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Collect 1 4>«*^

IFrom the Qttarteelt Journal of the Geological Society for
August 1894, Vol. 1.]

Note on the Genus Naiadiies, as occurring in the Coal Forma-
tion of Nova Scotia. By Sir J. William Dawson, C.M.G.,
I,L.D., F.R.S., F.G.S. With an Appendix by Wheelton
Hind, M.D., B.S., F.R.C.S,, F.G.S.

[Plate XX.]

In the autumn of 1892 Dr. Wheelton Hind was so kind as to invite
me to place in his hands, for study and comparison, specimens of the
bivalve shells from the Coal Formation of Nov9 Scotia, which I had
described under the above generic name, ^ and some of which were
described by the late Mr. Salter in the Quarterly Journal of this
Society, vol. xix. (1863), under his new generic names Anthracoptera
and J.nthracomga. Owing to illness I was unable, at thb time, to
comply with Dr. Hind's request, and thur^ the Nova Scotian species
lost the benefit of a detailed comparison with the British forms in
Dr. Hind's excellent paper of May 1893.'' I have now sent a col-
lection of specimens to him, and beg to make the following remarks
thereon.

These she?'- occur plentifully in some of the argillaceous shales
of the Coal j. ormation, and occasionally on the surfaces of flaggy
sandstones, but the most abundant repositories are the beds which
I have named ' calcareo-bituminous shales' and ' bituminous lime-
stones,' beds which, on account of their superior toughness and
black colour, often stand out prominently in the coast-sections, and
are sometimes almost entirely composed of these shells.* As none
of the properly marine species of the Carboniferous Limestone ever
occur in theto beds, and as they are closely associated with the coal-
seams, I have always been greatly interested in them — in connexion
with the various theories of the deposition of coal. I referred to
them in this relation in ' Acadian Geology,' 2nd ed. 1868,'* in the
following terms : —

" All the lamellibranchiate shells, which are so numerous in some
of the shales and bituminous limestones of the Joggins that some
of the beris nay be regarded as composed of them, belong to one
generic or family group. They are the so-called Modiolas, Unios,
or Anodons of authors. I proposed for them, some y^^ars ago,
the generic name of Naiadites,^ and described six specie^ ^rom
the Coal Measures of Nova Scotia, stating my belief that they are
allied to Unionida), and that their nearest analogue may be the
genus Bysso-amdonta of D'0:bigny, found in the river Parana.

' ' Acadian Geology,' Suppl. 1st ed., 18G0.
'^ Quart. Journ. Geol. Soc. vol. xlix. p. 245).

^ See sectic of the South Joggins, iu ' Acadian Geology,' 2nd and later
editions.

* Pp. 202, 2U.i.

^ ' Aeudiini Gi-ology,' Suppl 1st txl. ,

43G

81K J. W. UAWSON ON NAIADITES IN

[Aug. 1894,

Mr. Saltei', however, to whom I sent specimens, regards these shells
as belonging to his new genera Anthracomya and Anthracoptera, the
former being supposed to bo allied to Myad<e.' More rece.itly
Giimbel and Geinitz have described similar shells from Thuringia
as belonging to the genera Unio and Anodon, and regard my Nain-
dites carbonnrius (Anthrcicojttem carhonaria of Salter) as a DrelssenaJ'
In the present uncertainty as to their genuine relations I shall retain
the name Naiadites for the whole of the species, givi; g, however,
Salter's generic names in brackets/'

In correspondence with Mr. Salter at that time, I had jwinted out
that these shells were probably freshwater, and objected to his
name Anthracomya as expressing an incorrect view of the affinities
of the shells that I had sent to him ; assigning the following among
other reasons, afterwards published in 1868 in a new edition of
'Acadian Geology' along with descriptions and figures of the principal
species, seven in number : —

(1) Under the micrcscopo those shells present an internal lamel-
lar and subnacreous layer, a thin layer of prismatic shell, and an
epidermis, all corresponding to similar structures in the Unionidfo.

(2) The ligament was external; there seem to have been no teeth.
The shell was closed (or slightly open) posteriorly, and in some
species there are indications of a byssal sinus. The general aspect
is in some species that of Unio, in others that of Mytilus. The
wrinkling of the epidermis seems to be, for the most part, an effect
of pressure.

(3) I know of no instance of the occurrence of these shells in
the marine limestones, or associated with species unquestionably
marine.

