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ON THE HISTORY

-/1-.

OF

EOZOON CANADENSE.

PAPERS BY

SIR W. E. LOGAN, F.R.S., F.G.S.
DR. J. W. DAWSON, P.R.S., F.G.S.
DR. W. B. CARPENTER, P.R.S., F.G.S.
DR. T. STERRY HUNT, F.R.S.

Jieprinted from Thb Quarterly Journal of the Gkological Socibtt
OF London for February 1865 (with additions) ; and from Thb
Canadian NATURALiST/or jlpril 1865.

WITH SIX WOOD ENGRAVINGS AND A LITHOGRAPHED

PLATE.

MONTREAL:

1866.

^'l

m

EOZOON CANADENSE.

On the Occurrence of Organic Remains in the Laurentian Rock»

of Canada.*

By Sir W. E. Looan, LL.D., F.R.S., F:G.S. ;
Director of the Geological Surrey of Canada.

The oldest known rocks of North America are those which com-
pose the Laurentide Mountains in Canada and the Adirondacks
in the State of New York. By the investigations of the Geological
Survey of Canada, they have been shown to be a great series of
strata, which, though profoundly altered, consist chiefly of quart-
zose, aluminous, and calcareous rocks, like the sedimentary de-
posits of less ancient times. This great mass of crystalline rocks
is divided into two groups, and it appears that the Upper rests
unconformably upon the Lower Laurentian series.

* This, and the three following papers, by Messrs. Dawson, Carpenter
and Sterry Hunt, are reprinted from the Quarterly Journal of the Geo-
logical Society of London, for February, 1865. Some additional notes
by the authors and editors are distinguished by being included in brack-
ets. See also a supplementary note by Dr. Dawsoj, on the discovery
of Eozoon in Ireland, on page 38.

In place of the lithographed plates published in the Quarterly Journal
to illustrate the papers uf Messrs. Dawson and Carpenter, selections from
those, filling a single plate, are here given ; btsides which three wood-
cuts are added. — Eds.

The united thickness of these two groups in Canada cannot be
less than 30,000 feet, and probably much exceeds it. The Lau-
rentian of the west of Scotland, according to Sir Roderick Mur-
chison, also attains a great thickness. In that region the Upper
Laurent ian or Labrador series, has not yet been separately recog-
nized ; but from Mr. McCuUoch's description, as well as from the
specimens collected by him, and now in the Museum of the Geolo-
gical Society of London, it can scarcely be doubted that the Labra-
dor series occurs in Skye.* The labradorite and hypersthene rocks
from that island are identical with those of the Labrador series in
Canada and New York, and unlike those of any formation at any
other known horizon. This resemblance did not escape the notice
of Emmons, who, in his description of the Adirondack Mountains,
referred these rocks to the hypersthene rock of McCulloch, although
these observers, on the opposite sides of the Atlantic, looked upon
them as unstratified. In the Canadian Naturalist for 1862,
Mr. Thomas Macfarlane, for some time resident in Norway, and
now in Canada, drew attention to the striking resemblance between
the Norwegian primitive gneiss formation, as described by Nau-
mann and Keilhau, and observed by himself, and the Laurentian,
including the Labrador group ; and the equally remarkable simi~
larity of the lower part of the primitive slate formation to the
Huronian series, which is a third Canadian group. These prim-
itive series attain a great thickness in the north of Europe, and
constitute the main features of Scandinavian geology.

In Bavaria and Bohemia there is an ancient gneissic series.
After the labours in Scotland, by which he was the first to estab-
lish a Laurentian equivalent in the British Isles, Sir Roderick
Murchison, turning his attention to this central European mass,
placed it on the same horizon. These rocks, underlying Barrande's
Primordial zone, with a great development of intervening clay-slate,
extend southward in breadth to the banks of the Danube, with a
prevailing dip towards the Silurian strata. They had previously

[• This was first shown by Mr. T. Sterry Hunt, after his examinations
of McGulloch's collections, in a paper published in the Dublin Quar.
Journal of Science for 1863, p. 230. See also Silliman's Journal [2]
xxxvi. 226, and Canadian Naturalist, vi. 208. Prof. Haughton of Dub-
lin has since visited the islands of Skye and lona, and confirmed the
observations of Mr. Hunt. See Proc, of the Royal Geological Society
of Dublin for Dec. 14, 1864, in the Geol. Magazine for February, 1865,
page 73.— Eds.]

been studied by Gumbcl and Crejci, who divided them into an
older reddish gneiss and a newer grey gneiss. But, on the Dan-
ube, the mass which is furthest removed from the Silurian rocks
being a grey gneiss, Giimbol and Crejci account for its presence by
an inverted fold in the strata ; while Sir Roderick places this at the
base, and regards the whole as a single series, in the normal funda-
mental position of the Laurentian of Scotland and of Canada. Con-
sidering the colossal thickness given to the series (90,000 feet), it
remains to bo seen whether it may not include both the Lower and
Upper Laurentian, and possibly, in addition, the Huronian.

This third Canadian group (the Huronian) has been shown by
my colleague, Mr. Murray, to be about 18,000 feet thick, and to
consist chiefly of quartzites, slate-conglomerates, diorites, and lime-
stones. The horizontal strata which form the base of the Lower
Silurian in western Canada, rest upon the upturned edges of the
Huronian series ; which, in its turn, unconformably overlies the
Lower Laurentian. The Huronian is believed to be more recent
tlian the Upper Laurentian series, although the two formations
have never yet been seen in contact.

The united thickness of these three great series may possibly far
surpass that of all the succeeding rocks from the base of the PaloBO-
zoic series to the present time. We are thus carried back to a
period so for remote, that the appearance of the so-called Prim-
ordial fauna may by some be considered a comparatively modern
event. We, howevek, find that, even during the Laurentian period,
the same chemical and mechanical processes which have ever since
been at work disintegrating and reconstructing the earth's crust
were in operation as now. In the conglomerate? -^f the Huronian
series there are enclosed boulders derived fro ■ '''^ Laurentian,
which seem to show that the parent rock was altd -i to its present
crystalline condition before the deposit of the newer formation ;
while interstratified with the Laurentian limestones there are beds
of conglomerate, the pebbles of which are themselves rolled frag-
ments of a still older laminated sand-rock, and the formation of
these beds leads us still further into the past.

In both the Upper and Lower Laurentian series there are seve-
ral zones of limestone, each of sufficient volume to constitute an
independent formation. Of these calcareous masses it has been
ascertained that three, at least, belong to the Lower Laurentian.
But as we do not as yet know with certainty either the base or
the summit of this series, these three may be conformably fol-

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lowed by many more. Although the Lower
and Upper Laurentian rooks spread over
more than 200,000 sqt ire miles in Canada,
only about 1500 square miles have yet been
fully and connectedly examined in any one
district, and it is still impossible to say
whether the numerous exposures of Lau-
rentian limestone met with in other parts
of the province are equivalent to any of the
three zones, or whether they overlie or un-
derlie them all.

Fig. 2. — Section aavss Trembling
Mountain (21 miles).

6. Upper Laurentian.

c. Fourth gneiss.
d\ Third limestone.

d. Third gneiss.

e'. Second limestone.

e. Second gneiss.

f. First limestone.
/. First gneiss.

In the examination of these ancient rocks,
the question often naturally occurred
to me whether, during these remote
periods, organic life had yet appeared on
the earth. The apparent abseuce of fossils
from the highly crystalline limestones did
not seem to ofiFer a proof in negation, any
more than their undiscovered presence in
newer crystalline limestones, where we have
little doubt they have been obliterated by
metamorphic action ; while the carbon
which, in the form of graphite, constitutes
beds, or is disseminated through the calca-
reous or siliceous strata of the Laurentian
series, seemed to be an evidence of the ex-
istence of vegetation, since no one disputes
the organic origin of this mineral in more
recent rocks. My colleague, Dr. T. Sterry

Hunt, has argued for the existence of organic matters at the
earth's surface during the Laurentian period from the presence
of great beds of iron-ore, and from the occurrence of metallic
8ulphurets * ; and finally, the evidence was strengthened by the
discovery of supposed organic forms. These were first brought
to me, in October, 1858, by Mr. J. McMullen, then attached as
an explorer, to the Geological Survey of the province, from cne
of the limestones of the Laurentian series occurring at the Grand
Calumet, on the River Ottawa.

Any organic remains which may have been entombed in these
limestones would, if they retained their calcareous character, be
almost certainly obliterated by crystallization ; and it would only
bo by the replacement of the original carbonate of lime by a
dificrent mineral substance, or by an infiltration of such a sub-
stance into all the pores and spaces in and about the fossil, that its
form would bo preserved. The specimens from the Grand Calu-
met present parallel or apparently concentric layers resembling those
of Stromatopora, except that they anastomose at various points.
What were first considered the layers are composed of crystallized
pyroxene, when the then supposed interstices consist of carbonate
of lime. These specimens, one of which is figured, in 'Geology
of Canada,' p. 49,f called to memory others which haf'. oome years
previously been obtained from Dr. James Wilson,' of Perth, and
were then regarded merely as minerals. They came, I be-
lieve, from masses in Burgess, but whether in place is not
quite certain; and they exhibit similar forms to those of the
Grand Calumet, composed of layers of a dark green magnesian sili-
cate (loganite) ; while what were taken for the interstices are filled
with crystalline dolomite. If the specimens from both these places
were to be regarded as the result of unaided mineral arrangement,
it appeared to me strange that identical forms should be derived
from minerals of such diflFerent composition. I was therefore dis-
posed to look upon them as fossils, and as such they were exhib-
ited by me at the meeting of the American Association for the
Advancement of Science, at Springfield, in August 1859. See
Canadian Naturalist, 1859, iv, 300. In 18G2 they were shown to
some of my geological friends in Great Britain ; but no micros-
copic structure having been observed belonging to them, few seemed
disposed to believe in their organic character, with the exception
of my friend Professor Ramsay.

