
represented only by a few diminutive South American species,
which can scarcely, by any stretch of imagination, be supposed
to be descendants of their gigantic predecessors. The history
of these animals, like those of the great Tertiary marsupials ot
Australia and the many Miocene elephants of India, affords a
1 See Frontispiece to this Chapter,
222 THE CHAIN OF LIFE.
remarkable illustration of the persistence of similar groups of
creatures in successive ages in the same region, along with
diminution in magnitude and number of species toward the
modern times.
Fig. 178, — Lower Jaw of Megatherium, dreatly reduced. Post-Pliocene of South,
America. — After Owen.
The Whale-tribe (Cetaceans) at once in the earliest Eocene
takes the place of the great Sea-lizards of the Cretaceous ; and
the oldest of the whales are in their dentition more perfect
Fig. 179. — Ungual Phalanx and Claw-core of Megatherium. Greatly reduced.
than any of their successors, since their teeth are each implanted
by two roots, and have serrated crowns, like those of the Seals.
The great Eocene whales of the South Atlantic {Zeuglodori)
(Fig. 180), which, have these characters, attained the length of
THE REIGN OF MAMMALS. 223
seventy feet, and are undoubtedly the first of the whales in
rank as well as in time. This is perhaps one of the most
difficult facts to be explained on the theory of evolution.
Allied to the whales is the small and peculiar group of the
Sea-cows or Diigongf (Sirenians). These creatures, highly
specialised and very distinct from all others, appear in the
Early Tertiary in forms very similar to those which now exist,
and probably in much more numerous species, and they pursue
Fig. i8o.-Tooth of Eocene Whale {Ze7,glodon cetioides). One-half natural size.
the even tei. . of their way down to modern times without
perceptible elevation or degradation. " We have questioned,"
says Gaudry, when speakingof the Tertiary Cetaceans, " these
strange and gigantic sovereigns of the Tertiary oceans as to
their progenitors— they leave us without reply." Their silence
is the more significant as one can scarcely suppose t" ?se
animals to have been nurtured in anyhmited or secluded space
in the early stages of their development. The true Seals,
224 THE CHAIN OF LIFE.
which are more elevated than the Whales, and very different in
type, appear much later, and without any probable ancestry.
The Elephants, two or three species of which constitute in
the modern world the sole representatives of an order, are a
remnant of an ancient race once vastly more numerous. They
appear in Europe and Asia in the Miocene, when they were
represented by three distinct genera (Elephas, Mastodotiy and
Dinotheriiini). The second genus (Fig. i8i) differs from the
proper Elephants in having tuberculated teeth, indicating a
more swinish habit, and probably a more fierce disposition.
The third (Fig. 182) is remarkable for the immense size of some
of its species, far exceeding the modern Elephants, and has the
farther peculiarity of a pair of descending tusks on the lower
jaw, constituting a strong and heavy grubbing-hoe, with which
it could probably dig deeply for roots. So important was the
group in Miocene times that seven elephants are already known
from this formation in India alone, besides three species of
Mastodon. Four or five Miocene Mastodons are known in
Europe, besides two DinotherLi ; and the true Elephants appear
there in the Pliocene, and continue to the beginning of the
Modern. The elephantine animals are not known in America
till the Pliocene, but in that and the Pleistocene, and perhaps
up to the human period, the western continent, now altogether
destitute of elephants, possessed several species both oi Elephas
and Mastodon^ which extended, as in Siberia, even into the
krctic regions ; and, as we know from specimens preserved in
a frozen state in the latter region, some of the species were so
protected by dense fur as to be able to endure extreme cold.
The candid Gaudry closes his summary of the history and
affinities of the elephantine aiiimals with the words : '• How-
ever, the Lum of the differences compared with that of the
reseiiiblmres is too great to permit us to indicate any relation
of dencent between the proboscidians and the animals of other
orders known to us at present," So these greatest of all the
animals of the land, with their strangely specialised forms and
THE REIGN OF MAMMALS.
225
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226
THE CHAIN OF LIFE.
almost human sagacity, star.d alone, without father or mother,
without descent.
The Rodents, or gnawing animals, appear in the Early Eocene
on both continents in familiar forms allied to our Squirrels and
Rats. Porcupines and Beavers are added in the Miocene.
This group seems thus to have conilnued much as it was; and
it is still perhaps represented by as many snecies as at any
previous time. Many of the ancient forms were, however, much
B'lG. 182.— Head of Dinothe7i7t:n f:i;;antcuut.
Greatly reduced. Miocene of Eur. pc.
Kir,. 1 83. — Wing of Vespertilio
aquensis. An Eccene Hat.
After Gaudry.
larger than any modern species, and some of these larger forms '
present singular points of approach to very distinct types, as, for
example, to that of the Bears ; but these large and composite
F^ecie arc long since extinct. The insectivorous mammals
have much the same history with the Rodents. Such highly
^ For example, Tillotherittni of the American Eocene, which was as large
as a tapir, and in form resembled a bear.
THE REIGN OF MAMMALS. 227
specialised and abnormal forms as the Bats might be supposed
to be modern. But, strange to say, they appear with fully
developed wings both in Europe and America in the Eocene
(Fig. 183). Gaudry thinks that it is *' natural to suppose " that
there must have been species existing previously with shorter
fingers and rudimentary wings ; but there are no facts to support
this supposition, which is the more questionable since the sup-
posed rudimcnta.y wings would be useless, and perhaps harm-
ful to their possessors. Besides, if from the Eocene to the
present,, the Bats have remained the same, how long would it
take to develop an animal with ordinary feet, like those of a
shrew, into a bat ?
The F.arly Eocene was not altogether a time of peace in the
animal world. The old carnivorous Saurians were dead and
buried, but their place was taken by carnivorous mammals,
allied to our modern Tigers, Hyaenas, F^oxes, and Weasels.
The Carnivora, however, were subordinate in the Eocene, and,
as already remarked, some of them appear to be intermediate
between marsupial qnd placental forms — a fact which evolu-
tionists have noticed with much satisfactior They appear to
attain to their culmination in the Miocene, when their powers
seem to be proportionate to those of the great and well-armed
tjuadrupeds they had to deal with. To this age belongs the
introduction of the terrible " Cymetar-toothed Tiger" (Mac/i-
airodus^ Fig. 184). Its huge tusk-like canines and power-
ful limbs seem to fit it more than any other of the cat family
for destructive efficiency. Yet ordinary cat-like animMs were
contemporary with it, and have survived it, since Maciiairodus
disappears in the Post-Pliocene, though in previous periods it
had been very widely distributed on both continents. It is a
curious fact, perhaps of more significance in various ways than
we yet understand, that the Dog-bear {Arctocyon), of the oldest
French Eocene, believed to be the oldest placental mammal
known, though technically placed among the Carnivora, has a
kind of dnntition indicating that, like the modern Bears, it w'as
Q 2
228
THE CHAIN OF LIFE.
really omnivorous; and its skull shows some peculiarities
tending to those of the Marsupials.
Much interest attaches to the first appearance of the order of
Apes {Quadrumafia), or, if we take the somewhat deceptive
classification favor /ed by some modern zoologists, the Primates j
including the apes and man. They begin in the Eocene, both
in Europe and America, with the lowest tribe, that of the
Lemurs, now confined to the island of Madagascar and parts
Fig. 184. — Skull of a Cymetar-toothed H'i^^r^M achat rodus cultridcns). Pliocene,
France. Reduced.
of Africa and Southern Asia, and which may, Gaudry thinks,
be modified Marsupials, though he admits that this is hard to
understand. He mentions the resemblance of the teeth of
monkeys to those of some hog- like animals, a resemblance,
however, merely marking a similarity of food, and suggests on
this ground that some of the primitive ancestors of the hog
may have also given rise to the Monkeys. In the Miocene of
Europe and Asia we have true Apes ; and one of these, which
THE REIGN OF MAMMALS.
229
rivals man in stature {Dryopithecus) belongs to the group of
the gibbons, or long-armed apes, one of the higher families of the
modern Quadrmnana (Fig. 185). This animal presents, indeed,
the nearest approach to man made by any Tertiary mammal.
Still the differences are great, as, for instance, in the much
larger size of the canines and premolars. Yet so much con-
fidence has Gaudry in the resemblances, that he even ventures
to suggest that certain flint chips found in the Miocene of
Thenay, and which have been supposed to indicate human
Fir,. 185.— Lower Jaw of Dryopithecus Fontani. An Anthropoid Ape of the Middle
Miocene of France. Natural size.
workmanship, may have been chipped by the hands of
Dryopithecus. Should this view be adopted by evolutionists,
it will at least have the effect of preventing flint chips from
being received as evidences of the antiquity of man.
It is scarcely necessary to sum up this review of the history
of the Terti^~ ' mammals. Much that has been said may be
modified or changed by future discoveries ; but the great facts
of the late appearance of the placental mammals, of their
rapid introduction, with their ordinal differentiation nearly
230 THE CHAIN OF LIFE.
complete over all the continents, of the speedy culmination
and early decadence of many types, and of the unchanged
permanerce of others, must in the main be sustained. It is
not too much to say that to account for these facts tne evolu-
tionist must abandon the idea of gradual change, and adopt
that of " critical periods " when sudden changes occurred. The
history becomes inexplicable, unless with Mivart, Le Conte, and
Saporta, we admit " periods of rapid evolution " alternating
with others of stagnation or retrogression ; and if we admit
these, we practically fall back on the old idea of creation ; only
it may perhaps be " Creation by Law."
