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FACING PAGE

Chalk Polyzoa : : : : : 5 ; t 4

Interior of Peristome in Conuwlopsis, Hchinocorys, and Echino-
ence

Casts of Shells from the Suffolk Boxstones j : 5 ay 20.

cardvum

ae » » 30 2 ¢ 6) all
Hocystis prumeva, Hartt . : : : : ; ; 5 oS
Chalk Polyzoa é 5 : 6 : c : 9 - 100
Land-forms, Carnaryonshire . : : : s A ors
Tertiary Foraminifera, New Guinea . ¢ : : ; 5 Pla

2 05) sh peed teaean OV Sans ann east a Gn
George J. Hinde, F.R.S. . ; : 6 ‘ 4 , 5) 33s}
Leicestershire Dolomites . é : : ; : 9 - 258
G. W. Lamplugh, F.R.S. : é : : . 5 9) eat,
Leaves of Noeggerathiopsis ; 3 ; é : : 292,
Great Erratic of Andesite, New Zealand . ; é : 5 BOT
1B in Newell Arber, M.A., Sc.D. . He A is Bs aie: PAG)
British Carboniferous Goniatites ; 6 é : : . 450

Post-Larval Stages in Irregular Echinoidea ; 5 : . 500
Basic Intrusions in Radnorshire 3 : . : ; . 502

Diabase intruded into Llandovery Limestone . 6 : . 504

LIST OF ILLUSTRATIONS IN THE TEXT.

PAGE
Diagrams of perignathie girdle in Plesiechuis, ete. ; : : Ul
Diagram showing lines of mechanical stress Dan of Hoey ets plan
of plate . : : f : : ait ieee
Diagram map of §.W. aneolnenive. saGuine Nation of exposures i O4
Hydraulic limestones of Owthorpe and Cotgrave Gorse . ; ; BO:
Transition bed and Middle Lias of Lincoln . : 105
Middle and Upper Lias of Yorkshire, Lincolnshire, and } Nena tonetne 109
Diagram of Northampton Sands and Upper Lias_ . : : : 3 TAG
Sections of Newark District, Nottinghamshire é : : ¢ 2) 22
Profile of land surface near Tregarth : : > : . a) ALSO)
“*Pliocene’’ plateau near Bangor . : é : : : : . 154
Shell-fragments deseribed as Cirripede valves . : : : : 3
Drawing of deer from cavern of a Pefia : : 5 . : . 173
George Jennings Hinde, F.R.S. . : \ : : : ; + 236
Map of Leicestershire dolomites . 5 : é 5 : : . 252
Bouchardia minvuna, Thomson . 5 : : A : ; . 260
Phreatoicus australis, Chilton i 3 : : ; p : 278
Phreatoicus wianamattensis, Chilton . ; : ; i : a Bag)
Map of part of the London Basin . c : a ASKS:
Map showing contours of Sub-Hocene and Sie Bien Chalk : ea 02
Section across part of the London Basin 3 j j : : . 304
Map of principal ‘dry ’’ lakes, Western Australia . : j } 3 UY
Locality map of southern portion of Western Australia . é ‘ 4 Bul)
“Downend Chalk Pit’? on Gallows Hill, Isle of Wight . : F 5) B58}
William Lower Carter, M.A., F.G.S. |. ; 3 i A ; 5 ase
Map of Western Ausiralia.. : s ‘ : . 386
Sketch-section of the Darling Range, eon Mastin ; 3 4) BIS)IL
Sketch-map of Lenham Bed, Diestien Sands, Louvain . : ‘ . 41L
Map showing Chalk surface contours, Hast Anglia . ‘ 2 Y . 414
Calcite cleavage . tl : f i , . 424
Crustacean tracks in } New vediena Mertianies ‘ : : : . 425
Anthracomya arenacea, Dawson . : 5 5 : f : - 465
Huproops Amie, H. Woodw., sp. nov. . ‘ . : 3 : . 466
Head-shields of Huproops Amie, H. Woodw. 4 : : : . 467
Bellinurus Trechmanni, H. Woodw., sp. nov. ; ; d t mae Asiale
Section of nodule showing plant-tissues . : 2 : : 5 . 472
Yunnan Cystidea . ‘ : : 4 Fi : } 508, 509, 534, 535
Hyana salonice, n.sp. . 5 A i ; 4 4 Sy Syl
Map showing mineral resources of iduivalia 545

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ORIGINAL ARTICLES.

RCT
J.—NoTES ON NEW OR IMPERFECTLY KNOWN Cretaceous Potyzoa.
By R. M. Brypone#, F.G.S.

(Continued from the November Number, p. 496.)

(PLATE I.)

ICARIOUS avicularia, that is to say avicularia ational as
large as zocecia, have rarely been figured among the Cretaceous
Cribrilinide, the only good instances I call to mind beine Escharipora
inerassata, D’Orb.,! Membraniporella ( Cribrilina) Faleoburgensis, Perg.,*
the illustration ‘of which shows a clear case, although no reference is
made to it in the text, and Cribrilina ostreicola, Bryd.* They are
not, however, by any means so rare as this might suggest, and the
four following species are probably not the only instances which will
ultimately be added from the English Chalk.

MeEMBRANIPORELLA ALTONENSIS, sp. nov. (Pl. I, Figs. 1, 2.)

Zoarium unilaminate, adherent.

Zoecia small, average length °45 to °5 mm. (exclusive of
ocecium)) ; side araills prened slightly inwards, front walls arched,
arising without apparent break from the edges of the side walls and
pierced by six pairs of radiating slits reaching from the edges nearly
to the middle line; aperture semicircular, very simple, the posterior
lip being apparently unthickened.

Oncia occurring very regularly, helmet-shaped, with apertures
cut well back.

Avicularia vicarious, with vaulted blister-like external walls;
apertures shaped like a thermometer tube, with round bulb and
straight stem ; there is no raised rim round the bulb, but as it passes
into the stem rims arise rapidly on either side and enclose the whole
length of the stem, opening out into a small circle at the anterior
end to admit a narrow internal front wall; as the surface of the beak
is horizontal it stands out increasingly as the surface of the external
wall descends anteriorly. Sometimes the beak is covered by an
imperforate membrane. This species occurs very rarely in the zone
of H. planus near Alton, Hants.

MeMBRANIPORELLA SHawrForpensis, sp. nov. (PI. I, Figs. 6, 7.)

Zoarium unilaminate, adherent.

Zowcia of medium size, average length *58 to °62 mm.; the normal
surface is obviously largely secondary; I have not seen any certain
Pal. Crét. Franc., v, p. 223, pl. 685, figs. 2, 3
Bull. Soc. Belge Geol., 1893, p. 176 et seq., text-fig. 7.

GEOL. MAG., 1909, p. 399, Pl. XXIII, Figs. 1, 2
DECADE VI.—VOL. V.—NO. I. 1

pep aie!
;

Deets Brydone—New Cretaceous Polyzoa.

instance of the primary stage, but it is probably represented in
Fig. 7, and consists of zocecia with distinct bluntly pyriporiform
side walls, flatly arched front walls, pierced by five pairs of well-_
marked slits extending from the edge about a third of the way
across, and a flatly semicircular aperture with slightly concave and
upturned posterior lip formed by the broad unthickened margin of
the front wall; the anterior end of the zocecium rests on the rising
external wall of the succeeding zocecium, and thins out against it ;
small distinct avicularia are lodged in the interzocecial depressions ;
in the secondary and normal stage the posterior lp of the aperture
thickens and fuses completely with a pair of avicularia at the corners
of the aperture and extends backwards a little way over the front
wall in a blunt triangle and forwards on either side of the aperture
on to the sides of and round the ocwcium so as to form a platform level
(except for the swelling due to the ocecium) and standing only
slightly above the front wall in the middle line, but considerably
above it at the sides, and encroaching on it more or less all round,
but especially at the posterior end; the result of this encroachment
is that only three of the pairs of slits usually remain visible and
then only in reduced length; there is generally more or less of
a depression in the centre of the anterior lip of the secondary
aperture.

Owcia invariably present in the secondary condition and evidently
highly globose, but without any definite outline; aperture sunk
below the general surface, so that its free edge is only partially
visible.

Avicularia.—(a) Vicarious, average length °55 to *6mm., scoop-
shaped with approximately parallel side walls and rounded ends;
the aperture appears to be bounded by the side walls in the posterior
part, but anteriorly it tapers away and a narrow internal front wall
appears; there are remains of a transverse bar across the posterior
end of the aperture; they occur rather freely along the edge of the
zoarium, and not infrequently in the body of the zoarium, where
they are deeply sunk. (4) Accessory, in the primary condition
apparently beak-shaped and distinct; in the secondary - condition
wholly merged in the general mass, leaving only the broadly arrow-
head-shaped apertures visible; a pair occur very regularly at the
posterior corners of the aperture and another pair much less
regularly at the anterior corners.

This species is very rare; I have only seen one specimen, from
the zone (restricted) of 4. guadratus at Shawford, Hants. But for
its vicarious avicularia it would form a very perfect link between
Membraniporella subcastrum, Bryd.,' and I. castrum, Bryd.?

MEMBRANIPORELLA BEDHAMPTONENSIS, sp. nov. (Pl. I, Figs. 3-5.)

‘Zoarium unilaminate, adherent.

Zoecia distinct, average length °65 to "7 mm.; side walls strongly
overarching, front walls arising within the edges of the side walls,
flatly arched and pierced by five or six pairs of very short, often

1 Ante, p. 494.
? GEOL. MAG., 1909, p. 398.

WES A ae ‘iba

ORM. Brydone—New Cretaceous Polyzoa. 3

wide, and even triangular radiating slits; aperture horseshoe-shaped,
posterior lip formed by the broad unthickened shghtly upturned
margin of the front wall, and uniting with the anterior lip to form
a thin subtubular peristome.

Oecia occurring freely but very erratically, relatively small, with
rather narrow apertures cut slightly back.

Avicularia.—(a) Vicarious, average length -6mm., with beaks of
the hour-glass type, but scoop-shaped, with almost parallel side
walls hardly folded over or constricted at all in the middle or
expanded at the ends; the posterior end of the beak is tilted up on
a strongly inflated external wall; the aperture is long and narrow
with rounded ends, the posterior end being bluntly rounded and
enclosed by a very narrow internal front wall, and the anterior end
tapering somewhat and being enclosed by a wide internal front wall.
(6) Accessory, small roundish lumps with arrowhead - shaped
apertures standing up high and possibly sometimes supported on
slender legs like those of I, Sherbornz, Bryd.’; very abundant,
grouped thickly round the apertures, sometimes as many as four to
an aperture, but very rare away from the apertures. ‘The vicarious
avicularia are very erratic in occurrence, and do not seem to appear
until the zoarium has reached a fair age, so that they can only be
expected at the edges, if at all, in small or medium-sized zoaria.

‘This species seems to be coeval with JZ manonia, Bryd.,? and like
it very characteristic of and restricted to the lower part of the zone
of B. mucronata in Hants and the Isle of Wight.* It has been found
at the very base of that zone at Bedhampton, Hants, but never yet in
the zone of A. quadratus. It forms avery natural introduction to

Mempranrporetta Trimensis, sp. nov. (Pl. I, Figs. 8-10.)

Zoarium unilaminate, adherent or free.

Zoecia large, average leneth °9 to -95mm., distinct, decidedly
pyriporiform ; front walls arched, arising at an angle from the edges
of the side walls, and pierced by about four pairs of short, broad,
and sometimes triangular slits, with a broad band separating the
uppermost pair of slits from the aperture and merging at its ends
imperceptibly into the side walls; aperture typically about five-
eighths of a circle, with a short, straight, posterior lip, but rather
variable in shape; posterior lip short and straight with a slightly
upturned edge, which sometimes develops into a median denticle,
and combines with the anterior lip produced upwards and slightly

1 Tbid., 1906, pp. 289-300, Fig. 7 (as Cribrilina Sherborni).

2 Ante, p. 146.

3 There is a very similar form in the Weybourne Chalk, in which according
to my only good specimen the front wall has the slits usually obliterated by
calcification, the aperture is very irregular in shape and sometimes sharply
triangular owing to the encroachment of the accessory avicularia, the
accessory avicularia are only slightly prominent, and the vicarious avicularia
are longer and wider and expanded at the anterior end, being of the same
general outline as those of Membranipora invigilata, Bryd. (GEOL. MAG.,
1910, p. 76), and the remains of the transverse bar are much more pronounced.
I should not care to commit myself to its being a distinct species on practically
one specimen, but if so it might be named M. Weybournensis.

4. Herbert L. Hawkins—Studies on the Echinoidea.

Eorwardé: into a thin subtubular peristome. There is a tendency for
a roof to arise along the interzocecial furrows and spread over the
posterior ends of the zocecia.

Owcia very scarce, large, and very globose; aperture niantow,
vertical. ay

Avicularia.—(a) Vicarious, very large, up to 1 mm. in length, of
hour-glass type, with very round anterior ends and side walls sloping
outwards in the middle; apertures rounded posteriorly and almost
pointed anteriorly, with a large area of internal front wall in the
anterior bulb of the hour-glass and a considerable amount in the
posterior bulb; there is athick transverse bar just below the area of
constriction. (6) Accessory, small beak-shaped or rounded masses
raised above the general surface apparently on slender legs as in
M. Sherborni, Bryd. (ante), and scattered in great abundance along
the interzocecial furrows, while sessile specimens encroach very freely
on the broad posterior lip of the aperture.

This very fine species occurs sparingly in the Trimingham Chalk.

EXPLANATION OF PLATE I.

(All figures x 12 diams.)
Fic. 1.—Membraniporella Altonensis. Zone of Holaster planus, near Alton,

Hants.
nema Die aa 5 Another part of the same specimen
showing closed ayicularia.
Meaney ap Bedhamptonensis. Zone of B. mucronata, Bed-

hampton, Hants. From the
margin of a large zoarium.

At ae ae sh Part of the interior of the same
zoarium.

er O}s Ke a Part of a zoarium in which no
avicularia have developed.

5H Oa dla Be Shawfordensis. Zone of A. quadratus, Shawford,
Hants.

», 8-10. ae Trimensis. Zone of B. mucronata, Trimingham.
Different parts of the same
zoarium. No. 10 shows an
oecium slightly confused
with a perfect avicularium.

IJ.—Monrenonoeican Sruprrs on THE EcHINOIDEA HoLecrypormDA AND
THEIR ALLIES.

By HERBERT L. HAWKINS, M.Sc., F.G.S., Lecturer in Geology, University
College, Reading.

VII, Tue PeErienatuic GirpLe or tHE HoLncryporpA AND THE
CorRESPONDING SrRucTURES OF orHbR IRREGULAR EcHINOIDEA.
(PLATE II.)

1. InrRopuction.

N the three preceding papers of this series descriptions have been

given of the perignathic girdles of familiar representatives of the
three families into which the Holectypoida are at present divided.

Grou. Maae., 1918. Pratt I.

R. M. Brydone, Photo, Bemrose d: Sons Ltd., Collo.
Chalk Polyzoa.

Herbert L. Hawkins—Studies on the Echinoidea. 5

From the scanty evidence available, it would appear that in respect
of this structure Plestechinus is typical of the Pygasteridze (even
including Anorthopygus). The girdle of Holectypus seems essentially
similar, thereby differing from that of the Discoidiine; but as yet
the perignathic structures of the Cretaceous Coenholectypus are
unknown. Large species of Discoides have girdles differing in
proportions only from those of the smaller forms, typified by
D. subuculus. In default of further knowledge, the development
of the girdle in Conulus albogalerus may be considered to be that
characteristic of the genus and family. It is thus possible to
summarize the known features of the girdle of the Order with some
confidence, and to discover the ‘‘ common denominator”’ of its varied
characters. Stripped of its diverse additions, the girdle is found to
present a uniform and practically unvaried structure which may be
regarded, from the systematic standpoint, as being a diagnostic
feature of the Order.

The primitive and conservative nature of the Holectypoida among
Trregular Echinoids has been so often indicated, and indeed is so
manifest, that it may be taken for granted without further argument.
It follows from this that there are but two alternative possibilities
for the lines of descent of all other Orders of the Sub-Class. Hither
they must have arisen from some ‘‘ Regular’’ stock independently
of the Holectypoida, in which case they need show no special
resemblances to that group save under the influence of parallelism of
development; or else they must have descended directly or indirectly
from Holectypoid ancestors. In the present paper a brief description
of the peristomial characters of certain representative Irregular
Eehinoids is given, and an attempt is made to indicate the presence
or absence of relationship to the Holectypoida shown by this fragment
of evidence. The genera whose internal test-structure has been
examined for this purpose are Clypeaster, Echinocyamus, and Kchin-
arachnius among the Clypeastroida, Nucleolites and Trematopygus
amone the ‘‘ Nucleolitoida’’, Conulopsis among the ? Cassiduloida,
and ELehinocorys, Micraster, and Echinocardium among the Spatangoida.
In the case of the first and last mentioned Orders, the genera studied
may be taken as fairly representative of the groups to which they
belong; but the other two Orders (usually grouped together under
the name here restricted to the latter) are very imperfectly illustrated.
This is accounted for by the extreme difficulty of the preparation of
the Jurassic forms and the virtual impossibility, under existing
circumstances, of acquiring suitable material of the Cass¢dulus—
LEchinolampas series, which are almost unrepresented in the British
fauna, both past and present.

On stratigraphical evidence it is at least possible to regard the
Nucleolitoida (including such genera as Wucleolites, Clypeus, and
Pygurus) as “cousins”? or even ‘‘brothers”’ of the Holectypvida,
rather than as their lineal descendants. If this should prove to be
the case an interesting illustration of parallelism would appear. The
Holectypoida are first found in the Lias, occur in abundance
throughout the succeeding stages of the Mesozoic, and are represented
in the Tertiary and Recent faunas only by the apparently degenerate

6 Herbert L. H awhkins—Studies on the Echinoidea a

types of Hehinonéus and Micropetalon. The Nucleolitoida similarly
make their first appearance in the Lias, were extraordinarily abundant
and varied in the later Mesozoic, and are reduced at the present day
to a solitary and very simple representative of their least specialized
family, the Nucleolitide. ‘he time of the first occurrence affords no
indication of the ancestry of the other three Orders of Irregular
Kchinoids; and the approximate synchronism of their differentiation,
while suggestive of a common origin, may well be but another
expression of the parallelism above indicated. Although evidence
derived from the study of one series of structures affords no sound
basis for the erection of a scheme of phylogeny, it is none the less
profitable to examine it as an index of morphogenetic affinity. If
the prevalent view of the irreversibility of evolution is correct, such
indications should at least show which lines of descent are ampossible,
and so narrow down the limits of probability, which may be further
restricted by similar arguments founded on the observed characters
of different sets of structures. It will be in this sense that sugges-
tions as to the phyletic affinities of the various forms studied will be
put forward in this paper.

2. THe Hotectrypor Greve.
(a) Lhe persistent elements of its structure.

Although the perignathic girdles of Plestechinus and Conulus appear
to be essentially dissimilar on a casual inspection, the reverse seems
to be the truth. Ifthe distinction between the ‘‘ true” and ‘‘false”’
ridges of the girdle, which I have argued in the two preceding papers,
is accepted, the differences between the characters of the “‘ genuine”’
girdle in the two genera prove to be of so insignificant an order that
they would hardly excite surprise if occurring in two species of
a single genus. The accompanying diagram (Text-fig. 1), in which
the three best-known girdles of the Holectypoida are associated
(together with the two chief types of Clypeastroid girdle), shows this
fundamental identity more clearly than verbal description could
suggest. In the diagram the buttresses and false ridges (where
present) are drawn in outline, while the true elements of the girdle,
both ridges and processes, are blocked in. The undifferentiated parts
of the corona are indicated by shading. The conservatism of the
Order could nowhere be expressed more emphatically than by the
retention of so physiologically important a structure throughout
the Jurassic and Cretaceous stages with hardly appreciable change.

The essential characters of the perignathic girdle of the Order
Holectypoida may be thus described :—

Ten lath-like processes spring in pairs from the proximal ambulacral
plates, and are inclined outwards from the vertical axis.. For the
greater part of their length the pairs diverge slightly (1.e. slope away
from the perradial line), but at their distal ends they may converge
to a small extent (i.e. Discordes), never sufficiently to produce even
the semblance of an arch or ‘‘auricle’”’. ‘he processes are supported
by variously placed and diversely developed buttresses, but are always
separated from these by a defined suture, and are composed of more
compact stereom.

Elerbert L. Hawkins—Studies on the Behinosden.

Five very small ridges occupy the inner
surfaces of the proximal (unpaired) inter-
ambulacral plates, never extending beyond
the limits of the latter. They are crescentic
in plan, have a various sculptured surface,
and are always separated from the processes
by a space at least as great as their breadth.
They may be entirely free (Plesvechinus), or

‘may become more or less involved in the,
buttresses when these tend to encircle the’

peristome (Discordes and Conulus).

These two sets of structures, according to
my belief, are the only ones concerned with
the attachment of the jaw-muscles, and so
constitute the true perignathic girdle. All
other structures entering into the ‘‘ peristomial
ring” are variously swollen portions of the
normal plates, adapted for the mechanical
support of the processes, the jaws, or the
buccal plates (or in some cases of all three
sets of ossicles), or for the greater strength
of the invaginated part of the corona which
encloses the peristome. The true perignathic
girdle retains very constant proportions from
Liassic to Upper Cretaceous times, its only
noteworthy change consisting of a progressive
tendency towards increased obliquity in the
setting of the processes.

The Holectypoid girdle, as thus restricted,
is extremely primitive. As regards the pro-
cesses, it represents a phase reproduced only
in the early post-larval ontogeny of recent
Diademoida, and there is some reason to
believe that the ridges of non-Cidaroid
Regular Echinoids are first developed on the
unpaired interambulacral plates. The in-
ference may be drawn that the Holectypoida
sprang from a Regular stock at a stage when
the perignathic girdle had barely progressed
beyond the early Cidaroid phase, and that,
unlike most of their Diademoid relatives,
they failed to improve upon the almost
phylembryonic structure with which they
were endowed.

(b) Zhe perignathic buttresses.

In all of the Holectypoida whose perignathic
girdles are known, the processes are supported
by buttresses which rise from the inner
surface of the test. These supports are
demonstrably parts of the actuai coronal

in outline, and the normal coronal plates shaded.

)

y, drawn on ‘‘ Mercator

B, Discoides; C, Conulus; D, Clypeaster; KE, Echinarachnius.
arious parts are not accurately shown, all the figures being brought to the same size.

(in B and C

‘ures represent the girdle viewed from the peristome laterall

Oo
f=)

.
‘)

1.—Diagrams of the perignathic girdle in A, Plesiechinus
The elements of the true girdle are black, the false ridges

The fi

Fie.

The proportions

’s Projection ’’.

of the vy

8 Herbert L. Hawkins—Studies on the Hehinoidew: =e

plates, being crossed by transverse sutures, and they can be
distinguished from the actual elements of the girdle by their less
polished surfaces and open stereom-mesh in direct continuity
with that of the plates from which they rise. In Jurassic forms,
and apparently in their nearest relatives in the Cretaceous period,
the buttresses are short and steep ridges which radiate for a varying
distance near to or upon the adradial sutures. In Discoides the same
series of radiating ridges can be recognized, although they are
reinforced by others oly similar trend and by a circular region of
elevation surrounding the peristome. In Conulus, where the whole
inner adoral surface of the interambulacral area is much thickened,
no separate buttresses can be distinguished; each area may, however,
be regarded as being lined by a fused and extended mass of
buttresses.

The apparently universal presence of this adambital support for
the processes is almost peculiar to the Holectypoida. ‘he girdles of
the Cidaroida and Diademoida are sufficiently strong in themselves
to stand without additional help; those of the Clypeastroida, though

often relatively slender, are so encompassed by the ridges and pillars
which cross the test-cavity that they seem to be equally independent,
in most cases, of special buttresses. This contrast 1s suggestive of
some special relation between the perignathic girdle and the jaws in
the Holectypoida wherein they differ from the other gnathostomatous
Orders. Perhapsit may be connected with the undoubtedly ‘‘ flaring ”
character of the lantern. In the Regular Orders the jaws are almost
vertical, and their weight can best be supported by a ‘‘sling” of
muscles, on all of which the ‘‘pull”’ would be almost vertically
downwards. In the Clypeastroida the jaws are practically horizontal
in typical forms, and they almost articulate with the processes. The
onus of their support will be shared between the adoral surface of
the test and the processes, the strain on the latter acting again
vertically downwards. But with a lantern inclined at, say, 45° from
the vertical (and a girdle correspondingly splayed), the downward
weight would tell upon the lath-like processes obliquely, so that they
would require to be strengthened from below and without to prevent
fracture. In support of this suggestion it may be recalled that in
those Clypeastroids in which the lantern is elevated above its normal
prostrate position, the processes have adambital keels similar in many
respects to those of Plesiechinus.

Although the buttresses are obviously, and probably originally,
connected with the mechanism of the perignathic girdle, they assume
a more far-reaching function in the Cretaceous Holectypoida and
their Clypeastroid descendants. The adoral regions of the test in
both Orders is normally very thin, so that the peristomial invagina-
tion, as well as the sharply reflexed ambital margin, demand a
girder-like support. In the Jurassic forms, the latter line of
weakness is not seriously developed, and the buttresses in conse-
quence are restricted to the central part of the surface, in the region
of the invagination of the peristome. In Discoides the ambital
margin is angular rather than curved, so that the girders are extended
across that fragile zone. In Conulus, although the ambitus may be

Herbert L. Hawkins—Studies on the Echinoidea. 9

as acute as in Drscotdes, the general thickness of the test makes
unnecessary the prolongation of such carinate buttresses. In the
Clypeastroida, where the angle between the adoral and adapical
surfaces of the test is often very acute (e.g. Hchinarachnius), a
bewildering profusion of essentially buttress-lke structures is
developed. It is worthy of note that in those Clypeastroids which
have a moderately rounded ambitus (e.g. Hcehinocyamus) the buttresses
are for all intents and purposes retained in the relatively simple
‘« Discordes-phase”’.

The buttresses may be considered to have been developed primarily
as supports for the inclined elements of the perignathic girdle, and to
have acquired a secondary function as joists, girders, or rafters for
the strengthening of the test-fabric. This secondary function is
retained, and carried to an almost excessive degree of specialization,
in the typical Clypeastroids, where the primary purpose of the
buttresses has disappeared, and their original positions are
abandoned.

8. Tue Cryprastroip GIRDLE.

It is unnecessary to describe in detail the well-known characters
of the girdle of the Clypeastroida. Students may be referred to the
exquisite drawings and detailed descriptions in Lovén’s Hehinologica ;
or, for a general summary, to Jackson’s Phylogeny of the Echan.

‘It will be sufficient here to indicate the analogies between the various
types of Clypeastroid girdle with that of the Holectypoida, and to
indicate the probable relations between them.

The Clypeastroid girdle seems to consist of processes only. These
processes are always approximated to one another in pairs near the
interradial line, and in many groups are fused into a single, though
often visibly compound, element. Their interradial convergence is
rendered possible by the reduction in width of the interambulacra
as they approach the peristome, and by the actual extension of the
ambulacral plates, whereby they sometimes meet internally across
the interradius, more or less completely ousting the proximal inter-
ambulacral plate from participation in the lining of the test-cavity.
The processes may, however, transgress on to the proximal inter-
ambulacral plate when this is well represented, this anomaly being
usual where the processes are fused.

In Lehinocyamus, a genus usually regarded as showing arrested
evolution, and approximating to the Discocdes subuculus group of the
Holectypoida, the perignathic girdle is found to be exceptionally
specialized. Superficially regarded, it certainly appears like that of
D. subuculus, especially since it is buttressed up by the thickening
of the interambulacral plates, and the floor of the test is traversed by
carine. But each section of the girdle consists of a fused pair of
processes which are based entirely on the interambulacrum. ‘There
seems every reason to believe that the girdle does actually consist of
transposed processes, but there is no proof of the existence of a ridge,
whether true or false, included between them. It is certainly
questionable whether such a development can be considered primitive,
in comparison with that of such a form as Clypeaster. Probably the

10 Herbert L. Hawkins—Studies on the Echinoidea.

two types of girdle characterize independent lineages. Echinocyamus .

(and the Scutellidz) may perhaps claim the small Dzscocdes as their
ancestors, while the genealogy of Clypeaster leads back through
Conoclypus to such a type as Duiscoides cylindricus.

The essential difference between the Holectypoid and Clypeastroid
girdles lies in the apparent absence of any originally interradial
element in the latter. This element is, however, so persistently
minute in the Holectypoida that its suppression would be a slight
modification when compared with other morphological changes
introduced in the Tertiary Order. In the Clypeastride, the virtual
exclusion of the interambulacral plates from the inner rim of the
peristome renders the change inevitable. In the Achinocyamus series
the fusion of the two transposed processes would tend to crush the
ridges out of existence, although it is at least conceivable that some
trace of them may remain in the middle of each compound ‘‘auricle”’
Except in the family of the Fibulariide, the neighbourhood of the
peristome is practically free from structures due to secondary
thickening, so as to allow free play for the recumbent lantern.
There is thus no reason nor opportunity for the development of
a false ridge. The processes of Clypeaster are upheld by carinze
recalling those of Plestechinus.

If the false ridges of Discoides or Conulus were removed (or laid
parallel with the floor of the test), and the already almost negligible
true ridges abandoned, the resulting girdle would be, for all intents
and purposes, that of the Clypeastride. Further knowledge of the
ontogeny of the girdle of the Fibulariide, Laganidz, and Scutellidee
is needed before a definite opinion can be formed as to the origin of
the interradially placed fused ‘‘auricle”. As far as appears at
present, this could have been produced either by the convergence of
the isolated processes of a Clypeastrid, or independently by an inter-
radiad encroachment of the processes of an Holectypoid upon the
ridges, resulting in the destruction or incorporation of the latter.
In any case it seems clear that both types of Clypeastroid girdle can
be regarded as modifications of that of the Holectypoida.

4. Tue Nocieortrorip PERIstome.

The following section is based upon an examination of twenty-seven
specimens of Vucleolites scutatus from the Corallian of Marcham, near
Abingdon, and of two examples of Zrematopygus from the Faringdon
Greensand. ‘These are the only forms of this Order in which I have
as yet succeeded in exposing the interior of the test. Serial sections
through the adoral regions of a specimen of Galeropygus agarietformis
and two of Clypeus sinuatus seem to show no serious difference in this
character from the smaller and more satisfactorily studied genera.

The greater part of the test of the adoral surface of most
Nucleolitide is very thin, and the peristome is markedly invaginate.
(An exception to this rule occurs in those forms which have the
beginnings of a floscelle developed.) Seen from within the peristome
it resembles a truncated and obscurely pentagonal hollow cone. The
interambulacral parts of the margin are quite obviously thicker than
the ambulacral, and than the rest of the adoral part of the test.

Sa GA pie ahd }
bed f

Herbert L. Hawkins—Studies a he Echanovdea: All

But this locally thickened region is merely arim, and no trace of any
structure even remotely suggestive of a perignathic girdle can be
detected init. Itis not undercut adambitally, but is imperceptibly
reduced to the average thickness before the invagination is passed.
The ambulacral part of the peristome border is remarkably thin, and
shows absolutely no indication of any kind of specialization. It is
simply the inverted edge of the proximal ambulacral plates. There
is thus no vestige of a perignathic girdle in the observed genera of
this Order.

The complete and sudden disappearance of the jaws and everything
pertaining to them in the Nucleolitoida is mysterious, but by no
means surprising. Before the advent of the Oolitic period, while yet
the Diademoida and Holectypoida had hardly entered upon the paths
of the evolution of their buccal structures, the Nucleolitoida had
utterly abandoned all traces of such apparatus. An ontogenetic
parallel is afforded by the young Hehimonéus, in which a lantern
and girdle are almost completely developed, both disappearing
simultaneously at a later stage of growth. In the absence of any
development capable of correlation with the perignathic girdle, it is
impossible to make comparisons between the Nucleolitoida and the
Holectypoida. But the complete diversity of the two Orders in this
respect, coupled with their contemporaneous and early appearance,
suggests that they originated independently. Whether they sprang
from a common stock or are fundamentally distinct, is a problem
which cannot be attacked on these lines of argument.

5. Tuer Cassrpunor PERISToME.

I have examined the interior of the peristomial region in Conulopsis
(Eechinoconus, Desor) only among the many representatives of this
Order. The evidence thus obtained, though interesting and
suggestive, cannot therefore be considered adequate for the formula-
tion of any definite hypothesis. It seems, however, sufficient to
indicate the phyletic distinction between this Order and the
Nucleolitoida, with which it is generally associated.

Externally, the adoral region in this Order is characterized by the
expansion of the proximal parts of the ambulacra into variously
developed phyllodes, separated from one another by more or less
prominent ‘‘bourrelets”’ on the interambulacra. (Many of the more
elaborate Nucleolitoida, such as Clypeus and Pygurus, are similar in
this respect.) Internally, the thickening of the interambulacra is
almost like a reflection of their external character, so that the
interradial margins of the peristome are excessively massive.

In Conulopsis abbreviata, from the Upper Chalk of Norfolk,
the phyllodes are practically non-existent, although pronounced
‘‘bourrelets’’ are developed. An internal view of the adoral surface
shows a remarkable resemblance to that seen in Conulus, and is of
itself enough to render the generic name morphologically appropriate,
whatever may be its systematic fate. ‘he ambulacra are terminated
adorally by an almost unthickened edge, and so appear as five grooves
radiating from the slightly elliptical aperture of the peristome. ‘The
interambulacra increase steadily in thickness from the ambitus almost

w

iE Herbert L. Hawkins—Studies on the Echinoidea.

to their proximal termination, and are then steeply bevelled off by
a pair of concave bays or ‘‘combes’’, between which the areas project
as rounded spurs almost overhanging the slope of the ‘‘ escarpment ”’.
The two “‘combes” in each area are most deeply excavated just on
the interradiad side of the adradial sutures. Here they appear as
deep slots, differing only in proportion from the hollows in the false
ridges of Conulus. By analogy, it would seem that these hollows in
the peristomial margin of Conulopsis must have been destined to
receive massive buccal plates when the mouth was opened.

Unless Conulopsis is on a side line of evolution, it would appear to
be a simple member of the Caratomide, and as such more or less
ancestrally related to the ZEehinolampas-group. Whatever be its
other affinities, it must surely be nearly related to Conulus, to judge
from the nature of most of its test-structures. As far as the
perignathic girdle is concerned, it may be considered to show the
retention of the false ridges of Conulus, after the loss of both sets of
the ‘‘true”’ elements of the girdle. From the scanty evidence at my
disposal, I believe that Catopygus, a far more ‘‘ advanced” type of
Cassiduloid, has a similar perignathic structure. Clarke & Twitchell
(The Mesozoic and Cenozoic Echinodermata of the United States) give
figures of internal moulds of Cassidulus californicus (pl. xv) and
Pygorhynchus gould (pl. lxxix) which show a strong interradial
thickening of the interior of the test at the peristome in these
typically Cassiduloid species.

6. Tue Sparancorp PEristomMeE.

For the present purposes I have examined the interior of the test
in many examples of Hehinocorys, Micraster, and Echinocardium.

The predominant feature of the peristome of the Spatangoida is its
progressive adaptation to the requirements of a burrowing life and
an ‘‘earthworm”’ mode of feeding. The part of the aperture
bounded by interambulacrum 5 comes to project below the general
level of the adoral surface, and its margin develops into a spoon-like
labrum. All Spatangoids, as far as is known, are entirely destitute
of jaws. MacBride has recognized as teeth certain spicules produced
at a very early stage of post-larval ontogeny, but no pyramid or
auricular vestiges seem to be associated with them, and they disappear
shortly after their formation.

Klinghardt has identified as ‘“‘auricles’”’ certain protuberances at
the side of the peristome in Lehinocorys, but the examination of
considerable numbers of specimens of #. vulgaris, representative
of many of the later growth stages, has convinced me that these
blunt excrescences are not processes (being based upon the inter-
ambulacra), so that they can hardly be homologous with any part of
a perignathic girdle in the strict sense of the term.

Reference has been made in the preceding article of this series to
the curious ‘‘mode” of excessive stereom-formation prevalent among
the Kchinoids of the Cretaceous period. The early Spatangoids
almost universally adopted this character, so that the margins of
their peristomes are always of considerable thickness. This applies

Herbert L. Hawkins—Studies on the Echinoidea. 13

particularly to the anterior and posterior edges of the aperture.
The thickness is always greater in the interambulacral parts than in
the ambulacral. Save on the edge of the labrum, there is no
indication that the thickened margin is adapted to any special
requirement beyond that of strengthening the free edge of the
corona. In the case of area 5, the lip is often rolled over away from
the peristome, and overhangs the ‘‘bowl”’ of the spoon-like labrum
to a slight extent. In the (presumably) more primitive types, where
the labrum is hardly worthy of the name (e.g. Hehinocorys) there is
no trace of such a specialization of the margin, which is merely
thickened similarly to, but in a less degree than, the other inter-
ambulacral edges; it must consequently be a secondary development
suited to the needs of a labrum, and can have no homology with the
perignathic ridges of less specialized groups. On the thickened
margins of areas 2 and 8, in Hehinocorys and Mieraster, the line of
attachment of the buccal membrane is often apparent. Within this
the secondarily thickened margins rise almost vertically, and seem to
show no feature inconsistent with the belief that they are simply the
truncated edges of the coronal plates. They certainly constitute
“false ridges”, but whether they are to be correlated with those of
the Holectypoida is very doubtful.

In most of the Recent Heart-Urchins there is a more or less
extensive alar projection from interambulacrum 4 near the margin of
the peristome. In many forms a corresponding, but only just visible,
projection occurs in area 1, These projections afford support for
the mesenteries holding the proximal parts of the alimentary canal.
They have been regarded by some authors as modifications of parts of
a perignathic girdle. The only fossil in which I have succeeded in
recognizing even a trace of such a projection is a Schizaster from
the ? Miocene of Hast Africa. The extreme delicacy of the free part
of the structure is such that only its foundations could be hoped for
under the conditions of fossilization. It is possible that the pre-
sumed ‘‘ auricles’? described by Klinghardt in ehinocorys may
represent such a structure, though they seem to be somewhat sporadic
and irregular in their occurrence. But I have never seen a trace of
these projections in any Cretaceous Spatangoid. As far as my
experience goes, these cesophageal supports are a recent development
restricted to fully specialized Heart-Urchins, and so are not likely
to be homologous with any part of a true perignathic girdle.

As at present known the peristomial characters of the Spatangoida
give no satisfactory clue to their morphogenetic relationships, while
their more elaborate features are purely secondary developments,
quite unconnected with any ancestral qualities.

7. SUMMARY.

The perignathic girdle of the Holectypoida is believed to consist
of disjunct processes situated almost on the adradial sutures, with
minute ‘‘ true ridges’’ occupying the inner surfaces of the unpaired
interambulacral plates. This character is constant throughout the
group, although it may be partly obscured by the development of

14 Herbert L. Hawiins- “Studies on the Hohinordeae

‘‘false ridges”? due to requirements of mechanical strength and to
the phenomenon of “super-calcification”’. The girdle, apart from
such modifications, is shown to be essentially primitive—more so
than that of any modern Diademoids.

By the default of the proximal interambulacrals, or by an actual
transgression of the processes, the ridges are wanting in the
Clypeastroida, and the processes converge towards the interradial
line, often fusing in pairs. Such a character may readily have been
derived from the Holectypoid girdle. The presence of so great
a complexity of internal buttresses in the Clypeastroida points to
their derivation from some Cretaceous representative of the
Holectypoida, in which series alone such structures are strongly
developed.

The Wucleolites series of Jurassic so-called Cassiduloida (here
styled Nucleolitoida) seem to possess no trace of a perignathic girdle,
even in the simpler and early forms. ‘The sudden disappearance of
the apparatus (there can be hardly any doubt that the ancestors
of all Euechinoida were gnathostomatous) seems to point to the
conclusion that the Nucleolitoida arose independently of, but con-
temporaneously with, the Holectypoida.

The Cassiduloida, to judge from the characters of one of the least
specialized forms, Conulopsis (and, I believe, from those imperfectly
known in Cassidulus itself), have a much thickened peristome in
which there is a strong resemblance to that of Conulus, although the
actual ossicles of the girdle are wanting. It is suggested that the
false ridges are retained in this group, which becomes thereby
affiliated to the Conulus series of the Holectypoida.

The Cretaceous Spatangoida have much thickening of the
peristomial plates, especially in the anterior region, but it has not
been possible to correlate any of their structures with the girdle,
true or false, of the Holectvpoida. The cesophageal support
developed on one or both sides of the peristome in the later Heart-
Urchins is regarded as an entirely secondary structure, with no
affinity to any portion of a perignathic girdle.

EXPLANATION OF PLATE ILI.

Fie. 1.—Interior of peristome of Conulopsis abbreviata. xX 6. The floor of
the test is thickened in the same manner as that of Conulus, and deep

_ slots (? for the reception of retracted buccal plates) are cut in the
peristomial ‘* escarpment ’’. The actual aperture is very slightly elliptical.

», 2.—Interior of peristome of Hchinocorys vulgaris. x 5. Except in
area 5 the floor of the test increases in thickness towards the peristome.
In the four lateral interambulacra single, crescentic hollows excavate the
“escarpment’’. The horns of the crescents in areas 2 and 3 are often
nodular, being the “‘ auricles ’’ noted by Klinghardt.

,, %.—Plan of interior of peristome in Hchinocardiwm cordatum. In area 1
there is a small knob which rises partly from the neighbouring ambulacral
plates. In area 4 a long, twisted mesentery-support rises from foundations
exactly similar to those in area 1. The edge of the labrum is slightly
reverted. There is no special modification in areas 2 and 3.

Grou. Mac., 1918. PrarE Il,

H.L.H. del.

INTERIOR OF PERISTOME IN CONULOPSIS, ECHINOCORYS AND
ECHINOCARDIUM.

ihe
es

x - X ‘hi \ j

Alfred Bell—Age of the Suffolk Boxstones. 15

T11.—Tue Surrotxk Boxstonrs AND THEIR PROBABLE AGE.
By ALFRED BELL.
(PLATES III AND TV.)

fJ\HE detrital matter underlying the Suffolk and N.W. Essex

Crags forms an incongruous mass of disrupted local rocks and
fossils, supplemented by a few transported boulders of igneous and
sedimentary rocks of different ages and mostly small. To these have
to be added organic remains of many classes in various conditions of
preservation.

The bulk of this miscellaneous assortment consists of clays and
sands metamorphosed by phosphatization and other agencies, whose
fossils indicate two or more distinct horizons ; to place these in their
proper geological positions it is requisite to see what relations they
bear to those of the deposits, or strata, above and below, and to
consider the causes that brought them into their present position.

The area occupied by this detritus is exceedingly limited, not more
than sixty square miles in extent, the remains of a much larger
surface, now lost or destroyed by marine action wearing away the
coastline. Red Crag, with flints and phosphates, occurs a few miles
inland as far as Sudbury and Monks Eleigh.

The fossils belong to two series, the older one rich in fishes and
crustaceans, usually embedded in a highly phosphatized clay, the
so-called ‘‘ Coprolites’’. Amongst the fishes, the genera Cymbcum
and Ha/lecopsis, with the bodies hardly compressed or altered in
shape, are very common; the pavement-toothed Phyllodus and
Pycnodus were frequently obtained when the pits were being worked.
The crustacea have yielded eighteen or twenty species, including
one Nephrops Reedii, Carter, which has not been recognized elsewhere
in the London district. These indicate a zone corresponding
generally to that of the London Clay of Sheppey in Kent. Both
fishes and crustaceans are often in fine preservation, unlike the
shells, which seem to have been absorbed or converted into phosphate
pseudomorphs, and are not pyritized as they are in the Sheppey area.

Casts of a few of the aragonite mollusca are preserved as a sandy
or clayey matrix, but slightly phosphatized, the shelly material
having entirely disappeared. It is difficult in these cases to
determine to which horizon they belong, as the genera Cytherea,
Pectunculus, etc., are common to both Eocene and Oligocene, the
more so as several species, including Cancellara (Bonellitia) evulsa,
a few Volutes, and Pleurotoma, Rimella and Hippochrenes, pass
upwards. Professor Prestwich,’ moreover, says: ‘‘The Argile de
Boom” (to which I shall presently refer) ‘‘ attains around Antwerp
a thickness of 200 feet, resembling very closely, in its general
composition and the facies of its fauna, the London Clay, to which
it was originally referred.” }

The fauna of these older Eocene clays in England and that of the
next group tu be considered have very little in common, the
teleostean fishes and others just mentioned having passed away.

1 Geology, vol. ii, p. 382, 1888.

16 Alfred Bell—Age of the Suffolk Boxstones.

After eliminating the Eocene faunas referred to, there remains
a miscellaneous series of both marine and terrestrial organisms, the
former being mostly contained in the boxstones and sandstones, of
which they form a part (see Gror. Mac., September, 1917, p. 408).

Professor Boswell, F.G.S., has carefully examined and described
the petrology of the boxstones, and suggests that some of them may
have been formed by concretionary segregation of iron oxides, calcium
phosphate and carbonate around organic nuclei.’ As a rule they are
irregular in shape, often water-worn, sometimes nearly spherical,
and of many degrees of hardness, according to the amount of iron
in their composition; the sand at times being apparently full of small
tubes (? annelids), loosely cemented, and light in weight and colour.
‘The excessively hard masses are usually devoid of organic remains of
any kind. It is impossible to separate these indurated boxstones,
spherical or otherwise, from the tabular sandstones and loose shells
found in the body of the Crag, presently to be referred to, as the
same species of shells occur also in them. These amorphous lumps
can hardly be termed nodules in the sense usually understood. In
these as in Cromarty, like the Ichthyolite beds of the Old Red
Sandstones, in the White Lias, in the Pennystone nodules of the
Coal-measures with their exquisitely preserved Crustaceans and
other invertebrata, or those of Coalbrookdale enclosing delicate fern
fronds and pinnules, the nodules follow the lines of that of the
organisms enclosed. ‘The cement stones of the Essex London Clay
at Harwich containing Chelonians may also be regarded as larger
examples of the same kind.

On the other hand, the fossils of the boxstones often occur at an
irregular angle, according to the way in which the sandstone may
have broken up. Several individuals are frequently present in the
same block.

The Mekran nodules described by Mr. R. B. Newton,” fairly
represent the usual method of inhumation in the best-preserved
boxstones, so that the same words must apply to both. “ The condition
of the fossils is nearly always that of a natural cast exhibiting
internal structure, whilst external features are often preserved in the
concavity of the shell.” ;

‘he exterior of these Mekran nodules, ‘‘ many as round as a ball
with perfectly even surfaces,” has but a superficial analogy to that
of the boxstones in general.

Dr. J. J. H. (now Sir Jethro) Teall, F.R.S., in his presidential
address to the Geologists’ Association® dealing with ‘The Natural
History of Phosphatic Deposits”, describes the boxstones (p. 383) as
‘‘nodules of brown phosphatic sandstone which usually contain
hollow moulds of Pectunculus or other (calcareous) shells”’, and quotes
Dr. H. Credner, who in treating of the phosphate nodules of the Middle
Oligocenes of Leipzig where similar nodules occur in place, says,
‘the phosphate, mainly phosphate of lime, has been concentrated

1 Grou. MaG., Dec. VI, Vol. ii, p. 250, 1915.

2 R. B. Newton, F.G.S., ‘‘ Marine Fossils in Limestone Nodules found on
the Mekran (Baluchistan) Beach ’’: GEOL. MaG., Dec. V, Vol. ii, 1905.

3 Proce. Geol. Assoc., vol. xvi, p. 369, 1899-1900.

Alfred Bell —Age of the Suffolk Boxstones. 17

round calcareous shells and fish remains, but the shells have entirely
disappeared, and the fish are represented only by the more insoluble
portions of their skeleton.” Carbonic acid and ammonia are
formed in connection with the decomposition of animal matter.”
<¢ Phosphate of lime is soluble in water, charged with carbonic acid,
and still more so in water containing ammonium carbonate. A solution
of ammonium phosphate is thus formed at the expense of the fish
bones, and one of calcium carbonate at the expense of the shells.
The shells and the fish embedded in the porous sand thus become
surrounded by water highly charged with calcium carbonate, or
ammonium phosphate. Where these solutions react there is a
precipitation of calcium phosphate and some carbonate; in this way
the loose sand becomes consolidated into a hard nodule.” Dr. W. B.
Clarke! was the first to give any detailed account of the detritus bed.
He especially refers to the boxstones as ‘‘ arenaceous clay nodules
that have been rounded by attrition into forms, more or less spherical,
upon breaking which a shell, frequently a bivalve, is found in the
interior. In some cases the shell itself is preserved, in others
nothing but the cast remains”. He seems to have anticipated
Dr. Credner by saying, ‘‘It is not unlikely that the presence of the
shell and its molluscous inhabitant, involving certain chemical
changes within the mass of clay, may have given rise to the
consolidation of the surrounding mass.”

Many phosphatic concretions were dredged by the Challenger off
the Cape of Good Hope and elsewhere, where sharks’ teeth abounded,
as many as 1,500 examples of these being taken in one haul of the
dredge. Sharks’ teeth abound in the loose sand of the older Red
Crag; nearly all the species are recorded from the Continental
Oligocene, while a few survive to the present time.

In working out the relations of the boxstone fauna to that of other
formations I have utilized the lists given by Dr. Harder,’ Dr. Ravn,*
M. Vanden Broeck,4 Dr. Nerregaard,® and by Mr. R. B. Newton,
F.G.S.6 In making these comparisons I have left out the loose
derivative shells found in the Red Crags, but these are all referred to
by one or other Continental writers as being of Oligocene age, and
do not affect the conclusions at which I have arrived.

Harder quotes 93 species from the Oligocene zones ; 21 of these are
boxstone species, chiefly Middle Oligocene (23 per cent approx.).

Ravn 91 species, Middle and Upper Oligocene, of which we have
36—40 (44 per cent).

Vanden Broeck 64 species, Middle Oligocene; Argile de Boom
(Upper Rupélien) 22-24 (38 per cent); Lower Rupélien (Berg)
62 species, of these I have only found 10 in the boxstones.

a

““\ few remarks upon the Crag of Suffolk’? : Ann. Mag. Nat. Hist. (2),
viii, p. 205.

Danmarks geologiske Undersegelse, vol. ii, 1913.

K. Danske Vid. Selsk. Skrift (7), vol. iii, p. 217, 1907.

Bull. Soc. Belge de Géologie, vol. vii, p. 78, 1893.

Dansk. Geol. Forening., vol. v, No. 1, 1916.

Journal of Conchology, vol. xv, 1916-17.

DECADE VI.—VOL. V.—NO. I. 2

—

yol.

nonirp c WD

18 Alfred Bell—Age of the Suffolk Boxstones.

Dr. Norregaard’s list of 64 species, as noted further on, yields
16, or 25 per cent, boxstone forms. Mr. Newton’s list of 77 species,
10 or 11, or about 13 per cent.

Ravn’s list, when closely examined, gives 51 Middle Oligocene
species, including 15 boxstone forms or about 30 percent, as compared
with Vanden Broeck’s 38 per cent.

These analyses show that the ‘‘ boxstone’’ sands are nearer to
the Oligocene Argile de Boom than to any of the others; they may
be classed, I suggest, as Upper Rupélien.

‘De Koninck, in his classic memoir on the fossil shells of Basele,
Boom, etce., has figured or described many of the shells since found in
the boxstenes; the above view is strengthened by the presence, both
here and in Belgium, of similar types of vertebrates, many Elasmo-
branch fishes and Crustaceans, various species of fossil woods, and
vegetable debris.’

Dr. Clarke noticed the abundance of long thin rolled plaquettes of
waterworn bones, which caused Sir KE. Ray Lankester to call the
deposit in which they occur ‘‘the Suffolk bone-bed”. They are
seldom, if ever, coated with the sandstone matrix, and it is very
probable that they did not become mineralized till a later period, as
the bony fragments enclosed in the nodules do not show any signs of
such action.

Phosphatization is not confined to age or place, as Sir Jethro Teall *
has pointed out. Professor Herdman® says also of certain oysters:
‘‘The shells were worn, many were brown in colour and polished,
indicating a partial conversion into a phosphatic condition.”

The presence of fossiliferous boulders in the north-west continental
area bordering the North Sea is well known. Herr Norregaard *
states he has collected these blocs from a tudlerve near Esbjerg, and
although he classes them as Middle Miocene notes that “their fauna
differs considerably, in certain respects, from that of the Danish
Miocene”’ (op. cit., p. 46). His list of fossils from these boulders
runs into sixty-four species. Sixteen of these, including Cardiwm
ceingulatum, Turritella Geinitzt, Aporrhais speciosa, and Pleurotoma
Stemmvorthi, are included in our boxstone fauna.

Mr. Harmer informs me that Mr. van Waterschoot van der Gracht,
the Director of the Geological Survey of Holland, told him that
blocks of fossiliferous limestone, believed to be of Oligocene age,
were not infrequently dredged by the North Sea fishermen.

The ‘ fossiliferous limestone block from the North Sea” ®, described
by Mr. R. B. Newton, F.G.S8., seems to have had a similar history.
It ‘‘has not suffered a sea change’’, nor does it show any signs of
abrasion or water-action. The stone is, I suggest, older than
Mr. Newton makes it, and has been, I think, but recently cleared of
the enveloping clay. Iam sorry to disagree with his interpretation

1 Mem. Acad. Roy. Bruxelles, vol. xi, 1837.

2 Proc. Geol. Assoc., vol. xvi, p. 385.

3 Report on Ceylonese Pearl Fisheries, Roy. Soc., 1903, p. 348.

4 **Mellem Miocene Blookke fra Esbjerg’’: Dansk. Geol. Foren., vol. v,
No. 1, 1916.

Q.J.G.S., vol. Ixxii, 1917.

Alfred Bell—A ge of the Suffolk Boxstones. 19

of certain forms, but in place of Ranella gigantea, Aporrhais pes-
pelicamt, and Yoldia oblongordes, for example, I am inclined to read
Triton flandricum, Aporrhais speciosus, and Yoldia glaberrima, all
well-known Oligocene or Miocene species. The Watica figured as
NV. Alderi isnot the recent form found in British seas; it may possibly
be a variety of WV. Wystiz, like the one figured by Harder (op. cit.,
pl. v, fig. 27).

Another question arises in connexion with the ‘‘ boxstones”’,
1.e. how did the terrestrial mammalia and extra-local rocks become
associated with them, the vertebrates being of Miocene and Pliocene
ages, a connecting link appearing in the Mastodon tooth, described
by Sir E. Ray Lankester as having the valleys or hollows between
the cusps filled with the boxstone matrix.

The latter writer described the detritus bed as a great beach or
littoral accumulation formed immediately before the Coralline Crag
and derived from many sources. I venture to suggest a different
solution, viz. that the older phosphatized clays were originally
deposited as the upper portion of the London Clay, as testified by its
fossils, the boxstone sands being afterwards laid down upon this,
both clays and sands having been but little removed from their
original situation.

The sands were probabiy deposited in the coralline zone at
a moderate depth, the presence of so many double bivalves with
valves closed, and the almost total absence of any of the littoral or
shore-haunting molluscs, being a conspicuous feature. In due time
this edge of the Anglo-Belgian basin became raised above the sea-
level, and remained during that period of elevation as an upraised
plain on whose surface the animal remains referred to were
accumulated in local fluviatile deposits from time to time.

Both clays and sands seem to have been desiccated and dis-
integrated before the time of the Coralline Crag, but not disturbed,
as we find it in position beneath the borders of this deposit at
Sutton and Boyton. Beyond this it disappears, no traces of it
having been found by Mr. F. W. Harmer when boring into the Crag
outside these places.

The detritus did not pass up into the body of the Coralline Crag,
but in the succeeding zones, the Oakleyan and Newbournian stages,
the Red Clay is full of the broken-up debris,’ and flints became
abundant either as isolated blocks of large size and unabraded, with
the cortex beautifully preserved or as waterworn pieces of smaller size.

Under the submarine currents of the Coralline Crag sea the floor
was but little disturbed, but at the close of its earliest portion,
the Gedgravian of Harmer, a change in the fauna commenced, and the
Boytonian period ushered in sundry tectonic changes, several species
of northern or boreal mollusea, such as the Belas, making their
appearance for the first time in East Anglia. This zone or period
passed away, and with it a part of the older southern fauna, to be
replaced by a more northern one. The flints just mentioned were
due, according to Sir C. Lyell, to ice-action. Many of the smaller

1 See Bell, ‘‘Sub-Crag Detritus’’: Proc. Prehistoric Soc. East Anglia,
1915, vol. ii, not vol. xi as on p. 408 (ante).

20 = Alfred Bell—Age of the Suffolk Bowstones,

pieces occur in patches, on strings in slight depression of the soil
beneath, as if an ice-floe, loaded with thes se stones, had grounded,
leaving its burden intact. One such flint patch is present between
the Coraline and Red Crag at Pettistree Hall, Sutton, on the
Coralline Crag Hill of Pr estwich," where I saw it in situ.

In the Newbournian period of the Red Crag, stormy seas seem to
have been the normal feature, churning up the disintegrated sea-floor
with its contents so as to make the fraements an integral part of the
deposit it was then building.

The fossils selected in illustration of this paper have been chosen
as specimens of the various ways in which they occur, or as being
_ unfigured species. The nomenclature I have used in this and the
earlier paper will not perhaps commend itself to some scientific
experts, but may be the better understood by ordinary workers in the
Crag as being the language they are more familiar with, and will
enable them to refer to earlier writers with greater facility. These
continual changes in nomenclature are very bewildering to
students in general.

A further revision of material, lately come to hand, enables me
to add a few species to those already quoted in No, 639 of the
GrotocicaL Macazinn, September, 1917. :
2Liomesus Feldhausit (Beyrich), Zeitsch. deutsch. geol. Ges., vol. viii,

p. 243, pl. i, fig. 9, 1856. Mus. Pract. Geol. London.

[Except that the boxstone shell is larger than the type there seems to be no
difference, either in form or sculpture. ]

Pseudocassis Harmert, n.sp. (see p. 413 ante for reference). Harmer Coll.
Solariwm Hornesii, Michelotti, Htud. Mioc. inf. Ital., p. 92, pl. x, figs. 11-12,
1861. Mus. Ipswich.

[Iwo examples, both showing the underside, may be referred to this species.
Moulds of the wall of the umbilical opening may be easily mistaken for the
upper whorls of a small Cancellaria. |
Cardium fragile, Brocchi, Conch. foss. subap., vol. ii, p. 505, pl. xiii, fig. 4,

1814. Mus. Pract. Geol. London.
Mactra ovalis, J. Sowerby, Min. Conch., vol. ii, p. 136, pl. elx, figs. 2-5.
Mus. Pract. Geol. London.

[The two last-named occur with Pecten Rwupéliensis, Pectunculus, and
a number of others—mostly imperfectly exposed bivalves—in an irregular plaque
of sandstone, see ante, p. 408. |

EXPLANATION OF PLATES III AND IV.

PLATE III.
FIG.

a

Fasciolaria erratica (De Koninck), p. 411. la shows details of sculpture,
16 the internal mould. Mus. Ipswich.

Sipho Ravni, u.sp., p. 411. Mus. Ipswich.

? Liomesus Feldhausii (Beyrich). Mus. Pract. Geol. London.

Ficula acclinis (S. V. Wood), p. 412. Mus. Ipswich.

Cominella conica, n.sp., p. 412. Mus. Ipswich.

Semicassis saburon (Bruguiére), p. 412. British Mus.

Pseudocassis Harmert, n.sp., p. 413. Pseudomorph in a phosphatized
matrix. Harmer Coll.

Trigonostoma cf. ampullacea (Brocchi). Mus. York.

Solarium Hornesvi, Michelotti. Mus. Ipswich.

1 Q.J.G.S., vol. xxvii, 1870.

co CO WA OP oo bo

Guop. Mac., 1918. shed Prate TH.

G, M Woodward del, Bale, imp.

CASTS OF SHELLS FROM THE SUFFOLK ‘BOX STONES.”

Aen ane eer

}
‘

Gror. Maa., 1918. i > Presi

Bale, imp.

G. M. Woodward del.

CASTS OF SHELLS FROM THE SUFFOLK ‘BOX STONES.”

RE TOsens he Shand—The Norite of the Sierra Leone. 21

PLATE IV.

Fie. 6

10. Voluta (Pyrgomitra) fusus (Philippi), p. 410. Mus. Ipswich.

11. Conus antediluvianus, var.,Grateloup, p.410. Mus. Pract.Geol. London.

12. Plewrotoma Steinvorthi, Semper, p. 410. Mus. York. .

13. Natica ferruginea, var. (in Sacco), p. 414. Mus. Ipswich.

14. Calliostoma Xavieri (Costa MS.), p. 415. Mus. Ipswich.

15. Nucula placentina, Lamarck. Mus. Ipswich.

16. Astarte Kickxti, Nyst., p. 417. Mus. Pract. Geol. London.

17. Cardium Woolnoughi, n.sp. 17a shows the sculpture as seen in the
intaglio or hollow mould. 170, inner mould of organism with the shell
removed by decalcification. Mus. Pract. Geol. London.

18. Cyrtodaria vagina (S. V. Wood). Mus. Pract. Geol. London.

19. Flabellui cuneatum (Goldfuss). Bell Coll.

Ve: Lia Norire oF tHn Srerra LrEone.
By Professor 8S. J. SHAND, D.Sc., F.G.S., University of Stellenbosch, Sonth
Africa.

NHE Sierra Leone, from which the Colony of Sierra Leone takes
its name, is a range of palm-covered hills running parallel to
the coast (N.N.W.-S.8.E.). It is truncated on the north by the
wide mouth of the Roquelle (Rokell) River, which forms the
magnificent harbour of Freetown. Towards the south the range
terminates at Yawry Bay. The length of the Sierra is therefore
about 25 miles and its width, from Kassa Town to Kissy,
about 8 miles. On the east side the range descends steeply to the
Kwaia plain, from which it is separated by Waterloo Creek. The
detachment of the hills from the interior lowland is sufficiently
complete to entitle one to speak of the Sierra Leone Peninsula.
Freetown is built on the north end of the peninsula, overlooking the
harbour, and it straggles up from sea-level to a height of some
800 feet on Wilberforce Hill. The greater part of the peninsula is
covered with thick tropical vegetation right down to sea-level; and
an additional obstacle to geological study is created by the heavy
covering of laterite which screens the rocks from observation. In
places this laterite mantle is 30 feet thick. But along the northern
shore of the peninsula, from Cape Sierra Leone to the mouth of
Waterloo Creek, there are nearly continuous exposures of norite,
and further useful exposures have been made during the construction
of the Hill Railway and along certain of the roads on the hillside.
These outcrops make it clear that the whole of the north end of the
Sierra is formed of norite, and it would not be surprising to learn

that the entire Sierra has the same composition.

The norite or gabbro of Freetown was described by G. Giirich in
1887,1 and I have not been able to trace any subsequent reference to
it. Rocks from the interior of the colony were examined by G. F.
Scott Elliot and Miss C. A. Raisin in 18938,?and as far as I am aware
no further contribution to the geology or petrology of the country
has been made since that date. I spent a few days in Freetown
recently, and took advantage of the opportunity to examine the rocks
and collect a few specimens. I can add little to the account of the

' Zeit. der Deutschen Geologischen Gesellschaft, vol. xxxix, p. 108.
2 Colonial Reports, Misc., No. 3 (Sierra Leone), p. 61.

22 Prof. S. J. Shand—The Norite of the Sierra Leone.

norite given by Giirich, but where the whole store of observations is
so meagre any addition to it ought to be useful. It is desirable in
any case that records relating to British colonies should be accessible
in the English language.

The rock, as exposed about Freetown and on Wilberforce Hill,
shows the following textural facies.

1. A coarse-grained variety, sometimes forming definite pegmatite
veins, composed mainly of felspar plates in sub-parallel arrangement.
Some of the crystals are nearly an inch in diameter, and their colour
is iron-grey. ‘he coarser the grain of the rock, the smaller the
proportion of heavy minerals, which may sink to 5 per cent or less.

2. A medium-grained variety which may be called the average
rock, in which the felspar crystals have diameters of 2 to 4 mm.
The arrangement of the crystals is still sub-parallel. Olivine grains ~
are prominent, and the heavy (or mafic) minerals constitute about
25 per cent of the volume of the rock.

3. A fine-grained variety in which the crystals are equidimensional
and have an average diameter of less than 0°6mm. ‘The texture is
similar to that of an aplite, or what is sometimes called a “ trap-
granulite’’. Heavy minerals make up some 60 per cent of the whole.
I believe this facies of the rock to bear the same relation to the last
that an aplite bears to a granite.

The following minerals are present: plagioclase, olivine, hyper-
sthene, diallage, titanomagnetite.

The plagioclase is entirely fresh and glassy, and invariably dark-
grey in colour. In general it forms pinacoidal tables with Carlsbad
and albite twinning, but in the aplitic rock it appears in anhedral
grains. ‘The extinction angles show it to be an acid labradorite,
approaching Ab, An,. No zonal structure could be detected.

Olivine is an important constituent of the average rock, but is
entirely absent from the aplitic facies. It is perfectly fresh, or
shows only incipient hydration along cracks. The crystals are
moulded upon the felspars, and are sometimes mere skeletons
embracing numerous felspar laths. Gtrich has illustrated this
feature in his paper. Olivine iscommonly intergrown with diallage
and may be enclosed by hypersthene. Some varieties of the rock
contain little but felspar and olivine.

Diallage of asmoky-brown colour is the common pyroxene in the
coarser varieties of the rock. It is charged with opaque ore-
inclusions which le along planes of parting. It forms skeleton-
crystals surrounding felspars, and rounded grains of diallage are
often completely enclosed in hypersthene.

Hypersthene is the only ferromagnesian mineral present in the
aplitic facies of the rock, but in the average rock it is associated
with, and generally subordinate to, diallage. In the former case the
hypersthene grains are equidimensional, and they form an even-
grained aggregate with anhedral felspar grains of the same size.
Even here, however, the hypersthene has demonstrably been moulded
on the felspar. In the coarser varieties of the norite the hypersthene
occurs in anhedral plates which enclose all the other minerals of the
rock. The pleochroism is strong, indicating a high iron-content.

Notices of Memoirs—Geology of the Forest of Dean. 23

Magnetite (titanomagnetite) is present in irregular, often rounded
grains, but some crystals show isometric sections. A highly refracting
border (leucoxene ?) surrounds some of the grains, indicating the
presence of titanium. Scott Elliot noted the occurrence cin the
hills behind Sierra Leone” of a titaniferous iron-ore yielding 52 per
cent of metallic iron and 14 per cent of Ti Op. Giirich, too, saw in
a private collection of minerals in Freetown lumps of magnetite
as large as the fist. I venture to conclude that this ore-body occurs
as a segregation within the norite; indeed, the recognition of the
petrographic character of the rock would lead one to anticipate the
existence of such segregations. These indications ought to be
followed up, as they might lead to the discovery of important ore-
deposits. The matter is one for the attention of the Imperial
Mineral Resources Bureau.

Estimates of the percentage composition of these rocks yielded the
following results in the case of (A), a specimen of what I have called
the average rock, and (B) the aplitic facies :—

A. B.
Vol. %. Weight-%. Vol: %: Weight %.:
Plagioclase . : 74 69 41 35
Olivine . : F 14 16 0 0
Diallage | 9 10 f 0 0
HyperstheneJ = \55 59
Magnetite . é 2°3 4 4 6

The order in which the minerals crystallized is as follows:
labradorite, olivine, diallage, hypersthene; magnetite uncertain. In
brief, the fine-grained rock is a melanocratic norite (mg — micro-
norite), while the coarser varieties are leucocratic olivine-norites
(1, —toly- subnorite). I invite attention here to a change which
ought to be made in the subdivision of the gabbroitic rocks ; namely,
that in deciding whether a rock is to be attached to gabbro or to
norite the olivine should be reckoned along with the rhombic pyroxenes,
since the latter minerals arise by the addition of silica to olivine.
Thus all troctolites and ‘‘olivine-gabbros’’ (including those above
described) in which the sum of olivine plus rhombic pyroxenes
exceeds that of the monoclinic pyroxenes should be regarded as
norite (subnorite), no a as Gabon:

NOTICHS OF MEMOTRS.-

On tHE GrotocicaL SrrucruRE oF THE Forest oF Drawn.’ By
T. Franxuryn Srsry, D.Sc., F.G.S8., Professor of Geology in the
University College of South Wales and Monmouthshire, Cardiff.
(A paper read before the Forest of Dean Branch of the National
Association of Colliery Managers on October 25, 1917.)

a 1894 Dr. R. Kidston correlated the Coal Measures of the Forest
of Dean with the true Upper Coal Measures.* In 1910 Dr. T. T.

Groom, reasoning from this correlation, pointed out that ‘‘ unless the

1 Reprinted (by permission), with some emendations by the author, from

the Colliery Guardian, vol. exiy, No. 2966, November 2, 1917, pp. 839-40.
2 Proc. Roy. Phys. Soc. Edin., vol. xii, p. 222, 1894.

24 Notices of Memoirs—Professor T. Franklin Sibly—

measures that have not been detected [the true Lower and Middle
Coal Measures] are exceedingly thin, or are represented by the
upper part of the Millstone Grit, there must be an unconformity at
the base of the Coal Measures’”’.' \

The late Dr. A. Vaughan had proved the Lower Carboniferous age
of the lowest beds of the Millstone Grit near Mitcheldean.* In 1912
Dr. E. A. Newell Arber, whose detailed study of the fossil plants in
the local Coal Measures confirmed Dr. Kidston’s correlation, wrote as
follows: ‘“‘ Reviewing the present evidence I am inclined to think
that it will eventually prove that an unconformity exists a short
distance below the Lower Trenchard Coal perhaps a little above the
Sandstone vein of Iron Ore. ... True Millstone Grits, Lower,
Middle, and Transition Coal Measures appear to be absent in the
Forest of Dean, so that the unconformity in question is of consider-
able importance.’’ ®

The present author’s independent investigations led him in 1912
to the conclusion that an unconformity at the base of the Coal
Measures is an important structural feature in the Forest of Dean.
In a short paper on the Carboniferous succession* he described the
Lower Carboniferous sequence near Mitcheldean, proposed the name
Drybrook Sandstone for the ‘‘ Millstone Grit” of the district, and
demonstrated the reality of the intra-Carboniferous unconformity by
describing the persistent overstep of the Coal Measures across the
Drybrook Sandstone and Carboniferous Limestone, as well as by
other evidence.

The author has been assisted in his later researches in the
district by a grant from the Government Grant Committee of the
Royal Society. He is permitted by the Director of the Geological
Survey of Great Britain to make use of information gained in the
course of his present investigation, as an officer of the Geological
Survey, of iron-ores in the Forest of Dean.

It is well established on paleontological evidence that the
Carboniferous Limestone of the Forest of Dean represents, approxi-
mately, the lower half only of the same formation as seen in the
Avon Gorge at Bristol. The zones of the Carboniferous Limestone
Series in the Avon Gorge, recognized by the late Dr. Vaughan, are
denoted, in ascending sequence, by the symbols K, Z, C, 8, D.
The highest member of the Carboniferous Limestone on the north-
eastern borders of the Forest of Dean, the Whitehead Limestone,
represents the topmost part of C (Syringothyris zone) and possibly
the lowest part of S (Seminula zone). The Whitehead Limestone,
which rarely exceeds 30 feet in thickness, gives place on the south-
western border of the Forest to a series of dolomite-mudstones, black
and grey crystalline dolomites, and clays with dolomite nodules, of
much greater thickness; but this series does not encroach much on
the Seminula zone.

1 Geology in the Field, Jubilee Volume of the Geologists’ Association, 1910,

. 731.

y ZO EGaSavOlep bain 2524509 Oar
3 Phil. Trans. Roy. Soc., vol. ccii, B, pp. 270, 277, 1912.
4 GEOL. MaG., N.S., Dec. V, Vol. IX, pp. 417-22, 1912.

Cae

Geology of the Forest of Dean. 25

The upper portion of the Carboniferous Limestone of areas to the
south is represented in the so-called Millstone Grit of the Forest of
Dean. This Millstone Grit, which succeeds the Carboniferous
Limestone quite conformably, is mainly, if not entirely, a formation
of Lower Carboniferous age. The name Drybrook Sandstone was
applied to it in 1912.

Thick bands of limestone and dolomite appear in the Drybrook
Sandstone on the south-western margin of the coai-field. Near
Milkwall oolitic limestones in the lower part of the formation have
yielded Semenula ficordes, Cyrtina carbonaria, and other fossils of the
main Semiula zone (S2). Cyrtina carbonaria has also been observed
in corresponding beds of dolomite in the Parkhill adit (Fryer’s
Level). The lower portion of the Drybrook Sandstone may, there-
fore, be correlated definitely with the main Seminula zone of the
Carboniferous Limestone. Unquestionably, the Drybrook Sandstone
passes laterally into limestones as we proceed from the north-eastern
margin of the Forest of Dean southwards to Chepstow and Bristol.

Concurrently with the development of limestones the arenaceous
beds, which compose the bulk of the Drybrook Sandstone even on
the south-western margin of the coal-field, become finer in grain
when followed south-westwards. For example, seams of quartz-
conglomerate are conspicuous in the Drybrook Sandstone of the
Mitcheldean district, but these have dwindled to insignificance in
the neighbourhood of Bream. Bands of shale and fine-grained
sandstone, containing shreds of coal, are found in the upper part of
the Drybrook Sandstone in the Parkhill adit.

Owing to overstep by the unconformable Coal Measures the
Drybrook Sandstone is wholly concealed both on the south-east
between Lydney Park and Staple Edge Wood, where the Carboni-
ferous Limestone also is concealed, and on the north between
Drybrook and Lydbrook Valley. From the same cause the apparent
thickness of the Drybrook Sandstone varies greatly, and in no
regular manner, along its outcrop. The thickness is at least
650 feet in the Soudley Valley between the Shakemantle Pit and
Staple Edge Halt, where the upper beds are well exposed on the
railway.

The Coal Measures of the Forest of Dean lie unconformably, and
sometimes with great discordance of dip, upon an eroded floor formed
by the Drybrook Sandstone, the Carboniferous Limestone, and on the
south-eastern margin of the coal-field, the Old Red Sandstone.

This important unconformity is due to an intra-Carboniferous
episode of erust-movement, folding, and denudation which followed
the deposition of the Drybrook Sandstone, but preceded the formation
of the existing Coal Measures of the Forest. The latter were
deposited on the denuded edges of the older strata. An altogether
later movement involved the Coal Measures, gave them their present
basin-like arrangement, and served also to accentuate the folding
previously imposed upon the older rocks.

The intra-Carboniferous disturbance responsible for the uncon-
formity necessarily involved the Silurian and the Old Red Sandstone,
together with the Lower Carboniferous strata. It produced the

{ y

26 Notices of Memoirs—Professor T. Franklin Sibly—

main uplift of the May Hill anticline lying immediately east of the
Forest of Dean. North-and-south folding predominated, but was
accompanied by some east-and-west folding. The result was a basin,
markedly unsymmetrical in structure, on the site of the present
coal-field. Along what is now the eastern edge of the coal-field the
Lower Carboniferous strata were involved in the western limb of the
May Hill anticline, and acquired a steep dip westwards, the larger
part of the very steep dip that they possess to-day. Westwards
across the site of the present coal-field, away from the May Hill
axis, the intensity of folding diminished very rapidly, and on the
western side of the basin the inward dip of the strata was very
slight. Consequently, the beds of the Coal Measures are nearly, but
not exactly, accordant with the underlying strata on the western side
of the present coal-basin, but markedly discordant with them on the
eastern side, But, slight though the discordance may be on the
western side, the behaviour of the outcrops supplies convincing
evidence of unconformity all around the coal-field. The base of the
Coal Measures pays no regard to the strike of the Lower Carboniferous
beds, but everywhere passes to and fro, slowly or rapidly, across
their outcrops.

Two interesting and significant features are (1) the development
of conglomerates at the base of the Coal Measures, and (2) the con-
cealment of the Trenchard Coal and the measures beneath it by the
overlap of the overlying measures, on the south-eastern border of the
coal-field. These may be described in connexion with the uncon-
formable overstep of the Coal Measures.

The lowest beds of the Coal Measures, those underlying the
Trenchard Coal (Upper Trenchard Coal in some parts of the coal-
field), were termed 'renchard Measures by the late H. D. Hoskold.*
The Trenchard Measures, although variable in character, usually
consist largely of yellow grits, in part fine-grained, compact, and
well-bedded, in part coarse-grained, friable, and imperfectly
stratified. The intercalated clays are sometimes mottled in purple
and yellow. A characteristic feature of these grits, particularly in
the coarse-grained and conglomeratic varieties, is the abundance of
an indurated, white or yellow clay cementing the grains. Om the
northern and north-eastern borders of the coal-field these grits of the
Trenchard Measures often become very coarse-grained and pebbly at
their base, and bands packed with quartz pebbles or quartzite pebbles
constitute well-defined basal Coal Measure conglomerates.

On the northern edge of the coal-field, between Drybrook and the
Liydbrook Valley, the base of the Coal Measures transgresses the
older strata rather sharply, the Drybrook Sandstone and the upper
beds of the Carboniferous Limestone are concealed, and the grits of
the Trenchard Measures rest directly upon Carboniferous Limestone.
A quarry 1,100 yards east of Ruardean Church shows masses of
coarse, pebbly grit resting upon, and in places ‘‘piped”’ down into,
the dolomites of the Carboniferous limestone. The former extension
of Coal Measures northwards and westwards across the denuded

1 “ Geological Notice upon the Forest of Dean’’: Proc. Cotteswold Nat.
Field Club, vol. x, pp. 123-77, 1892.

Geology of the Forest of Deun. QE

edges of the underlying strata is proved by outliers of ‘l'renchard
Measures. In the large outlier of Howle Hill, represented as
Millstone Grit on the Geological Survey map (sheets 48 S.W. and
43 8.K., Old Series), Trenchard Measures rest directly upon the
Lower Limestone Shales. A smaller outlier on Courtfield Hill,
Welsh Bicknor, not shown on the Survey map, rests upon the Lower
Limestone Shales and the base of the Main Limestone.

The railway-cutting immediately north of Drybrook Halt gives
a fine section of Trenchard Measures resting upon massive sandstones
which lhe in the lower part of the Drybrook Sandstone. The basal
beds of the Coal Measures is here a remarkable pebble-bed with
large, well-rounded pebbles of grey quartzite. ‘his pebble-bed has
been traced some distance north of Drybrook, and has been recognized
in the Howle Hill outlier.

On the eastern edge of the coal-field from Wigpool Common as far
south as the Soudley Valley, the 'renchard Measures rest upon
Drybrook Sandstone. In the Soudley Valley, the railway-cutting
south of Staple Edge Halt exposes the unconformable contact of the
two formations. Conglomerates forming the base of the Trenchard
Measures, and containing fragments of a fine-grained, white sand-
stone which can be matched in the Drybrook Sandstone of the same
cutting, rest upon the Drybrook Sandstone with discordance of dip.
The average dip of the Drybrook Sandstone in the cutting is
50° W.N.W. The conglomerates dip slightly north of west at
about 26°.

South of the Soudley Valley, overstep carries the base of the
Coal Measures southwards, and then eastwards, across fully 650 feet
of Drybrook Sandstone and the whole of the Carboniferous Limestone,
in the distance of barely 2 miles to the southern side of the
Blackpool Valley. The Lower Carboniferous strata maintain a steep
north-westerly dip, rising to 65° in places, as their strike swings
gently from 8.8.W.toS.W. The Coal Measures maintain a moderate
dip a little north of west. The Drybrook Sandstone and the upper
beds of the Carboniferous Limestone are transgressed gradually in
Staple Edge Wood. The bulk of the Carboniferous Limestone is
transgressed very sharply in the Blackpool Valley. On the south
side of that valley the base of the Coal Measures continues its rapid
overstep eastwards until, just north of Danby Lodge, it crosses the
quartz-conglomerates which lie some 400 feet down in the Old Red
Sandstone.

In consequence of this sharp overstep the Carboniferous Limestone
and the Upper Series of the Old Red Sandstone remain wholly
concealed from Danby Lodge to the western side of the Cannop
Valley, above Lydney. In and near Stonebury Wood, north of
Lydney Park, the quartz-conglomerates of the Old Red and the beds
of the Carboniferous Limestone, dipping very steeply westward,
reappear from underneath the cover of unconformable Coal Measures.
The sharp swing of the Coal Measure base here carries it back
rapidly from the Old Red Sandstone on to the Drybrook Sandstone
in Old Park Wood.

The unconformable overstep of the Coal Measures is attended, on

28 Reviews—Geological Survey of Great Britavn.

the south-eastern margin of the coal-field, by conformable overlap.
The Trenchard Coal and the underlying Trenchard Measures are
overlapped by the Pennant Sandstone above them. As a result,
the Pennant comes to rest directly and unconformably upon the
older, steeply inclined strata, and the Trenchard Measures fail to
crop over a considerable part of the distance between Staple Edge
‘Wood and the Cannop Valley. This is abundantly clear at Danby
Lodge, where the Pennant Sandstone, containing the Coleford High
- Delf Coal, transgresses the quartz-conglomerates of the Old Red.
It is confirmed by the section in an old quarry on the northern side
of the Blackpool Valley, which shows the unconformable junction of
Pennant Sandstone and Carboniferous Limestone. The sandstones
in this quarry dip gently westwards. They show lenticles of clay
and a streak of very coarse grit or quartz-conglomerate at their base,
and repose upon the worn, hummocky edges of Ge louuile-ets which
dip north-westwards at about 60°.

To sum up, an unconformity at the base of the Coal Measures is
a dominant feature in the geological structure of the Forest of Dean.
It is evidenced (1) by the overstep of the Coal Measures across the
Drybrook Sandstone, the Carboniferous Limestone, and the Old Red
Sandstone, (2) by a great difference between the prevailing dip of
the older strata and “that of the Coal Measures along the. eastern
margin of the coal-field, and (3) by visible discordance of dip at
exposed junctions of the Coal Measures with Drybrook Sandstone and
Carboniferous Limestone respectively. It is attended by (1) the
development of basal conglomerates in the Coal Measures, particularly
well seen on the northern border of the coal- field, and (2) local
overlap of the Trenchard Measures by the Pennant Sandstone,
whereby the former are concealed along part of the south-eastern
edge of the coal-field.

RAV LHWwWS-

I.—Gronocican Survey oF Great Briar.

Summary or Progress oF THE GEoLocicaL SurvVEY oF Great Brirain
FoR1916. 8yvo; pp. iv +56 and 3figuresintext. London, 1917.
Price 1s. 6d.

S was only to be expected, the energies of the Geological Survey
have been almost entirely diverted into new channels connected
with the War. Ordinary field work and detailed mapping are

_ completely suspended, and the remaining staff has devoted itself to

the investigation of certain pressing problems connected with the

mineral resources of the country. Almost the only exception to this
statement is the continuance of the work of examining bore-holes
now in progress; this information, if not recorded at once, is
necessarily most difficult to recover at a later date. Five volumes of

Special Reports have been published dealing with the occurrence of

certain minerals of economic value, and a further volume is in

preparation on the subject of refractories; these include sandstones,
quartzites, ganister, sands, and fireclays (acid refractories), as well as
the basic rock dolomite. These are used for furnace linings and

dif

Reviews—Geological Survey of Scotland. 29

hearths, moulding sands, silica bricks, fire-bricks, and many other
purposes. In Scotland the examination of the coal-field has been
continued, most of the Highland staff being transferred thither, and
several volumes of special district memoirs have been published or
are in preparation. The Dalry iron-field has also been investigated
in detail as a likely source of further supplies of iron-ore of good
quality. The work of the Chemical Department has Jain chiefly in
the analyses made in connexion with the report on refractories.

The Summary of Progress also contains three important appendices
on deep borings, one in Yorkshire, 7 miles north-west of Doncaster,
the others in Kent and Sussex. ‘The fourth appendix, by Mr. G. W.
Lamplugh, F.R.S., contains a summary of the present state of our
knowledge of the underground range of the Jurassic and Lower
Cretaceous rocks in Kast Kent, including a good deal of information
that has only become available since the publication of the memoir on
the subject in 1911. Some of these results were not accessible till
after the printing of Mr. Baker’s paper on the same subject in
the December Number of the Grotoercan Macazrne. The general
result of Mr. Lamplugh’s work is that the Jurassic and Lower
Cretaceous rocks together form a great, wedge with a northward
apex, lntervening between the Paleozoic floor and the Gault, and
that the northern part of the Wealden anticline is superimposed
upon a syneline of the deeper rocks. This interesting result has
become much more clearly apparent from the later borings, although
it could be demonstrated from the earlier data.

R. H.R:

Il.—GrotoctcaL Survey oF ScornanD.
Tur Economic Grotocy oF THE CrnrRaL CoaL-FIELD OF ScCorLaND.
Description or ArgEA IT. Mem.Geol. Surv. Scotland. pp.iv+89,
with folding maps and sections. Kdinburgh, 1917. Price 4s. 6d.

HE Scottish branch of the Geological Survey is making rapid
progress with the publication of its excellent series of nine
memoirs on the coal-fields of Scotland. ‘Those relating to areas V
and VIII have already been noticed in the Guotoeican Macazine.
The present volume deals with area II, which lies almost wholly
within the county of Stirling, and includes the Coal-measures of
Banknock, Carron, Falkirk, and Slamannan, and the coals and iron-
stones of the limestone coal group of the Plean and Denny districts.
The coal-seams are described with the usual amount of detail, and
from the figures given it is clear that the majority of them come
within the category of thin coals; these, however, will doubtless
be profitably worked in the future with improved methods and
machinery. The Millstone Grit Series of Cumbernauld, Castlecary,
and Bonnybridge includes important beds of fireclay and ganister,
which are now of great and increasing importance as refractories.
Several analyses show that these fireclays are of very good quality
and are likely to be largely developed within a short time. ‘The
raised beaches, alluvium, and peat are also briefly described. ‘The
peat is likely to be of considerable economic value, and indeed was

30 Reviews— Dominion of Canada, Ottawa.

already worked before the War for moss-litter; this industry has
now ceased.

1. SEE

T1].—Domrnion or Canapa, Orrawa.
AnnuaL Report oN THE MineraL Propuction oF CANADA DURING
THE CaLENDAR YEAR1915. By Joun McLeztsu. pp. 364. Ottawa:
Government Printing Bureau, 1917.

O doubt the delay in the publication of this report is due to war
il conditions. It is not, however, so belated as might at first
sight appear, since the more important parts saw separate publication
at a much earlier date, and a preliminary report was issued as early
as February, 1916; moreover, the preface is dated September 21, 1916.
The mineral resources of Canada are very considerable, and are as
yet far from being fully developed. The greater portion of the
present production is exported for consumption or refining outside
the Dominion, while on the other hand considerable quantities of the
products of the mines, after refining or partial treatment, or in the
shape of manufactured goods ready for consumption, are imported.
Nearly half the total output, considered from the point of view of
value, comes from the Province of Ontario, thanks largely to the
richness of the nickel-cobalt-silver minerals of Cobalt, British
Columbia, which ranks second, coming a long way behind. The
whole of the copper, nickel, and silver, and much of the gold is
exported for treatment. It is interesting to note that of the total
amount of mine products exported 72 per cent went to the United
States and 25 per cent to the United Kingdom. Much of the world’s
supply of asbestos is contributed by Canada, and for the dozen years
to 1915 the exports of asbestos have averaged over 85 per cent of the
total shipments; it may be noted that the mineral in question is
chrysotile (fibrous serpentine) and not the asbestos of mineralogists
(fibrous amphibole). The report covers the first complete year of
war, and shows clearly that already the War was having a marked
effect on mining; the iron and steel industry in particular was very
active during the year.
The report is well and neatly arranged, so that reference to it is
easy, and the salient features are readily gr rasped.

ITV.—Summanry Reporr or tHe GeoLocicaL SurvEY, DEPARTMENT OF
Mines, FoR THE YEAR 1916. pp.ix+419. Ottawa, 1917.

fW\HIS large and closely printed volume gives striking evidence of

the activity of the Canadian Geological Survey. Owing to the
War the conditions are necessarily exceptional, and the indoor work
of the department has been considerably hampered by the taking
over of its permanent quarters to afford a temporary home for the
Canadian Parliament after the great fire in February, 1916. The
outdoor work has naturally been largely concerned with the
examination of districts likely to yield products of special value at
the present time. One of the most important of these is tungsten,
which has been found in considerable quantities in the Yukon

Reviews—Ooal-fields and Coal Industry of E. Canada. 31

Territory, as well as in New Brunswick and Nova Scotia. The
present high price has naturally stimulated the development of even
small deposits of the ores, which include both wolframite and
scheelite. In the Lillooet district of British Columbia molybdenite
ore has been found in streaks and veins in a mass of very quartzose
granite and is now undergoing development. The molybdenite
mine of Guyon, Quebec, is also important. Another industry com-
paratively new to Canada is the mining or quarrying of magnesite,
for which there is a large demand in America as a refractory to
replace the magnesite formerly imported from Austria and Greece.
The magnesite deposits of the Grenville district have already been
noticed in this Magazine, and the mineral is also being worked in
British Columbia and other districts. The Californian magnesite
belt appears to extend into British Columbia.

One of the most interesting sections of the Report is that dealing
with investigations for coal, oil, gas, and artesian water in Alberta
and Saskatchewan. As is well known, Western Canada possesses
great stores of lignitic coal, forming one of the largest continuous
coal-fields of the world. This is now undergoing rapid development
following on the advance of transport facilities. ‘The oil and gas-
field of Alberta has now reached a stage of important productiveness,
and the gas is utilized on a very large scale for light, heat, and power
in the cities of Calgary, Medicine Hat, and others. The strata from
which the gas is derived are of Cretaceous age, and the structure is
a broad, low anticline, plunging northwards; the gas-bearing strata
oceur at two horizons at depths on the average of about 700 and
1,000 feet from the surface. In the Medicine Hat area there are
thirty gas-wells, which yield about 88,000,000 cubic feet per day.
Borings to still greater depths have yielded a strong flow of saline
water.

Besides the economic work, the officers of the Survey have carried
out a very large amount of stratigraphical, paleontological, and
general geological investigations in all parts of the Dominion, much
of which is of great interest, but cannot here be mentioned in detail.

Jigs Dele Dave

V.—Tue Coat-FIELDS and Coat Inpustry or Easrern CanaDa :
A GeyneraL Survey anp Description. By Francis W. Gray.
pp. 67, with 26 plates and 1 map. Ottawa: Government
Printing Bureau, 1917.

fYVHIS ably written bulletin contains much of interest both to the

geologist and the economist. The Carboniferous area is all
within the maritime provinces, and is nearly a parallelogram in
shape, the four corners of which are the mouth of Chaleur Bay on
the west, Fredericton, New Brunswick, on the south, Arichat, Cape
Breton, on the east, and the head of St. George’s Bay, Newfoundland,
on the north. The Carboniferous rocks occur on both sides of the
Cabot Straits, and are possibly continuous under the sea. Unlike the
common practice which prevails in the United Kingdom, the United
States, and indeed in other parts of Canada, the mineral rights are

32 Reviews—Mining of Thin Coal Seams, E. Canada. |

in the hands of the Government of the Province. This happy result
came about in a rather curious manner. In 1784, when Cape Breton
was made a separate province, the Privy Council reserved to the
Crown all the coal and other valuable minerals, and had earlier
forbidden the mining of coal, so that the unfortunate colonists had
the mortification of seeing the coal which fell from the cliffs on to
the shore washed out to sea. ‘lhe Crown did not make a wise use of
the Royal prerogative, but leased the mines to the Duke of York, who
happened to be deeply in debt at the time. The lease was eventually
broken in 1857 after considerable agitation. The fortunate result
has been that the mining rights did not fall into private hands.

The estimated amount of the coal reserve of Nova Scotia is less
than 1 per cent of the total reserve for Canada, but, because of
the excellent quality of the deposits, their remoteness from other
coal-fields, and their accessibility, Mr. Gray considers Nova Scotia
will remain the chief coal-producing province of the Dominion for a
long time. At present its output is nearly 60 per cent of that of
the whole of Canada. One of the great difficulties in working the
mines is caused by the ever-present gas, and in spite of all the
precautions taken there have been several bad explosions resulting
in loss of life.

Copious statistics of the various mines are given, and the excellent
index provided renders reference to the report easy.

VI.—Tue Minine or Turn Coat Szams as appLtep to THE EASTERN
Coat-FIELps oF Canapa. By J. F. Ketiock Brown. pp. vill
and 1385, with figures and a coloured map. Department of
Mines, Ottawa, 1917.

T is well known that certain parts of the coal-fields of the eastern
provinces: of Canada contain a large number of thin seams of
coal in addition to the thick ones which are more generally worked.
The Government authorities have very wisely undertaken the con-
sideration of how these may best be turned to-account. The chief
problem to be solved is to determine whether it is most advisable in
the public interest to work all seams together, or to preserve either
the thicker or the thinner seams with a view to keeping up the
supply as long as possible. In this memoir the line of demarcation
between a thick and a thin seam is taken at 3 feet: the lower
limit of possible working under conditions likely to obtain in the
immediate future is taken as 12 inches, in agreement with the
views of the British Coal Commission. After a careful survey of
the whole situation it is recommended that the thin seams should be
worked concurrently with the thicker ones, in order to extend as far
as possible the life of the latter, and that measures should also be taken
to secure co-ordination in colliery- working generally, so as to reduce
working costs and to prevent wasteful competition. A very complete
account is given of the position and thicknesses of all known seams,
together with their depth from the surface. From this it appears
that by far the richest area is in Pictou County, Nova Scotia, where
some of the seams run up to nearly 40 feet. Over the rest of the

Reviews—Recent and Fossil Rupple-marks. 33

coal districts the seams are much thinner, thougn often still con-
siderable, and the total reserve is still large. Unfortunately a large
part of the coal-fields lie under the sea, so that access is rendered

more difficult:
Re HR:

Vil—Recrent anp Fosstzn Rrepre-marks. By E. M. Kryoptz.
Geological Survey of Canada, Museum Bulletin No. 25. pp. 56,
with 33 plates. Ottawa: Government Printing Bureau, 1917.

IPPLE-MARKS are of three distinct types: the first is due to
current action on a sandy bottom, the second to wave action,
and the third to the direct action of wind on sand. Mr. Kindle
discusses very fully the characteristic features of each type, and
illustrates them by means of photographs and profiles of casts of
plaster of paris moulds taken directly from ripple-marks. Many of
the moulds were actually taken under water, at times at not in-
considerable depths, with the aid of ingenious apparatus which the
author had specially designed for the purpose. Geologists will be
grateful to him for his clear exposition of the subject. For the lack
of some such work geological literature contains many references to
ripple-marks which are full of mistakes, A common error is to
suppose that fossil ripple-mark is evidence of shore or shallow-water
conditions. On the contrary, there is every reason to believe that
the action of a storm wind will produce ripple-marks to a depth of at
least fifty fathoms of water. The greatest depth at which the author
has obtained a plaster of paris mould was 27 feet. Again, many of
the so-called ‘‘ mud-flows” which have often puzzled geologists are
really the marks produced by the mutual interference of two or more
currents.

It is interesting to note that whereas the amplitude of dune or
wind ripple-mark shows only slight variation, that of subaqueous
current ripple-mark may vary enormously, depending on the load of
sediment carried and the velocity of the current. Ripples of colossal
size are developed in the Ottawa River during the flood stage over
the broad sand-bar at Duck Island. In late summer they are laid
bare at low water, and the crests of the ridges are seen to be 30 to 45
feet apart and 1 to 2 feet above the troughs. In estuaries subject to
strong currents terrace-like ripples are formed which though of
remarkable size closely resemble ordinary ripple-marks.

VIII.—Sovurn Avsrratra.

A Review or Mrytne Operations In THE Stare or Sour AUSTRALIA
DURING THE HALF-YEAR ENDED Drcemper 31, 1916. No. 26.
Compiled by L. C. Gun, S.M., Chief Registrar and Recorder,
Department of Mines. pp. 91, with 4 plates and map. Adelaide,
OT.

f{\HIS review contains reports on a number of different mining and

prospecting operations in the State of South Australia. Bores
have been undertaken with the object of discovering the westerly
extension of the Wallaroo main lode to the Wallaroo Extended

2

DECADE VI.—VOL. V.—NO. I. 2

34 Reviews—North Queensland Tin-fields.

Leases, unfortunately without good results, though they were
continued through the old crystalline rock to a depth of over
1,000 feet in twocases. Among the special reports, accounts are given
of the working of precious opal in Stuart’s Range in the centre of
South Australia, manganese ores at Pernatty Lagoon, boring for oil
near Robe, and details of various copper-mines, most of which are
not now working.

The precious opal occurs in the Desert Sandstone of Upper
Cretaceous age, as it does in all the other opal-fields of Australia,
which, like the Stuart’s Range field, are all situated just inside the
region, which has a rainfallof 15inches perannum. It occurs in veins
and patches associated with large amounts of common opal, and
seems to have been formed in a similar manner to that in which
surface quartzites and limestones are formed in similar dry regions.
The amount of the precious variety is not large, but good finds are
made. The Pernatty Lagoon manganese deposits seem to be a
valuable field of this metal. The ore, which contains from 64 to 81
per cent of Mn Og, with a certain amount of ferruginous material,
is associated with a dolomite of uncertain age, and is found generally
along the master joints. A considerable quantity of ore has been
raised, and more would be sent away but for difficulties of transport
in a rainless country.

Near Robe a bore has been sunk to a depth of 3,950 feet in search
of oil. The district was the subject of a report in the last review of
mining operations (No. 24). In this report the Government Geologist
reported very unfavourably on the oil prospects, and his conclusions
seem to have been substantiated, since after passing through Tertiary
limestone, with gravels and lignite, and Jurassic carbonaceous shales
to the depth above-named no signs of oil have been seen, except
a little natural gas. Of the copper-mines reviewed, some seem still
to have good reserves of ore; many were abandoned owing to
shortage of labour in the days of the gold rush in 1851, and not owing
to failure of ore supplies. The present time, when the price of
copper is so high, seems to be a favourable opportunity for restarting
some of these concerns.

W.. H- W.

IX.—Nortu Qurenstann TIN-FIELDS.

GroLoey anp Minerat Resources oF tHE Cooxrown Disrricr Tin-
FIELDS (North Queensland, 1914). By E. Crcit Sarnt-Suiru,
A.S.T.C., Assistant Government Geologist, Queensland Geological
Survey. pp. 211, with 3 maps, 4 figures, 59 plates, and 3 plans.
Brisbane, 1916.

fJYHE Cooktown district tin-fields are situated in a hilly region,

about 36 miles long, along the east coast of Queensland, running
south from Cooktown at the mouth of the Annan River. The country
is composed of slates probably of Gympie (Permo-Carboniferous) age,
invaded by large masses of granite, with a few flows of post-Tertiary
basalt and alluvium of two different ages. The tin-ore is found
in the alluyium, both old and new, and is disseminated through

Reviews—Minerals nr Crystalline Limestone. 35

the greisenized granite and associated with small veins of quartz and
tourmaline in the neighbourhood of its contact with the slates.
Lodes of any size are very rare, and tin-ore is never found in the
slates themselves. With the exception of one or two mines, the ore
is exclusively won in open works by sluicing the loose alluvial
material or the granite in situ, where it has been deeply weathered
(sometimes as deep as 100 feet) by the effect of the tropical climate.
The mining, except in the case of the Wallaby Creek Company at
Rossville, is on a very small scale, and the water power is provided
by the local streams, which are led in channels to the site of the
workings. As there is a very distinct wet and dry season these
streams do not always contain water, so that the mining in some
places is confined to the wet season. The Annan River Company,
however, are working on a much larger scale, and have erected
powerful pumping plant, so that they can rely on a constant supply
of water from the lower reaches of the Annan River. This company
between 1911 and 1914 raised over 146 tons of tinstone, worth over
£17,000, and is the only large producer in the district with the
exception of the China Camp group of mines further south, which
produced in the same time 269 tons of ore.

The cassiterite is generally black in colour, but ruby and clear
varieties are found in some localities. he only other mineral
occurring in quantities which can possibly be regarded as payable is
wolfram, of which one or two lodes are known, but this is in very
small quantities.

The field bids fair to continue to produce tin for some long time to
come, but will never be a large producer. The content of ore is
never very great, being as a rule between 13 and 24 lb. to the cubic
yard, but exists in great quantities, and is for the most part easily
mined. Two factors interfere to some extent with the development
of the field, one being the great cost of carriage of materials from
Cooktown and the other the scrub-covered character of the country,
which makes prospecting very difficult.

Wi EE WE:

X.—MINERALS ASSOCIATED WITH THE CrystaLLINE Limestone AT
Crestmore, RiverstpE County, Cattrornia. By A. 8. Haxre,
Bulletin of the Department of Geology, University of California,
vol. x, pp. 827-60. Berkeley, 1917. Price 40 cents.

HIS paper is an interesting contribution to the study of the
thermal metamorphism of limestones of varying composition.

The limestone forms a mass resting on the upper surface of a mass of
igneous rocks and penetrated by dykes. The igneous rocks comprise
granodiorite, quartz-monzonite porphyry, and pegmatite. The total
number of minerals described is about fifty, and it is clear that these
may be divided into three categories, those formed by simple
recrystallization of impurities in the limestone, those formed by
diffusion into the limestone of material from the igneous magmas,
and those belonging properly to the magmas. The limestone is for
the most part fairly pure and has crystallized to a white marble,

©

36. Reviews—Ore Deposits of Environs of Hanano- Yama.

often of very coarse texture, and containing some very remarkable
masses of sky-blue calcite. The origin of this peculiar colour is
unknown. ‘he upper part of the limestone was apparently more
dolomitic, and here. brucite has been largely developed, often in
association with graphite. In the contact zones, where diffusion of
silica has taken place from the magma, the commonest minerals are
wollastonite, vesuvianite, and garnet, with diopside and monticellite.
Some supposed new minerals are described under the names of
wilkeite, riversideite, and crestmorite; the analyses and description
of these are not very convincing, and susest mechanical mixtures of
silicates and phosphates. In close association with the i igneous rocks
are also found axinite, scapolite, and datolite, which belong properly
to pneumatolytic metamorphism. The chief interest of this remark-
able occurrence lies in the fact that it seems to combine in itself
nearly all the types of limestone metamorphism hitherto described.
No indication is given of the age of the limestone or of the
intrusions.

Deus Ee hay)

XI.—Tue Ore Deposits in tHe Environs or Hanano- YAMA, NEAR
THE Town or Opa, Provinck or Nagato, Japan. By Taxro
Karo, Journal of the Meiji College of Technology, vol. 1
pp. 1-95, with 10 plates, 1916.

ROM an exhaustive study of the mining district of Oda, in the

Province of Nagato, Japan, a district which has long attracted
the interest of geologists and mineralogists because of the existence
of contact-metamorphic ore deposits of diverse character and the
occurrence of beautiful specimens of copper minerals—cuprite, native
copper, malachite, and chrysocolla—and of various sulphides, silicates,
and other contact minerals, Professor Kato draws some important
conclusions with regard to certain of the problems confronting
students of contact metamorphism. He considers that ‘‘iron, silica,
various rarer metals, mineralizers, etc., i.e. the greater part of the
elements composing the lime-silicate minerals and the entirety of
ore-minerals of the contact metamorpine: deposits, have been derived
from the emanations from the magma’

Another important point is that the metamorphosing solutions first
expelled from a consolidating acidic magma are siliceous in character,
and are afterwards basic, becoming rich in iron, copper, and other
metals, while still containing some silica; finally, at the end of the
mineralization the solutions are rich in iron, copper, and sulphur,
but contain little silica. The lime-silicates are therefore formed
before the minerals rich in iron, and the sulphides and oxide-ores
appear about at the same time as the andradite and hedenbergite.
Although mineralization in contact metamorphic deposits begins with
the magmatic intrusion and continues up to solidification of ie entire
mass, the formation of the main deposits is confined to the early—the
pneumatolytic and pneumato-hydatogenetic—stages, while subse-
quently occur the hydrothermal alterations of the country rock and
deposition of sulphide ores associated with quartz and calcite, but no
lime-silicates. ‘The paper is well illustrated.

1764 ean

Reviews—Cretaceous Pelecypoda of Egypt. o7

XII.—Creracrkous Pretecypopa or Eeypr.

CATALOGUE DES INVERTEBRES DE L’ H@YPrE REPRESENTES DANS LES
COLLECTIONS DU MusmE DE GoLoGIE aU Catre. Par R. Fourtav.
Terrains Cretacts. 2™e Partie: Moxitusqurs LAMELLIBRANCHES.
4to; pp. vili+109, pls. 7. Cairo: Geological Survey of Egypt,
Paleontological Series, No. 3.

fJ\HE rich collections of Egyptian invertebrate fossils contained in

the Museum of the Geological Survey of Egypt, at Cairo, have
for some time past been submitted to Monsieur R. Fourtau for
determination and description, with the result that three important
monographs have now been published, elaborately illustrated by
lithographic drawings designed by F. Gauthier, the preparation of
which reflects the greatest credit on the author, and also on Dr. W. F.
Hume, the Director of the Survey, under whom the work has been
accomplished.

No. 1 of this series, issued in 1913, describing the Eocene
Echinoidea, was reviewed in the Grotoeitcat Maeazrne for that year,
and No. 2, pt. 1, devoted to the Cretaceous Echinoderms, was noticed
in this journal for 1914. The present memoir, No. 3, forms the
second part of the Cretaceous group of fossils.

The memoir figures and describes 170 -different forms of
Pelecypoda, Neumayr’s classification being adopted with modifica-
tions from the works of Munier-Chalmas, Bernard, H. Douvillé,
and Pervinquiére, and the genera and families are arranged under
the groups Taxodonta, Anisomyaria, Schizodonta, Heterodonta,
Desmodonta, and Pachyodonta. Among the species referred to the
following are regarded as new: Leda perdita, Conrad, var. sinea,
Arca egyptiaca, A. coquandi, Ostrea isidis, O. roachensis, Cardita
roachensis, Lucina dowsoni, Siliqua humer, and Corbula peront.

Following the various descriptions, the author gives a good
analysis of the studies of previous observers, and freely criticizes,
when necessary, their determinations and nomenclature. He is of
opinion that the name best known for a fossil should be preferred
even if it be a nomen nudum, in illustration of which Zittel’s Pecten

Jarafrensis of 1883 may be noted. This fossil, except as a list-name,

was without history so far as literature was concerned until 1898,
when Mr. R. Bullen Newton described and figured Peeten mayer-
eymart, from the Esna Beds of Egypt, which afterwards was
acknowledged to be the equivalent of P. farafrensis; therefore the
name of P. mayer-eymari must be adopted for the Zittelian shell,
although German paleontologists have thought differently, Wanner
having introduced the old nomen nudum in his memoir of 1902, which
is now adopted by M. Fourtau.

In the introduction to his work the author presents us with his
views on zoological nomenclature, from which the following may be
quoted: ‘‘En ce qui concerne la nomenclature, j’ai estimé qu’en
dépit de la loi de priorité, on ne saurait s’en prévaloir contre des
dénominations peut-étre moins anciennes, mais connues de tous et
constituant pour le fossile une sorte de possession d’état-civil, que tous
les codes civilisés reconnaissent aux personnes. Ces exhumations

38 Reviews—Monazite Sand Deposits, Travancore.

de noms désuets ou inconnus parfois de tous, ne peuvent que jeter
le trouble dans la nomenclature, et elles ne sont justifiées que
lorsque le nom usité a été déja préemployé pour une autre forme.”
On similar grounds the genus Roudaireva, of Munier-Chalmas,
1881, is adopted instead of Stoliezka’s Veniella of 1871, which
undoubtedly has priority. It may be pointed out, likewise, that
the original orthography of Arca esnaensis has been altered, without
comment, to A. esnehensis. We consider that the genus Ostrea, of
which many species are discussed, would have added much to its
distinctness if it had been divided up into the well-known genera of
Gryphea, Exogyra, Alectryonia, etc., although it may occasionally be
difficult to place a species through slight overlapping of its characters.
The ‘Tableau Synoptique ”’ furnishes a useful conclusion to this
monograph in which the forms are listed in the order of description,
together with their stratigraphical and geographical distribution.
Four stages of the Upper Cretaceous are recognized, viz. Cenomanian,
Turonian, Emscherian, and Aturian, while the occurrences are
entered under Egypt, Sinai, and other countries. :
It is hoped that many more parts of this ‘‘ Paleontological Series”
may be issued by the Geological Survey of Egypt, although in future
memoirs we strongly recommend the addition of an alphabetical
index of all the species and genera, wherever mentioned in the text,
either as synonyms or otherwise.
There should be a great demand for this volume and those
previously published, being indispensable to the student of
Egyptian paleontology.

XIII.—Repvorr on tot MonazitE Sanp Deposits in TRAVANCORE.
By I. C. Cuacko, State Geologist. pp. 138. Trivandrum, 1917.

IF\HE monazite sand deposits of Southern India have now become of

considerable commercial importance, and the Government of
Travancore has carried out a complete survey of all the known
deposits within its territory. The country rock is mainly composed
of charnockites and leptynites, overlain in places by the Warkalay
beds, which are supposed to be Tertiary and equivalent -to the
Cuddalore sandstones of the east coast. ‘The monazite is found in
the sands of the seashore, which are black in colour, owing to the
presence of much magnetite and ilmenite, together with garnet,
rutile, apatite, and zircon. ‘The total area covered by sands rich
enough in monazite to be worked is estimated at 1,427 acres,
calculated to contain about 17,000,000 tons of monazite. However,
owing to tides, currents, storms, and floods, the total amount of sand
seems to vary considerably from time to time. Some of the sand- -
dunes near the shore are also rich in monazite. The monazite is
undoubtedly derived from the charnockite series: certain pegmatites
are specially rich in this mineral, but it is probably widely dis-
seminated in small quantity. It is believed that it has mainly
passed from the old rocks to the coast deposits by way of the
Warkalay beds and has been concentrated in the modern sands by
the action of rivers and the waves of the sea. It is possible that

Brief Notices. 39

deposits formed in old lagoons may now be covered up by blown
sands and silt: such places would probably repay investigation.

Tee dels 1p

XIV.—Annvat Report or tHe State Grotogist, TkAVANCORE, FOR
THE YEAR 1091 mr. pp. 21. Madras, 1917.

fJVHIS report deals with the re-survey of the southern part of the

State. The formations here found may be divided into the five
following groups: (1) crystalline rocks, (2) laterites, (3) limestones,
(4) the Warkalay formation, (5) the recent deposits. The crystalline
rocks form part of the great charnockite series: they are on the
whole intermediate in composition, containing little quartz. These
typical fresh charnockites are overlain on the higher ground by a
zone of leptynite, in which the felspar is kaolinized and the
hypersthene converted into garnet. ‘The massive charnockites are
cut by numerous dykes of norite. The laterites are chiefly of the
residual type formed from the crystalline rocks. The Warkalay beds
are mostly coarse red and yellow sands, and the argillaceous formation
known as teri probably forms part of this series, which is believed to
be of Cretaceous age. The occurrence of monazite in the Warkalay
and recent formations is dealt with in a separate report. The chief
minerals of economic value, besides monazite, are graphite and
pyrrhotite.

DR delle.

XV.—Brirr Notices.

1. Homa@omorpuy.—A clear exposition of homceomorphy as applied
to fossil Corals will be found in a paper by W. D. Lang in the, Proc.
Geol. Assoc., xxvill (2), 1917. It forms the subject of a demonstra-
tion given to the members on the occasion of a visit to the British
Museum (Nat. Hist.). Mr. Lang deals with—(1) Diagnostic characters
of Corals in general and tests whereby fossil Corals may be known.
(2) Homeeomorphy in general and its meaning when applied to fossil
Corals. (3) Cases of homceomorphy in Corals; homceomorphy
between Corals and Polyzoa; between Corals of different formations,
and between Corals from the same formation; among Alcyonarian
Corals. (4) Connexion between homcomorphy and evolutionary
stages in Corals; ‘‘ Morphic Equivalence” of Buckman; Radicals.
(5) Relationship of Rugose Corals and Hexacorals; homceomorphy
in Jurassic Hexacorals. Altogether an admirably useful paper, to
which the student can refer with advantage.

2. Varro on Sors.—It may be well to recall to those who work
on soils the notes made by Varro in the first century B.c. in his
Rerum rusticarum, of which a new translation was issued in 1912 in
Bohn’s Classical Library (G. Bell & Sons) by Lloyd Storr-Best.
Chapter vi deals with the Soil, chapter vii the Site, and chapter ix
Farm Land. In chapter vii occurs the following passage, so
interesting to a geologist; Cn. Tremelius Scrofa is speaking:
‘‘ When I was in command of an army in Transalpine Gaul—in the

40 Brief Notices.

interior near the Rhine—I came to several districts where neither
vine, olive, nor fruit-tree would grow, where they manured the

fields with ‘marne’ [candida fossicia ereta|, dug from the ground,

where they could get salt neither by digging nor from the sea, but
used instead of it salt charcoal made of the burning of certain
woods.”’

8. Fosstr Insects From Ftrorissayr, Conorapo. — This paper,
by Mr. T. D. A. Cockerell (Proc. United States Nat. Mus., vol. li,
pp- 889-92, 1917), describes five new species of insects from the
well-known Miocene shales of Florissant, but being without figures
they are of little use to the paleontologist.

4. Muyerats or Gramorcan.—Mr. F. J. North has issued a careful
paper on the Minerals of Glamorgan in the Trans. Cardiff Nat. Soc.,
xlix, 1916. Some thirty species are recorded and fully described,
with notes and information of local interest. Special attention is
paid’ to economics, and the paper concludes with a bibliography.
Gold in rounded grains is recorded from the Keuper Marl.

5. Trrrytopon.—A recent examination of the skull of Zritylodon
longevus, Owen, allows Dr. B. Petronievies to give as mammalian
characters: divided roots of molar teeth, multituberculate teeth,
straight and parallel rows of teeth, and no post-frontal bone; as
reptilian characters: divided nares, pre-frontal bone, and frontal
bone not bounding the orbit; while those characters both mam-
malian and reptilian are recorded thus: septomaxillary bones,
terminal position of anterior nares, backward position of posterior
nares, divergent parietals, orbito or alisphenoid (or orbitopalatine ?),
no postorbital bar, and brain-case antero-laterally closed. Some
further preparation of the type skull by Mr. Barlow has enabled
Dr. PRetronievics to come to these conclusions, which he considers
show Ziritylodon to be a direct evidence that the mammals have their

origin in reptiles, most probably in Theriodont Reptiles (Ann. Mag. ©

Nat. Hist. [8], xx, October, 1917).

6. Forxesronn Warren.— Despite the long literature on Folkestone
Warren, it has been left to Mr. C. W. Osman (Proc. Geol. Assoc.,
XXvill (2), 1917) to approach the subject from a mechanical point of
view and elucidate its structure from the recurring landslips,
especially that of December, 1896. Studying the effect of com-
pression on the Gault, the critical slope of Chalk on Gault, types of
movements in the Warren, and the effect of water on those move-
ments, he describes the cross sections and accounts for the origin of
the Warren. Proceeding further, he measures up the Lower Chalk,
discusses the effect of the Ferques axis on deposition, and gives the
thickness of the Gault here and at various places in Kent. The paper
is illustrated by a large-scale section from Folkestone to Dover, and
sections at numerous points at right angles to the coast. A list of

fossils collected from the Chalk Marl is provided by Mr. H. A. Allen.

ni ; \

Reports & Proceedings—The Royal Society. 4

REPORTS AND PROCHHDINGS.

I.—Tux Roya Socrrry.

November 22, 1917.—Sir J. J. Thomson, O.M., President, in the
Chair.

The following paper was read: ‘‘The Pelmatoporine, a Group of
Cretaceous Polyzoa.” By W.D. Lang, M.A., F.G.8. (Communicated
by Dr. F. A. Bather, F:R.8.)

The evolution of this sub-family is considered in detail. In order
to present the facts intelligently, they are marshalled according to
the following theoretical considerations :—

1. The species le along diverging lineages ; towards the bases or
proximal ends of these are forms (radicals) with less calcareous
skeletal matter and less elaboration of structure, and these forms
appeared earlier in geological time; towards their higher or distal
ends are forms with more skeletal matter and more elaborate structure,
appearing later in geological time.

2. The evolutionary tendency was to deposit the increasing
superfluity of calcium carbonate where it least interfered with the
organism’s bionomics; if possible, in such position and shape as
might even be useful to the organism. Sooner or later the race
perished through being unable to cope with its constitutional and
increasing habit of excessive secretion of calcium carbonate.

3. There is a predisposition in radical forms of different lineages
to deposit their superfluous calcium carbonate along corresponding
tracts and with it to build up similar secondary structures.’ They
differ in comparative rate of building and in amount of elaboration,
as well as in details in architecture and ornament. Consequently, (a)
in most cases it is possible to predict the general history of a lineage
from an examination of one of its early terms; and (b) lineages
often present series of homceomorphic forms; while characters
diagnostic of genera, and still more of congeneric lineages, often
appear trivial and of little importance to the organism.

4. The ‘‘Law of Recapitulation’’ holds good in post-embryonic
erowth-stages, not only of the individual but of the colony as
expressed by the individual constituents at successive distances from
its starting-point. In fossil Polyzoa, astogeny (as Cumings called
the development ofthe colony) is more easily observed than ontogeny.

5. Periodicity is displayed by the Pelmatoporine in their evolution.

The relations of the various forms are inferred from their adult
morphology. heir stratigraphical distribution is considered in order
to confirm these relations, though the evidence of stratigraphy can
only be negative; it can contradict a supposed relation, but cannot
affirm it. Finally, astogeny of forms is used to test morphological
results.

Incidentally, results obtained by W.'K. Spencer in his investiga-
tions on evolution of Cretaceous star-fishes are compared and found
generally to correspond with results described in this paper.

42 Reports & Proceedings—Edinburgh Geological Society.

IJ.—Epinsureu Groroeican Socrery.
1. October 17, 1917.—Professor Jehu, President, in the Chair.

‘Sketches of South African Geology.”” By Professor 8. J. Shand,
D.Se., Ph.D.

The major physiographic divisions of South Africa are the Coastak
Plain, the Mountain Barrier, and the Interior Plateaux of the Karroo
and the High Veld.. The Coastal Plain on the west has a width of
some 80 miles, rising gently from the sea-level to the foot of the
mountains. Geologically it is formed of rocks of the Nama System
(Cambrian or Pre-Cambrian), resting upon old metamorphic rocks,
with numerous great granite intrusions. There is no continuous
plain on the south coast, but there are many narrow shelves and
patches of raised beach, testifying to recent movements of elevation.
On the east side the Coastal Plain again becomes a continuous
feature, reaching a great width in Portuguese East Africa, where,
however, little is known of its geological structure. The Mountain
Barrier of the west and south is the folded margin of the Interior
Plateau, but on the east it is the fractured edge of the plateau; that
is to say, the west and south coast ranges are fold mountains, while
those of the east are fault mountains. ‘The former are largely
composed of the hard Table Mountain Sandstone, resting with a
strong unconformity upon the Nama rocks. The age of the able
Mountain Sandstone is deduced from the fact that the overlying
Bokkeveld beds yield trilobites, brachiopods, and lamellibranchs of
Lower Devonian age. On the inner side of the Mountain Barrier the
rocks: of the Karroo System make their appearance and cover the
ereater part of the interior of the Sub-Continent. The lowest
member of this system is the Dwyka Glacial Conglomerate, which
extends from the South-West African Protectorate to Natal, and
from the Transvaal to the south-west corner of the Cape Province.
The higher members of the Karroo System have a more limited
distribution than this, and the uppermost or Stormberg Series is
restricted to the eastern districts, where it caps the Drakensberg
Range. ‘he close of the Karroo period was signalized by great
igneous activity and diastrophism. The folded ranges were elevated
at this time; the Karroo sediments were invaded by basic dykes and
sills, and great outpourings of basaltic lavas took place in the regions
of the Drakensbergen, the Victoria Falls, the Bushveld, and the
Kaokoveld. he concluding event seems to have been the drilling
of the kimberlite pipes, from which diamonds are now obtained.
The deposition of the rocks of the Karroo System occupied the whole
period from Carboniferous to early Jurassic time. Rocks younger
than the Jurassic are only found in restricted areas along the south
and east coasts, where there are patches of marine Cretaceous and
Tertiary rocks.

As regards climate, South Africa shows four fairly distinct natural
regions—one of summer rains in the east and central districts, one
of winter rains in the south-west, a semi-arid region in the north and
north-west, and an entirely desert area extending along the west
coast roughly from the Orange River to Walvis Bay. This Coastal

ab

Reports & Proceedings—Hdinburgh Geological Society. 43

‘Desert of the South-West African Protectorate has a rainfall of less
than an inch per annum, and the strong southerly winds cause
terrible sandstorms. Hvery exposed rock is cut and grooved by the
sand-blast, and loose pebbles are faceted by the same agency and
assume the forms known as eimkanter and drevkanter. Wandering
erescentic sand-dunes or Jbarchans travel ceaselessly northward,
covering up everything that gets in their way. In this inhospitable
region diamonds are recovered from the sand by a number of German
mining companies.

2. November 21, 1917 (issued December 14, 1917).—Professor Jehu,
President, in the Chair.

(1) ‘‘ Descriptions of some new Volcanic Necks near Pittenweem.”
By D. Balsillie, B.Sc., F.G.S.

Immediately to the west of Pittenweem Harbour four small
voleanic necks have been laid bare by the sea. The rocks among
which these occur consist mainly of sandstones, shales, fireclays, and
ironstones, along with a thin band of impure limestone yielding
Entomostraca and Spirorbis that was estimated by Mr. Kirkby to
be about 1,000 feet above the Encrinite-bed. ‘The strata here dip
a little to the north of west at high angles, and appear to have
assumed such a disposition prior to their disruption by active volcanic
forces.
he material fillmg the necks is in the main a non-volcanic sedi-
mentary débris, but includes frequent pieces of a highly vesicular
white trap. Neither is there discernible assortment of the con-
stituents in any of these fragmentary accumulations, nor are
alteration effects conspicuous. It appears probable, therefore, that
we have here a record of only a transient manifestation of volcanic
action.

(2) ‘The Glossopteris Flora.””’ By D. Balsillie, B.Sc., F.G-.S.

The apparently cosmopolitan floras of Upper Devonian and Lower
Carboniferous times constitute, as emphasized by Seward, one great,
phase in the evolution of the plant kingdom. These floras included
representatives of all the major classes of our present Pteridophyta,
along with other types now entirely extinct or represented only by
greatly diminished forms occasionally of the most restricted
distribution.

Passing to Upper Carboniferous and Permian times, there is strong
evidence to show that the earth’s surface was then divisible into two
great botanical provinces of ecological significance. In the northern
hemisphere the vegetation might be regarded as merely a continuation
of the older flora, but enormously amplified and extended. In the
southern hemisphere, however, a totally new assemblage of types
appeared, filicinean (pteridospermic?) mainly in the character of
its foliage, and including as two characteristic genera Glessopteris
and Gangamopteris. It is this great series of southern forms that has
been designated the Glossopteris Flora.

Typical members of this southern flora have been recorded from

44 Reports & Proceedings — Mineralogical Society.

Permo-Carboniferous rocks in all the principal land areas of the
southern hemisphere—India, Australia, South Africa, and South
America. The obvious method of explaining this remarkable dis-
continuous distribution is to assume that there were at one time land
connections between these areas, and, indeed some writers have gone
so far as to suggest that there formerly existed a great east-and-west
continent crossing the site of the present Indian Ocean. To this
last: continent Suess gave the name Gondwanaland.

Why should the vegetation of Gondwanaland have been peculiar?
In explanation of this the author made reference to the Talchir rocks
of India, the Bacchus Marsh conglomerates of Victoria, the Dwyka
conglomerate of South Africa, aud the Orleans conglomerate at the
HH of the Santa Catharina rocks in Brazil. All these strata, which
are in intimate association with the plant-bearing beds, afford
indisputable evidence of contemporaneous glacial action in late
Paleozoic times. Geologists, therefore, believe that it was the
secular climatic change accompanying this Permo-Carboniferous
glaciation that impressed itself so remarkably upon the vegetation of
Gondwanaland, extirpating the older lepidophytic types and giving
birth ultimately to the Glossopteris Flora.

JIJ.—Mivrratoeicat Socrery.
Anniversary Meeting, Movember 6.—Dr. J. W. Evans in the Chair.

The following were elected Officers and Members of Council:
President, Mr. W. Barlow, F.R.S.; Vice-Presidents, Professor H. L.
Bowman, Mr. A. Hutchinson; Treasurer, Sir William P. Beale, Bart.,
K.C., M.P.; General Secretary, Dr. G. T. Prior, F.R.S.; Foreign
Secretary, Professor W. W. Watts, F.R:S.; Editor of the Journal,
Mr. L. J. Spencer; Ordinary Members of Council, Mr. 1. V. Barker,
Mr. G. Barrow, Professor C. G. Cullis, Mr. F. P. ee Mr. H.
Collingridge, Mr. T. Crook, Dr. G. F. Herbert Smith, Bria Bleed ok
Mhomas, Mr. H. F. Collins, Ma, J.P. De Castro, Professor te ‘Hilton,
Tientenant Arthur Russell.

The following papers were read :—

Miss E. Smith: On Etched Crystals of Gypsum. Baumhauer
conducted experiments on colemannite and calcite to determine
whether the phenomenon of etched figures is due to lack of
homogeneity or irregularity in the incidence of the dissolving liquid
or to lack of homogeneity in the crystal itself. Further experiments
now made on cleavage surfaces of gypsum tend on the whole to
confirm Baumhauer’s conclusion that the second hypothesis is the
correct one.

Dr. G. T. Prior: On the Mesosiderite— Grahamite Group of
Meteorites. Analyses of the mesosiderite Hainholz and _ the
erahamite Vaca Muerta show that these meteorites do not differ
materially as regards the amount of felspar, and microscopical
examination of other mesosiderites supports the idea that there is no
real distinction between them; the name mesosiderite is therefore
proposed for the whole group. The groundmass of these meteorites
consists mainly of anorthite and a pyroxene, poor in lime and having

Reports & Proceedings—Geological Society of London. 45

a-ratio of MgO to FeO of about 2. he iron and olivine are very
unevenly distributed, and have chemical compositions such as they
have in the pallasites, the iron being poor in nickel (ratio of Fe to
Ni generally greater than 10), and the olivine poor in ferrous oxide
(ratio of Mg O to FeO from 6 to 9). In accordance with the author’s
conception of a genetic relationship of meteorites, it is suggested that
a eucrite-like magma, i.e. one of higher oxidation, was invaded by
a pallasite-like magma of lower oxidation. The curiously unequal
distribution of the nickel-iron and the shattered (cataclastic)
structure which is generally confined to the parts rich in iron
support this view.

Professor H. Hilton: On Changing the Plane of a Gnomonic or
Stereographic Projection. A method was described by means of
which the gnomonic or stereographic projection of a crystal on any
plane may be obtained when the projection on one plane is given.
The application to the drawing or orthographic projection of the
erystal. was also discussed.

Professor H. Hilton: On Cleavage Angle in a Random Section of
aecrystal. A graphical method was given by means of which it is
possible to calculate the chance that the angle between the cleavage-
eracks on a random section of a crystal with two good cleavages may
lie between specified limits. The method was worked out in detail
for the cases in which the angle between the cleavage-planes was
90° or 60°.

IV.—Gerotoeicat Soctery or Lonpon.

November 21, 1917.—Dr. Alfred Harker, F.R.S., President, in the
Chair.

The following communication was read :—

**The Shap Minor Intrusions.’”” By James Morrison, B.A., B.Sc.
(Communicated by Dr. Herbert Lapworth, Sec. G.S., M. Inst. C.E.)

The paper deals with the minor igneous intrusions occurring in
the triangular area between Shap, Windermere, and Sedbergh.

From their field relations and petrographic characters the in-
trusions are found to belong to one or the other of two well-marked
groups, a division which is regarded as connoting also an age-
classification.

The rocks of the earlier set, characterized by the presence of large
orthoclase-felspars of the granitic type, are intimately associated
with the granite, to the immediate neighbourhood of which they are
practically confined. he rocks range from quartz-felsites to lampro-
phyres. Of considerable interest in this group is a series of hybrid
intrusions, consisting essentially of rocks of a more or less basic
magma enclosing xenocrysts of a more acid (but allied) magma
obtained by settlement under intratelluric conditions. The constitu-
tion of any given member of the series is determined by two factors :
the abundance of xenocrysts and the composition of the matrix, an
increasing basicity in the latter (due to original magmatic differentia-
tion) and a decrease in the former marking the successive stages.
The more acid have affinities with the porphyrites, the more basic

46. Reports & Proceedings—Geologists’ Association.

with the lamprophyres, the series ranging from modified biotite-
porphyrites to modified pilitic lamprophyres.

The later intrusions are typically free from the large orthoclase-—
felspars, though quartz-grains may occur even in the basic members.
Associated centrally with the earlier set they are distributed over a
much wider area, overlapping the former in every direction. They
are the result of further differentiation, and are assigned to a later
period when igneous activity was renewed on a more or less regional
scale. The rocks include acid felsites and spessartites. .

The rocks of the earlier set agree in general direction with the
north-north-west fractures transverse to the strike of the country
rock, while the later intrusions trend generally east of north.

V.—Geotoeists’ ASSOCIATION.

December 1, 1917.—George Barrow, F.G.S., President, in the Chair.

The following lecture was delivered: ‘‘The Gold Coast.” By
Albert Ernest Kitson, F.G.S., Director of the Geological Survey of
the Gold Coast.

The features to be considered, after a general description of the
geography and tectonics of the colony, are: the Archean gneisses,
schists, amphibolites, etc., principally of the Eastern Provinces; the
folded and zonally contorted pre-Cambrian, or early Paleozoic,
altered sediments (conglomerates, quartzites, etc.), with interbedded
voleanic rocks (rhyolite, andesite), flanking the former group and
extending westward across the colony; deposits of gold and
manganese.

Intrusions (into both groups) of granites, syenites, diorites,
gabbros, etc.; dolerite volcanic necks; gold, tin, ilmenite, and
molybdenite associated with these rocks.

The slightly inclined sedimentary rocks of the coast (with
Devonian fossils) and of the greater part of Ashanti and the Northern
Provinces with bauxites, oil-shales, and clays; the Tertiary deposits
of Apollonia with bitumen and oil, the ‘‘laterites”” and associated
iron-ores. Fluviatile, estuarine, and eolian deposits.

The evidence of aboriginal occupation, consisting of stone-imple-
ment factories, camps, and crude forts, was also discussed.

CORRESPONDENCE.

ESHA SES
WORM-BORINGS IN ROCKS.

Str, —Dr. Bather’s interesting communication on “ Salt-weathering
and supposed Worm-borings in Australia’? (Grot. Mae., November,
1917) induces me to direct attention to a paper read by the late
Duke of Argyll before the Royal Society of Edinburgh in January,
1889. In this he described similar tubes occurring in some of the
quartzites of Sutherlandshire, and which he and the late Mr. Etheridge
attributed to the burrowing of annelids. Some of these tubes were
horizontal, having been drawn out of the vertical by movements due
to shearing or slipping of the beds or lamine of the deposit.

Correspondence—C. Carus- Wilson. AT

In a communication entitled ‘‘ Pseudo-Scolites” (Research, April 1,
1889) I pointed out that such tubes or ‘“‘ foralites”? might be seen in
great numbers on sloping, sandy beaches, especially when the sand
covers a deposit of shingle, and that they were simply vents formed
in the wet sand by the escaping air, which was compressed by the
advancing waves. Ina given slope of shingle, covered with a layer
of wet sand, there is a certain quantity of air, and this, on being
compressed by an advancing wave, escapes through the wet sand at
the surface. The advance of the wave increases the pressure, and
the confined air escapes from the weakest points at the surface of the
sand. From the vents thus produced the air issues with considerable
energy, as bubbles forced through the water of a retreating wave
often show. The receding tide leaves many of these miniature blow-
holes intact, and frequently with a crater-like ridge of sand around
their orifices. In some cases these tubes were 4 or 5 inches in depth,
and on the more level parts of a beach where firm sand prevailed
they were filled up with fine mud, Foraminifera, and minute frag-
ments of shell, ete. Under favourable circumstances these tubes
might be preserved from future obliteration.

Such tubes might also be formed in unindurated inland deposits by
the escape of compressed gases caused by the decomposition of
organic matter, chemical reactions, and by steam escaping from
heated areas.

C. Canus- Witson.

ALTMORE, WALDEGRAVE Park,

STRAWBERRY HILL.
November 18, 1917.

Nore sy Dr. Baryer.

I must apologise for having omitted all reference to Dr. Carus-
Wilson’s previously published obervations, due, I regret to say, to
pure ignorance of them on my part and presumably also on the part
of Professor Hogbom, with whose account they entirely agree. The
pipe-rock of Sutherland is so well known to British geologists that
it was hardly necessary for me to mention it. Dr. Carus-Wilson’s
reference to it is apparently intended to suggest that the horizontal
position of some of the tubes in the Tasmanian rocks may be due to
subsequent movement. On this point I have no evidence.

F. A. Batuer.

BORING FOR COAL AT PRESTEIGN.

Sir,—The alleged discovery of buried stores of coal at the
Presteign lime-kilns, suggested by Professor Watts (Grou. Mae.,
1917, p. 552) as the origin of the local delusion that a bed of coal
crops out there, is a possible explanation ; but it is remarkable and
lamentable that no tradition of the lime-burning survived among the
unfortunate subscribers. Some such storing of fuel may account
also for the local belief in the existence of coal at Cadwell, 3 miles
E.N.E. of Presteign, where pieces of coal in the soil above a quarry
in Wenlock mudstones and nodular limestones (containing the usual
fossils) were visible in 1915. The coal may have been taken there
to burn lime at some remote period.

48) Correspondence—T. C. Cantrill—J. Reid: Motr.. .

Although well aware of the interesting paper on'the Old Radnor ~
district by Professor Garwood and Miss Goodyear, I refrained from
alluding to it, because it bears on a different locality, and (to judge
by the abstract) deals more particularly with an abnormal facies of
the Woolhope Limestone—a matter with which I was not concerned.
My reason for quoting the earlier authorities was to show how com-
pletely the so-called practical men who ‘promoted the scheme had
ignored what was already known about their own neighbourhood.

T. C. Canrritt.

28 JERMYN STREET, S.W. 1
December 13, 1917.

THE KYSON MONKEY.

Str,—In an important paper published recently by Professor
Boswell in the Journal of the Ipswich and District Field Club (“‘ The
Geology of the Woodbridge District, Suffolk’), vol. v, pt. 1, pp. 1-12,
it is stated (p. 1) in reference to the Eocene sand of Kyson, near
Woodbridge, that ‘‘ Prestwich found the remains of a monkey
(Macacus eocenus) in this bed’’. This, however, is incorrect. In
Owen’s British Fossil Mammals and Birds (1846), on p. 3, he wrote:
‘‘The fossils manifesting quadrumanous characters were. discovered,
in 1839, by Mr. William Colchester . . . in the parish of Kingston
—commonly called Kyson—in Suffolk.”

A further reference is made to this discovery in the Memoirs of
the Geological Survey (Lhe Geology of the Country around Ipswich,
Hadleigh, and Felixstowe). On p. 26, in describing the Kyson beds,
it is stated: ‘‘ . . . the section was exposed in 1839 at the brick-
yard at Kingston or Kyson” ; then follow details of the section and
a list of the Eocene mammals found. Amongst these is mentioned
“* Hyracotherium cuniculus, Owen (first. called MJacacus eocenus)”
Lower down on p. 26 it is stated ‘‘ The complete section is given by
Prof. Prestwich, from whose paper the above details are given’.
Finally, on p. 143, appears the following: ‘‘145. Owen, (Sir) R.
‘On the Hyracotherian character of the Lower Molars of the supposed
Macacus from the Kocene Sand of Kyson, Suffolk’: Ann. Nat. Hist.,
ser. 3, vol. x, p..240.”

It thus seems clear (1) that the so-called Macacus remains were
not found by Prestwich, but by Mr. Colchester; (2) that further
examination of these remains established the fact that they were not
referable to Macacus at all, but to Hyracotherium cuniculus; and
(3) that Professor Prestwich made the foregoing facts clear in
a paper published by him in 1850 (Quart. Journ. Geol. Soc., vol. vi,
pp. 272, 273).

As there are apparently some investigators who still believe that
quadrumanous remains have been found in the Eocene of Suffolk,
I venture to bring this matter before geologists so that the error may
be eliminated.

J. Rem Morr.

November 26, 1917.

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FEBRUARY, 1918.

@ rile ae aa Nae SS

I. ORIGINAL ARTICLES. Page Ill. REVIEWS...“ "> “tige
. Eoeystis, I. Hocystites priunevus James Geikie, the Man and the
Hartt. By F. A. BATHER, M.A., SUGeolOetStse<ecnuke sept smacse cect 83
D.Se., F.R.S. (Plate V and Fossil Echini, Panama Canal ....., = 85 |
Ge PSITOIINES Fab rcare vole seers eerata 49 | Dr. Tempest Anderson’s Voleanic |
South Staffordshire Fire-clays. By. Studies in Many Lands. By |
“A. HuBERT Cox, M.Sc., Ph.D., Professor I’. G. Bonney....:....... 86 |
ENCES cc RU an eeu bs anon erase 56 | Moonta and Wallaroo Mining
~The Lias of South Lincolnshire. Districts in South Australia By |
By A. E. TRuEMAN, M.Sc., 1 il sp ARNC sce an einai Hoppa wea aastae Sou
F.G.S. (With two Text-figures.) 64 | |
The New Brachiopod Genus, Lio- IV. REPORTS AND PROCEEDINGS.
thyrella, of Thomson. By J. j eat f
WILFRID JACKSON, F.G.S. ...... 73 | Geological Society of London—
The Kaolin Veins (Singapore). By ee. ty LET se ieaieaen pes ae
Lieut. J. B. ScrRIVENOR, M.A., Pe ae i ean see re Saree Oy ha 32
1 (CIS She tha ea fate Oe 79 Edinburgh Geological Society ...... 93
5 Mineralogical Society.....:.;,.......-. 94 HY
II. Novices OF MEMOTRS. :
: Sinters 5 ; VY. OBITUARY.
Martin Simpson, a Yorkshire es 5 2
Genlonist er ic otters x hia gg | William Albert Parker, I'.G.S....... 95
The Mineral Resourcesof the British fie foie
MUPPET DING. <.2ciyscsncgscuesaneeedugecs eos 82 VI, MISCELLANEOUS.
Age of the Bolivian Andes............ 83 | Myr: R. Bullen Newton, F.G.S....... 96
West Australian Foraminifera ...... 83. |: Mr. F..W. Rudler, 1.8S.0., F.G.8.. 96

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ORIGINAL ARTICLEHS-

].—Eoeystis, |. Kocysrires priuazvous Harrr.
By F. A. BATHER, M.A., D.Sc., F.R:S.
(PLATE V.)
(Published by permission of the Trustees oi the British Museum.)

\HE second edition of J. W. Dawson’s Acadian Geology (1868)
contains some notes communicated by C. F. Hartt. One of
these, on p. 643, runs as follows :—

‘« Hocystites primevus, Billings, Coll. Hartt (Fig. 220). The little
plate with radiating sculpture, represented somewhat enlarged in
the figure, is regarded by Mr. Billings, to whom the specimens have
been submitted, as indicating a new genus of Cystideans.”’