(4) The mode of their occurrence precludes the idea that they
were burrowers, and favours the supposition that they were attached
by a byssus to sunken or floating timber.^

(5) The attachment of Spirorbis to the outer surface of many
specimens seems to show that they were free in clear waters.

On these grounds, and being unable fr 1 the specimens in my
possession to make out evidence of generic distinctness, I continued
to use the name Naiadites in preference to adopting the newer
names Buggested by Mr. Salter. Under this name I have described
seven species from the Coal Formation of Nova Scotia, and have now
sent specimens of these to Dr. Wheeltou Hind for examination and
comparison.

I may add that I do not object to the division of the spociee into
two or more genera, for one of which Salter's name Anthracoptcra
should be retained. I doubt, however, whether these can be distin-
guished by form alone, which in most cases is all that we have

' Quart. Journ. Geol. Soc. vol. xix. (1863) p. 80.

^ Neuee Jahrb. 1864, pp. 646, 651, and Geol. Mag. 1865, p. 204.

' Dr. Hind informs me that a specimen iji the British Museum (Nat, Hist.),
at South Kensington, has the byssus preserved. [This specimen consists of
a piece of fossil wood, round which numerous individuals of Anthracojitera arc
clustered in several rows, as they would be if attached by a byssus. — W. H.]

Vol. 50.]

THE COilL-FORMATION OF NOVA SCOTIA.

437

to depend upon. The species s^cm also to have been very variable,
and they present very different appearances in different states of
compression.

I may also mention that Dr. Wheelton Hind has been led into
an error in supposing that Estliena Dan ^oni, described by Prof. T.
Ilupcrt Jones, E.R.S., in the Geol. Mag. for 1870, may be the same
with my Naiadites lams. These shells are quite distinct in forms,
markings, and structure, and occur at very different positions in the
Carboniferous. N. hrvis has been found only in a flattened state :
its epidermis is sfrong and wrinkled, and the shell shows traces
of prismatic structure.

The associates of Naiadites in the admirably exposed sections of
the Nova Scotian coal-field, at the South Joggins and Sj'dney, Capo
Breton, are various species of minute bivalve crustaceans, Eury-
pterids, Antlirapalcemmi,^ scales and teeth of ganoid fishes, and
Spirorhis, The beds also hold much carbonaceous matter and
fragments of fossil plants, often with Spirorhis attached. In some
cases the beds of Naiadites-^halc form the roofs of small coal-seams.
In a few they have been elevated into soils and have been pervaded
with Stir/maria-Toots, thus resembling underclays. Their whole
conditions point to land-locked ponds or lagoons, or to sluggish creeks.
From the continuity of the beds these would appear sometimes to
have been extensive, and, in addition to the animals already referred
to, they were visited by ganoid fishes of large size, of tho genus
lihizodus, and by small sharks of the genus Diplodus (Orocanthus).
They were also tenanted by tho aquatic batrachians of the period.

As the supposition that the shells of Naiadites were marine
has placed them out of relation with their associates in the Coal
Formation of Nova Scotia, it is a source of gratification to me, and
an important contribution to the theory of coal, that their true
affinities have now been so ably illustrated by Dr. Wheelton Hind.

Appendix.

Through the courtesy and kindness of Sir J. William Dawson I have
been favoured with a perusal of his ' Note on the Genus Nairdites^
and have carefully examined at his request a series of shells from the
South Joggins, as well as a series from the collection of the Geological
Survey of Canada, forwarded to me for that purpose.

From an examination of these specimens it is easy to understand
Sir William's attitude in considering it impossible to discriminate
with any certainty between the different genera of shells in the
South Joggins coal-field. They were all more or less crushed in the
shale, and therefore showed no interiors, and often the proper
external characters were masked. I am quite of the opinion now,
from the knowledge I have obtained by a long familiarity with
nearly perfect forms, that the genus Naiadites contains three distinct
genera, for one of which the name must be retained. These three
genera are the Fame as those which generally occur in our Coal

' A. Hilliana. Grol. Mag. 1877, p. r)C>.

438

DR. IVHEELTON HIND ON NAIADITRS IK [A.Ug. 1 894,

Measures, a fact wliich was recognized by the late Mr. Salter, who,
in a description of Sir William Dawson's shells, Quart. Journ. (Jeol.
Soc. vol. xix. (1863), substituted the names of his nowly-erocted
genera Anthnicoptera and Anthracomya for Naiaditcs, notwith-
standing the critical objections raised by the author of the name
Naiadites.

