may be recognized by the superposition of the sedimentary, metamorphic, and
conglomerate strata; by the nature of the formations traversed by the
erupted masses, and -- with the greatest certainty -- by the presence of
organic remains and the differences of their structure. The application of
botanical and zoological evidence to determine the relative age of rocks --
this chronometry of the earth's surface, which was already present to the
lofty mind of Hooke -- indicates one of the most glorious epochs of modern
geognosy, which has finally, on the Continent at least, been emancipated
from the sway of Semitic doctrines. Palaeontological investigations have
imparted a vivifying breath of grace and diversity to the science of the
solid structure of the earth.
The fossiliferous strata contain, entombed within them, the floras and
faunas of by-gone ages. We ascend the stream of time, as in our study of
the relations of superposition we descend deeper and deeper through the
different strata, in which lies revealed before us a past world of animal
and vegetable life. Far-extending disturbances, the elevation of great
mountain chains, whose relative ages we are able to define, attest the
p 271
destruction of ancient and the manifestation of recent organisms. A few of
these older structures have remained in the midst of more recent species.
Owing to the limited nature of our knowledge of existence, and from the
figurative terms by which we seek to hide our ignorance, we apply the
appellation 'recent structure' to the historical henomena of transition
manifested in the organisms as well as in the forms of primitive seas and of
elevated lands. In some cases these organized structures have been
preserved perfect in the minutest details of tissues, integument, and
articulated parts, while in others, the animal, passing over soft
argillaceous mud, has left nothing but the traces of its course,* or the
remains of its undigested food, as in the coprolites.**
[footnote] *[In certain localities of the new red sandstone, in the Valley
of the Connecticut, numerous tridactyl markings have been occasionally
observed on the surface of the slabs of stone when split asunder, in like
manner as the ripple-marks appear on the successive layers of sandstone in
Tilgate Forest. Some remarkably distinct impressions of this kind, at
Turner's Falls (Massachusetts), happening to attract the attention of Dr.
James Deane, of Greenfield, that sagacious observer was struck with their
resemblance to the foot-marks left on the mud-banks of the adjacent river by
the aquatic birds which had recenty frequented the spot. The specimens
collected were submitted to Professor G. Hitchcock, who followed up the
inquiry with a zeal and success that have led to the most interesting
results. No reasonable doubt now exists that the imprints in question have
been produced by the tracks of bipeds impressed on the stone when in a soft
state. The announcement of this extraordinary phenomenon was first made by
Professor Hitchcock, in the 'American Journal of Science' (January, 1836),
and that eminent geologist has since published full descriptions of the
different species of imprints which he has detected, in his splendid work on
the geology of Massachusetts. -- Mantell's 'Medals of Creation', vol. ii.,
p. 310. In the work of Dr. Mantell above referred to, there is, in vol.
ii., p. 815, an admirable diagram of a slab from Turner's Falls, covered
with numerous foot-marks of birds, indicating the track of ten or twelve
individuals of different sizes.] -- Tr.
[footnote] **[From the examination of the fossils spoken of by geologists
under the name of 'Coprolites', it is easy to determine the nature of the
food of the animals, and some other points; and when, as happened
occasionally, the animal was killed while the process of digestion was going
on, the stomach and intestines being partly filled with half-digested food,
and exhibiting the coprolites actually 'in situ', we can make out with
certainty not only the true nature of the food, but the proportionate size
of the stomach, and the length and nature of the intestinal canal. Within
the cavity of the rib of an extinct animal, the palaeontologist thus finds
recorded, in indelible characters, some of those hieroglyphics upon which he
founds his history. -- 'The Ancient World', by
D. T. Ansted, 1847, p. 173.] -- Tr.
In the lower Jura formations (the lias of Lyme Regis), the ink bag of the
sepia has been so wonderfully preserved, that the material, which myriads
p 272
of years ago might have served the animal to conceal itself from its
enemies, still yields the color with which its image may be drawn.*
[footnote] *A discovery made by Miss Mary Anning, who was likewise the
discoverer of the coprolites of fish. These coprolites, and the excrements
of the Ichthyosauri, have been found in such abundance in England (as, for
instance, near Lyme Regis), that, according to Buckland's expression, they
lie like potatoes scattered in the ground. See Buckland, 'Geology
considered with reference to Natural Theology', vol. i., p. 188-202 and 305.