* Quarterly Journal of the Geological Society, xv, 493.
[t Reproduced below, page 11, figures 1 and 2.]

8

It

•

One of tho specimens had been sliced and submitted to micro-
scopic observation, but unlbrtunatcly it was one of those composed
of loganite and dolomite. In these, the minute structure is rarely
seen. The true character of the specimens, thus remained in
suspense until last winter, when I accidentally observed indications
of similar forms in blocks of Laurentian limestone which had been
brought to our museum by Mr. James Lowe, one of our explorers,
to be sawn up for marble. In this case the forms were composed
of serpentine and ealc-apnr ; and slices of them having been pre-
pared for the microscope, the minute structure was observed in
the first one submitted to inspection. At the request of Mr.
Billings, the palaeontologist of our Survey, the specimens were
confided for examination and description to Dr. J. W. Dawson, of
Montreal, our most practised observer with the microscope ; and
the conclusions at which he has arrived are appended to this com-
munication, lie finds that the serpentine, which was supposed to
replace Ihc organic form, really fills the interspaces of the calca-
reous fossil. This exhibits in some parts a well-preserved organic
structure, which Dr. Dawson describes as that of a Foraminifer,
growing in large sessile patches after the manner of Polytrema and
Carpentaria^ but of much larger dimensions, and presenting
minute points which reveal a structure resembling that of other
Foraminiferal forms, as, for example, Caharina and Nummulina.

Dr. Dawson's description is accompanied by some remarks by
Dr. Sterry Hunt on the mincralogical relations of the fossil. He
observes that while the calcareous septa which form the skeleton of
the Foraminifer in general remain unchanged, the sarcode has
been replaced by certain silicates which have not only filled up the
chambers, cells, and septal orifices, but have been injected into the
minute tubuli, which are thus perfectly preserved, as may be seen
by removing the calcareous matter by an acid. The replacing
silicates are white pyroxene, serpentine, loganite, and pyrallolite or
rensselaerite. The pyroxene and serpentine are often found in
contact, filling contiguous chambers in the fossil, and were evi-
dently formed in consecutive stages of a continuous process. In
the Burgess specimens, while the sarcode is replaced by loganite,
the calcareous skeleton, as has already been stated, lias been re-
placed by dolomite, and the finer parts of the structure have been
almost wholly obliterated. But in the other specimens, where the
skeleton still preserves its calcareous character, the resemblance
between the mode of preservation of the ancient Laurentian For-

9

aminifcra and that of tho allied furins in Tertiary and recent
deposits (which, as Ehrenberg, Builcy, and Tourtales have shown,
arc injected with glauconito), is obvious.

Tho Grenville specimens belong to the highest of tho three
already mentioned zones of Laurcntiun limestone, and it lias not
yet been ascertained whether the fossil extends to the two confor-
mable lower ones, or to tho calcareous zones of the overlying un-
conformable Upper Laurentian scries. It lias not yet either been
determined what relation the strata from which the Burgess and
Grand Calumet specimens have been obtained bear to the Gren-
ville limestone or to one another. Tho zone of Grenville limestone
is in some places about 1500 feet thick, and it appears to be divi-
ded for considerable distances into two or three parts by very thick
bands of gneiss. One of these occupies a position towards the
lower part of tho limestone, and may have a volume of between
100 and 200 feet. It is at the base of the limestone that the fossil
occurs. This part of the zone is largely composed of great and
small irregular masses of white crystalline pyroxene, some of them
twenty yards in length by four or five wide. They appear to be
confusedly placed ono above another, with many ragged interstices,
and smoothly-worn, rounded largo and small pits and sub-cylindri-
cal cavities, some of them pretty deep. The pyroxene, though it
appears compact, presents a multitude of small spaces consisting of
carbonate of lime, and many of these show minute structures similar
to that of the fossil. These masses of pyroxene may characterize a
thickness of about 200 feet, and tin* interspaces among them are filled
■with a mixture of serpentine and carbonate of lime. In general a
sheet of pure dark green serpentine invests each mass of pyroxene ;
the thickness of the serpentine, varying from the sixteenth of an
inch to several inches, rarely exceeding half a foot. This is fol-
lowed in different spots by parallel, waving, irregularly alternating
plates of carbonate of lime and serpentine, which become gradually
finer as they recede from the pyroxene, and occasionally occupy a
total thickness of five or six inches. These portions constitute the
unbroken fossil, which may sometimes spread over an area of
about a square foot, or perhaps more. Other parts, immediately
on the outside of the sheet of serpentine, are occupied with about
the same thickness of what appear to be the ruins of the fossil,
broken up into a more or less granular mixture of calospar and
serpentine, the former still showing minute structure ; and on the
outside of the whole a similar mixture appears to have been swept

!|'l

10

i;'

!'i

I,.- 1

by currents and eddies into rudely parallel and curving layers; the
mixture becoming gradually more calcareous as it recedes from the
pyroxene. Sometimes beds of limestone ("sryeral feet in thick-
ness, with the green serpentine more or less aggregated intp layers,
and studded with isolated lumps of pyroxene, are irregularly in-
terstratified- in the mass of rock ; and less frequently there are met
with lenticular patches of sandstone or granular quartzite, of a
foot in thickness and several yards in diameter, holding in abun-
dance small disseminated leaves of graphite.

The general character of the rock connected with the fossil pro-
duces the impression that it is a great Foramini'";ral reef, in
which the pyroxenic masses represent a more a: cient portion,
which having died, and having become much broken up and
worn into cavities and deep recesses, afford-^d a seat for a new
groy/th of Foramini/era, represented by the calcareo-serpentinous
part. This in its turn became broken up, leavir^ n some places
uninjured "-^rtions of the general form. The main difference be-
tween this Foraminiferal reef and more recent coral-reefs seems to
be that, while with the latter are usually associated many shells
and otiier organic remains, in the more ancient one the only
remains yet found are those of the ani .al which built the reef.

1

On Certain Organic Remarks in the 1 urent'um Limestones of

Canada.'^

By J. W.Dawson, LL.D <\R.S.,

Principal of McGill University, )ntre<'.l, Cunada.

n

At the request of Sir William E. Lo^... , I have submitted to
microscopic examination slices of certain peculiar laminated forms
consisting of alternate layers of carbonate of lime and serpentine,
or of carbonate of lime and white pyroxene, found in the Lauren-
tian limestones of Canada, and regarded by Sir William as possi-
bly fossils.f I have alpo examined slices of a number of lime-
stones and serpentines from the Laurentian series, not showing
the external forms of these supposed fossils.

The slices were prepared by the lapidary of the Survey, and
were carefully examined under ordinary and polarized light, with

[* See a preliminary notice in Silliman's Journal [2], xxxvii, 272.]
t Canadian Xaturalist, 1859, p. 300.

11

objectives made by Ross, and by Smith and Beck ; and also with good
French objectives.

1. Weathered specimen of Eozobn Canadense from the Calumet,
of the natural size. The replacing silicate is white pyroxene.

2. Vertital transverse section of the specimen figure 1.

The 8pecinr»ens first mentioned are masses, often several inches
in diameter, presenting to the naked eye alternate laminae of ser-
pentine, or of pyroxene, and carbonate of lime. Their general as-
pect, as remarked by Sir W. E. Logan (Geology of Canada, 1863,
p. 49), reminds the observer of that of the Silurian corals of the
genus Stromatopora, except that the laminae diverge from and
approach each other, and frequently anastomose or are connected
by transverse septa.

12

w

If

M

Under the uiicroscopo the resemblance to Stromatopora is seen
to be in general form merely, and no trace appears of the radiating
. cells characteristic of that genus. The laminae of serpentine and
pyroxene present no organic structure, and the latter mineral is
highly crystalline. The laminae of carbonate of lime, on the con-
trary, retain distinct traces of structures which cannot be of a
crystalline or concretionary character. They constitute parallel or
concentric partitions of variable thickness, enclosing flattened spaces
or chambers, frequently crossed by transverse plates or septa, in
some places so numerous as to give a vesicular appearance, in others
occurring only at rare intervals (figure 3). The lamina) them-
selves are excavated on their sides into rounded pits, and
are in some places traversed by canals, or contain secondary
rounded cells, apparently isolated. In addition to these general
appearances, the substance of the laminae, where most perfectly
preserved, is seen to present a fine granular structure,
and to be penetrated by numerous minute tubuli, which are
arranged in bundles of great beauty and complexity, diverging in
sheaf-like forms, and in their finer extensions anastomosing so as
to form a net-work (plate, figures 2 and 4). In transverse sections,
and under high powers, the tubuli are seen to be circular in outline,
and sharply defined (plate, figure 5). In longitudinal sections,
they sometimes present a beaded or jointed appearance. Even
Avhere the tubular structure is least perfectly preserved, traces of
it can still be seen in most of the slices, though there are places
in which the laminae are perfectly compact, and perhaps were so
originally.