I have been in correspondence with Sir William on the subject,
and propose to retain the name Naiadites for the form called
Aiithracoptera.

In my paper published in this Journal, vol.xlix. (1803), p. 249, 1
figured and showed that Salter's Anthracoptera had a striated hinge-
plate, a character, the absence of which had been considered to
separate the genus MyaVma (Be Koninck), and in Ueol. Mag. 1893,
p. 514, I published a note on Myalina crassa, pointing out that
there were no anatomical features by which the shells known by
that name could be .separated from Salter's AntJiracojdera, at the
same time noting that the septa within the beaks described by
De Koninck were absent. On looking up De Koninok's original
description and figures I find in 1842 (' Descript. des Animaux
Fossiles,' p. 125) the following description : — " A Tintericur et
immodiatementau-dessousdo ceux-ci [the umbonos], une jjetite lame
septiforrae, scmblable a celle (]ue Ton observe dans certaines cspeces
de Mytilus." The figure given is too imperfect to shoAv these
characters. In his more recent work, ' Faune du Calcaire Carboni-
Icre,' ^ he describes the genus and says it is " muni d'une cloison
intt'rieure," but the figures, especially figs. 5, 7 and 1), pi. xxix.,
demonstrate most conclusively that this septum did not exist in
them.

Prof. King (' Permian Fossils,' pi. xiv. figs. 5, 7 »&; 12) shows
shells from the Permian which appear to possess this myophorial
septum, to which he gave the names Mytilus sqnamosiis and M.
sejjfifcr, but in the text he suggests their reference to De Koninck's
genus.

M'Coy (' Brit. Palaeozoic Foss.' p. ■^.92) says, in his description of
Myalina, that there is " a triangular septum in the cavity of each
beak, parallel with the plane of the lateral margins, leaving deep slits
under the beaks of the cast," but he mentions no specimens from
the Carboniferous series. When in the Brussels Museum a few
months ago I was unable to see any signs of the septa in De
Koninck's specimens, and think it probable that many of his forms
will have to be placed with Naiadites, the name Myalina being
retained for the septiferous forms from the Permian, and for any
which may appear in the Lower Carboniferous series,

[It has been thought advisable, at the suggestion of the Council
and with the assent of the author, to incorporate here the f Dllowing
synonymy of N^aiadites. — En.]

Ann. ITist. Nat. Musro roy. do liolpiquo, vol. xi. 1885.

Vol. 50.]

VnE COAL-FORMATION OF NOVA SCOTIA.

439

1840.
184;'..

184;-..
IH;->(J.
1853.

1854.

1855.
18(50.

1801.

1802.

Sywonymy OF Naiadites,

Naidea, Swainson, for r'?uo-like molluscs.

Ncr'^-n, Buckinan, ' Geology of C'heltenliam,' Rhactic and SlonesfiolJ
plants.

Naiadita, Brodie, Fossil Plants (in ' Fossil Insects').

Naiadita, Buckmaii, adopted in Quart. Journ. Qeol. Soc. vol, yi. p. 415.

Uawson figured several Molluscs from Nova Scotia resembling Modiola
and Unio, Quart. Journ. Geol. Soc. vol. x. (1854) p. 39

Naiadites, Morris, for Naidea and Naiadita, in his ' Catalogue of British
Fossils.'

Dawson again figured one of these molluscs a3 a Modiola, 'Acadian
Geology,' l.st ed. p. 148.

Dawson gave a short description of the shells and referred to the above
figure, provisionally naming it Naiadites. He described also several
species ; the first and tyjie species being Naiadites earbonarius. Sup-
plement to Lst ed. ' Acadian Geology,' p. 43.

Salter gave the name of Anthracomya to certain British Coal-measure
molluscs with full descriptions and figures, Mem. Geol. Surv., ' Iron
Ores of Great Britain,' pt. iii. p. 229.

Salter speaks of three species of Naiadites he had received from Dr.
Dawson, namely Naiadites dongatus, N. carbunariiis, and N. leevis.
The first and last of these he refers to Anthracomya, and for the other,
iv. earbonarius, Dawson's type, he proposes the name " A/ithracoptera
for these triangular shells."

If the name of ' Naiadites ' can be retained for any of these
molluscs it must be for this type-species N. earbonarius, for which
Salter erroneously proposed the generic name of Aiithracoptera,Q,uart.
Jouru. Geol. Soc. vol. xix. (1803) p. 80.

