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32X

McGILL UNIVERSITY, MONTREAL
NOTES ON SPECIMENS— NO^^EMBER, 1894

^. -^

EEYISION OF THE

BIVALVE MOLLUSKs'^^v^'^

OF THK

'ji

Coal-Formation

NOVA SCOTIA.

SIR J. WILLIAM DAWSON, LL.D., F.R.S.
F.G.S., &c.

Peter JRedpath Museum.
1894

!l ■■

■

BIVALVE MOLLUSKS

OF THE

COAL FORMATION OF NOVA SCOTIA.

By Sir Wiiliam Dawson, LL.D., F.K.S.

(Ri'priiitdl from flu- CnnaiUdu Hrronl of S<iniri\ Octolnr. ISilJ.)

The abundant occurrence of shells of bivalve mollunks in
the beds .-tssociated with coal has long attracted the atten-
tion of collectors on both sides of the Atlantic, and various
opinions have been entertained as to the affinities of these
animals, the nature of their habitat, whether freshwater or
marine, and the manner in wiiich they became associated
with the coal and its accompanying beds. They occur in
extreme abundance in some of the beds of bituminous and
carbonaceous shale and in bituminous limestones, and more
sparingly in argillaceous and arenaceous shales, throughout
the coal-fields of Nova Scotia and Cape Breton, and natur-
ally excited the interest of the writer in his earliest explor-
ations of these beds. It is to be observed also that they
not 'nfrequently occur plentifully in the roof-shales of
beds of coal.

They were noticed in one of my earliest papers on tbo
coal formation of Nova Scotia in the .Journal of the Geo-

1: Notes on Specimens.

loji^ical Society of Tjotidon in 185;i' In thin lU'tu'.le T
fij(m-C(i four species of bivalviffs from the coiil-foimation of
the South Jogjjjins, but without doHcriptionH. Two of thorn,
one the common I^aiadltes and unothera narvow Antliracomi/a,
wore referred to Modiola. 1'wo others woi-e refei-red to
('nio. One of these is an vln^/tra(?o?H//rt of lJnio-lil<e form.
The otlier appears, to bo a Carljonicola. perhaps O.
cmijulafa. 1 romarUod at the time on the vast alumiance
of these Shells and their apparently freshwater habitat.
This was the first publication so far as I know of these
fossils from the Nova Scotia coal region.

These shells wei-e further referred to in th) first edition
of " Acadian (roology" in 1855; and in the su])plement to
that woi'U issued in 1860, T proposed for them a newj^enoric
r\fiXi\Q,Naiadites. and described them in the following terms,
which I quote here, as indicating conclusions which have
to a lai'ge extent been verified by subsequent discoveries.

" The so-called >r()diolio of the coal-measures are still un-
certain as to their affinities. Thoy do noi come within the
characters of the genera Cai'diiiia, Anthracosia, itc, to
which fossils occurring in similar situations in the Hritish
coal-fields have boon referred. They aro all thin shells,
marked with growth lines, but destitute of other ornamenta-
tion, and, so far as can bo observed, without tooth. In so
far as external foi'm is concerned they may all bo referred
to the genei'a Modiolu and Anodon. J?ut mere form may-
bo a very fallacious guide, and 1 shall notice what seem to
me to be the distinct specific foi'ms under the jirovisional
name Naiadites, intending thereby to expicss my belief that
tboy aro probably allied to the Unionida\ They aro cer-
tainly distinct from any of the shells nf the marine carboni-
fermu limestones, and ai-o never associated with marino
fossils. It is possible that their neai'ost living analogue is
the Bi/s'iO-anodonfa of D'Orbigny, from the River Parana."

At the same time five species wore described, and indica-
tions were given as to their local and stratigraphical
distribution. A sixth species was subsequently discovered,

Vol, X, p. 39.

Bivalve SkelU of Nova Scotia.

and another roforrcd to the Hamo ,i,n'oiip has since l)Oori
found to belong' to tho <,'crius Anthraco^ia or Carhonicohi.