In this perfunctory manner, without diagnosis or description, was
the genus Hocystites founded. Since a named species was mentioned,
that species, #. primevus, must be taken as genotype, and the generic
name 1s thereby validated.

Kocystites primevus again depends solely on the accompanying figure
220 (our Plate V, Fig. 1). Slight though this may. appear, it does
represent a plate of peculiar and recognizable shape. The holotype,
which was said to be in Hartt’s collection, was one of a series of
specimens from the ‘‘ Primordial Group” of St. John, New Brunswick,
a group since referred to the Lower Cambrian. ‘The specific name
therefore may be accepted, and unless the plate can be shown to
belong to some previously described genus and species, we must
regard Hocystites primevus as representing an actual independent
zoological entity.

It so happens that Dr. G. F. Matthew, of St. John, New Brunswick,
formed the opinion that the plates known as Hocystites primevus
were more properly referable to Zrochocystis. He did not publish
a definite statement to that effect, but he twice suggested or recorded
the existence of Zrochocystis in Canada, namely, in 1896, ‘‘ Faunas of
the Paradoxides-Beds in Eastern N. America”? (Trans. New York
Acad. Sci., xv, p. 207), and in 1899, ‘‘ The Cambrian System in te
Carmela Valley” (Trans. Roy. Soc. Canada, ser. Ir, vol.
sect. 4, p. 128). his latter refers to ‘‘a single discoid plate”’ fe
Division 1 5 of the Cambrian at Long Island, Kennebecasis Bay,
Nova Scotia.

DECADE VI.—VOL. V.—NO. II. 4

50 Dr. F. A. Bather—EHocystis.

- It was when I asked Dr. Matthew for the evidence on which he

recorded this Central European genus from the other side of the
Atlantic that he replied (in litt., February 5, 1900): ‘‘I may say
that the evidence is not direct. Hocystrtes is founded on single star-
shaped plates. ‘With these occur a few elongated plates somewhat
rectangular. The greater abundance of the star-like plates led me to
infer the probable presence of some such genus as Zrochocystites, as
the form to which the two kinds of plates belong.”

The name 77 ochocystites first appeared in print in 1859 (J. Barrande,
Bull. Soc. Géol. France, ser. 11, vol. xvi, p. 543), but then only as
a nomen nudum, and without a species. In 1860 De Verneuil &
Barrande (ser. cit., vol. xvii, p. 537) published a description, and
took as genotype the Bohemian species 7. bohemicus Barrande, of
which no other description had till then been published. ‘The fossil
from north of Sabero, Léon, Spain, which they figured (pl. viii,
figs. 1, la), was referred to that species ‘‘avec réserve’’; it most
probably belongs to 7. barrandei Mun.-Chalmas & Bergeron.

If, then, Dr. Matthew’s opinion is well founded there would follow
the unfortunate result that Zrochocystis (-ites), as the name of a genus
with'a clearly understood genotype, would have to yield to Hocystvs
(-ctes), based on a species that depends in its turn on a single obscure
plate. It is therefore advisable to subject Hocystites primevus to more
critical examination than it has yet received.

There are, of course, more important reasons for undertaking such
an inquiry. Plates from the Cambrian rocks of widely separated
parts of the world have been referred to Hocystis, and the name has
also been doubtfully applied to a fairly well-preserved fossil cystid
retaining its brachioles—¥Z. (?) longrdactylus Walcott (1886). .

That I have been able to make this study is due to the kindness of
Dr. G. F. Matthew, who sent me forty specimens referred by him to
E. primévus, and considered by him to afford the most complete
representation of that species. Eleven of these have, through the
generosity of Dr. Matthew, been retained for the British Museum,
and registered E 7602- 7612.

The specimens are labelled ‘‘ Lower Gamitian Division 1, C, 2,
Paradoxides-beds; St. John, N.B.”’, except three, said to come from
‘Ratcliff’s Millstream”.

The matrix of all is a hard irregularly fissile shale, varying in
colour from dark grey to olive green, and weathering brown. The
substance of the fossils is either much decayed or entirely dissolved
away, and the moulds or impressions are often stained with iron
oxide. The shale has been subjected to some lateral pressure, so
that in several cases the impressions are distorted.

The impressions referred by Dr. Matthew to #. primevus are
divisible into four groups; the numbers of the British Museum
representatives are quoted, as well as the letters which I attached to
Dr. Matthew’s specimens.
‘1. Stellate plates, the typical Hocystites primevus, E 7602-5.
K 7611-12; G. F. M. a, 6, e, f.

2. Plates with marginal pores. EK 7608; G. F. M.c.

8. Columnals. E 7605-7, E 7602; G. F. M. d, g.

ee ee

Dr. F. A. Bather—LHocystis. 51

-4, Undetermined plates. E 7609-10; G. F. M. A.

There seem no a priore grounds for supposing that all these
specimens belong to the same species, or even genus. Nor is there
any external evidence that they donot. They lie close together on
the same surfaces of shale; at the same time they are never in any
natural juxtaposition, but always occur as isolated plates or ossicles.

These four sets will therefore be described separately.

1. The Stellate Plates are probably to be regarded as thecal plates
of a Pelmatozoan, and since a parallel is to be found only among
Cystidea we may regard the Pelmatozoan as a Cystid.

Each plate has a small, but usually distinct, central umbo, from

which folds radiate to the periphery. The ridges due to these
folds on the outer surface of the plate are more marked than the
corresponding furrows on the inner side of the plate (Figs. 7, 10, 11,
12). The number of folds varies from five to perhaps as many as
‘seventeen (Fig. 6). In many instances three folds, arranged in
Y fashion, are more prominent than the others, and merge into the
umbo. ‘I'wo folds nearly as pronounced are often seen to approach,
or perhaps join, the umbo, one on each side of the Y and at about
right angles to its stem. Thus arise five main folds, which, it will
be noted, are not of necessity pentamerously symmetrical. The
remaining folds do not reach the umbo, but while a few come rather
near to it the rest are mere gofferings of the margin of the plate.
Thus the total number of folds tends to increase with the size of
the plate.

These folds present two points of difference from the folds and
ridges so common on the thecal plates of many Cystidea and
Crinoidea.” First, the rare specimens in which the margin of the
plate is indicated (G. F. M. a, 6) appear to show that the main folds
were directed towards the angles of the plate, whereas the axial
folds of Crinoids and the rhomb-folds of Cystids normally pass across
the sides of the plates, the more prominent among them bisecting
the sides at right angles. Secondly, whereas the minor ridges of
Cystidea Rhombifera and of all Crinoidea except Porocrinus are
parallel to the major axial folds, thus giving rise to the characteristic
rhomb-structure, the folds of Hocystis primeva radiate from the
umbo like the spokes of a wheel. It follows from this that in two
adjacent plates of #. primeva the folds cannot have passed in
a straight line from one plate to anuther. It also seems probable
that the plates cannot have fitted very accurately together, and that,
if in any case two ridges of adjoining stellate plates did lie in the
same straight line, then there must have been smaller irregular plates
filling up the interspaces. A similar, though more definite and
regular arrangement of folds is seen in Amygdalocystis florealis; but
the plates of Macrocystella marie, which, as they lie in their matrix
of Shineton Shale, are strongly reminiscent of Hocystis primeva, may
be distinguished by the axial nature of the folding.

Since not a single stellate plate in Dr. Matthew’s collection
preserves a complete outline the exact measurements cannot be
given. The long diameter varies from 2:5mm. to 6mm., but
perfect specimens may have exceeded this. In the majority of

52 Dr. F. A. Bather—EKocystis.

specimens, as preserved, it is about 5mm. The plates appear to
have been very thin, but thickened at the umbo and folds.

Some recent private correspondence suggests the need for an
explanation that, in using the term folds, I have never meant to
imply that a plate was subjected to any force which threw it into
folds. The stereom was, one presumes, deposited in that shape from
the outset. But it followed the course and structure of the stroma,
and this was usually affected by mechanical stresses.

It is quite easy to see how under these conditions there arose the
hexagonal plating, with folds at right angles to the sutures, common
in normal many-plated Cystids (e.g. Heliocrinus, Aristocystis,

ichinosphera); and the modifications produced by the development
of basal and radial plates, as in Caryocrinus and in normal crincids,
also present no difficulty. But it is not at once easy to see what
stresses led to the irregularly pentagonal plates of Hocystis, in which
pentactiny is superinduced on trisactiny (see. Figs. 2-6). The
following explanation is therefore offered.

If a piece of soft woven tissue be lightly stretched over a frame,
and if a few equal weights be attached to various points in it, then
the tissue will be dragged into folds leading from each of these
weighted points to those adjacent. The direction and pattern of the
folding will depend on the positions of the weight-points.

ASS Ze]
vara
SOK
Ux Tele Pi
INNZAS NIZA
KN KY io

Diagram showing the lines of mechanical stress
supposed to have produced the Hocystis plan
of plate.

The problem before us, then, is to find the weight-points that
would produce the fold-pattern of Hocystzs. The three major lines
of several plates, if plotted on paper, lead to an hexagonal pattern.
This at first sight does not seem hopeful. But we note that the
umbones of the plates, instead of lying at the centres of the hexagons,
lie at the angles, or, in other words, at the nodes where the main
lines of stress meet. This suggests that a hexagonal folding of the

Dr. F. A. Bather—Eocystis. 53

stroma, such as may sometimes be seen in contracting homogeneous
layers, preceded any extensive calcification, and that consequently
the stereom was concentrated at the nodes. On this assumption,
there arises a series of weight-points at the angles of alternating
hexagonal spaces. Inserting these on our plan (Diagr. p. 52), we
now proceed to fill in the other lines of stress that would flow
from such an arrangement. These have been represented in the
diagram with thicknesses roughly proportional to the distances
between the weight-points. ‘Thus a triple line connects the nodes
along the sides of the hexagon; a stout double line connects the
nodes horizontally; a faint double line connects those at the upper
and lower angles, this being emphasized because the pull is intensified
in this direction by gravity ; a stout single line joins the node to the
nearer pair of the remaining angles, and a faint single line joins it to
the pair more remote.

Now take this diagram, worked out on purely a prior? reasoning
this night (December 5-6, 1917), and compare it with the lines of
Figs, 2-6, drawn in 1900 before the problem had been formulated.
Starting from a node there are lines of stress precisely comparable
with the folds radiating from the umbo; and it will be observed
that in the diagram no lines occur between the horizontal lines and
the immediately adjacent main lines, just as the plates are folded
very faintly or more often not at all in those spaces.

So much for the folds; now for the outline. If a circle be
described with the node as a centre, and with radius equal to half
the side of a hexagon, it will represent the tract that would
naturally be calcified if calcification spread uniformly outward from
the node untilit met that spreading from the three adjacent nodes.
Known facts of growth, however, suggest that the calcification
would progress more rapidly along the main folds. Let the points
- where these are cut by the circle be joined by straight lines, and an
irregular pentagon will result. his is shown in the diagram by
dotted lines, but these, instead of being quite straight, are bent
outwards slightly along the minor lines of stress. Thus is produced
an outline agreeing so closely with the outline of Fig. 7 that the
correspondence of theory with fact is truly astonishing.

The plates thus outlined in the diagram do not fill the whole
space; more particularly is there a large free area round the centre
of each hexagon. Probably the minor centres of calcification gave
rise to a number of small intercalary plates.

If there be any truth in the hypothesis here put forward it follows
that the Hocystis plan represents an evolutionary stage previous to
that of the more usual pavement of hexagonal plates. One way in
which the change might have been effected would be the fusion and
growth of the plates about the centre of our supposed hexagon ;
this would produce a series of sub-hexagonal plates each surrounded
by smaller ones, much as in Deutocystis. Or the original pentagonal
plates, as they met, might be forced into a hexagonal shape, coupled
with a strengthening of thefold within the fork of the , ; this would
produce a plate like that of Amygdalocystis, which is not on the
norma] plan.

54 Dr. F. A. Bather—Eocystis.

2. The two specimens labelled ‘‘ Plates showing Marginal Pores”’

are in the form of impressions. One of them (EK 7608) looks strangely
like one-half of the pectinirhomb of a Glyptocystid; but the
resemblance disappears when one examines a wax squeeze of it.
I believe this specimen to be the impression of the sutural margin of
a plate 3-8 mm. long, about -6 mm. thick at the corners, and 1 mm.
thick in the middle of the side; the sutural surface is covered with
slightly irregular vertical ridges, about five to the millimetre, and
these may have been crenelations fitting into corresponding notches
in the adjacent plate. These ridges pass right down to the concavely
curyed margin, which I take to be on the inner side of the plate;
but on the outer convexly curved, or, rather, gabled, side they
stop short, so that the suture, if suture it be, was grooved. In the
middle of the side, however, forming, as it were, the rooftree of the
gable, is a rather large prominent vertical ridge, probably continuous
with an axial fold or ridge. Clearly this impression has nothing to
do with the stellate plates, and there is no adequate reason for
supposing that the plate which made it belonged to the same
organism.
_, The other impression, G. F. M. ¢ (Fig. 8), appears to have been
formed by the folded edge of a plate which had fallen obliquely into
the mud. The space formerly occupied by the plate, having been
subject to less compression, is thicker than usual. The walls of the
eavity are marked by about seven ridges, varying in distinctness, and
passing across its thickness. A squeeze of the cavity indicates that
these ridges correspond to indentations or scollopings in the margin
of the plate, lying between its folds. If several plates of this shape
lay next one another in the thecal wall there would be the appearance
of pores between them. It is quite possible that this is one of the
stellate plates, and that others of them had a similar margin.

3. The impressions referred to Columnals are in the main of two
kinds, long and short. The long ones vary in length from 1 to 3mm.,
with a diameter from 4 to 3 their length. The diameter appears to
be least about the middle; in other words the ossicles were slightly
dice-box shaped (Fig. 15). At each end was a conical excavation
penetrating to a depth about equal to the width of the respective
columnals. In the impression this appears as a deltoid patch of
matrix, and is sometimes so pronounced as to give the impression
a bifurcate appearance, G. F. M. g (Fig.14). In a few cases this may
be seen at both ends, but more often the matrix has been split
obliquely to the long axis of the columnal, so that in a single half of
the impression this cone appears only at one end. ‘The sides of the
columnals seem to have been marked with irregular vertical strie,
perhaps due to the original fascicular structure of the stereom
(Fig. 10, 8).

The short columnals leave an impression that approaches a square,
but has the two sides slightly inflected. E 7607 has a length of
about ‘75 mm. and shows no cone at the ends. One of Dr. Matthew’s
specimens (d, Fig. 18) is about :25 mm. long, and has a flattened cone
at each end. rn

There is no direct evidence that these columnals belonged to the

Dr. FA. Bather—EHocystis. — so)

animal that owned the stellate plates. Their association in the rock
suggests that they did so, but the relatively small size of so many
suggests that they did not.

~ On specimen G. F. M. d, a worm-like body, about 11 mm. long and
1:25 mm. wide, and marked with obscure transverse striz, is labelled
by Dr. Matthew ‘‘ Hocystites primeva, stem!” One end lies against
a stellate plate, but there seems no other reason for this ascription.

4. The Undetermined Plates include many obscure impressions and
patches of various sizes and shapes—or rather absence of definite
shape. There seems no reason why some of them should not belong
to Hocystis, nor any why they should. There are several examples
of a trihedral sub-pyramidal impression, probably produced by the
angle of a plate. The wax squeeze drawn (Fig. 19) is taken from
the largest of these (4). Another type is represented by j, the
squeeze of which (Fig. 18) shows curved sides meeting in a rounded
ridge with a wide angle and a rather sharp edge or lip in front.
Other forms are shown in / and /’ (Figs. 16, 20), but without figuring
every specimen one cannot convey an idea of the variations in shape
of these rounded surfaces. Among the fragments is an apparent
spine, /, possibly the infilling of a columnal (Fig. 17). There are
also some minute rounded impressions, which may represent the
intercalary plates of Hocystis.

From the various plates and ossicles now described it is not easy to
reconstruct the form of Zocystis. We can recognize the stellate
plates of the theca and the biconcave columnals, and we are ‘led
by their numbers and their association to suppose that both belonged
to the same form. If this be so, then Hocystis possessed a flexibly-
walled theca borne on a slender flexible stem. One can detect no
obvious brachiolars, and the undetermined ossicles seem too large to
be thus interpreted. Possibly they represent proximal columnals
such as occur in the Heterostelea, to which group Trochocystis
belongs. Comparison may profitably be made with the stem of
Cothurnocystis (Bather, 1913, ‘‘Caradocian Cystidea from Girvan,”
Trans. Roy. Soc. Edinburgh, xlix, pt. ii, No. 6, §§ 200-6,
text-figs. 19-23).

If Eocystis be rightly referred to the Heterostelea, it by no means
follows that it belongs to the Trochocystide. The stellate plates are
unlike the close-fitting hexagonal plates of Zrochocystis (Barrande,
1887, Syst. Sil., Cystidées, pls. iii, iv), and there is no trace of the
characteristic marginals. For similar reasons HKocyst’s cannot be
referred to the Cothurnocystide or Ceratocystide, and still less to
the Anomalocystide. It may have resembled Dendrocystis in the
iregular arrangement of its thecal plates, but it differed in the
eylindrical or dice-box columnals.

For the interpretation of Hocystzs it will therefore be necessary to
consider other forms than Locystis primeva, both such forms as may
have been referred, with or without hesitation, to Kocyst¢/s, and such
obscure remains as may have received yet other names. That inquiry
may form the subject of a future article.

+

56 Dr. A. Hubert Cowa—South Staffordshire Fire-clays.

EXPLANATION OF PLATE V.

Fic. HOCYSTIS PRIMAVA.

1. The Wolotene: reproduced from Dawson’s fig. 220.

2-6. Diagrams illustrating the direction and strength of the folds in vue
plates, viz. (2) E 7611, (3) E7604, both being imprints of the inner
face; (4) G. F.M. f, (5) G.F. M. e, (6) E 7603, these being imprints of
the outer face. In (2) to (5) there are ten folds to each plate; in all
there can be distinguished three main folds A, and two folds nearly as
strong running east and west; subsidiary folds occur in the spaces
between all of these, except the space in the E.S.E. sector (as seen
‘in the external imprint), and are rare in the corresponding W.S.W.
sector.

7. E7602, showing a plate and a columnal; (a) external, (6) internal
imprint. x 4 diam.
8. G.F.M.c. An imprint of a plate supposed to show marginal pores, as
received. X 8 diam.
9. The same imprint after removal of more matrix. x 8 diam.
10. E7602. (a) External imprint of a plate; (b) columnal. x 8 diam.

11. G.F.M.a. Internalimprint of astellate plate of normalform. x 4 diam.
12. G.F.M. 6b. External imprint of a plate. x 4 diam.

13. G.F.M.d. Imprint of columnal(?). x 8 diam.

14. G.F.M.g. Squeeze from imprint of a columnal. x 4 diam.

15. Suggested reconstruction of a columnal in solid section. x 4 diam.

16. F.M. h'. Wax squeeze of an undetermined plate, (a) from above,

G.
(6) from the side. x 4 diam.

17. G.F.M.l. Wax squeeze of an external imprint, possibly the infilling of
acolumnal. x 4 diam.

18. G.F.M. 7. Wax squeeze of an external imprint of an undetermined
plate. x 4 diam.

19. G.F.M.&. Ditto.

20. G.F.M. h. Ditto.

Drawings by G. C. Chubb, from the specimens and from pencil drawings by
the author.

Il.—Nores on some Sourn STaFFORDSHIRE FIre-cLaYsS AND THEIR
Brenaviour on Ienirion.

By ARTHUR HUBERT Cox, M.Sce., Ph.D., F.G.S.

LL geologists are familiar with those changes effected in
argillaceous rocks under the influence of heat from igneous
intrusions, changes that result in the formation of such roeks as
ehiastolite-slate, andalusite-hornfels, etc. It is therefore somewhat
surprising that the changes produced during the artificial heating of
clays should remain comparatively unknown to the body of geologists,
although such changes are produced every day on a large scale
during the baking of clays for the manufacture of pottery of various
kinds. These changes have, indeed, been very little studied from
the mineralogical standpoint. It might at first sight be expected
that any changes brought about artificially by the action of heat on
a clay would compare somewhat. closely with those resulting in an
argillaceous rock when subjected to contact-metamorphism—at any
rate in the normal case of the latter change—when there is no
transference of material from the igneous to the sedimentary rock.
Yet such is hardly the case; there are certainly points of resem-
blance, but there are also very notable differences. It must be made
clear that the clays used in the experiments to be described were

Gon. Maa., 1918. Prats V.

Ws

IK aces

S

y
nt :
4m

EZ i
ZA

Wh
I]

ee

q
Ny

F. A. Bather and G. C. Chubb del. Bale imp.

EOCYSTIS PRIMAEVA HARTT.

er

Dr: A. Hubert Cox —South Staffordshire Pire-clays. 57

selected on account of their importance for certain industrial uses,
and not on account of any special similarity to those argillaceous
rocks usually affected by contact-metamorphism. They are there-
fore clays of a special type with certain chemical characteristics that
distinguish them from the more commonly occurring, and therefore
more commonly metamorphosed, argillaceous rocks. Nevertheless,
the lithological correspondence is close enough to institute certain
comparisons.

Before proceeding, however, to discuss such comparisons of the
artificially induced changes with those occurring during contact-
metamorphism, the characters of the raw material must be briefly
described. The clays subjected to experiment were mostly fire-clays
from the Coal-measures of South Staffordshire. The mode of
occurrence of the origin of the South Staffordshire fire-clays has
been recently discussed by Professor Boulton.’ Fuire-clays differ, of
course, from the commonly occurring clays in their very low alkali-
content, and as a rule also in their lower iron-content. The
particular clays examined were found to consist essentially of
a mixture of two types of material, (1) a fine-grained base or clay-
substance and (2) a larger or smaller amount of arenaceous material.

1. The clay-substance consists of an extremely fine-grained
material; its investigation therefore presents many difficulties. It
is only transparent in the thinnest sections, and is then seen to be
pale-yellow or almost colourless, the colour gradually increasing
with the thickness, so that the material soon becomes yellowish-
brown and almost opaque. It is not quite clear whether the colour
is a property of the material itself, or arises as the result of iron-
staining. Wherever it could be tested the material proved to be
birefringent. In consequence, however, of the very small size of the
crystals compensation occurs in any but the thinnest sections, so that
the material appears to be almost isotropic. By use of the gypsum
plate, however, the double refraction can be made apparent. The
clay material appears, therefore, to be entirely crystalline. It has
often been supposed that the ultimate base in many clays is an
amorphous material, but certainly none of the South Staffordshire
fire-clays examined by the writer showed any clear signs of the
presence of such matter. Further, no amorphous material could be
isolated by means of heavy solutions. When tested in bromoform
solutions of varying density it was found that no material floated in
solutions of specific gravity less than 2°50. On gradually increasing
the density of the solution above that point a slight scum rose to the
surface, but even this proved to be crystalline. There is, therefore,
an entire absence from these clays of material with a specific gravity
less than 2°50. This fact tells strongly against the presence of any
amorphous material, seeing that, whereas (crystalline) kaolinite has
the specific gravity 2°65, the amorphous forms of hydrated aluminium
silicate, such as halloysite, have a density of only about 2:0—-2°2.
If therefore any such substance occurred in the clay its presence
should be easy to determine.

1 Trans. Eng. Ceramic Soc., vol. xvi, p. 287, 1916-17.

Da. Dr: A. Hubert Cox—South Staffordshire Fire-clays. ‘e

It: seems clear, then, that: the clays examined consist entirely of
erystalline material, and that amorphous matter is absent altogether.
On the other hand, Dr. Mellor has recently adduced evidence from ©
the heating-curves of some South Staffordshire fire-clays for the
existence in them of ‘‘clayite’’, which he regards as being amorphous.}
But, as stated above, no amorphous matter could be found De
mineralogical examination.

The mere fact that the clay-base is crystalline and not amorphous
does not, however, prevent the fine material form acting in certain
respects like a colloid. For example, if suspended in water, it may
be readily precipitated by the addition of certain electrolytes,
particularly by acids.

-It is unnecessary for the purpose in view in this communication to
enter into the vexed question as to the actual mineralogical
composition of this clay-base. It certainly seems, however, to act as
a single substance with definite optical characters, and therefore
presumably definite chemical composition. Itis, moreover, significant
_that the more the fine material of a clay can be purified, the more
nearly does it approach kaolin, Al, Os, 2 Si Os, 2 H, O, in chemical
composition. It is true that there are certain marked differences of
appearance between the substance of the clay-base of these South
Staffordshire clays and the kaolinin a china-clay. These differences
appear to be intimately connected with the variation in their plasticity,
the fire-clay being highly plastic, whereas the china- ey 1s. oul
slightly plastic.

2. Arenaceous material was present in all the clays eal
and often in amounts. surprisingly large, considering the typical
argillaceous appearance of hand-specimens. The arenaceous material
consists for the most part of quartz-grains exactly comparable with
those in a normal fine-grained sandstone. Grains other than quartz
are not abundant, but a certain number of chert-grains were usually
to be found. Undoubted felspar was only rarely observed, and the
same was true for clastic micas. Isolated examples of heavy minerals,
such as tourmaline, zircon, rutile, etc., were usually present, but in
amounts so small as to be negligible in affecting the properties of
the clays.

Besides the larger, more or less rounded, and obviously detrital
sand-grains, there were also present innumerable minute flakes and
chips of quartz. These passed downwards into the finest quartz-
dust, almost comparable in grain with the material of the clay-base
itself. It is evident that, owing to its very fine grain it would
prove almost impossible to separate much of this free silica from the
true clay material by any mere process of washing. In view of the
occurrence of chert-grains among the sandy material of the clays,
if seems very possible that some of. this quartz-flour may have
been derived from the disintegration of cherty rocks. On the other
hand, it may have had its origin in the small secondary quartzes
that would result from the alterations undergone by many of the
minerals of the old land surface then undergoing denudation. In

! Trans. Eng. Ceramic Soc., vol. xvi, p. 83, 1916-17.

Dr, A. Hubert Coa—South Staffordshire Fire-clays. 59

any case it is evident that this fine quartz-flour is of true detrital
origin, and not an authigenous constituent arising as the result of
secondary changes in the clay itself.

Among the minor constituents of the clays, carbonaceous menerel
can invariably be recognized in the hand-specimen; this probably
plays an important part in determining the porosity of the burnt
clay. Pyrites occurs dispersed as a fine flour, and a certain amount
of oxides of iron may also be recognized. ~

The first stage of ignition consisted in heating the clay (made
plastic with water and then dried) to a temperature of 1000-1080° C.
for about fifteen minutes. ‘The main changes during this preliminary
heating were: (1) the burning-off of carbonaceous material, (2) the
oxidation of ferrous compounds, involving a colour-change from the
original dark-grey to a paler and more yellowish tint, (3) an almost
complete loss of the combined water. The originally soft clay is
thus converted into a ‘ biscuit-clay”’, as it is termed by the pottery
manufacturers. The biscuit is highly porous, and therefore can
absorb water, but it cannot be reconverted into a plastic material
comparable with the original clay. Some important change has
therefore taken place during the burning, and the biscuited clay has
lost all power to combine with water. Curiously enough this change,
presumably chemical, is not accompanied by any corresponding
change in the physical characters as revealed by the microscope,
although the macroscopic change is obvious enough. ‘The biscuited
clay presents in fact, so far as I could observe, very much the same
appearance under the microscope as the original clay.

When, however, the ignition is carried out at a higher temperature,
about 1500° C., various interesting chemical anal mineralogical
changes begin. The clay now gradually ‘“ vitrifies’’, owing to the
partial fusion of the Jess refractory constituents, resulting in the
formation of material that is practically a glass. The amorphous
nature of the new material is not, however, readily established in the
early stages of the process. ‘he difficulty arises both from the
minuteness of the particles, and the extent to which the newly-
formed vitreous material is crowded with as yet unaltered crystalline
material. Also the glass, as first formed, is in a state of strain, since
the vitrification takes place without the material ever becoming
actually liquid in the popular sense. Accordingly the glass is
birefringent in the early stages of the process. As the heating is
continued, more and more of the original crystalline material Joses
its identity, and the resulting vitreous substance thus has more
chance to adjust itself. This latter factor is, however, partly
counterbalanced by the fact that the newly-formed glass occupies
more room than the crystalline material, as is shown by the respective
densities. Owing to slight flow-movements, a minute, irregular
streakiness soon appears. ‘The strain is thereupon somewhat lessened,
so that the material becomes, over small areas, quite isotropic.

The vitreous material can then be seen gradually to corrode and
absorb even the larger sand-grains, so that an almost uniform product
is finally obtained. As stated above, all these changes take place
without the material ever becoming really liquid, always provided that

60 Dr. A. Hubert Cox—South Staffordshire Fire-clays. —

one is dealing with-a truly refractory clay, and accordingly the ignited
article retains its original shape. The resulting product, in fact,
does not present to the naked eye any marked difference to the
biscuit-clay, save that it appears, perhaps, to be a little more compact.
A careful examination, however, reveals slight traces of fusion
having taken place, and the material no longer tends to crumble
easily as does the biscuit-clay. Actually, however, the specific
gravity is lowered, as is only to be expected when crystalline material
passes over into the amorphous condition.

A high-grade clay will then remain in much the same condition,
even when subjected to considerably higher temperatures, tempera-
tures up to 1600° C., or even in certain special cases up to 1700° C.
Vitrification is naturally progressive, but still the clay does not soften
appreciably until these temperatures are reached. An inferior clay,
on the other hand, under the same conditions melts down more or
less completely, naturally changing its shape completely during the
process. All stages from readily fusible clays to highly refractory
ones may be obtained. It was found that the softening-point of
lower-grade fire-clays was considerably raised if the coarse sand-
(quartz-) grains were first removed by washing. Conversely these
coarser portions from the clay, when treated alone, were found to
have a very low softening-point, becoming quite fluid at the higher
temperatures. This point will be further referred to below.

Returning to the more refractory clays, with increase of tempera-
ture an entirely new change begins, the results of which become
more and more marked the longer the clay is subjected to the higher
temperature. The new change consists in a devitrification of the
glass owing to the separation of tiny needles of some crystalline
substance. This devitrification may set in before the vitrification is
quite complete, in that the larger quartz-grains may not have been
finally absorbed by the fluxing sroundmass. In specimens exposed
to a very high temperature for many weeks the devitrification has
proceeded to a very considerable extent, although it still remains
incomplete. The material so obtained consists of a colourless and
completely isotropic glass enclosing great numbers of small crystals.
The crystals, in fact, : are so numerous and so small as to render the
glass opaque except in very thin section, when the glass appears as
if it contains a vast number of little globules. Under favourable
conditions, and with high powers, the apparent globules are seen to
be really angular, and exceptionally they are seen to be elongated in
prismatic form.

The crystals were isolated by means of cold dilute hydrofluoric
acid, which remained without action on them. ra all’ proved to
be acicular in form, with a high refractive index—about 1:°66—
straight extinction, and + character. They ne therefore, of
a sillimanite. There appear to be no substances present other than
sillimanite and the clear glass. In one specimen, which had been
exposed to a high temperature for many weeks, and in which,
therefore, the crystallization may reasonably be assumed to be
complete, the amount of sillimanite was found to vary between 29:0
and 33:3 per cent.

Dr. A. Hubert Cox—NSouth Staffordshire Fire-clays. 61

The separation of. the crystalline sillimanite, with a specific
gravity 3°23, naturally involves a considerable contraction. The
result is the formation of a drusy material, in which the cavities
are of comparatively large size and quite irregular in shape.

The marked tendency to the production of sillimanite when
substances approximating in composition to kaolin are strongly
heated, has been observed on various occasions. Wernadsky ‘
obtained it from artificial mixture of Al, Os and Si O,, and also from
kaolin. He further noted its formation in crucibles and fire-bricks
from various fire-clays. It was also observed by Mellor? in
porcelains made from mixtures rich in china-clay and felspar fired at
temperatures over 1300°C.3 It is a remarkable point that the
sillimanite formed from the fire-clays seems not to have the same
composition as the naturally-occurring sillimanite of the rocks.
The natural product is always stated to have the composition
Ale Si Os, or Al, Os, Si O2, where the Al, O; : Si Og ratio is as 1:1.
The artificial product, however, seems to have the ratio 11: 8, as
shown by the following figures :—

Calculated for
11 Ale Os, 8 Si Oo | Ale Os, Si O.
SiO, 30-07 | 28-89 29-96 37-03
Al, O; 69°93 | 71-11 70°04 62°97

The analysis was carried out by volatilizing the Si O2 from the
crystals (obtained as mentioned above, p. 62) as Si Fy, the Als O; being
left as such on ignition.

A similar result was obtained by Wernadsky ‘ for sillimanite from
fire-clays, whereas the sillimanite formed from artificial mixtures of
Al, O; and $i0 had the normal composition Al, Si Os, whatever the
proportions of Alz Os and Si Oz in the original mixture.®

Sillimanite of the composition 11 Als Os, 8 Si Oz was recorded by
Sainte-Claire, Deville, and Caron ® as formed by the action of Al I's on
Si Oz, but, so far as I am aware, there is no case recorded of an
analogous product occurring in the metamorphic rocks. The question
is, however, deserving of further investigation.

Sillimanite is a chemically simple substance, and it is well known
that the fusing-point of a chemically simple substance is lowered by
the introduction of impurities. Now all the clays examined contained
sandy (quartzose) material giving an SiO2: AleO,; ratio much greater
than that in sillimanite. It appeared probable, therefore, that the
refractoriness of the clays would be increased by removing the excess
of sand. ‘his was actually found to be the case, as already
mentioned (p. 60). Since, however, the clays all contain much

* Bull. Soc. Min. France, vol. xiii, p. 260, 1890.

* Journ. Soc. Chem. Ind., vol. xxvi, p. 375, 1907.

* For a summary of the effects of heat on kaolin and kaolinite, see J. A.
Howe, Handbook to the Collection of Kaolin . . . (Mem. Geol. Surv.), 1914,
p- 151, with references.

* Bull. Soe. Min. France, vol. xiii, p. 270, 1890.

> Op. cit., p. 263.

® C.R., vol. xlvi, p. 766, 1858.

62 Dr. A. Hubert Cox—South Staffordshire Fire-clays.

free silica in the form of a quartz-flour, the Si O, : Al, O, ratio still
remained in excess of that demanded by eilGnanite. This excess
of silica could not be readily removed by any simple process of
elutriation in consequence of the extremely fine-grained character of
the quartz-dust, the particles of which become comparable in size
with those of the clay-base itself." In order, therefore, to bring the
$i 0. : Ale O; ratio down to that demanded by sillimanite, alumina in
various forms was added to the clays in various amounts. The
refractoriness of the clays was then again found to be further

‘increased, or in other words the Sela was very consider-

ably raised.

Turning now to a comparison of the changes occurring in
artificially heated clays with those in contact- altered ar gillaceous
rocks, there are certain points of resemblance, as is only to be
expected. But there are also, in most cases, some very interesting
differences in behaviour.

In the first place it will be noted that the aluminium-silicate
formed under artificial heating was the high-temperature form

_ sillimanite. In no case was the low-temperature form andalusite

observed, and, so far as I am aware, the artificial production of that
mineral has never been recorded.

In contact-altered rocks, on the other hand, both minerals may
occur, sometimes exclusively the one or the other, sometimes both
together, whereas in yet other cases hyanite is the characteristic
mineral.

Again, the more obviously contact-altered rocks are almost always
holocrystalline, belonging to, or approximating to, the granular
rocks classed as hornfels. Cases of vitreous rocks produced by
contact-action are the exception rather than the rule. We have,
however, examples of such vitreous rocks in the buchites, or vitrified
phyllites, British specimens of which have been described from
Argyllshire by Dr. Flett.?

In these vitrified phyllites, however, the newly-formed aluminium
silicate occurs, not in the pure state as andalusite or sillimanite, but
combined with MgO as cordierite. ‘his, however, is merely the
result of the high magnesia-content of the original phyllite, in which
the magnesia was present in the form of chlorite.

Apart from the buchites certain other examples of contact-
altered rocks are known that match in all respects the products
formed by the continued ignition of fire-clays. They are rocks that
occur as xenoliths in basic intrusive rocks in Mull. A complete
account of the phenomena there shown is not at present available,
but some mention of the rocks has been made by the officers of the
Geological Survey inrecent Summaries of Progress. These xenoliths,

1 Tt has been shown possible to remove this silica-dust by osmosis, a process
that has been claimed to yield excellent results in other cases [W. R. Ormandy,
Trans. Eng. Cer. Soc., vol. xii, p. 36, 1912-13, and vol. xiii, p. 35, 1913-14].
When a suspension of clay is electrolized the quartz remains neutral, the clay-
substance goes to the — pole, while most of the impurities go to the + pole.

2 Geology of the Country near Oban and Desig) (Mem, “Geol. Surv.), 1908,
p. 129, with references.

.
i)

Dr, A. Hubert Cox—South Staffordshire Fire-clays. 68

derived from highly aluminous shales, have been converted into
sillimanite-hornfels, that is, rocks consisting ‘‘entirely of minute
slender needles of sillimanite set in a colourless glassy base’’.! One
such rock has been analysed.

It is noteworthy that these vitrified rocks occur, as a rule, in
association with those basic intrusive rocks, such as olivine-dolerites,
camptonites, monchiquites, etc., that show a tendency to contain
more or less analcite. The magmas that give rise to such rocks,
therefore, must have been richer in water-vapour than is normally
the case in igneous magmas. Accordingly it may well be that the
vitrifying action which they exerted on the surrounding sediments
was facilitated by the presence of the hot vapours. his conclusion
is supported by the analyses quoted by Dr. Flett,? which show an
accession of water to the vitrified rock as compared with the
unaltered rock.

It may well be that the vitrification of the ignited fire-clays was
hkewise facilitated by the presence of slight traces of water that had
escaped volatilization during the preliminary heating to the biscuit
stage. In this connexion it may be noticed that most glassy rocks,
such as the pitchstones and tachylites, show a high water-content.
Obsidians, however, form an exception to this rule.

Summarizing the results we may say that the artificially heated
clay, originally cryptocrystalline in texture, shows first a vitrifica-
tion, followed by a partial devitrification, resulting in the formation
of the high-temperature mineral sillimanite. The texture still
remains very fine-grained.

The naturally heated rocks, on the other hand, do not normally
show signs of any vitrification having taken place. Rather do they
pass into rocks of the holocrystalline hornfels type with a medium
to coarse texture, and in which low-temperature minerals may be
found either alongside, or to the complete exclusion of, high-
temperature minerals. Such contact-action was therefore brought
about by a comparatively small rise of temperature, extending,
however, over a considerable time.

Exceptionally there do occur vitrified rocks comparing more
closely with the artificially altered fire-clays, but such vitrified
rocks are only associated with special types of igneous rocks, and
water-vapour probably played an important role in determining their
special features.

I have to express my indebtedness to Professor Sir Herbert
Jackson, K.B.E., F.R.S., for his most valuable advice and for
reading through this paper, and to the Controller of the Optical
Munitions and Glassware Department of the Ministry of Munitions
of War for permission to publish these results of an investigation
primarily undertaken on behalf of that Department, and carried out
in connexion with Sir Herbert Jackson’s researches on fire-clays for
the Clay Research Committee of the Institute of Chemistry.

1 A. E. Radley, Swmmary of Progress for 1914 (Mem. Geol. Surv.), 1915,
p- 57.
2 Op. supra cit., p. 132.

64 A. H. Trueman—The Inas of South Lincolnshire.

IlI1.—Tar Lras or Sovurm LinconnsHire.

By A. E. TRUEMAN, M.Sc., F.G.S., formerly Research Scholar, University
College, Nottingham.

InrRopucrory.

HE area to be described is that part of the Lias outcrop extending
from Lincoln southwards to Barrow-on-Soar and Grantham,

and includes south-west Lincolnshire and small portions of north-
east Leicestershire and east Nottinghamshire (see Map, Fig. 1).

LINCOLN
Devecenia
Waddington

Bassingham |

Brant Broughto

NEWARK * Ge ee
| ce y Leadenhall

“Cotham Caytho rbe TI

Gonerby

sia Bottesford
a Sedoebrook
| Cotgrave Gorse . Barnstone an *GRANTHAM|

o ry

Woolstho be toga

barre: (Outhor e
- P Plun siersfoxd

CY

nar
Stathern

Normanton Hills
- ne White lain
Bett ‘) Old Dalby”

eBarrow-on-Soar oe Cee
Fic. 1.—Diagram map of South-West Lincolnshire to show the position of
exposures. (Adapted from the Index Map of the Geological Survey.)

The rocks of this district were mapped by the Geological Survey,

and an account of some of them was published in 1885! and 18887;

* The Geology of South-West Lincolnshire (Mem. Geol. Sury.), 1885.
2 Country around Lincoln (Mem. Geol. Surv.), 1888.

A, KH. Trueman—Tie Lias of South Lincolnshire. 65

the south-western part of the area has been resurveyed and described
in more recent memoirs. A summary of the geology of the area
was prepared in 1910 by A. J. Jukes-Browne,' but except for these
publications the literature is scattered and consists mainly of short
papers; details of these are given where they are referred to.

It will therefore be seen that the Lias as a whole has not been
studied in this neighbourhood for some thirty years. During this
time the Lias of other areas has been carefully investigated by
numerous workers, resulting in great advancement in our knowledge
of the succession. This work has been undertaken in order to deter-
mine whether the Lincolnshire succession agrees with that recorded
elsewhere.

Since there are no continuous sections available for study, the
work has been confined to artificial exposures in limestone and
ironstone quarries and clay pits. Many of the exposures examined
by previous writers have long been abandoned, owing to the closing
of the hand-brickyards in the area;* moreover, on account of the
war, many of the remaining yards have been temporarily closed,
and consequently it 1s often a matter of some difficulty to collect
fossils in situ. Thus it may be expected that the faunal lists will
be considerably increased and much fresh detail obtained by further
work when the pits are reopened. While only scattered observa-
tions may be made on the Lower Lias clays, it has been possible to
make a detailed comparison of the Middle and Upper Lias. In the
course of the work samples of clay from each exposure have been
“washed”? and the residue examined for Foraminifera, details of
which are given in the lists.

It is necessary to state that the interpretation of ‘‘ zone”’ adopted
in this paper is that given by Mr. W. D. Lang,* who emphasized the
fact that once a zone is defined its boundaries ‘‘ theoretically are
fixed for ever”’. The so-called zones which have been used at
Lincoln have often been unsatisfactory ; for example, the deposits
known as commune zone in Lincolnshire and Yorkshire are quite
different in age. If zonal terms were correctly used, such a contra-
diction would be impossible. In this paper the hemeral terms
introduced by Mr. S. 8. Buckman, which have sometimes been
miscalled zones, have in the Upper Lias been used as sub-zones of
Oppel’s cumbersome zone of Posedonomya Bronnt.

In the course of this work much help has been received from
numerous workers in Lincolnshire, especially Mr. A. Smith, of
Lincoln Museum, and Mr. H. Preston, of Grantham, who generously
placed at my disposal their detailed knowledge of the district. For
permission to examine specimens I am also grateful to Mr. G. W.
Lamplugh and Mr. H. A. Allen, of the Jermyn Street Museum
(Geological Survey); and to Mr. KE. E. Lowe, of Leicester Museum.
Mr. 8. 8. Buckman has kindly named several ammonites and assisted

! Lincolnshire, Jubilee Vol., Geol. Assoc., 1910.
SAB. Trueman, ** Lias Brickyards i in South-West Lincolnshire ’ : Trans.
Lines Nat. Union, 1917.
* W. D. Lang, ‘*‘ Geology of Charmouth Cliffs, ete.’’?: Proc. Geol. Assoc.,
1914, p. 307.

DECADE VI.—VOL. V.—NO. II. 5

66 A. HE. Trueman—The Lias of South Lincolnshire.

im other ways. Much help in the field has been given by Messrs.
W.E. Howarth and W. D. Varney, while at all stages of my work
Professor H. H. Swinnerton has offered advice and encouragement,
for which I am greatly indebted. I have also to thank Professor
T. F. Sibly for reading my manuscript and making various suggestions.

The general succession of Liassic rocks in this area is as follows :—

Feet.
UPPER Lias. Shales with concretions . 3 about 100
Thickness decreasing northwards.
(No higher beds than the subzone of swbcarimatum
are present at Lincoln, and the subzone of
fibulatum at Grantham.)
MIDDLE Lias. a. Marls and Ironstone (present in South
Lincolnshire. Only thinly represented around Lincoln). 3-30
b. Shales. : : : é : 30-70
Lower Liss. a. Blue, black, and grey shales, with .
nodules and bands of earthy limestones . about 700
b. Hydraulic limestones : : : 25

It will be most convenient to consider the rocks in the following
order :—
1. Hydraulic Limestones.
2. Lower Lias Clays.
3. Middle and Upper Lias.
(a) Lincoln, (6) Grantham.

1. Hypraviic LIMestones.

The number of Hydraulic Limestone quarries now being worked
is considerably smaller than it was a few years ago, but Lias
cement is still made at Barnstone, Owthorpe, and Barrow-on-Soar ;
a large quarry near the railway at Normanton Hills, East Leake,
has only recently been abandoned, and a complete section of the
beds from the Keuper to the Lower Lias is still visible, while the
junction of Rhetic and Lias is also exposed at- Cotgrave Gorse.
The limestone quarries east of Newark have not been worked for
several years, and in only one of these is the succession clear.
However, the construction of trenches at the Royal Engineers’ Depot
at Coddington has made it possible to study the sequence in the
Newark neighbourhood. Colonel H. Jerome kindly gave permission
to study this section.

An examination of the available sections and a comparison of the
diagrams which have been constructed, as suggested by the late
Dr. Vaughan,’ to show the ranges of the fossils, indicates that there
are three types of transition from Rhetic to Lower Lias in this
district, viz. :—

1. The type seen at Owthorpe, a full account of which was given in
a previous paper;* it was pointed out that the lowest beds do not
contain Psiloceras planorbis, the zonal ammonite, which is likewise
absent in the lowest beds at Cotgrave Gorse, Normanton Hills,
Barnstone, and Newark. T. Wright noticed that in the South of

1 A. Vaughan, ‘‘ Lower Beds of the Lower Lias of Sedbury Cliff’: Q.J.G.S.,
vol. lix, p. 396, 1903.

* A. E. Trueman, ‘‘ Fauna of the Hydraulic Limestones’’: GEOL. MaG.,
Dec. VI, Vol. II, p. 150, 1915.

A. BH. Trueman—The Lias of South Lincolnshire. 67

England also the lowest beds of the Lias did not contain any
ammonites,’ while the numerous sections recorded in the Memoirs of
the Geological Survey indicate that this condition is of frequent
occurrence.* Indeed, it has been suggested that these lowest beds
should be considered as of pre-planorbis age,®> and called ‘‘ Pleuromya
and Ostrea Beds’’.4 Their age and relationships were discussed in
the paper referred to.

2. At Barrow-on-Soar Psiloceras planorbis occurs in beds which
are the equivalent of the so-called pre-planorbis beds of other
localities.

3. The third type, associated with the Sun Bed, seen at Cotgrave
Gorse, has indications of a slight break in sequence at the top of the
Rheetic.

The first type of transition from Rhetic to Lias may be seen
at Owthorpe, Barnstone, and near Kast Leake, where the sections
all conform more or less to the following :—

Feet.

Angulata { Dark-blue shales with Selenite crystals and with rare
zone. {limestone nodules, with Schl. angulata . : he)
Dark-blue shales : ‘about 9

“*Root Bed,’’ a massive bed of yellow earthy limestone
with Lima and P. planorbis . 1

Flagey beds; fissile limestones or shales with abundant
Planor bis C. Johnstont 5 2
zone. Earthy limestone and shales with P. ‘planorbis 3
& without nA 2
Fine blue limestone with Oyster Beds and Pleur omya : 2

Hard blue shales with el limestones and Mcdiola
minima : s é : 5 5)

The beds with Conon nelle were not seed eeepe: at
Barnstone, where they may be seen at the south-eastern end of the
quarry. The sections at Coddington, in the trenches two miles east
of Newark Church, show about 20 feet of hard limestones and shales
belonging to the planorbis zone. The upper beds in this district are
much coarser than those in the south of the county, but the section
does not. differ in any essential points from that noted by Wilson® in
the same neighbourhood at Cotham.

Only one section of Lower Lias can now be examined in the neigh-
bourhood of Barrow-on-Soar, and this is situated north of the
railway near Sileby, one and a half miles west-south-west of Barrow
Church. The details are similar to those given by H. B. Woodward °
and M. Brown.7 Comparing these two interpretations, it will be
noted first that Brown assigned to the Rhetic certain beds, about

1 T. Wright, ‘‘ Lower Lias and Avicula contorta zone’’: Q.J.G.S., vol. xvi,
p. 374, 1860.

2 See, for example, H. B. Woodward, Lias of England and Wales (Mem.
Geol. Surv.), 1893, pp. 137, 141, 145.

3 L. Richardson, Geology of Cheltenham, 1904, p. 38.

Tsetse Buckman, Yorkshire Type Ammonites, vol. i, p. xvi, 1910.

° E. Wilson, Geology of South-West Lincolnshire (Mem. Geol. Surv.), 1885,
16 Ale
6° H. B. Woodward, Lias of England and Wales (Mem. Geol. Surv.), 1893,
p. 169.

7 In Geology 0 Country near Leicester (Mem. Geol. Surv.), 1903, pp. 22-3.

68 <A. HE. Trueman—The Lias of South Lincolnshire.

4 feet in thickness, which Woodward had considered as Lias. These
are unfossiliferous earthy limestones and shales, unlike those usually
found in the Rheetic, and are probably of Liassic age, but the absence
of a continuous section in this neighbourhood makes it undesirable
at present to give a definite statement. Even if these beds should
prove to be the equivalents of the lowest beds elsewhere, the entrance
of P. planorbis must have been distinctly earlier at Barrow than in
any of the other localities examined.

It will be further noticed that in Brown’s table the ‘ Roof Bed oF
at Barrow is included in the angulata zone, although Woodward, who
did not attempt to separate the planorbis and angulata zones, had
previously recorded P. planorbis from the same bed. As a matter of
fact, the lowest definite occurrence of S. angulata is some. 10 feet
higher. Brown apparently considered ‘‘ Schlothevmia catenata’’* to
indicate the lower part of the angulata zone, but this is doubtful;
Wright inferred that his example. of ‘‘ 8. catenata”’ from Barrow
was from the planorbis zone,* and Hyatt also showed that
‘< §. catenata”’ most frequently occurs in the upper part of the
planorbis zone on the Continent.’

Further, it must be noticed that the Roof Bed of Barrow is almost
identical in lithology and fossil content with the bed at Barnstone
and elsewhere, to which I have applied the same name, and that in
these places P. planorbis occurs above this level. There seems little
doubt, therefore, that these beds with S. catenata (Waehneroceras),
should be assigned to the planorbis zone; the sudden dominance of
Waehneroceras in the Barrow-on-Soar district is merely a local
characteristic comparable with the relatively early appearance of
P. planorbis in that neighbourhood. Thus the general section at
Barrow is as follows :—

ft. in.
Blue shale 6 0
angles | Impersistent limestone with 8. angulata 3
ane Blue shale with S. angulata . 0
Dark-blue pyritic shale, with great abundance of Waeh-
neroceras spp. and C. Johnstont. & 10 0
Roof Bed. Yellow earthy limestone with P. planorbis,
Planor bis C. Johnstoni, and Lima . 5 : aay eatolag@
zone. Hard blue shales with impersistent flaggy limestone : 4 0
' | Blue shales and pale-blue limestones with P. planorbis,
insect remains, andalge . : So eel La)
HKarthy limestone and brown shales, unfossiliferous : 4 0

-It is apparent that the fossil succession is very different from that
which. has been observed elsewhere, both in this area and in many
other parts of the country.

A third type of transition from Rheetic to Lias is seen in a small
stone quarry near Cotgrave Gorse, one and a half miles east-north-
’ east of the section described at Owthorpe. The uppermost bed of

1 The forms known as Schlotheimia catenata, d’Orb., should be referred to
several species of the genus Waehneroceras. See Table of Fossils.

2 T. Wright, ““ Monographs of Lias Ammonites’’: Palwont. Soc., pl. xix,
figs. 5-7.

3 A. Hyatt, ‘‘Genesis of the Arietide’’: Smiths. Contrib. Knowl., 1889,
Tables.

: A, E. Trweman—The Lias of South Lincolnshire.

HYDRAULIC LIMESTONE FOSSILS.

69

[a = Lower Planorbis zone (‘‘ pre-planorbis’’ beds), b = Upper Planorbis zone,
ce = Angulatus zone. |

Barrow-
on-Soar-

Normanton

Hills.

Owthorpe.

Cotgrave
Gorse.

Barnstone.

!

Coddington.

Saurian remains ;

Fish teeth and seales .
Psiloceras planorbis, Sow. .
Caloceras Johnstoni, Sow. .
C. ef. Belcheri, Simps. :
Waehneroceras frigga, Wah.
W. exechoptychum, Wah. .
Schlotheimia angulata, Sch.
Belemnites cf. acutus, Mill.
Turbo spp.

Avicula cygnipes, Y. &B.

Lima (Plagiostoma) gigantea,

Sow.
L. hettangiensis, Terq.
I. pectinoides, Sow. .
Monotis cf. fallax, Pfliicke .
Modiola minima, Sow.
Ostrea liassica, Strick].
O. sp
Pocton pollue, a ‘Orb. .
P. Thiollieri, Mart.
Pina sp.
Plewromya cr divcombeia,
Moore 2
P. sp.
Cidaris Edwar dsi, Wright .
Pentacrinus psilonoti, Qu.
Holothurian spines
(2? Cucwmaria) ‘
H. plates (? Synapta) .
Worm bores
Cytheridea ellipsoidea, Jones
C. cf. Moorei, Jones .
Dentalina pauperata, dv’ Orb.
D. tecta, Terq.
Fr ondiculari 1a nodosari 1,
pRerqe) i".
F. Terqueni, a’ Orb.
Involutina liassica, Jones .
Lagena elongata, Ehrenb. .
J.. cf. ovata, Terq.
Marginulina Romeri, Reuss.
Nodosaria raphanistr um,
Linn.
N. raphanus, Linn.
N. radicula, Linn.
Algee, Fucoid
Wood fragments.

a D

2a

ab

Bs 10)
a
b
b

b
a

-ab
a b
b
be

b

Bb io)

70 A. EB. Trueman—The Lias of South Lincolnshire.

the Rhetic in this quarry is similar to the one which has been
described in the South of England as the ‘‘Sun Bed”.’ The section
was given briefly by the Survey,” but more fully it is as follows:— _

ft. in.
Blue shales with Echinoid spines ; s : 2 0
EKarthy limestone with Ostrea, Modiola, and Lima 9 Te 2
Hard blue limestone with Modiola : : ; 5
Laminated blue shale . : : : 5 Siete: ; i 3
Sun Bed. Purple limestone : : : : : ig

As shown in Fig. 2, the lowest beds of the Loge Lias, which are
well developed at Owthorpe, a mile and a half away, are only
thinly represented at Cotgrave Gorse. ‘This, together with the
irregular appearance of the surface of the Sun Bed, suggests that
a short break in deposition may have occurred in this locality. The
occurrence of the Sun Bed at the top of the Rhetic on Beacon Hill,
Newark,’ about half a mile west of the Coddington trench sections,
is also interesting, but the section is now overgrown and it is
impossible to compare the succeeding deposits.

Owthorbe. Cotgrave Gorse.

Pleuramya Beds Ostrea Beds

Modiola Beds

sHAERT IC

Fic. 2.—Hydraulic Limestones of Owthorpe and Cotgrave Gorse ;
the lower beds thinning north-westwards.

2. Lower Lras Crays.

Apart from their use in brickmaking, these clays have little
economic value, and exposures in this area are rare. It is therefore
only possible to give an account of scattered observations, the
preservation of which may eventually facilitate a more complete
study of the district. Deep borings have shown the thickness of

1 A. KH. Trueman, op. cit., 1915, p. 152.
* Geology of Melton Mowbray (Mem. Geol. Sury.), 1909, p. 19.
* Geology of South-West Lincolnshire (Mem. Geol. Surv.), 1885, p. 21.

A. E. Prueman—The Lias of South Lincolnshire. 71

these clays to be about 700 feet, but yielded insufficient fosetl
evidence to determine the thickness of the zones.

Bottesford.—Brickyard 400 yards north-east of the church.

Although the brickearth used here is of alluvial origin, Professor
Swinnerton in 1915 found in a small exposure at the eastern end of
the yard a limestone with Coroniceras Bucklandi, which had not
previously been found in this area, although it had been recorded in
North Lincolnshire. In 1916 the section was as follows :—

ft. in.
Grey earthy limestone, yellow outside, with C. Bucklandi . 6
Blue clay . d : ‘ j : ; iL) (3
Yellow-grey earthy limestone 5 b ‘ i i 4
Blue clay . é : ; ‘ : : : 1 0
Blue earthy limestone | i : , : é 5 4
Clay . : : ‘ , : é : ! d c 2 0

Fossuls.

Fish teeth. Pecten sp.
Coromiceras Bucklandi, Sow. Pleuromya sp.
Gryphea (?) arcuata, Lam. Echinoid spines.
Hippopodium ponderosum, Sow. Pentacrinus et. scalaris, Goldf.
Lima gigantea, Sow. Cytheridea spp.
Modiola sp. Glandulina paucicosta, Roem.
Ostrea liassica, Str. Marginulina picta, Terq.

An interesting feature of the fauna is the presence of numerous
ostreaform Lamellibranchs, varying in development from the pro-
dissoconch to adult stages.

Sedgebrook.—Brickyard 400 yards north of Sedgebrook Station.

The exposure shows the following : —

Feet.
Soil; ete. . : i 2
Blue clay, w eathering yellow, with impersistent ferruginous
limestones and shell beds . d é 5 : : : 6
Fossils.

Armnioceras cf. semicostatum, Y. & B. Nucula aff. palme, Sow.
A. cf. ceras, Agass. Ostrea goldfussi, Bronn.
Belemmtes acutus, Mill. O. sp.
B. cf. breviformis, Voltz. Pecten cf. equalis, Qu.
Amberieya elegans, Miinst. P. calvus, Gold.
Trochus Redcarensis, Tate. P. lunularis, Roem.
GUS S50, P. ef. priscws, Sch.
Turbo sp. P. textorius, Sch.
Arca sp. Pholadomya aft. glabra, Agass.
Arcomya hispida, T. & B. Pinna Hartmanni, Ziet.
Astarte aff. striato-sulcata, Roem. Serpula sp.
Gryphea obliqua, Sow. Rhynchonella calcicosta, Qu.
G. arcuata, Lam. Kchinoid spines.
G. arcuata (a wide variety). Cytheridea ellipsoidea, Jones.
G. cf. cymbrum, Lam. C. Moorei, Jones.
Hippopodvum ferrz, Cross-Ether. C. aff. elongata, Blake.
Lima (Plagiostoma) gigantea, Sow. Dentalina cf. funiculosa, Terq.
I. (P.) punctata, Sow. D. (2) pauperata, d’Orb.
LL. (P.) aff. succincta, Sch. Frondicularia Terquemi, d’Orb.
Tnmea acuticosta, Miinst. Lingulina tenera, Borne.
Macromya sp. Margmulina picta, Terq.
Modiola bifasciata, Tate. Vaginulina anomala, Blake.

1 Water-supply of Lincolnshire (Mem. Geol. Sury.), 1904, pp. 63, 101.
2 By F. M. Burton; see Geology of Lincoln (Mem. Geol. Surv.), 1888, p. 19.

72 A. BE. Trueman—The Laas of South Lincolnshire.

The zone is evidently that of Pentacrinus tuberculatus, and the
horizon near that of the Plungar ironstone. The fauna resembles
that recorded by the Rev, J. E. Cross in the ironstones of the ‘‘ semz-
costatus zone”’ (tuberculatus zone of Oppel) at Scunthorpe, in North
Lincolnshire.’ It is interesting to note the absence at Sedgebrook of
all species of Cardinia, one of the commonest and most characteristic
fossils in the north of the county. Cardinia does occur, however,
within a few miles of Sedgebrook, near Bottesford and Allington, Z
and this suggests that the horizon seen here is not precisely that of
the Scunthorpe ironstone.

The strata between the two horizons just described were penetrated
in 1916 by an unsuccessful boring for water, which was made at
Plungar, about a quarter of a mile south- west of the church. The
section was roughly as follows :—

Feet.
Tronstone and clay with Gryphea, Lima, and Avicula about 4
Dark-grey marl 5 y , : : : Se we
Dark shale with shelly bands . : ‘ i : : Sipe 4)
Light-blue shale : : etd (D)
Several beds of fine blue limestone with C. Bucklandi : : 2
Blue shale : ‘ : : 6

It is probable that with tie oie of ie uppenmene few feet,
all the rocks passed through belong to the Bucklandi zone, which
apparently has a thickness of more than a hundred feet.

Higher beds were shown by another boring a few yards east of the
Stathern Station; it was made in 1916 by Messrs. Le Grand and
Sutcliffe, who gave permission to examine the core and supplied
some of the following particulars :—

od
cs
=

bo ag rt Ctr TT

Blue-grey clay. :

Shell beds and shales. Har thy limestone with Ostrea

Soft dark clay . : c é

Light-grey clay with thin limestone

Light-blue, hard limestone ; Ostrea

Light-blue marl] . : :

Massive limestone

Black pyritic marl

rey sandy marl with iramalhioranenen

*Grey marl with bands of earthy neeronel Sith Ostr, ed,
Pecten, Avicula inequivalvis : ;

Clay with bands of limestone

(Boring abandoned; no water reached. )

for)

bo

iso)

i
SS Samsecoooos

i)
forgive)

The bed indicated * contains an association of fossils which
resemble those in the ironstone band at Plungar, and is probably its
equivalent. The outcrop of the ironstone can only be traced for
two and a half miles south-west of Plungar,’ and it appears to have
a similarly restricted extension towards the south-east, for no
indication of it is shown in the boring, the strata passed through
consisting almost entirely of clays and shales.

' J. E. Cross, ‘‘ Geology of North-West Lincolnshire ’’: Q.J.G.S., vol. xxxi,
p. 123, 1875.

2 Geology of South-West Lincolnshire (Mem. Geol. Surv.), 1885, p. 30.

3 W. Gibson, Geology of Melton Mowbray, etc. (Mem. Geol. Surv.), 1909,
108 G35

J. W. Jackson—The Brachiopod Liothyrella. 73

_ Exposures of the clays above the Plungar ironstone are rare, and
such as still exist are not very helpful. <A brick-pit south of Brant
Broughton shows 10feet of fine-textured sandy clay, with fossils
indicating the oxynotum zone; another pit near the canal at. Wools-
thorpe shows similar clays which were thought by the Survey? to
represent part of the Jameson zone. A disused brick-pit south-east
of Bassingham in 1916 showed the following succession :—

ft. in.

ys “Marly clay with Pleuromya ; 4 ; 1
Yellow raggy limestone with Belemnites . : : : é i. @
Clay . é 6 : 6 0

Such fossils as were Pond lonaened the Sanvey? s conclusion that
these beds should be assigned to the armatum zone.’

(To be concluded in the March Number.)

IV.—On rox New Bracuiorop Genus, Lioruyretia, or. Tuomson,
By J. WILFRID JACKSON, F.G.S., Assistant Keeper, Manchester Museum.

HE new genus, Liothyrella, has recently been created by
Dr. J. Allan Thomson?* for the reception of a series of recent
and fossil Terebratulids commonly ascribed to the genus Liothyrina.
The chief characters upon which the genus is founded are the
presence of fine radial ribbing on the surface of the shells and the
possession of a short, low, thin, mesial septum in the dorsal valve.
In the thickness of the shell, Ziothyrella is said to stand between
LInothyrina (genotype L. vitrea) and Terebratula, sensu str., all three
genera being finely punctate. Thomson takes the recent Magellanic
species L. wea (Brod.) as the genotype of Lzothyrella, and includes in
the same genus L. uva, var. notorcadensis, Jackson,‘ from Scotia Bay,
South Orkneys, and a new species dredged off Tasmania by the
Mawson Expedition, as well as two Australian Tertiary ‘species,
Terebratula tateana, Tenison-Woods, and 7. concentrica (Hutton).
He remarks that ‘‘ probably also many of the other southern
species ascribed to JLvothyrina will be included here, but the
descriptions do not state whether or not a mesial septum is present”
(op. eit... p. 44).

The excellent researches made recently by Thomson upon the
morphology and classification of the Brachiopoda are to be highly
commended, as they have led to some remarkable discoveries being
made in connexion with New Zealand Tertiary species. Though
agreeing in the main with his conclusions regarding some of the
groups with which he has recently dealt, I feel compelled to dissent
from him with regard to the proposed division of the ZLzothyrine on
the lines defined. My own researches, extending over several years
and embracing numerous recent and fossil species, have led me to
offer the following observations.

1 A. J. Jukes-Browne, Geology of South-West Lincolnshire (Mem. Geol.
Surv.), 1885, p. 32.

2 W. H. Dalton, Geology of Lincoln (Mem. Geol. Surv.), 1888, p. 21.

3 Trans. N. Zeal. Inst., vol. xlviii (1915), p. 44, 1916.

4 Jackson, ‘‘The Brachiopoda of the Scottish National Antarctic Expedition ”’
Trans. Roy. Soc. Edin., vol. xlviii, pt. ii (No. 19), p. 375, pl. i, figs. 1-3, 1912.

74 J. W. Jackson—The Brachiopod Liothyrella. |

With regard to the mesial dorsal septum, though this appears to
be occasionally absent in the genotype of Liothyrina, viz. L. vitrea,
it is present in two of my specimens from the Mediterranean as |
a slight, but distinct, ridge between the muscle scars. One shell is
of large size with a thick test, but otherwise agrees with normal
L. vitrea. Fine radial strie are present on all my specimens. The
radial strize of Z. vitrea was noted by Fischer and Oehlert in 1891,'
as well as the thickening of the test and the presence of a mesial
septum in thick shells. JZ. vitrea thus possesses the three essential
characters upon which the new genus Liothyrella is founded.

Liothyrina cubensis (Pourt.), another northern species, often
regarded as merely a form of Liothyrina sphenordea (Phil.), supplies
us with contributory evidence. In one of my specimens from the
coast of Mexico, which agrees exactly with Davidson’s? and
Blochmann’s® figures, the radial striz are present, but are very
indistinct; there is also a slight thread-like ridge between the
muscle scars in the dorsal valve. In two specimens of the same
species from Porto Rico (100 fathoms) the radial strie and slight
mesial septum are also present, the latter showing through the shell.

In 1908 Blochmann (op. cit., pp. 612-25) divided the genus
Liothyrina in two groups according to the presence or absence of
certain calcareous spicules at the base of the cirri (Cirrensockeln).
The first group, that in which the spicules are present, is widely
distributed, and includes LZ. affinis, Calc. (Mediterranean, Azores,
ete., and possibly West Indies), Z. arctica, Friele (Iceland and
Greenland), Z. antarctica, Blochmann (Antarctica), Z. wuinteri,
Blochmann (St. Paul, Indian Ocean), Z. uva, Brod. (Magellanic
region and Western American coast to Mexico). With these he
provisionally included JZ. davidsoni, Adams, Z. elarkeana, Dall,
L. fulva, Blochmann, and ZL. moseleyz, Davidson. The second group,
without the basal spicules, comprises ZL. vitrea (Born), L. sphenordea,
Philippi, Z. cubensis, Pourt., Z. bartletti, Dall, and L. stearnsz,
Dall & Pilsbry. This group occurs chiefly in the Mediterranean
Sea and Atlantic Ocean, but one species (LZ. stearns?) is found off the
east coast of Japan. Another species (Z. cernica, Crosse), found at
Mauritius, is also referred to this group, though neither spicule nor
brachidium are known. The figures of Z. bartlett: and L. stearnsi
given by Blochmann (op. cit., pl. xxxix, figs. 27, 29) distinctly show
that each possesses a dorsal mesial septum.

Since Blochmann made this division other forms have been
described, viz. Z. uva, var. notorcadensis, Jackson (South Orkneys,
South Georgia, and Western Antarctic), and ZL. blochmanni, Jackson
(Antarctica). The former appears to belong to the first group, the
latter -to the second group. Further examples of Z. fulva, from

1 Haped. Scient. du ‘‘ Travailleur et du Talisman, 1880-3’’: Brachiopodes,
Paris, 1891, pp. 51, 57.
2 “A Monograph of Recent Brachiopoda,’’ pt. i: Trans. Linn. Soc., ser. 1,
Zool., vol. iv, pt. i, pl. ii, figs. 19-196, 1886.

> “Zur Systematik und geographischen Verbreitung der Brachiopoden”’ :
Zeit. fiir wissen. Zool., Bd. xe, pl. xxxviii, figs. 21-21c, 1908.

+ Jackson, op. cit., pp. 375, 378.

J. W. Juckson—The Brachiopod Lnothyrella. i

‘Tasmanian waters, show that it is now to be relegated to the second
sroup, as this species has no cirri bases.’ I had independently
arrived at a similar conclusion from the construction of its loop and
hinge-processes, details of which are given on a later page.

Of the first group I have only been able to study actual specimens
of Z. uva and its var., and ZL. antarctica, as well as some recent and
fossil specimens of Z. affints—the recent from off the Algerian coast,
the fossil from the Pliocene of South Italy and Sicily.

L. uva and L. antaretica have extremely fine radiating striz on the
surface of the shells, and both possess a slight mesial dorsal septum ;
this is at times somewhat more noticeable than in JL. vitrea and
LI. cubensis, though not to any great degree. L. uva, var. notorca-
densis, and ZL. blochmanni show similar features (see Jackson, op.
cit., 1912).

On ZL. affinis from Algeria the radii are clearly present and
wide apart; there is also a fine mesial septum in the umbonal
cavity of the dorsal valve; the shells are rounded in outline. Of the
fossil examples, two forms are present—elongate-oval (= typical
affinis) and rounded (ef. arctica)\—from the two localities, viz. Calabria,
S. Italy, and Messina, Sicily. These two forms are too near each
other to warrant separate distinction. The radial strize on both forms
are very indistinct, but they can sometimes be made clearer by
slightly moistening the surface of the valves. In type of cardinalia
they agree with the Algerian ZL. affinis, but the presence of a mesial
septum is a little uncertain.

The presence or absence of radial striation on Terebratulids should
form an interesting study. The following area few of the occurrences
which have come under my notice. Of Jurassic Terebratule,
T. phillipsi, from the Inferior Oolite of Broadwindsor, has incipient
radii, especially on the anterior portions of the valves. On 7. inter-
media, from the Cornbrash of Kidlington, the radii are likewise
present on the anterior and lateral portions of the shell. Among
Cretaceous forms, radial striation is fairly strong and wavy all over
the shell in 7. sella from the Lower Greensand of Hythe and
Wellingborough. TZ. depressa, var. cyrta, from the Lower Greensand
of Upware, also shows striz radiating from the beak: the dorsal
valve of this form has a mesial septum. On several of the Chalk
species presumed to belong to Liothyrina, e.g. T. carnea, T. semi-
globosa, etc., the striz can also be detected. They are fairly wide
apart and appear to be just below the outer layer of the test: they
are very indistinct and can only be seen on holding the shell in
a particular position. My observations have been made on 7’. carnea
from Grayesend, Norwich, Caburn, and Maestricht, and on 7. semz-
globosa from Lewes and other localities. 7. carnea possesses a distinct
mesial dorsal septum. A specimen of Z. obesa, from ‘Chalk,
Sussex (?)”, in my collection, is also radially ribbed, especially on
the flanks. The radii extend from near the beak to the anterior
border, and are closer together and more distinct than in 7. carnea,

1 Blochmann, ‘‘Some Australian Brachiopods’’: Papers and Proc. Roy, Soc.
Tasm. for 1913 (1914), pp. 112, ete.

76 J. W. Jackson—The Brachiopod Liothyrella.

ete. This feature is clearly shown in Davidson’s figures,’ and is —
referred to in the text (p. 54). It resembles that seen on recent
Dyscolie, especially D. crosset, Dav.

Among the Tertiary species, 7. bisinuata, from the London Clay,
is a good example. On my specimens from near Fareham the
radii are fairly wide apart and more noticeable on the side areas.
The dorsal valves show a thin, low, thread-like mesial septum,
superposed on a flat platform separating large pear-shaped muscular
impressions. In type of cardinalia this species is similar to the
well-known Crag Zerebratule, which also show the striation very
distinctly, especially on the lateral parts of the valves. These,
however, have no mesial dorsal septum. They are presumed to be
true TZerebratule. The cardinalia of these Crag forms and of
T. bisinuata, of the London Clay, have never been properly described.
The type is a peculiar one: there is a prominent semicireular, or
semi-ovate, cardinal process standing out from the apex of the valve
like a shelf; the socket-ridges, bounding the dental sockets, are
prominent and diverge from the apex, or at least from the corners of
the cardinal process; their inner sides descend sharply and touch
the floor of the valve posteriorly ; the plates then curve upwards
(ventrally) to the well-marked crural bases, the posterior extremities
of which are often clearly separated from the apex by a small space.
On the inner sides of the strong ridges forming the crural bases,
thin, narrow, plates are given off, these plates being free from
contact with the valve posteriorly and well separated from each
other mesially.?. In some of the dwarf Crag Terebratule these inner
hinge-plates are much broader and touch each other in the median
line at their posterior ends. While dealing with the Crag Zere-
bratule it may be of interest to refer to an allied form occurring in
the Pliocene of Calabria, 8. Italy. This form, usually recorded as
T. grandis or T. scille, has a type of cardinalia similar to the Crag
form, except that the inner hinge-plates are very rudimentary. Of
the five examples cleaned out “and examined (these being of equal
size to the Crag examples dealt with), all exhibit the same features ;
but in one or two there is a thread-like mesial septum.

The above-mentioned ridges (crural bases) with their attached
inner hinge-plates clearly distinguish this type of cardinalia from
that of Liothyrina. No evidence of these inner plates is present in
any recent Liothyrine ; nor are the crural bases so well defined.

The aseription of the Chalk species to the genus Lvothyrina
(mainly, I believe, on account of the grooves for the attachment of
the pallial sinuses showing through the test) is open to some
question. Their general external appearance, small foramen, and
the massiveness of the cardinalia suggest that they might be
terminal members of a distinct genetic group. The following
remarks are based mainly on a study of several valves of 7. carnea
which have been developed to show interior details. The most

1 Monog. Brit. Cret. Brach. (Pal. Soc.), 1854, pl. v, figs. 13-16.
2 For a good figure of the cardinalia, see Davidson, Monog. Brit. Tert. Brach.
(Pal. Soc.), 1852, planusnhews.

J. W. Jackson—The Brachiopod Liothyrella, - TT

notable feature of this species is the excessive thickening of the
hinge-processes and muscular fulcra generally. ‘This fact renders
it a somewhat difficult matter to define the type of cardinalia.
I fortunately possess one specimen in which the calcification has
not progressed so far as usual: this shows both cardinala and
brachidium. The crural bases in this are well-defined and consist
of fairly broad plates set almost vertically to the slight hinge-
plates uniting them with the high-standing socket-ridges. The
hinge-plates unite along the middle line of the crural bases, the
latter having a well-defined ventral and dorsal edge. I have seen
no junction like this in any recent Lrothyrina; nor is it present in
the Crag or London Clay TZerebratule. There is a prominent
cardinal process at the apex of the valve; also a thin hair-like
mesial septum in the umbonal cavity. Both the cardinal process
and mesial septum become more definite in the thickened specimens.
The crura are broad and short; the descending branches and trans-
verse band of the loop are also broad, and the latter is sharply bent
ventralwardsin the middle. he junction of the descending branches
with the transverse band issharply angulated. Figures of the interior
of 7. carnea are given by both Davidson ' and Quenstedt.?

Before proceeding it might here be appropriate to point out that
the brachidium of the Crag Zerebratule differs from that of 7. carnea
in being relatively wider with a narrow transverse band not sharply
bent ventrally, and in having much sharper points at the extremities
of the descending branches. It has also longer crural points.* In
general characters it resembles that of the recent Z. wva, but not
that of LZ. vitrea.*

The cardinalia and brachidium in recent Liothyrine exhibit some
interesting features. The type seen in Z. wa and closely allied
forms differs somewhat from that of the genotype, L. vitrea, and
very materially from that of Z. stearnsi or L. bartletti. The extremes
are clearly seen in Blochmann’s figures (op. cit., 1908, pl. xxxix).
In LZ. ua the whole structure is of a short triangular form, and the
transverse band of the loop is very narrow. The junction of the
descending branches with the transverse band is sharply pointed.
The crural points are close in. - Between the socket-ridges and the
ill-defined crural bases is a narrow curved plate. There is a thin
mesial septum. In JZ. stearnst, on the other hand, the structure
consists of long, almost parallel, descending processes, and the
transverse band is very broad; it is alsosharply bent ventralwards
in the middle. The characteristics of Z. stearnsi are taken from
Blochmann’s figure (op. cit., 1908, pl. xxxix, fig. 29). ZL. vitrea
and some others appear to agree closely with this form. In general
the crural bases, which are not very marked, are well separated

1 Monog. Brit. Cret. Brach. (Pal. Soc.), 1854, pl. viii, figs. 2, 2a.
b 2 Petrefactenkunde Deutsch., II, Brachiopoden, Leipzig, 1871, pl. xlviii,

g. 42.

* This is based upon the figure given by Davidson, Suppl. Tert. Brach.
(Pal. Soc.), 1874, pl. ii, fig 1, and upon imperfect specimens of my own.

* The ovate outline and broad dorsal uniplication of the Crag shells also
show greater affinity with LZ. wva.

78 J. W. Juckson—The Brachiopod Liothyrella.

from the socket-ridges by flat, or slightly concave, thin plates.! As
stated previously, a thin mesial septum is present in some of these
forms. ; ;

These two types appear to characterize two distinct groups of
species, the members of which possess certain common features.
The first group comprises broadly dorsally uniplicate oval shells
with a rounded front, as, for example, Z. wa, and var. notorcadensis
and ZL. antarctica, a group which, according to Blochmann, possesses
basal spicules in the cirri; while the second group comprises shells
with a somewhat truncated front, and, in some cases, broad dorsal
uniplication, such as L. witrea, L. sphenoidea, L. cubensis, L. bartletii,
and Z. stearnst—a group without the basal spicules. The shells of
this group are, as a rule, much larger than those of the first group.

By adopting the principle of classification by means of the
construction of the brachidium and cardinalia I had already arrived
at the conclusion that two such groups existed. It is interesting,
therefore, to find that this is borne out with regard to spiculation.
We have thus a standard which is of some service in the classification
of fossil forms, the question of spiculation being, of course, im-
practicable for fossils. It was on these grounds that I placed
ZL. fulva, which has a broad transverse indented band to its loop,? in
the second, or LZ. vitrea, group. This hasnow happily been confirmed
by Blochmann’s researches with regard to spiculation. From his
figures (op. cit., 1914, pl. x, figs. 1-4) this species appears to be
non-plicate with a tendency towards a truncated front.

Other species of recent Lrothyrine still await further examination.
L. moseleyt, apparently a lenticular species, has a broad indented
transverse band to its loop.* Its spiculation is, as yet, unknown,
but from the circumstance that a broad band appears to go with
weak spiculation, it is not unreasonable to assume that it will be
found to be of the Z. vitrea type. The interior details of Z. david-
sont and L. clarkeana are too scanty for diagnostic purposes. The
Antarctic Z. blochmanni has a type of cardinalia and brachidium
quite distinct from that of Z. uva or L. antarctica, it being nearer
that of ZL. sphenoidea.t Its spiculation appears to be of a weak
character, and, therefore, more like that of the Z. vitrea series, with
which I have placed it.

From the above observations it has been seen that the presence or
absence of radial striation, or of a mesial dorsal septum, does not
assist materially in the separation of Terebratulids into generic
groups. On the other hand, the character of the brachidium and
especially the cardinalia, which owing to their role as supports for
important elements of the muscular system, and consequently

' See Blochmann, op. cit., 1908, pl. xxxix; also Fischer & Oehlert, op. cit.,
1891, pl. iii (for LZ. vitrea and L. sphenoidea).

2 See Blochmann, op. cit., 1908, pl. xxxix, fig. 26; and Blochmann, op. cit.,
1914, pl. x, figs. 5, 6.

3 See Blochmann, Wissen. Hrgeb. der Schwed. S.-P. Exped., 1901-3,
Bd. vi, Lief. vii, pl. i, fig. 14, 1912.

* Compare Jackson, op. cit., 1912, pl. i, fig. 6, with Blochmann, op. cit.,
1908, pl. xxxix, fig. 23a.

J.B. Scrivenor—Kaolin Veins, Federated Malay States. 79

subject to more modification, may provide more certain ground for
distinguishing the various groups of related species.

On these grounds it has been clearly proved that the Chalk species
(7. carnea, etc.) are not to be referred to Lvothyrina, but probably
belong to a separate group entirely; and that the Crag and other
Tertiary Zerebratule form another distinct series. If we accept the
evidence as trustworthy in these cases, we seem compelled to
acknowledge the new genus Liothyrella, recently created by Thomson,
subject to the emendations dealt with in this paper.

V.—Tase Kaorrn Verns.
By Lieutenant J. B. SCRIVENOR, M.A., F.G.S.
AOLIN occurs abundantly in the Federated Malay States in

connexion with granite, and is certainly formed on a large
scale by weathering. The purest kaolin in large quantity, however,
is found as veins in clay above limestone at Gopeng aid elsewhere in
Kinta, and in quartzite and shales near Tanjong Malim and Kerling.
The purity of these veins and the information obtained about those
in Kinta when traced down to limestone, lead to interesting
considerations about their origin, and the nature of the material in
the limestone is a matter of importance in connexion with the
possibility of establishing a kaolin industry.

The form of the Gopeng veins has been described elsewhere, and
in the early edition of the Kinta publication, illustrations were given
showing the junction of the kaolin and clay. In A Handbook to the
Collection of Kaolin, China-clay, and China-stone in the Museum of
Practical Geology, 1914, by Mr. J. A. Howe, some notes were
contributed and a vein at Kramat Pulai figured (p. 102). In these
notes I stated, “‘ No fresh felspar or partially decomposed felspar has
been detected as yet in these veins. This might be taken as evidence
of the kaolin having been kaolin ad origine and not an alteration
product, but it is not conclusive evidence against a pneumatolytic
origin.”’ Since writing this, residues from many samples of kaolins
treated with acid have been examined, and among them some from
the Gopeng veins. The minerals unattacked are mica, quartz,
tourmaline, and small grains, not abundant, that may be partially
decomposed felspar. From kaolin near Kerling (Selangor) sand
lighter than 2°8 sp.g. was separated, and in it are a few grains that
may be partially decomposed felspar. In the field I have not seen
any felspar in these veins, but in places where quartz is abundant
I have noticed a trace of graphic structure, as though quartz and
felspar had once been intergrown.

A pink mica is present in these veins and has been described as
lepidolite. A specimen of similar mica from Chanderiang gave
a strong lithia reaction with the spectroscope, but one specimen from
Gopeng proves on analysis by Mr. C. Salter, to be muscovite with
°86 per cent of manganese. It is possible, therefore, that much
of the pink mica may be a manganese mica.

Tin-ore is believed to occur in the Gopeng veins, and is known
to occur in the Kerling veins, in fact they are worked for tin.

80 J. B. Scrivenor—Kaolin Veins, Federated Malay States.

Kaolin from the Kerling veins was washed and afforded deep brown
cassiterite and mica. No toarmaline was found. in the concentrate,
nor was it seen in the field.

Lately information has been obtained at Gopeng and Pulai about
these veins in contact with the limestone. At Kramat Pulai
a pinnacle of limestone was exposed in January, 1916, close to
a kaolin vein. In the limestone was a granitic vein about 2 feet
wide, bordered by a pale-green massive mineral with a slightly
greasy feel. The granitic rock contains felspar, sometimes in
porphyritic crystals. Sections show that it consists of quartz,
orthoclase, and plagioclase, the last being abundant. One specimen
is finely veined by a serpentinous mineral that is probably the pale-
green mineral just mentioned. They show a little tourmaline and
some altered biotite, and also micaceous aggregates suggesting
pinite pseudomorphs of cordierite. Near by, in the same pinnacle,
are thin veins of ‘‘mountain-leather”’ or asbestos of the serpentine
variety (magnesium silicate), together with purple quartz. No vein
of kaolin was seen in the limestone.

On the Kinta Tin Mines, Ltd., large quantities of the pale-green
massive mineral occur in juxtaposition to limestone. It is not as
greasy to the touch as steatite, but resembles it, and partial analysis
showed that it consists of magnesium and aluminium silicate. It is
therefore one of the ill-defined minerals allied to serpentine, and
differs from the kaolin in having magnesium present in addition.

The same mineral occurs associated with kaolin in two of the
open-case mines on the Gopeng Consolidated land. In that on the
north of and close to the Khota Bahru Road there were found with it
fairly large crystals of a reddish mica which contained no lithium,
and one specimen was found consisting of this mica, quartz, and
andalusite. ‘The kaolin, close to where this specimen was taken,
contained dendritic markings of manganese oxide, and a small pocket
was found in the kaolin of black clay consisting of manganese and
iron oxides. Its presence was puzzling until it was discovered that
some at least of the. pink mica at Gopeng is a manganese mica.

In a big mine south of the Khota Bahru Road there was a good
section in March, 1916, of the magnesium-aluminium silicate in the
limestone. It formed a distinct vein about 2 feet across. Close by
was kaolin with quartz and white mica. Near by here pockets
of the same mineral were found in pure white kaolin. —

In the above instances there is no evidence of the kaolin
continuing in the limestone as kaolin. It changes to something
else, and the green magnesium - aluminium silicate suggests a
reaction between the magma that supplied the kaolin and magnesium
in the limestone. The way in which the granitic vein on Kramat
Pulai is bordered and veined by this mineral favours this view.
On the North Tambun Mine, however, I have seen a very thin
kaolin vein in limestone, and many years ago I saw a similar
thing at Tambun. However, there is now strong evidence that the
bigger veins do not go down into the limestone as kaolin, and one
naturally wants to know how they were formed, and the first
explanation that presents itself is that they are veins that were

~

J.B. Scrivenor—Kaolin Veins, Federated Malay States. 81

originally chiefly felspar, which has been altered to kaolin’ by
deep-seated changes during the last stages of the cooling of the
granitic magma. If that is incorrect, then the kaolin must have
been kaolin from the moment it consolidated, or it must have been
formed in recent times by weathering. With regard to this question
of the origin of kaolin, there is a marked difference of opinion
between British and American geologists. It is difficult to get one
of the former who has not visited the Tropics to allow that kaolin
can be formed by weathering at all. On the other hand, Lindgren,
in his Jhneral Deposits, p. 305, writes as follows: ‘‘The idea
that the mineral may form by pneumatolysis, or the action of water
or gases liberated at high temperature from igneous magmas, is
assuredly untenable; a strongly hydrous mineral, parting with its
water at the comparatively low temperatures of 300 to 400°C., could
not possibly originate in the presence of such minerals as topaz and
tourmaline.”’ Lindgren favours an opinion that certain china-clay
deposits in Cornwall, generally regarded as of pneumatolytic origin,
were formed by the weathering of sericitic granite, the sericite being
due to previous alteration by thermal waters. It is not necessary,
however, to postulate that kaolin was formed at the same time as
topaz and tourmaline. It may have been formed afterwards when
the temperature was lower; and, as kaolin formed by weathering
from the granite in the Malay States contains much of recognizable
felspar, unattacked or only partially attacked, the purity of the
Gopeng and other kaolin veins might be cited as pointing to a
different mode of origin. The objections to its having been kaolin
from the beginning are the same as those brought forward by
Lindgren to pneumatolysis, and even stronger when applied to this
idea and more applicable. Moreover, there is some, although not
good, evidence of felspar being present in small quantities. On
the other hand, if the kaolin is due to pneumatolytie action, why
do the large veins stop when the limestone is reached? The
granitic vein on Kramat Pulai points to pneumatolysis, if it took
place at all, having been confined to rocks above the limestone,
and makes weathering seem less impossible as a mode of origin
than I once thought. It is to be hoped that future excavations
on the tin-mines will give some decisive information one way or
the other.

Specimens of kaolinite formed by weathering from felspar in
the Main Range granite at the Gap, Pahang, and specimens of
kaolinite from Gopeng and Kerling, have been compared with
kaolinite from a kaolinized felspar crystal in the Dartmoor granite.
The refractive index is about the same in all cases. The double
refraction is more marked in the Gap kaolin than in the others.
In the Gopeng specimen fan-shaped and vermicular aggregates of
plates are common. Vermicular aggregates also occur in the
Kerling specimen. The Gap kaolinite forms some aggregates of
parallel plates, and the kaolinite from the Dartmoor specimen
forms irregular flakes only.

At the same time specimens of ‘‘ Lenzinite” and ‘‘ Glagerite’’
allied hydrous silicates of alumina, were examined. The Lenzinite

DECADE VI.—VOL. V.—NO. II. 6

82 Notices of Memoirs—Martin Simpson.

had a lower refractive index than any of the above; the double
refraction was hardly noticeable and it consisted of very fine flakes
and minute vermicular aggregates. The Glagerite had a higher
refractive index than any of the other specimens.

The examination of these specimens was undertaken in the hope
of arriving at some definite conclusion about the origin of the kaolin
veins in this country, but it cannot be said that one has been
attained.

NOTICHS OF MEMOTRS.

I.—Marrtin Simpson, 4 YorKsHire GxEotoeisr (1800-92).
T the annual meeting of the Yorkshire Geological Society, held
at Leeds on December 12, Mr. T. Sheppard, M.Sc., F.G.S., read
a paper on “‘ Martin Simpson and his Work ’’.

Martin Simpson was born at Whitby in 1800, and died in 1892.
He spent most of his life in the Whitby district, and for over half
a century had charge of the valuable Geological Collection in the
Museum there, though for a short period he was Curator of the
Yorkshire Geological Society’s Collection, now in the Museum at
Leeds. He was one of the pioneer workers among the Yorkshire
Liassic rocks, and considering the early date of his researches the
enormous amount of information he accumulated was remarkable,
and his methods of research had a surprisingly modern air. He was
the author of a number of geological memoirs, most of which are now
exceedingly scarce.

Mr. Sheppard showed a complete series of these works, which he
had collected, the most important being a memoir on the Ammonites
of the Yorkshire Lias, which was long since said to be so rare that
only one copy was known. Another work, published when the
author was 84 years of age, was The Fossils of the Yorkshire Luas,
in which no fewer than 743 species were enumerated and more or
less described. Simpson measured with a foot-rule the thickness of
the Lias beds north and south of Whitby, taking special note of the
fossils in each bed, a very early example of zonal collecting.

IJ.—THe Minerat Resources oF THE British Empire.

NOR the second year in succession the Swiney lectures were
given by Dr. J. S. Flett, F.R.S. As already announced in

the GronoeicaL Magazine, the subject chosen was ‘‘The Mineral
Resources of the British Empire”. By means of a judicious
mixture of statistics, engineering, and geology Dr. Flett succeeded
in giving a remarkably interesting, though necessarily condensed,
account of a very large subject. It was shown that in the case
of some minerals, such as tin, nickel, and diamonds, the British
Empire is still the greatest producer, while in other instances its
former pre-eminence has passed into foreign hands, especially into
those of the United States and Germany. It is evident that in the
immediate future Canada will be an important producer of many
minerals, besides oil and gas on a large scale. The mines of Sudbury,
Cobalt, and Porcupine were dealt with by the lecturer in some

a
1 ae
2

Reviews—Life of James Geikie. — 83

detail, and a great future was predicted for the metal cobalt, which
in some ways is.superior to nickel. The production of tungsten ores
has been greatly stimulated by the War, and many new sources have
been discovered. Molybdenum is also rapidly increasing in im-
portance for the same reason. The gold production of South Africa
has now reached the enormous value of nearly forty million pounds
sterling per annum.

The lectures, which were illustrated by a large number of excellent
lantern slides, were listened to by large and appreciative audiences,
and must be regarded as highly successful.

Il1.—THe AcE or trun Bottvian ANDES.

N 1915 Professors Singewald and Benjamin L. Miller collected
from rocks of hitherto undetermined age in the copper district
of Corocoro fossil plants of the same flora as that previously known
from the silver district of Potosi, whence also they made collections.
These have been described by Professor E. W. Berry (Proc. U.S.
Nat. Mus., vol. liv, pp. 103-64, pls. xv—xviii, October, 1917) and
the types and figured specimens presented to the United States
National Museum. The age of the flora is determined as Pliocene,
whence it follows that the major elevation of the Eastern Andes
of Bolivia and the high plateau took place in the late Plocene and
throughout the Pleistocene, and that the extensive mineralization
of the region is of equally late geological age. A Brachiopod,
Discinisca singewaldi, found at 18,500 feet above sea-level, and
described by Professor Schuchert in the same. paper, similarly
proves an elevation of at least that amount since Miocene times.

TV.—Westr AvsrraLian CHatk ForaMINIFERA.

fJ\HE fauna of the Gingin Chalk (= Albian to Cenomanian) was

made known by the researches of Robert Etheridge, jun.
(Bull. Geol. Surv. W. Australia, No. 55, 1913), and its Foraminiferal
contents listed by Howchin (Rep. Adelaide Meeting Austr. Assoc.,
September, 1893). Since then Frederick Chapman has been working
on the deposit, and has now produced a monograph on the Foramini-
fera and Ostracoda (Bull., No. 72, 1917). A mere glance at
Chapman’s careful drawings shows the completely Upper Cretaceous
nature of the deposit and the remarkable agreement of the fauna
with the English equivalents. Kighty-one pages, of which 14 are
devoted to illustrations (plates); 134 species of Foraminifera, 16 of
Ostracoda.

REVIEWS.

I.—James Gerrxin, THE Man and THE Gerorocisr. By Marion
I. Newsiern and J. 8. Frerr. pp. xi + 227, with four portraits.
Edinburgh: Oliver & Boyd, 1917. Price 7s. 6d.

fJ\HIS charmingly written book is divided into two distinct parts.

The first, by Miss Newbigin, deals with James Geikie’s life
from the biographical standpoint, while in the second part Dr. Flett

Sao Reviews—Life of James Geikie.

gives an appreciation of his scientific work. The first part sketches —
in a somewhat brief but thoroughly interesting way the career of one
of the best-known British geologists of the second half of the
nineteenth century, a man who had a great influence on the trend of
geological thought in this country and who was mainly responsible
for building up a highly successful school of geology in the University
of Edinburgh. The authoress deals in a sympathetic way with
Professor Geikie’s private life, with his career on the Geological
Survey, and with the part he played in the scientific and social life of
‘Scotland in his time. Although primarily an investigator and field
geologist, Professor Geikie ultimately became a great teacher and his
books are known everywhere for their breadth of view, lucidity, and
charm of style. Perhaps, however, his success as a teacher and on
the Survey was still more owing to his personality and to his power
of communicating some of his own enthusiasm to his fellow-workers
and pupils.

As a geologist James Geikie was a specialist in two directions:
he was always deeply interested in the origin of physical and
structural features, and in his teaching and writings he endeavoured
to draw out the connexion between topography and geological
structure. But his name will always be indissolubly connected with
the study of glaciation. In the second part of this book Dr. Flett
has given us an admirable and impartial summary of his work on
this thorny subject. The glacial controversy has been a long one,
comprising several distinct phases; even now it seems almost as far
as ever from an end. The life of James Geikie may in a certain
sense be regarded as an impersonation of the history of glaciology.
When his work began the submergence theory was dominant, though
soon to be replaced by the land-ice conception. In this change of
view his own work played a great part. ‘he course of evolution in
this respect may be traced in the successive editions of his book,
The Great Ice Age. Some twenty years ago land-ice appeared to
hold almost undisputed possession of the field, although some notable
geological authorities have always questioned its applicability to
districts such as central and eastern England, far from any system of
mountains. However, of late years a certain number of awkward
facts have cropped up and the still small voice of doubt is again
making itself heard in the ears of some of the younger generation ;
at any rate, it is clear that the time has not yet arrived for a definite
decision, and it would be well to suspend judgment for a while. _

Another phase of the glacial controversy relates to the occurrence
of periods of milder climate between successive glaciations. It is
with this part of the subject that Professor Geikie was always most
closely connected. He will ever be remembered as the apostle of
interglacial periods. In his later writings he maintained a succession
of six separate glaciations with temperate periods between. In this
respect his views agree closely with those of many Continental and
American authorities, and, although he did not at the time receive
much support in this country, the trend of recent work has
undoubtedly been unfavourable to the hypothesis of a single advance
and retreat of the ice, which at one time was the orthodox view.

Panacuneitaeail Kehini, Panama. 85

This is impossible to reconcile with the results of the examination of
peat-mosses and Arctic plant-beds in many parts of the British Isles,
and still more with the brilliant discoveries of recent years in
regard to the stages of palewolithic culture and their relation to the
Pleistocene deposits. It is too early as yet to pronounce any decided
opinion on this subject, but, as Dr. Flett points out, there are signs
of a very decided reaction in this respect. If Professor Geikie went
too far in one direction, it is certain that his opponents went too far
in the other. The subject is a peculiarly difficult one, and it is
evident that long and patient investigation is still needed before
a final settlement can be reached. It will be conceded by all, what-
ever may be their personal predilections, that the life-work of James
Geikie played a leading part in the unravelling of this tangled skein,
and the authors of this book are to be congratulated on having given
a clear picture of a great man and a great geologist.
Ings dels des,

I1.—Fossin Eonrnt or tHE Panama Canat Zone and Costa Rica.
By Rosert Tracy Jacxson.. Proc. U.S. Nat. Mus,, vol. liu,
pp. 489-501, pls. ]x1i—lxviii.

ae short and lavishly illustrated paper provides an account of

the Echinoids collected from the Oligocene-Miocene rocks

excavated during the making of the Panama Canal. The fauna thus
displayed is of asomewhat restricted, but characteristically American,
type. No Regular Echinoids are recorded, and the species described
belong to four genera only of Irregular forms. ‘The two species of
Clypeaster (of which one, C. gatuni, is new) call for no special
comment. The three species of Hncope (2. annectans, E. platytata,
and #. megatrema, all new) exhibit features of exceptional interest,
to which reference will be made below. The solitary Hehinolampas
is a well-known West Indian form. Of the three species of Schizaster,
two (S. eristatus and S. panamensis) are new, but their preservation
is very imperfect.

The genus Hncope includes an extensive series of Scutelliform
Clypeastroids, characterized by marginal slits on the ambulacra, and
a solitary lunule perforating the posterior interambulacrum about
midway between the apex and the ambitus. This quality may be
considered as intermediate between that of Scuted/a, in which there
is no lunule and hardly any development of marginal slits, and that
of Melita, in which the interradial lunule is present, while the
marginal slits have become distally enclosed so as to produce
ambulacral lunules. The ontogeny of the latter genus shows that
the ambulacral lunules are developed from slits or notches around
which the test spreads in later growth-stages, but that the interradial
lunule is formed by resorption of the test, and is thus a real
perforation. (There is one species of Mellita in which all the lunules
have the latter character, but this is quite exceptional.)

In Encope annectans, described in the paper under review, the
marginal (ambulacral) slits are in the stage of embayment normal for
species from the horizon (? Burdigalian), but there is no interradial

86 Beviews—Prof. Bonney— Volcanoes in Many Lands.

lunule, properly speaking. Instead, there are two short, narrow
grooves indented into the test, one on the adapical surface and one
immediately below on the adoral surface by the periproct. The
appearance is as if the specimens were wax models which had been
pinched by a hot pair of fine forceps. ‘The lunule is thus in this
species ‘‘ caught in the act’ of developing by resorption. There is
no question of this being an ontogenetic stage of some more ordinary
species, for the type is 86mm. long, and another specimen 93 mm.
We have here a peculiarly perfect illustration of the interrelation
between phylogeny and ontogeny.

But Encope annectans must be a specially retarded or atavistic
species, for side by side with it, in the same district and at the same
horizon, lived #. megatrema, in which the interradial lunule is
gigantic when compared with that usual in the genus. The great
triangular perforation occupies a large part of what should have been
the posterior interambulacrum, comparable (when viewed from the
adapical surface) with the large periproct of such a genus as Prleus.
E. megatrema represents a high-water mark of lunule-specialization
that has not been attained since. Thus the period of the Gatun
formation in Central America marks the childhood of the Hncope-
. stock, and the two species here discussed represent respectively the
backward and precocious members of the family. Students of
phylogeny will welcome this reminder that it is particularly
characteristic of youth to run to extremes, and it is this faculty
which makes children so fascinating, be they of Holocene or

Oligocene date.
D8 Ge IGai ely

III.—Votcantc Srupres In Many Lanps (Seconp Sezrtrzs),’ being
Repropuctions oF PHoTOGRAPHS TAKEN BY THE AvurHoR. By
Tempest AnpErson, M.D., D.Sc., ete.; Text by Professor T. G.
BowneEy, Sec.D., F.R.S., ete. London: John Murray, 1917.
lds. net.

LL geologists who remember Dr. Tempest Anderson’s first book

of photographs of volcanic phenomena will welcome the
publication of a second series which has been undertaken by Professor
Bonney under the above title. The work entailed in collecting and
arranging the views here reproduced must have been considerable,
since many of them deal with little-known districts, and as some in
addition were taken on Dr. Anderson’s last journey, from which
unfortunately he never returned, the exact localities of many of

' The first part of Dr. Tempest Anderson’s Volcanic Studies in Many Lands
appeared in 1903, and was reviewed in the GEOLOGICAL MAGAZINE for that
year by Mr. Hudleston, pp. 160-4. Dr. Tempest Anderson, who spent
many years in visiting and photographing active and extinct volcanoes in
almost every part of the globe, died on his return voyage from the Philippine
Islands, August 26, 1913 (see Obituary, GEOL. MaG., Oct. 1913, pp. 478-9).
By his will he left £50,000 to the Yorkshire Philosophical Society, of which
he had always been a generous supporter; he also added £25,000 to the
Percy Sladen Memorial Fund, endowed by his sister in 1904 (see GEOL. MAG.,
Feb. 1914, .p. 96).

* Reviews—Prof. Bonney—Volcanoes in Many Lands. 87

them were rather doubtful owing to the fact that the notes which he
left were often very brief. However, Professor Bonney has done his
work well and has, from the material which he found, built up very
interesting accounts of some rather imperfectly known volcanic
regions.

The book is prefaced by a short life of the author by his friend
Mr. G. Yeld, and the chapters immediately following this deal with
European volcanoes, and illustrations are given of Vesuvius, Etna,
and Stromboli, the latter in eruption; one illustration shows a
curious oval-shaped detached smoke cloud floating away from the
summit of Etna. The following chapters deal with a second visit to
Martinique and St. Vincent, and photographs are reproduced of the
returning vegetation on these volcanoes, and also of the surface of
the ash deposits formed in the eruption of 1902, showing the effect
of denudation on the loose material. In 1906 Dr. Anderson visited
Mexico to attend a meeting of the International Geological Congress
and endeavoured to obtain photographs of the volcanoes of that
country. Owing to the difficulties of travel, not so much was
accomplished as was hoped, but photographs were obtained of some
of the principal peaks, the most striking being those of Iztaccihuatl
and Colima.

From here Dr. Anderson went on to Guatemala. The volcanoes
of this country form a row of cones averaging from 10,000 to
12,000 feet in height, roughly parallel with the Pacific coast. They
are situated along ‘the edge of a hilly platform about 5,000 feet high,
which rises abr uptly from the sea, so that, from a passing ship, they
may be seen to the full advantage. Their activity is rather inter-
mittent, but eruptions, when they do occur, are generally violent ;
the ejected material is chiefly fragmentary, lava being very rare.

The most important cones are Cerro Quemado, Atitlan, and Santa
Maria. The first, except for a small eruption in 1891, has been
quiet since 1785, when it discharged large quantities of lava which
must have been very viscous, as the flows often terminate with
vertical walls as much as 100 feet in height. Some very fine ‘‘ bread-
crust’’ bombs were seen here, one of which is shown in a photo-
graph. Atitlan, 11,570 feet high, is 35 miles south-east of Cerro
Quemado. Dr. Anderson ascended the mountain, but found on the
summit only a very ill-defined crater, with afew fumaroles. The
mountain looks down on to a lake twenty miles in length, which
from its shape seems to have been a volcanic crater. ‘he third
mountain, Santa Maria, which lies a few miles south of Cerro
Quemado, is a very regularly shaped ash cone. Prior to 1902 it was
supposed to be extinct, but in that year a great lateral outburst
occurred which shattered the northern slopes of the cone and
produced a new subsidiary crater on a small shelf 6,000 feet above
sea-level. The new crater was oval in shape, about three-quarters
of a mile long, with its major axis parallel to the Pacific coast.
Photographs are reproduced showing Atitlan and Santa Maria and
also a nearer view of the new crater on the latter mountain; the
distant view of Santa Maria is an exceptionally fine piece of work,
and shows the great rent in the side of the cone and the new crater.

88 Reviews—Prof. Bonney—Volcanoes in Many Lands. *

‘After several chapters dealing with Tarawera, Matavanu, and
Kilauea, the book goes on to consider Java, Krakatau, and Luzon.

In Java Dr. Anderson visited, among other peaks, Guntur,
Papandayang, Telaga Bodas, and the lenger crater, with its enclosed
cones of Batok, Bromo, and Widodaren. Guntur is a fine pyramidal
mass rising up out of quite level ground. It is now quiescent, and,
though a fine photograph of it was obtained from a distance, the
jungle with which it was covered made it impossible to photograph
the crater. Papandayang, which is quite close to Guntur, is also
at present quiescent, but in 1772 there occurred one of the most
destructive eruptions which have affected the island. It shows
from a distance the characteristic form of a fragmental cone, its
crater is large, but is now only occupied by fumaroles and hot
springs. From here Dr. Anderson went on to the other end of
the island, where he visited the Tenger crater and its accompanying
smaller cones. This region shows volcanic phenomena on a very
large scale. The Tenger crater, which is close to the town of
Tosari, is 6 miles long by 43 broad, and contains on its floor,
which is known as the Zandzee, three minor cones, Batok, Bromo,
and Widodaren. These all present the customary form of such
minor fragmental cones, and their sides are deeply furrowed by
small gullies cut out of the loose ash. Of these only Bromo is
still active. Some very excellent photographs were obtained of this
crater, one showing very well the smooth-sided depression lke
a ‘gigantic pudding mould’’ with the steaming vent at the bottom.
From Java Dr. Anderson went on to Krakatau, and from there to
Luzon in the Philippine Islands, where he visited the Taal lake and
voleano, and also sailed round the island, taking photographs of
several volcanoes on the way. One of these is Mayon, in the south-
east corner of Luzon; this, as seen from the sea, presents a very fine
example of an ash cone, being 8,970 feet high, quite symmetrical
and showing the concave volcanic curve to perfection. This voleano
was in eruption in 1814, and devastated the neighbouring country,
killing 12,000 of the natives. At the south-western corner of the
island is the Taal volcano. This is an island in the centre of
the Taal or Bombon lake, which is a huge cauldron of water
17 miles long by 11 wide, and is probably the remains of a great
caldera. The Taal volcano is about 760 feet high, dotted over with
small craters, and having one chief crater about three-quarters of
a mile wide; it contains two hot lakes and also a small internal
crater with boiling mud on its floor. A few blocks of lava are
visible, but no flows or dykes can be seen. ‘There have been fairly
frequent eruptions, the most violent of which took place in 1754.

The most striking feature of the photographs reproduced in this
book is the many excellent distant views of the mountains which are
included; the portraying of details of volcanic craters must always
be difficult on account of the impossibility of exhibiting properly the
bowl-like form from any position on the rim even with a lens giving
a very wide angle of view, and also to the presence of clouds of
smoke and steam, but the general view of a mountain is generally
much more satisfactory from a pictorial and also scientific point of

Reviews— Moonta and Wallaroo, South Australia. 89

view, and in this collection full advantage has been taken of this
point by Dr. Anderson. However, the photographs of the craters
of La Soufriére and Bromo are notable exceptions to the above
statement and give the general form of these craters to perfection.

Unfortunately, Dr. Anderson never returned from his last journey
to the East, as he was taken ill on his way home with enteric fever,
from which he died and was buried at Suez. However, Professor
Bonney is to be congratulated on giving to the world this collection
of his photographs, which will be of the greatest service to all
geologists and especially to those who are not so fortunate as to be
able to go out and see the actual voicanoes themselves.

W. H. Witcocxson.

1V.—TueE Gerotocy or THE Moonta anp Wattaroo Minine Disrrict,
Soura Austratia. By R. L. Jack. Geological Survey of South
Australia. pp. 185, with figures, folding maps, and sections.
Adelaide, 1917.

fY\HE mines of the Moonta and Wallaroo area, on Spencer Gulf, are

responsible for a very large proportion of the copper production
of South Australia: up to the end of 1916 they had yielded copper
to the aggregate value of over £19,000,000. This memoir gives
a remarkably clear and well-written account of the geology of an
area which is interesting both from its great economic importance
and from its bearing on general petrological problems, and especially
on the question of the differentiation of igneous magmas. The
formations present are Precambrian, Cambrian, and Tertiary, together
with a thick cover of recent deposits. The Precambrian series
consists of highly altered sediments of various kinds, basic and acid
igneous rocks, and a large mass of felspar-porphyry, which is probably
intrusive in the foregoing: the whole of these are cut by granites
and pegmatite dykes, also of Precambrian age. The productive lodes
of the Moonta area are found in pegmatite dykes cutting the felspar-
porphyry. They do not pass up into the Cambrian strata. The
Cambrian rocks are not of much interest, and only a few small patches
now remain. ‘The Tertiary rock is a thin white or buff limestone,
with fossils; the character of these is not stated in the report.
A large part of the country is occupied by a so-called travertine of
recent date: this is obviously similar to the surface limestones of
South Africa. Along the coast and also in certain inland areas is an
extensive development of sand-dunes.

The pegmatites of Moonta consist of quartz, microcline, and biotite,
with a considerable number of peculiar minerals, especially hematite,
tourmaline, ferberite, scheelite, molybdenite, galena, smaltite,
blende, and apatite. By far the most important copper minerals are
chalcopyrite and bornite. At the surface is an oxidized zone about
100 to 150 feet in depth, with a variety of oxides, sulphates,
carbonates, and chlorides of copper and other metals. Below the
leached caps of the lodes is a zone of native copper: this feature is
difficult to explain. The lodes of the Wallaroo area are found in the
ancient sediments, and are less well defined than those of Moonta,

90 Reports & Proceedings—Geological Society of London.

being more in the nature of impregnations of the country rock, but
the mineral assemblage is similar and is obviously derived from the
same magma, perhaps ata slightly later date, when differentiation had
proceeded further. At a still later stage there seems to have been
a good deal of secondary enrichment by sulphides and chlorides.

This area forms an excellent example of the metasomatic type of
vein deposit, including both sulphidic and oxidic ores. ‘The
connexion between the mineral veins and the granitic intrusions is
particularly clear, and the mineral association is of a distinctive and
peculiar character.

deg daly Jt,

REPORTS AND PROCHHEDINGS.

—————

1.—Gronoeicat Socrrry or Lonpon.

1. December 5, 1917.—Dr. Alfred Harker, F.R.S., President, in the
Chair.

A demonstration on the application of X-rays to the determination
of the interior structure of microscopic fossils, particularly with
reference to the dimorphism of the Nummulites, was given by
E. Heron-Allen, F.L.S., F.G.S., Pres.R.M.S., and J. E. Barnard,
F.R.M.S.

Mr. Heron-Allen said that in the year 1826 Alcide d’Orbigny
published among the innumerable, and for many years unidentified,
nomina nuda that compose his ‘Tableau Méthodique de la Classe
Céphalopodes”’ the name Rotalia dubia. This species was left
untouched by Parker & Jones in their remarkable series of articles
‘¢On the Nomenclature of the Foraminifera”. The French naturalist
G. Berthelin was the first investigator to unearth and make use of
the ‘‘Planches inédites” which had been partly completed by
@’Orbigny for the illustration of his great work upon the Foraminifera,
a work that was never published. Working with Parker & Jones’s
paper, Berthelin made for his own use careful tracings of 246 of
A. d’Orbigny’s unfinished outline sketches. These sketches were
never elaborated by d’Orbigny upon the ‘‘ Planches”’, which are still
preserved in the Laboratoire de Paléontologie under the care of
Professor Marcellin Boule; among them was found the sketch of
Rotalia dubia. On the death of Berthelin the tracings passed into the
possession of Professor Carlo Fornasini, of Bologna, who reproduced
them all in a valuable series of papers published between the years
1898 and 1908. Fornasini’s opinion was that the organism depicted
by @’Orbigny was doubtfully of Rhizopodal nature, and that it was
probably referable to the Ostracoda. The speaker said that he had
examined the d’Orbigny type-specimens in Paris in 1914, and had
noted that Rotalia dubia was a worn and unidentified organism,
resembling an Ostracod.

There the matter rested until Mr. Arthur Earland and the speaker,
while examining the material brought by Dr. J. J. Simpson from the
Kerimba Archipelago (Portuguese East Africa) in 1915, discovered
one or two undoubted Foraminifera of an unknown type, which

Reports & Proceedings—Geological Society of London. 91

resembled Berthelin’s tracing. Professor Boule kindly sent the
d’Orbigny type-specimen to London, and the Rhizopodal nature of
Rotalia dubia was established. It is not a Rotalia, and it must
await determination until more specimens are obtained. It has been
named provisionally Pegidia papillata. There were two or three
forms of the organism, but only one perfect specimen of the
@Orbigny type; and it was undesirable to risk destruction by
cutting a section of it. In these circumstances Mr. Barnard was
approached, and he experimented with the object of ascertaining the
interior structure of the shell by means of the X-rays. His results
were extraordinarily promising, and led to further experiments.

The speaker showed on the screen photographs of the common
and dense Foraminifer Jassilina secans (d’Orb.), followed by a
skiagraph of the same. A skiagraph of the still denser test of |
Biloculina bulloides, d’Orb., shows the arrangement of the earlier
chambers as clearly as it is indicated in Schlumberger’s beautiful
sections. ‘The application of X-rays to the dense imperforate shells
Cornuspira foliacea (Philippi) produced skiagraphs showing the
dimorphism of the shells, both megalo- and microspheric primordial
chambers being clearly distinguishable. Such results led to the
extension of the experiments to the agglutinated arenaceous forms,
of which sections are made with extreme difficulty. ‘The skiagraph
of Astrorhiza arenarta, Norman, shows the internal cavities that
contained the protoplasmic body. ‘T'wo arenaceous forms, Sotellina
labyrinthica, Brady, and Jaculella obtusa, Brady, that are almost
identical in external appearance, are distinguished at once by their
respective skiagraphs, the one exhibiting a simple tubular cavity,
the other appearing labyrinthic.

Mr. Barnard subsequently experimented on still more difficult
material. The massive Operculina complanata, Defrance, the
umbilical portion of which is obscured by a mass of secondary
shell-substance, furnished a clear skiagraph that showed some
curious distortions of the internal septa. Similar results were
obtained in the case of Orbiculina adunca (Fichtel & Moll), another
species overladen with shell-matter. Cyclammina cancellata, Brady,
is an arenaceous form, composed of softer mud and sand, studded
with coarse sand-grains, which make section-cutting almost an
impossibility. The skiagraphs, however, reveal the primordial
chamber and establish the character of this form.

The determination of the Nummulites, depending as it does on
a knowledge of the internal structure of the test, is greatly facilitated
by the application of X-rays, which removes the necessity of splitting
it or cutting sections through it.

The speaker showed ordinary photographs and skiagraphs, made
at slightly varying azimuths, of Vwmmulites levigata and JV. vario-
laria, forms that strew the shores of Selsey Bill. A particularly
notable result was obtained in the case of WV. gizehensis, an organism
that forms the dense masses of Nummulitic limestone of which the
Pyramids of Egypt and the Citadel at Cairo are built.

Mr. Barnard said that, although the utilization of X-rays to
determine the internal structure of various bodies was well known,

92 Reports & Proceedings—Geological Society of London. |

he was not aware that the method had been successfully applied to
small objects, such as Foraminifera. After he had begun his
- experiments he found that M. Pierre Goby had done some work in
this direction in France, but the method as he described it is
surrounded with considerable mystery and elaboration of apparatus,
which appear quite unnecessary. The speaker’s results were arrived
at independently ; in fact, they are really a side issue.

His original experiments were directed rather towards the use of
X-rays in obtaining magnified images, altogether apart from the
usual skiagraphic methods in which a shadowgraph is, in fact, all
that can be produced. The primary object has not yet been achieved,
although there is some reason to hope that it may ultimately come
to pass. The results shown by Mr. Heron-Allen are obtained by
quite simple means. A very narrow beam of X-rays, such as would
be termed ‘‘a parallel beam” when speaking in terms of ordinary
light, is allowed to impinge on the object, the latter being in contact
with the photographic plate. The negative produced is, therefore,
of the same size as the object. Photographie enlargement is then
resorted to, and the result had been shown on the screen. There are
two points to which careful attention is required if success is to be
achieved.

The quality of the X-rays must be suited to the object. In nearly
all cases of small objects, what are known as ‘‘ soft’ X-rays must be
used, and the degree of softness is the crux of the whole matter.
The photographic plate must be of exceedingly fine grain, otherwise
the amount of enlargement that can be obtained is very limited.
Difficulties in this direction have been overcome, and Mr. Heron-
Allen has stated that the results are of considerable biological value.

Dr. A. Smith Woodward, F.R.S., V.P.G.S., exhibited a radiogram
of the original slab of lithographic stone containing the skeleton of
Archeopteryx, made for the British Museum by Dr. Robert Knox in
1916. It was evident that the penetrability of the fossil bones to
the X-rays was the same as that of the surrounding matrix. The
only portions of the skeleton visible in the radiogram were those
more or less raised above the general surface of the slab. This result
accorded with that obtained bv Professor W. Branca when he
similarly experimented with the Berlin specimen of Archeopteryx.

2. December 19, 1917.—Dr. Alfred Harker, F.R.S., President,
in the Chair.

The following communication was read :—

‘““The Chellaston Gypsum-Breccia considered in its relation to
the Gypsum-Anhydrite Deposits of Britain.” By Bernard Smith,
M.A., F.G.S.

This communication is designed to clear up some of the ambiguities
that have arisen with regard to the actual mode of formation of the
deposits of gypsum in Britain—chiefly from the point of view of
the field observer. An attempt is made also to show the true

Reports eZ Proceedings—Hdinburgh Geological Society. 93

relationship of the gypsum. to the beds of anhydrite with which it is
sometimes associated.

A description is given of a remarkable breccia occurring at
Chellaston in Derbyshire, and its origin is discussed. Important
occurrences of gypsum in other parts of the country, as well as the
alternative theories as to their mode of formation, are then reviewed
in the light thus obtamed.

The remainder of the paper deals mainly with the possible
interchanges between anhydrite and gypsum. ‘The place and
the function of the fibrous form of gypsum are indicated, and
a nomenclature is suggested for certain isolated masses of the
mineral,

The chief conclusions are as follows :—

1. At Chellaston the gypsum was laid down as such, and has
suffered no appreciable alteration or addition since the time of its
original deposition and brecciation. There is no evidence that the
rock was ever anhydrous.

2. By comparison with this deposit, and also by independent
evidence, if seems probable that most of the important beds of
gypsum in the country were laid down as gy pon, and have behaved
throughout as stratified deposits.

3. When anhydrite is present, the evidence favours the view that
it is original, and was deposited in a stratiform manner in sequence
with gypsum.

4. Microscopic evidence shows that there has been, in some cases,
an alteration of anhydrite into gypsum where the two minerals were
in original juxtaposition; this alteration, however, is considered to
have occurred at, or immediately after, the time of deposition, and
to be confined to the existing plane of contact of the two minerals.

Il.—Epinpured Grotocican Socrery.
December 19, 1917.—Professor Jehu, President, in the Chair.

1. ‘‘Marginal Intrusive Phenomena near Linlithgow and at
Auchinoon.” By T. Cuthbert Day, F.C.S., F.R.S.E. (Illustrated
by lantern views and rock specimens. )

At Hillhouse Quarry, near Linlithgow, the dyke of white trap
with its branches has produced considerable contact alteration in the
limestones and shales, while the thick sheet of columnar olivine
basalt which overlies the sediments does not appear to have caused
any change; it, however, transgresses the strata considerably,
which, it is ‘suggested, may be due to contemporaneous erosion and
that the basalt may prove to be a lava.

It was pointed out that the pecular brecciation seen in certain
bands of dolerite at Cockelrue which have been enclosed in the
intrusive mass of the hill is probably due, not to crushing or move-
ment, but to numerous crack joints produced on cooling.

The dolerites of the district do not readily take the form of white
trap when found in contact with carbonaceous shales.

A large exposure of intrusion breccia was described in a quarry of

94 Reports & Proceedings—Mineralogical Socvety. — :

dolerite at Kettlestoun, composed of fragments of igneous and sedi-
mentary rocks cemented together by dolerite, and occupying a large
part of one face of the quarry. A peculiar spotted shale, due to
contact alteration, in the same quarry was also described.

In connexion with the exposure of dolerite and overlying hornfels
at Auchinoon, it was stated that a quantitative analysis of the
alkalies in the dolerite showed a considerable falling off as the
margin was approached, and that while the hornfels in contact
showed nearly 7 per cent alkalies, no trace of lime was found in the
specimen analysed.

2. **On a Section of the Wardie Shales, with Intrusions, exposed
in the Stank at Corstorphines, and on the Draining of the Old Lochs
at Gogar and Corstorphine.”” By D. Tait.

The main purpose of the communication was to eee a hitherto
unrecorded section of the Wardie Shales in the Stank at the west end
of Dovecot Road, Corstorphine. The beds there consist of sandstone
and shales, dipping west at 20°. These are cut by two east and
west quartz dolerite dykes, which alter the shales in their vicinity.
The section is on the south side of the Middleton Hall fault, the
position of which is probably indicated by a spring of water situated
a few yards north of the locality. It was pointed out that this
section lies between Gogar Loch and Corstorphine Loch, both now
drained, and also midway between the buried river channels of the
Almond at Turnhouse and the Water of Leith at Roseburn. Both of
these channels are below sea-level at these points. It therefore
appears probable that the rocks in which this section was excavated
formed a watershed between them in pre-Glacial times.

Photographs of a series of old maps, chronologically arranged,
were thrown on the screen to show the progress of draining of Goear
Loch and Corstorphine Loch. An Act of Parliament ahome us that
these draining operations were in progress in 1661. Their final.
stage is recorded in the New Statistical Account, which says that
about 1831 the Stank was widened and deepened.

I1I.—Mineratoeican Socrery.

January 15, 1918.—W. Barlow, F.R.S., President, in the Chair.

Dr. J. W. Evans: ‘‘ Diagrams expressing the Composition of
a Rock.” These diagrams are intended, like “those of Michel Lévy
and Miigge, to indicate at a glance the significance of the analysis of
a rock or complex mineral silicate. The molecular proportions of the
constituents are determined in the usual manner, those of the ferrous
and magnesium oxides, however, being doubled. The silica is
represented by two rectangles placed side by side, the length of
each being half the molecular proportion of silica. In one of these
rectangles lengths equal to the molecular proportions of potash, soda,
and lime are measured off in succession, and in the other those of
alumina, iron oxide, and magnesia. Thus, the same space represents
both metallic oxide and silica, and so far as felspars, felspathoids,
or egirine are actually or potentially present, the monoxide and
sesquioxide they contain are with two molecules of silica represented

With

Ouituann SW As Papen 95

by contiguous portions of the two rectangles. The excess, if any,
ot lime over available alumina has the silica necessary to form
wollastonite, and the excess, if any, of iron oxide over available soda
and the magnesia have the silica required to form orthosilicates.
The remaining silica space is then divided up to show the additional
silica required or available for the felspars, felspathoids, and egirine,
and that available to convert the orthosilicates of iron and magnesium
into metasilicates. The remainder represents free silica or quartz.

Dr. G. F. Herbert Smith: ‘‘ On the use of the Gnomonic Projection
in the calculation of Crystals.’”’ If projected on to a plane at right
angles to the edge of the zone containing the poles from which
biangular measurements were made, the diagram takes the form of
a net, the nodes of which represent the principal poles. » The unit
lengths of the net are easily calculated from the data, and once the
rectangular co-ordinates of any node with respect to axes on the
diagram have been determined those of the remainder follow by
simple addition or subtraction; the corresponding spherical angles.
are deduced by a simple calculation. The accuracy of the calcula-
tions may be checked from the diagram at every step. To keep the
projection corresponding to any crystal within reasonable dimensions
it is sometimes convenient to project on to the faces of acube. The
direction of a zone when crossing from one face to another is very
simply found from the diagram.

QySieIo Of NISL Sse

WILLIAM ALBERT PARKER, F.G.S.
Born 1855. DIED JANUARY 14, 1918.

We deeply regret to record the death of Mr. W. A. Parker, of
Rochdale, which took place on January 14 at the age of 63. For
many years he was a highly esteemed schoolmaster in Rochdale.
Here he indulged his taste for scientific research, especially geology,
and became associated in friendship with a small but enthusiastic
body of geologists, including, amongst others, Walter Baldwin, the
late W. H. Sutcliffe, Dr. March, James Horsfall, Robert Law, and
S. S. Platt. Assisted by other members of this band Mr. Parker
specially devoted himself to the task of working out the beds of
shale, with ironstone nodules containing fossils, of Middle Coal-
measure age at Sparth, Rochdale. This led to the discovery of
a numerous and rich series of fossils, including rare Orthopterous
insects, Arachnida, and Crustacea, many of which have been figured
and described in the Groroeican Macazinr (see volumes for 1907,
pp. 400-7, 589-49; 1911, pp. 361-6; 1913, pp. 852, 856). A new
Crustacean, Rochdaleia Parkert, was named after our friend. Many
of these valuable specimens are now preserved in the Manchester
Museum and in the British Museum (Natural History). His loss will
be keenly felt by a large circle of geological friends in the Midlands.

Eis

96 Miscellaneous.

MISCHLLAN HOUS.

JUBILEE OF A. GovVERNMENYT GEOLOGIST.

Mr. R. Bullen Newton, F.G.S., of the Geological Department,
British Museum (Natural History), has just completed fifty years
active Government service. During the earlier part of his official
career, which commenced on January 6, 1868, Mr. Newton was one
of the Assistant Naturalists of the Geological Survey under the late
Professor Huxley. He was transferred to the British Museum in
August, 1880, at the time of the removal of the Natural History
Collections to Cromwell Road, in which he took an active part. His
numerous published researches on various branches of paleontology,
especially the Mollusca and Foraminifera, have had a distinct
bearing on the geology of widely scattered regions. He has been
Preaden: of the Malacological Society of ibamdion and of the Concho-
logical Society of Great Britain and ireland. We offer Mr. Newton
our congratulations on his extended and valuable scientific labours.

F. W. Roper, 1.8.0., F.G.S. (1840-1915).

Our readers will remember that in the summer of 1915 the
University College of Wales, Aberystwyth, became the possessors
of the library and lifelong collections of the late F. W. Rudler,
who was Professor and Dean of the College in the years 1876-80,
and subsequently Curator of the Museum of Practical Geology,
Jermyn Street, London."

His library, consisting of some 2,000 volumes and 4,000 pamphlets,
has been tabulated and cross-indexed, and his extensive collection of
rocks, fossils, etc., carefully labelled. The Mineralogical Collection
has been made available for teaching and demonstration purposes,
while the archeological and other specimens have been added to the
College Museum. The additions thus made to the College, further
assisted by the foundation of the ‘“‘ F. W. Rudler Geological Research
Scholarship”, have greatly increased the facilities for students,
particularly in the subject ‘of geology.

Monsieur Jules Bernaerts, the eminent Belen sculptor (of the
Royal Academy of Brussels), has executed a life-size medallion of
Professor Rudler, which has been framed in oak and placed in the
wall of the College Quadrangle, and below it a brass tablet (executed
by Messrs. G. Maile & Son, of Euston Road, London), bearing the
inscription, ‘‘In memory of F. W. Rudler, 1.8.0., F.G.S., 1840—
1915. Professor in this College 1876-80, and Founder of the College
Museum,” has been affixed to a polished slab of Welsh marble
specially cut for the purpose from the Narberth Quarries.

Professor Rudler’s numerous friends and all concerned in the
welfare of the College will be pleased to know that the collections
which he formed with so much ability have thus been made available
for the furtherance ofthose studies in which he was so deeply
interested and to which he devoted the labours of a lifetime. On
behalf of the College.—S. G. Ruptmr, one of the Governors.

THE UNIVERSITY COLLEGE OF WALES, ABERYSTWYTH,
January 7, 1918.
1 For obituary and portrait see GEOL. MAG., 1915, pp. 142-4.

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ASSISTED BY ;
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4 {i Dr. GHORGE J. HINDE, FR-S., E.G.S. #4 a
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1 DR. JOHN HDWARD MARR, M.A. Sc.D. (Canr.), F.R.S., P.G.S. - :
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ay MARCH, 1918.
| .
GeO NWSE now aS
ae I. OniGInaL ARTICLES. Page NOTICES OF MEMOIRS (cont.). Page
New or imperfectly known Chalk Age. By Marsden Manson, C.E., a
Polyzoa. By R. M. BRYDONE, 3 BAe se oes ee inden oma EM ops ba ce 1294 4)
F.G.S. (Plate VI.) .............. 97 | John Michell and Martin Simpson. 131 7~
The lias of South Lincolnshire. 2
Tl. Reviews.
By A. EH. TRUEMAN, M.Sce., re 5) us
F.G.S. (With three Text-figures:) British Resources of Sands used
© Concluded.) /.......s0000.. Ses 101 for Glass, ete. By Professor
Mountain Building. By KR. M. P. G. H. Boswell ......0.......... 181
DbELEY, M. Inst. C.H.,V.P.G.8. 111 | Phosphates of Saldanha Bay. By
Datum-linesin the English Keuper. 4 Bes ! Le du Toit... ams poe 138
By R. L. SHERLOCK, D.Se., | Building and Ornamental Stones
A.R.C.Sce. E.G S (With a of Canada. By W: A. Parks 133
Seation.) ieee ew er ok j99 | Geology of the Transkei, South
- ANoteon Isostasy. By A. MoRLEY Africa. By A. Ti. du Toit perce, 135
DAVIES ERE. See oc. Low-temperature Formation of
kG S. Imperial College of Alkaline Be eval in Limestone.
Science and Technology ......... 125 By R.A, Daly.. feose ceettaee FBO
IY, REPORTS AND EA eT
ai II. Novicks OF MEMOIRS. Geological Society of London—
_ A Hyena-den in Iveland. Report Sam aye one TOs kar alte aseeoates 136
} by R. F. Schartf and others ...... 127 TAMU eames anes aes One
: Fossil Man in South Africa. By MebuuainGetai. sete cn ee seenen eS
Dr. Broom and others ............ 128 Me butiatiys2 OFM Racca ep 142
| Factsrevealed by Antarctic Research Edinburgh Geological Society ...... 143
‘ | bearing upon Problems of the Ice oo SSGGUUULOM sve sate gna: 144

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THE

GHOLOGICAL MAGAZINE

NEW SERIES. DECADE Ni. i VOLE NM.

No. III.—MARCH, 1918.

ORIGIINAI ARTICLES.
—

I.—NorEs oN NEW OR IMPERFECTLY KNOWN CHaLK Poryzoa.
By R. M. BRYDONE, F.G.S.
(Continued from the January Number, p. 4.)
(PLATE VI.)
PseuDOSTEGE concursA,’ sp. nov. (Pl. VI, Figs. 1--3.)

Zoarium incrusting, with a tendency to grow in bands: the
general surface stands high and shows no trace of zocecial boundaries ;
it is much rumpled, apparently unsystematically, but is only
broken by the zocecial peristomes; these are short tubular
prominences inclined slightly forwards but bent upwards at the
ends so as to end in a plane parallel with the general surface: the
apertures are on the whole circular, but very rarely truly so, and
occasionally very irregular; they vary in internal diameter from
‘08 in a small specimen such as Fig. 2 up to’l15mm. in a large
specimen such as Fig. 38; the peristomes are thick and each has
from one to four pores init; these pores are generally small and
round, but occasionally among the larger ones are found definite
instances of arrowhead shape which makes it possible that all are
avicularian: round the edges of the zoarium there is a fairly
complete fringe of simple shallow Membraniporiform zoccia, with the
general surface either ending abruptly above them or sloping gradually
down to them.

Oecia small and globose, perched on or sunk slightly into the
anterior part of the peristome, very erratic in occurrence.

Avicularia of two kinds—(qa) accessory, as above described,
(6) vicarious, of hour-glass type with the upper lobe much elongated,
the lower very short and devoid of internal front wall and indications
of a transverse bar at the point of maximum constriction; these
occur at or near the edge of the zoarium.

This species is referred only provisionally to Pseudostege, as I do
not feel confident that the fringe of Membraniporiform zoccia
really represents a primary stage, nor am I clear as to how exactly
the general zoarial crust is developed. The species is introduced
here because it occurs at the same horizon in Hants, about the
junction of the zones of 4. guadratus and B. mucronata, as several of
the Membraniporelie I have just been describing, and presents so

1 The term Psewdostega has been used for a division of the Cheilostomata,
presumably as a neuter plural. This term is not therefore identical with my
genus Pseudostega (GEOL. MaG., 1910, p. 259), which is a feminine singular,
but to avoid any risk of confusion it is perhaps as well to amend my term to
Pseudostege.

DECADE VI.—VOL. V.—NO. III. 7

98 R. M. Brydone—New Chalk Polyzoa.

many points of resemblance (apart from the Cribriline surface) to
some of them, e.g. I. thoraceformis and If. Shawfordensis that it
seemed bound to be a member of that group with a complete
secondary front wall. Ihave not, however, been able to find any
trace of Cribriline structure about it. It seems to lead almost
directly to

CELLEPORA (?) DiasTorpEs, sp. nov. (Pl. VI, Fig. 4.)

Zoarium incrusting, consisting of a common crust out of which
arise long tubular, slightly barrel-shaped zocecia, free for the greater
part of their length, inclined strongly forwards but sometimes
turning erect at the end; they have slightly thickened peristomes, in
which there may be from one to three pores, one in the middle of
the posterior part being fairly regular; these pores can often be seen
in the larger zocecia to be the apertures of tubuli mainly embedded
in the zocecial wall; the apertures are more or less circular, but
sometimes very irregular in shape: the occia are very small,
globose, perched on the anterior part of the peristome and over-
hanging the greater part of the aperture: there is a partial fringe
of shallow Membraniporiform zocecia.

This species is fairly common at Trimingham, and is probably to
be found in the Norwich Chalk, as I have specimens from Norwich
and Weybourne which seem to be inchoate forms of this species.
It is so clearly in most respects a development from Pseudostege
concursa (ante) that it is rather surprising that there should be
no trace of vicarious avicularia. Apart from the ocecia and the
peristomial pores it might easily pass for a sturdy Dvuastopora.

% % *

There is a large group of Membranipore in which a pair of pores
or tubes at the anterior end are repeated with great regularity and
another group in which a single tubular prominence occurs very
persistently at the posterior end of the aperture. Both are well
represented in the English Chalk, and they might be expected to be
always easily distinguishable, but this is not the case. I propose to
_deal with some of the English species of these groups in order of
seniority.

MemBRANIPORA SEAFORDENSIS, sp. nov. (Pl. VI, Figs. 5, 6.)

Zoarium unilaminate, normally incrusting, occasionally free.

Zoecia of medium size, average length ‘5 to-6 mm., breadth -4mm.,
with thin common side-walls; apertures naturally widely oval, but
rendered irregularly polygonal by intrusion of the edges of the more
or less rounded protuberances, with small round or elliptical apertures,
of which a pair is set with extreme regularity on the front wall of
every zocecium anteriorly to the ocecium; these protuberances
appear to be accessory avicularia of the small beak-shaped type in
a primitive stage; sometimes they become confluent.

Oecia occur with very great regularity: they are set on a shelf so
deep within the aperture at the anterior end that their tops are little
more than flush with, or may even be below, the general surface ;
their apertures appear to be very strongly cut back, so that the
visible top is very much shorter than the basal shelf: the latter is

kh. M. Brydone—New Chalk Polyzoa. 99

indicated in a few zocecia at the top of Fig. 5, from which the
ocecia have been broken away.

The species is fairly regular in occurrence in the zone of
I. cor-testudinarium at Seaford. It is fairly intermediate between
the published figures of Flustrina constrieta, D’Orb.,1 and F. ovalis,
D’Orb.,? but Canu i in his “ Revision ” throws doubt upon the validity
of either of these species.

MEMBRANIPORA MULTIFISSA, sp. nov. (Pl. VI, Figs. 7, 8.)

Zoarvum unilaminate, incrusting.

Zoecia of medium age. average length 5 to°6mm., breadth '4mm.,
without any definitely visible interzowcial sutures; apertures
broadly oval, flattened at the anterior end, enclosed by rather rounded
margins which approach one another rather closely laterally but are
quite distant longitudinally; a pair of rather large sub-tubular pores
occur very regularly on the outer edges of the margins just beside
the anterior end of the aperture, while between the margins there
are numerous irregularly scattered and less pronounced openings,
some of which are tubular, while others are mere fissures possibly
along zocecial boundaries.

Oecra fairly abundant, always broken, semicircular in ground plan.

Avicularia probably of two kinds—(a) accessory, represented by
the paired marginal pores, (4) vicarious, scarce, of hour-glass type,
with a long area of constriction, traces of a cross-bar at its lower end,
a narrow internal front wall in the short round anterior lobe, and no
internal front wall in the small posterior lobe, which has a very
slender rim marked off by a little furrow, a feature not brought out
by the photographs.

This species occurs in the zone of IL. cor-anguinum at Gravesend.
The relative size of its paired pores, no Jess than its possession of
vicarious avicularia, distinguish it from any figured species, except
I, dolium, Bryd.

MEMBRANIPORA SEVINGTONENSIS, sp. nov. (Pl. VI, Fig. 9.)

Zoarium unilaminate, free.

Zoecia large, average length:7 mm., with oval apertures narrowing
considerably to the anterior end, which is flattened by the edge of an
inward sloping shelf, and surrounded by raised margins almost in
contact with one another and bearing from seven to nine pairs of blunt
imperforate denticles, of which those round the anterior end are very
slender: at the foot of nearly every zocecium there is a large, more
or less semicircular, hollow thin-walled protuberance, which is
probably avicularian; between this and the aperture the raised
margin dies away and the tubercles disappear; there are no other
indications of avicularia.

Owcia occurring erratically, shortly and widely conical with
rounded ends and a free edge apparently almost straight; when they
are present that part of the apertural margin which they embrace
does not undergo any depression, but is bare of tubercles; they may
push to one side the protuberances of the succeeding zocecia or cause
them to be absent.

1 Pal. Crét. Franc., vol. v, p. 304, pl. 702, figs. 5-7.
2 Loe. cit., p. 304, pl. 702, figs. 8-10.

100 R. M. Brydone—New Chalk Polyzoa.

This species was found in the zone of U. cor-anguinum at Sevington,
in Hants. It has obvious relationship with the figure of Flustrellaria
granulosa, D’Orb.,' but that figure must be quite unreliable, as Canu,
in his ‘ Revision” , unites the ty pe with Plustrellarta dentata, a widely
different form. waco Sree

MEMBRANIPORA SANDALINA, sp. nov. (Pl. VI, Fig. 10.)