Note. — Professor Marsh has recently announced, in the American
Journal of Science., the discovery of a second small Marsupial mammal in
the Juras-ic of the Rocky Mountains, where it would seem that animals of
this kind were contemporary with the great reptiles of the genus
Atlantosaurus. The species described by Marsh are nearly related to
those found in the Jurassic of England. This is another curious case of
the simultaneous appearance of new forms of life in distant places.
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CHAPTER X.
THE ADVENT OF MAN.
HITHERTO we have met with no trace of man or of his
works. Yet there have been in our upward progress
from the dawn of life mute prophecies of his advent. Man is
in his bodily frame a vertebrate animal and a mammal ; and
when first the Amphibians were introduced in the Palaeozoic,
the framework of man's body was already sketched out and
its principles settled. Those great reptilian lords, the biped
Saurians of the Mesozoic, already foreshadowed his erect
posture, though their limbs may have been more ornithic than
mammalian. The gradual advance in the brain development
of the Tertiary mammals presaged a coming time when mind
would obtain the mastery over claw and tooth and horn ; and
in the Miocene ages there was already some hint of the precise
style of structure in which this new creative idea would be
realised. Yet it might have been impossible to imagine
beforehand the vast changes which this new idea would inau-
gurate. In the lower animals such intelligence as they possess
is so tied to the physical organisation that it manifests itself as
a mechanical unvarying instinct. Man bursts this bond, and in
doing so revoludonises the whole scheme of nature. Old things
are now put to new uses, the face of nature is changed, varied
arts are introduced, and thought enters into the domain of
234 THE CHAIN OF LIFE.
general and abstract truth. Objects are arranged, classified,
understood, and while in some respects the whole creation is
made to groan under the tyrannous inventions of man, yet
these are the inventions of imagination and design. They
are the triumph, not of brute force, but of will and
intelligence.
That man was not in all the earlier ages of the world, except
in these prophecies of his coming, geology assures us. That he
is, we know. How he came to be, is, independently of Divine
revelation, an impenetrable mystery — one which it is doubtful if
in all its bearings science will ever be competent to solve. Yet
there are legitimate scientific questions of great interest relat-
ing to the time and manner of his appearance, and to the con-
dition of his earlier existence and subsequent history, which
belong to geology, and in which so great stores of material
have been accumulated that a treatise rather than a chapter
would be required for their discussion. We may endeavour
to select a few of the more important points.
One of the first questions meeting us is that which relates
to the point in geological time signalise^ by the advent of our
species. In the Eocene period our continents were being gra-
dually raised out of the ocean, and were still in great part under
the waters, which several times returned upon the land, and
seemed ready again to engulf it. In this period not only have
we no traces of man, but all the higher animals of that age are
now extinct. In the later Eocene and Miocene the extent of
land became greater, but it was so disposed as to allow the
influx into the Arctic Sea of vast volumes of heated water from
the equatorial regions; and there may have been also astro-
nomical causes at work to increase this influx of warm water,
and so to raise the temperature of the Arctic regions still
higher.^ The middle period of the Tertiary was undoubtedly
a time very favourable to the wide distribution of the higher
forms of life both animal and vegetable. But we cannot trace
^ Croll, Climate and Time.
THE ADVENT OF MAN. 235
man or any of the contemporary mammals back to the Mio-
cene. In the Pliocene the continents had attained to their
present elevations, and climates were not dissimilar from those
prevail'-ig at present ; but still we have no certain indication
of the presence of man ; and if other modern mammals extend
back to this period their number is very small. In this age
also the greater part of the continents must have been covered
with a great thickness of soil and disintegrated rock favourable
to vegetation, and there seemed nothing to preclude the intro-
duction of man. But a new and at first sight most unfavourable
change was to intervene. Whether through internal changes
affecting the distribution of land and water, or through astro-
nomical vicissitudes, the northern hemisphere, and possibly the
whole world, entered on an era of refrigeration, the so-called
" Glacial Age " of the Post-Pliocene or Pleistocene period.
That in this period our continents as far south as the latitude
of 40° were overwhelmed with ice or ice-laden seas is rendered
evident by the fact that the whole surface up to several thou-
sands of feet above the sea-level has been bared of its accu-
mulated debris and polished and grooved by ice, and laden Avith
boulders and other glacial deposits, while in many places at
heights of even 1,000 or 1,200 feet these deposits contain sea-
shells of species now living in the colder parts of the ocean.
These phenomena do not exist in the tropical regions, except in
the vicinity of high mountains, but they recur in the southern
hemisphere. It is still uncertain whether the period of greatest
cold in the two hemispheres was at the same time or in
successive ages. Geologically, however, they are approximately
contemporaneous, both occurring between the end of the
Pliocene and the modern period ; but nevertheless they may
not have coincided in absolute date.
Very different views have been held as to the precise condi-
tion of the continents in the Glacial Age, though all agree in
the prevalence of cold and the action of ice, and in the fact
of a great submergence at one or more stages of the period.
236 THE CHAIN OF LIFE.
My own conclusions, which I have advocated elsewhere,^ and
which are based on extensive study of the northern parts of
America, where the deposits of this age are more widely
developed than elsewhere, are that there was one great subsi-
dence, leading to a condition in which the lower levels of the
continents were covered with ice-laden water and the higher
regions were occupied with permanent snow and glaciers. This
submergence went on till even high mountains 4,000 feet or
more in elevation were under water. Then there was a gradual
though intermittent elevation, during which the climate became
ameliorated, and lastly there was a condition in which the land
of the northern hemisphere stood higher than at present, and
which immediately preceded the modern period. As these con-
ditions have great significance with reference to the appear-
ance of man, I have tabulated them for reference as they occur
in Scandinavia, Great Britain, and North America. The so-
called " Interglacial Periods " of some geologists are in reality
local results of the stages of intermittent elevation in which
were deposited beds which in some cases, as m Scotland,
Sweden, and Eastern Canada, hold sea-shells, and in others,
as in the central areas of North America, contain remains of
plants of northern species.
We shall name, for convenience, the parts of this Pleistocene
revolution which include the great subsidence and glaciation,
the Glacial Age, that extending from the re-elevation to the
modern the Post-glacial.
The Glacial Age proved fatal to a large proportion of the
land life of the previous periods. According to Professor Boyd
Dawkins, out of fifty-three species known in Britain in the
Post-glacial, only twelve are survivors of the Pliocene; and
probably the proportions would not be greater in any part of
the northern hemisphere. Some, however, did survive, either
by migrating southward or by being inhabitants of places
less severely affected than most by the general cold and
* Notes on Post-Pliocene of Canada ; Acadian Geology^ 3rd edition.
THE ADVENT OF MAN.
237
submergence. There was thus no absolute break in the chain
of life effected by the Glacial Age.
Table of Pleistocene Deposits in Scandinavia, England, and
America. (Order descending.)
Scandinavia.
(Torell.)
Valley-clays and Heath-
sands of Sweden. (Nu
fossils.)
Terrace-gravels of Nor-
way and Sweden. (No
fossils.)
J)ryas-c!ay with Fossil
plants of northern
species.
Gkkat Britain.
(Lyell, etc.)
Hoxne Deposits and Upper
Terrace Clravels. Palaeo-
lithic Implements.
Upper Glacial Beds.
liricllinRt(m Beds.
Upper Boulder Beds.
So-called " Interglacial "
Deposits.
Uddevallabedswith Borea! Clyde Beds and Marine
Marine shells. Clays.
Yoldia Clay and Sand.
Arctic Marine Shells.
Yellow Stony Clay and
Sand, and Gravel of
Scania.
" Moraines de Fond," or
Boulder Clay proper.
Ancient Diluvial Sand.
Mid-Glacial Sands.
Till, or Older Boulder
Clay.
Pebbly Beds and Wey-
hurne Sands, Lignilic
Fcrest Beds.
NoKTU America.
'Terrace Gravels and Loess
Deposits.
Placer Gravels of West.
Do. Sand and Gravel,
Newer Boulder Drift.
So - called Interglacial
Beds, w'*': Plants, etc.
Loess Deposits of Missis-
sippi.
Upper Leda Clay and
Champlain Clay, wiih
Boreal Shells.
White Silts of British
Columbia.
Erie Clays and similar
Beds of West.
Lower Leda Clay, with
Arctic Shells.
Port Hudson Deposit of
Mississippi.
" Syrtensian " Beds of
New Brunswick.
Orange Sand of Mississippi.
Boulder Clays, with Local
and s jnie Travelled
Buulders.
Old Land Surfaces — Peat
under Boulder Clay,
Lccal Gravels and
bands.
Pre-glacial Gravels of
British Columbia.