Ileforo the ))iil)li(ation of the second o lit ion of " Acuilian
Geoloijiy" in IHIJS, I iuid sent spociinons to my friend, the
late Mv. Salter, of lae (ieologicul Survey of (Ireat Britain,
who was at the time studyint^ the Hritisji species, and he
described tliena with some other fossils from Xova Scotia
which I had placed in his hands, in a paper in the Journal
of the Geological Society' with figures of three of the species,
which he referred to his two new genera Anthracoptera
and Anthracomya, then recently established for the British
species. Ho thu- diopped my genus '• Xaiadites " aiul
substituted two other names of later date. I might have
objecied to this, but I have made it a rule never to raise
(lucstioiis of priority or of mere nomenclature, and I I'elt
quite sure that Sailer was not a man to do any injustice,
while I fully recogni/od his superiority as an authority on
fossils of this Uind. There was, however, a more important
point involved, having relation to the whole question of the
conditions of accumulation of coal. Salter held the shells
to be probably marine, and on this ground my name
Naiadites was objectionable to him, while one of his names,
Anthracomya, implied the idea of burrowing creatures allied
to the ATya or sand clai Now, throughout the whole
thiclcnes.s of the coal-formation of Nova Scotia, there is an
entire absence of the species of marine moUusks found in
the underlying marine limestones, while the bivalve shells
in question occur almost exclusively in the coal measures
and are not found in the ailmittedly marine beds. The
question was an imjjortanl one with reference to the mode
of accumulation of coal, a subject then engaging my atten-
tion ; for though the occurrence of a i'ow e.vceptional bods
holding marine shells might be explicable as the result of
occasional invasions of the sea on beds usu;illy beyond its
roach, the association of those shells with the Ijeds of coal
was so constant and intimate that if they could be proved
to be marine, a similar conclusion might naturally bo

1 Vol. XIX, p. 80, 1863.

4 Notes on Sperimenx.

roachod rcs|)ocling tho coul itself, utui even Horiu' of tho
plaiitH associiitwl willi it. 1 ihorcforo submittod to Mr.
Sailor and pulilishcd in my new edition the foilowinii; tiictH,
teiulin^f to hIiow that niy so-called Nuiuditos were froah-
water or ostuaiine shells.

1. Under the microscope the thicker shells, even those of
the Anthracoptera type which most resemble marine species,
present an internal lamellar and subnacreoiis layer and a
thin layer of vertical pi-ismutic fibres, covered with a well
developed epidei-mis in the manner of the shells of the
Unionidieor freshwater mushcls.

2. Th'j liii;ament unitint; tho valves was external, and
there seem to iiave been no hinge teeth. The shells wore
closed or very slii(htly o])en posteriorly, and in s()mes])ecies
there are indications of a byssus or '• beard " for attach-
ment. The jfenoral aspect is in some species that of
mussels, in others that of Unios or Anodons.

3. I know of no instance of the occurrence of these shells
in the marine limestones or in association with species
known to be marine.

4. The mode of their oe-cui-renco precludes the idea that
they were burrowors, and favors the supposition that they
may have been attached by a byssus to floating timber and
to one another.

5. Tlie attachment of shells of spirorbis to tho outer sur-
face of many specimens seems to show that they wore free
in clear water wlicn living, wliile the dense piling together
of these f^hells in some beds almo^tt unmixed with othei-
material, and their occasional occurrence in patches asso-
sociated with fossil wood, points to the same conclusion.

(I. They are associated witli tine sediments, vegetable de-
bris, the crusts of minute crustaceans and remains of fishes
more likely to have been iidiabitants of fresh or bi'ackish
water than of the sea.

On these grounds, and being unable from the specimens in
mypossession to make out evidence of generic distinction,!
continued to use the name Naiadites; using however, Salter's
names as subgeneric, so as to keep our species in harmony
with those of England as described by the Geological

Bi'Hi/ve Shel/s of Nom Scotia. 6

Survey. The miitlor vvhk \vAl in this form in my cilitioa
of 18(;s. It Heoms, hovvevor, tlmt in Hiibstitiitin^' a ti^'uro
not poriiaps very uccuratoly druwii fi-.>m a flutloneil Hpoci-
mon, for llio fi^nire which Suitor hml ^tjivoii fi-om an ani^uiar
and com I trussed oxam|)lo, I caiHcd Homo misnndoi-standiiiLf
as to one of the specios, loadiiii,' to tlic HUpposition tiiat
one of thoHo named by SaltcM- wan dirtoront from that which
I roco^'ni/,od by the same name. Tho ditforonco was really
in state of pi-esorvation witli some inaccuraev in drawing'
in both canes, I Mhall <,mvo below copies of these imperfect
fi^'ures, which however, represent actual appearances wliich
may mislead collectors, alon« with a ti^nire carefully copied
from a youn<i: Hpecimen less distorted ihari usual.