Zoarium unilaminate, incrusting.

Zoecia of medium size, average length ‘6mm. with small oval
apertures from ‘3 to °35 mm. in length, tapering considerably to the
flattened anterior end and surrounded by broad, rather indefinite
inward-sloping margins, which arise out of a common crust rather
sharply in the anterior part, but die away posteriorly: at the anterior
end there is a pair of small pores high up on the inner side of the
margin just behind the end of the aperture, and a pair of tiny pores
on the outer edge of the margin at its corners just outside the points
from which the occium starts: the pair of small pores occurs with
very great regularity, and as the pair of tiny pores can almost always
be detected when the presence of an ocecium assists the search,
it also is probably always present: at the posterior end of the
aperture there is, or rather there should typically be, a central
hollow protuberance rather like the front half of a email laid with
the toe pointing away from the aperture; this is actually the case
with zowcia which do not have to accommodate the occium of
another zoceclum, and sometimes even when. this accommodation
has to be provided ; but in the latter case, as a rule, the protuberance
is displaced by the ocecium and splits into two rather emallcy
lateral ones.

Owcia very regular in occurrence, long and helmet-shaped, with
apertures cut a long way back. |

Avicularia probably of two kinds: (a) accessory, the protuberances
above described; (0) vicarious, rather scarce, of the hour-glass type,
elongated and narrow, with very little infold in the centre, no
internal front wall in the lower lobe, and an inflated external front
wall at the posterior end. —

This species, too, occurs in the zone of WU. cor-anguinum at
Gravesend. The two preceding species can obviously be referred to
one of the two groups mentioned above. This species not only
combines the characters of the two groups, but exhibits an actual
passage of the character of the second group into a very plausible
imitation of the character of the first group.

EXPLANATION OF PLATE VI.

Fic, (All figures x 12 diams.)

1, 2.. Pseudostege concursa. Zone of A. quadratus. Shawford, Hants.
ROR - Si Zone of B. mucronata. Portsdown, Hants.

4. Cellepora diastoides. Trimingham.

6. Membranipora Seafordensis. Seaford, Sussex.

8. es multifissa. Gravesend, Kent.

9. pan Sevingtonensis... Sevington, Hants.
10. A sandalina. Gravesend, Kent.

5,
7;

+ Pal. Crét. Franc., vol. v, p. 525, pl. 725, figs. 1-4.

Grou. Mae., 1918. Prats VI.

R. M, Brydone, Photo. Bemrose d&: Sons Ltd., Collo.
Chalk Polyzoa.

A, EB. Trueman—The Lias of South Lincolnshire. 101

Il.—Tue Lirias or Sourm LincotnsHire.

By A. EH. TRuEMAN, M.Sc., F.G.S., formerly Research Scholar, University
College, Nottingham,

(Concluded from page 73.)

UT while it is difficult to collect fossils in situ in the upper part
of the Lower Lias, a very good knowledge of the fauna is
obtained from the material which may be collected on the tunnel
heaps between Old Dalby and Saxelby. I have been permitted to
study the large collection of specimens from these heaps which are
preserved at University College, Nottingham, and the Engineer of
the Midland Railway Company gave me leave to make small
excavations. ‘lhe following lists give some idea of the fauna, which
contains abundant Ammonites, especially of the genera Zragophyllo-
ceras, Polymorphites, and Platypleuroceras. The Foraminifera like-
wise are unusually interesting ; a list of genera identified by Wilson
has already been given by Quilter’; according to the list given by
H. B. Woodward? no Zextularia-like form is known from the Lias
of any other British locality.

Fossils.

Cf. Asteroceras sagittarvum.
Acanthopleuroceras cf. valdani,
d’Orb. (rare).

Cf. Cymbites levigatum, Hyatt (rare).

Deroceras aft. armatwm, Sow.
Oxynoticeras flavum, Simps.
O. cf. polyophyllum, Simps.
O. oxynotum, Qu. (rare).

Platypleuroceras cf. brevispina, Sow.

P. aureum, Qu. (abundant).

P. sp. noy. (with knotted venter).
P. rotundum, Qu. (abundant).

P. Birchioides, Qu.

Polymorphites jupiter, d’Orb. (rare).
P. cf. jupiter, d’Orb. (common).

P. caprarws, Qu.

P. mixtus, Qu. (abundant).

P. trwialis, Bean-Simps.

P. costatus, Qu.

Tragophylloceras ambiguum, Simps.
T. aff. numismale, Qu.

T, loscombi, Sow. (abundant).

T. cf. 1bex, Qu.

Nautilus intermedius, Sow. (rare).

Belemnites cf. charmouthensis, Mayer.

B. acutus, Mill.
Acteonima sp.
Amberleya conspersa, Tate.

Cerithium liassicum, Moore (abun-

dant).
Chemmitzia (?) semitecta, Tate.
C. citharella, Tate.
Cryptenia (?) consobrina, Tate.

Hucyclus sp.

Pleurotomaria anglica, Sow.
Trochus dalbiense, Wils.

Turbo sp.

Turritella trigemmata, Wils.
Arcomya elongata, Roem.

Astarte ef. striato-sulcata, Roem.
Cardinia cf. levis.

Ceromya sp.

Gryphea cymbiwm, Lam. (abundant).
G. (?) incurva, Sow.
Hippopodium ponderosum, Sow.

(abundant).

Macrodon intermediwm, Simps.
Modiola scalprum, Sow.

M. cf. hillanoides, Chap. & Dew.
M. sp.

Nucula sp.

Nuculana (Leda) subovalis, Goldf.
N. (L.) minor, Simps.

N. (L.) complanata, Goldf.

N. (L.) galathea, d’Orb.

Pecten priscus, Sch.

P. sp. nov.

Pholadomya glabra, Agass.

(= ambigua, Sow.).
Plewromya aff. costata, Y. & B.
Plicatula spinosa, Sow.
Rhynchonella fodinalis, Tate.

R. lineata, Y. & B.
Spiriferina cf. Walcotti, Sow.
Waldheimia lagenalis, Qu.
Cincta numismalis, Qu.

1. E. Quilter, ‘‘ Lower Lias of Leicester’’?: GEOL. MAG., 1886, p. 64.
2H. B. Woodward, Lias of England and Wales, 1893, p. 377.

102 A.B. Trueman—The Inas of South Lincolnshire.

Montlivaltia mucronata, Dune.
_M. Haimei, Chap. & Dew.

Hatracrinus Britannicus, Sch.

Serpula sp. ;

Ditrypa etalensis, Piette.

Cytheridea sp.

Holothuroid plates.

Cristellaria cf. convpressa, d’Orb.

D. sp.

Frondicularia intumescens, Born.
fF. cf. Terquemt, d’Orb.

Ff. sp.

Glandulina sp.

G. (?) paucicosta, Roem.
Lingulina tenera, Born.
Marginulina reversa, T. & B.

C. crepidula, F. & M. Miliolina (Spirillina) sp.
C. recta, d’Orb. Nodosaria radicula, Linn.
C. rotulata, Lam. N. sp.

C. varians, Born. ef. Nonionina sp.
Dentalina convmunis, d’Orb. Orbulina universa, d’Orb.
D. glandulosa, Terq. Textularia sp.

Judging from a less complete list of fossils Mr. B. Smith? was
able to infer the presence of representatives of the zones from
oxynotus to jamesont. From the above it is now possible to assert
that the beds from Oppel’s zone of A. oxynotus to that of A. cbex are
represented. The record of Deroceras davei, Sow., from Old Dalby ?
suggests that still higher beds are present, but the specimen bearing
that name in the Leicester Museum, to which the record presumably
refers, is wrongly identified, being simply a species of Lytoceras.

The association of fossils from such diverse horizons on a single
heap, or series of heaps, is rather confusing, but it must be remembered
that the material composing the heaps has been accumulated from
some two hundred feet of clay, which is approximately the thickness
of the zones named in Yorkshire. It was pointed out by Quilter,’
however, that species are to some extent confined to definite parts of -
the spoil heaps. ‘Thus, on the lower spoil heap may be found fossils
from the oxynotus zone, with numerous Gryphee, Pholadomya, and
Corals, while the upper heap is rich in Platypleuroceras, Poly-
morphites, Tragophylloceras, and crinoid stems from the zbex zone
(valdani zone of Buckman). ‘he clays on the heaps at the Saxelby
end of the tunnel doubtless represent the upper part of the dex
zone, but they are less fossiliferous.

The upper part of the Lower Lias ( O/stoceras sub-zone) 1s exposed
at Waddington Brick Pit, a few yards east of the railway station.
About twenty feet of blue shales are here seen, weathered yellow at
the top. The nodules are very fossiliferous, each containing one or
more capricorn ammonites, chiefly Ovstoceras figulinum, O. omissum,
and O. curvicornum. ‘‘ Androgynoceras”’ cf. capricornum, Wt., and
Amblycoceras crescens, Hyatt, are also common. A single specimen
of the zone fossil, Deroceras dave’, was also found here; apparently —
this is the most northerly English record for this fossil, which is
fairly common in beds of this age in the South of England.

Fossils.

Deroceras davei, Sow. (very scarce). O. figulinum, Simps. (abundant).
Oistoceras omissum, Simps. (abun- Amblycoceras crescens, Hyatt (not
dant). uncommon).

1 B. Smith, Geology of Melton Mowbray (Mem. Geol. Surv.), 1909, p. 37.

2 C. Fox-Strangways, Geology of Leicester (Mem. Geol. Surv.), 1903, p. 108.

3-H. E. Quilter, ‘‘ Lower Lias of Leicestershire ’’?: GEOL. MAG., Dec. III,
Vol. III, p. 59, 1886.

A. H. Trueman—The Inas of Sowth Lincolnshire. 103

A. sp. C. sp.
** Androgynoceras’’ aft. maculatum, Dentalina brevis, d’Orb.

Y. & B. D. communis, d’Orb.
A. cf. capricornum, Wt. (abundant). _D. ef. nodosa, d’Orb.
Belemnites clavatus, Blainv. D. glandulosa, Terq.
B. milleri, Phill. D. spp.
Avicula inequivalvis, Sow. Frondicularia Terquemt, d’ Orb.
Leda sp. F’. intumescens, Born.
Lima eucharis, d’Orb. (rare). Lingulina tenera, Born.
Pecten equivalvis, Sow. (common). Marginulina Rimeri, Reuss.
Protocardium truncatum, Sow. Nodosaria raphanistrum, Linn.
Ehynchonella cf. rvmosa, Qu. N. sp.
Cristellaria crepidula, F. & M. Trochamina sp. (?).

A similar fauna characterizes the lower beds exposed at Brace-
bridge, a mile north of Waddington, but this section is more
conveniently considered later.

3. MippLE anp Upper Lias.

A. Lincoln District.

The best exposure of Middle Lias and contiguous deposits in this
area is seen at Bracebridge Brick Pit, about three miles south of the
Cathedral, Lincoln, where the following section is exposed :—

ft. in.

tenuicostatum Grey paper shales, weathering orange, with layers

sub-zone. of flat, green nodules containing Inoceramus.

15ft. 3in. + Dactylioceras cf. tenwicostatum, D. senicelatum,
Posidonomya bron . . 15 0

Impersistent band of dark earthy nodular limestone,

f with well-preserved ee bronni. ‘‘ Cone-
in-cone ’’ structure : 3

acutum sub- Greenish shale with Tiltoniceras sacutum, T. costatum. 5

zone. 3ft. Dactylioceras athleticum. D. ct. tenuicostatum,
Leptena sp. ; : 6 4

Light-grey shale with Dactyloids (D. athleticun.,

D. cf. hollandrei), Protocardium sp., ne
hybrida : 2 8

spinatum Light-grey shale with scattered phosphatic nodules ; ;
zone. ‘Paltopleur oceras spp. . 1 @

19ft. 10in. Layer of ferruginous nodules with many phosphatic
nodules 6

Light-grey shales with scattered phosphatic nodules ;
Paltoplewroceras spp.; some beds full of Pr oto-
cardium truncatum, Dentalium giganteum, and
Gomomya hybrida : . 14 0

Main Nodule Bed; variable, but usually ‘consists of
two beds of brown ironstone separated by green
shales with phosphatic nodules. Pecten equivalvis,

P. lunularis, Avicula cygnipes, Leda (Nuculana)

graphica, Belemnites sp., Rhynchonella sp. . . 2 4
Grey shales with Paltopleur oceras spp. Many

Lamellibranchs 2 0
margaritatus Dark-grey micaceous shales with levers of ironstone
zone. 30 ft. nodules. Amaltheus margaritatus, A. gibbosa,

A. levis, Sequenziceras spp., Modiola scalprum,
Nuculana Quenstedti, Ostrea sp., Gresslya spp.,
Plicatula spinosa, P. calvus, Hucyclus imbricatus,
Cryptenia consobrina . : 5 : ; plone

104 A. E. Trueman—The Lias of South Lincolnshire.

ft. in.
Dark-grey micaceous shales with ferruginous con-
cretions in beds and scattered. Amaltheus spp.
(common). Oistoceras spp. and ‘‘ Androgynoceras’?
spp. (decreasing towards the upper part). Modiola
subcancellata, Goniomya hybrida, Cucullea

miinstert, Gresslya spp., Pecten spp. . .15 0

Oistoceras Dark-grey shales with reddish pyzitic nodules, con-
sub-zone, taining Oistoceras figulinwm, O. omissum, O.
Lvparoceras curvicornum, ‘* Androgynoceras’? capricornum
sub-zone, (Wright), Amblycoceras crescens, Beaniceras aff.
and luridum, Liytoceras sp., Gresslya spp., Leda

latecosta (Nuculana) spp. . 15 0
sub-zone. Dark-grey clunchy clay with nodules and two. shell

beds, with capricorn ammonites, Gresslya lunulata,

Pecten spp., Plewromya granata, Cucullea sp.,

Plicatula spinosa : . 10 0
Dark-grey shales with scattered nodules. " Capricorn

ammonites less common, Androgynoceras cf.

‘striatum’, Lytoceras ct. lineatus, Wt. (non Schl.),

very abundant. Goniomya hybrida, Pecten equi-

valvis, P. calvus . : ‘ : 3 . 10 O

(The bottom 20 feet was examined during the construction of
a reservoir at the northern end of the pit in 1917 and is not now
_ visible.)

The most remarkable feature of the fauna is the abundance and
variety in the Ovstoceras sub-zone of the capricorn ammonites, which
with the ‘‘spherocones”’ or ‘‘ strvatum”’-like forms evolved. from
them pass into the lower part of the margaritatus zone. Thus species
of Amaltheus and Oistoceras may be collected in the same bed up to
within fifteen feet of the base of the spinatum zone. This feature
does not seem to occur except around Lincoln, and possibly in North
Lincolnshire, where Ussher! found capricorn ammonites only ten feet
below the Marlstone rock bed (spymatum zone). ‘‘ Amm. striatum”
was recorded at Bracebridge by the Survey, but the ammonite
usually known by this name occurs much lower in the sequence;
the forms found at Lincoln previously included under that name are
the spheerocone stages of Amblycoceras, Oistoceras, and Androgyno-
ceras. It is hoped that these will be described shortly.

The section to be examined at the Albion Brickworks (formerly
Handley’s Pit) one mile north of the Lincoln Cathedral, shows
a faunal succession which does not differ from that seen at Brace-
bridge, but there are some interesting differences in the lithology of
the spunatum zone and the overlying Transition Bed.

SECTION AT THE ALBION BRICKWORKS.

ft. in.
tenuicostatwm Paper shales, weathered red and orange . : . 15 0
sub-zone.
acutum sub- Greenish shale with Tiltoniceras and Dactylioceras
zone, 2ft. 6in. athleticum . eG

Ferruginous sandstone with Dactyloids (D. athieticum,
D. cf. tenuicostatum, D. semicelatum, Coeloceras
ef. fonticulum) . : : : A eatin (0)

1 A. E. Ussher, Geology of North Lincolnshire, ete. (Mem. Geol. Surv.),
1890, p. 49.

A. E. Trueman—The Lias of South Lincolnshire. 105

ft. in.
spinatum Ironstone with phosphatic nodules. Belemmnites,
zone, 22ft.8in. Rhynchonella tetrahedra, Terebratula punctata,
Cincta numismalis, Plewromya costata, Pecten
equwalvis, P. lunularis 10
Light-grey shales with several thin phosphatic nodule
beds. : about 19 0O
Light-grey shales with Amaltheus sp. 4 ‘ 5 abe
Ferruginous limestone with Pecten equivalvis . : 10
Several phosepasie nodule beds 4 5 6 10
margaritatus ~ Shale : : : ‘ » to base 30 0
zone.
Randleys Pir, Lineatn, Brovebridge ac lineata

Toe Margantatum.

Fic. 8.—The Transition Bed and Middle Lias of Lincoln.
(P, level of phosphatic nodule beds.)

Comparing the spinatum zone in the above section with that at
Bracebridge it is seen that the phosphatic nodule beds are not
contemporaneous (Fig. 3), and cannot be used for correlation.
J. H. Cooke,! after examining the section just described, concluded
that the Konmieene limestone which is taken to be near the upper
limit of the margaritatus zone was the Lincoln representative of the
Marlstone of other localities. This was shown to be erroneous by
the Rev. E. Nelson and Mr. H. Preston, who considered that the
upper rock bed was the Marlstone equivalent. It must be noted,
however, that only the lower part of this bed contains spinatum zone
fossils ; the upper part has numerous Dactyloids, a fact which was
apparently overlooked by previous writers. Thus the Lincoln
equivalent of the Marlstone ironstone of the south of the county is
a light-grey shale with abundant phosphatic nodules at varying
levels,

1 J. H. Cooke, GEOL. MaG., Dec. IV, Vol. IV, p. 253, 1897.

106 A. L. Trueman—The Lias of South Lincolnshire.

The Transition Bed (acutwm sub-zone), which has not previously
been definitely proved except in Leicestershire, Northamptonshire,
and Warwickshire, is well developed in the Lincoln district. The
lithology of the lower part varies remarkably, consisting of clay at
Bracebridge and of sand a few miles away, at the Albion works.
‘The upper part, however, in both sections, consists of green shale.
Dactyloids are common throughout (Dactylioceras athleticum, D. cf.
semicelatum, D. cf. tenuicostatum), but the zonal fossil 7. acutum
appears to be confined to the green shale at the top. The Transition
Bed of this district is thus different from that of the Midlands, where
Dactyloids and Ziltoniceras acutum appear together in the lowest bed.
Thus we must either conclude that only the upper portion of the
Transition Bed of Lincoln is homotaxial with the Transition Bed of
the Midlands, or else that 7. acutum did not arrive in the Lincoln
area until later. No indications of a break in sequence are to be
found either at the top or bottom of the Transition Bed. Ifa break
occurred, however, it would possibly be at the base of the green
shale.

Immediately overlying the green shales of the Transition Bed at
Bracebridge is an impersistent dark-grey limestone containing
Posidonomya bronni, succeeded by paper shales with impressions of
compressed ammonites. In places where the limestone is not present
there is a more gradual transition between the shales and the
junction is less easy to define.

In the cliff above the Albion Brick Pit the Upper Lias clays were
formerly worked in Swan’s Pit. This pit is now disused and the
section cannot be fully studied, but is probably as follows :—

CLIFF ABOVE THE ALBION BRICK PIT.

ft. in
Oolitic limestone (Lincolnshire Limestone) : 8x80
Northampton Sands (ferruginous) 4 6
[Yeovilian and part of Whitbian deposits missing—non- sequence. 7]
subcarinatum Well-laminated shales, blue and black, with ferru-

sub-zone. ginous nodules. Fossils rare. Hildoceras bifrons. 40 0
50 ft. Shell bed. Trigonia pulchella, Nucula hanmeri,
Hildoceras, Dactylioceras . 1 4
Shales and shell beds with Dactylioeeras. Frechiella
subcarimata : 8 8
pseudovatum- Shell bed with Lucina 1 6
falevferwm Shale with shell beds and septaria " containing
sub-zones. Harpoceras aft. mnuilgraviwm, Phylloceras cf.
20 ft. 6in. heterophyllum, Nucula, Belemnites subtenwis about 19 0
exaratum Shales, not now exposed . : : ; about 15 0
sub-zone.
tenuicostatum Paper shales . : : ; é : about 15 0
sub-zone.

In constructing the above section use has been made of those given
by Messrs. W. D. Carr! and W. H. Dalton.’

The upper part of the Lias here is not very fossiliferous, but as no
fossils of a higher horizon than Hvldoceras bifrons have been found, it
is probable that there is a non-sequence between the Lias and Oolites,

1 W.D. Carr, Gkou. MaG., Dec. II, Vol. X, p. 164, 1883.
2 W.H. Dalton, Lincoln (Mem. Geol. Sury.), 1881, p. 33.

A. BE. Trueman—The Lias of South Lincolnshire.

the sub-zones from fibulatum upwards being absent.

the conclusion of W. H. Dalton.!

B. Grantham.

107

This supports

It is useful to compare the sections described above with those in

the neighbourhood of Grantham.

The junction with the overlying

ironstone is exposed at the waterworks at Saltersford about one
mile south of Grantham, where an extensive collection of fossils

from the excavations was made by Mr. H. Preston, F.G.S.,
generously placed his notes and specimens at my disposal.
the remainder of the Upper Lias is exposed in Rudd’s

who

Much of
Brick Yard,

several hundred yards west of the railway station, while the Middle
Lias may be seen in the brick-pits at Gonerby. The general section
may thus be taken as follows :—

fibulatum
sub-zone.
223 ft.

subcarinatum
sub-zone.
51 ft.

pseudovatum-
falciferum.
sub-zone.
9 ft. 6 in.

exaratum
sub-zone.
15 ft.

tenuicostatum
sub-zone.
15 ft.
acutum
sub-zone.
spinatum
zone. 35 ft.

Micaceous shale, grey, iron-stained, unfossiliferous
Grey shales with Psewdolioceras cf. lythense,
Porpoceras vortex, P. aff. verticosum, Hildoceras
bifrons, H. hildense, Phylloceras cf. heterophyliwm,
Peronoceras cf. attenuatum. Leda ovum very
abundant in pockets. (=Lower Leda ovum Beds
of Northamptonshire) : ‘
Grey shales with scattered “nodules. "Hildoceras
bifrons, Dactylioceras commune, D. cf. equi-
striatum, D. hollandrei, Celoceras crassum . ;
Dark earthy limestone. Hildoceras bifrons, Dactylio-
ceras commune, Frechiella subcarinata i 5
Grey shale with scattered nodules. Dactyloids
abundantin nodules. In the lower part, Harpoceras
aff. mulgraviunr occurs 6
Oolite Bed. Rubbly ferruginous limestone and clay
with scattered Oolite grains. Many fossils.
Harpoceratoides ovatum, Y. & B., in upper part.
Harpoceras aff. falcifer, H. mulgraviwm, H.
? strangwayst, Dactylioceras gracile, D. acanthus,
Celoceras aff. fonticulwm, Onustus sp., Nucula
hammert
Grey shale with nodules, Harpoceras aff. falcifer,
Dactylioceras spp., Celoceras aff. fonticulum
Grey shales with blue limestone nodules, containing
well-preserved ammonites at all stages of growth.
Al. aff. exaratuin, Hlegantuliceras elegantulum,
Dactylioceras vermis, Inoceramus
Paper shales with flattened nodules ;
insect remains

fish “smile amd

Unknown.
exposed

Marlstone ironstone, with Rhynchonella tetrahedra
and Terebratula punctata j about

Micaceous clay with beds of rubbly ferruginous stone,
yellow sandy layers containing many bivalves, and
large ironstone septaria, Pholadomya ee Cucullea
sp., Paltoplewroceras spp. c

Junction of Middle and Upper Lias not

1 Loe. cit.

ft. in

lei OF

. 20 0

108 A. #. Trueman—The Lias of South Lincolnshire.

ft. in.

margaritatum Grey micaceous shale with ferruginous limestone and
zone. thin bands of septaria. Amaltheus margaritatus,

55 ft. 6 in. Amaltheus levis, Cucullea miinsteri, Pecten calvus 25 0
“Nodule Bed,’’ a bed of ferruginous stone with small

phosphatic nodules é 3 ‘ 6
Dark-blue shale, with scattered septaria. A. mar-

garitatus, Seguenzicer asalgovianum . 2 Aes a0)

The margaritatus zone at Grantham is much thicker than it is near
Lincoln and the ammonites of the Ovstoceras sub-zone do not pass —
into it. A curious feature of the margaritatus zone of Grantham is
the presence of a bed of phosphatic nodules. It has been suggested
that this bed is the equivalent of that seen near Lincoln,’ but
evidently its horizon is very different. Noexposure of the Transition
Bed has been examined in the Grantham neighbourhood, but it may
be seen in the Caythorpe district, about eight miles to the north,
where the following section was measured near the railway bridge,
about a mile south of Caythorpe Church.

ft. in.

tenuicostatum Paper shales with fish scales. ane gee é S20
sub-zone.

2? acutum Ferruginous sand. ¢ : : . : : 4
sub-zone.

spynatum Oolitic ironstone : oe 2 U

zone. Blue-green ironstone weathering to reddish- -yellow,
fossils rare. : F gd oy 30)

South of Grantham the junction of the Middle at Upper Lias may
again be seen near Harby, four hundred yards north-east of White
Lodge.

ft. in.
tenwicostatun. Blue paper shales, Dactylioceras tenwicostatwm, D. cf.
sub-zone. semicelatum, Pseudolioceras sp. Fish scales. balls}.
Cream-coloured limestone with fish teeth and scales . 1
2acutum White limestone with many broken sheils 2
sub-zone.
spunatum Red ironstone, with abundant Rhynchonella and
zone. Terebratula . : é : ; : 5 lOO)

At neither of these places, however, have any ammonites been
found in the beds which are taken to represent the acutwm sub-zone.
It will also be noticed that the Transition Bed thins out as it is
followed southwards through the county; thus it is not in direct
continuation with that of the Midlands. Probably there was
a slight uplift over the greater part of the country after the hemera
of spinatum, several shallow basins being formed, and during the
hemera of acutum sediments only accumulated in these restricted areas,
one of which was around Lincoln but only extended for a few miles
to the south.

One of the most interesting fossils found in the Upper Lias of
Grantham is one which Mr. 8. 8. Buckman has identified as
Harpoceratoides ovatum, Y. & B., indicating the pseudovatum sub-
zone, which had not previously been proved to exist outside

1 H. B. Woodward, Lias of England and Wales (Mem. Geol. Surv.), 1893,
p. 241.

A, E. Trueman—The Lias of South Lincolnshire. 109

Yorkshire.’ The Oolite Bed, in the upper part of which this fossil
was found, probably represents a period of slow deposition.? This
period is similarly represented in Northamptonshire, where it lasted
longer, during the deposition of the subearinatum sub-zone, which is
consequently much thinner than in Lincolnshire.®

Ve

A

TRAMP TCH

RANTHAM|

Lincolnshire, and Northamptonshire

quals 150 feet.)
“ After B. Thompson, Jubilee Vol., Geol. Assoc., 1910.

9

Lincoin
—
ss

(Vertical scale, 1 inch e

Fic. 4.—Middle and Upper Lias of Yorkshire,

AfterS. 8. Buckman, Whitby Memoir, 1915, p. 69.

iH i y WHIT]

2 HH nH H H i TM

rap es ibe] | Ht HH

=) < h ti AH

11) 1 | H Ui il Hh
21) 3 i HH
s|| Hut Hh

palit ee PRY MTT a

E 5 Bee, ee

Siete shes sys Bnei tie ante ate

a Rigi erstin 3 Ea 3 Tah oe at

= os 2 = Fee (aa = Satie

= free = & ee Fel ey RR on Giese

oO = 4 = OD = £ a ea)

<a ose 8 & 2 AS si se Soe Mw

Se Ea tesisl NOP PVPS hous eh Ee ee

1

1S. 8S. Buckman, Geology of Whitby, etc. (Mem. Geol. Surv.), 1915,
pp. 75, 102.

* H. Preston & A. E. Trueman, ‘‘Oolite Grains in the Upper Lias of
Grantham ’’: Naturalist, 1917, 1s Pal

> B. Thompson, Northamptonshire (Jub. Vol. Geol. Assoc.), 1910, p. 462.

110 A. #. Trueman—The LInas of South Lincolnshire.

GENERAL CONSIDERATION oF THE Upprr Lias. (Figs. 4 and 5.)

The variation in the thickness of the Upper Lias in Lincolnshire
has resulted from two movements, viz. :

(1) A series of uplifts along an axis in South Yorkshire at

intervals during the deposition of Lias and later rocks.

(2) The migration of the area of maximum deposition of the

Upper Lias from north to south.

This latter movement was traced by Mr. 8. 8. Buckman,’ who
showed that the zones which are represented by thick deposits in
Yorkshire, are only present as thin layers further south, while later
zones not well developed in Yorkshire are very thick in the south.
This migration of the area of maximum deposition may now be traced
across Lincolnshire; thus the tenwicostatum subcarinatum sub-zones
attain their maximum thickness in Yorkshire, and are fairly thick in
Lincolnshire, but rapidly decrease in thickness towards Northampton-
shire and the south. On the other hand, the fibulatum zone, which
is only thinly represented in Yorkshire, shows increasing thicknesses
at Grantham and Northampton. In this area it is interesting to
notice that the places of minimum deposition in any zone are
characterized by Oolitic beds. It is probable that during the
deposition of the Upper Lias a shallow down fold passed gradually
from Yorkshire southwards, its position determining the area of
maximum deposit at any time.

Lincoln Grantham : ‘Northampton Ste

——s = Pusass
S$uo-zone
= Subearinarum
: Sub- zone.
Fic. 5.—Diagram showing the relationship of the Northampton Sands and
Upper Lias. (Not to scale.) :

Accompanying this movement was one which probably commenced
earlier, that is, an uplift or rather a series of uplifts along an axis
in South Yorkshire. Asa result of this the thickness of the Lias as
a whole decreases as it is traced southwards across Yorkshire or
northwards across Lincolnshire. The Upper Lias also decreases in
thickness in the same way; in Northamptonshire it is about two
hundred feet thick, at Grantham 115 feet, and at Lincoln only one
hundred feet, diminishing still more rapidly further north until at
Appleby? it is usually little more than fifty feet thick. The
thinning, however, is probably not so regular as appears from these
figures, for at Caythorpe, between Grantham and Lincoln, a boring
showed the Upper Lias to be nearly two hundred feet thick,®

1 §. S. Buckman, ‘‘ Certain Jurassic (Lias—Oolite) Strata of South Dorset’’:
Quart. Journ. Geol. Soc., vol. lxvi, p. 88, 1910.

2 Water-Supply of Lincolnshire (Mem. Geol. Sury.), 1904, pp. 33-5.
nee Preston, ‘‘ On a New Boring at Caythorpe’’: Q.J.G.S., vol. lix, p. 29,

R. M. Deeley—Mountain Burlding. 111

although judging from the fossils obtained, no higher sub-zones
were present than usually occur in Lincolnshire. The change in
thickness of the Upper Lias from Lincoln southwards, moreover, is
not due to an increase in the thickness of the component zones, which
vary in thickness as pointed out above, but is due to the greater
extent of the non-sequence at the top of the Lias when traced
northwards across Lincolnshire; thus, while the fibulatum, braunianum,
and Jillc sub-zones are present in Northamptonshire, of these only
the fibulatum sub-zone is definitely represented at Grantham, and
none of them are found at Lincoln. It appears, therefore, that
uplift in South Yorkshire occurred at intervals, namely, during the
deposition of Lower and Middle Lias, and towards the close of
deposition of Upper Lias.

I1I.—Moonvain Boixvine.
By R. M. DEELEY, M.Inst.C.H., V.P.G.S.

(JX\HE structure of mountain ranges has always been difficult to
understand. They often show that peculiarly complicated
disturbances of strata have occurred in the process of their formation.
Mountain ranges in many stages of dissection are to be seen in
various parts of the world; but the better knowledge which their
study has furnished us with has not, at the moment, always assisted
us in the better understanding of the problem of mountain building.

At the present time the compression theory may be said to be the
one most generally accepted. It is thus described by James Geikie: ?
‘‘ Little progress could be made towards a satisfactory theory until
the geoiogical structure or architecture of individual mountain chains
had been studied with precision. Many observations and descriptions
of the folded rocks of the Alps and other regions had been recorded
... but... geology could still present no clear conception of
a mountain range as an organic unity ... it was not until the
appearance in 1848 of the well known essay by Professors W. B.
and H. D. Rogers on the physical structure of the Appalacians, that
geologists generally began to realize what is meant by the architecture
of mountains of elevation. Thanks to the labours of these brilliant
observers and their many successors, we are no longer in doubt as to
the part played by compression in the formation of mountain ranges.”
That compression is the cause of the upheaval of mountain ranges,
and the folded structure they present, James Geikie had no doubt,
and he enforces his argument by pointing to the phenomena of
cleavage, schistosity, etc., as the result of the same action.

To some, however, the amount of compression required to form
a mountain range, not to mention the sharply marked anticlines and
synclines of less elevated regions, seems greater than can be allowed.
To again quote James Geikie,? ‘‘ While overfolding and wholesale
horizontal displacements are the most characteristic features of
Alpine architecture, it must not be forgotten that compression

' Mountains, their Origin, Growth, and Decay, 1913, p. 66.
2 Thid., p. 130.

112 R. M, Deeley—Mowntain Building.

resulted only in the bulging up or general elevation of the great
central massifs, and in diminishing the width of the entire Alpine
area. Many years ago Professor Heim was of opinion that if all the
Alpine folds were smoothed out and the strata regained their original
position, they would necessarily extend over a much wider area;
the two points Ztirich and Como, for example, would be further
apart than they are at present by some 120 to 150 kilometres. But
this estimate he thinks is now much under the mark; according to
him, the Alpine area before compression took place was a flat land
measuring probably 600 to 1,200 kilometres across. Instead of this
broad low-lying tract, we have now a lofty mountain chain averaging
no more than 150 kilometres in width.” He accounts for the com-
pression by adopting the theory that ‘‘The movements referred to
are doubtless due to the wrinkling of the earth’s crust over the
slowly cooling and contracting material ’’.

The above quotations have been made for the purpose of showing
what may be considered to be the attitude of very many geologists
at the present day. However, the theories he advocates he did not
originate, but they certainly appeared to him to be sufficiently well
established to admit of their being placed before the public as sound.

Many physicists who have carefully studied this theory of com-
pression by cooling are quite satisfied that it is not capable of
accounting for the amount of compression required. O. Fisher, for
example, maintains that secular contraction of a solid globe through
mere cooling will not account for the observed phenomena. he idea
is that the already cooled surface of the earth was thrown into folds
as the hotter interior cooled. We must assume, for instance, that
* during the formation of the Alps the compression may have amounted
to 1,200 —150 kilometres, or 1,050 kilometres. To effect this, even
if the whole of the crumpling were concentrated in the Swiss Alpine
region, the earth must have decreased in diameter by about 334
kilometres. Indeed, the contraction that is required in the diameter.
of the earth is very much greater than can possibly be allowed.

Thrust planes have also been regarded as proof of compression.’
J. Geikie remarks: ‘‘ But notable as these rock-movements are,
they cannot compare in extent to the similar translations which have
been recognized in Scandinavia, where in one particular case a massive
sheet, many thousand feet thick, is believed by, some geologists to
have been driven from west to east, for a distance apparently of
80 miles or thereabouts.’’ It is unfortunate that these faults should
have been called ‘“‘ thrust planes’’. It would be impossible to thrust
a sheet of rock over the surface beneath if the proportions of thickness
to distance were anything like those mentioned. A force applied to
one end of such a rock sheet would merely buckle it up for a short
distance. ‘‘Gliding plane’ would be better than ‘‘ thrust plane”
as a name for such phenomena.

In view of the considerations that have been mentioned, it would
be well to consider whether the folding, etc., that is so often exhibited
in mountain chains may not be the result of other agencies.

1 Tbid., p. 173.

R. M. Deeley—Mountain Building. 113

Some experiments recently made by the author of this paper,!
showed that when a heavy viscous layer of sealing-wax loaded with
‘sand rested upon a layer of pitch, the heavy wax sank into the lighter
layer below, in such a manner as to simulate the effects of com-
pression. This point was noticed by Mr. G. W. Lamplugh, who
called my attention to it, and he inquired whether the same con-
ditions could be applied to the folding of mountain chains. If such
were the case the folding would result in local tension, not general
compression.

The experiment above referred to was made for the purpose of
showing that when a heavy bed of sandy gravel, or clay with stones,
rests upon a soft clay or brickearth, if the two deposits were brought
into a viscous condition after frost, then the heavy overlying bed
would settle into the lighter bed below in a manner which would
produce a structure very closely resembling the ‘‘ trail and underplight”’
of Spurrell.

That the crust of the earth is flexible, and that it, therefore, can
sink and rise, as denudation and deposition take place, is now
generally conceded. In the case of the Gangetic trough Oldham,?
though not considering that the trough owes its origin to the weight
of the alluvium, remarks: ‘‘ But though the weight of the sediment
cannot have been the originating cause of the depression of the
Gangetic trough, it may have had considerable influence in deter-
mining the magnitude of its dimensions, for if there had been some
other cause capable of forcing down the level of the crust to a given
depth before the resistance to further movement became equal to the
force, then the addition of a load of alluvium would enable the same
force to lower the level to,a greater extent than if the hollow had
been left empty or only filled with water. The amount of this extra
depression would depend on the balance between the force and the
resistance ; if both remained appreciably constant, within the limits
of the movement involved, the weight of the alluyium would enable
this to be carried about five times further than would otherwise be
the case, so that the Gangetic trough, taken as 15,000 feet deep,
would only have a depth of about 3,000 feet had it not been filled
with alluvium as fast as it was formed.”

The above reasoning is based upon the fact that wherever mountains
occur it has been found that the crust beneath them is of low density
and that the mountains float upon this lighter material. Simwarly,
beneath the deep seas the crust is of high density and the land level
is caused to sink to great depths. As changes in the level of the land
have been numerous, and of great magnitude during geological time,
it is clear that changes in the density of the lower portions of the
earth’s crust are continually but slowly taking place. As long as
such areas of high or low density persist there will continue to be
mountains or deep seas. Denudation alone cannot reduce a mountain

1 R. M. Deeley, ‘‘ Trail and Underplight’’: Grou. MaG., Dec. VI, Vol. III,
pp- 2-5, 1916.
2 “The Structure of the Himalayas’’: Geol. Survey of India, vol. xlii,
pt. ii, p. 122
DECADE VI.—VOL. V.—NO. II. 8

114 R. M. Deeley—Mowntain Burlding.

range; for as long as the rocks below are of low density the mountain
mass will rise as fast as material is removed by denuding influences.

_ The cause of the variations in the density of the deep-seated

portions of the earth’s crust is as yet uncertain; but we are entitled

to regard the crust as floating upon a liquid : stratum of great viscosity,

or a very plastic solid stratum,

It may not be out of place to explain what is here meant by
plasticity and viscosity.

Although it is certain that our present knowledge of the properties
of fluids and solids, from the physical point of view, is by no means
complete, it will not be out of place to consider some of the very
complex phenomena they exhibit, and which have a bearing upon
geological problems. The subject is, indeed, one of, very great
importance to the engineer and physicist, for to the former the
physical properties of solids have to be considered as far as they affect
the stability of all kinds of structures, whilst in the case of the
latter they have to be borne in mind when dealing with the question
of the stability of mountain ranges, etc.

One very frequently hears semifluids spoken of, and there are
many who are of opinion that there is a regular transition of the
solid into the liquid state, or that there are a large number of
substances which can be arranged in such an order that they show
a transition from the solid to the liquid state. The idea that
liquidity is only a matter of degree was well expressed by Tyndall,’
who writes: ‘‘ What was the physical condition of the rock when
it was thus bent and folded like a pliant mass? Was it necessarily
sotter than it is at present? I do not think so. The shock which
would crush a railway carriage, if communicated at once, is harmless
when distributed over the interval necessary for the pushing in of the
buffer. By suddenly stopping a cock from which water flows you
may burst the conveyance pipe, while a slow turning on of the cock
keeps all safe.”’ All this is more plausible than sound. He then
goes on: ‘‘ Might not a solid rock by ages of pressure be folded as
above? It isa physical axiom that no body is perfectly hard,*none
perfectly soft, none perfectly elastic. The hardest body subjected to
pressure yields, however little, and the same body when the pressure
is removed cannot return to its original form. If it did not yield in
the slightest degree it would be perfectly hard; if it could completely
return to its original shape it would be perfectly elastic.”’

‘Tet a pound weight be placed upon a cube of granite; the cube
is flattened, though in an infinitesimal degree. Let the weight be
removed, the cube remains a little flattened ; it cannot quite return
to its primitive condition. Let us call the cube thus flattened No. 1.
Starting with No. 1 as a new mass, let the pound weight be laid
upon it; the mass yields, and on removing the weight it cannot
return to the dimensions of No. 1; we have “¢ more flattened mass,
No. 2. Proceeding in this manner, it is manifest that by a repetition
of the process we should produce a series of masses, each succeeding
one more flattened than the former. This appears to be a necessary
consequence of the physical axiom referred to above.

1 Glaciers of the Alps, 1860, p. 9.

R. M. Deeley—Mountain Building. 115

** Now, if instead of removing and replacing the weight in the
manner supposed, we cause it to rest continuously on the cube, the
flattening, which above was intermittent, will be continuous; no
matter how hard the cube may be, there will be a gradual yielding
of its mass under pressure.’

Since the above was written a great deal of additional information
has been obtained experimentally ; but very few attempts have been
made to put this in a form which would be useful to the geologist,
or eyen to the engineer who has not made a special study of the
subject; and one may say with truth that although Tyndall’s state-
ment now seems very far from being a complete or even correct one,
many modern writers seem to base their geological theories upon
some such theory of the solid and liquid states.

From the scientific point of view there is every reason to believe
that the solid and liquid conditions of matter must be regarded as
quite distinct physically, and that when the one state passes into the
other the change is abrupt.

In the case of a liquid, if it be placed in a hollow cup-shaped
vessel it will be found that the upper surface is a perfectly level one.
Water, for example, after a few oscillations, settles down quickly.
A thick lubricating oil does so more slowly; but pitch may take
weeks or even years to reach the perfectly horizontal position.
There is no question but that all liquids, under such conditions, flow
until their upper surfaces are quite horizontal, and in this respect
they are all true liquids but differ in viscosity. In every portion of
the mass the stresses eventually become equal and opposite.

If small boats be placed on these liquids, in the case of oil and ~
water they will quickly sink until they have displaced their weight
of oil or water. In the case of the pitch, a similar boat, when first
placed on the surface, will rest there, but it will slowly sink into the
pitch until it also floats and displaces exactly its own weight of pitch.
Oil, water, and pitch are all perfect liquids, but pitch is more
viscous than oil, and oil is more viscous than water. At the same
temperature and pressure the fluidity (viscosity) is always the same
in the case of liquids possessing definite chemical compositions, and
may be expressed in terms of some particular unit such as Poise,
which is a C.G.S. scale.

A solid may be either hard or soft, but however soft it may be it is
not aliquid. Thus, if we had a very large vessel partly full of soft
clay (a material much softer than pitch), its upper surface would
never become quite flat. Ifa heavy boat were placed upon the soft
clay the boat would sink some distance into it, but it would never
sink until it displaced an equal weight of clay. Indeed, it would
sink to a certain distance into the clay quite rapidly, and would then
come practically to a standstill. However, it might go on con-
tinuously sinking slowly and yet never displace its weight of clay.
This may be illustrated in the following way: Imagine that the rate
at which it sinks gets slower andslower. Take it that in the first hour
it sinks half a yard. In the next hour it sinks one-quarter of a yard,
in the next one-eighth of a yard, and so on. At this rate it will
always be sinking, but will never sink more than one yard. Tyndall’s

116 R. M. Deeley—Mountarin Burlding.

cube would déform in some such way as this, and the deformation
would never become appreciable.

However, if a soft solid have too great a weight placed upon it, it
will yield continuously much as will a liquid. In extruding lead
through a hole in a cylinder no movement takes place until a certain
pressure is reached; the lead then flows out through the hole and
flows faster as the pressure 1s increased.

Now the upper portion of the earth’s surface is composed of rocks
varying in hardness. Buildings may be erected upon it which will
be permanently stable, provided the load on their foundations is not
too great. ‘The load per square foot that may with safety be placed
upon each kind of rock varies considerably, and it is the engineer’s
endeavour to find out what is the smallest area and depth of founda-
tion that will ensure stability in each case, so as to keep the cost of
the building as low as possible.

The load-carrying capacity of any kind of rock varies much
according to surrounding conditions. Dry clay will carry more than
wet clay. On this account the water escaping from a burst water-
pipe may so soften the clay or marl upon which a building rests
that the foundations give way. Vibrations caused by heavy vehicles
have the same effect. Railway bridges and retaining walls have
to be made much stronger, for the same loads, than have road bridges.
and walls. No doubt the foundations of St. Paul’s Cathedral were,
in most instances, amply sufficient under the conditions existing
when Wren built it, but the vibrations resulting from the heavy
road and rail traffic of our times, and the effects upon the local
drainage produced by sewers, etc., have much interfered with their
stability.

The nature of the resistance to stress offered by the materials.
forming the earth’s crust is in some cases of a liquid and in others of
a plastic description. The liquids, whether water or molten rock,
settle down with their upper surface layers practically horizontal ;
but owing to their varying density and the plastic resistance they
offer to flow, the solid rocks stand at various levels. We thus have
large raised areas floating upon ‘‘roots” of light material and
depressed areas over roots of heavy material, the whole floating upon
a plastic or liquid substratum. It has been suggested that this.
substratum rests upon harder material, and it has been called the
asthenosphere. But the raised areas are not necessarily quite stable.
The materials of which they are built up are being denuded and
carried to lower levels, with the result that the area rises to restore
the balance, and the areas over which deposition takes place sink for
the same reason.

The flexing of the earth’s crust by the moon results in ‘‘ earth
tides”, and these, together with earthquake shocks, have the same
effect upon the stability of mountain masses as have the vibrations.
produced by heavy traffic upon the foundations of St. Paul’s
Cathedral. Elevated areas consequently tend to flow and spread
outwards over the surrounding lower lands, or to slide under the
action of gravity bodily into depressions. Such sheets of rock are not.
pushed along by pressure applied at one end; they slide bodily down

R. M. Deeley—Mountarin Building. TAL

a slope under the action of gravity, every yard of the mass furnishing ©
its own propulsive force.

How the dense ‘‘roots’’? of depressed areas and the lighter
‘roots’? of elevated areas arise, it 1s not my intention to discuss.
That such roots exist a perusal of the paper by R. D. Oldham
already referred to will demonstrate.

Rain, rivers, etc., attack the elevated areas, cutting out river
valleys of varying width. The character of the resulting scenery
depends upon the nature and hardness of the rocks. The depth and
width of the valleys resulting from denudation must bear a close
relationship. to the forces required to make the rocks flow. When
the rocks are soft and erosion results in the production of deep
valleys, then the valley bottoms rise, the sides close in, and various
irregularities in the bedding planes result. In this way anticlines
and synclines are very frequently formed zzthout lateral pressure.
Such movements are greatly assisted by temperatures.

The crust of the earth grows warmer and warmer as the depth
increases. This gradient of temperature in the crust is about 1° F.
for every 70 feet of descent. At great depths the rocks are con-
sequently very hot. Now a solid almost always becomes softer and
softer as the temperature is raised, and the force which will cause
it to flow becomes smaller and smaller. If the temperature were
raised so high that the force which would produce continuous flow
fell to almost zero, then the solid would have been abruptly turned
into a liquid, and flow would result however small the force might be.

When a plastic substance is distorted microscopic examination
shows that it has resulted from the formation of many distinct shear
planes. On the other hand, the distortion of a viscous substance is
caused by shear between planes whose thicknesses are of molecular
dimensions.

A piece of granite overloaded would break into small fragments.
It would not flow like soft clay. However, if the granite were
surrounded by some substance under very great pressure, then the
particles of rock would be so firmly held together that it would not
fracture if deformed; but would change its shape without breaking.
It thus comes about that although hard rocks are fractured by earth
movements near the earth’s surface, they remain massive at great
depths although they suffer distortion. This ability of rocks at great
depths to suffer distortion without fracture is, of course, much
assisted by the high temperature prevailing there.

The idea that the surface rocks are floating in very many places
upon a fluid stratum can be shown to be probable by many
phenomena. During Tertiary times, over an area of some 200,000
square miles of what is now Idaho, Oregon, and Washington, fluid
basic lavas welled up more or less steadily through great fissures,
and covered the whole country with sheets of lava aggregating in
places 2,000 feet or more in thickness. In India a like area was
covered to a depth of from 4,000 to 6,000 feet, while over the Lake
Superior basin and some of the surrounding areas the thickness
reached by more ancient lava floods was from 15,000 to 25,000 feet.
There are amongst these lavas very few beds of ash or cinders, so

118 R. M. Deeley—Mountarin Building.

that the eruption or welling up of these enormous volumes of lava
was not of a violent character. There are many cases also where
~ huge blocks of country, bounded by faults, have subsided, and the
liquid magma below has issued along the fault lines.

We must, therefore, take it that large areas of the earth’s surface
have been, and probably now are, really resting upon a substratum
of liquid or nearly liquid rock, and that in many cases the cooler and
heavier surface rocks have subsided bodily, the liquid rising through
great fissures and spreading over them as they sink. Here there are
no signs of compression ; rather has the crust been stretched to form
the fissures through which the lava welled up.

No ordinary amount of compression could give rise to a mountain
range; for as the rocks thickened locally under the compressive
forces, their weight would cause them to sink, and depression might
result rather than elevation. It has been suggested that the heating
up is caused by compression. However, in the case of North
America, where the vast quantities of basic lava welled up, the rocks
are generally horizontal and show no signs of compression. All that
can be made out is that mountain chains seem to have risen in areas
which have been ones of active recent deposition, and do not appear
to have formed in areas covered by rocks of great age. All our great
modern mountain ranges were raised in Tertiary times over areas of
recent deposition. —

It is probable that our anticlines and synclines are generally the
result of the irregular sinking of the earth’s surface where it rests
upon fluid or very plastic magmas. The syncline of the Thames
Valley, for example, would seem to have varied from time to time,
sometimes becoming more pronounced and then flattening out again.

The view that rocks of varying density resting upon a liquid
substratum may produce synclines and anticlines has already been
suggested by Coleman.1 He says: ‘‘Some years ago I ventured
another explanation. Granite is specifically lighter than most of the
greenstones and schists of the Kewatin; and molten granite, even if
not at avery high temperature, is lighter than the relatively cold
rocks above it. If the rocks above were unequally struck, so that
some areas were less burdened than others, it is conceivable that
these differences in gravity might cause the granite to creep slowly
up beneath the parts with lightest loads, whilst overlying rocks
sagged into synclines in the heavily loaded parts.”

‘‘ Whatever the cause, these batholiths enclosed by meshes of
schist are the most constant feature of the Canadian Archean,
though in many places erosion has cut so deeply that the meshes
have all but disappeared, leaving only straight or curving bands of
hornblende schists enclosed in Laurentian gneiss.’’

Here we appear to have a mountain mass so deeply dissected by
denudation that the cause of the existence of the anticlines and
synclines which no doubt characterized the ranges is disclosed. The
folds were not formed by lateral pressure, but by the stretching of
the beds of rock as some portions settled down and others rose.

1 Presidential Address, Brit. Ass. Rep., 1910, p. 54.

R. M. Deeley—Mountarin Building. 119

However, the bending of the rock stratum, although resulting in
a general stretching, would also produce local compression. That
a mountain range may be resting upon a liquid or very plastic base,
as would appear to have been the case with the old mountain range
the ‘‘roots” of which are now the Canadian shield, leads to some
important consequences.

My chief endeavour has been to show that there are other ways
of accounting for anticlines and synclines than by compression.
To further illustrate the suggestion some remarks will be made
concerning the history of the Swiss Alps.

The structure of the Swiss Alps was for many years an enigma ;
but there seems every reason to believe that the broad outlines of
their architecture are now known.

At the base we have crystalline gneisses, schists, and granites.
They form the lofty massifs of Mont Blanc, the Aiguilles Ronglies,
the Bernese and Gothard Alps, etc. They once formed a highly
worn or much denuded surface, upon which the newer rocks were
deposited. The older rocks are chiefly crystalline masses and some
Carboniferous strata, while the overlying bedded series range in age
from Permian and Triassic down to early Cainozoic. These sediments
filled up the valleys and submerged the mountains of the old land.
The area over which they were deposited was a subsiding one. We
are told that after the deposition of these sediments the sea bottom
was raised and a low flat undulating land area was formed ; and that
great rock-sheets from the north and south were then thrust up
gentle inclines over this land. The chief of these sheets are the
Helvetian, Lepontine, East-Alpine, and South-Alpine. That these
sheets could have been thrust up and over each other and over a
rising land seems quite impossible. That they are there, and have
travelled great distances, is certain; but the conditions under which
they have travelled require further elucidation.

It may be that the sea in which these early sediments were
deposited became very deep, and that the rock-sheets slowly slid into
this deep sea one after the other; for in most instances the upper
sheets are formed of older rocks than the lower ones. The covering
of the sea bed by cold rock-sheets instead of water would deepen the
sea, whilst the removal from the shallow water or land of the cold
rock-sheets would be replaced by rising warmer rock. This would
increase the gradient and result in further slides.

The whole mass was then raised and folded. It is very doubtful
if this folding was the result of pressure: rather may it have been
due to the differential vertical earth movements resulting from
denudation. During the rising of the Alps great deposits were
formed along the margins of the mountains. It is a peculiar fact
that some of the rock folds have moved outwards and been thrown
over these deposits. Indeed, it may be that overfolds are not due to
thrust; but are due to the flow of the elevated rocks near the margins
of the mountains towards or even over the surrounding low lands.

It is rather a rash thing perhaps to suggest that compression has
not been a prime factor in earth movements; but the difficulties that
can be urged against the idea are so very great, that it cannot be

120 Dr. BR. L. Sherlock—Datwm-lines in English Kewper.

considered more than a working hypothesis until the physical
difficulties are met. If it can be shown that compression is not
required, and that the phenomena of folded mountain chains can be
otherwise explained, a distinct advance would be made in dynamical
geology.

TV.—Darum-tines In THE EnciisH KEvrrr.
By R. L. SHeRLocK, D.Sc., A.R.C.Sc., F.G.S.

N the almost complete absence of fossils in the British Keuper
there has been a lack of datum-lines in that formation by which
we may compare the horizons of different sections. Yet in such
a thick and widely spread deposit it 1s very desirable to have sub-
divisions enabling us to give the particular part of the Keuper to
which a section belongs. In deposits such as the New Red
formations too great stress has been laid on lithology, inevitable
perhaps in the scarcity of fossils, but a source of grave errors in
correlation. For example, Mr. L. J. Wills! thinks that fossils found
in the Keuper of Warwick have affinity, not with the Keuper, but
with the Muschelkalk of Germany. Again, there are strata in the
Permo-Bunter of Nottinghamshire* which might be mistaken for
Keuper Waterstones, if only lithology was considered. Over small
areas a band of sandstone with some peculiarities may be used as
a datum-line, as in the Arden district of Warwickshire* and in
Nottinghamshire,* but these are of local value only.

Recently Mr. Bernard Smith and myself have had occasion to visit
all places where gypsum is worked, or likely to be workable,
throughout England, and it appears that the workable deposits of
gypsum within the Keuper occur at definite horizons. The economic
results have been published in a recent memoir,® but I wish here to
show that they give us two definite horizons, the upper one found at
intervals between North Yorkshire and Somerset and the other over
parts of three Midland counties. “Using these datum-lines, I propose
to show that they help us to state the nature of the Keuper- Rheetic
junction and to determine whether or not the Tea-green Marls oceur
at a definite horizon.

1. Lhe Upper Horizon.—Four beds of gypsum occur in a definite
order in the quarries and mines situated between Beacon Hill
(Newark) and Orston, to the south-west, a distance of 95 miles. In
the figure sections are given of the strata found at Newark, Hawton,
Bowbridge, and Orston. Those at Newark, Bowbridge, and Orston

1 “On the Fossiliferous Lower Keuper Rocks of Worcestershire’’: Proce.
Geol. Assoc., vol. xxi, p. 268, 1910.

2, R. L. Sherlock, ‘‘ The Relationship of the Permian to the Triag in
Nottinghamshire ”’ : Quart. Journ. Geol. Soc., vol. Ixvii, p. 82, 1911.

3. A. Matley, ‘‘The Upper Keuper (or Arden) Sandstone Group and
Associated Rocks of Warwickshire’’: Quart. Journ. Geol. Soc., vol. lxviil,
pp. 252-80, 1912.

11835 Smith, ‘“The Upper Keuper Sandstones of Hast Nottinghamshire ”’ :
GEOL. MaAG., 1910, pp. 302-11.

> R. L. Sherlock & B. Smith, Special Reports on the Mineral Resources of
Great Britain (Mem. Geol. Sury.), vol. iii, ‘‘ Gypsum and Anhydrite,’’ 1915.

Dr. R. L. Sherlock—Datum-lines in English Keuper. 121

have already been published.’ The two latter mines and quarries
belong to The Vale of Belvoir and Newark Plaster Company, the
others to Messrs. Cofferata & Co., and my thanks are due to these
two firms for the kindness with which they have allowed me to visit
the sections, and for information. The distance from Beacon Hill,
Newark, to Hawton is about 2 miles; Hawton and Bowbridge are
only separated by some 350 yards, Bowbridge lies slightly to the
east of Hawton, and in consequence of the easterly dip higher beds
are visible at Bowbridge than at Hawton. From Bowbridge to
Orston is about 7 miles. The Orston mine was at the time (1915)
disused and the details of the section were given by the proprietor.
Except at Orston the seams of gypsum are visible throughout the
extensive sections (the Hawton quarry is about 700 yards long), and
occur in the same order and at approximately the same distance
apart, and there.is no doubt that they are definitely bedded deposits.
Additional evidence of this is furnished by the fact that some of the
accompanying beds can be correlated in different sections. Thus, the
‘Riders’ (see Sections, p. 122), a nodular band of gypsum resembling
a line of flints in chalk, occurs between the Top and Middle White
Rocks, at Newark, at Hawton, and at Bowbridge; while the
‘‘Bastard”’, a 3 ft. band of mixed green marl and gypsum, occurs
7 feet above the Top White Rock at the same three localities.

At Beacon Hill, Newark, some 664 feet of strata intervene
between the Top White Rock and the base of the Rhetic beds.’ At
Bowbridge there are 45 feet of strata exposed above the rock, and, in
addition, a certain amount crops out under alluvium between the
section and the Rheetic escarpment. At the constant dip prevalent
over the district there is room for about 20 feet of strata in this gap,
giving approximately 65 feet of strata up to the Rhetic base, or
practically the same as at Newark, 2 miles away. At Orston there
is recorded 39 feet of strata above the Top White Rock. Un-
fortunately the section cannot now be seen, and the exact thickness
of strata cropping out between it and the Rhetic base, cut through
in the railway about 20 yards away, cannot be measured exactly.
It would appear that the total thickness of strata between the Top
White Rock and the Rhetic is a few feet less at Orston than at
Newark.

This evidence shows that between Newark and Orston the Rhetic
is separated from the Top White Rock by a belt of strata of
practically constant thickness. In the absence of complete sections
it cannot be said that the thickness of the intervening strata is
absolutely constant, but it can be said that throughout the distance
of 93 miles the variation is not more than a few feet and may be
quite absent, and that over a distance of 2 miles there is no variation
whatever. Hxact correspondence in thickness of the marl beds in
any two sections is not to be expected, as we may see from the
sections figured, and any small differences in the thicknesses of the
intermediate strata are more likely to be due to variation (and cancel
themselves out) than to an unconformity, however slight, of the

1 A. J. Jukes-Browne, Geology of the South-West part of Lincolnshire
(Mem. Geol. Surv.), 1885, p. 18.

&

122 Dr. R. L. Sherlock—Datum-lines in English Keuper.

Rhetic. Hence we may conclude that in this district the Rhetic is
strictly conformable to the Keuper.

Away from the Newark-—Orston district we cannot trace the
individual beds of gypsum. We do find, however, that a belt of
strata containing beds of gypsum occurs at approximately a constant
distance below the Rheetic beds at numerous places between Middles-
brough and Somerset. The gypsiferous belt is of varying thickness,
being better developed in some places than in others, and we cannot

NEWARK HAWTON, BOWBRIDGE ORSTON
Aliuvrtum

wilh Fed
GYPSUM

Marl wil L
earse
Alluvum few cakes GYPSUM PRE |
Marl with of GYPSUM Marwith\o ;
GyPSUM Balls of | 2
Grey eRe __--— -— Grey GYPSUM |S 5
-=5520_ Fock : rock
astard? ~~ cee ere ipo Sarl wilh 2
imuxedgreen marlkgyp _ bastard _ Balk of
ae 5 Titec Marl with Ked GYR
GYPSUM «ee GYPSUM Marl with
fe e ‘cakes’ Balk of GYPSY
Sopwtite rn = = SSSSllit SRW Fock
ee eee Ballsof GIP
TMUGION EN AP STi a eo all of GYPSY
TMI TOOCEEESY. ~~ a “tego white Fock
2D O>| Btue tock ~~ - ely
Ae we toch
Bottant while rock Bue
Marl with Bottom while ro
GYPSUM ao
Blue rock
Marl

Sections in the Newark District of Nottinghamshire.
Scale : 1 inch represents 18 feet.

pick out a particular seam as a datum-line over a large area. But
the belt as a whole may be so treated, if its approximate middle be
taken. North of Newark the belt becomes more poorly developed,’
but it has been worked in the past at Laughterton, near Gainsborough ;
at Winton, Stank Grange, Hallikeld, and Little Sessay, near
Northallerton; and at Eston, near Middlesbrough. Proceeding in
the opposite direction, it is worked at Cropweli Bishop, Notts. In

Dr. B. L. Sherlock—Datum-lines in English Keuper. 128

Leicestershire the gypsiferous belt is seen at Thurmaston Brickyard
and at Gipsy Lane Brickyard,’ Leicester; but between Cropwell
Bishop and ‘Tutbury in Staffordshire the lower horizon of gypsum (to
be mentioned later on) is economically the more important one.
Near Penarth, in Glamorgan, near Yate, in Gloucestershire, and
near Watchet, in Somerset, the upper horizon is being, or has been,
worked.

It is remarkable that although on the west side of Watchet
gypsum is abundant enough to be quarried, at St. Audries,” on the
east side of Watchet, it is quite absent. Buta band of indurated marl,
4 to 6 inches thick, occurs containing celestine, at a depth of 69 feet
below the base of the Rhetic, i.e. at the horizon of the gypsum.
At Yate, in Gloucestershire, the celestine deposits occur at the same
horizon as the gypsum, but only in one place have the two minerals
been found together. We may therefore infer that at St. Audries
the absence of gypsum is due to the presence of celestine at the same
horizon. :

2. The lower horizon of gypsum is worked extensively in the
Gotham district of Nottinghamshire and in East Staffordshire.
A bed of gypsum, usually from 7 to 11 feet in thickness, is worked at
Gotham, Hast Leake, Barton, Thrumpton, and Kingston-upon-Soar,
all in Nottinghamshire, and the gypsum of Chellaston, Derbyshire,
probably belongs to this horizon. In Staffordshire the bed is from
8 to 15 feet in thickness, and is worked in the parishes of Hanbury
and Draycott. The bed is characterized by a ball-like structure on
a large scale, the thicker parts of the seam representing more or less
distinctly the sphzeroids, and the thinner parts the intervals between
them. ‘In thickness and spheroidal structure the bed is fairly well
marked off from other beds of gypsum in the Keuper.

At Kast Leake the gypsum is said to occur about 150 feet below the
Tea-green Marls. This is but a rough estimate, and the thickness of
Tea-green Marls is not stated. The Tea-green Marls vary a good
deal in thickness, but at Newark, where they are best seen, there is
about 18 feet of them. This would give roughly 168 feet of strata
between the gypsum and the Rhetic beds. At Glebe Mine, Gotham,
the details of a ventilating shaft have been preserved,*® and show
a thickness of 160 feet between the gypsum and the Rheetic beds.
At a depth of 86 feet below the Rheetic a thick bed of gypsum was
found, and this is probably part of the upper belt. At Fauld, near
Tutbury, Staffordshire, the gypsum is thought to be about 145 feet
below the top of the Keuper Marl. The discrepancy between the
depth here and at Gotham may be due to various causes, but a likely
one is that, as Rheetic beds were not separated from Lias when the
district was mapped, about 1852, it is probable that the Tea-green
Marls have been put with them in the Lias, in accordance with the
then current idea that the green marls were part of the Rhetic. If

1 For full section see T. O. Bosworth, The Keuper Marls around Charnwood,
Leicester, 1913, p. 117.

2 Vertical sections, Geol. Surv., Sheet 47, No. 6.

* Special Reports on the Mineral Sources of Great Britain (Mem. Geol.
Sury.), vol. iii, p. 26, 1915.

124 Dr. R. L. Sherlock—Datum-lines in English Kewper.

so, the depth of the gypsum below the Rhetic might be much the
same as at Gotham. In Warwickshire gypsum occurs at Spernall
Park, 75 miles north-west of Stratford-upon-Avon, at about 150 to
160 feet below the Rhetic beds, but not in workable quantities.
Owing te the scarcity of measured sections we cannot be certain that
this second horizon occurs at a constant depth below the top of the
Keuper—it is only probable.

The question of the mode of origin of gypsum is a he one and
cannot be gone into here. It suffices that the gypsiferous deposits
we are dealing with are clearly, in the main, primary strata, although
secondary gypsum is also present, and the deposits represent some
special condition, occurring at a definite period over a wide area and
therefore of chronological value.

The occurrence of these two belts of gypsiferous strata at
approximately constant depths below the Rhetic beds points
strongly to the conformability of the Rheetic to the Keuper. The
sharp line of demarcation between them is therefore no more than
the result of the waves of the open sea entering the Caspian-like
sea in which the Keuper was deposited and washing up the
Keuper mud.

The highest beds of the Keuper are the Tea-green Marls, at one
time considered to be part of the Rhetic beds. If the Rhetic were
unconformable to the Keuper it would follow that the Tea-green Marls
occurred at varying positions in the Keuper Series, and it would be
highly probable that the green colour is the result of alteration of
red beds by secondary changes. But if, as the evidence given above
seems to show, the Rhetic is conformable to the Keuper, then the
Tea-green Marls everywhere occur at about the same horizon, so far
as the upper boundary is concerned, and there is a probability that
their colour is original. The green.strata, however, vary greatly in
thickness, for instance at Colston Bassett, Nottinghamshire,’ they
are only about 15 feet thick, whereas near Watchet * they are 115 feet
in thickness. Also the base is often indefinite, sometimes dying out
downwards raggedly, sometimes ending in alternate beds of green
and red marl. Hence, the top being fixed, the base must occur at
somewhat different horizons in different places.

One result of the wide variations in thickness of the Tea-green
Marls is that the higher gypsum horizon is sometimes below it, in
red strata, as in Nottinghamshire, and sometimes well within the
green beds, as at Watchet. It appears that the conditions of
formation of green marl were neither inimical nor helpful to the
formation of gypsum.

The green strata seem to indicate the coming of the open-sea
conditions. The occasional presence of fossilssuch as Ostrea bristovt,
tichardson, recorded by Mr. L. Richardson,® indicates a change in

‘ B. Smith in Geology of the Melton Mowbray District and South-East
Nottinghamshire (Mem. Geol. Surv.), 1909, p. 16.

“ L. Richardson, ‘‘ The Rhetic and Contiguous Deposits of West, Mid, and
part of Hast Somerset”: Quart. Journ. Geol. Soc., vol. lxvii, pp. 19-20, 1911.
* L. Richardson, ‘‘ The Rheetic and Contiguous Deposits of Glamorganshire’’

Quart. Journ. Geol. Soc., vol. lxi, p. 399, 1905.

Dr, A. Morley Davies—On Isostasy. 125

the water, perhaps due to the washing in at spring-tides of waves
from the open sea, now almost ready to break into the landlocked
area in which the Keuper Marl was formed. It is interesting to
note that, north of Nottingham, Tea-green strata also occur, at the
bottom of the Keuper, unconformable to the Bunter below, and
perhaps representing the Jast traces of brackish water before the area
was finally cut off from the open sea.

V.—A. Nore ow Isosrasy.
By A. Morey Davies, A.R.C.S., D.Sc., F.G.S., Imperial College of Science
and Technology.

f{\HERE is a regrettable tendency to looseness of thought among

geologists on the subject of isostasy. I give no quotations in
support of this assertion, firstly because, being always in the form of
casual allusions to the principle, they would require long hunting
down; and secondly because, if given, they would fasten upon a few
individual geologists a criticism which: should be more general.
The usual form in which the looseness of thought shows itself is in
explanations of shallow-water deposits of thickness greater than
their depth of accumulation. We are frequently told that such
thick deposits result from local subsidence due to the loading of the
sea-floor by the great weight of sediment, and reference is made to
the principle of isostasy as justifying this explanation.

The principle of isostasy is that the distribution of mass in
a heterogeneous earth tends to be so adjusted that variations of the
surface from the theoretical ellipsoid of rotation are compensated by
differences of density in the deeper parts of the underlying crust.
The continents are supported on a mass of less density, the oceans on
a mass of greater density; and similarly for the mountain-chains and
ocean-troughs in relation to the average of the continents and oceans
respectively.

This compensation of excess of matter at the surface by defect of
density below and of defect at the surface by excess of density
below is termed isostatic compensation, and the adjustment of the
earth’s crust towards a condition of isostatic equilibrium caused by
gravitative stress is termed isostatic adjustment. Compensation is
supposed to be complete within a comparatively shallow depth
(122 kilometres according to the later calculations of the United
States Coast and Geodetic Survey), and the mass of matter under
any protuberant or depressed area from sea-level down to this depth
is termed the supporting column of that area.

Now imagine the adjacent parts of an ocean and continent, in
perfect isostatic equilibrium. Denudation removes material from
the continent, which is deposited on the ocean bottom. Isostasy is
disturbed, and if isostatic adjustment takes place the tendency will
be for the continent to rise, the sea-floor to sink, and material in the
depths to ‘‘ flow ”’ from the supporting column of the ocean into that
of the continent. But how far can these movements go? ‘The
oceanic supporting column is composed, ex hypothes?, of material of
more than average density; the material deposited, being uncon-
solidated sediment, is of less than average density. The former we

126 Dr. A. Morley Davies—On Tsostasy.

may estimate to have a density of 3. As to the latter, the average
density of sedimentary material (making no allowance for porosity)
is 2°7. Porosity to the extent of 20 per cent brings the density of
unconsolidated dry sediment to about 2°16 (Indian geologists give
2°2 as the average for the Siwalik rocks, so 2°16 is not too low for
quite unconsolidated material). But we have to deal with sediment
saturated with sea-water to the extent of the 20 per cent of its
volume allowed for porosity; this brings the density up to 2°36.
The sediment, however, displaces sea-water as it accumulates, and
though it thereby raises the sea-level, that rise, being distributed
over the whole ocean, is negligible. The effective density for the
calculation of isostatic overloading is therefore 1°36.

A mass of sediment on the sea-bottom, then, would depress the
latter to the extent of 1, or about nine-twentieths of its own
thickness, ¢f the isostatic adjustment 1s perfect and immediate. Thus
at whatever depth deposition begins a thickness equal to ar
or about 1:83 times that depth, could accumulate before the sea was
completely silted up. Taking the 100-fathom line as the limit
between deep and shallow water, shallow-water deposits could
accumulate, under conditions of the most delicate isostatic adjust-
ment, to a thickness of only about 1,100 feet before accumulation
became inter-tidal or subaérial in character, and in that thickness
there would be a gradual transition from deposits of 100-fathom type
at the bottom to littoral deposits at the top. If we suppose the
isostatic adjustment to be spasmodic instead of continuous, there will
be an alternating character in the sediments instead of a gradual
transition, but the total thickness will be, if anything, diminished,
since the adjustment will be less perfect.

It may be objected that 8 is too high a figure for the density of
the supporting column. If we take it at so improbably low a figure
as 2°7, the maximum possible thickness is only increased from 1,100
to just over 1,200 feet.

But what right have we to assume such delicate isostatic adjustment
as these calculations imply? The theory of isostasy originated in
America, where the careful investigations of Hayford and the United
States Coast and Geodetic Survey showed that there is an approxima-
tion to isostatic equilibrium—or, at least, that there is such on a
certain assumption as to the depth of compensation. When Crosfield
investigated India on the same assumption he found that country to
diverge considerably from isostatic equilibrium. ‘This was naturally
explained by the immense crustal disturbances in that region, which,
reaching a maximum in the Miocene period, have not yet entirely
died out. If these great disturbances have not been capable of full
isostatic adjustment in the long period of time that has elapsed
since the Miocene period, can we justifiably assume that the gentle
accumulation of sediment is continually and immediately adjusted ?

Without venturing into any discussion of the complicated subject
of the rigidity of the earth’s crust, I may call.attention to the view
of Professor Barrell that the strength of the crust is ‘‘twenty, fifty,

Notices of Memoirs—A Hycena-den in Ireland. 127

or even a hundred times greater than that advanced in recent years
by the champions of high isostasy”’.' If this opinion, the result of
very careful mathematical studies, be put aside as a pendulum-
swing in the opposite direction to that of the isostasy enthusiasts,
the adoption of a mean position would still diminish our belief in
the possibility of explaining great thicknesses of shallow-water
deposits by the sole process of isostatic adjustment.

NOTICHS OF MEMOTRS.

Se
1.—A Hyawa-pen in [RELAND.

Tue Expnoration oF Casrnepook Cave, Counry Cork: BEING THE
Turrp Report FROM THE COMMITTEE APPOINTED TO EXPLORE
Trish Caves. By R. F. Scuarrr, H. J. Srymour, and KH. TY.
Newton. Proc. Roy. Irish Acad., vol. xxxiv, sect. B, No. 3,
pp. 33-72, pls. v—vii, January, 1918.

HE last work of the accomplished and enthusiastic Irish cave-
explorer, the late Mr. R. J. Ussher, was the careful examination
of the Castlepook cave, co. Cork, which is of much interest as being
further south than any cave previously dealt with in Ireland. It is
formed as usual by the widening of joints in the Carboniferous
Limestone, and the deposits on the floor consist not only of the
ordinary cave-earth and stalagmite but also of sand and gravel
introduced by water. The cave, in fact, must have been subjected
to numerous inundations, and it can never have been suitable for
habitation by man. As described by Professor H. J. Seymour, all
the pebbles in the introduced gravel are of local origin, whereas
many of those in the boulder-clay of the surrounding country are
granites from a considerable distance. Some of the deposits
containing bones may therefore be of pre-Glacial date. The lowest
layer yields especially remains of a brown bear (Ursus arctos) as
large as the American Grizzly—certainly not the familar cave-bear.
The next layer in some places is crowded with the bones, teeth, and
coprolites of the cave-hyzna, with remains of the reindeer and the
young mammoth which it dragged into the cave for food. The
discovery of a hyzna-den in Ireland is especially interesting; and
the proof that the hyena and reindeer were contemporaneous is
important. As might be expected, all the remains of the reindeer
are very fragmentary; but Dr. R. F. Scharff, who reports on the
mammals, has studied all the known Irish specimens of reindeer,
including a fine skull from a bog near Ashbourne, co. Meath, and
concludes that they represent a peculiar race which he names
Rangifer tarandus hibernicus. Among truly Pleistocene mammals
there are also the Arctic fox, wolf, hare, Scandinavian lemming,
a new form of Arctic lemming, and the Irishdeer. Numerous bones
of birds, determined by Mr. EK. T. Newton, also occur, but do not
include any extinct or noteworthy species. Asi S eos
1 “* The Strength of the Harth’s Crust’’: Jowrn. Geol. (Chicago), vol. xxii,
p. 313, 1914. ‘lhe whole investigation is in eleven sections, scattered through

128 Notices of Memoirs—Fossil Man vn South Africa.

Il.—Fossiz Man in Sourn Arnica.

1. Pretiminary Nore on tae Ancient Homan Sxkui-remarns
FROM THE ‘l'ransvaat. By S. H. Haveuron. With notes
appended on Fragments of Limb-bones, by R. B. THomson, and
Fragments of Stone, by L. Périnevry. Trans. Roy. Soe.
S. Africa, vol. vi, py 1-14, pls. i-x, 1917.

2. Fossizr Man in Soura Arrica. By Roserr Broom. American
Museum Journal, vol. xvu, pp. 141-2, 1917.

ELL-FOSSILIZED portions of a human skeleton were
discovered in 1913-14 in a cultivated field on the farm of
Kolonies Plaats, Boskop, in the Potchefstroom district of the
Transvaal. The greater part of a skull-cap, a temporal bone, the
horizontal portion of the left mandibular ramus, and some fragments
of limb-bones were recovered; but it is uncertain whether the
remains represent a burial, and there are no associated fossils or
implements to indicate their age. A preliminary description of these
interesting specimens is now published and helps to dispel some
of the sensational illusions which were derived from newspaper
reports at the time of the discovery.

The skull is rather thick, its thickness at the parietal boss being
13 to 14mm. _ Its brain-capacity is also remarkably large, probably
not less than 1830c.c. he cephalic index is about 75, so that the
specimen is almost dolichocephalic. The forehead is steep, without
prominent brow-ridges; but the temporal bone is primitive in the
shallowness of the glenoid fossa for the mandibular articulation and
the prominence of the supramastoid ridge. The mandible seems to
have had a prominent bony chin, and the total length of the molar-
series must have been as short as that of the modern European, less
than that of the Australian. The second molar, typically modern
human, is the only tooth preserved; and the alveoli of the other
teeth are too imperfect to determine much of their proportions. On
the whole, Mr. Haughton thinks it ‘‘ possible that the Boskop man

was a mem ber of a race which ultimately developed into the
Bantu type”’

The limb-bones found with the skull are too imperfect for
discussion, especially in their present encrusted state, and the three
plates of photographs devoted to them are not illuminating.
According to Dr. Péringuey, no stone unplemenes have yet been
met with at the same spot.

Dr. Broom expresses the opinion that the Boskop man is
intermediate between Hoanthropus and the early African type of
man. In fact, he considers there is ‘‘ no doubt that the canine was
about as large as in the jaw which he still believes belongs to the
Piltdown skull’. He also thinks the incisors were much larger
than in modern man. Mr. Haughton’s description and figures,
however, lend no support to these views.

J itSho NA

Notices of Memoirs—Ice Age and Antarctic Research. 129

II].—Tuer Bearrne oF THE Facts REVEALED By Anrarctic ResEaRce
UPON THE ProBiEMS oF THE Ice AcE.' By Marspen Manson,
C.E., Ph.D., Mem. Amer. Soc.C.E., San Francisco, California.
From Science, n.s., vol. xlvi, No. 1200, pp. 639-40.

ECENT Antarctic explorations and researches have yielded

significant evidence regarding the problems of the Ice Age, and

of the similarity of the succession of geological climates in polar
with those in other latitudes.’

These researches have been prosecuted to the ultimate limit of
courage, devotion to duty, and endurance—the noble sacrifice of life
—as in the cases of Captain Scott, R.N., and his devoted companions
and members of the expedition of Sir Ernest Shackleton.

The data secured by these expeditions are alone sufficient to
establish the following premises :—

1. That Antarctic ice, although covering areas several times larger
than all other ice-covered areas, is slowly decreasing in extent and
depth.

2. That the same succession of geological climates have prevailed
in Antarctic as in other latitudes.’

So vital are these evidences of the retreat of Antarctic ice that it
may be well to briefly quote or refer to the most prominent instances :
‘¢ All these evidences and many others which space will not allow
me to mention lead up to one great fact—namely, that the glaciation
of the Antarctic regions is receding.* The ice is everywhere
retreating.» The high level moraines decrease in height above the
present surface of the ice, the débris being two thousand feet up
near the coast and only two hundred feet above near the plateau.
(Scott’s lecture on the great ice barrier.*)”’

This observation applies to an ice-covered area of over 116,000
square miles.

Mr. Griffith Taylor notes the recession of Dry Valley Glacier
twenty miles from the sea below Taylor Glacier.’

Mr. Taylor also notes and speaks with confidence of the passage of
the Ice Age from Antarctica.*

In speaking of the evidence of ice retreat over Antarctic areas

1 This term as used by the writer refers to the Great Ice Age of Pleistocene
time. He holds that the occurrences of ice as a geologic agent of magnitude
during eras preceding the Pleistocene were not ‘‘worldwide’’ nor as
“* phenomenal’’, nor were they preceded, accompanied, nor followed by
conditions as significant as corresponding phenomena of the Ice Age. Compte
Rendu du XIéme Congrés Géologique International, Stockholm, 1910,

. 1105.
Ps Scott’s Last Expedition, vol. ii, p. 206.

> This part of the evidence is not considered in this paper except inferentially
as bearing upon the general subject.

4 Scott, The Voyage of the‘‘ Discovery’’, vol. ii, p. 416. See also pp. 423-5,
and sketch-map of ice distribution, p. 448.

> Scott, Nateonal Antarctic Expedition, 1900-1904, vol. i, p. 94.

8 Scott’s Last Expedition, vol. ii, p. 294.

7 Thid., p. 286.

8 Ibid., p. 288. See also photograph following pp. 286, 292.

DECADE VI.—VOL. V.—NO. III. 9

130 Notices of Memoirs—Ice Age and Antarctic Research.

explored by him, Sir Ernest Shackleton said: ‘‘Some time in the
future these lands will be of use to humanity.” ?

This impressive and conclusive evidence is corroborated by the
greater and still more impressive evidences of the comparatively
recent uncovering of temperate land areas,* and the progressive
retreat of the snow-line to higher elevations in temperate and
tropical latitudes and towards the poles at sea-level, being far greater
in Arctic than in Antarctic regions. We are therefore confronted
with the conclusions—

1. That the disappearance of the Ice Age is an active present
process and must be accounted for by activities and energies now at
work, and that the use of assumptions and hypotheses is not
permissible.

2. That the rates and lines of retreat are and have been determined
by exposure to solar energy and the temperatures established
thereby ; and by the difference in the specific heat of the land and
water hemispheres.

3. That the lines of the disappearance of ice are not conformable
with those of its deposition, and mark a distinctly different exposure
and climatic control from that which prevailed prior to the
culmination of the Ice Age.

4. This retreat also marks a rise in mean surface temperature
along these new lines, manifestly due to recently inaugurated
exposure to solar radiation and also the inauguration of the trapping
of heat derived from such exposure; which process is cumulative
and has a maximum not yet reached.

The researches under the direction of Captain Scott and Sir Ernest
Shackleton have therefore very rigidly conditioned any inquiry as to
the causes of glacial accumulation and retreat. These conditions
are CORRECTIVE and DIRECTIVE—corrective, in that they have entirely
removed any doubts as to the alternate glaciation of the poles under
the alternate occurrence of aphelion and perihelion polar winters by
the precession of the equinoxes, as advanced by Croll; directive, in
that they have imposed an appeal to energies now active as causes of
retreat, and divested the problem of resorts to the fascinating but
dangerous uses of suppositions and hypotheses. a

They have, moreover, pointed out with unerring accuracy the
vital conclusion that the same energies which have but recently
converted the glacial lake beds of Canada into the most productive
grain fields of the world will in time convert the tundras of to-day
into the grain fields of to-morrow. * =

1 Address to the Commonwealth Club, San Francisco, Calif., November 7,.
1916.

> Slight fluctuations in the retreat of the small residual glaciers in temperate
latitudes are noted in the reports of the Commission on Glaciers of the
International Geological Congress by Professor Harry Fielding Reid. But
the great measures of the progressiveness of glacial retreat are in the past
disappearance of the Pleistocene ice-fields of temperate latitudes and the
present retreat in the Antarctic and Arctic regions.

3 See also Compte Rendu du XIéme Congrés Géologique International,
Stockholm, 1910, p. 1102.

Notices of Memoirs—Yorkshire Naturalists’ Union. 1381

The bearing of this conclusion upon the ultimate development of
the human race is so far-reaching in its consequences that the great
sacrifice of life attendant upon the prosecution of these researches
stands forever as a memorial in the correction of the erroneous and
widespread conception that the earth is in a period of refrigeration,
desiccation, and decay; and establishes the conclusion that it is in
the springtime of a new climatic control during which the areas
fitted for man’s uses are being extended and that the moss of polar
wastes will be replaced by rye and wheat.

1V.—Joun Micuett anp Martin Simpson.

IR ARCHIBALD GEIKIE read as his Presidential Address to
the Yorkshire Union of Naturalists, 1917,,a memoir on John
Michell (1724-93), one of the pioneer geologists of this country.
The memoir, written in Sir Archibald’s delightful style, appears in
full in the Yorkshire Naturalist for January, 1918.

Mr. Thomas Sheppard, remembered recently for his able memoir
on William Smith, read to the Yorkshire Geological Society a paper
on Martin Simpson (1800-92) (see Gror. Mac., February, 1918,
p. 82).

RHEVIEWwS-

I.—Sanps usEep In MANUFACTURES.

1. A Memorr on British Resources oF SANDS SUITABLE FoR Gtass-
makING, witH Nores on cerrain Crusuep Rocks anp REFRACTORY
Mareriats. By P. G. H. Boswetzt. pp. 92. London: Longmans,
Green & Co. 1916,

2. A Supprementary Mrmorr on British Resources oF SanDs AND
Rocks vUsep IN GULAss-MANUFACTURE, WiIrtH NorEs ON CERTAIN
Rerracrory Materrarts. By P.G.H. Boswrert. pp. 92. London:
Longmans, Green & Co. 1917.

3. Brrrish Guass-sanps; THEIR Locarton anp CHaracreristics. By
P. G. H. Boswert. From the Transactions of the Society of
Glass Technology, vol. i, 1917.

4. Norges on American Hica-crapr Guass-sanps. By P. G. H.
Boswrtt. From the Transactions of the Society of Glass Tech-
nology, vol. i, 1917.

5. Some Gxotoatcat Caaracrers or Mourpine-sanps. By P.G. H.
Boswett. Reprinted from the Foundry Trade Journal, August,
ON c

6. Sanps vusep IN MeratturercaL Practice, with CoMPARATIVE
Nores oN THOSE USED IN GLASs-MANUFACTURE. By P. G. H.
Boswett. Reprinted from the Journal of the Society of Chemical
Industry, 1917.

\HE petrology of the sedimentary rocks is a subject that has been
unduly neglected until recent times. Considerable attention

was devoted to the matter by Professor Bonney, mainly in connexion
with cemented types which could be studied in their slices. ‘he
early investigations of Retgers, Dick, Thoulet, Bréon, and others may

132 Revriews—Prof. Boswell—EHconomic Uses of Sands.

also be mentioned, but the study on modern lines of the unconsolidated
sediments may be said to date from the classical work of Dr. Thomas
on the Trias sands of the West of England. Since then much work
of high scientific value has been carried out by Mr. Crook,
Mr. Bosworth, and other. Asis well known, Professor Boswell has
made an extensive study of the mineral constitution of sediments,
and when the investigation of sands became a matter of urgent
practical importance his knowledge of methods and technique
rendered most valuable service. The six publications above cited
contain the results of work carried out by him at the instance of the
Ministry of Munitions. The first on the list has already been
reviewed in these pages and is only included here for the sake of
completeness.

On the outbreak of war a large part of the imported supplies of
sand and other similar materials failed, and manufacturers were
driven by sheer necessity to inquire into the British resources that
might be available to replace them. Sand is used on a large scale
for many industrial purposes: in metallurgy it is employed for
moulding and as a refractory material ; it is the fundamental necessity
of glass-making, and it is also used for building, for filtration, as an
abrasive, and for many other purposes. The author describes very
fully the characters essential for each particular purpose. For glass-
making the criterion is purity: a sand adapted for high quality glass
should consist as nearly as possible of pure quartz, while what are
commonly known as ‘‘heavy minerals’ should be in the smallest
possible quantity. Iron compounds spoil the colour, while such
infusible substances as zircon and rutile produce flaws. Recent
research has shown that the presence of a small amount of alumina is
not really deleterious, hence felspar up to a certain proportion is not
objectionable. Hvenness of grain is also important, since it leads to
uniform and regular fusion. The requisites for a moulding sand are
that it should consist mainly of fairly large grains with a sufficient
amount of very fine binding material, thus having a large water-
holding capacity. The sands of the Trias best fulfil these require-
ments. Other sands are now often employed with an artificial
binding material.

No British glass sands are quite equal in quality to the very best
imported kinds, such as those of Fontainebleau and Lippe, but we
possess material suitable for even the best kinds of optical glass,
while our reserves of sand available for common glass are practically
inexhaustible.

The properties of a sand depend on several factors, of which the
most important are chemical and mineralogical composition and
texture. The first two are obviously interdependent, and in their
investigation the methods devised for geological purposes are of the
utmost value. The texture, which is equivalent to size of grain, is
determined by mechanical analysis, using the methods devised for the
study of agricultural soils. It is clearly shown that the state of
division is a matter of the greatest practical importance, since it
controls to a very large extent the physical properties on which so
much of the value of the sand for metallurgical purposes depends.

Reviews—A. L.du Toit—Phosphates of Saldanha Bay. 133

Very large quantities of sands, crushed rocks, clays, and other similar
materials are also employed as what may be called for convenience
‘‘refractories’’ in many industrial processes carried on at high tem-
peratures. This subject is dealt with briefly by Professor Boswell.
It is known, however, that an investigation on a large scale of British
resources of refractories has been carried out by the Geological Survey,
and the publication of their results will be awaited with much
interest.

It is apparent that the detailed study of sands, undertaken
originally for purely geological purposes, has proved of great practical
and economic use, thus affording one more instance, if one were
needed, of the ultimate value of pure science for industrial ends, a
fact which has long been recognized and acted on in Germany, but
which the people of this country are only just beginning to realize.

R. H.R.

I].—Rerorr on THE PuospHates or SatpanHa Bay. By A. L.
pu Torr. Memoir 10, Geological Survey of the Union of South
Africa. pp. 34, witha map. Pretoria, 1917. Price 2s. 6d.

(J\HE region described in this report lies on the west coast of Cape

Colony: the country consists of granite, quartz-porphyry,
surface limestones, and blown sand. Along the coast are raised
beaches. In connexion with these a small quantity of good quality
phosphorite has been located, while in addition there are great
masses of phosphate of alumina and iron of much less agricultural
value. It is hoped that a special method of treatment that has been
devised will enable this phosphate to be used as a fertilizer. The
origin of the phosphate is interesting. It is due to the percolation
of solutions from guano into limestones, shell-beds of the raised
beaches, and other detrital deposits. Even boulders and chips of
granite and porphyry are more or less phosphatized. The whole
phenomenon is compared by the author with Sir J. J. H. Teall’s
classical description of Clipperton Atoll, where a trachyte has been

phosphatized by a similar process.
R. H. R.

IlI.—Reporr on tHE Burtpine and ORNAMENTAL Srones oF Canada.
Vol. IV: Provinces of Manitoba, Saskatchewan, and Alberta. By
Wittiam A. Parks. pp. xiv+3338, with 56 plates and 7 drawings
and maps. Ottawa: Government Printing Bureau, 1916.

IYVHIS, the fourth, volume of the excellent series of reports on the

building and ornamental stones of Canada which is issued under
the auspices of the Canadian Department of Mines, deals with the
products of the three provinces of Manitoba, Saskatchewan, and
Alberta, and is from the pen of Dr. W. A. Parks. As he states in
the letter of transmittal to the Director of the Mines Branch, in the
earlier volumes attention was paid only to actual quarries, whereas
in the present one the scope has been enlarged so as to include
possible sources of supply which have not yet been exploited, and
‘in consequence of this change of plan the report has reached

134 | Reviews—Canadian Building Stones.

a length, compared with the earlier volumes, which is somewhat out
of proportion to the relative importance of the building stone
industry in the three Provinces under consideration ’’.

In the opening chapter the author gives a general account of the
building stones of the three provinces, and briefly explains the
nature of the physical tests to which the several samples have been
subjected in order to ascertain their suitability for the purpose and
their capacity to withstand weathering. The determinations made
included the specific gravity, weight per cubic foot, porosity, ratio of
absorption, coefficient of saturation, crushing tests (dry, wet, and
frozen), transverse and shearing strength tests, and corrosion,
drilling, and chiselling tests. In the corrosion test cubes of the
stone under investigation were suspended in water through which
carbonic acid gas and oxygen were passed, and the whole operation
took four weeks, the water being changed twice weekly. Mr. MacLean,
who was in charge of this part of the investigation, discovered that
the rate of solution of limestone was materially affected by the
pressure maintained in the containing bottle, and he devised special
apparatus for keeping the pressure constant. The provinces in
question do not as yet yield much diversity of building stone, the
present supply being confined to the mottled limestones of Tyndall in
Manitoba and the Paskapoo Sandstones of Alberta, but there are
possibilities of other occurrences of these stones being worked as
soon as the demand justifies it. ‘The eastern ranges of the Rocky
Mountains, which come within the scope of the book, cannot be
drawn upon for building stone to any great extent, because the
limestone of which they chiefly consist is so hard and shattered as to
be unsuitable for the purpose.

A concise discussion of the geology of the region is the subject of
the following chapter. As is well known, its most conspicuous
physical character is found in the great prairie plains which stretch
from the rocky district of the Manitoba lakes and Lake Winnipeg on
the east to the foothills of the Rocky Mountains on the west, and
building stone can only be looked for on the margin of the plains
owing to the thickness of the soil over the whole of them. In the
remaining eight chapters the various rocks furnishing building stones
are considered in detail, commencing with the limestones and sand-
stones, and passing on to the miscellaneous rocks and ornamental
stones; while the physical characters of the stones and statistical
data are tabulated in appendices.

The Tyndall Limestone has been used for such important buildings
as the Parliament buildings at Regina and the Post Office at Moose
Jaw in Saskatchewan, and the Post Office at Lethbridge in Alberta ;
while the Paskapoo Sandstone has been selected for the Court House
at Lethbridge, the Royal Bank at Medicine Hat, the Court House and
Parliament buildings at Edmonton, Knox Church, the Land Titles
building, City Hall, and the Carnegie Public Library at Calgary, in
the province of Alberta. Photographs of all these buildings are
included among the numerous illustrations. There are also six
plates in colour showing sections of limestone, granite, and sand-
stone.

Reviews—Geology of Transkei, South Afroca. 1385

IV.—Tue Gerotogy or Parr or tHE Transxer. EXpLanaTION oF
Suerr 27, (Carn) Mactear—Umrata. By A. L. pu Toir; with
an introduction by A. W. RogezErs, Geological Survey. pp. 32.
Pretoria, 1917. Price 2s. 6d.

fF\HIS memoir is to accompany the map on the scale of 3°75 miles

to an inch, prepared by Dr.du Toit. The map contains a very
large amount of detail, considering the character of the country,
which includes part of the great Drakensberg escarpment and rises
to a height of some 9,000 feet. The area surveyed is entirely com-
posed of the rocks of the Karroo system and their accompanying lavas,
ashes, and intrusions. The whole of the Karroo system is repre-
sented and reaches the great thickness of 14,000 feet, exclusive of
the Stormberg lavas, which are about 3,000 feet more. The strata
are normal in character and contain plants and reptiles, hence
horizons can now be fixed with fair accuracy, since it has been found
possible to establish reptile zones in this formation. Some coal-
seams of workable thickness are found in the Molteno beds. A con-
siderable number of volcanic necks have been located, and the Karroo
dolerites have been intruded on an enormous scale, chiefly in the

Keea and Beaufort series.

Perhaps the most interesting part of the memoir is the description
of the copper-nickel bearing area of Insizwa and Tabankulu. The
ores occur at the lower contact of great cakes of gabbro-norite, a
special phase of the Karroo dolerites, intruded into the lower division
of the Beaufort beds. These masses, which are about 3,000 feet
thick, have undergone magmatic differentiation by gravity, the
lower part being a picrite, followed by olivine-norite and norite; at
the top there is even a little quartz as micropegmatite. The Insizwa
mass is some ten miles in diameter. ‘lhe ores occur at the base of
the intrusion and also to a certain extent in the country rock close to
the contact. ‘he principal minerals are pyrrhotite, chalcopyrite,
and pentlandite, with smaller amounts of niccolite and bornite and
some oxidized copper and nickel minerals. Platinum has been found
by assay up to 1 oz. per ton, but it is not yet known in what form it
occurs. There is also a little gold. The ores were undoubtedly
formed by differentiation from the norite magma, and the whole
occurrence is very similar to the famous nickel deposits of Sudbury,
in Ontario. From the geological relations it appears highly probable
that the amount of ore will increase in depth when followed below the
intrusion. The deposits are now being actively developed, and it
seems probable that they will eventually prove to be of great com-
mercial value.

ebay.

V.—Low-tTemPrrature Formation oF ALKALINE Freispar 1N LiMe-
stonn. By R.A. Dany. Proceedings of the National Academy

of Sciences, vol. ili, pp. 659-65, 1917.
UTHIGENIC Peale of felenee including orthoclase, albite, and
perhaps microcline, have been described by various authors in
the Jurassic limestones of the Alps and in the Chalk of the Paris
Basin. The crystals are well-shaped, but very minute, and are

186 Reports & Proceedings—Geological Society of London.

supposed to have been formed on the sea-floor during the deposition
of the sediment: in the case of the Paris Basin, at any rate, thermal
metamorphism is excluded. With these observations Mr. Daly com-
pares a remarkable dolomite in Alberta, probably of Pre-Cambrian
age. It consists chiefly of grains of carbonate of rhombohedral form,
but certain layers are heavily charged with clumps and interlocking
grains of glass-clear orthoclase, from 0°01 to 0:05 mm. in diameter,
and without good crystal form. The total amount of felspar is
estimated at 37 per cent of the rock. It is suggested that these
crystals were also developed during the deposition of the sediment at
the ordinary temperature.

R. H. R.

REHEPORTS AND PROCHEDINGS.

I.—Geonoeicat Socrery or Lonpon.
1. January 9, 1918.—Dr. Alfred Harker, F.R.S., President, in the
watt Chair.

The following communication was read :—

“The Highest Silurian Rocks of the Clun Forest District
(Shropshire). ” By Laurence Dudley Stamp, B.Sc., A.K.C.L.
(Communicated by Dr. A. H. Cox, F.G.S.)

Clun Forest is a large district—extending on both sides of the
Welsh Border—in which Upper Silurian rocks crop out over a wide
area, interrupted by outliers of Old Red Sandstone. The district is
separated from the typical Silurian area of Ludlow, which lies some
15 miles away to the east, by the great line of disturbance that
passes through Church Stretton and Old Radnor.

The classification adopted for the highest Silurian strata is as
follows :—

Thickness
in feet.
OLD RED SANDSTONE 3 : : Purplish-red sandstones.
Temeside Shales. . 350 Olive-green shales with bands

of micaceous green grit; a
fragment-bed, with Huryp-

TEMESIDE terid and plant remains,
GROUP. forms the upper limit.
Downton Castle Sandstone 110 Yellowsandstones and tilestones,
Series. with shales and Platyschisma
Limestones.
Upper . 50 Green laminated flags and blue
flagstones.
Cae ious beds Lower . 300 een bedded calcareous
OW
Ceonn | flagstones. ‘
Rhynchonella Beds . . 300 Grey calcareous flags with
massive blue flagstones.
AYMESTRY f Dayia Shales . : ?300 Striped laminated shales and
GRouP. \ mudstones.
Lower Ludlow Shales é Dark-grey shales and indurated
el mudstones.
Total . : 1410

The distribution and characters of the beds are described. The
succession compares very closely with that in the Ludlow district

Reports & Proceedings—Geological Society of London. 137

itself. The main differences are: (1) that the Aymestry Limestone
is represented by mudstones west of the great fault-line, and (2) that
all other divisions show greatly increased thicknesses.

There is no evidence of any stratigraphical break. On the contrary,
the sequence is complete from the Lower Ludlow rocks up into the
Old Red Sandstone, and the changes in lithology are usually quite
gradual. The oncoming of the Old Red Sandstone conditions is
discussed, with regard to their effect on the lithological and
paleontological characters of the strata.

The extent of Old Red Sandstone, as indicated on present maps,
must be greatly restricted, since most of the supposed Old Red
Sandstone has been found to belong to the Temeside Group, which
in this district attains a great development. The Silurian age of the
beds in question is shown by the occurrence in them of Lingula
minima, and of characteristic Lamellibranchs, etc., also by comparison
with similar strata in the Ludlow area.

A comparison with other districts in which Upper Silurian rocks
are developed shows that deposition attained its maximum along the
Welsh Border, the thickness of the formations decreasing rapidly
southwards and eastwards.

On the east of the district, in the neighbourhood of the great
fault-line, the strata are considerably folded along axes ranging
north-north-eastwards, parallel to the main fault, with minor faults
following the same direction. Away from the major faults the
folding is gentler in character, and a series of folds ranging nearly
due east and west make their appearance. Farther west the north-
north-eastward folding and fracturing reappear.

2. January 23, 1918.—Dr. Alfred Harker, F.R.S., President, in the
Chair.

The following communication was read :—

‘On a Flaked Flint from the Red Crag.” By Professor William
Johnson Sollas, M.A., Sc.D., LL.D., F.R.S., V.P.G.S.

The remarkable specimen forming the subject of the paper was
obtained by Mr. Reid Moir from the base of the Red Crag exposed in
the brick-pit worked by Messrs. Bolton & Company near Ipswich.

It is a fragment of a nodule of chalk-flint, irregularly rhombic in
outline, with a nearly flat base and a rounded upper surface ‘which
retains the whitish weathered crust of the original nodule.

The base was formed by a natural fracture which exposes the fresh
flint bordered by its weathered crust.

Both upper and under surfaces of the specimen are scored with
scratches which are mainly straight, but in some cases curvilinear.

Two adjacent sides have been flaked by a force acting from below
upwards, in a manner that recalls Aurignacian or Neolithic workman-
ship. The two edges in which the flaked faces meet the base are
marked by irregular minute and secondary chipping, such as might
be produced by use. On the hypothesis that the flint has been flaked
by design, these edges will correspond to the ‘‘ surface d@’utilisation ”’
of M. Rutot, and we should expect to find on the opposite edges of
the flint the ‘‘ surface d’accommodation ”’, as in fact we do.

g
2

138 Reports & Proceedings—Ceological Society of London.

A singular feature, which seems difficult to reconcile with its use
as an implement, is the restriction of the flaking on one edge to the
_ weathered crust.

The origin of the flaking is discussed, and the author, while
admitting that the fashioning of the flint is not inconsistent with
intelligent design, concludes that the evidence is not sufficient to
establish this beyond dispute. Itiseminentlya case of ‘‘not proven”’

The Secretary read a letter from Mr. J. Reid Moir, in which he
stated that the flint in question was found by him in the detritus-
bed below the decalcified Crag in the brickfield of Messrs. Bolton
and Co., Henley Road, Ipswich, and that the author at first accepted
the specimen as being of undeniable human origin. Mr. Reid Moir
further expressed the opinion that the flaking to be seen upon the
specimen was ‘‘human’”’ in its characteristics, and referred to his
printed papers in support of that opinion.

3. February 6, 1918.—Dr. Alfred Harker, F.R.S., President, in the
Chair.

The following communication was read :—

“Some Considerations arising from the Frequency of Earthquakes.”
By Richard Dixon Oldhan, F. i See Gas:

The publication ‘of an abstract of twenty years record of earthquakes
in Italy gives an opportunity for studying the effect of the
gravitational attraction of the sun; the period is so nearly coincident
with the lunar cycles of 19 and 18°6 years that the effect of the
moon may be regarded as eliminated, the record is of exceptional
continuity and completeness, and the number of observations is large .
enough to allow of the extraction of groups sufficiently numerous to
give good averages.

The distribution of the stresses is dealt with in textbooks; there
is a maximum upward stress, in diminution of the earth’s attraction
at its surface, at the two points where the sun is in the zenith or
nadir, and a maximum downward stress along the great circle where
it is on the horizon; but as, for the purpose of this investigation,
a decrease of downward pressure is equivalent to an increase of
upward, I shall take the line along which the downward stress is
greatest as the zero-line, and express the amount of stress at any
other time or place as a fraction of the difference between the net
force of gravity along this line and at the point where the sun is in
the zenith. The fraction, at any given time and place, depends
solely on the zenith distance of the sun, which is continually varying
with the revolution of the earth. At the equinox, when the sun is
on the equator, the curve of variation between 6 a.m. and 6 p.m. is
the same as in the other half of the day; at any other part of the
year it is not symmetrical in the two halves of the day, but is the
same during the day in the summer half of the year as during
the night in the corresponding part of the winter half, when the
declination of the sun is equal in amount, though opposite in
direction.

} Boll. Soc. Sismol. Italiana, vol. xx, p. 30, 1916.

Reports & Proceedings—Geological Society of London. 139

This gave the first suggestion for grouping the records. The year
was divided into two halves by the equinoxes, and the day into two
halves, at six hours before or after noon, called day and night for
convenience, irrespective of the time of sunrise or sunset. The
result is given in the tabular statement below, the frequency being
expressed as a ratio to the mean, of each group, taken as 100 :—

DISTRIBUTION OF SHOCKS BY DAY AND NIGHT.

Italy, 1891-1910. Day. Night.
June—July : : * : a) SOW ALO!
Summer half . 5 : : Aid rctown muse] Lt
Whole year . : : : . 84 : 116
Winter half . : : : Sun ted eases ug LLG)
December—January . ‘ : Aan Ae) tbe)

Japan, 1885-1892.

Summer half . : : j 5 Me 8 Os
Whole year . Ba POs 4 ea O FL cnr sua Oss
Winter half . : : : MO Sian taiellOzs

Assam Aftershocks.

Summer half . : ; : a NB Be By
Whole year . : ‘ 6 5 NOY Sy OB
Winter half . : 3 oe OIE 384 BH)

From this statement it will be seen that the mean ratio of day to
night shocks over the whole period is represented by the figures
84:116; for the summer half of the year they become 88: 112, and
for the winter half 81: 119, showing that during the day the shocks
are somewhat less frequent in the winter, with an opposite variation
during the night. Taken by itself this difference might be merely
fortuitous, and further confirmation is required: this can be got
in two ways. In the first place by comparison with other records,
two of which, Milne’s catalogue of Japanese earthquakes from 1885
to 1892’ and the aftershocks of the Indian earthquake of 1897,
stood ready for use. ‘They show a variation identical in character
with that of the Italian record. A second test depends on the
argument that, if the variation is in any way seasonal, the divergence
should be increased at the height of each season; the figures for the
months of January—February and of June-July were taken out, as
representing midwinter and midsummer respectively, and found to
show a divergence in each case greater than, and in the same
direction as, the respective half-years.

Taken by itself the variation, as between any pair of ratios, is as
likely to be in one direction as in the other, but the odds against
a complete concordance throughout the whole series is 31 to 1;
there is, therefore, a strong presumption that the variations are not
fortuitous, but due to some common cause which tends to increase
the frequency during the day and decrease it during the night in
summer, with the opposite in winter.

The variation in the frequency of earthquakes may, or may not,
be connected with the variation in the gravitational stresses due to
the sun; but there is another line of investigation by which
a connexion may be better traced, dependent on the fact that the
prevailing effect of the vertical stress is in the direction of lightening

1 Seismol. Journ. Japan, vol. iv, 1895.
2 Mem. Geol. Surv. India, vol. xxxv, pt. ii, 1903.

140 Reports & Proceedings—Geological Society of Lonaon.

the load, and the prevailing direction of the horizontal stress
between east and south, during the six hours before the meridian
passages at noon and midnight, and of an increase in the downward
pressure and a horizontal stress between south and west during the
next six hours. The record was accordingly grouped by the
successive two-hour periods from XII to XII o’clock, and the mean
amount of variation in the stresses was calculated for the same
periods. The result is set forth in the appended tabular statement :—

DISTRIBUTION OF STRESSES AND SHOCKS 1N Two-HouR PERIODS,
BEFORE AND AFTER MIDDAY AND MIDNIGHT.

Hours . : . XII II Til VI VIII xX XII |

STRESSES.
Mean range of stress in each
two-hours, in Italy.

Total stress . j : . | —710| —-27| —-23| +-23 | +-27 | +-10
Horizontal component . . | +:07 | —-11}) —-20} +-20] +-11 | —-07
Vertical component . . | —:14] —-27| —-13 | +-13 | +-27] 4-14
SHOCKS.

Ratio of actual to mean fre-
quency of each two-hour
period.

ITauy, 1891-1910 : . | 1-06) 1:17] 1-01) «-90 88 99

JAPAN, Aftershocks of Mino-
Owari, October 28, 1891 .| 1-01 95 °96 -97 | 1:08) 1-03
JAPAN, 1885-90 . : . | 1:00} 1-11 “89 -98 | 1-C3 -99

From these figures it is seen that, while there is no apparent
relation between the frequency and the total, or the horizontal,
stress, there is a close one with the variation of the vertical stress ;
the greatest number of earthquakes being in the period in which
there is the greatest increase of downward pressure; as the rate of
increase diminishes the number of shocks is less, suffering a further
diminution as the pressure begins to decrease, and reaching its
minimum in the period where the decrease in pressure is greatest,
increasing again in the same way to the maximum.

An attempt to apply the same method to the Japan record gave
a result which was, at first sight, contradictory and also inconsistent
in itself, for it gave an absolute maximum at the time when the
Italhan gave a minimum, with another maximum, almost as great,
in coincidence with the Italian; but, in any comparison, it is
necessary to allow for the contrast in the character of the two
records. The Italian does not contain more than two, or at most
three, great earthquakes of the type that gives rise to long-distance
records (bathyseisms), and the aftershocks account for no more than
a quarter of the whole record; the Japanese record, on the other
hand, is dominated by bathyseisms and aftershocks. Not only does
the region give origin to an unusually large number of teleseisms, or

Reports & Proceedings—Geological Society of London. 141

bathyseisms, but aftershocks form fully three-quarters of the record,
and nearly a half consists of aftershocks of the Muino-Owari
earthquake of October 28, 1891. Taking these separately, we get
a curve of frequency similar to the Italian, except that the maximum
and minimum are reversed, the greatest number of shocks corresponding
to the period when the load is being lightened most rapidly,
indicating that these shocks are due to a general movement of
elevation rather than depression, a conclusion in accord with field
observations of other great earthquakes. In addition, the shocks
which occurred during the period 1885-90 were taken out, as
representing a more normal activity, though still one in which
aftershocks form fully half of the record, and the curve was found,
as might have been expected from the character of the record, to
combine the features of the Mino-Owari aftershocks with those of
the Italian curve of frequency, of earthquakes prevailingly of the
so-called ‘‘ tectonic ’’ type.

These results are of twofold geological interest. In the first
place they confirm the conclusion drawn from a study of the
Californian earthquake of 1906,’ that the great earthquakes differ
from the ordinary, not merely in degree but in kind. ‘They indicate
that in the latter the main stress is compressive, probably due to
settlement, and in the former to elevation or tension, a conclusion
which is in accord with the fact that, in those cases in which it has
been possible to compare accurate measurements made before and
after the earthquake, the comparison has indicated an expansion,
elevation, or both, of the area affected by the disturbance.

The second point of interest is that the figures give a means of
estimating the rate of growth of the strain which produces earth-
quakes. If we accept the hypothesis that earthquakes, in the
limited sense of their orchesis, are due to the relief by fracture of
a growing strain when this has reached the breaking point, it can be
easily shown that a variable strain, acting in alternate periods in
increase or decrease of the general growth of strain, while leaving
the average rate unaltered, will give rise to a corresponding variation
in the frequency of shocks in each period; and, besides that, there is
a simple relation between the magnitudes of the two stresses, to
which the strains are due, and the variations from the mean
frequency of earthquakes. A calculation on these lines shows that
the growth of strain, for Italy, is such that, accepting the published
estimates that an area of the earth’s crust of the magnitude of Italy
would crush under its own weight if left unsupported to the extent of
zoo of the force of gravity, the breaking strain would be reached
in about 33 years, starting from a condition of no strain. The
aftershocks of the Mino-Owari earthquake give a little less than half
this figure, which is again reduced to from five to six months if
account is taken of the difference between the resistance of rock to
tension and to compression. ‘hese figures are given for what they
are worth; at the least, they are of interest as being the first
authentic estimate which it has been possible to make of the time
required to prepare for, and, thence, of the rate of growth of the
particular tectonic process involved in the production of earthquakes.

1 Q.J.G.S., vol. lxv, p. 14, 1909.

142 Reports & Proceedings—Geological Society of London,

4. February 20, 1918.—George William Lamplugh, F.R.S. eer
in the Chair.

The following communication was read :—

‘“The Geological Aspects of the Coral Reef Problem.” By
Professor William Morris Davis, For. Corr.G.S.

The communication is a critical review of the various theories
that have been put forward up to the present time to explain the
origin of coral reefs. A voyage in the Pacific, made in the year
1914, enabled the author to collect new evidence bearing upon the
question, and to make observations that have influenced him in his
support of Darwin’s theory.

After laying stress upon the embayment of shore-lines as a a proof
of subsidence, the author expresses the opinion that all theories that
postulate a fixed relation between reef formation and ocean level are
disproved, and are probably inapplicable to the case of atolls. It
appears certain that reef upgrowth is intimately associated with
submergence wherever the matter can be tested. The solution of
the coral reef problem turns at present upon some means of dis-
criminating between a submergence caused by subsidence and a sub-
mergence caused either by a general rise of the ocean level due to
the uplift of the ocean floor beyond the coral reef region or to the
melting of the Pleistocene ice-sheets. Although no means of such
discrimination are known, the author presents reasons that lead him
to regard changes in ocean level as of secondary importance, and that
have caused him to attribute the submergence demanded by self-
encircled islands to local subsidence, in accordance with the views of
Darwin and Dana. He regards the theory that presupposes the
raising of the ocean level by uplift as extravagant in its demands,
and he finds the theory of ‘‘Glacial Control’? inadequate when
applhed to barrier reefs and encircled islands.

Stress is laid on the highly significant unconformable relationship
that exists between reef and lagoon limestones and their foundations
a feature that presents the strongest testimony for subsidence.
In such a case the foundations must have suffered erosion for a con-
siderable period before they were submerged, in preparation for the
unconformable deposition of reef limestones upon them. From
a consideration of such unconformable relations it is concluded that
fringing reefs do not mark stationary or rising islands as generally
as Darwin supposed.

With regard to elevated reefs, the author demonstrates the
impossibility of explaining their features by regarding them as
having been stationary while the ocean surface was lowered, and
holds that they must be due to local and diverse uplift affecting the
islands themselves, following on epochs of subsidence which were
the epochs of reef formation. The theory that such reefs were
formed during pauses in the elevation and emergence is considered
to be seriously defective, and is contrary to Darwin’s views.

The author discusses the studies of Semper on the reefs of the
Pelew Islands, the origin of atolls as propounded by Rein, the views
of Murray on barrier reefs and atolls, and of Wharton on the
truncation of atoll foundations; but forms the opinion that the

Reports & Proceedings—Hdinburgh Geological Society. 143

geological evidence for subsidence has been overlooked by these
investigators, who paid no attention to the evidence afforded by
unconformable contacts or embayed shore-lines.

The author feels that scientific opinion in regard to the origin of
coral reefs has been guided rather by subjective preference than by
objective logic. He considers that Darwin’s theory of intermittent
subsidence is the most competent to explain the facts, and while he
holds that other theories than Darwin’s deserve cordial consideration,
he feels that the burden of proof should be laid upon those who
assume that reef foundations have not subsided.

II.—EpinsureH Grotogican Soctery.
January 16, 1918.—Professor Jehu, President, in the Chair.

‘The Supplies in Scotland of Felspars suitable for Industrial
Purposes.” By Dr. Campbell.

Recent investigations of Scottish sources of alkali felspars had
been necessitated by (1) the difficulty of obtaining shipment of the
Scandinavian ‘‘spar’’, which is used extensively in the enamel,
glass, and pottery industries, and (2) the possibility of utilizing
potash felspars as a source of soluble potash salts, hitherto imported
from Germany.

Dr. Campbell gave an account of the results so far obtained of an
inquiry carried out by Mr. Dinham and himself on behalf of the
Geological Survey of Scotland. Pegmatites, the chief source of
alkali felspars, were described from Beinn Ceannabeinne, the district
between Lochs Laxford and Inchard, Rhiconich, and Overscaig in
Sutherlandshire, from the Strontian district of Argyllshire, from
Portsoy, Banffshire, and from Monymusk, Aberdeenshire. It was
shown that, from their high content of silica and iron oxides, many
of the Scottish pegmatites would be classed as spar of Grade 38.
There were, however, abundant supplies of spar of Grade 2, and at
a few localities, particularly at Rhiconich, Strontian, and Mony-
musk, spar of Grade 1 (equal to the best Scandinavian spar) could
be made available by hand-picking. Analyses of the average material
of the best pegmatites gave potash content ranging from 7°42 to
9°35 per cent. The red potash spar at Rhiconich was found to be
associated with a buff-coloured spar containing 7:13 per cent of soda,
which might be separated by hand-picking and utilized in the glass
industry. Estimates were given of the quantity of spar available at
each locality. The most extensive deposits are those at Beinn
Ceannabeinne, where at least 12,000,000 tons could be obtained by
open-cast working.

Certain highly felspathic granites and felsites were regarded also
as likely to be of economic value. Of the granites examined, the
well-known Corrennie granite of Aberdeenshire was most promising.
An average sample of the rock yielded 8-02 per cent of potash, and
the only ferro-magnesian mineral present, biotite, occurs very
sparingly. The spoil heaps in the quarries would furnish an
immediate supply of many thousands of tons, and for practical
purposes the available supplies might be regarded as ‘‘unlimited”’.

144 Reports & Proceedings—Geologists’ Association.

The best of the felsites so far investigated was a sill on the
Kincardineshire coast near Cove Bay Railway Station. The rock
consists essentially of felspar, quartz, and muscovite, and is entirely
free from ferro-magnesian minerals. In chemical composition it
resembles closely a spar of Grade 3 from Kingle’s Quarry, Bedford,
N.Y., which is much used in the enamel and glass industries in
America. It contains 4°67 per cent of potash and 3°53 per cent
of soda.

Attention was directed to various methods by which potash might
be extracted from felspar—in particular to the processes devised by
Rodin and Ashcroft—and to the possibility of utilizing felspar as raw
material in the Portland cement industry, the potash being recovered
as a by-product.

Promising results had been obtained in recent trials made to test
the suitability of Scottish spars for the enamel and pottery industries.
There was thus a possibility of reviving what was an old Scottish
industry since the Monymusk spar was quarried, ground locally, and
shipped to the English potteries in the latter half of the eighteenth
and the beginning of the nineteenth century.

ITI.—Grotoetsts’ AssociaTIon.

The annual general meeting of the Association was held at
University College, Gower Street, W.C.1, on February 2, 1918,
when the annual report of the Council and the accounts for the year
ending December 81, 1917, were presented, and the officers and
Council for the year 1918 elected. The President (George Barrow,
F.G.S., M.I.M.M.) delivered his address entitled ‘“‘Some Future
Work for the Geologists’ Association’’. The President showed that
while the main features of the formations from the Lower Greensand
- to the Upper Bagshot Beds are fairly well known within the London
area there is need for far more accurate knowledge of the occurrence
and pebbly constituents of the Drifts, especially those north of the
River Thames. Even in the Geological Survey maps the colouring
and tiomenclature are much confused. The Drifts may be divided
into two groups—(1) Eastern, (2) Western. Much work remains to
be done in tabulating the distribution and origins of the far-travelled
materials almost always present in the former group. The Western
Drifts, largely of local origin, contain far-travelled materials only in
their lower and smaller portions. An account was given of these
two groups indicating their extension and lines of junction, the
evidence they afford of post-Glacial denudation, and of the pre-
Glacial form of the district. In considering the significance of the
small white quartz pebbles abundantly present in the Western local
drifts, emphasis was laid on their common occurrence at heights
slightly above 400 O.D. and their derivation from the Lower
Greensand, through one or more gaps in the Chalk escarpment,
during a period at least late Pliocene in age, when an estuary
probably occupied the line of the present lower Thames valley.
Brief reference was made to the River Terraces and the associated
Brick-earths, and to localities that require special examination. The
address was illustrated by lantern slides.

BRITISH PETROGRAPHY :
With Special Reference to the Igneous Rocks.

OSB Ys

J. J. HARRIS TEALL, M.A., F.GS.

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i Page - REVIEWS (continued). Page
George Jennings Hinde, Ph.D., | Geology of N.E. Rajputana. By
V.R.S., F.G.S., V.P.Pal.Soc., A> MS Heron’ aes eee ees 175
died March 18, 1918°............ ». 145 | Tvon-ores of Canada. By E.
: S i tp carne Lindeman and L. L. Bolton...... 176
= fs a ae -Great Australian Artesian Basin.
Origin of Land-forms in Caernarvon- By A. hs du Toit ee 177
shire, North Wales. By HENRY Mining Operations in S. Australia. 178
Dewey, F.G.S. (Plate VII and _ | Test of the Subsidence Theory of
two Text-figures.) ...........:...... 145 Coral Reefs. By R. A. Daly ... 178
Origin of Clays and Boulder-clays, New Fossil Corals, Pacific Coast.
Federated Malay States. By By Jorgen O. Nomland ............ 179
Lieutenant J. B. SCRIVENOR,
4 pee eae Map baie eee 157 IV. REPORTS AND PROCEEDINGS.
GSS ei petra cage pear eu Geological Society of London—
a5 imipedes- ey sho a SBS Annual General Meeting, Feb.15 179
‘F.G.S. (With a Text-figure.)... 168 Mian chy Gre tant citk wind acasee ae apes 187
II. Norices oF MEmoIrRs. Edinburgh Geological Society ...... 188
Prehistoric Drawings in Spanish We Onin

Caves. By Eduardo Hernandez-

Pacheco. (With a Text-figure.) 173 | Captain Lewis Moysey, R.A.M.C.,

BEAL NT Bee le Gage esate me oO
Ill. Reviews.

Geological Survey of the South VI. CORRESPONDENCE.
Wales Coalfield. By Dr. A. Drak besshenlockyHaGe Savc..n suse 192
Strahan, F.R.S., and others ... 174 |) E. M. Anderson, M.A., F.G.S. ... 192

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GEORGE JENNINGS HINDE,
Pee eR Se Be Ge. Se. Vike yP Ate SOC.

BorN MARCH 24, 1839. DIED MARcH 18, 1918.

Wirn deep regret we record the loss of our old and valued
friend George J. Hinde, who for thirty-two years (1886-1918)
was an Assistant Editor of the Grotogican Magazine, to which
he has contributed over thirty articles. Dr. Hinde served on
the Council of the Geological Society for nineteen years, and
was a Vice-President in 1893. He was elected a Fellow of the
Royal Society in 1896, held the office of Treasurer to the
Palzeontographical Society for ten years, and became a Vice-
President in 1916. He was awarded the Lyell Medal by the
Council of the Geological Society in 1897.

He passed peacefully away at “ Ivythorn’’, Avondale Road,
Croydon, March 18, 1918. Dr. Hinde’s portrait, his life and
scientific work, together with a list of his memoirs, will appear
in May.—H. W.

ORIGINAL ARTICLES.
—__@——_—_

I.—On tHE OriIGIN oF soME LAND-FORMS IN CAERNARVONSHIRE,
Norta WaAtEs.

By HENRY DEWEY, F.G.S., of the Geological Survey of England and Wales.
(PLATE VII.)

fJ\HE present paper deals with some 30 square miles of land

situated in Caernarvonshire and embracing the drainage area
of the River Ogwen and parts of adjacent river-basins.! It is
doubtful if any part of Great Britain presents in such a small area
so many interesting topographical features and such beautiful and
diversified scenery as this part of North Wales. It is in part
a thoroughly mountainous region accompanied by characteristics that
belong to mountains, and it is a glaciated. mountain region with
typical glacial topography. But adjoining the mountains is an area
of entirely different characteristics, and the change from the one to
the other is sudden and complete. An upland plain abruptly
terminates against a range of mountains without the interposition of

1 See One-inch New Series Ordnance Map, Sheet 106.
DECADE VI.—VOL. V.—NO. IV. 10

146 Henry Dewey—Land-forms in Caernarvonshire.

foot-hills, the crags and pinnacles rising precipitously from the level
_land; or, in other words, the plain cuts as it were a shelf in the
mountainous masses.

Two years ago I communicated to the Geological Society of
London a paper on the ‘‘ Origin of River Gorges in Cornwall and
Devon”’,? and therein described an upland plateau that attains
a maximum altitude of 430 feet above sea-level. In discussing that
paper Mr. E. Greenly and Professor Fearnsides called attention to
the existence in North Wales of similar coastal plateaux, but at
different heights above sea-level from the one I had described. At
the time those comments were made I was under an impression,
gained during a short visit to North Wales in the spring of 1915,
that a precisely similar feature terminating at the same height above
sea-level occurred in both Cornwall and Caernarvonshire. But I was
not sufficiently versed in the land-forms of the latter county to feel
justified in asserting their practical identity. I therefore resolved
to revisit the district to inquire more particularly into these land-
forms, and in consequence spent some weeks during the summers of
1916 and 1917 in making a close investigation of the points to be
solved. Asa natural consequence other problems arose, and one in
particular that cannot be settled in Cornwall or Devon, namely, the
effects of glacial conditions upon this upland plain and the amount of
denudation which has taken place since those conditions terminated.
Restricted railway facilities more or less confined work to the district
around Bethesda, and in consequence I chose for detailed investiga-
tion the valley of the Ogwen and the country lying between
Bethesda and Llanberis, and extending westward to Caernarvon and
Bangor.

Previous LITERATURE.

This district is classic ground. Darwin? recognized the glacial
features of parts of it and described in detail the valley of Llyn
Idwal. Many years afterwards Sir Andrew Ramsay ® (in spite of
great difficulties, especially with regard to inadequate topographical
maps) fully and accurately described the mountainous tract. His
work will be referred to frequently, but it may here be said that its
accuracy is such that it needs but little revision, except where
additions and refinements made possible by more precise methods
and the general advance in geological science have necessitated
modifications of nomenclature. His inferences, however, are open
to question, and have already drawn into controversy many
observers, including Watts, Marr and Adie,® Dakyns,® Jehu,’ and
W. M. Davis.®

Quart. Journ. Geol. Soc., vol. xxii, for 1916, pp. 63-76, published 1917.
Phil. Mag., ser. II, vol. xxi.

1
2

3 The Old Glaciers of Switzerland and North Wales, London, 1860.

4 **Notes on some Tarns near Snowdon ’’: GEOL. MAG., 1895, p. 565.

° ‘The Lakes of Snowdon’’: GEOL. MAG., 1898, p. 51.

6 ** Some Snowdon Tarns’’: GEOL. MaG., 1900, p. 58.

“ “The Lakes of Snowdonia and Eastern Carnaryonshire’’: Trans. Roy.
Soc. Edinburgh, vol. xl, pt. ii, pp. 419-67, 1902.

8 “* Glacial Erosion in North Wales’’?: Quart. Journ. Geol. Soc., vol. Ixy,

pp. 281-350, 1909.

Henry Dewey—Land-forms vm Caernarvonshire. 147

North Wales was perhaps the first district where the former
presence of glaciers was inferred from the characters of its land-
forms. Darwin and Ramsay both described examples of such forms
near Nant Ffrancon as were then acknowledged to be due to glacial
action, namely the moraines, perched blocks, roches moutonnées, lakes,
and the general U-shaped sections of the valleys. Since then other
land-forms have been recognized as equally significant of glacial
agencies, such as arétes, cirques, gendarmes, valley steps, and
hanging valleys. Professor Garwood’ has described typical instances
in the Ticino Valley. Now all these features are preserved in North
Wales, but perhaps nowhere in so characteristic a manner as in the
Nant Ffrancon district. Further, their relationship to earlier land-
forms is equally well revealed in this neighbourhood, and for these
reasons the district is one of particular interest to all students of
geomorphology.

In the following account each feature is described as it is met with
in following the valley from the water-divide downwards to its
confluence with the sea.

Tur Ogwen VALLEY.

The Afon Ogwen rises on the southern slopes of Carnedd Dafydd
as a turbulent mountain torrent, the Afon Dena, and dashes down-
hill among rocks and boulders in a series of rapids and cascades,
pursuing a course roughly parallel with a neighbouring stream that
afterwards flows in a diametrically opposite direction. Near Pont
T'y-coch the two streams reach flat land partly covered with glacial
drift and peat, but beneath these superficial deposits lie solid rock
scored deeply with strie and worn into roches moutonnées. This
low ground, although apparently flat, is the water-divide between the
Rivers Ogwen and Llugwy, and from whatever point it is viewed
appears to be a valley occupied by a sluggish river, which might. be
flowing in either direction.

Tur Lakes.

The Ogwer next flows through marshy ground for a distance of
three-quarters of a mile, and then swells out into a lake, Llyn Ogwen
(Pl. VII, Fig. 1). This sheet of water, nearly a mile in length, is
broadest at its eastern end and narrows towards the west, where its
waters,escape through a gorge. The total area covered by it is
approximately 456,400 square yards, but in spite of its size the lake
is remarkable for its extreme shallowness, the water nowhere.
attaining a greater depth than 10 feet. It is also noteworthy that
it is deeper at the eastern end than at the west, the gradient of the
lake-bottom sloping towards the east.2 It is a picturesque lake,,
surrounded as it is by noble mountains (Pl. VII, Fig. 1) that form the
highest group in North Wales, and is apparently landlocked. On its.
northern banks rise the crags of Carnedd Dafydd, with a perfect cwm
facing east near its summit, and in which les the small lake

1 “ Features of Alpine Scenery due to Glacial Protection’’: Geographical
Journal, 1910, pp. 310-39.
2 Jehu, op. cit., p. 440.

148 Henry Dewey—Land-forms in Caernarvonshire.

Ffynnon Lloer, from which a small stream, the Afon Lloer, flows
down to Llyn Ogwen. To the south it is flanked by a series of
magnificent precipices terminated by the serrated edges of Tryfaen
and Glyder Fach. There are many fine cwms along this ridge, all
facing north-east, and in one lies Llyn Bochlwyd.

The lower slopes of T'ryfaen and Carnedd Dafydd both bear record
of the thickness of the former ice-sheet in their roches moutonnées
and strie which extend far up their slopes, and also to the action of
frost and ice in their cwms, llyns, and moraines, but all these
features are still more perfectly preserved at the western end of
Llyn Ogwen.

The Holyhead road follows the side of the lake for a distance of
over a mile and at approximately the same level the whole way,
namely, a thousand feet above the level of the sea. A spur of
Carnedd Dafydd bounds the western end of the lake and is rounded
into smooth mammillations and roches moutonnées. It is seen in
Pl. VII, Fig. 1. The waters of the lake, however, flow across this
smooth rock-barrier in a low gorge and then suddenly plunge down
into a deep chasm. This feature will be described later in relation
to a similar one connected with it.

Llyn Ogwen lies on an upland plain; arising steeply from this
plain is a rock-step, deeply scored with glacial strize, through which
a mountain torrent, the Afon Idwal, has ripped a gorge; if this
torrent be followed, a second plateau is soon reached. It spreads
out in front of a ring of magnificent precipices that form the base of
Glyder Fawr and Y Garn and embrace the gloomy Llyn Idwal.
This plateau rests at a height of about 1,250 feet above sea-level and
is largely covered with strewn blocks derived from the almost
vertical walls of the precipices, and in part arranged as moraines.
Ramsay notes that moraines now skirt Llyn Idwal, the progressive
retreat of the glacier being marked on the western side of the lake
by four moraines arranged concentrically one within another. On
the south and on the east of the lake there are patches of moraine
matter, and other moraines dam back the waters at its northern end.
Other glacial features, such as blocs perchés, roches moutonnées, and
glacial striz, are conspicuous, the striz all being directed towards
Nant Ffrancon.

Professor Jehu! investigated the lake and its surroundings, and
notes that it is broadest at its lower end, whence the River Idwal
issues. The length of the lake is 846 yards, maximum width
340 yards, area of water 159,300 square yards, mean breadth
188 yards or 22 per cent of its length. He took eighty-one
soundings, which prove the bottom to be very irregular, in places
rauddy; but over a large part boulders of all sizes seemed to be
scattered about and interfered with the soundings. The greatest
depth registered was 36 feet in two places, the mean depth was
11 feet, while the greater part of the lake was found to be extremely
shallow, 57 per cent of the total area corresponding to depths under
10 feet. The deepest part of the lake lies close to its western shore.
Professor Jehu considers that Llyn Idwal was probably at one time

1 Op. cit.

Henry Dewey—Land-forms in Caernarvonshire. 149

much deeper, but is gradually filling up by rock-falls from the
neighbouring heights. A mass of drift crosses the valley at the foot
of the lake, and seems to be of sufficient depth to account for its
formation and disposes of the necessity for supposing it to be a rock-
basin. The configuration of the lake-bottom supports this view, for
there is no deep cup-shaped depression such as is found in other
lakes of North Wales, but an irregular floor with rocky knobs jutting
up here and there. Professor Jehu therefore concludes that the lake
is a barrier-basin with a floor that may have been modified by
glacial action.

Tur Vatuey-Sreps at RwarapR OagweEn.

Llyn Ogwen lies on a plain at 1,000 feet above sea-level. Llyn
Idwal les on a plain at 1,250 feet above sea-level, while Nant
Ffrancon extends as a long wide flat for a distance of 3 miles at a
nearly uniform height of 700 feet above the level of the sea. There
are thus three plains, rising one above another in tiers; the rise,
however, between each is not gradual, but abrupt. These features
are shown on the profile section, p. 150 (Fig. 1a), drawn to natural
_ scale, and in the view of Nant Ffrancon (Pl. VII, Fig. 2), where the
lower valley-step is seen across the top of the valley.

Between Llyn Idwal and Llyn Ogwen the step is steep, and the
river rushes down its face as a series of torrents, in places in shallow
gorges until it unites with the River Ogwen at Pont Pen-y-Benglog
to form the cascade known as Rhaiadr Ogwen. A fine view of the
chasm is obtained from near the bridge. After heavy rain the gorge
is choked with spray and the “ monotonous roar that fills the ravine’’.

Various hypotheses have been advanced to account for the origin
of such ‘‘ valley-steps”’ in glaciated countries. The two steps at
Rhaiadr Ogwen are certainly, in part at least, due to the harder
interbedded and intrusive igneous rocks that lie among the sediments,
and the absence of similar steps in Nant Ffrancon may be due to the
absence of igneous rocks in the rest of the valley.

The gorges cut by the Rivers Idwal and Ogwen at Rhaiadr Ogwen
have carried the drainage of the two upland plains into Nant
Ffrancon ; but the study of the topography of the locality indicates
an earlier drainage into the River Llugwy. This was suggested by
Brend, and the bathymetrieal survey of Professor Jehu at Llyn Ogwen
lends support to the hypothesis in that it proved the floor of the
lake to fall from west to east, i.e. in a direction opposite to the
flow of the water of the lake. This diversion of drainage was
brought about in glacial times when glaciers filled Cwm Idwal and
the plain at Llyn Ogwen. Sub-glacial streams then cut shallow
gorges in the valley, and these streams persisted when the ice
melted and carried off the drainage of the two upland plains into.
Nant Ffrancon.

Post-Guracrat Erosion.

The gorges thus initiated have since been deepened by the cascades
at Rhaiadr Ogwen. Similarly, on the west of the valley a small
mountain torrent has ripped out a beautiful gorge near Blaen-y-nant
Farm ; it is cut in bedded ash and is upwards of 40 feet deep. At

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150 Henry Dewey—Land-forms in Caernarvonshire.

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Henry Dewey—Land-forms in Caernarvonshire. 151

Rhaiadr Ogwen the gorge is not much deeper, and the amount of
post-Glacial cutting appears to be about 50 feet. Elsewhere in the
valley there is no evidence of a greater amount of post-Glacial
fluviatile incision, but another significant instance of a similar
nature is the gorge by the Salmon Pool near Pont-y-garreg. Here
the thick-bedded grits of the Lingula Flags are carried across the
valley as a barrier through which the Ogwen has cut a gorge with
vertical walls not 25 feet apart. At the same locality there are
three prominent terraces preserved, each about 30 feet above the
other and all smoothed andstriated byice. These were overwhelmed -
by the great glacier; but as this retreated up-valley the barrier
must have held back the waters that formerly spread out as a lake
and filled Nant Ffrancon (Pl. VII, Fig. 2). Subsequent erosion has
brought the base-level below that of the wide level tract of Nant
Ffranecon, and the Ogwen now rushes in a series of picturesque
cascades and torrents through this belt of country where the grits
occur. These grits strike straight across the valley and sweep
upwards to the west to form the precipices rising above Cwm
Graianog. They are intensely hard and coarse-grained rocks, and
under the microscope are seen to consist of rounded grains of quartz
with a subordinate amount of fresh plagioclase felspar and some
scales of white mica. The rock might be termed an arkose.

A similar amount of post-Glacial erosion is indicated at many
localities over a wider area, especially in that little visited and
desolate tract of moorland that les between the ridge forming
Carnedd Dafydd and Carnedd Llewellyn and the mountains near
Aber. - In this tract the rivers have here and there removed the
glacial detritus from their valleys, but the depth of the post-Glacial
valleys is seldom more than 45-50 feet. But the Afon Anafon
near Aber has cut a deep trough in debris and has led to a local
collapse of a huge scree below the mountain, while the great cliff
that remains appears to be.a contradiction to the other evidence.

Here, however, the effect of recent local denudation may be
noticed. In Cwm Coch near Blaen-y-nant Farm an enormous gash
has been rent through scree material by a cloud-burst. It is
upwards of 20 feet deep. Greenly! describes the effect of a similar
cloud-burst on the scree beneath the lower slopes of Carnedd
Dafydd where the road was swept away by the torrential waters.

The mode of occurrence of the glacial drift leaves little room for
doubt that the principal topographical features had been formed
before the coming of the ice. All the valleys examined indicate that
they are essentially pre-Glacial and that very little modification of
them has taken place in post-Glacial times. This subject will be
reverted to later and some evidence given in support of the views
expressed. In the meanwhile the glacial characteristics of the
Ogwen valley will be further considered.

Tue Cwms anv tHE Hanoine VALLEYS.

On the western side of Nant Ffrancon there are many typical
ewms, and it is significant that all of them face either to the east

1 GEOL. MAG., 1901, pp. 68, 69.

152 Henry Dewey—Land-forms vn Caernarvonshire.

or to the north-east (Pl. VII, Fig. 2). First is Cwm Bochlwyd,
lying between spurs thrown out from Glyder Fach and Glyder |
Fawr, and in which lie the sombre waters of Llyn Bochlwyd; this
forms a characteristic hanging valley with a mountain torrent ripping
its course down to Llyn Ogwen. Next comes Llyn Idwal in Cwm
Idwal, flanked by the grand precipices of Glyder Fawr and Y Garn.
Then from south to north follow Cwm-clyd, Cwm Cywion, Cwm-
goch, Cwm-Bual, Cwm Perfedd, Cwm-graianog, and Cwm Ceunant.
In most of these cwms there are relics of their own small glaciers,
- especially well seen in Cwm-graianog, and it is significant that the
change of slope marking the truncation of the spurs is practically
always at a height above sea-level of 1,250 feet; and further, this
altitude marks the limit of glacial strie incised by the great glacier.
Of Cwm-graianog Ramsay remarks: ‘‘ But in none of the tributary
valleys north of Llyn Idwal are the signs of a small glacier so
distinct as in Cwm-graianog below the steep slopes of Moel Perfedd.
It is a small craggy valley over half a mile in length looking across
Nant Ffrancon. On the east the felspathic porphyry of Moel
Perfedd rises in a rough peak, and on the west the great bare ripple-
marked strata of the Lingula grits dip towards the hollow at an
angle of 48° or 50°.