Faithful delineations of these structures have been prepared by
Mr. Horace Smith, the artist of the Survey, which will render them
more intelligible than any verbal description.

With respect to the nature and probable origin of the appearances
above described, I would make the following remarks :

1. The serpentine and pyroxene which fill the cavities of the cal-
careous matter have no appearance of concretionary structure. On
the contrary, their aspect is that of matter introduced by infiltra-
tion, or as sediment, and filling spaces previously existing. In
other words, the calcareous matter has not been moulded on the
forms of the serpentine and augite, but these have filled spaces or
chambers in a hard calcareous mass. This conclusion is further
confirmed by the fact, to be referred to in the sequel, that the ser-
pentine includes multitudes of minute foreign bodies, while the

•i

13

iating

calcareous matter is uniform and homogeneous. It is also to be
observed that small veins of carbonate of lime occasionally traverse
the specimens, and in their entire absence of structures other than
crystalline, present a striking contrast to the supposed fossils.
2. Though the calcareous laminae have in places a crystalline

3. Nature-printed section of a specimen of Eozodn Canadense from
Petite Nation Seigniory.*

[* The replacing mineral in this specimen being serpentine, the cal-
careous septa were dissolved from the polished surface by the action of
an acid, and the iiiiu material replacing the tubuli having been removed by
the aid of a brush, a wax mould of the etched surface furnished the
electrotype cast from which the above figure is printed. The lights
thus represent the calcareous skeleton, and the shaded portion a thick
massof3erpentine,which is distinguishable from a contiguous thin stratum
of the same mineral, that seems to form the base of the Eozodn. The
gradual passage from the wide chambers and thick septa to the nar-
rower and thinner ones, and finally to the irregularly aggregated mode
of growth, designated by Dr. Carpenter as acervulinv, is well seen.
The white patches in the upper portion of the figure do not arise from
any imperfection in the electrotype, but represent the irregular growth
of this part of the calcareous skeleton.— T. S. H,]

«^

14

ijl

cleavage, their forms and structures have no relation to this. Their
cells and canals are rounded, and have smooth walls, which are
occasionally lined with films apparently of carbonaceous matter.
Above all, the minute tubuli are different from anything likely to
occur in merely crystalline calcspar. While in such rocks little
importance might be attached to external forms simulating the
appearances of corals, sponges, or other organisms, these delicate
internal structures have a much higher claim to attention. Nor is
there any improbability in the preservation of such minute parts
in rocks so highly crystalline, since it is a circumstance of frequent
occurrence in the microscopic examination of fossils that the finest
structures are visible in specimens in which the general form and
the arrangement of parts hav' been entirely obliterated. It is also
to be observed that the struct e of the calcareous laminaD is the
same, whether the intervening spaces are filled with serpentine or
with pyroxene.

3. The structures above described are not merely definite and
uniform, but they are of a kind proper tu uuimal organisms, and
more especially to one particular type of animal life, as likely as
any other to occur under such circumstances ; I refer to that of
the Rhizopods of the order Foramini/era. The most important
point of difference is in the great size and compact habit of growth
of the specimens in question ; but there seems no good reason to
maintain that Foramini/era must necessarily be of small size, more
especially since forms of considerable magnitude referred to this
type are known in the Lower Silurian. Prof. Hall has described
specimens of Receptaculitcs twelve inches in diameter ; and the
fossils from the Potsdam formation of Labrador, referred by Mr.
Billings to the genus Archoeocyathus, are examples of Protozoa with
calcareous skeletons scarcely inferior in their massive style of
growth to the forms now under consideration.*

[• The following note is inserted in place of another, which, by an
error of the printer, is in the Quarterly Journal of the Geological
Society inccrporated with the text :

Mr. Billinijs has ascertained, since this paper was written, that one of
the species included in the genus ^rchceocyathun, has silicious spicula
which would place it with the sponges. But two other species of the
genus have, in accordance with his original description, a chambered
calcareous skeleton, which is, in my opinlun, similar to that of Foramin-
ifera. (Memoirs of the Geological Survey of Canada, Nov. 1861, and
reprint of the same in 1864.)— J. W. D.]

15

These reasons arc, I think, sufficient to justify me in regarding
these remarkable structures as truly organic, and in searching for
their nearest allies among the Foramini/era.

Supposing then that the spaces between the calcareous laminae,
as well as the canals and tubuli traversing their substance, were
once filled with the sarcode body of a Rhizopod, comparisons with
modern forms at once suggest themselves.

From the polished specimens in the Museum of the Canadian
Geological Survey, it appears certain that these bodies were sessile
by a broad base, and grew by the addition of successive layers
of chambers separated by calcareous laminae, but communicating
with each other by canals or septal orifices sparsely and irregularly
distributed. Small specimens have thus much the aspect of the
modern genera Carpenteria and Polytrema. Like the first of
these genera, there would also seem to have been a tendency to
leave in the midst of the structure a large central canal, or deep
funnel-shaped or cylindrical opening, for communication with the
sea-water. Where the laminae coalesce, and the structure becomes
more vesicular, it assumes the ' acervuline' character seen in such
modern forms as Nubecularia.

Still the magnitude of these fossils is enormous when compared
with the species of the genera above named ; and from the speci-
mens in the larger slabs from Grenville, in the Museum of the
Canadian Survey, it would seem that these organisms grew in
groups, which ultimately coalesced, and formed large masses pene-
trated by deep irregular canals ; and that they continued to grow
at the surface, while the lower parts became dead and were filled
up with infiltrated matter or sediment. In short, we have to
imagine an organism having the habit of growth of Carpenteria,
but attaining to an enormous size, and by the aggregation of indi-
viduals assuming the aspect of a coral reef

The complicated systems of tubuli in the Laurentian fossil
indicate, however, a more complex structure than that ol any of
the forms mentioned above. I have carefully compared these with
the similar structures in the ' supplementary skeleton' (or the
shell-substance that carries the var^cular system) of Calcarina and
other forms,* and can detect no difiierence except in the somewhat

♦ I desire to express my obligations to the invaluable memoirs of Dr.
Carpenter on the Foraminifera, in the Transactions of the Royal
Society, and in the publications of the Ray Society ; without which

16

it

coarser texture of the tubuli in the Laurentian specimens. It
accords well with the great dimensions of those, that they should
thus thicken their walls with an extensive deposit of tubulated cal-
careous matter ; and from the frequency of the bundles of tubuli,
as well as from the thickness of the partitions, I have no doubt that
all the successive walls, as they were formed, were thickened in this
manner, just as in so many of the higher genera of more modern
Foraminifera.

It is proper to add that no spicules, or other structures indica-
ting affinity to the Sponges, have been detected in any of tlie
specimens.

As it is convenient to have a name to designate these forms,^
I would propose that of Eozodn, which will be specially appropriate
to what seems to be the characteristic fossil of a group of rocks
which must now be named Eozoic rather than Azoic. For the
species above described, the specific name of Canadense has been
proposed. It may be distinguished by the following characters : —

EozoiiN Canadense; gen. et spec. nov.

General form. — Massive, in large sessile patches or irregular
cylinders, growing at the surface by the addition of successive
laminsc.

Internal structure. — Chambers large, flattened, irregular, with
numerous rounded extensions, and separated by walls of variable
thickness, which are penetrated by septal orifices irregularly
disposed. Thicker parts of the walls with bundles of fine branch-
ing tubuli.

'i^

I

i:

These characters refer specially to the specimens from Grenville
and the Calumet. There are others from Perth, C. W.,
which show more regular lamina9, and in which the tubuli have
not yet been observed ; and a specimen from Burgess, C. W.,
contains some fragments of laminae which exhibit, on one side,
a series of fine parallel tubuli like those of Nummulina. These
specimens may indicate distinct species ; but on the other hand,
their peculiarities may depend on different states of preservation.

With respect to this last point, it may be remarked that some of

it would have been impossible satisfactorily to investigate the structure
and affinities of Eozotin. I have also to acknowledge the kindness of
Dr. Carpenter in furnishing me with specimens of some of the forms
described in his works.

17

the specimens from Grenville and the Calumet show the structures
of the laminae with nearly equal distinctness whether the chambers
have been filled with serpentine or pyroxene, and that even the
minute tubuli are penetrated and filled with these minerals. On
the other hand, there are large specimens in the collection of the
Canadian Survey, in which the lower and older parts of the masses
of Eozoon are mineralized with pyroxene, and have to a great
extent lost the perfection of structure which characterizes the more
superficial parts of the same masses, in which the chambers have
been filled with a light green serpentine. Dr. Sterry Hunt has
directed his attention to the conditions of deposit of these minerals,
and will, I have no doubt, be able satisfactorily to explain the
manner in which they may have been introduced into the chambers
of the fossils without destroying the texture of the latter.

It is due to Dr. Sterry Hunt to state that, as far back as 1858,
in a paper published in the Quarterly Journal of the Geological
Society,* he insisted on certain chemical characters of the Lauren-
tian beds as affording " evidence of the existence of organic life
at the time of the deposition of these old crystalline rocks"; and
that he has zealously aided in the present researches.