Sul)sequently to 18fi8, the pressure of other work pra-
vented me from ^nvin^' any further attention to these shells,
except in collectinif such specimens as occurred to me in
my visits to the coal-tields of Nova Scotia, and placin,<r these
in drawers and collectinjr-boxos along with the older
material. In tho autumn of 1892, however. Dr. Wheolton
Hind, F.Cr.S,, who had undertaken a thorough revision of
the specimens of this kind in English collections, was so
kind as to invite me to place in his hands for study and
comparison specimens of tho specios 1 had described. Un-
fortunately his letter arrived at a time when I was in-
capacitated by severe illness from attending to the matter,
and was unable to avail myself of his kindness until after
the publication of his paper on the British species in 1893.
As soon as possible, hovvevor, a suite of specimens was sent
to him, along with a note on thoir mode of occurrence and
distribution, and tho result was a joint paper which appears
in th . Journal of the Geological Society for August, 1894,
on which the following statements are based.

On examination and comparison with British specimens,
some of which are much hotter preserved than ours, Hind
concludes that my seven species, excluding one which he
believes belongs to tho genus Carbonicola of McC^'oy, Aathra-
cosia of King, are referable to two genera which may be
named JWiiadites (Anthracoptera of Salter) and Anthracomya
of Salter. The first may bo regarded as a member of the

Notes on S/iecitiiens.

Ihiiiily .Myliliilii' (»!• niiissils, llii' sccor.'l as alliwl to Aitodoiis
ill I 111' I'atnily of llic' Uiiioniiia' or t'lcsliwator miissols, as
tliey uro HOinotinit's callod

Mr. VVhoultoii Hind gives llio cliaracli'rs of ilw gcnoia in
I'till, l''oi' llu'so cliai-actiMs reference may he mado to his
liapf!! ' , lull foi' till' hciKlil of colk-ctoi's, the followini^ sum-
mary ot llio more im|i()itarit oxterna! jtoints may lio iii-
sertod hero.

Genus, NAtADiTEs, Dawson.

{Anthraciij)hr(i, Sailor.)

vShoil .Modioia-lik*', somewhat triangular in form, iiroad
and rounded hehind, comewhat pointed in front. heaU at
anterior exlrensity. almost ternii'Mil, and extending ohlicjuely
hat'kward in a nutro or less pionouneed ridgo, hingo-lino
Hti'aight, Hometimes .showing delicate internal Htriio, teeth
rudimenlar}- ; e)ii<lei'mis somewhat wrinUled, surfaeo with
eoncentiic lamelhe and line-^ of giowth. A few sj)ecimen.s
showing the interior indicate that the hingo-j)lato was finely
striated, and that there was a Iritid anterior muscular sear
and a larger single jtoslerior one.

1, Naiadites carbonarhis, l>awson.
1 2

ss^^-

l''i>:ures 1 ^o'^. — N(ti<i<li(iii (•iirJinnariii.i,'M\(]t\]f\ Coal-forniation,
K ,Tni.'jiins. I and 2.— Orifiinal fi^jiires from imperfect specimens,
;i — Mon* jierfect si)ecimen, enlarged x L'.

' Joumiil of Geological Society, May, 1893.

Bii'ti/m :S/ie//s of Nova Scotia 7

Jonrnal ..f (ie<,io;.i,;al Su.ioty. V.,i. X, is:,:!; S„ppletnontto Aci.lian
<. oology, ISflo, p. i:;; Snltor. Journal cf < ieulovriciii Society
(Anthraooptora). V..I. XIX, isii,!, p. 7-.); Acuiian (iouiuKV, •.•..<!
H.litio.i, ISds, p. I'lU; Wl.oe.ton Hind, Joun.ul of (}eoloL'ical
Hooiety, \'ol. L, ih'm.