With respect to the hope expressed by Hooke "to raise a chronology" from
the mere study of broken and fossilized shells "and to state the interval of
time wherein such or such castrophes and mutations have happened," see his
'Posthumous Works, Lecture', Feb. 29, 1688.
[Still more wonderful is the preservation of the substance of the animal of
certain Cephalopodes in the Oxford clay. In some specimens recently
obtained, and described by Professor Owen, not only the ink bag, but the
muscular mantle, the head, and its crown of arms, are all preserved in
connection with the belemnite shell, while one specimen exhibits the large
eyes and the funnel of the animal, and the remains of two fins, in addition
to the shell and the ink bag. See Ansted's 'Ancient World', p. 147.] -- Tr.
In other strata, again, nothing remains but the faint impression of a muscle
shell; but even this, if it belong to a main dividion of mollusca,* may
serve to show the traveler, in some distant land, the nature of the rock in
which it is found, and the organic remains with which it is associated.
[footnote] *Leop. von Buch, in the 'Abhandlungen der Akad. der Wiss. zu
Berlin in dem Jahr' 1837, s. 64.
Its discovery gives the history of the country in which it occurs.
The analytic study of primitive animal and vegetable life has taken a double
direction: the one is purely morphological, and embraces, especially, the
natural history and physiology of organisms, filling up the chasms in the
series of still living species by the fossil structures of the primitive
world. The second is more specially geognostic, considering fossil remains
in their relations to the superposition and relative age of the sedimentary
formations. The former has long predominated over the latter, and an
imperfect and superficial comparison of fossil remains with existing species
has led to errors, which may still be traced in the extraordinary names
applied to certain natural bodies. It was sought to identify all fossil
species with those still extant in the same manner as, in the sixteenth
century, men were led by false analogies to compare the animals of the New
Continent with those of the Old. Peter Camper, Sommering, and Blumenbach
had the merit of being the first, by the scientific application of a more
accurate
p 273
comparative anatomy, to throw light on the osteological branch of
palaeontology -- the archaeology of organic life; but the actual geognostic
views of the doctrine of fossil remains, the felicitous combination of the
zoological character with the order of succession, and the relative ages of
strata, are due to the labors of George Cuvier and Alexander Brongniart.
The ancient sedimentary formations and those of transition rocks exhibit, in
the organic remains contained within them, a mixture of structures very
variously situated on the scale of progressively-developed organisms. These
strata contain but few plants, as, for instance, some species of Fuci,
Lycopodiaceae which were probably arborescent, Equisetaceae, and tropical
ferns; they present, however, a singular association of animal forms,
consisting of Crustacea (trilobites with reticulated eyes, and Calymene),
Brachiopoda ('Spirifer, Orthis'), elegant Sphaeronites, nearly allied to the
Crinoidea,* Orthoceraitites, of the family of the Cephalopoda, corals, and,
blended with these low organisms, fishes of the most singular forms,
imbedded in the upper silurian formations.
[footnote] *Leop. von Buch, 'Gebirgsformationen von Russland', 1840, s.
24-50.
The family of the Cephalaspides, whose fragments of the species 'Pterichtys'
were long held to be trilobites, belongs exclusively to the devonian period
(the old red), manifesting, according to Agassiz, as peculiar a type among
fishes as do the Ichthyosauri and Plesiosauri among reptiles.*
[footnote] *Agassiz, 'Monographie des Poissons Fossiles du vieux Gres
Rouge', p. vi. and 4.
The Goniatites, of the tribe of Ammonites,* a are manifested in the
transition chalk, in the graywacke of the devonian periods, and even in the
latest silurian formations.
[footnote] *Leop. von Buch, in the 'Abhandl. der Berl. Akad.', 1838, s.
149-168; Beyrich, 'Beitr. zur Kenntniss des Rheinischen Uebergangagebirges',
1837, s. 45.
The dependence of physiological gradation upon the age of the formations,
which has not hitherto been shown with perfect certainty in the case of
invertebrata,* is most regularly manifested in vertebrated animals.
[footnote] *Agassiz, 'Recherches sur les Poissons Fossiles', t. i.,
'Introd.', p. xviii.; Davy, 'Consolation in Travel', dial. iii.