I may also state that Mr. Billings, the palaeontologist of the
Survey, has joined in the request that I should undertake the
examination and description of the specimens, as being more
specially a subject of microscopical investigation.

Before concluding this part of the subject, it is proper to
observe that the structures above described can be made out only
by the careful study of numerous slices, and in some instances
only with polarized light. Even in the more perfect specimens of
Eozoon J as those accustomed to such researches will readily under-
stand, the accidents of good preservation and the cutting of the
slices in the proper place and direction must conspire in order to
a clear definition of the more minute structures.

It is also to be observed that the specimens present numerous
remarkable microscopic appearances, depending on crystallization
and concretionfiry action, which must not be confounded with
organic structure. It would be out of place to give any detailed
description of them here ; but it is necessary to caution observers
unaccustomed to the examination of mineral substances under the
microscope, as to their occurrence. I may also mention that the

• Vol. xr, p. 493.
B

18

;M

serpentine presents many curious varieties of structure, especially
when associuted with apatite, pyroxene, and other minerals, and
that it affords magnificent objects under polarized light, when
reduced to sufficiently thin slices.

In connexion with these remarkable remains, it appeared desir-
able to ascertain, if possible, what share these or other organic
structures may have had in the accumulation of the limestones
of the Laurentian series. Specimens were therefore selected by
Sir W. E. Logan, and slices were prepared under his direction.
On microscopic examination, a number of these were found to
exhibit merely a granular aggregation of crystals, occasionally with
particles of graphite and other foreign minerals ; or a laminated
mixture of calcareous and other matters, in the manner of some
more modern sedimentary limestones. Others, however, were
evidently made up almost entirely of fragments of Eozoon, or of
mixtures of these with other calcareous and carbonaceous fragments
which afford more or less evidence of organic origin. The contents
of these organic limestones may be considered under the following
heads : —

1. Remains o{ Eozoon.

2. Other calcareous bodies, probably organic.

3. Objects imbedded in the serpentine.

4. Carbonaceous matters.

5. Perforations, or worm-burrows.

1. The more perfect specimens of Eozoon do not constitute the
mass of any of the larger specimens in the collection of the
Survey ; but considerable portions of some of them are made up
of material of similar minute structure, destitute of lamination,
and irregularly arranged. Some of this material gives the impression
that there may have been organisms similar to Eozoon^ but growing
in an irregular or acervuline manner without lamination. Of
this, however, I cannot be certain ; and on the other hand there is
distinct evidence of the aggregation of fragments of Eozoon in
some of these specimens. In some they constitute the greater part
of the mass. In others they are imbedded in calcareous matter
of a different character, or in serpentine or granular pyroxene. In
most of the specimens the cells of the fossils are more or less filled
with these minerals ; and in some instances it would appear that
the calcareous matter of fragments of Eozoon has been in part
replaced by serpentine.

%

19

jcxer, were

2. Intermixed with the fragments of Eozoon above referred to
are other calcareous matters apparently fragmentary. They are
of various angular and rounded forms, and present several kinds
of structure. The most frequent of these is a strong lamination,
varying in direction according to the position of the fragments,
but corresponding, as far as can be ascertained, with the diagonal
of the rhombohedral cleavage. This structure, though crystalline,
is highly characteristic of crinoidal remains when preserved in
altered limestones. The more dense parts of Eozoon, destitute of
tubuli, also sometimes show this structure, though less distinctly.

Other fragments are compact and structureless, or show only a
fine granular appearance; and these sometimes include grains,
patches, or fibres of graphite. In Silurian limestones, fragments
of corals and shells which have been partially infiltrated with
bituminous matter show a structure like this. On comparison with
altered organic limestones of the Silurian system, these appearances
would indicate that, in addition to the debris of Eozoon, other
calcareous structures, more like those of crinoids, corals, and
shells, have contributed to the formation of the Laurentiaa
limestones.

3. In the serpentine* filling the chambers of a large specimen
of Eozoon from Burgess, there are numerous small pieces of
foreign matter; and the silicate itself is laminated, indicating
its sedimentary nature. Some of the included fragments appear
to be carbonaceous, others calcareous; but no distinct organic
structure can be detected in them. There are however in the
serpentine many minute rounded siliceous grains of a bright green
color, resembling green-sand concretions ; and the manner in which
these are occasionally arranged in lines and groups suggests the
supposition that they may possibly be casts of the interior of
minute Foraminiferal shells. They may however be concretionary
in their origin.

4. In some of the Laurentian limestones submitted to me by
Sir W. E. Logan, and in others which I collected some years ago
at Madoc, Canada West, there are fibres and granules of carbon-
aceous matter, which do not conform to the crystalline structure,
and present forms quite similar to those which in more modern
limestones result from the decomposition of algae. Though retain-
ing mere traces of organic structure, no doubt would be entertained

[* This is the dark green mineral named logaaite by Dr. Hunt.]

20

'I, I

l:li

iljl

as to their vegetable origin if they were found in fossiliforous
limestones.

5. A specimen of impure limestone from Madoo, in the collection
of the Canadian Geological Survey, which seems from its structure
to have been a finely laminated sediment, shows perforations of
various sizes, somewhat scalloped at the sides, and filled with grains
of rounded siliceous sand. In my own collection there are specimens
of micaceous slate from the same region, with indications on their
weathered surfaces of similar rounded perforations, having the
aspect of Scolithus, or of worm-burrows.

I would observe, in conclusion, that the observations detailed in
this paper must be regarded as merely an introduction to a most
interesting and promising field of research. The specimens to
which I had access were for the most part collected by the explorers
of the Survey merely as rocks, and without any view to the possible
existence of fossils in them. It may bo hoped, therefore, that
other and more perfect specimens may reward a careful search in
the localities from which those now described have been obtained.

Further, though the abundance and wide distribution of Eozoon,
and the important part it seems to have acted in the accumulation
of limestone, indicate that it was one of the most prevalent forms
of animal existence in the seas of the Laurentian period, the
non-existence of other organic beings is not implied. On the
contrary, independently of the indications afforded by the
limestones themselves, it is evident that in order to the existence
and growth of these large Rhizopods, the waters must have
swarmed with more minute animal or vegetable organisms on which
they could subsist. On the other hand, though this is a less certain
inference, the dense calcareous skeleton of Eozo'On may indicate
that it also was liable to the attacks of animal enemies. It is also
possible that the growth of Eozoon, or the deposition of the
serpentine and pyroxene in which its remains have been preserved,
or both, may have been connected with certain oceanic depths and
conditions, and that we have as yet revealed to us the life of only
certain stations in the Laurentian seas. Whatever conjectures we
may form on these more problematic points, the observations above
detailed appear to establish the following conclusions : — First, that
in the Laurentian period, as in subsequent geological epochs, the
Bhizopods were important agents in the accumulation of beds of
limestone ; and secondly, that in this early period these low forms
of animal life attained to a development, in point of magnitude

21

bssiliforous

0 collection
ts structure
forations of
with grains
re spccimenti
3ns on their

detailed in
n to a most
pccimens to
;he explorers
) the possible
erefore, that
ill search in
len obtained,
n of Eozoon,
Accumulation
svalent forms
I period, the
ed. On the
ded by the
the existence
; must have
sms on which
a less certain
may indicate
s. It is also
ition of the
en preserved,
ic depths and
! life of only
onjectures we
vations above
; — First, that
il epochs, the
)n of beds of
ese low forms
Df magnitude

and complexity, unexampled, in so far as yet known, in the succeed-
ing ages of the earth's history. This early culmination of the
Khizopods is in accordance with one of the great laws of the
succession of living beings ascertained from the study of the
introduction and progress of other groups ; and, should it prove
that these great Protozoans were really the dominant type of
animals in the Laurentian period, this fact might be regarded as
an indication that in these ancient rocks we may actually have the
records of the first appearance of animal life on our planet.

Since the above was written, thick slices of Eozoon from Oren-
ville have been prepared, and submitted to the action of hydrochloric
acid until the carbonate of lime was removed. The serpentine then
remains as a cust of the interior of the chambers, showing the
form of their original sarcoJo-contents. The minute tubuli are
found also to have been filled with a substance insoluble in the
acid, so that casts of these also remain in great perfection, and
allow their general distribution to bo much better seen than in the
transparent slices previously prepared. These interesting prepara-
tions establish the following additional structural points :

1. That the whole mass of sarcode throughout the organism was
continuous ; the apparently detached secondary chambers being, as
I had previously suspected, connected with the larger chambers
by canals filled with sarcode.

2. That some of the irregular portions without lamination are
not fragmentary, but due to the acervuliue growth of the animal j
and that this irregularity has been produced in part by the formation
of projecting patches of supplementary skeleton, penetrated by
beautiful systems of tubuli. These groups of tubuli are in some
places very regular, and have in their axes cylinders of compact
calcareous matter. Some parts of the specimens present arrange-
ments of this kind as symmetrical as in any modern Forarainiferal
shell

3. That all except the very "thinnest portions of the walls of the
chambers present traces, more or less distinct, of a tubular
structure.

4. These facts place in more strong contrast the structure of the
regularly laminated specimens from Burgess, which do not show
tubuli, and that of the Grenville specimens, less regularly laminated
and tubulous throughout. I hesita o owever to regard these two
as distinct species, in copscquence of the intermediate characters

22

presented by specimens from the Calumet, which are rogularlj
laminated like those of Burgess, and tubulous like those of Oron-
ville. It is possible that in the Burgess specimens tubuli originally
present have been obliterated ; and in organisms of this grade>
more or less altered by the processes of fossilization, large series
of specimens should bo compared before attempting to establish
specific distinctions.