‘At the mouth of the valley above the steeper descent to Nant
Ffrancon, a small but beautifully symmetrical terminal moraine
erosses the valley in a crescent-shaped curve, that once passed from
200 to 800 yards up the eastern side of the glacier. On this side
almost every stone of the moraine is a fragment of the felspathic
rock of Moel Perfedd, havimg been shed from the edge of the glacier
by a part of the ice that had that mountain as its source. Further
west along the moraine, the material becomes mixed with fragments
of grit and slaty sandstone, and, by degrees, passing to the western
side of the valley, the moraine matter consists entirely of pieces of
the Lingula beds that form the crags of Carnedd-y-filiast. . . . In
Cwm-graianog the whole is formed of large angular loose stones
mixed with smaller debris. The largest of these lies on the top of
the moraine, from 450 to 500 feet above Nant Ffrancon. It. was
originally 11 yards long, 9 broad, and about 13 high, and when
entire must have weighed nearly 300 tons. . . . Inside the moraine
the bottom of the valley is covered with glacial rubbish and heaps of
loose blocks.”’ '

In marked contrast with these cwms is the even unbroken slope
that bounds the eastern side of Nant Ffrancon and forms the ridge
known as Pen-yr-Oleu-wen. But striz can be seen on the rocks
below Braich-du at a similar height to those on the opposite side of
the valley. These facts afford evidence of the maximum thickness
of the glacier that filled Nant Ffrancon. The present level of the
alluvial tract is 700 feet above sea-level, but the valley is partly
filled up with boulder-clay and peat, possibly together 40 feet thick.
The ice was therefore certainly not less than 700 feet thick. It
enveloped all the land lying at altitudes lower than 1,250 feet, for no

1 Op. cit., pp. 83, 84.

Henry Dewey—Land-forms in Caernarvonshire. 158

arétes or cribs occur below that level, althongh they commence
immediately above.

These cwms are shown in PI. VII, Fig. 2, and their bases are all very
closely at the same altitude. This also corresponds with a plateau
feature above Bethesda and lying between Nant Ffrancon and
Clegyr. It is marked on the old map as a Turbary plain, but a lake
used as a reservoir now occupies most of the area formerly filled with
peat. ‘This broad moor is covered with drift and extends into the
valley of Marchlyn-mawr, while remnants of it are seen on the
opposite side of the Ogwen Valley near Afon Berthan, the Llafar, and
Afon Caseg Valleys. The feature is conspicuous at Moel Rhiwen
and near Douglas Hill.

In Nant Ffrancon the foothills of the mountains are deeply
striated, the strie pointing down stream; but these do not extend
above the level of the lips of the cwms.

Now all these features are attributed by the two schools of
glacialists respectively to the protective or the erosive function of
glaciers. The views, however, held by the one school are not
entirely contradictory to those of the other, but rather are supple-
mentary, i.e. those who ascribe to glaciers a protective function do
not exclude thereby erosive action of ice nor the backward stoping
of Bergschrund.

Thus Garwood admits the power of ice to erode, but also insists
on its efficacy under certain circumstances to act much as a bed of
clay would in protecting underlying rock from disintegration due to
the expansion and contraction of freezing water. In cwms the
gently -sloping valley heads are thus protected, while the higher
slopes are exposed to sun-heat and frost, especially in such cases
where the main glacier has retreated up its valley leaving tributaries
above the ice-line, in cwms receiving only small amounts of sun-heat
‘ on account of their north-easterly or easterly prospect. The almost
invariable rule of the cwms facing these and the absence of cwms
facing other directions strongly supports Garwood’s contention.

Tart Lower VaLiry oF THE OGWEN.

Between Bethesda and Bangor the Ogwen flows rapidly through
a deep and well-defined valley, which everywhere bears record of
glacial activity. The strongly moutonnéed rocks and deeply incised
striz are well preserved on the Bethesda slates near the village and
at the mouth of Nant Ffrancon, and at first the wide valley appears
to be free from drift deposits. Closer examination, however, proves
that this supposition is incorrect. To take two or three instances
only among many others, there is first the pit near Felin hen Station,
where upwards of 20 feet of boulder beds are exposed in a low hill-
side rising gently from a plain; while near the Halfway House the
lower slopes of a hill have been cut into, and the open pit exposes
more than 30 feet of similar boulder material. Elsewhere in the
area described low hills rising above the general plain level are seen
to consist of boulder-clay or sand, and these occur at various heights
above sea-level and down to and below low-tide mark, as near Penrhyn
Castle and at Beaumaris on Anglesey. Old valleys are partially

154 Henry Dewey—Land-forms vm Cauernarvonshire.

infilled with glacial deposits, and the plain and even the tops of hills
carry boulder beds. This evidence clearly indicates that the wide
general topography as it at present exists was for the most part
produced in pre-Glacial times, or at least when the spreads of glacial
detritus were laid down.

-

Tur 480 Foot Prain.

By keeping to the Ogwen Valley, however, a wrong impression of
the topography of Caernarvonshire is gained, and it comes as
a surprise to find, after climbing the hills, not a mountain region,
but a widespread area of gently undulating ground, p. 150 (Fig. 10),
where the hills are truncated into flat-topped ridges. On turning
towards the mountains it is further seen that this plain abuts against
their masses at an even level for many miles, while they rise from it
like islands from the sea.

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Tia. 2.—The ‘‘ Pliocene’’ plateau near Bangor. The plain terminates at
a height of 430 feet above sea-level, the mountains near Snowdon rising
abruptly from it. Its wide expanse is clearly seen in this sketch.

The above picture (Fig. 2) shows a view of these features takén
from the Bangor Golf Links and looking towards Nant Ffrancon,
where the wall-like mass of Glyder Fawr is seen bounding the valley
at right angles to it.

Another sketch (Pl. VII, Fig. 3), made near the Anglesey
Monument, shows similar features of a country diversified into
a series of parallel ridges with flat tops, terminating against the
mountain mass. In the area bounded by the Ogwen Valley, the

Padarn Valley, and the mountains there is scarcely a hill that rises
above this plain, although much of the ground is lower and there are
several deep river- valleys. The amount of erosion that has taken
place since the uplift of the plateau is marked by the Menai Straits,
which attain a depth of 70 feet below sea- level, while the Afon

Henry Dewey—Land-forms in Caernarvonshire. 155.

Cegin, the Afon Seiont, and the Afon Cadnant have each cut valleys
several hundreds of feet deep in the plateau.

Some agency has truncated all the land at a common level, and
inspection of the Ordnance map shows that level to be 430 feet above
that of the sea. There are, however, a few hills that rise above this
plain, and on almost every one of them a hill-fort consisting of
circular earthworks is preserved. To mention some examples, there
are the two camps situated respectively on the west and the east of
the Padarn Valley near Cwm-y-glo;. the fine hill-fort at Pen-y-
ddinas by Llanddeiniolen, the Castell near RKhiwlas, the Camp by
Tregarth, and another at Rhiw Goch. Similarly on Anglesey? the
earthworks are placed on the few hills that rise above 400 feet and
are there described as various Mynydds.

But this plain does not extend far to the east of the River Ogwen,
as the mountains run out to the coastline near Aber. Its margin is
rendered obvious on the map by the crowding together of the
contour-lines above 400 feet, but it is still more conspicuous in
Nature. Fig. 1d, p. 150, is drawn to the natural scale, and shows
the abrupt change of slope at the base of the mountains.

It is difficult to follow the edge of the plain across country, because
there is no road running parallel with it, but the feature is distinctly
seen even from a distance. Nevertheless, when the margin is
reached the ground is usually boggy and often covered with saturated
‘peat, with small streams soaking through it. Tregarth village is
built in part on the plain, and here the rise to the adjacent
mountain is marked by several boggy meadows. But perhaps the
feature is best seen in the country lying between Llanddeiniolen and
Moel Rhiwen, especially near Waen, where hillocks composed of
boulder beds rise above the general plain to form dry patches of
arable land in a region generally wet.

The feature cuts straight across the mouth of the Llanberis Valley
and does not run up into that valley, a fact that implies the formation
of the valley subsequently to that of the plain. It then extends in
a general south-westerly direction near Llanrug, where Garth is
situated on an isolated hill rising out of the plain. Thence by
Groeslon and Pen-y-groes it spreads toward the Lleyn Peninsula,
but I have not traced it in detail much beyond the valley of the
Seiont.

Such a sudden change of topography suggests a different degree of
hardness of the rocks underlying the two areas, but reference to the
geological map (Sheet 78) shows that in both areas similar rocks
occur. These consist of slates, grits, limestones, and shales with
bedded and intrusive igneous rocks. In the one area all of them
have been planed down to a common level; in the other differential
hardness has led to variety of sculpture.

Of late it has been the fashion to adopt American terminology in
describing upland plateaux and also to reject the sea as the agent
which has produced these features. In some cases the term
‘‘peneplain”’ may be applicable, but it is difficult to imagine why
subaerial agencies should cease operating along a purely arbitrary

1 See Mr. Greenly’s forthcoming Memoir on Anglesey (Mem. Geol. Sury.).

156 Henry Dewey—Land-forms in Caernarvonshire.

line, leaving parts of a district immune from attack and reducing at
the same time adjacent areas of similar geological formation and
structure to a featureless plain. In the ‘present instance I reject
the hypothesis of subaerial erosion. Marine erosion proves its
capability of levelling rocks of all degrees of hardness, as anyone
familiar with coasts bounding the Atlantic must acknowledge. The
Cornish coast is a convincing instance of the sea’s power to produce
level tracts, and moreover lands of all degrees of hardness ultimately
yield and become reduced to the limit of erosion. Such a marine
plain is seen at low-water spring tides near Bude, where a quarter of
a mile of bevelled rocks are exposed. They consist of alternate beds
of hard sandstone and slate, but all have been planed down to
a uniform level, or rather a long gentle slope towards the deeper
waters. The tide in rising suddenly covers this plain, and is apt to
cut the unwary off from retreat. On this coast it is always well to
remember that—
Far back through creeks and inlets making
Comes silent, flooding in the main.

There can therefore be no valid reason to offer why the sea did not
similarly operate on this plain in North Wales.

It is more difficult to determine the period when this reduction
occurred; the fact that the feature terminates in both Cornwall and
in North Wales at precisely the same height above sea-level suggests
that the two plains are contemporary, whatever their geological age
may be. That in North Wales the plain is pre-Glacial is proved; in
Cornwall there are strong reasons for supposing it to be of Pliocene
age. We are then perhaps justified in accepting as of the same age
the North Welsh plain at this level.

In both districts, however, there are wide tracts at lower levels,’
notably that at 200-300 feet above Ordnance Datum, but in both
these do not occur above 480 feet, with the exception of those.
already mentioned at 700, 1,000, and 1,250 feet respectively. The
lower plains may also represent other marine plains or peneplains,
but with these I am not concerned. The point to be emphasized is
the occurrence in both districts of a plain which does not rise higher
than 430 feet above sea-level.

Before concluding I wish to express my thanks to Mr. Greenly for his
kindly advice and suggestions made during the writing of this paper.

ConcLusions.

1. Glacial phenomena as expressed in land-forms have long been
known in North Wales. In the valley of the Ogwen the whole series
of land-forms characteristic of glacial topography are represented,
namely, the lakes, cwms, hanging valleys, valley-steps, and arétes ;
and in addition the evidence of former glaciers as represented by
moraines, roches moutonnées, and blocs perchées.

2. There is sufficient evidence to show that the major land-forms
are pre-Glacial and that post-Glacial erosion is comparatively slight.

3. Pre-Glacial erosion had sculptured a former upland plain into

1 See Ramsay, Geology of North Wales (Mem. Geol. Surv.), p. 269; also

Quart. Journ. Geol. Soc., 1876, p. 116; also Greenly, Rep. Brit. Assoc.
Bradford, 1900, p. 737.

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Prate VII.

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LAND-FORMS CARNARVONSHIRE.

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Lieut. Serivenor—Origin of Clays and Boulder-clays. 157

a region diversified with ridges and valleys, with its own drainage
system independent of a mountain drainage system adjoining it.

4. This upland plain terminates at a height of 430 feet above
sea-level and is of widespread occurrence.

5. A similar plain forms conspicuous features in Cornwall and in
Devon, and terminates in those two counties at precisely the same
height as that of North Wales. This plain is not more recent than
Pliocene, but may be older.

6. There is evidence that these upland plains of North Wales and
Cornwall and Devon were formed contemporaneously and by marine
erosion.

EXPLANATION OF PLATE VII.

Fie. 1.—Llyn Ogwen. The view shows the landlocked waters of the lake
with the amphitheatre of great mountains encircling it. In the middle
distance is the low barrier through which the waters escape in a gorge.
It is deeply grooved by glacial striz, which also extend up the lower spurs
of Carnedd Dafydd to the right. On the left of the barrier rises a valley-
step that separates Llyn Idwal and its plain from Llyn Ogwen. ‘The
mountains in tbe background are Y Garn and Foel Géch. On both of
these mountains are characteristic cwms, all facing to the north-east.

Fie. 2.—Nant Ffrancon, looking south. The valley-step igs seen across the
head of the valley, over which the waters of Rhaiadr Ogwen fall. In the
middle distance is a “‘roche moutonnée’’; on the right are cwms and
arétes, while the lower slopes of the mountain show truncated spurs.
The foreground consists of glacial detritus and peat which has accumulated
on the floor of the valley. The mountains in the distance are Y Glyder
Fach and Y Glyder Fawr; on the right are Y Garn and Foel Goch.

Fie. 3.—The ‘‘ Pliocene ’’ plain of North Caernarvonshire. This view is taken
from Anglesey and shows the extensive upland plain diversified with deep
valleys and flat-topped hills. Im the foreground lies the Menai Straits,
here about 70 feet deep. The Snowdon range of mountains forming the
background rise abruptly from the plain.

Jl.—Tue Orem or roe Crays ann Bourper-ciays, FrpErarrp
Matay Srarrs.!
By Lieutenant J. B. SCRIVENOR, M.A., F.G.S.
INCE the earlier edition on the geology of Kinta was written
k-) much fresh evidence has been brought to light on the subject of
the origin of the clays and boulder-clays and the tin-bearing deposits
showing bedding at Gopeng. ‘The effect of this evidence has not

1 The subjoined note which accompanied this article from the author to the
Editor of the GEOLOGICAL MAGAZINE was received on January 8, 1918, when
Mr. Scrivenor was leaving for France :—

Sir,—With reference to Mr. W. R. Jones’s paper in No. 287 of the
Quarterly Journal of the Geological Society, pp. 165-94 (isswed November 23,
1917), on the ‘‘ Secondary Stanniferous Deposits of the Kinta District’’,
I shall be grateful if you will publish the following article on the “‘ Origin of
the Clays and Boulder-clays’’. This was written before I left the Malay
States and before I had seen Mr. Jones’s paper. I note that on p. 176 of his
paper the latter says that at Kacha, Tambun, Lahat, and Papan, clays and
boulder-clays can be traced into partly decomposed phyllites exhibiting distinct
foliation. Ido not remember Mr. Jones offering to show me these occurrences.
The section at Siputeh mentioned in the fourth paragraph of p. 177 is that
described by myself, and I took Mr. Jones to the mine to see it.

J. B, SCRIVENOR.

R.E. DEPpoT, BALDOCK, HERTS. January 7, 1918.

158 Lieut. J. B. Scrivenor—Origin of Clays and

been to lessen the objections to the glacial hypothesis put forward
by myself, but at the same time it still remains the only explanation
that meets the facts in a way that can be called at all satisfactory.
It may be that long acquaintance with the subject has made me see
difficulties in the way of other explanations where in fact no
difficulties exist, and my position regarding the question is some-
what akin to that of a doctor versed in tropical medicine who once
informed me that the result of many years study of the etiology of
bert-berv was that he felt he could raise fatal objections to any theory
that had been proposed. I have not seen sufficient reason as yet,
however, to change my views on the subject of these clays and
boulder-clays. Certain sections to be noted later militate against
a glacial origin, but the evidence of these deposits, including those
showing bedding at Gopeng, being older than the granite of the Main
Range is stronger than it was before. In the following paragraphs
I will attempt to give briefly a statement of the points for and
against all possible explanations of the peculiarities observed in
these important sources of tin-ore.

It will be convenient to consider first the deposits that show no
bedding. These occur both on the west and on the east of the
Kinta River, and are especially well developed in the vicinity of
Siputeh and Pusing. The problem regarding them may be stated
thus: Are they the result of bedded rocks being broken up and
completely disorganized owing to the limestone underneath them
being dissolved away and so producing a general sinking movement
in the overlying material; or were they originally laid down as
unbedded clays with irregularly distributed boulders?

When work was commenced in Kinta the former of these two
explanations commended itself, and I think that anyone examining
the evidence cursorily would come to the same conclusion. In
a paper on the tourmaline-corundum rocks of Kinta (Quart. Journ.
Geol. Soc., Ixxvi, p. 448, 1910) I gave as my opinion that they were
derived from rocks associated with schists over limestone, probably
chert and silicified ihmestone, and I may also remark in passing that
on p. 488 I referred to the corundum found in the “ alluvium”’ at
Pulai and elsewhere.

At that time, however, it was thought that there were two
occurrences of these rocks known to be in situ, i.e. in the position
where they were originally deposited before alteration, but in one
case mining operations proved this not to be the case, while in the
other the mass of rock, close to the Siputeh bridle-path from Batu
Gajah, might have been a huge boulder. It is now completely
hidden by mining silt.

Bedding that is a division of a mass of rock into clearly defined
strata of more or less different composition has never been seen in
these clavs, but in a few cases a faint trace of lamination has been
seen. ‘This, however, might be the effect of pressure on unstratified
clay. The tourmaline-corundum rocks are hard, the clays are soft.
What is required to prove that the former are derived from a con-
tinuous bed or beds intercalated among softer beds is a section
showing some sign of it, and as yet no such section has been found.

Boulder-clays, Federated Malay States. 159

Another possible suggestion regarding these boulders is that they
are analogous to ‘‘core-boulders’”’ of granite; that they are portions
of beds rich in corundum and tourmaline that have resisted
weathering. It is known that the containing clay is sometimes
very rich in soluble alumina, derived, it is believed, from minute
pieces of tourmaline-corundum rock by the alteration of the
corundum, but where clearly bedded rocks are exposed, as at
Kacha, Redhills, and near Batu Gajah, there is, with one exception,
no trace of the pecular structure of these rocks. That exception is
a rock found near Redhills, containing traces of Radiolaria which
may have been the foundation of some of the bodies in the
tourmaline-corundum rocks.

It is felt now that the previously held views regarding the origin
- of these rocks will not meet all the facts, and the objections are well
exemplified at Redhills and Kacha. On the Redhills and Pusing
Lama mines large boulders of tourmaline-corundum rock are found
in tin-bearing clay.

At Redhills hmestone was found underneath the clay. On both
mines, but on higher ground, soft, weathered, bedded rocks are
found. On Pusing Lama a section was once uncovered, showing
small tin-veins in tourmalinized shales. If the clay with boulders
of tourmaline-corundum rock is simply the shale disorganized over
sinking limestone, then the shales should contain the tourmaline-
corundum rock too, but, as far as I am aware, they do not. Over
the clay these boulders are numerous, but over the shales they are
replaced by masses of ironstone formed at and near the surface
(Malayan ‘‘laterite’’). Here, then, is what seems to be a fatal
objection to the clay being disorganized shale.

At Kacha the evidence on the old mine worked formerly by
Towkay Ong Siew is somewhat different. On the lower part of the
mine there are clearly bedded and somewhat sandy rocks with
intrusions of aplite. Some of the hardest material has been
examined, and nothing was found of the structure of the tourmaline-
corundum rocks. On the other hand, on the high ground that has
been extensively worked by ground-sluicing, there are abundant
tourmaline-corundum boulders, some of which can be seen in situ,
- andno bedding is to be seen now. If the bedded rocks on the lower
level retain their bedding, and if the rocks on the higher level were
once bedded, surely the conditions there are more favourable for the
preservation of that bedding, seeing that the strata on the top of the
hill are less likely to be disorganized by sinking over limestone as it
dissolves away than those at the base.

Once on Pusing Lama a thin bed of clay with boulders was seen
under shales, and at Kacha evidence was seen of alternation of shale
and clay with boulders, but as these sections cannot be seen now
they can hardly be cited as evidence.

Another strong objection to the theory of the clay being dis-
organized shale is its condition at the junction with granitic rocks.

On the Pusing Lama mine a lode was discovered that became well
known. It was at the contact of a soft granitic rock and soft clay
with boulders of tourmaline rock and powdery tourmaline evidently

160 Ineut. J. B. Scrivenor—Origin of Clays and

of a secondary nature. Tourmaline-corundum rock occurred near
by. The earlier work on this lode was underground, but now there
is an open-cast mine on the junction. On the one hand is a granitic
mass rich in kaolin and traversed by tourmaline veins, one
sufficiently well preserved to show a small fault; on the other, deep-
red clay in which an apophysis of granitic vein-material was once
seen, itself traversed by tourmaline veins. One may argue that
away from the junction bedded shales and harder rocks might be
disorganized over limestone so as to simulate boulder-clay, but at
the granite junction, where the granitic rock is equally soft and
contains clearly defined tourmaline veins, the bedding of soft and
hard rocks ought to be preserved. But it is not preserved, and the
inference is that it never existed.

But away from the junction also there has been evidence against °
the clay being disorganized shale. At least one vein of ore has
been worked open-cast with a course that could be easily followed.
How could this be preserved if the clay and boulders are broken-up
hard and soft strata ?

Even more striking is the evidence at Tekka and Gopeng, where
there are good exposures of the junetion between granitic rocks on
the edge of the Main Range mass and clay at Tekka, while on the
Ulu Gopeng portion of Gopeng Consolidated is a junction with
schists.

These schists are exposed on old workings at the top of
a steep hill overlooking the town of Gopeng. They are clearly
bedded and dip at a very high angle to the west. Sandy phyllites
are common; tourmaline-schist and actinolite-schist occur. Both

rown and white mica occur. The soil above them contains
ferruginous masses showing the structure of the schists they have
replaced on weathering. Quartz veins are abundant.

The clay at the junction with the granite on the Tekka Ltd. mine
and on mines further to the south should, if it is the result of the
extreme weathering of schists, still show some resemblance to the Ulu
Gopeng sections. The clay cannot be schist that has become a dis-
organized mass through movement because at the junction tourmaline
veins have been traced into it; and moreover there are other veins
found sometimes parallel among themselves, but sometimes brecciated
by movement, which are the effect of alteration by the granite.
Under the microscope these veins are found to consist chiefly of
white mica and fluorite in minute particles. In some veins
corundum, spinel, and blue tourmaline occur also; and it is
significant that whereas the tourmaline in the Ulu Gopeng schists
is brown, that in the clay is blue, and of a shade pale enough to be
distinctly recognizable in a hand specimen. Only a few grains of
brown tourmaline have been obtained by washing a quantity of clay.
Moreover, the clay at the junction shows lamination with bright
colours, described elsewhere in this Magazine, which has no counter-
part in the Ulu Gopeng section. If therefore we assume the clay to
be schists like those at Ulu Gopeng weathered so as to lose all trace
of bedding we have to explain why alteration by the granite
produced such different results on the same material. The granite

Boulder-clays, Federated Malay States. 161

must have been intruded when the bedded rocks were fresh and
unweathered deep below the surface, and the only solution seems to
be that the clay now exposed on the surface never resembled the Ulu
Gopeng schists.

In the earlier publication a section was described on the Kramat
Pulai mine. ‘This was one of those rare cases where I had another
observer (Mr. W. Rh. Jones) to check the accuracy of my sketch
before the section was destroyed. Reference to it will show that if
the boulders are portions of a continuous hard bed broken up the
kaolin vein must have been broken up too, which is not the case.!

‘“‘Laterite’’ was mentioned above. This has an interesting bearing
on the question under discussion. When shales and schists are
weathered at the surface, generally, but not always, these masses
of ironstone are formed, and as the iron is gradually deposited
along bedding-planes and joints the masses exposed at the surface
frequently preserve the structure of the rock they replace and are
themselves a guide to.the nature of the country rock. In mining
operations these ironstone growths often give much trouble, as for
instance at Bruseh, and if the Kinta clays and boulder-clays were
weathered shales or schists one might reasonably expect to see
numbers of them in the soil or in mines where the soil has been
worked away. But such masses do not occur, as far as I know.
The clays are sometimes hardened by the deposition of iron, but
there is no shaley or schistose structure preserved. On the other
hand, where clearly bedded rocks occur, as at Redhills and near
Batu Gajah, ironstone replacements do occur, and in ditches near the
latter locality one can see how the ironstone is gradually deposited
as the shale weathers away.

Another point to be considered is this. If we conclude that the
clays are formed by shale, etc., sinking over limestone as it dissolves
away, we should first be sure that there has been sufficient alteration
in the level of the limestone to produce the result. It is impossible
to obtain precise information, but although there are doubtless places
where deep cavities have been hollowed out, there is some evidence
pointing to the general lowering of the limestone surface having
been slight.

Usually the limestone surface is a mass of pinnacles, but for some
time there was exposed, in the bottom of a mine at Tekka, Sungei
Raia, a large and almost flat platform of limestone that seemed to be
the original surface. Where the platform ended there were pinnacles
as in other localities. Again, at Gopeng, under the Gopeng Beds,
which show stratification, there is a limestone floor. This shows as
much irregularity as the limestone floor elsewhere, but the beds
above have retained their stratification, except immediately above
the soluble rock, where, however, a disorganized pebble-bed, if that

1 Mr. Jones now seeks to explain this vein as an effect of different colora-
tion in the clays, but if the Kramat Pulai vein can be thus explained the same
holds good for all the kaolin veins. I am quoted as describing a case at Pusing
Bahui which Mr. Jones says is similar, although he did not see it. It was, as
a matter of fact, different from the Kramat Pulai vein in that it had no sharp
boundaries and did not consist of kaolin.

DECADE VI.—VOL. V.—NO. IV. 11

162 Lieut. J. B. Scrivenor—Origin of Clays and

be the correct interpretation of its peculiarities, can be traced into
clearly marked strata. If these deposits at Gopeng retain their
bedding, why do not the others do so also if they are only weathered
shale and schist ?

Some mines have afforded exceptional facilities for studying deep
tin-bearing deposits, namely the Tronoh and Tambun mines.
The Tronoh mines contain shales and rich tin-bearing clay, and the
question is whether the latter are the shales weathered and broken
up over dissolving limestone or a distinct formation. It might be
argued with reason that taking this mine alone the former is the
better explanation and that the tin-ore was introduced by granitic
intrusions along the fault. I find it hard, however, to adopt this
view in its entirety. On the west are good sections of bedded shale
and quartzite, and I am informed that they carry only a little tin,
although granitic intrusions occur and also quartz veins, in one of
which wolfram has been found. Going eastward one comes suddenly
on clays without bedding, but with pebbles in some quantity and
very rich tin-contents. If the pebbles are derived from the harder
bedded rocks on the west and the quartz veins one would expect
them to be of greater size and more angular; and, moreover, seeing
that granitic intrusions occur in the bedded rocks it is difficult to
explain the comparatively large amount of tin-ore in the clay if it
all comes from granitic intrusions also. It might, however, be
suggested that the rich ore is derived from a long lode in shales,
now broken down to clay. I once saw a section in a small mine to
the south of the Tronoh Ltd. mine that might have been thus
interpreted, but nothing could be proved, and at the present time
there is nothing visible supporting the view. Nevertheless it may
be that some such interpretation as this is the correct one, and weak
points in the theory that the clay is a distinct formation overlying
the limestone are that nothing is known of it to the east underneath
the sand and masses of vegetation where the limestone rises nearer the
surface, nor has anything been proved concerning the presence of
tin-bearing clay under the bedded rocks on the west.

In Towkay Chung Thye Phin’s mine the distribution of the ore
is suggestive of a lode. On one side is the crystalline iimestone,
coming near the surface of the ground. On the other side is a steep
bank cut in the shale and quartzite showing innumerable little
stringers of kaolin and veins with tourmalinized shale on either side.
The ore-bearing clay occurs along the junction of the limestone and
shale and quartzite. In the portion of the mine nearer the Tronoh
Ltd. mine it is a narrow band of a few feet in width only. In the
gut in the centre of the photograph it is said to die out altogether.
Beyond it opens out again.

In the Tronoh South mine again the run of the ore suggests
a lode rather than a detrital deposit; but in all these Tronoh mines
there are objections hard to dispose of if we are to regard the
‘‘Tronoh lead”? as a weathered lode. In the first place, on the
west wall of the mines the effect of emanations from the granite is
seen in the tourmalinization of the shales bordering the small veins.
The shale is hardened and charged with minute crystals and grains

Boulder-clays, Federated Malay States. 163

of brown tourmaline. I have not seen anything like it in the rich
tin-bearing ground.

Again, in the Pusing neighbourhood veins have been found and
worked in clay just as soft as the Tronoh pay-dirt. They were
probably connected with the granite by fissures through the lme-
stone. In one case the vein was at a contact of granitic rock and
clay. But these veins preserved their identity as veins. There was
no mistaking them for anything else. At Tronoh, on the other
hand, the tin-bearing ground strongly resembles, if it is not,
a detrital deposit. Ifit were a broken-down lode we would expect
to find at least some trace of an ‘‘iron-hat”’ containing tin-ore,
lumps of hardened shale, with tourmaline, and large masses of tin-
ore. I have already mentioned the only section that I can remember
as even suggesting a lode. A hard mass with quartz seen lately in
the Tronoh Ltd. main lumbong also looked as though it might be
evidence of a lode, but the tin-ore was stated to be all to the east of
it, and it was only a weathered quartz-vein at the edge of the shales.

At the North Tambun mine one could see, early in 1916, soft ~
shales showing distinct bedding lying on the limestone and unbedded
clay rich in tin-ore hard by.

In Towkay Leong Fee’s mine at Tambun highly inclined bedded
rocks lie side by side with clay very rich in tin-ore. The latter
sometimes shows a trace of lamination, but I have not seen any
section where bedded can be traced into unbedded rocks. They.
appear to be distinct, but one of the Perak mining community who
has had a long experience of the mine holds the view that the clays
are the-bedded rocks very much weathered, and tells me that in the
latter good tin-values have been found. In the North Tambun
mines the-shales retain their bedding immediately above the lime-
stone, and it is difficult to understand why in this and in Towkay
Jeong Fee’s mine the bedded rocks have retained their bedding if
the others have lost it, seeing that both are equally soft and the
position of the limestone is such that one cannot help expecting it to
extend under the bedded rocks.

At New Tambun also the bedded rocks occurred in qiixtaposition
to the clays. The former were traversed by numerous small kaolin
veins. They yielded a little tin-ore throughout, whereas the clay
was comparatively rich. No lmestone was met with below the
bedded rocks.

In the Tronoh and Tambun mines, and also elsewhere, it might be
argued that in addition to the disturbing effect of the limestone
surface being lowered, the bedding of shales and schists has been
destroyed by the media that brought the tin-ore; in fact, this view
was put forward during a discussion on a paper read in Ipoh some
years ago. This would account for the greater quantity of tin-ore
in the ‘clays, but it is difficult to reconcile the theory with observa-
tions elsewhere.

In Intan, in Upper Perak; at the Ulu Gopeng mine; at Bruseh,
in Batang Padang; at Jeher, and near Tanjong Malim; and at
Pantai, near Kuala Lumpur, bedded shale and quartzite have been
invaded by tin-bearing media on a large scale, but I do not remember

164 Ineut. J. B. Scrivenor—Origin of Clays and

anything that supports the explanation put forward above. In
every case the bedding is clearly preserved, although the rocks
are soft.

Another possibility might be put forward. When some limestone
dissolves away a residual mass of insoluble impurities is left behind.
Are the clays and boulder-clays simply the residue left behind as the
limestone surface was lowered by solution? If the Kinta limestone
were impure this would account for much, but it would not account
for the beds with boulders of granite at Gopeng, and I think that
a fatal objection to it is that analysis shows the lmestone to be an
exceptionally pure carbonate rock. Analyses by Mr. C. Salter of
two typical specimens of limestone from near Menglembu gave the
following results :—

No. 1. No. 2.
per cent per ceut
Si O2 ; 3 ; ; +27 +26
AloO3 . ; ; é -26 +26
Feo 03 O O 5 4 -13 -09
MeO bs etek hen nie 0 3-75
Ca O : : ; . 64-50 51-80
C Oz . : : . 44-25 44-892
100-71 100-98

At the Tekka granite-junction the veins containing fluorite and
.the blue tourmaline veins suggest association with limestone; the
fluorite because it is calcium fluoride, the tourmaline because similar
tourmaline has been found in limestone on the Tekka Ltd. mine and
at Siputeh. But I do not think that anyone who has examined the
crystalline limestone and the clay at ‘'ekka could conclude that the
latter is the residual impurity of the former. If it were, and if
the veins were originally encased in limestone, the latter could not
possibly retain their course as veins now, because the diminution of
bulk of the containing rock would be enormous.

Finally, it may be said in favour of the clays and boulder-clays
having been deposited as clays and boulder-clays that in Sarawak
there have been exposed, in the gold-mines of Bau and Bidi, many
sections of shale over limestone, and generally, as far as I can
recollect, the bedding in the latter was distinctly preserved, although
the limestone had been attacked by water and carved into irregular
pinnacles just as much as in Kinta.

If the clays and boulder-clays were laid down as such the only
explanation of their peculiarities that can be adduced is that they
are of glacial origin. The evidence against this and against the
deposits being in their original condition must now be given.

The first objection to the glacial theory is that on the west side of
the valley boulders of different rocks are not mixed up as they
usually are in boulder-clay. The tourmaline-corundum rocks are
not mixed with boulders of granitic rocks. On the Siputeh Ltd.
property I have not seen any tourmaline-corundum rocks, although
in the Pusing Bharu mine they were very abundant, and have also
been seen at Siak. On the other hand, in the Siputeh mine are
abundant boulders of tourmalinized quartzite with tin-ore and

Boulder-clays, Federated Malay States. 165

boulders of quartz. Some years ago one or two granitic boulders
were found in this mine, but the great majority are those just
described, and in 1914 a section was laid bare in the tributor’s mine
that affords the strongest evidence against a glacial origin that has
been found. The section is in a big open-cast mine. On the near
side of the mine there is a high limestone wall and lignite. The
limestone extends to the bottom of the mine, which is about
120 feet deep, and above it, on the far side, is a section showing
boulder-clay on the left, and in the centre and on the right shale
and quartzite very much disturbed. About the same time that this
section was first seen a quartz-vein was exposed in the limestone at
the bottom of the mine, and, as the boulders in the clay are all quartz
or tourmalinized quartzite, the’facts point to the boulder-clay being
much disturbed quartzite and shale beds, together with a quartz-
vein, completely disorganized in a deep cavity in the limestone.

This section is the only instance of a boulder-clay being exposed
in close proximity to bedded rocks from which the boulders could be
derived, but the same section showed a further point that is difficult
to understand. On the left of the section and some yards away from
the bedded rocks were two elongated patches of clay rich in
tourmaline. These might possibly represent portions of the bedded
rocks rich in tourmaline, but their form suggested that they were
the result of the production of secondary tourmaline in the clay,
in which case the formation of the boulder-clay must have been
pre-granitic. This, however, is by no means certain, and the
patches cannot be taken as an objection to the clay and boulders
having been derived from the shale, quartzite, and quartz-vein at
some time. In this mine one must conclude that the boulders are
not of glacial origin, but are the remains of a tin-lode in shale and
quartzite overlying limestone.

Another piece of evidence obtained since the earlier edition was
published concerns the huge boulders of quartz in the Kinta
Association mine at Tanjong Rambutan. I have been informed that
at one period during the work a section of a big quartz-vein was
exposed from which the boulders could have been derived. I did
not see this section myself.

On the Tekka Ltd. mine, and in the sections to the south, where
the clay is in contact with the granite, there is another point that
must be mentioned. There are no boulders of any size to be seen
near the granite. For conclusive evidence of the clays being glacial
one requires boulders at the junction with the granite. They were
found in the Kramat Puali section, however.

The doubt concerning the origin of the tin-bearing clay at Tronoh
and Tambun can be cited against the glacial theory.

The absence of striz on boulders is also against this explanation,
but with rocks so weathered as these are, striae cannot be expected,
if they ever existed, except in the case of boulders of corundum or
tourmaline-corundum rocks. Nothing has been found that I can
regard unreservedly as glacial striae. A glaciated pavement of
limestone would be destroyed by solution.

Lastly, a powerful argument against the glacial theory is that with

166 =—s newt. J.B. Serivenor—Origin of Clays and

the exception of one section at Kacha mentioned earlier in this
chapter, but which cannot be seen now, the clays and boulder-clays
have only been seen resting on limestone. An exposure of them above
argillaceous or arenaceous rocks, or above any rock not soluble to the
extent that limestone is soluble, would remove all doubt of their
having been deposited as clays and boulder- clays, but no such section
can be pointed to.

The deposits that were described first as the ‘“Gopeng Beds” differ
from the foregoing in being in part stratified. Sections in the deep
excavations now being worked and other sections show that this
stratification is more distinet than was formerly thought to be the case,
but there are associated clayey beds with isolated boulders such as those
figured in the earlier edition (pl. v, fig. 8; pl. vii, fig. 3; pl. xvi, fig. 1),
and when that edition was prepared a glacial origin for them was the
only satisfactory explanation. Nothing further has been learned
about the first two cases illustrated by the figures, but other sections
have been seen where the boulder-beds are immediately above lime-
stone and could be interpreted as stratified beds disorganized by
sinking over limestone. This includes deposits invaded by kaolin-
veins. LTamstill uncertain that this view of pebble-beds being broken .
up and mingled with clay to simulate boulder-beds is the best. It is
insufficient to explain the section in which the big boulder figured in
pl. v, fig. 3, of the earlier edition occurred ; and the boulder figured
in pl. xvi, fic. 1, and other isolated boulders occurred on some of the
highest land.

Iti is difficult to believe that the corundum boulders found at Pulai
and on the Tekka Ltd. mine were deposited in their present position
by water-action. An alternative view to their being dropped from ice
into fine silt is suggested, however, by an exposure on Tekka which
has only recently been laid bare. In stiff clay overlying the lime-
stone corundum boulders were found in great numbers, many being
over 100 lb. in weight. When the limestone floor was exposed, it
seemed possible from the distribution of the boulders and the position
of some of them that they had formed a vein in the limestone. No
corundum could be found embedded in the limestone, but that, of
course, is not a fatal objection to there having been a vein, the walls
of which were dissolved away. Some of the corundum boulders are
angular, some well rounded. Like other specimens found at Pulai
and Tekka, the surface of the boulders is often pitted as though some
mineral intergrown with it had been dissolved away. I have not
obtained any evidence that it was calcite from the form of the cavities,
but that is possible.

In Selangor evidence has been found by Mr. Jones of faulting in
recent alluvium. Figures in the older edition show complicated
faulting in the deposits under discussion, and we have to consider the
possibility of the latter being recent alluvium faulted and in part
disorganized owing to the solution of the underlying limestone. It
is, I suppose, possible that faulting such as this could be produced by
such a cause, but it is unlikely ; and the evidence of the kaolin-veins
is directly opposed to the beds being recent. Accumulated observa-
tions of the form of the kaolin-yeins and their junction with the clay

Boulder-clays, Federated Malay States. 167

and pebble-beds point to their being intrusive The first vein I saw
was on Kinta Tin Mines Ltd. In 1908 the top of this vein was visible
and was sketched. In section it could be seen terminating in a thin
stringer of kaolin in the red clay. Later on the top was cut away by
a monitor and the vein exposed near the limestone. The junction
with the clay is shown in plate x of the old edition, as also another
junction between a kaolin-vein and the clay. In vol. Ixvii, 1912, of
the Quarterly Journal of the Geological Society, p. 149, fig. 4, a figure
is given of a kaolin-vein and a tourmaline-vein on Tekka Ltd.

The evidence of the form of the veins is strengthened by a case
where a kaolin-vein was found to be bordered at its junction with the
clay by a mica-tourmaline rock resembling a rock found at the junction
of granite and clay on Tekka Ltd. This rock is markedly different
from the body of the vein itself and can only be interpreted as the
result of metamorphism of the clay. The tourmaline is blue, as on
Tekka Ltd.

Sections of kaolin-veins have been exposed in beds high above the
limestone and also in excavations where they can be seen close to
limestone. In the latter one may see what I believe to be the effect
of the settling-down of the clay, pebble-beds, and kaolin-veins, as the
limestone dissolves. It shows itself sometimes as a brecciation at
the junction, an excellent example of which was photographed some
years ago. In other cases the junction of kaolin-vein and clay is very
confused, and pieces of the kaolin are separated from the parent vein.

Against the evidence of the kaolin-veins must be set the buried
trees that are occasionally found. I have explained these as being trees
that have fallen into old and forgotten excavations. The sandy
casing found round some of them supports this view (vide Q.J.G.S.,
Ixvili, pp. 150-1, fig. 5, 1912), but a section has lately been photo-
graphed, unfortunately too late for illustration ; that is a puzzle I am
unable to solve. It occurs on the Gopeng Consolidated property.
On the right is a very clearly-marked fault with grey pebble-beds
and clay on the right of the fault, and the same beds, stained
red and disturbed, on the left. ‘To the left of the fault is part of
a big kaolin-vein. It looks as though it had been slightly bent by
movement of the clay, but can only be regarded as intrusive, since it
is the same vein as that mentioned above as being bordered by mica-
tourmaline rock. There are masses of kaolin, isolated in section,
which may be joined to the parent vein further in, or may be portions
sheared off by settling over the limestone. The fault does not touch
the main mass of kaolin. Only six feet, or thereabouts, above the
kaolin is a mass of wood around which I could find no casing when
I saw it some days after it was first uncovered. Here, then, we have
a kaolin-vein that has effected alteration of the rock it is intruded
into, well-preserved wood 6 feet from it in the same clay, and a fault
that does not help matters one way or the other.

In an earlier chapter the possibility was touched on of there being
in the Kinta Valley detrital deposits belonging to the era when the
Peninsula was united to the Archipelago or to that when the former
was a group ofislands. This must be considered briefly in connection
with the Gopeng deposits.

168 T. H. Withers—Shell-fragments

One reason against regarding these bedded deposits as recent -
alluvium is their position. They form part of a watershed. They
rise to a considerable height above sea-level; they are as high as
much of the land formed of shale and quartzite’ in the centre of the
Kinta Valley ; and they differ from the recent alluvium in containing
much less vegetable matter, the few buried trees being the only
material of this nature. Their position, however, does not preclude
their being the remnant of deep alluvial deposits that filled a valley
when the Peninsula and the Archipelago were united, but the
difficulty is to reconcile with this possibility the evidence of the
kaolin-veins, which must in that case have been intruded into surface
deposits.

The same objection applies to their being formed in the sea when
the Peninsula was a group of islands, and there is the further objection
that the deposits at Gopeng do not resemble the familiar coast deposits
of to-day. If they are considered to be of marine origin we have to
face the absence of marine organization and mangrove mud.

Both in the case of unbedded and bedded deposits there is still the
question of the origin of the tin-ore to be noticed. Its most striking
feature is its angularity, which was shown in plate iv of the earlier
edition. On the west of the Kinta River there is no doubt that some
of the ore was brought by media that came through the limestone
from the granite of the Kledang Range or direct from granitic intru-
sions such asthat at Pusing Lama. But thisis not sufficient to account
for all the ore, and I think the only satisfactory solution is that
detrital ore derived from an older granite was added to by a younger
granite. It must be remembered that large areas of limestone bed-
rock have been exposed showing no veins by which tin might have
come to the rocks above.

At Tekka and Gopeng the angularity of the detrital ore is against
its being alluvial, and on the Kinta Tin Mines Ltd. property and
elsewhere evidence has been found of enrichment from the kaolin-veins
and the granite of the Main Range. The detrital ore must be older
than the kaolin-veins, and therefore, we must conclude, older than
the granite of the Main Range, and it should be kept in mind that
the granite fragments in the altered volcanic ash of Pulau Nanas,
near Singapore, show that a granite mass older than the granite of
the Main Range once existed (Q.J.G.8., Ixvi, p. 428, 1910).

On pp. 89 and 40 of the 1913 publication I gave some objections
to these Kinta tin-deposits being held to be of glacial origin. The
Siputeh section is certainly a further objection, but, seeing that
extensive glaciation is known to have existed on Gondwanaland about
the time when these beds were laid down, a glacial origin appears to
meet more of the facts than any other explanation.

IIiI.—Some Prrecypop SHELL-FRAGMENTS DESCRIBED AS CIRRIPEDES.
By THOMAS H. WITHERS, F.G.S.

MONG a number of Cirripede plates from the Chalk Marl and

Cambridge Greensand of Cambridge submitted to me some time

ago, were certain fossils which at first puzzled me considerably.

described as Orrrupede Valves. 169

Although there were more than twenty examples, all came apparently
from the same side of the animal, that is, they were not left and
right, and this led me to suspect that they were not Cirripede valves,
and to examine them more closely. One edge close to the narrow
end of the shell was then seen to be broken quite clean and straight,
and on comparing these fossils with some Pelecypod shells from the
same horizon it was quite clear that they were the anterior ears of
right valves of Aucellina grypheoides (Sow.) (Text-fig. 7, p.170), a shell
belonging to the family Pteriide (see H. Woods, Pal. Soc. Monogr.

(etaceane Mollusca, 1905, vol. ii, p. 72, pl. x, figs. 6-13). Other
specimens submitted at various times from Jurassic and Cretaceous
rocks, turned out on examination to be the anterior ears of the right
valves of Pelecypod shells like Pecten, anda number of such specimens
were included among some Cirripede plates from the Chalk of Rigen
obtained for the British Museum by Frau Agnes Laur.

Since the superficial resemblance to Cirripedes of the anterior ears
of the right valves of Pecten-like shells and other shell-fragments,
has resulted in their mistaken identification by collectors, even those
of experience, it is not surprising that some authors should have
described and figured such fossils as species of Cirripedia.

Thus, Darwin has figured as a carinal-latus of the Cirripede
Scalpellum solidulum, the anterior ear of a Pecten from the Cretaceous,
and a recent examination of the holotype of the supposed Liassic
Cirripede Pollicipes alatus, shows that this is another case of the
anterior ear of a Pelecypod being mistaken for a Cirripede valve.
One or two other instances have been noticed while going through
the Cirripede literature, and it was thought advisable to include them
in the present note, for this will serve not only to call attention to
these remains, but will be a further step towards ridding the
Cirripedia of all such non-Cirripede material.

Zoocarsa DoLIcHoRHAMPHIA H. G. Seeley. (Text-fig. 1, p. 170.)
1870. Zoocapsa dolichorhamphia, H. G. Seeley, Ann. Mag. Nat. Hist., ser. Iv,

vol. v, p. 283. :

1877. ns i n (=Avicula or Pecten): H.
Woodward, Brit. Mus. Cat.
Brit. Foss. Crustacea,
p. 146.

1891. a 4 at (=Avicula or Pecten): H.

Woods, Cat. Type Foss.
Woodwardian Mus. Cam-
bridge, p. 132.
Since this fossil from the Lias of Lyme Regis was described as
a sessile Cirripede by Professor Seeley, an examination of the type
was made by Dr. H. Woodward, who stated in his Catalogue (1877,
p. 146), ‘‘I am inclined to consider the ‘ tergum’ to be the wing of
an Avicula or Pecten, and the underlying ‘scutum’ to be another
portion of the same shell.” H. Woods (1891, p. 132) subsequently
recorded the fossil as ‘‘ Avicula or Pecten”’.
No figure has yet been given of this fossil, and only a very
inadequate idea of it can be deduced from the description. The
specimen really consists of seven or eight fragments of Pelecypod

170 T. H. Withers—Shell-fragmenis

shell embedded closely together, and only one fragment shows the
outer surface. From their colour and appearance they evidently
belong to more than one form of shell, but it is impossible to discover
much from the inner surface of mere shell-fragments.

The most conspicuous fragment is the irregularly triangular shell-
fragment marked II in Fig. 1, and this was Seeley’s ‘‘tergum”. It
is really the anterior ear of a right valve of a Pecten with a part of
the remaining shell, and shows the inner surface. The sub-
cylindrical shell-fragment regarded by Seeley as continuous with it
and as the ‘‘ beak” of the ‘‘tergum”’, does not appear to me to
belong to it. Above the ‘‘ tergum”’ isa four-sided shell-fragment (I)
called by Seeley the ‘‘scutum’’, but this is an indeterminable shell-
fragment quite unlike the inner surface of the scutum of a Cirripede.

4) ns.
Y)
yy

7:

1. Zoocapsa dolichorhamphia Seeley.

2. Pollicipes alatus Tate. (After Tate.)

3. Scalpellwm solidulum Steenstrup sp. (

ad He oe a (After Marsson.)
5 (
7

After Darwin.)

6 After Karakasch.)

Aucellina gryphcoides Sowerby sp. (After Woods.)
(Figures drawn by Miss G. M. Woodward.)

Projecting from under the ‘“‘tergum” is another fragment (III)
with slightly elevated wavy ribs, crossed at right angles by growth-
lines. ‘This is the only fragment showing the outer surface, and the
ornament of it agrees very closely with that of the Pelecypod Lima
gigantea, Sowerby. It represents Seeley’s ‘‘upper latus”. On the
opposite side of the ‘‘tergum’’, is another fragment (IV) regarded
by Seeley as one of the compartments, but though Molluscan it is
impossible to say to what shell it belongs. Professor Seeley stated,
“‘ Altogether the plates preserved would incline one to suspect that
there were no more.”’ Itis apparently to be understood from this

described as Cirripede Valves. Lid

that he did not include as belonging to his supposed Cirripede, the
three shell-fragments unnumbered in the figure.

Not only did Professor Seeley found a new genus for these shell-
fragments, which obviously belong to different Pelecypods, but he
regarded them as belonging to a Cirripede which was the type of
a new iamily intermediate between the Balanide and Verrucide,
with peculiar affinities towards the Lepadide. A Cirripede valve is
a well-formed structure, and in no way resembles the fragmentary
portions of shell in this fossil.

Ponticirrs anatus R.. Tate. (Text-fig. 2, p. 170.)

1864. Pollicipes liassicus, R. Htheridge, Quart. Journ. Geol. Soc., vol. xx,

p. 114 (nomen nudum).

TSTON e- ee ne Tate, Appendix I to Ann. Rep. Belfast Nat. F. C., p. 23,
Dla es 6:

This shell-fragment, which came from the Lower Lias ‘‘4. angu-
Jatus’’ zone of Island Magee, Antrim, was originally noticed by
R. Etheridge as a scutum of Podlicipes, and although he gave neither
description nor figure, he proposed for it the name Pollicipes liassicus.

R. Tate subsequently described and figured it as a scutum of
Pollicipes under the new name P. alatus. He remarked—‘‘ The
single scutal plate here figured is the one to which Mr. Etheridge
applied: the MS. name of P. lassicus; but, as another species was
described by Dunker with a similar denomination, P. diasinus,' it
appears to be advisable not to adopt Mr. Etheridge’s provisional
name. I, therefore, have selected that of P. alatus.”

The holotype of P. al/atus is now in the Geological Survey Museum,
Jermyn Street, registered 28849. Examination has shown that it is
not a Cirripede valve, but merely the anterior ear of a right valve of
a Pecten. Dr. F. L. Kitchin, who kindly examined the specimen to
see if the species could be determined, made the following
confirmatory report: ‘‘The type of Tate’s Pollicipes alatus is
undoubtedly the anterior ear of a right valve of a Pecten. I can
only say that it belongs to one of the smooth Pectens that have been
commonly ascribed to P. calvus, Goldfuss. Goldfuss only figured left
valves, and I am not absolutely sure that any of the specimens in
this museum ascribed to his species are truly identical with it. But
Tate and others have referred certain smooth forms from the
angulatus and overlying zones to this species, and in the absence of
an exhaustive enquiry based on much material it is usual to adopt
this provisional naming. It is not unlikely that more than one
species has been thus determined among our British material, but it
is to one of these that the supposed Pollicipes belongs. The specimen
is such a fragment that a precise determination of species is scarcely
to be hoped for.”’

In a paper ‘On a New Species of Pollicipes from the Inferior
Oolite of the Cotteswold Hills”, Gron. Mac., 1908, p. 341,

1 The name Pollicipes liasinus was given by Dunker (1848, Palgontographica,
Bd. i, p. 180, pl. xxv, fig. 14) to a supposed tergum from the Lias of Halberstadt,
and although the figure is not at all like that of a tergum of a Cirripede, an
examination of the specimen would be necessary before one could give an
Opinion as to its nature.

172 T.H. Withers—Shell-fragments described as Curripedes.

Mr. Linsdall Richardson states, ‘‘I have found several examples of
plates belonging to a species inseparable from this one [P. alatus,
Tate | in the Lias of oxynoti-armati hemere that was exposed when
excavations were being made for a new gas-holder at the Gloucester
Gas Works.” Mr. Richardson most kindly sent me examples of the
supposed Cirripede plates from that locality, and these confirm the
conclusion already arrived at that they, like P. alatus, merely
represent the right anterior ears of some form of Pecten-like shell.

ScALPELLUM soLIDULUM Steenstrup sp. (Text-figs. 3-6, p. 170.)

Steenstrup (1839, Kreyer’s Naturhist. Tidsskrift, Bd. 1, p. 412,
pl. v, figs. 14, 14*) founded this species on an. undoubted carina of
a Cirripede from the Chalk of Scania. Darwin, however, when
redescribing the species in his monograph (Pal. Soc. Monogr. Foss.
Lepadide, 1851, p. 42, pl. i, figs. 8a—f), included with a carina and
tergum, a Pelecypod fragment (figs. 8e-f) from Kopinge, Scania, but
this in no way affects the nomenclature of Scalpellum solidulum.
This shell-fragment (Text-fig. 3), which was considered by Darwin
to be a carinal-latus! of S. solidulum, really represents the anterior
ear of a right valve of a species of Pecten.

A shell-fragment (Text-fig. 4) of the same nature from the Chalk
of Riigen, was figured by Marsson (1880, Mitth. naturw. Vereine
Neu-Vorpommern und Riigen, Jahrg. xii, p. 15, pl. i, fig. 15), and the
figure given of that fossil is so good, and shows its fractured inner
edge so well, that one can only wonder that it should have been
described as a Cirripede valve.

Subsequently, N. I. Karakasch (‘‘Les Cirrhipédes du terrain
erétacé de la Crimée,” Trud. St. Petersb. Obsch. Estest., vol. xxx1,
livr. 5, p. 14, pl. i, figs. 17, 18), no doubt following Darwin and
Marsson, figured two similar shell-fragments (Text-figs. 5, 6) from
the Chalk (Upper Senonian) of Bakla, Crimea, as carinal lateral valves
of Scalpellum solidulum. These may not, however, belong to the
same species of Pecten to which the shell-fragments figured by
Darwin and Marsson belong.

Similar shell-fragments, which are undoubtedly the anterior- ears
of right valves of Pectens, were included with a large number of
Cirripede valves in a collection of fossils sent to the Geological
Department of the British Museum from the Chalk of Riigen, but, as
in the case of those figured by Darwin, Marsson, and Karakasch, it
would be a very difficult and unprofitable task to attempt to determine
the species.

ConcLusiIon.

While the present communication may be taken as showing that
certain so-called Cirripedes from the Jurassic and Cretaceous Rocks
are really the remains of Pelecypod shells, it must not be regarded as
exhaustive. It deals only with those of which the originals can be
examined, or as to the nature of which no doubt is possible. Some

‘In his other memoir (1851, Ray Soc. Monogr. Lepadide, p. 245) Darwin
thought that he was wrong in considering this to be a carinal-latus, and that it
was probably an upper latus.

Notices of Memoirs—Drawings in Spanish Caves. 173

other Jurassic fossils figured as Cirripedes are very doubtful, and an
examination of the originals will probably show that they do not
belong to the Cirripedia, but from the descriptions and figures it is
impossible to say what they really are.

NOTICES OF MEMOTRS.

a0 aa.
Drawines iv Spanisn Caves.

Los Grasapos dz ta Curva DE Prncues. By Epvarpo Hrrndnpez-
Pacurco. Comisidn de Investigaciones Paleontologicas y Pre-
historicas, Mem. No. 17, Madrid, 1917.

HE Spanish Government is to be congratulated on the valuable
memoirs on Geology, Prehistoric Archeology, Zoology, and

Botany which are being issued in rapid succession from the National

——

So

Drawing of a hunted deer, pierced with arrows, on the wall of the cavern of
La Pena, San Romdén de Candamo, Asturias, Spain. Original about
4 feet in depth.

Museum of Natural Sciences in Madrid. They are making known
the scientific treasures of Spain in a manner which has not hitherto
been possible; while their attractive style and their profusion of
admirable illustrations render them all the more welcome. The
memoirs on the prehistoric drawings in the Spanish caves are
especially interesting, and the latest, by Dr. Hernandez-Pacheco,
maintains the standard we have now been led to expect.

LA Reviews—The South Wales Coalfield.

The new memoir deals with incised drawings, chiefly of deer, in
a remote cave in the province of Burgos. Like many of the other
caves ornamented by Magdalenian man, it consists of little more
than irregular crevices in the Cretaceous limestone and could
scarcely have been used as a habitation. Dr. Pacheco thinks that
the drawings were made there by the hunters merely under the
impression that they would have some mystic influence on their
success in the chase. Some of the deer seem to be represented as
pierced by arrows, and Dr. Pacheco publishes for comparison with
them a most remarkable incised drawing of a hunted deer lately
found in the cave of La Pefa, in San Romén de Candamo, in
Asturias. This drawing is so extraordinary that: we venture to
reproduce it here. It shows the deer pierced by several arrows,
standing at bay, in evident distress, with protruded tongue. Of all
the drawings of game hitherto found in the Spanish and French
caves this is probably the most animated. The effect is even
enhanced by the skilful use of lines of shading, and we cannot but
admire the artistic powers of the old hunters who were able to
produce such work on irregular surfaces in dark recesses underground.

AL Sa We

RHVINWS-

Memorrs oF THE GroLocicaAL SURVEY.

I.—Tue Geotoey or tak Sourm Wates Coarririp. Part 1V: Tue
Country arounD Ponrypripp and Mazsrée. . By A. Srrawan,
F.R.S., R. H. lrppeman, and W. Grsson. Second edition, revised
by W. Grsson and T. G. Canrritz. Memoirs of the Geological
Survey, 1917. pp.ix +160. Price 38s. 6d.

f¥\HIS memoir deals chiefly with the occurrence of the coal-seams

in this area and their correlation, both at their outcrops and
in the shafts of the mines, the character of the coals being described
in a separate memoir dealing with the whole of the coalfield. The
coal occurs mainly in the Lower Coal Series, but also to some extent
in the Pennant Series; the Upper Coal Series is only present in one
or two places in the area. The higher coals are more bituminous
than the lower, and all the coals lose bituminous matter in a westerly
and north-westerly direction, as is common in South Wales. Since
the issue of the first edition numerous changes in the mines and
mining have taken place; for example, steam coals are now no longer
worked west of the Ogwr, while these coals are now being won from
deep shafts sunk through the Pennant Series north and north-west
of Llantrisant. Also the mining in the Ogwr and Avan valleys has
been considerably developed as a consequence of the building of
docks at Port Talbot, while the mining conditions of the Rhondda
valleys have altered but little. The memoir contains chapters
on the geological structure, the Mesozoic rocks, and the glacial
deposits. It is illustrated by figures and vertical sections showing
the correlation of the coal-seams, and is accompanied by a colour-
printed map (Sheet 248) on the scale of one mile to the inch, which
is a very good example of colour-printing. Wi. We

Reviews—Geology of North-Eastern Rajputana. 175

Indian Grotoey.

I1.—Tue Grotoey or Norta-Kastrrn Raspurana anp ADJACENT
Disrricrs. By A. M. Hrron, B.Sc., F.G.S., Assoc. Inst.C.E.,
Assistant Superintendent, Geological Survey of India. Memoirs
of the Geological Survey of India, vol. xlv, pt. i. Calcutta,
1917. Price 4s.

NHIS memoir deals with the re-survey of the above district, which
is roughly contained in a triangle, with the cities of Agra, Jaipur,
and Delhi at its apices; the original survey was carried out by C. T.
Hackett in 1881 and is now out ofdate. ‘The region is one of old folded
rocks; these had been denuded to a peneplain, uplifted a second
time, and now are in an advanced stage of the second cycle of
denudation. The greater part of the district is covered with |
alluvium, but in the south-west part the old rocks come to the
surface over a considerable area; the dips here are always high, and
the hard bands stand up as ridges with broad valleys between: this
close connexion between geological structure and topography is not.
common in this part of India.

Two distinct geological systems can be separated—an older, the
Aravalli system of Archsean age, which may be correlated with
the Dharwar system of Cental and Southern India, and a newer, the
Delhi system, which is placed among the Lower Purana rocks. The
interval separating the two systems corresponds to the Ep-archean
interval of North America.

The Aravalli rocks are exposed along the anticlines of the post-
Delhi folding and consist of highly metamorphosed sediments with
some intrusive granites, amphibolites, and quartz veins. The Delhi
system begins with an inconstant quartzite which is overlain by the
Rialo limestone. This limestone is a pure dolomite and usually
forms low-lying country, with the exception of a few residual knolls.
of ironstone formed by metasomatic alteration. The succeeding
Alwar series consists of quartzites, grits, and associated volcanic
rocks, invaded by granites, pegmatites, and basic sills, now altered
to amphibolites. ‘These rocks are succeeded by a banded siliceous
limestone, the Kushalgarh limestone, with which is associated a
peculiar rock known as the ‘‘hornstone breccia’. Finally, the
Delhi system is completed by the Ajabgarh series, which is composed
chiefly of clays with impure quartzites and limestones, and shows
deeper-water conditions than the Alwar series.

The hornstone breccia which is found sometimes below and some-
times above the Kushalgarh limestone is a very remarkable rock. It
consists of angular fragments of quartzites, identical with the
Alwar and Ajabgarh quartzites, some pieces of slate similar to the
Ajabgarh slates, and brecciated white vein quartz in a very finely
granular matrix, the grains of which are coated with limonite, and
which is occasionally sufficiently ferruginous to be used as an iron
ore. It is suggested that the rock was formed by the crumpling of
alternating beds of quartzite and slate under the stress of the post-
Delhi folding; the quartzites, being brittle, would break and be
pushed into the more yielding slates. Into this shattered rock,

176 Reviews—Iron-ores of Canada.

veins of quartz were intruded, and some iron and copper were intro-
duced into the matrix. Finally the whole mass was again brecciated
by further folding.

The post-Tertiary formations which cover the old rocks over a
great part of the area are partly the old alluvium of the Ganges and
partly blown sand; a considerable amount of Kankar is found near
the outcrop of lime-bearing rocks.

The district contains a fair number of minerals of economic
importance, but unfortunately only in small quantity.

The irregular patches of Rialo limestone altered to hematite,
which contain seams up to 7 feet in thickness, appear to be a
workable proposition. A fairly large amount of iron has been
smelted in this region in past times, but all the mines are now closed.
Copper was mined on a considerable scale in ancient times, but none
is now extracted.

The ore was chalcopyrite with pyrrhotite occurring along the
junction between quartzite and slate at a horizon low down in the
Alwars. Some kaolin is dug from the pegmatites, and steatite and
a variety of building stones and marbles are also quarried in the
district.

The memoir is illustrated by many excellent drawings and
photographs of the scenery and structures in the field, photographs
of specimens, and photo-micrographs of thin sections, and also by
a geological map and a number of horizontal sections.

Wi Hep

CANADIAN [RON-ORE.

TII.—Inon-ornr Occurrences in Canapa. Vol. I. By E. Linpeman
and L. L. Botron. Department of Mines, Canada. pp. 71, with
23 plates and 1 map. Ottawa, 1917.

{THE literature of the Canadian iron-ore deposits has till now been
very scattered and difficult of access, and the Department of
Mines has rendered a useful service by collecting all the available
data in this convenient form. Jron-mining was not seriously
developed in Canada till 1896, but since that date it has made rapid
progress. Nevertheless, even now the proportion of ore mined in the
Dominion is only about 15 per cent of that smelted in Canadian
furnaces. The greater part comes from Newfoundland and the
United States. Among the provinces Ontario is the largest producer:
the most important source is the Helen Mine in the Michipicoten
district. The ore is hematite, probably derived from siderite and
pyrite by oxidation. Prospecting of large areas of banded jaspers
and magnetite schists correlated with those of the Vermilion and
Mesabi ranges in Minnesota has led only to disappointing results.
The only promising occurrence of this kind is the Akitokan iron-
range in Western Ontario, a magnetite ore with rather high sulphur
content. In British Columbia there are some promising contact-
deposits of magnetite which lie near coal and limestone, suitable for
use as fuel and flux. The great furnaces of Nova Scotia chiefly use
Newfoundland ore, but they were once supplied by local deposits of
hematite, limonite, and ankerite in strata of Devonian age. These

Reviews—Great Australian Artesian Basin. 177

seem to be contact-deposits, and they are rather rich in sulphur and
phosphorus.

This report contains detailed descriptions of a great number of
small occurrences of iron ores of almost every possible kind in all
parts of the Dominion, but most of these do not seem likely to be of
much importance, at any rate in the immediate future.

An interesting and useful appendix contains a detailed description
of the Wabana mine in Newfoundland, now one of the largest iron-
mines in the world, which supplies much of the ore for the Canadian
furnaces. ‘here are five beds of ironstone, from 5 to 30 feet thick,
intercalated in Ordovician sandstones and shales. The ore is chiefly
hematite, with some siderite and chamosite. Theiron content is on
the average 53 per cent, with silica up to 10 per cent and about 0°85
per cent of phosphorus. The ore-reserves are very large; a con-
servative estimate is 2,000,000,000 tons, and this figure may
eventually be much exceeded. The mines are very conveniently
situated for shipment of the ore, being close to the coast, where the
water is sufficiently deep for large ships close in shore. The loading
_ facilities are so extensive as to permit the loading of 5,000 tons of
ore per hour. Part of the workings extend under the sea.

It is interesting to note that a large use has been made of
magnetic surveys in investigating the iron-ore deposits of Canada, as
this method was found to give useful results in Sweden.

Jie Mel ate

ArrEstaN WaTERS oF AUSTRALIA.

1VY.—Tur Prosiem or trae Great AusrraLian Arrestan Basin. By
A] i, pu Vor. Journ. Proc. Roy. Soc: N. 8. Wales, vol. li,
De Loo lO iT. @
N the light of his extensive experience of South African geology
Dr. du Toit has re-examined the whole problem of the origin of
the great artesian basin of Australia. Professor Gregory concluded,
in opposition to the views of many Australian authorities, that the
water was partly of magmatic origin and partly water included in
ancient sediments during their deposition, only a small part being of
modern meteoric origin; Mr. Symmonds considered that most of the
water was juvenile in the sense of Suess. Dr. du Toit’s views agree
in the main with those of Professor Gregory in that he regards the
waters as originating from three sources: (1) residual (Mesozoic),
(2) plutonic, (3) Tertiary. The bulk of the Mesozoic water is
believed to have been replaced by alkaline water derived from
igneous intrusions: these waters are rich in sodium carbonate. On
the eastern side of the basin early Pleistocene surface water drove out
much of the still earlier accumulation and carried salts downwards.
However, Dr. du Toit believes that at the present time the meteoric
source is of most importance in keeping up the supply, though much
of the older water may still remain. The notable and alarming
falling-off in the yield of the wells observed of late years suggests
the urgent need for efficient Government control of borings in the
artesian area. Re He Re
DECADE VI.—VOL. V.—NO. IV. 12

178 = = Reviews—Mining in South Australia.

V.—A Review oF Mrinine Operations IN THE STATE OF Sovute
AUSTRALIA DURING THE HALF-YEAR ENDED JuNE 80, 1917. No. 26.
Compiled by Lionen C. E. Grz, S.M. Adelaide, 1917. |

N addition to the mineral statistics for the half-year this review
contains an account of the Government diamond drilling opera-
tions, with logs of the bores, an account of several districts where
there are mineral deposits which seem worth further prospecting, and
an account of several mines which are either closed down or doing
little work, with suggestions for their improvement. Among the
deposits not yet fully prospected are deposits of apatite and graphite
and also a large pyritic quartz lode which is regarded as a possible
source of sulphur.

The apatite deposit is situated at Boolcoomatta Spring and consists
of pegmatites occurring in Pre-Cambrian gneisses and schists. The
pegmatites are very coarse-grained, containing felspar crystals up to
6 inches in length and plates of muscovite up to 1 inch in width.
There are considerable numbers of veins, of which a fair proportion
contain apatite in amounts varying from 5 to 60 per cent. The
graphite deposits are situated chiefly in the southern part of Hyre’s
peninsula and consist of graphite schists in a series of gneisses,
schists, and quartzites of Pre-Cambrian age. The outcrops are much
weathered and decomposed, so that a fair determination of the flake
graphite present cannot be made, but it is suggested that the quality
will improve in depth when the oxidized ferruginous zone is pene-
trated. This deposit is regarded as an important one owing to the
present large demand for flake graphite for the manufacture of
graphite crucibles. The review shows great enterprise on the part
of the Government geologists in seeking out new deposits and in
trying to revive those mines which for various reasons have ceased
work or are likely to be closed. WH We

VI.—A New Test or tHe Sussipence ‘'Heory oF Corat Reers.
By R. A. Daty. Proceedings of the National Academy of
Sciences, vol. 11, p. 664, 1916.

fZ\HE author points out that during the formation of atolls according

to Darwin’s theory a concavity or ‘‘moat’’ must have been
formed between the up-growing reef and the subsiding island. The
filling of this moat, which has never been properly discussed, affords
another test of the applicability of the theory. The moats have
always been completely obliterated and the lagoons are very shallow.
he possible source and means of transport of the material required
for this filling are discussed in detail by the author. The lagoon
floor is generally sandy and not covered by growing coral and other
organisms, while the transport of sand by waves and currents can
only be small and local. The levelness of the floor is inconsistent
with filling by this means. ‘The general conclusion is drawn that
the processes mentioned are not adequate to explain the facts; and
that existing coral-reefs are new upgrowths from platforms formed
previously to and independent of reef-growth. The final preparation
of the platform is supposed to have taken place during the Glacial
period. Ree SER Re

Reviews—New Fossil Corals, Pacific Coast. 179

VII.—New Foss Corts rrom tHE Paciric Coast. By Jorcrn O.
Nomuanp. University of California publications in Geology,
vol. x, No. 13, pp. 185-90, pl. v, 1917.

‘IVE new Tertiary Corals are described and figured, namely,
k Astrangia boreas, u.sp., Pleistocene (?), Douglas I., South-
Eastern Alaska; 4. grandis, n.sp., Pliocene, Middle Fernando series,
Guadalupe, Santa Barbara County, California; Astreopora occidentalis,
n.sp., Tertiary (?), near Newport, Oregon; Caryophyllia oregonensis,
n.sp., Oligocene, Astoria series, near Smith’s Point, North-Western
Oregon; Dendrophyllia californiana, nu.sp., Oligocene, Agasoma
gravidum beds, near Walnut Creek, Contra Costa County, California.
An undetermined species of Balanophyllia also is recorded from the
Pliocene, Middle Fernando series, Fugler Point, S.E. of Santa Maria,
Santa Barbara County, California, which is of interest as the ‘‘ genus |
has heretofore been unknown in the Tertiary deposits of the Pacific
Coast later than the Oligocene”’’.

Finally, an Oligocene Coral-fauna is mentioned, consisting of
Balanophyllia sp., Flabellum sp., Paracyathus sp., Pocillopora (?) sp.,
Sphenotrochus (?) sp., and two species of Zrochocyathus ‘‘ associated
with Dendrophyllia hannibali, Nomland, or in the same series of beds as
that species’’, in the Astoria group of South-Western Washington.

Wiebe la:

REPORTS AND PROCHHDINGS.

I.—GerotocicaL Socirry or Lonpon.

1. Annuat GrenerRaL Meerine.

February 15, 1918.—Dr. Alfred Harker, F.R.S., President, in the
Chair.

The Reports of the Council and the Library Committee were read.
It was stated that there had been a total accession of 29 Fellows in
the course of 1917. During the same period the losses by death
and resignation amounted to 43. The total number of Fellows on
December 3l, 1917, was 1,220.

The Balance-sheet for that year showed receipts to the angen of
£2,966 10s. 8d. (excluding the balance of £676 12s. 5d. brought
forward from 1916) and an expenditure of £3,581 1s. 6d. (including
the purchase for £475 of £500 5 per cent War Loan).

The Reports having been received, after a brief discussion, the
President handed the Wollaston Medal, awarded to Dr. Charles
Doolittle Walcott, F.M.G.S., to Mr. William H. Buckler, Attaché
to the Embassy of the United States of America in London, for
transmission to the recipient, addressing him as follows :—

Mr. BuckiEr,—The Wollaston Medal, the highest honour at the
disposal of this Society, is conferred upon Dr. Charles Doolittle Walcott
in recognition of his eminent services to Geology and Paleontology, more
particularly among the older fossiliferous rocks of North America.
While his administrative work, both on the United States Geological
Survey and at the Smithsonian Institution, has done much for science in

his own country, his personal researches have excited interest and admira-
tion wherever Geology is cultivated.

180 Reports & Proceedings—Geological Society of London.

He has made important contributions to the history of the Algonkian
formations, and his discoveries lead us to hope that the less altered of those
ancient sediments may ultimately yield more abundant and definite relics
of pre-Cambrian life. His detection of fish-remains in the Ordovician rocks
of Colorado, again, carried back by a stage the earliest appearance of
vertebrates in the succession of life-forms. But it is in the Cambrian
strata that Dr. Walcott has found chief scope for his labours, which,
pursued principally upon the American continent, have often had a world-
wide importance. Realizing the dual part which the exponent of
Paleontology is called upon to sustain, he has illuminated that science
alike in its geological and in its biological aspect. Under the former head
should be mentioned the determination and collation of the stratigraphical
sequence in numerous districts, and the light thrown thereby upon the
problems of Paleophysiography. In particular, Dr. Walcott’s study of
the geographical distribution of the Cambrian faunas, establishing the
existence of two distinct provinces, marked a signal advance in this field.
On the biological side his work has been no less fruitful in results. It is
sufficient to recall the series of memoirs dealing with the Trilobites, in
which he greatly elucidated the organization of that important group, and
again his two handsome volumes on the Cambrian Brachiopoda.

In recent years, with energy which a younger man might envy, he has
pushed his researches into the Rocky Mountains of Canada, amidst scenery
which his beautiful photographs have made known to many. There he has
been rewarded by the bringing to light of two richly fossiliferous horizons
in the Middle Cambrian succession, including in one an assemblage of
fossils marvellous for the perfect preservation of their detailed structure.
The preliminary account of the discovery has aroused keen interest, and
paleontologists eagerly await the full description by a master hand of this
unique collection.

If by his official status, joined with his personal record, Dr. Walcott is
in some sense representative of American geology, with its large oppor-
tunities so ardently embraced, the occasion may remind us that community
of scientific interests is perhaps not least among the links which unite your
country to ours. I have much pleasure, Sir, in placing this Medal in your
hands for transmission to its recipient, and trust that his future career may
include achievements no less brilliant than those which we commemorate
to-day.

Mr. Buckler replied in the following words:—

Mr. PrestpENt,—Mr. Page greatly regrets that a long-standing engage-
ment prevents him from receiving this Medal in person. He has asked me
to convey to you Dr. Walcott’s deep appreciation of the honour awarded
by your Society and to assure you that this feeling is shared by our fellow-
countrymen. Let me thank you, not only for this high distinction con-
ferred upon American Geology in the person of one of its leading
representatives, but also for the wishes which you have expressed, and in
which all Americans will heartily join, for Dr. Walcott’s future labours.

As a former President of the Baltimore Society of the Archeological
Institute of America, I may mention that Dr. Walcott presides over the
Washington Society of that Institute, a fact reminding us that his wide
interests include Archeology, the younger sister of Paleontology.

In these times and on such an occasion one cannot but recall-—-as you,
Sir, have said--the community in scientific, as in literary and political,
activity which exists between the English-speaking peoples on both sides
of the Atlantic. It is significant that of the two American Institutions in
which Dr. Walcott has served as Secretary, the Smithsonian was founded
by. an Englishman, the Carnegie bya Scotsman. The partnership in arms,
which now as never before unites our peoples, cannot fail in the coming
years to strengthen and to extend that scientific comradeship of which your
tribute to Dr. Walcott is a signal recognition.

Reports & Proceedings—Greological Society of London. 181

In handing the Murchison Medal, awarded to Joseph B. Tyrrell,
M.A., to the Hon. Sir George Halsey Perley, K.C.M.G., High
Commissioner for the Dominion of Canada, for transmission to the
recipient, the President addressed him as follows :—

Sir Grorcr PrriEY,--The Murchison Medal has been awarded to
Mr. Joseph B, Tyrrell in recognition of the value of his many services to
geological science. In the breadth of their scope, in the pioneer element
which has so largely entered, in the practical benefits which have often
followed, those services may stand as typical of Canada’s contribution to
Geology.

During more than thirty years Mr. Tyrrell has been frequently engaged
in exploring wide tracts of the little-known Barren Lands of Northern
Canada, making prolonged journeys of a kind which demands no ordinary
resolution and endurance. Besides thus adding largely to geographical
knowledge by his own efforts, he has done much to make known the results
of earlier explorers in the North. While helping very materially to
develop the mineral resources of the Dominion, he has at the same time
gathered much valuable information touching the older rocks of the region ;
and, uniting in his own person the geologist and the prospector, he has
often shown by example how science and enterprise may go hand in hand,
to the great advantage of both.

On the side of pure science, however, his most notable researches have
been in the domain of Glacial Geology, where his extensive acquaintance
with the country has enabled him to arrive at conclusions of a large order.
Prior to 1894 it was generally held that the ice which once overspread
Canada, east of the Cordillera with its mountain glaciers, emanated from
a single centre of dispersal.” Mr. Tyrrell first demonstrated the existence
and approximate limits of a great ice-sheet, which he named the Keewatin,
centreing in the country west of Hudson Bay and distinct in origin from
the Labradorean ice-sheet on the east. To these two he subsequently
added-a third, under the name of the Patrician Glacier, which had its
gathering-ground to the south of Hudson Bay. His development of this
thesis, involving a discussion of the relations in time and space of the ice-
sheets radiating from different centres, must rank among the most im-
portant contributions to the Glacial history of North America.

In forwarding to Mr. Tyrrell this token of recognition from the Council
of the Geological Society, I beg, Sir, that you will add to our congratula-
tions upon what he has already accomplished our hope that many years of
activity still remain to him; and this wish will, I am sure, be echoed by
his numerous friends on both sides of the Atlantic,

Sir George Perley replied in the following words :—

Mr. PresipeNtT,—I am very happy to come here to-day and receive this
Medal on behalf of Mr. Tyrrell, and I only regret that he is not here him-
self for that purpose. He was in London for some time last year, but
unfortunately had to return to Canada last month, so that he has missed
the pleasure of being with you to-day. As I live in Ottawa, I have known
Mr. Tyrrell for a long time. He is a native-born Canadian, and was for
many years connected with the Canadian Geological Survey. He showed
much resource and energy in his work, and it is very fitting that he should
be recognized by your Society in this way.

I may say that, in our Dominion, we are proud of our Geological Survey
and of what it hasdone. We have a large country with great undeveloped
mineral resources, which the Geological Survey has done a great deal to
help discover and utilize. Fortunately, Canada has been able to assist
more than could have been expected in providing minerals and metals
during the War. Many supplies from enemy countries have been cut off,
and higher prices have encouraged enterprise. In consequence, we have
not only provided large quantities of nickel, but we have developed our

182 Reports & Proceedings—Ceological Society of London.

copper, lead, and zinc industries to a very considerable extent. Even so,
I feel sure that our mineral and metal products will be greatly increased in
the future, and we believe that our resources in that direction have been
hardly scratched. To exemplify this, I would remind you that the
wonderful silver deposits at Cobalt, in Ontario, we only discovered by
chance, although lumbering had been carried on over that district for a
great many years. The Ontario Government built a line of railway from
the Canadian Pacific into the North country, and in so doing crossed this
great silver deposit, which is still producing heavily.

As representing Canada, I am proud to receive this Medal on account of
our Dominion, as well as on account of Mr. Tyrrell personally. It seems
peculiarly appropriate at this time that this honour should be given by
this old and important Society to a Canadian, and we appreciate the same
greatly.

I accept the Medal on behalf of Mr. Tyrrell with grateful thanks, and it
will give me much pleasure to forward it to him and communicate the
very kind words with which you, Mr. President, have accompanied it.

The President then handed the Prestwich Medal, awarded to
Professor William Boyd Dawkins, F.R.S., to Dr. A. Smith Wood-

ward, for transmission to the recipient, addressing him as follows :—

Dr. SmitH Woopwarp,—The Prestwich Medal has this year heen
awarded to Professor W. Boyd Dawkins, and there will appear, I think, a
peculiar fitness in the choice which links together these two names.
Much of the geological work which here receives recognition is such as
would especially appeal to the Founder of this Medal, and did in his life-
time engage his lively interest.

During fifty-six years Prof. Dawkins has contributed nearly thirty papers
to the Quarterly Journal of this Society, in addition to numerous works
published elsewhere. His researches in British cave-deposits and in
mammalian paleontology have long been well known and highly valued.
He has shown that mammalian remains can be used in the classification of
the Tertiary strata, and in many ways has cast light upon some interesting
chapters in the later geological history of Europe. In another direction he
has made important additions to our knowledge of the geology of the Isle
of Man. His long connexion with the Victoria University and the support
which he has given to the Manchester Geological Society have done much
to promote the study of geology in Lancashire, and his well-known
publications Cave Hunting and Harly Man in Britain met the needs of a
wide circle of readers.

Even more, perhaps, will the name of Prof. Dawkins be always associated
with the discovery of the Kentish Coalfield, in which he guided to a
successful issue an enterprise that had already exercised the mind of
Prestwich himself. The site of the boring at Dover was selected after a
careful survey of the district, and much patient labour was expended on
the examination of the cores and the identification by their fossils of the
several geological horizons pierced. Apart from the material success
realized, there was in this way accumulated a body of information which
has important applications to the stratigraphy and tectonics of South-
Eastern England.

On behalf of the Council, I ask you to transmit this Medal to Prof. Boyd
Dawkins in token that he has indeed, in the words of the Founder, ‘‘ done
well for the advancement of the science of Geology.”

Dr. Smith Woodward replied in the following words :—

Mr. PresipENT,—I have much pleasure in receiving this Medal on
behalf of Prof. Boyd Dawkins, on whom it has been so worthily bestowed.
He desires me to express his regret that an unavoidable engagement in
Manchester prevents him from being present to-day to return his thanks
in person.

Reports & Proceedings—Geological Society of London. 183

He writes :—

*“T feel deeply the honour that the Council have conferred upon me. It
is specially valuable to me from my long friendship with Prestwich, and
because my scientific life has been mainly spent in following up the lines of
inquiry which he made his own—the range of the Coal-measures under the
Secondary and Tertiary strata of South-Eastern England, the classification
of the European Tertiaries, and the problem of the antiquity of man in
Britain. With regard to the first, it may be noted that the South-Eastern
Coalfield is now clearly defined, and now ranks among the assets of the
nation. With regard to the second, the classification by the evolution of
the higher mammalia originally intended for Europe is found to apply to
the whole of the world. It is now being used by the American geologists
(Prof. Osborn and others) to define the complicated subdivisions of the
Tertiaries of the New World. With regard to the third, the problem
remains now very much as it was in the days of Prestwich, and the zeal
of the antiquarians and anthropologists to discover the presence of man in
deposits older than the Pleistocene Period has been met by the caution of
the geologists, with the net result that the Piltdown remains stand as the
oldest in the geological record of Great Britain, and that the alleged
occurrence of traces of man in the Pliocene and older strata is put to
a suspense account.

‘**T value, however, the Medal more particularly, as a mark of regard on
the part of the Society, to which I have been able to contribute but little
for many years, owing to my duties in other directions.”

In presenting the Lyell Medal to Henry Woods, M.A., F.R.S.,
the President addressed him as follows:—

Mr. Woops,—The Council of the Geological Society has selected you for
distinction as one who ‘‘has deserved well of the Science”, and I think
that none who has watched your career and is acquainted with your work
will dissent from that verdict. Your communication to the Society, in
1896, on the Mollusca of the Chalk Rock, set a standard of skilful and
accurate diagnosis and description, which has been maintained in all your
subsequent work, including the important monograph on the Cretaceous
Lamellibranchia, published by the Paleontoyraphical Society. That the
philosophical side of Paleontology has also engaged your study is
sufficiently proved by such papers as that on the evolution of the genus
Inoceramus ; while that dealing with the igneous rocks of Builth shows
that your interests are not wholly comprised within one branch of our
science. Your text-book of Paleontology, based upon practical experience
at Cambridge, is valued by other teachers, and your knowledge has always
been, as I am well able to testify, generously placed at the disposal of
fellow-workers.

It will be, I trust, an encouragement to you, as it is certainly a source of
gratification to your friends, that so long a record of good work, faithfully
pursued for no private end, does not go unrecognized; and, as an old
colleague, I am pleased that it falls to my lot to place the Lyell Medal in
your hands as a tangible mark of appreciation.

Mr. Woods replied in the following words :—

Mr. PrestpENT,—Twenty years ago the Council gave me great encourage-
ment by awarding to me the Lyell Fund. The present award also comes
at a time when encouragement is welcome; not that I feel any loss of
interest in my work—far from it. But in these times one cannot help
regretting, amongst other things, that one’s special work in the past has
little, if any, bearing on matters which are now of practical importance. It
is, therefore, encouraging to find that the Council have taken a longer
view, and have continued their traditional policy of giving recognition to
any and every branch of Geology, whether it has any obvious practical use
or not.

184 Reports & Proceedings—Geological Society of London.

One of the things that struck me most at the beginning of my palonto-
logical work was the generosity and good-nature of those with whom that
work brought me into contact, and that pleasant experience has continued
all through ; whether I have had to do with officials in charge of museums,
with professional or amateur geologists, or with that useful person some-
times spoken of disparagingly as the mere collector, all have most freely
given me the benefit of their experience and the use of their collections ;
much as I should like on such an occasion as this to mention their names I
must refrain from doing so—the list is far too long, and I regret that it
now includes the names of not a few who are no longer living.

Whilst it gives me great pleasure to receive this mark of the Council’s
approval of my work, it gives me a further pleasure to regard it as a dis-
tinction for the Cambridge School of Geology. To those with whom
I have been associated in that school I owe much—to some of them I am
deeply indebted.

I thank the Council most sincerely for this Medal, and you, Sir, for
your kind words.

The President then handed the Balance of the Proceeds of the
Wollaston Donation Fund, awarded to Albert Ernest Kitson, to
Dr. H. Lapworth, Sec.G.S8., for transmission to the recipient,
addressing him as follows :—

Dr. LapwortH,—The Balance of the Proceeds of the Wollaston Donation
Fund has been awarded to Mr. Albert Ernest Kitson, in recognition of his
valuable contributions to Geology in Australia and West Africa.

Beginning in a clerical capacity on the staff of the Department of Mines
of Victoria, he qualified himself for scientific investigation, and became
ultimately Senior Field Geologist on the Survey of that State. Besides
taking an active part in the geological mapping, he wrote numerous papers
on the geology of Victoria, and seized opportunities to extend his researches
to New South Wales, Tasmania, and New Zealand. In 1906, on the
recommendation of his former chief, Prof. J. W. Gregory, Mr. Kitson was
placed in charge of the Mineral Survey of Southern Nigeria. With
characteristic energy, in a tropical climate, he traversed the Protectorate
in every direction, and, in addition to other services, was chiefly responsible
for the discovery and investigation of the Udi-Okana Coalfield, containing
vast supplies of coal, the more valuable for its geographical situation.
This Survey was suspended in 1911, and in 1913 Mr. Kitson received the
appointment, which he now holds, of Director of the Geological Survey of
the Gold Coast. His reports on that country have not yet been published ;
but it is perhaps permissible to mention the discovery of fossiliferous
Paleozoic rocks of considerable geological interest, and of deposits of
manganese-ore and of bauxite which have great economic importance.

That so notable a record of good work should receive recognition from
this Society must gratify all who are interested either in the advancement
of geological knowledge or in the mineral resources of the British Empire.

In presenting the Balance of the Proceeds of the Murchison
Geological Fund to Thomas Crook, Assoc.R.Coll.Sci., the President
addressed him as follows :—

Mr. Croox,—In awarding to you the Balance of the Proceeds of the
Murchison Geological Fund the Council wishes to recognize the value of
your contributions to Petrology and Mineralogy, more particularly with
reference to the mechanical analysis of rocks and also to the mineralogy of
the British Colonies. The former of these subjects engaged your attention
while you were at the Royal College of Science in Dublin, and you have
since pursued it with success, especially in perfecting the use of the
electro-magnet for the separation of minerals. As a member of the staff of
the Imperial Institute you have during recent years made many additions

Reports & Proceedings—Geological Society of London. 185

to our knowledge of the minerals of the more remote parts of the British
Empire, the results of your work appearing partly in papers published in
your own name, but largely in the pages of the Bulletin of the Institute.
Your petrological publications include some interesting observations on
** Dedolomitization ” and a suggestive paper on ‘‘ The Genetic Classification
of Rocks and Ore-Deposits”. In addition, you have collaborated with
Prof. Cole in an important memoir on a collection of rock-specimens
dredged off the coast of Ireland, showing how these may be made to yield
information concerning the submarine geology of the British seas. This
award, so well deserved, will, I hope, be an encouragement to you in your
future work, whether official or extra-official.

The President then presented a moiety of the Balance of the
Proceeds of the Lyell Geological Fund to Vincent Charles Llling,
M.A., addressing him as follows :—

Mr. Inninc,—The Council has awarded to you one moiety of the Balance
of the Proceeds of the Lyell Geological Fund to mark its appreciation of
your admirable work among the Lower Paleozoic rocks of Warwickshire.
Since its discovery by Prof. Charles Lapworth in 1882, the Cambrian inlier
of Nuneaton has claimed the attention of numerous geologists ; but it was
reserved for you to show how complete a development of the whole
Cambrian succession is there exhibited. Ina paper communicated to this
Society in 1914 you mapped out the various subdivisions which you had
recognized, and correlated them with the parallel sequence in other areas.
Of the Abbey Shales, representing in small compass a large portion of the
Middle Cambrian, you made a full palzontological study, describing
critically the rich trilobitic fauna and making known a number of new
species. That this important memoir was professedly only a first instal-
ment, warrants us in hoping that you will find in the present award
stimulus to the completion of your projected work.

In presenting the other moiety of the Balance of the Proceeds of
the Lyell Geological Fund to William Kingdon Spencer, M.A., the
President addressed him in the following words :—

Mr. Spencer,—A moiety of the Balance of the Proceeds of the Lyell
Geological Fund has been awarded to you by the Council as an acknow-
ledgment of the value of your paleontological work. :

Starting with the advantage of a zoological training at Oxford, you have
devoted the intervals of a busy official life to researches in the paleontology
of the Echinoderms. You began by applying Prof. Sollas’s method of
serial sections to elucidate the structure of the Paleozoic forms
Paleodiscus and Agelacrinus. You then devoted some years to the study
of the Cretaceous star-fishes, the results of which appeared in a monograph
upon the British examples and a paper, contributed to the Royal Society,
upon ‘‘The Evolution of the Cretaceous Asteroidea”. Therein you
showed, among other conclusions, that the star-fishes are of zonal impor-
tance, and that different lineages were evolved along parallel lines. More
recently you have been investigating with great skill that difficult group of
fossils, the Paleozoic Asterozoa, and your monograph, not yet completed,
has already brought to light many new facts relative to the morphology
and phylogeny of those early Echinoderms. It is our hope that this
recognition may encourage you to persevere in the same path.

The President then delivered his Anniversary Address, giving
first obituary notices of If, Emile Sauvage (elected Foreign Corre-
spondent 1879), W. Bullock Clark (For. Corr. 1904), T. McKenny
Hughes (el. 1862), Edward Hull (1855), R. H. Tiddeman (1869),
G. A. Lebour (1870), Arnold Hague (1880), Robert Bell (1865),
G. F. Franks (1890), G. C. Crick (1881), H. P. Woodward (1883),

186 Reports & Proceedings—Geological Society of London. —

Upfield Green (1889), C. O. Trechmann (1882), A. N. Leeds (1898),
R. Boyle (1911), A. M. Finlayson (1909), and others.

The President went on to discuss the present position and outlook
of the study of metamorphism. The rapid development of physical
chemistry and the successful application of experimental methods
to petrological questions have greatly changed the situation during
recent years, and for the first time it seems possible to approach the
subject of metamorphism systematically from the genetic standpoint.
For the geologist this implies the critical study, not only of the
great tracts of crystalline schists and gneisses, but equally of meta-
morphic aureoles, of pneumatolysis and other contact-effects, and of
the phenomena, mechanical and mineralogical, related to faults and
overthrusts. It implies, moreover, the recognition that these are
all parts of one general problem, that of the reconstruction of rocks
under varying conditions of temperature and stress. In practice,
this problem is complicated by the fact that perfect adjustment of
chemical equilibrium cannot be assumed, either in the rocks prior to
metamorphism, or during the process of metamorphism itself.

Some consideration was devoted to the solvents which play an
essential part in metamorphism and to the limits of migration of
dissolved material within a rock-mass. The Address proceeded to
the discussion of what is the most fundamental characteristic of
metamorphism: namely, that recrystallization takes place in a solid
environment, and so may be profoundly affected by the existence of
shearing stress. Stress of this type, on the one hand, arises from
the crystal growth itself, and on the other hand is called into play
by external forces. The automatic adjustment of the internally
created stress to neutralize that provoked from without affords the
key to all structures of the nature of foliation. The mineralogical
peculiarities characteristic of the crystalline schists must find their
explanation in kindred considerations; for it can be shown that the
chemistry of bodies under shearing stress differs in important respects
from the chemistry of unstressed bodies. ‘The result is seen in
the appearance of a certain class of ‘‘ stress-minerals’’ where the
dynamic element has figured largely in metamorphism, while in the
same circumstances the formation of minerals of another class seems
to have been inhibited. But, while some of the general principles
governing the effects can be formulated, the explanation of these
lines of the observed associations of minerals is a task for the future.
It may be that many of the particular problems involved will in
time be brought within the scope of laboratory experiment.

The conditions governing metamorphism are temperature and
shearing stress, with uniform pressure as a factor of less general
importance. If the orogenic forces are sufficient to maintain shearing
stress everywhere at its maximum, the stress itself becomes a
function of temperature, since this determines the elastic limit, and
the principal conditions of metamorphism come to depend upon a
single variable. This degree of simplification, however, is not to be
expected universally. One disturbing factor is the local rise of tem-
perature sometimes caused by the mechanical generation of heat in
the crushing of rock-masses.

Reports & Proceedings—Geological Society of London. 187

In resigning the chair, the President expressed his thanks to the
Fellows of the Society, and especially to the Officers, who, as well
as the permanent officials, had contributed much to the smooth
working of the Society’s business.

The ballot for the Officers and Council was taken, and the following were
declared duly elected for the ensuing year :—

OFFICERS (who are also ex-officio members of the Council): President -
George William Lamplugh, F.R.S. Vice-Presidents: KR. Mountford
Deeley, M.Inst.C.H.; Alfred Harker, M.A., LL.D., F.R.S.; Professor
William Johnson Sollas, M.A., LL.D., Se.D., F.R.S.; and Sir Jethro
J. H. Veall, M.A., LL.D., D.Sce., F.R.S. Secretaries: Herbert Henry
Thomas, M.A., Se.D.; and Herbert Lapworth, D.Sec., M.Inst.C.H.
Foreign Secretary: Sir Archibald Geikie, O.M., K.C.B., D.C.L., LL.D.,
Se.D., F.R.S. Treasurer; James Vincent Hlsden, D.Se.

Counciiu: Charles William Andrews, D.Se., F.R.S.; Francis Arthur
Bather, M.A., D.Se., F.R.S.; Professor John Cadman, C.M.G., D.Se.,
M.Inst.C.E. ; Arthur Morley Davies, D.Sc., A.R.C.Se.; Professor Edmund
Johnston Garwood, M.A., Se.D., F.R.S.; John Frederick Norman Green,
B.A.; Finlay Lorimer Kitchen, M.A., Ph.D. ; Major Henry George Lyons,
D.Se., F.R.S.; Professor John Edward Marr, M.A., Sce.D., F.B.S. ;
Richard Dixon Oldham, F.R.S.; Robert Heron Rastall, M.A. ; Professor
Henry Hurd Swinnerton, D.Se. ; Samuel Hazzledine Warren; Professor
William Whitehead Watts, M.A., Se.D., LL.D., F.R.S.

2. March 6, 1918.—Mr. G. W. Lamplugh, F.R.S., President, in the
Chair.

Mr. J. F. N. Green delivered a lecture on the Igneous Rocks of the
Lake District. He first drew attention to some of the manuscript
6 in. maps of the Lake District, prepared nearly fifty years ago, by
the Geological Survey, and pointed out that, although undoubtedly
most accurate, they differed greatly in the volcanic area from his
own. He suggested that the reason was that there was a funda-
mental difference in the classification of tuffs and lavas. A large
proportion of the Lake District rocks were brecciated, and had been
supposed to be altered tuffs. With the unbrecciated rocks into
which they passed they had been mapped as ashes. A number of
specimens and photographs were shown, indicating that the breccia-
tion and apparent bedding were due to flow. Specimens were also
shown of explosion breccias, of the normal tuffs (which the Lecturer
believed to be mainly the result of erosion between eruptions), and
of rocks simulating true tuffs, but actually sandstones and con-
glomerates, composed of detrital igneous material. Attention was
drawn to.the criteria for distinguishing the various types. Recently
manuscripts had been found in the possession of the Geological
Survey proving that Aveline, whose maps were extraordinarily
accurate and detailed, had anticipated by thirty years the Lecturer’s
separation from the volcanic rocks of the basal beds of the Coniston
Limestone Series.

When re-mapped on this basis, the Borrowdale Series appeared as
asimple and regular sequence, strongly folded and cropping out in
long bands. An interesting history of vulcanicity was revealed,
beginning in many places with explosion tuffs followed by a great
series of pyroxene-andesites over the whole district. Then there

188 Reports & Proceedings—Edinburgh Geological Society.

was a pause during which fine-grained andesite tuffs, with a tendency
to produce true slates, accumulated. This was succeeded by a vast
outpouring of andesites, of great thickness in the central mountain
region, but dying out southwards and eastwards. Next a series of
peculiar mixed tuffs, of special value in mapping, was covered by
another mass of andesites dying out south-westwards. After this,
soda-rhyolites covered the whole district, nothing later being
preserved—with one possible known exception. These volcanic
rocks were intersected by a varied series of intrusions.

The solfataric phenomena were of interest, including the pro-
duction of garnet and graphite, and a remarkable ‘‘streaky’”’
structure in the rhyolites.

An important question related to the age of the large acid
intrusions associated with the volcanic ee Were they of the
same age as, or later than, the Devonian folding? A sketch was given
of the evidence on which the Lecturer assigned the Eskdale and
Skiddaw granites to the Ordovician volcanic episode, and it was
suggested that the great Skiddaw anticline was not due to regional
folding, but a local structure connected with the vulcanicity.

Lantern-slides of Lake District country were shown, and the
manner in which the volcanic rocks entered into the scenery was
pointed out.

IJ.—Epinsuren GronocicaL Socrery.

February 20, 1918.—Professor Jehu, President, in the Chair.
(Issued March 16, 1918.)

1. ‘Coal Apples.” By J. Masterton, H.M.I.M.

At the Lochend Pit of Longrigg Colliery, Longriggend, in the
Upper Drumgray Seam, which is there anthracitic, Mr. Masterton
found in 1910 rounded balls of coal from 1% inches to 5 inches
diameter, and occasionally up to 8 inches diameter. ‘The balls were
slickensided, and, when seen in situ, the surrounding coal matter
was sometimes slightly displaced. The larger balls, when broken,
had a strong likeness to cone-in-cone coal. The late Dr. Clough was
shown the balls, and he drew attention to a note in the Transactions
of the Glasgow Geological Society recording the discovery of similar
balls in North Ayrshire by Mr. John Smith. Mr. Smith found. the
balls near a whin float.

The apples in Lochend Pit occur in an anthracitic coal, and
Mr. Masterton found similar balls in most of the pits near Lochend,
both in the Upper and Lower Drumgray Seams. The whin float
which underlies the Slamannan District has been proved by bores,
and is seen at the surface near Forrestfield, to the south of the
Lochend Pit; it has almost certainly both anthracitized the coal and
formed the apples, and Mr. Masterton cannot accept Mr. Carruthers’
assertions in the Geological Survey’s publications as to the formation
of the anthracites in the area in question by agencies similar to those
to which the anthracitization of the coals of South Wales has been
ascribed.

Obituary—Captain Lewis Moysey. 189

Specimens were exhibited from Lochend Pit (Upper Drumgray
Seam), Drumbon Pit (Upper and Lower Drumgray Seams), and from
Eastfield Pit (Upper and Lower Drumgray Seams).

Coal apples were found by Mr. Masterton during the years 1911
to 1918, and he exhibited specimens from the following localities :
(1) Moncur Colliery, Kilwinning—in the Ell Seam in a reversed fault,
and where a line of face was slightly baked and approaching a whin
dyke; (2) Littlemill Colliery, Rankinston—Main Seam, where the
working face was approaching a whin dyke; (8) Harallan Colliery,
Old Cumnock—Maid Splint Seam, ina place going parallel to a whin
dyke, and 25 yards distant from it; (4) Ponfeigh Colliery, Douglas,
Lanarkshire—apples described by the manager as occurring near
a whin dyke, the coal becoming coke close to the dyke.

Mr. Masterton advanced the opinion that the coal apples were
pieces of coal matter either of harder nature or of less volatile content
than the surrounding parts of the seam, and that these parts resisted
the compression and ‘‘ flux’’, if the term can be used, better than the
rest of the seam.

2. ‘*The Raw Materials of the Glass Industry.” (With lantern
illustrations.) By G. V. Wilson, B.Sc., F.G.S.

A brief description was given of the materials needed for the
manufacture of glass, with special reference to the quality of sand
used. The essentials of an ideal sand were pointed out, namely,
high percentage of silica, freedom from ferruginous materials, and
absence of refractory minerals, such as rutile and zircon. Attention
was drawn also to the importance of the size and shape of the grains.
Analyses of Fontainebleau and Dutch sands were compared with
those from the best Scottish localities. None of the latter are quite
equal to Fontainebleau, but several are as good as, if not better than,
Dutch. The essential qualities of the clay for making glass pots
were also noted, such as high plasticity, high refractory quality, and
freedom from iron in any form. The paper was illustrated by
lantern slides, many of which were photomicrographs showing the
minerals formed by the devitrification of a large body of glass.

OS eae Asm

CAPTAIN LEWIS MOYSEY,
hae VE Ce DAs. Mabe HG:

Born 1869. DIED FEBRUARY 26, 1918.

We much regret to learn of the death of Dr. Moysey, who was
lost on the hospital ship Glenart Castle, which was torpedoed on
February 26. Dr. Moysey had only just joined this ship, as one of
the medical officers, and he was not among those subsequently
rescued.

Dr. Moysey was a graduate of Caius College, Cambridge, and a
medical man who had long been in practice at Nottingham. He
was mobilized in the early days of the War, and until quite recently
he had been occupied with regimental work in this country.

190 Obitwary—Captain Lewis Moysey.

He had devoted, over a period of many years, the scanty leisure of
a busy professional life to the collection of the fossil remains of the
Coal-measures around his home at Nottingham. He was an
exceptionally ardent paleontologist, with a keen eye for a good
specimen, aud he was possessed of great skill and perseverance as
a collector.

He rediscovered a half-forgotten method of developing fossils
contained in clay-ironstone nodules, by freezing them in cold
storage. This he described in a paper in the Gronocican Maeazine
for 1908.

He also contributed several memoirs on some of the rarer specimens
in his collection. Among these may be mentioned his writings on
Paleoxyris and allied genera, published by the Geological Society in
1910 and the British Association in 1913 (1914), which did much to
clear up the obscurities which then surrounded these fossils. But,
as a rule, he was content, with great generosity, to place the
results of his labours in the field in the hands of specialists for |
description.

His collection covered a wide range both of Coal-measure animals
and plants, not a few being unique or exceptionally perfect examples.
Some of the former have been described in the pages of the
Grorocicat Macaziye, by Dr. Henry Woodward in 1907 and 1908
and) Dir Weak: Calman in 1914, and in the publications of the
Paleontographical Society by Mr. ’R. I. Pocock in 1911.

Dr. Arber some years ago (1910) also figured some of the best of
the plant remains in his collection, but many further examples
which Dr. Moysey had since acquired remain undescribed. It is not
too much to say that our exceptionally good knowledge of the fauna
and flora of the Notts and Derby Coalfield is due almost entirely to
his single-handed efforts, as his list of records contained in the recent
Survey memoir dealing with this field testifies.

A few weeks before his death, as if conscious of his impending
fate, Dr. Moysey made over as gifts his entire collections, the animal
remains to the Museum of Practical Geology in London and the
plant specimens to the University of Cambridge. The latter are
now in the Sedgwick Museum.

Dr. Moysey possessed many friends among those interested in Coal-
measure fossils, and his delightful personality, generous nature, and
enthusiasm for research had ‘endeared him to all of them.

[Nore sy roe Eprror.—Of the Arthropods discovered by Dr. L.
Moysey the first specimens were sent in May, 1907, to his friend
Mr. Henry A. Allen, F.G.8., of the Geological Survey, Jermyn
Street, and described by Dr. Henry Woodward in the Grorocrcar
Macazine for June, 1907 (pp. 277-82, Plate XIII). They consisted
of examples of Lurypterus (#. Moyseyi and EL. Derbiensis) from the
clay-ironstone nodules of the Coal-measures, Ilkeston, Derbyshire.

As the result of his experiments in splitting by a freezing and
thawing process the ironstone nodules obtained on the Shipley Hall
Estate clay-pit, near Ilkeston, Dr. Moysey records the fortunate
discovery of a greater proportion of rare fossils in these harder

Obituary—Captain Lewis Moysey. 191

nodules than from those found naturally inclined to split in the
clay-pit. Out of some ninety nodules cracked by freezing he had
obtained three specimens of Belinurus, one of Palgoxyris, two of
a ‘‘*new shrimp-like animal”, and one complete but diminutive
example possibly akin to <Arthropleura armata of Jordan from
Saarbrucken—he enumerated fifty-seven different fossil organisms
obtained (see Grou. Mae., 1908, pp. 220-2).

The new shrimp-like animal (Preanaspides precursor, H. Woodw.)
referred to by Dr. Moysey, and discovered by him, proved to be of
the very highest interest, being a Coal-measure representative, or
ancestral form, of the rare modern Schizopod Anasprdes tasmanie
from Mt. Wellington, Tasmania (see H. Woodward, Grou. Maa., 1908,
pp. 885-96).

On March 28, 1910, Dr. Moysey read a paper before the Geological
Society of London on Pal@oxyris and other allied fossils from the
Derby and Nottingham Coal-field (see Quart. Journ. Geol. Soc.,
vol. lxvi, pp. 329-44, pls. xxiv—vii, 1910).

- Dr. Moysey contributed a note on some undescribed Coal-measure
fossils from the Nottinghamshire coal-field (British Association,
Sheffield, 1910, Sect. C, see also Geox. Mac., 1910, p. 474).

In 1911 Mr. R. I. Pocock, F.R.S., contributed a ‘‘ Monograph of the
Terrestrial Carboniferous Arachnida of Great Britain” to the annual
volume of the Paleontographical Society for 1910,in which two
species obtained by Dr. L. Moysey are figured and described, namely:
Eobuthus holti, sp. nov. (see p. 15, pl. 1, fig. 2a) and Geralinura
britanniea, sp. nov. (p. 30, pl. ii, fig. 3).

In the Gronoetcat Magazine for 1911, pp. 497-507, twelve Text-
figures, Dr. Moysey described a further series of fossils from the
Notts and Derbyshire Coal-field, including a new _ bivalved
Entomostracan, Leava trigonioides, sp. nov. (Fig. 1, p. 498), parts of an
undescribed Arthropod, and remains of Prestwichia(?), of a Scorpion,
of Hurypterus, carapace of Anthracosiro sp., of A. Hritschiz, Pocock
(Figs. 7, 8, p. 508, and Fig. 9, p. 504), of A. Woodwardi, Pocock
(Fig. 10, p. 504), an opisthoma of Anthracomartus (Figs. 11, 12,
p. 505); he appends a list of sixteen Arthropods and six other
fossil remains.

At the Meeting of the British Association, Birmingham, 1913,
Dr. Moysey read a paper on Pal@oxyris and other allied fossils and
on Vetacapsula (see Grou. Mae., 1913, pp. 458-5). The author
compares these problematical bodies from the Coal-measures with
the egg-cases of Chimera collei, Rhinochimera, and other Chimeroid
sharks.

In 1914 (Guor. Mae., pp. 541-4, Pl. XXXVIII) Dr. W. T.
Calman figures and briefly describes a remarkable new form of
‘* Myriopod-like”’ Arthropod probably related to Arthropleura armata
of Jordan, from the Coal-measures of Saarbrucken, of which similar
fragmentary remains have been obtained from other coal-fields of
France and in this country. Dr. Calman considers it to be a new
species of Arthropod (incert@ sedis), and names it Arthropleura
Moyseyt after the discoverer, Dr. L. Moysey.

The Council of the Geological Society of London so lately as

192 Correspondence—R. L. Sherlock—E. M. Anderson.

February 19, 1915, awarded him the Lyell Geological Fund in
recognition of his valuable work on the fossils of the Derby and
Nottinghamshire Coal-field, including his contribution to the
recently published Geological Survey memoir on that district.

That so valuable a life as that of our friend Dr. Lewis Moysey
should have been sacrificed in so sad and tragic a manner, though in
the service of his country, only increases our sorrow for his
premature loss to science and to his personal friends, by whom he
was greatly valued. |

K. A. IN. A.

CORRESPONDENCE.

SEW icig ceed
“RLINT-MEAL” FROM THE BRITISH CHALK.

Srr,—I should be greatly obliged if any of your readers would
send me properly localized samples of flint-meal from the British
Chalk, other than the 6. mucronata zone of Norfolk, of which I have
plenty. Failing flint-meal, weathered chalk containing foraminifera
is useful provided its horizon is known.

R. L. SHeRzock.

GEOLOGICAL SURVEY,
JERMYN STREET, 8.W. 1.
February 25, 1918.

A NOTH ON ISOSTASY.

Sir,—A rather important consideration has, I think, been over-
looked by Dr. A. Morley Davies (see Gror. Mae. for March, p. 125).
In estimating the amount of subsidence that must ensue ‘‘if the
isostatic adjustment is perfect and immediate” after a sea of
depth d has been filled to the surface with sediment, we must take
into account not only the weight of sediment but also the weight of
water which flows in over the sediment during the process of sinking.
Allowing for this on the basis of Dr. Davies’ figures, the downward
movement becomes eee To secure equilibrium, with sedimenta-
tion up to sea-level, we have the following equation, where @ is the
total subsidence :—

1:36d + 2°364 = 382.

or the total thickness of sediment = 3:12d, instead of 1:83d as
calculated by Dr. Davies. If we assume for the density of the
substratum what we may agree is the rather unlikely figure of 2°7,
the last result is altered to 4 d.

K. M. AnprERson.

EDINBURGH.
March 11, 1918.

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NEWOOSE RIES. DECADE MIb i VOL. Vi

No. V.—MAY, 1918.

ORG amen ASts Asean Sie eS
REDE Se

J].—TuHe Genesis or Tungsten OR:s.
By R..H. RASTALL, M.A., F.G.S.

HE exploitation of tungsten ores on a large scale is of com-
paratively recent development. Till lately the industrial
applications of this metal and its compounds were very limited, and
they were regarded rather in the light of chemical and mineralogical
curiosities. In fact, the tungsten minerals were considered a
nuisance by miners, owing to the difficulty of separating them from
other valuable and equally heavy ores occurring in close association
with them. Sodium tungstate was manufactured to a certain
extent and used as a mordant in dyeing and for rendering textile
fabrics fireproof, and tungstic oxide was sometimes employed in the
making of yellow glass. About the year 1905 a demand arose for
the metal for electric lamp filaments, but at the present time by far
the most important application is in the metallurgy of steel. The
addition of a small quantity of tungsten, not more than 7 or 8 per
cent, together with about 5 per cent of chromium, has a remarkable
effect on steel, rendering it both hard and tough and suitable for
high-speed cutting tools. Since the beginning of the War the
demand for the ores for this purpose has enormously increased, as
also has the price; new sources are being sought for and opened up
in many localities; in Colorado and California there was a few
months ago a tungsten boom recalling the gold rushes of the early
days. The resources of various parts of the British Empire are also
being exploited on a large scale, and on its metallurgical side the
tungsten industry is now very largely in British hands, whereas
before the War Germany. absorbed the greater part of the world’s
output of ore. Under present conditions it is naturally very
difficult to obtain complete and reliable figures, but the following
table (p. 194) shows approximately the output of tungsten ores
throughout the world for the last few vears. The figures (in tons)
are taken from Zhe Mineral Industry, vol. xxv, p. 741, 1916.
Although the following notes do not claim to contain the results
of any original work, it is thought that a brief summary of our
present knowledge of the genesis, mode of oecurrence, and mineral
associations of the tungsten ores may be of interest to geologists and
mineralogists. The literature of the subject is widely scattered,
largely in foreign publications, and the descriptions in most of the

DECADE VI.—VOL. V.—NO. V. 13

194 R&R. H. Rastall—The Genesis of Tungsten Ores.

standard textbooks are not very satisfactory. Mr. A. M. Finlayson’
has briefly discussed the genesis of the ores from a theoretical point
of view in the Grotocicat Macazine for 1910, giving a large number
of references, and in 1909 the Imperial Institute published a small
monograph on the subject from the practical standpoint,? but no
general account of recent date seems to be available.

1906. 1912. 1913. 1914. 1915. 1916.

United States . ; 844 1,210 1,397 900 2,120 6,780
Argentina : : 300 638 © 539 394 171 700
Bolivia . ‘ : 70 497 564 276 793 920
Peru : : : = 214 300 196 371 400
England. . é 276 193 182 205 360 350
France . : ; 20 230 245 200 200 200
Germany and Austria 60 167 150 220 250 300
Portugal . : b 570 1,330 800 967 1,400 1,600
Spain . : : 200 169 150 84 511 600
Burma . 5 ; oo 1,905 1,732 | 1,868 2,883 4,123
Siam . : : — 108 281 30 297 468
Japan. : ; 40 205 297. 195 439 1,150
Queensland . : 800 860 543 435 640 800
New South Wales . 271 271 209 220 100 146
New Zealand . : 165 165 270 250 249 300
World .- . | 4,000 8,780 |10,000 | 8,000 | 12,000 | 19,000

The element tungsten does not enter into many compounds of
natural occurrence. It belongs to the group of metallic elements
that give rise to acid-forming oxides; tungstic acid forms salts with
several divalent metals, especially iron, manganese, calcium, and lead.
The tungstates of these metals fall into two well-defined groups;
the iron and manganese minerals crystallize in the monoclinic
system, while the others are tetragonal. So far as is known tungsten
does not occur in nature as sulphides or anhydrous oxides; even the
oxidation products of the tungstates are few in number, the only one
that is at all common is tungstic ochre, a yellow powdery substance
sometimes found as a crust on tungstate minerals. It appears to be
a hydrated oxide or hydroxide of a not very definite composition.
The tungstates are remarkably stable minerals, being little affected
by any weathering agents, and in consequence the ores do not
undergo secondary enrichment; on the other hand, they show
a strong tendency to accumulate as shoad and alluvial deposits.

The iron and manganese tungstates, commonly known collectively
to the miner as wolfram, form an excellent example of an isomorphous
series. The two theoretical end-products are ferberite, Fe WO,, and

1 Finlayson, ‘‘ The Ore-bearing Pegmatites of Carrock Fell’’: GEOL. MAG.,
1910, p. 19.

2 “The Occurrence and Utilization of Tungsten Ores’’: Bull. Imp. Inst.,
vol. vii, pp. 170, 285, 1909.

hk. H. Rastall—The Genesis of Tungsten Ores. 195

hiibnerite, MnWO,. These two molecules may mix in any pro-
portion. The varieties rich in manganese are perhaps the more
common, Since every possible gradation of composition is known,
it has been proposed by Messrs. Hess and Schaller? that arbitrary
divisions shall be made as follows: all varieties with not more than
20 per cent of the manganese molecule are called ferberite and those
with not more than 20 per cent of the iron molecule hiibnerite,
while intermediate varieties are called wolframite. In the following
pages, however, the names wolfram or wolframite are used in the
miner’s sense to include all varieties of iron and manganese
tungstates.

The tetragonal tungstates include scheelite, CaWO,, and stolzite,
PbWO,. Of these the former is by far the more common and
important. A new mineral from Northern Queensland, chillagite, is
of interest, since it is an isomorphous mixture of the stolzite
molecule, PbWO,, and the wulfenite molecule, PbMoO,, thus
emphasizing the paragenetic connexion which undoubtedly exists
between tungsten and molybdenum. The close mineralogical
association between these two elements will appear later. Some
varieties of both wolframite and scheelite contain a little copper, but
this does not seem to be of much significance.

At this point it becomes necessary as a matter of convenience to
anticipate somewhat and to state that the tungsten deposits can be
most satisfactorily described under four headings, as follows :—

(a) Primary wolframite ores with cassiterite.

(6) Primary wolframite ores without cassiterite.

(ce) Primary scheelite ores.

(d) Secondary (detrital) tungsten deposits.

The justification for this classification will appear in later sections of
this paper.

Part I: Wotrramite Ores with CassItERITvE.

The tungsten ore deposits of the British Isles have lately been
described very fully in a special memoir of the Geological Survey,’
hence it is unnecessary to enter into a large amount of detail
concerning them. In Cornwall the principal ore is wolframite, in
Cumberland scheelite. The primary wolframite ores of Cornwall are
of great interest from the theoretical point of view, since they afford
an admirable example of the wolframite-cassiterite association. The
primary ores of Cornwall are clearly of what is generally known as
pneumatolytic origin, being associated with other minerals and rock-
types characteristic of this phase of igneous action. It will,
however, be pointed out in the general discussion of the genesis of
these ores in a later section that the term pneumatolysis has been
somewhat overworked in this connexion, and as commonly employed
it really comprises two quite distinct classes of phenomena, or rather
phases of igneous activity.

1 ** Colorado Ferberite and the Wolframite Series’’?: Bull. 583, U.S. Geol.
Surv., 1914, p. 37. 9

2 Special Reports on the Mineral Resources of Great Britain, vol. i:
Tungsten and Manganese Ores (Mem. Geol. Surv.), 1915.

196 =. H. Rastall—The Genesis of Tungsten Ores.

The wolframite ores of Cornwall are always in association with
eranite intrusions; they occur in the granite itself, in pegmatite
dykes, in lodes, and disseminated in a more or less irregular way in
certain rocks in the immediate neighbourhood of the granite; the ~
association with greisen is particularly close, and is of much genetic
significance with regard to the mode of distribution of the ores.

It is quite clear that the pegmatite veins carrying wolfram are
earlier than either the lodes in the country rock or the greisens.
The list of minerals found in connexion with the wolfram ores is
long, but the following are the most characteristic and significant :
cassiterite, mispickel, chalcopyrite, tourmaline, topaz, and fluorspar.
In the greisens of St. Michael’s Mount and elsewhere uranium
minerals also occur in association with wolfram.' The importance of
this fact will be referred to again later. ‘’o sum up, the whole
mineral association forms an excellent example of the tin-tungsten-
fluorine paragenesis, which, as will be seen in the sequel, is so widely
spread in many parts of the world.

In connexion with the tourmaline granites of Brittany wolframite
is found along with cassiterite, molybdenite, mispickel, chalcopyrite,
blende, and fluorspar. The ores occur in a network of veins (stock-
work) in the granites, near their contact with mica-schists. The
resemblance of this mineral assemblage to that found in Cornwall is
obvious, and both evidently form part of one petrographical province
from the point of view of the metallic contents of the magma, and
both are characterized by the presence of fluorine and boron among
the non-metallic constituents.

Although so far as is known the German resources of tungsten
ores are but small, the occurrences are of considerable interest, and
vood descriptions, have been published. The principal output is
from the well-known mining district of the Erzgebirge in Saxony
and Bohemia. The ancient crystalline rocks of the fractured district
between Dippoldiswalde and Tenlitz are penetrated by great masses
of quartz-porphyry of Permian age (Teplitz quartz-porphyry); into
this are intruded domes and bosses of granite of somewhat later date.
The rocks surrounding the granite are highly mineralized, and in
particular the quartz-porphyry, above the granite intrusions, is more
or less converted into greisen and penetrated by innumerable veins
and stringers carrying a great variety of ores. The districts richest
in mineral veins are those of Altenberg, Zinnwald, Graupen, Khren-
friedersdorf, Geyer, Eibenstock, and Johanngeorgenstadt. At
Altenberg the ores occur in the form of a stockwork in the quartz-
porphyry above the granite dome to the depth of about 750 feet.
The mines of Zinnwald are said to be very rich in wolfram, and are
also worked for lepidolite. Here the veins are in the quartz-
porphyry and run parallel to the upper surface of the granite dome.
The principal minerals are wolfram, scheelite, tinstone, arsenopyrite,
galena, blende, chalcopyrite, tourmaline, topaz, and apatite. The
impregnation with tin and other ores occurred before the last aplitic
phase of the granite intrusion. At Ehrenfriedersdorf many tin-
wolfram lodes of a similar type occur in mica-schist. The whole

1 The Geology of the Land’s End District (Mem. Geol. Surv.), 1907, p. 53.

kh. H. Rastall—The Genesis of Tungsten Ores. 197

mineralization here, as in Cornwall, is closely connected with the
pneumatolytic phase of the Hercynian granite intrusions, and shows
very clearly the genetic association of tungsten with tin and the
highly volatile elements, fluorine, boron, and lithium.

Although the mines of the Erzgebirge in Saxony and Bohemia
figure very largely in German mining literature and in textbooks,
their yield of tungsten ores does not appear to be large, so far as is
known. In 1912, the last year for which official statistics are
available, the output for the kingdom of Saxony is stated to be
101 tons, while no other German state appears to have produced any.
In the same year the Austrian Empire is said to have produced only
66 tons. It is believed that most of the wolfram ores were obtained
by working over the old tin dumps. Nothing definite is known as
to the extent of the supplies still available, but they are probably
not very large. It is of course impossible to place great faith in the
reliability of German statistics in connexion with any product
connected with war preparations, but in this instance the figures
may be correct, since in the years before the War Germany imported
at least half of the world’s total output of tungsten ores. Hence the
reserves at hand were probably considerable.

Besides Great Britain the only other European producer of much
importance is Portugal, although Spain also supplies a certain amount.
In both these countries the ores are associated with cassiterite,
belonging therefore to the group now under consideration. According
to Granell* wolfram ores, usually accompanied by cassiterite, occur
in a zone consisting of granite intruded into crystalline schists and
Cambrian sediments, beginning in Galicia and extending through
Northern Portugal, Zamora, Salamanca, and Caceres, and ending
where it is cut off abruptly by the great Guadalquivir fault. There
is also a similar mineral association in the mountain chains of Central
Spain, in the province of Toledo, at Mijas near Malaga, and in the
Almagrera Mountains; the latter was the locality of the original
manganese-free ferberite, first described by Breithaupt. Little
information is available as to the details of the wolframite ore-
deposits of Spain and Portugal, but they do not seem to present any
special features of interest, and a large part of the output is
apparently alluvial. In the Sierra de Estrellain Portugal wolframite
occurs in rich lodes up to 4 inches wide, associated with cassiterite
and arsenopyrite.

In the Black Hills of Dakota wolframite oceurs in two distinct
genetic types:

1. With tinstone, as at Etta Knob and Nigger Hill.

2. With siliceous gold-ores.

The ore-deposit of Etta Knob is very remarkable, and in some ways
unique. It consists of a vertical pipe of pegmatite some 60 yards
in diameter, containing in addition to quartz, felspar, and mica also
eassiterite, wolframite,molybdenite, arsenopyrite, tantalite, columbite,
apatite, beryl, and spodumene, the latter in crystals over 30 feet
long. The characteristic elements here are evidently tin, tungsten,

’ Granell, Boll. Soc. Esp. Hist. Nat., vol. ix, p. 81, 1909, and Zeits. fiir
Kryst., vol. 1, p. 472, 1911.

198 R&. H. Rastall—The Genesis of Tungsten Ores.

tantalum, niobium, and lithium.!' There are besides a great number
of minerals of metamorphic origin, and pneumatolytic action seems
here to have been very intense.

Somewhat similar to the foregoing is the well-known occurrence
of eryolite at Ivigtut in Greenland, which also contains cassiterite
and wolframite. The cryolite-bearing mass is about 500 feet long
and from 100 to 180 feet wide, lying in granite, granite-porphyry,
and gneiss. In the central portion of the mass cryolite predominates,
with blende, galena, and chalcopyrite. The marginal portions, which
are of pegmatitic character, consist of quartz, felspar, wolframite,
cassiterite, molybdenite, and columbite. Fluorite is found in small
quantity, but boron minerals are absent. This mass must be
regarded as a special facies of the tin-wolframite pegmatite,
characterized by tantalum, niobium, and an enormous excess of
fluorine.

Wolframite deposits occur on a large scale in a zone of country
stretching from Tenasserim (Lower Burma) along the western side
of the Malay Peninsula through Perak and Selangor. The Tavoy
district of Burma and the Federated Malay States are now important
producers; according to the latest statistics available Burma has
now the second largest output of any country in the world.

In the Tavoy district ® numerous granite masses are intruded into
the sedimentary rocks of the Mergui Series. These, which are of
unknown age, consist of quartzites, quartzitic conglomerates, and
schists, the last being often graphitic. The igneous rocks, for the
most part biotite granites, contain tourmaline and cassiterite as
accessories, The wolfram lodes are quartz veins running out from
the granites into the country rock; the chief minerals are quartz and
wolframite, which alone occur in any large quantity. ‘The other
minerals present are cassiterite, molybdenite, arsenopyrite, chalco-
pyrite, bismuthite, galena, and tourmaline. A very characteristic
feature is the almost universal occurrence of columbite. According
to their mineral composition the lodes can be classified into three
groups—

1. Wolframite-quartz lodes.

2. Cassiterite-quartz lodes.

3. Wolframite greisen.
Of these the first is by far the most important, the second and third
groups being apparently rare, but the country is still very im-
perfectly explored.

From a generalization of the published descriptions of the Tavoy
area if may be inferred that the mineral assemblage is specially
characterized by wolframite, cassiterite, molybdenite, arsenopyrite,
and columbite.

Little is apparently known of the intervening Siamese territory
to the south of Tenasserim, although some ore is now exported, but
the Federated Malay States are large producers of wolframite as well

1 Hess, Bull. 380, U.S. Geol. Surv., 1909, p. 149.

2 Ussing, Danmark Geol. Unterség., ser. 1, No. 12, p. 97; Baldauf, Zeits.
fiir prakt. Geol., vol. xviii, p. 432, 1910.

3 Bleeck, Rec. Geol. Surv. India, vol. xliii, p. 48, 1913.

R. H. Rastall—The Genesis of Twngsten Ores. 199

as of tin-ore, especially Perak and Selangor. The mining in these
States, as in Burma, is very largely alluvial, but the minerals are
also worked in situ in the granites. ‘he tungsten occurrences have
been well described by Mr. Scrivenor.' The prevailing rock is
a biotite-hornblende granite, locally rich in tourmaline and cassiterite.
‘he other minerals associated in the lodes are arsenopyrite, chalco-
pyrite, fluorspar, and topaz, with occasionally sapphire and thorium-
cerium minerals. In Selangor the richest shoots of wolfram ore are
generally found at the contact of granite and schist; where the lodes
traverse the schists they contain fairly pure wolfram, on the contact
they contain mixed ore, while within the granite they become richer
in tin and poorer in wolfram. In this area scheelite deposits are also
abundant, as will be described in a later section ; the scheelite appears
to be genetically connected with the wolfram lodes, and is probably
derived also from the granitic magma under somewhat differing
conditions.

The Seward Peninsula of Alaska affords an interesting example
of a highly mineralized region of the type now being considered.’
The country rock consists of quartzite, slate, and especially limestone
of Paleozoic age, probably Carboniferous. These sediments are
intruded by granite bosses and by quartz-porphyry dykes; the
metamorphism thus produced is very intense, especially in the lime-
stones, which contain many newly-formed minerals rich in boron and
fluorine, such as tourmaline, axinite, danburite, vesuvianite containing
boron, and other peculiar ty pes.

Wolframite occurs in association with cassiterite in two different

ways. On Cassiterite Creek the quartz-porphyry dykes intruded
into the limestone are tin-bearing in depth. The tin-ore and
wolframite occur as veins and stringers in the dykes, associated with
arsenopyrite and pyrite. Blende and galena are less common, while
molybdenite is local. The gangue minerals, besides quartz, are
fluorite, topaz, and zinnwaldite. ‘There are also cassiterite-wolfram
lodes in the limestone; these lodes appear to be pegmatitic in origin,
as they contain quartz, felspar and mica, fluorite and topaz; the
other metallic minerals are chalcopyrite, pyrrhotite, blende, and
galena.

Another remarkable occurrence is a wolframite-topaz lode, with
galena and stannite, on Lost River. The gangue consists of purple
fluorite and radial topaz. The presence of some silver is shown
by assays.

From the chemical point of view the most striking feature of this
region is the abundance of boron, which has led to the formation of
many minerals containing that element, of which the most interesting
are paigeite and hulsite, two new iron-magnesia-tin-boron minerals.
In this region boron seems to be in excess of fluorine, an unusual
occurrence.

The wolframite output of Queensland comes from the northern

' Paper on Tungsten Ores, read before the F.M.S. Chamber of Mines at
Ipoh, March 25, 1916 (no place of publication or date).

2 “*The Geology of the Seward Peninsula Tin Deposits,’’ by A. Knopf,
Bull. 358, U.S. Geol. Sury., 1908.

200 R. H. Rastall—The Genesis of Tungsten Ores.

part of the colony, from the Herberton tin-field, from the Etheridge
mineral field, from Mount Carbine, Bamford, and other areas. In the
Herberton district the country rock consists ‘of highly metamorphosed
sediments, including quartzite, greywacke, and shales, intruded by
biotite and hornblende granite, quartz porphyry, and felsite. Lodes
occur in all of these, containing a considerable variety of minerals,
including cassiterite, wolframite, bismuthine, antimonite, chalco-
pyrite, galena, magnetite, tourmaline, topaz, and fluorspar. In the
Hodgkinson field wolframite and molybdenite occur in quartz veins
in a grey biotite granite. At Mount Carbine slates and schists are
penetrated by batholiths of porphyritic biotite-granite. In connexion
with this are pegmatite dykes and interlacing veins forming lodes up
to 6 feet wide. The pegmatites consist of quartz-felspar rock with
tourmaline, some muscovite, and a little bery]. The metallic minerals

are cassiterite, wolframite, arsenopyrite, and molybdenite. The

wolframite appears to be more closely connected with the felspar
than with the quartz. One block of wolframite was found weighing
6 tons. There is also some scheelite.

In the Bamford district the rocks are mainly igneous, both volcanic
and intrusive. Wolframite occurs as an original constituent in
biotite-granite, and also in pegmatites and greisens in connexion
with the granite. A large number of minerals has been observed
here; the chief are: wolframite, bismuth (both native and as sulphides,
carbonates, and oxides), molybdenite, pyrite, chalcopyrite, blende,
and galena; cassiterite has been found, but it is not very common.
Of much interest also are ilsemannite, stolzite, and the new mineral
chillagite, previously mentioned as an isomorphous mixture of lead
tungstate and lead molybdate. The ore-deposits are mainly in the
form of pipes of white quartz, with wolframite and molybdenite ;
vugs are seen up to 20 feet in diameter, containing bismuth, fluorite,
and some sulphides; the smaller vugs are rich in wolfram, while the
larger ones are poor. These vugs are possibly due to stoping along
fissures. Although the form of the wolfram pipes is somewhat
unusual, they do not differ in any essential feature from the common
type of wolfram-molybdenite pegmatites formed by solidification of
the last residues of a granitic magma in which these elements have
been segregated by differentiation or concentration, whichever word
is preferred in this connexion.

From the published descriptions of the Queensland mines it appears
that a large proportion of the present output comes from shoad
deposits, which are locally described as alluvial: This material does
not appear, however, as a rule to have been transported for any
distance, but rather to be a true residual deposit.

Wolframite is also found in the tin area of Mount Bischoff in
Tasmania. Here quartz-porphyry dykes, intruded into Paleozoic
sediments, have undergone intense pneumatolytic metamorphism,
being largely replaced by secondary minerals, including cassiterite,
wolframite, arsenopyrite, pyrrhotite, tourmaline, topaz, and fluorite.
Perhaps the most striking feature here is the great. development of
topaz in the altered dykes.

The extraordinarily rich lodes of the provinces of Oruro and Potosi

kh. H. Rastall—The Genesis of Tungsten Ores. 201

in Bolivia have long been worked on a very large scale for tin and
silver, but lately there has been a great development of wolfram
mining in this area. In 1916 a very active tungsten boom began in

Bolivia, as elsewhere, and the output is now very large. ‘The lodes
are connected with masses of rhyolite and dacite, these being of the
nature of laccolithic intrusions rather than flows. The gangue
minerals are quartz, barytes, and carbonates ; the ores in depth are
mainly sulphides, together with cassiterite and wolframite. The
metals present in the form of sulphides are iron, lead, zinc, copper,
antimony, bismuth, and silver; tin sulphide (stannite) i is also found,
and in the gossan it has been converted into wood-tin. Original
eassiterite and wolframite represent the primary oxidic ores, but in
the gossan there are many oxidized minerals, as well as native silver
and silver chloride in great quantities. Of special interest are three
minerals, argyrodite, franckeite, and canfieldite, containing the
exceedingly rare element germanium. It is evident, therefore, that
the tin-wolfram lodes of Bolivia form an aberrant and in some
respects transitional type; fluorite and tourmaline certainly do occur,
but they are quite rare, and pneumatolytic minerals are for the most
part absent. The whole mineral association shows a much closer
approach to the sulphide type than is usual in tin-bearing deposits.

The tin-wolfram-veins of Mexico (Durango, Guanajuato, and San
Luis Potosi) show some affinity to those of Bolivia; they are
associated with rhyolites, and the principal minerals in addition to
cassiterite and wolframite are native bismuth, specular iron-ore, and
durangite (a sodium-aluminium arsenate with fluorine). ‘Topaz is
found, but no tourmaline. These veins appear to be of very recent
date. In this case there are no sulphides, and it is perhaps per-
missible to regard them as an ultra-oxidic type, specially characterized
by fluorine. “The relationship to other types of tin-wolfram ores is
not clear.

Summary oF Parr I.

’ A careful consideration of the facts set forth in the foregoing pages
shows that the ore-deposits of the wolframite-cassiterite type result
directly from the cooling of granitic magmas, and the metals, tin and
tungsten, are integral and characteristic constituents of those magmas.
In many instances cassiterite is -known to occur as a_ primary
constituent of the granite; less commonly wolframite is found in
a similar way. As a rule, however, these minerals become con-
centrated in that fraction which- is highly volatile and escapes from
the central portions of the intrusion, forming pegmatites and greisens
in the granite itself and in the surrounding rocks. This tendency is
doubtless accounted for by the fact that both tin and tungsten form
highly volatile compounds with fluorine. The formation of cassiterite
by the action of water on tin fluoride was long ago experimentally
verified by Daubrée. According to Roscoe and Schorlemmer, tungsten
hexafluoride is a gas at temperatures above 19°C. under normal
pressure. All the evidence from the relative distribution of
eassiterite and wolframite in lodes, goes to show that the latter
is more volatile than the former, since it usually travels further
from the margin of the granite; tin-wolfram lodes pass laterally

202 kh. H. Rastall—The Genesis of Tungsten Ores.

and continuously into wolfram lodes and these again into pure
quartz veins.

When the distribution of these minerals is studied in detail if is
seen that the original metallic minerals of the granites and the ore-
minerals of the pegmatites, greisens, and quartz lodes are of common
genesis. They all arise as products of the crystallization of the
differentiated magma. There is, therefore, in this case, no real
distinction between magmatic segregations and vein - deposits.
Consequently, the classification so prevalent in German textbooks
into syngenetic and epigenetic deposits here breaks down. The
difference is mainly one of time, or as it may be otherwise expressed,
a difference of phase.

The formation of these deposits, then, may be summarized as
follows :—

Ist phase: Concentration within the magma of the metallic
constituents in combination with the volatile elements,
especially fluorine and boron.

2nd phase: Separation from the crystallizing granite of the com-
pounds thus formed, and escape of the same through fissures.

3rd phase: Chemical reactions between the compounds in the
escaping gases or solutions, leading to the formation of
crystallized ore and gangue minerals.

It is, of course, impossible to draw any hard and fast line between
these different phases; they are all parts of one continuous process,
and in many instances doubtless proceed concurrently.

Turning now to the mineralogical and chemical side of the question,
we find a marked similarity of composition in all parts of the world.
Although there are local differences in detail, yet it is possible to
enumerate certain minerals of almost universal occurrence in
association with wolframite and cassiterite. Of these the most
characteristic among the sulphides are arsenopyrite and molybdenite.
Chalcopyrite again is common, while blende and galena are more
sporadic. Of the non-metallic minerals, tourmaline, topaz, and
fluorite are characteristic, showing the presence of the highly
volatile and chemically active elements fluorine and boron.

Special interest attaches to the presence in certain localities only
of notable amounts of some of the rarer elements, such as niobium,
tantalum, and uranium. ‘The last, for example, is found in Cornwall,
while columbite is abundant in Burma and in the extraordinary
pegmatitic masses of Etta Knob and Ivigtut. At Etta Knob it is
accompanied by a striking development of lithium minerals. In
Bolivia silver is the most characteristic element. From these and
similar considerations it appears possible to subdivide the tin-
tungsten occurrences into paragenetic sub-types, as follows :—

uranium . . Cornwall.

tantalum and Burma, Etta Knob,
molybdenum, arsenic niobium Tvigtut.

Tungsten, tin bismuth . . Queensland.

SUlVery wey aii) | cha CLIN ara UMMM Olinvilale

R. Bullen Newton—Foraminifera from New Guinea. 203

Furthermore, with respect to the non-metallic elements, some
regions are characterized by excess of fluorine, others by excess of
boron, each giving rise to characteristic groups of minerals, which
indicate the chemical composition of the original magma. The
further significance of these facts will be discussed more fully at
a later stage.