238 THE CHAIN OF LIFE.
In what par, jf this sequence did man appear? In answer
to this, I think it is now generally admitted that he is not
certainly known earlier than the Post-glacial period. Various
supposed indications of his presence in " Inter-glacial " Glacial,
Pliocene, and even Miocene deposits have proved on examina-
tion to be unreliable. America has recently put forth claims
to have been inhabited by man in the Pliocene, on the faith
of remains found in auriferous gravels in the West. But the
facts that the implements and bones found are modern in
type, that the gravels were deeply mined by the Indians,
and that the objects found, as mortars for dressing gravel, etc.,
are in many cases such as they would be likely to leave in their
excavations, have discredited these supposed discoveries. Still
more recently, chipped flints found in gravels in New Jersey,
by Abbott, have been supposed to carry back the Indians of
the East coast to the Glacial period. It is evident, however, from
the description of these deposits by the late Mr. Belt and by
Professor Cook, director of the Survey of New Jersey, that
they are really Post-glacial, that their age must be estimated
by study of the local conditions, and that there is no good
ground for correlating them with the upper members of the
true Glacial drift to the northwards, with which they had been
somewhat rashly identified. Irrespective of the doubtful
character of many if not all of the so-called implements, th'i
deposits in which they are found is confessedly not a product
of the ice of the Glacial period proper, whether that was, as
some maintain, a period of land glaciation as far south as New
Jersey or not. It belongs to a time of denudation by water,
aided perhaps by floating ice, and is not necessarily older than
the river gravels of the Somme, which, like it, contain boulders
and imply conditions of torrential action and climate which
have long since passed away. If, however, these imple-
ments are genuine, they would imply the presence of Palceo-
cosmic or Antediluvian man in America. This would in itself
be an important discovery.
THE ADVENT OF MAN. 239
For the present, therefore, man is geologically a Post-
glacial species, and there is nothing unreasonable in suj)pos-
ing that he dates no farther back, since several animals his
contemporaries are in tin. same case ; and by supposing him to
have originated after the Glacial age we avoid the difficulties
attendant on his survival of that great revolution. The only
necessity for supposing an earlier appearance arises from the
requirements of the hypothesis of evolution. Those, however,
who hold this theory, may with Haeckel take refuge in that
shadowy continent supposed to have extended from Africa to
Australia,^ and to have sheltered man in his transition from the
ape to humanity, in the Tertiary period. The name Lcmuria is
taken from the Lemurs, supposed ancestors of the Apes, which
still haunt the margin of the Indian Ocean ; but it may be
taken also in its old Latin sense of ghosts of the evil dead ;
and as we are not likely to obtain any more tangible evidence
of the old natives of Lemuria, perhaps we may hope that some
spiritualist may succeed in charming them from the vasty deep
for our enlightenment. Should this be so, it is to be hoped
that no " drum ecclesiastic " will be beaten to chive them away
till they have revealed all they can tell.
It may be well to aaa that, in addition to ih'; negative evi-
dence, there is at least one positive evidence of the recent
origin of man which has been well urged by Le Conte. It is
this : animals have continued long in geological time in the
inverse ratio of their rank. Some Mesozoic protozoa still
survive. So do many early Tertiary mollusks. But the mammals
are of much less duration. No living species goes back
farther than the Pliocene. Few extend farther than the
Glacial age. On the same piiiiclple it is not to be expected
that man, the highest of all animals, should extend far back in
geological time.
^ The actual reason for belief in the past existence of land in the hasin
of the Indian Ocean is found in the close relationship of forms of life
found in Madagascar, Southern Asia, and Australia.
240 THE CHAIN OF LIFE.
Accepting the Post-glacial age as that of the advent of
man, it may be interesting to ask what we know of the condi-
tion of our continents when he appeared. In Western Asia,
in Europe, except in its more northern portions, and it would
now seem also in America, man had been introduced at a
time closely following the emergence of the land from the
Glacial sea. At this time the land area of both continents was
larger than it is at present, and the character of the fauna
shows that much of the surface was occupied with great steppes
or prairies, over which migration would be easy ; while there
were probably connections by land or chains of islands be-
tween the continents of the northern hemisphere. The land
animals of the continents were more numerous and of greater
stature than at present. Several species of elephants (Fig. i86)
and a rhinoceros roamed over the plains. The formidable
Elasmothe7-ium (Fig. 187),! an animal allied to the rhinoceros,
but more fleet and active, and of immense size, inhabited Asia
and Europe. Hippopotami, wild horses, the gigantic Irish
stag, several species of wild cattle, and bisons of greater size
than their successors, haunted the streams and steppes. The
cave bear, the cave lion, the spotted hjjena, and possibly the
Machairodus, were among the beasts of prey even in the
temperate latitudes. The climate must have been a continental
one, ranging through considerable extremes ; but the con-
ditions favoured migration of animals on the great scale, so
as to avoid these extremes^ and hence species of types now
comparatively restricted enjoyed a wide distribution.
To establish themselves in such a world, the primitive men
must have b(!en no puny race, either in mind or body, and they
must have been sheltered in some Eden of plenty and com-
parative safety till, by increase of numbers, invention of
weapons and implements, and domestication of useful animals,
they became able to cope with the monarchs of the waste.
^ Traditions of this animal, a veritable primaeval unicorn, are said still to
exist in Siberia.
THE ADVENT OF MAN.
241
00
ON
tq
p
242
THE CHAIN OF LIFE.
But this position once attained in the original seats of the
species, the wide continents presented great facilities for their
movements, and there were ample stores of food for wandering
tribes subsisting by the chase.
With such views the skeletons of the most ancient known
Fig. 187. — Tooth of Elasmotherium, Grinding surface, natural size. Siberia.
From Nature.
men ^ fully accord. They indicate a people of great stature, of
powerful muscular development, especially in the lower limbs,
of large brain, indicating great capacity and resources (Fig.
188), but of coarse Turanian features, like those of the tribes
^ As, for instance, those of Cro-Magnon, and Mentone, and Engis.
THE ADVENT OF MAN. 243
that now roam over the plains of Northern Asia (Fig. 189).
They used flint and bone implements, which they manufac-
tured with much skill (Figs. 190, 191). They were probably
clothed in dressed skins, ornamented with embroidery, in
the manner of the North American Indians. They used
shells and carved bones as ornaments. Recent discoveries
at Soloutre, in France, render it probable that some of
the tribes had tamed the horse, and resided in fortihed
villages. They buried their dead with offerings, indicating a
belief in immortality. These Post-glacial men are certainly
Fig. 188.— Engis Skull. Reduced.— After Lyell.
The Skull of one of the Men of the Mammoth age.
known as yet only in Europe; and we cannot therefore de-
termine if they represent the average man of the period.
There may have been dwarfish or degenerate tribes in the less
temperate climates. There may have been fruit-eating or
agricultural peoples in the more genial and fertile lands of the
east and south. The conditions above sketched are, I think,
fairly deducible from the facts stated by Christy and Lartet,
Dupont, Riviere, Dawkins, and others, who have studied the
remains of these early men, the Palxolithic nun of some
writers, or the men of the Mammoth age, and whom I have
R 2
244
THE CHAIN OF LIFE.
elsewhere named Palseocosmic men, as a term less objection-
able than those founded on implements not confined to any
age, or animals which may have long antedated man.
They were succeeded in Western Europe by a smaller and
less elevated race, identical apparently with the modem Lapps
and Basques, and in whose time the mammoth and many large
Fig. 189. — Outlines of Ihree Prehistoric European Skulls compared with an American
Skull from Hochelaga.
Outer outline. Cro-Magnon Skull. Second outline, Engis Skull. Third outline (dotted),
Neanderthal Skull. Inner figure, Hochelagan Skull on a smaller scale.
animals had disappeared, Europe had become clad with dense
forests, and the reindeer had extended his range far to the
south, while the land of our continents had become narrowed
to its present limits, or even less. The cause of these changes
must have been physical, and to some extent cataclysmal ; and
its wide-spread and effectual character is shown by the fact
THE ADVENT OF MAN.
245
that it exterminated so many animals of both continents which
had survived the Glacial age. Similar testimony is borne by
the occurrence of the implements and remains of Palaeocosmic
men in gravels and in diluvial clays in caverns, and by the
changes of level and deep erosions of valleys that are referable
to the close of the Palaeocosmic age. The most probable
agencies in this revolution were subsidences of the land, ac-
companied with climatal changes ; but the precise nature and
extent of these is still unknown ; and the prevalent tendency
on the part of geologists to stretch the doctrine of uniformity,
Fig. iqo.— Flint Implements found in Kent's Cavern, Torquay, under four feet of
cave mud and one foot of stalagmite.— After Pengelly.
so valuable within proper limits, to the absurd extreme of
excluding all changes not exemplified even in amount in the
modern period, will probably for some time prevent any
adequate conception of them.
It would be premature to correlate what is yet knOwn of the
Palaeocosmic age with historical periods ; but the tendency of
the facts accumulated is, I think, toward the identification of
the Palseocosmic men with the Antediluvians ; and their Neo-
cosmic successors, whether of the reindeer age, of the Danish
246
THE CHAIN OF LIFE.
shell-mounds, or the Swiss lake habitations, with Postdiluvian
and still existing tribes.