The most ancient of these, as we have already seen, are fishes; next in the
order of succession of formation, passing from the lower to the upper, come
reptiles and mammalia. The first reptile (a Saurian, the Monitor of
Cuvier), which excited the attention of Leibnitz,* is found in cuperiferous
schist of the Zechstein of Thuringa; the Palaeosaurus and Thecodontosaurus
of Bristol are, according to Murchison, of the same age.
[footnote] *A Protosaurus, according to Hermann von Meyer. The rib of a
Saurian asserted to have been found in the mountain limestone (carbonate of
lime) of Northumberland (Herm. von Meyer, 'Palaeologica', s. 299), is
regarded by Lyell ('Geology', 1832, vol. i., p. 148) as very doubtful. The
discoverer himself referred it to the alluvial strata which cover the
mountain limestone.
The Saurians are found in large numbers in the muschelkalk,* in the keuper,
and in the oolitic formations, where they are the most numerous.
[footnote] *F. von Alberti, 'Monographie des Bunten Sandsteins,
Muschelkalks und Keupers', 1834, s. 119 und 314.
At the period of these formations there existed Pleiosauri, having long,
swan-like necks consisting of thirty vertebrae; Megalosauri, monsters
resembling the crocodile, forty-five feet in length, and having feet whose
bones were like those of terrestrial mammalia, eight species of large-eyed
Ichthyosauri, the Geosaurus or 'Lacerta gigantea', of Sommering, and
finally, seven remarkable species of Pterodactyles,* of Saurians furnished
with membranous wings.
[footnote] *See Hermann von Meyer's ingenious considertions regarding the
organization of the flying Saurians, in his 'Palaeologica', s. 228-252. In
the fossil specimen of the Pterodactylus crassirostris, which, as well as
the loonger known P. longirostris (Ornithocephalus of Sommering), was found
at Solenhofen, in the lithographic slate of the upper Jura formation,
Professor Goldfuss has even discovered traces of the membranous wing, "with
the impressions of curling tufts of hair, in some places a full inch in
length."
In the chalk the number of the crocodilial Saurians diminishes, although
this epoch is characterized by the so-called crocodile of Maestricht (the
Mososaurus of Conybeare), and the colossal, probably graminivorous Iguandon.
Cuvier has found animals belonging to the existing families of the
crocodile in the tertiary formation, and Scheuchzer's 'antediluvian man'
('homo diluvii testis'), a large salamander allied to the Axolotl, which I
brought with me from the large Mexican lakes, belongs to the most recent
fresh-water formations of Oeningen.*
[footnote] *[Ansted's 'Ancient World', p. 56.] -- Tr.
The determination of the relative ages of organisms by the superposition of
the strata has led to important results regarding the relations which have
been discovered between extinct families and species (the latter being but
few in number) and those which still exist. Ancient and modern observations
concur in showing that the fossil floras and faunas differ more from the
present vegetable and animal forms in proportion as they belong to lower,
that is, more ancient sedimentary formations. The numerical relations first
deduced by Cuvier
p 275
from the great phenomena of the metamorphism of organic life,* have led,
through the admirable labors of Deshayes and Lyell, to the most marked
results, especially with reference to the different groups of the tertiary
formations, which contain a considerable number of accurately investigated
structures.
[footnote] *Cuvier, 'Recherches sur les Ossemens Fossiles', t. i., p.
52-57. See, also, the geological scale of epochs in Phillips's 'Geology',
1837, p. 166-185.
Agassiz, who has examined 1700 species of fossil fishes, and who estimates
the number of living species which have either been described or are
preserved in museums at 8000, expressly says, in his masterly work, that,
"with the exception of a few small fossil fishes peculiar to the
argillaceous geodes of Greenland, he has not found any animal of this class
in all the transition, secondary or tertiary formations, which is
specifically identical with any still extant fish." He subjoins the
important observation "that in the lower tertiary formations, for instance,
in the coarse granular calcareous beds, and in the London clay,* one third
of the fossil fishes belong to wholly extinct families.
[footnote] *[See 'Wonders of Geology', vol. i., p. 230.] -- Tr.
Not a single species of a still extant family is to be found under the
chalk, while the remarkable family of the 'Sauroidi' (fishes with enameled
scales), almost allied to reptiles, and which are found from the coal beds
-- in which the larger species lie -- to the chalk, where they occur
individually, bear the same relation to the two families (the Lepidosteus
and Polypterus) which inhabit the American rivers and the Nile, as our
present elephants and tapirs do to the Mastodon and Anaplotheriun of the
primitive world."*
[footnote] *Agassiz, 'Poissons Fossiles', t. i., p. 30, and t. iii., p.