The following table shows the chief minerals found in ten of the
more important wolfram-tin ore-deposits in different parts of the
world :-—

. d (<b) so

as . | & aS) = Sh Wines

— B = A fo] ~ 3 q

3 = 3 2 rie 5. | ce S

S rQ a a a 3 n a

= sy o = fs! q Ba ka i=] a

| = ao | © co) =I Grol aA oy =|

s oa N “4 o o = eS o n

iS) zi 4 & a) = s ay Ss x

Sf ey | eat ee et eS Sl Se ls

Wolframite PAR UN 5:88 Weep 2:0 >So. alles \ Al pcuall ore
Cassiterite x x xe x x x 5 xX x x
Molybdenite a oe | ee Se Se bre Pe a be Il oe
Arsenopyrite Scr vibrate lesen pe Ne abceM o:eh lta be i(liulsce) Allo:
Chalcopyrite me oN Se oe ail ROR oR NSS Tboe ) ae
Galena x |—|x xe x xe x x | —
Blende x x | x {|—]x{/—il—| «x x | —
Pyrite x }/—/—}]—{]x}—|]—}]x;—] x
Bismuth minerals i ee ee
Uranium a : SO oe IS oe ee
Columbite 3 : Spee Wea le) oe X x }|—}]—}]—]}] —
Tourmaline ; ; Flex Sc x x |—|x x X OK ae
Fluorite . ; : Sn eX De es Se eal bc Xs x x
Topaz ‘ : : ae |p Se ae eh oP ioe A ioe Lh Dx) Iie oe

(To be continued.)

I[l.—Foramintrerat ann Nutiiore Scrucrures In soMe TERTIARY
Limestones From New GuInra.
By R. BULLEN NEWTON, F.G.S., Geological Department, British: Museum."
(PLATES VIII AND IX.)

Inrropocrion.

T the request of Professor J. W. Gregory, F.R.S., of Glasgow
University, the following report has been prepared dealing with
some microscopical organisms entering into the composition of certain
limestones from Central New Guinea. The material studied, com-
prising Foraminifera and Nullipore (Lithothamnium) remains, has
been obtained from some rolled limestone pebbles which were
collected in river-beds of the upper reaches of the Fly River by
the Right Hon. Sir William Macgregor, G.C.M.G., during an
expedition carried out in the years 1889 and 1890. Being desirous
that these limestones should be scientifically examined, Sir William

submitted them to the Geological Department of the University

1 Published by permission of the Trustees of the British Museum.

204 R. Bullen Newton— Foraminifera, etc.,

Glasgow in the hope that Professor Gregory and his staff might issue
a statement as to their structural and geological value. In accordance
with this request, therefore, the corals were first examined and
described in a joint paper by Professor Gregory and Miss J. B. Trench,’
while some remarks on the Foraminifera and associated structures
have been postponed for the present occasion. At the time when the
corals were in course of description, the writer was appealed to for
an opinion as to the geological age of one of the pebbles (No. 1),
exhibiting corals and some smaller organisms, although to give aid
in this direction it was necessary to prepare microscopical sections of
the limestone for examination by transmitted ght. It was then
ascertained that the genus Alveolina was of frequent occurrence, as
well as other Foraminifera, chiefly of the Milioline group. According
to Orbigny,? Alveolina originated in Cretaceous times, having been
recorded from the Cenomanian rocks of France; it is, however, much
more typical of the Eocene period, being well ‘known in deposits of
that age as developed in England (Bracklesham Beds particularly),
Europe, Egypt, Madagascar, India, Java, Celebes, New Guinea, etc.
The genus is less abundant in the younger Tertiary formations, while
according to H. B. Brady * two species alone survive in tropical seas
at the present day. ‘The distribution of this genus, therefore, and
its association in the limestone pebble with the Miliolines, so
characteristic of the Bracklesham Beds and corresponding deposits
of the Paris Basin, suggested that the pebble might be attributed to
the Lutetian or Middle division of the Eocene series, a result since
accepted and published in the Gregory and Trench paper previously
referred to (p. 532).

BrsiioGRaPHy.

Several memoirs have been issued on the organic structures of
New Guinea Tertiary rocks, most of which have been recently
reviewed in a paper by the writer,* and although it is unnecessary to
repeat such information it seems desirable to refer again to that part
of the literature which more particularly concerns the occurrence of
Alveolina in that country. The first mention of Alveolina in the
limestones of New Guinea was made by Dr. K. Martin® in 1881, from
material obtained in north-west regions, the generic determination
having been confirmed by Schwager, who, moreover, considered that
the specimens were related to A. spherica (Fortis), the equivalent of
A. melo (Fichtel & Moll), a characteristic Miocene species, besides
being known from older Tertiaries as well as from recent seas. The

1 ** Hocene Corals from the Fly River, Central New Guinea’’: GEOL. MAG.,
1916, pp. 481-8, 529-36, Pls. XIX-XXII.

2 Prodrome Pal. Strat., 1850, vol. ii, p. 185.

> Rep. Voy. H. M.S. ‘‘ Challenger’? : Zoology—Foraminifera, vol. ix, pl. xvii,
figs. 7-15, pp. 221-4, 1884.

+ R. B. Newton, ‘‘ Notes on some Organic Limestones, etc., collected by the
Wollaston Expedition in Dutch New Guinea, from Reports on the Collections
made by the British Ornithologists’ Union Expedition and the Wollaston
Expedition in Dutch New Guinea (1910-13)’’ : Report No. 20, vol. ii, 1916.

* ““Bine Tertiaerformation von Neu-Guinea und benachbarten Insel’’:
Samml. Geol. Reichs.-Mus. Leiden, vol. i, pl. iii, figs. 9-10, p. 70, 1881.

un Terivary Rocks of New Guinea. 205

organism was briefly described and figured as Alveolina sp., and was
said to be associated with Orbitoides, Cycloclypeus, etc., and the
Nullipore Lethothamnium ( Cumulipora) rosenbergr, Martin, now better
known as ZL. ramosissimum of Reuss, which is typical of Miocene
rocks.! The Orbitoides were stated to possess rectangular chamberlets
(rechteckige mediankammern), as seen on the median plane, thus implying
the presence of the Kocene genus Orthophragmina. It is evident
that some confusion must have arisen with the material determined
by Martin to account for such an assemblage of forms, and it seems
fair to suggest that the Alveolina and the Orbitoides belonged to an
Kocene limestone, while the remaining organisms, Cycloclypeus,
Lithothamnium, ete., indicative of a Miocene origin, were, in all
probability, observed in another rovk. Martin first of all determined
this limestone as Tertiary, although a year later? definitely placed
it in the older Miocene and in correlation with similar deposits of
Indo-Pacific countries.

In his 1881 memoir, Martin likewise referred to certain limestones
he had examined from Geelvink Bay localities and from islands off
the south-western end of New Guinea, mostly containing Orbitoides,
a small Mummulina sp., and Lithothamnium rosenbergr. They were
regarded as of Tertiary age, with a resemblance to the older Miocene
rocks of Timor, Java, and Sumatra. The Orbitoides were stated to
belong to the Lepidocycline group of the type of O. gigantea of
Martin, from the Miocene of Java.

Schlumberger subsequently studied the same material as described
by Martin containing the so-called Alreolina sp., which had been
submitted to him by Dr. Wichmann.* He was unable to recognize
the accuracy of Martin’s Alveolina, but regarded the organism as
presenting structures belonging to the genus Lacazina ot Munier-
Chalmas; he therefore described and figured it under the new
specific designation of Z. wichmannt. The author also remarked on
the interest of the discovery since Zacazina had hitherto been
restricted to the younger Cretaceous rocks of Kurope and Palestine,
and now, according to Martin’s interpretation as to the age of the
New Guinea deposits, this genus could be recognized as occurring in
the Tertiaries of that region. Schlumberger also mentioned that the
associated Foraminifera included Rotaline, Miliolide, and a true
Alveolina of the sub-genus Flosculina. Moreover, he had not seen
the assemblage of forms referred to by Schwager (in Martin), the
determinations of which he considered as of doubtful value.

Martin * next identified the presence of Lacazina wichmanni in some
detrital limestones from south-west New Guinea (Setakwa River, etc.)

1 R. B. Newton & R. Holland, ‘‘On some Fossils from the Island of
Formosa, etc.’?: Journ. Coll. Sci. Imp. Univ. Tokyo, Japan, vol. xvii, art. 6,
pl. i, fig. 8, pp. 17-19, 1902.

2 “Neue Fundpunkte von Tertiaergesteinen im Indischen Archipel ”’ :
Samml. Geol. Reichs.-Mus. Leiden. vol. i, p. 178, 1882.

3“ Note sur Lacazina wichmanni, Schlumberger, n.sp.’?: Bull. Soe. Géol.
France, ser. II, vol. xxii, pl. xii, pp. 295-8, 1894.

4 “*Paliozoische, Mesozoische, und Kinozoische Sedimente aus dem siid-
westlichen Neu-Guinea’’: Samml. Geol. Reichs.-Mus. Leiden, vol. ix,
pp. 84-107, iey tite

206 R. Bullen Newton—Foraminifera, etc.,

associated with Alveolina and Nummulina, and on account of its
frequent occurrence he named the limestones ‘‘ Lacazinenkalk” and
considered them as of Eocene age. On the same occasion Martin
also referred to the discovery of Alveolina by Dr. H. A. Lorentz in
the limestones of Mt. Wilhelmina, situated in south-central Dutch
territory at an altitude of more than 13,000 feet or 4,461 metres.
The genus was found accompanying Nummulites, and in consequence
ascribed to the Eocene period.' A still further reference occurs in
Martin’s memoir regarding Alveolina, mention being made of its
identification in the limestones of Digoel River (S.W. New Guinea)
associated with Lepidocyclina and Lithothamnium and stated to belong
to the older Miocene.

The latest notice of importance respecting the occurrence of
Alveolina in New Guinea is to be found in a report by Dr. L. Rutten,’
published in 1914, containing figures and description of a new species,
A. wichmanni, from the Eocene limestones of Dramai Island, Triton
Bay, south-west New Guinea, which is stated to have been associated
with Lacazina wichmanni, Schlumberger. The paleontology of the
older Miocene limestones of New Guinea has rather recently been
studied, and quite independently, by Mr. F. Chapman,* of the
National Museum, Melbourne, and the present writer,* with very
similar results. The principal organisms recognized were various
species of Lepidocyclina, Cycloclypeus, Carpenterra, Lithothamnium
ramosissimum, etc., an assemblage indicative of the Upper Aquitanian,
which represents the oldest stage of the Miocene formation.

Tue LivestonE PEBBLES.

The pebbles submitted for examination are numbered 1, 2, 11, 12,
and 28, the largest being Nos. 1 (90 X 50mm.) and 2 (105 Xx
60mm.), whereas the others are, roughly, about a third of their
size. They consist of slightly different-coloured limestones, which
in connexion with their organic contents are considered to belong to
two different Tertiary horizons: the Eocene and the Miocene.
Being rounded and of water-worn character, they may be termed
rolled-limestone pebbles; and further, having been collected from
river-beds in the upper reaches of the Fly River, their origin
undoubtedly points to the great limestone development which, as
high mountain ranges, runs east and west through the wide central
region of New Guinea.

1 For some unexplained reason this limestone from Mt. Wilhelmina with
Alveolina has been rather recently determined as of Cretaceous age in an
article on ‘‘Papua’’ contained in the Federal Handbook, prepared for the
84th Meeting of the British Association for the Advancement of Science, held
in Australia, 1914, pp. 256, 321.

2 “* Woraminiferen-Fuhrende Gesteine von Niederlandisch Neu-Guinea ”’:
A. Wichmann’s Nova Guinea, vol. vi, ‘‘ Géologie,’’ livr. ii, pl. ix, figs. 1, 2,
p. 45, 1914.

3 “Description of a Limestone of Lower Miocene age from Bootless Inlet,
Papua ’’: Journ. Proc. Roy. Soc. New South Wales, vol. xlviii, pt. ti, pls. vii-i1x,
pp. 281-301, 1914.

4 R. B. Newton, the Wollaston Expedition Report, 1916, previously
alluded to.

in Tertiary Rocks of New Guinea. 207

No. 1. This consists of a cream-coloured limestone of one uniform
tint throughout, and is that previously determined by the writer for
Professor Gregory as exhibiting <Alveolina, Miliolines, and coral
structures, and which was referred to the Middle and Lutetian stage
of the Eocene period. A further examination of this pebble has now
furnished evidence of the presence of Lacazina and Orthophragmina,
so that its geological age seems to be beyond question and, moreover,
it fairly closely corresponds with the ‘‘ Mixen” and “Clibs”’ rocks
of Bracklesham Bay, England, and the ‘‘ Miliolite’’? Limestone of
the Paris Basin, all of which contain Alveolina associated with
Miliolines, and which belong as well to this stage of the Eocene
Series.

No. 2. A cream-coloured limestone, but with deep reddish-brown
veins extending to the centre of the pebble. It contains occasional
Alveolina, Corals, and an abundance of the Nullipore, Lithothamnium
ramosissimum, whilst the absence of Miliolines and Lepidocyclines
may also be noted. Chiefly from the occurrence of the Nullipore, so
peculiarly characteristic of the Miocene limestones of Europe and
Far Eastern countries, this pebble is regarded as belonging to that
division of the Tertiary system.

No. 11. Is cream-coloured, but intersected by thin dark veinings.
It resembles No. 1 in possessing similar coral structures, of which it
is mainly composed. Miliolines are also present, the polished surface
exhibiting a transverse section of Pentellina like saxorum. No
Alveolines are discernible, but the assemblage denotes an HKocene
origin for this pebble.

No.12. A yellowish cream-coloured limestone containing Miliolines,
Textularia, Carpenteria conordea, etc., and Lithothamnium ramosissimum,
the latter suggestive of its Miocene age.

No. 28. This is mainly composed of a stellate coral structure,
although its narrower end reveals some minute Foraminifera,
especially an Alveoliniform-looking organism, occurring as transverse
and longitudinal sections on the polished surface, which represents
Lacazina wichmanni, a New Guinea fossil of known Eocene age.

Organisms contained in the Pebbles.
FORAMINIFERA.
ALVEOLINA WICHMANNI, Rutten. (PI. VIII, Figs. 1a, 2a, 3, 4a, 5, 6.)

Alveolina wichmanni, Rutten, Wichmann’s Nova Gwinea, vol. vi, ‘‘ Géologie,’’
pt. ii, pl. ix, figs. 1, 2, p. 45, 1914; Samml. Geol. Reichs.-Mus. Leiden,

ser. I, vol. ix, pl. xxvi, figs. 3, 4, and pl. xxvii, fig. 2, pp. 315-18, 1914.
This is an Kocene species having been originally described from
the limestones of south-west New Guinea (Triton Bay) and after-
wards from the Island of Celebes. It presents a narrow, tapering,
and spindle-shaped axis composed of few and often irregularly formed
layers which vary in number from nine to fourteen. hose forms
with more regularly disposed layers are represented by Figs. 3 and
4a, whereas Figs. la and 2a show a greater irregularity and thus
more closely approach the type. A transverse section displayed on
the polished surface of the pebble, Fig. 6, exhibits a series of

\

208 kh. Bullen Newton—Foraninifera, etc.,

apertures which represent the longitudinal channels that perforate
the organism throughout its longer axis. A good longitudinal view
of a weuthered specimen exposing a partial interior is illustrated by
Fig. 5, in which the margins of the layers are to be observed together
with the closely set, external, transverse striations. Miliolines of
the Quinqueloculine type and other Foraminifera accompany this
species, see Figs. 16, 2, and 40 of Plate VIII.

Dimensions.—Length 38-8, width 1-2} mm.

Occurrence.—Pebble No. 1.

Distribution.—Kocene deposits of New Guinea and the Island of
Celebes. ;
ALvEotIna sp. (PI. IX, Fig. 6a.)

A longitudinal section of this genus occurs in No. 2 pebble
associated with Lithothamnium ramosissimum. It is rounded at the
poles and not fusiform as is the case in A. wichmanni, being most
nearly related to A. melo (Fichtel & Moll), which, according to Brady,’
ranges from Hocene to Recent seas. The presence of the Nullipore
in this pebble strongly supports its Miocene origin.

Dimensions.—1 by 4mm.

Occurrence.—Pebble No. 2.

Lacazina wichMannt, Schlumberger. (Pl. IX, Figs.-1, 2, 3a.}

Alveolina sp., cf. A. spherica (Fortis), Martin & Schwager: Samm]. Geol.
Reichs.-Mus. Leiden, vol. i, pp. 70-83, pl. iii, figs. 9-10, 1881.

Lacazina wichmanni, Schlumberger, Bull. Soc. Géol. France, ser. III,
vol. xxii, pl. xii, pp. 295-8, 1894; Rutten, Wichmann’s Nova Guinea,
vol. vi, ‘‘ Géologie,’’ pt.-ii, pl. vili, figs. 8, 9, p. 44, 1914.

The form here referred to is of frequent occurrence in No. 1 pebble,
and is also found in No. 28 pebble accompanying a stellate coral
structure. Specimens showing both longitudinal and transverse
sections are well exposed on the polished surfaces of the limestones,
and they resemble Martin’s figures of <Alveolina sp. found in the
north-west coastal regions of New Guinea, which was determined by
Schwager as being related to A. spherica (Fortis), the equivalent of
A. melo (Fichtel & Moll), a characteristic Miocene species. At
a later date, however, Schlumberger studied Martin’s material -and
recognized the supposed Alveolina sp. as a new species of Lacazina,
Munier-Chalmas (Bull. Soc. Géol. France, ser. m1, vol. x, p. 472,
1882, type= Alveolina compressa, Orbigny), a genus hitherto restricted
to the younger Cretaceous rocks of Europe and Palestine.

The chief features of interest respecting ZL. wichmanni are its
possession of a spherical initial chamber succeeded by chambers the
walls of which are alternately open below and above the poles
throughout its growth. The chambers are also divided internally
by numerous longitudinal ribs radiating from the external wall of
each chamber and often appearing to reach the inner surface of the
succeeding layer. These characters are more or less expressed in the
present examples, although the delicate openings of the chamber
walls are most difficult to trace, and their existence is only obscurely
indicated. The radio-longitudinal ribbing appears also to be finer

1 Challenger Report: Foraminifera, 1884, pl. xvii, figs. 13-15, p. 223.

in Tertiary Rocks of New Guinea. 209

than in Schlumberger’s illustrations, but if our figures are subjected
to a higher magnification a coarser effect is produced which yields
a considerable resemblance to the type. First regarded as Tertiary,
then Miocene, Martin’ finally admitted this organism as of Eocene age,
more particularly as it was now known to have been found with
Nummulites in the rocks of south-western New Guinea (Setakwa
River). On account of its great frequency in the limestones of
New Guinea, Martin established the name Lacazinenkalk. Miliolines
are in close association with this genus, forms being clearly depicted
in Fig. 3 of Plate IX.

Dimensions.—From 1 to 4 mm. in diameter.

Occurrence.—In pebbles Nos. 1 and 28.

Distribution.—Species found only in New Guinea rocks.

OrrHopHRacmiINA sp. (Pl. IX, Fig. 4.)

A fragmentary example of this genus is to be observed on the
polished surface of No. 1 pebble. It is merely a portion of a
horizontal section measuring about 8 mm. across the disc, exhibiting
remains of eight or nine of the later annulations which enclose
numerous rectangular chamberlets characteristic of Orthophragmina,
an Kocene genus founded by Munier-Chalmas* in 1891, on the type
of Michelin’s Orbitolites pratt, from the Eocene of Biarritz, France.

From this single imperfect specimen and with no knowledge of its
embryonic characters, it is not possible to venture on a specific
determination. Nevertheless, so far as the evidence goes, it may be
stated to show resemblances to the published figures of O. pratti,$
which includes Giimbel’s Orbitoides (Discocyclina) papyracea, non
Boubée,* an Kocene form of Kurope and other countries.

Oceurrence.—VPebble No.1; associated with Alveolina, Lacazina,
Miliolines, etc.

CARPENTERIA CoNOIDEA, Rutten. (Pl. IX, Fig. 5.)
Carpenteria conoidea, Rutten, Wichmann’s Nova Guinea, vol. vi, ‘‘ Géologie,’’
pt. ii, pl. vii, figs. 6-9, p. 47, 1914.

Dr. Rutten has described an erect form of Carpenteria from the
older Miocene deposits of northern New Guinea to which the present
specimen may be referred. ‘The fossil in question is the large
central organism represented in Fig. 5, in which is displayed a
longitudinal view of the interior showing a segmental structure
composed of thick and porous walls, and a well-marked conoid-apical
region, from which succeeds its later development widening
appreciably to the base. The chambers, especially those observed
near the base, are of crescentic form resembling Glodigerina.

1 ** Paldozoische, Mesozoische, und Kanozoische Sedimente siidwestlichen
Neu-Guinea’’: Samml. Geol. Reichs.-Mus. Leiden, vol. ix, p. 104, 1911.

2 Htude du Tithonique, du Crétacé, et du Tertiaire du Vicentin, 1891,
Thése de doctorat, p. 18.

3 Schlumberger, Bull. Soc. Géol. France, ser. IV, vol. iii, pls. viii, ix, p. 274,
1903.

4 Gimbel, Beitrage zur Foraminiferen der Nordalpinen Hocdngebilde, 1868,
ples sleep wll

DECADE VI.—VOL. V.—NO. V. 14

210 R. Bullen N ewton—Foraminifera, etc.,

This organism is associated with Zeartularia, Quinqueloculine, ete.,
and Lithothamnium ramosissimum, the presence of the latter more
particularly suggesting a Miocene origin.

Dimensions.—Length 2, width 1mm.

Occurrence.—Found in No. 12 pebble.

Distribution.—Known only in the Miocene rocks of New Guitea.

’ Mintorines. (Pl. VIII, Figs. 1b, 26, 46; Pl. 1X, Fig. 30.)

Milioline Foraminifera associated with Alveolina, Lacazina, etc.,
are abundant in No. 1 Pebble. The more striking form, as seen in
the sections and represented by our photographic figures, exhibits
transversely plicated chamber walls, thus suggesting a relationship
to Pentellina saxorum (Orbigny), a fossil of frequent occurrence in
the Miliolitic Limestone of Paris and the ‘‘Clibs” and ‘‘ Mixen”
rocks of the Bracklesham Beds of England, all of which belong to the
Lutetian or Middle Eocene horizon.

It is interesting to note that Miliolines with similarly associated
forms have been reported from the Eocene limestones of the Island
of Celebes by Dr. Rutten.’

Dimensions.—14 mm. in diameter.

Occurrence.—In No. 1 pebble.

PLANTH (NULLIPORE).
LirHorHaMNIUM RAMosIssIMUM, Reuss. (Pl. IX, Figs. 64, 7.)

Nullipora ramosissima, Reuss, Nat. Abhand]. Haidinger, vol. ii, pt. i, pl. iii,
figs. 10, 11, p. 29, 1848.

Lithothammum ramosissimum, Giimbel, Abhandl. k. bayerischen Akad.
Wiss. Miinchen, vol. xi, pt. i, pl. i, fig. 1, p. 34, 1871.

Cumulipora rosenbergi, Martin, Samml. Geol. Reichs.-Mus. Leiden, vol. i,
pp. 12 14, 64, pl. iii, fig. 7, 1881.

Lithothamnim ramosissimum, Nishiwada, Journ. Coll. Sci. Imp. Univ.
Tokyo, vol. vii, pt. iii, p. 236, pl. xxix, figs. 1-4, 1894.

L. (Cumutlipora) rosenbergi, Newton & Holland, Journ, Geol. Soc. Tokyo,
vol. vii, No. 81, p. 22, 1900.

LL. ramosissumum, Néwton & Holland, Journ. Coll. Sci. Imp. Univ. Tokyo,
vol. xviii, pt. vi, p. 17, pl. i, fig. 8, 1902; Chapman, Journ. Proc. Roy.
Soc. New South Wales, vol. xlviii, p. 286, 1914; R. B. Newton, Reports
Coll. Brit. Ornith. Union Wollaston Exped. Dutch New Guinea, vol. ii,
Rep. No. 20, pl. i, p. 17, 1916.

This well-known calcareous alga, first recorded from the European
Miocene and so abundantly represented in the same formation as
developed in Far Eastern countries, is of prolific occurrence in No. 2
pebble. Its elegant structure, well seen in Fig. 7, includes the
arrangement of ‘the rectangular tissue cells within the regularly
disposed annulations of growth forming the branches. More massive
forms of the genus are also present in the limestone, one being
_ observed at the base of the section illustrated by Fig. 60 in close
proximity to the branches that have been further enlarged in Fig. 7.

The specimen is associated with an Alveolina (Pl. IX, _ 6a)
having a probable relationship to the Miocene A. melo.

1 «* Studien iiber Foraminiferen aus Ost-Asien’’: Samm]. Geol. Reichs.-Mus.
Leiden, vol. ix, pp. 308-10, 1914.

Lose
soe

Nee
Se

aS:

x
set
By,

Grou. Maa., 1918.

P. Dellman, photo.

TERTIARY FORAMINIFERA,

NEW

Prate VIII.

R. B. Newton, direvit.

GUINEA.

a

in Tertiary Rocks of New Guinea. 21.

Dimensions.—Rather more than 2 mm. in length.

Occurrence.—In pebble No. 2.

Distribution. — Europe and Indo-Pacific regions — Formosa,
Philippines, Japan, Christmas Island, Borneo, Sumatra, Celebes,
New Guinea, Australia, etc.; and of Miocene age.

Resvits.

The more important facts connected with the examination of the
limestone pebbles prove that they may be referred to two geological
horizons, viz. the Eocene and Miocene. The Kocene fossils, found
in pebbles Nos. 1, 11, and 28, comprise: <Alveolina wichmanni, Laca-
zina wichmanni, Orthophragmina sp, and cf. Pentellina saxorum.
The Miocene fossils, restricted to Nos. 2 and 12 pebbles, include:
Carpenteria conoidea, Alveolina sp., and Lithothamnium ramosissimum. —

Referring to the Eocene assemblage, it may again be pointed out
that the association of Alveolina and cf. Pentellina saxorum resembles
the fossiliferous contents of the ‘‘Clibs” and ‘‘Mixen” rocks of
England as well as the Miliolitic limestone of Paris, which belong to
the Lutetian or Middle Eocene group of the Tertiaries; hence, it is
suggested that a nearly similar age may be determined for the New
Guinea limestones in question.

On account of the absence of Lepidocyclina among the Miocene
organisms, it is somewhat difficult to estimate their true geological
position in that great formation. The limestones of Papua (British
New Guinea) and Mt. Carstensz (Dutch New Guinea), described
respectively by Mr. Chapman and the present writer, have yielded
various forms of Lepidocyclines, which, studied on the basis of
researches propounded by Professor H. Douvillé! in connexion with
similar fossils from some Tertiary limestones of Borneo and the
Philippine Islands, prove them to be of Aquitanian or older Miocene
age. In all probability the fossils now described belong to the same
stage of the Miocene, although the Nullipore Lithothamnium ramo-
sussimum, it should be remembered, is particularly abundant in the
‘‘ Leithakalk ’? of Europe (Vienna Basin), which is included in the
Tortonian or youngest marine stage of the Miocene system.

EXPLANATION OF PLATES VIII AND IX.

PLATE VIII.
ALVEOLINA WICHMANNI, Rutten.

Fic. la. Longitudinal section of interior. x 10.

.) 2a. oe) ”) Te) x 20.

,, 3, 4a. Internal longitudinal sections showing more regularly disposed
layers than are represented in Figs. laand 2a. x 10.

,, 5. Longitudinal view of a weathered specimen showing the margins of
successive layers and external transverse striations. X 10.

,, 6. Transverse section of specimen preserved on the polished surface
of the pebble, in which the more or less equidistant apertures
represent the longitudinal channels that perforate the organism.

x PDS
1 ‘Tes Foraminiféres dans le Tertiaire de Borneo’’: Bull. Soc. Géol.
France, ser. IV, vol. v, p. 454, 1905. ‘‘ Les Foraminiféres dans le Tertiaire des

Philippines’’: Philippine Journ. Sci., vol. vi, No. 2, pp. 53-80, pls. A-D, 1911.

212 Dr. FE. A. Newell Arber—Coal-measure Calamites.

Cf. PENTELLINA SAXORUM (Orbigny).

Fie. 1b. Internal section. x 10.

99 2b. oe) oe) x 20.

eos AA ae x 10.
The specimens figured on this Plate are from No. 1 pebble.

Puate IX.

LACAZINA WICHMANNI, Schlumberger.
Fic. 1. Longitudinal section. x 12.
,», 2. Transverse “8 6 1D
,, 3d. Longitudinal section of a compressed example. «x 10.
Cf. PENTELLINA SAXORUM (Orbigny).
,, 380. Internal sections. x 10.
ORTHOPHRAGMINA sp.
,, 4. Horizontal section of a fragmentary disc showing the internal
characteristic rectangular chamberlets and annulations of growth.
x 8.
Specimens represented by Figs. 1-4 are from No. 1 pebble.
CARPENTERIA CONOIDEA, Rutten.
,, 50. Longitudinal section of interior exhibiting the early conoidal growth,
a widened base, and chambers of crescentic form. From No. 12
pebble. x 10.
ALVEOLINA cf. MELO (Fichtel & Moll).
,, 6a. Longitudinal view of interior. x 10.
LITHOTHAMNIUM RAMOSISSIMUM (Reuss).

,, 6b. Parts of branches seen in longitudinal section. x 10.
» 7. The same, more highly magnified, displaying the rectangular cell
structure of the tissue. x 25.

Specimens represented by Figs. 6a—-7 are from No. 2 pebble.

II1I.—A Nore on Susmepuntary Casts or CoalL-MEASURE CALAMITES.
By EH. A. NEWELL ARBER, M.A., Sc.D., F.G.S.

fF\HE pith-casts of Calamites are common Coal-measure fossils,

sometimes of use in helping to fix the horizon of certain coals.
They are, however, notoriously difficult taxonomically, and in
several cases there is difference of opinion among authorities both
as to the essential characters of a particular type of pith-cast,
and also as to what is the most nearly correct name to apply to it.
Immense space is still taken up by arguments as to what, exactly,
some ancient and often manifestly rough drawing, supposed to
represent a type, really depicts—with a view to maintaining a strict
priority as regards nomenclature. If the original specimen is now
lost, as is not infrequently the case, the guessing still continues.
Some workers are not content to start their synonymies chronologically
with the next oldest figure, the original of which still survives and
the nature of which is agreed to on all hands.

But apart from such cases, there are not a few specific names in
vogue in regard to Calamite pith-casts, and also some other genera,
which are purely indefinable. ‘They are applied to certain fossils
because there exists some, usually ancient, figure which they some-
what resemble, but if we are asked to define these species in relation

Grou. Maa., 1918. PrAtE DX:

P. Dollman, photo. R. B. Newton, direvit.

TERTIARY FORAMINIFERA AND NULLIPORE, NEW GUINEA.

Dr. E. A. Newell Arber—Coal-measure Calamites. 213

to other types of Calamite pith-casts we have to confess our inability
to do so in strict terms.

There are a certain set of Calamite form-species which have given
me much trouble in this respect, but until recently I have not
understood why. Itis a common observation that such specimens as
I refer to here more particularly, never show the prints of the
infranodal canals below the nodes. These scars in my experience
offer one of the best, if not the most satisfactory, means we have of
discriminating between form-species among pith-casts, considered, of
course, in conjunction with other morphological features. I have,
however, now realized that these specimens are not, strictly speaking,
pith-casts at all. They represent incrustations of surfaces which
lay external to the pith, and I propose to distinguish them as
submedullary casts. In such cases the tissues appear to have under-
gone more or less considerable decay before the cast was formed, no
doubt to an extent which varied greatly in different cases. The
result has been that a cast has been formed of the medullary rays and
bundles at a level which lay external to the true pith-cavity and the
openings of the infranodal canals into that region.

I first realized this fact from a study of a slightly tangential
section! of the wood of a petrified stem of a Calamite, passing through
anode, in my friend Dr. Scott’s collection. Part of this section is
figured by Dr. Scott? in his Studies in Fossil Botany, so I need
only refer to it briefly here. At this level the so-called ‘‘ infranodal
canals’’ consist of solid masses of tissue, which would leave no print,
on the cast. It is only the somewhat expanded terminations of the
canals projecting into the pith-cavity which gives rise to the well-
known scars.

This section of Dr. Scott’s appears to me to throw a flood of
light on such frequently quoted and figured species as Calamites
canneformis, Schlotheim, 1820; C. pachyderma, Brongn., 1828;
C. approximatus, Brongn., 1828 (non Schlotheim); C. varvans, Stern-
berg, 1838; C. Schiitzer, Stur, 1881; and C. Schatzslarensis, Stur,
1887.

These specimens are often characterized by the coarseness of the
ribbing of the internodes. There are, for instance, in the Sedgwick
Museum, Cambridge,? several examples of large Calamite casts
from the Dogtooth Rake Ironstone, Chesterfield, with ribs 5-6 mm.
broad, without any trace of infranodal canals. ‘These appear to
correspond very closely to the C. pachyderma of Brongniart, and they
are clearly submedullary in origin. CC. Schatzlarensis of Stur
appears to be a name founded on several different types of pith- cast,
and the same is true of that author’s C. Schiitzer.

C. varians, Sternb., is also indefinable, and nothing is gained
by transferring C. approximatus, Brongn. (non Schlotheim) to Stur’s
species .C. Waldenburgensis (as has recently been suggested by Kidston)
or to an entirely new species, C. Schiitzerformis, forma Waldenburgensis,

1 No. 897.
2 Qnd ed. (1908), p. 27, fig. 8; see also pp. 47-8.
> Nos. 439-41, 478.

214 H.L. Hawkins—The A. quadratus Zone near Inkpen.

as recently adopted by Kidston and Jongmans.' All of these sub-
medullary types I now regard as, strictly speaking, indeterminable
specifically. If any one of them has any claim to be recognized,
despite the absence of infranodal scars, it is C. approximatus, Brongn.

1V.—Note on tHe Occurrence oF THE Zonrn OF A. QUADRATUS
(Sus-zone oF OrrasTER PILULA) NEAR INKPEN, BERKS.

By HERBERT L. HAWKINS, M.Sc., F.G.S8., Lecturer in Geology, University
College, Reading.

LONG the narrow belt of Upper Chalk that forms the northern
margin of the Vale of Ham (or Shalbourne), a sunken and
picturesque lane passes from the village of Inkpen in a direct line to
Shalbourne. At a distance of about a quarter of a mile west of the
cross-roads in the village (and about the same north-west of the
church), the 500 ft. contour crosses thisrcad. On the new series Survey
map (Sheet 267) a quarry is marked on the northern side of the road
near this point, and a northerly dip of 25° isrecorded. The quarry is
now almost completely grassed over, but about 100 yards to the east
of it (practically on the line of the shaft of the arrow on the map)
there is an open road-cutting, giving access to the Chalk, on both
sides of the road. .

The Chalk is much crushed, and full of small dislocations, but the
northerly dip is still quite clear. A few scattered flints occur in it,
but no continuous layers. Fossils are exceedingly scarce—indeed,
I have paid several visits to the exposure and hitherto failed to find
anything zonally distinctive. All organic remains are either already
in fragments, or collapse at any attempt to extract them.

A recent visit fo this unpromising section has, however, yielded
evidence of considerable interest. In a block of the Chalk that had,
for some local reason, escaped the worst degree of compression, three
fossils oceurred, which, though fragmentary and friable, are unmis-
takable. Thy are Offaster pilula (a small form, just like those from
Kantbury, 23 miles to the north-east); a very small, pyramidal, flat-

based Hehinocorys, whose proportions, so far as they can be determined,
are exactly those of forms from the O. pilu/asub-zone; anda primary
interradial of Stawranderaster bulbiferus, which is fully as large as
the Offaster. Spencer has shown that this species attainsits maximum
size in the sub-zone of O. pilula. Such an assemblage admits of but.
one interpretation. ‘The sub-zone of O. piluda is here present. The
fossils came from the section on the south side of the road, and,
though absolutely no traces of fossils have as yet appeared on the
northern side, there can be no doubt that the whole cutting is made
in this sub-zone.

According to the geological map, the section occurs about midway
between the Chalk Rock and the Tertiary border, so that, unless
a strike-fault occurs to the north of the road (which is quite possible),
there must be a very considerable thickness of the guadratus-zone
developed.

1 Kidston & Jongmans, Mededeel. Rijksopspor. Delfstoff, No. 7, vol. i, pt. i,
p. 101, 1915-17.

Dr. Harold Jeffreys—Causes of Mowntarn-Building. 215

Treacher and White (Proc. Geol. Assoc., xix, p. 385, 1906) identified
the Uintacrinus sub-zone south-west of Kirby House (to the east of
our section), and again at Prosperous Farm (about the same distance
to the west). In both of these instances the exposures were, if
anything, nearer to the Tertiary boundary than the roadside section.
Thus it seems probable that the outcrop of guadratus-chalk here is
of the nature of an outlier, precisely similar to the one that the
above-named authors record at Laylands Green, Kintbury. ;

There are now three patches of this zone known to occur at the
western end of the London Basin, namely, Boxford, Kintbury, and
Inkpen. It can hardly be an accident that all three occur in an
almost perfectly straight line, which has a north-east to south-west
trend. It is true that the Boxford outlier is associated with peculiar
lithological conditions and great attenuation of the zones, but in the

-case of the two more southerly outcrops there is no such peculiarity.
On the present evidence it seems reasonable to postulate the existence
of a pre-Tertiary syncline along this line, with, perhaps, a parallel
complementary anticline on the eastern side which is. responsible for
the Hampstead Marshall inlier.

V.—Tse Causes or Mounrarn-BoiLpinG.
By HAROLD JEFFREYS, M.A., D.Sc.

N article by Mr. R. M. Deeley in the Grorocican Magazine for
A March, pp. 111-120, is mainly devoted to an attempt to find
a cause of mountain-building more potent than the compression due to
cooling, of which he says that ‘‘many physicists . . . are quite
satisfied that it is not capable of accounting for the amount of
compression required’’. ‘he only physical argument he quotes in
support of this statement is that of Osmond Fisher, which he may
therefore be presumed to consider the most conclusive; yet it is
certain that no physicist would now admit that Fisher’s reasoning
has any validity. It rests entirely on Kelvin’s theory of the cooling
-of the earth, which has had to be completely revised on account of
the discovery of the extensive distribution of radio-active matter in’
the earth’s crust. ‘The time available has been found to be about
twenty times greater than on Kelvin’s theory, and the cooling has
therefore had time to extend to a much greater depth and to produce
accordingly a very much greater compression. Our present knowledge
indicates that the compression has been enough to shorten the
circumference of the earth by from 133 to 227 kilometres, according
to the precise distribution of radio-active matter assumed. The
level of no strain is at the same time found to be at a depth of about
80 kilometres, so that the crust-movements due to compression would
extend to a considerable depth.

Mr. Deeley next states that the compression required to make the
Alps would be 1,050 kilometres, and deduces, apparently by a simple
division by 7, that the diameter must have decreased by about
334 kilometres, which he says is greater than can possibly be

216 Dr. Harold Jeffreys—Causes of Mowntain-Building.

allowed. Now it is obvious that such a contraction, if it occurred, —
would shorten every diameter of the earth by this amount, and
-eould therefore raise a mountain chain as high, as broad, and as
complicated as the Alps, and extending most of the way round the
earth, whereas the estimate in question refers only to a chain some
1,000 kilometres in length. This simple method of evaluating
the contraction needed to produce a single range is evidently
unsatisfactory ; what we really need to determine is the reduction,
not in breadth, but in area, if the aggregate contraction needed to
raise all the mountains of the earth is to be found. Taking the
Rockies and the Coast Range in California as standards, according to
the breadth of the particular range considered, and assuming the
lateral compression to be proportional to the mean height above the
surroundings (which would be exactly true if the contortion in all
ranges was geometrically similar and on a scale proportional to the
height), I have indicated elsewhere that all the known mountain
ranges could probably be produced by a contraction in circumference
of some 70 km., only about half of that shown to be available.
This will, of course, have to be reviséd continually as direct geological
information about the larger ranges, especially those in Asia, becomes
available; it will further have to be increased to allow for suboceanic
mountains and old ranges now almost denuded away. At the same
time the estimate of the compression that could be produced by
cooling may need to be increased, as the coefficient of expansion
may increase more rapidly near the melting-point than I assumed ;
in any case the available compression and that needed to account
for mountain-building are of the same order of magnitude, and
a categorical statement that the theory is inadequate is clearly
unjustified.

The theory of compression is complicated by the effects of
denudation. Whena mass of radio-active matter is removed from the
surface of a continent, matter at a considerable depth is enabled to
cool more rapidly in comparison with the average over the whole
earth. In consequence it tends to contract more, and thereby
increases the curvature of the outside, just as a bow becomes more
curved when the string is tightened; the effect of this would be to
raise the continents considerably. Similarly, the ocean beds would
be depressed on account of the radio-active sediments acting as
a blanket. A definite limit must of course be imposed on these
effects by the weakness of the crust; thus the elevation and lowering
could never become much greater than was necessary to give isostatic
compensation, and afterwards more mountains would be raised within
the continents and fewer on the ocean bed. :

The alternative hypothesis offered is that crust movements have
occurred owing to heavy matter sinking into lighter matter below it
and causing it to spread out horizontally. This is physically quite
possible, but it is difficult to see how the heavy matter could have
got to the top in the first place except by compression. Isostatic
readjustment, subsequent to denudation, might easily produce gentle
anticlines and synclines, but the violent contortion implied by the
structure of the great mountain ranges seems difficult to account for

Dr. Harold Jeffreys—Causes of Mowntain-Building. 217

by means of the widespread movements that one associates with
such readjustment. ‘This hypothesis, while doubtless an important
secondary agency, can therefore scarcely be regarded as giving the
primary cause of the formation of the great mountain chains.

A digression in the meanings of the terms rigidity, plasticity,
viscosity, and fluidity may not be out of place here. When a body is
exposed to a tangential or shearing stress (such a stress, for instance,
as would exist if a rectangular block of wood had one face rigidly
fixed and a tension were applied in the plane of the opposite one) it
ordinarily changes its shape to some extent. The ideal type of sub-
stance described as perfectly elastic will spring back completely and
immediately to its original shape when the stress is removed (the
complication due to inertia being ignored). In ordinary substances,
however, the recovery may be incomplete, gradual, or absent. If it
occurs at all, the substance possesses elasticity, and the coefficient of
rigidity is measured by the ratio of the stress to the reduction of strain
when the stress is released. If it is absent, so that the body retains
the shape it had just before the release, the substance is a flurd.
Thus a fluid is a substance with no elasticity. One of its properties
is that when a constant tangential stress is applied for some time it
goes on changing its shape or flowing ata constant rate ; the viscosity
is measured by the shearing stress needed to cause flow at a certain
definite rate. When the viscosity is zero, the substance yields
completely and instantly to any shearing stress, however small; such
a substance is a perfect fluid.

Substances possessing any elasticity are called solids. Imperfection
of elasticity in a solid may be shown by the recovery after stress
being partial or gradual. If it is partial, we see that the body has
undergone a permanent change of shape, called permanent set; such
a substance is called plastic. Suppose now that a certain stress /’
applied for a certain time 7’ causes a permanent set of amount s,
where s may be small. If the body is then stressed again by the
same amount and for the same time and released, it will have
acquired a further permanent set s, making 2s in all. Repeating
the process » times will give a set ns. Now a constant stress /’
would naturally be expected to produce at least as great an effect in
the same time as an intermittent one; hence a stress / applied
for a time equal to the sum of n7Z, and the times when there was no
stress would produce a permanent set not less than ns. This can be
made as great as we like by making » great enough; hence a plastic
solid can be made to change its shape as much as we like by applying
a constant stress for a long enough time. In this respect it therefore
resembles a viscous fluid.!

1 Mr. Deeley suggests that the repetition of the stress would not give the
same set each time, but a smaller one, leading to a convergent series which
could never exceed a certain small amount. This implies that when a body
has been strained beyond the limits of recovery it is stronger and more difficult
so to strain again. The contrary seems more probable, and agrees with
the phenomena of malleability and ductility, which are inconsistent with
Mr. Deeley’s hypothesis. Clay can undergo an indefinite amount of
permanent set, and if the stress needed to give it a definite increase of set

218 Dr. Harold Jeffreys—Causes of Mowntain-Building. :

On the other hand, the recovery after stress may be slow, though
after a long enough time it may become complete. This phenomenon
is the elastic after-working. It does not lead to permanent set or to
indefinite flow when a constant stress is applied, and must therefore
be distinguished from plasticity, even though the same substance
may possess both properties. There are then two distinct kinds of
imperfection of elasticity, and the question is further complicated by
the fact that both are functions of the stress and of the previous
history of the body, some substances behaving as if perfectly elastic
for small stresses and very imperfectly so for large ones. For
instance, suppose a weight laid on a flat surface of wet clay, which
may be regarded as plastic. It will proceed to sink in, the clay
acquiring permanent set, but after a time the stresses will become
too small to cause set, and the weight will cease to sink, though
appreciable shears still exist.

The distinctions between these various properties are of funda-
mental importance in all questions dealing with the behaviour of
rocks under stress. The idea of plasticity, in particular, must
always be carefully distinguished from smallness of rigidity. If two
similar pieces of quartz and copper, for instance, are exposed to the
same stress, the quartz will yield more; but when the stress is
released the quartz springs back all the way, while the copper does
so only partially. Thus copper is more plastic than quartz; on the
other hand, the change of strain caused instantaneously by the same
change of stress is less in the copper, which is therefore more rigid.
In geophysical investigations the fact that a very rigid substance
may also be a plastic one is continually coming into notice.

In geological upheavals and readjustments elastic after-working
is probably of small importance, as the times involved are much
longer than those needed for the relaxation of the strain. The
importance of plasticity on the other hand is very great, for solid
substances may easily flow to a great extent when a lapse of time
of the order of a geological period is available, without the flow
producing any noticeable effect when earthquake waves or tides are
considered, so that for these movements the earth may behave as if
perfectly elastic. Elastic after-working acts in the opposite direction,
for if a stress is varying rapidly there will never be time for the
strain appropriate to it to be produced, and consequently short
period transverse waves cannot be transmitted for any considerable
distance. It would thus produce a greater effect on earthquake
waves than on vibrations of longer period, and we may therefore
infer from their transmission that it is not appreciable in the crust
of the earth. The remarkable effects of high pressure and tempera-
ture on the elastic properties of solids indicate, however, that it
would be dangerous to deny on this ground its possible importance
in the centre of the earth. It is certain. that no great part of the
earth is fluid, for it has been shown by Love that the yielding of the

increased beyond all limit, as Mr. Deeley supposes, it would obviously be
impossible to model it by hand. Non-ductile substances break when the set
becomes great enough, and after this occurs the series will diverge rapidly
instead of converging.

Dr. Harold Jeffreys—Causes of Mowntarn Building. 219

crust would then prevent oceanic tides from reaching any noticeable
size; earthquake waves could not be transmitted through the fluid
portions; further, isostasy would be perfect, which is not the case.
Below the layer of compensation, at a depth of probably some
300 kilometres, there is a layer of weakness known as the
‘‘asthenosphere”’, where flow appears to be produced much more
easily than in the outer portions and most of the isostatic adjustment
takes place. The properties of earthquake waves nevertheless show
that it is very rigid.

The laws of elastico-viscosity and firmo-viscosity that I have used in
previous papers are precise mathematical expressions of particular
types of plasticity and elastic after-working respectively.

In the above discussion nothing has been said about the mechanism
that causes imperfection of elasticity, and the argument is independent
of this. Barrell believes that adjustment in the asthenosphere takes
place by progressive local melting or solution under shear; the
melted parts immediately flow till the shear is reduced to zero, and
thus the shears are always kept small. In crystals it may take
place by sliding on the cleavage planes; such bodies as pitch may be
deformed by molecular displacement without anything resembling
fracture ; brittle substances may be crushed to powder and then
spread out by the stress; but in any of these cases the recovery after
the stress is removed is incomplete and the general description of
plasticity applies. Hlastic after-working is to be attributed to
intermolecular friction.

Mr. Deeley discusses at much length the question whether the
liquid and solid states pass into each other continuously or discon-
tinuously. The sudden change from one to the other at a definite
temperature is a characteristic property of pure substances; the
impure aggregates with which geologists have for the most part to
deal may be expected to pass through a pasty state when heated, in
which flow becomes steadily more easily produced. The question is
not, however, a vital one; there is little liquid within the earth, and
when it does occur it is probably produced, not by heating, but by
local release of pressure. Most of the interior is probably at a
higher temperature than the melting-point of ordinary rocks at
ordinary pressures, and is only kept solid by the high pressures there
existing. A local fracture would release this and render melting
possible.

REFERENCES.
BARRELL (Joseph). Journal of Geology, vol. xxii, 1914; vol. xxiii, 1915.
Houmes (Arthur). ‘‘ Radio-activity and the Earth’s Thermal History ’’:
GEOL. MaG., February-March, 1915; June, 1916. ‘‘ Radio-activity and
the Measurement of Geological Time’’: Proc. Geol. Assoc., vol. xxvi,
1915.
JEFFREYS (Harold). ‘‘ The Compression of the Earth’s Crust in Cooling’’ :

Phil. Mag., vol. xxxii, pp. 575-91, 1916. ‘‘ The Viscosity of the Harth ”’
(Third Paper): Monthly Notices of R.A.S., vol. Ixxvii, pp. 449-56, 1917.
Love (A. E. H.). Proc. Roy. Soc., vol. lxxxiiA, pp. 73-88, 1909.

220) Reviews—Geology of Bowrnemouth.

RAV LHwWwSsS-.

Sees

J.—T'sn Grotocy or roe Counrry arounp Bournemouru. Exprana-
vion oF SHEET 329 (New Series). Memoirs Geological Survey
England and Wales. Second edition. By H.J. Ospornn-Wuure,
F.G.S. pp. vi+ 79. London, 1917. Price 2s. net.

Lee memoir, which is published as a second edition, is really

anew book. The first edition, written by Mr. Clement Reid,
was very brief, as it was intended at the time to publish a general
memoir on the Hampshire Basin. ‘This not being possible, a second
edition of the sheet memoir has been issued in which the geology of |
the district is fully described. The book is written in an interesting
manner; a chapter is devoted to each series of rocks, and is made up
of a general section followed by more detailed description of the
particular exposures. In the general sections the geological history
of the district is clearly brought out. The oldest rock in the area
covered by the map is the Upper Chalk. At the close of Cretaceous
times the district was uplifted and denuded, and the Reading Beds
rest on a surface which shows well-marked evidence of erosion.
These beds are of freshwater origin. The London Clay, which
follows them, is of the sandy type showing shallow-water conditions,
and is becoming thinner to the west. The Bagshot and Bracklesham
Beds are classified according to the old plan and not according to that
proposed by Mr. Gardner, owing to the difficulty of separating the
pipeclays and sands of Corfe and Poole from the Bournemouth fresh-
water series in the inland exposures. These show a shoaling of the
water culminating in the Bournemouth freshwater series.

Throughout Bracklesham time the water became gradually deeper,
and the Barton Clay shows true marine conditions. This was followed
by another shallowing of the water as shown by the Barton Sands,
and the highest Tertiary rocks in the area, the Lower Headon Beds, are
deltaic in character. From evidence obtained elsewhere the Oligocene
sea must have spread over this region, but the deposits have all been
removed. The only record of Miocene or Pliocene times in the
district is the slight flexuring of the strata, which must correspond to
the more violent movements observed in the Isle of Purbeck and the
Isle of Wight.

The Pleistocene deposits are well represented. Gravels are found
at many different levels, and have been divided as follows: high
plateau, 300 ft.; highest terrace, 200 ft.; Holithic terrace, 150 ft. ;
Paleolithic terrace, 100 ft.; Bransgrove terrace, 60-80 ft.; Valley
gravels on the valley floors from 30 to 40 ft. above O.D. These all
consist of subangular flints and quartz sand, and have been laid
down in running water. No organic remains have been found, but
implements of Chellean and Acheulian types have been found in the
Paleeolithic terrace. The rivers which deposited the older of these
gravels probably drained into the ‘‘Solent River”, which was
a continuation of the Frome, and whose valley was not breached by
the sea till after the deposition of the Bournemouth plateau gravel.
The character of these plateau gravels, when compared with that of
the modern alluvium, shows that the volume of water in the ancient

Reviews—Coal Flora of the Netherlands. 221

rivers must have been very much greater then than itisnow. The
Paleolithic terrace of the Avon Valley is contemporaneous with the
Goodwood raised beach, and bears the same relation to it as
the modern alluvium does to the present beaches.

The recent alluvium contains beds of peat and submerged forests
which point to a small submergence in recent times; this is also
borne out by the form of the coast in Poole and Christchurch
harbours. The district is not rich in economic deposits. A little
iron has been worked and alum manufactured from alum shales, but
the only deposits now being worked to any extent are clays in the
Reading Beds, the London Clay and the Bagshot Beds which are
used for pottery.

Mis EW

JJ.—Frora oF tHE CaRBONIFEROUS oF THE NETHERLANDS AND
Apgsacent Reatons. Vol. 1: A MonograpH oF THE CALAMITES
or Western Evrope. By Dr. R. Kipston and Dr. W. J.
Jonemans. ‘Text, Part I, 1917; Atlas of 158 plates in 4to, with
Provisional Explanation of Figures, 1915. Mededeelingen v. d.
tijksopsporing v. Delfstoffen, No.7. Gravenhage.

Y undertaking the publication of this large and exhaustive
monograph, of which only the first part lies before us as yet,
the Dutch Government has performed a signal service to Palzo-
botany. Itisin every way entitled to take rank beside the classic
memoirs of Zeiller and Renault on the fossil floras of the French
coalfields, which are likewise Government publications. Most
unfortunately, although Britain is the richest country in Europe as
regards Coal-measures, no such publications have as yet been under-
taken by our Government, and in this respect we are far behind
other nations.

The present volume relates to the genus Calamites alone.
Dr. Kadston and Dr. Jongmans, who are together responsible for it,
have had quite an exceptional experience of these fossils, and either
the one or the other has, we believe, actually studied practically every
example of these plants which has been figured by previous authors,
except in a few cases where the types appear to have been lost.
They have also refigured here many of these specimens, and thus
cleared up many points which remained uncertain when we had to
rely on the original figures, which were often imperfect or indeed
inaccurate representations of the fossils in question. Both the text
and plates are thus exceptionally authoritative. The latter consist
of 158 large quarto sheets in collotype, and there are eighty text-
figures in addition. Some of the plates are, however, identical with
those of a smaller atlas published by Jongmans and Kukuk in 1918.
The illustrations are particularly clear and well chosen.

At present the atlas covers a somewhat wider field than the text,
for owing to the War only the first part of the latter has so far
been published.

The outlook here is systematic rather than morphological. The
strength of the treatment adopted lies in the perfection of pure

222 Reviews—Radioactivity of Canadian Springs.

synonymies, and in the description of particular specimens. In this
respect the revision of the genus is exceptionally thorough. ‘The
_ 207 quarto pages are devoted to 47 species (neglecting varieties) of
Calamite stems, of which 41 are of Upper, and 6 of Lower
Carboniferous age. Nine of these are new names, and the number of
species here first recorded from Britain is a remarkable feature of
the work.

Certain names well known and in constant use are changed on
what appear to be slight grounds. Thus C. ramosus, Art., becomes
C. carinatus, Sternb.; while it is proposed to replace C. approximatus,
Brongn. (non Schloth.), by the cumbersome term C. Schiitzetformis,
K. & J., forma Waldenburgensis, K. One cannot help feeling that
but little is gained while not a little is lost by such modifications,
however defensible they may be made by an appeal to the laws of
strict priority of nomenclature.

We also find an omission of even a bare mention of all petrified
material of Calamite stems, in which the anatomical structure is
preserved, which strikes us as unfortunate in the case of a work
professing to be a monograph of a genus.

In conclusion, we hope that our authors may soon be able to
resume the publication of this valuable systematic work. If in
future parts they could give us, in addition to the purely systematic
side, a fuller morphological account on a comparative basis of the
members of each genus, our indebtedness to them would be still
further increased.

KE. A. N. A,

I11.—Tue Raproacriviry or somE Canapran Minerat Sprines. By
J. Sarrerry and R. 'T. Exworrny. Canada, Dept. of Mines,
Bull. No. 16, 1917.

fF\HE discovery of the radioactivity of mineral waters—in the case,
for example, of the springs of Bath—confirmed the belief, long
held, that the specific virtues of many spring waters were due to
some factor other than the dissolved salts they were known to
contain. ‘The therapeutic value of radioactive waters lies in the
increased activity of all the processes of nutrition and metabolism
which they bring about, in the stimulated growth of red blood-cells,
and in the elimination of toxins. Radioactive waters (or gases
escaping from such waters) have thus a high economic value, and the
Canadian Department of Mines has therefore caused to be carried out
a systematic examination of a large number of springs in Ontario and
Quebec and of a group of hot springs at Banff, Alberta. The results —
are contained in this memoir, together with a general account of
radioactivity, its measurement, and its medicinal value.

None of the Canadian springs contain as much. radium as those of
Bath. The amount found by Sir William Ramsay in the Bath
Springs was 1388-7 x 10-12 grams per litre, whereas the highest
amount found in Canada is 46 in the same units. ‘Two other springs
have 25 and 23-5 units respectively, while the others average less than
3 units (the value for sea-water is 1 unit). These figures refer to

Reviews—Professor Daly on Metamorphism. 223

waters that are permanently radioactive, since they contain radium
salts in solution. In addition to this, however, there is a temporary
radioactivity, due to the presence in solution of the short-lived gas
radium-emanation picked up from the formations through which the
water has passed. In this respect the Alberta springs are by far the
most valuable, though the actual figures still fall below those for
Bath and Buxton. ‘The report is illustrated with a map showing the
situation of the springs investigated and with twenty-one photographs
of the springs themselves.
AntHur Homes.

IV.—MeramorPHism anp its PHases. By R. A. Daty. Bull.
Geol. Soc. Am., vol. xxviii, pp. 375-418, 1917.

ROFESSOR DALY has written a paper on the use and meaning
of the term metamorphism, and on the classification of the
various processes which give rise to metamorphic rocks, for which all
students of geology may well be grateful. The definition advocated
by the author is as follows: Metamorphism is the sum of the processes
which, working below the shell of weathering, cause the recrystallization
of the original crystalline materials in rocks (with or without chemical
reactions) or the crystallization of original amorphous materials in rocks,
the change in each case not being accompanied by a general melting of the
rock or by general simultaneous solution of its constituents.

All weathering processes are thus cut out, for their inclusion (an
attempt at which has been made by Van Hise and more recently by
Leith and Mead) leads to a gigantic subject of unmanageable
proportions, and one for which the term metamorphism ceases to have
its restricted, and therefore most useful, traditional significance.
Volatilization is also excluded, examples of this type of transformation
being the change from mud to shale, or lignite to coal, and coal to
anthracite. Daly’s definition, however, does not clearly distinguish
between alteration processes of exogenetic origin and those of
endogenetic origin, for some cases of cementation, of recrystallization
of limestones by phreatic waters, and of metasomatism by descending
solutions, are clearly included as examples of metamorphism according
to Daly, although they may be indubitably the result of exogenetic
processes. Itseems tothe present writer, following the lead of Mr. T.
Crook, whose paper on the genetic classification of rocks (Ihin. May.,
vol. xvli, p. 55, 1914) is one of the most illuminating recent
contributions to petrology, that the term metamorphism should be
still further restricted so as to exclude ali alterations due to
exogenetic processes.

The classification of metamorphic processes suggested by Daly is
as follows :—

A. Recronat Mrramorpuism (not caused by eruptive bodies).
I. Sraric Mreramorpuism (organic movement not a causal
condition).
1. (Temperature low) Stato-hydral or hydro metamorphism.
2. (Temperature high) Stato-thermal or load metamorphism.

224 Reviews —Prof. Daly—Underground Volatile Agents.

II. Dynamic Meramorpuism (orogenic movement a causal

condition).

1. (Temperature low) Dynamo-hydral or slaty (?) meta-
morphism.

2. (Temperature high) Dynamo-thermal or friction meta-
morphism.

III. Dynamo-static Mertamorputsm (/oad metamorphism in
rocks lying beneath overthrust masses).
B. lLocat Meramorpuism (caused by eruptive bodies).
I. Contract Meramorpuism (magmatic influence in control).
II. Loap-Conract Mrramorenism (combination of load and
magmatic influences).

To discuss the merits of these subdivisions would demand more
space than it is permissible here to take up, and those who are
interested will find a vigorous stimulation to thought in the paper
itself. Whether or not one agrees with all of Professor Daly’s
proposals, one may at least congratulate him on an earnest and
valuable attempt to reduce a subject of extreme difficulty from
a state of comparative chaos to one of at least theoretical order and
system.

Arruur Hormss. ©

V.—Genetic CuassiricaTion oF UnpbEercRounpD VoLaTILE AGENTS.
By R. A. Daty. eon. Geol., xii, p. 487, 1917.

ee author proposes and discusses the following classification :—

A. Maemartic or Hypocens (includes volcanic and plutonic).
J. Juvenite (primitive, virgin, original-magmatic).

(a) In liquid magma.

(6) In crystallized igneous rocks and minerals, as
occlusions, solid solutions, and chemical compounds.

(c) Hxpelled, from magma or igneous rock by crystall-
zation or heat; may remain free or go into solid
solution or new chemical compounds.

II. Rusvreenr (secondary-magmatic).
(a), (6), and (c) as above.

B. Epicene or Epreuat (includes underground atmospheric and
marine water and associated gases).
I. Sereace (fresh or marine waters of infiltration).

1. Vadose (above the water-table).

2. Phreatic (below the water-table).

(a) Arrested (free, occluded, in solid solution, or in
chemical combination).

(6) Migrating, because of gravity, the earth’s general
heat, the heat of orogenic crushing, or the heat of
igneous intrusion.

II. Connare (fresh or marine waters buried with sediments
or surface volcanics).

(a) Stagnant (free, occluded, in solid solution, or in
chemical combination).

Reviews—Kalgoorlie, W. Australia. 225

(b) Expelled, by diagenetic settling, crystallization during
metamorphism, orogenic stress, the earth’s general
heat, the heat of orogenic crushing or metamorphic
changes, or the heat of igneous intrusion.

C. Mrxep Tyrss.

V1I.—Own tur Grotogy or THE ALKaLt Rocks IN THE TRANSVAAL.
By H. A. Brouwer. Journ. Geol., xxv, p. 741, 1917.

FTER giving a general summary of what is known of the igneous
complex of the Bushveld, the author deals with the special
types of alkali rocks that occur in the Pilandsberg and Leeufontein,
and west of Lydenberg. He suggests that the nepheline syenites and
allied rocks were derived from a residual magma left after the .
differentiation from the parent magma of ultra-acid rocks containing
as much as 97 per cent of SiOz. Not only was the residual magma
enriched in alkalies and alumina relative to silica, but it also
contained a concentration of fluorine and other volatile fluxes. Much
more work, however, is needed in this region before either the age of
the complex or the genetic relations of its multitude of rock types
can be accurately determined.

V1II.—Tue Gerotoaicat Features oF tHE ‘‘NortH Enp’’, Katcoortir.
By F. R. Ferprmany. Bull. Geol. Surv. Western Australia,
No. 69. pp. 152, with 43 figures and an atlas of 14 plates.
Perth, 1916.

f¥\HE area dealt with in this memoir comprises about 2} square

miles. It is composed almost entirely of old and highly altered
igneous rocks, which can be divided into two main groups,
the older and younger greenstones. ‘The older greenstones were
originally a large series of basaltic flows, and cover the greater part
of the surrounding region. Along a line of weakness striking
N.N.E.-S.S.W. in these older rocks a series of dykes, the younger
ereenstones, were intruded. ‘These show a gradation from basic to
more acid composition, and include types ranging from dolerites to
albite porphyrites, the latter being the last of the succession. At
different times during the intrusion of these dykes the district was
subjected to intense pressure in an east and west direction, which
resulted in the amphibolitization of the igneous rocks and the
production of shear zones and thrust faults. The period of most
violent pressure took place after the intrusion of the aibite
porphyrites.

Very shortly after this siliceous solutions with vapours of boron,
sulphur, and hydrocarbons, or oxides of carbon, were forced along the
shear zones, with the formation of jaspers and graphitic schists.
These were followed by the gold-bearing solutions. They formed
several different mineral deposits; quartzose and schistose lodes
along the strike of the dykes and cross quartz veins striking more
or less at right angles to the dykes. The auriferous lodes seem to be
genetically connected with the albite porphyrites, and occur most
frequently in the neighbourhood of these rocks along the major

DECADE VI.—VOL. V.—NO. V. 15

226 Reviews—Cretaceous Fawna, New Zealand.

shear zones. They are, however, found all through the younger
greenstones and even in the older greenstones. In these rocks they
~ are accompanied by bleaching of the walls of the lode, owing to the
breaking down of the ferro-magnesian minerals with the formation of
pyrites.

Both lodes and cross veins carry gold in payable quantities, and
both are worked in the mines. ‘The workings have, up till now,
been confined chiefly to the oxidized zone, and have not anywhere
been carried far below it owing to the increased difficulty and
expense of working; they are, however, now being pushed further
down.

The memoir gives a short description of the individual mines and
is illustrated by many figures and photographs, and is accompanied
by an atlas of large-scale geological maps on which all the details of
the structure are shown.

Wi We

VIII.—Tue Creraceous Faunas oF tHE Norru-Kastern Parr oF THE
Soura Istanp or New Zeatanp. By Henry Woops, M.A.,
F.R.S. New Zealand Geological Survey, Paleontological
Bulletin No. 4. pp. i-vill, 1-42, pls. i-xx, text-figs. 1 (map) and
2 (section). .
HE fossils described in this work have been collected from two

series of beds. ‘The one, occurring in the neighbourhood of the

Clarence River, south of Blenheim, yields a fauna characteristic of

the Lower Utatur Group of Southern India. This fauna, which has

been recognized also in Zululand, Madagascar, Australia, Japan,

Queen Charlotte Island, Peru, and California, is approximately

Albian in age; and it is of interest that Jnoceramus concentricus,

so characteristic of the English Albian, is found in the corresponding

New Zealand deposits. The other series of beds, occurring in the

neighbourhood of Amuri Bluff, north of Christchurch as well as around

Christchurch itself, and south of the localities for the Utattr fauna, is

of Upper Senonian age and passes upwards into the Eocene. The lower

portions of these beds produces an Upper Senonian fauna comparable
with that occurring in the Arivalir Beds of Southern India, in

Madagascar, in the Umzamba Beds of South Africa, in Japan,

Vancouver, Chile, Southern Patagonia and Graham Land.

The forms described from the lower fauna include two new species
of Zrigonia, one of ‘‘ Modiola’’, one of Lima, one of Aucellina, one of
Panopea, and a new variety of Jnoceramus concentricus. From the
higher fauna one new species of Muculana is described, one of
Malletia (Neilo), one of Barbatia, one of ‘* Arca”, one of Cucullea,
one of Pectunculus, one of Trigonia, one of Pecten ( Camptonectes), one
of Pecten (Aiquipecten), one of Lima (Limatula), two of Inoceramus,
one of Astarte (Hriphyla), one of Anthonya, one of Lucina, one of
Cultellus, two of Callista (Callistina), one of Panopea and one of
Thracia.

The figures contained in the twenty plates are collotyped from
brush-drawings by T. A. Brock, and maintain the level of excellence
that one has come to expect in his work since the publication of his

Brief Notices. 227

drawings in Mr. Woods’ Monograph on Cretaceous Lamellibranchs.
The plates, moreover, have already had a history; for the original
issue, we are told in the introduction, was lost in the wreck of
“Tongariro” off the New Zealand coast in August, 1916. They
were reprinted from the original blocks, and the Bulletin finally —
appeared in 1917.

1X.—Brizr Norices.
1. Tae Acrive Vorcanors or New Zrartanp. By KE. S. Moonr.
Journ. Geol., xxv, p. 693, 1917.

HE author describes the five active voleanoes of New Zealand
lying along the Whakatane fault, and discusses their relation to
the later volcanic history and petrographical provinces of the islands.
Mt. Tarawera and its rocks, varying from rhyolite to basalt and

including pyroclasts, are dealt with in special detail.

2. Homocitinr anp Monoctinr. By R. A. Daty. Bull. Geol.
Soci Aun: yoluxeavil-) pe 89, 1916.

IW\HE term homocline is suggested as a general name for a mass of

bedded rocks all of which dip in the same direction. The term

monocline is thereby restricted in accordance with the definition

first formulated by Sir A. Geikie.

REPORTS AND PROCHHDIN GS.

aa)
I.—Geronocicat Society or Lonpon.

March 20, 1918.—G. W. Lamplugh, F.R.S., President, in the
Chair.

The President referred with sorrow to the death, on
March 18, of Dr. George Jennings Hinde, F.R.S., who had
served the Society for many years as a Member of the
Council. The President also recorded the loss of Captain
Lewis Moysey, M.B., R.A.M.C., who was on H.M. Hospital
Ship Glenart Castle, torpedoed in the Bristol Channel on
February 26. It was stated that the Council had sent
resolutions of condolence to the relatives of both these Fellows.

The President announced that the Council had awarded the
Proceeds of the Daniel-Pidgeon Fund for the present year to James
Arthur Butterfield, M.Sc., F.G.S8., who proposes to conduct
researches in connexion with the Conglomerates and Sandstones
underlying the Carboniferous Limestone Series in the North-West of
England.

Dr. W. F. Smeeth delivered a lecture on the Geology of Southern
India, with particular reference to the Archean Rocks of the
Mysore State. With the aid of a map, prepared by the Geological
Survey of India, the Lecturer pointed out the general character of

228 Reports & Proceedings—Geological Society of London.

the geological formations of Southern India, which consist very
lar gely of a highly folded and foliated complex of Archean gneisses
and schists, followed by some considerable patches of pre-Cambrian
slates, limestones, and quartzites; with these are associated basic
lava-flows and ferruginous jaspers. The remaining formations
consist of remnants of the Gondwana Beds (Coal-measures of Permo-
Carboniferous age), a few patches of Cretaceous rocks, some Tertiary
and Pleistocene deposits, and recent sands and alluvium, all situated
along the coastal margins of the Peninsula. He contrasted the
scanty post-Archean record of Southern India, the apparent non-
submergence of the greater portion of the area, and its freedom from
great earth-movements since Archean times, with the widely
extended formations of Northern India, which .recorded oft-repeated
movements of depression and elevation, culminating in the rise of
the Himalaya in Tertiary times and accompanied by igneous activity
on a gigantic scale, as proved by the outpourings of the Deccan Trap.
In discussing the Archean complex, the Lecturer traced the.
history of the various views which have been held. Newbold (1850)
regarded the complex as formed of Protogene schists and gneisses
intruded into by granites. Bruce Foote (1880) separated the schists
(to which he gave the name ‘“‘ Dharwar System’’) from the gneisses,
and regarded them as laid down unconformably upon the gneisses
and granites which, for many years thereafter, were embraced in the
term ‘‘ Fundamental Gneissic Complex”’. He regarded the Dharwar
System as transition-rocks between the old gneisses and the older
Paleozoic rocks (Cuddapa, ete.). Holland (1898) differentiated the
Charnockites, showing that they formed a distinct petrographical
province with intrusive relations to the main members of the
gneissic complex, and in 1906 he proposed to regard the Cuddapa
System as pre-Cambrian, and separated by a great Eparcheean
Interval from the Dharwar System, which, together with the gneissic
eomplex, he classed as Archean. In 1913 Holland added a group
of post-Dharwar eruptive rocks, and produced a classification of the
pre-Cambrian rocks of India which exhibits a remarkable parallelism
with that given by Lawson (1918) for the pre-Cambrian of Canada.
The work of the Mysore Geological Survey from 1899 to 1914 had
gradually eliminated the Fundamental Gneissic Complex, and shown
that within the area of the Mysore State—representing some 29,000
square miles of the Archean complex—the oldest rocks were the
Dharwar System, which had been intruded into by at least four
successive granite-gneisses, namely: the Champion Gneiss, the
Peninsular Gneiss (forming the greater part of the area), the
Charnockites, and the Closepet Granite Series. If we compared
this succession with Holland’s 1918 classification, without assuming
any real correlation with the Canadian rocks, but viewing the
Dharwar rocks as Huronian, as suggested by Holland, then his
post-Dharwar eruptive series (Algoman) included the whole of the
gneisses of Mysore, while equivalents of the Laurentian and Ontarian
formations were wanting. On the other hand, if the Dharwar rocks
were regarded as Keewatin, then the gneisses of Mysore might
represent Laurentian and, possibly, Algoman formations, while

Reports & Proceedings—Geological Society of London. 229

representatives of the Huronian would be non-existent. Obviously,
therefore, the Mysore Archzean succession was either very incomplete
or it did not fit in with the classifications of Holland and Lawson.
It was to be remembered that Holland’s classification dealt with
a much wider area than Southern India, and the essential problem
appeared to be whether his Bundelkhand gneiss (Laurentian) and the
Bengal gneisses (Keewatin) were really older than, and unconformable
to, the Dharwar System—as represented by him—or whether they
were post-Dharwar eruptives corresponding to portions of the Mysore
gneissic complex. In favour of the latter view it was noted that
observers acquainted with both have appeared to recognize the
Bundelkhand and Bengal types of gneisses in and around Mysore,
and that all of these gneisses have, until recently, been regarded
as forming part of the great Fundamental Gneissic Complex of Anidiar

The Lecturer then described the map of Mysore, which, on a scale
of eight miles to the inch (1 : 506,880), presented a simplified
summary of the work of the Mysore Geological Survey. On
lithological grounds the Dharwar System was divided into an Upper
and a Lower Division. The former was composed largely of basic
flows and sills with their schistose representatives. Whether some
of the chloritic schists, slates, phyllites, and argillites were of
sedimentary origin was still doubtful. In the series as a whole,
chlorite predominated and hornblende was subordinate. The
presence of carbonate of lime, magnesia, and iron was a strikingly
prevalent feature. The Lower Division was composed of dark
hornblendic epidiorites and schists, which were distinguishable from
the greenstones of the Upper Division by their dark colour and
practical absence of chlorite. Many of the greenstones and schists
of the Upper Division appeared to resemble Keewatin rocks of Lake
Superior, such as the Ely Greenstone series (save that augite is
conspicuously absent in the Mysore rocks), and it had been suggested
that the dark epidiorites, which naturally crop out between the
rocks of the Upper Division and the intruding gneisses, might be
merely metamorphosed portions of the greenstones and chlorite-
schists. This might be true in some cases, but the independent
existence of the dark hornblendic rocks of the Lower Division was
supported by the fact that they do not exist in many places where
the gneisses come into contact with the greenstones; that many of
the former retain original igneous structures, which would be
unhkely to survive the chloritization and the subsequent change to
epidiorite ; and, finally, that the amphibolitization of the rocks of
the Lower Division appears to have been complete before the
intrusion of the earliest of the gneisses which, with its associated
pegmatites and quartz-veins, has developed secondary augite in the
hornblendic rocks along intrusive contacts.

The Lecturer referred briefly to the autoclastic conglomerates
which were usually associated with intrusions of the Champion
Gneiss, to the intrusive character of some of the quartzites or quartz-
schists, and to the evidence that the limestones were, partly, if not
wholly, due to metasomatic replacement of other rocks by carbonates
of lime and magnesia.

230 Reports & Proceedings—Mineralogical Socrety.

The Dharwar schists of Mysore contain a widely extended series
of banded quartz iron-ore rocks, very similar to those of the Lake
Superior district, the origin of which has been the subject of much
discussion and is still very perplexing. Some of the earlier
American geologists considered them to be directly igneous in origin,
but these views are now discredited, and replaced by an interesting
and ingenious theory of chemical precipitation from liquids associated
with subaqueous lavas. The Lecturer suggested that some of these
rocks might be pegmatitic intrusions of quartz and magnetite, and
that some might be the metamorphosed relics of igneous rocks
composed largely of highly ferruginous amphiboles (such as
cummingtonite) or other chemically allied minerals.

ole —MIneraroeicar Socrery.

March 19, 1918.—W. Barlow, F.R. St President, in the Chair.

Professor KE. S. Federov: ciGtapiieal Operations _ with four
Independent Variables.’”? Apropos of Bocke’s suggestion of the use
of multi-dimensional geometry for such operations, with special
reference to the case of the chemical constitution of tourmaline, the
author remarks that he had already put forward a similarsug ovestion,
without, however, making use of imaginary dimensions. <A system of
points is replaced by a sy stem of vectors, and in this way, since each
end of a vector has two co-ordinates, a relation between four inde-
pendent variables may be expressed graphically. Different series of
vectors of the first order give rise to vectors of the second order, and
they in their turn to vectors of the third order. Certain special
cases were discussed.

Professor R. P. D. Graham: ‘‘ Lattice-like Inclusions in Calcite,
from North Burgess, Ontario.’ he calcite, which is almost
invariably twinned about e (0112), contains numerous fine needles,
arranged parallel to the edges of the rhombohedron ¢, of a hydrous
magnesium silicate, which chemical analysis showed to correspond to
the formula 6 Mg O.6 8102.4 H,O, which is usually assigned to the
mineral spadaite. Since the needles are only slightly acted on by
cold dilute acid, they remain behind in the form of a lattice on
dissolution of the calcite. Other included minerals are pyroxene,
quartz, titanite, and pyrites. he source of the solutions which
supplied the magnesium silicate was discussed.

Dr. J. W. Evans: ‘‘On Linear Rock-Diagrams.” The different
types of linear or variation diagrams, in which the chemical con-
stituents of different rocks are represented by vertical distances,
were reviewed, and the use of modifications to indicate the probable
mineral compositions was proposed. Lach rock is represented by
two diagrams. In the first, or alumina diagram, distances repre-
senting the molecular proportions of (1) the potash, (2) the potash
and soda, and (3) the potash, soda, and lime in each rock are measured
vertically upwards in succession one above the other from the base-
line, and corresponding points for different rocks are connected by
continuous lines. At the same times distances representing (4)
the alumina, (5) the iron oxide, and (6) the magnesia are measured

Reports & Proceedings— Liverpool Geological Society. 231

on the same lines in the same manner, and are connected by
continuous lines. Not only will this diagram indicate the pro-
portions of the constituents, but also the position of the points
on line (4) relative to those on lines (2) and (8) will indicate
the probability of the occurrence of minerals dependent on
the amount of alumina. If (4) is higher than (38), andalusite,
cordierite, or mica may be expected as well as hypersthene, all the
lime being converted into anorthite. If (4) is less than (3), diopside,
augite, or the corresponding amphiboles will probably be present;
and if it is less than (2), minerals of the egirine type may be found.
In the second or silica diagrams the lowest series of points show the
amount of silica required by the bases of a rock for the formation of
leucite, nepheline, anorthite, wollastonite, and olivine, the second
series the additional silica necessary to form orthoclase and albite,
and the third series the amount required to convert the olivine into
hypersthene, while the fourth line represents the amount of silica
actually present. The position of the last relative to the others will
throw valuable light on the silicates that may be expected, though
allowance must be made for the influence of the bases on one
another. For instance, the presence of the constituents of
wollastonite will call for a higher silicification of part of the olivine
to form a monoclinic pyroxene or amphibole at the expense of the
felspars.

III.—Liverpoot GrotocicaL Socrery.

March 12, 1918.—J. C. M. Goveir, M.D., M.R.C.P., F.G.S.,
u President, in the Chair.

The following papers were read :-—

1. ‘On the Distribution and Significance of Barium Compounds in
Sedimentary Rocks, with special reference to the Trias.” By H. W.
Greenwood.

The author had collected a large amount of statistical information
as to the presence of barium compounds in the lithosphere, the
oceans, and underground waters, which revealed their widespread
occurrence, especially in Triassic sandstones in the form of barytes.
In the latter it was noted that the barytes is apparently invariably
secondary, and has found its way into the rocks by percolation and
infiltration, that it occurs in both the Keuper and Bunter divisions,
is richest at the surface, the quantity falling rapidly with the depth,
and is commonly most abundant in the highest exposures in any one
district. These facts, among others, led the author to suggest. that
the barium had been derived from superincumbent strata, most
probably Jurassic, a suggestion which, if upheld, would make the
presence of barytes a valuable index to the original distribution of
the Jurassic seas.

2. ‘‘ Notes on the Parallel Roads of Glen Roy.” ByC. B. Travis.

In this paper the author gave an extremely lucid description of
these well-known natural features, based upon personal observations
made during visits within the last few years.

232 Correspondence—C. J. Gilbert.

CORRESPONDENCE.

THE PERMIAN IN THE MIDLANDS.

Srr,—Some thirty years ago when I was working in the new Red
Rocks of the Birmingham district, I found that the Bunter
_ Conglomerate invariably rested upon a Breccia with a slight
unconformity. I pointed this out to the late Mr. Joseph Landon,
who also found the same succession at Barr Beacon. Associated
' with the Breccia were deposits of sandy grit, the formation being of
varying thickness. I also found—what was of much greater
importance—that there was a very pronounced unconformity between
them and the red clays and sandstones upon which they rested.

On April 12, 1890, I read a paper to the Vesey Club at Sutton
Coldfield giving full particulars of this formation, which had never
been separately marked on the Survey map, nor mentioned in the
Survey memoirs, although its outcrop covered a very considerable
area. At that time the red clays which cap the Carboniferous
system in this district were mapped as Permian, which accounts for
my reference to the breccia beds as a deposit between the ‘‘ Permian ”
and the Bunter pebble beds. It is now, I believe, pretty generally
recognized that these red clays belong to the Carboniferous system.
If this be so, it gives a greatly added interest to these intermediate
beds, and it comes to be a question whether they are not really the
representatives of the Permian system in this district.

I was called away from the Midlands shortly after reading my
paper, and have since been unable to follow up my investigations.
Fortunately, however, this district has been recently re-mapped by
the Geological Survey, and I had the pleasure of hearing a paper
read by Mr. Cunnington at the Vesey Club in 1914, in which he
confirmed my work and stated that he had found the beds in some
places to reach 100 feet in thickness.

I believe the Survey are proposing to extend their researches, but
my chief reason in writing this is to point out that much can be done
by local geologists in carrying out a more detailed investigation in
regard to these beds.

A few points I would suggest are :— :

(1) Through how wide an area are they found beneath the Pebble beds ?

(2) What is their thickness and constitution in different districts ?

(3) Is the breccia constant in its composition ?

(4) Are these beds the equivalent of the typical Permian breccias in other
places, and are they on the same horizon ?

(5) The upper part of the deposit in the Sutton Coldfield district is pure
breccia, the grits being beneath the breccia, and the unconformity with the
Pebble beds is slight. Is this the rule elsewhere ?

(6) Can any light be thrown upon the source of the breccia ?

And more important than all :—

(7) Do the grits contain any fossils, and what is their age ?

In this way much may be done to supplement the work of the
Survey, which is naturally of a more general character.

A splendid section, showing the junction of the Breccia and the
Bunter pebble beds can be seen at the Black Pool Quarry at Sutton
Coldfield, at the base of which at least a quarter of an acre of the

Yee z tee th ‘ Geyer tet ‘ : a ie
a 5 ol >
; _ . :
g i
r

Grou, Maa., 1918. Prats X. —

Obituary—George Jennings Hinde. 233

rolling surface of the Breccia, from which the Pebble beds have been
saqacmedl for road metalling, can be seen.
My personal belief is that the red clays are Carboniferous, and the
breccia bed Permian.
C. J.. Ginperr.
‘“ STAGHURST,’’ BERKHAMSTED.
March 21, 1918.

A NOTE ON ISOSTASY.

Str,—I am much indebted to Mr. Anderson for calling attention
to the oversight in my calculation. His re-calculation is perfectly
right. Consequently, instead of 1,100 feet as the possible thickness
of. sediment accumulated in a sea of 100 fathom depth, we have
1,872 feet; or in the improbable case of a density as low as 2-7 for
the supporting column, as much as 3,000 feet. These figures are
still far removed from those great thicknesses of shallow-water
deposit for which isostasy has been claimed as an adequate
explanation.

A. Morztery Davies.
IMPERIAL COLLEGE, S.W. 7.
April 13, 1918.

(QyS\issenosrNiSoNai4 Sa

GEORGE JENNINGS HINDE,
Pu.D. (Municu), F.R.S., F.G.S., V.P. Pat. Soc.

BORN MARCH 24, 1839. DiED MarcH 18, 1918.
i (WITH A PORTRAIT, PLATE X.)

As a worker gleans in a cornfield after the crop has been harvested,
I have endeavoured to collect some records of my friend George
Hinde, whose life’s work terminated in March last. He was
a Norwich boy, like myself, and went to the Grammar School there,
but being my junior by seven years we never met until many years
later, our paths in early life lying wide apart.

George Hinde was the third son of Ephraim Hinde and grandson
of the founder of the firm of Ephraim Hinde & Son, Paramatta
manufacturers in that city. His father lived near his Norwich
factory, but in 1847 bought a farm at Catton, where he and his
family resided. George’s mother died when he was 138 years
old, and at 16 his father sent him to learn farming in Suffolk
with a Mr. Spelman, where, being a studious lad, he spent his
leisure hours in acquiring Latin, French, algebra, physics, and
chemistry. About this time he heard a lecture by the Rev. Mr.
Blowers on ‘‘Hugh Miller”, which greatly interested him, and he
bought and read Hugh Miller’s books, and thus his mind was first
dir ected to the study ‘of geology.

When 18 years of age he commenced to farm his own land at
Bawburgh, near Costessy, Norwich. Early in 1862 he attended
a series of lectures i in Norwich by William Pengelly, F.R.S.; these
further stimulated his desire to take up geology, which inten on
became the leading ambition of his life. In the same year he paid

234 Obituary—George Jennings Hinde.

a visit to the British Museum, and from my wife’s relationship to
his family he claimed me as a ‘‘ cousin’’, and so we continued to the
end. This visit to the ‘‘Geological Department’’ seems to have acted
as a loadstone which attracted him to the Museum in later years.
He particularly mentions in his diary the impression made upon
him by our geological talk.

In the autumn of that year he gave up his farm and sailed for
Buenos Aires, and took up sheep farming; but save for a note in his
diary of a geological walking tour, he does not appear to have had
much spare time for scientific pursuits in South America. After
some years ranching in Argentina Hinde returned home, but very
soon after set out for North America, where he devoted seven years
entirely to geological research, during which time his travels
extended from Nova Scotia on the east to Nebraska on the west,
and from Lake Superior to the Gulf of Mexico.

For a time he settled in Canada, entering himself as a student in
geology under Professor H. Alleyne Nicholson, F.R.S., in Toronto
University, with whom he published his first paper in 1875, ‘‘ On
the Fossils of the Clinton, Niagara, and Guelph Formations of
Ontario” (Canadsan Journal, xiv). He also wrote papers on ‘‘ The
Glacial and Interglacial Strata of Scarboro’ Heights, Ontario” and
“On the Occurrence of Boulders of the Calciferous Formation
near Toronto”. Later on he made the interesting discovery of
‘‘Conodonts’”’ and Annelid jaws in the Cambro-Silurian of Canada
and the United States.

teturning to England in 1874, he was elected a Fellow of the
Geological Society of London.

He also pursued his search for Conodonts and Annelid jaws in the
Silurian strata of the West of England and the Sub-Carboniferous rocks
of Scotland; he found these in many localities identical with those
he had obtained in North America, which he subsequently figured
and described in the Quarterly Journal for 1879, 1880, and 1882.

This work and the renewal of his early study of the Chalk Sponges
occupied him until 1878, when he visited Sweden, Gotland, and
Denmark and travelled across Europe to Palestine.

During 1879-80 he studied. under Professor Kari von Zittel in the
University of Munich, and upon receiving the degree of ‘‘ Doctor of
Philosophy”’ he presented for his inaugural dissertation a paper on
the ‘‘ Fossil Sponge-spicules found in a flint from the Upper Chalk
at Horstead in Norfolk” (Munich, 1880).

Dr. George Hinde was married in 1881 to Edith Octavia, daughter
of James Clark, of Street, Somerset, of the Society of Friends.

In February, 1882, he was awarded the Wollaston Fund for his
researches in fossil Invertebrata of North America and the Glacial
phenomena of Canada. He was also elected a Member of Council of
the Geological Society, on which he served for nearly twenty years,
being made a Vice-President in 1893.

After the removal of the Geological Collections from the British
Museum at Bloomsbury to the new Natural History Museum in
Cromwell Road, the Trustees authorized Dr. Hinde to prepare a
Catalogue of the Fossil Sponges in the Geological Department. This

Obituary—George Jennings Hinde. 235
was completed between 1881 and 18838, and forms an important work
of reference, admirably illustrated by Miss Suft and Mrs. Herschell
(4to; pp. vill + 248, with 88 plates).

After the death of my colleague Professor John Morris, in 1885,
Dr. Hinde became an Assistant Editor of the GrotocrcaL MacaziIne,
an office he held for thirty-two years to the great advantage of this
journal, to which he also contributed numerous articles.

He joined the Palzontographical Society in 1886 and commenced
a monograph on the British Fossil Sponges, completed in 1912.
He also contributed with Professor T. Rupert Jones, F.R.S.,
- a monograph on Cretaceous Entomostraca (1889-90). Dr. Hinde
was elected on the Council in 1897, and Treasurer in 1904, an
office he held for ten years. On retiring from it he was made
a. Vice-President in succession to Sir A. Geikie (1916).

During the meeting of the International Geological Congress in
London in 1887, Dr. Hinde rendered important services on the
Committee by preparing a temporary museum in the Library of the
London University, and also by his knowledge of languages in
acting as geological guide and interpreter to the numerous dis-
tinguished foreigners present, to many of whom he was already
personally known during his extensive travels.

When the bye-laws of the Geological Society underwent revision
in 1889, the question of the admission of women as ‘‘ Fellows”’ came
up for discussion. Dr. Hinde took a very active part in its support ;
but although Sir Joseph Prestwich and many others maintained that
the time had come when, women having proved by their work their
eligibility for Fellowship, the privileges of the Society should be
extended to them, the proposal was defeated by a majority of four
out of sixty-two Fellows voting.!

Dr. Hinde spent many years in active field-work, followed by
strenuous work in the laboratory in the preparation of rock-sections
for the microscope, and then, after much study of existing literature,
came a steady flow of scientific papers, continued for nearly forty
years.

In addition to the two important monographs on Fossil Sponges
already referred to, the subjoined list shows some twenty additional
separate papers on that class of organisms.

That on the Receptaculitide (including Ischadites, Spherospongia,
Acanthoconia, and Receptaculites) from the Silurian and Devonian
strata of England, Belgium, Silesia, Bohemia, Gotland, Canada, and
the United States, is an admirable piece of patient investigation
in solving the nature of an obscure group of fossil organisms long in
dispute. Hinde proved them to belong to a genus of siliceous
Hexactinellid sponges, of which he defined their relations and figured
their structures with elaborate detail (see Q.J.G.S., 1884).

Another example of careful and laborious work is his memoir
on the Porosphera, a group of small but very abundant globular

1 The author of this memoir, when President in 1895, discussed the same
subject ; but although strongly advocated by many of the Fellows it still
remains in abeyance.

236 _ Obituary—George Jennings Hinde.

bead-like (often perforated) organisms from the Chalk, of which (aided
by Dr. Arthur Rowe) he collected no fewer than 2,900 specimens.
_ After examination of their minute structure under the microscope he
showed them to belong to a group of Lithonine Calcisponges, of
which he described and figured six species (see Journ. Roy. Micr.
Soc., 1903).

By the investigation of chert rocks of Lower Paleozoic age from
every part of the world Hinde demonstrated their geological impor-
tance and truly organic origin, built up of millions of microscopic
siliceous skeletons, often of exquisite forms, of Radiolaria. He
devoted twenty papers to their description: those from the Cherts of
the Dutch East Indies he collaborated with Dr. G. A. F. Molengraaff,
and those of Devon, Cornwall, and Somerset, with Mr. Howard Fox,
F.G.S., of Falmouth.

Of the class Annelida, the naked wandering marine worms,
without hard parts (save very minute toothed jaws and spines),
were formerly known only by their ¢racks upon the Paleozoic rocks ;
but jaws of Annelids were found by Hinde in Cambro-Silurian
formations in America, Britain, Sweden, etc., often mixed, as in-the
Ludlow ‘‘Bone-bed”, with parts of various other microscopic
organisms, such as the teeth of cartilaginous fishes, Dyzxine, etc.),
Crustacean remains, ete. He separated many of these and figured
them, and also the Annelid jaws,’ for the first time since their
discovery by Dr. Pander in Russia in 1854.?

In connexion with the Royal Society he communicated a paper
on ‘Beds of Sponge-remains in the Lower and Upper Greensand
Formation of the South of England”, published in the Phil, Trans.,
1886 (pp. 403-53). He also reported to the Royal Society’s
Committee on Coral Reefs the result of his investigation of the
organisms obtained by him from the cores extracted from the

1 The author determined seven genera of Annelids, and enumerated fifty-five
different forms.

? Professor Owen, Dr. Harley, and H. Woodward also drew attention to
them ; see ‘‘Conodonts’’, Murchison’s Siluria, 5th ed., 1872, pp. 134, 356,
542, 544.

Obituary—George Jennings Hinde. 237

borings in a coral-reef on the Funafuti Atoll (see Phil. Trans. for
1904).

ae Hinde was elected a Fellow of the Royal Society in 1896.
In the year following the Council of the Geological Society awarded
him the Lyell Medal. In presenting it the President, Dr. Henry
Hicks, referred to the large experience gained by Dr. Hinde with
Professor Nicholson in Toronto, and continued later under Professor
K. von Zittel in Munich, which had resulted in the valuable work he
had since performed that had placed him in the foremost rank of
those devoted to the study of minute structures of fossil organisms.

In 1910 the Royal Geological Society of Cornwall conferred upon
Dr. Hinde the William Bolitho Gold Medal ‘‘for his valuable
contributions to the Geology and Paleontology of Cornwall” (partly
in conjunction with Mr. Howard Fox, F.G.8., of Falmouth.

Such are the gleanings I have gathered from the scientific work of
my friend George Hinde. He was essentially a keen investigator of
Nature, an accurate observer, and a strenuous, untiring worker who
never lost interest in his researches. He was naturally of a silent
and retiring disposition— having lived much alone in his early life—
a man who formed few intimacies, but had the gift of ardent
loyalty to those he made his friends.

He spent much of his time latterly in his quiet home at Croydon,
with his books, microscope, and specimens. After some months of
ill-health, carefully tended by his devoted wife, George Hinde
passed peacefully away on March 18, 1918. He leaves a family of
three sons and two daughters.

Henry Woopwarp.

LIst OF DR. HINDE’S PAPERS AND MEMOIRS.

1877. ‘‘ The Glacial and Interglacial Strata of Scarboro’ Heights, Ontario ’’ :
Canadian Journal, xy, pp. 388-413.

‘“*The @ccurrence, near ‘Toronto, of boulders of the Calciferous
Formation ’’: ibid., p. 644.

1879. ‘‘A new genus of Favosite Coral (Syringolites huronensis), from the
Niagara Formation, Manitoulin Island’’: Grou. MAG., Dec. IH,
Vol. VI, pp. 244-6.

‘*On Conodonts from the Chazy and Cincinnati Group of the Cambro-
Silurian, ete., in Canada and the United States’’: Quart. Journ.
Geol. Soc., xxxv, pp. 351-69.

** Annelid Jaws from the Cambro-Silurian, Silurian, and Devonian
Formations im Canada ’’: ibid., pp. 370-89.

1880. ‘‘ Fossil Sponge-spicules from the Upper Chalk, found in the Interior
of a single Flint-stone, from Horstead in Norfolk ’’ (Inaugural
Dissertation) : Munich.

‘* Annelid Jaws from the Wenlock and Ludlow Formations of the West
of England’’: Quart. Journ. Geol. Soc., xxxvi, pp. 368-78.

1882. ‘‘ Annelid Remains from the Silurian Strata of the Isle of Gotland ’’:
Bih. k. Vet. Akad. Handl., Stockholm, vii.

** Notes on Fossil Calcispongia’’: Ann. Mag. Nat. Hist., x, pp. 185-205.

1883. Catalogue of the Fossil Sponges in the British Museum (Natural
History). 4to; pp. viii + 248, with 38 plates.

1884. ‘‘Structure and Affinities of the Family of the Receptaculitide ’’ :
Quart. Journ. Geol. Soc., xl, pp. 795-849.

**Some Fossil Calcisponges from the Well-boring at Richmond, Surrey’’:
ibid., pp. 778-83.

238

1885.
1886.

Obituary—George Jennings Hinde.

‘A new species of Crinoids with Articulate Spines’’?: Ann. Mag. Nat.
Hist., xv, pp. 157-73. '

‘“Beds of Sponge-remains in the Lower and Upper Greensand of the
South of England’: Phil. Trans. Roy. Soc., clxxvi, pp. 403-53.

“* Sponge-spicules from the Deposits of St. Hrth’’: Quart. Journ. Geol.

Soc., xlii, p. 214.

‘* Hystricrinus, Hinde, versus Arthroacantha, Williams; a question of
Nomenclature ’’: Ann. Mag. Nat. Hist., xvii, pp. 271-5.

‘Note on Hophyton (?) explanatum, Hicks, and on Hyalostelia fascicu-
latus, M’Coy, sp.’’: GEOL. MAG., Dee. III, Vol. III, pp. 337-40.

1886-1912. The Fossil Sponges. Paleont. Soc. Mon., pp. 264.

1887.

1888.

1889.

1890.

1891.

1892.

1893.

“On the genus Hindia, Duncan, and the name of its typical species ”’
Ann. Mag. Nat. Hist., xix, pp. 67-79.

“The Organic Origin of the Chert in the Carboniferous Limestone
Series of Ireland’’: Grou. MaG., Dec. III, Vol. IV, pp. 435-46.

““ Character of the Beds of Chert in the Carboniferous Limestone of
Yorkshire’’: Nature, xxxv, p. 582.

‘‘New Species of Uruguaya, Carter, with remarks on the Genus’’:
Ann. Mag. Nat. Hist., xx, pp. 1-12.

““Note on the Spicules described by Billings in connection with the
Structure of Archeocyathus minganensis’’: GEOL. MAG., Dec. II,
Vol. V, pp. 226-8.

‘*The Chert and Siliceous Schists of the Permo-Carboniferous Strata of
Spitzbergen ’’: ibid., pp. 241-61.

““The History and Characters of the genus Septastrea, D’Orbigny
(1849) ’?: Quart. Journ. Geol. Soc., xliv, pp. 200-27.

“Notes on Sponges from the Quebec Group at Métis and ne the
Utica Shale’’?: Canad. Rec. Sci., iii, pp. 59-68.

‘On Archeocyathus, Billings, and on other genera allied to or
associated with it, from the Cambrian Strata of North America,
etc. ’?: Quart. Journ. Geol. Soc., xlv, pp. 125-48.

‘“On some Fossil Siliceous Sponges from the Quebec Group of Little
Métis, Canada’’: ibid., Proc. p. 24.

‘On a true Leuconid Calcisponge from the Middle Lias of Northampton-
shire’? : Ann. Mag. Nat. Hist., iv, pp. 352-8.

‘* Fragments of Siliceous Rock from the Boulder Clay of the “Roode
Klif’ (Friesland)’’: Bull. Soc. Belge Géol., Bruxelles (Mém.),
pp. 254-8.

“A new genus of Siliceous Sponges from the Trenton Formation of
Ottawa’’: Canad. Rec. Sci., ili, pp. 395-8.

“Ona new genus of Siliceous Sponges from the Lower Calcareous Grit
of Yorkshire ’’: Quart. Journ. Geol. Soc., xlvi, pp. 54-61.

‘‘Radiolaria from the Lower Paleozoic Rocks of the South of
Scotland’’: Ann. Mag. Nat. Hist., vi, pp. 40-59.

“* Some Ordovician Radiolarian Chert from the Southern Uplands of
Scotland ’’: Quart. Journ. Geol. Soc., xlvi, Proc. p. 111.

‘‘Radiolarian Chert in the Ballantrae Series of the South of Scotland’’:
GEOL. MAG., Dec. III, Vol. VII, p. 144.

‘Paleontology of Western Australia.” 2. Corals and Polyzoa:
ibid., pp. 194-204.

“A new Fossil Sponge from the Utica Shale Formation at Ottawa,
Canada’’: ibid., VIII, pp. 22-4.

‘“ Microscopic Structure of the so- called Malm or Firestone Rock of
Merstham and Godstone, Surrey’’: Proc. Croydon Micr. Club,
ili, pp. 124-31, 133.

‘Discovery of Chert containing Radiolaria, ete., in the Paleozoic
Rocks’’: ibid., p. 253.

** Palg@osaccus Dawsoni, Hinde, a new genus and species of Hexacti-
nellid sponge from the Quebec Group, Little Métis, Quebec ”’ :
GEOL. MaG., Dec. III, Vol. X, pp. 56-9.

1893.

1894.
1896.

1897.

1899.

1900.

1904.

1905.
1908.
1910.
1913.
1875.

1892.

Obituary—George Jennings Hinde. 239

“* Radiolaria in the Mullion Island Chert’’: Quart. Journ. Geol. Soc.,
xlix, pp. 215-18.

‘* Radiolarian Rock from Fanny Bay, Port Darwin, Australia ’’: ibid.,
pp. 221-6.

‘* Microscopie Structure of some of the Organic Rocks from the New
Hebrides ’’: ibid., pp. 230-1.

‘On Specimens of Archeocyathine from South Australia’’: Proc.
Geol. Soe. in vol. xlix, p. 8.

‘“A new Fossil Sponge from the Eocene of the Hast Slope of the
Ural’? : Bull. Com. Géol. St. Pétersb., xii, pp. 253-7.

“ Radiolarian Chert from Angel Island, etc., California’’: Bull. Dept.
Geol. Univ. California, i, pp. 235-40.

‘Descriptions of new Fossils from the Carboniferous Limestone’? :
Quart. Journ. Geol. Soc., lii, pp. 438-51.

“* Additional Notes on the Radiolarian Rocks in the Lower Culm-
Measures of Dartmoor’’: Trans. Devon Assoc., xxix, pp. 518-23.

“*Radiolarian Chert from the Island of Billiton’’: Jaarb. Mijnw.
Nederl. Ind., xxvi, pp. 223-7.

‘* Eminent Living Geologists: Dr. G. M. Dawson’’: GkoL. Mac.,
Dec. IV, Vol. IV, pp. 193-5.

‘“‘Radiolaria in the Devonian Rocks of New South Wales’’: Quart.
Journ. Geol. Soc., lv, pp. 38-63.

““Radiolaria in Chert from Chypons Farm, Mullion, Cornwall ’’:
ibid., pp. 214-19.

Fossil Radiolaria from the Rocks of Central Borneo, obtained by
G. A. Molengraaff in the Dutch Exploring Expedition of 1893-4.
8vo; pp. 56. Leyden.

““Henry Alleyne Nicholson’’ (Obituary): Gron. Maa., Dec. IV,
Vol. VI, pp. 138-44.

‘““Gravels of Croydon and its Neighbourhood ’”’: Proc. Croydon Micr.
Club, iv, pp. 219-33.

““ Remarkable Calcisponges from the Kocene of Victoria, Australia ’’ :

~ Quart. Journ. Geol. Soc., lvi, pp. 50-65.

‘‘Hans Bruno Geinitz ’’ (Obituary): Grou. MaG., Dec. IV, Vol. VII,
pp. 143-4.

“Zone of Marsupites in the Chalk at Beddington, near Croydon,
Surrey ’’: ibid., Dec. V,, Vol. I, pp. 482-7.

“Structure and Affinities of the genus Porosphera, Steinmann”? :

Journ. Roy. Mier. Soc., pp. 1-25.

‘* The Bone-bed in the Upper Ludlow Formation ’’: Proc. Geol. Assoc.,
XVill, pp. 443-6.

“Note on Fragments of Chert from North China’’: Grou. MaG.,
Dec. V, Vol. II, pp. 255-6.

‘* Radiolaria from Triassic and other Rocks of the Dutch East Indian
Archipelago’’: Jaarb. Mijnw. Nederl. Ind., xxxvii, pp. 694-736.

‘* A new Sponge from the Chalk at Goring-on-Thames’’: Proc. Geol.
Assoc., xx, pp. 420-1.

‘* Fossil Sponge-spicules in a Rock from the Deep Lead (?) at Princess
Royal Township, Norseman District’’: Bull. Geol. Surv. Western
Australia, No. 36, pp. 7-24.

“On Solenopora garwoodi, sp. nov., from the Lower Carboniferous in
the North-West of England’’: Gnron. Maa., Dec. V, Vol. X,
pp. 289-92.

GEORGE JENNINGS HINDE & HENRY ALLEYNE NICHOLSON. ‘‘ Notes
on the Fossils of the Clinton, Niagara, and Guelph Formations
of Ontario ’’: Canad. Journ., xiv, pp. 137-44.

—— & Horack B. Woodward. ‘‘ Excursion to Faringdon and
Abingdon ’’: Proc. Geol. Assoc., xii, pp. 827-33.

— & W. Murtron Houmes. ‘On the Sponge-remains in the
Lower Tertiary Strata near Oamaru, Otago, New Zealand”’:
Journ. Linn. Soc. (Zool.), xxiv, pp. 177-262.

\

240 Miscellaneous.

1895. GEORGE JENNINGS HINDE & HOWARD Fox. ‘‘On a well-marked
Horizon of Radiolarian Rocks in the Lower Culm Measures of
Devon, Cornwall, and West Somerset’’: Quart. Journ. Geol. Soc.,”
li, pp. 609-67.

USS. === ‘* Supplementary Notes on the Radiolarian Rocks in the

Lower Culm Measures to the West of Dartmoor’’: Trans. Devon
Assoc., xxviii, pp. 774-89. ;

1897. —— “* Additional Notes on the Radiolarian Rocks in the Lower
Culm Measures to the Kast and North-East of Dartmoor ’’: ibid.,

Xxix, pp. 518-23.
—— & W. WHITAKER. ‘“‘ Excursion to Redhill and Merstham (New

Railway) ’’: Proc. Geol. Assoc., xv, pp. 113-15.

1909. —— & F. GossiiInG. ‘“‘ Fossils from the Chalk exposed in a Road-
trench near Croham Hurst, South Croydon ’’: Proc. Croydon Nat.
Hist. Soc., 1907-8, pp. 183-4.

1890. T. RUPERT JONES & GEORGE JENNINGS HINDE. A Supplementary
Monograph of the Cretaceous Hntomostraca of England and
Ireland. Paleont. Soc. Mon., pp. 70.

1898. A. H. SALTER & GEORGE JENNINGS HINDE. ‘‘ Excursion to Upper
Warlingham and Worms Heath’’: Proc. Geol. Assoc., xy,
pp. 458-9. H. W

MISCHA N HOUS.

British Museum (Naturat Huisrory).—At the end of March
Mr. Richard Hall retired after thirty-eight years of service as
preparer of fossils in the Geological Department of the British
Museum. In early life he became a highly skilled mason, and was
engaged on many and varied important works, including the Prince
Consort’s tomb at Frogmore, some parts of the House of Commons,
and buildings on the estate of the Duke of Wellington between
Grenada and Malaga in Spain. Among his close associates for a
time was the late Henry Broadhurst, afterwards M.P. Entering
the British Museum in 1880 his abilities enabled him soon to adapt
himself to the new special work, and he acquired remarkable
proficiency in the art of preparing vertebrate skeletons. Under the
direction of the late Mr. William Davies, his first great success was
the chiselling of the skeleton of Hyperodapedon gordoni from the
Triassic sandstone of Elgin, which was described by Professor
Huxley in 1887. Afterwards, especially under the direction of the
late Professor H. G. Seeley, he began to extricate the skeletons of
Pariasaurus and Cynognathus from an almost intractable matrix, and
his work on these and other reptiles from the Karoo Formation of
South Africa led to great progress in the more exact study of the
Triassic reptilian fauna. Dicynodon halli was named after him to
commemorate his services. Mr. Hall also prepared many other
important specimens which are now conspicuous in the public
galleries of the Museum, and among them may be mentioned the
skeleton of Jehthyosaurus platyodon from Stockton, Warwickshire,
Pteranodon and Portheus from the Chalk of Kansas, Dinichthys and
similar fishes from the Devonian of Ohio, and the great collection of
Mammalian bones from the Pliocene of Pikermi, Greece. He has
won the appreciation and esteem both of students and colleagues,
and retires with the best wishes of all who have been associated
with him.

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No. VI.—JUNE, 1918

ORIGIN ATL mee a =TeG 30 1918] 2B

——$<———

I.—Tae Genesis oF Tunesrek$Ques.

By R. H. Rasvatn, M.A., F.G.9924
(Continued from the May Number, p. 203.)

Parr Il: Worrram Lopes wrrHour CaAssITERITE.

S already stated in the first part of this paper, a regular
A gradation may be traced from the cassiterite-wolframite lodes
to wolframite-quartz veins without cassiterite, a type which appears
on the whole to be more common in America than elsewhere. In
many cases this difference is clearly due to a more complete
differentiation of the magma, but in other instances a purely igneous
origin is less conclusively established. In Cornwall and other
granitic areas a tin-wolfram lode can sometimes be traced con-
tinuously into a welfram lode, and this again into a pure quartz vein.
Here the pegmatitic origin of the lodes is demonstrated, and as a rule
the wolfram is accompanied by fluorite and other recognized pneu-
matolytic minerals, as well as by sulphides similar to those found in
the tin lodes. Thus the genetic connexion with the tin-bearing
types is beyond doubt. In a few instances only wolfram is found in
association with gold ores; the significance of this will be discussed
in a later section.

One of the most interesting cases of quartz-wolfram veins without
tinstone is seen in the Sierra de Cordoba in Argentina.1. Here the
veins occur in gneiss, and are actually traceable into a large granite
mass of unknown age which is intruded into the gneiss. They are
clearly pegmatitic differentiates of the granite. The wolfram occurs
in large crystals in the quartz and in nests up to half a cubic metre
in size. he chief minerals found in association with the wolfram
are mica, apatite, fluorite, molybdenite, and chalcopyrite, and in the
oxidation zone there are various oxidized copper minerals derived
‘ from the chalcopyrite. The abundance of apatite is notable and
somewhat unusual in wolfram lodes. This is an instance of
differentiation from a magma rich in volatile constituents, especially
fluorine, but apparently without tin and boron.

Somewhat similar to the foregoing are some wolfram lodes found
near Lircay in the province of Angaraes in Peru.” Two dykes or

1 Bodenbender, ‘‘ Die Wolfram-Minen der Sierra yon Cordoba in der
Argentinischen Republik’: Zeits. fiir prakt. Geol., 1894, p. 409.

2 De Habich, ‘‘ Informe sobre los Jacimientos de Tungsteno de la Provincia
de Angaraes’’: Boll. Cuerpo Ingen. de Minas del Peru, No. 11, p. 31, 1904.

DECADE VI.—VOL. V.—NO. VI. 16

942 Rk. H. Rastall—The Genesis of Tungsten Ores.

veins, some 1°5 metres thick, and mainly consisting of quartz, carry
wolframite, pyrite, and some gold. The wolframite occurs in
thickenings of the veins, something like a chain of beads. Here
there is little evidence of any kind of pneumatolytic action.

In the United States tungsten ores are very abundant in some
localities, and the total output is now the largest of any country in
the world. ‘The tungsten boom of 1916 in the Western States has
already been referred to. The chief producers are the states of
Colorado, Arizona, and Nevada, while some important deposits of
scheelite are now being largely worked in California. The most
important area of all is undoubtedly Boulder County, Colorado,
north-west of the city of Denver. The occurrences of wolfram ores
here have been exhaustively described by Messrs. Hess and
Schaller.! The ferberite area of Boulder County, of which the town
of Nederland is the centre, lieson an elevated plateau some 8,000 feet
above the sea, forming the eastern margin of the Rocky Mountain
system. The country rock consists of biotite-hornblende granite,
gneiss, and quartz-mica schist, all of pre-Cambrian age. The ferberite
occurs in a group of veins striking south-west to north-east and
accompanied by gold and silver veins of the same general trend.
The gold veins are of two types, characterized by sulphides and
tellurides respectively, and the ferberite veins are more closely
connected with the telluride type of gold vein. The only gangue
mineral of any importance is quartz; occasionally a little felspar is
found, together with chalcedony and calcite. The sulphides
actually found in the ferberite veins include only chalcopyrite,
galena, and blende, and these only in small quantity. Some
molybdenite has been recorded from one locality only. These
veins are extraordinarily rich in ferberite, which sometimes
comprises the greater part of the veins, being accompanied only by
a little quartz. It is believed by Lindgren that these deposits are
a product of comparatively recent thermal activity, and the associa-
tion with tellurides is noteworthy.

At Leadville, Colorado, wolframite and scheelite are associated
with quartz in pyrite-gold veins; the scheelite seems, as usual, to be
somewhat later than the wolframite. These veins appear to be
connected with a monzonite porphyry.”

In the Snake Range, White Pine County, Nevada, wolframite is
found with scheelite, pyrite, fluorite, and a little gold and silver in
veins connected with a granite-porphyry and cutting quartzites and
slates. Here the presence of fluorite indicates pneumatolytic
tendencies.®

In the Black Hills of Dakota tungsten ores occur in two very
different forms: the first, seen at Etta Knob and Nigger Hill, has
already been mentioned; the second type is quite unlike anything
hitherto described. According to Irving,‘ the ore shoots of this area

1 “* Colorado Ferberite and the Wolframite Series ’’?: Bull. 583, U.S. Geol.
Suryv., 1914.

2 Witch and Loughlin, Hconomic Geology, vol. xi, p. 30, 1916.

3? Weeks, Bull. 340, U.S. Geol. Surv., 1908, p. 263. ji

* Irving, Trans. Amer. Inst. Min. Eng., 1901, and Professional Paper
No. 36, U.S. Geol. Surv., 1904, p. 363.

LSS

R. H. Rastall—The Genesis of Tungsten Ores. 243

are mineralized patches in a dolomitic limestone of Cambrian age.
They form flat horizontal masses, highly siliceous in composition,
and containing pyrite, fluorite, barytes, and occasionally gypsum.
The wolframite is specially associated with the barytes. There is
also a small amount of vanadium minerals. This deposit appears to
have been formed by gradual replacement of the calcareous country
rock by highly siliceous solutions ascending from below, and the
concentration at this particular horizon may have been determined
by the presence of impervious strata above. The tungsten may be
derived from the underlying Algonkian Series, where wolframite
occurs in pegmatites with cassiterite. If this is so, this must be
regarded as a case of secondary metasomatism, but the resemblance
to the wolfram-gold ores of Colorado and Nevada must also be taken
‘into account, and the tungsten-bearing solutions may really be of
direct magmatic origin, of post-Cambrian date, and independent of
the Algonkian tin-wolfram deposits below.

A very interesting and remarkable occurrence of wolframite at
Trumbull, in Connecticut, is described by Hobbs.! An oval hill,
some 1,000 feet long and 200 feet high, is composed of coarsely
crystalline marble, with sills of epidiorite above and below. The
ore-bodies occur along the plane of contact between the lower
epidiorite sill and the marble, and are concentrated in the epidiorite
just below the contact. The ore consists of both wolframite and
scheelite intimately mixed, with a little pyrite. The marble near
the contact contains many metamorphic minerals, especially scapolite
and garnet. The contact deposit seems to have been fed by veins in
the underlying rock, which contain quartz, felspar, fluorite, and
topaz. There are also some pure quartz veins. All of these are
evidently of the usual granite-pegmatite type, and their relation to
the basic sills is not clear. It seems probable that the ore-bodies are
really due to derivation from a granitic magma and that their
association with the basic intrusions is purely fortuitous. The latter
are evidently of the normal chlorine-bearing type, as shown by the
development of scapolite in the metamorphosed lmestone. The
presence of much scheelite is easily accounted for by derivation of
lime from the calcareous rock. ‘his, then, is not a contact ‘deposit
in the ordinary sense of the word, since the metallic constituents,
and especially the tungsten, do not seem to have been derived from
the rock in which they actually occur. It seems much more likely
to be an example of granitic metamorphism which has happened to
act on a basic rock and a limestone, and has segregated some con-
stituents from each, depositing them in combination at or near their
plane of junction.

The tungsten ores of Canada have been exhaustively described by
Walker? in a special report. They do not seem, so far as yet known,
to be of much economic importance, though some of the lodes are or

1 Hobbs, Bull. 213, U.S. Geol. Surv., 1903, p.. 98; and Twenty-second
Ann. Rep. U.S. Geol. Surv., 1901, p. 7.

2 Walker, Report on the Tungsten Ores of Canada, Department of Mines,
Ottawa, 1909. Also frequent references in the Annual Reports of the same
department.

244 Rk. H. Rastall—The Genesis of Tungsten Ores.

have been worked. In the Dominion deposits of wolframite and
scheelite seem to be of almost equally common occurrence, but they
do not show many features of theoretical interest. The only point
needing to be mentioned is that in several instances wolframite has
been found in quartz veins with scarcely any other metallic minerals ;
occasionally a little pyrite or chalcopyrite is found. In Inverness
County, Cape Breton, for example, htibnerite is found in quartz veins |
with a little chalcopyrite. In York County, New Brunswick,
wolframite occurs in quartz veins with molybdenite, pyrrhotite,
arsenopyrite, and a little cassiterite; topaz and fluorite are found in
the gangue; this is evidently a transitional type. In the Kootenay
district of British Columbia wolframite is found in some quantity
along with gold in quartz veins cutting granite and various Paleozoic
rocks. Here little or no sulphide ore is to be found. In the
Cariboo district wolframite occurs in veins with galena and pyrite,
while in the Yukon it is found associated with native gold and
bismuth. All these occurrences should be considered in connexion
with the gold-tungsten ores of Colorado and Dakota; the general
question of the relations of this type will be discussed later.

In most of the wolfram mines of Queensland, as before described,
the ores are associated with large quantities of tinstone, the latter
being in most cases the more valuable of the two, but at Mount
Carbine tinstone is so small in amount as to be negligible. This
may therefore be regarded as an occurrence belonging to the present
section of the subject, although tinstone does occur in quantity in
other parts of the same district. The ores occur in pegmatite dykes
in connexion with granites intrusive into schists and slates, which
are highly metamorphosed and are often intensely silicified. The
plans of the workings show a network of interlacing veins, varying
in size up to 6 feet wide, but usually about 2 feet. The gangue is
variable in composition, sometimes it is wholly quartz, while other
veins consist chiefly of felspar; in the mixed veins quartz usually
predominates; muscovite is rare, while tourmaline and beryl also
occur in small quantity. The only other metallic mineral found is
a small quantity of molybdenite. Wolframite has been found -in
very large blocks, one weighing 6 tons, but it is more common in
bladed and acicular forms. So far as the genesis of these deposits
are concerned, it is quite evident that they were derived from
a granitic magma, like the tinstone-wolframite ores of other parts of
Northern Queensland; their occasional association with tinstone in
the immediate neighbourhood is clear proof of a common origin, and
it appears that the portion of the granitic magma which gave rise to
the pegmatitic lodes of Mount Carbine itself had undergone a more
than usually advanced degree of differentiation, so that the tin-
wolfram-bearing fraction had been almost completely separated from
the fraction carrying wolfram alone. The mechanism of this
separation is uncertain, but it may be connected with differences
in the freezing-point of compounds of tin and of tungsten respec-
tively with the volatile elements of the magma, possibly the
fluorides. From a consideration of the facts observed in other areas,
such as Cornwall, it seems probable that tungsten is more volatile

R. H. Rastall—The Genesis of Tungsten Ores. 245

than tin, or, what amounts to the same thing, has a lower freezing-
point in certain compounds. If this be so, it would naturally be
expected that tungsten minerals would tend to travel further from
their original source than tin minerals, and in some instances it
seems to be established that this is actually the case.

An unusual type of tungsten lode containing a considerable amount
of titanium minerals is found in the Eastern Alps.’ The other
associates are molybdenite, beryl, quartz, felspar, and apatite. This
is an unusual combination, since titanium minerals seem to be
decidedly rare in tin-tungsten lodes.

Wolfram sometimes occurs in lead-silver lodes, as, for example, at
Neudorf in the Harz, where it is accompanied by fluorite, but this
association seems to be decidedly uncommon.

In concluding the descriptive portion of this section attention may
be drawn to the remarkable fluorite veins of San Roque in Brazil
described by Valentin. Although not containing any tungsten ores,
nevertheless there are affinities to the tungsten type, and these may
be considered as the extreme case of this kind of differentiation.
The veins consist almost exclusively of quartz and fluorite, the
latter showing a great variety of colours. There is occasionally
a little pyrite, but no other metallic minerals. These veins appear
to be in close connexion with the intrusion of the granite of Achala,
and represent the consolidation product of the last residue of the
magma after the metallic constituents, if present, had been strained
off and erystallized at higher temperatures.

Summary or Parr II.

To sum up this part of the subject, it appears that the wolframite
deposits without tinstone include a considerable number of types of
very varying character. Some of them are clearly of direct
magmatic origin, and formed in a manner exactly similar to the
wolframite-cassiterite lodes of granite areas. That is to say, they
are produced from the granitic magma by differentiation carried
a stage further than in the case of the tin-bearing lodes, leading to
a complete separation of tin and tungsten. This process may, in
fact, be regarded as an example of fractional distillation on a large
scale. The extreme case of this kind of differentidtion is afforded
by the quartz -fluorite veins of San Roque, which are analogous to
the topaz veins of some tin-bearing areas.

But in addition to the foregoing comparatively simple case it will
be seen that this class also includes several varieties of widely
different origin; some of these may be due to peculiar forms of
differentiation, whereas others are certainly metasomatic; for
example, the replaced dolomite in the Black Hills. It is doubtful
whether any true contact deposits occur; those hitherto assigned to
this origin may be capable of explanation in some other way.
Finally, in some areas our knowledge of the geological conditions is |

' Weinschenk, ‘‘ Die Minerallagerstitten des Gross-Venediger Stockes’’
Zeits. fiir Krist., vol. xxvi, 1896. )
* Valentin, ‘‘ Uber das Flussspathvorkommen von San Roque’’: Zeits. fiir

prakt. Geol., 1896, p. 104.

246 L. M. Parsons—Dolomitization

at present too incomplete to allow any conclusions to be formed as to
the genesis of the ores.

Theoretical discussion of the facts set forth in this section will be
postponed until after the scheelite deposits have been described,
since in many instances the problems involved are very similar.

(To be continued.)

IJ].—Dotomirization:-anp THE LurIcESTERSHIRE DoLomIvEs.
By L. M. Parsons, M.Sc. (Lond.), D.1I.C., F.G.S.
(PLATE XI.)

Part 1: Evipences oF THE Prriop or DoLomrrization.

CONTENTS.

Classification of Types.
Field Evidences.
Inherent Structural Evidences.
Selective Dolomitization.
The Absence or Presence of Fossils.
Classification of Petrological Types.
The Dense Yellow Dolomites of Breedon, ete.
The Red Ferruginous Dolomites of Breedon and Breedon Cloud.
The Barren Grey and Yellow Dolomites of Ticknall and Calke.

10. Fossiliferous Dolomitic Limestones of Ticknall and Calke.

N the district north of Ashby-de-la-Zouch dolomitized Carboniferous

Limestone crops out where the Leicestershire border adjoins that
of South Derbyshire. The dolomites, which attain a thickness of
nearly 900 feet in this area, have hitherto received very little attention.
I therefore propose to give a short description of them with a view
to ascertaining how far their mode of occurrence and structure afford
additional examples of, or exceptions to, the usual conclusions adopted
‘concerning the origin of dolomite. With this object in view I propos
to give a brief resumé of the evidences generally relied upon to
explain the origin of dolomite, before proceeding to describe the
Leicestershire rocks.

CHAIR AR wD

1. CrassiFication or TypEs.

If dolomites are classified .as simply as possible according to the
period at which the dolomitization! took place, well-defined classes,
as enumerated below, may be recognized :—

( 1. Those deposited as elastie rocks derived from
Primary pre-existing dolomite.
dolomites. 2. Those chemically precipitated as dolomite, with
or without the agency of organisms.

1. Contemporaneous dolomites, or those deposited
as ordinary limestones which have been altered, soon
after deposition, by the influence of magnesian salts in

Secondary } the sea in which the rocks were originally deposited.

dolomites. 2. Subsequent dolomites deposited as _ ordinary
limestones which have been altered by the influence
of waters belonging to some period later than that
during which the rocks were originally deposited.

' Throughout this article the term doiomitization signifies the production of
dolomite, either primary or secondary.

and Leicestershire Dolomites. 24.7

With regard to this classification it must be ndéted that as some
confusion has existed concerning the significance of the term
‘‘contemporaneous”, that name is used here strictly to denote
dolomites of secondary origin.

The term ‘‘ subsequent”? has a wider significance than that of
‘‘vein” dolomitization, as certain leached dolomites and some other
dolomitized rocks of undoubted subsequent origin cannot be described
adequately as vein dolomites, since some of them do not occur in
association with veins and channels. Evidently vein dolomites
constitute a subdivision of subsequent dolomites. It is now generally
admitted that the majority of dolomites are of secondary origin, the
contemporaneous class probably being more numerous than the
subsequent, but certain cases of dolomitization appear to be explained
most satisfactorily by the theory of primary deposition. Many
chemical experiments have been performed in the endeavour to
produce dolomite at different pressures and temperatures, but with »
limited success! In spite of the comparative failure of these
experimental attempts to produce dolomite artificially, the fact that
it does occur in nature as a chemical precipitate is shown by its
occurrence in mineral veins. It is very doubtful whether any
reliable evidence can be obtained from experiments performed under
conditions which may be quite unlike the natural conditions which
existed in the seas of remote geological periods.

In determining the class to which a dolomite belongs, one must
rely upon the collective evidence afforded by :—

Field relations,

Inherent structural features,
Selective dolomitization, and

The absence or presence of fossils.

Space permits only an incomplete survey of the phenomena
connected with dolomitization, and a short discussion of the more
reliable sources of evidence is all that is attempted.

e
2. Fretp EVIDENCES.

(a) The occurrence of truly bedded dolomites associated with beds
of such deposits as gypsum or rock salt is considered to support the
view that the dolomite was primarily precipitated.’

(6) The theory of primary deposition is also supported by the
occurrence of genuine beds of dolomite alternating with beds of
limestone. In this case it is inferred that the dolomite was either
chemically precipitated,’ or laid down as a clastic deposit derived
from a source different from that of the non-dolomitic limestone.
Pseudo-interbedding, characterized by the failure of the dolomitization
to conform accurately to bedding planes, the lateral transition of
dolomite into limestone, and sometimes by a streaky development of

1 See F. W. Clarke, ‘‘ Data of Geo-chemistry’’: Bull. Geol. Sury. U.S.A.,
No. 616, p. 559, 1916.

2 See Weigelin, Newes Jahrb., Beil. Bd. xxxv, p. 628, 1913.

5 Suess, The Face of the Earth, English translation, vol. ii, p. 262, 1906.

248 L. M. Parsons—Dolomitization

dolomite in the intervening limestone, is in fayour of subsequent
dolomitization.*

(c) The presence of interbedded conglomerates containing fragments
of dolomite derived from older dolomites below would suggest that
the dolomitization of the older beds was not of subsequent origin,
and that the dolomitic material of the conglomerate was a primary
clastic deposit.”

(d) The persistence of uniform bedded dolomites over a wide area
without lateral transition into unaltered or poorly magnesian lime-
stones is considered to be one of the strongest evidences in favour of
contemporaneous dolomitization.* This conclusion receives further
support if such dolomites occur at the same stratigraphical horizons
in different areas, but the presence of dolomite at a certain horizon in _
one area and its absence at the same horizon in another area, does
not necessarily indicate dolomitization of subsequent origin. Dolomite
may have been formed in shallow water, while poorly dolomitic
or unaltered limestones were being deposited further from the
shore-line.*

(¢) Should beds of dolomite be found, when traced laterally, to
pass into unaltered or poorly magnesian limestones, the inference is
in favour of subsequent dolomitization,® provided that other more
conclusive evidence of a different origin is not forthcoming.

(f) A patchy development of dolomite and limestone due to rapid
lateral transition from one into the other is a modification of (e), and
lends support to a similar conclusion.6 A patchy development of
dolomite and iimestone on a small scale, known as pseudo-brecciation,
is discussed later.

(g) The evidence in favour of subsequent dolomitization is much
stronger when an irregular or patchy development of dolomite is
associated with faulting or jointing. In such cases it is obvious
that the fault planes and joints have probably served as channels for
percolating magnesian waters of a period subsequent to that during
which the rock was originally deposited.’ Dolomites of this class
are properly described as vein dolomites.

(A) Faulting associated with extensive and non-patchy dolomites
(d) appear to indicate that the faulting occurred after dolomitization.

While discussing field relations we may observe that great thickness
of bedded dolomite has been considered to support the view that the
dolomite was of primary origin, but since a thick mass of limestone
may be dolomitized during a long period of subsidence,® as in the
case of certain coral reefs, it is questionable whether mere thickness

' Calvin, Iowa Geol. Sury., vol. vii, p. 151, 1896.
* See Swansea (Mem. Geol. Surv.), 1907, p. 13.
: Dixon, Swansea (Mem. Geol. Surv.), 1907, p. 13.

Td ee peadlae
Hardman, Proc. Roy. Irish Acad., ser. 11, vol. ii, p. 728, 1875-7.
° F. M. Van Tuyl, ‘‘ The Origin of Dolomite’’: Iowa Geol. Surv., vol. xxv,
p. 364, 1916.

’ The Geology of the South Wales Coal Fields (Mem.Geol. Surv.), pt. ii, p-33.
8 Skeats, ‘‘ On the Dolomites of the Southern Myrol2: OpdnG 3S. volelsa,
p: 97, 1905.

and Leicestershire Dolomites. 249

can be considered to yield any reliable evidence concerning dolomitiza-
tion in general.

3. InueERENT StrrucruraL EviIpENCES.

(c) The degree of idiomorphism of dolomite crystals may afford
subsidiary evidence concerning the class to which the dolomite
may be assigned.!. In many cases where subsequent dolomitization
is amply proved by other evidences, it is found that the rhombohedra
are considerably more idiomorphic than those of most dolomites of
undoubted contemporaneous or primary origin. In the latter cases
there is a marked tendency of the crystals to interfere with one
another, the resulting structure being amore or less granular mosaic.

(7) The size of the rhombohedra is usually larger in subsequent
dolomites where the growth of crystals is less impeded than it is in
contemporaneous and primary dolomites.’

(4) As in the case of idiomorphism and size, the degree of purity
of a dolomite is suggestive, but by no means conclusive.®

Crystals of a primarily precipitated dolomite should, in general, be
less contaminated with impurities than those of a dolomite of
secondary origin, though a contemporaneous dolomite may attain
a fair degree of purity. It is, perhaps, safer to place no reliance
upon the degree of purity.

(2) The relation of iron oxides, particularly hematite, to the
dolomite rhombohedra, affords one of the most reliable evidences
concerning subsequent dolomitization.£ When hematite is included
either centrally or zonally in the rhombohedra the only possible
conclusion is that the hematite was introduced at the time when the
dolomitization took place. For instance, in a district where Trias
comes above Carboniferous dolomites having zonal inclusions of
hematite, the obvious inference is that the dolomitization was
subsequent and associated with waters percolating through the Trias
(see micro-photograph, Pl. XI, Fig. 1). On the other hand, should
the hematite be only interstitial, the inference is that dolomitization
took place before the introduction of iron oxide. Ina case where
Trias rests upon Carboniferous dolomites, the presence of only
interstitial hematite in the dolomite would indicate that the
dolomitization was certainly Pre-Triassic, perhaps contemporaneous.
Inferences similar to those made from the presence of included
hematite appear to be justified in cases where dolomitization is
intimately associated with other ores such as galena and zinc blende.?

(m) The relation of rhombohedra to chert in cherty dolomites
affords definite evidence with regard to the relative periods at which
the dolomite and chert were respectively formed.® If rhombohedra
oceur enclosed by chert, the inference is that the dolomite was
formed either before or simultaneously with the chert. On the

1 See F. M. Van Tuyl, Iowa Geol. Surv., vol. xxv, p. 390 et seq., 1916.
2 Swansea (Mem. Geol. Surv.), 1907, p. 16.

5 F. M. Van Tuyl, Iowa Geol. Surv., vol. xxv, p. 319.

+ Swansea (Mem. Geol. Sury.), 1907, pp. 15, 16.

5 Schmidt, Trans. St. Louis Acad. Sci., vol. iii, No. 2, 1875, p. 246.

6 H. H. Thomas, Ammanford (Mem. Geol. Surv.), 1907, p. 76.

250 LL. M. Parsons—Dolomitization

other hand, should chert contain no included rhombohedra, the
formation of chert must have preceded that of dolomite, though this
does not necessarily prove subsequent dolomitization, since there is
no indication of any great period of time having elapsed between the
formation of chert and that of dolomite.

4. Serxrcrive Dotomrrization.

The term ‘selective dolomitization’’ has been applied to certain
phenomena in which the formation of dolomite occurs more in certain
portions of rock, presumably the less coarsely crystalline and more
unstable parts, than in other more resistant portions. One result of
this differentiation is a rock of mottled appearance at times not unlike
a breccia. The relations between the dolomitic and non-dolomitic
portions of such rocks may afford evidence concerning the origin of
the dolomite.

(nm) Pseudo-brecciation, in which a limestone assumes a mottled
appearance on account of a patchy development of dolomite on
a small scale, can scarcely be considered to yield evidence analagous
to that of patchy dolomitization on a larger scale (f). That
a pseudo-breccia is unlikely to be due to the formation of primary
dolomite appears to be a legitimate inference, but the question as
to whether the dolomitization of any particular pseudo-breccia is
contemporaneous or subsequent must be decided by inherent evidence
other than that of mere mottling. Thus a rock of this kind in which
hematite is aaah y interstitial may be referable to contemporaneous
dolomitization.'

Any particular pseudo-breccia may sapoly evidence of its own
origin, but cannot form the basis for a definite generalization
concerning the mottling of dolomitic limestones. Each case must
be considered on its own merits.

(0) A mottled appearance in which the dolomitic material is
worm-like or fucoid suggests dolomitization facilitated by the
presence of the remains of alge or other organisms.?

Of particular interest are cases of fossiliferous dolomitic limestones
in which selective dolomitization has differentiated between the
matrix and organic structures. It frequently happens that in
dolomitic rocks. proved by general evidence to be of subsequent
origin, the matrix, whether calcite or aragonite originally, has been
lar sely converted into recrystallized calcite prior to dolomitization.?
The recrystallized matrix, presumably on account of its relatively
coarse texture, is appar ently more stable than the original calcareous
material of organic remains, consequently dolomite crystals have
developed more in fossil structures than in the recrystallized matrix.

(p) Hence it is inferred that differential dolomitization of this
kind may be an indication of subsequent alteration.. That such
an inference may not always be legitimate is evident from the
occasional occurrence of dolomite crystals enclosed by recrystallized

' For instance, see Swansea (Mem. Geol. Surv.), 1907, pp. 14, 15.

2 Peach & Horne, North-West Highlands of Scotland (Mem. Geol. Surv.),
1907, p. 366.

* Swansea (Mem. Geol. Surv.), 1907, p. 16.

and Leicestershire Dolomites. Dini

calcite, suggesting that the dolomitization may have been con-
temporaneous.

It has been shown that in certain contemporaneous dolomites,
fossil structures, including corals, have resisted dolomitization to
a greater extent than the matrix has done owing to the non-
recrystallized material of the matrix being more unstable than the
more coarsely crystalline material of organic remains.

(q) From this it may be inferred that the greater development of
dolomite in the matrix than in fossil structures, including corals, is
in favour of the theory of contemporaneous dolomitization.' But
while this may be true in many cases, it is by no means certain that
selective phenomena of this kind should always be relied upon to
furnish conclusive evidence of the period of dolomitization. In
connexion with the question of the relative stability of matrix and
fossil structures, it must be remembered that the calcareous contents
_ of dolomitic limestones may have consisted originally of any or all
of the following forms of calcium carbonate: aragonite mud, more
coarsely crystalline aragonite, calcite mud, and more coarsely
crystalline calcite. Of hose, ‘aragonite mud is certainly the most
easily converted into dolomite, and coarsely crystalline calcite is the
most stable, but whether the more coarsely crystalline aragonite of
coral tissues is more unstable than calcite mud appears to be an
open question. It is just this point which weakens evidence afforded
by selective dolomitization. In the contemporaneous alteration of
a coral limestone containing few other organic remains, the matrix
consisting mostly of aragonite mud would certainly be more easily
dolomitized than the coarser coral structures.

Most organic limestones, however, consist largely of calcitic
remains as well as coral structures, so that calcite mud must have
been present originally in the matrix, and may even have been in
excess of aragonite mud. If calcite mud is more susceptible to
alteration than coarser aragonite, in contemporaneous dolomitization
the matrix would still be dolomitized in preference to coral structures.
On the other hand, should calcite mud be more stable than coarser
aragonite, contemporaneous alteration of a mixed organic limestone
would result in the development of dolomite more in coral structures
than in the matrix. Again, there appears to be no means by which
the proportions of aragonite and calcite muds in the original matrix
may be ascertained. Considerations of this kind suggest that the
phenomena of the selective dolomitization of organic rocks can
scarcely be relied upon to supply sound evidence, particularly in
cases where such phenomena appear to contradict the evidence
afforded by field relations or other reliable features.

Selective alteration of oolitic limestones may be more reliable,
since the differentiation in such cases is between coarser calcite and
finer calcite. If dolomitization has attacked odliths in preference
to a recrystallized matrix, the alteration is probably subsequent ;
on the other hand, the development of dolomite more in a non-
recrystallized matrix than in ooliths may indicate contemporaneous
dolomitization,

? Swansea (Mem, Geol. Sury.), p. 15.

252 L. M. Parsons—Dolomitization

REFERENCE. | |e

TRIAS.
PERMIAN.

COAL MEASURES.

FUILLSTONWE CRIT.

SHALES.

CARB. Ls.

CHARN/I AN.

TICKNALL &

@ SREEDON

E oi
§ BREEDON CLOUD’

® BARROW HILL
®0OSGATHORPE

SCALE in NILES.

le ae i position of the Tees Dee ee a with those
of the Carboniferous Limestone of Derbyshire and of the Charnwood
Pre-Cambrian.

o. Tur Axpsence or Presencr or Fossrtts 1n DOoLoMITEs.

It is doubtful whether any reliable evidence of the period of
dolomitization can be obtained from the absence of or ganic remains.
A primarily precipitated dolomite would probably be deposited under
conditions unfavourable to life, but it is also conceivable that either
contemporaneous or subsequent dolomitization could be so complete
as to obliterate all traces of organic structures that may have been

and Leicestershire Dolomites. 253
present originally. In other words, the final stage of secondary
dolomitization might produce the complete alteration of a rock
which may have exhibited selective phenomena in its early stages of
alteration.

(r) The presence of fossils ina dolomite is a little more significant,
particularly if they are at all numerous. The argument is then
against the theory of primary precipitation. In a rock showing no
selective features the condition of fossil structures as casts or as
replacements in dolomite, appears to yield very little evidence of
contemporaneous or subsequent alteration since both casts and
replacements of the same class of organisms may occur in the same
bed of dolomite.

The perfect replacement by dolomite of coral structures is certainly
suggestive of contemporaneous alteration, since such replacements have
been found to occur in modern reefs before calcitic recrystallization
of coral tissues took place."

Part Il: Tae LercestersHire DoLomIites.