Thirt i.s tho moHt common spocios of t|,o ^r,.nus, and in vory
Jibnnduiit in somo .shulcs and bitiunimnis lii..e.stonos of tho
c-oul-fornuition. 80 ,„u,.l. is this tho caso, (hat some thin
buLs may bo Huid to bo made up of those sholls, vvhi.h
thoui^'h somewhat Htiong, ai-o oftcM. much compressod and
distortfd, so that it is .,fton ve,y ditticnit to obtain iiorfuct
oxampies. In beds whore they are loss pletitilu! they are
usually much Hatt(M.od, by which tho -eneru! uullin^ ..f the
shell is greatly moditiod. Owing to those circumstancoH
and also to the fact that tho shell is rounder when young
and becomes more angular and elongated with ago, it is
difficult to select typical specimens— hom-e tho ])ublishod
tiguroH are dissimilar. When perfect it may bo described
as somewhat (|uadrate, beak anterior, obtusely pointed,
hinge line straight, two-thirds the length of ^hell, ventral
margin with slight sinus, posterior margin broadly
rounded, urabonul ridgo prominent.

my papjr of 1853 in "Acadian Geology" second edition, in
Salter's paper of 18()3, and in Wheelton Hind's j.aper of
1894, or Hguros 1, 2 and 8 of this paper).

This shell is very near in form to Naiadites modiolaris
(Avicuta modiolaris of Sowerby), and also to some forms of
N. tumida Btheridge, resembling them in somo i-espccts so
closely that it is difficult to distinguish some of the Xova
Scotian .specimens from those Hnglish form.s. It is also
near to N. (Modiola) Wijomirvjmsis Loa, of the Pennsylvania
coal measures. These forms may certainly bo regarded as
representative species.

It is not improbable that somo of the shells from tho
Carboniferous of Illinois and Ohio, which have been referred
to the genus Mijalina, belong to this genus, as suggested by
Dr. Hind, Meek and Worthen have also referred a species
from the Keokuk group (Lower Carboniferous) to the genus
Anthracoptera (Naiadites)— .4. fnitjiMs M. and W.' White
has described N. Polita {Anthracoptera polita) from the
coal measures of the West,-

' Chicago Academy, 1880.

- U. S. Geological Survey, XII, 1880, j.. 160.

Notes on Specimens.

Thero can be little doubt, from internal niiirkin^rs and
cxtci-iial form as well as from mode of occurrence, that
these shells were anchored hy a byssus to floatiiiir timber
and to one another, often in ^--reat masses, Just as the com-
mon mussel is found attached to floating logs in the
estuaries of modern Canadian rivers. Mr. Ktheridgo has
noticed a giou)) from the coal-formation of Scotland, appar-
ently attached to a stem of a calamite, and Dr. Jlind has
n(.ticed the same fiict. The specimen is in the collection of
the English Geological Sm-vey.

The specimens in my collections in the Peter Kedpath
Musciim, are principally from the South Joggius, where
myria<ls of those Hhells occur in scmie of the shales as thickly
packed together as j)0ssil)le. Other specimens are from
Picloij and from Mahou in Cape Jii'eton. They are con-
fined for the most part to the middle portion of the coal-
formath.n of which they are very characteristic, whereas
the shells of the next genus i^ange in great abundance from
the millstone grit to the newer coal-formation inclusive.

2. Kaiadites lonyus. s. n. -

Fi^r. A.-XamdHe^ lou./w, s. n. INIiddle Coal-formation, S
•logu'ins, enlarged, x l'. cvhuh,

Wheelton Hind, ckmjr variety of A', nirhowinus), .Journal r,f Geolo-
gical Society, Vol 1,, ]si)4, p. 44(i, PI. XX, Fig. I.

This (,hell. whi(d^ occurs rarely i,i beds associates' with
those holding the typical N. mrbonarins, is regarded by Di-
Wheellon Hind as a variety of iho i)!-eceding. It differs
however, very much in form, and there do not appear to he
intermediate specimens, while it is rare and solitary, and

Biva/ve Shells of Nova Scotia. 9

w(,ul<l cither Beem to have been lesHgresariouH in its habitH
or to be represented by mere stragglers from its proper
locality. It may therefore, be not unreasonably regarded
Hs a distinct species. Most of the specimens in our collec-
tions are from the South Joggins, but there are some from
tape J}rotoii. Oom])aro IV. triangularis, Sby.

3. Naladites mytiloides, s. n.

BretS?- i^fl "'■"'''''''"• '■ "•' ^''•'""^y ^''^rner, Cape

This small and pretty species has more the aspect of
modern mytili than the others, but its internal markings
are unknown. ft is narrow in front, with the hinge-line
Hlightly curved and the shell widening to the rounded
poaterior end, where it is regularly curved. The ventral
margin is slightly incurved and flattened in the best pre-
served specimens ; but most of the specimens are more or
less crushed. The epidermis is not preserved, and the sur-
face shows only a few concentric growth-linos.