1-52; Buckland, 'Geology', vol. i., p. 273-277.
The beds of chalk which contain two of these sauroid fishes and gigantic
reptiles, and a whole extinct world of corals and muscles, have been proved
by Ehrenberg's beautiful discoveries to consist of microscopic Polythalamia,
many of which still exist in our seas, and in the middle latitudes of the
North Sea and Baltic. The first group of tertiary formations above the
chalk, which has been designated as belonging to the 'Eocene Period', does
not, therefore, merit that designation, since "the 'dawn of the world' in
which we live extends much further back in the history of the past than we
have hitherto supposed."*
[footnote] *Ehrenberg, 'Ueber noch jetzt lebende Thierarten der
Kreidelnldung', in the 'Abhandl. der Berliner Akad.', 1839, s. 164.
As we have already seen, fishes, which are the most ancient of all
vertebrata, are found in the silurian transition strata,
p 276
and then uninterruptedly on through all formations to the strata of the
tertiary period, while Saurians begin with the zechstone. In like manner,
we find the first mammalia ('Thylacotherium Prevostii', and 'T. Bucklandii',
which are nearly allied according to Valenciennes,* with marsupial animals)
in the oolitic formations (Stonesfield schist), and the first birds in the
most ancient cretaceous strata.**
[footnote] *Valenciennes, in the 'Comptes Rendus de l'Academie des
Sciences', t. vii., 1838, Part ii., p. 580.
[footnote] **In the Weald clay; Bendant, 'Geologie', p. 173. The
ornitholites increase in number in the gypsum of the tertiary formations.
Cuvier, 'Ossemens Fossiles', t. ii., p. 302-328.
Such are, according to the present state of our knowledge, the lowest*
limits of fishes, Saurians, mammalia, and birds.
[footnote] *[Recent collections from the southern hemisphere show that this
distribution was not so universal during the earlier epochs as has generally
been supposed. See papers by Darwin, Sharpe, Morris, and McCoy, in the
'Geological Journal'.] -- Tr'.
Although corals and Serpulidae occur in the most ancient formations
simultaneously with highly-developed Cephalopodes and Crustaceans, thus
exhibiting the most various orders grouped together, we yet discover very
determinate laws in the case of many individual groups of one and the same
orders. A single species of fossil, as Goniatites, Trilobites, or
Nummulites, sometimes constitutes whole mountains. Where different
families are blended together, a determinate succession of organisms has not
only been observed with reference to the superposition of the formations,
but the association of certain families and species has also been noticed in
the lower strata of the same formation. By his acute discovery of the
arrangement of the lobes of their chamber-sutures, Leopold von Buch has been
enabled to divide the innumerable quantity of Ammonites into
well-characterized families, and to show that Ceratites appertain to the
muschelkalk, Arietes to the lias, and Goniatites to transition limestone and
graywacke.*
[footnote] *Leop. von Buch, in the 'Abhandl. der Berl. Akad.', 1830, s.
135-187.
The lower limits of Belemnites are, in the keuper, covered by Jura
limestone, and their upper limits in the chalk formations.*
[footnote] *Quenstedt, 'Flotzgebirge Wurtembergs', 1843, s. 135.
It appears, from what we now know of this subject, that the waters must have
been inhabited at the same epoch, and in the most widely-remote districts of
the world, by shell-fish, which were at any rate, in part, identical with
the fossil remains found in England. Leopold von Buch has discovered
exogyra and trigonia in the southern hemisphere (volcano of
p 277
Maypo in Chili), and D'Orbigny has described Ammonites and Gryphites from
the Himalaya and the Indian plains of Cutch, these remains being identical
with those found in the old Jurassic sea of Germany and France.
The strata which are distinguished by definite kinds of petrifacations, or
by the fragments contained within them, form a geognostic horizon, by which
the inquirer may guide his steps, and arrive at certain conclusions
regarding the identity or relative age of the formations, the periodic
recurrence of certain strata, their parallelism, or their total suppression.
If certain strata, their parallelism, or their total suppression. If we
classify the type of the sedimentary structures in the simplest mode of
generalization, we arrive at the following series in proceeding from below
upward:
1. The so-called 'transition rocks', in the two divisions of upper and
lower graywacke (silurian and devonian systems), the latter being formerly
designated as old red sandstone.