A series of faulted inliers of Carboniferous dolomites extends in
a north-westerly direction from the edge of Charnwood, commencing
with small patches of dolomite at the village of Osgathorpe,
and ending to the north in the mass forming Breedon Hill,
a landmark for many miles. Between these limits of the series
are situated the dolomite hill known as Breedon Cloud and the
much smaller though petrologically similar inlier called Barrow
Hill. In each of these cases the Carboniferous Limestone is
surrounded by unconformable Keuper. A few miles to the west of
Breedon there are small valley inliers of Lower Carboniferous rocks
containing bedded dolomites and dolomitic limestones at Ticknall and
Calke Park. At these localities the Lower Carboniferous is succeeded
conformably by Millstone Grit, which is overstepped at one or two
places by Trias.

6. CLASSIFICATION oF PETROLOGICAL TYPES.

Disregarding details of stratigraphy and paleontology which I have
described in another paper,’ and considering the formations purely
from a petrological point of view without assuming the mode of
origin of the dolomite, we may distinguish in the area different
types of dolomitic rocks as follows :—

Dense yellow dolomites of Breedon and Breedon
Dolomites proper, containing | Cloud (1).°

a proportion of magnesium Red ferruginous dolomites of Breedon and

carbonate approaching 40% Breedon Cloud (2).

Barren grey and yellow dolomites of Ticknall (4).
Dolomitic limestones Perth

taining a relatively small] Fossiliferous dolomitic limestones of Ticknall

percentage of waaanane| and Calke (3).

carbonate

1 See Cullis, ‘‘ The Atoll of Funafuti’’: Report of Coral Reef Committee,
Royal Society, 1904, section xiv, p. 407.

2 See Abstracts of the Proc. Geol. Soc. of London, No. 1004, March 14,
lsat gy

> The numbers in parentheses indicate relative stratigraphical positions in
ascending order.

254 LM. Pareone= “Delonitieanion

In this table the types predominating in the district are placed
higher in the list.

7. Tur Densz YetLow Dotomites oF BreEepon, BreEepon Croup, Ere.

The bulk of the dolomites of the two Breedons, Barrow Hill, and
Osgathorpe consists of dense yellow material having a specific gravity
and chemical composition approaching those of a pure dolomite.
The proportion of Magnesium Carbonate varies slightly in different
beds, but averages nearly 40 per cent, while iron compounds and
insoluble residues are present in small amounts.

The field relations of these rocks are studied best at Breedon-on-
the-Hill, where quarries are being worked in a direction at right
angles to the strike. At this locality more than 800 feet of fairly
thick-bedded dolomites succeed one another without any marked
variation in petrological characters and without any apparent com-
plications due to faulting. Though the chemical composition and
texture of the material forming one stratum may be slightly different
from that of another, the inherent characters of any particular bed
appear to be uniform. The dolomitization is in no case patchy (/).}
Laterally the beds do not pass into unaltered or poorly dolomitic
limestones (d), though this fact would have greater significance if the
Carboniferous Limestone of the area had a larger outcrop. The
absence of faulting at Breedon suggests the improbability of
subsequent vein dolomitization associated with dislocation (g). At
Breedon Cloud strike faulting does occur, but is there associated
with non-patchy yellow dolomites which do not pass laterally into
unaltered limestone (A).

Conglomerates and pseudo-breccias are not present. Microscopic
sections of the yellow dolomite of Breedon, Breedon Cloud, and
Barrow Hill show a fine-grained crystalline structure composed
mainly of small grains more or less allotriomorphic, though some
rhombohedral outlines may be seen (jy andz). ‘The degree of purity
is not high since minute dusky inclusions of insoluble matter are
very numerous (/). There are no zonal or central inclusions of
hematite, and what little iron oxide does occur, mainly limonite, is
interstitial (7). Chert is absent from the material exposed in the
workings of Breedon-on-the-Hill, though it occurs in the yellow
dolomites of a higher horizon at Breedon Cloud. Sections do not
show any dolomite rhombohedra in the chert (m). Fossils are not
numerous at Breedon, Barrow Hill, and Osgathorpe; those that do
occur at these localities consist chiefly of dolomite casts of Brachiopoda
and a few corals. At Breedon Cloud, however, higher beds are
exposed and fossils are more plentiful. Corals are preserved as
dolomite replacements and as casts (7). Syringopora is usually
found as casts, but Michelinia, Campophyllum, and other genera exhibit
septa, tabule, and other structures beautifully preserved in minutely
erystalline dolomite. Goniatites ( Glyphioceras) also occur as dolomite
replacements, but Brachiopoda are present as casts.

The conclusion to be drawn from the collective evidence concerning

' Italic letters in parentheses refer to corresponding evidences mentioned in
the earlier part of the article.

and Leicestershire Dolomites. 255

the yellow dolomite of Breedon, ete., is undoubtedly in favour of
contemporaneous dolomitization.

8. Tue Rep Ferruermous Dotomitrs oF BREEDON AND
Breepon Curovp.

The uppermost portion of the Carboniferous Limestone sequence
seen at Breedon and Breedon Cloud is composed of several feet otf
thinly bedded red dolomites quite distinct from the more massive
yellow dolomites below. ‘These red dolomites cannot be seen to pass
laterally into unaltered limestone (d), but it must be remembered
that the outcrop is not very extensive. The rock is patchy in the
sense that the proportion of magnesium carbonate varies in any
particular stratum, but there are no external appearances analogous
to those of pseudo-brecciation (n). Faulting occurs at Breedon
Cloud, though I infer that dislocation has not been a factor of the
dolomitization for the following reasons: (1) no faulting occurs at
Breedon-on-the-Hill where these red dolomites are otherwise
precisely similar to the corresponding rocks at Breedon Cloud, (2)
the faulting at Breedon Cloud is also associated with the yellow
dolomites yielding very strong evidence of contemporaneous
dolomitization (fh).

Microscopic sections exhibit a structure ‘characterized by idio-
morphic, fairly large, and very impure rhombohedra (7, 7, and 4).
Well-marked central and zonal inclusions of hematite occur in the
erystals of dolomite forming these beds (/) (micro-photo, Pl. XI,
Fig. 1). The outer zones of the crystals are free from hematite,
but contain other inclusions similar to those in the rhombohedra of
the yellow dolomites. A few streaks and patches of recrystallized
calcite are present, and it is probable that this recrystallization
took place prior to dolomitization.

It has yet to be proved whether coarsely erystalline calcite, either
original or recrystallized, is under any particular conditions immune
from alteration to dolomite. In connexion with this question, the
condition of crinoid stems and ossicles in these red dolomites is
interesting. Micro-photo, Pl. XI, Fig. 2, taken from a specimen
of the Breedon rock, shows a crinoid ossicle invaded by hematite-
bearing dolomite near the central passage and around the external °
margin, which is badly corroded by the alteration.

Other organic structures are obscure. That other fossils were
present in these rocks originally, is shown by the occasional
occurrence of coral and Brachiopod casts. It appears that we have
here an instance of undoubted subsequent dolomitization in whick
both the matrix and organic structures, with the exception of
encrinites, have been completely altered. Even crinoid remains, a
most stable form of calcite, have been altered to some extent. With
regard to the matrix, there is no way of ascertaining its original
condition. It may have been calcite or aragonite, or a mixture of
the two; or it may have been calcite recrystallized prior to
dolomitization. Evidently this rock affords an illustration of the
fact that conclusions are not easily made from phenomena connected
with selective dolomitization.

256 L. M. Parsons—Dolomitization

The evidences concerning the origin of the Breedon and Breedon
Cloud red dolomites indicate quite definitely that the dolomitization
“was subsequent and associated with waters percolating through the
Trias, which formation rests upon the upturned edges of the red
dolomites at these localities. It seems fairly evident that this
subsequent dolomitization has attacked previously unaltered lime-
stones (2)' lying between apparently contemporaneous dolomites
stratigraphically lower (1) at the Breedons and higher (4) at
Ticknall.

9. Tur Barren Grey anp YeEttow Dotomires or TicknaLL AND
CALKE.

About ten feet of bedded dolomites, yellow below but grey above,
occur at the very top of the Carboniferous Limestone at Ticknall and
Calke. They are succeeded by dark shales which pass up conformably
into Millstone Grit. The chemical composition of these dolomites is
similar to that of certain rocks described by Professor Skeats as
“Dolomites of theoretical composition’. A comparison of the
results of analysis makes this evident.

Dolomite of theoretical Ticknall grey

composition (Skeats). dolomite.
Calcium carbonates Q : . 54-7 57-1
Magnesium carbonate . < . 45:3 38-3
Iron compounds . : : SSS 2:7
Insoluble residue . 5 2 : -033 1-5

In the Ticknall dolomite a small amount of free calcite is present,
as shown by slides stained with Lemberg’s solution.

These rocks are seen best in the old lime works of Ticknall, but
the exposures are very limited in extent, so that the bedded nature
of these dolomites and their apparent non-passage into unaltered
limestone cannot be used as reliable evidence of their origin (d).
There is, on the other hand, not the slightest visible development of
patchy dolomitization (/).

A small fault occurs, but this shows no definite connexion with
the origin of the dolomite. The yellow and grey varieties of the
rock are very similar in their microscopic characters. Sections show
a crystalline mass'in which a large number of crystals have been
rounded off, presumably by simultaneous development (7), but some
rhombohedral outlines are retained, particularly in the case of some
of the larger crystals (micro-photo, Pl. XI, Fig. 3). There are very
numerous inclusions, consisting mainly of minute particles of insoluble
matter incorporated during crystallization (/), but there are no
central nor zonal inclusions of hematite (2), iron oxide in the form
of limonite being interstitial. ‘This feature has special significance
in view of the fact that reddish rocks of Permian and Triassic ages
rest upon the limestone in the north-west corner of the Ticknall
exposures. Chert is absent, and organic remains, if present
originally, have been completely obliterated (7). According to the

1 Numbers refer to stratigraphical positions given in the classification of
petrological types.
2 Q.J.G.S., 1905, p. 105.

and Leicestershire Dolomites. 257

evidence it seems reasonable to infer that the Ticknall dolomites are
of contemporaneous origin.

10. Fossrzirerovus Dotomitic Limesrones or TIcKNALL AND CALKE.

Certain limestones occurring at a slightly lower horizon than that
of the barren dolomites of ‘icknall, are interesting mainly on
account of their representing an incomplete stage in the process of
dolomitization. ‘These limestones are best studied at Ticknall, but
some of the Calke specimens yield very fine slides showing
‘‘selective’’ phenomena. The amount of magnesium carbonate
does not exceed 16 per cent. As in the case of the barren dolomites
above, these rocks occur apparently in definite beds and are not
associated with faulting of any importance. Chert is absent.
Microscopic sections show idiomorphic crystals of dolomite having
a fair degree of purity (4), and devoid of zonal hematite in-
clusions (/). ‘The rhombohedra show a decided preference for organic
structures (p), both coralline and brachiopod, though dolomitization
occurs to sume extent in the matrix. Micro-photo, Pl. XI, Fig. 4,
shows rhombohedra developed in organic structures, the matrix
consisting of recrystallized calcite in places. Though the features
shown by this photograph are typical, some individual crystals are
developed partly in an organism and partly in the matrix. The
rock being of a mixed organic nature, there is no knowledge of the
relative proportions of aragonite and calcite muds in the original
matrix, and even if this point could be decided there would still be
the question of the comparative stability of coarser aragonite and of
calcite mud to be determined. In one or two cases dolomite crystals
are entirely surrounded by recrystallized calcite, from which it
appears that either the recrystallization took place after the
formation of dolomite or recrystallized calcite has been converted
into dolomite. The inference that dolomitization was prior to re-
crystallization would tend to support the theory of contemporaneous
origin. The selective phenomena exhibited by the Ticknall
and Calke dolomitic limestones do not, in my opinion, yield any
conclusive evidence concerning the period of dolomitization, and
though the balance of evidence derived from other sources may be
slightly in favour of contemporaneous alteration, it may be wiser to
consider the matter ‘‘not proven”’ since some of the evidence is of
a conflicting nature.

Having arrived at the general conclusion that most of the
dolomites of the Leicestershire area are of contemporaneous origin,
may I suggest that they appear to have been formed in shallow
portions of the Carboniferous sea situated in the Charnwood region.
The dolomitic nature of these rocks compared with that of the more
normal limestones occurring at the same horizons (D, and D,) in
Derbyshire may thus be explained. The case may be somewhat
similar to that of the Jaminosa dolomites of the Bristol area, which
are situated about twenty-five miles distant from the more normal
limestones of the Mendips. ‘The presence of a rich Lamellibranch
fauna in the D, subzone in Leicestershire, and the presence of only

DECADE VI.—VOL. V.—NO. VI. 17

258 Dr. J. Allan Thomson—The genus Bouchardia,

a few feet of Carboniferous Limestone at places south of Osgathorpe
as shown by a boring at Desford where the Carboniferous Limestone
- was found to rest on Pre-Cambrian, supply evidence that shallow-
water conditions existed in the area during Carboniferous times.

EXPLANATION OF PLATE XI.
MICROPHOTOGRAPHS OF THE LEICESTERSHIRE DOLOMITES.
Fic. 1.—Red dolomite, Breedon, Leicestershire. Idiomorphic rhombohedra,
having central zonal inclusions of hematite and fairly clear outer
zones. X 25.

,, 2.—Red dolomite, Breedon. Calcite of crinoid ossicle invaded by fine-
grained hematite-bearing dolomite. Matrix completely dolomitized.
x 25.

,, 3.—Grey dolomite, Ticknall, south - eastern border of Derbyshire.
A mosaic of rather allotriomorphic grains devoid of zonal hematite
but having many dusky inclusions. A few rhombohedral outlines
are shown. A little limonite is interstitial. x 25.

», 4,—Fossiliferous dolomitic limestone, Calke Park, Derbyshire. Typical
section showing preference of dolomite for organic structures. The
matrix is partly composed of recrystallized calcite. x 25.

IIl.—Tue cenus Boucnarpié (Bracwiopopa) AND THE AGE OF THE
YouneEeR Brps oF Seymour Istanp, West ANTARCTIC.

By J. ALLAN THOMSON, M.A., D.Se., F.G.S., Director of the Dominion
Museum, Wellington, N.Z.

Tue AGE oF THE YouNGER Breps oF Seymour ISLAND.

HELLS with the external aspect of Bouchardia have been known
for some time from the New Zealand Tertiary (Oamaruian),
and were first described by Hutton in 19051 under the names
of Bouchardia rhizoida and B. tapirina.2, The correctness of this
generic ascription was doubted by von Ihering, who stated that
the shells lacked the characteristic external form of Bouchardia.*
In this, however, von Ihering was mistaken, probably owing to the
unsatisfactory nature of Hutton’s figures, for these species agree
externally with Bouchardia in the very characters which he supposes
they lack, viz., the very sharp beak ridges, the more or less straight
sides, and the presence of a longitudinal cord over the suture of the
deltidial plates. The most characteristic external feature of the.
shell of Bouchardia is that the sharp beak ridges unite in an apex
dorsally of the foramen, i.e. the foramen is epithyrid. In Hutton’s
supposed Bouchardie the foramen is permesothyrid, but almost
epithyrid. .
Buckman‘ has described a number of species of Bouchardia from
the younger beds of Seymour Island, West Antarctic, and having to
rely practically on these alone for a determination of the age of the
beds, and finding no help in the way of direct zoological comparison,
he has been forced to fall back on a biological argument.

1 Trans. N.Z. Inst., vol. xxxvii, p. 480.

” Not Waldheimia tapirina, Hutton, 1873.

3 Ann. Mus. Nac. Buenos Aires, t. xiv, p. 473, 1907.

* Wissensch. Ergebn. Schwed. Siidpolar-Exped., Bd. iii, Lief. vii, pp. 14-17,
32, 1910.

Grou. Maa., 1918. IPM SCI.

G. S. Sweeting, photo.

Bale, tip

LEICESTERSHIRE DOLOMITES.

Seymour Island, West Antarctic. 259

“The Bouchardie, however, may be looked at from another aspect
—the biological: their stage of development may be considered.
In this respect they are intermediate between Bouchardie found in
the Patagonian and in the Oligocene of New Zealand on the one hand,
and the living Bouchardia rosea on the other; in fact they are, so far
as biological development is concerned, much more advanced than
the Patagonian Oligocene species, and much nearer in development
to the present-day form.

‘©The character of the Bouchardie is wholly against their being
earlier than the Bouchardie of the Patagonian. Biologically speaking,
the Bouchardie of the Patagonian are earlier than the Antarctic
Bouchardia, for they agree with the young stage and differ from the
adult stages of these shells. Then the Bouchardie of the New
Zealand Oligocene are certainly further removed from the Antarctic
forms; they appear to be biologically earlier than the Patagonian
species.”

Recently I have been able to show’ that the New Zealand supposed
Bouchardieé possess Magellaniform loops and septa, and further that
in a series of shells with similar beak characters there are repre-
sentatives with all stages of loop development between those of
Bouchardia and Magellania. Arguing that the constancy of beak
characters shows that we are dealing with a stock which has attained
the Magellaniform loop in its highest member by a different line of
ancestry from Veothyris and Magellania, I proposed new generic
names for representatives of each loop stage as follows :—

Magadina: Genotype Magadina browni, Thomson. Loop Magadini-

form, i.e. so-called Magadiform of Beecher.

Magadinella: Genotype Wagasella woodsiana, Tate. Loop Tere-

bratelliform.

Rhizothyris: Genotype Bouchardia rhizoida, Hutton. Loop

Magellaniform.

Buckman? has since shown that in’the position of the foramen
there is development from the hypothyrid, through submesothyrid,
mesothyrid, and permesothyrid to the epithyrid ‘position. In this
respect, therefore, Rhizothyris is less advanced than Bouchardia, and
does not necessarily belong to the same stock. The similarity
between them in beak characters is simply that in each the foramen
is very advanced in position, and this may be and is the case in
widely different stocks. Zaqueus, for instance, also possesses a
permesothyrid foramen, and is certainly no close relation of
Rhizothyris.

Buckman’s biological argument, therefore, is weakened by the
inclusion of the New Zealand species of Rhizothyris, but it still stands
if confined to species which there is no reason to suspect are not true
Bouchardia. The most primitive in shape is B. patagonica, von
Ihering, from the Salamancan (Upper Cretaceous) of Patagonia; then

1 “*Brachiopod Genera: The Position of Shells with Magaselliform Loops
and of Shells with Bouchardiform Shape’’: Trans. N.Z. Inst., vol. xlvii,
pp. 392-4038, 1915.

ZEA ISE Buckman, ** Terminology for Foraminal Development in Terebratu-
loids (Brachiopoda)’’: Trans. N.Z. Inst., vol. xlviii, pp. 130-2, 1916.

260 Dr. J. Allan Thomson—The genus Bouchardia,

follow in order B. gttteli, von Ihering, from the lower Patagonian,
B. transplatina, von Lhering, from the Entrerian of Patagonia, along
with Buckman’s Antarctic species, next the New Zealand Upper

Oamaruian species described below, and finally B. rosea.

- Asa matter of fact, however, no such biological argument for the
age of the Seymour Island beds was necessary, since a direct zoological
comparison could have been made between B. transplatina, von
Thering,! and B. angusta, Buckman, which are hardly distinguishable
from the published figures. In the absence of other evidence, this
would justify the age of the younger beds of Seymour Isiand being
placed as Entrerian, i.e. distinctly younger than the Patagonian and
probably Upper Miocene, which is practically where Buckman
placed them.

A New Spectres or BoucwArpra From NEw ZeEaranp.
Bouchardia minima, sp. nov. (Fig. 1.)
Shell elongate oval or elliptical, generally much longer than wide,
greatest width about the middle, sides rounded in the broader forms,

a b c

Tlie. 1.—Bouchardia minima, Thomson. Mt. Brown Beds, Waipara District,
North Canterbury, New Zealand. (a) Holotype, dorsal view; (b) holotype,
lateral view ; (c) paratype, interior of dorsal valve, ventral view. Enlarged
6 diameters.

nearly straight in the narrower forms, front rounded, commissures
with a low broad anterior sinuation. Valves rather depressed, the
ventral slightly more convex than the dorsal and obscurely carinated.
Hinge-line short and curved, beak short, acute, not incurved, beak
ridges rather blunt, foramen minute, epithyrid, deltidial plates
obscure, a groove running between the umbones of the two valves.
Surface of valves smooth with a few moderate lines of growth,
indicating development from a subcircular through an oval to an
elliptical shape.

Interior of ventral valve :—Hinge teeth prominent, bifid, consisting
of upper and lower processes separated by a well-marked groove ;

1 H. von Ihering, ‘‘Les mollusques fossiles du Tertiaire et du Crétacé
supérieure de |’Argentine’’?: Ann. Mus. Nac. Buenos Aires, t. xiv, pp. 480-1,
1907. Buckman unfortunately overlooked this reference in drawing up his
bibliography.

Seymour Island, West Antarctic. 261

there is a slightly raised ridge along the median line of the anterior
part of the valve, probably separating the muscular impressions,
which are not clear.

Interior of dorsal valve:—Posterior part much thickened with
elevated solid cardinalia bounded on each side by deep hinge sockets
which converge posteriorly. As in other species of Bouchardia,
distinct socket ridges, hinge plates, cardinal process, etc., cannot be
certainly distinguished. It would perhaps be more correct to term
the socket walls in this case hinge teeth of the dorsal valve, for there
is on each side a rounded projecting ridge which fits into the groove
in the bifid teeth of the ventral valve. The space between the socket
ridges is filled with shell matter, forming a solid platform, above
which rises a median boss or cardinal process, rounded anteriorly,
but with a small posterior tongue. From the sides of this boss two
narrow ridges converge to meet near the umbo. In the anterior end
of the solid hinge platform there are three caves entering from the
floor of the shell, a larger and deeper median one and two smaller
lateral ones, separated by two small projections. The high median
septum is situated anteriorly and touches the median projection from
the floor of the ventral valve. Itrapidly lessens in height posteriorly
and projects into the median cave of the hinge platform without
uniting with the latter. On the anterior end of its elevated portion
it bears a small swollen boss. No sign of the descending brachial
arms has been observed in any of the numerous specimens examined.

Dimensions in millimetres :—

Length. Breadth. Thickness. |

Holotype . : c : 4-5 3 1:5

Paratypes . : Boer ane 4-5 3 2
We ‘ E : : 5 4 1-8
of a ; 5 é 4 3 1-5

Type locality.—Base of main limestone, cuesta between Mt. Brown
aud the Waipara River, North Canterbury.

Material.—A large series (several hundreds) from the type locality,
all from one small cave in the limestone; a few specimens from the
same horizon in the Weka Pass end of the district; a small series
from Flat Top Hill, Oamaru District, Otago.

Horizon.—The main Mt. Brown limestone is near the top of the
sequence of Oamaruian beds of the Weka Pass and Waipara district,
and probably correlates with the Hutchinson Quarry beds of Oamaru.
It may therefore be called Upper Oamaruian. The limestone of Flat
Top Hill is Ototaran, i.e. Middle Oamaruian. The Middle and Upper
Oamaruian are by general consent Miocene.

Zoological comparison.—Bouchardia minima is to be compared with
the other elongate species of the genus, from which it differs by the
narrowness and curvature of the hinge-line. B. antarctica, Buckman,
is an elongate form with a broad, nearly straight hinge, then follow
with narrower and more curved hinges &. attenuata, Buckman,
B. rosea (Maine), and finally B. minima, in the order named. If the
development of elongation as revealed by the growth-lines is con-
sidered B. minima must be placed before #. rosea, since the youthful
growth-lines are broader in the former.

262 Dr. J. Allan. Thomson—The genus Bowchardia.

REMARKS ON THE GENUS BOUCHARDIA.

Since an external form similar to that of Bouchardia may be
combined with a more advanced loop, it is necessary before a given
species can be certainly referred to the genus to have some knowledge
of the interior arrangements. The loop is known only in the recent
species B. rosea, and consists of two “anchor-shaped disconnected
curved lamelle’’ fixed to the posterior end of a high septum. These
lamelle resemble those of the ascending portion of the loop of Dagas,
and in both genera they are disconnected, and not united to form
a ring as in Dagadina and in the Magadiniform and pre-Magadiniform
stages of Terebratella.' The descending branches of the loop, which
are complete in Magas and Magadina, are totally absent in B. rosea.
Beecher has compared the early pre-Magadiniform stages of Tere-
bratella with the adult loop of Bouchardia, but there is this important
difference, that in the young of TZeredratella the growth of the
descending branches commences before that of the ascending
branches, and there is never a stage in which the ascending branches
do not form a complete ring or hood on the septum.

If Bouchardia is correctly placed in the Magellanine, B. rosea must
be looked upon as a retrograde species, descended from a form
possessing a complete ring on the septum and incomplete descending
branches, and now attaining a less instead of a greater caleifieation
of the loop than its forerunners. If this view is correct, the loops
of the fossil species of Bouchardia may be expected to show a greater
calcification than exists in B. rosea. This expectation is not realized

‘in B. minima, for numerous interiors of this species are available,
but show no trace at all of a loop except a slight swelling on the
posterior end of the septum which closely resembles the first stage of
the hood in the young of TZerebratella rubicunda. If this is a correct
homology, then Bouchardia minima represents a still earlier loop stage
than B. rosea, but is apparently also degenerate in that the descending
branches are not calcified, since these appear first in the Terebratelli-
form development. The septum does not unite with the cardinalia ~
in B. minima, which supports the view that its brachidium is in
a less advanced stage than that of B. rosea.

Buckman states that many of the Antarctic Bouchardie examined
by him were in such condition as to show the internal characters,
but, unfortunately for the purposes of this discussion, he has given
no further information than may be gleaned from an enlarged view
of the interior of B. angusta. The characters of the cardinalia seem
essentially similar to those of B. minima in the smaller of the two
figures given, but little can be made of the nature of the loop if any
exists. The case is still worse for B. sitteli, von Ihering, for von
Ikering’s figure is far from satisfactory. The interiors of the other
species ascribed to Bouchardia have not been described or figured.

Von Ihering in 1907 argued from the then known distribution of
Bouchardia only in the Salamancan and Patagonian of Patagonia and

' Cf. P. Fischer & D. P. Oehlert, ‘‘ Mission scientifique du Cap Horn
(1882-3): Brachiopodes’’: Bull. Soc. Hist. Nat. d’Autun, t. v, pp. 254-334,

1892. J. A. Thomson, “ Additions to the knowledge of the Recent Brachiopoda
of New Zealand’’s Trans. N.Z. Inst., vol. xlvii, pp. 404-9, 1915.

Dr. F. R. Cowper Reed—The genus Homalonotus. 268

the Recent seas of Brazil that the genus originated in Patagonia.
Since that date fossil representatives have been found in the West
Antarctic and in New Zealand, but in younger beds than the
Patagonian. Towards the end of the Miocene, then, the genus must
have had a wide distribution in the Southern Ocean, which there is
considerable reason to believe was much warmer than at present.
Whether it attained this distribution by dispersion from Patagonia
or not is hardly a matter for profitable discussion at present, since
little or nothing is known of the Upper Cretaceous Brachiopods of
New Zealand and the Antarctic.

IV.—Nores on THE GENUS HOMALONOTUS.
By F. R. COWPER REED, Sc.D., F.G.S.

INCE Salter,’ in 1865, published his classification of the specics
of the genus Homalonotus, no detailed attempt has been made to
re-arrange the increased number of species now known into natural
groups. Salter was not convinced that his scheme was satisfactory,
and appears to have regarded it as largely artificial, though con-
venient. The divisions instituted or recognized by him bore the
names Brongniartia, Salter, 1865 (divided into two sections) ;
Trimerus, Green, 1832; Kenigia, Salter, 1865; Dipleura, Green,
1832; and Burmersteriva, Salter, 1865.

Koch & Kayser,? in 1883, after describing the Lower Devonian
species of the genus from the KRhenish area and other regions,
criticized Salter’s system. The separation of Homalonotus and
Trimerus was not considered sound, but Dipleura was acknowledged
to mark a distinct group. The Lower Devonian species were
grouped into two divisions, the first one containing two sub-
divisions, Homalonotus (which was regarded as equivalent to
Burmeisteria) and Trimerus; the second division was formed by
Dipleura. Primary importance was attached to the position of the
point of section of the lateral margin or genal angle by the facial
sutures, and secondary importance to the degree of furrowing of
the py vidium. In the first division the facial sutures cut the
margin in front of the genal angle, the thoracic axis is broader
than the pleural lobes, the pyg gidium is parabolic with a blunt or
pointed extremity, and has its axis and pleural lobes deeply
furrowed. The presence or absence of spines distinguished the two
subdivisions of this group. In the second division the facial sutures
cut the middle of the genal angles, the pleural lobes are as wide as
the axis, and the pygidium is bluntly rounded and either smooth
or only weakly furrowed.

Bigot,’ in 1888, recognized three sections of the genus, for which
he employed Salter’s group-names Brongniartia, Homalonotus sens.
str. (= Kenigia), and Trimerus, but he revived Corda’s name

1 Salter, Mon. Brit. Trilob., 1865, pp. 104, 105.

2 Koch & Kayser, Abh. geol. specialk. Preuss., Bd. iv, Heft ii,
pp. 73-157, 1883.

3 Bigot, Bull. Soc. Géol. France, ser. 11, vol. xvi, pp. 419-35, 1888.

264 Dr. F. R. Cowper Reed—The genus Homalonotus.

Plesiacomia for a species H. brevicaudatus (Desl.), which he regarded
as of independent generic rank.

Hall,*in the same year, acknowledged only one genus Homalonotus,
and in his list of references quoted as synonyms Dipleura, Trimerus,
Plesiacomia, Brongniar tia, and Kenigia.

Pompecki,? in 1898, put Calymenella, Bergeron, 1890, as a sub-
genus of Homalonotus, but did not refer to other previously
established subgeneric groups.

Woodward,* in 19038, repeated Salter’s definition of the genus
(with a few alterations) in connexion with his remarks on British
Devonian species, and recognized Salter’s group, Burmeisteria,
as valid.

Giirich,* in 1908, allowed only one genus, Homalonotus, but took
Brongniartia, Trimerus, and Kenigia as denoting subgenera of the
Ordovician and Silurian periods.

Moberg & Gronwall,®> in 1909, discussed Salter’s system of -
classification of Homalonotus in connexion with their description
of H. Knight.

In 1909 Giirich ® introduced a new subgeneric name Digonus for
a Devonian group of species, and he considered the subgenera
Dipleura and Burmetsteria as worthy of retention.

Woods,’ in the same year, regarded Homalonotus, Synhomalonotus
(Pompecki, 1898), and Calymene as of equal rank and placed them in
the family Calymenide, but did not mention any subgeneric divisions.

Raymond,® in 1913, gave as three separate genera the groups
Homatlonotus, Trimerus, and Dipleura; but Beecher, in the earlier ©
edition (1900) of the same textbook, mentioned only one genus,
Homalonotus, with Trimerus as a pubpentis:

A new Brazilian and Turkish subgenus of Lower Devonian age
was established by Clarke,® in 1913, under the name Schizopyge, and
the same author employed the name Homalonotus to include the
type-species of Salter’s Burmeisteria.

ae SUBGENERIC, OR GROUP-NAMES IN USE.
. Homalonotus, Konig, 1825.

The type of the genus Homalonotus chosen by Konig is H. Knighté
Konig,” of the Upper Ludlow beds of England and Sweden. But

the generic name has been used for many years in a comprehensive

* Hall, Paleont. New York, vol. vii, p. xxiii, 1888.
2 Pompecki, Neues Jahrb. f. Miner. Geol., Bd. i, pp. 235-43, 1898.
* Woodward, Grou. MAG., Dec. IV, Vol. x, p. 28, 1903.

* Giirich, Leitfossilien, Lief. i, Camb. Silur., p. 70, pl. xxvi, figs. 1-3, 1908.

2 Moberg & Gronwall, Om Fyled. Gotlands, Lunds Univ. Arssk., N.F.
Af. ii, Bd. vy, No. 1, pp. 72- 7, 1909.

& Giirich, Leitfossilien, Lief. ii, Devon, pp. 155-7, 1909.

7 Woods, Orustacea and Arachnids, vol. iv, Camb. Nat. Hist., section
Trilobita, p- 249, 1909.

: ® Raymond, in Kastman-Zittel’s Textbook of Paleontology, vol. i, p. 724,
19138.

® Clarke, Foss. Dev. Parana (Mon. Serv. Geol. Miner. Brasil, vol. i),
pp. 89-101, 1913.

10 Konig, Icones Sectiles, 1825, pl. vii, fig. 85.

Dr. F. R. Cowper Reed—The genus Homalonotus. 265

manner, including many species which differ widely from the type.
For this reason Salter,’ in 1865, was led to suggest a new name,
Kenigia, for the section characterized by H. Knighti, and its
characters are discussed below under that heading. Other authors
have not been so precise, and Hall’s? definition of Homalonotus strove
to be wide enough to embrace the various divergent sections or
groups, and has, therefore, a more extended application: ‘‘ Body
usually large, produced, depressed above, with abruptly sloping sides.
Axial furrows indistinct or obsolete. Surface smooth or spinose.
Cephalon depressed-convex, wider than long; genal angles rounded ;
anterior margin somewhat produced; glabella subrectangular, smooth,
or with faint lateral furrows; eyes small, situated somewhat back
of the middle of the shield; the facial sutures run from the genal
angles over the eyes, converging towards the frontal margin, where
they are connected by the transverse frontal suture, thence they
continue to the edge of the doublure where they meet, thus inclosing
a small, free, subtriangular plate. Thorax composed of thirteen
deeply suleate segments. Pygidium smaller than the cephalon,
elongate triangular, posteriorly rounded or slightly produced. The
axis bears usually from ten to fourteen annulations. Pleurz smooth
or with posteriorly sloping ribs.” This definition, however, is not
entirely satisfactory, for it is not applicable to the early Ordovician
species, in which the axial furrows are distinct, and the number of
segments in the pygidium fewer than stated. Hall also seems to
regard the commissure uniting the facial sutures in front as not
a part of them but as a new and separate structure, and he fails to
remark that the epistomal sutures are distinct. His ‘‘subtriangular
plate”? is the epistome or rostral shield. It should, moreover, be
added that the thoracic pleure always have rounded ends, and that
the pygidium exhibits two main and separate types, one semicircular
or semi-elliptical and simply rounded, the other triangular and
acuminate behind.

The point of section of the margin by the posterior branch of the
facial suture is also of some importance; Hall shows it in his
diagrammatic woodcut as bisecting the rounded genal angle; but this
is not always the case, as Koch (op. cit.) noticed and used as a basis
of classification.

Salter’s* earlier definition in 1865 makes no reference to the
pygidial characters nor to the facial sutures, but it says that the
genus is distinguished from Calymene, ‘‘its near ally,” by its want of
distinct trilobation, and goes on to state that ‘‘ Homalonotus is elongate,
convex, with steep sides and a very broad axis, scarcely distinguished
from the pleure. There are thirteen body-rings deeply grooved, and
the fulerum is close to the axis in most of the species. The head
with an obscure quadrate glabella, slightly lobed; a rostral shield;
and a quadrate labrum (= hypostome) tuberculate and gibbous in
the middle and with a bilobed tip. Surface of the body scabrous,

1 Salter, Mon. Brit. Trilob., p. 106.
2 Hall, Palesont. New York, vol. vii, p. xxiv, 1888.
3 Salter, Mon. Brit. Trilob., p. 104.

266 Dr. F. R. Cowper Reed—The genus Homalonotus.

occasionally spinous. Internally the cheeks have at their base
a broad flat space next the glabella”’.

Raymond (op. cit., 1918, p. 724) defines Homalonotus as follows:
*“ Axial lobe wide, cephalon short and trilobate in front, cheeks
forming high mounds crowned by the eyes.” Apparently he had in
his mind H. Knight, and at any rate this definition would not include
any of the Ordovician species, and none of them can be put in
Trimerus or Dipleura, which are the only other Homalonotid genera
which he quotes.

Woodward,' in 1903, practically repeated Salter’s definition in
slightly different phraseology, saying: ‘‘ The peculiar trilobation of
the body-rings, so conspicuous in most genera, is very indistinct
in Homalonotus, especially in the thoracic segments, although in
some species it is better marked in the pygidium. The shape of the
body is elongate, convex, with steep sides and a very broad axis,
scarcely distinguished from the pleure. There are thirteen body-
rings, deeply grooved, and the fulcrum is close to the axis in most of
the species. ‘he head is triangular, with an obscure quadrate
glabella slightly lobed and a quadrate labrum; the surface of the
body is scabrous, occasionally spinous. The pygidium is generally
narrow and pointed, except in a few species which have a more
rounded contour.” He goes on to say that ‘‘of the twenty species
recorded, by far the larger number are from the Silurian”. It will
be shown in this paper that the climax of the development of the
genus is in the Devonian period, where the number of species and
the diversity of types are greatest.

2. Trimerus, Green, 1832.

The type of this section or subgenus is the well-known ZZ. delphino-
cephalus, Green,* first described from the Niagara Limestone of New
York and subsequently recognized in the Wenlock Limestone of
Dudley (according to Salter? it is the Woolhope Limestone). Salter
(op. cit.) defined this section as follows: ‘‘ Elongate, convex, with
triangular head; eyes not remote; a defined but obscurely lobed
broad glabella. Thorax slightly lobed; tail many ribbed, pointed,
often acuminate.” Raymond (op. cit., p. 724) merely states that the
‘“‘cephalon is longer than in the preceding [i.e. Homalonotus |, not
trilobate in front, free eheeks narrow’’. There seems to be some
difference in the British and American specimens as regards the
glabella, for Hall‘ does not mention or figure any glabellar lobes or
furrows in his description of the Niagaran types, while in most of the
Dudley specimens two pairs of more or less faint subcircular lateral
swellings, not touching the axial furrows, are present on the
posterior half of the glabella and seem to represent the two posterior
pairs of lateral lobes, and there is also a weak trace of the first.
lateral furrows.

The peculiar subcircular areas on each side of the base of the

Woodward, GEOL. MAG., Dec. IV, Vol. X, p. 28, 1903.

Green, Monthly Amer. Journ. Geol., vol. i, p. 559, pl. O, fig. 1, 1832.
Salter, op. cit., p. 115.

Hall, Paleont. N.Y., vol. ii, p. 309, pl. Ixviii, figs. 1-14.

1
2
3
4

Dr. F. R. Cowper Reed—The genus Homalonotus. 267

glabella, such as Salter! specially noticed in the South African species
H. Herscheli, are also present in HH. delphinocephalus; these areas may
be marked off by a faint curved furrow or have a slight independent
convexity, but are also distinguished from the rest of the cheeks by
their smoothness and absence of pitting. They may be termed the
paraglabellar areas (for further remarks see Aenigia and Burmeisteria).

The epistomal sutures are very short on the upper surface of the
head-shield and usually difficult to distinguish, but they are at right
angles to the conjoint facial sutures and arise in front at a distance
apart rather less than the anterior width of the glabella.

The course of the facial sutures themselves on the head-shield is
usually well seen; Hall (op. cit.) describes them as “ parallel and
coincident with or slightly within the flexure of the margin, passing
then obliquely through the eyes and turning [to] come to the margin
a little above the posterior angle of the head-shield’’. They meet in
front on the upper surface at an angle forming a more or less pointed
Gothic arch close to the anterior margin and leaving a wide area
before the glabella.

In one specimen in the Sedgwick Museum (Tablet No. 114) from
the Wenlock Shale of Dudley, the inferior surface of the front part of
the head-shield is shown; the doublure, which is broad, flattened
and subcrescentic in shape with the posterior margin forming a
double sigmoidal curve, reaches back to the front end of the glabella;
the epistomal sutures are straight and converge posteriorly, thus
defining a flat elongated triangular epistome which does not appear
to have been described or figured in the case of British examples of
the species.

In the case of the thorax of the type-species it should be mentioned
that each segment of the axis has an anterior articulating band
which is separated off by afurrow which bends back gradually before
reaching the axial furrows and crosses the pleura obliquely. The
axial furrows of the thorax are not in the same longitudinal line as
those defining the glabella, for the axial furrows of the head-shield
on crossing the occipital ring diverge obliquely outwards. There
are, however, no well-defined axial furrows at all on the thorax,
faint longitudinal depressions only being present in conjunction with
a slight constriction of the pleura. At this point also, on each
segment, there is situated the inner angle of the large triangular
articulating facet extending to the end of the pleura and forming
a bevelled flattened surface with a sharp, angulated posterior edge
which crosses the pleural furrow obliquely without diverting its
course. Barrande’s* figure of a body-ring of HH. delphinocephalus
gives an erroneous idea of its characters, for it fails to show that the
furrow which marks off the articulating band on the anterior of the
axial ring, is continued across the pleuraand articulating facet as
the pleural furrow. Hall (op. cit.) describes it more clearly than
Salter, who does not make it plain that this furrow is continuous.

Of other species referable to this section Salter mentions two,
H. Johannis, Salt., and H. cylindricus, Salt., both from the Silurian.

1 Salter, Trans. Geol. Soc., ser. I, vol. vii, p. 216, pl. xxiv, fig. 1c, 1856.

° Barrande, Syst. Silur. Bohéme, vol. i, pl. v, fig. 10.

268 Dr. F. R. Cowper Reed—The genus Homalonotus.

The former, however, should be placed in the section Kenigia
according to the structure of the front margin of the head-shield,
which Salter failed to observe from want of well-preserved specimens.
But H. eylindricus is undoubtedly a member of Zrimerus so far as its
pygidium is concerned, and it was on this part that the species was
based. Salter’s' outline-sketch of a middle-shield (of which the
specimen cannot be traced), which he thought might belong to this
species, shows the facial sutures uniting in front in a much flattened
curve, but there is nothing in other respects to prevent its reference
to the same section as H. delphinocephalus.

3. Dipleura, Green, 1832.

This section or subgenus was founded on the well-known American
species H. Dekayi, Green,? from the Hamilton Group (Middle
Devonian).

Salter (op. cit., p. 105) defines the section as follows: ‘‘ Convex,
head wide, semi-oval or subtriangular, with somewhat pointed front.
Glabella narrow, well defined. Eyes rather remote, on gibbous
cheeks. ‘Thorax slightly lobed. ‘Tail obtuse, hardly ribbed.”’ No
British representatives are recorded, but Salter refers to it the
Continental species H. obtusus, Sandb., and probably Z. crassicauda, —
Sandb., and H. Ahrendi, Roem.

Raymond (op. cit.) briefly defines Diplewra as follows: ‘‘ Axial
lobe wide, pygidium smooth.”

Hall* has given a full description of the species, and we may
quote his description of the course of the facial sutures: ‘‘ The facial
sutures take their origin on the lateral margins of the doublure in
front of the genal angles and pass inward, parallel to the posterior
margin of the cephalon, to the eye, thence forward with a broad
curve inward to the anterior margin at the base of the prora, bending
thence on to the epistomal doublure, meeting at its inferior margin.
The branches of the facial suture are united on the upper surface of
the prora by a straight transverse frontal suture, thus leaving a free
median plate upon the epistoma, which is elongate-subtriangular in
outline, attenuate at the apex, and recurved at the base, which
forms the anterior portion of the prora.” The connecting ‘frontal
suture”? here described, judging from the manner in which the
facial sutures bend inwards and are connected in front of the
glabella in H. noticus, Clarke, and other species, must be regarded as
merely the anterior deflected part of the facial sutures, while the
so-called continuations of the facial sutures over the anterior edge
which bound the epistomal plate laterally on the inferior surface of
the head-shield must correspond with the epistomal sutures of other
species.

Here, as in //. ornatus, H. rhenanus, and other Devonian species,
the flattening of the anterior curve of the anterior conjoint portion
of the facial sutures gives a spurious appearance of an abnormal

’ Salter, op. cit., p. 117, fig. 28.

2 Green, Mon. Trilob. N. Amer., 1832, p. 79, pl. i, figs. 8, 9.

3 Hall, Paleont. New York, vol. vii, p. 7, pl. ii, figs. 1-11; pl. iii, figs. 1-5;
pl. iv, figs. 1-6; pl. v, figs. 1-10, 1888.

Dr, F. R. Cowper Reed—The genus Homalonotus. 269

transverse and nearly straight special suture on the upper surface of
the head-shield. It is not clear if Hall regarded this ‘‘ frontal
suture” as a new independent commissure originating by itself, but
he apparently believed the facial sutures did not meet on the upper
surface of the head-shield, but that they were directly continued by
the epistomal sutures extending on to the inferior surface.

With regard to the existence of any distinctive features of this
section, the structure of the epistomal doublure resembles 7. delphino-
cephalus, and the thorax seems almost identical; but, as Hall (op. cit.,
p- 10) remarks, Dipleura differs from the Homalonoti of the earlier
Devonian and Silurian of America and Europe in the obsolescence
of the annulations of the pygidium at maturity. The hypostome is
subquadrate, with the posterior margin broadly excavated, and is
much like that of Zr. delphinocephalus. The glabella has three pairs
of lateral furrows, which become obsolete at an early stage of growth.
As regards the structure of the head-shield and the flattened anterior
junction of the facial sutures, we may compare H. rhenanus, Koch,'
and H. ornatus, Koch,? but as regards the obsolescence of the pygidial
axis we see an approach to H. levicauda, Quenst.,* though the head-
shield and outline of the pygidium are distinct in that species.

Kayser, in a footnote to Koch’s paper (op. cit., p. 10), rightly
points out that the Rhenish Devonian species H. crassicauda, Sandb.,
and H. Ahrendi, Roem., mentioned by Salter under Dipleura, do not
strictly belong to this group on account of their strongly ribbed
and acuminate pygidia, but that A. Schustert, Roem.,* may be
referred to it.

4, Brongniartia, Salter, 1865.

The definition of Brongniartia given by Salter® is as follows:
‘‘ Depressed, with broad rounded head, remote eyes, well-defined
lobeless urceolate glabella, and many-ribbed rounded tail.”

Two divisions were established by Salter with the following brief
summary of characters: ‘‘(1) Body scarcely trilobed; the axis
broad (ZH. bisulcatus is the type of the subgenus and of this section) ;
(2) body strongly trilobed; the axis narrow (type, H. rudis; this
leads off directly towards Calymene).”

Before discussing the characters and value of this subgenus proposed
by Salter we must remark that it is unfortunate that he chose the
preoccupied name Brongniartia. For J.each in 1824 used it for a genus
of Coleoptera, and Katon* in March, 1832, proposed it for a new genus
of Trilobites, of which his Brongniartia carcinodea’ was chosen as
the type. The latter species, however, is now considered as identical
with Green’s Zriarthrus becki. Katon in June of the same year

Koch, op. cit., p. 32, pl. iii, figs. 1-3.

Ibid., p. 23, pl. ii, figs. 1, 2.

Koch, op. cit., p. 55, pl. viii, fig. 4.

Roemer, Beitr. z. Kennt. Nordwest Harz., iii, t. iii, fig. 20, 1855.
Salter, op. cit., p. 104.

Eaton, Amer. Journ. Sci., ser. I, vol. xxii, p. 165, 1832.

Eaton, Geol. Text-book, 2nd ed., June, 1832, p. 33, pl. i, fig. 3.

NJ aoe Wwnm

270 Dr. F. R. Cowper Reed—The genus Homalonotus.

figured as further examples of the genus the Trilobites B. platy-
cephala’ (= H. Dekayi, Green) and B. ‘sotelea? (= Asaphus
platycephalus, Stokes). Vogdes* puts B. platycephala, Eaton, as
a synonym of H. delphinocephalus, Green. It is obvious from these
facts that the name Brongniartia cannot be retained for Salter’s
group of Homalonotus.

The type of the group must now be considered. This species,
Hf, bisuleatus, was founded by Salter * on specimens in the Geological
Society’s Collection and in the Woodwardian [Sedgwick] Museum,
Cambridge. The first figured specimen, a middle-shield (op. cit.,
fig. 24), is stated in the text of McCoy’s Synopsis to be from the
‘‘Caradoe Sandstone, Wittingslow, near Acton Scott, Shropshire’’,
but in the explanation of the plate is stated (in error) to be from
‘‘S.W. of Pwllheli”. The imperfect thorax and pygidium depicted
in his fig. 26 and the separate pygidium (fig. 27) are from the same
locality in Shropshire, and all these three specimens are in the
Geological Society’s Collection, now in the British Museum (Natural
History), South Kensington. The specimens from which figs. 25 and
28 were drawn are in the Sedgwick Museum, and came from the
Welsh locality south-west of Pwllheli. Three other specimens
(figs. 29-31) are referred by Salter to a variety B minor, and are
also at Cambridge. But the chief point to be emphasized is that
the species is undoubtedly founded on the Shropshire specimens, and
it is by them that its characters are fixed. ©

Salter ® in his monograph in 1865 figured several examples from
other Welsh localities, but stretched the limits of the species in
including some of them; the first figures on his plate (pl. x,
figs. 3, 4) are of those specimens from Wittingslow which he had
used in his previous description in 1852 and had there figured.

In his first subsection of Brongniartia Salter put also his species
Hf, Sedgwicki and H. Edgelli ; the former was founded on two broken
middle-shields in the Woodwardian Museum and calls for no special
mention in this place, except with regard to the much flattened and
wide curvature of the union of the facial sutures, which makes the
head-shield (as Salter says) truncate in front and unusually broad.
The second species was founded on a pygidium, but a doubtful
middle-shield from Horderly was also ascribed to it.

We must, however, return to a consideration of the characters of
the typical H. bisulcatus, for Salter’s first description in 1852 is too
brief, and his second description in 1865 is inaccurate, for it includes
the ambiguous Welsh specimens, some of which at any rate ought
probably to be separated off. Confusion is introduced by Salter’s
conflicting statements that the ‘‘ body is scarcely trilobed ”’ (p. 104)

1 Eaton, op. cit., pl. ii, fig. 20.

2 Tbid., pl. ii, fig. 22.

° Vogdes, Bibliogr. Paleoz. Crust. (Occas. Papers Calif. Acad. Sci., iv,
p. 311, 1898); Weller, Bull. iv, pt. ii, Nat. Hist. Surv., Chicago Acad. Sci.,
1907, p. 200.

4 Salter, Appendix to M‘Coy’s Syn. Brit. Paleoz. Foss. Woodw. Mus., 1852,
p. v, pl. iG, figs. 24-8.

> Id., Mon. Brit. Trilob., 1865, p. 105, pl. x, figs. 3-10.

Dr. F. R. Cowper Reed—The genus Homalonotus. 271

and that the ‘‘trilobation is conspicuous but not deep” (p. 105).
The latter statement is made for the type species and is incorrect,
the axial furrows being very shallow and the pleural portions of the
thorax scarcely marked off from the axis in the general convexity of
the body. Inthe pygidium, however, the axis is well defined, has an
independent convexity and well-marked though not deeply impressed
axial furrows. In the thorax the axial furrows form continuous
depressions, but each axial ring is independently marked off from its
pleura by a short oblique transverse furrow corresponding to the one
crossing the neck ring from the base of the glabella, which Salter
mentions and shows in his figure (woodcut 24 on p. 106). The base
of each pleura is somewhat swollen in the angle between this
transverse furrow and the pleural furrow which is a lateral continua-
tion of the furrow separating off the articulating band on the axial
ring. There is a peg-like interior projection situated on the posterior
margin of the thoracic ring just inside the posterior end of the short
transverse furrow, and this peg or knob fits into a small corresponding
notch on the anterior margin of the succeeding ring. Salter shows
this structure (op. cit., pl. x, fig. 16) in his figure of a segment of
HH. Brongniarti, Des]., but does not describe it in connexion with
H. bisulcatus.

In the case of the pygidium the shape is semi-oval or parabolic in
all the typical Shropshire specimens; the so-called ‘‘ young one”
from North Wales, figured by Salter (op. cit., pl. x, fig. 8), is certainly
different. Salter’s description of the typical form, however, is correct,
and it is important to notice that the axis is composed of 11-12 rings
and is continued to the margin by a ‘‘ conical appendage” or post-
axial angulated triangular piece. There is also a distinct (though
very narrow) flattened or gently concave border, not sharply defined
from the rest of the pleural lobes, but the pleure do not cross it.
The first sulcus crossing the lateral lobes is a direct continuation of
the one on the axis which separates off the articulating band at its
front end; we may therefore suspect that the second similar strong
one is of the same nature, and therefore not a true interpleural furrow
but homologous with the pleural furrows of the thorax. This opens
up a curious question as to the nature of the so-called pleurs on the
pygidium. It was from the presence of these two strong furrows
that Salter termed the species bisulcatus.

The original Welsh specimens from the Bala beds south-west of
Pwllheli which Salter referred to Hf. dbisuleatus and figured as such in
1852' are undoubtedly distinct from the Shropshire types; the
middle-shield (fig. 25), by its breadth, shortness, and flattened anterior
edge, suggests a reference to 7. Sedgwick, and ‘perhaps the pygidium
(fig. 28), may belong to the same species. But both specimens are
poor, crushed, and distorted.

The other Welsh specimen figured as H. bisulcatus in his mono-
graph in 1865 (pl. x, fig. 6) is likewise much distorted; it is from
Moel y Garnedd, Bala, and together with some similar fragments in
the Jermyn Street Museum (;5;, 3%, 3%-) from the same locality may
belong to a new species.

1 Salter, op. cit., pl. iG, figs. 25, 28.

272 Dr. F. R. Cowper Reed—The genus Homalonotus.

The so-called ‘‘ young specimens’’ from Wales which Salter figured
in 1865 (pl. x, figs. 7, 8) must certainly be separated from the
typical H. bisulcatus and are the same as Salter figured in 1852! as
his var. 8 minor from Maes Meillion. The poor specimen in the
Sedgwick Museum from the Arenig beds of Ty Obry, figured? as
H. bisulcatus with a query, is of very doubtful specific and even
generic reference.

In the head-shield of the typical Shropshire examples of H. bzsui-
catus the facial sutures unite very close to the margin, or actually
along its edge in a broad flattened curve leaving a wide pre-glabellar
area at least one-third the length of the glabella. There is therefore
no distinct, much less large, pre-sutural area, the free-cheeks and the
front end of the epistome apparently forming only a very narrow
band on the edge of the head-shield in front. Bailey* shows this
band in a figure of a specimen from the Bala beds of the Onny River.
But the inferior doublure, the epistome and epistomal sutures have
not been observed or described in any specimen, and in the majority
of specimens of the head only the middle-shield is preserved. ‘The
elabella, which is urceolate, does not show any lobation, and ‘para-
glabellar areas”? are absent or practically obsolete, but I have seen
faint indications of them in a head-shield (No. 5) from Marshbrook
in the Ludlow Museum.

A species referable to the same group as ZH. bisulcatus is
H. ascriptus, Reed,* from the Dufton Shales of Melmerby, but it is
only founded on head-shields somewhat resembling Salter’s var.
B minor of H. bisuleatus to which reference has above been made.

The middle-shield doubtfully referred by Salter to H. Hdgelli
(Salter, op. cit., pl. x, fig. 10, p. 108) and obtained from the Bala
beds of Horderly, must also be placed here.

—A new species allied to H. Sedgwicki, from the Bala beds of the
Vyrnwy Dam, near Rhayader, has been recognized in the Sedgwick
Museum, and the description of it under the name H. Tawney? is now
awaiting publication.

The second section of Brongnartia has as its type H. rudis, Salter,”
which was founded on two extremely imperfect and distorted casts of
pygidia from Capel Garmon, Denbighshire, in the Sedgwick Museum.
The Welsh specimens in the Jermyn Street Museum, which Salter
mentions (op. cit.) as belonging to this species and some of which he
subsequently figured in his monograph in 1866 (op. cit., pl. x, fig. 12,
Nantyr, Llanarmon ;%;; pl. x, figs. 14a, 6, Cader Dinmael 3%), are
likewise very poor; the second figured one is, however, better than
the original types. The strongly and well-defined axis to the thorax,
and the shorter pygidium with fewer axial rings and fewer pleural
ribs are features separating it from the species H. bisulcatus. But

1 Tbid., pl. i, figs. 29, 30.

2 Salter, Mem. Geol. Surv., vol. iii (2nd ed., 1881), p. 526, pl. 11a, fig. 8.

> Bailey, Fig. Char. Brit. Foss., i, pl. xiii, fig. 9a, 1875.

+ Reed, Gkou. MAG., Dec. V, Vol. VII, p. 216, Pl. XVII, Figs. 4-8, 1910.

° Appendix to M‘Coy’s Syn. Pal. Foss. Woodw. Mus., p. y, pl. if,
figs. 20, 20a.

Dr. F. R. Cowper Reed—The genus Homalonotus. 278

H. rudis is an unsatisfactory species owing to the impossibility of
drawing up a proper diagnosis from the original material.

The pygidium (No. =; Mus. Pract. Geol.) figured by Salter in 1865
(op. cit., pl. x, fig. 14) from the ‘‘Caradoc Grits of Cressage,
Shropshire”’, as probably referable to H. rudis, must certainly be
separated, and may belong to the new species H. diserratus Reed MS.
(the description of which awaits publication), but its edges are broken
and imperfect.

The other British species referred by Salter to the second section
of Brongniartia are the two from Budleigh Salterton pebbles
described as H. Brongniarti, Deslong.,’ and H. Vicaryi, Salter.’
A third? unnamed species is described by Salter from the same
locality, and a fourth from Gorranhaven,* both the latter being
represented only by pygidia. According to Bigot,> Salter’s
H. Brongniarti, Desl., is not the same as Deslongchamps’ type,
but is referable to H/. serratus, de Trom. The figures and description
of H. vulcani (Murchison), promised by Salter (op. cit., p. 113) have
never been published ; it is stated® ‘‘to occur in the voleanic grit on
the west flank of Corndon Mountain in a ravine east of Middleton ”
but I have not been able to trace the specimen.

The species of Homalonotus from the Grés de May, Normandy,
including those from the British pebbles in the Budleigh Salterton
Triassic conglomerate, and also those from Gorranhaven, belong to
a group somewhat distinct from the typical Brongniartia, though
(as stated above) Salter put them in his second section. They seem
to be the earliest representatives of the genus, apart from any of the
questionable genus Wesewretus. The characteristics of the group are
the strong trilobation of the thorax and pygidium, and the short
transverse or semicircular shape of the pygidium, together with its
composition of few segments, and its vertical or steeply inclined but
not completely infolded doublure. It may also be mentioned that
the pleure on the pygidium are occasionally separated by furrows
right up to the edge of the doublure, and sometimes show traces
of division at their ends, and that the furrow which marks off the
articulating band at the front end of the axis is continued laterally
as a strong furrow across the large bevelled articulating facet at the
anterior lateral angles of the pleural lobes. In the case of the head-
shield it appears that the facial sutures cut the lateral margins
slightly in front of the genal angles, which are well rounded; the
glabella is parabolic, semioval, or rounded-trapezoidal, and the axial
furrows are not sinuated as in //. bisulcatus. The facial sutures
unite in front marginally or just inside the margin in a regular
uninterrupted curve, which may or may not be flattened. Most, if

1 Salter, Quart. Journ. Geol. Soc., vol. xx, p. 290, pl. xv, figs. la, b, 1864 ;
Mon. Brit. Trilob., p. 110, pl. x, figs. 15-17 ; pl. xiii, fig. 9.

eet bide pa klale pl. xiii, fig. 10.

3 Tbid., p. 112, pl. x, fig. ‘18.

4 Ibid., p- 112, woodcut, fig. 26.

> Bigot, Bull. Soc. Géol. France, ser. 111, vol. xvi, p. 427, 1888.

5 Murchison, Silur. Syst., 1839, p. 663; id., Siluria, 2nd ed., 1859, pl. ii,
figs. 3, 4.

DECADE VI.—VOL. V.—NO. VI. 18

274 Dr. F. R. Cowper Reed—The genus Homalonotus.

not all, of the species seem toshow no glabellar lobes, though Salter !
describes furrows and lobes in his H. Brongniartz, Des.

In H. Deslongchampsi, de Trom., Moriére? describes the thoracic

pleure as having a little angular projection at the point where they

begin to bend back, which fits into a notch in the preceding pleure,

but it is not clear from Bigot’s descriptions and figures (op. cit.)

if this structure is present in other species.

The Gorranhayven specimens,* which are most probably referable to
this group, are too poor for precise determination.

Barrande* in his supplement figures and describes a perfect.
individual of the Ordovician species H. bohemicus, Barr.,’ from Stage
Dd 2, which Salter referred to the second subdivision of Brongniartia,
and this specimen is particularly interesting because it shows the
epistomal sutures starting at right angles from the points at which
the facial sutures bend inwards near the anterior margin and crossing ~
the pre-sutural band to pass to the inferior surface of the doublure.
We may, with much probability, assume that the closely allied other
species of this group have the structure of the front of the head-
shield and the behaviour of the sutures on a very similar plan.

A considerable number of species seem to belong to this group,
and all those marked* come from the Grés de May or its undoubted
equivalents :— :

*H. serratus, de Trom. 2H. Viellardi, De Trom.

*H. Bonnisenti, Moriére. ?H. draboviensis, Novak” (Bohemia).

*H. incertus, Bigot. ?H. bohemicus, Barr. (Bohemia).

*H. Brongniarti, Desl. HA. Brongniarti, De Vern. non Desl.®

*H. Vicaryt, Salt. (from Sierra Morena).

*H. Deslongchampsi, de Trom. H. buserratus, Reed, sp. nov.,

*H. Morierei, Bigot. Shropshire.

*#H. besnevillensis, Bigot. H. {| Neseuretus| quadratus (Hicks),
HT. Barroisi, Lebesc.® Ramsey Is.

5. Kenigia, Salter, 1865.

The type of Salter's section Kenigia is H. Knighti, Konig, of the
Upper Ludlow Beds of England and Sweden, which Konig chose as
the type of his genus Homalonotus. The latter name is now generally
employed in a more comprehensive manner, the characters of
HH. Knighti being extremely uncommon and scarcely representative
of the whole assemblage of species. The name Kenigia therefore
seems desirably applicable in this restricted sense to the group of forms
resembling H. Anighti. Salter included his H. ludensis in Kenigia,

1 Salter, Quart. Journ. Geol. Soc., vol. xx, p. 290, pl. xv, fig. 1, 1864.

2 Moriére, Bull. Soc. Linn. Normandie, ser. III, vol. viii, p. 383, pls. i, 11,
1884.

* Collins, Trans. Roy. Geol. Soc. Cornwall, ee p. 53 (reprint).

* Barrande, Syst. Silur. Bohéme, Suppl. 1, p. 37, pl. i, fig. 6.

° Barrande, Syst. Silur. Bohéme, vol. i, p. 380, pl. xxxiv, figs. 40-2.

S menescontal Bull. Soc. Géol. France, ‘ser. III, vol. xiv, p. 801, pl. xxxvi,
figs. 12, 13, 1857.

i Novak, Bohm. Trilob., i (Beitr. Paleont. Oest. Ung., Bd. iii, 1881), p. 27,
t. vill, figs. 9a-c.

8 De Verneuil, Bull. Soc. Géol. France, ser. Tit, vol. xii, p. 971, pl. xxiii,
fig. la, 1855.

° Konig, Icones Sectiles, 1825, pl. vii, fig. 85.

Dr. F. R. Cowper Reed—The genus Homalonotus. 275

but this reference seems unwarranted, the head-shield so far as we
know it not possessing any of the typical characters. The definition
of Kenigia given by Salter’ was as follows: ‘‘ Convex; head wide,
transverse, with concave and tricuspidate front, glabella subquadrate,
well-defined; eyes rather approximate, on gibbous -cheeks; tail
pointed, many ribbed.’ Salter? described the species H. Knighti
at some length, but he did not give a clear description or figure
of the peculiarly characteristic structure of the anterior part of
the head-shield, which is well seen in some British specimens.
Moberg & Gronwall*® published some better illustrations of this
trilobite, and showed distinctly the peculiarities of the anterior
margin and the course of the facial sutures. It is seen that the
remarkable tricuspid front is due to the median projection of the
anterior end of the epistome (= rostral shield) which is bounded on
each side on the inferior surface by the epistomal sutures. The
triangular lateral projections are formed by the anterior ends of the
free-cheeks being angulated forwards, and also bent up and down in
a zigzag manner. ‘The marginal doublure thus has an unusual
angulated appearance in a frontal as well as in a superior view. The
facial sutures unite by a transverse commissure before a very narrow
pre-glabellar area, and this transverse suture (which must be regarded
as the direct continuation of the true facial sutures bent rather
suddenly inwards) consists of two gently sigmoidal halves meeting in
the middle at an angle so as to form a small median point. The
sudden change in the direction of the facial sutures may be due to the
more rapid forward growth of the lateral portions of the head-shield
as compared with the median portion, and may be directly connected
with the anterior projection of the front ends of the free cheeks on
the margin.

A similar tricuspid front and projecting epistome is found to exist
in the species H. Johannis, Salter,* as an examination of the types
and other specimens from the original locality in the Jermyn Street
Museum proves; Salter did not show this tricuspidation in his figures,
the anterior end of the epistome of his specimens being imperfect,
and the lateral projections of the anterior margin of the head-shield
being blunter and less prominent than in H. Knightt. But he
figured the inferior doublure and epistomal sutures clearly in his
figures 2 and 7.

A character of some importance which is present in H. Knighti
and less distinctly in WZ. Johannis, is the more or less circumscribed
subquadrate or rounded area on each side of the base of the glabella.
These areas are differently ornamented to the rest of the head-shield,
and resemble in position and shape the “‘alar’’ areas of Harpes.
But to avoid prejudging their homology they are here termed the
paraglabellar areas. We shall have occasion to remark on their
presence in other subgenera.

1 Salter, Mon. Brit. Trilob., p. 106.

2 Tbid., p. 119, pl. xii, figs. 2-10, pl. xiii, fig. 8.

3 Moberg & Grénwall, Om Fyled. Gotl., Lunds Univ. Arssk., N.F., Af. ii,
Bd. v, No. 1, pp. 72-7, pl. v, figs. 1-4, 1909.

* Salter, op. cit., p. 117, pl. xiii, figs. 1-7.

276 R. M. Deeley—Mountain Building.

The trilobation of the thorax is nearly lost in H. Anightc (which
is paralleled by H. planus, Sandb., otherwise quite distinct), and the
axis of the pygidium is scarcely marked off from the lateral lobes,
the axial furrows in both cases being almost obsolete. The elongated
triangular shape of the pygidium, its numerous annulations, and its
produced and pointed extremity are features which are common also
to Trimerus, Digonus, and Burmeisteria, sens. str., as noticed below.

H. Johannis differs from H. Hnighti in possessing a broad pre-
glabellar area, which results in the head-shield haying a triangular
appearance instead of being transverse and so much shortened as to
be broader than long. In consequence of the length of the head
being not thus abnormally reduced, the convergent facial sutures
approach each other in front more closely before bending abruptly
inwards to form the transverse commissure. We shall observe a
similar modification in members of Digonus and Burmeisterva..

The hypostome of H. Anightc has been figured by Lindstrom,’ and
is of the same type as that of H. (Zrimerus) delphinocephalus.

(To be continued.)

YV.—Moounrain Boripine.
By R. M. DEELEY, M.Inst.C.H., F.G.S.

N an article by Dr. H. Jeffreys in the Gronoercan Maeazine for
April, pp. 215-19, an attempt is made to show that the discovery
of radio-active materials in the earth’s crust favours the ‘‘ contraction
and puckering” theory of mountain building. With regard to
O. Fisher’s view he writes, ‘‘It rests entirely on Kelvin’s theory of
the cooling of the earth, which has had to be completely revised on
account of the discovery of the extensive distribution of radio-active
matter in the earth’s crust. The time available has been found to
be about twenty times greater than on Kelvin’s theory, and the
cooling has therefore had time to extend to a much greater depth
and to produce a very much greater compression.” We are also
told what the reduction in the earth’s diameter has probably been,
and the actual depth of Fisher’s level of no strain.

Reference is also made to the three very valuable and interesting
papers by Arthur Holmes published in the Geonoeican Macazine.
But Holmes is by no means as dogmatic as Dr. Jeffreys. Holmes
writes: ‘‘If each grain of the earth’s substance were as rich in radio-
elements as are the rocks which have been examined, the earth’s
total output of heat from this source alone would, in any given
period, be about 300 times as great as the amount actually lost by
conduction to the surface and radiation into space.”

‘This astonishing result pulls us up sharply, for it is manifestly
absurd to believe that our planet is becoming hotter at the appalling
rate implied in these figures, or, indeed, that it is becoming hotter at
all.’ To get over the difficulty it is suggested that the radio-active
elements only exist in the outer portion of the crust of the earth, and
in quantities insufficient to cause the earth to become hotter, and

' Lindstrém, Handl. k. Svensk. vet. Akad., Bd. xxxiv, No. 8, p. 57, t. iv,
figs. 20, 21, 1901.

Notices of Memoirs—A Triassic Isopod Crustacean. 277

Dr. Jeffreys takes this suggestion to be a fact, and would have us
believe that the thickness of this radio-active layer has been fairly
accurately measured and that consequently it is possible to calculate
the depth of the level of no strain.

The discovery of radio-active elements in the rocks of the earth
has not rendered the compression theory any more probable. In its
naked simplicity it appears to show that the earth is getting hotter
and increasing in diameter at an ‘“‘appalling rate”. Iam inclined
to agree with Holmes that the radio-active elements are mainly
concentrated near the earth’s surface; but think that the exact
amount of concentration is uncertain. An expanding earth would
account for the formation of ‘‘ rift valleys’’, normal faults and lines
of volcanic activity or crustal weakness.

The theory I have supported to the effect that the folding and
contortion of the rocks of the earth’s crust have been largely due to
vertical flow resulting from denudation and horizontal flow by the
spreading of elevated areas, would account for the peculiarities our
rocks present even if the earth were slowly expanding.

Dr. Jeffreys states that “substances possessing any elasticity are
called solids’. ‘If it is absent . .. the substance is a fluid.”
Contrast this statement with the following from Maxwell’s Theory |
of Heat, edited by Lord Rayleigh, p. 802: ‘‘Gases and liquids, and
perhaps most solids, are perfectly elastic, as regards stress uniform
in all directions, but no substance which has yet been tried is
perfectly elastic as regards shearing stress, except perhaps for
exceeding small values of the stress.” Dr. Jeffreys will find that the
difference between a solid and a liquid is clearly stated on p. 303 of
the above quoted work. Both solids and liquids are brittle and
elastic. This can, in the case of a liquid, be clearly seen as regards
pitch, but not in the case of water; but all liquids are elastic even
under tangential stress.

In my article on ‘‘ Mountain Building” which Dr. Jeffreys
criticizes, I did not venture to introduce any new theories concerning
the properties of matter, and I think that my critic should have
pointed out that his views are not those of our textbooks. To my
mind his theories concerning the solid and liquid states are quite
inadmissible.

NOTICHS OF MEMOTRS.

i

A Trrasstc Isopop CrusrackAN FRoM AUSTRALIA.

A Fossit Isopop BELONGING TO THE FRESHWATER GENUS PHREATOICUS.
By Cuas. Cuinron. Journ. Proc. Roy. Soc. N.S. Wales, li,
pp. 865-88, 13 text-figs., 1918.

F the six (or perhaps seven) sub-orders composing the order
Isopoda, only the Flabellifera and Valvifera have been definitely
recognized in a fossil state. ‘The Flabellifera are represented by
several genera as early as the Jurassic, while the Valvifera are known
only by a single species from the Oligocene. Professor C. Chilton
now announces the discovery, in the supposed Rhetic rocks of New

278 Notices of Memoirs—A Triassic Isopod

South Wales, of a representative of the remarkable little sub-order,
the Phreatoicidea. ‘To make clear the importance of this discovery
itis necessary to give a brief account of the existing members of the
group.

The genus Phreatotcus was established thirty-five years ago, by
Professor Chilton himself, for a blind species which he found
inhabiting subterranean waters in New Zealand. Other species,
some of them blind and some with functional eyes, were subsequently
discovered in streams and lakes of New Zealand, New South Wales,
Victoria, and Tasmania, and two species of terrestrial habitat were
also found. Three of the species were referred to as many genera
distinct from Phreatoicus and forming with it the family Phreatoicide,
for which Mr. Stebbing in 1893 established the Tribe (now ranked
as a sub-order) Phreatoicidea. In 1914 Mr. K. H. Barnard greatly
extended the known range of the group by discovering a species of
Phreatoicus living in streams on Table Mountain at Cape*Town.

Fie. 1.—Phreatoicus australis, Chilton. Recent. Mt. Kosciusko, New
South Wales. x 4. (After Chilton.)

The Phreatoicidea are distinguished from all other Iscpods by
having the body more or less compressed from side to side, and
resembling in general appearance that of an Amphipod. This
resemblance, however, is no more than superficial, and the structure
of the animals shows that they are in no way closely related to the
Amphipoda.

As in nearly all Isopods, seven somites are distinct in the thoracic
region, and the telson is not separated from the last abdominal
somite. In the Phreatoicidea, however, the first five abdominal
somites are not only distinct and movable but they are of con-
siderable size. ‘This is of some importance as a primitive character,
since the abbreviation of the abdominal region is one of the most
characteristic features distinguishing the Isopoda from the other
orders of Malacostraca.. Even when, as in many Flabellifera, the
abdominal somites are distinct from one another, they are crowded
together, and the greater part of the length of the abdomen is
formed by the enlarged terminal segment. ‘The great development
of the side-plates (pleura) of these abdominal somites in the
Phreatoicidea, and the fact that they are directed downwards
instead of laterally, are characters of less morphological significance,
but they contribute to the Amphipod-like aspect. Another character

Crustacean from Australia. Le)

that may be regarded as primitive is found in the first or coxal
segments of the thoracic legs. ‘These are all of small size and, on
the last six segments at any rate, are movably articulated with the
body. In this character the Asellota resemble the Phreatoicidea,
but in other Isopods these segments are expanded into broad ‘‘ coxal
plates’? and more or less completely fused with the somites that
carry them. Finally, the last pair of abdominal appendages (uropods)
' project from near the end of the body as bifurcate styles, like the
uropods of certain Asellota, and still more like those of Amphipods.

In nearly all other respects—in the structure of antennules,
antenne, mouth-parts, thoracic legs, branchial abdominal limbs, and
even sexual appendages—the Phreatoicidea are commonplace Isopoda,
not differing essentially from many representatives of the central
and typical sub-order, the Flabellifera. That they retain certain
features which we believe to be primitive, or which point the way
to groups outside the order itself, has already been stated, but this
is true also of the Asellota and of the Flabellifera, and it is perhaps
impossible to rank any one of these three sub-orders as, on the
whole, more primitive than the others.

Fic. 2.—Phreatoicus wianamattensis, Chilton. Rhmtic(?). St. Peter’s
Brickworks, Sydney. x 34. (After Chilton.)

The habitat and the geographical distribution of the Phreatoicidea
are also noteworthy. Isopods of truly freshwater habitat are few,
and in no other case are they conspicuously different in structure
from marine representatives of the group. With the possible
exception of the single family Asellide, they are scattered, and no
doubt recent, immigrants from the sea. The Phreatoicidea, on the
other hand, are not known to have any near relatives among the
marine Isopoda, and it is this that gives special significance to their
remarkable distribution in New Zealand, South-Eastern Australia,
Tasmania, and South Africa.

In describing the first known species of Phreatotcus, Professor
Chilton stated that the group ‘‘must be of very considerable
antiquity”. This prediction he has now had the good fortune to
verify in a striking manner. The specimens which he describes
were detected by Mr. R. J. Tillyard while investigating the fossil
insect fauna of Queensland and New South Wales, and were found
in the Wianamatta Shale of St. Peter’s Brickworks, Newtown,
Sydney. The strata in which they occur were at first referred to

280 Notices of Memowrs—A Triassic Isopod Crustacean.

the Trias-Jura, and Professor Chilton quotes Mr. Tillyard’s opinion
that ‘‘evidence is accumulating that will probably place them in
the Upper Trias, probably as the nearest Australian equivalent of the
Rhetic ’. Dr. Smith Woodward, who has reported on the fossil
fishes from the same beds, agrees that the fish fauna, if it had been
found in the Northern Hemisphere, could not possibly have been
regarded as of later than Rhetic age.

The largest specimen obtained must have measured about 30 mm.
in length when complete. After examining a long series of
specimens, Professor Chilton shows that, in the general form and
segmentation of the body, the large size cf the abdominal somites
with their downwardly directed side-plates, the size and shape of the
terminal segment and the uropods, the short antenne (or antennules),
and the form and proportions of the chief segments of the legs, the
fossils closely resemble the living Phreatoicidea. There is indeed
nothing to forbid their inclusion in the type-genus, to which he assigns
them under the name Phreatowcus wianamattensis.

It seems probable from the presence of insects, of such Mollusca
as Unio, and of numerous plant remains, that the beds in which the
fossils are found are of freshwater or estuarine origin, so that even as
early as the Triassic period the Phreatoicidea had adopted, or were
on the way to adopt, the freshwater habitat to which they are at the
present day confined.

While Phreatotcus is thus one of the oldest, if not the very oldest,
of fossil Isopods yet discovered, and while it undoubtedly presents
certain primitive structural characters, it should be noted that it
throws no light on the phylogeny of the order. It is, indeed, very
far from being an ancestral type, and it only emphasizes the fact that
the evolution of the group goes a very long way back in geological
times. No doubt among these early Isopods, as among those now
living, a vast number of forms were two small and too delicate in
structure to be readily preserved as fossils, and, except for some
lucky chance, it is likely that we may never be able to trace, with
any clearness, the lines of evolution followed by the various
sub-orders.

In reporting the discovery of a species of Phreatoicus living at the
Cape, Mr. K. H. Barnard called attention to its probable bearing on
the antiquity of the group and referred to the former extension of
‘‘Gondwana land” over the areas where species of the genus now
occur. We-now learn that they existed, probably as freshwater
animals, within the same area at a time when that extension may
have been still unbroken. Whether at that remote epoch their
geographical range was still wider, we cannot tell. If it was, then
it becomes a most extraordinary coincidence that their fossil remains
should first be found in a district where the living animals exist
to-day.

Reviews—Petrography of the Pacific Islands. 281

RAV LTHWS-

-].—PerrrograpyHy oF THE Paciric Istanps. By R. A. Daty.
Bull. Geol. Soc. America, vol. xxvii, p. 825, 1916.

iB this paper the author puts forward a proposal for a complete
scientific exploration, geological, botanical, zoological, and
anthropological, of the islands composing the regions of Polynesia,
Melanesia, and Micronesia. ‘These are scattered over an area
composing nearly one-sixth of the earth’s surface, and the information
at our disposal concerning them is still very incomplete. The greater
part of the paper is taken up by a discussion of the petrography of
this vast region, so far as itis known. It is pointed out that what
may be called “ continental” rocks, namely, plutonic, metamorphic,
and sedimentary types apart from coral-rock, are only found in islands
lying to the west of a line joining the easternmost of the Fiji group
to the Mariana Islands: all of these are fragments of an ancient
continent that broke up in Tertiary times.

In several hundred other islands volcanic rocks have been recorded :
all the known occurrences are tabulated, and it appears that the
dominant types are olivine-basalt and pyroxene-andesite. Many
other varieties related to these, mostly of basic composition, have
also been recorded, and it is suggested that the andesites and the
ultrabasic lavas are differentiates of a primary basaltic magma under-
lying the whole Pacific basin. The scarcity of acid lavas is
noteworthy: it suggests that in this region the ordinary crust of
quartzose sediments found in continental areas is absent. This is
‘In accordance with the high density of the Pacific area as shown by
geodetic observations. From the evidence adduced it is clear that
this is a pre-eminently subalkaline province, and the author’s
well-known theory of syntectic differentiation brought about by
absorption of limestone is applied to explain the genesis of a certain
number of occurrences of typically alkaline rocks, such as basanite,
nepheline-basalt, and varieties containing hatiyne.

IJ.—Tuser Minerat Inpusrrizs or tHE Unirep Starrs. Sunpsur:
AN ExampitE or Inpusrrian INDEPENDENCE. By JosrepH LE.
Poeur. Bulletin 102, pt. i, United States National Museum
(Smithsonian Institution). pp. 10 and 3 plates. Washington,
1947.

f|VHE falling off in the imports of sulphur from Sicily and of
pyrites from Spain consequent on the War has led to a great

development of the home supplies of sulphur in the United States,

and particularly of the native sulphur deposits of the Gulf Coast
region in Louisiana and Texas. Here the sulphur occurs in dome-
shaped masses in association with petroleum, rock-salt, and gypsum.

Many of the domes consist of a core of rock-salt with lenses of

gypsum and masses of limestone containing petroleum. In two

instances, at Sulphur, La., and Bryan Heights, Texas, bores showed
the presence of great masses of pure sulphur beneath several hundred
feet of quicksand. These masses are supposed to be essentially of

282 Reviews—The Geology of Pigeon Point, Minnesota.

igneous origin, and the doming of the rocks is attributed to the force
of crystallization of minerals from supersaturated solutions. ‘he
petroleum, however, is probably of later date. Since for various
reasons ordinary mining is impossible, the sulphur is extracted by
the Frasch process, which consists essentially in forcing superheated
water through a pipe to the sulphur horizon and lifting the sulphur
by means of compressed air, when it is pumped into large bins to
cool and then loaded straight into trucks. Under the present
abnormal conditions it is possible that much of this exceptionally
pure sulphur will have to be used for the manufacture of sulphuric
acid, an uneconomic proceeding which would be quite unjustifiable
in normal times. kw

IlI.—Tue Grotoey or Pickon Pornr, Minnusora. By R. A. Daty.
American Journal of Scrence, vol. xliii, p. 428, 1917.
fI\HIS paper gives the results of a further investigation of the

well- imown intrusion of Pigeon Point, originally described by
Bayley (Bulletin 109, U.S. Geol. Survey). The main problem is as
to the nature of the “red rock”’, a granitoid type with much
micropegmatite. The igneous mass is concluded to be a sill, not
a dyke as supposed by Bayley; its upper and lower surfaces are
found to be concordant with the bedding of the Animikie rocks, into
which it is intruded. The most striking feature is the regular
variation in the character of the rock from below upwards ; the base
is olivine-gabbro, followed by gabbro, intermediate rock, and finally
the highly acid red rock. This variation in composition is due to
gravitative differentiation, acting on a gabbroid magma which had
been modified by assimilation of sedimentary material derived from
the roof of the sill by stoping. The differentiation.is probably
largely due to gas-action: the presence of much gas is shown by
the abundance of drusy cavities, and peculiar ‘‘ribbon’’ injections,
a few centimetres wide, also indicate great pressure in the magma.
In all the rock-types are found xenoliths of Animikie quartzite
coated with a shell of red rock. This suggests a diffusion of silica
from the xenolith into the basic magma. The red rock appears to
have remained liquid longer than the more basic types, owing to
concentration in it of gas, which lowered its freezing-point.
Consequently dykes and veins of red rock are found cutting the
gabbro as well as the sediments. The red rock is not merely fused
sediment as supposed by Bayley. Neither differentiation nor fusion
alone is sufficient to explain all the facts, and the whole phenomenon
is an example of syntexis, that is assimilation followed by differentia-
tion of the mixed magma thus formed. RoR

ITV.—Own a possistE Causa Mrcuanism For HEAVE-FAULT SLIPPING
IN THE CaLIFORNIA Coast-rance Rereaion. By H. O. Woon.
Bull. Seismol. Soc. America, vol. v, p. 214, 1914.

(F\HIS paper has special reference to the origin of the fault-slip
that caused the disastrous San Francisco earthquake of 1906.
The theory is based on the principle of isostatic readjustment

Reports & Proceedings—The Royal Society. 283

following redistribution of mass by erosionand deposit. It is pointed
out that in the Sierra Nevada and in the Coast Ranges denudation is
very active, while most of the material thus set free is deposited
either in the Great Valley of California or in the sea close to the
coast. The overloading must be specially conspicuous in and near
San Francisco Bay. Owing to this overweighting the areas of
deposition undergo down-warping, while the denuded areas tend to
rise, thus involving a compensating creep in the plastic depths. It
is concluded from various lines of evidence that this creep or
undertow must be greater in a direction parallel to the axes of the
ranges than perpendicular to these; accordingly a state of tension is
produced highly favourable to the formation of slip-faults with
lateral displacement, such as the one that formed so conspicuous
a feature of the San Francisco earthquake. A considerable amount
of subsidiary evidence is put forward in support of the main idea,
partly physiographic, derived from a study of Californian topography,
and partly geodetic, depending on the results of many elaborate
investigations of anomalous distribution of gravity and allied
phenomena in this part of the United States.
Ts ube ale

REPORTS AND PROCHEDINGS.-

I.—Tue Royat Socirry.
April 25, 1918.—Sir J. J. Thomson, O.M., President, in the Chair.

The Bakerian Lecture was delivered by the Hon. Sir Charles
Parsons, K.C.B., F.R.S., on ‘‘ Experiments on the Production of
Diamond”’.

In his lecture the author alluded to some of the results of
experiments described in papers by him to the Royal Society in 1888
and 1907, more particularly to those on the decomposition by heat of
carbon compounds under high pressure, and on the effect of applying
pressure to iron during rapid cooling.

A description is given of experiments designed to melt carbon
under pressures up to 15,000 atmospheres by resistance heating and
by the sudden compression of acetylene oxygen flame, also by the
firing of high velocity steel bullets through incandescent carbon into
a cavity in a block of steel.

Allusion is made to experiments on chemical reactions under high
pressure and their results. The pressures occurring in rapidly cooled
ingots of iron and experiments bearing upon this question are dis-
cussed. Experiments at atmospheric pressure and experiments 7n
vacuo are described.

The main conclusions arrived at are: that graphite cannot be
converted into diamond by heat and pressure alone within the limits
reached in the experiments; that there is no distinct evidence that
any of the chemical reactions under pressure have yielded diamond ;
that the only undoubted source of diamond is from iron previously
heated to high temperature and then cooled; and that diamond is
not produced by bulk pressure as previously supposed, but by the

284 Reports & Proceedings—Geological Society of London.

action of the gases occluded in the metal and condensed into the
centre on quick cooling.

A list of about one-half of the experiments is given in the
Appendix.

I1.—Grotoeicat Society oF Lonpon.

April 17, 1918.—G. W. Lamplugh, F.R.S., President, in the
Chair.

The following communication was read :—

‘‘The Evolution of the Liparoceratide.”’ By Arthur Elijah
Trueman, M.Sc., F.G.S.

The Ammonites considered include several sub-parallel series, of
which four genera were indicated by Mr. 8. S. Buckman in Yorkshire
Type Ammonites. The details of ontogeny and the sutures, which |
had not hitherto been compared, have been employed in constructing
tables showing both the biological and the stratigraphical relations
of the various species; a revision of the existing classification is
proposed.

The early members of each series are similar ‘‘ capricorn” forms
with slender whorls and stout ribs (for instance, A. capricornus,
A. latecosta, A. maculatus). In somewhat later examples the
outer whorl is swollen, and has paired tubercles (for instance,
A. heterogenes). From this stage the tendency is to shorten the
period with slender capricorn whorls by accelerating the development
of bituberculation and prolonging the period of pre-costate globose
whorls; thus the most advanced members of each series are stout
bituberculate forms (for instance, A. striatus, A. becher), which do
not pass in development through a capricorn stage.

The following genera may be recognized; each includes ammonites
of the three types mentioned above :—

1. An earlier group, with tubercles paired in the involute stages ;
Radstock (Somerset) is the only British locality where these
ammonites have been found.

Parinodiceras, gen. nov. Elevated whorl, paired tubercles, the inner and
outer rows widely separated. Genoholotype. Ammonites striatus
parinodus, Quenstedt (1884, pl. xxviii, fig. 6).

Gen. noy. Round whorl, with the rows of tubercles placed close together.
Genoholotype, a specimen to be figured as a new species.

2. A later group, with unpaired tubercles in the involute stage.
These genera are most readily distinguished by sutural characters,
namely, the relative depths of the external lobe (EL) and the first
lateral lobe (IL), and by the width of the external saddle (ES).

(a) With narrow ES (not reaching to the outer tubercles).

Liparoceras, Hyatt. TL and EL about equal in depth. Genolectotype,
Ammonites striatus, Bronn.

Becheiceras, gen. nov. Ib deeper than EL. Genoholotype, Ammonites
bechei, Wright. (Lias Ammonites, pl. xli, fig. 1.)

Anisoloboceras, gen. nov. Il much deeper than EL, the ventral lobules
of IL almost meeting under EL. Genoholotype, Anvmonites nautili-
formis, J. Buckman.

_ Reports & Proceedings—Zoological Society of London. 285

(6) With wide KS, reaching to the outer tubercles.

Aigoceras, Waagen. EL and IL about equal in depth, IL symmetrical.
Genolectotype, Ammonites planicosta, d’Orbigny.

Androgynoceras, Hyatt. ILand EL about equalin depth, ILasymmetrical.
Genolectotype, Ammonites hybrida, d’Orbigny.

Oistoceras, S. 8S. Buckman. Ribs with sharp peripheral curve. Suture
similar to Androgynoceras. Genoholotype, Ammonites figulinus,

Simpson.

Amblycoceras, Hyatt. Ribs with slight peripheral curve. IL shallower
than EL. Genoholotype, 4. capricornus, Hyatt, 1900.

These ammonites generally occur in the upper part of the Lower
Lias, where it has been usual to recognize a capricornus zone over-
lying a strvatus zone. Careful collecting has shown, however, that
there are several horizons with capricorn ammonites of different
series and several with the involute forms evolved from them, as

shown below :—

margaritatus zone i\

be) rNh
Capricorn Be
[ Bituberculate ae
davéizone . . “ia ue
9 9
| capicrn ie
99 9
( b rh) 1 99
; Bituberculate
“abee zone . 2.x : ke
Vans we
Bituberculate He

f Bituberculate ammonites of the A. nawtiliformis series.

Ovstoceras.

Oustoceras.

the A. bechei series.

Ajgocerasand Androgynoceras.

Amblycoceras.

Amblycoceras.

Aigoceras, Androgynoceras.

Beaniceras.

Lvparoceras.

Luparoceras.

the first group (with paired
tubercles).

In no locality that has been examined is the complete sequence
shown. The absence of some groups is due to the original distri-
bution of the ammonites; in other cases it is due to non-sequences
(for example, the upper part of the dav@i zone is not represented in

Gloucestershire).

Two groups of Lias Ammonites are recognized, namely: (i) those
‘which were evolved directly from a globose ancestor; this includes
the Liparoceratide, Echioceratide, Hildoceratide, Polymorphide,
Deroceratide ; and (11) those which passed through an intermediate
broad-ventered (cadicone) stage; these include the Amaltheide and

Dactyloidee (with Beaniceras).

IIl1.—Zooroeicat Socrery or Lonpon.
April 9, 1918.—Dr. A. Smith Woodward, F.R.S., Vice- President,

in the Chair.

Dr. A. Smith Woodward, F.R.S., V.P.Z.S., exhibited fossil rostral
teeth of the sawfishes Mopristis and Pristis, and referred to the
progressive changes in the rostral teeth of the Pristide during

geological time.

Mr. G. A. Boulenger, F.R.S., exhibited the head of an example of
Hydrocyon goliath, Blgr., from the Congo, a fish attaining the length
of 4 feet. The object of the exhibition was to show the enormous

286 Correspondence—Ernest Gibson.

shark-like teeth, to which special interest attaches, owing to
a similarity, recently pointed out by Dr. Eastman, to fossil teeth
occurring in the Upper Cretaceous, which would appear to indicate
the existence of Characinide in that geological epoch, a range in
time which Mr. Boulenger had predicted as probable thirteen

years ago.

CORRESPONDENCE.

DEPOSIT OF GRANULAR IRON-ORE ON THE COAST OF
BUENOS AYRES.

Srr,—The newspapers of Buenos Ayres have recently announced
the discovery of a deposit of granulous iron-ore on the Atlantic sea-
board of the province of that name. As the whole Argentine
Republic has hitherto only been able to boast of one genuine occur-
rence of that valuable mineral, in the shape of the famous meteorite
hurled into the Gran Chaco in the north (see section of same in
the Geological Department of the British Museum (Natural History),
South Kensington), popular curiosity was much aroused and excited.

As possibly the subject may contain some points of interest,
I herewith furnish the more important details.

The locality is the sea-coast and both sides of the mouth of the
River Quequen Grande, in (roughly) lat. 38° and long. 58°. And
it is somewhat to the south of the recently named Chapadmalalense
formation, the site of the Ameghino paleontographical controversy.

The total area of the deposits is estimated at some 5,000 hectareas.
It is stated that the magnetic iron-ore is found distributed
through the sand from the surface to an average depth of
10 metres (otherwise to where it rests on the ‘‘tosca” or loéss of
the Pampean formation), and in a proportion of 380 per cent of
mineral. The result, in accordance with these figures, would
represent the colossal amount of 750 millions of tons. “As, however,
the preceding is the commercial phase, or view taken by the parties
who have obtained the concession for exploiting the situation, it Tey
be open to very considerable discount.

I have before me the analysis and reports furnished by various
Government specialists and departments. On account of the length,
etc., of these, I have selected in preference one emanating from
London itself, and which is as follows :—

ANALYSIS OF Two SAMPLES OF MINERAL.
Marked 18. Marked 21.

% %
Silica . : 3 : a : 1-36 1-10
Titanium oxide 5 4 : . 17-66 18-14
Ferrous oxide : 4 ‘ : 74-27 74-11
Manganous oxide . : é ‘ 0:56 0:62
Alumina : i : 4 i: 0-22 0-16
Lime . : i j ‘ 0-38 0-34
Magnesia _ 0-42 0-33
Combined water, aillkalies, and lol 5-13 5-20

100-00 100-00

Obituary—Professor George Alexander Lowis Lebour. 287

A special search was made for sulphur and phosphorus, giving the
figures :—
Marked 18. Marked 21.

% %
Sulphur : : : c : 0-055 0-074
Phosphorus : . : 0-109 0-115

Both samples are titanifero ous iron-ore of moderate quality.
Ernest Gisson.

25 CADOGAN PLACE, LONDON, S.W.1.
May 5, 1918.

ys ICI oryNAS Sa

PROFESSOR GEORGE ALEXANDER LOUIS LEBOUR,

M.A., D.Sc., F.G.S., Vicz-PrincipaL or tHe Armstrong CoLurce,
" Nuweasrun- UPON-TYNE.

BorRN 1847. DIED FEBRUARY 7, 1918.

Y the death of Professor Lebour in his 71st year, on February 7,
1918, the scientific world loses a prominent and interesting
figure. Born in 1847 and educated at the Royal School of Mines,
he served from 1867 to 1873 on the Geological Survey of England
and Wales. He was lecturer in geological surveying at the
University of Durham College of Science (later, Armstrong College)
in Newcastle from 1873 to 1879, and succeeded Dr. David Page as
Professor of Geology in the University. This position he occupied
until his death, so that for forty-five years he was connected with
the College, and for thirty-nine years occupied the chair of Geology.
In 1904 he was awarded the Murchison Medal by the Council of the
Geological Society, and in the same year was elected Vice-Principal
of Armstrong College.

The transference of heat through the crust of the earth occupied
Lebour’s attention early and led to measurements of underground
temperature in northern coal-pits, and also in conjunction with
Herschel, to the determination of the thermal conductivities of
a great number of rocks. This important work, issued in a series -
of British Association reports from 1873 to 1881, is well known, and
many of the data obtained are accepted as standard.

Lebour’s name will always be associated with the geology of
Northumberland and Durham. Besides his official maps, he brought
out in 1877 an excellent geological map of the county of Northumber-
land, which is the embodiment of much strenuous, clear-sighted
labour. He was joint author with William Topley of a widely
quoted paper on the Great Whin Sill, which may be said to have
definitely established its intrusive character. The stratigraphical
relations of the Carboniferous rocks form the subject of many papers,
in which the divisions of the system and the description and
correlation of the important limestones, etc., are set forth with
admirable lucidity. The economic aspects of the subject find
expression in papers on the Redesdale Ironstones and the coals of
the Bernician series, especially those associated with the Little
Limestone. The future importance of these coals, which occur in

eS) Obituary—Robert Mackenzie Johnston.

rocks below the Coal-measures proper, is strongly insisted upon, and
the lapse of forty years has but added strength to the views then
brought forward. Of many papers relating to the Geology of
Durham may be noted those dealing with the classification of the
Salt-measures, the breccia-filled fissures in the Magnesian Limestone
(aptly termed by him breccia-gastes), and the Marl Slate and Yellow
Sands.

As many as nineteen papers are recorded under Lebour’s name in
the GrotogicaL Magazine Index from 1869 to 1887, but he has
contributed over one hundred papers on geological subjects to
various journals. One of these of special interest, published as long
ago as in July, 1876, on ‘“‘ The Carrara Marbles”, gives a most
instructive history of the geological vicissitudes undergone by these
highly metamorphosed Limestone Rocks from their reference to
Eruptive and Cretaceous Oolitic, Jurassic, Liassic, Rheetic, and
finally being assigned to the Lower Carboniferous age by Coquand
on the evidence of fossils. he similar saccharoidal limestones of
St. Béat in the Pyrenees have also been, on the evidence of fossils,
proved to be equivalent to the statuary marbles of Carrara and of
like Carboniferous Limestone age. (Gurox. Mac., 1876, pp. 289-92
and p. 382.)

Lebour wrote ‘‘ The Geology of Durham” in the Vectoria History
and the Handbook to the Geology and Natural History of Northumber-
land and Durham, of which three editions have appeared (1878-89).
It is a very effective monument to his life-work in the two counties,
and has the remarkable merit of increasing in value the more it
is used.

This brief narrative of work accomplished gives, however,. no true
estimate of Lebour’s scientific activity and influence. He was
a many-sided man, of wonderful fluency, both in the written and
spoken word, and a born teacher. His papers are models of clearness
and skilful arrangement of material; they are written in flawless
English, and they often display that sense of humour which was one
of his notable characteristics. These same qualities were, if possible,
accentuated in his lectures. He inspired a great band of workers,
who have carried his methods and enthusiasm to the four quarters of
the globe, and he was ever ready to help, by his sage advice, those
whose steps he had directed towards scientific paths.—From Nature,
February 21, 1918.

He leaves a widow and two daughters with a wide circle of
personal and scientific friends to cherish his memory.

ROBERT MACKENZIE JOHNSTON.

Mr. R. M. Jounsron, the well-known Registrar - General and
Government Statistician of ‘'asmania, was born at Inverness,
educated at the Andersonian University of Glasgow, and went to
Australia at the age of 26. He was the author of many works on
Tasmanian natural history, notably the Systematic Account of the
Geology of Tasmania, 1888. He received the I.8.0. in 1908, and
died at Hobart on April 20, 1918.—Morning Post.

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' GEOLOGICAL, MAGAZINE |

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HENRY WOODWARD,

PROFESSOR J. W. GREGORY,

ASSISTED BY
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Sir THOMAS H. HOLLAND, K.C.L.E., A.R.C.8., D.Sc., F.R.S., VICE-PREs. G.S.

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; JULY,

1918.

GIN SS Ss

I. ORIGINAL ARTICLES.

The Leaves of Noeggerathiopsis,
Australia. By ROBERT ETHER-
IDGE, jun., Director Australian
Museum, Sydney: With a Post-
script by Professor A. C. SEWARD,
M.A., F.R.S., ete. (Plate XIII.)

The Genesis of Tungsten Ores. By
R. H. RAstTaun, M.A., F.G.S.
' (Continued. )

The Pre-Thanetian Erosion of the
Chalk of the London Basin. By
HERBERT A. BAKER, B.Sc.,
F.G.S. (With three Text-figures.)

The Rock-Cliffs and Floors of the
*“Dry’’ Lakes in W. Australia.
By J. T. Jurson, Geological
Survey, Western Australia. (With
two Maps.)

Notes on the genus Homalonotus.
By Dr. F. R. COWPER REED,
vo A., F.G.S. (Concluded.)

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No. VII.—JULY, 1918.
ORIGINAL ARTICLES.

—

IT.—ARrRaNGEMENT OF THE LEAVES IN THE AUSTRALIAN SpEcres oF
NV 0EGGERATHIOPSIS.|

By R. ETHERIDGE, jun., Director and Curator of the Australian Museum,
Sydney.
With a Postscript by Professor A. C. SEwAaRD, M.A., F.R.S., Professor of
Botany in the University of Cambridge.
(PLATE XIII.)

N 1849 Professor J. D. Dana described certain leaves from the
Illawarra District and Neweastle, New South Wales, occurring
in the Upper Coal-measures. To these he gave the name of
Noeggerathia spathulata and WV. media.? Long after, in 1879 to be
exact, Dr. O. Feistmantel established his genus Noeggerathiopsis for
the reception of similar leaves from the Talchir—Kararbari Beds of
the Lower Gondwana System,’ and from his remarks it may, by
inference, be concluded that Dana’s were included in the new genus
also. This inference is justified by Feistmantel’s later definite
reference of these leaves to Moeggerathiopsis;* at the same time he
added another species, VV. prisca, from the Lower Coal-measures at
Greta. He believed them to be closely ailied with Cycadeacee.

It is not my intention to follow step by step the various suggestions
advanced on the systematic position of Noeggerathiopsis, nor express
an opinion on the vexed question of specific identity of the leaves;
suffice it to quote Dr. E, A. N. Arber’s summing up: ‘‘ Considerable
difference of opinion has existed both with regard to the affinities of
this genus and also in respect to the identity of some of its members.
The first Indian specimens were described by Bunbury in 1861, who
referred them provisionally to the Gymnospermous genus Woeggerathia.
This generic name was also at one time adopted by Feistmantel . .
The same author, in 1881, pointed out the close similarity presented
by the leaves described as RAiptozamites, by Schmalhausen, with the

1 Noeggerathiopsis = Rhiptozamites, Schmalhausen (Mém. Acad. Imp. Sci.
St. Petersb., xxvii (7), No. 4, 1879). This identity is admitted by Schenk
(Zittel’s Handbook Pal., ii, Paleoph., p. 330, f.n.); Kurtz (Revista Museo la
Plata, v, p. 130, 1894); Arber (Quart. Journ. Geol. Soc., lviii, p. 19, 1902) ;
Kurtz (Quart. Journ. Geol. Soce., lix, p. 25, 1903).

* Dana, Wilkes U.S. Explor. Exped., Geol. x, p. 715, pl. xii, figs. 9, 10,
1849.

> Feistmantel, ‘‘ Foss. Flora Gondwana Syst.’’? (Pal. Indica), iii, pt. i,
p. 23, 1879.

+ Feistmantel, Paleontograplica, Supp. Bd. iii, Lief. iii, Heft ii, pp. 158,
162, 1879.

DECADE VI.—VOL. V.—NO. VII. 19

¥

x,
A

ry

290 R. Htheridge—Leaves of the Australian

Indian and Australian species of Moeggerathiopsis, and the probable.
affinity of both these genera to the Mesozoic Cycads of the family
— Zamiee.

‘In more recent times, ZeiJler, Seward, Solms- Laubach, and others
have regarded this genus as in all probability a member of the
Cordaitales, closely allied to Cordaites .. .

‘‘Zeiller has made a careful study of the leaves described by
Schmalhausen as Rhiptuzamites. He regards them as belonging to
a true Cordaites, and as distinct from the members of the Glossopteris
flora described here, which, however, they closely resemble in several
TESWE CUS) ce.

‘‘Zeiller has pointed out that the constant occurrence of Cordaitean
seeds of the genera Cardiocarpus or Cardaicarpus in association
with WV. Hislopi, is an additional argument in favour of referring
Noeggerathiopsis to the Cordaitales.” *

One of Dana’s figures exhibits a number of leaves ‘‘ proceeding
from a common base, as if the cluster of leaves growing together,
and perhaps at the extremity of a branch . . . In this cluster, which
is evidently a natural group, the leaves are of different ages .. .
The centre from which the leaves radiate has a shining coaly aspect,
_as if a soft bud or vegetable base of some thickness had been pressed
down and carbonized”’.* On the piece of shale figured there are two
such groups.®

These illustrations of Dana’s do not seem to have attracted the
attention of paleobotanists to the extent one would have expected.
As a matter of fact, I do not remember any direct reference to them
other than that of Tenison Woods,‘ although I think it may be
accepted that Arber’s interesting figure® of a specimen in the Clarke
Collection at Cambridge, and named by McCoy Zeugophyllites elongatus,
but not of Morris, ‘‘a group of three leaves which appear to radiate
from some axis unfortunately missing,” is of the same nature. I am
pleased, therefore, to be now able to supplement Dana’s illustrations
by an account of four clusters, more or less complete.

In Dana’s fig. 9 there are portions of nine or ten leaves (it is
difficult to say how many exactly on the lower side of the figure)
varying from obtusely spathulate to lanceolate-spathulate, but all
narrowed at the base. At the right-hand side of the hand-specimen
is the other fragmentary cluster, but in this instance there is one
entire leaf and traces of three or four others. Unfortunately, these
figures do not afford any evidence of the phyllotaxis, whether these
leaves were in their order spiral, fascicled, or verticillate, or of
their method of attachment, amplexicaul, articulate, or even sub-
amplexicaul. Dana’s suggestion of a cluster of leaves growing at the
end of a branch to some extent suggests a fascicular arrangement,
a suggestion I return to later.

1 Arber, Cat. Foss. Plants Glossopteris Flora Brit. Mus., pp. 178-9, 1905.
2 Dana, Wilkes, U.S. Explor. Exped., Geol. x, p. 715, 1849.

® Dana, ibid., pl. xii, fig. 9.

* Ten. Woods, Proc. Linn. Soc. N.S. Wales, ili, pt. i, p. 117, 1883.

° Arber, Quart. Journ. Geol. Soc., lviii, p. 18, pl. i, fig. 1, 1902.

Species of Noeggerathiopsis. 291

We may now turn to the further examples of Woeggerathiopsis
“leaves. On the specimen illustrated in Plate XIII are two clusters
more or less imperfect, but in both instances the leaves, such as they
are, radiate from a centre, the latter representing Dana’s ‘‘ soft bud,
or vegetable base”. In Fig. 1 of this Plate there are seven leaves,
or portions thereof, lanceolate-spathulate, the terminations of four
in which the apices are preserved, acute, and pointed. ‘The second
example on this same block of stone is smaller and much less perfect,
with portions of six or seven leaves, of which the two most complete
have rounded apices.

The most complete specimen (Pl. XIII, Fig. 2) is on a separate
piece of matrix and displays no less than at least nine leaves or
portions. Here there are certainly two in which the apices are
obtusely rounded, giving to the leaves a more or less elongately
pyriform or club-shaped outline. On a continuation of this same
piece of matrix is a small third cluster in which five leaves are
preserved, all with angular apices, but the apical portions are shorter
than in Pl. XIII, Fig. 1. On the reverse of this specimen of shale
occurs the fourth cluster, which consists of the remains of four, or
perhaps five leaves, also radiate.

The substance of these leaves is thick, coriaceous, and black in
colour, in both examples on the large hand-specimen, whilst the
three on the smaller are matrix impressions with the venation
apparent. ‘These leaves are petiolate, as described by Arber, and in
one of the smaller and less complete examples this petiolate attach-
ment is fairly apparent.

There are now six instances of this radiate arrangement of leaves
in Woeggerathiopsis known, and if Arber’s illustration is of the same
nature (and I have very little doubt it is so), there is then a seventh,
viz. two by Dana, and the four here described in which the leaves
are spread out in a circle, radiate from a common centre, and in each
instance present what, I believe, is the deceptive appearance of being
on the same plane with one another. It is remarkable that, in the
six instances, the mode of preservation is precisely the same.

It is at first difficuit to obliterate from one’s mind the idea of
a verticillate arrangement of these leaves, but if we devote a little
consideration to the phyllotaxis of Cordaites, an explanation of this
radiate arrangement will, I think, be forthcoming, for we must not
lose sight of the strong consensus of opinion that Cordaites and
Noeggerathiopsis, if not identical, are most nearly related, Professor
Seward even saying, in 1907: ‘I prefer to adopt the generic name
Cordaites in preference to that of Moeggerathiopsis on the ground
that Noeggerathiopsis is probably not distinct from the widely
distributed northern type.” ?

1 Seward, Rec. Geol. Surv. India, xxvi, pt. i, p. 60, 1907. The close
affinity of the two genera in question is supported by Zeiller, 1882 (Ann.
Mines, Livr. Sept.-Oct. 1882) ; Schenk, 1890 (Zittel’s Handb. Pal., Abth. ii,
p. 330, footnote) ; Kurtz, 1894 (Revista Museo de la Plata, v, pp. 130-1, 1894) ;
White, 1908 (Com. Hstudos Minas Brazil, Relatorio final, 1908, pt. iii,
p. 546); Krasser, 1909 (Jahrb. Geol. Reichst. Wien, lix, Heft i, p. 121, 1909) ;
Seward, 1907 (Rec. Geol. Surv. India, xxxvi, pt. i, p. 60, 1907); Seward,
1907 (Trans. Geol. Soc. S. Africa, x, p. 707, 1907).

292 R. Htherrdge—Leaves of Noeggerathiopsis.

One of F. C. Grand-Eury’s figures! of Cordaites lingulatus displays

the terminal leaves of a branch bunched together or clustered, and

more or less subimbricate. By exerting downwards an expanding
pressure upon such a clump, when in the fresh state, a star-like
disposition, such as we have presented to us in WVoeggerathiopsis,
would, in all probability, be the result. What appears to be an
improved copy of Grand-Kury’s figure is given by Renault.” A similar
terminal clustering is also visible in the former author’s figure of
Dory- Cordaites.*

If this cluster method of leaf arrangement be admitted in-
Noeggerathiopsis it at once lends support to the accuracy of Zeiller’s
reference to it of certain leaf-bearing branch portions, with leaf-scars
found in the Coal-measures of Tong-Kin. He remarked as follows:
‘‘’empreintes correspondant a de petits fragments de rameaux, et
portant des cicatrices foliaires trés analogues a celles des Cordaicladus,
marquées chacune de plusieurs cicatricules ponctiformes, disposées
les unes a la suite des autres sur un arc paralléle au bord supérieur
de la cicatrice.’’®

No other example of Woeggerathiopsis leaves preserved in this
condition, other than those now recorded, has been found in the
Upper Coal-measures of New South Wales so far as | am aware.
Referring to an occurrence of stems similar to that recorded by Zeiller,
Mr. L. Lesquereux* said ‘‘fragments of ribbon-like leaves rarely
found in connexion with the stems ’’.

The leaves of Cordaites are said by authorities to be spirally

arranged on a branch, but a very strange and remarkable form is
figured by Lesquereux as Cordaites radiatus.° He wrote: ‘‘ Leaves
short, narrow, linear, obtuse, placed in right-angle and star-like
around the stems.” His fig. 5 is ‘‘part of a stem covered by
leaves horizontally diverging, so that each section of the stem shows
them placed exactly like the rays of a star’. Lesquereux’s
expressions are not too clear; does he wish it to be inferred that
the phyllotaxis is verticillate? The figures certainly have such an
appearance. Or, is it an instance of a clump pressed down from
above, as I have suggested to account for the radiate arrangement of
the leaves in Moeggerathiopsis ?

Locality.—¥ig. 1. Mount Kembla, Illawarra. Collected by W. A.
Cuneo. Fig. 2. Mount Kembla. Collected by C. Cullen.

Horizon.—Upper Coal-measures (Permo-Carboniferous).

EXPLANATION OF PLATE XIII.
Leaves of Noeggerathiopsis.
Fic. 1.—Seven leaves radiating from a common centre, lanceolate-spathulate,
four of the more complete with acute apices.
,, 2.—Another example, with at least nine leaves radiate and more
symmetrically arranged than in Fig. 1; two appear to have obtusely
rounded apices.

Renault, Cours Bot. Foss., i, pl. xii, fig. 1, 1881.
Grand-Eury, loc. cit., pl. xviii, fig. 8.
Zeiller, Ann. des Mines, 1882, Sept.—Oct., p. 26 (separate copy).
Lesquereux, Descrip. Coal Flora Carb. Form. Pennsylvania (Second Geol.
Surv. Penn., Report Progress, P), i, p. 525, 1880.

® Lesquereux, loc. cit., p. 540, pl. Ixxxvii, figs. 5, 6.

- o DO

Grou. Mac., 1918. IPAs} UNL,

P. T, Haminond, Sydney, N.S.IW., del. Bale, virnp.
LEAVES OF N@GGEHERATHIOPSIS.

Coat MEASURES. New SourH WALES.

kh. H. Rastall—The Genesis of Tungsten Ores. 293

[ Postseript.—The Australian leaf-clusters figured by Mr. Etheridge
bear a very close resemblance to an Indian specimen reproduced in
vol. i (p. 242, fig. 472) of my Yossil Plants, which shows leaves
attached in a close spiral to a supporting axis.

The late Miss Ruth Holden detected certain differences similar to
those pointed out by Professor Zeiller in the stomatal arrangement
on Noeggerathiopsis leaves from India as compared with that on
English leaves of Cordaites, but the results were not published
(Fossil Plants, vol. iv, pp. 248-4). Mr.Sahni, of Emmanuel College,
Cambridge, who has made a further examination of cuticular
preparations, hopes in the near future to make a contribution to
this subject.—A. C. Sewarp. ]

Il.—Tue Genrsis or Tunesten Orgs.
By R. H. Rastau, M.A., F.G.S.
(Continued from the June Number, p. 246.)

Parr Ill: Scuerrrire Depostrs.

{ROM the descriptions already given, and from a general survey of
|: the literature of the subject, it is apparent that scheelite is
a frequent associate of wolframite in the lodes of magmatic origin.
In fact, a certain number of the occurrences already cited, especially in
the second part of this paper, might almost as well have been described
as scheelite deposits, since the two minerals are found in something
like equal quantities. This applies, for example, to a large number
of the American and Canadian occurrences, to those of the Malay
States, and others. This is only to be expected from general
cousiderations, since gases or solutions containing chemically active
tungsten compounds coming in contact with calcareous material
would naturally tend to form calcium tungstate. The same applies
to lead-bearing minerals; hence in a few instances lead tungstate,
stolzite, has been found in association with scheelite. It is of
interest to note that scheelite often contains from 1 to 3 per cent of
molybdenum. Wolframite and scheelite are often found in lodes and
other masses very closely intergrown, and in many cases there is
evidence of much pseudomorphism. In some cases scheelite has
clearly replaced wolframite, while in other cases the reverse holds.
The law governing the paramorphism of these minerals is somewhat
obscure, and it is not easy to say anything definite on the subject.
In this direction further investigation is required, although the point
is not perhaps of much practical importance.

With regard to the predominance of wolframite or scheelite in any
particular district, the general rule seems to be that wherever the
country rock is more or less calcareous scheelite tends to form; that
this would naturally be so is of course obvious, and the subject
hardly seems to need much further elaboration. ‘The general aspect
of the problem can be more satisfactorily discussed after consideration
of certain deposits in which scheelite is the dominant or even the
only tungsten ore present, since such do occur in various parts of the
world.

294 kh. H. Rastall—The Genesis of Tungsten Ores.

Although scheelite occurs along with wolframite in Cornwall it is
only in small quantity and of no practical importance. The only
workable scheelite deposit known in the British Isles is at Grainsgill
in Cumberland, on the north-eastern side of the Skiddaw area.
Here the lodes are highly mineralized quartz veins connected with
the pneumatolytic phase of the Skiddaw granite; they are in close
association with the greisen of Grainsgill, which is certainly a
differentiation product of the granite magma. Unfortunately a good
deal of uncertainty still exists as to the relation of the lodes to the
surrounding rocks, and especially to the gabbro and granophyre of
- Carrock Fell. ‘This is a very important point in relation to the age

of the latter, which is a matter of dispute. ‘The minerals found in
association with the scheelite ores are molybdenite, arsenopyrite,
pyromorphite, galena, blende, native bismuth, bismuth telluride
(with a little gold), and tourmaline, while crystals of fluorite
have been observed in joint planes in the greisen; it is notable
also that arsenopyrite occurs in considerable quantity in the same
rock. It is not known whether the lead-zinc-bismuth minera!s
are contemporaneous with the quartz and wolfram minerals or
whether they belong to a later phase of mineralization related to the
post-Carboniferous lead-zine deposits of the North of England. The
presence of tourmaline and fluorite indicates pneumatolytic influences,
and in any case the genetic connexion with the Grainsgill greisen
seems clear.’

In Spain and Portugal scheelite is found together with wolframite
in many of the deposits. At the La Sorpresa mine in the province
of Cordoba it occurs in this way in quartz veins, running from
granite into slate, and the ores tend to occur especially at the
junction of the two rocks. his fact appears to bring them into the
category of contact deposits. In a somewhat similar way scheelite
is found in Haute Vienne, France,? in veins with wolframite,
cassiterite, molybdenite, arsenopyrite, and pyrite in a gangue of
quartz. This is an example of its occurrence in the normal tin-
wolfram lode type.

An interesting occurrence of scheelite with cassiterite is found -at
Pitkaranta in Finland, to the north of Lake Ladoga.* Here gneisses
and schists containing beds of limestone are intruded by Rapakiwi
granite, and it is in the limestones that the ores principally occur.
The ores include three principal types: (1) magnetite, (2) copper
ore, and (3) tin-scheelite ore. All the ores are intergrown with
a remarkable variety of contact-metamorphic calcareous minerals,
including diopside, garnet, vesuvianite, chondrodite, and calcite.
Topaz and fluorite have also been observed in small quantity. This
-is a particularly instructive case, since here, where the ores are so
closely associated with limestone, scheelite is found without

' Finlayson, GEoL. Mac., 1910, p. 19. The Mineral Resources of Great

Britain, vol.i: ‘Tungsten and Manganese Ores’’ (Mem. Geol. Surv.),
1916, p. 3.

” Huré, Bull. Soc. Industrie Minérale, vol. ix, p. 99.

* Triistedt, ‘‘Die Erzlagerstatten von Pitkiranta am Ladogasee’’: Bull.

Comm. Geol. Finlande, 1907, No. 19.

kh. H, Rastall—The Genesis of Tungsten Ores. 295

wolframite. The mineralization is clearly pneumatolytic, as shown
by the occurrence of greisen and fluorine-bearing minerals. It is
evident that caleium carbonate was abundant in the country rock and
the tungsten compounds of the intrusive magma combined with the
ealcium rather than withiron; that iron was abundantly present is
proved by the fact that the iron ores are demonstrably older than the
tin ores. ‘This case shows certain affinities with the occurrence at
Trumbull, Connecticut, already referred to at some length. The
ore-deposits at Pitkaranta are certainly of metamorphic origin,
being referable to the intrusion of the Rapakiwi granite, and the
metamorphism is equally clearly of pneumatolytic character; the
action was selective, and the tungsten-bearing vapours or solutions
combined by preference with lime rather than iron.

As before stated, scheelite occurs in many parts of Canada; a good
example is afforded by the scheelite mine near the Moose River gold-
mines in Halifax County, Nova Scotia.! The country rock consists
of highly folded and cleaved quartzites and slates. The veins con-
taining the scheelite are similar to the gold-bearing veins in the
adjoining gold-mines. They contain quartz, felspar, mica, tourmaline,
arsenopyrite, and carbonates (calcite and ankerite). The scheelite is
concentrated mainly at the top of anticlines or in the troughs of
synelines. ‘These mineralized veins are accompanied by -veins of
pure quartz of apparently later date. The mineral veins appear to
be essentially pegmatitic in their nature, as shown by the presence of
felspar and mica. .he non-mineralized quartz veins probably repre-
sent a later differentiate from the same source.

In the Yukon Territory scheelite has been known for some time as
a heavy concentrate obtained in gold-washing, and the mineral has
lately been located in lodes in the neighbourhood of Dublin Gulch.
It occurs in small quartz veins, which themselves intersect zones of
pegmatite within the granite. Wolfram and tinstone also oceur in
small quantities.

At the present time the world’s greatest producer of scheelite is
California. The Atolia mining district, in the Mohave Desert, on
the borders of San Bernardino and Kern Counties, in 1916 shipped
1,831 tons of scheelite concentrates, carrying on an average 60 per
cent of tungsten trioxide. A large part of this ore is obtained from
alluvial deposits, where it is found in lumps up to 100 Ib. in weight,
but it is also worked to a considerable extent in lodes. These lodes
are as a rule more or less continuous fissures in granite, but in some
places they appear to be associated with small basic dykes cutting
the granite, while in other places the scheelite is found in meta-
morphosed limestones at or near the granite contact, associated with
garnet, epidote, and other metamorphic minerals. The lodes proper
consist of scheelite with a gangue of quartz; they run up to 3 feet
in width, and have been followed to a depth of 700 feet. In other
parts of Kern County scheelite occurs in bunches in gold veins, and
as nearly pure stringers cutting through slate; also in veins in
granite with amphibole, pyroxene, garnet, sphene, and oxidized

Report of the Geological Survey of Canada, Department of Mines, for the
year 1916, Ottawa, 1917, p. 249.

296 H. A. Baker—The Pre-Thanetian Erosion

copper minerals, as well as in pegmatites with quartz, oligoclase,
and muscovite.’ The general association of the scheelite deposits of
‘California is with siliceous gold veins in connexion with granites.
This shows a distinct resemblance to the wolfram-gold association of
Boulder County, Colorado, but in California more lime is present in
the rocks, and therefore scheelite has been formed instead of
wolfram.

In the Federated Malay States scheelite occurs in considerable
quantity in addition to wolframite. A particularly interesting case
has been noticed at Salak.? It is a lode about 12 feet wide, con-
sisting of scheelite, quartz, and light-yellow tourmaline, with traces
of arsenic and copper. Another scheelite vein also contained fluorite
and axinite with a little quartz. There are several other instances
of scheelite lodes all apparently more or less closely associated with
granite-limestone contacts, ‘The mineral is also found to a small
extent in the gold veins of the Raub mines, where the country rock
is distinctly calcareous in character.

Summary oF Parr III.

It would be easy to give many more examples of the occurrence of
scheelite in situ in lodes, veins, and contact deposits, but it is
doubtful if any good purpose would be served by so doing. Enough
has been said to show that in very many cases scheelite is found as
a lode mineral either with or without wolframite. It is also
a frequent product of contact metamorphism of granites intruded
into or near limestones. This metamorphism is of the type commonly,
though perhaps unnecessarily, called pneumatolytic. A regular
gradation can be traced from the tin-wolfram deposits, through the
wolfram deposits without tin to the scheelite lodes. This transition
is on the whole accompanied by a falling-off in the amount of the
paragenetic molybdenum and arsenic sulphides and the minerals of
the fluorine-boron group, but in certain instances tourmaline and
fluorite are found to survive into the scheelite lodes. The genetic
connexion between scheelite and siliceous gold veins is also of
significance.

(To be concluded in the next Number.)

TI].—On tee Pre-Tuanetian Erosion oF THE CHALK IN PARTS OF
THE Lonpon Basin.

By HERBERT ARTHUR BAKER, B.Sc., F.G.S.

T has long been recogn'zed that, in early Eocene times, while the
‘‘Caleaire de Mons”’ was being deposited in the Belgian area,
large tracts of the Upper Chalk were removed by denudation from
the south-east of England. The true extent of the unconformity
between the Chalk and our oldest Eocene strata is now to be seen
only where the Eocene cover yet remains. Even where the Chalk is

' The Mineral Industry, vol. xxiv, p. 687, 1916, and vol. xxv, p. 724, 1917;
Mining and Scientific Press, May 27, 1916.
? Scrivenor, loc. cit., p. 7.

of the Chalk in the London Basin. 297

so covered, the unconformity must have been accentuated to some
extent in consequence of the solvent action of percolating carbonated
waters, the evidence of which is familiar to us as ‘‘ pipes”’ in the
Chalk filled with Eocene strata, and the persistent bed of unworn,
green-coated flints (‘‘ Bull-head” Bed) which everywhere occurs
between our lowest Eocenes and the Chalk; but such secondary
action is likely to have been more or less uniform throughout the
whole area beneath the Tertiary cover.

Thanks to the steady accumulation of data concerning well-borings
and the energies of various workers who have given cartographical
expression to the information thus made available, we have now
a good working knowledge of the present contours of the Chalk
surface within the London Basin beneath the Tertiary cover. ‘The
present configuration of this Chalk surface is, of course, widely
different from that which it presented at the time of the deposition
of our oldest Eocenes, in consequence of the tilting and warping
effects of later movements. Nevertheless, in regard to the area
within the immediate vicinity of London, we have some knowledge
of the effects of these post-Cretaceous movements upon the Chalk
formation, since here a number of deep borings have completely
pierced the Chalk, thus affording us information as to the present
level of its base. We are therefore in a position to apply a
‘correction’, so as to reduce the base of the Chalk to a horizontal
plane, and, having done this, to observe the form which the ccntours
of the Chalk surface then take. If the correction be applied so as to
cause the base of the Chalk to occupy a horizontal plane at present sea-
level, the resulting surface-contours are then also the ‘‘isopachytes”’
or lines of equal thickness of the formation.

‘The movement of elevation which set in towards the end of
Cretaceous times and ushered in the Tertiary era appears to haye
been a widespread and regional one, and it is reasonable to assume
that in the area under present consideration the base of the Chalk,
at the beginning of Tertiary times, did not deviate widely from
horizontality. Consequently the contours of the Chalk surface
beneath the Eocene cover, when the base of the formation has been
corrected to horizontality, may fairly be regarded as giving an
approximately true representation of the configuration of the surface
upon which our oldest Eocenes were deposited.

In order to obtain these pre-Thanetian contours of the Chalk
surface we proceed as follows: We first plot upon the map the sites
of the deep borings (seventeen in number) which have completely
pierced the Chalk formation in the area under consideration, inserting
in each case the depth below Ordnance Datum at which the base of
the Chalk occurs. We then draw in the present contours in the
base of the Chalk at intervals of 100 feet, working upon the available
data, and assuming an even gradient between any boring and its
neighbours. ‘he total number of borings not being large, the trend
of the lines is doubtless influenced somewhat unduly by the accidents
of boring sites, but fortunately the sites are fairly evenly distributed
throughout the area, and the error involved is not serious. Having
prepared this map, we superimpose upon it the map of the same area

298 H. A. Baker—The Pre-Thanetran Hrosion

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showing the present contours in the sub-EKocene Chalk surface.?
The first map indicates the amount of correction to be applied to the
base of the Chalk at any point in order to bring it to horizontality at
present sea-level, and the superimposed map is corrected corre-
spondingly. For example, the points at which the O.D. contour
of the superimposed map intersects the —600 contour of the base of

1 In this investigation the writer has used the map of the Pre-Tertiary Chalk
surface prepared by Mr. L. J. Wills (Records of London Wells, Mem. Geol.
Sury., 1913) and also that by Professor P. G. H. Boswell (Q.J.G.S.,
vol. Ixxi, pl. x):

of the Chalk vn the London Basin. 299

the Chalk are points on the 600 contour of the corrected Chalk
surface. Similarly, points at which the —200 contour of the present
Chalk surface intersects the —700 contour of the base of the Chalk
are points on the 500 contour of the corrected surface, and so on. By
joining up the similarly numbered points so obtained, the contour
system of the corrected pre-Tertiary Chalk surface is arrived at
(see Map 1). The numbers appended to the contours possess only
a relative significance. The base of the Chalk might have been
corrected so as to cause it to occupy any horizontal plane, but by
selecting present sea-level as the datum-plane we have the additional
advantage that the lines serve equally well as the isopachytes of the
Chalk formation. _

A glance at the map reveals at once that the information afforded
by it well repays the labour-involved in its preparation. It appears
that the age of the Streatham—Beckton fault is pre-Tertiary, and
from the form of the lines in the neighbourhood of Loughton we
may suspect faulting here also.

The first significant fact which the map brings out with great
clearness is that in pre-Tertiary times the Chalk of this area was
denuded in such a way as to produce escarpments facing inwards
towards the centre of the present London Basin, thus indicating
plainly that the central area experienced a somewhat greater uplift
and suffered greater denudation than the district farther west.
With the exception of a small area between Kentish Town and Mile
End, where the Chalk has probably been protected by faulting, it
is a noteworthy fact that the Chalk is thinnest over the area where
the Gauit beneath it rests directly upon the Paleozoic floor, and the
general character of the pre-Tertiary denudation of the Chalk surface
is in very close sympathy with the contours of the Paleozoic floor
when the latter is corrected for post-Cretaceous movements.

The writer has elsewhere put forward the view that the area under
present consideration lies on the south-easterly prolongation of the
well-known Charnian Axis of Professor P. F. Kendall, and he
inclines to the belief that the character of the pre-Tertiary
denudation of the Chalk here points to the operation of Charnian
posthumous movement in pre-Tertiary times. When we proceed to
investigate the question of the zonal composition of the denuded
Upper Chalk surface further suggestive evidence is forthcoming.
At any rate, additional support is given to the statement made above
that the general character of the pre-Tertiary denudation of the
Chalk surface is closely associated with the pre-Cretaceous form of
the Paleozoic floor.

In endeavouring to insert upon the map the positions of the
boundaries of the zonal outcrops beneath the Eocene cover we are at
once confronted with the difficulty that we have as yet little
knowledge of the thicknesses of the various zones of the Upper
Chalk in and near this area. It has been possible, in the case of
some of the borings, from the details given in the journal, to effect
the division between Lower, Middle, and Upper Chalk, and some-
times horizons easily recognizable lithologically, such as the Melbourn
Rock and the Chalk Rock, can be identified. Apart from this we

300 H, A. Baker—The Pre-Thanetran Erosion

are dependent upon the information forthcoming from workers who

have studied the Chalk of neighbouring districts. It is fairly
certain, however, that except in the west the whole of the sub-
Kocene surface of the area under present consideration is occupied by
_ the outcrop of the thick zone of Dicraster coranguinum. At Crossness
the Chalk proved to be 684 feet thick, but the Chalk exposed to
view in the Woolwich district, not far away, is, to the writer’s
personal knowledge, clearly referable to the Jf. coranguinum zone.
Of the 654 feet of Chalk occurring at Mile End, 259 feet were
assigned to the Upper Chalk, and, since allowance must be made for
the Chalk Rock and the J. cortestudinarium zone, it is not likely
that any higher horizon than that of JL coranguinum occurs here.
Even in the case of the 700 feet of Chalk which occurs between
Kentish Town and Mile End the statement still holds good. If we
take the thicknesses of the Lower and Middle Chalk as recorded at
Mile End, allow only 10 feet for the Chalk Rock and 50 feet for the
zone of I. cortestudinarium, we are left with 225 feet of Chalk, and
it is hardly likely that the I. coranguinum zone is much less than
this in thickness.

Where the Chalk decreases to 500 feet in thickness, as it does
between Loughton and Turnford, the question arises as to whether
the W. cortestudinarium zone there composes the sub-Kocene surface.
At Turnford 406 feet were assigned to the Lower and Middle Chalk
and 15 feet to the Chalk Rock. Allowing 50 feet for the JL cor-
testudinartum zone, we are still left with about 380 feet of
M. coranguinum Chalk. Hence, as already remarked, it is fairly
certain that except in the west the whole of the sub-Eocene Chalk
surface of our area is occupied by the outcrop of IL coranguinum
Chalk.

But in the west a different state of affairs obtains. Here the
Chalk reaches a thickness of as much as 950 feet in the neighbour-
hood of Beaconsfield, and 900 feet a little further south at Taplow.
In this neighbourhood two deep wells have completely pierced the
Chalk, one at Slough and the other at Winkfield. With regard to
the first, beyond the fact that the Chalk was found to have a thick-
ness of 778 ft. 10 in., no further particulars concerning the formation
appear to be available. But in the case of the Winkfield well we
are more fortunately situated. A full account of this has been
published,’ and we are in possession of the information that the
Lower Chalk was 219 feet thick, the Middle Chalk 169 feet, the
Chalk Rock 8 feet, and the Upper Chalk 829 feet. Turning now to
other authorities for information, we find that Mr. H. J. Osborne
White ? suggests 50 feet as the thickness of the JZ. cortestudinarium
zone and 220 feet as that of the JZ. coranguinum zone in this area.
Adopting these figures, we find that at Winkfield we get 666 feet as
the thickness of the Chalk from the base of the formation to the base
of the Marsupites zone, thus leaving 59 feet of Chalk for the latter

1 Water Supply of Berkshire (Mem. Geol. Sury.), 1902, pp. 95-6.

* “Berkshire and Part of the Thames Valley’’: Jub. Vol. Geol. Assoc.,
pt. 1i, 1910.

of the Chalk vm the London Basin. 301

zone here. Again, fortunately we find two other conveniently
situated borings supplying information which can be combined with
these figures. In the well-known deep boring at Richmond Water-
works the Lower Chalk was 220 feet thick, the Middle Chalk
145 feet, the Chalk Rock 5 feet, and the Upper Chalk 300 feet.
Adopting the figure of 50 feet for the thickness of the J. cor-
testudinarium zone, it is further necessary to take a figure for the
thickness of the IL coranguinum zone at Richmond. Bearing in
mind the recorded thickness of 280 feet for this zone further east in
Kent, the writer adopted as a working figure 250 feet for the
thickness of JL. coranguinum Chalk at Richmond. Hence, at the
latter site, the level of 670 feet above the base of the formation, for
the base of the Alarsupites zone, was arrived at. The third boring
site affording information is that at Bushey (Colne Valley Water-
works), where the Lower Chalk was 255 feet thick, the Middle Chalk
267 feet, the Chalk Rock 8 feet, and the Upper Chalk 156 feet. In
the absence of any evidence to the contrary the thicknesses of 50 feet
for the IL cortestudinariwm zone and 220 feet for the AL. coranguinum
zone may be taken, and the level of 800 feet above the base of the
formation for the base of the J/arsupites zone is supplied. Having
now three suitably situated working levels for the base of the
Marsupites zone, and the present map, the plotting of the concealed
boundary between I coranguinum and MMarsupites Chalk becomes
a simple problem in geometry. ‘The result is indicated on the map.
In view of the possibility that the figure taken for the thickness of
M. coranguinum Chalk at Richmond (250 feet) may be a little
excessive, the boundary perhaps lies a httle further south between
Winkfield and Richmond than is represented.

Mr. Osborne White gives 70 feet as the superior limit of thickness
of the Marsupites zone in Berks and Bucks, and the position of the
upper limiting boundary of the zone is inserted on the map in
accordance with this figure. On the assumption of an average
thickness of 25 feet for the Uintacrinus subzone the line of division
of the latter from the Marsupites band can also be inserted.

Field-workers, in referring to the interesting development of
phosphatic Chalk of the Marsupites zone, seen at Taplow, have stated
that it is not improbable that the poorly exposed upper part of the
section belongs to the succeeding zone of Actinocamax quadratus,
although the latter has so far been identified in only two places,
namely, Borough Hill, west of Winterbourne, and Kintbury, both
these places being well to the west of the Taplow-—Beaconsfield
district. Our present map strongly suggests the existence of the
A. quadratus zone in the latter area, and is an interesting incentive
to field-workers in that district. From the figures already adopted
it will be seen that a thickness of 736 feet accounts for the whole of
the Chalk in this area from the base of the formation to the top of
the Marsupites zone, and this after giving to the latter its maximum
thickness of 70 feet. Consequently it follows that in the neighbour-
hood of Beaconsfield there is still a thickness of rather more than
200 feet of Chalk to be accounted for, and hence it appears practically
certain that there the A. guadratus zone possesses a good thickness.

302 H. A. Baker—The Pre-Thanetian Erosion

Future quarrying operations in the neighbourhood should prove
interesting.

To the writer the point of greatest interest was the discovery that,
as the concealed zonal outcrops approach within the sphere of
influence of the ancient Charnian ridge, they suffer an abrupt change
of strike and take on a northerly as well as a westerly trend. The
evidence seems convincing that in this area the belt of maximum
denudation of the Chalk in pre-Thanetian times possessed a
N.W.-S.E. alignment, and this fact must be ascribed either to

Miles.
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the influence exerted by the form of the Paleozoic floor at that time
or else to the operation of Charnian posthumous movement during
the erosion of the Chalk. The area furnishing this evidence of
a tendency on the part of the Chalk zonal outcrops to assume a
N.W.-S.E. alignment is very small, but considering the great extent
to which the erosion of the Chalk has been carried during later
times, the fact that even some evidence of this tendency has been
preserved to us can only be regarded as a fortunate accident.

We are, perhaps, hardly in a position to consider the question of

of the Chalk wn the London Basin. 303

the precise manner in which this pre-Thanetian denudation of the
Chalk was effected, but it appears likely that land existed here in
Montian times and that strike streams ran at the foot of the escarp-
ment, their direction being influenced by the presence of the ridge
which proceeded from west to east by way of Southall and Chiswick.
It is perhaps more than coincidence that the course of the present
Thames shows a tendency to adhere to the same direction.

Interesting light is thrown on the question of the source of the
material composing the Lower Eocenes of the London area. It
seems clear that the material must have come from the east; it can
hardly have been carried from the west over the escarpment. We
have good reason to believe, too, that at this time, to the south of
the present area, the Wealden uplift had already been initiated, and
the interesting question is raised as to whether the denudation
of the Chalk had been carried, by Thanetian times, to an extent
sufficient to expose to eroding influences an adequately large area of
the Lower Greensand to furnish the arenaceous material of the
Lower London Tertiaries.

A simple movement of submergence appears all that is necessary
to explain the overlapping of the Thanet Sand by the Reading Beds
in our area, and with regard to the development of the Lower
London Tertiary Pebble-beds (Blackheath Pebble-beds) in the
Woolwich, Blackheath, and Bromley districts, it appears feasible to
suppose that these accumulated as banks against the easterly
prolongation of the Southall—Chiswick ridge.

In view of the notable scarcity of borings which have completely
pierced the Chalk in Essex, we are very ignorant concerning the
present level of its base in this county and are, in consequence,
unable to adopt the present method of investigation here. In
Suffolk we have more data to work upon, but the area of Chalk yet
remaining beneath the Eocene cover is very limited for our present
purpose. Nevertheless, when the base of the Chalk is corrected to
horizontality, several interesting points are brought out. The Chalk
surface in this county is then seen to slope away east, west, and
south from an area of maximum elevation (over 1,200 feet) situated
between Beccles and Bungay. This area of maximum elevation
extends north-westward to a spot a little east of Norwich, and is
evidently the sole relic of an elevated Chalk area which once
extended much further to the west. In fact, the downward westerly
slope from this district, beneath the Crag deposits, is clearly the
result of post-Eocene and pre-Crag denudation of the Chalk. The
southerly and easterly slopes are, however, facts of deeper significance,
since these are found beneath the area where the Eocene cover yet
remains. There is a drop of 200 feet between Beccles and Aldeburgh
(which is only another way of saying that the Chalk is 200 feet
thicker in the former place than in the latter), and hence we haye in
this area the last remaining evidence of the escarpment (now become
very gently sloping although more elevated) which faced south-
eastward and stretched away many miles to the west and south.
The easterly slope of the corrected Chalk surface from Beccles to
Lowestoft (or thinning of the Chalk formation in that direction) is

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304 H. A. Baker—Pre-Thanetian Erosion, London Basin.

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J.T. Jutson—Interpretation of Dry Lakes. 305

a fact that might have been somewhat surprising if we had not been
partially prepared for it. The Chalkis about 150 feet thicker at
Beccles than at Lowestoft. The present writer has endeavoured to
show elsewhere that this area has been affected by posthumous
movements of an ancient axis which he considers to run parallel
with Kendall’s Charnian Axis, eastward of Kent, into North France.
We notice here what we are also apparently able to detect in the
London area (see section), that during the deposition of the Chalk
(and possibly to some extent during the deposition of the Gault)
there was a definite movement of depression along the line of the old .
axis whereby a somewhat greater thickness of sediment accumulated
vertically above them than elsewhere. Lowestoft lies somewhat to
the east of the line of the easterly axis and hence the decrease in
thickness of the Chalk is accounted for. On this view it follows that
a great thickness of Chalk must have been removed by denudation
from the district to the north-west of Norwich, since over 1,350 feet
of the formation yet remains beneath the Eocene in the neighbour-
hood of Mundesley and Happisburgh.