After what has been already said, it will be unnecessary to
dwell upon the characteristics of the first race of men known
to us. They were rude and uncivilised, in so far as outward
appliances are concerned ; but they are confessedly altogether
men, and in no respect akin to apes, and their
volume of brain is rather greater than that of
the average European of to-day ; so that they
must have had quite as much natural sagacity
and capacity for culture, and, like the modern
and historic Turanian nations, they were pro-
bably superior to the average European in the
instinct for art and construction. Thus if we
suppose these men derived from apes by any
process of gradual change, we must look for
their brute ancestors, not in the Pliocene or
Miocene, but in the Eocene itself. This
causes us to recur to the doctrine of critical
periods, when many species were introduced
together, alternating with periods of decay and
extinction. Post-glacial man appears at the end
of a time of sifting and trial, a time in which
Va vast number of species succumbed to great
physical reverses. No very great number of
species came in with him, and in the early
period of his history there was a decadence
Fig. 191.— Bone Har- * . •,,,,.,., ,
poon(Paiae()cosmic), or destruction Cither by the diluvial cataclysm
Cavern. "^°^ OT gradually. Out of ninety-eight species of
mammals contemporary with early man in
Europe, forty-one are wholly or locally extinct, and none have
been introduced except those brought by man himself. Thus
man stands alone, the grand product of his period and a lord
of creation, for whom great preparatory changes were made, and
multitudes of lower animals swept away to make room for him.
iA
THE ADVENT OF MAN. 247
According to our sacred Scriptures, this change is still imperfect,
and great additional ameliorations would have taken place but
for a moral catastrophe not within the domain of geology— the
fall of man. If we identify the Palceocosmic men with the
Antediluvians of the same venerable record, the roving
tribes whose remains are known to us represent that part of
the race of Cain of whom Jubal was the father, the nomads
dwelUng in tents, as distinguished from the settled agricultural
peoples. In this case, also, the catastrophe which destroyed
these rude and lawless men was that which culminated in the
deluge of Noah, which may represent the extinction of the last
great body of this primitive race, whose arts, handed down to
the physically inferior men of Postdiluvian times, astonish us
by their early development in Chaldaea and in Egypt.
If man is so recent geologically, he may still be very old
historically ; and the question remains, Have we any facts
bearing on the absolute antiquity of man? For the properly
historical aspect of this question, I may refer to the excellent
work of Canon Rawlinson on the Origin of Nations,^ which
shows conclusively that the historic origin of all the great
nations of antiquity extends backward less than 4,400 years
from our time. Beyond this we have, however, the Palseo-
cosmic or Antediluvian men ; and their extension backward
seems limited geologically only by the close of the Glacial
period, while many hold that the Genealogy in Genesis does
not require us to limit very narrowly their antiquity. The date
of the Glacial period is, however, at present very uncertain.
On the one hand, some geologists, like Lyell, have supposed
it may be as far back as 200,000 years ago. Others, like
Croll, are contented with the more moderate estimate of 80,000
years'. On the other hand, the calculations of Andrews, based
on the recession of the American lakes, and those of Winchell
on the recession of the Falls of St. Anthony, reduce the time
to from 7,000 to 12,000 years. It is impossible in the present
1 Religious Tract Society, 1878.
248
THE CHAIN OF LIFE.
.state of knowledge to settle these disputes ; but it may be
useful to refer shortly to some of the evidences which have
been adduced in favour of great antiquity.
We may, I think, at once take it for granted, that none of
the Neocosrnic races date farther back than the origin of the
great eastern nations. There are certainly no geological evi-
dences requiring a greater antiquity, for in their time the land
had attained to its present configuration, and the changes which
have occurred in the succession of forests and tlie growth of
peat are such as our experience in America shows to be
possibly quite modern. There is besides no doubt that these
people, from the Reindeer men of France and Belgium to the
people of the Swiss lakes, are modern races, whosj descendants
still live in Europe. We can thus limit our inquiry to the
Paiaeocosmic men ; and with respect to them we know only
what may be gathered from a consideration of the physical
changes which have occurred since they lived.
Tn Europe a great number of considerations have been
adduced as evidence of their high antiquity ; and these deserve
careful attention, though I think it will be found that they are
all liable to serious objections or great abatements on geological
grounds.
(i) The occurrence of human remains with those of animals
now extinct affords no certain evidence of antiquity. Ad-
mitting that human remains are found along with those of the
mammoth in Europe, and with those of the mastodon in
America, the question remains, How late did these cpecies
survive ? In Europe we know that several large animals now
extinct existed up to comparatively modern times. This is the
case with the Irish deer {Megaccros), the urus, the aurochs,
and the reindeer, in temperate Europe. How long previously
the mammoth or the hairy rhinoceros disappeared we do not
know, but need not suppose the time very long.
(2) The accumulation of sediment or of stalagmite over
human remains in caverns is not necessarily indicative of very
THE ADVENT OF MAN.
249
great antiquity. We know tliat in favourable circumstanceJi
mud, sand, and gravel may be rapidly deposited in caves by land
floods or river inundations, and that debris of various sorts
accumulates in such places from decay of rock and vegetable
and animal agencies. The deposition of stalagmite is also very
variable in its rate ; and the fact that it is being very slowly
deposited in any cave now does not prove that more rapid
deposition may not have taken place formerly. Dawkins and
others have ascertained a rate of a quarter of an inch i)er
annum in some caverns ; and this would allow the stalagmite
Fig. 192. — Sketch of a Mammoth, carved on a portion of a Tusk of the same Animal
(Lartet).
crust of Kent's cave, for which an antiquity of half a million of
years has been claimed, to have been formed in a thousand
years.
(3) The erosion of river valleys to great depths since the
Glacial period fails to establish the great antiquity of the caves
left on their sides or the high level gravels of their banks.
Throughout the northern hemisphere, the river valleys are of
old date, and were merely filled with loose detritus in the Glacial
age. The sweeping out of this debris would be a rapid process,
more especially when changes of level were occurring, and
when the rainfall was greater than at present. Besides, as Croll
250 THE CHAIN OF LIFE. ■
has well remarked, the actual configuration of our continents,
the amount of drift still remaining, and the imperfect manner
in which the river valleys have been cleared out, all testify to
the comparative recency of the Glacial period. ^ These con-
siderations would, indeed, materially reduce the antiquity
which he claims on astronomical grounds for the ice age.
(4) The growth of peat and the deposition of silt are very
deceptive as indications of great antiquity. For instance,
accurate observations made by a French engineer in the con-
struction of docks at St. Nazaire,^ show that in 1600 years the
Loire had deposited over Gallo-Roman rem.ains six metres of
mud. Relics of the Bronze age occur below these at a depth
indicating 500 years previously as their date ; and the beginning
of the modern deposit of the Loire would, on the same evidence,
be only 6000 years ago. Hilgard's observations on the delta of
the Mississippi in like manner tend greatly to reduce our esti-
mates of the time o upied in the deposit of the modern silt of
that river. The peat deposit at Abbeville, at the mouth of the
Somme, has been supposed to be a deposit requiring 30,000
years for its formation. But this estimate was based upon the
present rate of deposit ; and, as Andrews has shown, the fact
admitted by Boucher de Perthes, that birch stems three feet
high stand in this peat, implies a much more rapid deposit,
which is also proved by the depth at which Roman remains
have been found. In like manner the Scandinavian peats, to
which a fabulous antiquity has been ascribed, have been proved
to be comparatively modern by the depths at which metallic
works of art are found in them.
(5) The paucity of remains of Paloeocosmic men in Europe,
with their wide distribution, indicate that their sojourn was not
long, or that the population was very small and much scattered.
Even in a few thousands of years, an active and vigorous
1 Climate and Time, a work in which these and other matters relating to
the Glacial period are very well discussed.
2 Kimber, quoted by Southall.
\\
\
THE ADVENT OF MAN. 251
people, living in a country well supplied with food, must have
multiplied greatly, and must have left considerable remains. To
allow us to suppose that these men inhabited Europe even for
2,000 years, we have to suppose that the greater part of their
remains have been swept away, or remain under the waters, or
buried out of sight in diluvial sediments.
(6; Much importance has been attached to the early works
and high culture of Egypt and Chalda^a, as evidence of vast
time during which arts were growing from a supposed rude
stone age. But it must be observed that no such period is
known to antedate civilisation in the East, and that if the early
empires were established by survivors of the Deluge, they must
have brought with them the culture of Antediluvian times.
Farther, the notion of men emerging from a half-brutal state,
and from the use of the rudest implements, is purely conjectural
and not supported by facts. In America, where the semi-
civilised agricultural races are unquestionably the oldest, the
rudest possible implements were used by these partially civilised
agricultural people along with polished stone and metal ; and
Schliemann has shown that a rude stone age succeeded the
civilisation of Troy, and this at a time when Phoenicia and
Egypt were at the height of their civilisation. Such facts,
which might fill volumes, show how little value is to be attached
to supposed ages of rough and polished stone.