These shells occur abundantly, but for the most part
broken or crushed, in shale from the coal-formation of
Chimney Corner, Cape Breton, collected by a former student
of McGiU, Mr. Neighswander. They are nearly uniform in
size, about half an inch in length. This shell is from one of
the more northern ])arts of the Cape Breton coal-fields. It
may be compared with Myalina meliniforvus, M. & \\\ from
Illinois, also with N. Oarinata, Sby., England,
frenus ANTHRAcoMrA, Salter.
Shell transverse ; slightly inequivalve inequilateral, the
anterior end being small and rounded, the posterior end
rounded and wider. Umbones usually near the anterior
end. ilinge-line straight without teeth ; ligament external ;
in'lications of a byssal furrow in front in some species; sur-
face marked with concentric lamella and ridges of growth.

Notes on Specimens.

Epidermis thick and sometimes wrinkled, especially in
flattened specimens, shell substance usua'ly very thin.

Shells of this genus are more widely distributed, both
locally and in time, in the coal-formation of Nova Scotia,
than those of the pi-evious genus. Shale surfaces are some-
times crowded with them, though they do not so much
enter into the composition of beds of some thickness.
There are several species, varying a good deal in form,
some being nearly circular, while others are much elongated.
There are also two types, one more attenuated and gibbous
in front and therefore assuming a more mytiloid aspect
{e.g. A. elongata), the other more regularly oval and Unio-
like in form (e.g. A. arenacea). The first type is in some
degree a pausago, so far as form is concerned, to the genus
Naiadites. The internal surface is not known.

It is noteworthy that while several of the species range
from the Lower Carboniferous or the millstone grit to the
upper coal measures, the individuals are usually smaller
and more depauperated in the lower beds.

1, Anthracomya econgata, Dawson.

Figs. 0, 7, S— Anthracomya elongata, Middle Coal-formation

tii^^fT T^ ^i*^°^'' ^-^ ^^"'°"- *>• «-Small specimen .natural
size and enlarged. F,g. 7.-Large specimen, natur^size. Fig. 8.-

SJSSr'EnTar'ged Tlf'' ""'^^^^ ""^ anterior end sl^tly

Bivalve Shells of Nova Scotia. U

Supplement to Acadian Geology, 1800. p. 4:5 (as xVaiadites) ; Salter
Journal of Geological Society. Vd. XIX, 1868, p. 79; Acadian
Geology, second edition. I8(i8, p. 20;; Wheelton Hind, Journal
of Geological Society, Vol. J., 18<J4.

This species is characterized by an obliquely ovate n)rm
in typical specimens, the len-th being about double the
breadth. The umbones are somewhat elevated and near the
narrower anterior end. The straight hinge-line is somewhat
oblique and a little more than onethird of the length of the
shell. The front margin is slightly sinuated, the posterior
nriargin regularly rounded. The surface is smooth and
shining, with concentric lines of growth.

This is by much the most abundant species, and is very
variable in form and size. When aged, it is more elongated
than when immature, and the hinge-line is relatively
shorter and less elevated. It often has shells of spirorbis
attached, and occurs in patches in beds holding vegetable
fragments, in a manner to suggest that it may have been
attached to these.

The collection in the Peter Eedpath Museum contains
specimens from various members of the Carboniferous
system, and from the South Joggins, Pictou, Sydney, Glace
Bay, Mabou, Riversdale, Swan Creek and Parrsboro. The
shells from the three latter places are fiom beds low down
in the system, and are of small size. In general form this
shell resembles A. Williamoni,W .mnd, of the English coal
measures, but is less elongate.

2. Anthracomya laevis, Dawson.

^S^'^-

h^i^-O.-Anthracomi/a ^am^, Middle Coal-formation, S. Joggins^
patural size, and enlarged . "

Notes on Speci/nens.

Supplement to A.^a.lian Geolofry, last edition, (as Naiadites)
Salter, Journal of (JeoIoKical Sodety, last edition; Acadian
.eoiogy.second edition, p. 205; Wheelton Plind, Journal of
(jGOlogical Society, 1. c.