Some additional specimens, from a block consisting principally of
serpentine, diflFer from the ordinary Grenville specimens in the
more highly crystalline character of the calc-spar and ser-
pentine, in the development of certain minute dendritic crys-
tallizations, and in the apparent compression and distortion of the
fossils. These appearances I regard as duo to the mode of
preservation, rather than to any original differences; certain
portions less altered than the others presenting the ordinary typical
characters.

Two slices of limestone from the British Islands, and supposed
to be Laurentian, liave been compared with the Canadian lime-
stones above noticed. One is a serpentine-marble from Tyree. It
appears to be fragmental like some of the Laurentian limestones
of Canada, and may contain fragments of Eozoon. The other is
from Ireland,* and presents what I regard as traces of organic
structure, but not, in so far as can be made out, of the character
oi Eozo'un. Both of these limestones deserve careful microscopic
examination.

Notes on the Structure and AJinities of Eozoon Canadense.

By W. B. Carpenter, M.D., F.R.S., F.G.S.
[la a Letter to Sir William E. Logan, LL.D , F.R.S., F.G.S.]

The careful examination which I have made — in accordance
with the request you were good enough to convey to mo from Dr.
Dawson, and to second on your own part — into the structure of

[• Given by mistake as " lona" in the Journal of the Geological Society.
It is a specimen of Connemara marble from the collection of Dr. Hunt,
who supposed it to be Laurentian. See note on page 4, and for
further observations on this marble see below, page 38.]

23

the very extraordinary fossil winch you have brought from the
Laurontian rocks of Cuna«]:i,* enables iiio most unhesitatingly to
confirm the sagaciou." rlotcrmiii/ition of Dr. Dawsou us to its Ilhi-
zopod characters and 1 . iininiferal affinities, and at the eamo
time furnishes ne\«' <'videnco ni r»o small value in support of that
determination. In thi^ fxnniinatiun I Imvc had the advantage of
a series of sections of the ioisil much superior to those submitted
to Dr. Dawson ; and also of a largo scries of decalcified specimens,
of which Dr. Dawson had only the opportunity of seeing a few ex-
amples after his memoir had been written. These last are pecu-
iarly instructive ; since in consequence of the complete infiltration
of the chambers and canals, originally occupied by the sarcodc-
body of the animal, by mineral matter insoluble in dilute nitric
acid, the removal of the calcareous shell brings into view not only
the internal casts of the chambers, but also casts of the interior of
the ' canal-system ' of the ' intermediate' or ' supplemental skele-
ton,' and even casts of the interior of the very fine parallel tubuli
which traverse the proper walls of the chambers. And, as I have
remarked elsewherc,f " such casts place before us far more exact
representations of the configuration of the animal body, and of the
connexions of its different parts, than wo could obtain even from
living specimens by dissolving away their shells with acid; its
several portions being disposed to heap themselves together ia a
mass when they lose the support of the calcareous skeleton."

The additional opportunities I have thus enjoyed will be found,
I believe, to account satisfactorily for the differences to be observed
between Dr. Dawson's account of the Eozoon and my own. Had
I been obliged to form my conclusions respecting its structure
only from the specimens submitted to Dr. Dawson, I sliould very
probably have seen no reason for any but the most complete
accordance with his description : while if Dr. Dawson had
enjoyed the advantage of examining the entire series of prepara-
tions which have come under my own observation, I feel confident
that he would have anticipated the corrections and additions which
I now ofiFer.

* The specimens submitted to Dr. Carpenter were talien from a block
of Eozoon rock, obtained in the Petite Nation Seigniory, too late to afford
Dr. Dawson an opportunity of examination. They are from the same
horizon as the Grcnville specimens. — W. E. L.

t Introduction to the Study of the Foraminifera, p. 10.

u

if

nj'-i

Although the general plan of growth described by Dr. Dawson,
and exhibited in his photographs of vertical sections of the fossil,
is undoubtedly that which is typical of Eozoon, yet I find that the
acervuline mode of growth, also mentioned by Dr. Dawson, very
frequently takes its place in the more superficial parts, where the
chambers, which are arranged in regular tiers in the laminated
portions, are heaped one upon another without any regularity, as is
particularly well shown in some decalcified specimens which I have
myself prepared from the slices last put into my hands. I see no
indication that this departure from the normal type of structure
has resulted from an injury ; the transition from the regular to the
irregular mode of increase not being abrupt, but gradual. Nor
should I be disposed to regard it as a monstrosity ; since there are

4. Diagram illusthatino the structure of Eozoon.

A', A', A'. Three chambers of one layer, communicating with each other
directly- at a, and by three passages through a shelly par-
tition at b.

A^, A^, A^. Three chambers of a more superficial layer.

B, B, B. Proper wall of the chambers, composed of finely tubular ehell-

substance.

C, C, C. Intermediate or supplemental skeleton, traversed by D, a

stolon of communication between two chambers of different
layers, and by E, E, a canal-system originating in the lacu-
nar space F.

many other Foramini/era in which an originally definite plan of
growth gives place, ia a later stage, to a like acervuline piling-up of
chambers.
In regard to the form and relations of the chambers, I havp little

25

jular ehell-

to add to Dr. Dawson's description. The evidence afiForded by
their internal casts concurs with that of sections, in showing that
the segments of the sarcode-body, by whose aggregation each layer
was constituted, were br very incompletely divided by shelly par-
titions ; this incomplete separation (as Dr. Dawson has pointed out)
having its parallel in that of the secondary chambers in Carpen-
teria. But I have occasionally met with instances in which the
separation of the chambers has been as complete as it is in Foramin-
ifera generally ; and the communication between them is then
established by several narrow passages exactly corresponding
with those which I have described and figured in Cydoclypeiis.^
The mode in which each successive layer originates from the
one which had preceded it, is a question to which my attention
has been a good deal directed ; but I do not as yet feel confident
that I have been able to elucidate it completely. There is certainly
no regular system of apertures for the passage of stolons giving
origin to new segments, such as are found in all ordinary Polytha-
lamous Foraminifera, whether their type of growth be rectilinear,
spiral, or cyclical ; and I am disposed to believe that where one
layer is separated from another by nothing else than the proper
walls of the chambers, — which, as I shall presently show, are tra-
versed by multitudes of minute tubuli giving passage to pseudo-
podia, — the coalescence of these pseudopodia on the external surface
would sufiice to lay the foundation of a new layer of sarcodic seg-
ments. But where an intermediate or supplemental skeleton, con-
sisting of a thick layer of .solid calcareous shell, has been deposited
between two successive layers, it is obviois that the animal body
contained in the lower layer of chambers must be completely cut
oflF from that which occupies the upper, unless some special pro-
vision exist for their mutual communication. Such a provision I
believe to have been made by the extension of bands of sarcode,^
through canals left in the intermediate skeleton, from the lower to
the upper tier of chambers. For in such sections as happen to
have traversed thick deposits of the intermediate skeleton, there
are generally found passages distinguished from those of the ordi-
dary canal-system by their broad flut form, their great trans-
verse diameter, and their non-ramification. One of these passages
I have distinctly traced to a chamber, with the cavity of which it
communicated through two or three apertures in its proper wall

* Op. cit., p. 294.

26

I

'I

(plate, figure 3. c) ; and I think it likely that I should have
been able to trace it at its other extremity into a chamber of the
superjacent tier, had not the plane of the section passed out of its
course. Riband-like casts of these passages are often to be seen
in decalcified specimens, traversing the void spaces left by the re-
moval of the thickest layers of the intermediate skeleton.

But the organization of a new layer seems to have not unfre-
quently taken place in a much more considerable extension of the
sarcode-body of the pre-formed layer ; which either folded back its
margin over the surface already consolidated, in a manner somewhat
like that in which the mantle of a Cyproea doubles back to deposit
the final surface-layer of its shell, or sent upwards wall-like la-
mellae, sometimes of very limited extent, but not unfrequently of
considerable length, which, after traversing the substance of the
shell, like trap-dykes in a bed of sandstone, spread themselves out
over its surface. Such, at least, are the only interpretations I can
put upon the appearances presented by decalcified specimens. For
on the one hand, it is frequently to be observed that two bands of
serpentine (or other infiltrated mineral), which represent two layers
of the original sarcode-body of the animal, approximate to each other
in some part of their course, and come into complete continuity ; so
that the upper layer would seem at that part to have had its origin
in the lower. Again, even where these bands are most widely sepa-
rated, we find that they are commonly held together by vertical
lamellae of the same material, sometimes forming mere tongues, but
often running to a considerable length. That these lamelleD have
not been formed by mineral infiltration into accidental fissures in
the shell, but represent corresponding extensions of the sarcode-
body, seems to me to be indicated not merely by the characters of
their surface, but also by the fact that portions of the canal-system
may be occasionally traced into connection with them.