(7) The difficulties attending the establishment of geological
dates for deposits Hke those containing the remains of men are
very great. They are altogether superficial and local, not wide-
spread marine beds in which a distinct order of superposition
can be clearly traced. They are not easily separated from the
glacial beds below, or from those above which have beenrnodi-
fied by human agency, by land-floods, or by landslips. Thus
the application of geological criteria of age to them is very
difficult and uncertain. Evidence of this could easily be given,
in the many errors which have been promulgated, and which
have had to be retracted by their authors, or have been
253 THi: CHAIN OF LIFE.
disproved by the observations of others. For example, no
count y was at one time richer in supposed evidences of the
antiquity of man than Scandinavia ; but Professor Torell, the di-
rector of the Geological Survey of Sweden, has recently made a
careful re-examination of the facts, and has found that tlierc is
no evidence whatever of the existence of man in Scandinavia
before the Neolithic or polished stone age. There are, how-
ever, evidences of considerable changes of level since that
time, and it would seem even since the twelfth century of our
era. The remarkable and seemingly inexcusable errors of
observation referred to in Professor Torell' s memoir, should
enforce a caution on geologists as to the uncertainties of such
evidence. Lyell sifted the testimony bearing on this subject
with great care in the first edition of his Antiquity of Man.
In later editions he had to make large abatements, nnd now
much of the evidence in the latest edition would have to be
withdrawn or otherwise applied.
From all these considerations the conclusion is obvious that
while we have no certain data for assigning a definite number of
years to the residence of man on the earth, we have no geo-
logical evidence for the rash assertion often made that m com-
parison with historical periods the date of the earliest races of
men recedes into a dim, mysterious, and measureless antiquity.
On the basis of that Lyellian principle of the application of
modern causes to explain past changes, which is the stable
foundation of modern geology, we fail to erect any such
edifice as the indefinite antiquity of man, or to extend this
comparatively insignificant interval to an equality with the long
neons of the preceding Tertiary. The demand for such in-
definite extension of the history of man rests not on geological
facts, but on the necessities of hypotheses which, whatever
their foundation, have no basis in the discoveries of that science,
and are not required to account for the sequence which it
disposes.
CHAPTER XI.
REVIEW OF THE HISTORY OF LIFE.
WHAT general conclusions can we reach as to this long
and strange history of the progress of life on our
planet ? Perhaps the most comprehensive of these is that the
links in the chain of life, or rather in its many chains, are not
scattered and disunited things, but members of a great and
complex plan ; and that when we discern their combinations
and their pattern, we find them not only orderly an-' >^ymme-
trical, but all tending to one point and bound tc one central
object, even the throne of the Eternal. It must also appear
evident that the original plan of nature, both in the animal and
vegetable worlds, was too vast to be realised at one time on a
globe so limited as ours, but had to be distributed in time as
well as in space, thus realising the idea of time- worlds :
successive aeons in which, one after the other, the work of
creation could rise to successive stages of perfection and com-
pleteness till it culminated in man. All this is sufficiently
plain on the theistic view of nature, and may suffice for those
who reverently regard the God of nature as the Father of their
own spirits. But there are others who ask further questions.
Do wc know anything of the secondary causes and origin of
life, of the manner o^ its introduction and advance, of the laws
of its succession ?
254 THE CHAIN OF LIFE.
As to tlic first of these questions, it is certain that, up to
this time, the origination of the living being from the n.jn-
living is an inscrutable mystery. No one has witnessed this
change, or has been able to effect it experimentally. Nor have
we any direct evidence of the origination of one spec:ific type
from another. Such rensonings as assume the possilMlity of
tlicsc things, or on analogical grounds assert their probability,
belong rather to the domain of philosophicai speculation than
to science. As to the laws of the succession of life, however,
it is possible to learn something from the sccjuence of facts
as already ascertained ; and though much rem. ins to be dis-
covered, there are a few leading statements on this subject
which can already be made with safety.
Unity and uniformity, within the limits imposed by progress
and increasing complexity, can be affirmed of the whole
process. From the dawn of life to the present time the
great laws of i)hysical nature which oi)erate on animals and
T)larits have been uniform. These stable laws have regulated
the action of the outer world on organisms. The plans of
structure of these organisms laid down at the iirst have been
followeil throughout. Thus the succession of life presents
nothing fortuitous or arljitrary, but a continuous plan carried
out uniformly in time and space, with certain materials of fixed
properties, and with certain structures predetermined from the
first. There is, for example, a great sameness of ])lan throughout
the whole history of the marine invertebrate life of the Palaeo-
zoic. If we turn over the pages of an illustrated text-book of
geology, or examine the cases or drawers of a collection of
fossils, we shall find extending through every succeeding forma-
tion, representative forms of Crustaceans, Mollusks, and Corals,
in suc'i :■ manner as to indicate that in each successive i)erio(l
tliere has been a reproduction of the same type with modifica-
tions; and if the series is not continuous, this ai)pears to be
due to lack of specimens, or to abru}>t physical changes ; since
sometimes, where two formations pass into each other, we find
REVIEW OF THE HISTORY OF LIFE. 255
a gradual change in the fossils by the drojiping out and intro-
duction of species one by one. Thus in the whole of the
great TaJjcozoic period, both in its fauna and flora, we have
a continuity and similarity of a most marked character.
Tiiere is, indeed, nothing to i)reclude the supposition that
many forms reci^oned as species are really only race modifica-
tions. My own provisional conclusion, based on the study of
Palcxozoic plants, published many years ago,i is that the general
law will be fount! to be the existence of distinct specific types
independent of each other, but liable in geological time to
minor modifications, which have often been regarded as distinct
s])ecies.
While this unity of successive faunai at first sight presents
an appearance of hereditary succession, it loses much of this
character when we consider the number of new types in-
troduced without apparent predecessors, or ceasing witliout
successors, and the almost changeless persistence of other
ty])es; the necessity that there should be similarity of type in
successive fauna) on any hypothesis of a continuous plan ;
and, above all, the fact that the recurrence of ^-cpresentative
sjiecies or races in large proportion marks times of decadence
rather than of expansion in the types to which they belong. To
turn to a later period, this is very manifest in that singular
resemblance which obtains between the modern mammals of
South America and Australia and their immediate fossil pre-
decessors—the phenomenon being here manifestly that of
decadence of large and abundant species into a few dei)au-
perated representatives. This will be found to be a very
general law, elevation being accompanied by the abrupt
appearance of new types, rnd decadence by the apparent
continuation of old species, or modifications of them.
"''his resemblance with differenre in successive fimnrc also
connects itself very directly vvi.h the successive elevations and
depressions of our continental plateaus in geological time.
^ Report on Devonian Plants of Canada, 187 1.
256 THE CHAIN OF LIFE.
Pvvery great Palaeozoic limestone, for example, indicates a
depression with succeeding elevation. On each elevation
marine animals were driven back into the ocean, and on each
depression swarmed in over the land, reinforced by new
species, either then introduced or derived by migration from
other localities. In like manner on every depression, land
plants and animals were driven in upon insular areas,
and on re- elevation again spread themselves widely. Now I
think it will be found to be a law here that periods of expan-
sion were eminently those of introduction of new specific types,
and periods of contraction those of extinction, and also of
continuance of old types under new varietal forms. It must
also be borne in mind that all the leading tyj)es of invertebrate
life were early introduced, that change within these was neces-
sarily limited, and that elevation could take place mainly by
the introduction of the vertebrate orders. Sc i»^ plants, Cryp-
togams early attained their maximum as well as Gymnosperms,
and elevation occurred in the introduction of l^hiiinogams.
Another allied fact is the simultaneous appearance of like
types of life in one and the same geological ])eriod, over
widely separated regions of the earth's surface. This strikes
us especially in the comparatively simple and homogeneous
life-dynasties of the Pakiiozoic, when for exami)le we find the
same ty])es of Silurian Graptolites, 'i'rilobites and Brachiopods
appearing simultaneously in Australia, America, and ICurope.
Perhaps in no department is it more impressive than in the
introduction in the Devonian and Carboniferous ages of that
grand cryjitogamous and gymnospermous flora which ranges
from Brazil to Spitzbergen, and from Australia to Scotland,
accompanied in all by the same groups of marine invertebrates ;
or in the like wholesale })roduction of modern types of trees in
the Cretaceous. Such facts may depend either on that long
life of sijecific ty\)iii which gives them am))le time to s])read
to all possiJ)le habitats, before their extinction ; or on some
general law whceby the conditions suitable to similar types of
REVIEW OF THE HISTORY OF LIFE. 257
life emerge at one time in all parts of the world. Both cause,
may be mfluential, as the one does not exclude the other and
here ,s reason to believe that both are natural facts. Should
.t be Ml .matcly proved that species allied and representative,
but drstmct m ong.n, come into being simultaneously every!
where we shall arnve at one of the laws of creation, and one
probably connected with the gradual change of the physica'
conditions of the world. P"yi>icai
snede^'T/""'"^ "■""'.'' ""^ Periodicity of introduction of
Ssof , ^^";T u ^^^""'' or (lood-ti<Ies at particular
points of ,me while these great life-waves are followed and
preceded by t.mes of ebb in which little that is new is being
produced We labour in our investigation of this matter tmTer
he disadvantage that the modern period is evidently one of
hnt TX ^TV" •"'' "'^''™ """•'^' "'iJ o^r time been
that of he early I erfary or early Mesozoic, our views as to
the question of origin of species might have been very differ-
ent, t IS a striking fact, in illustration of this, that since the
Glacial age no new species of mammal can be proved to have
originated on our continents, while a great number of large
and conspicuous forms have disappeared. It is possible that
he proximate or secondary causes of the ebb an.l flow of
life-production may be in part at least physical; but
other and more important efficient causes may be behind
these. In any case these undulations in the history of life
are in harmony with much that we see in other departments
oi nature. '■
It results from the above and the immediately preceding
statement that specific and generic types enter on the stage
in great force, and graduiilly taper off toward extinction. They
should so appear in the geological diagrams made to illustrate
the succession of life. This applies even to those forms of life
which corne in with fewest- species and under the most humble
gu.se What a remarkable swarming, for example, there must
have been of Marsupial Mammals in the early Mesozoic ; and
s
258 THE CHAIN OP^ LIFE.
in the Coal formation the only known Pulmonates, four or
five in number, belong to as many generic types.