This JH small, broad-ovate, the HmaiJ umbo about one-third
of the distance from the anterior end of the .sti-aight hinge-
line To the naked eye the younger shells seem almost
circular. The shell is very thin and the epidermis smooth
and shining, and much wrinkled in flattened specimens
This litlle shell has been found in only one bed, a black
shale ,n the lower purt of the .loggins coal-measures near
the upper ,,art of the millstonegrit. It resembles A. Scotica
ot Crreat Britain.

3. Anthracomya aremcea, Dawson.
10

enlarged ^xT*'*"""'""'''"^" '"''''"'''''> ^pper Coal-formation, Pictou.

Supplement to Acadian Geology, last edition; Salter, Journal of
G.olog.ca Society, second edition, p. 205; Wheelton Hind
Journal of Geological Society, 1. c. '

Shell elliptical, smooth or with very fine concentric lines.
I'.pidermis tliin, in many specimens absent. More than
twice as long as wide. Anterior margin narrowed in front
of beak. Beaks about one-sixth of the length from the an-
terior end. Posterior end somewhat narrowed at extremity

This species is usually found in gray arenaceous beds of
the upper coal-formation and the millstone grit. It is com-
paratively rare in the middle coal-formation.

All our museum specimens are from Pictou and Sydney.
The species may be compared with A. lanceolata of Great
Britain.

Bivalve Shells of Nova Scotia.

4. Anthracomya nvnlis, Daw

son.

BnlaSd^T'^""'""""''" "'""■'' ^^"^^'"'" ^'arboniferous, Pamboro.
Supplement to Acadian Geology, I8.i0; Salter, Journal of Geo-

r'4r. 'wf ';,'■"; r'Tv '''''''^" ^-ology. second edition..

p. -05 , W heelton Ilnul, Journal of Geological Society, 1. c.
Ih.sspeces has the general form of the .smaller speci-
meuH ofelongafa, but i. broa.ler bohiud and more tumid in
tront, 80 as to be at once distiniruishable by the eye It
occurs .paringly in bedH from the millstone grit and lower
Carboniferous to the middle coal-formation.

Oiu- specime,:s are from the South Joggins, Riversdale
and Parrsboro. It may be compai-ed with A. dolabrata of
Jingland, but is always much smallei-.

5. Anthracomya obtenta, Dawson.
12

Cape^'lSeto/al'tumUiT ''''""' ^'''^'^^' ^^oal-fonnation, Mabou.
Acadian Geology, second edition, p. 205, (as A. ohiusa, a name

Which 1 hnd was pre-occupied for a species now included in

tins genus.) ];]

*• -^j*^- J'''""'^"/'"""^""'"'^^'''^"'"' <^'Oal-forniation Pictou restora
tionof a Hattened and imperfect specimen, enlarged x 2 '

Notes on Specimens.

(Jonoriil foiin rounded, and piobahly when not chan,'?ed by
prcHHiii'c tumid. Anterior end l)i'0{id and ubi-uptly i-ounded ;
hinge line Hti-aiijht. Hcaks raisoii and Komewhat near the
front; lower and po.sterior inari>;inH broadly i-ounded. shell
thin, wrinkled when flattened, strongly marked with
growth-lines.

This species resembles sjmewhat A. Adamsii var. erpansa,
England. It is rare. Our only specimens are from McLel-
lan's Brook, IMctou, and .Mabou, in Cape Breton, and are
mostly rtattoned, except some very young examples from
llie latter ))lace.

In addition to fragments of plants and comminuted
debris of vegetable 'natter, the beds holding Naiadite.s,
contain a number of other animal remains, constituting a
peculiar fauna altogether different from that of the lower
carl)oniferous marine limestone, and also in many re8|)ects
distinct fi'om tiiat of the sandstones of the millstone grit
and upper coal formation. This fauna, though not that
which we would expect in fresli-water lakes or streams
under ordinary conditions, seems of such a nature as to be
appro])riate to bodies of shallow, fresh or brackish water
loaded with vegetable matter, or to wide and sluggish
creeks travoi-sing the g'eat swamps of the period, and
occasioiuilly wiilening into lagoons, receiving much fresh
water from the land, and having but little communication
with the open sea. The beds supposed to be thus deposited
are carbonaceous or bituminous shales and' laminated,
impure limestones full of earthy matter, and blackened
with bituminous and carbonaceous debris, In addition to
the bivalve shells in question, they contain vast numbers
of minute bivalve crustaceans. (Bairdia and Carbonia) '
Species of Eurypterus, JJiplosti/lus and Anthropalaemon,
re])resenting crustaceans of higher types. Great numbers
of the little Spirorbis carhonarius are also attached to many
of the i)lants and other fossils. Numerous scales and teeth
of ganoid fishes of the geneia PaUvonixcus, Mhizodus, &c.,

' Rupert J Olios, London (Jeologiciil Miigaziiie, AuBusit, 18iM, p. 2t'.l), and .June,
1889, p. 356.