Although Dr. Dawson has noticed that some parts of the sections
which he examined present the fine tubulation characteristic of the
shells of the Nummuline Foraminifera, he does not seem to have
recognize^ the fact, which the sections placed in my hands have en-
abled me most satisfactorily to del ermine, — that the proper walls of
the chambers everywhere present the fine tubulation of the Nummu-
line shell (plate, figs. 3, 6) ; a point of the highest importance in
the determination of the aJKnities of Eozoon. This tubulation,
although not seen with the clearness with which it is to be discerned

27

in recent examples of the Nummuline type, is here far better dis-
played than it is in the majority of fossil Nummulites, in which the
tubuli have been filled up by the infiltration of calcareous matter,
rendering the shell-substance nearly homogeneous. In Eozoon those
tubuli have been filled up by the infiltration of a mineral different
from that of which the shell is composed, and therefore not coalesc-
ing with it ; and the tubular structure is consequently much more
satisfactorily distinguishable In decalcified specimens,the free mar-
gins of the casts of the chambers are often seen to be bordered with
a delicate white glistening fringe ; and when this fringe is examined
with a suflScicnt magnifying power, it is seen to be made up of a
multitude of extremely delicate acicnli, standing side by side like
the fibres of asbestos. These, it is obvious, are the internal casts
of the fine tubuli which perforated the proper wall of the cham-
bers, passing directly from its inner to its outer surface ; and their
presence in this situation affords the most satisfactory confirma-
tion of the evidence of that tubulation afforded by thin sections of
the shell- wall.

The successive layers, each having its own proper wall, are often
superposed one upon another without the intervention of any sup-
plemental or intermediate skeleton such as presents itself in all the
more massive forms of the Nummuline series ; but a deposit of this
form of shell-substance, readily distinguishable by its homogeneous-
ness from the finely tubular shell immediately investing the seg-
ments of the sarcode-body, is the source of the great thickening
which the calcareous zones often present in vertical sections of
Eozoon. The presence oi this intermediate skeleton has been
correctly indicated by Dr. Dawson ; but he does not seem to have
clearly differentiated it from the proper wall of the chambers. All
the tubuli which he has described belong to that canal-system
which, as I have shown,* is limited in its distribution to the in-
termediate skeleton, and is expressly destined to i-upply a channel
for its nutrition and augmentation. Of this canal-system, which
presents most remarkable varieties in dimensions and distribution,
we learn more from the casts presented by decalcified specimens,
than from sections, which only exhibit such parts of it as their plane
may happen to traverse. Illustrations from both sources, giving
a more complete representation of it than Dr. Dawson's figures
afford, have been prepared from the additional specimens placed in
my hands (plate, figure 7).

Op. r.it., pp. 50, 51.

28

il t

1.

It does not appear to Qie that the canal-system takes it?
origin directly from the cavity of the chambers. On the contrary^
I believe that, as in Calcarina (which Dr. Dawson has correctly
referred to as presenting the nearest parallel to it among recent
Foramini/era), they originate in lacunar spaces on the outside of
the proper walls of the chamburs, into which the tubuli of those
walls open externally ; and that the extensions of the sarcode-body
which occupied them were formed by the coalescence of the pseu-
dopodia issuing from those tubuli.^

It seems to me worthy of spciial notice, that the canal-system »
wherever displayed in transparent sections, is distinguished by a
yellowish-brown coloration, so exactly resembling that which I have
observed in the canal-system of recent Foruminlfcra (as Poli/stom-
ella and Cakurimt) in which there were remains of the sarcode-
body, that I cannot but believe the infiltrating mineral to liave been
dyed by the remains of sarcode still existing in tlie canals of Eozoun
at the time of its consolidation. If this be the case, the preserva-
tion of this color seems to indicate that no considerable metamor-
phic action has been exerted upon the rock in which this fossil
occurs. And I should draw the same inference from the fact that
the organic structure of the shell is in many instances even more
completely preserved than it usually is in the Nummulites and
other Foramini/cm of the xVummulitic limestone of the early
Tertiaries.

To sum up, — That the Eozoon finds its proper place in the For-
aminiferal series, I conceive to be conclusively proved by its accor-
dance with the great types of that series, in all the essential charac-
ters of organization ; — namely, the structure of the shell forming
the proper wall of the chambers, in which it agrees precisely with
Kummullna and its allies; tlie presence of an intermediate skele-
ton and an elaborate canal-system, the disposition of which
reminds us most of Calcarina ; a mode of communication of the
chambers when they are mo^t completely separated, which has its
exact parallel in Cychdi/peus ; and an ordinary want of complete-
ness of separation between the chambers, corresponding with that
which is characteristic of Curpenterld.

There is no other group of the Animal Kingdom to which Eozoon
presents the slightest structural resemblance ; and to the sugges-
tion that it may have been of kin to Nullipore, I can oifcr the most
distinct negative reply, having many years ago carefully studied

'^*^

* Op.cit., p. 221.

29

the structure of that stony Alga, with which that of Kozo'dn has
nothing whatever in coninion.

The objections which not unnaturally occur to those familiar
with only the ordinary forms of Foramini/crn, as to the admission
of Eozooii into the series, do not appear to me of any force. These
have reference in the first place to the great alze of the organism :
and in the second, to its exceptional mode of growth.

1. It must be borne in mind that all the Foramlnl/vra normally
increase by the continuous gcunnution of new segments from those
previously formed ; and that we have, in the existing types, the
greatest diversities in the extent to which tliis gemmation may
proceed. Thus in the Ghihigvr'ma', whose shells cover to an un-
known thickness the sea-bottom of all that portion of the Atlantic
Ocean which is traversed by the Gulf-stream, only eight or ten seg-
ments arc ordinarily produced by continuous gemmation ; and if
new segments are developed from the last of these, they detach them-
selves so as to lay the foundation of independent Globigerincc. On
the other hand in Cycloclt/jievs, which is a discoidal structure attain-
ing two and a quarter inches in diameter, the number of segments
formed by continuous gemmation must be many thousand. Again,
the ReceptncnUtcs of the Canadian Silurian rocks, shown by Mr.
Salter's drawings* to be a gigantic Orbitolite, attains a diameter of
twelve inches ; and if this were to increase by vertical as well as by
horizontal gemmation (after the manner of Tlnopnrus or Orhitoi-
dcs) so that one discoidal layer would be piled on another, it would
form a mass equalling Eozoon in its ordinary dimensions. To say,
therefore, that Eozoon cannot belong to the Foramint/cra on ac-
count of its gigantic size, is much as if a botanist who had only
studied plants and shrubs were to refuse to admit a tree Into the
same category. The very same continuous gemmation which has
produced an Eozoon would produce an equal mass of independent
Glohlgerinrr, if after eight or ten repetitions of the process, the
new segments were to detach themselves.

It is to be remembered, moreover, that the largest masses of
sponges are formed by continuous gemmation from an original
Rhizopod segment ; and that there is no i\ priori reason why a
Foruminiferal organism should not attain the same dimensions as
a Poriferal one, — the intimate relationship of the two groups, not-
withstanding the difference between their skeletons, being unques-
tionable.

First Decade of Canadian Fossils, pi. x.

30

2. The diflSculty arising from the zoophytic plan of growth of
Eozoon is at once disposed of by the fact that we have in the
recent Poli/trema (as I have shown, op. cit. p. 235) an organism
nearly allied in all essential points of structure to Rotalia, yet no
less aberrant in its plan of growth, having been ranked by Lamarck
among the Millcpores. And it appears to me that Eozoon takes its
place quite as naturally in the Nummuline series as Pohjtrema in
the Rotaline. As we arc led from the typical Rotalia, through
the less regular Planorbtdina, to Tinoporus, in which the cham-
bers are piled up vertically, as well as multiplied horizontally, and
thence pass by an easy gradation to Poli/trema, in which all regu-
larity of external form is lost; so may wo pass from the typical
OpercuUna or NummuUna, through Jleterostegina and Cyclody-
peiis to Orbitoides, in which, as in Tinoporus, the chambers
multiply both by horizontal and by vertical gemmation ; and from
Orbitoides-to Eozoon the transition is scarcely more abrupt than
from Tinoporus to Poli/trema.

The general acceptance, by the most competent judges, of my
views respecting the primary value of the characters furnished by
the intimate structure of the shell, and the very subordinate value
of plan of growth, in the determination of the affinities of Fora-
minifera, renders it unnecessary that I should dwell further on my
reasons for unhesitatingly affirming the Nummuline affinities of
Eozoon from the microscopic appearances presented by the proper
wall of its chambers, notwithstanding its very aberrant peculi-
arities ; and I cannot but feel it to be a feature of peculiar interest
in geologica' inquiry, that the true relations of by far the earliest
fossil yet known should be determinable by the comparison of a
portion which the smallest pin's head would cover, with organisms
at present existing.

I nead not assure you of the pleasure which it has afforded me
to be able to co-operate with Dr. Dawson and yourself in this
development of my previous researches ; but I may venture to add
the anticipation that the discovery of Eozoon is the first of many
discoveries in the Laurentian series, which will vastly odd to our
knowledge of the primaeval life of our globe. And I am strongly
inclined also to concur in the belief expressed by T- w Dawson in a
private letter to myself, that a more thorough ext;uiination of some
of the Silurian fossils (such as Stromatopora) hitherto ranked
among corals and sponges, will prove that they are really, like
Eozoon and Receptaculites, gigantic Foramini/era.

hiiii

1

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(',iii,i(li;iii .\'.iliir;i!isl Api'il , ImIi.) .