I have already referred to the permanence of certain species
in geological time. I may now place this in connection with
the law of origination and more or less continuous transmission
of varietal forms. I may, perhaps, best illustrate this in con-
nection with a group of species with which I am very familiar,
that which came into our seas at the !)eginning of the Olacial
age, and still exists. With regard to their permanence, it can
be affirmed that the shells now elevated in Wales to 1,200 and
in Canada to 600 feet above the sea, and which lived before
the last great revolution of our continents, a period vastly
remote as compared with human history, differ in no tittle from
their modern successors after thousands or tens of thousands
of generations. It can also be affirmed that the more variable
species api>ear under precisely the same varietal forms then as
now, though these varieties have changed much in their local
distribution. I'he real import of these statements, which might
also be made with regard to other groups well known to palae-
ontologists, is of so great significance that it can be rea.lised
only after we have thought of the vast time and numerous
changes through which these humble creatures have survived.
I may call in evidence here a familiar British and American
animal, the common sand clam, Mya aufmria, and its relative,
Mya truHcaia, which now inhabit together all the northern
seas; for the Pacific specimens, from Japan and California?
though differently named, are undoubtedly the same. Mya
truncata appears in Europe in the older Pliocene, and was
followed by M. arenaria a little later. Both shells occur in
the Pleistocene of America, and their several varietal forms
had then already developed themselves, and remain the
same to-day ; so that these humble mollusks, littoral in their
habits, and subjected to a great variety of conditions, have
continued, perhaps for one or two thousand centuries, to con-
struct their shells precisely as at present. Nor are there any
REVIEW OF THE HISTORY OF IJFE. 259
indications of a transition between the two species. Similar
statements may be made witli regard to other moliusks of the
Pliocene and Modern periods, and there are even species
which extend unchanged from the early Eocene. Nor is it
impossible that some modern bivalves of the IJrachiopod
group may be scarcely modified descendants even of Palieozoic
species.
Perhaps some of the most remarkable facts in connection
with the permanence of species and varietal forms arc those
lurnished by that magnificent flora which burst in all its
majesty on the American continent in the Cretaceous period,
and still survives among us even in some of its specific types.
say survives; for we have but a remnant of its forms living
and comparatively little that is new has probably been added
since. Take, for example, the facts stated in Chapter VI 1 1.
as to the continuance to the present time of species of plants
introduced in the Cretaceous and Eocene, and which thus came
in at the very time when the great Mesozoic reptiles were
decaying or had just disappeared, and when the placental
mammals were being introduced. Some of these plants mu; ^
have propagated themselves unchanged for half a million ot
years.
Plants and the lower tribes of animals are, however more
permanent than the higher animals ; and a strange cr,ntrast
IS afforded to the foregoing examples of persistence by the
repeated revolutions that have affected vertebrate life since
the Mesozoic age. Yet even in the case of vertebrates there
seems to have been little change, except in the extinction of
species, since the Pliocene period.
In conclusion of this review, r m we formulate a few of the
general laws, or perhaps I had better call tlicm the general
conclusions respeciu-' life, in which all pahcontologists may
agree. Perhaps it is not possible to do this at i)resent satis-
factorily, but the attempt may do no harm. We my, then,
I think, make llie following affirmations :—
s 2
26o TIIK CHAIN OF LIFE.
(i) The existence of life and organisation on the earth is not
eternal, or even coeval with the beginning of the physical uni-
verse, but may possibly date from I.aurcntian or immediately
prc-T.aurentian times.
(2) The introduction of new .Sj)ecies of animals and plants
has been a continuous process, not necessarily in the sense of
derivation of one species from another, but in the higher sense
of the continued operation of the cause or causes which intro-
duced life at first. This, as already stated, I take to be the
true theological or Scriptural as well as scientific idea of what
we ordinarily and somewhat loosely term creation.
(3) Though thus continuous, the process has not been uni-
form ; but periods of rapid production of species have alter-
nated with others in which many disappeared and few were
introduced. This may have been an effect of physical cycles
reacting on the progress of life.
(4) Species, like individuals, have greater energy and vitality
' . their younger stages, and rapidly assume all their varietal
<;rms, and extend themselves as widely as external circum-
stances will permit. Like individuals, also, they have their
periods of old age and decay, though the life of some species
has been of enormous duration in comparison with that of
others ; tlie difference appearing to be connected with degrees
of adaptation to different conditions of life.
(5) Many allied species, constituting groups of animals and
plants, have made their appearance at once in various parts
of the earth, and these groups have o])eyed the same laws
with the individual and the species in culminating rapidly, and
then slowly diminishing, though a large group once introduced
has rarely disappeared altogether.
(6) ( J roups of species, as genera and orders, do not usually
begin with their highest or lowest forms, but with interme-
diate and generalised types, and they show a capacity for both
elevation and degradation in their subsequent history.
(7) The history of life presents a progress from the lower to
REVIEW OF THE HISTORY OF LH-E. 261
the higher, and from the simpler to the more complex, and
from the more generalised to the more specialised. In this
progress new types are introduced, and take the place of the
older ones, which sink to a relatively subordinate place, and
become thus degraded. Jiut the physical and organic changes
have been so correlated and adjusted that life has not only
always maintained its existence, but has been enabled to assume
more complex forms, and that older forms have been made to
prepare the way for newer, so that there has been on the whole
a steady elevation culminating in man himself. Elevation and
specialisation have, however, been secured at the expense of
vital energy and range of adaptation, until the new element of
a rational and inventive nature was introduced in the case
of man.
(8) In regard to the larger and more distinct types, we cannot
find evidence that they have, in their introduction, been jjre- ^
ceded by similar forms connecting them with previous groups ;
but there is reason to believe that many sujiposed representa-
tive species in successive formations are really only races or
varieties.
(9) In so far as we can trace their history, specific types are ^
l)ernjai.ent in their characters from their introduction to their
extinction, and dieir earlier varietal forms are similar to their
later ones.
(10) Palaeontology furnishes no direct evidence, perhaj)s never
can furnish any, as to the actual transformation of one sjiecies
into another, or as to the actual circumstances of creation of a
species, but the drift of its testimony is to show that species
come in J>er saltum^ rather than by any slow and gradual
process.
(11) The origin and history of life cannot, any more than the
origin and determination of matter and force, l)c explained on
l)urely material grounds, but involve the consideration of power
referable to the unseen and spiritual world.
Different minds may state these principles in different ways,
262 THE CHAIN OF LIFE.
but I believe that in so far as palaeontology is concerned, in
substance they must hold good, at least as steps to higher
truths. And now I may be permitted to add that we should
be thankful that it is given to us to deal with so great questions,
and that in doing so deep humility, earnest seeking for truth,
patient collection of all facts, self-denying abstinence from
hasty generalisations, forbearance and generous estimation with
regard to our fellow-labourers, and reliance on that Divine Spirit
which has breathed into us our intelligent life, and is the source
of all true wisdom, are the (jualities which best become us.
As we have traced onward the succession of life, reference
has been made here and there to the defects of those bold
theories of descent with modification which are held forth in
our time as the true bond of the links of the chain of life. It
must have been apparent that these theories, however specious
when placed in connection with a limited induction of facts
selected for the purpose of illustrating them, are very far from
affording a satisfactory solution of all difficulties. They can-
not perhaps be expected to take us back to the origin ot
living beings; but they also fail to explain why so vast
- numbers of highly organised species* struggle into existence
simultaneously in one age and disappear in another, why no
J continuous chain of succession in time can be found gradually
blending species into each other, and why in the natural
' succession of things degradation under the influence of ex-
ternal conditions and final extinction seem to be laws ot
organic existence. It is useless here to appeal to the imper-
fection of the record or to the movements or migrations ot
species. The record is now in many important parts too
complete, and the simultaneousness of the entrance of the
faunas and floras too certainly established, while the moving
of species from place to place only evades the difficulty. The
truth is that such hypotheses are at present premature, and that
we require to have larger collections of facts. Independently
of this, however, it would seem that from a philosophical
REVIEW OF THE HISTORY OF LIFE. 263
point of view all theories of evolution, as at present applied
to life, are fundamentally defective in being too partial in
their character; and this applies more particularly to those
which are "monstic" or "agnostic," and thus endeavour to
dispense with a Creative Will behind nature. It may be
instructive to illustrate from the facts developed in preceding
chapters this feature of most of the attempts at generahsation
on this subject.