Bivalve Shells of Nova Srolia.

alHo oci'iir, and teotli ol .lipnoid H.slu's (' tetwdns), uIno various
HpecioH of sharks {Ctenopty chins. Psammodus, Diplodus, kv).
Soino of tlieso sharks must liavt" attained to a considerablo
wizo, and the}' no doubt found accoss to th^? inhuid waters
by the outlets comrnunicatinii,' with the sen, and wore
attracted to visit tiieso C'onij)arative!y impure higoon.s by
the ubundunco of food which tlioy atfordod. ' Very i-arely
there have been found in these beds bones of ain])hibianH
and shells of pulmonatc sun\U,{Pupa vttmia. &c.). Animals
of these kinds no doubt haunted the mai-gins of the lagoonw
or creeks; but only occasionally left their remains in
deposits accumulating in tiicse places.

We ])erhaps obtain a glimpse of purer inland waters,
similar to ihose of modern Canadian lakes, by means of u
remarkable shell, discovered by Mr. Weston, of the Geo-
logical Survey, at the .South Joggins in 1893, and which
has been described by Mr. Whiteaves, K.d.S., under the
name Asthenodonta Westoni. - It resembles in general form
the large jiearl-uiussel of our modern lakes. (Manjaritana
maryaritifera L.) and some sjiecimens are no less than nine
inches in length, and of somewhat massive thickness
anteriorly. It was found in a sandstone with drift trunks
of trees, and may have come from some distance inland.
Such a .-hell could scarcely have been a companion of our
little Naiadites or Anthrocomyiv, and points to more favoi'-
able conditions for fresh-water molluscan life in lakes or
largo streams in the interior of the continent.

Conditions tiivourable to such mollusks vvere probably, as
I have elsewhere suggested, more i)i-evalent in the later
Erian or Devonian than in the < 'arboniforous. Hence the
occurrence of such large Anodon-like shells as Amniyenia
CatUkillenm, Hall in New York, and Anndon Juke&u in the
Kiltorcan beds in Ireland. The above discovery however now
gives reason to believe in similar conditions as oxistinn' in
higher grounds contemporaneously with the great coal
swamps of tlie low plains of the carboniferous period.

' Notices of this fnuiiii will bu found in Aciidian geoloev, pp. 2(i" et sen
nndsuppleinentH. * ''

- Trans. Royal Society of Canada, Section iv, 18!^

Notex on Specimen.

Tli<! picture preHcnted by the wide swamps and dark
))()nds and slui;i;iHh stroams of tho coal-formation period,
with (ho creatures of low or^fanization by which thoy wore
inhabited, is not an attrc...Mve one ; but these conditions,
which spread so widely over our (continents in the carbon-
iferous period, were those suitable to the accumulation of
tho great deposits of coal so essential to us in the present
condition of tho world. The animals which form tho sub-
ject of the present paper, though of little value or interest
in themselves*, give much information as to tho conditions
of accumulation of coal, and it is a source of gratification to
tho writer of this |)apor to find that as interpreted by thoir
latest investigator, Dr. Wheelton Hind, tliey tend to estab-
lish more firmly the conclusions as to the manner of the
production of coal-bods for which ho has contended for so
many years, and which are so well illustrated by the
admirable sections of tho coal-bearing rocks seen in the
coast-clitl's of Nova Scotia and Capo Breton.

Throughout the thousands of feet of such rocks, con-
stituting the ])roductive coal-measures as exposed in these
sections, I have shown ' that there is an entire absence of
properly marine or oceanic remains; and the accumulations
of sediment and organic matter, and the animal and vege-
table fossils so abundantly present, all point to the existence
of wide swampy flats, traversed by ditch like crooks, and
with shallow lakes or lagoons, supporting an exuberant
plant-life, and from time to time inundated. In this
way tho beds of coal, underlaid as they are by underclays
with roots, and overlaid by clays and sands containing pros-
trate and drill j)lants, and associated with beds holding a
fauna appropriate to such conditions, were accumulated
by growth in situ in the manner of modern bogs. The
accumulation of successive beds with intervening shales am;
sandstones, is due to tho gradual or intermittent subsidence
of the areas of deposition under the weight of the sedi-
ments laid down upon them, as we see at the present day
in th-,- deltas of great rivers.