P.i-y LH),

■■■\ ■:^;'^.^^'-;^-'-

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g«i^|&--

4. ,1 :.Si

EOZOON CANA^!'^:NSE riAWSON

'().

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81

EXPLANATION OF THE PLATE,
Illustratino thb Struoturb and Affinities of Eozoon Canadbnbb.

Of the figures here given, 1, 3, 6 a, Gh, and 7, are selected from
two plates given by Dr. Carpenter to illustrate his paper ; while 2, 4,
and 5, arc from the plates accompaning Dr. Dawson's description, and
are from drawings by Mr. Horace II. Smith, the artist of the Survey.

The figures, with the exception of 7, are from transparent sections of
specimens in which the original shell was well preserved, and its
minntest cavities infiltrated with serpentine. Figure 7 is from a speci-
men from which the calcareous skeleton was removed by an acid, and
represents the internal casts of the tubes, as seen by reflected light.

Fig. I. Vertical section of regularly stratified portion of Eozodn
showing the ordinarily continuous connection of the cham-
bers of each stratum ; magnified 10 diameters.

2. Horizontal section of Eozodn from Grenville, magnified 25

diameters ; «, systems of tubuli ; b, secondary chamber.

3. Portions of two chambers of different layers, showing at a, o,

the proper walls of their chambers ; at 6, 6, the intermediate
skeleton ; and at c, c, a stoloniferous passage : mag;iified 25
diameters.

4. One of the systems of tubuli cut transversely; magnified 100

diameters.

5. Part of a system of tubuli cut transversely ; magnified 200 dia-

meters.

6. Portions of the proper wall of the chambers, showing its Num-

muline tubulation, as seen at a in longitudinal, and at b in
transverse section; magnified 100 diameters.

7. Cast of the interior of canal-system ; an entire group magni-

fied 10 diameters.

On the Mineralogy of Eozodn Canadense,'^
By T. Sterry Hunt, M.A., F.R.S.

The remains of Eozodn Canadense, a Forarainiferal organism
recently discovered in the Laurentian limestones of Canada, pre-
sent an interesting subject of study, both to the luineralogist and
geologist. For a zoological description of this organic form the
reader is referred to the preceding descriptions by Dr. Dawsou and
Dr. Carpenter.

The details of structure have been preserved by the introduction
of certain mineral silicates, which have not only filled up the

[* See preliminary notice, Silliman's Journal [2] xxzvii, 431.]

82

I

-i,

clmnibcrs, colls, and canals left vacant by tlio disappearance of
tlio animal matter, but have in very many cases been injected
into the tubuli, filling even their smallest ramifications. These
silicates have thus taken the place of the original sarcodc, while
the calcareous septa remain. It will then be understood that
when the replacement of the Eozoon by silicates is spoken of, this
is to be understood of the soft parts only ; since the calcareous
skeleton is preserved, in most cases, without any alteration. The
vacant spaces left by the decay of the sarcode may bo supposed to
have been filled by a process of infiltration, in which the silicates
were deposited from solution in water, like the silica whicli
fills up the pores of wood in the process of silleification. The
replacing silicates, so far as yet observed, are a white pyroxene, a
pale-green serpentine, and a dark green alumino-magnesian mineral,
which is allied in composition to chlorite and to pyrosclcrit^ , and
which I have referred to loganitc. The calcareous septa in the
last case are found to be dolomitic, but in the other instfmces arc
nearly pure carbonate of lime. The nlations of the carbonate
.ind the silicates are well seen in thiu sections under the micro-
scope, especially by polarized light. The calcite, dolomite, and
pyroxene exhibit their crystalline structure to the unaided eye ;
and the serpentine and loganitc are also seen to be crystalline
when examined with the microscope. "Whea portions of the fossil
are submitted to the action of an acid, the carbonate of lime is
dissolved, and a coherent mass of serpentine is obtained, T.''ich is
a perfect cast of the soft parts of the Eozoon. The form of the
sarcode which filled the chambers and cells is beautifully shown,
as well as the connecting canals and the groups of tubuli ; these
latter are seen in great perfection upon surfaces from which the
carbonate of lime has-been partially dissolved. Their preservation
is generally most complete when the replacing mineral is serpen-
tine, although very [perfect specimens are sometimes found in
pyroxene. The crystallization of the latter mineral appears, how-
ever, in most cases to have disturbed the calcareous septa.

Serpentine and pyroxene arc generally associated in these
specimens, as if their disposition had marked different stages of a
continuous process. At the Calumet, one specimen of the fossil
exhibits the whole of the sarcode replaced by serpentine ; while,
in another one from the same locality, a layer of pale green translu-
cent serpentine occurs in immediate contact with- the white pyrox-
ene. The calcareous septa in this specimen arc very thin, and arc

my

33

trunsvorso to the plane of contact of tli«! two minerals; yet they
are seen to traverse both the pyroxene and the serpentine with-
out any interruption or change. Sonic sections exhibit these two
minerals filling adjacent cells, or even portions of the same cell, a
clear lino of division being visible between them. In the specimens
from Grenville, on the other hand, it would neem as if the develop-
ment of the EorMoii (considerable masses of which were replaced
by pyroxene) had been interrupted, and that a second growth of
the animal, which was replaced by serpentine, had taken place
upon the older masses, filling up their interstices.

The results of the chemical examination of these fossils from
ditlcrent localities may now be given : —

I. A specimen of Eozodn from the Calumet, remarkable for the
regularity of its laminated arrangement, gave to warm acetic acid
27'0 per cent of soluble matter, consisting of carbonate of lime
971, carbonate of magnesia 2-9 ; = 100.

II. Another specimen of the fossil, from Grenville, replaced
by pyroxene, yielded in the same way 12-0 per cent of soluble
matter, which was composed of carbonate of lime 98-7, carbonate
of magnesia 1'3 ; = 100.

III. In this specimen of the fossil, which adjoined the last,
sorpentine was the replacing mineral. The soluble portion from
this equalled 47*0 per cent, and consisted of carbonate of lime
9G0, carbonatcW magnesia 40 ; = 100. It thus appears that tho
septa in these specimens of Eowon are nearly pure carbonate of
lime. The somewhat larger proportion of magnesia from the last
is due to the use, as a solvent, of dilute nitric acid, which slightly
attacked the serpentine.

The pyroxene of the above specimens is a very pure silicate of
lime and magnesia ; that from I gave, by analysis, silica 54-90,
lime 27-07, magnesia 1G7G, volatile matter 0-80 ; = 100-13. A
partial analysis of tho pyroxene from II yielded lime 28-3, magnesia
13-8. This specimen was interpenetrated with serpentine, amount-
ing to about 10-0 per cent, which was first removed by the suc-
cessive action of heated sulphuric acid and dilute soda-ley. The
serpentine from III yielded silica 42-85, magnesia 41-68, protoxide
of iron 0.G7, water 13-89; = 99-09. As already mentioned, this
serpentine had lost a little magnesia from the action of nitric acid.
A similar serpentine from the Calumet, associated with the Eozoon,
gave silica 41-20, magnesia 43-52, protoxide of iron 0.80, water

C

!'

If.

84

15*40; = 100'92. Those sorpontlnos from tho Laurcntian liinc-
Btoncs arc remarkable for thoir freedom from iron-oxide, for their
their largo amount of water, and their low spccifio gravity.*

Specimens of Eozobn from Burgess differ from tho foregoing in
tho oompoHition both of tho replacing material and ecpta. Tho
latter conHist of a somewhat ferriferous dolomite, tho analysis of
which was made upon portions mechanically separat'jd from tho
enclosed silicate : it yielded carbonate of magnesia 40-7, carbonate
of lime,with a little peroxide of iron, 59-0 ; = 99*7. The septa of tho
specimen from this locality arc in somo parts more than 30 milli-
metres in thickness, and exhibit the chambers, cells, and septal
orifices ; but no tubuli are seen. The replacing material has tho
hardness of serpentine, for which it was at first mistaken. Its
color is blaokish-grecn ; but olive-green in thin sections, when it
is seen by transmitted light to be crystalline in texture. Its frac-
turo is granular, and its lustro feebly shining. It is decomposed
by heated sulphuric acid, and was thus analyzed, yielding tho re-
sult I. The centesimal composition of the soluble portion is given
under XI.

I. II. III.

fcJilictt 33-75 35-U 3G-50

Alumina 9-75 1015 1080

Magnesia 30-24 31-47 28-20

Protoxide of iron 8-19 8-60 0-54

Water 14-08 14-64 14-62

Insoluble sand 2-50

98-51

100-00

99-66

i

The silicate which hero takes the place of tho pyroxene and ser.
pentine observed in tho other specimens of Eozom is one of frc^
quent occurrence in tho Laurcntian limestones, and appears to con-
stitute a distinct species, which I long since described under tho
name of loganite, and which occurs at the Calumet in dark brown
prismatic crystals.f I have since observed a similar mineral in
two other localities besides the one here noticed. The result III,
which is placed by the side of the analysis of the Burgess fossil,
was obtained with a greenish-grey sparry prismatic variety from
North Elmsley, having a hardness of 3-0, and a specific gravity of

♦ See my descriptions, Silliman'a Journal [2J xxvi, 236,
t Phil. Mag., 4th ser., vol. ii, p. 65.

j'i

35

2' 539. These hydroun aluiiiino-n)n<j;noHinn nilicatcs, vhich I have
included under the name of lo;j;anitc/'- nre related to chlorite
and to pyrosclcrito in composition ; but these liiHt nre diHtinguishcd
from it by their eminently foliated micuctious structure.