With regard to the zonal outcrops of the Chalk beneath the
Eocene cover in Suffolk and Essex, the Ostrea lunata zone evidently
does not occur here, but the line of separation of the Belemnitella
mucronata and Actinocamax quadratus zones probably runs from
south-east to north-west beneath the Suffolk Kocenes, meeting the
coast somewhere in the neighbourhood of Harwich. After emerging
from beneath the Eocenes westward of Bramford the boundary turns
sharply to the north as the result of later denudation. The boundary
between the A. guadratus and Marsupites zones occurs a little to the
west of Hadleigh, and, beneath the Eocenes, probably sweeps off
to the south-west. The same may be said of the boundary between
the Marsupites and ML. coranguinum zones, which occurs a little to
the west of Sudbury.

In conclusion, it may be remarked that when the Chalk of Essex
comes to be better known it will probably be found to be affected by
a great fault stretching across the whole county from the neighbour-
hood of Cliffe, in Kent, to near Dunmow and Thaxted, as a result
of which Chalk of the J/arsupites zone, on the eastern side, is placed
in juxtaposition with the MZ. coranguinum zone on the western side.

The section accompanying the present paper is drawn from the
data suppled by maps showing contours on the Paleozoic floor, in
the base of the Gault, and the base of the Chalk, prepared by the

writer at various times.

ITV.—On rue Occurrence AND INreRPRETATION OF Rock-CLiFFs AND
Rock-F1Loors on THE WesteRN SuHores oF THE ‘‘ Dry” Lakes IN
Soura-CrntrRAL WersTERN AUSTRALIA.

By J. T. JuTSoNn, Geological Survey of Western Australia, Perth.
Inrropucrion.
N South-Central Western Australia, in the physiographic division
which the writer! has termed the Central or Salt Lake Division,
in a large portion of which the average annual rainfall is about
1 “An Outline of the Physiographical Geology (Physiography) of Western
Australia ’’: Bull. 61, Geol. Surv. W. Australia, Perth, 1914, p. 52.
DECADE VI.—VOL. V.—NO. VII. 20

306 J. T. Jutson—Interpretation of the Dry Lakes
10 inches per annum, numerous ‘‘dry” lakes or playas occur.’
These have been described and the question of their origin has been
‘discussed by various authors.2 They have been differently regarded
as due to glacial, marine, and wind action; also as the remains of
old Tertiary rivers now largely obliterated by drifting sands; and
also (in part) as deformation basins. Most writers agree that they
have been formed under subaerial conditions, and probably most
will ultimately agree that deformation is responsible for some at
least of the lakes, or has aided in their formation.

The theory of a migration of the lakes has also been advanced by
the present writer.

Like most other land forms the lake will probably, by further
research, be shown to be due to no single cause, but to a combination
of agents of different relative importance.

SUMMARY.

This paper describes certain features of the ‘‘ dry” lakes in South-
Central Western Australia. These features, which repeatedly occur
over a wide area, indicate, in the writer’s opinion, that the lakes are
migrating westward; and that wind erosion is playing the dominant
part in such migration, and consequently in the present forms and
position of the lakes. Such features are the presence of rock-clifis
and rock-floors on the western, north-western, south-western, and,
to a less extent, on the northern sides of the lakes; and the absence
of such cliffs and floors on the eastern, south-eastern, north-eastern,
and southern sides of the lakes, the place of such cliffs and floors
being taken by sand dunes, sand plains, and silts. The facts set forth
are regarded as confirming, to some extent, the idea of the late
H. P. Woodward that the ‘‘dry”’ lakes are due to wind action.®

1 Salts are precipitated on the lake floors on the evaporation of the transient
thin sheets of water, but so far as the writer is aware there is no thickness of
salt on any of the lakes. The terms ‘‘salt lakes’’ and ‘‘salt lake division ”’
are therefore misnomers. ‘‘ Dry lakes’’ or ‘‘ playas’’ more suitably indicate
the character of the lakes, but as the latter are frequently connected with one
another by defined or ill-defined channels, and as many undoubtedly lie along
the main drainage lines of the country, the writer has suggested the term
‘‘stream-lake system’’ for this dual capacity of portions of the drainage
system. The terms ‘“‘salt lakes’’ and ‘‘dry lakes’’ have become so firmly
rooted in local usage that they will probably remain. It is difficult to suggest
a suitable name for the physiographic division instead of “‘ salt lake division’’.
‘“Dry lake or central division’’ would perhaps be the least objectionable
of any.

2 As to various theories, see J. W. Gregory, “‘The Lake System of
Westralia,’? Geog. Journ., June, 1914, pp. 656-64, map. See also C. G.
Gibson, Bull. 37, Geol. Surv. W. Austral., 1909, p. 12, and Bull. 42, Geol.
Surv. W. Austral., 1912, pp. 11, 12; J. T. Jutson, op. cit., pp. 138-58,
and also Geog. Journ., December, 1917, pp. 418-37, map, figures; A.
Montgomery, Journ. Roy. Soc. W. Austral., vol. ii, pp. 59-96, map, 1915-16;
J. W. Gregory, Geog. Journ., October, 1916, pp. 826-31; and C. 8S. Honman,
Bull. 71, Geol. Surv. W. Austral., 1917, p. 144, and Bull. 73, Geol. Surv.
W. Austral., 1917, p. 17.

° GEOL. MAG., August, 1897, pp. 363-6.

an South-Central Western Australia. . 307

Move or Occurrence or THe Rock-Cuirrs anp Froors, anp
AssociateD Frarures. (Map I.)
The lakes are generally long in proportion to their width, so that
when their trend is referred to it is intended to indicate the direction
of the lake along its ‘‘length”. The trend of different lakes may be

a s f ue Tak s
é 6 L_EQNCRA

e
Xe

20° ComerVatse( PilGoongan Le W\<
QCYCARRIE® Z 1
i L. Gordon

a By j

eKanowna

i fi
boca sa le , Me ee ie
ot VeSea Gree ert ces ; AG L.Yindar lgenda
of Coo. garde e S5) caer te i
Vv é a

0 “ve
a Sourseen (‘oss yw or [2 Lefroy.

4
Aan i \
eds

Sournern Ocean

Seale of Mifes

Q

Map I.—Showing the principal ‘‘ dry’ lakes in South-Central
Western Australia.

308 J.T. Jutson—Interpretation of the Dry Lakes

in almost any direction. Many vary from approximately north and
south, through north-north-west, north-west, to west-north-west.
Some trend north-easterly, and others are approximately east and
west. Probably, however, in the main there is an approximation to
north and south with variations to the east and to the west of north
respectively. When the term ‘“‘ western shore’’ or ‘‘ western side”
is used in this paper, it is meant to include not only the true
western shore when the lake trends approximately north and south,
but also the south-western or north-western shore when the lake
trends north-west or north-east respectively, because the remarks
below as to rock-floors and cliffs apply to the westerly shores as a
whole, despite the defiection of the trend of the lakes from north
and south.

Along the western shores of many, and along the northern shores
of some, of the lakes, rock-cliffs and rock-floors occur. The eastern
and southern shores are usually destitute of these features, which
are replaced by silt floors, sand dunes, and sand plains.

The cliffs are rocky, generally steep, and frequently form very
prominent features in the landscape, when they project as a series of
bold headlands into the lake. So far as known, the commonest
rocks forming the cliffs are what may be called ‘‘greenstones’’,
a field term which includes many kinds of basic igneous rocks,
which, however, need not be enumerated here. Cliffs are also
formed of ‘‘jaspers’’ (quartz hematite schists) and granites. At the
base of the cliffs rock floors of similar or associated rocks frequently
occur. These floors are of such smoothness that the writer has
termed them ‘‘billiard-table rock-floors’”. They may be visible
outward from the base of the cliffs only for a chain or two or they
may extend for hundreds of yards up to a mile or more. Such
floors tend to be covered by the fine silts of the lake, and as these
silts vary in thickness and superficial area (although little is yet
known as regards their thickness), the extent of the floors exposed
also varies.

The rocky cliffs are being worn away by various agents of erosion,
the nature of which is described when discussing the meaning of the
rock-cliffs and floors.

Some lakes may have no rock-cliffs on any side, but the writer is
not aware of any with cliffs on the eastern side. It is possible that
such last-mentioned cliffs nevertheless do occur, but if so they must
be rare.

Small valleys may enter lakes, and the lower portions of such
valleys may, by lateral erosion, become arms of the lakes.

EXAMPLES OF LAKES WITH THE FEATURES DESCRIBED IN SourH-
CentraL Western AvsrraLia. (Map I.)

Kurrawang Lakes, south of the railway line between Kalgoorlie
and Coolgardie. According to C.S. Honman’s maps and descriptions '
the lakes are bounded on the west and north by rock-cliffs, and on

1 Bull. 56, Geol. Surv. W. Austral., 1914, pls. i, ii, fig. 1, pp. 10-12, 34.

in South-Central Western Australia. 309

the south and east by sand plains and sand dunes. The prevailing
wind is stated to be north-westerly.?

Hannan's Lake, south-east of Kalgoorlie. Honman’s maps and
descriptions” show that rock-cliffs and rock-floors occur on the
western shore of the lake, and sand dunes and sand plains on the
southern and south-eastern shores, the material forming the dunes
and plains being blown from the north-west. Honman also refers
(p. 36) to the migration of the lake to the north-west owing to this
removal of material.

Lakes Carey, Raeside, Rebecca, and Goongarrie.—These lakes form
a remarkable group. ‘hey all lie to the east of the railway line
running north from Kalgoorlie to Leonora, Lake Carey being the
most easterly and Lake Goongarrie the most westerly. Lakes Carey,
Raeside, and Rebecca have been mapped and described by Honman,
who states* that they all run north-west and south-east; that all
have escarpments and rock-floors on the western sides and sand dunes
on the eastern; that the rock flooring on the western side is probably
due to migration; and that the fact that the rock-flooring is on the
western side in the case of every lake in the district is probably due
to the prevailing direction of the wind being from the south-west.‘
The writer can confirm from personal observation the occurrence of
rock-cliffs and floors on the western side of Lake Raeside and their
absence, in the areas seen by him, on the eastern. The writer's
observations in regard to Lake Goongarrie, which trends north and
south, show that rock-cliffs and rock-floors occur on the western
side, and sand plains and sand dunes on the eastern. The dominant
winds appear to be westerly. Another moderately large lake, west
of Lake Goongarrie and of the railway line, has not been examined
by the writer.

Lakes north of Southern Cross.—T. Blatchford® points out that
wind-blown deposits occur on the southern or south-eastern edges of
the lakes, the northern and western shores being usually more or less
precipitous with bare rock-floors or covered with very thin deposits.
He concludes that the lakes are migrating westward, and from his
remarks the prevailing winds are probably north-westerly.

The Johnson Lakes, Bremer Range. Honman‘® in referring to these
lakes states that on the north-western side are found hard rock
outerops and cliffs, and on the south-eastern blown sand and gypsum,
forming wide sandy slopes and dunes, due to wind action.

Oya, Chins 10s AL saver, Ale
2 Bull. 66, Geol. Surv. W. Austral., 1916, pl. i, pp. 11, 36.
3 Bull. 73, Geol. Surv. W. Austral., 1917, pp. 17-19.
It might here be noted that Honman accepts J. W. Gregory’s theory on the
lakes asa whole as dismembered river systems. See Bull. 71, 1917, p. 144,
and Bull. 73, 1917, p. 17, Geol. Surv. W. Australia. He also notes (Bull. 71,
p. 15) that Lakes Carey, Raeside, and Rebecca cross the strike of the rocks,
and suggests that these lakes may belong to a different cycle of erosion un-
influenced by geological structure. On the ancient river theory, it could be
contended in explanation of this feature that the old streams were superposed.
The question cannot be discussed here. It will be dealt with elsewhere.

° Bull. 71, Geol. Surv. W. Austral., 1917, pp. 23, 24.

§ Bull. 59, Geol. Surv. W. Austral., 1914, p. 195.

4

310 J.T. Jutson—Interpretation of the Dry Lakes

WeEsTEAN
AUSTRALIA

NORTHERN
| JERRITORY,

o LEONORA

eAALGOORLIE

Sours Ausrraual

FC OM or One

( . * Rocky country,
Sat in places high
. and rermnaled

by steep clhiths.
os Sand ridges}

and sand plains

ABCD tne
of Section

Fig.3 ak
Hf Bedrock == Silts 33: Sands.

Map II.—Iig. 1: Locality map of the southern portion of Western
Australia. Fig. 2: Generalized plan of a ‘‘ dry’? lake with rock-
cliffs and rock-floor. Fig. 3: Diagrammatic section across a
“dry ’’ lake from west to east, showing (A) the rock-cliffs and
rock-floor (B) on the western side, fine silts (c) towards the eastern
side, and blown sands (D) encroaching on the eastern margin of
the lake.

an South-Central Western Australia. all

Lake Cowan, Norseman. W. D, Campbell’s maps and descriptions '
of this lake clearly show that rock-cliffs exist on the western shore
and blown sands on the eastern.

Lake Barlee—H. W. B. Talbot’s maps*® show this lake to be star-
shaped; but where north and south trending portions of the lake
abut rock ridges, the latter are on the western shore of the lake.

Lake Gordon, near Kanowna. This lake has rocky cliffs on the
western shore and sands on the eastern, as personally observed by
the writer.

Mranine oF THE PHENOMENA DESCRIBED.

The facts stated above appear to decisively indicate that the
occurrence of rock-cliffs and rock-floors on the western sides of
“dry” lakes, and their absence on the eastern sides (with replace-
ment on such eastern sides by sand and silt), are not merely
coincidences. There must be some agent now or formerly operating
with dominant power over wide areas in order to produce such
remarkable uniformity of conditions. Such power seems to be
restricted either to marine erosion, or to erosion by terrestrial waters,
or to wind erosion. These possibilities are now considered.

Marine erosion does not seem to apply, for reasons that will be
briefly stated. (1) No evidence has been adduced that the country
has been recently submerged beneath the ocean farther north than
Norseman,’ which is about 129 miles north from the southern coast
of Australia. This distance, however, is short in comparison with
the north and south length of the belt occupied by the ‘‘ dry”’ lakes.
(2) The marine theory claims that the forms of the cliffs are due to
marine erosion. It therefore assumes that these cliffs have practically
sustained no erosion since their supposed emergence from the sea;
an assumption the validity of which is at once questioned owing to,
the fact that normal subaerial erosion—apparently to a considerable
extent—has taken place near the coast since the last undoubted
emergence from the sea of the coastal lands, and consequently
subaerial erosion farther inland must have also occurred. (3) The
effect of present erosional processes is ignored. (4) As there are
long sub-parallel lines of cliffs forming the western shores of lakes,
such cliffs, on the theory of marine erosion, could only be produced
by many distinct uplifts, with pauses long enough to allow the lines
of cliffs to be successfully eroded. This means that the country
should rise by a series of marine-cut very wide benches one above
another, a state that, so far as all knowledge of the country goes,
does not exist. Moreover, as the cliffs face the east, the emergence,
on such theory, must have been from west to east, that is, away
from the present western coastline, the last land to emerge being

Bull. 21, Geol. Surv. W. Austral., 1906, p. 21, and plate.

Bull. 45, Geol. Surv. W. Austral., 1912, pls. i, il.

Well to the east of Norseman the sea in probably Miocene times was much
farther north, but this formerly sea-coyered land is outside the area discussed
in this paper.

1
2
2
3

312 J.T. Jutson—Interpretation of the Dry Lakes

towards the South Australian border. Again, no evidence of this
has been adduced.

Krosion by terrestrial waters, either by river or lake, seems also-
inadequate to explain the facts. Fluviatile action cannot be con-
ceived to produce such forms in their present positions. Former
deep permanent lakes could produce cliffs, but such cliffs would not.
be restricted to practically one side only, nor, stating the matter in
another way, would the high belts of country be bounded by lakes,
and the rock-cliffs of such lakes, on mostly one side only. Further-
more, there is at present no evidence available that such deep
permanent Jakes ever existed. Lacustrine deposits, with abundant
fossils, should occur, but so far they have not been discovered, apart
from the leaves in a deep alluvial deposit at Coolgardie. Rock
benches are characteristic marks of former deep permanent lakes, but
none has ever been found.! With regard to the action of the present
lake waters, as they remain for such a short period and, so far as
observed by the writer, are only a few inches deep at the margin,
abrasion by such waters seem out of the question, although there is
probably some removal of fine detritus from the base of the cliffs by
the lapping of the transient waters. Moreover, the objection as to
abrasion on practically one side only, also applies to the present lake
waters.

There remains, then, but wind erosion, and this most satisfactorily
explains the facts as at present known. It is not claimed that wind
erosion alone is competent to produce the cliffs and rock-floors, and
to cause the lakes to migrate. The subaerial agents of erosion,
comprising insolation, ‘‘exsudation,”’ the beating action of rain, and
general atmospheric weathering, are wearing down the cliffs and
rock-floors, and the gentle lapping of the lake waters may remove
some of the detritus. The wind, however, seems to be the
dominating agent, partly by corrasion, but chiefly by deflation.
The debris is swept away from the cliffs, thus allowing their further
destruction, and the billiard-table floors are produced. Sand is
carried around or across the lake by the wind and deposited on the
eastern and other sides. This, aided by the deposition of fine silt
on the lake floor, forces the water westward, thus assisting to bring
about its migration. In the course of such migration higher rock
belts are met, cliffs formed, and then gradually worn back. Hence
rock-cliffs and rock-floors occur on the western sides, and sands on
the eastern.

If migration has occurred to any extent, and if such migration is
chiefly due to wind erosion, then, without regard to other consider-
ations, the lakes are undoubtedly, in part at least, deflation lakes.

' It is not contended that larger lakes never existed. They have possibly
done so, but there is no available evidence that they formed deep permanent
lakes. What evidence there is points, in some instances, to wider areas of
shallow ephemeral lakes or playas practically similar to those now in existence,
and to the probability that such greater lakes have, owing to local conditions,
shrunk. In other instances the migration of a lake may account for an
apparently greater former lake of the playa type.

in South-Central Western Australia. Ss

This conclusion thus bears out, to some extent at least, Woodward’s
original idea that such lakes are due to wind action.

In their general trend, the lakes lie along drainage lines—more or
less dismembered and probably in part deformed—which have been
formed under existing conditions or have belonged to an old river
system when the climate was moister and perhaps the country lower
than at present, as suggested by Gibson and J. W. Gregory. That
they are the remains of an ancient river system formed under
different climatic conditions than those of to-day has not yet been
demonstrated ; but if it were, such demonstration would not, in the
writer’s opinion, invalidate the conclusion that portions at least
of the lakes and the striking characteristics, the subject of this paper,
are dominantly due to wind erosion.

_Few observations have as yet been recorded as to the dominant
direction of the wind, but from the writer’s personal, although
limited, observations in the Comet Vale—Goongarrie district, made
since writing his physiography of Western Australia, and the paper
referred to above in the Geographical Journal, it may be said that
although there is perhaps no prevailing wind, yet the dominant wind
appears to be from the west (north-west, west, or south-west). As
shown above, Honman and Blatchford also hold that the dominant
wind is from the same quarter.

Woodward! has noted the retarding effect of the ground-water
table on wind erosion on lake-floors, and this feature may help to
explain the very even surfaces of the billiard-table rock- floors, the
wind receiving at least a temporary check on reaching the more or
less saturated zone. Honman? also believes that during lake
migration the rock-floor is kept level by moisture. The silts of the
lakes are always moist, except perhaps, at times, the actual surface
film. A moist surface, in addition to preventing the removal of
material, may also, as pointed out by A. W. Grabau, with regard to
the American playas,’ catch dust particles carried across the surface
by the winds, and by this means the thickness of the deposits may be
increased. Hence the silts of the eastern portions of the ‘‘dry”
lakes may be partly wind-blown, and not entirely due to deposition
under water, this wind-blown material being probably derived from
the western areas.‘ If such wind transportation does take place it
shows that, despite its retarding effect, the hygroscopic character of
the silt is not an absolute bar to wind transportation, probably
because the actual surface may (at various times at least) be
sufficiently dry to allow such transportation. In any event, however,
from the facts set out in this paper, it seems clear that the wind can
and does remove material from the western sides of the ‘‘dry”’ lakes.

1 Op. cit., p. 365.

* Bull. 66, Geol. Surv. W. Austral., 1916, p. 36.

* Principles of Stratigraphy, New York, 1913, p. 603.

* Dust is no doubt also caught by the lake waters when they are in
existence, and this is then deposited as an aqueous sediment.

314 Dr. F; R. Cowper Reed—The genus Homalonotus.

V.—Nores on THE GENUS HOMALONOTUS.
By F. R. CowPEr REED, Sc.D., F.G.S..
(Concluded from the June Number, p. 276.)

6. Burmeisteria, Salter, 1865.

(J\HE type of this section is the Lower Devonian species Homalonotus
Herschelt (Murchison)! from South Africa and the Falkland
Isles.? The characters of the section were stated by Salter to be as
follows: ‘‘ Elongate, convex; head triangular, eyes approximate on
gibbous cheeks. Glabella distinct, lobeless, spinous. Thorax slightly
lobed and spinous, as is also the many-ribbed pointed tail.” It
should at once be stated that the type-species has neither a lobeless
nor a spinous glabella, and Salter apparently added in these characters
from the Rhenish H. armatus, Burm., which he included in the
section. The only British form quoted by Salter is one from Devon-
shire based on a pygidium which does not conform to the above
definition and was described under the name WZ. elongatus.*
Woodward,t in reviewing the Devonian species of Womalonotus,
follows Salter in including the latter species in Burmeisteria. .

The course of the facial sutures in H. Herschel: is important; they
bend in rather suddenly in front, so as to form a transverse, gently
arched or sinuated commissure and meet in the middle at a very
obtuse angle. The pre-glabellar area is large, but the pre-sutural
area is very narrow, as in H. Knightiv. The parallel epistomal
sutures arise nearly at right angles to the transverse commissure,
and cross over the margin to the inferior surface. The epistome itself
has a median apiculus projecting in front of the margin of the head-
shield, which is otherwise subtruncate. Lake’s species H. colossus,°
also from the Bokkeveld Beds of South Africa, is represented as
possessing a similar epistomal projection, and in the Brazilian
species /7Z. noticus, Clarke,® it is also developed.

It can hardly be doubted that Salter included more than one
species of Homalonotus under the one specific name H. Herscheli,
though Clarke (op. cit.) seems inclined to question it. Lake (op.
cit.) and Schwarz’ have established several new closely allied species
from the same South African beds, and an examination of Salter’s
original types, now in the British Museum, has convinced me that
H, Herscheli admits of division. The typical form is shown by the
head-shield (No. 11276) illustrated in his figure la, 6, ¢; this
specimen comes from the locality Leo Hoek and has a transverse
shape, a distinctly lobed glabella, and no coarse tubercles or spines on
the surface, except two or three small ones on the pleuro-occipital
ring, the general surface of the head-shield being merely ornamented
with almost equidistant, widely spaced, coarse granules. The facial
Salter, Trans. Geol. Soc., ser. 11, vol. vii, p. 215, pl. xxiv, figs. 1-7, 1856.
Clarke, Hoss. Dev. Parana, 1913, p. 93, pl. iii, figs. 1-4.

Salter, Mon. Brit. Trilob., p. 122, pl. x, figs. 1-2.

Woodward, GEOL. MAG., Dec. IV, Vol. X, p. 29, 1903.

Lake, Ann. S. African Mus., vol. iv, pt. iv, p. 216, pl. xxvi, fig. 1, 1904.
Clarke, op. cit., p. 89, pl. i; pl. ii, figs. 1-13.

Schwarz, Rec. Albany Mus. S. Africa, vol. i, No. vi, pp. 382-91, 1906.

a &- © bo

a

~1

Dr. F. R. Cowper Reed—The genus Homalonotus. 315

sutures cut the lateral borders in front of the genal angles; the
paraglabellar areas are sunken and circumscribed. The pygidium
having the same ornamentation is No. 11282, figs. 7a—d, from the
same locality; this has an interrupted median row of tubercles on
the axial rings, with a lateral row of rather larger ones on each side ;
there are only about half a dozen small tubercles, rather irregularly
disposed, on the lateral lobes. The head-shield represented in Salter’s
figure 2 (No. 11277) has the shape of Schwarz’s H. hippocampus,}
but is rather poorly preserved on the upper surface; it is certainly
more elongated and triangular than No. 11276, though from the
same locality. The large head-shield (No. 11278) from Warm
Bokkeveld outlined by Salter in his fig. 3 is crushed and imperfect,
but the presence of a distinct large tubercle on each side of the
glabella on the faint basal lobes is sufficient to separate it. Perhaps
it belongs to Lake’s H, quernus.?

With regard to Salter’s figured specimens, illustrated by his
figures 4, 5, 6, 8, we can merely say here that none of them agree
with the types of H. Herscheli in ornamentation or characters, but
they suggest a comparison with Schwarz’s species H. horridus?*
and H. agrestis.4

Salter included the European Devonian species H. armatus,
Burm.,° in his section Burmersterva, but the anterior end of the head-
shield has never been fully described or figured, and so far as we
know the truncate edge of the middle-shield corresponds with the
ulmost straight course of the transverse commissure of the facial
sutures. In the allied Z. rhenanus, Koch,® the anterior edge is
slightly- concave and the lateral angles project in front, so that
Giirich has chosen the name Digonus for this group (see below).

The thorax in all the South African forms ascribed to H. Herschel
is obscurely trilobed, and the axis is very wide. The pygidium is
always triangular and produced behind into a point; the segmenta-
tion is more or less distinct and the joints are numerous. The
presence of spines on various parts of the body cannot be regarded as
of primary importance, in spite of Salter’s opinion, and in the type-
specimens of 7. Herscheli they are either inconspicuous or absent.

Apparently it was mainly because of the presence of spines that
Salter included the species H. elongatus, Salt., and H. pradoanus,
De Vern.,’ in his list of members of Burmeisteria. But in both of
these the pygidium is rounded behind and not acuminate. The first
species, H. elongatus, belongs to the same group as H. Champernownet,
Woodw.,® from Devonshire, and a new species, H. bifurcatus, Reed
MS., from the same locality, of which the description awaits

1 Schwarz, op. cit., p. 388, pl. ix, figs. 5a, b.
? Lake, op. cit., p. 216, pl. xxvii, fig. 1.
* Schwarz, op. cit., p. 385, pl. ix, figs. la-c.
+ Ibid., p. 386, pl. ix, figs. 2a, b.
> Koch, op. cit., p. 12, pl. i, figs. 1-6.
6 Thid., p. 32, pl. iii, figs. 1-6.
“ De Verneuil, Bull. Soc. Géol. France, ser. WU, vol. vii, p. 168, pl. iii,
figs. 4a, b, 1850.
8 Woodward, GEoL. MaG., Dec. II, Vol. VIII, p. 489, Pl. XIII, 1881.

‘

316 Dr. F. R. Cowper Reed—The genus Homalonotus.

publication, must also be ascribed to it. The well-marked triloba-
tion of the body, the narrow and distinctly defined axis, and certain
_ features of the head-shield (see below under Burmeisterella), as well
as the oval or semicircular pygidium, mark off this group from the
true H. Herscheli. ‘The pointed pygidium referred by Woodward !
to H. Champernownet on a subsequent occasion seems to belong to
Giirich’s group Digonus and is certainly in no way related to
LH. elongatus.

With #. pradoanus we must associate H. Gervillet, De Vern.,? and
HT, Barratti, Woodw., the latter from Cornwall. The pygidium has
a rounded semi-oval shape, a more or less distinct border, but no
acuminate extremity. The axis in both the thorax and pygidium is
only faintly marked. The head-shield as seen in H. Gervillet, which
is the best-known member of the group, has distinctive features (see
below under Parahomalonotus). ‘The surface is ornamented with
coarse granules and tubercles, but not spines. H. Gervilled was first
described from the Devonian of the Bosphorus, but was more fully
described and figured by Bayle (op. cit.) from the Caleaire de Néhou,
Manche, France. Another allied French species, H. Hausmanni,
Rouault,* must be included in this group of species.

Thus, in addition to the H. Herscheli group (which is the true type
of Burmeisteria), we find three other groups, i.e. (1) the A. rhenanus
(=Digonus, Giirich) group, and also the more distinctly marked
groups of (2) H. elongatus and (8) of H. Gervillei, all developed in
Devonian times and sometimes all included by paleontologists in
Burmeisteria.

7. Calymenella, Bergeron, 1890.

Bergeron® established this genus in 1890 with a new species,
C. Boisseli, Bergeron, from the Ordovician of Hérault, as its type,
and he also included in it the species Calymene Bayani, De Trom. et
Lebese.® The characteristics of the genus were given as follows:
““Glabelle peu bombée, arrondie en avant, portant trois sillons, dont
les deux derniers sont bien visibles; le postérieur s’infléchit en
arriére. Lobes peu accusés. Joues fixes larges. Limbe trés
développé en avant de la glabelle et pouvant se terminer. en
pointe. Pygidium de Calymene.”’ .The facial sutures are believed
to cut the lateral margin behind, but it is not clear if they unite in
front on the upper surface of the head at the base of the rostrum.
It seems, however, that such may possibly have been the case,
judging from some of Bergeron’s figures, and this would explain the
absence of the rostrum from some of the specimens of the middle
shield. The free cheeks are unknown.

As Pompecki’ has remarked, we may probably regard Calymenella

alibi. Wolk DX ip. 157, Pie live Hig.3, 18e2.

2 Bayle, Explic. Carte Géol. France, iv, pl. ii, figs. 1, 3, 6, 1878.

* Woodward, Grou. MaG., Dec. IV, Vol. X, p. 28, woodeut, 1903.

* Rouault, Bull. Soc. Géol. France, ser. II, vol. viii, p. 379, woodcut, 1851.

Pe ae Bull. Soc. Géol. France, ser. III, vol. xviii, p. 365, pl. v, figs. 1-7,
18

° De Tromelin & Lebesconte, Bull. Soc. Géol. France, ser. II, vol. iv,
p. 599, 1875 ; Bergeron, op. cit., pl. v, figs. 8-13.

q Pompecki, Neues Jahrb. f. Min. Geol., Bd. i, p. 241, 1898.

Dr. F. R. Cowper Reed—The genus Homalonotus. 317

as a subgenus of Homalonotus, but it is at any rate an early and
aberrant form. Apart from the presence of the rostrum, it seems
allied to the Grés de May species of this genus, rather than to any
species of Calymene. A rostrum is developed in more than one genus,
and Ampyxz and Probolium are instances. Vogdes' would apparently
refer his species Calymene rostrata, from the Clinton Formation, to
this group or genus Calymenella, but it has a typically lobed glabella
like Calymene, and the facial sutures cut the anterior margin on each
side of the base of the rostrum, which is a triangular projection of
the border, and therefore is structurally distinct.

8. Digonus, Giirich, 1909.

The type-species chosen by Gtirich is Hl. gigas, Roemer,’ and
Giirich’s*® definition of the subgenus may be rendered as follows:
Middle-shield truncate or concave anteriorly, so that the front
margin is biangulated; glabella subquadrate; pygidium with
pointed extremity. The section is characteristic of the Lower
Devonian, and includes a large number of Continental species, of
which Gurich mentions H. scabrosus, Koch,* and H. rhenanus, Koch.®
We may add to Giirich’s definition the fact of the distinct segmenta-
tion of the pygidium, which separates these European Lower
Devonian species from Dipleura, as Kayser pointed out in a footnote
to Koch’s memoir (op. cit., p. 10). Perhaps the British species
Hf. goniopygeus, Woodw.,° belongs to this group, as the pygidium,
which alone is known, agrees with Giirich’s type in general
characters.

The truncate straight or concave anterior end of the middle-
shield in the type-forms corresponds to the course of the transverse
commissure of the facial sutures, and the peculiar course of this
commissure seems to mark off this group of species from the
H. Herscheli group, which they resemble as far as the pygidium is
concerned. In none of them is the true anterior margin of the head-
shield known, so that we are ignorant if the epistome projects in
front or if there is a wide pre-sutural area. For these reasons they
may be regarded as distinct from the typical Burmeisterva group, and
they seem worthy of complete separation from it.

9. Schizopyge, Clarke, 1918.

Clarke’ suggested this name for the aberrant species H. longi-
caudatus, d’Archiac, Fischer, and de Verneuil,’ of the Lower
Devonian of Constantinople, and the two Brazilian species,

1 Vogdes, Amer. Journ. Sci., ser. UI, vol. xxiii, p. 475, 1879; id., Proc.
Acad. Nat. Sci. Philad., 1880, p. 176, figs. 1, 2; id., Bibliogr. Palsesoz: Crust.
{Occas. Papers Calif. Acad. Sci., iv, 1893, p. 223).

* Roemer, Verstein. Harzgeb., t. xi, p. 39, fig. 10, 1843.

’ Giirich, Leitfossilien, Lief. ii, Devon, pp. 156, 157, fig. 42, 1909.
Koch, op. cit., p. 115, pl. iii, figs. 8-10; pl. iv.
Koch, op. cit., p. 32, pl. iii, figs. 1-6.

5 Woodward, GEOL. MAG., Dec. II, Vol. IX, p. 157, Pl. IV; Fig. 1, 1882.

7 Clarke, Foss. Dev. Parana, 1913, pp. 97-101.

8 Tchichatcheff, Asie Mineure, pt. iv, Paléont., 1866, p. 2, pl. i, fig. 8 (figure
not published).

2
4
5

318 Dr. F. Rk. Cowper Reed—The genus Homalonotus.

HT. acanthurus, Clarke,’ and H. parana, Clarke,’ also from the Lower
Devonian. The characteristic feature of these forms, of which only
the pygidium and some doubtful fragments of the thorax are known,
is that the pleure project over the margin of the pygidium as short.
broad lappets in direct continuation and not as separate spines as in
Crypheus. Thischaracter is, however, so unlike that of other groups
of Homalonotus that the reference of these species to this genus seems
extremely doubtful. No figure of the species H. longicaudatus was
given in the original work referred to, but Clarke? figures a specimen
from the Bosphorus under this name. :

Dovustrrut Mrempers or HoOMALONOTUS.

Of species doubtfully referred to the genus Homalonotus we may
mention HH. ? punctillosus, Tornquist,* from the Lepteena Limestone
of Sweden, which has been recorded from the Keisley Limestone ® in
England. This trilobite, by the course of the facial sutures, seems
undoubtedly to belong to another genus.

There is also one described and figured by McCoy from the Kildare
Limestone, Ireland, as H. ophiocephalus,® which seems to be a hypostome
of some other genus, but I have only seen the figured example, and
it is somewhat poor and problematical.

The species Asaphus brevicaudatus (Desl.)," which Bigot® has
removed to Corda’s genus Plesiacomia,? may apparently be regarded
as of independent generic rank, judging from the published descrip- -
tions and figures; but I have not been able to examine any
specimens of it.

Postrion anp AFFINITIES OF HOMALONOTUS.

There has been considerable diversity of opinion with regard to the
position of Homadonotus sens. extenso in any general scheme of
classification of the Trilobita. The genus has usually been put in
the family Calymenide, and Pompecki’’ has pointed out its close
connexion with the genus Calymene and their probable common
descent from Hicks’! genus JVeseuretws, and he was so much impressed
with the evidence of their close affinity as to bring together under
one new generic name Synhomalonotus the combined groups of
those species of Calymene which are comprised in the C. Tristan,
C. Arago, and Ptychometopus Series. But he recognized the existence

! Clarke, ‘‘ Trilob. Grez de Erere e Maecuru, Brazil’’?: Arch. Mus. Nac. Rio
de Janeiro, vol. ix, p. 10, pl. i, figs. 9, 10, 1890.

Z Clarke, Foss. Dev. Parana, p. 97, pl. iii, figs. 5, 6.

> Clarke, ‘‘ Trilob. Grez de Erere e Maecuru, Brazil, p. 14, pl. i, fig. 8

: Crees Undersokn. Siljans. Trilobitf., t. i, p. 44, figs. 46, 57; t. ii
hase 12

2 Reed, Quart. Journ. Geol. Soc., vol. lii, p. 411, 1896.

® McCoy, Syn. Silur. Foss. Irel., 1846, p. 53, pl. iv, fig. 4.

7 Deslongchamps, Mém. Soc. Linn. Calv., ii, pl. ii, figs. 3, 4, 1825.

° Bigot, Bull. Soc. Géol. France, xvi, p. 433, pl. v, fig. 1c, 1888.

° Corda, Prodrome, 1847, p. 55, pl. iii, fig. 30.

10 Pompecki, Neues Jahrb. f. Miner. Geol., Bd. i, pp. 187-248, 1898.

' Hicks, Quart. Journ. Geol. Soc., vol. xxix, pp. 44, 45, 1873.

Dr. fF. R. Cowper Reed—The genus Homalonotus. 319

of two families, the Calymenide and the Homalonotide, and Giirich !
in 1908 adopted this classification. Swinnerton? in 1915 followed
Giirich, but put the two families in a section Calymmenina of a sub-
order Conocoryphida, which he ascribed to Beecher’s group Opistho-
parva because of their supposed derivation from the Olenide.

The family Calymenide (in its wide sense, including Homadonotus)
was put by Beecher in 1900 and by Raymond in 1913 in the group
Proparia on account of the course of the facial sutures. But Giirich
(op. cit.), finding a difficulty in placing it in either of these groups,
instituted a new group, which he called Gonatoparia, for those genera
in which the facial sutures cut the genal angles, and he placed the
Calymenide and Homalonotide in it. Koch, however, had seen that
some of the Devonian species had the point of section in front of the
genal angles, and it is-not improbable that some of those from the
urés de May possessed the same character. If, therefore, we are of
opinion that Beecher’s scheme and principles of classification of
the Trilobita are natural and generally applicable, it seems as if
Homalonotus should be associated with the Proparta rather than
with the Opisthoparia. The idea of the derivation of Homalonotus
from the Olenide, and therefore of its place in the Opisthoparia,
has arisen from its supposed relation to Hicks’ unfortunate genus
Neseuretus, which Pompecki referred to the Olenide, having failed
to see that it was of a composite character. So much confusion and
misunderstanding appears to have arisen about the genus Weseuretus
that a few remarks upon it may here be made. The type-specimens
(all of which are poor) are mostly in the Sedgwick Museum and have
been studied by myself. The first-described species, WV. ramseyensts,
Hicks,? is apparently identical with Calymene Tristani, Brongn.,
which was chosen by Pompecki as the type of his genus Synhomalo-
notus. The second described species, JV. guadratus, Hicks,* is an
indisputable Homalonotus belonging to Salter’s group Brongniartia.
The third species, WV. recurvatus,® is probably referable to Calymene
and seems to resemble H. Hebert:, Barrois,® from the Grés armoricain.
The fourth species, WV. ? elongatus, Hicks,’ may also belong to
Calymene, but the type is in a poor state of preservation, so that
the characters are difficult to distinguish. It is now ascertained
that the beds from which these specimens came are of Arenig and
not Tremadoc age. From the above remarks it appears that
Neseuretus must be regarded as a composite and heterogeneous
assemblage of species and it has no right to be retained as a separate
generic designation.

Apart from all other distinctions the fundamental difference
between Homalonotus and Calymene seems to be that in the former

? Giirich, Leitfossilien, Lief. i, Camb. Silur., 1908, p. 70.

2 Swinnerton, GEOL. MAG., Dec. VI, Vol. II, pp. 494, 540-3, 1915.

° Hicks, op. cit., p. 44, pl. iii, figs. 7-10, 16-22.

* Ibid., p. 45, pl. iii, figs. 11-13, 23-6.

> Tbid., p. 45, pl. iii, figs. 5, 6.

° Barrois, Bull. Soc. Géol. France, ser. 111, vol. xiv, p. 802, pl. xxxvi, fig. 14,
1886.

* Hicks, op. cit., p. 45, pl. iii, figs. 1-3.

320 Dr. F. R. Cowper Reed—The genus Homalonotus.

the facial sutures unite in front on the upper surface of the head-
shield, although frequently very close to the margin, whereas in
Calymene they cut the anterior edge of the head-shield at some
distance apart and are connected together on the lower surface.
In Homalonotus, therefore, the median portion of the front margin
of the head-shield is formed by the epistome, sometimes expanded
and recurved so as to form a broad pre-sutural prora, whereas in
Calymene the same part of the head-shield is composed of the pre-
glabellar post-sutural area, and the epistome is wholly confined to
the lower surface of the head-shield, not appearing at all on the
upper surface. The obsolescence, more or less complete, of the
elabellar lobes and the frequent loss of trilobation in the thorax and
pygidium of Homalonotus are secondary characters of degeneracy,
and can hardly be regarded of primary morphological importance
in comparing the two genera. he correspondence in the number
of segments in the thorax should not have too much stress laid upon
it, for in the fairly homogeneous genus of Jl/enus, which shows
modifications in many respects parallel to Homalonotus, the number
of segments varies from eight to ten.

The earlier species of Homalonotus, such as those from the Grés de
May, show a remarkable resemblance in the characters of the
pygidium to Calymene, and in some species (e.g. H. biserratus) even
the bifurcation of the tips of the pleure near the margin is indicated.
We must, however, remember that even in these early representa-
tives of Homalonotus all the special characters of the head-shield and
elabella are fully developed. The more distinct trilobation of the
body and pygidium is an additional feature in these Grés de May
species, and they undoubtedly come nearest to Cane

It is worthy of remark that the genus Calymene itself did not tend
to differentiate into subgenera, us general character remaining
extraordinarily constant during its whole stratigraphical range,
whereas Homalonotus is not nearly so homogeneous an assemblage
of species, considerable variation having taken place along more or
less distinct lines of development.

We may note a somewhat remarkable parallelism in the generic
life-history of Homalonotus sens. ext. and Asaphus sens. ext., though
in the latter case the development took place more rapidly and
simultaneously, being practically within the confines of the
Ordovician, but in more or less distinct biogeographical areas.
A rounded semicircular or transverse head-shield goes with a
rounded semicircular or transverse pygidium with an entire margin.
A pointed and elongated head-shield accompanies a pointed and
elongated pygidium, and the number of segments in the latter
similarly i increases. A somewhat parallel case exists in the genera
Phacops and Dalmanites.

In Asaphus we may also remark that the facial sutures, which, as
in Homalonotus,. unite on the upper surface, may form a regular
curve or mect in a pointed arch or ogive; they may also lie close to
the margin or well inside it, or may even cut the front edge and be
connected below it. But there is no pair of epistomal sutures
in Asaphus, and the facial sutures cut the hind margin of the

Dr. F. R. Cowper Reed—The genus Homalonotus. 321

head-shield well within the genal angles; so that there can be no
question of direct genetic affinities, but only of homcomorphic
development.

CLASSIFICATION.

The species of Homalonotus may be grouped together into several
sections or subgenera on the strength of the character and course of
the facial sutures, the development of the epistome and doublure,
the degree of trilobation of the thorax, and the shape, trilobation,
and segmentation of the pygidium. ‘These characters are variously
combined, but on the whole two large divisions may be recognized
so far as pygidial characters alone are concerned, one of which is
marked by rounded and the other by pointed pygidia. In the
earliest members of ‘the genus the pygidia are short, rounded, and
composed of few segments, and the trilobation is well marked; in
some of the Devonian species the rounded form again prevails, but
there is a larger number of segments, and the trilobation is more or
less lost. In the Silurian and most of the Devonian species the
pointed elongated pygidium, composed of many segments, with or
without distinct trilobation, is found conspicuously developed.

Many of the groups or sections have already received names from
various authors, but some of these groups are not homogeneous and
require subdivision, as the foregoing remarks have indicated.
Whether these groups are of subgeneric or only lesser rank may be
a matter of opinion; but in the following list the groups appear to
possess combinations of characters of morphological importance, and
it will be observed that the groups also have a stratigraphical relation
or limitation, and therefore suggest phylogenetic significance. We
may therefore maintain that they are not artificial assemblages of
species, but correspond to certain natural divisions of the genus.
In some cases it is unfortunate that the species are only imperfectly
known, or that specific names have been attached to mere fragments
of individuals, or that disconnected portions of doubtful association
have been brought together under the same specific designation.
But these are minor defects which are unavoidable, and subsequent
work may remedy them.

Subgenera.

1. Hohomalonotus, nom. prop. (= Brongniartia (pars), Salter, non
Leach, nee Eaton).

Head-shield transverse, rounded, more or less semicircular. Facial
sutures uniting close to anterior margin or on margin in regular
wide curve, and posteriorly cutting lateral margins slightly in front
of genal angles. Pre-glabellar area wide; pre-sutural band very
narrow or wanting. ‘Thorax with well-marked trilobation; axis
not wider than pleural portions. Pygidium short, broad, expanded,
composed of few segments (six to eight); axis distinct; pleurx
continued to edge or nearly to it; doublure vertical or steeply inclined
at sides, simple, of nearly uniform width all round or narrowing
slightly posteriorly.

DECADE VI.—VOL. V.—NO. VII. 21

322 Dr. F. R. Cowper Reed—The genus Homalonotus

TypeE.—Homalonotus Brongniarti (Desl.).
RANGE.—Lower Ordovician.
DISTRIBUTION.—N. France, Cornwall, Shropshire, Bohemia ?

EXAMPLES.
HA. Deslongchampsi, de Trom. H. Barroisi, de Trom.
HT. Bonissentt, Mor. HI. biserratus, sp. nov.
H. serratus, de Trom. A. quadratus (Hicks).
HA. Vicaryi, Salt. ? H. bohemicus, Barr.
HI. besnevillensis, Bigot. ? H. draboviensis, Novak.
H. wncertus, Bigot. ? H. medius, Barr.
H, Morierei, Bigot.

Remarks.—This section comprises the earliest representatives of
the genus Homalonotus. There is a close connexion between it and
Pompecki’s Synhomalonotus, through which the genus is related to
Calymene.

2. Calymenella, Bergeron.

Head-shield triangular, produced in front into a rostrum. Facial
sutures uniting in front in regular continuous curve at base of
rostrum and inside margin. Pygidium semicircular, transverse,
composed of few segments, distinctly trilobed; axis and pleure well
marked.

TypE.—H. (Calymenella) Boisseli (Bergeron).

RANGE.— Ordovician.

DISTRIBUTION.—France.

EXAMPLE.—H. (C.) Bayani (De Trom. & Lebesc.).

Remarxs.—The peculhar distinguishing feature of this subgenus
is the possession of the rostrum, the precise nature of which has not .
been thoroughly investigated; but it seems to be merely a much
elongated narrow prora, as in Dipleura, and to be wholly pre-sutural
in origin and perhaps epistomal in nature. ‘The head-shield and
glabella in other respects seem to resemble Hohomalonotus, and the
pygidium is unmistakably of the same type. Bergeron regarded the
two species mentioned above as constituting a distinct genus, but
Pompecki considered that it was only a subgenus of Homalonotus.

3. Brongniartella, nom. prop. (= Brongniartia (pars), Salter,
section 1, xon Leach, nec Eaton).

Head-shield rounded, semi-elliptical or semicircular, wider than
long. Facial sutures uniting close to anterior margin or on margin
in regular wide curve, and posteriorly cutting lateral margins nearly
at genal angles. Glabella urceolate, rhomboidal, or subconical,
generally lobeless. Pre-glabellar area of moderate width; pre-
sutural band very narrow or wanting. Thorax with trilobation more
or less indistinct; axis wider than pleural portions. Pygidium
rounded, semi-oval or parabolic, composed of nine to twelve segments ;
axis distinct; pleure continued nearly to margin; border usually
developed but not defined; doublure flat, horizontal, closely in-
folded, of nearly uniform width.

Typr.—H. biswleatus, Salter.

RANGE.—Middle and Upper Ordovician.

DISTRIBUTION.—England.

1 Novak, ‘‘ Zur Kennt. bohm. Trilob.’’?: Beitr. Paleeont. (ist. Ungarns,
p. 27, pl. viii, figs. 9a—-c, 1884. :

Dr. F. R. Cowper Reed—The genus Homalonotus. 323

EXAMPLES.
H. Sedgwicki, Salter. HI. ascriptus, Reed.
H. Edgelli, Salter. - ? A. rudis, Salter.
H. Tawney, sp. nov.

Rramarks.—It was to this group that Salter first applied the name
Brongniartia, choosing H. bisulceatus as the type-species. The
differentiation in structural characters from Synhomalonotus is much
more marked than in Hohomalonotus, particularly in the pygidium,
and all the members of this third subgenus occur on higher horizons
than those of the first subgenus, to which it is, however, closely
related.

4. Trimerus, Green.

Head-shield more or less triangular and elongated. Facial sutures
uniting anteriorly close to but inside margin in a more or less
pointed arch, not forming a continuous regular curve, and posteriorly
cutting genal angles. Pre-glabellar area well developed. Glabella
subconical, occasionally lobed. Thorax with very broad axis and
indistinct trilobation. Pygidium composed of many segments,
triangular, elongated, subcylindrical, ending in a produced acumina-
tion; trilobation faint; doublure very narrow at sides, widening
at tip.

Typr.—H. delphinocephalus (Green).

RANGE.—Silurian (Wenlock).

DISTRIBUTION. —Northern Europe, North America, Australia.

EXAMPLES.
HA. cylindricus, Salt. H. vomer, Chapman.!
H. Harrisoni, McCoy.

Remarks.—VThough in point of stratigraphical succession this sub-
genus follows immediately on that of the H. bisulcatus type, yet the
pygidium represents an almost entirely new and independent form,
and the facial sutures show by their angular junction in front the
nature and origin of the continuous curved commissure in the earlier
sections. There is no direct derivation from the Ordovician forms,
but perhaps links, though at present undiscovered, existed in
Llandovery times.

5. Kenigia, Salter.

Head-shield transverse, broad, short. Epistome projecting in
front as median process; anterior lateral angles of head-shield
angulated forwards, the three together making the margin tricuspid.
Facial sutures bending suddenly inwards near anterior margin and
uniting in a straight or concave transverse commissure with small
median point; posterior branches of facial sutures bent back suddenly
to cut lateral margins nearly at genal angles. Paraglabellar areas
distinctly marked. Pre-glabellar area very narrow. Thorax with
trilobation almost obsolete; axis very broad, scarcely defined.
Pygidium composed of many segments, elongated, acuminate,
triangular, with smooth pointed posterior process; axis nearly

1 Chapman, Proc. Roy. Soc. Victoria, vol. xxiv, N.S., pt. ii, p. 298, pl. lxii,
s. 2,3; pl. lxiii, figs. 1, 2, 1912; Etheridge & Mitchell, Proc. Linn. Soc.

fig
N.S.W., vol. xlii, pt. iii, p. 506, 1917.

324 Dr. F. R. Cowper Reed—The genus Homalonotus.

obsolete, but segmentation of axis and pleure distinct. Doublure
widening posteriorly.

Typr.—H. Knightt, Konig.

RANGE.—Silurian (Ludlow).

DISTRIBUTION.—Northern Hurope.

EXAMPLE.—? H. Johannis, Salt.

Remarks.—This is undoubtedly a highly specialized group in the
genus. A similar sudden bend in the anterior course of the facial
sutures is found in Digonus (q.v.), and the tendency to a projection of
the epistome is seen less developed in Burmeisteria (q.v.). The whole
head-shield of the type-species is, however, marked by very unusual
modifications. It is doubtful if H. Johannis can be closely associated
with it, in spite of its tricuspid front, as the pre-glabellar portion is
different; but the pygidia of the two species are very similar. As
regards the thoracic and pygidial characters of Kenigia it is easy to
see their general resemblance to Zrimerus. The specimens of the
type-species in the Ludlow Museum which I have been privileged to
examine by the kindness of the Curator exhibit the characteristic
features with great clearness, being unusually well preserved.

6. Burmetsteria, Salter (sens. restr.).

Head-shield more or less triangular. Facial sutures convergent
anteriorly and uniting by a double sigmoidal commissure close to
front margin, and posteriorly cutting lateral margins in front of
genal angles. -Pre-glabellar area well developed. Paraglatellar
areas distinct. Glabella occasionally lobed. Epistome projecting
in front of anterior margin of head-shield as median pointed process.
Pre-sutural area very narrow. Thorax with wide, ill-defined axis;
trilobation indistinct. Pygidium triangular, acuminate, strongly
convex from side to side, composed of many segments; axis and
pleurse more or less distinct. Surface of head-shield, thorax, and
pygidium frequently ornamented with more or less regularly disposed
large tubercles or spines.

TypE.—H. Herscheli (Murchison).

RANGE.—Lower Devonian.

DISTRIBUTION.—South Africa, South America (including Falkland Islands).

EXAMPLES.
A. quernus, Lake. H. agrestis, Schwarz.
HZ. colossus, Lake. HI. horridus, Schwarz.
H. perarmatus, Frech. A. lex, Schwarz.
H. hippocampus, Schwarz. H, noticus, Clarke.

Remarxs.—This subgenus appears to be limited to the Southern
Hemisphere. As far as the thorax and pygidium are concerned, its
relations are with Zrimerus, but the anterior course of the facial
sutures seems intermediate between Zrimerus and Kenigia. The
spinosity, which is very irregularly developed in the species, cannot
have as much importance attached to it as some authors have
maintained.

7. Digonus, Giirich.

Head-shield transverse or subtriangular. Middle-shield with
anterior lateral angles rectangular, obtuse, or projecting, and with
anterior margin truncate, straight, or slightly concave. Facial sutures

Dr. F. R. Cowper Reed—The genus Homalonotus. 325

bent in suddenly near front margin and uniting in continuous transverse
commissure. Pre-glabellar area well developed. Glabella short,
subquadrate, or oblong. Thorax with trilobation usually distinct
and well marked. Pygidium triangular, elongated, acuminate, more
or less pointed behind, composed of many segments; trilobation
generally well marked. Surface of thorax and pygidium occasionally
scabrous or tuberculated, but not spinose.
TyprE.—H. gigas, Roemer.

RANGE.—Lower Devonian.
DISTRIBUTION.—Rhenish area, France, ? England, ? Argentina.

! EXAMPLES.
HT. rhenanus, Koch. H. Le Hiri, Barrois.1
HZ, scabrosus, Koch. 2? H. goniopygeus, Woodw.
H. ornatus, Koch. ? H. Kayseri, Thomas.”

Remarxs.—The strange course of the facial sutures in their
transverse union is somewhat like that of Kenzgia and Dipleura, but
the pygidium is closely similar to that of Burmeisteria. The triloba-
tion of the thorax is, however, more distinct than in the latter.
The shape of the glabella is unusual. We are not acquainted with
the true anterior margin of the head-shield, and know nothing about
the epistome. It is very uncertain if the common but imperfectly
known species 7. armatus, Burm., belongs to this subgenus (see below).

8. Burmeisterella, nom. prop.

Head-shield subtriangular, produced anteriorly into upturned
prora formed by epistome and bounded by epistomal sutures. Pre-
sutural area large. Facial sutures bend in suddenly in front and
unite by transverse commissure close to anterior end of glabella.
Pre-glabellar area narrow. Thorax with well-defined cylindrical
axis, of less width than pleural portions; trilobation distinct.
Pygidium semi-oval, rounded, with regular entire margin (in one
species provided with pair of short terminal spines); axis narrow,
elongated, distinct ; composed of many segments; pleure distinct.
Surface of glabella and of thoracic and pygidial axes ornamented
with regularly disposed pairs of large tubercles or spines.

Typr.—H. elongatus, Salt.

RANGE.—Lower Devonian.

DISTRIBUTION.— Devonshire, ? Rhenish area.

EXAMPLES.
H. Champernownei, Woodw. ? H. aculeatus, Koch.?
HY, bifurcatus, sp. nov. ? H. armatus, Burm. (head only).

REMARKS.—Of the type-species we only know the pygidium, but
the very closely allied species H. Champernownei and H. bifurcatus
from the same locality and horizon help us to complete the above
definition. The regular rounded contour, semi-oval shape, well-
defined narrow axis, and regularly paired tubercles of the pygidium

1 Barrois, Bull. Soc. Géol. France, ser. III, vol. xiv, p. 687, pl. xxxiii, fig. 5,
1886.

* Thomas, Zeitschr, deut. geol. Gesell., Bd. lvii, p. 145, pl. ix, figs. 5, 6,
1905.

2 Kochi op. cit.) ps 2ly plea, fie. t

326 Dr. F. R. Cowper Reed—The genus Homatonotus.

sufficiently distinguish this subgenus from the typical H. Herschelv
group. The large pre-sutural area and upturned prora, only known
from the specimen of H. bifurcatus, sp. nov., in the Sedgwick Museum,
are likewise peculiar. But they recall the structure of the head-
shield of Dipleura Dekayt. With regard to the shape and characters
of the pygidium and general well-marked trilobation, we see affinities
with the Ordovician Brongniartella. The paired tubercles on the
glabella and other features of the head-shield of H. armatus suggest
that this species when completely known may have to be placed in
this section. The Rhenish HW. aculeatus has a pygidium apparently
much like that of the new British species H. bzfurcatus. The only
well-known forms are from Devonshire.

9. Parahomalonotus, nom. prop.

Head-shield semicircular, transverse; facial sutures uniting in
regular wide-arched commissure close to anterior margin. Thorax
with axis obsolete and trilobation quite lost. Pygidium rounded,
semicircular, or semi-oval, with entire margin; trilobation more or
less indistinct, but segmentation well marked; border not crossed by
pleure. Surface ornamented with coarse tubercles and granules (or
smooth).

Typr.—H. Gervillei, De Verneuil.!

RANGE.—Lower Devonian.

DISTRIBUTION.—-Europe.

EXAMPLES.
H. pradoanus, De Vern. 2? H. levicauda, Quenst.
H. Barratti, Woodw. ? H. obtusus, Sandb.?
H. Hausmanni, Rouault. ? H. multicostatus, Koch.*

? H. planus, Sandb.

Remarxs.—This subgenus is characterized by the regular curved
union of the facial sutures close to the anterior margin (reminding
us of the conditions in Hohomalonotus and Brongniartella), by the
disappearance of the trilobation in the thorax (as in the Bumastus
group of Jilenus), and by the regular rounded outline, obsolescent
trilobation but distinct segmentation of the pygidium. It looks as if
these characters must be due to reversion, as no Silurian forms are
known to connect the Ordovician species with this Devonian group.
The four last-mentioned examples in the above list differ from the
typical members of this subgenus in several mninor respects, especially
in being smooth, but for the present may be best referred to this
subgenus.

10. Dipleura, Green.

Head-shield subtriangular, with large pre-sutural prora. Facial
sutures uniting in front of glabellaby straight transverse commissure,
but continued directly forwards without deviation into the epistomal
sutures bounding the prora. ‘Thorax with faint trilobation.

1 Tchichatcheff, Asie Mineure, Paléont., p. 448, pl. xx, fig. 1, 1866; Bayle,
Explic. Carte Géol. France, iv, atlas, pl. ii, figs. 1, 8, 6, 1878.

2 Sandberger, Verstein. rhein. Schicht. Nassau, t. ii, p. 26, figs. 6-6d, 1856
Koch, op. cit., p. 49, pl. vi, figs. 1-4.

> Koch, op. cit., p. 52, pl. vi, figs. 5-9.

Dr. F. R. Cowper Reed—The genus Homalonotus. 327
Pygidium triangular, subconical, obtusely pointed behind, with
trilobation obsolete or obsolescent and segmentation very faintly
marked.

Typr.—H. Dekayi, Green.

RANGE.—Middle Devonian (Hamilton Formation).

DISTRIBUTION.—North America.

Remarxks.—This subgenus seems confined to North America and
to be the latest representative of the genus Homalonotus. It is
extremely doubtful if the Harz species H. Schusteri, Roem.,! is
rightly referred to Dipleura by Kayser.? The characteristic features
of Dipleura are the large pre-sutural prora (recalling that of
Burmeisterella), the straight transverse commissure of the facial
sutures (somewhat as in Digonus), the direct continuation of the
facial into the epistomal sutures, and the obsolete trilobation and
nearly obsolete segmentation of the pygidium. The last-mentioned
character is, however, also found in H. levicauda, Quenst., attributed
provisionally to the preceding subgenus, Parahomalonotus.

ConcLusion.

With regard to the stratigraphical distribution of the above-
described ten subgenera of the genus Homalonotus, we note that the
first three, Hohomalonotus, Calymenella, and Brongniartella, are
restricted to the Ordovician, the first one being the earliest; Zrimerus
and Aenigia occur only in the Silurian, and all the rest, Burmetsteria,
Digonus, Burmeisterella, Parahomalonotus, and Dipleura, are found in
the Devonian. It is clear, therefore, that the climax of development
was reached in the Devonian, and it is remarkable that the genus did
not survive this period.

The phylogeny of the genus is imperfectly known. We have seen
that it may be linked with Calymene by means of Synhomalonotus,
though it must have diverged at an early period, or more probably
have originated from a common stock. Within the limits of the
genus the relationships of the different subgenera are difficult to
trace. There is a considerable morphological gap between the
Ordovician and Silurian groups, and transitional forms are at present
unknown. The Devonian subgenera fall into two main groups, one
of which, comprising Burmeisteria and Digonus, suggests a connexion
with the Silurian subgenera, but on the other hand Parahomalonotus
suggests reversion to the earlier types. Burmetsterella in some
respects also points back to Ordovician forms, but it is undoubtedly
highly specialized. Diplewra may be a modification of the Digonus
type, and is the latest representative of the genus in any part of
the world.

I am much indebted to the authorities of the Sedgwick Museum,
Cambridge, the British Museum, the Jermyn Street Museum, the
Shrewsbury Museum, and the Ludlow Museum for the opportunities
afforded me of examining specimens in their collections.

* Roemer, Beitr. z. geol. Kennt. nordw. Harzgeb., iii, t. iii, fig. 20, 1855.
? Kayser in appendix to Koch, op. cit., p. 76.

328 : Notices of Memovrs—Dr. H. _ J. Johnston-Lavis—

NOTICES OF MEMOIRS.

——._—_

_ Brsrioc¢kRaPHy oF THE GroLtocy anv Hruptive PHENOMENA OF THE
MOBE IMPORTANT VOLCANOES OF SouTHEEN Iraty. Compiled by
Henry James Jonnston-Lavis, M.D., D.Ch., M.R.C.S8., F.G.S.,
etc., late Professor of Vulcanology in the Royal University of
Naples, assisted by Madame Awnronza Jonnsron-Lavis. 2nd
edition, completed, after the author’s death, by Miss M. B.
Sranron, and edited, with a preface and a short life of the author,
by B. B. Woopwarp, F.L.S., F.G.S., of the British Museum
(Nat. Hist.). 4to; pp. xxiv + 374, with a frontispiece and a
photograph of the author in 1905. London: The University of
London Press, Ltd., St. Paul’s House, Warwick Square, EC. 4.
1918.

(W\HE history and razson a’étre of this important work are set forth
by the editor, Mr. B. B. Woodward, in his preface, and thence
we extract the following salient facts : —

The ‘‘ Congrés Géologique International”’ having arranged to hold
its second session at Bologna in 1881, the ‘‘Comité d’Organisation”’
in that town decided, in their Séance of March 17th, 1879, to
undertake the compilation of a ‘‘Bibliographie géologique et
paléontologique de l’Italie”’ as a contribution towards the success of
the meeting. For many unavoidable reasons that list was an
imperfect one. Still, a very considerable number of works and
papers were recorded, the total number of entries amounting to
6,566.

Dr. Johnston-Lavis naturally availed himself of those sections
that concerned his special pursuits and set to work to supply
deficiencies and to add the titles of further publications as issued.
In this he was cordially aided by Mme. Lavis, who, working under
her husband’s directions, industriously transcribed the fresh titles
and incorporated them with the entries from the older bibliography.

By the time that the Geologists’ Association paid its visit to
Southern Italy in the months of September and October, 1889, the
bibliography had grown to almost twice the size, and Lavis happily
seized upon the occasion to publish it in 1891 as an appendix to the
account of the excursion, which was reprinted from the Proceedings
of the Association, the whole thus forming a valuable manual of
information on the volcanoes of Southern Italy.

From that time onwards no opportunity was lost for working at
this bibliography and endeavouring to render it as complete as such
a work can ever be.

When the War broke out, depriving him at once of his practice, he
had determined to employ his enforced leisure from professional
duties till happier times should return in systematically revising and
augmenting the whole bibliography and in ransacking every available
source with this object in view.

His tragic death’ cut this project short, and all the loving labour

1 GEOL. MaG., 1914, p. 480.

Bibliography of Volcanoes of Southern Italy. 329

of years of patient research seemed likely to be thrown away had
not his family most felicitously conceived the idea of completing the
work so far as might be possible and publishing it as a worthy
offering to his memory.

Fortunately, this has been rendered practicable through the cordial
co-operation of his secretary, who, during recent years, had been
closely associated with Dr. Johnston-Lavis in the work and was
thoroughly acquainted with his scheme and method. Miss Stanton
accordingly continued the researches that had been begun in the
Library of the Geological Society of London, where the index
catalogue prepared by Mr. C. Davies Sherborn proved invaluable,
the Reading Room of the British Museum, and the Libraries in the
Natural History Museum, extending them to the Library of the
Société Géologique de France, where she met with cordial assistance,
especially from the President, M. Maurice Cossmann, and the former
President, M. Emmanuel de Margerie, and the Bibliothéque
Nationale de France, where, as unhappily customary in that
establishment, all spirit of practical help was conspicuous by its
absence.

In this way the present bibliography was completed, so far as at
present practicable, as regards all the more important volcanoes. ‘To
have extended its scope and to have embraced all volcanic records |
for the region would have entailed many more years of labour, whilst
the value of the bibliography would not have been materially
increased thereby. Nor has it been possible in all cases to incorporate
in their entirety the individual contents of previous bibliographies in
the body of the present one. The existence of such sources of
reference is, however, duly recorded, and the inquirer will, therefore,
be furnished with the necessary clue towards the object of his
research.

On account of the War, all access to Dr. Johnston-Lavis’ own
library was cut off, and hence many entries that might have been
completed have perforce had to be included in a less perfect state
than could have been wished. ‘The whole bibliography must, there-
fore, under the circumstances of its production, be leniently judged
and regarded as a stage only towards that ideal work one would like
to see.

The Editor has to acknowledge much kindly assistance and advice
given during the progress of the work by Sir Lazarus Fletcher,
LEDs ERS:

The subject-matter has been subdivided, as in the previous
edition, according to the different volcanic groups, but some
modifications in these have been introduced that approximately
follow the author’s known intentions in that respect.

Altogether there are in this present edition some 7,350 entries,
and since these include references to the fauna, flora, and
paleontology of the several districts, in addition to their mineralogy,
petrology, vulcanology, etc., the work is obviously one of general
interest and utility to all workers in natural science, and should
therefore find a place on the shelves of every library of any
importance.

330 Reviews—Ordovician and Silwrian Fossils, Yuwn-nan.

RHEVLEWS.-

-I.—Orpovicran anD Sinurran Fossrrs From Yun-nan. By F. R.
Cowper Reep, M.A., Se.D., F.G.S. Paleontologia Indica, n.s.,
vol. vi, Memoir 8, pp. iv + 69, 8 pls., 1917.

INCE 1913 we have known that Mr. Coggin Brown, during his

exploration of South-western Yun-nan a few years previously, had
collected some Lower Ordovician and Silurian fossils. Dr. Cowper

Reed’s complete description of these is at last published, with

excellent illustrations by Mr. T. A. Brock, and with determinations

of the graptolites by Dr. Gertrude Elles.

The Ordovician fossils are from three localities: Pu-piao, La-méng,
and Shih-tien. It was from Pu-piao that Loczy on the Szechenyi
expedition obtained cystid plates referred by him to Hemicosmites.
The rocks here are mudstones with a calcareous band; all are
probably of Llandeilo age, and the mudstones, at any rate, contain
Didymograptus murchisont and its normal associates. The rock at
La-méng resembles that of the Hwe Mawng Beds in the Northern
Shan States of Burma, and the few poorly preserved fossils are
consistent with that horizon. Five types of rock from Shih-tien
probably represent as many beds. The contained fossils show
general agreement with the fauna of the Sedaw Beds in the
Naungkangyi series of the Northern Shan States, and Dr. Reed
inclines to correlate the beds with Schmidt’s stages B and C
(Orthoceras, Echinosphara, and Chasmops Limestones) of the Baltic
region.

The Silurian beds of Shih-tien consist of two kinds of shale, with
two different assemblages of graptolites of Llandovery age. ‘The
higher horizon belongs to the base of the zone of Monograptus
sedgwicki, and its most abundant fossil is JL. lobiferus. he lower
horizon abounds in Climacograpti, not specifically determinable, with
other specimens suggesting the zone of Orthograptus vesiculosus or
the base of the Monograptus gregarius zone. These two horizons
yield no fossils other than graptolites.

Of the Ordovician fossils the most important are the Cystids, in
respect to number both of specimens and of species and in respect to
novelty, there being described two new genera and ten new species.
The genera are Svnocystis and Cvocystis (n.gg.), Pyrocystis,
Hucystis, Spheronis, Echinosphera, Heliocrinus, Caryocystes,
Echinoencrinus, and Caryoerinus. Crinoids are represented only
by one specimen of the fossil which Dr. Reed calls Camarocrinus
asiaticus. Of Brachiopods there are the genera: Philhedra (1 n.sp.),
Orthis (1 n.sp.), Hemipronites (1 u.var.), Rafinesquina(?), Plectam-
bonites, Streptis, and Porambonites. Lamellibranchs are represented
by undetermined species of Ctenodonta and Conocardium ; and Gastro-
pods by doubtfully determined species of Holopea, Raphistoma,
Bellerophon, Cyrtolitina, and Hyolithes. Cephalopods are numerous,
especially at Shih-tien, and belong to Hndoceras, Orthoceras (1 n.sp.),
Jovellania, Cameroceras(?), Actinoceras, Spyroceras(?), Trocholites
(1 n.sp.), Letuctes, and Tarphyceras(?). The few and often fragmentary
remains of 'rilobites are referred to Harpes, Remopleurides, Asaphus,

Reviews—F. W. Harmer—Glacial Geology. 351

Ogygites (1 n.sp.), Lllenus (6 spp., of which 1 is new), WVileus,
Bathyurus (1 n.sp.), Lichas, Calymene (1 u.sp.), and Pliomera
1 n.sp.).

ie aaa of the faunas from all three localities, apart from
obvious similarity to those of the Shan States, are in Dr. Reed’s
opinion closest with those of North-West Europe. This is perhaps
more noticeable in the cephalopods than in the cystids. The
Echinosphera Limestone of the Baltic Provinces and Scandinavia
certainly has an ‘‘abundance of cystideans”, but the general
composition of its cystid fauna is not much like that of Shih-tien.
On the contrary, connection with North America is closely indicated
by some of the new cystids, possibly by the so-called Camarocrinus,
and certainly by such cephalopods as Actinoceras cf. brgsbyi and the
Jovellania.

The descriptions give sufficient detail, and Dr. Reed seems to have
extracted a good deal of information from material sometimes
unpromising. Dr. Reed’s knowledge of these Ordovician faunas is
undoubtedly ‘‘extensive’’, but he might realize that it is also
“peculiar”, and might sometimes make matters easier for his less
learned colleagues by stricter attention to the technical presentation
of his results. ‘Thus, he gives a full description, with five figures, of
Hemipronites giraldi var. nov. yunnanensis; but he entirely fails to
indicate in what it differs from the original species-form. Similarly,
in addition to the page-and-half description of Ogygites yunnanensis,
n.sp., 1t would have been well to furnish a brief specific diagnosis ;
a few other species of the genus are mentioned, but the differences
are indicated for only two of them. A little more attention to
matters of this kind would be a great help to the weaker brethren,
and would add to the gratitude they feel for these interesting
accessions to our knowledge from the outermost fringes of empire.

IJ.—Tue Gracian Grotoey or Norrork anp Surrorx. By F. W.
Hanmer, F.G.S. pp. 26, with 7 figures and a contoured map.
London: Jarrold & Sons; Dulau & Co., Ltd., 37 Soho Square, W.1.

N this small book, reprinted from the Transactions of the Norfolk
and Norwich Naturalists’ Society, vol. ix, Mr. Harmer gives
a summary, written in a somewhat popular style, of his well-known
work on the glacial deposits of East Anglia, and of the important
conclusions that he has been able to draw as to the sequence of
events in that area during the Pleistocene period. For more than
fifty years Mr. Harmer has devoted most of the leisure of a busy life
to this subject, and his conclusions are naturally deserving of the
most careful consideration.

‘he lower part of the glacial series is classed under the collective
name of the North Sea Drift, including the Cromer Till and Con-
torted Drift of other authors. This contains numerous far-travelled
erratics from Scotland and Scandinavia, of quite unmistakable
types, and the source of this material is not a matter of controversy.
The brickearths of the interior of Norfolk may be taken to represent
the moraine profonde of the North Sea ice-sheet, while the Cromer

332 Reviews—J. F. Kemp—The Outlook for Iron.

ridge isits terminal moraine at some stage of the retreat. But when
we come to consider the higher members of the glacial series the
question is not quite so simple. It is quite clear that in Kast Anglia
there are two boulder-clays, divided by sands and gravels; the most
notable feature of the upper one, which is equivalent to the Chalky
Boulder-clay of the Midlands, is the presence of enormous quantities
of Kimeridgian material, which can only have come from the north-
west, that is in a direction more or less at right angles to the flow of
the North Sea Glacier. Mr. Harmer considers that this ice, his
Great Eastern Glacier, originated in the mountains of the North of
England and flowed down the Vale of York, across Lincolnshire, and
over the Fenland, being reinforced by lateral glaciers descending
from the Pennine valleys and by ice coming up the Humber gap
from the North Sea. Hence it contains a great variety of Jurassic
and Cretaceous erratics, especially Kimeridge Clay, Neocomian sand-
stones, hard Chalk, and characteristic tabular flints from Lincoln-
shire, the latter being very abundant and easy to recognize. This
second glacier ploughed up and incorporated in its own deposits
much of the North Sea Drift, so that the westward extension of the
latter is ill-defined. This hypothesis explains in a satisfactory
manner the abundance of Kimeridgian material in Norfolk and
Suffolk, which is difficult or impossible to account for in any other
way. Granting the fundamental assumption that land ice can move
in any direction for any distance over a more or less flat surface, the
rest is easy. It is also shown by a study of the relation of the drifts
to the valleys of Norfolk that great denudation took place between
the deposition of the two boulder-clays, and this fact is of much
interest in connexion with the question of the occurrence of inter- -
glacial periods, since a long interval of time is indicated, which may
correspond to one of the warm periods of Penck and Briickner. The
origin of the plateau gravels and valley gravels of the area may also
be ascribed to the torrential waters set free during the later stages
of the melting and retreat of the ice.

It will thus be seen that this book contains in a very condensed
form a summary of an enormous amount of work and presents
problems of absorbing interest, which will probably continue to
occupy the attention of geologists for a long time to come.

Jee dals 1a,

IIJ.—Tue Ovrtook ror Iron. By J. F. Kemp. From the Smith-
sonian Report for 1916, pp. 289-809. Washington, 1917.

ie these few pages the author gives a resumé of our present

knowledge of the reserves of iron-ore still available, with special
reference to the United States. The general conclusion is that while
the supplies of high-grade ore are distinctly limited, the reserves
of low-grade ore are practically inexhaustible. The output of ore
from the Lake Superior region, for example, cannot be kept up to the
present production with a minimum of 50 per cent of iron for more
than fifty years, while ona similar basis the Clinton ores of Alabama,
Tennessee, and Georgia can be considered as assured for a little over
100 years. Hence for a successful continuance of iron-smelting in

Reviews—A. P. Coleman—Dry Land in Geology. 3338

the United States one of three things must occur: either a great
improvement in metallurgical processes, rendering the employment
of low-grade ores remunerative, or some change of economic con-
ditions leading to a similar result, or the great development of foreign
sources of supply accompanied by cheap transport. In conclusion,
some attention is paid to the amount of coke likely to be available in
the future for iron-smelting; no apprehension is felt of any failure
in this quarter, since apparently the fuel will last longer than the
iron-ore.

day salnel ie

IV.—Dry Lanp 1n Geotocy. By A. P. Coneman. Smithsonian
Report for 1916, pp. 255-72.

fP\HIS is a reprint from the Bulletin of the Geological Society of

America of the Presidential Address for 1915. It is pointed
out that all the earlier geologists confined their attention almost
exclusively to marine deposits, because these contain abundant
fossils, whereas in terrestrial deposits they are scarce or wanting.
It is only of recent years that the importance of the latter group has
been recognized. ‘The chief types are arid and glacial respectively ;
arid deposits have now been found or imagined in all systems except
the Ordovician and Jurassic, and it is possible that the idea has been
overdone, since it is not proved that all red sandstones were
necessarily formed in deserts. A careful study also shows a remark-
ably close association between arid and glacial deposits; at first sight
this seems improbable, but it is actually occurring in the world
to-day: The primary question of the origin of the land remains
unanswered; we can only suppose it to be due on isostatic principles
to an accidentally uneven distribution of density in the globe, and
unless we are prepared to admit flow of rock-material below the
crust on a gigantic scale it seems to follow that continents and ocean
basins must be on the whole permanent features, and adjustments of
the boundaries of sea and land have been confined to the margins of
continental masses.

Re ES Re

REPORTS AND PROCHEDINGS.

GroLoeicaL Socirty or Lonnpon.

May 1, 1918.—G. W. Lamplugh, F.R.S., President, in the Chair.

Dr. A. Hubert Cox, M.Sc., F.G.S., delivered a lecture on the
Relationship between Geological Structure and Magnetic Dis-
turbance, with especial reference to Leicestershire and the Con-
cealed Coalfield of Nottinghamshire.

Before the lecture, at the request of the President, Dr. A. Strahan,
F.R.S., Director of the Geological Survey, briefly outlined the
circumstances that had led to an investigation into a possible
connexion between geological structure and magnetic disturbances.
The magnetic surveys conducted by Riicker and Thorpe in 1886 and

334 Reports & Proceedings—Geological Society of London.

1891 had proved the existence of certain lines and centres of
disturbance, but those authors observed that ‘‘ the magnetic indica-
tions appear to be quite independent of the disposition of the newer
strata”, and he (the speaker) had not been able to detect any
obvious connexion with the form and structure of the Palsozoic
rocks below. In 1914-15 a new magnetic survey was made by -
Mr. G. W. Walker, who confirmed the existence of certain areas of
disturbance. It was suggested that the effects might be due to
concealed masses of iron-ore, and the matter was referred to the
Conjoint Board of Scientific Societies, who appointed an Iron-Ores
Committee to consider what further steps should be taken. The
Committee recommended that attention should be concentrated on
certain areas of marked magnetic disturbance, and that a more
detailed magnetic survey of these areas, accompanied by a petro-
logical survey and an examination of the magnetic properties of the
rocks of the neighbourhood, should be made. He (the speaker) had
been approached with a view to the petrological work being under-
taken by the Geological Survey, and it had been arranged by the
Board of Education, with the consent of H.M. Treasury, that a
geologist should be temporarily appointed as a member of the staff
for the purposes of the investigation. Dr. Cox had received the
appointment, and the lecture which he was about to deliver would
show that results of great significance had been obtained by him.
The new magnetic observations had been made by Mr. Walker, and
the examination of the specimens collected, in regard to their
magnetic susceptibility, had been conducted by Prof. Ernest Wilson.

Dr. Cox then described the selected areas, which lay on Lias and
Keuper Marl between Melton Mowbray and Nottingham, and in
the neighbourhood of Irthlingborough, where the Northampton
Sands are being worked as iron-ores. The Middle Lias iron-ores,
consisting essentially of limonite, which crop out near Melton
Mowbray, have been proved incapable, by reason of their low
magnetic susceptibility, of causing disturbances of the magnitudes
observed, while the distribution of the disturbances showed no
correspondence with the outcrop of the iron-ores. Nor was any
other formation among the Secondary rocks found capable of exerting
any appreciable influence. It appeared, therefore, that the origin
of the magnetic disturbances must be deep-seated.

Investigation showed that the disturbances were arranged along
the lines of a system of faults ranging in direction from north-west
to nearly west. The faults near Melton Mowbray have not been
proved in the Paleeozoic rocks, and, so far as their effects on the
Secondary rocks are concerned, they would appear to be only minor
dislocations. But farther north, near Nottingham, faults which
take a parallel course, and probably belong to the same system
of faulting as those near Melton Mowbray, are known from evidence
obtained in underground workings to have a much greater throw in
the Coal-measures than in the Permian and Triassic rocks at the
surface. It appears, therefore, that movement took place along the
same lines at more than one period, the earlier and more powerful
movement being of post-Carboniferous but pre-Permian age, the

Reports & Proceedings—Geological Society of London. 335

later movement being post-Triassic. Accordingly, it is probable
that the small dislocations in the Mesozoic rocks indicate the
presence of important faults in the underlying Paleozoic.

The faults can only give rise to magnetic disturbances if they are
associated with rocks of high magnetic susceptibility. It is known
from deep borings that the concealed coalfield of Nottinghamshire
extends into Leicestershire, but how far is not known. Deep
borings have proved that intrusions of dolerite occur in the Coal-
measures at several localities in the south-eastern portion of the
concealed coalfield and always, so far as observed, in the immediate
vicinity of faults. It has been established that dolerites may exert
a considerable magnetic effect; and the susceptibility of those that
occur in the Coal-measures is above the general average. Further,
no other rocks that are known to occur, or are likely to oceur under
the area, have susceptibilities as high as the dolerites found in the
Coal-measures. These facts suggest the possibility of the occurrence
of dolerites intrusive into Coal-measures beneath the Mesozoic rocks
of the Melton Mowbray district.

The distribution of the dolerites actually proved, and of those the
presence of which is suspected by reason of the magnetic dis-
turbances, appears to be controlled by the faulting. Moreover,
whereas the character of the magnetic disturbances is such that it
would not be explained by a sill or laccolite faulted down to the
north, in the manner demanded by the observed throw of the
principal fault, it would be explained by an intrusion that had arisen
along the fault-plane. The faulting itself is connected with a
change of strike in the concealed Coal-measures, and the incoming of
doleritic intrusions in the concealed coalfield, in contrast with their
absence from the exposed coalfield, appears to depend upon the
changed tectonic features. ‘Vhe change of strike is apparent, but to
a less degree, in the Mesozoic rocks which, in the neighbourhood of
Melton Mowbray, have suffered a local twist due to the development
of an east-and-west anticlinal structure.

In view of the evidence that later movements have, in this district,
followed the lines of earlher and more powerful movements, it
appears possible and even probable that this post-Jurassic (probably
post-Cretaceous) anticline is situated along the line of a more pro-
nounced post-Carboniferous but pre-Permian anticline. In this
connexion the isolated position of Charnwood Forest has a consider-
able significance. The Forest is situated on the prolongation of the
east-and-west line of uplift, and just at the point where this uplift
crosses the line of the more powerful north-westerly and south-
easterly (Charnian) uplift. Where the two lines of uplift cross the
elevation attains its maximum, and the oldest rocks appear.

The main line of faulting and of magnetic disturbance is parallel
with and on the northern side of the east-and-west anticline, and
the faulting is of such a nature that it serves to relieve the folding
while accentuating the anticlinal structure. It 1s possible that this
belt of magnetic and geological disturbance marks the southern limit
of the concealed coalfield. The results obtained by joint magnetic
and geological work have thus served to emphasize the real

336 Correspondence—R. Bullen Newton.

importance of a structure which, when judged merely from its effects
on the surface rocks, appears to be of only minor importance.

A further series of observations was carried out on the Jurassic
iron-ores of the Irthlingborough district of Northamptonshire. The
ores occur in the form of a nearly horizontal sheet of weakly
susceptible ferrous carbonate partly oxidized to hydrated oxides.
They give rise to small magnetic disturbances which are quite
capable of detection, and these may be of use in determining the
boundaries of the sheets in areas not affected by larger disturbances
of deep-seated origin.

The results obtained by the joint magnetic and geological work in
the two areas show that this method of investigation may be used to
extend our knowledge of the underground structure. It appears also
that an extension of the method to other parts of the country would
yield information of considerable scientific and economic importance.

Geological maps were exhibited by Dr. A. Hubert Cox, M.Sc.,F.G.S.,
in illustration of his lecture.

CORRESPONDENCE.

RICHARD HALL.

Srr,—Excellent notices have appeared recently in Mature and in
the Gronogicat Magazine calling attention to the important work
accomplished by Mr. Richard Hall, now retired, during his thirty-
eight years of service in the Geological Department of the British
Museum as a ‘‘ preparer of fossils ’’.

Sufficient stress has not been laid on Mr. Hall’s skill in the
development of invertebrate fossils, also in the preparation of
delicate microscopic objects and the cutting and polishing of rock-
surfaces exhibiting organic structures. Special attention might be
called to the large series of sections of Monticuliporoid corals figured
and described by Dr. Foord, Mr. Robert Etheridge, jun., and the late
Professor H. A. Nicholson.

He also made the large sections on glass of the Paleozoic corals
now in the Geological Department, which enable the student to
study with ease the internal characters of the Cyathophylloid and
other groups. Later he prepared microscopic sections of Foraminiferal
rocks which proved of material assistance in researches in the geology
of Africa, Madagascar, New Guinea, Borneo, etc. It is a surprising
fact that an operator who could so successfully disentomb from its
matrix a great reptile like the Pariasaurus should have been equally
proficient in the preparation of delicate sections of microscopic
objects. R. Butren Newron.

MISCHIILUAN HOUVUS.

Luptow Musrum.—We are glad to learn that the Ludlow Natural
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Mrs. Agnes Mary White, daughter of the well-known geologist, the
late Mr. Humphry Salwey, of The Cliff, Ludlow. It is a welcome
contribution to the funds of an important institution which has
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Decade VI.—Vol. V.—No. VIII.

CEOLOGICAL MAGAZINE

OR

Monthly Journal of Geologn.

BEssSCIeh Geni @iii\OG Sse.

EDITED BY

HENRY WOODWARD,

lke Was

FelReSoq PoG@isaSeq aCe

ASSISTED BY
PROFESSOR J. W. GREGORY, D.Sc., F.R.S., F.G.S.
Sir THOMAS H. HOLLAND, K.C.1.H., A.R.C.S., D.Sc., P.R.S., Vicr-Pres. G.S.
Dr. JOHN EDWARD MARR, M.A., Sc.D. (Cams.), F.R.S., F.G.S.
Sir VE MMROM. i. MAI. MAC ScD: (CAnrs.)) DRESS Gest
PROFESSOR W. W. WATTS, Sc.D. (CamsB.), M.Sc., F.R.S., F.G.S.

Dr. ARTHUR SMITH WOODWARD, F.R.S., F.L.S.,

Gre Soc.

AUGUST, 1918,

CONTE

I. ORIGINAL ARYICLES. Page
Eminent Living Geologists: George
W. Lamiplugh, F.R.S., President
Geological Society. (With a

IPoreinmnin, Ie SUL) Pocendcsconanse 337
On a Hypersthene Andesite from
Pitcullo, Fife. By D. BALSILLIE,

IN GooSieenbacend onal ce arch coun ann Geene Hen 346 |

The Zone of Belemnitella mucro-
nata in the Isle of Wight. By
R. M. BRYDONE, F.G.S. (With
a Text-figure.)

Recent Geological History of the
Baltic and Scandinavia. By Sir
HENRY HowortH, K.C.1.E.,
TEI MotSian di aSia/Nan lta Crals\aapoocoean sor B54

The Genesis of Tungsten Ores. By
Ree RASMAT, MOA. SHE Gss:
(Concluded. )

II. REVIEWS.

The Barberton Gold-mining District,
South Africa. By A. L. Hall.. 371

Department of Mines, Canada...... 371

Geology and Ore-deposits of Burma.

By J. Coggin Brown, F.G.S...... 372

Minerals used in Arts and In-
dustries: Corundum. By P. A.

IWHiaOI GIR Mameiseiatcasiice <eoetesnanecn 373
Flint Implements in Suffolk. By
JPMRCTURNG sc sasdhecc se scent 373

LONDON: DULAU &

aSEP 3

AEVIEWS (continued). Page
Geolosyof OpdighameDistrict ... 374
S. W. Whiston: “Phylogeny of

JEU) O) HIKE NSh are N an GeGsuRU Ain aa 374
G. A. Boulenger: Eocene Lizards
ial 1 MeehaKAesenbanetmesbosonon dos wocenees GUD)

Prof. Cl. Gaillard : On Heterosorex 376
Dr. A. Windhausen: Patagonian
Geology 376
Dr. L.L.Fermor: On ‘‘ Hollandite’’ 376
E. Lindeman: Iron-ore in Canada 377
Dr. R. L. Sherlock & B. Smith:
Mineral Resources of Great Britain 377

III. REPORTS AND PROCEEDINGS.
Geological Society of London—

IN Meng alts)5, ISIS ae casos consedsocueadds 377
JAE! OVO eas eRe aE eM Naratin ag: 377
dohaverdlG) Baaaserouwae euen sua moan ace Gene 373
Mineralogical Society.................. 380

IV. CORRESPONDENCE.

eMmOldrenimevcypceeasecc coc oscen cones 380
Crane BvomeWendiecca-cssccc: (se ceeee 381
V. OBITUARY.

William Lower Carter, M.A.,
EVG.S: ((Wath’a Portrait.)| ...... 382

John Watson, M.A., F.G.S......... 383

Professor V. Amalitsky............... 384

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PLATE XII.

Grou. Maa., 1918.

THE

GHOLOGICAL MAGAZINE

NEW SERIES HDECA DIE Nil) i: VOL Mi.

No. VIII.—AUGUST, 1918.

OREG TINA T,)) Aura r Geass)!

1.—Eminent Livine GEoLoeists.

Grorce Witiiam Lamptuen, F.R.S., President Geol. Soc., Assistant
Director of the Geological Survey of England and Wales.

(WITH A PORTRAIT, PLATE XII.)

T has frequently been asserted that the “born geologist’’—as
distinguished from the geologist made by education and training
—owes his conception chiefly to the formation on which he happens
to be born. Nor is it the beauty of the scenery and the attractive-
ness of firth and fell, mountain and glen, that usually give the
impulse in the making of the geologist. It comes in most cases from
the fossils he sees strewn around him in quarry or hillside—things
that can be collected and fascinate the youthful mind even more
than the rocks themselves. But whether the strata or the fossils are
the stimulus required, it is beyond dispute that Yorkshire—in which
both are .conspicuous — takes a leading place in England as the
birthplace of so many eminent geologists in the past century, and
amongst them the subject of our present sketch worthily deserves to
find a place.

George William Lamplugh was born at Driffield, Kast Yorkshire,
on April 8, 1859, and here he spent his early years until he removed
with his widowed mother to the coast at Bridlington when he was at
the impressionable age of 13. It is scarcely possible that anyone
haying any sympathy with Nature should spend his youthful days
upon the Yorkshire coast without becoming more or less of
a geologist. Young Lamplugh soon began to collect the fossils from
the Chalk and Drift, the latter deposit being a veritable open-air
museum from the variety of its transported rocks and fossils. From
the desire to know more about his collections he was led to the
serious study of geology and to seek association with Yorkshire
geologists, always a numerous and kindly folk. Amongst these he
met with members of the Geological Survey working at the time
in the district. Thus began a lasting friendship with the late
J. R. Dakyns, with whom he spent some holidays in the field in
various parts of the country. Circumstances compelled Lamplugh to
enter early into business, but he resolutely determined to make
science the serious object of his life, even if it did not procure for
him the necessary means of livelihood.

Among the geological deposits on the Yorkshire coast that soon
attracted Lamplugh’s attention was the Boulder-clay series, to the

DECADE VI.—VOL. V.—NO. VIII. 22

338 Eminent Living Geologists—G. W. Lamplugh.

divisions of which, and in particular that known as the Bridlington
_ Crag,! he devoted very careful work, and published the results in
a series of papers, commencing in the Grotoercan Magazine for
November, 1878 (pp. 509-17), in which the position of the shell-
bearing beds in relation to the Boulder-clay, sands, and gravels is
shown.

Besides the additions to the marine fauna made by Mr. Lamplugh
(and identified by Dr. H. Woodward, F.R.S.), he records the
discovery (in 1879, op. cit., p. 393) of a freshwater deposit rich in
shells of Limnea peregra, suggesting envelopment and transportation
by the land-ice of both freshwater and marine deposits with the shells
peculiar to each. He also read a paper in 1879 to the Yorkshire
Geological and Polytechnic Society ‘‘On the Glacial Beds in Filey
Bay” (the first of a series on kindred subjects communicated to this
Society extending over many years).

It happened that the year 1881 was not only famous as the Jubilee
of the British Association for the Advancement of Science, but the
meeting was held in York, the city in which the Association was
founded in 1831. The rally made by geologists, under the presidency
of Professor (afterwards Sir A. C.) Ramsay, was truly remarkable,
and the geologists of Yorkshire, amongst whom was G. W.
Lamplugh (then 22), attended in force and gave it their whole-
hearted support. Lamplugh’s contribution to the splendid lst of
papers read in Section C was ‘‘ On the Bridlington and Dimlington
Glacial Shell-beds” (Grot. Mae., 1881, pp. 5385-46), with an
excellent section of the cliff and lists of the Mollusca by Dr. J. Gwyn
Jeffreys, of the Foraminifera by T. Rupert Jones, W. K. Parker, and
Dr. H. C. Sorby. The recurrence of many papers on the Bridlington
shell-beds is not merely due to their great importance, but to the
fact that these beds are only occasionally seen, being almost con-
stantly ‘‘masked” by masses of shingle and sand piled above them
by the wind and tides, and moreover they are being gradually but
permanently lost to sight by the construction of additional sea-walls
to prevent the encroachment of the sea upon the cliffs. But for
Lamplugh’s long resedence on gthe spot, their latest history woubd
probably never have been written.

Lamplugh’s first paper read before the Geological Society of
London, in February, 1884, was on a recent exposure by storms of
the shelly patches in the Boulder-clay at Bridlington in the winter
of 1882-3. The mollusca, examined and determined by Dr. J. Gwyn
Jeffreys, had been increased from 67 to 101, five of the additions
being new to science; the Cirripedia were also determined by
Mr. E. T. Newton and Foraminifera by Dr. Crosskey.

This year marked a determinative step in Lamplugh’s life (he
calls it his ‘‘ wander-year”’), for in it he started on a year’s tour in
North America for the purpose of increasing and enlarging his

1 The history of the Bridlington Crag is given in a paper by the late
Dr. S. P. Woodward in this journal, Vol. I, p. 49, 1864, which records details
of the various early investigators and a list of the shells in this deposit com-
pared with the Coralline Red and Norwich Crag, the Glacial deposits, and
living species.

Eminent Living Geologists—G.W. Lamplugh. 339

geological and general knowledge. The philosopher says ‘‘ know
thyself’’; geologists say ‘‘ know the world”’, and to do this a man
must travel, travel, travel. He must possess also the trained eye
and the retentive memory of the intelligent observer. After some
study of drifts in the Eastern and North Central States, Lamplugh
drifted gradually westward to the Pacific Coast, Vancouver Island,
and Alaska. In winter he journeyed south to the Mexican border
and as far as New Orleans. Afterwards he described a visit to the
Muir Glacier in Vature and some features of glaciation observed in
Vancouver Island in the Proceedings of the Yorkshire Geological and
Polytechnic Society and in the Quarterly Journal for 1886.

On returning home Mr. Lamplugh took up with his accustomed
activity his old geological exploration of the Yorkshire coast,’ and
especially devoted his attention to the subdivisions of the Speeton
Clay. His notes on this formation in the Excursion Guide pre-
pared for the London meeting of the International Geological
Congress in 1888 brought him into personal association with several
distinguished Continental geologists, who visited Speeton under his
guidance, and led him to communicate an important paper on the
subject to the Geological Society in March, 1889. This paper gave
the results of a long series of observations made by him, during
favourable opportunities, at the cliff foot and on the beach at
Speeton from 1880 to 1889. As the result of his exhaustive labours
he was able to show, on stratigraphical and paleontological evidence,
that there is probably at Speeton a continuous series of clays from
the Jurassic to the Upper Cretaceous, and that the deposition of
these beds had gone on contemporaneously with the erosion of the
beds inland.

This exploration of the Speeton Clay attracted the particular
attention of the Russian geologist Professor Dr. Alexis P. Pavlow,
of the University of Moscow. A critical study of the fossils by
Professor Pavlow gave rise to a joint paper on the Speeton Clay
and its Equivalents by A. Pavlow and G. W. Lamplugh.? In
it the authors showed by comparative stratigraphy, and on the
evidence of the Mesozoic Cephalopods from Russia, this, and other
countries, the different ‘‘zones’’? into which the Speeton and
Russian beds have been divided, and the actual sequence from the
Kammeridgian to the Aptian.

In the award to Mr. Lamplugh of the ‘‘ Lyell Geological Fund”
by the Council of the Geological Society in February, 1891, the
President, Sir A. Geikie, referred to his valuable researches among
the Glacial deposits of Yorkshire, and particularly to his “investiga-
tion of the Speeton Clay, as a striking example of the results
obtained by long and patient labours of an observer resident on the
spot with unusual facilities to examine and study the beds.

In 1892 the opportunity so long awaited was afforded Lamplugh
to join the Geological Survey as an Assistant Geologist, and, as

oe

1 He once described himself as
science.

? Published in the Bull. Soc. Imp. Nat. Moscou with 11 plates (Moscow,
1892); see also GEOL. MAG., 1892, pp. 422-6.

a coastguard ’’ in the service of geological

340 Eminent Living Geologists—G. W. Lamplugh.

evidence of the high opinion held by the Director of his qualifica-
tions, he was sent to survey the Isle of Man, a task in which he was
occupied for the greater part of the succeeding five years. The
results of this period are embodied in his papers to the volumes of
the Quarterly Journal and the Survey Memoir on the Isle of Man.

It is not often that one geological surveyor has the pleasure and
satisfaction of seeing his name recorded as having written a memoir
entirely by himself. The late Professor J. W. Judd when on the
Survey many years ago claimed to have completed a whole English
county, that of Rutland, but Mr. Lamplugh surveyed a whole
island; nay, more, for was not Man a kingdom in itself up to 1765,
when the Duke of Athol ceded his rights as Lord of Man to the
Crown; but it still has its own Parliament (the House of Keys).
Three-fourths of its whole area of 227 square miles (145,325 acres)
is probably of Upper Cambrian age, whilst borings through Glacial
drift have revealed a rock-floor of Triassic, Permian, and Lower
Carboniferous strata below sea-level. Besides its valuable mines of
silver-lead ore, its shell-marl and peat deposits have yielded many
remains of the ‘‘ Gigantic Irish Deer”’ (including an entire skeleton
now set up in the Castle Rushen Museum, Isle of Man), which
animal Mr. Lamplugh suggested may have crossed over to Man upon
the ice towards the close of the Glacial period !!

A brief leave of absence having been granted him, early in 1893
Mr. Lamplugh paid a flying visit to Arizona and the Pacific Coast of
America and had a glimpse of the Grand Canon of the Colorado.

Four years later, having been appointed Secretary of Section C
(Geology), he attended the meeting of the British Association held
in Toronto, Canada, and he joined an excursion across the Dominion
to Vancouver Island under the guidance of Dr. G. M. Dawson, F.R.S.,
an account of which he published in Nature for November, 1897.
In 1898 Mr. Lamplugh removed to Tonbridge to take part in the
mapping of the Weald in conjunction with the examination of the
borings and sinkings for coal then in progress in Kent (see memoir
with Dr. Kitchin on Kent Mesozoic Rocks, 1911).

In 1901 the Council of the Geological Society awarded to him
the Bigsby Medal (the ‘‘young man’s medal’’). In handing it to
Mr. Lamplugh the President, Mr. Teall, said: ‘‘The Council feel
that they are placing it in safe hands. You have done much, and
they confidently expect that you will do more’’:—a trust which has
since been honourably fulfilled by the recipient.

Having been appointed ‘‘ District Geologist” in 1901, Mr. Lamplugh
was sent to Dublin in charge of the Irish branch of the Geological
Survey, in which post he remained until the Survey was transferred
to an Irish department and placed under the supervision of
Professor Grenville A. J. Cole, F.R.S., in 1905. During the period
~ of his residence in Dublin Lamplugh superintended and took part in
the mapping of the country around Dublin, Belfast, Cork, and
Limerick, and issued four memoirs dealing with these areas.

' Another skeleton of Cervus megaceros, discovered in the Isle of Man in
1819, was presented to the Edinburgh Museum by the Duke of Athol. Many

other remains of the same deer haye been met with from 1798 onwards (see
Geol. Surv. Mem., 1903,spp. 377-88).

Eminent Living Geologists—G. W. Lamplugh. 341

In 1905 Mr. G. W. Lamplugh was elected a Fellow of the Royal
Society, and in the same year he undertook, under the auspices of
the British Association, the examination of the almost unexplored
gorge of the Zambesi below the Victoria Falls, one of the grandest
features of natural scenery to be met with on the African Continent.
‘“‘Tt is difficult,” says Mr. Lamplugh, ‘‘for anyone standing on the
brink of the chasm, after having seen the placid flow of the Zambesi
above the Falls, to believe that the fissure into which the river is so
suddenly precipitated had been formed gradually by the action of
the river itself, and not by some great convulsion during which the
very crust of the earth was rent. The narrowness of the abyss, the
strange zigzags along which the tumultuous waters rush, after their
first great plunge, the mystery which has long surrounded the
further course of the river after it swings away out of sight among
its forbidding precipices, and the knowledge that the rocks across
which it plunges are of volcanic origin are all factors that have
aided the illusion.” The conclusion arrived at by Mr. Lamplugh
after examining the river carefully was quite in agreement with that
already advanced by Mr. A. J. C. Molyneux that the prevalent idea
of a sudden rent of the earth’s crust was inadequate to explain the
phenomena observed around the Falls, but was compatible with the
view that the river has slowly sunk its channel into the hard rocks
which have barred its passage seawards, while evidence afforded in
other parts of the world sufficiently proves that canyons of even more
impressive dimensions than the Zambesi have been carved out by the
erosive agency of water acting through very long periods of time.!

In the following year Mr. Lamplugh was elected President of the
Geological Section of the British Association in York and delivered
an address on ‘‘ Interglacial Problems”’.

Upon his return from Ireland he took charge of the survey of the
Midland District (Nottinghamshire, etc.), and shared as writer and
editor in the publication of several memoirs (see list). Subsequently
he superintended the field-work in the North Wales district, the
full results of which are not yet published.

In 1910 Mr. Lamplugh attended the meeting of the International
Geological Congress at Stockholm; and previously to the meeting he
joined with other noted geologists in an expedition to Spitsbergen,
of which some account was contributed to Nature (December 1, 1910)
and a description of a striking shelly moraine seen there to the
Proceedings of the Yorkshire Geological Society for 1911.

After the retirement of Mr. Horace B. Woodward, F.R.S., in 1908
the administrative work of Assistant Director of the Survey was
tuken up by Dr. A. Strahan, F.R.S., until his promotion to the
Directorship in 1914, when Mr. Lamplugh became Assistant Director.

In the latter year he made one of the distinguished band
of geologists who represented our science on the occasion of the
holding of the British Association in Australia (in August, 1914)

1 A paper read before the British Association for the Advancement of
- Science, meeting in South Africa at Johannesburg, August 30, 1905. See also
the Official Guide to the Falls, 1905, and the GEOLOGICAL MAGAZINE for
December, 1905, pp. 529-32.

342 Hminent Living Geologists—G. W. Lamplugh.

under exceptional facilities arranged by the Australian Governments.
Not long after their arrival in the Commonwealth came the serious
intelligence that war had been declared with Germany, a misfortune
which overshadowed the programme and marred the closing stage of
the meeting. Mr. Lamplugh was fortunately able, owing to the
kindness of officials everywhere, to see much of the country,
particularly in Western Australia, before the outbreak of war, under
the guidance of Mr. Harry P. Woodward and Professor Woolnough.

Mr. Lamplugh is “‘ no stranger in our midst”’, but is well known
and highly esteemed in the scientific world, having been a Geological
Surveyor for twenty-six years, and served upon the Councils of the
Royal Society (1914-16), the Royal Geographical Society, and the
Geological Society (1906-10, a Vice-President 1909-10, 1917),
and is now its President (1918). As a Yorkshireman he keeps up
his interest in all the amateur geological activities in the county.
He is a past-President of the Yorkshire Naturalists’ Union, the Hull
Geological Society, and the Hertfordshire Natural History Society ;
and is an Honorary Member of the Rhodesian Scientific Association,
the Yorkshire Philosophical Society, the Natural History and
Antiquarian Society of the Isle of Man, and the Nottingham
Naturalists’ Society.

One who has worked with G. W. Lamplugh in the field and on the
Survey and known him for some years writes :—

“Tf I were compelled to compress into three words my impression
of Lamplugh’s character, the ones I should choose would be courage,
determination, and consistency—the courage which spurred him to
break the current of his life and divert it to the work he loved and
knew he could do best; the determination with which he has
mapped out his career, passing through each objective to the next
and never allowing an opportunity or experience to pass by unused ;
and the consistent high purpose which has guided the quality of his
work, whether in the drifts, the Speeton clays, the Trias, or, that
fool’s paradise for geologists, the Isle of Man.

“These are the qualities which one sees in the field. A keen and
accomplished observer as any glacial geologist must be or become, he has
the elasticity of mind which enables him to turn to the discrimination
of obscure igneous or metamorphic rocks, to the determination of
ammonites or belemnites, or to the registering of those minute
features of landscape which tell the history of physiography. Only
here we must add the physical fitness for hard and steady work, and
the disciplined imagination which have made the story of the Zam-
besi, or the glacial history of the Isle of Man, read like a fairy tale.

“But it is when the day’s work is done and there ‘creep out the
little arts that please’ that we discover the man of wide reading
and liberal culture, of broad knowledge of places, men, and things,
of deep convictions and serious thought. Then, if not before, we
find the merciless critical faculty which takes nothing for granted,
the insight which looks down into the heart of things, and the
intolerance of sham and shoddy, which, seeking good in all, cannot
shut its eyes to the evidence that all is not always for the best.

‘« Although he has undoubtedly read the hundred best books he has

f
Eminent Inving Geologists—G. W. Lamplugh. 348

by no means neglected the others, and, bringing to bear upon his
great knowledge of literature, on its humane as well as its scientific
side, a delicate perception and a nice and balanced judgment, he has
become no mean judge of style and method. But the style that he
appreciates must be the embroidery that accentuates worth and
beauty and not that which is intended to hide deficiencies in both.
It was no small triumph to have detected a new de Rougemont who
had for the second or third time thrown dust into the eyes of those
whose business 1t was to see clearly in matters of style.

‘« Keen as is his evaluation of books, his knowledge of men is not less
well founded nor his judgment less sound. Having travelled far he
has made a wide circle of acquaintances of varied sympathies and
interests, and has met them under circumstances which favour close
intimacy. ‘To discuss men with him is as entertaining as to discuss
books, for he has studied the man as well as his work, has seen the
weak spots as well as the strength, and has the faculty of expressing
his opinions with a slightly malicious but always good-natured
humour which gives them a delightful if subacid flavour.

‘Tf one might be allowed three more epithets they would be—as
a geologist, sound; as a man, human; as a friend, lovable.”’

Mr. Lamplugh’s large knowledge and wide experience in our
science is always at the service of geologists who seek his kindly
help. He is without pretence and rather too retiring, but—as he is
only 59—that may be remedied as he grows older and has longer
intercourse with his fellow-hammerers. We offer him our sincerest
good wishes for his Presidency of the Geological Society, and he will
also carry our warm regard with him for the term of his natural life.

H. W.

GEOLOGICAL PAPERS OTHER THAN GEOLOGICAL SURVEY MEMOIRS.

1878. ‘‘ On the Occurrence of Marine Shells in the Boulder Clay at Bridlington
and elsewhere on the Yorkshire Coast’’: GEOL. MaG., Dee. II,
Vol. V, pp. 509-17.
1879. ‘‘On the Occurrence of Freshwater Remains in the Boulder Clay at
Bridlington’: ibid., Vol. VI, pp. 393-9.
1880. ‘‘On the Divisions of the Glacial Beds in Filey Bay’’: Proc. Yorks
Geol. & Polytech. Soc., vol. vii, pp. 107-17, 1879.
1881. ‘‘Ona Fault in the Chalk of Flambro’ Head, with some Notes on the
Drift’’: ibid., pp. 242-6, 1880.
**On a Shell-bed at the base of the Drift at Speeton, near Filey, on the
Yorkshire Coast’’?: GEOL. MaG., Dec. II, Vol. VIII, pp. 174-80.
“On the Bridlington and Dimlington Glacial Shell-beds’’: ibid.,
pp. 535-46.
1882-90. ‘* Glacial Sections near Bridlington,’’ pt.i: Proc. Yorks Geol. &
Polytech. Soc., vol. vii, pp. 383-97, 1881; pt. ii, ibid., vol. viii,
pp. 27-38, 1882; pt. iii, ibid., pp. 240-54; pt. iv, ibid., vol. xi,
pp. 275-300, 1889.
1883. ‘* Thornwick Bay, Flamborough’’: ibid., vol. viii, pp. 103-7, 1882.
1884. ‘Ona Recent Exposure of the Shelly Patches in the Boulder Clay at
Bridlington Quay ’’: Quart. Journ. Geol. Soc., vol. xl, pp. 312-18.
(Abstract in GEoL. MAG., Dec. III, Vol. I, p. 185.)
1886. ‘‘On Glacial Shell-beds in British Columbia’’: ibid., vol. xlii,
pp. 276-86 (ibid., Vol. III, pp. 233-4).
“* On Ice-grooved Rock Surfaces near Victoria, Vancouver Island, with
Notes on the Glacial Phenomena of the Neighbouring Region, and

344

1888.

\
Eminent Inving Geologists—G. W. Lamplugh.

on the Muir Glacier of Alaska’’: Proc. Yorks Geol. & Polytech.
Soc., vol. ix, pp. 57-70, 1885.

‘“Report on the Buried Cliff at Sewerby, near Bridlington’’: ibid.,
pp. 381-92, 1887.

“* Cliff Section at Hilderthorpe ’’ : -ibid., pp. 433-4, 1887.

‘*On a Mammaliferous Gravel at Hlloughton in the Humber Valley’? :
ibid., pp. 407-11, 1887.

1888-91. ‘‘On the Larger Boulders of Flambro’ Head,’’ pt.i: ibid.,

pp. 339-43, 1887; pts. ii and iii, ibid:, vol. xi, pp. 231-9, 1889;
pt. iv, ibid., pp. 397-408, 1890.

1888 (1891). ‘“Notes sur la géologie de Flamborough Head ’’: Explications

1889.

des Excursions, Internat.. Geol. Congr., 4th Session, Compte
Rendu, pp..389-407.

“On the Subdivisions of the Speeton Clay’’: Quart. Journ. Geol.
Soc., vol. xlv, pp. 575-618. (Abstract in GHoL. MaG., Dec. III,
Vol. VI, pp. 233-4.)

1889-91. ‘‘Reports of the Committee . . . investigating an Ancient Sea-

1890.

1891.

1892.

1891-2.

1894.
1895.

1896.

1896-7.

1898.

1900.

1901.

beach near Bridlington Quay’’: Rep. Brit. Assoc., 1888, pp. 328-38;
ibid., 1890, pp. 375-7.

‘On a New Locality for the Arctic Fauna of the ‘ Basement’ Boulder
Clay in Yorkshire’’: GEOL. MAG., Dec. III, Vol. VII, pp. 61-70.

‘“The Neocomian Clay at Knapton’’: Natwralist, 1890, pp. 336-8.

‘“ On the Boulders and Glaciated Rock-surfaces of the Yorkshire Coast ’’ :
Rep. Brit. Assoc., 1890, pp. 797-8.

“Hast Yorkshire during the Glacial Period’’: ibid., pp. 798-9.

‘“On the Drifts of Flamborough Head’’: Quart. Journ. Geol. Soce.,
vol. xlvii, pp. 384-431. (Abstract in GEOL. MaG., Dec. III,
Vol. VIII, p. 239.)

“The Flamborough Drainage Sections’’: Proc. Yorks Geol. & Polytech.
Soc., vol. xii, pp. 145-8, 1891.

(With Professor A. P. PavLow.) ‘‘Argiles de Speeton et leur
Equivalents’’: Bull. Soc. Imp. Nat. Moseou, N.s., vol. v,
pp. 181-213, 455-570 (also published separately, Moscow, 1892).
(Abstract in GEoL. MaG., Dec. III, Vol. IX, pp. 422-6.)

“Notes on the Snowfall of the Glacial Period’’: Glacialists’ Mag.,
vol. i, pp. 231-3.

“‘Notes on the Coast between Bridlington and Filey’’: Proc. Yorks
Geol. & Polytech. Soc., vol. xii, pp. 424-31, 1894.

(With W. W. Watts.) ‘‘The Crush Conglomerates of the Isle of
Man ’’: Quart. Journ. Geol. Soc., vol. li, pp. 563-97. (Abstract in
GEOL. MaG., Dec. IV, Vol. II, pp. 372-3.)

‘On the Speeton Series in Yorkshire and Lincolnshire ’’: ibid.,
vol. lii, pp. 179-218. (Abstract in GEoL. MaG., Dec. IV, Vol. TI,
pp. 87-8.)

““An Outline of the Geology of the Isle of Man’’: Handbook for
Lwerpool Meeting of British Association, pp. 165-81.

“Notes on the White Chalk of Yorkshire,’’ pts. i, ii: Proc.
Yorks Geol. & Polytech. Soc., vol. xiii, pp. 65-87, 1895; pt. iii,
ibid., pp. 171-91, 1896.

““Some Open Questions in East Yorkshire Geology’’: Trans. Hull
Geol. Soc., vol. iv, pp. 24-36.

‘‘ The Glacial Period and the Irish Fauna’’: Nature, vol. lvii, p. 245.

‘*On some Effects of Harth-movement on the Carboniferous Volcanic
Rocks of the Isle of Man’’: Quart. Journ. Geol. Soc., vol. lvi,
pp. 11-25. (Abstract in GEOL. MaG., Dee. IV, Vol. VII, p. 89.)

“Note on the Age of the English Wealden Series’’: GEOL. MAG.,
Dec. IV, Vol. VII, pp. 448-5. (Also in Rep. Brit. Assoc., 1900,
pp. 766-7.)

‘* Names for British Ice-sheets of the Glacial Period’’: ibid., Vol. VIII,
p. 142.

1903.

1904.

1905.

1905-6.

1906.

1907.

1910.

1911.
1912.

1913.

1886.
1897.

1902.
1906.

1908.

Eminent Living Geologists—G. W. Lamplugh. 345

‘“Belemnites of the Faringdon ‘Sponge-gravels’’’: ibid., Vol. X,
pp. 32-4.

(With J. F. WALKER.) ‘‘On a Fossiliferous Band at the top of the
Lower Greensand near Leighton Buzzard (Beds)’’: Quart. Journ.
Geol. Soe., vol. lix, pp. 234-65. (Abstract in GEOL. MAG., Dec. IV,
Vol. X, p. 137.)

‘‘Land-shells in the Infra-glacial Chalk-rubble at Sewerby, near
Bridlington Quay ’’: Proc. Yorks Geol. & Polytech. Soc., vol. xv,
pp. 91-5, 1903. (Abstract in GEOL. MaG., Dec. IV, Vol. X, p.513,
and Rep. Brit. Assoc., 1903, p. 659.)

‘On the Disturbance of Junction Beds from Differential Shrinkage and
similar local causes during Consolidation’’: Rep. Brit. Assoc.,
ayn 666. (Also GEoL. MAG., Dec. IV, Vol. X, pp. 516-17,
1903.

**Note on the Conditions of Accumulation of the Yorkshire Chalk,
as shown by the State of Preservation of the Fossils’’ (Appendix
C to Paper by A. W. Rows): Proc. Geol. Assoc., vol. xviii,
pp. 287-9.

‘“ Note on Lower Cretaceous Phosphatic Beds and their Fauna’’: Rep.
Brit. Assoc., 1904, p. 548. (Also GEoL. MaG., Dec. V, Vol. I,
pp. 551-2, 1904.)

““Notes on the Geological History of the Victoria Falls’’: GEOL.
MaG., Dee. V, Vol. II, pp. 529-32. (Reprinted from ‘‘ The
Official Guide to the Victoria Falls’’, by F. W. SYKEs.)

‘“Report on an Investigation of the Batoka Gorge and adjacent
portions of the Zambesi Valley’’: Rep. Brit. Assoc., 1905,
pp. 292-301. (Also Nature, vol. lxxiii, pp. 111-14, 1905.)

“On British Drifts and the Interglacial Problem’’: Presidential
Address to Section C of British Assoc. York. Pamphlet, 1906;
also Nature, Ixxiv, pp. 387-400, 1906, and Rep. Brit. Assoc., 1906,
pp. 532-58, 1907.

““Geology of the Zambezi Basin around the Batoka Gorge’’: Quart.

. Journ. Geol. Soc., vol. lxiii, pp. 162-216. (Abstract in GEOL.
MaG., Dec. V, Vol. IV, pp. 138-40.)

‘‘ Estuarine Shells in the Alluvial Hollow of Sand-le-mere, near
Withernsea in Holderness’’: Naturalist, January, pp. 7-11.

“Notes on British Late-Glacial and Post-Glacial Deposits’’: Die
Verdnderungen des Klimas, etc. (Geol. Congr.), Stockholm, 1910,

p. 49-54.

‘“On Movements in Rocks’’: Presidential Address to Herts Nat. Hist.
Soc., Naturalist, May, pp. 180-3.

““On the Shelly Moraine of the Sefstrém Glacier and other Spitsbergen
Phenomena illustrative of British Glacial Conditions’’: Proc.
Yorks Geol. Soc., vol. xvii, pp. 216-41, 1911.

“* The Interglacial Problem in the British Islands’’: Internat. Geol.
Congr. Toronto, XII Sess., Compte Rendu, pp. 427-34.

GEOGRAPHICAL AND GENERAL PAPERS AND ESSAYS.

““Notes on the Muir Glacier of Alaska’’?: Nature, vol. xxxiii,
pp. 299-301.

‘* Geologists in Canada (Journey of British Assoc. party from Toronto
to Vancouver Island) ’’: ibid., vol. lvii, pp. 62-6.

‘““ Geology of Surrey ’’: Victoria County History of Surrey, vol. i, ch. i.

““Notes on the Occurrence of Stone Implements in the Valley of the
Zambesi around Victoria Falls’: Journ. Anthrop. Inst., vol. xxxvi,
pp. 159-69.

““On, the Necessity for the Amateur Spirit in Scientific Work’’:
Presidential Address to Yorkshire Nat. Union, Natwralist, March,
pp. 71-80.

‘“The Gorge and Basin of the Zambezi below the Victoria Falls,
Rhodesia’’: Geogr. Journ., vol. xxxi, pp. 183-52, 287-303.

346 8D. Balsillie—Hypersthene Andesite, Fifeshire.

1908. ‘‘ Geology of Kent’’: Victoria County History of Kent, vol. i, ch. i.
1909 & 1914. ‘* Physiographical Notes. I. On Hrosive conditions resulting
from Snowfall’’: Geogr. Journ., vol. xxxiv, pp. 56-9. II. “‘On
the Taming of Streams’’: ibid., vol. xliii, pp. 651-6.
1910. ‘‘Man as an Instrument of Research’’: Presidential Address to the
Herts Nat. Hist. Soc., Naturalist, May, pp. 187-98.
** Stockholm to Spitsbergen: The Geologists’ Pilgrimage’’: Nature,
vol. Ixxxv, pp. 152-7.
1914. ‘‘ The Isle of Man’’: The Oxford Survey of the British Empire: The
British Islands (Clarendon Press), ch. xx, pp. 498-510.
Also numerous review-articles, letters, etc., on geological and geographical
subjects, in GEoL. Maac., Nature, Geogr. Journ., etc.

GEOLOGICAL SURVEY MEMOIRS, PUBLISHED BY H.M. STATIONERY OFFICE.

1903. Geology of the Isle of Man (with Petrology by Professor W. W. WATTS,
M.A., F.R.S.). 8vo. pp. xiv + 620, with 5 pls. and 110 text-figs.
Cloth, 12s.

1910. Geology of the Country around Nottingham (with W. GrBson). 8vo.
pp. 72, with 7 pls. and 9 figs. Wrapper, 2s.

1911. The Mesozoic Rocks in some of the Coal Explorations in Kent (with
F. L. KitcHIN). 8vo. pp. 212, with 5 pls. and 5 figs. Wrapper,
3s. 6d.

1914. Water Supply of Nottinghamshire (with B. SMITH). S8vo. pp. 574,
2 coloured maps, and 2 figs. Wrapper, 5s.

1917. Summary of Progress for 1916: Appendix III, On a Deep Boring at
Battle ; App. IV, The Underground Range of the Jurassic and Lower
Cretaceous Rocks in Kast Kent, pp. 40-52.

CONTRIBUTIONS TO THE FOLLOWING SHEET MEMOIRS.
1899. Geology of the Borders of the Wash.
1903. Geology of the Country around Chichester.
Geology of the Country around Dublin.
1904. Geology of the Country around Belfast.
1905. Geology of the Country around Cork and Cork Harbour.
Geology of the Country south and east of Devizes.
1907. Geology of the Country around Limerick.
1908. Geology of the Country between Newark and Nottingham.
Geology of the Country around Oxford.
1909. Geology of the Melton Mowbray district and 8.K. Nottinghamshire.
1911. Geology of the Country around Ollerton.
1913. Geology of the Northern Part of the Derbyshire Coalfield, etc.
1915. Geology of the Country between Whitby and Scarborough, 2nd ed.

IIl.—Nore on a HyprrstHene ANDESITE FROM PitcuLio, FIFEsHIRE.
By D. BAusILuiz, F.G.S., Chemistry Department, University of Edinburgh.

(T\WENTY-ONE years ago Dr. Flett in a valuable paper (Trans.

Edin. Geol. Soc., vol. vii, 1897) described an exceedingly
beautiful hypersthene andesite from the volcanic series of the Lower
Old Red Sandstone at Dumyat in the Western Ochils. In the
following brief communication I propose to give a short petrographic
account of a strikingly similar rock that has occurred to me in the
field in a more easterly portion of the same range of hills and which
is of the same geological age.

In East Fife the volcanic rocks of the Lower Old Red Sandstone
rise abruptly above the southern shores of the Firth of Tay. They
consist here as elsewhere of lavas, tufts, voleanic breccias, and
agglomerates, with intervening belts of sediment that no doubt

D. Balsilie—Hypersthene Andesite, Fifeshire. 347

marked intervals of quiescence more or less prolonged in the course
of their voleanic history. ‘lhe prevailing dip of the rocks is towards
south-east, so that as we proceed in that direction progressively
higher members of the sequence are encountered. As usual among
the igneous products of this geological period, the most abundant
extrusive types are andesites. More acid rocks, such as felsites, also
oecur, but there is no evidence to prove conclusively that in the area
in question these are ever true lavas. (Reference may here be made
to the salmon-pink felsite of Lucklaw Hill, which has hitherto been
regarded asa lava. The enormous extension of this mass at right
angles to the general strike of the rocks and the manner in which it
sends ramifications into the andesites that surround it, especially on
its. northern boundaries, point only to one conclusion, viz. an
intrusive origin.) The andesites vary greatly in their physical
characters. Some are slaggy, having abundant mineral-filled
vesicles, others being thoroughly compact with a platy system of
joints and an occasional development of brecciation along their lower
portions. These latter compact rocks afford excellent material for
microscopic investigation, and as in many cases they have been laid
bare in quarries for the provision of material to macadamize the
public roads it is not difficult to collect representative examples of
the fresher types of the district. It is in reference to a fortunate
exposure in one of these artificial openings that this note has been
written, and the remarks that follow are based entirely on the
examination of rock specimens collected from one locality, viz. near
Pitcullo in East Fife.

Inspection of a 1 inch to the mile topographic map of Fifeshire
will show that on the main road between the county town of Cupar
and Dundee there is, about 1 mile to the north-east of the little
village of Dairsie, a farm steading named Muirhead, from which point
a road runs west across the hills towards Craigsanquhar. Less than
half a mile along this road from the junction just mentioned, and
immediately on its right-hand side, a quarry has been opened among
the lavas. The main rock of the quarry, which is situated at no
ereat distance from the mansion house of Pitcullo, and is con-
sequently designated the Pitcullo Quarry, is not of such character as
to attract any special attention, but high on the worked face, on the
side remote from the road, a rock of remarkable freshness and with
a pitchstone-like resinous lustre occurs. It is coated externally with
a light-brown crust, perhaps as much as a quarter of an inch in
thickness, but beneath this weathered zone is very black and
compact, and shows on a freshly broken surface abundant porphyritic
crystals of a glassy felspar. There is no line of demarcation between
this fresh rock and that lower in the quarry face, and the probability
is that it is merely a modification of the rock occurring there.

Under the microscope confirmation of the fresh nature of the rock
is immediately to be obtained. It consists of a remarkably homo-
geneous, brown in colour, isotropic groundmass, in which are
disposed numerous porphyritic crystals of glassy felspar, ortho-
rhombic and monoelinic pyroxenes, as well as irregular grains and
granules of magnetite.

348 D. Balsillie—Hypersthene Andesite, Fifeshire. .

The porphyritic felspars, which in many cases are beautifully
zoned, belong to the albite-anorthite series and exhibit albite,
carlsbad, and pericline twinning. They are often elongated along
the crystal axis a, but are sometimes also equidimensional on the
second pinacoid. Examination by Fouqué’s method shows that in
sections normal to the bisectrix there is an angular divergence
between the trace of the optic axial plane and (010) of 64°, the
corresponding extinction angle on slices perpendicular to y, measure-
ment being made to the (001) cleavages, amounting to from 20° to
24°, these values agreeing well with an acid labradorite. Confirma-
tion of this identification can be readily obtained from sections that
exhibit both carlsbad and albite twinning by the well-known method
of Michel Lévy, as also from slices cut normally to (010) and (001).
The felspar phenocrysts are much more abundant than in the Dumyat
rock, are equally fresh and unaltered, and as in its western counter-
part the felspars here often contain glass inclusions and show
evidence of resorption, though this phenomenon is not nearly so
marked as in the rock described by Dr. Flett. Neither is there here
the same indication of flow structure, the phenocrysts in the field of
the microscope not showing the rough parallelism that immediately
strikes one in the Dumyat rock. As noted, the felspar crystals are
often elongated along the crystal axis a, and a single Baveno twin
was observed cut almost normally to the bisectrices a, the two
halves giving angles of 60° and 61° respectively between the optic
axial plane and (010). Each half was in addition twinned on the
albite law, and an albite lamella in the one half was seen to be con-
tinued across the composition face and be prolonged in the other
individual on the pericline law. ‘his optical distinction could easily
be made out under high magnification and making use of a thin
gypsum plate.

The pyroxenes include, as has been said, both orthorhombic and
monoclinic varieties. The former mineral, which predominates, is
optically negative, markedly pleochroic, and may safely, I think, be
taken as hypersthene. The crystal outlines are well-marked sections
transverse to the crystal axis c, being rectangular in form, with
the prism faces occurring as mere truncations of the corners. Such
sections are invariably traversed by a set of irregular cracks, in
addition to which there is a well-developed prismatic cleavage. -
A pinacoidal cleavage I did not observe. The hypersthenes are
usually quite fresh and have a tendency to occur as little coteries of
small crystals, sometimes in association with the monoclinic pyroxene
or in other places along with the felspars. The pleochroism is as
follows: X pale reddish-brown, Y pale yellow, Z green.

The monoclinic pyroxene is at once to be distinguished from the
hypersthene by its oblique extinetions and higher interference
colours. The dark borders that were noted by Dr. Flett to surround
the augites in the Dumyat rock do not occur here. ‘The crystal
outlines are but ill defined, and twinning occurs on one or more laws
that I did not determine. The mineral is not pleochroic, and on the
prismatic zone of faces exhibits very often roughly parallel cleavage
traces. The angle between the bisectrix Z(=y) and (100) was

D. Balsillue—Hypersthene Andesite, Fifeshire. 3849

found to amount from 40° to 45°, this corresponding with augite,
which I therefore take to be the monoclinic pyroxene present.

Magnetite occurs disseminated as quadrangular and irregular
grains throughout the rock, and is frequently enclosed in the
pyroxenes. Apatite such as occurs in the Dumyat and Cheviot
andesites I did not observe.

The groundmass of the Pitcuilo rock examined under low powers
appears remarkably isotropic, but is resolvable under higher
magnification to a mass of little felspar crystals that le in an
ultimate base of pale-brown or colourless glass with globulites. In
addition to the felspars, which are twinned on the albite law and
have only a small extinction angle, a second generation of pyroxenes
also occurs, Magnetite, too, is an abundant constituent.

In sections of the Dumyat rock a number of lighter areas made up
of minute microlites and having a darker periphery were observed
by Dr. Flett. In their most perfect form these occur ‘‘as rounded
bodies which have some resemblance to spherulites’”’. Such circular
ageregations of microlites I have not noted in the Pitcullo rock,
though irregular areas of a similar kind, and often with a darker
border, not uncommonly oceur. Comparison, however, with hand-
specimens of the typical kugel andesite from Bath, Hungary,
convinces me that it would be quite unwise to describe kugel
structure as occurring in the Pitcullo rock. The Hungarian rocks
have had a sort of pseudo-amygdaloidal structure conferred upon
them by the physically separable character of their kugels. This
certainly is not the case in the rock from Kast Fife.

The rock that has now shortly been described is by far the freshest
typical andesite that I know in the district in which it occurs.
It is not, be it at once said, quite so glassy as the exceptionally
fresh rock from Dumyat, but in the best specimens is only a little
less so.

The bulk of the material in the quarry consists, as has been
indicated, of hypersthene andesite, but is really a rock quite
different in appearance from that described in the foregoing notes.
It is grey in colour, is obviously in a much less fresh condition, and
suggests Im no way, macroscopically at all events, relationship with
the fresh ‘‘ pitchstone”’ that comes on top of it. Notwithstanding
this physical distinction, both appear to have belonged to the same
parent mass. Under the microscope the felspars can be seen to be
equally clear and glassy and to have an identical composition. Both
orthorhombic and monoclinic pyroxenes occur, as in the unaltered
rock, the former, however, now only represented by pseudomorphs
made up of strongly absorbing fibres. Impregnations and veins of
iron oxide are frequent, obscuring totally in some slices the real
nature of the rock that carries them. The base is much less glassy,
and the felspars of the second generation are larger. It will there-
fore be seen that any distinction that occurs may only be due to
differences in the cooling history of the two portions of the rock and
to the fact that the glassy rock by virtue of its compactness has had
conferred upon it a higher degree of resistance to the agencies of
secondary change.

350 R&R. M. Brydone—The Belemnitella mucronata Zone.

Being interested as to the chemical nature of the unaltered
andesite, Mr. R. K. 8S. Mitchell, one of the senior workers in this
laboratory, kindly undertook to carry out for me a determination of
the silica and bases present, which he did under the supervision of
an exceedingly skilled analyst, my friend Dr. Sidney A. Kay.
Mr. Mitchell’s figures are as follows :—

Si O2 6 : , : : : . 61:37
AleOs : 3 ; ; : . 18-80
Fee Os 5 c 6 dl 6 6 5-46
Mn O ‘ : : ; : 3 : —
CaO F Gents : P ; ; 5-62
IMO ee cau oaths 0) cutee rien yak os biel ba mone
Nas O - 5 5 . . 5 6 3-83
K,0 : : : : : : : 2-05
99-01

Comparison of these results with the analyses given by Sir Jethro
‘Teall in his valuable papers on the Cheviot andesites (GrozLoeicaL
Magazine, 1883) will at once show in what striking fashion there is
chemical similarity between the Old Red “‘ pitchstone porphyrites ”’
of the borders and the example described above from Kast Fife.

In conclusion, it is my duty to express very cordial thanks to
Professor James Walker, F.R.S., for having added to the equipment
of this Department several items of optical apparatus which have
enabled me to carry out the foregoing mineral determinations.

IJ].—Tue TricknEess oF THE ZonE oF BELEMNITELLA MUCRONATA
In THE IstE or Wicut.

By R. M. BRYDONE, F.G.S.

N 1908 Dr. Rowe published an account of the Chalk of the Isle of
Wight! with a zonal map in which the zone of Belemnitedla
mucronata was shown as entirely absent at some points but generally
present in substantial thickness. At the two ends of the island
actual measurements were made, of 150 feet at Culver Down and
475 feet at the Needles. How much of the latter thickness was
measured in the cliffs and how much is made up of somewhat less
satisfactory measurements at low tide on weed-covered reefs is not
clear, but at any rate there must be well over 300 feet in the cliffs.
This figure is sufficient to show how great a ravining of the
pre-Tertiary surface of the chalk would be required for the repeated
disappearances of the zone as mapped. It seems justifiable to pay
some critical attention to the evidence on which such a state of
things is alleged.

It will be found on reference to the map in question that there
are five points at which the zone of Belemnitella mucronata is repre-
sented as disappearing completely, while in between them it swells
out each time to a very substantial thickness. (I do not include the

1 “The Zones of the White Chalk of the English Coast. V. The Isle of
Wight’’: Proc. Geol. Assoc., vol. xx, pt. iv, p. 209.

R. M. Brydone—The Belemnitella mucronata Zone. 351

case at the east end of ‘apnell Down, as this is probably due to the
combined effect of an imperfect junction between the sections and of
exigencies of space leading to the exclusion of part of the chalk
area.) Of these five cases, two appear to be arrived at by assumption
only, but three are connected* with paleontological evidence from
sections and will be considered first.

The most interesting of these is undoubtedly the one just west of
Freshwater by pit 11 (Rowe), for, as Dr. Rowe points out, it is but
2 miles from Alum Bay with its great thickness of mucronata chalk.
The paleontological evidence given by Dr. Rowe is that the shells in
the pit are white, and that two examples of Hehinocorys of quadratus
type were found. The former statement does not seem to have any
bearing on the question unless it is established that no white shells
are to be found in the lower mucronata chalk of the Isle of Wight.
I know of no authority for such a proposition, and it is not in accord
with any experience of mine, although Mr. Griffith and I long ago
noted redness in the shells as a feature of the upper beds of the
mucronata chalk. The phrase ‘‘ Hchinocorys of quadratus type”’
conveys no meaning to me. No shape of Echinocorys typical of
upper qguadratus chalk has, so far as I know, been defined in any
way by Dr. Rowe, much less one which while typical of quadratus
chalk cannot be found in low mucronata chalk, and only such a form
would be of any value for assigning a section to the former zone to
the exclusion of the latter. Even if such a form had been defined
and definitely recognizable specimens found in this pit they» would
prove very little. All probability is in favour of Hchinocorys recorded
from this pit having been found on the extensive talus, the surface
of which is obviously derived from the chalk high up at the back of
the pit. In ordinary horizontal or slightly inclined chalk the
identification of the guadratus zone at the top of a pit close to the
Tertiary boundary would afford a strong presumption that no
mucronata chalk was preserved at that point. But the Isle of Wight
chalk is nearly vertical, and therefore the identification of the
quadratus zone at the top of this pit—as to the accuracy of which
I do not suggest any question, it having also been made by
. aves the whole thickness
between the back of the pit and the Tertiary boundary, a distance
of some 120 feet, corresponding to a thickness of at least 100 feet
of chalk, open to reference to either the qguadratus zone or the
mucronata zone. To carry the matter a step further, even if an
absolutely decisive Echinocorys were found at the most northerly
point where chall is still exposed in the pit, there would still
remain between that point and the Tertiary boundary some 30 feet
of chalk, and this could not be ruled out of the mucronata zone on
any paleontological ground.

As a matter of fact, there is some slight positive ground for
holding the view that the mucronata zone is exposed within the pit.
There is now a sideway extension, which I do not remember in the
nineties, cut parallel with and close to the footpath, and some of the
chalk exposed here is gritty and hard, contrasting rather sharply
with the soft and fine-grained chalk at the back of the pit. I have

352 Rk. M. Brydone—The Belemnitella mucronata Zone.

recorded precisely this contrast between the guadratus and mucronata

chalk in Portsdown as separated on paleontological evidence.!
_ The second point at which paleontological grounds are quoted in
support of the view that the mucronata chalk has been wholly
removed is pit No. 3 (Afton Down). Here the position corresponds
almost exactly with that at pit No. 11. There is a pit in which the
presence of the quadratus zone is established by paleontological
evidence, as Mr. Grifiith and I recognized in the nineties; but the
principal face and talus, from which this recognition was made, are
at the back of the pit, some 80 feet from the Tertiary boundary.
The chalk towards the mouth of the pit seems of different character
from that at the back, and in it I have found what appears to be
a broken specimen of Vhecidea Brydoner, which is only known from
the basal mucronata chalk of Portsdown. Here, again, there is
nothing in the evidence cited by Dr. Rowe to warrant the statement
that the quadratus zone extends to the mouth of the pit, much less
to the Tertiary boundary; and there is some suggestion of evidence
to the contrary.

As zonal indications are so scarce, it is perhaps worth mentioning
that it was in this pit that I found the type of Membraniporella
Gabina® many years ago on the talus, but in what_part of the pit
I cannot say for certain. I naturally attributed it to the zone
undoubtedly represented in the pit, that of A. qguadratus. At the
time of describing the species 1 had only two other specimens, one
a very doubtful one from the floor of this same pit near the mouth
aud one from the zone of B. mucronata at Portsdown. I have since
recognized several other specimens all from indisputable mucronata
chalk either in the Isle of Wight or at Portsdown. I think there is
some justification for the view that this species, which has never yet
been found in undotibted quadratus chalk, actively as the top beds of
that zone have been exploited in Hants, is restricted to the mucronata
zone, and has only been found in this pit because chalk of that zone
is or has been exposed in it.

The third place at which the zone of B. mucronata is represented
on paleontological evidence as entirely removed is at Ryde Water-
works (pit No. 45). Here we may remark, as in the two previous
eases, that the critical section does not extend to the Tertiary
boundary by some 90 feet, and cannot therefore afford evidence as
to the nature of the chalk in contact with the Tertiaries. Kven for
the alleged quadratus horizon of the section itself the paleontological
evidence given by Dr. Rowe is very scanty and purely negative, and
scanty negative evidence can hardly form a satisfactory basis for the
assertion of an exceptional state of things. In this case again there
are grounds for doubting the reference of, at any rate, the whole of
the section to the quadratus zone. The barrenness of the chalk is
not in the least exaggerated by Dr. Rowe, but I have found on the
talus below the section a small damaged Hehinocorys likely to be the

' The Stratigraphy of the Chalk of Hants, p. 8 (London, Dulau & Co.,
1912).
2 GEOL. MaG., 1917, p. 494, Pl. XXXII, Fig. 8.