' Aciiiliiin Ki:iiI(iK,v,chu|). \I.

Biva/ve Shells of Nova Scotia.

Such were undoubtodly the conditions of coal accuniulu-
tion; but wo must l.o proparod to admit many oxceptional
casea. Vast areas of bog imply great tracts of water-
soaked and inundated ground, filling i;p with drifted vege-
table muck. They also necessitate such casualities "as
bursting of bogs and the floatage of their semi-fluid contents
over large areas, as we find now occasionally occurring in
Ireland and in Florida. To such causes we may attribute
bods of earthy bitumen and of cannel coal, and possibly the
coal containing fish scales which I have described in the
Joggins section ' or the celebrated Jarrow coal in Ireland,
recently so well described by Mr. Bolton ^ in which fossil
fishes and batrachians occur imbedded entire in the coal
itself, as if they had been overwhelmed and buried in a tor-
rent of vegetable mud. The Jarrow coal is also, over a
large part of its area, destitute of an underclay or "seating"
as it is called in Ireland, and it thins out in different direc-
tions, as if it had been formed in a limited depression of the
surface. Su'di beds constitute the exception which illus-
trates if it does not prove the rule, by showing how different
our ordinary coal beds must have been had they been
formed in such special and peculiar ways.

It is further to be observed that while in many places
the coal-formation swamps have been elevated into uplands
and mountains, in other regions thoy have been depressed
beneath the sea. The island of Cape Breton affoi-ds an
excellent example of this. It consists of two broad ridges
of old Paheozoic and Pre-Cambrian rocks with a carbon-
iferous depression in the middle, and belts and patches of
coal-formation beds around its sides, dipping towards the
sea. The soundings show that these coal-formation areas
are continuous under the sea with those of Nova Scotia
proper on the South and Newfoundland on the North, and
that they extend to great distances under the Atlantic to
the East and the Gulf of St. Lawrence to the West. Thus
we can imagine Cape Breton in the coal-forraation period

' Acadian Geology, pp. 164, 199.

' Manchester Transactions, Vol. XXri. Part 16, 1894.

Notea on Specimens.

to have consiHtcd of u,, olovutod imoIeuH of older roclcs,
pofhaps with int(M-ior lakes, while around it stretched a
great level expanse of boc^s and lagoons now in groat part
Hubmergod. There tnighl thus be a very marked distinc-
tion between the hills, thinly covered perhaps with I<'ern8
and Pines, with clear fresh-water lakes, and the vast swamps
densely clothed with Sigillaria>, Lepidodendra, Oalamitos
and Cordaitos,and with dark bodies of impure water full of
vegetable matter. The faunu' of these districts might bo
equally ditforent. We know little as yot of the upland
fauna; but may hope for more discoveries in this direction,
especially in countries like Xova Scotia and Cape Breton'
where there were elevated districts in the midst of the
ai oas of coal accumulation.

Appendix.

Note on (Janus Carhonicola, Mcf'oy. (Anthraromi, Kinj;.)
This genus, which occurs abundantly in the Coal Forma-
tion of Great J3ritain, is represented, so far as known, in
Nova Scotia by only two small species, both from the
lower ])art of the Coal Formation, <,r possibly from the
Lower Carl.oniferons. One of the.se is (\ atujidata {Naia-
(Utea anipilata, Acadian GeoloMry, p, 204, tig. 4(;.) \t jg
tVom Parrsboro, from beds holding tbssil plants and, so far
as known, no marine shells. The other, 0. liradorica
{Anihraco&ia Bradoriea, Ac. Ceol., j). 314, tig. lli'J b) is from
a shale supposed to be Lower Carboniferous, at Haddeck,
Cape r.retoii. The affinities of these shells are at present^
uncertain, but will probably be discussed by \)\: Wheelton
Hind in u ibrthcoming paper, its associations would seem
to iiKifcMc that the habitat of some of the species was simi-
lar to that of the genus Anthraromya, which at Parrsboro
are found in neighboring beds. The figure of C, Bradoriea
is i-eproduced here to show the characteristic form.

Carhonicola Bradoriea.