When examined under the microscope, thr ' .ganite which re-
places the Koznihi of Burgess, shows traces of cleavagc-linca, which
indicate a crystalline structure. The grains of insoluble matter
found in the analysis, chiefly of quartz-sand, are distinctly seen as
foreign bodies imbedded in the mass, which is moreover marked by
lines apparently due to cracks formed by a shrinking of the silicate,
and subsequently filled by a further infiltration of the same ma-
terial. This arrangement resembles on a minute scale that of sep-
taria. Similar appearances are also observed in i lie serpentine whjch
replaces the Kozoiin of Orenville, and also in a massive serpentine
from Burgess, resembling this, and cr.olosing fragments of the fos-
sil. In both of these specimens also grains of mechanical impuri-
ties are detected by the microscope ; they are however rarer than
in the loganite of Burgess.

From the above facts it may be concluded that the various sili-
cates which now constitute pyroxene, serpentine, and loganite were
directly deposited in waters in the midst of which the Eozo'un was
still growing, or had only recently perished ; and that these silicates
penetrated, enclosed, and preserved the calcareous structure pre-
cisely as carbonate of lime might have done. The association of
the silicates with the Eozoon is only accidental ; and large quantities
of them, deposited at the same time, include no organic remains.
Thus, for example, there are found associated with the Eozotin-
limestones of Greuville, massive layers and concretions of pure ser-
pentine ; and a serpentine from Burgess has already been men-
tioned as containing only small broken fragments of the fossil. In
like manner large masses of white pyroxene, often surrounded by
serpentine, both of which are destitute of traces of organic struc-
ture, are found in the limestone at the Calumet. In some cases,
however, the crystallization of the pyroxene has given rise to con-
siderable cleavage-planes, and has thus obliterated the organic struc-
tures from masses which, judging from portions visible here and
there, appear to have been at one time penetrated by the calcareous
plates of Eozoon, Small irregular veins of crystalline calcite, and

* For a description of this and similar silicates, see Geology of C
ada, p. 491.

'an-

36

of serpentine, arc found to traverse-'- such pyroxene-masses in the
Eozoon-limestonc of Grenvillc.

As already mentioned in Sir W. E. Logan's description, it ap-
pears that great beds of the Laurentian limestones are composed
of the ruins of the Eozovn. These rocks, which arc white, crys-
talline, and mingled with pale-green serpentine, are similar in as-
pect to many of the so-called primary limestones of other regions
In most cases the limestones are non-magncsian, but one of them
from Grenville was found to be dolomitic. The accompanying strata
often present finely crystallized pyroxene, hornblende, phlogopite,
apatite, and other minerals. These observations bring the forma-
tion of siliceous minerals face to face with life, .'id show that their
generation was not incompatible with the contemporaneous exist-
ence and the preservation of organic forms. They confirm, more-
over, the view which I some years since put forward, tliat these
silicated minerals have been formed, not by sub&;e(|uent metamor-
phism in deeply buried sediments, but by reactions going on at the
earth's surface. f In support of this view, I have elsewhere re-
ferred to the deposition of silicates of lime, magnesia, and iron from
natural waters, to the great beds of sepiolite in the unaltered Ter-
tiary strata of Europe; to the contemporaneous formation of neolite
(an alumino-magnesian silicate related to loganite and chlorite in
composition) ; and to glauconite, which occurs not only in Second-
ary, Tertiary, and Recent deposits, but also, as I have shown, in
Lower Silurian strata.^ This hydrous silicate of protoxide of iron
and potash, which sometimes includes a considerable proportion of
alumina in its composition, has been observed by Ehrenberg, Man-
tell, and Bailey associated with organic forms in a manner which
seems identical with that in which pyroxene, serpentine, and lo-
ganite occur with the Eozooti in the Laurentian limestones. Ac-
cording to the first of these observers, the grains of green-sand, or
glauconite, from the Tertiary limestone of Alabama are casts of

* Recent examinations have sliown that some of these masses encrusted
with Eozoon replaced by serpentine, consist of crystalline pyrallolite
(rensselaerite), which seems, like the other silicates, to have replaced
the organic matter of the Rhizopod. Further examinations aided by the
microscope, are however needed to determine with certainty the relations
of the Eozodn to these masses of pyrallolite.]

t Silliman's Journal [2] xxix, 284 ; xxxii, 28G. Geology of Canada
p. 577.

t Silliman's Journal f2] xxxiii, 277. Gcolo^'y of Canada, p. 487.

crys-

37

the interior of Polythalamia, the glauconite having filled them by
" a species of natural injection, which is often so perfect that not
only the large and coarse oells, but also the very finest canals of
the cell-walls and all their connecting tubes, arc thus petrified and
separately exhibited." Bailey confirmed these observations, and ex-
tended them. He found in various Cretaceous and Tertiary lime-
stones of the United States, casts in glauconite, not only of Foram-
ini/era, but of spines of Echinus, and of the cavities of corals.
Besides, there were numerous red, green, and white casts of minute
anastomosing tubuli, which, according to Bailey, resemble the casts
of the holes made by burrowing sponges (CUona) and worms.
These forms are seen after the dissolving of the carbonate of lime by
a dilute acid. He found, moreover, similar casts of Foramini/era,
of minute mollusks, and of branching tubuli, in mud obtained from
soundings in the Gulf-stream, and concluded that the deposition of
glauconite is still going on in the depths of the sea.* Pourtales
has followed up these investigations on the recent formation of glau-
conite in the Gulf-stream waters. He has observed its deposition
also in the cavities of Mlllepores, and in the canab in the shells of
Bulanus. According to him, tLo glauconite grains formed in For-
amini/era lose after a time their calcareous envelopes, and finally
become "conglomerated into small black pebbles," sections of which
still show under a microscope the characteristic spiral arrangement
of the cells, f

It appears probable from these observations that glauconite is
formed by chemical reactions in the ooze at the bottom of the sea,
where dissolved silica comes in contact with iron-oxide rendered
soluble by organic matter ; the resulting silicate deposits itself in
the cavities of shells and other vacant spaces. A process analogous
to this in its results, has filled the chambers and canals of the
Laurentian Foraminl/era with other silicates; from the compara-
tive rarity of mechanical impurities in these silicates, however, it
would appear that they were deposited in clear water. Alumina
and oxide of iron enter into the composition of loganite as well as
of glauconite; but in the other replacing minerals, pyroxene and
serpentine, we have only silicates of lime and magnesia, which were
probably formed by the direct action of alkaline silicates, either

• Sllliman's Journal [2] xxii, 280.
t Report of United States Coast-Survey, 1858, p. 248.

38

ii

■i

■ '"HJ

dissolved in surface-waters, or in those of submarine springs, upon
the calcareous and magnesian salts of the sea-water. Experi-
ments undertaken with the view of determining the precise con-
ditions under which these and similar silicates may thus be formed,
are now in progress.

Appendix to Dr. Dawson's Paper (pages 10 — 22).

Since the above papers were published, I have had opportunities
of examining slices and decalcified specimens of Eozo'on from Petite
Nation, the locality which afibrded the specimens referred to by Dr*
Carpenter (pages 23, 26), and I have much pleasure in adding
my testimony to his observation of the distinctness of the proper wall
of the chambers from the supplemental or intermediate skeleton,
as exhibited in these specimens. In the specimens previously
examined I could not distinctly ascertain that the structure of the
proper wall had been preserved, except in a small fragment from
Burgess, not certainly known to be of the same species with the
specimens from Grenville. Although I believed that such a
distinction must have existed, I could not affirm that it had been
preserved. I therefore regard these additional structures, ascer-
tained by Dr. Carpenter, as affi)rding strong confirmation of the
foraminiferal nature of Eozoon, and as indicating its high rank in
the order of Foraminifera ; while at the same time no more satisfac-
tory guarantee for the correctness of the observations made here
could be given, than the concurrence of one whose authority in
such subjects is deservedly so high.

It is also gratifying to find in recent British publications,* notices
to the efiect that Mr. Sanford hris found the structure of Eozoon
in the Laurentian limestone of Ireland), the Connemara marble of
the Binabola Mountains) already referred to on page 22. Mr.
Sanford's specimens have been further examined by Prof. Rupert
Jones, who says : " except that the serpentine replacing the sarcode
is lighter than in specimens furnished by Sir William Logan, there
is no real difference between the two." Eozoon Canadense will thus,
in all probability, be found to be characteristic of the Laurentian,
and possibly of a particular portion of that series on both sides of
the Atlantic, and will become important to palaeontologists as a
means of recognizing rocks of this early life-zone. It would appear
olso that in Ireland as in Canada the remains of the creature have

• Geol. Mag., Nov. 1864 ; Reader, Feb. 25, 1805.

upon

39

contributed largely to the formation of limestone, since Prof. Jones
remarks that he has detected its structure abundantly in chips of
' Irish-green ' marble from marble-works in London ; and Mr.
Sanford represents a somewhat extensive bed of limestone in the
Binabola Mountains, as abounding in it throughout, though not
always in a good state of preservation. j. \\. d.

JOHN liOTELIi, PBINTIR.