First, then,* these hypotheses are too partial, in their ten-
dency to refer numerous and complex phenomena to one
cause, or to a few causes only, when all trustworthy analogy
would indicate that they must result from many concurrent
forces and determinations of force. We have of late been
ver)' familiar with those ingenious, not to say amusing, specula-
tions in which some entomologists and botanists have indulged
with reference to the mutual relations of flowers and haustellate
insects. Geologically the facts oblige us to begin with Cryp-
togamous plants and mandibulate insects ; and out of the
desire of insects for non-existent honey, and the adaptations of
plants to the requirements of non-existent suctorial apparatuSj
we have to evolve the marvellous complexity of floral form
and colouring, and the exquisitely delicate apparatus of the
mouths of haustellate insects. Now when it is borne in mind
that this theory implies a mental confusion on our part pre-
cisely similar to that which in the department of mechanics
actuates the seekers for perpetual motion, that we have not the
smallest tittle of evidence that the changes required have
actually occurred in any one case, and that the thousands of
other structures and relations of the plant and the insect have
to be worked out by „ series of concurrent evolutions so
complex and absolutely incalculable in the aggregate that the
cycles and epicycles of the Ptolemaic astronomy were child's
play in comparison, we need not wonder that the common
sense of mankind revolts against such fancies, and that we are
accused of attempting to construct the universe by methods
264 THE CHAIN OF LIFE.
that would bafile Omnipotence itself, because they are simply
absurd. In this aspect of them, indeed, such speculations arc
necessarily futile, because no mind can grasp all the complexities
of even any one case, and it is useless to follow out an imaginary
line of development which unexplained facts must contradict
at every step. This is also no doubt the reason why all
recent attempts at constructing " Phylogcnies " are so change-
able, and why no two experts can agree about almost any
of them.
A second aspect in which such speculations are too partial
is in the unwarranted use which they make of analogy. It is
not unusual to find such analogies as that between the em-
bryonic development of the individual animal and the succession
of animals in geological time placed on a level with that
reasoning from analogy by which geologists apply modern
causes to explain geological formations. No claim could be
more unfounded. When the geologist studies ancient lime-
stones built up of the remains of corals, and then applies the
phenomena of modern coral reefs to explain their origin, he
brings the latter to bear on the former by an analogy which
includes not merely the apparent results but the causes at work,
and the conditions of their action ; and it is on this that the
validity of his comparison depends, in so far as it relates to
similarity of mode of formation. But when we compare the
development of an animal from an embryo cell with the pro-
gress of animals in time, though we have a curious analogy as
to the steps of the process, the conditions and agents at work
are known to be altogether dissimilar, and therefore we have
no evidence whatever as to identity of cause, and our reasoning
becomes at once the most transparent of fallacies. Farther,
we have no right here to overlook the fact that the conditions
of the embryo are determined by those of a previous adult,
and that no sooner does this hereditary potentiality produce a
new adult animal than the terrible external agencies of the
physical world, in presence of which all life exists, begin to
REVIEW OF THE HISTORY OF LIFE. 26S
tell on the organism, and after a struggle of longer or shorter
duration it succumbs to death, and its substance returns into
inorganic nature, a law from which even the longer life of tlie
species does not seem to exempt it. All this is so plain and
manifest that it is extraordinary that evolutionists will con-
tmue to use such partial and imperfect arguments. Another
example may be taken from that application of the doctrine
of natural selection to explain the introduction of species in
geological time which is so elaborately discussed by Sir C.
Lyell in the last edition of his rrimiples of Geology. The
great geologist evidently leans strongly to the theory, and
claims for it the "highest degree of probability," yet he per-
ceives that there is a serious gap in it ; since no modern fact
has ever proved the origin of a new species by modification.
Such a gap, if it existed in those grand analogies by which
we explain geological formations through modern causes, would
be admitted to be fatal.
A third illustration of the partial character of these hypo-
theses may be taken from the use made of the theory deduced
from modern physical discoveries, that life must be merely a
product of the continuous operation of physical laws. The
assumption, for it is nothing more, that the phenomena of life
are produced merely by some arrangement of physical forces,
even if it be admitted to be true, gives only a partial explana-
tion of the possible origin of life. It does not account for the
fact that life as a force or combination of forces is set in
antagonism to all other forces. It does not account for the
marvellous connection of life with organisation. It does not
account for the determination and arrangement of forces im-
plied in life. A very simple illustration may make this plain.
If the problem to be solved were the origin of the mariner's
compass, one might assert that it is wholly a physical arrange-
ment both as to matter and force. Another might assert that
it involves mind and intelligence in addition. In some sense
both would be right. The properties of magnetic force and of
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266 THE CHAIN OF LIFE.
iron or steel are purely physical, and it might ev^n be within
the bounds of possibility that somewhere in the universe a
mass of natural loadstone may have been so balanced as to
swing in harmony with the earth's magnetism. Yet we should
surely be regarded as very credulous if we could be induced to
believe that the mariner's compass has originated in that way.
This argument applies with a thousandfold greater force to
the origin of life, which involves even in its simplest forms so
many more adjustments of force and so much more complex
machinery.
Fourthly, these hypotheses are partial, inasmuch as they fail
to account for the vastly varied and correlated interdepen-
dencies of natural things and forces, and for the unity of plan
which pervades the whole. These can be explained only by
taking into the account another element from without. Even
when it professes to admit the existence of a God, the evolu-
tionist reasoning of our day limits itself practically to the
physical or visible universe, and leaves entirely out of sight the
power of the unseen and spiritual, as if this were something
with which science has nothing to do, but which belongs only
to imagination or sentiment. So much has this been the case
that when recently a few physicists and naturalists have turned
to this aspect of the subject, they have seemed to be teaching
new and startling truths, though only reviving some of the
oldest and most permanent ideas of our race. From the
dawn of human thought it has been the conclusion alike of
philosophers, theologians, and the common sense of mankind,
that the seen can be explained only by reference to the unseen,
and that any merely physical theory of the world is necessarily
partial. This, too, is the position of our sacred Scriptures, and
is broadly stated in their opening verse ; and indeed it lies alike
at the basis of all true religion and all sound philosophy, for it
must necessarily be that " ths things that are seen are temporal,
the things that are unseen, eternal." With reference to the
primal aggregation of energy in the visible universe, with
REVIEW OF THE HISTORY OF LIFE. 267
reference to the introduction of life, with reference to the soul
of man, with reference to the heavenly gifts of genius and
prophecy, with reference to the introduction of the Saviour
Himself into the world, and with reference to the spiritual gifts
and graces of God's people, all these spring not from sporadic
acts of intervention, but from the continuous action of God
and the unseen world ; and this, we must never forget, is the true
ideal of creation in Scripture and in sound theology. Only in
such exceptional and little influential philosophies as that ot
Democritus, and in the speculations of a few men carried off
their balance by the brilliant physical discoveries of our age,
has this necessarily partial and imperfect view been adopted.
Never indeed was its imperfection more clear than in the light
of modern science.
Geology, by tracing back all present things to their origin^
was the first science to establish on a basis of observed facts
the necessity of a beginning and end of the world. But even
physical science now teaches us that the visible universe is a
vast machine for the dissipation of energy ; that the processes
going on in it must have had a beginning in time, and that all
things tend to a final and helpless equilibrium. This necessity
implies an unseen power, an invisible universe, in which the
visible universe must have originated, and to which its energ"
is ever returning. The hiatus between the seen and the unseen
may be bridged over by the conceptions of atomic vortices of
force, and by the universal and continuous ether ; but whether
or not, it has became clear that the conception of the unseen
as existing has become necessary to our belief in the possible
existence of the physical universe itself, even without taking
life into the account.
It is in the domain of life, however, that this necessity be-
comes most apparent; and it is in the plant that we first
clearly perceive a visible testimony to that unseen which is the
counterpart of the seen. Life in the plant opposes the outward
rush of force in our system, arrests a part of it on its way, fixes
268 THE CHAIN OF LIFE.
it as potential energy, and thus, forming a mere eddy, so to
speak, in the process of dissipation of energy, it accumulates
• that on which animal life and man himself may subsist, and
assert for a time supremacy over the seen and temporal on
behalf of the unseen and eternal. I say, for a time, because
life is, in the visible universe, as at present constituted, but a
temporary exception, introduced from that unseen world where
it is no longer the exception but the eternal rule. In a still
higher sense, then, than that in which matter and force testify
to a Creator, organisation and life, whether in the plant, the
animal, or man, bear the same testimony, and exist as outposts
put forth in the succession of ages from that higher heaven that
surrounds the visible universe. In them, as in dead matter,
Almighty power is no doubt conditioned by law, yet they bear
more distinctly upon them the impress of their Maker, and
while all explanations of the physical universe which refuse
to recognise its spiritual and unseen origin must necessarily
be partial and in the end incomprehensible, this destiny falls
more quickly and surely on the attempt to account for life and
its succession on merely materialistic principles.
Here, however, we must remember that creation, as main-
tained against such materialistic evolution, whether by theology,
philosophy, or Holy Scripture, is necessarily a continuous,
nay, an eternal influence, not an intervention of disconnected
acts. It is the true continuity, which includes and binds
together all other continuity.