Note. — Wheelton Hind, 1893 (see below), says that the form figured
by Salter, Qi"irt. Journ. Geol. Soc. vol. xix. p. 79, fig. 3, as Anthrucoptera
carbona.'ia is not the same as Dawson's type, ' Acadian Geology,' 1st
edit. p. 148, and Quart. Journ. Geol. Soc. vol. x. p. 39.

& 1878. Dawson gives figures and descriptions of these Nova Scotian sheila
and partially adopts Salter's names as sub-genera for some of the
species, thus: Naiadites (Anthracopfcra) carbo?iaria, Naiadites (Anthra-
comya) clovgata, Naiadites (Authraeoptcra) Itevis ; but speaks against
Salter's idea of the marine nature of these shells (as quoted above,
p. 430), 'Acadian Geology,' 2nd & 3rd edit. p. 202 et seqq.

Wheelton ITind adopts Salter's two genera Anthracomya and Anthru-
coptera, ,jr the British species, but says that the specimen from
Nova Scotia figured by Salter as Anthracoptera carbonaria is not the
same as Dawson's Naiadites earbonarius ; the latter, Hind says, is
an Anthracomya, Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 249.

Wheelton Hind in tiie MS. of the present paper proposed to adopt
Naiadites for Anthracomya, and to retain the name of Anthracoptera
for the type-species of Naiadites. He now acknowledges that Salter's
Anthracoptera carbonaria is the same as Dawson's Naiadites earbo-
narius. The genus Naiadites, therefore, will have to be usctl and
Anthracoptera discarded. The British forms referred to the latter
geuus, in the author's 1893 paper, will now be called Naiadites.

I must admit the error of which I am convicted by Sir William
Dawson — namely, that I confounded Naiadites leevis and Estheria
Dawsoni — the more so as the fault was due to carelessness in com-
paring the numbers of quoted pages.

I am not able to state that any of the species submitted to me
are the same as British forms, therefore the specific names must
still remain, though, if at any time in the future more perfect
pppcimcns an^ nbtaitinblo. it may bo quite possible to do so.

18(i8

1893

1894

440

DR. WnEEr.TON niNI) ON NAIADITE8 IN [Aug. 1 894,

I have a aorios of spccimeiiH from the South Joggins hibolled by
Sir J. Williiitn Dawson Anthracoptera carhonarw. They existed
ill very largo iiutnbers in some of the shales of the South Joggins,
80 much so that the greater part of the mass is composed of debris
of this shell, with entomostiaea and vegetable remains. I have
little or nothing to add to Sir William's original specific description,
but would point out that his original ligure is very misleading, and
that jS'aiadites carho^nnnn, Dawson, differs much from the figure of
Anthracojtiera carlxmaria, Salter (Quart. Journ. Gool. Soc. vol. xix.
18(53, p. 79), and it was this difference which led me to suppose
that Dawson's original specimen was probably Anthracomya
(Quart. Journ. Geol. Soc. vol. xlix. 1803, p. 249). The umbones
were not shown to be terminal, and were described as " acute in
the anterior fourth of the shell," while I thought Salter's figure
was that of a specimen of one of his Anthracoptera'.

I am bound to say that Salter's figure more nearly represents
the shells which have been sent to me as Kaiadites cnrhonarius. In
shape this form approaches somewhat to that of Naiadites {Anthra-
coptera) modiolaris, but the umbones are more raised above the
hinge-line, more pointed and not curved anteriorly at the apex.

There is one s})ccimcn which reveals a typical interior with
finely striated hinge-plate, bevelled at the exterior of its outer edge,
with trifid anterior mnsculir scars, and relatively larger posterior-
adductor scar. The posterior end was often sinuated above. The
periostracum shows the typical characteristics of the genus. There
exists, as with us, an elongated form, probably only a variety of
this shell ; but it evidently comes from a different bed, the matrix
being a hard, fine-grained, micaceous sandstone (PI. XX. fig. I). It
would seem to have been less gregarious in its habit, if one may
judge from the paucity of its remains in the specimens to hand.

It is very difficult to be absolutely sure as to the generic position
of the shells figured as Anthroconii/a elongaia, as there arc no
specimens showing the hinge-line, ligament, or muscle-scars, but
from the shape they probably belong to this group. There is
nothing to add to the original description, but I think that the sen-
tence describing the position of the umbones is misleading. It says,
" the beaks obtuse an*' more anterior," but it is difficult to see what
is the meaning of the word more.^ It cannot refer to the shell
previously described, which is a Naiadites {Anthracoptera) carbo-
narius, and has its umbones very forward ; while, comparatively to
the length of the hinge-lino, the umbones in iV. elon,^atus are sub-
central in the specimen figured.