2. The 'lower trias',* comprising mountain limestone, coal-measures,
together with the lower new red sandstone (Todtliegende and Zechstein).**
3. The 'upper trias', including variegated sandstone,** muschelkalk, and
keuper.
4. 'Jura limestone' (lias and oolite).
5. 'Green sandstone', the quader sanstein, upper and lower chalk,
terminating the secondary formations, which begin with limestone.
6. 'Tertiary formations' in three divisions, distinguished as granular
limestone, the lignites, and the sub-Apennine gravel of Italy.
[footnote] *Quenstedt, 'Flotzgebirge Wurtembergs', 1843, s. 13.
[footnote] ** Murchison makes two divisions of the 'bunter sandstone', the
upper being the same as the 'trias' of Alberti, while the lower division, to
which the 'Vosges sandstone' of Elie de Beaumont belongs -- the 'zeckstein'
and the 'todtliegende' -- he forms his 'Permian' system. He makes the
secondary formations commence with the 'upper trias', that is to say, with
the upper division of our (German) bunter sandstone, while the Permian
system, the carboniferous or mountain limestone, and the devonian and
silurian strata, constitute his 'palaeozoic formatiions'. According to
these views, the chalk and Jura constitute the upper, and the keuper, the
muschelkalk, and the bunter sandstone the lower secondary formations, while
the Permian system and the carboniferous limestone are the upper, and the
devonian and silurian strata are the lower palaeooic formation. The
fundamental principles of this general classification are developed in the
great work in which this indefatigable British geologist purposes to
describe the geology of a large part of Eastern Europe.
Then follow, in the alluvial beds, the colossal bones of the mammalia of the
primitive world, as the mastodon, dinothrium
p 278
missurium, and the megatherides, among which is Owen's sloth-like mylodon,
eleven feet in the length.*
[footnote] *[See Mantell's 'Wonders of Geology', vol. i., p. 168.] -- Tr.
Besides these extinct families, we find the fossil remains of still extant
animals, as the elephant, rhinoceros, ox, horse, and stag. The field near
Bogota, called the 'Campo de Gigantes', which is filled with the bones of
mastodons, and in which I caused excavations to be made, lies 8740 feet
above the level of the sea, while the osseous remains, found in the elevated
plateaux of Mexico, belong to true elephants of extinct species.*
[footnote] *Cuvier, 'Ossemens Fossiles', 1821, t. i., p. 157, 261, and 264.
See, also, Humboldt, 'Ueber die Hochebene von Bogota', in the 'Deutschen
Vierteljahrs-schrift', 1839, bd. i., s. 117.
The projecting spurs of the Himalaya, the Sewalik Hills, which have been so
zealously investigated by Captain Cantley* and Dr. Falconer, and the
Cordilleras, whose elevations are probably, of very different epochs,
contain, besides numerous mastodons, the sivatherium, and the gigantic land
tortoise of the primitive world ('Colossochelys'), which is twelve feet in
length and six in height, and several extant families, as elephants,
rhinoceroses, and giraffes; and it is a remarkable fact, that these remains
are found in a zone which still enjoys the same tropical climate which must
be supposed to have prevailed at the period of the mastodons.**
[footnote] *[The fossil fauna of the Sewalik range of hills, skirting the
southern base of the Himalaya, has proved more abundant in genera and
species of mammalia than that of any other region yet explored. As a
general expression of the leading features, it may be stated, that it
appears to have been composed of representative forms of all ages, from the
'oldest of the tertiary period down to the modern', and of 'all the
geographical' divisions of the Old Continent grouped together into one
comprehensive fauna. 'Fauna Antiqua Sivaliensis', by Hugh Falconer, M.D.,
and Major P. T. Cautley.] -- Tr.
Having thus passed in review both the inorganic formations of the earth's
crust and the animal remains which are contained within it, another branch
of the history of the organic life still remains for our consideration,
viz., the epoch of vegetation, and the successive floras that have occurred
simultaneously with the increasing extent of the dry land and the
modifications of the atmosphere. The oldest transition strata, as we have
already observed, contain merely cellular marine plants, and it is only in
the devonian system that a few cryptogamic forms of vascular plants
(Calamites and Lycopodiaceae) have been observed.*
[footnote] *Beyrich, in Karsteu's 'Archiv fur Mineralogie', 1844, bd.
xviii., s. 218.