It is here that natural science meets with theology, not as an
antagonist, but as a friend and ally in its time of greatest need ;
and I must here record my belief that neither men of science
nor theologians have a right to separate what God in Holy
Scripture has joined together, or to build up a wall between
nature and religion, and write upon it "no thoroughfare."
The science that does this must be impotent to explain nature
and without hold on the higher sentiments of man. The
theology that does this must sink into mere superstition.
REVIEW OF THE HISTORY OF LIFE. 269
In the light of all these considerations, whether bearing on
our knowledge or our ignorance, a higher and deeper question
presents itself, namely, that as to the relation of nature and of
man to a Personal Creator. To this it seems to me that the study
of the succession of life yields no uncertain reply. Call the pro-
gress of life an evolution if you will ; trace it back to primaeval
Protozoa, or to u congeries of atoms : still the truth remains that
nothing can be evolved out of these primitive materials except
what they originally contained. Now we find in the existence
of man, and in the tendency of the scheme of nature towards
his introduction, evidence that at least all that is involved in
the reasoning and moral nature of man must have existed
potentially before atoms began to shape themselves into crystals
or into organic forms. Nay, more than this is implied, for we
do not know that man and what he has hitherto been and
done constitute the ultimate perfection of nature, and we must
suspect that something much more than what we see in man
must be required for the origination of the chain of life.
What does this prove, in any sense in which human reason
can understand it ? Nothing less, it seems to me, than that
doctrine of the Almighty Divine Logos, or Creative Reason, as
the cause of all things, asserted in our sacred Scriptures, and
held in one form or another by all the greatest thinkers who
have attempted to deal with the question of origins. Falling
back on this great truth, whether presented to us in the simple
** God said " of Genesis, or in the more definite form of the
New Testament, '* The Word was with God, and the Word was
God," we find ourselves in the presence of a Divine plan per-
vading all the ages of the earth's history and culminating in
man, who presents for the first time the image and likeness of
the Divine Maker ; and this forms the true nexus of all the
separate chains of life. Had man never existed, such reason-
ing might have been speculative merely, but the existence of
man, taken in connection with the progress of the plan which
has terminated in his advent, proves the existence of God.
270 THE CHAIN OF LIFE.
Divine revelation carries us a step farther, and teaches us to
recognise in Jesus of Nazareth God manifest in the flesh, the
Divine Logos dwelling among men. But though this is a doc-
trine of revelation and not of science, it is in perfect harmony
with the plan of progress which we have been sketching. It is
the natural outcome of a process leading to the introduction
of a rational and accountable being, understanding some-
thing of the works and ways of God, that to him God should
reveal Himself, and that the Divine Logos, by whom were
" constituted the ages " ^ of the world's geological history,
should preside also over its future consummation, when all
the degradation that has sprung from the aberrations of fallen
and imperfect humanity shall be removed, and man himself
shall become fully a partaker of the Divine nature.
The world we live in is thus not necessarily a finished world,
and it is now marred by the sins of man. What it may be in
the future, we can perhaps as little guess as an intelligence
studying the Palaeozoic world could have understood that of
the present time. But it is a glorious truth to know that our
Maker has revealed Himself to us also as a Saviour, and that
as individuals we shall not perish, to be replaced by an im-
proved species in the future, but that we ourselves, as sons of
God, may enter into and possess the new earth and new
heavens of future aeons of the universe. Thus it would seem
that the Gospel of Jesus Christ is that which was wanting
to complete and justify the history of nature by bringing to
light the final " restitution of all things," and our own union to
God in a happy immortality.
^ The true meaning of Hebrews i. 2 and xi. 3.
' INDEX.
{Principally to Forms of Life noticed or illustrated.)
Agnostus, 79
Alethopteris, 105
Ammonites, 76
Amphibians, 152
Amphipeltis, 85
Ancyloceras, 77
Antholithes, loi
Anthozoa, 57
Angiosperms, 187
Anthropalaemon, 85
Antiquity of Man, 247
Apes, 228
Arachnida, 150
Archaeocyathus, 37
Archaeopteryx, 172
Archegosaurus, 153
Archimulacris,' 146
Arctocyon, 227
AsterophylJites, 103
Astylospong^a, 51
Athyris, d'j
Baculites, 77
Baphetes, 155
Bathygnathus, 174
Batrachians, 152
Bats, 226
Beetles, 145
Beginning of Life, 23
Belemnites, 78
Beryx, 133
Beyrichia, %2,
Birds, 172
Bivalve shells, 69
Blattina, 146
Brachiopods, djt
Brontotherium, 217
Buthotrephis, 92
Butterflies, 150
Calamites, 99, 104
Calymene, 80, 82
Campsognathus, 179
Carcharodon, 132
Cardiocarpum, loi
Cephalaspis, 122
Cephalopods, 'ji
Ceratites, 75
Ceratodus, 126
Ceteosaurus, 178
Cinnamomum, 198
Clidastes, 169
Cockroaches, 146
Conocephalites, 79
Conodonts, 118
Corals, 55
Cordaites, 88
Cory^hodon, 214
Crinoids, 611
Criocera;s, 77
Criistacep, 79
Cuttle-fishes, 71
Cyathaspis, 121
Cyathophyllum, 60.
Cystideans, 62
Cythere, 83
Dadoxylon, 100
Dapedius, 132
Davallia, 192
Dictyonema, 53
Bikellocephalus, 79
Dinichthys, 127
Dinoceras, 215
Dinosaurs, 174
Dipnoi, 123
Discina, 66
Dragon-fly, 148
Dromatherium, 209
Dryopithecus, 229
ECHINODERMS, 61
Elasmotherium, 242
Elephants, 224
Eocene age, 213
Eopteris, 93
Eoscorpius, 151
Eozoon, 27
Equine feet, 218
Equisetaceae, 97
Extracrimis, 64
Favosites. 59
Ferns of Palicozoic, 105
Ferns, Tree, 97
Fishes, 120
Floras, distribution of,
201
Footprints, 152
Foraminifera, 32
Fruits of Devonian, 10 1
Ganoids, 120
Gastropods, 70
Glacial age, 233
Glyptccrinus, 63
Glyptodendron, 94
Gomphoceras, 73
Graptolites, 53
//
272
IIalisites, 59
Heliophyllum, 59
Heterocrinus, 63
Horse, 218
Huronian age, 24
Hydrozoa, 54
Hylonomus, 157
Ichthyosaurus, 167
Implements, 245
Insects, 139
Isotelus, 82
Labyrinthodonts, 155
Lamellibranchiata, 69
Lampreys, 117
Land- snails, 142
Laurentian age, 24
Lepidodendron, 108
Lepidosiren, 124
Leptophleum, 98
Libellula, 148
Lingula, 65
Liriodendron, 191
Lituites, 73
Loligo, 72
Machairodus, 227
Mammals, 207
Mammoth, 240
Man, advent of, 233
Mantids, 146
Mares-tails, 97
Marsupials, 207
Mastodon, 224
May-flies, 146
Megalosaurus, 176
Megaphyton, 107
Megatherium, 222
Microlestes, 208
Microsauria, 156
Millepedes, 145
Modern forests, 1 86
Monotremes, 208
Mososaurus, 169
INDEX.
Moths, 148
Murchisonia, 70
Myrica, 194
Nautilus, 71
Neuropteris, 105
Oldhamia, 52
Onchus, 121
Onoclea, 191
Oreodon, 221
Origin of Life, 23
Orthis, 66
Orthoceras, 73
Osteolepis, 124
Ostracods, 83
Otodus, 131
Pal^.aster, 62
Paloechinus, 62
Paloeoniscus, 129
Palaeotherium, 21 1
Paradoxides, 79
Pentacrinus, 64
Phaceps, 83
Phascolotherium, 210
Pinnularia, 101
Plagiaulax, 210
Plants, earliest, 89
Pleistocene, 240
Plesiosaurus, 167
Pleurocystites, 63
Pleurotomariri, 70
Pliosaurus, 168
Pclyzoa, 59
Post-glacial, 236
Prodryas, 150
Productus, 68
Protannularia, 91
Proterosaurus, 166
Protostigma, 92
Protozoa, 27
Psilophyton, 95
Pterichthys, 123
Pterodactyls, 171
Pteropode, 70
Pterygotus, 84
Ptilodictya, 55
Ptyonius, 154
QUADRUMANA, 228
Quercus, 194
Receptaculites, 38
Reptiles, 165
Rhamphorhyncus, 171
Rhizopods, 34
Ruschinites, 81
Sassafras, 190
Scorpions, 15 1
Si'a-lizards, 167
Selachians, 130
Sequoia, 197
Sharks, 1 20
Sigillaria, 109
SpUenophyllum, 92, 103
Sphinx-moth, 149
Spirifer, 67
Sponges, 48
Squids, *J2.
Stelliosaurus, 158
Stenopora, 57
Stromatopora, 36
Syringoxylon, 102
Tabulata, 59
Teliosts, 120
Terebratula, 66
Trichospongia, 51
Trigonocarpum, loi
Trilobites, 78
Turrilites, 77
Xylobius, 145
Zaphrentis, 60
Zonites, 143
LONDON : K. CLAY, SONS, AND TAYLOR, PRINTERS.