There appear to have been two forms or varieties of this shell,
one more elongate and comparatively narrower, the other short and
as broad as long.

With regard to Anthracomya arenacea, the specimen which
Sir J. W. Dawson has sent me is typical of Salter's genus ; it is
allied to the forms found on the Continent, and known as Anodonta

f A plpi-ical m-or for ' less.'— J. W. D.. Mht 1804.

Vol. 50.]

THE COAL-FORMATION OF NOVA SCOXrA.

441

Ooldfimiana. Tho original drawing in ' Acadian Geology ' does not
8ho\v tlio gradually oxpamling jiosterior end, and would give tho idea
that the original was an Anlhmcosia. I think the specimen from
tho McUiU College Collection labelled Naiadites elongatus belongs
to this species. This specimen is nearly 1 inch long, and shows tho
typical shape and contour.

Naiadites angulatus (Dawson) I considor to be \ inthmcosia

a pretty little form of typical shape. In the original drawing tho
posterior-superior angle is too much prolonged backward.

Anthracomi/a ovalis is a somewhat larger, more tumid shell thiiu
Naiadites eloiu/atus, to which it approaches. I think that the shells
in a block of Millstone Grit from Riversdale belong to this form ; if
so, it is interesting to note the presence of the same form in tho
Upper Coal Measures of the Joggins.

Anthracomj/a la-vis is very similar to a shell which is obtained,
only crushed flat, from the Wigan coal-fteld ; tho English specimens
are, however, larger.

Prof. Amalizky has fallen into error as to the value of the term
Naiadites, and in his work on the Anthracosida) of the Kussian
Permian, 1892, has erected Naiuditts into a genus of tho new
family Anthracosida3, resemng the term for a set of shells totally
different from the majority of those for which the name was
invented. I have shown above that originally the genus included

Naiadites carhonariiis.

„ clongattis.
Anthracomya arenaeea.
„ ovalis.

Anthracomya Uevis.
f Carhonicola 1 , .

[Anthracosia\'"'y''''-'*'''

I shall take an early opportunity of combating other views on
this subject contained in Prof. Amalizky's work.

EXPLANATION OF PLATE XX.

Coal-Moaaure shells from the South Joggins. The figures are of the natural
size, when not otherwise stated.

Fig. 1. Naiadites, B\-i. Elongate form. (Unfortunately tho artist has inverted
tho figure.)

2. Naiadites carbonarius (Dawson).

3. „ „ showing interior. Muselo-pits.

4. Anthracomya arenacea (Dawson).

5. „ ,, probably young.
fi. „ „ probably young.
T. Anthracomya cloncfaf a (Davrson). x2.

O. ,, M II X—.

9y 2
• M II II /N *^'

10. „ „ „ X2.

' It is highly probable that the term Anfhracosia, King, must give way to
Carbonico/a, M'Coy, on the grovmd of primnty, although the hit tor's description
of the hinge-plale is erroneous.

442

NAIAD1TE8 FROM NOVA 8C0TU.

[Aug. 1894.

Fig. 11,

12.
13.

14.

Slub with (a) Aiithrncomya elongata,
(h) Anthracomi/a, sp. ?
(e) Naiaditca carhonarina,
(Collection of tbo Gcol. Survey of Oaimda.)
Anthracomt/a hevin (Dawson).
Anthracomya ovafin (Dawson). Horizon of tlio Millstone Orit.

1 Anthvdcosia (King5 | «"•'/«'«'« (Dawson).

[Note.— Sj)(Timen.s 1, 4, .") belong to Sir J. W. Dawson's coUeotion in llie
Mc'Gill College, Moiiireal ; .8l»ec-iineiiH 11 & 13 t() tiio Oeologioal Survey of
Ounatbi. Tbe rcnminder liavo been presented to uio bv Sir J, W. Dawson.—
W. H.l

Quoirt. Joum. Geol. Soc . Vol, L , PI . XX.

'i0fi^->*iV ', ,1 ''n

A.HSearle del.et:iit.-

Mir^tern Bros. intp.

:'.,>vLrMf:ASUFii-: shf:ll,s krOxM: tiik south joguINo.