Rh. M. Brydone—The Belemnitella mucronata Zone. 353

var., subconicus characteristic of the mucronata zone. If this zone
occurs at all in the section, there would be room for a minimum
thickness of some 80 feet of it. :

The two places at which no paleontological grounds are given for
cutting out the mucronata zone altogether are at Burnt House (north
of Garretts) and at the west end of Bembridge Down. It will be
obvious on inspection that these disappearances of the zone are due
solely to the thicknesses assigned to the other Upper Chalk zones
exhausting all the available space between the Chalk Rock and the
Tertiary boundary as mapped. These thicknesses appear at the
points in question to be purely arbitrary; indeed, at the end of
Bembridge Down the quadratus zone seems to have been deliberately
given a special local increase of thickness but for which some
mucronata chalk must have been shown at that point. Unexpected
results obtained by such free methods of mapping seem to be much
in need of testing before any authority is claimed for them. The
prospect of being able to apply any test (except by making a special
excavation) are naturally very small if Dr. Rowe found no exposure

Fie. 1.—Tracing of a very small portion of a folding map (plate D), marked
on map “‘ Garretts to Arreton Down ’’ as ‘‘ Downend Chalk Pit (21) ’’ on
Gallows Hill. Illustrating Dr. Arthur W. Rowe’s paper on ‘‘ Zones of
the White Chalk of the English Coast’’, part v, ‘‘'The Isle of Wight ”’
(see Proc. Geol. Assoc., vol. xx, pt. v, p. 209, 1908).

at these points, but it so happens that in one of the cases I have been
able to do so and to obtain a result. At Burnt House I recently
detected a low face of massive chalk about 6 feet behind the out-
buildings (a shed with pigstyes at the back) shown on the map. In
this face I was fortunate enough to find a specimen of Belemnitella
mucronata and a small Hehinocorys, which, although too much crushed
for any certainty, appeared likely to be the var. subconicus. his
evidence is sufficient justification for definitely identifying the
mucronata zone at this point, which is about 150 feet from that zone
as mapped. Ifthe upper boundary of the quadratus zone be rectified
to this extent (and it may well be that a more extensive rectification
is due), it will at once be clear that only an improbable disturbance
would carry the quadratus zone up to the Tertiary boundary just
west of Burnt House, as is represented. The same rectification
would presumably have to be madein the Marsupites plus Uintacrinus
zone, and this would cancel the arbitrary expansion which has been
given to the coranguimum zone at this point.

It therefore seems as if no reliance can be placed on the fluctua-
tions of these zonal boundaries except where they are based on the

DECADE VI.—VOL. V.—NO. VIII. 23

354 Sir H. H. Howorth—Geological History of the Baltic.

evidence of sections. They do not appear to be drawn with due
attention to all available facts. They sweep across the deep valleys
-in the Upper Chalk indicated by the contour-lines at e.g. Burnt
House or Standen Copse without any deviation. This could only be
truthful in vertical chalk, and there is no ground for supposing that
the chalk is vertical in these valleys though inclined in all sections.
Even direct evidence from sections is liable to be ignored, as can be
readily seen in the case of the great Downend pit. In Fig. 1 there
is reproduced the rough outline of the pit. There is a high con-
tinuous face along the line a 6 c, while the line d e marks the
strike as mapped for Dr. Rowe. If this strike is correct the highest
chalk exposed in this face would be at the point 6, and from 6 to ¢
there would be a repetition of some of the beds exposed from a to 6.
This is, however, not the case. There is no repetition from 6 to ¢,
but a gradual passage to higher chalk. The strike must therefore be
at least as nearly EK. and W. as the dotted line fg, and such a strike
calls for zonal boundaries in this neighbourhood of a trend differing
substantially from that given to them in the map and inconsistent
with the thinning of the mucronata zone shown. (Incidentally I may
say that close to the point 6 I have been able to identify the top bed
of the upper band of Offaster pilula in the subzone of abundant
Offaster pilula by its usual physical characters and large form of
O. pilula. In downward succession from e to a there is first chalk
without any marl seams. Below the first marl seam met with there
are roughly 32 feet of chalk containing seven marl seams, and then
come the two marl seams, 3 feet apart, with a flint line between
them, which enclose this top bed.)

In the face of the foregoing considerations it is hardly possible to:
accept it as established that the mucronata zone has been entirely
denuded away at any point in the Isle of Wight, and much of the
alleged variation of that zone in thickness from point to point seems
to rest upon a very insecure basis.

TV.—Tue Recent Grotocicat History oF tHE Bartic anp ScanptI-
NAVIA AND ITS IMPORTANCE IN THE Post-Trrtiary History oF
WestERN Europe. -

.By Sir Henry H. Howorta, K.C.1.E., F.R.S., F.S.A., F.G.S.

Part I. ;
OME years ago I was allowed to publish in the Groroetca
\) Macazine? some papers on the recent geological history of the

Baltic, in which I tried to bring before English readers the very
important discoveries of the Northern geologists as affecting the
general geology of the north-west of Europe and to extend their
deductions. I was obliged to interrupt them for other work.
Perhaps you will allow me to continue them some steps further, as we
had reached a stage of some interest.

The northern portion of the Baltic, generally known as the:
Bothnian Gulf and comprising an area of over 1,877 square miles,

1 For previous communications on this subject, see GEOL. MAG., Dee. II,
Vol. II, pp. 311, 337; Vol. III, pp. 1, 550.

Sir H. H. Howorth—Geological History of the Baltic. 355

is formed of two ovals separated by a narrow stricture between the
towns of Umea in Sweden and Vasa in Russia, where the Archipelago
of Quarken is situated. The more northern of these ovals, with an
area of about 662 square miles, is known to the Swedes as Botten-
viken, while the southern one, with about 1,215 square miles, is
known to them as Bottenhavet. The former is now virtually a fresh-
water inlet. It contains but one living marine mollusc, and this
only in its extreme southern part, namely, Dacoma solidula= Tellina
Balthica, which Nordquist reports from lat. 63:52 N.

As we have seen in previous papers, the latest raised beaches all
round the coast of the Bothnian Gulf, including those at its head, prove
that before the last changes of level took place in its shores there were
four marine molluses living there which have all now migrated further
south, owing to the sweetening of the waters, caused largely by the
inflow of the rivers having dominated that from the North Sea. —

The reduction of the salinity may be measured by the fact that
two of these molluses, Litorina litorea and L. rudis, are both
very adaptable littoral shells, seldom found at a greater depth
than the low-water mark of spring tides, and often in large numbers
in hollows of the rocks above the highest tides. Gwyn Jeffreys
found the former living on the shore in a stream of perfectly fresh
water during the recess of the tide (Br. Moll., 11, 106). The latter
is often found in places overflowed by freshwater streams during the
recess of the tide with its companions, the common mussel and the
limpet (ibid., 11, 267). This means that they can live where
the water is at one time fresh and at another salt, but not where, as
in the Bothnian Gulf, the percentage of salt is always very small.

Both species occur in the lower raised beaches of the Baltic, and
Litorina rudis has been found in them at Neder Kalix at the very
head of the Bothnian Gulf. From them, as characteristic shells,
these beaches have been called Litorina beaches, and the Baltic, at
the time when they formed its margins, has been named the Litorina
sea. In their strict sense the Zitorina sea and the Litorina period
came to an end when the uplifting of its bed and borders led to the
shrinkage of the water from the area marked out by the Litorina
beaches to its present contour. The change was limited to the
restriction of its area and the re-arrangement of the range of dis-
tribution of its living contents, otherwise the ZLitorina sea had
a continuous life with the present Baltic. This I have tried to show
was not the result of a gradual change of level but of a spasmodic one.

The present conditions in regard to salinity and the present
distribution of the mollusca, in the latitude of Bornholm represent
very nearly what these elements were at the head of the Bothnian
Gulf in the Litorina time.

As I pointed out in the second paper of this series, the Litorina
sea was the successor of a great freshwater lake whose limits
are marked out by the wpper beaches of the present Baltic, and
which contain no debris of marine life but only freshwater remains.
From a notable shell the lake contained, it has been called the
Ancylus lake or sea, which in turn gave its name to the Ancylus
period. All this is now universally accepted and has been amply

©

SHO: | sie Jel, Jak Howorth—Geological History of the Baltic.

proved by the researches of the Northern geologists, notably Schmidt,
De Geer, Munthe, Holst, and Nathorst.

There is also a complete agreement among them that the cause of
the conversion of the freshwater Ancylus lake into the Litorina sea
was the breaking down of the land barrier which once united
Southern Sweden with Pomerania and Mecklenburg on the one hand
and Jutland on the other, and the opening of the three channels
known as the Oresund, or Sound, and the Great and Little Belts by
which the salt water of the North Sea first got access to the then
enclosed freshwater Baltic, and converted it into a more or less
brackish sea. This I have tried to show was not the result of the
slow and gentle operation of current and normal denuding causes, but
of a violent and sudden or very rapid dislocation of the earth’s crust.
It is necessary again to emphasize the difficulties of the opposite
view, and the more so since I am constrained to believe that the
dislocation was far greater, more wide-spread and important than
has hitherto been thought.

The opposite view is really based on a professed adhesion to the
theory of uniformity which is held to be inconsistent with catastrophe.
Not uniformity in the sense that Nature working with the same tools
and with the same potency and speed produces similar results, which
is the keystone of modern science, but that Nature’s operations at all
times have been the same both in kind, potency, and rapidity as
those which are working at this moment. ‘This view, which
still prevails with some geologists, is contradicted by all the
evidence now ayailable, notably by the gigantic and quite abnormal
phenomena of the great mountain chains.

Let us, however, turn to our immediate problem and see what the
evidence is.

First, we have the notable fact which, after a long discussion,
seems to be now generally received, namely, that in Sweden, as in
Britain and (as I shall point out presently) in Norway, there is no
reliable evidence that the relative heights of land and water have
altered in any appreciable way for a very long time, probably not for
2,000 years. This is also notably true of the Cattegat and the three
waterways between it and the Baltic. In the case of the Cattegat,
as in its gulf the Limfiord, the position of the kitchen middens in
reference to the sea-level is an excellent test. In that great inlet
which is girdled with these refuse heaps of primitive man, there is
clear evidence that only slight changes have taken place in the
relative position of the middens to the sea-level since the earliest
stage of the Stone Age of Scandinavia. In the Sound and Belts the
only notable changes have been those of silting up of estuaries and
river channels, and of certain small signs of elevation (to which we
shall refer presently). On the other hand, the position of the old
maritime villages and towns, castles, and large trees on the sides of
the waterways, both in Western Sweden and Denmark, are conclusive
that there has been no upheaval or subsidence here for a long time,
and no widening of the channels by denuding causes. In the case of
the Sound we have a remarkable piece of evidence emphasizing this
conclusion.

Sir H. H. Howorth—Geological History of the Baltic. 357

The island of Saltholm is planted in the very middle of the
Channel. It is only raised a very few feet above the water,
- and is mentioned in the thirteenth century as a source of income to
the Chapter of Roeskilde (see Geol. Proceedings, xi, 555), showing
that there cannot have been much, if any, alteration there for many
centuries. Nor, indeed (if we follow the teaching of rational
uniformity), can we understand how, in a virtually tideless sea like
the Baltic, the water could ever have had such potency as to bore
through these channels.

In the present case we haye no room for a draft on unlimited time,
a favourite appeal of many geologists (who pursue deductive and not
inductive methods), because, as has been pointed out by the Danish
archeologists and geologists, the channels between the islands did
not exist when the kitchen middens were laid down (see pt. 111 of
these papers, p. 12, etc.).

These arguments can be supplemented by others; thus, if the
substitution of the Zitorina sea for the Ancylus sea had been due to
the gradual opening of the Baltic channels, we ought to have had
a mixing and overlapping of the faunee of the Ancylus and Litorina
seas, which is not the case, but there is a complete gap between the
two sets of deposits. On the other hand, it is virtually certain that
the outpouring of fresh water from the Baltic, which, as we have seen,
killed the oysters, Zapes, and other molluscs in the Cattegat, was not
a gradual process. If it had been so we ought to have some evidence
in the kitchen middens themselves, where the shells ought, under _
this maleficent influence, to have gradually become dwarfed and
distorted, as they have elsewhere in similar circumstances, but of this
there is no sign.

Again, if the process of boring these channels was due to the mere
slow attrition by the waters on either side, how comes it that we find
no kitchen middens at all on the shores of the three great channels,
especially in their northern portions, nor yet in the smaller and
subsidiary channels between the various islands. Surely all this is
overwhelming evidence against the notion of gradual eating back
of these channels by slow denuding forces, and the burden of proof of
proving the contrary is very much indeed, thrust upon the advocates
of the opposite view. I would add, as another positive argument in
favour of the openings being the result of fracture, that in the case
of the Sound the two sides which approach each other within
4,480 yards at Elsinore differ vastly in geological structure. On
the Swedish side they are composed of Paleozoic rocks, and on that
of Zealand of chalk, thus showing that the Sound forms a great line
of fault where a rupture must sometime have occurred.

I must, therefore, take it for granted that the Baltic breach was
caused by a tectonic movement of the earth’s crust, and not by any
slow denuding action. This tectonic movement has left, as 1 now
believe, very notable evidences of its potency much beyond the
narrow waters which intersect the Danish archipelago, and extending
over a large part of the Chalk area of Southern Scandinavia and
North Germany and its islands, and had the effect of completely
shattering what were once continuous horizontal beds into their

358 Sir H. H. Howorth—Geological History of the Baltre.

present broken condition, and this, not in Tertiary times, but just at

the threshold of the current geological period.
' In order to set out the reasons for this important and really far-
reaching induction I must be allowed to make some preliminary
remarks on what may seem to be unnecessary to those who have not
measured, as I have done, the wis imertie of the older type of
geological mind which still survives among certain veterans of the
science.

There was a time when the various movements of the earth’s crust
(of which the evidence is patent enough) were attributed to the
operations of some unknown but postulated subterranean energy which
was supposed to be able (in limited areas) to lft up by forces acting
perpendicularly or to let down by similar impulses great masses of the
earth’s strata, and thus to largely cause the diversified features of
the earth’s crust. This view is now only held by a small and
shrinking body of geologists. The great mass of them who have
surveyed geological problems on a continental scale and realized how
far-reaching the phenomena must in some cases have been, have found
it impossible to maintain an hypothesis which will not meet the facts
as we now know them. The more influential of the modern teachers
of the science are no longer satisfied, like the extreme glacialists are,
to rely upon causes for which no adequate physical justification has
ever been preduced, and which necessitate the postulating of qualities
and characteristics in the materials which build up the earth’s solid
envelope which refuse to be verified by experiment. These newer
men who recognize that geology must in the long run rely upon
physics to supply it with a workable platform have found a perfectly
satisfactory reason for earth movements on a very big scale and over
very large areas. The postulate they stand upon in this matter is,
that the earth is inevitably Josing its heat by radiation and in the
process is shrinking, and in shrinking it has to compel its upper
strata to accommodate themselves to a smaller space. The result is
great lateral (and not perpendicular) thrusts which have squeezed
the beds into wave-like and sinuous curves and ribbons, with
alternating anticlinal and synclinal folds.

On this point let me quote two excellent authorities, and as there
must be no quarrel about their meaning I will quote their actual
words :—

Suess says definitely: ‘‘Es giebt keinerlei verticale Bewegungen
des Festen, mit Ausnahme jener, welche etwa mittelbar aus der Falten
bildung hervorgehen. Die Felsarten der Erde besitzen in keinerlei
Gestalt jene vithselhafte elevatorische kraft welche man ihnen in
einer Zeit Inzuschreiben geneigt, und vielleicht bis zu einem gewissen
Grade berschtigt war, im welcher. . . . Wir werden uns enschliessen
miissen letzte Form der Erhebungstheorie die Doctrin von den Saecu-
laren Schwankungen den Continent zu verlassen.’’ Heim urged the
same view (Jahrbuch k.k. Geol. Reichsanst Wien, 1880, p. 180).

Lapparent is still more positive. He says: ‘‘Il ne s’agit pas
d’avantage d’opposer a la doctrine des soulévements absolus
produits par des forces qui agiraient directement de bas en haut,
une protestation devenue sans objet. Car les partisans des impulsions

Sir H. H. Howorth—Geological History of the Baltic. 359

verticales sont, de nos jours plus, que clair semés et en dehors de
quelques rares attardes, personne n ’oserent encore attribuer a wae
telle action une part sérieux dans la formations des montagnes”
(Bull. Soc. Géol. France, ser. 11, t. xv, p. 217).

Again, the same graphic and lucid writer, speaking of what he
calls. ss impulsions verticales”’, says: ‘‘ Ils s’expliquent sans difficulté
si on les considére comme la production des movements généraux
d’une écorce soumise a des efforts latéraux de compression,
développées par la necessité ot elle se trouve de se plier aux
changements de dimension du noyau interne. De cette manicre
certaines parties se gonflent l’océan, tandis que d’autres semblent
Vattirer dans les sillons qui vont se creusant de plus en plus”’ ( Zraiteé
de Géologte).

It is assuredly by this process that the tectonic changes in the
earth which have diversified its surface into mountain and valley
have been in the main induced. It is equally plain that this process
of bending into undulations and curves cannot go on for ever with
such very tough materials as the earth’s crust is largely formed of,
without a break. The tension must presently be so great that the
rocks will give way and split, and form huge rifts and crevasses and
raw scarps and cliffs. Scandinavia presents us with most admirable
evidence of the results of this crumbling process on a large scale in
producing the diversified features of the country: a great many of us
are witness to that.. They meet us at every turn in the contortions
and folds made violently, and involving great breakages and gaping
wounds in the hardest crystalline rocks as well as in those of
Secondary age. ‘The Alps, the Pyrenees, and the Himalayas give us
similar very notable samples from Tertiary times, of raw angular
tears and rifts, gullies and nullahs, and perpendicular scarps and
faults, as well as huge anticlinal and synclinal bends and overthrows.
Mohn has picturesquely described the resultsin Norway. ‘‘ The oldest
formations in Norway,” he says, ‘“‘are greatly bent, compressed,
and distorted, and their parts forcibly dislocated, alike as regards
situation and relative height. Formations that in the interior he at
a height of several thousand feet are on the coast found level with
the surface of the sea; strata resting on the summits bordering
a lake or the shores of a fjord are again seen on islands in such lakes
or fjords and level with the surface of the latter. One side of
a valley exhibits a profile which, in regard to the height of the
various strata, differs materially from the profile of the opposite side.
The whole rocky shore is cut upin various directions, and the several
laming are now sunk beneath, now raised above, those adjoining
them. These dislocations have been caused by fissures, which in
many places can be pointed out, and the number of such recorded
faults of dislocation increases almost every year. ‘The direction of
the fissures is manifestly of the greatest assistance in indicating the
form exhibited by the surface of the country. The subsidence
between two fissures produces a valley or fjord; its rise, on the other
hand, a height or a promontory. Professor Kjerulf has succeeded in
showing that the entire system embracing the valleys and fjords of
Southern Norway may be easily referred to four principal directions

360 Sir H. H. Howorth—Geological History of the Baltic.

round about the principal directions of the valleys and fjords, and are
found grouped with predominant frequency.”

What Mohn says of Norway has been equally well said by De Geer
about the tectonic structure of Sweden. ‘‘ Up to this time ”’ (i.e. 1893),
he says, “‘I have levelled the marine limit at about seventy different
points on the southern and central parts of Sweden and in a few
places in Southern Norway. For Northern Sweden I have three or
four approximate but important determinations by Hogbom, Suevonius,

and Munthe. . . . All the observations relate to one system of
upheaval with the maximum uplift in the central part of the
Scandinavian peninsula along a line east of the watershed... .

Here the land must have been upheaved somewhat more than
1,000 feet (more than 300 metres), and around this cehtre the isobars
are grouped in concentric circles, showing a tolerably regular
decrease of height in every direction towards the peripheral parts
of the region, until the line for zero is reached, outside of which
no sign whatever of upheaval is to be found” (Bull. Amer. Geol.
Soc., 1892).

Elsewhere, De Geer, who has done so much for explaining the
internal structure of the great Swedish anticlinal, has carefully
co-ordinated the facts and drawn lines of isobars showing that they

omt to a focus of elevation along the medial line of the upliit,
curving down to lesser heights of similar altitude and synchronous in
date on the eastern and western sides of Sweden respectively (see D. G.,
Over Scandinaviens Nivafirandringar under Quartarperioden, p.56). He
tells us the first points he determined were in Scania, and the heights
of the different points were nearly equal on both sides of the axis;
some were 50 metres high, somewhat more towards the south; adding
that he afterwards obtained these successively at 48, 42, 37, 32, and
21 metres, and that in quite open localities.

Such being the structure of the great Swedish anticlinal, is it
strange or unexpected that it should in the south pass into a corre-
sponding and complementary synclinal hollow, with evidences, not of
rising, but of sinking? ‘hese are present (as I showed by much
evidence in the fourth part of this series of papers) all over the South
Baltic and extending to the North German coast. The line of
greatest depression, known as Forchhammer’s line, runs east and west
through the middle of the Southern Baltic. Would it not be strange
if the lifting up of this long whale-backed peninsula and this corre-
sponding synclinal movement in the south had taken place without
any breaks and breaches at the points of greatest stress, namely,
where the upheaval and the subsidence, caused by the lateral thrust,
were the greatest? It would indeed be strange if it were not so.
In the subsiding south, as we shall see, the material was chalk; in
the north, as we shall also see, the uplifted Primary rocks were the ones
to give way and be broken, and in both cases presenting the clearest
evidence of violent or momentary dislocations in places on a great
scale with tremendous breakages in the rocks. he great subsidence
in the Southern Baltic is partially attested by submerged forests and
peat bogs south of Scania. If the submergence had been gradual
and progressive along a disappearing beach, these fragile relics would

Sir H. H. Howorth—Geological History of the Baltic. 361

have been long ago. destroyed, and, like similar remains elsewhere,
they attest a sudden submergence.

I mention all this to establish a prima facie case. Let us now
turn to more direct evidence as displayed in the Danish islands and
on the South Baltie coast. The greater part of the Danish islands
are covered with drift beds in many places of enormous thickness.
These largely hide the subjacent chalk. It is not so covered every-
where, however. In the great Danish island of Zealand and in its
small satellite Moen the chalk is in part exposed, and in both we
have some yaluable evidence for our purpose. In the former the
part of the chalk that is visible is in a great measure undisturbed,
but not everywhere.

Rordam tells us the chalk of Zealand is for the most part covered
with diluvian beds sometimes 60 metres thick and enclosing large
masses of chalk. He describes a section thus: “ On voyait la Craie
recouverte d’argile morainique jaune-rouge, contenant aussi de
grandes portions de masses de Craie triturée et petrée d’argile
et de pierre. La figure 1, p. 8, fait voir incrusté dans l’argile
morainique un assez grand bloc de Craie de forme irreguliere”’
(n.ed., vi, 128).

Let us now turn to the small and geologically celebrated island
of Moen, separated by a narrow passage from Zealand, the land
on both sides of which channel consists of chalk. The tacts there
were long ago carefully collected on the spot and their inevitable
lesson pointed out by two excellent witnesses, namely, Lyell and
Forchhammer. Lyell, writing in 1878, speaks of the phenomena
presented by the island as being of a class which were thought
by the earlier geologists to belong exclusively to epochs anterior
to the existing fauna and flora, and quotes as examples faults
and violent local dislocations of the rocks and sharp bendings and
foldings of the strata, which we so often behold in mountain chains,
and sometimes in low countries, especially where the rock formations
are of ancient dates. He then proceeds to quote the island of
Moen as a striking illustration of such convulsions, to which he
assigns a post-Glacial or Pleistocene date. He describes it as about
60 miles in circumference and as consisting of white chalk several
hundred feet thick, overlaid by boulder-clay and sand made up of
several divisions, some stratified and some unstratified, the whole
having a mean thickness of 60 feet, but being sometimes twice that
thickness, and containing in one of its oldest members fossil marine
shells of existing species. He goes on to say, ‘Throughout the
greatest part of the island the strata of the drift are undisturbed and
horizontal, as are those of the adjacent chalk, but on the north-eastern
coast they have been through a certain area, bent, folded, and shifted,
together with the beds of the underlying Cretaceous formation.” ‘* Within
this area they have,” he says, ‘‘ been even more deranged than in the
English chalk-with-flints along the central axis of the Isle of Wight
in Hampshire, or at Purbeck in Dorsetshire. ‘he whole displacement
of the chalk is evidently posterior in date to the origin of the drift
since the beds of the latter are horizontal or inclined, curved, or
vertical where the ckalk displays signs of similar derangement.”

362 Sir H. H. Howorth—Geological History of the Baltic.

Again he continues, ‘‘ Although I had come to these conclusions
respecting the structure of Moen in 18386 after devoting several days
~ in company with Dr. Forchhammer to its examination, I should have
hesitated to quote the spot as exemplifying convulsions on so grand
a scale of such extremely moderate date, had not the island been
since thoroughly investigated by a most able and reliable authority,
the Danish geologist, Professor Puggaard, who has published a series
of detailed sections of the cliff.”” Commenting on one of the sections
showing great contortions, Lyell says, ‘‘ Where the cliff is 180 feet
high there is a sharp flexion shared equally by the chalk and the
incumbent drift. In each we observed a great fracture in the rocks,
with synclinal and anticlinal folds exhibiting in cliffs 300 feet high,
drift beds participating in all the bendings of the chalk.”

Near the northern end of Moen’s Klint, ata place called Taler, more
than 3800 feet high, are seen similar folds so sharp that there is an
appearance of four distinct alternations of the Glacial and Cretaceous
formations in vertical or highly inclined beds, the chalk at one part
bending over so that the position of all the beds is reversed. But the
most wonderful shiftings and faultines of the beds are observable in
the Dronningestol, part of the same cliff, 400 feet in vertical height,
where the drift is thoroughly entangled, and raised up with the
dislocated chalk. Lyell comments on these facts and says, ‘‘It is
impossible to behold such effects of reiterated local movements, all
of post-Tertiary date, without reflecting that but for the accidental
presence of the stratified drift, all of which might easily (when there
has been so much denudation) have been missing, even if it had ever
existed, we might have referred the verticality and flexures and faults
of the rocks to an ancient period, such as the era between the Chalk
with flints and the Maestricht Chalk, or to the time of the latter
formation or to the Eocene or Miocene or older Pliocene eras”’ (Lyell,
Antiquity of Man, 4th ed., pp. 888-98). Not the least wonderful of
these dislocations 1s the height to which the chalk was thrown up in
some of the cliff sections. Those who are familiar with the similar
phenomena in Norfolk, which I have known well and commented on
for many years, will see how in every detail they repeat those of Moen
as here described by Lyell and which I have no doubt were caused in
precisely the same way and at the same time.

It seems very probable, says Reclus, that having subsided Moen
was again raised above the waters. It is really composed of seven
distinct islets whose intervening channels have since been filled up.
In 1100 a.p. it still formed a group of three, and Borre (now lost
among the fens) stood on the beach in 1510, when a Lubeck fleet
anchored in front of the houses and burnt the place to the ground.

Moen is a natural step to the island of Rugen and the southern
coast of the Baltic. Here we meet with precisely the same kind of
chalk beds covered with drift, and torn and dislocated in the same
way and clearly at the same time. Reclus, in describing them, speaks
of ‘‘ the rocky shores of Moen and the lofty headlands of Rugen for-
merly united but now separated by a strait 33 miles broad and
12 fathoms deep”. Rugen, again, has its counterpart in the Baltic
coastlands near Stettin.

Sir H. H. Howorth—Geological History of the Baltic. 363

‘Neumayr (in his Hrdgeschichte, 11, 586-7), describing the Chalk
beds at Rugen and Stettin, speaks of the way in which diluvial soft
beds occur in masses detached from their matrix and transported
elsewhere; and of their being occluded in beds of the same age but of
different composition, with their internal laminee undisturbed, just as
we find them in Kastern England. In other places the strata are
largely crushed and squeezed and tossed about or faulted. ‘‘ Especially
notable,’”’ he says, ‘‘is the phenomenon which occurs in the case of
the deposits of white chalk on the shores of the Baltic as at Rugen
near Stettin and in other places of North Germany ; huge masses of
chalk have been here detached and planted in the midst of the boulder-
clay and have caused great disturbances in it. Thus Remele found
in the boulder formation at Stettin a huge slab (sehallen) of chalk
almost 2 kilometres long, that is more than a mile long, and of the
thickness of 25 metres, embedded in the drift beds. He also came
across similar instances elsewhere.’? Neumayr speaks of the great
cliffs of chalk facing the sea at Rugen and much broken. ‘These
breakages have only taken place in certain places ; while in others the
strata lie in their old horizontal position. Frequently there may be
seen great masses of chalk built up out of a congeries of confused chali
lumps, while in many places the chalk masses rest on diluvial sand
clay and boulder-clay, or these latter have forced themselves between
the boulders of chalk.

The latest authority on the Chalk of Northern Germany is
von Linstov of Berlin, whose paper entitled ‘‘ Die Techtonik der
Kreide in Untergrunde von Stettin, etc.’”’? contains.some valuable
materials for the elucidation of the problem, since they consist
largely of borings and testings of the different exposures. In none of
these borings has the chalk in situ been pierced; but in several
cases great masses of chalk proved to be true boulders lying in the
Drift like those of Norfolk. This was the case with the famous
great chalk boulder found at Frickenwalde in the middle of the last
century, and pronounced by Deecke in his Geology of Pomerania to be
2 kilometres long and 34:41 metres thick. It was found to be
underlaid by boulder clay, and what he calls glacio-fluviatile beds.
So with the great mass of chalk found at Katharinenhof, which was
of great size, thickness, and weight. A similar pair of great masses
was described by C. Muller, one from Sparrenfelde, west of Stettin,
and the other from the exercise ground at Kreckof. ‘These were
found when bored in 1898 to give the same result, namely, they
proved to be portentous boulders.

Linstov (op. cit., 144) also gives profiles of numerous faults
occurring in the chalk of the same district. He discusses the date
when the great breakage occurred, and rejects as impossible the
notion that they were pre-Glacial, and like Credner, in Rugen, he
puts them between the so-called first glaciation and the second one,
that is, makes them post-Pliocene.

The following table gives the details of other great masses of rock
occurring as boulders in the drift of chalk and Tertiery strata from
North Germany, which have been similarly tested :—

Bok” Sie TE oworth—Geological History of the Baltic

GeroLtocicaL Bortnes 1n Srerrin Disrrict.

Metres.
Finkenwalde. Boulder of so-called chalk. over 35 long
Gollnof, north-east of Stettin. Septaria clay. about 100
Ziillehof. Boulder of Septaria clay. 2-36:5
Gartz. Boulder of Septaria clay. 10-41
Stralsund. Boulder of chalk. 100
Gollenberg, near Késlin. Miocene and Oligocene. about 100
East Diervinof. Senonian chalk. 10-27
Treptov on the Rega. _ Boulder of Senonian Chalk. 31
Fort Chernoy, near Sonnen- Miocene. 65-8
berg (Neumark). :
Steinitten in Samland. Under Oligocene, Miocene, and 7-20
Senonian.
Osterode in East Prussia. Miocene, Oligocene, and 34
Senonian.
Frankfort on the Oder. Miocene. 4-80

According to Credner the drift beds overlying the broken and
dislocated chalk of Rugen are divisible into two sets. One of them,
the lower one, conformable with the chalk and which consists of two
greyish-blue boulder-clays, separated by bedded sands, and which
follow the fortunes of the chalk, and the other of certain boulder
clays, gravels, and sands which overlie the chalk unconformably and .
disregard its contortions. It is possible that the latter may be part
of a secondary movement, which has since the great submergence in
the Southern Baltic reversed the process to a small extent and left
its traces in different places by certain later breaches at low levels.

I now propose to say a few words about the exact parallel we have
in Britain to these Danish and German Chalk dislocations in the
disrupted chalk of Norfolk and elsewhere in England. ‘The pheno-
mena are precisely the same in detail and belong; so far as we can
judge, exactly to the same period, and were due to the same cause.
In England they have been made the pet toys of the Ultra-glacialists,
éspecially of those of them who were entrusted with surveying
the surface beds of Eastern England, and who quite ignored these
northern parallels which have been so carefully examined and
exploited by German geologists with great ardour of recent years.
I may, perhaps, be permitted to recall some of the arguments
I adduced long ago against the notion that the dislocations in the
chalk of Norfolk and the disposition of their broken debris were the
handiwork of a hypothetical ice-sheet or of ice inany form, and were
really the results of tectonic rupture of the chalk. The proposed and
quite imaginary ice-sheet, the mode of production of which is
admittedly an unsolved riddle, is supposed to have crossed the North
Sea from Norway when that country must have been at a much
lower level, as I propose to show later, to have crossed the vast
submerged valley (then much deeper) which bounds Norway on the
west, and to have travelled hundreds of miles without any adequate
thrusting force from behind it: when therefore, if it moved at all,
it must have been by a necessarily very slow progression of its layers
over each other in the fashion of a plastic body with very little
plasticity, and with a vertically extinguished motion at its base.
In order to secure this, it must have been piled up to a portentous

Sir H. H. Howorth—Geological History of the Baltic. 365

height; all this is jauntily suggested, forgetful of the fact that
the modulus of ice is such that it crushes and liquefies when sub-
jected to a very moderate pressure. This fantastic machine is
then supposed to have climbed up into Norfolk, and when only
moving at the speed of an exhausted tortoise to have done two
kinds of dynamical work quite inconsistent with each other, and at
the same time, namely, passed over numerous beds of stratified crag
sands without disturbing their layers, and at the same time to have
completely broken up the solid chalk, causing the greatest confusion
in its beds, which are crossed by endless faults, some of them scores
of feet in extent. It then proceeded to detach huge cakes of solid
chalk hundreds of yards long from the matrix (by what mechanical
process has never been explained), and in the process to have shattered
the great mass of the upper layers into myriads of unweathered
angular lumps and boulders and thousands of tons of chalk dust, and
to have bodily lifted up and carried in its terrific and destructive
arms, not only the great cakes and ribbons of chalk just named, but
also huge masses as big as houses, and whirled them along, and then
deposited them in the midst of stratified and beautifully laminated
sands without causing any breaks either in the lines or the curves of
the layers, which it arranged in concentric form about the intruded
masses, while in other places it laid down these sands in huge curves
with re-entering curvatures without any breaks in the lines, and in
other places to have torn up masses of these sands with their internal
structure undisturbed, and then carried off these fragile lumps
unbroken and uninjured at the time when it was pounding and
smashing and tearing the chalk to the depth of scores of yards.
All this°and much more I have set out years ago in papers in the
GerotocicaL Maeazrne, notably in a discussion of the ‘‘ Dislocations
in the Chalk of Norfolk” in the volume for 1907.

Since, then, it has become plainer every day that these dislocations
were not confined to Norfolk and Suffolk but were synchronous with
great movements of the chalk south of the Thames entzrely out of reach
of any ice-sheets; in the border of the English Channel, in Hampshire,
the Isle of Wight, in Northern France, in Flanders, and elsewhere.
The evidence seems to point to the same impetus haying been the real
cause of a great deal of the shaping of the north and south Downs
and of the synclinals which are correlated with these whale-backed
ridges, which in places have pot-holes on their surface containing
casts of Miocene shells, showing how late the upheaval must have
been. The same movement doubtless threw down the’ chalk in
Holland to a portentous depth, carrying with it in places hundreds
of feet of rearranged Crag and Pleistocene sands. It is clear that
the same portentous cause must also have operated in the Baltic
lands, inducing there a repetition of precisely the phenomena we
have in Norfolk, and, so far as the evidence leads, quite con-
temporaneously. All this capacity and work has been attributed
by a long dominant school especially potent in the arcana of Official
geology to the handiwork of ice, whose proved impotence to compass
such work they have entirely ignored, and who have refused to listen
to those who had been trained in the more precise methods of

366 Sir H. H. Howorth—Geological History of the Baltic.

physics, and warned them over and over again of the blind alley they
were following. They were faithfully copied for a long time by the
- geologists of Germany, who dealt similarly with their domestic problem
of explaining the shattered chalk of theirown country. Among them,
the most notable champions of ice were Wahnschaffe and Scholz,
and more lately Philippi. The first notable geologist in Germany
to make an effective revolt against the once current explanation of
these Cretaceous masses and their movements was Von Koenen, who
attributed the gigantic dislocations and movements involved to
tectonic earth movements on a great scale. He was presently
supported by Berendt, Hermann Credner, Cohen, Deecke, R. Credner,
and lastly by O. Jaekel and K. Keilhack. They were also at one
in regard to the date of the dislocations and the accompanying
phenomena, which they attributed to post-Tertiary times.

These German explorers, especially the later ones, have sifted the
evidence with skill and pains, and have tested some of the initial
difficulties with the boring rod. They are agreed that the phenomena
are not explainable by the action of ice, a view in which my friends
Professor Bonney and the Rev. E. Hill completely concur. After
paying two visits to Rugen they affirm that no evidence can be found
there to support the ice “theory. “‘ We shall be ready,” they say, ‘‘ to
admit the potency of ice-sheets as excavators, and benders or breakers
of rock masses when any evidence worthy of the name can be pro-
duced in proof that they operate in these ways; but though we have
diligently sought for it in the field we can only find it asserted on
paper” (Quart. Journ. Geol. Soc., lvii, pp. 16,17). This is precisely
the conclusion I have maintained in regard to the English beds for
many years.

Lyell and Credner both agree that the drift beds which lie
conformably to the Chalk in the Baltic lands and follow its
convolutions and lines of fracture were deposited before the great
disturbance took place, and Lyell distinctly describes it as post-
Glacial, that is, as I prefer to say, posterior to the deposition
of the drift, and it is a notable fact that that great master,
who saw a good deal further than some of his professed disciples,
should have so emphatically adhered to the view which seems the
only view consistent with the doctrine of uniformity that periods of
great disturbance in the earth’s crust were not confined to older
geological periods, but have occurred as late as Pleistocene times.
Those who were reproved by Lyeli so forcibly seem to forget that it
is in the very earliest geological periods that we have the fewest
evidences of contemporary dislocations on a great scale, and also the
largest extent of still undisturbed sina, while all the greatest
dislocations known to us took place in later periods, notably in
Tertiary times, as the Alps, which have been lifted up 21,000 feet
since Eocene days, and the western Himalayas quite as high since
Pliocene times, bear witness.. Is there any reason under heaven why
the process should have stopped in Tertiary times? How can anyone
who believes in rational uniformity maintain such a theory ?

Have not (as the Scandinavian geologists I have quoted have
shown) the two gigantic peninsulas of Greenland and Scandinavia

R. H. Rastall—The Genesis of Tungsten Ores. 367

been bodily uplifted from far below sea-level to a height of many
hundreds of feet in post-Tertiary times, as attested by the shell
peaches that girdle their flanks, and when the present living
mollusca were tenanting the present seas that wash their shores? Is
it a rational induction or the reverse to argue that if such enormous
movements in such tough rocks were the result of lateral thrusts
caused by shrinkage of the earth’s crust, which both induction and
experiment combine to establish, that thrusts on this scale could
hardly occur without the most serious breakages and fractures?

I have very little doubt, therefore, that the chalk dislocations of
the Baltic were consequential on the uplift of the great hog-backed
Scandinavian peninsula, and were almost certainly synchr onous with
the opening of the Baltic breach, which certainly dates from the
human period.

(To be continued.)

V.—Tue Genesis or Tunesten OREs.
By R. H. Rastauyu, M.A., £.G.S.
(Concluded from the July Number, p. 296.)
Parr IV: Srconpary Tunesten Deposits.

T the present time a large proportion of the world’s supply of
tungsten ores comes from secondary (detrital) deposits of various
kinds, formed by the normal denudation and redeposition of primary
ores exposed at the surface to the agents of weathering and
transport. It is impossible to form any idea of what fraction
of the world’s output actually comes from these sources, since the
published-statistics do not draw any distinctions in this respect, but
the amount is undoubtedly large. Although of such great economic
valne, the secondary deposits do not show any features of special
interest, and a lengthy description is unnecessary.

From this point of view the outstanding feature of the tungsten
minerals is their great stability and resistance to any kind of
chemical or mechanical alteration. Hence, like cassiterite and gold,
they are particularly prone to occur in both residual and alluvial
deposits. In many of the published descriptions, and especially in
the technical journals, a good deal of confusion is found to exist
between the residual deposits, where the material is still more or
less in place, and the true alluvial or transported deposits. From
their very stable character it follows that tungsten minerals must
tend to remain unaltered in the gossan of lodes and other masses and
also to concentrate in the shoad. Hence a kind of secondary enrich-
ment is found on the weathered outcrops of lodes. This is, of
course, not really an enrichment in tungsten ores, but rather
a removal of other constituents of a less stable nature, leading to
a concentration of the more resistant minerals of the weathered mass.
From their stability and high density it also follows that the
tungsten minerals are specially liable to occur as placers and other
forms of transported deposits. The same properties also lead to
a natural concentration in such deposits, especially in the lowermost
layers, resting on the bed-rock, and in natural rifles. In this

368 &. H. Rastall—The Genesis of Tungsten Ores.

respect both wolfram and scheelite behave like stream-tin, gold, and
platinum. In fact, the properties of wolfram are so like those of
eassiterite that their separation by mechanical processes is very
difficult, and it was not till the introduction of magnetic separation
that this difficulty was overcome.

Geologically the secondary tungsten deposits are so simple and
straightforward that it seems unnecessary to describe any individual
examples, while*the practical details of their exploitation, con-
centration, and after-treatment do not fall within the scope of this
paper. Essentially they consist mainly of breccias, gravels, and
sands, formed to a large extent by water-action, and occasionally
resulting from the effect of dry denudation in regions of small
rainfall. The briefest possible reference may also be made to the
““Head”’ of Bodmin Moor and other parts of Cornwall, so admirably
described by Mr. Barrow.’ In this connexion it may also be
mentioned that of late years it has been found profitable in many
instances to work over the old tin-dumps for wolfram, which was
thrown away as worthless by the earlier miners.

Part V: Conciusions.

In the foregoing pages an attempt has been made to give a general
account of the mode of occurrence and mineral paragenesis of the
tungsten ores. Attention has been paid chiefly to the theoretical
side of the subject, with a view to elucidating as far as is possible
the genesis of the ores and their relation to the associated minerals
and rocks.

Taking first the wolframite deposits, it is found that these occur
most commonly along with cassiterite; other minerals also accom-
panying them in nearly all cases are arsenopyrite and molybdenite.
The gangue minerals nearly always include some that are char-
acteristic of the pegmatitic or pneumatolytic dykes or veins.
Furthermore, it appears that this general association of tungsten,
tin, molybdenum, and arsenic may be further subdivided on the basis
of the rarer metallic elements present into subtypes or local metallo-
genetic provinces, such as the uranium province of Cornwall, the
tantalum-mobinm provinces of Burma and Dakota, and so forth.
Another major subdivision is afforded by the tungsten-tin-silver-
germanium group of Bolivia. From the evidence brought forward it
may be regarded as established that the tungsten-tin deposits are
derived in all cases from granitic magmas. Wolfram and cassiterite
are found as original minerals in granite, being direct products of
the crystallization of the magma; as constituents of pegmatite dykes
within and in direct continuity with the granite, while wolfram is
also found in quartz veins, so-called, which are continuations in
space of pegmatite dykes. Hence there is no real distinction
between a pegmatite dyke and a quartz vein, and the study of these
lodes lends strong support to the idea that many of the larger quartz
veins are in fact formed by crystallization of the last residues of
an acid magma. The separation of these residues is, of course,

1 Quart. Journ. Geol. Soc., vol. lxiv, p. 384, 1908.

kh. H. Rastall—The Genesis of Tungsten Ores. 369

essentially a process of differentiation, which may be described as
fractional crystallization. Processes of this kind are generally
described as pneumatolytic, but there does not seem to be any need
for the use of the word in this connexion, since as commonly under-
stood it seems to imply something unusual and out of the common
order of events. This kind of differentiation is perfectly normal; its
final results depend mainly on the extent to which highly volatile
compounds and water were present in the original magma. The
more of these are present the lower will be the freezing-point of
the final product. The effect of alkaline tungstates in lowering the
freezing-point of acid silicate melts, and thus enabling quartz and
acid felspars to crystallize, has long been known and used in petro-
logical and mineralogical research. It appears that during the
freezing of the residual magma cassiterite is formed first, then comes
wolframite, while last of all quartz and fluorite are formed, resulting
‘in veins of quartz and fluorite without metallic minerals, or even of
fluorite alone.

The evidence afforded by the wolframite lodes without tinstone is
entirely in conformity with the foregoing considerations. There is
a continuous gradation between the two types by diminution of
tinstone; the series passes through the wolfram-quartz lodes, in
which molybdenum and arsenic tend to disappear, whereas other
sulphides tend to increase. As the final member of the series we
have the association of wolfram with siliceous gold ores, as in
Colorado, and of scheelite with gold ores in California. This
relationship of tungsten to siliceous gold ores is of much interest in
connexion with the classification of ore-deposits proposed by Spurr.’
This author regards all ore-deposits as due to differentiation of
igneous magmas, the variations depending on the amount of water
and rarer elements originally present in the magma. According to
this scheme, the bulk of the tungsten deposits belong to the first or
pegmatitic type, which is characterized by tin, tungsten, molybdenum,
with tourmaline and topaz as gangueminerals. Some of the tungsten
ores, however, both wolfram and scheelite, extend into the second
group, ‘‘ the free-gold pyrite zone with quartz.”

Spurr correlates these differences mainly with depth, since he
regards all ores as deposited by ascending solutions. Although this
idea is highly probable, it cannot yet be regarded as demonstrated
that the tin-tungsten lodes were formed at a greater depth from the
surface than the gold lodes or the cupriferous pyrite deposits. This
point, however, is not of very great importance. It is a fact,
however, that the occurrence of tungsten ores when studied in
detail lends strong support to the idea of a definite sequence of
differentiation of the rarer metallic contents of the granitic magmas.

The tungsten ores are definitely oxidic in character, and in many
ways afford a strong contrast to the behaviour of the sulphidic ores.
They appear to belong characteristically to acid magmas, whereas
most of the great masses of sulphides are connected with basic
intrusions. There is also a strong contrast between the two classes

1 Spurr, Heonomic Geology, vol. ii, p. 781, 1907.
DECADE VI.—VOL. V.—NO. VIII. 24

370 =6R. A. Rastall—The Genesis of Tungsten Ores.

in the elements which act as ‘‘carriers”’. In the case of the
tungsten ores the most important of these is undoubtedly fluorine;
_boron is a very common associate, but it is not known whether it
plays any actual part in the formation of wolframite or scheelite.
A detailed study of the literature does not lend any support to the
statement sometimes found in textbooks that apatite is a common
associate of this group. In fact, minerals containing phosphorus or
chlorine seem to be conspicuously absent.

Another point of interest is that the tungsten minerals are all
characterized by a high degree of stability and consequent resistance
to chemical action of any sort. Hence they do not undergo any
alteration in the zone of oxidation and are not carried down in
solution into the zone of cementation. This is equivalent to saying
that they do not undergo secondary enrichment. It follows from
this that tungsten lodes are always primary in the narrowest sense
of the term, and this is a fact which should be taken into considera-
tion in the valuation of such deposits. The behaviour of tungsten
lodes in this respect is on the whole very similar to that of the tin
lodes, and shows no resemblance to the characters of the copper lodes,
for example.

To sum up, it may be said that the tungsten ore-deposits are of
magmatic origin, being formed by the natural and normal con-
centration in certain fractions of the magma of a group of
constituents, metallic and otherwise, which tend to occur together
owing to the similarity of their chemical and physical properties
under the conditions that prevail during the later stages of magmatic
consolidation. Of these constituents the most important are tungsten,
tin, molybdenum, arsenic, fluorine, and boron. These constitute the
general paragenesis, while certain regional subtypes can be dis-
tinguished, characterized by uranium, mobium, tantalum, and possibly
others not yet specifically distinguished. In certain cases transitions
can be traced to other groups of ore-deposits containing gold, silver,
copper, zinc, and lead. Some of these mixed deposits may be
explainable by deposition of metals in the same locality at two or
more distinct periods, while in other instances the differentiation of
the original magma may have been incomplete and ill-defined. At
any rate, it is clear that in the typical cases the prime factor at
work has been differentiation of igneous magmas, and the study of the
genesis of the tungsten ores lends the strongest support to modern
views as to the origin of ore-deposits in general. It is now
becoming increasingly manifest that the study of the characters and
origin of the metalliferous rocks is an extraordinarily interesting
and important branch of the science of petrology, and that in the
past this branch has been unduly neglected by workers on the purely
scientific and theoretical side. A detailed investigation of the
chemical and physical laws governing the formation of the oxides
and sulphides of the igneous rocks, on the same lines as already
applied by many workers to the silicates, could not fail to yield
results of the highest scientific interest and of the utmost practical
value.

Reviews—Geology of the Barberton District. 371

REVIEW Ss.-

I.—Tur Grotocy or tHE BaxBerton Gorp-minine Disrricr. By
A. L. Hatt. Memoir No. 9 of the Geological Survey of the
Union of South Africa. pp. 347, with 58 plates, 40 text-figures,
and a coloured map. Pretoria, 1918. Price 7s. 6d.

ie this comprehensive memoir Mr. Hall gives a detailed account of
the physiography and geology of the important Barberton gold-

mining district in the Eastern Transvaal and Swaziland. The

physical characters of the region present many features of interest:
in the west comes the great Drakensberg escarpment, here consisting
mainly of strata of the Potchefstroom or Transvaal system. The

‘“‘ Barberton Mountain Land’’, consisting of a large number of

mountain ranges, is composed chiefly of the slate-quartzite group of

the Moodies Series, while in the south is a great granite plateau.

The area shows a typical development of the Swaziland system,
which is subdivided into three groups, the Onverwacht Volcanic
Series, the Moodies Series, and the Jamestown Series: each of these
is penetrated by the older granite, while the Transvaal system rests
on all of them with a major unconformity. It is shown con-
clusively in this memoir that the granite is of later date than the
Swaziland rocks, and the chief interest of this point les in the fact
that the gold reefs are mainly to be found in the metamorphic
aureole of this granite. The Karroo System covers only a small
area, including the Komatipoort coal-field. The Moodies Series
consists of sedimentary rocks, chiefly slates and quartzites, whilst
the Jamestown Series now takes the form of chloritic and talcose
schists and other types probably derived from basic igneous rocks,
rather like the Keweenawan of North America. The later basic
intrusions are of little or no economic importance.

Besides the gold-tields of the De Kaap area and Northern Swazi-
land, the district also possesses economic possibilities in the form of
extensive deposits of magnesite and talc, while cassiterite has also
been worked on a small scale in one or two localities.

R. He R:

I1.—Reporr or rHeE Mines Brancw oF THE DEPARTMENT oF Mines,
CANADA, FOR THE YEAR 1916. pp. 183, with 14 plates and
10 figures. Ottawa, 1917. Price 25 cents.

HIS report contains a general summary of the work of the
Department for the year, together with individual reports on
various subjects that have been specially investigated. Among
these are notes on occurrences of iron-ores and building and orna-
mental stones, and on a reconnaissance for phosphate in the Rocky

Mountains and for graphite in British Columbia. In Canada, as in

England and in the United States, much attention is now being paid

to sands suitable for metallurgical purposes, and a large amount of

work has been carried out by the Department on this subject.

Attention was also paid to the possibility of removing lime from

impure magnesite, such as is found in the Grenville district; this is

372 Reviews—Geology of the Bawdwin Mines, Burma.

contaminated with dolomite, and when the mixed rock is heated to
about 1,000° C. in an electric furnace the magnesite becomes darker
-in colour. On slaking the magnesite material forms a very coarse
gritty powder, while the dolomite lime forms a milky paste which
can be easily removed by washing; hence a separation can be readily
effected. The fuel-testing and ore-dressing sections of the Depart-
ment have also conducted much useful work in various special
directions, and the whole report gives evidence of much energy and
activity.
Dipdals he

IIlI.—Gronocy AnD Ore-pDEpPosITs oF THE Bawpwin Mines, Burma.
By J. Coaatn Brown. Rec. Geol. Sury. India, vol. xlvii, pt. ii,
pp. 121-80, with 8 plates, 1917.

f{\HE Bawdwin ore-deposits are enclosed in a series of rhyolites and

rhyolitic tuffs, which form a kind of dome protruding through
the younger Pangyung (Cambrian or Ordovician) strata. Above
these is a regular sequence to the Devonian, and then an uncon-
formable series of Jurassic sandstones, clays, and limestones. At one
horizon in the Silurian many specimens of Monograptus have been
found. The rocks of the volcanic series are much weathered, and
their original character is not always easy to determine, but all the
ore-bodies seem to lie in the tuffs rather than in the rhyolites. The
ore-bodies all lie in a well-marked zone or channel about 8,000 feet
long and 400 or 500 feet wide, possibly connected with an ancient
fault system.

There are three distinct lodes of lead-silver-zine ore, but of much
more importance is the Chinaman ore-body, which is an enormous
replacement deposit of zinc-lead-silver ore, lying on the hanging-
wall side of the ore-channel. The essential constituents of the
ores are galena and zine-blende with a little pyrite and chalco-
pyrite. The ore is always argentiferous, showing on the average
about 190z. to the ton. The gangue consists of metamorphosed
country rock and a little quartz. The zine ore appears to be as
a rule of earlier formation than the galena, while the copper and
iron sulphides are intermediate. Carbonates, sulphates, and other
oxidized ores of lead and zinc have long been worked by the Chinese,
but are now nearly exhausted.

The author considers that the origin of the ores is to be attributed
to the intrusion of granite masses into the ancient volcanic rocks,
hot solutions having risen along shattered fault-planes previously
produced and replacing rocks readily susceptible of mineralization,
such as these rhyolitic tuffs would appear to be. The reserves of
sulphide ores are very large, and after many vicissitudes the mines
appear to be now in a flourishing condition, largely owing to the
construction of a narrow-gauge railway 50 miles long, and bid fair
to become one of the great zinc-lead producers of the world.

Reviews—Corundum in South Africa. 373

1V.—Rerort on cprrain Minprals USED IN THE ARTS AND
Inpusraizs. V. Corunpum. By P. A. Waener. South
African Journal of Industries, vol. i, No. 9, pp. 776-97.
Pretoria, 1918.
WING to the stoppage of the supplies of crude emery from
Turkey and Greece the demand for the purer forms of corundum
has greatly increased, especially as the better qualities are much
more satisfactory in use, and are now very largely employed in
munition-making. None of the artificial substitutes are found in
practice to give such good results for the finer kinds of work and for
specially hard materials. The output of South African corundum
for the year 1917 amounted to 2,628 tons, so that the Union is now
the largest producer of any country in the world. At the present
time the corundum is mainly derived from surface deposits of one
kind or another: gravels, more or less cemented conglomerates and
boulders of disintegration : its original home is, however, undoubtedly
in the gneisses and schists of the Swaziland series, where it is
associated with a typical assemblage of metamorphic minerals, while
the rocks are traversed by pegmatite dykes and veins: corundum
is sometimes found in these also. The crystals are often very large,
up to 10 inches in length by 5 inches in diameter. They are
remarkably free from inclusions, and hence very pure samples can be
obtained.

The chief corundum fields at present known are in the Zoutpansberg
and Leydsdorp districts in the Northern Transvaal; some considerable
deposits are also known in Little Namaqualand, while less important
occurrences arenumerous. This industry appears to have a promising
future.

Rij H.R:

V.—Furmr Iuprtemenrs 1n SUFFOLK.

On some Human anp Animat Bones, Frurnt ImpLemeEnts, ETC.,
DISCOVERED IN TWO ANCIENT OccUPATION-LEVELS IN A SMALL VALLEY
near Ipswich. By J. Rerp Morr. Journ. Roy. Anthrop. Inst.,
vol. xlvii, pp. 867-412, pls. xv, xvi, 1917.

Tue Ancimyt Friyvr Imerements or Surrorx. By J. Rem Morr.
Proc. Suffolk Inst. Archeol. and Nat. Hist., vol. xvi, pp. 1-88,
UOT.

OR two years Mr. Reid Moir had under close observation two

well-marked occupation-levels in the deposits covering the sides

of a small valley near Ipswich. A grant from the Percy Sladen

Memorial Fund provided him with the requisite labour to make

careful excavations. We now welcome his results, published in

detail with numerous beautiful illustrations of the flint implements
and other discoveries.

On the lower floor examined were found numerous bones of stag,
roe deer, ox, pig, goat, and horse, besides some doubtful traces of
mammoth and Irish deer. There were also three human bones,
indistinguishable from those of modern man. The associated flint
implements are of late Mousterian type, and there are also fragments

374 Reviews—Geology of the Birmingham District.

of very rough and primitive pottery. ‘The flint implements from the
upper floor are all Aurignacian, and two specimens from a still later
deposit are clearly early Solutrean. The succession of the deposits
in the valley near Ipswich is therefore the same as that already
noted in the caves of France and Belgium.

Flint implements of all ages since the appearance of man have now
been recognized in Suffolk, and Mr. Reid Moir has also published an
interesting and useful summary of these, with excellent illustrations
of the principal types, and a bibliography. We commend his paper
to those who desire a clear elementary statement of the subject.

VI.—Gerotoey or tHE BrruincuHam Disrrict.

THE Downrontan or Sour Srarrorpsarre. By W. Wicksam
Kine and W. J. Lewis. Proc. Birmingham Nat. Hist. and Phil.
Soc., vol. xiv, pp. 90-9, 1917. .

On Buarrorp AND oTHER Insect REMAINS FROM THE SouTH STAFFORD-
SHIRE CoaLrieLp. By H. Boron. Ibid., pp. 100-6, pl. vii.
Mammatran Remains In tHE GuractaL GRAvELS AT SrovuRBRIDGE.

By W.S. Bourton. Ibid., pp. 107-12, pl. viii.

fF\HERE are three papers of special interest to geologists in the

latest part of the Proceedings of the Birmingham Natural History
and Philosophical Society. Messrs. King and Lewis have continued
their researches on the Downtonian of South Staffordshire since their
contribution to the Groroetcat Macazine in 1912 (Dec. V, Vol. IX,
pp. 437, 484), and they now publish a detailed summary of their
results. They have found numerous fish-remains which determine
the age of the deposits with certainty ; and as these rocks are on the
faulted fringe of a great coal-field, a knowledge of their precise
sequence is of economic as well as of scientific importance.
Mr. Herbert Bolton describes three wings of insects from the Coal-
measures, probably of Coseley, one representing a new species of
Phylloblatta, the others belonging to Brodia priscotineta. Professor
W. S. Boulton gives an account of a sand-pit at Amblecote,
Stourbridge, in which teeth of Hippopotamus have been found with
remains of Hlephas primigenius, Rhinoceros antiquitatis, and Bison
priscus. All the bones and teeth are very fragmentary, but they
show httle evidence of having been rolled or water-worn. Careful
search has been made for stone implements, but none have hitherto
been identified. The spot is evidently well worth continued
observation.

VII.—Tae Paytoceny anp Curassirication or Reprines. By
S. W. Witutsron. Contributions from Walker Museun, vol. i,
No. 3, 1917.

ROFESSOR WILLISTON states that in this paper for the first
time he ventures to express in tabular form his views as to the
phylogeny and classification of the Reptilia. As he remarks, he has
no startling novelties to offer, but nevertheless he makes a clear
statement of the results of recent work which will receive the assent

Reviews —G. A, Boulenger — Eocene Lizards. 375

of most paleontologists. The idea that in Hatteria we had the
most generalized type of reptilian skeleton found among recent
reptiles, and the belief that Paleohatteria was a member of the same
group, for a long time misled most writers as to the inter-
relationships of the Reptilia. Cope, however, had already pointed
out that the temporal region of the skull supplied the surest basis
for forming an opinion as to reptilian affinities, and this idea was to
a great extent carried out by A. 8. Woodward. Osborn & McGregor
made still more extensive use of these characters in drawing up
their well-known system of classification. Professor Williston
jikewise employs the same characters, but has arrived at somewhat
different conclusions from the two last-mentioned writers.

The main divisions he adopts are (1) Anapsida, (2) Synapsida,
(3) Parapsida, (4) Diapsida. ‘he first includes the Cotylosauria and
the Chelonia, the former having no temporal opening in the skull and
being probably directly derived from the same stock as the Stego-
cephalia. ‘The second includes the Theromorpha, Therapsida, Sauro-
pterygia, and Placodontia, in which there is a single temporal fossa
which he believes arose from a separation of the jugal and squamosal.
In the third, which includes the Ichthyopterygia, the Squamata,
Proganosauria, and Proterosauria, there is likewise only a single
temporal opening, which, however, is regarded as having been formed
independently of the openings found in other phyla, the streptostylic
type of skull found in the Squamata having arisen from the cutting
away by the lower edge of an originally broad squamosal bar such as
is found in the Permo-Carboniferous Areoscelis. Vhe fourth group,
the Diapsida, includes the remaining reptiles, in which there are two
temporal fosse (lateral and superior), of which the lower one is
regarded as the older, the upper having arisen as the result of a
secondary separation of an orbito-squamosal arch. The introduction
of the name Parapsida for a separate phylum including such, at
first sight, dissimilar types of reptiles as the Ichthyosauria and the
Squamata is the chief innovation in this paper, but the writer gives
good reasons for its introduction, as he does for his other conclusions.

VIIJ.—Eocrne Lizagps Iv France. By G. A. Bourenenr.

N a recent note published in the Comptes Rendus of the Academy
of Sciences, Paris (vol. 166, p. 889), Mr. Boulenger has shown
that some of the genera of lizards (e.g. Placosaurus, Gervais, and
Plestiodon, Filhol), from the Upper Eocene Phosphorites of France,
belong to the family Helodermatide, which at the present day is
represented only by the poisonous Gila Monster (Heloderma) of
Arizonaand Mexico and by Lanthanotus of Borneo. ‘The determination
of the relationships of these Phosphorite lizards was made possible
by the discovery of a skull showing the rudimentary condition of the
squamosal characteristic of the family. Mr. Boulenger is also able
to state definitely that the dermal scutes described by Filhol under
the name WVecrodasypus, in the belief that they belonged to an
Armadillo, are in fact cranial scutes of these Helodermatid lizards.

376 Reviews—C. Gaillard on Heterosorex.

IX.—Novveav GENRE DES MUSARAIGNES DANS LES DEPOTS MIOCENES
pe LA Geive Sarnt-Atpan (Ishre). By Cr. Garttarp. Ann.
Linn. Soc. Lyon, tom. lxii, p. 88.

1 this paper Professor Gaillard gives a very detailed description of

the skull and mandible of an interesting new Insectiyore
(Heterosorex delphinus) which, while evidently referable to the shrews,
shows some primitive characters, and in some respects approaches the
moles, e.g. in the possession of a complete zygomatic arch and in the
form of the fourth upper premolar. ‘The skull is notable for its
shortness and for the relatively great width of the cranial region.
The mandible, so far as its posterior region goes, seems to be very
similar in structure to that of Neomys fodiens, but is about one-third
larger. The dental formula is as in Crocidura. The new form is
said to be most nearly related to certain Asiatic genera of shrews,
and also to have some resemblances with Urotrichus, a mole from
East Asia. Probably it had undergone considerable modifications as
a burrowing animal, but unfortunately the limbs are at present
unknown. The last part of the paper consists of a careful comparison
of Heterosorex with the fossil shrews hitherto known.

X.—Paracortan GroLoey.
Tae Proprem of tHe Creraczous—Trertiary Bounpary 1n Sourn
AMERICA, AND THE STRATIGRAPHIC Position oF THE SAN JORGE
Formation 1n Paraconta. By A. Winpuausen. Amer. Journ.
Sci. [4], vol. xlv, pp. 1-58, 1918.
N California, Chile, and Patagonia it has been claimed that there
is a gradual transition from the Cretaceous to the Tertiary faunas,
with a remarkable mingling of types. Dr. Windhausen maintains
that this is not the case, but that there is good evidence of a marked
unconformity in all these regions. He describes and discusses the
Upper Cretaceous and Lower Tertiary formations which he has
examined in Patagonia, and concludes that they are distinctly
separated both by a stratigraphical and by a faunistic break. He
agrees with the brothers Ameghino that mammalian remains have
been found associated with bones of Dinosaurs; but he considers that
this association occurs in Paleocene, not in Cretaceous, deposits.
Both sauropodous and theropodous Dinosaurs are met with in the
Cretaceous of Patagonia, but only the latter range upwards into the
Tertiary.

XI.—On tHe CrrstattocrapHy anp Nomencnaturr oF HoLnanvire.
By L. L. Fermor. Rec. Geol. Surv. India, vol. xlviii, pt. iu,
pp. 103-20, 1917.

tC a former paper the author showed that hollandite is a crystalline
mineral having the same composition as psilomelane. Further

study of specimens from the original locality has shown that it

belongs to the pyramidal class of the tetragonal system. It is also
pointed out that the name romanéchite was applied by Professor

Lacroix in 1900 to a mineral from Romanéche in France, which

appears to be identical with or closely allied to hollandite.

Reports & Proceedings—Geological Society of London. 877

XII.—Inon-orr Occurrences 1n Canapa. Vol. II. By E. Linpeman
and L., L. Borron. Canada, Department of Mines. pp. 222 and
33 maps. Ottawa, 1917.

f{\HE first volume of this publication has already been noticed in

these pages; the second volume contains detailed descriptions
of all the known occurrences of iron-ores within the Dominion.
These include almost every known variety of ore, but the great
majority of them seem likely to be of small commercial importance,
at least under the present economic conditions.

XIII.—Sprecran Reports on vHe Minerat Resources oF Great
Brarrain. Vol. Il]: Gypsum anp ANnuHyYDRITE, CELESTINE AND
SrRONTIANITE. Second edition. By R. L. Surrrock and B.
SmirH. pp.iv+64. 1918. Price 2s.

HE second edition of this memoir is in the main a reprint of the
first edition, but some further particulars have been given of
deposits of gypsum in Nottinghamshire and Somerset, together with
estimates of the reserves of gypsum still available in different
districts.

Pe @ Pepe ss) Aan) gtk @ Cane) TING S=

I.—Geotoeicat Society or Lonpon.
1. May 15, 1918.—G. W. Lamplugh, F.R.S., President, in the Chair.

A lecture on ‘‘The Geology of the Italian Front’? was delivered
by Professor E. J. Garwood, M.A., Sc.D., F.R.S. The lecture was
illustrated by lantern-slides, geological maps and sections, and tables
of strata.

The President expressed to the Lecturer the thanks of the
Fellows present.

2. June 5, 1918.—G. W. Lamplugh, F.R.S., President, in the Chair.

(1) ‘“‘The Kelestomine, a Sub-Family of Cretaceous Cribrimorph
Polyzoa.” By William Dickson Lang, M.A., F.G.S.

The Kelestominz are a sub-family of Pelmatoporide. The latter
are a family of Cretaceous cribrimorph Polyzoa, whose cost are
prolonged upwards as hollow spines from the median area of fusion
of the intraterminal front-wall. The broken ends of these spines
form a row of pelmata (or, if small, pelmatidia) on the intraterminal
front-wall.

The Kelestomine are Pelmatoporide with an apertural bar each
half of which is bifid; and the proximal and distal forks of each half
are fused with the corresponding forks of the other half. The fused
distal forks are also fused with the proximal pair of apertural spines,
which are greatly enlarged.

The simplest known form of this arrangement is seen in the genus
Kelestoma, Marsson. elestoma is characterized among the Keles-
tominee by its great cecial length, and by the great number of costa.
Kelestoma has the following three species, which form a single

378 Reports & Proceedings—Geological Society of London.

lineage: (1) elestoma elongatum, Marsson, with an incrusting
asty ; (2) a new species, with a bilaminar, erect asty; (8) &. scalare,
Lang, with an erect, cylindrical asty. There is, in this series,
a slight catagenetic decrease in the number of cost, and the
avicularian aperture becomes somewhat more pointed. The genus
occurs in the Senonian, zone of Belemnitella mucronata, in the island
of Riigen. :

Morphasmopora, unlike Kelestoma, retains a small number of cost
and a short cecium; but the thickness of the proximal apertural
spines, which are hardly recognizable as such, is enormously
increased; the thickness of the bifid apertural bar is also increased.
In Jdforphasmopora brydonet, Lang, there are four circum-apertural
avicularia; and the proximal apertural spines and the apertural bar,
though enormously developed, are not so large as in Wf. gukes-browner
(Brydone). ‘The latter species has fewer coste than the former, and
but one pair of circum-apertural avicularia. There are also differences
in the intereecial and interstitial secondary tissue of the two species.
Mf. brydonet occurs in the island of Riigen and I. jukes-browner at
Trimingham; both from the Senonian, zone of Belemnitella mucronata.

(2) ‘The Geology and Genesis of the Trefriw Pyrites Deposit.”
By Robert Lionel Sherlock, D.Sc., A.R.C.Sc., F.G.S.

This pyrites deposit 1s worked at Cae Coch Mine, on the western
side of the Conway Valley (North Wales), about 1 mile north of
Trefriw. :

A band of pyrites, about 6 feet thick, and of considerable purity,
rests on the inclined top of a thick mass of diabase which is shown
to be intruded into the Bala Shales that cover the ore-body. The
shales immediately above the pyrites are shown by the graptolites
contained to belong to the zone of Nemagraptus gracilis, and are the
equivalents of the Mvdrim Limestone of South Wales and of part of
the Lower Cadnant Shales of the Conway Mt. succession: that is,
they are near the base of the Bala Series according to the Geological
Survey classification (Carmarthen Memoir, 1909). Northwards the
intrusive is bounded by an overthrust mass of volcanic ash, which
itself is cut off by an east-and-west fault against rhyolite, well seen
in a roadside quarry and in the crags of Clogwyn Mawr.
Intrusions of dolerite of much later age, probably late Devonian, or
Carboniferous, are found in the rhyolite, and form the plateau above
the mine, passing over shales, diabase, ash, and rhyolite in turn.

Pyrites deposits are classified by Beyschlag, Vogt, and Krusch in
four groups: (1) Magmatic segregations, (2) formed by contact-
metamorphism, (3) lodes, (4) of sedimentary origin. None of these
modes of origin, however, will account for the Trefriw pyrites.
The conclusion arrived at is that the diabase was intruded below a
bed of pisoliticiron-ore. Hot water containing sulphuretted hydrogen
given off from the intrusion, combined readily with the pisolites,
which were in the form either of oxide or of silicate of iron, and
formed pyrites. The graptolitic horizon at which the pisolitic ore
occurs usually contains some pyrites, and this would be added to
that derived from the above reaction. The pyrites was not formed
by ordinary contact-metamorphism; because the intrusion is seen,

Reports & Proceedings—Geological Society of London. 379

at places where the pyrites is absent, to exert only a slight hardening
effect on the shale. In North Wales pisolitic iron-ore is known to
occur in several places at the horizon of Vemagraptus gracilis. From
the mode of origin assigned above to the pyrites it follows that the
mineral is of Bala age, since it was formed before the intrusion,
itself of Bala age, had cooled. The pisolitic ironstone must have
been in existence in Bala times, and this supports the idea that the
ironstone is a bedded contemporaneous deposit.

3. June 19, 1918.—G. W. Lamplugh, F.R.S., President, in the
Chair.

A lecture on ‘‘Some Features of the Antarctic Ice-cap”’ was
delivered by Major Sir Douglas Mawson, D.Sc., F.G.S. In the
course of his lecture, which was illustrated by a large series of
lantern-slides, Sir Douglas Mawson said that the ice mantle of the
south formally involved sub-Antarctic Islands, Patagonia, Southern
New Zealand, and the higher mountains of Tasmania and of the
neighbouring portions of Australia, but it retreated to its present
confines—a circum-Polar Continent—at a time apparently concurrent
with the disappearance of the extensive Pleistocene ice-sheets of the
Northern Hemisphere.

The existence of a great land mass situated on the face of the ©
globe just where the sun’s rays fall most obliquely has the effect of
intensifying the Polar conditions. This result is achieved by reason
of the elimination of the ameliorating influence of the ocean and as
a result of the acceleration of the circulation of the moist atmosphere
from the surrounding sea to the land, owing to the wide difference in
temperature pertaining over the oneand the other. Thus the presence
of extensive land at the Pole, in contradistinction to ocean, results,
under present cosmical conditions, in increased refrigeration, and
consequently in greater extension of the Polar ice-cap. This in
turn reflects on the average temperature of other regions of the
globe, for an ice surface absorbs but a relatively small proportion of
the sun’s radiant heat. The existence of the Antarctic Continent
must therefore have some bearing on the climate of the Northern
Hemisphere and be reckoned with as a factor contributing to the
refrigeration thereof.

The lecturer laid great stress upon the work of the outflowing
surface winds in developing the domed form of the ice-cap. These
winds, owing to their persistence and violence, strip the surface of
much of the newly fallen snow, and otherwise ablate the marginal
zone, thereby considerably reducing the volume of ice that would
otherwise reach the sea by glacial flow. Crevasses in the ice-cap
observed far inland at ‘‘The Nodules” indicate that the ice of the
hinterland is in motion.

In the seaward termination of the ice-sheet at Cape Denison, a
basal zone, attaining as much as 50 feet in thickness, bearing
englacial drift, is a well-marked feature.

The shelf-ice formations, including the Ross Barrier and the
Shackleton Shelf were specially referred to: mention was made

380 Reports & Proceedings —Mineralogical Society.

of their growth and decline, of a method of determining their depth
below water, and of the probability of specialized life existing
beneath such formations.

The President expressed to Sir Douglas Mawson the thanks of
the Fellows and visitors for his lecture.

I].—MinrratogicaL Socrery.
June 18, 1918.—W. Barlow, F.R.S., President, in the Chair.

W. A. Richardson: ‘‘On the Origin of Septarian Nodules.’’
Septarian structure consists not of a simple combination of radial
and concentric circles, but of irregular polygons closely simulating
mud-cracking. By experiments with clay balls and films and
comparison with timber cracks it was shown that radial cracks
widening inwards are produced by internal circumferential contrac-
tion, radial cracks widening outwards by internal expansion, con-
centric cracks by contraction towards the centre, and polygonal
cracks by either free or chemical desiccation. Moreover, analysis
shows that septarian nodules are more aluminous towards the centre
than the outside, and are therefore capable of contraction. The
evidence disproved the expansion theories, and showed that con-
traction on numerous centres in a colloidal medium caused the
cracking, and desiccation by chemical agents the contraction. The
central portions are not merely enclosed clay, but clay that has
undergone considerable chemical modification, and the original
colloidal nature of the medium is so changed that closing of the
cracks by absorption when placed in water cannot take place.
Finally, the occurrence of the nodules suggests their origination by
rhythmic precipitation according to the laws of Liesegange from
solutions of bicarbonates diffusing through a colloidal medium.

Dr. G. T. Prior: ‘‘The Composition of the Nickeliferous Iron of
the Meteorites of Powder Mill Creek, Lodran, and Holbrook.’
A simple and expeditious method of determining the amount and
chemical composition of the nickeliferous iron of a meteorite was
described. The method depends upon the use of dimethyl glyoxime
for the separation of nickel. Its application to the meteorites
of Powder Mill Creek, Lodran, and Holbrook gave percentages
respectively of about 42, 30, and 63 of nickeliferous iron, in which
the corresponding ratios of iron to nickel were about 18, 114, and 5.

CORREHSPON DEHN CHE.

eames
MOUNTAIN BUILDING.

Str,—The aim of my article in the Grotocicat Magéazine for
May was to point out that those data for the earth’s thermal condition
and past history that agree best with evidence derived from totally
different sources lead directly to an amount of compression of the
earth’s crust in cooling that is of the correct order of magnitude to
account for mountain building. Mr. Deeley in his reply makes no
attempt to answer this statement. What he does is to suggest that

COorrespondence—C. N. Bromehead. 381

different data, less satisfactory on other grounds, might lead also to
a less satisfactory amount of contraction or even to an expansion.
This is an argument in favour of the data and of the theory, and not
against them.

His assertion that I would have readers ‘‘ believe that the thickness
of the radio-active layer has been fairly accurately measured”’, and
his charge of ‘‘dogmatism”’, are definitely untrue. It was because
itis not accurately known that I determined the available compression
on two hypothetical distributions of radio-active matter, both per-
missible on other grounds, but widely different; the results they
gave were not very different and were stated in the article.

I introduced no new theories regarding the properties of matter.
What I did was to classify in a convenient way the known behaviour
of different types of matter under shearing stress. The statement
quoted from Maxwell that liquids and perhaps most solids are
perfectly elastic as regards stress uniform in all directions is irrelevant
to my discussion, which was explicitly limited to the differences
between the stresses in different directions. In the light of present
knowledge the account of shearing stress in Maxwell’s book needs
revision; for it makes no reference to elastic after-working or to the
elasticity of such a substance as pitch, which in my classification
would be a plastic solid with a very low limiting stress-difference.
The common practice of regarding as a liquid a substance so elastic
that tuning forks can be made of it is exceedingly inconvenient.

Had the conclusion, that my views on the solid and liquid states are
quite inadmissible, been accompanied by the slightest argument, it
might have been more impressive; or it might not.

Hanrotp JEFFREYS.

THE PRE-THANETIAN EROSION OF THE CHALK.

Sir,—I have read with much interest the suggestive paper by
Mr. H. A. Baker on the ‘“‘ Pre-Thanetian Erosion of the Chalk in the
London Basin”. I have for some time past been accumulating
evidence for a similar study, but in 1915 wrote that ‘‘ the evidence
. .. is as yet too slight to allow of a definite map being made”
(Geology of Windsor and Chertsey, Mem. Geol. Surv., p. 14).

Mr. Baker’s map (Fig. 1) includes the area to which I referred, and
appears to be based upon less evidence than that which my work for
the Geological Survey had afforded. In the construction of such
a map it seems natural to ascertain as far as possible the zone of the
Chalk immediately underlying the Tertiary at the boundary of the
latter, and to check the zones whose presence beneath the Tertiary is
deduced from borings by these facts. This has not been done by
Mr. Baker. The zone of Chalk on which the Tertiary rests has been
ascertained by the Survey in the south-western part of the area
shown on Mr. Baker’s map, and a portion of the results has already
been published (op. cit.). From the neighbourhood of Beaconsfield to
the western margin of the map forming Fig. 1 he shows the base of
the Tertiary as resting on the zone of A. quadratus. The fact is,
that the zone is that of WU. cor-anguinum at Beaconsfield, Marsupites

382 Obituary— William Lower Carter.

and possibly quadratus at Taplow, cor-anguinum again south and
west of Taplow to the margin of the area, where Marsupites comes on
again. In this part of the area, at any rate, Mr. Baker’s zonal
boundaries, deduced from borings, are m marked discordance with
the facts ascertained and published.

I do not, however, wish to suggest that the method of deducing
the Sub-Tertiary zones from boring records is useless; on the
contrary, when the amount of evidence available is larger, the
method may be of some value. The results obtained by Mr. Baker
show that his evidence is insufficient, but that may be because he
has apparently not made use of all the evidence available. For the
benefit of those interested in the subject I may add a few points not
mentioned in the paper I am criticizing; all are referred to in the
memoir I have quoted, while the first was published in 1886. At
Egham the Chalk Rock has been proved at a depth from the surface
of 700 feet, or 346 feet from the top of the Chalk, suggesting the
presence of quadratus zone; at Ottershaw the total thickness of
Chalkis known to be 646 feet, suggesting Marsupites ; at Windsor the
Chalk is exposed below the Tertiary and probably belongs to the
lower part of cor-anguinum.

From this evidence, combined with that referred to by Mr. Baker,
I inferred that the plane on which the Tertiary rests ‘‘ has been cut
across a series of gentle folds whose axes run about EK. 15° 8.”
(op. cit., p. 14). Ido not regard the above as more than a tentative
solution of the problem, and it refers only to the southern half of the
area mapped by Mr. Baker (Fig. 1), but I wish to point ont that his
conclusions must at any rate be regarded as ‘‘ not proven”’.

T donot understand the suggestion on p. 299 that ‘‘ the Streatham—
Beckton fault is pre-Tertiary’’. It is certainly post-Tertiary, since
it involves the Tertiary strata and dislocates the upper surface of
the Chalk. Whether there was pre-Tertiary movement along the
same line we have as yet no means of ascertaining.

C. N. Bromeneap.

GEOLOGICAL SURVEY AND MUSEUM,

JERMYN STREET, LONDON, S.W. 1.
July 9, 1918.

(Qs SveseOpy NAS Se ge
WILLIAM LOWER CARTER, M.A.; F.G.S.
Born AvGust 9, 1855. DIED JUNE 19, 1918.

Witiiam Lower Carrrr was born at Stafford and educated at Derby
School, where he distinguished himself in Natural Science. On leaving
school he commenced work in a bank, but having a strong desire for
theological studies he entered as a student at Springhill College,
Birmingham, matriculating with first-class honours at London
University. From Springhill he proceeded to Cambridge, having
coned an Exhibition scholarship at Emmanuel College, where he

gain took up Science classes and passed the Natural Science Tripos
Toston with honours, specializing in Geology. Leaving
Cambridge he spent some time at the Univer sity of Halle in Germany,

Obituary—James Watson. 383

and then returned to Springhill College for a final theological
course.

In addition to his pastoral labours, he was ever keen on scientific
research, and did some valuable original work. He was for many
years also the Honorary Secretary of the Yorkshire Geological and
Philosophical Society, editing its important journals and initiating
efforts for the study of fresh Fel ds in geology. He filled the office of
Recording Secretary to Section C (Geology) of the British Association
for the Advancement of Science, Scanlae all the annual meetings.

WILLIAM LOWER CARTER, M.A., F.G.S.

In 1908 Mr. Carter accepted the important position of Lecturer in
Geology and Crystallography to the East London College, a post
which he continued to retain until the time of his death, also
lecturing in Geography and Botany at various colleges and technical
institutes in London. In this sphere he proved most successful,
being an indefatigable teacher to whom preparation was never any
hardship, and his pupils regard him not only with the esteem due to
a careful instructor but also with affection. It was while lecturing
on June 7 at Queen’s College, Harley Street, W., that he was seized
with cerebral apoplexy, from which he never rallied, but passed
peacefully away on June 19, 1918, at his residence, 9 Belmont Road,
Watford.

5 JOHN WATSON, M.A.; F.G.S.
Born 1842. DIED JULY 3, 1918.

Tur death of Mr. John Watson, of Bracondale, Cambridge, deprives
the geological world of a follower of the economic side of our science
ities possessed a very wide and full knowledge of the geology of
building-materials.

384 Obituary—Professor Voldemar Amalitsky.

Mr. Watson was born in the North of England in 1842, and spent
most of his life in Newcastle-upon-Tyne, where he became Managing
Director of the Gateshead Works for the manufacture of Portland
cement. Some years ago, on retiring from business, he removed to
Cambridge, where he resided until his death. Disdaining a life of
ease, he devoted his special knowledge and great energy to the
acquisition of an unrivalled collection of building-stones, ornamental
marbles, and other materials connected with building. These he
presented to the Sedgwick Museum, and spent his leisure in arranging
them and writing descriptive catalogues. Two of the catalogues
have already been published, and are well known to geologists and
to those connected with building, namely, British and Foreign
Building Stones and British and Foreign Marbles and other Ornamental
Stones. At the time of his death he was engaged in the preparation
of manuscripts for books on slates, limes, and cements, and it is
hoped that the material is in a state which will permit of its
publication in the not distant future.

Mr. Watson made many journeys at home and abroad in order to
render his collection as complete as possible, for he spared neither
time nor money in carrying out his self-imposed task; accordingly
the collection remains with us, a worthy monument to his labours,
specially valuable at a time when the claims for the teaching of
economic geology have become insistent.

In 1911 the University of Cambridge recognized the value of
his labours by conferring upon him the honorary degree of Master
of Arts.

He died as the result of an accident—a fall from a ladder—on
July 3. ;
Mr. Watson was greatly esteemed for his sterling character,
singular modesty, and charm of manner. His colleagues at
Cambridge will greatly miss the cheery ways and eager enthusiasm
of their old friend, butit is satisfactory to know that he had completed
so much of the work which he set out to accomplish, which was to

him veritably a labour of love.
J. EB. M.

PROFESSOR VOLDEMAR AMALITSKY.

News has just been received, by a letter posted in Petrograd on
March 2, that Professor Voldemar Amalitsky died suddenly from
heart disease on December 15/28, 1917, at Kislovodsk (North
Caucasus). Many friends in this country would wish to convey
their sympathy to his widow, who we trust may emerge safely from
these terrible times.

We hope later to publish a full notice of Amalitsky’s great work
in the discovery and rescue of numbers of entire skeletons of
Permian (or Triassic) reptiles from the banks of the Northern
Dwina, near Archangel, in Northern Russia, 1904 and earlier (see
Grou. Mae., 1905, p. 514).

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SEPTEMBER, 1918.

, Ce INE SEN ING eS 2
I. ORIGINAL ARTICLES. Page REVIEWS (continued). Page
Laterite in Western Australia. By Flathead Coal Area, British
Professor W. G. WOOLNOUGH, Columibiaks sec eeaae eee nee 42
D.Sc., F.G.S. (With two Text- Minerals used in Arts and In-
FL QUE SS) Pee eee hartge eccrelanat crete 385 dustries: Graphite. By P. A.
Pleistocene Glaciation of New Zea- NAVEHORAKSTE! pMeticrah abeyseistssieh enn ae 420
land. By Professor JAMES PARK, Asbestos. By P. A. Wagner......... 421
TGS (UR IEIG DUI a) sb sdoonssanc 394 | The Karroo System. By A. L. du
Recent Geological History of the ANOT RS nqackboascanc ee maR mer aaHs tae te ae 421
| Baltic and Scandinavia. By Sir
| Henry HowortH, K.C.1.E., III. REPORTS AND PROCEEDINGS.

AlBigsicy IoSb/No5 JOKES, (Cons s See
Oe cae

The Stratigraphical Position of the ee ike OG) ERSY ce spl seers near RRR fal
Coralline Crag. By Ne July 3) WAS cdot ROGER Renae Sapna 422
HARMER, F.R. Met. Soc., F.G.S.

(With a Text-figure.)............... 409 IV. CORRESPONDENCE. |

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Il. REVIEWS. V. OBITUARY.

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NEV SERVES. DECADE Ville NOL Wi

No. IX.—SEPTEMBER, 1918.

ORIGIN AL AI AES ER ES are ( atig
NAME eo
1.—Tuer PrysrograrHic SIGNIFICANCE OF ftir IN WESTERN
AUSTRALIA.

CAN

By W. G. WoounouGH, D.Se., F.G.S., Professor of Ges. University of
Western Australia.
URING the last six or seven years a series a zafdbote’ papers
bearing on the origin of laterite has appeared in the Grotoercar
Macaztne.! The conclusions arrived at have been somewhat div erse
and contradictory. Dr. Fermor, on the one hand, regarded the
laterites of India as residual in character, and believed that they
represented the insoluble residues left in the process of rock
weathering after the soluble constituents had been removed in
solution. Mr. Simpson, at the other extreme, suggested that they
represented the soluble material, leached out of the subjacent rocks
during weathering under peculiar conditions, and deposited as a
chemically-formed “rock by precipitation at the surface of the earth.

Mr. Holmes and Professor Lacroix both appear to hold much the
same view as that enunciated by Mr. Simpson. The fact that
Dr. Fermor, in his admirable review of the work of Lacroix, does
not dissent from the statements of the latter, suggests that Dr. Fermor
and Mr. Simpson may really hold very similar views, and that the
apparent differences may be, after all, due to method of expression
and not to actual divergence of opinion.

It is quite possible that different methods of formation may occur
under the widely different conditions of climate and geology exhibited
by the various regions from which laterite has been described.
Whether this is so or not, the author is wholly in agreement with
Mr. Simpson in his explanation of the chemistry of laterite formation
in Western Australia, but desires to go further and to extend and
amplify the physiographic processes involved in the genesis of this
peculiar rock.

A very brief summary of the physiography and geology of the
south-western portion of Western Australia? will assist in the
understanding of the problem. ‘he most important feature of all is
the Darling Range Escarpment. This extends asa straight line for
at least 200 miles in a north and south direction from near Gingin

1 Notably L. L. Fermor, ‘‘ What is Laterite?’’: Grou. Mac., 1911,

pp. 507-16, 559-66 ; HK. 8. Simpson, “* Laterite in Western Australia”? : i bid.,
1912, pp. 399- 406; A. Holmes, “‘ The Laterite Deposits of Mozambique ”’
ibid., 1914, p. 529; L. L. Fermor, “The Laterites of French Guinea”? : ibid.,
1915, pp- 28-37, 77- 82, 123-9.

2 For a more detailed account see J. T. Jutson, Bull. No. 61, Geol. Sury.,
Western Australia.

DECADE YI.—VOL. V.—NO. IX. 25

386 Prof. W. G. Woolnough—Laterite in W. Australia.

(30 miles N.N.E.)1 toa point near Capel (110 miles 8.S.W.). These
points do not mark the limits of the feature in question, but beyond

MAP OF
WESTERN AUSTRALIA

os

pe a

Sarceis™

x ole on

\
‘ Coo \gerdie
\ Southern! Cross

errs |
Nore a
=

War y) KE r
3a
¥
cal SITS sok “9 g 4
Yoon bala sey,
ng

FIG. 1. Dy of Ween ay showing positions of places mentioned in
the text. In order to avoid confusion places in the immediate vicinity of
Perth have not been inserted. Helena River is a tributary of Swan River.
Brunswick and Preston Rivers are tributaries of Collie River.

1 For simplicity in finding localities on the map the approximate direction
and distance from Perth will be given in each case.

Prof. W. G. Woolnowgh—Laterite in W. Australia. 387

them the structure becomes complicated in marked contrast to its
extreme simplicity within the specified zone. The escarpment has
an extremely uniform altitude of about 900 feet above sea-level, and
marks the boundary between the Coastal Plain on the west and the
‘‘ Darling Range” on the east.

The Coastal Plain is very uniformly about 15 miles wide and
consists almost exclusively of sandy deposits of recent age. In the
neighbourhood of Perth these have been proved by artesian bores to
extend to a depth of at least 2,000 feet below sea-level. The surface
of the Coastal Plain is undulating, but does not, asa rule, rise to more
than 150-200 feet above sea-level.

The name ‘‘ Darling Range”? is really a misnomer for the highlands
to theeast of the scarp. These highlands form actually one of the most
perfect peneplainsin the world, and they will be referred to, therefore,
throughout this communication as the Darling Peneplain or Darling
Plateau. The surface of this unit is gently undulating for the most
part. Its average altitude increases gradually as we proceed east
and north, so that it is 1,046 feet at Merredin (145 miles E.N.E.),
1,400 feet at Coolgardie (320 miles E.N.E.), 1,506 feet at Laverton
(450 miles N.E.), 1,755 feet at Sandstone (3830 miles N.N.E.), and
1,708 feet at Meekatharra (400 miles N.N.E.). The plateau is built
up almost exclusively of extremely ancient crystalline rocks, some of
which are of acid composition (granites and gneisses), others of which
are basic (quartz-dolerites, epidiorites, ‘‘ greenstones,” etc.).

The escarpment is deeply trenched by streams which flow westwards
into the Indian Ocean. ‘he larger streams like the Swan, Helena,
Murray, Brunswick, Collie, and Preston, have reached base level
and have begun to widen their valleys just within the edge of the
plateau. The smaller streams and all but very insignificant stretches
of even the larger ones are, however, strikingly juvenile throughout
their intra-plateau portions. The whole of the western part of the
plateau is therefore intensely dissected and roughened by deep
narrow gorges. This is an important point to remember in discussing
the origin of the laterite. The zone of intense dissection is not very
wide, and, from Chidlow’s Well (20 miles E.N.E.), the levels on the
Eastern Goldfields Railway (to Coolgardie, Kalgoorlie, and Laverton)
indicate clearly the very slight relief of the area. Very rarely indeed
do depressions fall more than about 200 feet below the average level
of the surrounding country.

In the western zone of the plateau crystalline rocks in situ are met
with only in the valleys of the young rivers which have dissected the
surface. As soon as the peneplain level is reached the surface is
covered with a dense shield of laterite. As Simpson has pointed out,
the composition of the laterite varies sympathetically with that of the
underlying bed-rock; where the latter is granitic the laterite is
aluminous, where it is basic the laterite is ferruginous. In every case
the laterite, which is usually solid for a thickness of from 8 to 6 feet,
rests on a bed of kaolin. ‘The basement is very well exposed in some
of the railway cuttings, as, for instance, at Baker’s Hill (80 miles
E.N.E.), Hoddy’s Well (50 miles E.N.E.), Gooseberry Hill (10 miles
\.), and other places. The leaching of the rock has been so thorough

388 Prof. W. G. Woolnough—Laterite in W. Australia.

that the residual material is suitable for the manufacture of fire-
bricks. These, and brick arches for locomotive fire-boxes, are made
at Smith’s Mill (15 miles E.N.E.) and at Clackline (50 miles E.N.E.).
That the leached material is in situis very clearly demonstrated by
the preservation of minute aplite, pegmatite, and quartz veins
through it (as at Hoddy’s Well), and by the slight differences in
colour and consistency of the kaolin caused by the presence of basic
dykes through the granites. Some of these structures are only
a fraction of an inch in thickness; yet, though they have been
cracked into short sections, they preserve their continuity for
considerable distances. This is clear proof of the residual character
of the pipeclay foundation of the laterite, and indicates that the
volume of the pipeclay is very little less than that of the rock from
which it has been derived.

The laterite capping, as above noted, is usually from 3 to 6 feet thick.
In many instances where it has not been stripped off (for railway
ballast or road-making) the apparent thickness is greater because of
the collapse of the capping through erosion of the pipeclay substratum
at the edge of the outcrop. The laterite extends as larger and
smaller continuous cappings over the plateau areas which have not
yet come under the action of the dissecting streams. These cappings
are thus the residual portions of a once continuous sheet which
mantled the entire peneplain surface.

As we pass inland, beyond the area which is in process of active
dissection by coastal streams, into the broad extent of undulating
country forming the wheat belt of Western Australia, the distribution
of crystalline rock and laterite becomes different from that near the
western scarp of the plateau. The characteristic elements of the
land surface are broad, exceedingly mature, meridional valleys
alternating with low ridges. The valleys are heavily aggraded, and
the slopes are well mantled with soil, though extensive outcrops of
granites and greenstones are also met with at intervals. The ridges
are partly of the same character as the slopes, that is, soil-covered,
but are rather more than half composed either of ‘‘ Sand Plain”’ or of
large granite outcrops. The latter (the granites) form immense flat
domes, sometimes several miles in circumference, and have played
a very important part in the exploration and prospecting of the
country. On their surfaces are found the ‘‘rock-holes” and
‘‘onamma-holes’’ whence the earlier travellers obtained their water
supplies. The ‘‘ Sand Plains” are extensive areas of light, friable
sandy soil, beneath which, at all events in many instances, occurs
a bed of sandy lateritic material. The perfect pisolitic structure of
the escarpment laterites is almost completely wanting in those of the
sand plain, though well-defined concretionary structure is plainly
discernible. Solid masses of concretionary laterite forming extensive
cappings of the higher residuals are not encountered through the
wheat belt.

Further east, again, the physiography alters once more. The
meridional valleys are no longer definite stream channels, but have
degenerated into strings of salt lakes, whose floors, consisting for the
most part of comparatively insignificant thicknesses of detrital

Prof. W. G. Woolnough—Laterite in W. Australia. 389

material, are covered with crusts of salt and gypsum. The ridges
are, to a large extent, very rocky, and are frequently, but not always,
capped by lateritic material. This laterite is again very different in
general aspect from that which mantles the western zone of the
Darling Plateau. It is not decidedly pisolitic, but is rather cellular
and cavernous in structure. Nevertheless, the effects of concretionary
action are abundantly apparent throughout, and it shows every
evidence of a mode of origin generally similar to that insisted on by
Simpson. The author is by no means so familiar with these eastern
areas, distant from Perth 200-400 miles, as he would like to be, but
quite numerous traverses of the area have beenmade. In the western
part of the Goldfields Belt, near Southern Cross (205 miles E.N.E.),
for instance, the laterite in many cases, if not always, lies directly
on the surface of the crystalline rocks and schists, without the
intervention of any extensive layer of thoroughly leached pipeclay.
The rock, however, 1s deeply weathered, and the lower parts of the
laterite crust represent an impregnation of the very much rotted
original rock.

Further east, again, for instance, at Coolgardie (220 miles E.N.E.),
there is a partial return to the conditions of occurrence met with in
the Darling Plateau, The ‘‘ Red Hill” in this town is a very typical
laterite-capped butte, strongly concretionary rock resting on a well-
leached substratum, but one which is much more ferruginous than
that which is characteristic in the extreme west. Throughout the
Eastern Goldfields, so far as I have been able to observe, there is very
little tendency to laterite formation on anything but the basic rock
types. Granites, quartzites, or siliceous schists are entirely free
from laterite coverings. In these eastern areas laterite cliffs often
constitute what are known as ‘‘ Breakaways”’, which form the shores
of the salt lakes.

This brief and inadequate outline of the physiographic conditions
under which the laterite is distributed in the south-western portion
of Western Australia, indicates that the problem of its formation is
more complicated than Simpson has shown. The author is wholly
in accord with him with regard to the chemistry of the process of
laterite formation, namely, by leaching of the soluble constituents of
the subsoil, transportation of the materials in solution to the surface
by capillarity, and precipitation of certain of the dissolved matters
there, through alternate saturation and desiccation of the subsoil
consequent on seasonal alternation of extremely wet with intensely
dry seasons. Simpson, however, appears to believe that the laterite
may have formed on the surface of the Darling Peneplain, and it is om
this point that I disagree with him. The drainage of the area is far
too perfect at the present day to admit of the upward leaching of
solutions to any considerable extent. The rapid fall in the level of
water in wells sunk through the laterite capping on the plateau,
even at very considerable distances from the nearest deep valley,
indicates the effectiveness of lateral drainage under existing
conditions. In November and December, 1916, the author noted
a fall in the level of one such well (at 50 miles on the Perth—Albany
road) of upwards of 30 feet in six weeks.

390 Prof. W. G. Woolnough—Laterite in W. Australia.

The thesis I wish to establish is that the laterite was produced
- under.peneplain, not plateau, conditions, that is, when the land surface
stood at a very slight elevation above sea-level. Youthful streams
cut down their valleys to base-level before they begin to widen them
at all sensibly. Hence the development of maturity of river erosion,
that is, the evolution of a peneplain, can be completed only at a slight
altitude above base-levei, which in this case was undoubtedly
sea-level.

With a very gentle gradient mechanical transportation of sediment
would be insignificant, and even in solution the lateral movement
of material would be extremely slow. Chemical weathering, however,
would be strongly favoured, and, given alternations of wet and dry
seasons, the conditions for laterite formation, postulated by Simpson,
would be ideally fulfilled.

If this view is correct it follows that the importance of laterite,
from an historic point of view, is greatly enhanced. It owes its
present position on the summit of the plateau to the uplift of the
peneplain, the criteria for such an elevation along the Darling
Escarpment, with down faulting of the coastal strip towards the
Indian Ocean being complete in every particular. Hence it follows
that the laterite capping serves as a stratigraphic horizon of no mean
value. If we find areas of laterite markedly elevated above, or
depressed below the general laterite level, we have a prima facie
reason to suspect earth movement as a cause. In applying this
principle, however, it is important to remember that the peneplain
was never a perfect plane, but was always an undulating surface.
Under these circumstances certain initial differences of level of the
laterite capping must be postulated. In the Darling Plateau area it
seems probable that these differences of level were of the order of
200 feet.!

Another possible source of error is the fact, mentioned by Simpson,
that considerable areas of redistributed laterite occur. When due
allowance has been made for these possible sources of error, a sufficient
number of outstanding cases has come under notice to indicate that
the importance of the general principle has not been overrated, and
that extraordinary differences of laterite level in adjacent areas indicate
block faulting. In most instances other criteria of faulting may be
discovered which convert probability into certainty. As examples
may be cited the occurrence along the foot of the Darling Range
Scarp, in the immediate neighbourhood of Perth, of isolated
remnants of a laterite-covered shelf or step. At Greenmount and |
Ridge Hill (10 miles E.), where two railway lines enter the scarp,
this shoulder of laterite is prominent, while it can be detected at
least three points immediately to the south of those mentioned.
At Armadale (15 miles 8.E.) and Waroona (60 miles 8.) similar
areas of low-level laterite occur. From these occurrences I believe
we may suspect that the faulting of the Darling Range Scarp is of
the nature of a step fault and not simply a single fault (see Fig. 2).

1 The difference in altitude of Chidlow’s Well (30 miles E.N.E.) and

Wooroloo (37 miles E.N.E.) on the eastern railway, both on the laterite
““level’’, amounts to 256 feet.

Prof. W. G. Woolnough—Laterite in W. Australia. 391

In this case the collateral evidence is not so strong as it is in some
others. The Collie Coalfield (100 miles S.8.E.) is a Senkungsfeld in
which a wedge of Permo-Carboniferous Coal-measures has been let
down into a trough amongst the granites. This faulting was no
doubt pretty ancient, but the movement has evidently been rejuvenated
in very recent geological time. Here we have a difference of level of
the solid laterites of 213 feet between Yokain and Penrith on the
railway line immediately west of Collie. This difference is not
enough per se to establish the faulting, but other criteria, both
geological and physiographic, taken in conjunction with the laterite

zz SE
Zi Ze
ae ion an
ee < a.
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O Sa au = aa
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Scales Horizontal _ emule eNegilcall eOOudn,

Fie. 2.—Sketch-section of the Darling Range Escarpment at Armadale,
Western Australia (slightly generalized), showing relation of high-level

and low-level laterites to possible slip- faultings. Laterite is shown black,
and its thickness is exaggerated.

evidence, are amply satisfactory. Again, at Brookhampton (115 miles
S.), a sudden jump of 200 feet in the laterite level was what first
attracted the author’s attention to a very decided recent fault there.
Within the wheat belt and the Kastern Goldfields no test as to the
applicability of the theory has been made. Inthe Eastern Goldfields
Maclaren believes that the laterite is still growing. While this may
be so at isolated and favourably situated points it is quite possible
that the statement cannot be substantiated generally. In the south-
west it is found that many of the coastal streams have heavy cappings

392 Prof. W. G. Woolnough—Laferite in W. Australia.

of laterite on their alluvial terraces in the neighbourhood of the
_ highlands. This is markedly the case, for instance, with the Preston
River at Donnybrook (210 miles 8.). It is quite possible that
laterite may be actually forming at this and similar points, and the
formation may be explained as follows :—

Most of the streams in question are fed by the subsoil drainage
which flows beneath the laterite capping of the plateau. Their
waters are, even in the wet season, hard and somewhat mineralized.
As the dry season advances they all, with few exceptions, become
unpleasant for drinking purposes. Many of them deposit iron
abundantly, and give rise to iridescent films of iron oxide on the
surfaces of pools. These films have been mistaken repeatedly for
indications of petroleum. When the active flow of the streams
ceases early in the summer, capillary action through the porous
alluvium of the terraces may induce the upward concentration of the
dissolved salts and give rise to normal laterite. It is to be noted
that some of these river-terrace laterites are much more like the
ordinary plateau laterite than are the detrital laterites. For this
reason it may be advantageous to recognize a third river-terrace ty pe
of laterite in addition to the two varieties (solid high-level type and
secondary detrital type) defined by Simpson. This mode of occurrence,
if it is correctly understood by the author, may possibly explain the
very common occurrence of laterite in the breakaways on the shores
of salt lakes in the Eastern Goldfields.

The author doubts whether the occasional torrential rains of the
arid areas are competent to produce laterite as supposed by Simpson.
The latter authority (loc. cit., p. 401) mentions falls of 3°30 inches of
rain at Mulline in one day and of nearly 4 inches at Coolgardie in
two days. It is the universal experience that such torrential down-
pours cause comparatively little saturation of the soil. Even in verv
porous sandy areas the proportion run off to soakage is very high, and
it is extremely doubtful whether the cycle of events necessary for
laterite formation could follow such sudden downpours as those
mentioned. Matters are quite otherwise when the rainfall is seasonal
in character, asis very typically the case in the areas nearer the coast.

To explain the heavier laterization of the goldfields than of the
wheat belt I would suggest that the question must be referred back
to the previous geographic cycle. It has been shown that there has
been a net uplift of the Darling Peneplain of nearly 1,000 feet on the
west, and probably of considerably more on its eastern side. If the
theory of laterite formation under low altitude conditions is correct
it follows that the goldfields laterite must have been formed when
the land stood much lower than it does now.

The presence of marine fossils at peneplain level at Norseman
(350 miles E.S.E.) indicates that, at no very distant epoch, the sea
extended much further inland than the present head of the Great
Australian Bight. It is well known that in comparatively recent
geological time the climate of Central Australia was much moister
than it is at present, and it is reasonable to suppose that a much
increased humidity was experienced in the Goldfields area. Under
these circumstances it is very easy to account for the extensive

+

Prof. W. G. Woolnough—Laterite in W. Australia. 393

laterite formations of the region. The wheat belt was probably
sufficiently distant both from the known coastline on the west and
from the problematical coastline on the east to experience so light
a rainfall as to preclude extensive laterite formation of the normal type.

Before leaving the subject of origin of laterite it may be of interest
to point out that somewhat similar formations abound in Australia
under conditions pointing very conclusively to conditions of formation
identical with those laid down by Simpson forthe Western Australian
laterite.

In South Australia, where eruptive rocks are comparatively rare,
and where marine sediments and schists predominate, the place of
laterite is taken by almost ubiquitous ‘‘ travertine”’’, an impure lime-
stone with highly perfect concretionary and pisolitic structures
encountered under conditions quite similar to those of the western
laterite.

Throughout the area occupied by the highly siliceous Upper
Cretaceous Desert Sandstone formation in Central Australia, very
widespread concentration of silica has followed a course identical
with the concentration of lateritic materials. The result has been
extensive opalization of the sandstone and the formation of
porcellanites and quartzites.

Particularly in the wheat belt and goldfields of Western Australia
it is usual to find granite outcrops ‘‘ case-hardened ” to adepth varying
from a few inches to several feet. This phenomenon is evidently due
to a superficial concentration of materials derived from the somewhat
soft and crumbly internal portion of the rock, and it is to be explained
in the same way as the production of laterite. This ‘‘case-hardening”’
of granite outcrops is an important factor in the production of the
‘Conamma-holes”’ or natural tanks in which so much of the scanty
water supply of the arid interior is conserved.

SUMMARY.

The author is of opinion that—

1. Laterite in Western Australia is formed by the leaching of
subsoil salts during seasons of heavy rainfall, and capillary attraction
of the solution to the earth’s surface during intervening dry periods ;
the dissolved matter being deposited in a concretionary fashion in the
surface layers of the soil.

2. Laterization can occur only in areas where drainage is almost
at a-standstill. This usually involves the existence of a peneplain
almost at sea-level.

3. High-level laterite is a criterion of elevation of the land.

4. Difference in laterite level suggests faulting, which can often
be proved by collateral evidence.

5. Outstanding differences of opinion with regard to broad features
in the physiography of Western Australia may be reconciled by
recognition of the essentially low-level nature of laterite.

394 Prof. J. Park—Pleistocene Glaciation, New Zealand.

I1.—P.eisrocene Guacration or New Zeatanp.
_ By Prof. JAMES PARK, F.G.S., University of Otago, Dunedin, New Zealand.
_ (PLATE XIV.)
N the June issue of the GuoLoercaL Macazine’ for 1917 there
appears an article by Mr. C. T. Trechmann, D.Sc., F.G.S., on
“The Glaciation Controversy in New Yealand’? in which he
traverses my views as to the extent of the Pleistocene glaciation
of this Dominion. I regret that my recent journeys to the Isle of
Pines and Cape Yorke Peninsula and the irregularity of the oversea
mails arising from the war conditions have prevented an earlier
reply. Mr. Trechmann deals first with the glaciation of the
North Island. He says it seems to him that the question of
the glaciation cf the North Island stands or falls with the origin
of the striations on the large andesitic boulder lying near Mangaweka
in the Rangitikei Valley (see Plate XIV). He selects these striations
as the sole criterion of former glaciation, and argues that ‘‘if the
scratches are not glacial the boulder is not glacial, and if this
boulder is not glacial none of the others are glacial, and the chief
evidence for a glaciation of the North Island fails”. Asa matter
of fact this great striated boulder was not discovered by me till
1915,” or some five years after the close of the glaciation controversy
between Dr. P. Marshall and myself.* Its existence was unknown
in 1909. At that time I relied on other evidences of glaciation that
Mr. Trechmann passes over with little or no comment.

I will briefly summarize the other evidences. In 1909* I dis-
covered at Turangarere, in the Hautapu Valley, a great tumbled pile
of angular and semi-angular boulders of andesite that range in size
from 1 to 6 feet in diameter; still greater piles and larger masses at
Mataroa and Taihape, and a smaller pile at Utiku. These boulders
are foreign to the Hautapu basin, which is composed of Pliocene
marine Glays that are interbedded with a few thin beds of shelly
limestone. The only possible source of these andesitic masses is the
great volcano Ruapehu (9,000 feet), which is separated from the
Hautapu Valley by the Wangaehu Valley and the Waiouru plateau-
like ridge that forms the divide between the Wangaehu and the
Hautapu Rivers.

The present distribution of the andesitic piles would tend to show
that, when originally deposited, they extended across the Hautapu
Valley, and formed barriers that have since been breached by the
Hautapu River. The smaller material was resorted during the
process of excavation, and spread out as gravelly deposits along
the present course of the river.

In 1909 I postulated that the agent which transported the
andesitic material across the Wangaehu Valley and the Waiouru
divide, and deposited it in widely separated piles in the Hautapu
Valley at distances ranging from 20 to 40 miles from its source, was
a Pleistocene extension of the existing Ruapehu glacier.

1 GEOL. MAG., Vol. IV, pp. 241-5, 1917.
Trans. N.Z. Inst., N.S., vol. xlviii, pp. 1385-7, 1915.
Trans. N.Z. Inst., vol. xlii, pp. 589-612, 1909.
Trans. N.Z. Inst., vol. xl, pp. 575-80, 1909.

= 0

Prof. J. Park—Pleistocene Glaciation, New Zealand. 395

In 1915,! near Mangaweka, on the west side of the Rangitikei
River, a few miles below the junction of the Hautapu, and nine
miles farther down than the lowest previously known pile of
andesitic blocks, I discovered the solitary conspicuously striated
andesitic boulder to which Mr. Trechmann refers. This block lies
on the Rangitikei terrace at the foot of a ridge of Pliocene marine
clays, 1,070 feet above sea-level. It measures about 14 X 6 X 55
feet, and weighs over 37 tons. The underside and one end for a
height of two feet are smoothed, rounded, and scored with innumer-
able fine strie and hundreds of deep grooves, most of which run
parallel with the longer axis of the block (see Pl. XIV, Fig. 2). The
smoothed and striated surface has an area of some 90 square feet.

Mr. Trechmann always refers to the markings as ‘‘scratches”’.
He makes no reference to the deeper grooves which occur so plenti-
fully. By this omission and the constant reference to scratches,
he unconsciously conveys an erroneous impression as to the extent
and nature of the markings. And this minatory impression is not
diminished when he states that the surface of the boulder is much
decomposed and weathered. As a matter of fact all andesites are |
prone to weather rapidly ; andif the striae and grooves are Pleistocene,
as I contend, the wonder is that weathering has permitted any trace
of the striz to remain. In my opinion, the preservation of the
markings is due to the protection afforded by the clays and soil on
which the boulder rested, and in which the underside is still
partially embedded.

Mr. Trechmann says that the decomposed surface can almost be
scratched with the finger-nail, and that scratches can easily be made
on it with a knife blade. The ‘‘scratches’’ could, in his belief,
easily have been made by the boulder moving downhill over
gravelly soil or ofer other stones. According to this view the
decomposition of the surface had already taken place before the
boulder began its downhill movement. As this seems to be
the essence of his contention, I have again examined the boulder and
find that in all the deeper grooves the skin of decomposed rock
conforms to the contour of the groove. Clearly the weathering
took place after the grooves were formed, and not before, as
Mr. Trechmann’s suggestion would seem to imply.

The smoothing, scoring, and grooving of a rock mass by its down-
ward movement under the influence of gravity is perhaps not
accomplished with the ease assumed by Mr. Trechmann. There is
no. evidence that the Mangaweka erratic does not now lie in the
place where it was left by the agent which carried it from Ruapehu.
The old flood-plain of the Rangitikei is about 250 feet above the river
terrace on which the boulder lies. Even if we assume that the
boulder did at one time lie on the surface of that old plain it will,
I think, be difficult to prove that its downhill movement could
produce the smoothing and grooving we now see on the under
surface of the block. It seems to me that when the excavation of
the old flood-plain reached the boulder one of two things would

1 J: Park, Trans. N.Z. Inst., vol. xlviii, p. 136.

396 P. rof. J. Park—Pleistocene Glaciation, New Zealand.

happen. Hither the boulder would incontinently tumble down to
_ the present level, or it would slide down if the slope of the terrace
face exceeded the angle of rest. When a heavy body descends on
a gravel face, the material in contact with the body moves downhill
at the same time, and this flowage would not, in my belief, lend
_ itself to the smoothing and grooving of the heavy body.

The large size of this solitary erratic, its transportation across the
Waiouru divide, its great distance from its source, its grooved and
striated underside, and the existence of a considerable glacier on
Mount Ruapehu, the place from which it originally came, have led
me to the conclusion that it was carried to its present site by a
Pleistocene extension of the Ruapehu Glacier that flowed down the
Hautapu into the Rangitikei Valley.

Further, I know of no agent but a glacier that could transport and
pile up the tumbled masses of andesitic rock that occur at widely
separated points of the Hautapu Valley.

Turning to the South Island Mr. Trechmann deals mainly with the
Taieri or Henley deposit. He says that in his opinion this drift is
not glacial, and concludes that the glaciation was alpine and not of
a regional type. This great deposit has been shown by the careful
mapping of Mr. A. G. Macdonald, B.E., to extend from Saddle Hill,
near Dunedin, to the Clutha Valley, a distance of some 32 miles.
It occurs as a sheet on the west side of the coastal range that
separates the Taier1 Valley from the sea. It rises from sea-level to
a height of 1,000 feet, and in many places forms conspicuous cliffs.
near the summit of the range. A distinctive feature is its proneness
to form great landslides. Its thickness in the Taieri Gorge has been
estimated at 1,500 feet, but this is probably an underestimate. The
dip is to the westward at low angles. The lower portion is com-
posed of rudely bedded angular fragments of mica-schist and an
occasional large angular block of the same rock. The upper portion
of the deposit Howe little sign of bedding, and generally the
material is coarser and large angular blocks more plentiful than in
the lower portion.

As Mr. Macdonald’s maps! clearly show, this deposit near Dunedin
rests on the Oamaruian (Miocene) Coal-measures, at the Taieri
Gorge on Paleozoic mica-schist, at Milton on the Oamaruian Coal-
measures, and further south on Kaitangatan (post-Senonian, probably
Danian) Coal-measures. Although mainly composed of mica-schist
blocks, slabs of limonitic penetra Tai: from the Oamaruian series.
are not uncommon in the deposit on the range near Milton. The
Taierl deposit was always considered by Mr. J. T. Thomson and
Captain Hutton to be a glacial moraine, and Mr. McKay reported
that it looked like a glacial deposit. I have described it as fluvio-
glacial, and on no oceasion during the glacial discussion in 1909 did
Dr. Marshall challenge its glacial origin.

Mr. Trechmann states thet he was struck with the dissimilarity of
this deposit to any glacial moraine that he had ever seen. ‘To this
I would say that the rudely stratified fluvio-glacial drifts in the

1 These manuscript maps are filed in Otago University. They were prepared
in connexion with a research scholarship held by Macdonald.

ie he
i
\ ; ; . M b, ©
: i ‘ vf K 4
i
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i H *
i
i {
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is Lan
e ; : ne mn 4
. 7]
(
i

GEOL. Maa. 1918. PLATE XIV.

>

Fic. 1.—Great erratic of Andesite near Mangaweka, North Island, New Zealand.
,, 2.—A portion of surface showing grooves and strie.

Sur H. H. Howorth—Geological History of the Baltic. 397

Cromwell and Manuherekia basins in Central Otago and the out-
wash drifts at the end of the Tasman glacier present many features
in common with the Taieri Moraine.

He refers to the fault dislocations of the Blue Spur deposits; and
expresses the opinion that they appear to be much earlier than the
Pleistocene, but he gives no data in support of this view. |

Mr. Trechmann says there is no evidence of transported erratics at
the foot of the Otago Peninsula and Banks’ Peninsula. At the
former I know of no erratics, but there are deposits near Dunedin
that if not glacial are otherwise difficult to explain. I have never
contended that an ice-sheet extended to the foot of Banks’ Peninsula,
or even covered any portion of the Canterbury Plains. What I
have postulated was that glaciers descended to the existing sea-
strands where these strands coincided with the Pleistocene strands,
as on the east coast of South Otago and in South Westland. The
Pleistocene strand of South Canterbury followed the foot-hills that
form the western boundary of the plains. At the maximum Pleisto-
cene extension the Canterbury Plains were only in the early stage
of formation. Perhaps the fault that I have been misquoted on this
question lies at my own door. When discussing the Pleistocene
extension of our glaciers I thought it would be self-evident that this
glaciation could only refer to New Zealand as it existed in the
Pleistocene.

Reference is made by Mr. Trechmann to the freshness of the
glacial phenomena in the Alpine regions of New Zealand. The
glaciation there is that of to-day or yesterday. In my belief it
would-be surprising to find the same freshness among the glacial
phenomena developed during the Pleistocene extension of the
glaciers.

In conclusion, let me say that Mr. Trechmann was a most welcome
visitor to the shores of New Zealand. His paleontological researches
have thrown valuable light on some problems that long baffled New
Zealand geologists; and for this reason I regret that I am unable to
see eye to eye with him on the glaciation question.

EXPLANATION OF PLATE XIV.

Fic. 1.—Reproduction from a photograph of large Andesitic Boulder near
Mangaweka in the Rangitikei Valley, New Zealand. Measures 14 x 6 x
' 55 feet; weight over 37 tons.
Fie. 2.—Portion of the surface of the same Boulder, showing grooves and
striations. Reproduced by permission of the New Zealand Institute from
the Trans. N.Z. Inst., vol. xlviii (N.S.), pp. 135-7, 1915.

IIl1.—Tuer Recent Gerotoeicat History or tHe Barric anv Scanpi-
NAVIA AND ITS IMPORTANCE IN THE Post-Trertrary History or
Wesrern Evrorpn.

By Sir Henry H. HowortH, K.C.1.E., F.R.S., F.S.A., F.G.S.
(Continued from the August Number, p. 367.)

E will now try and picture to ourselves how the circulation of
the water was affected by the breach in the land bridge.
We have seen in the earlier part of these papers that one of its effects

398 Sir H. H. Howorth—Geological History of the Baltic.

was that the southern and western part of the Baltic became
rapidly richer in marine forms. ‘This is because the Straits between
- Gjedserodde in the island of Falster and Darrserort on the mainland
of Mecklenburg form a great barrier to the eastern migration of the
marine mollusea, whose species increase greatly in numbers when we
pass westward of them. This seems to again point to the fact that
the inflow of salt waters into the Baltic from the North Sea passes
chiefly through the deeper Belts and not through the shallower
Sound, which is the chief outlet of the more brackish Baltic water.
On the other hand, the Swedish side of the sea remains poor in fauna
until we reach the latitude of the island of Saltholm, due partly to
its greater shallowness, which only allows a smaller proportion of the
incoming North Sea water to pass. Mr. Dickson, who has written
a great deal on the coasts and currents of the latter sea, argues that,
the rotation of the earth causes the outgoing water of the Baltic to
cling to the Swedish side. It is, at all events, plain that the part
of the Sound south of Saltholm is in its marine life to all intents
and purposes a part of the Baltic. North of Saltholm, as Oersted
has shown, the marine life becomes much richer. The wealtn of
life, however, is limited to the deep water in the middle of the
Sound, while the shallower water forming the littoral zone continues
to be very poor on both sides as far as the exit of the Sound into the
Cattegat. It seems plain that since the great submergence there has
been a certain slight uplift of the land along the south coast of Skane
and on both sides of the Sound; here again it is marked by a very
poor and littoral fauna which has crept into the waterway from the
Baltic. These later littoral beds lie on portions of sunken turf and
other subaerial deposits.

Let us now pass northwards into the Cattegat and compare the
marine life of this Gulf with that of the Baltic. The contrast is
graphically given in the following table which I take from Professor
Brandt's memoir ‘‘ Die Fauna der Ostsee’’ (Verhand. Deutsch. Zool.

Gesell., 1879, p. 10, etc.).
Centraland Eastern Gulf of

Cattegat. Kiel Gulf. Baltic. Bothnia.
Fishes : : se 75 40 230 5
Ascidia . ; 20 BY as ia
Mollusea . : 88 23 6 4
Prosobranchia_ . 85 ibe 3 1
Opisthobranchia — 23 2 —
Decapoda . : 55 Sey 2 (1)
Amphipoda Ave SLs} 18 11 5
Isopoda . : 41 7 7 3
Cirripedia . : == 3 il 1
Cheetopoda SoD 3 o) 1
Bryozoa . : 65 17 1 1
Echinodermata . 36 6 (2) -
Actinozoa . : 16 4 a =
Acalepha . : = 2 2 =
Hydrozoa . é 48 15 1
Spongia . : 26 13 — =

We will now turn to the more detailed features of the Cattegat.
It is divided very distinctly into two sections marked by their
respective contents. The line between the two runs through the

(Sioa va id a i Howorth—Geological History of the Baltic. 399

island of Laesd, which, as I showed in a former paper, is surrounded
by a shallow sea bottom and is covered with the debris of a
littoral fauna; and which it is generally thought was at a not
distant date joined to the mainland of Jutland. At all events it is
plain that we have in this southern section of the Cattegat a very
distinct marine sub-province which ought to be united, not with the
northern section, but with the Sound, and is marked notably by the
presence of a considerable number of shells which are absent in
the northern section.
The following shells are absentees there :—

GASTEROPODA. 9. Trophon truncatus.
1. Aclis ascarus. 10. Fusus (Neptunea) antiquus.
Petersen, however, thinks the 11. Scutellina fulva, vulgar.
dead shells so named found by Cattegat.
Collin at Hellebach may be Aclis 12. Chiton albus.
supranitida, which occurs in both Apparently only in the S. of
lists, see pp. 71 and 80. Cattegat Sound.
2. Parthenia spiralis.
Also found in the Limfiord, ib., LAMELLIBRANCHIA.
75. 1. Mytilus phaseolinus.
3. P. wmterstincta. A new shell in 8. of the Cattegat
Also found in the Limfiord, ib. only, and not found N. of Laesé.
4. Odostomia acuta. 2. Cardium fascratum.
Subfossil in the Virk Sound. Not found N. of Laeso.
5. O. unidentata. 3. Astarte borealis.
Also fossil in the Limfiord. In the W. Baltic and S. Cattegat ;
6. Triforis perversa. dead specimens W. of Laesé.

S.E. and S.W. of Laeso.
7.. Natica islandica.
8. Velitina levigata.

A. compressa or sulcata.
Cyprina islandica.

Ot He

The presence of those shells in the south, but not in the north, of
the Cattegat I would explain as probably due to the erratic history
of the great Danish gulf known as the Limfjord, which virtually
separates Jutland from Wendsyssel and which discharges itself into
the Southern Cattegat, of which it forms a kind of gulf.

Through the Limfjord the Cattegat has had an intermittent com-
munication with the NorthSea. Its eastern opening into the Cattegat
has always been open, but its western one into the North Sea has at
times been for a considerable period silted up and closed by a
cul-de-sac, as I mentioned in a previous paper (Grov. Mae., Dec. Wis
Vol. II, p. 11). The continual breaking down in the eighteenth and
nineteenth centuries of the narrow isthmus separating the Limfjord
from the North Sea occasionally flooded its western part with salt
water from the latter sea, thus raising its salinity to 18 per thousand.
This led to the importation there of a considerable number of North
Sea fish and of certain molluscs lke the oyster, Zapes pudlastra, and
the typical form of Cardiuwm exiguum, which does not live in the
eastern part of the fjord.

Morlot says the Canal of Agger by which the Limfjord entered the
North Sea had become so narrow that only small vessels could pass,
and it threatened to close altogether in 1859.

It is not impossible that a number of the shells occurring in the
Southern Cattegat and not in the Northern may have entered it from

400 Sir H. H. Howorth—Geological History of the Baltic.

the North Sea by way of the Limfjord during one of the intervals
when it was open at both ends. Others may have been brought in
accidentally by ships or otherwise.

So much for the absentees from the northern section. On the
other hand, the latter contains a considerable number of shells not in
the southern part.

On comparing Petersen’s lists of the shells from the two sections
of the Cattegat I find the following absentees from the southern
area :—

GASTEROPODA. LAMELLIBRANCHIA.
1. Scalaria tortosa. 1. Pecten maximus.
2. S. Trevellyana. 2. Mytilus Adriaticus.
3. S. lactea. 3. Modiolaria discors.
4. Volvula acuminata. 4. Nucula decussata.
5. Philine pruinosa. 5. Cardwum Norwegicum.
6. Acera bullata. 6. C. nodosum.
7. Lacuna pallidula. 7. C. edule.
8. L. dwaricata. 8. Lucinopsis undatum.
9. L. membranacea. 9. Isocardia cor.
10. L. meonspicua. 10. Venus fasciata.
Il. L. parva. 11. Dosinia exoleta.
12. Natica Montagu. 12. Tellina pusilla.
13. Capulus Hungaricus. 13. 7. tenwwis.
14. Fusus propinquus. 14. Solen ensis.

. Mactra stultorum.

. Thracia convexa.

17. Trochus nuliigranus. . Cochlodesma (Triforis?) perversa.
18. Nacella pellucida. . Lyonsia Norvegica.

19. Dentaliwm (Antalis) entale. 19. Neera cuspidata.

20. Chiton ruber.

lt is plain that while the southern section of the Cattegat ought
zoologically to be joined with the Sound, the northern part ought to
be united with the Skagerack and the Christiania Fjord.

The reasons for the disparity in the contents of the two sections of
the Cattegat is probably the absence of the necessary quantity of salt
in the waters of the southern section. It may be also due partly to
the fact that the waters of the latter are not deep enough, the
greater part of it being in fact much shallower than the northern
part. Let us now return to the raised beaches of the Cattegat. In
them there is a marked contrast between their contents and the
living fauna of the great waterway.

I will now giye a list of the shells which have occurred in the
raised beaches fan kitchen-middens. Those which are rare and only
occur occasionally are marked with an asterisk.

pp
ON

ee
DIRE’

15. Mangelia costata.
16. M. nebula.

GASTEROPODA. Cerithiwm reticulatum.
*Odostonvia sp. *Utriculus truncatulus.
*Triforis perversa. * Neritina fluviatilis.

Litorina rudis. * Rissoa striata.
L. obtusata. R. membranacea.
LL. litorea. Acera bullata.

I. var. tenebrosa.

Hydrobia sp. LAMELLIBRANCHIA.
Lacuna inconspicua. Ostrea edulis.
*L. diwaricata. Mytilus edulis.

Nassa reticulata. Cardium exiguum.

Sir H. H. Howorth—Geological H iney of the Baltic. 401

Cardivum edule. ; Mellana (Macoma) Balthica.

Cardium var. *Corbula gibba.

Tapes pullastra. * Modiolaria discors.

T. aureus. Montacuta bidentata.
*T’..decussatus. Scrobicularia piperata.

This list differs from that given by Petersen in excluding Anomia
sgquamula and in retaining the name Scrobicularia piperata which he
called S. plana. It is perfectly plain that it only represents a
portion of the mollusca which were contained in the Southern
Cattegat when the raised beaches were deposited. Here the beaches’
are all at a very low level; they form, in fact, the concluding factors
of a series which occur at declining levels as we proceed southwards,
but were doubtless deposited synchronously at different points on the
coast from the Christiania Fjord to the Oresund, and represent only
the littoral series. It is, in fact, interesting to compare a small section
of the Gulf, namely, the Holbeck Fjord, where the following shells
are now living which have not occurred in the raised beds.

Buccinum undatum. Mactra subtruncata.
Tectura testudinalis. Thracia papyracea.
Abra alba. Saxicava rugosa.

A. nitida. Mya truncata.
Solen pellucida. M. arenaria.

What is much more important and interesting is the absence from
the present waters of the Southern Cattegat of a number of shells
with a wide distribution which abound in the raised beaches and
also in the kitchen-middens of that channel. I have described at
some length the remarkable consequences which have been deduced
from this absence in previous papers (Geox. Mag., 1905, pp. 12-15,
557-9). The general conclusion of the arguments of Petersen and
others is that the extermination or emigration of these molluscs was
due to the Baltic breach which flooded the Cattegat with an excess
of fresh water, and that this was coincident with the end of the
kitchen-midden people. It enables us to roughly date that event at
some eight or nine thousand years ago. The only fresh fact I need
mention is the addition of Pholas candidus to the list of migrants.
It is not now found nearer than the south of Norway.

By far the most interesting of these absentees are the oyster and
the three species of Zapes. Petersen named the beds in which he
found this series of shells Zapes beds, and he proceeded to argue that
when they were deposited the waters of the Southern Cattegat were
not only salter but probably also warmer than they are now, and
approximated more to those of the Skagerack than the North Sea.

In regard to the connexion of the Baltic with the Cattegat, it is
interesting that while the oyster has never occurred in the Litorina
deposits in the Sound, it has occurred in the deposits of the Great
Belt probably as far south as the Svendborg district (Aard. for Nord.
Oldk. Hist., p. 321, Copenhagen, 1888), showing that before the
Baltic breach the Belt was open from the north as far at least as the
latter place.

Morlot’s observations made long ago prove that the ‘“ kitchen-
middens’’ in many cases show signs of stratification and of having

DECADE VI.—VOL. V.—NO. IX. 26

402 Sir H. H. Howorth—Geological History of the Baltic.

been temporarily submerged. The kitchen-middens are ordinarily
3 to 5 feet, but in some places, as at Meilgard to Kolindsund, they
are 10 feet above the sea-level. Sometimes they are 1,000 feet long,
with a breadth of 150 to 200 feet. In the latter cases their surface
is undulating and often surrounds a depression free from them, as at.
Haveln, near Frederiksund, where the habitations of the natives
probably were. Their interiors in most cases are unstratified.
Others found on the shore and near the waves are covered with
sand and gravel, and the whole of their contents is more or less
stratified, as at Biledt near Frederiksund. It is clear that in such
cases the old mariners cooked their food on the shore after dis-
embarking, and the tide has afterwards rearranged them.
Morlot again called attention to the curious circumstance that
the kitchen-middens, the greater portion of whose contents are
stratified, yet consist of a heterogeneous mass of shells and other
debris deposited out of the reach of the waves, and sometimes have
a covering of rolled and stratified materials. This is only found up
to.a height of 14 to 18 feet above the sea-level, and always on the
slope facing the sea. At Oesterild in North Jutland this covering
attains a depth of a foot, and contains pebbles as big as the eggs of
a goose. Above the covering there is nothing. He concludes thus:
‘‘T] parait donc, que l’Age des Mjoekkenmoedding a été clos par
quelque catastrophe, qui a violemment agité les eaux de la mer,
laquelle a fait alors irruption jusqu’a une hauteur peu considerable
au dela de son domaine habituel. Ilse pourrait, que cet événement
eat eu lieu a une époque quelconque postérieure a la fin de l’age des
Kjoekkenmoedding. Cependant M. Steenstrup est disposé a le
considérer comme marquant le terme méme de cet age.’’!
Steenstrup also argued from another side that some uplift of the
coast had taken place since the deposit of the kitchen-middens, and
has shown that where the shores are low and shelving the midden
mounds occur at only a few feet above high tide mark, but they
reach a somewhat higher level when the coast is more abrupt. This
distribution of the kitchen-middens seems to show that the land has
not as a whole risen or sunk very much since they were deposited,
for they are not likely to have been deposited either very far from
the sea or at a great level above it. So much for the kitchen-
middens. Turning to the raised beaches containing the same
characteristic shells as the middens, namely, the Zapes beds, they
are found on each side of the Cattegat, both in Jutland and on the
Swedish side. They increase in number as we go northwards,
although of the same age. Large numbers of dead shells of the
Tapes also occur on the floor of the Southern Cattegat. In the upper
part of the Cattegat north of the island of Laeso we meet with a much
more abundant living marine fauna, which closely approximates to
that of the Skagerack and the Christiania Fjord, due doubtless to the
greater depth and salinity of its waters. In one respect in which
this approximation takes place there is no relationship whatever
between the two sections of the Cattegat, and the difference is

1 Morlot, ‘‘ Etudes Géologico-Archéologiques en Danemark et in Suisse’’:
Bull. Soc. Vaudoise, Sci. Nat., vi, No. 46, pp. 275-6, 1860.

Sir H. H. Howorth—Geological History of the Baltic. 403

fundamental and much more important. ‘This consists in the
presence in the northern part of a series of raised beaches of an
entirely separate class and which have not appeared in these papers
before. They are the so-called Yoldia beds. ‘hese beds have been
much misunderstood. I shall postpone their consideration for the
present and will now limit myself to the other class, namely, the
Tapes beds, which occur here associated with a much richer fauna
than they do in the southern part of the Cattegat. The greater
richness in forms of these more northern beds must not allow us,
however, to disguise the fact that they are otherwise quite continuous
with the Zapes beds further south, and are earmarked by the
presence of the same critical species.

In regard to the mollusca found in these Zapes beds of the northern
Cattegat, a long list has been given by Erdmann, who says they do
not occur there at a higher level than 100 to 150 feet, and are for
the most part of littoral species. They are found in deposits of the
so-called black clay (svartlera), in raised beaches and sometimes
capping some of the @sar as in Eastern Sweden, but contain a much
richer number of species and were clearly deposited under conditions
of greater saltness in the water than those further south.

Erdmann, in his account of the Quaternary deposits of Sweden,
gives the following list of the shells found in the black clays :—

GASTEROPODA.

Litorina litorea.

L. rudis.

L. littoralis.

Trochus cinerarius.

T. tunidus.

Natica nitida.

N. Montagu.

N. clausa.

N. Groenlandica.

NV. pulchella.

N. borealis.
Emarginula reticulata.
Lacuna vineta.

L. pallidula.
Turritella communis.
Cerithuum reticulatum.
C. adversum.
Odostomia rissoides.
Purpura lapillus.
Nassa reticulata.

N. incrassata.

N. pygmea.
Aporrhais pes-pelicant.
Buccinum undatum.
Fusus undatus.

F’. despectus.

Trophon clathratus,var. minor.

Mangelia linearis.
Rissoa ebriata.

R. labiosa.

R. ulve.

A. parva.

R. wstrea.

R. arctica.

Patella vulgata.
Acme@a virginea.
Lepeta cocca.
Pallidum rubellum.
Dentalium (Antalis) entale.
Puncturella Noacina.
Peliscus commodys.
Philine quadrata.
Tornatella tornatilis.
Cylichna cylindracea.
C. truncata.

LAMELLIBRANCHIA.

Mytilus edulis.
Mya truncata.
Modiola modiolus.
Solen ensis.
Cyprina islandica.
Nucula nucleus.
Leda pernula.

DL. caudata.
Cardium edule.

C. echinatum.

C. fasciatum.

C. Norvegicum.
Lucina borealis.
Montacuta bidentata.
Isocardia cor.
Pecten islandicus.
P. maximus.

P. septemradiatus.
P. striatus.

P. pusio.

404 Sir H. H. Howorth—Geological History of the Baltic.

Pecten varius.
Sawicava rugosa:
S. arctica.
Tellina proxima.
T. solidula.

T. fibula.
Syndosmya alba.
S. intermedia.
S. mtida.
Astarte arctica.
A. elliptica.

Cochlodesma pretenue.
Tapes pullastra.

Venus striatula.

V. ovata.
Scrobicularia piperata.
Ostrea edulis.

Anomia patellaformis.
A. aculeatum.

A. ephippium. -

Rhynchonella psittacea.

A. sulcata.

A. compressa. Echinus droebackiensis.
Thracia villosiuscula.

Mactra subtruncata. Balanus porcatus.

M. elliptica. B. crenatus.

See GEOL. MaG., 1897, pp. 355, 361; 1898, pp. 195, 257; 1905,
pp. 407, 454. :

Others who have devoted some time to the exploration of the later
geology of Western Sweden have described the shell beds on its
shores, which point the same moral as those of Denmark, namely,
their occurrence at a gradualiy increased elevation as we proceed
northwards. In Southern Bohuslan Olbers found the shell beds at
a height of 15 metres. At Stromstad De Geer found them at a height
of 40 metres, while at Bullaresjon, on the Norwegian frontier,
Olbers again records having found them at 48 metres high (Nathorst,
Sverige Geol., p. 275). (See Olbers, Bidrag till Goteborgs och Bohuslans
geologt, Stockholm, 1870; see also on Halland, G.F.F., 1875.)

Olbers separates the deposits into two series: one of them he calls
Cardium lera, characterized by Cardium edule and C. echinatum,
Cyprina islandica, and Turritella communis, while the other, which he
calls Ostrea lera, and which he considers to be the younger, is
marked by the presence of Ostrea edulis, with Patella, Cerithium,
Rissoa, etc. There are, however, local variations, due not to
difference of age, but of the level at which they lived, and the
differing habitat.

North of Bohuslan we reach the Gotha, a famous river, the gateway
of a very interesting portion of Sweden, and specially noteworthy in
view of the issues we are discussing. In an earlier page we had
a good deal to say of the collapse that occurred in the lowest part of
the synclinal depressions through which the Forchhammer line runs.
We have now reached the part of Sweden through which another
line and focus of movement runs, namely, the highest part of the
anticlinal, and therefore also a district in which the tension must
have been extreme and the likelihood of great dislocation very great.
The Gotha River, in fact, leads us into a part of Sweden where the
proofs of this are written on all sides. The Gotha itself now flows
through the most tremendous gorges in Europe, the famous
Trollhatten falls, which must have been caused by great breakages.
They have all the appearance of being very recent and do not
represent in any way the original drainage channel of the river.
One fact suggesting a catastrophic cause for them is notable. The
salmon which inhabit the great lakes which the Gotha drains must

Sur H. H. Howorth—Geological History of the Baltic. 405

once have had access to the sea at certain seasons, as is the case with
these fish elsewhere. It is now imprisoned in the lakes all the year
round. ‘his is no doubt due to the cutting off of its waterway
thither by the dislocations I have mentioned, which are thus proved
to have been sudden and paroxysmal. The gorge is closely associated
with the numerous raised beaches in the district, both on the coast
and inland, and which are at an abnormal height. There is no other
explanation of the presence of the raised shell beds here, but the
bodily and violent uplifting of the rocks on which they lie to the
height of several hundreds of feet. This is shown by a remarkable
and well-known fact.

When Lyell examined the surface of the gneiss at Capellbacken
immediately above the shell beds he found barnacles (Balan)
adhering to it, showing the sea had remained there a long time
and then been suddenly uplifted, for the barnacles (Balanz) do not
occur at lower levels here. Lyell says he was able to verify this
observation by finding in the summer of 1834 at Kured, about two
miles north of Uddevalla and about 100 feet above the sea, a surface
of gneiss newly laid open by the removal of a mass of shells used
largely for making lime, etc., with the barnacles (Balani) so firmly
adhering to the gneiss that he was able to break off pieces of the
latter with the shells attached. The face of the gneiss was also
covered with Bryozoa. Other beds with the same shells occur near
Uddevalla, others again on the opposite island of Orust, as well as in
that at ‘I’jorn and at points on the coast still further sonth (Principles
of Geology, ii, 192).

While this is the evidence-of the barnacles (Balan) in regard to
the uplift of the rocks themselves, the evidence of the shells in the
raised beaches is also most impressive. I have spent a considerable
time among them on the spot and I have never seen anything like
them. The number of different species coming from several zones of
very different depths is phenomenal. Gwyn Jeffreys collected eighty-
three species. ‘They occur here in immense masses which have been
largely quarried, not mixed with sand and clay, but for the most
part washed clean; quite different, therefore, from any deposits in
the beaches to be found on ordinary shores.

They are also very perfect and quite unweathered. I havea large
collection of them, exceedingly few of which are broken, and there
are a great many very fragile and tender shells such as big specimens
of Pholas, with their internal hooks quite intact, among them.
Attempts have been made to sort them out into different zones by
Gwyn Jeffreys, but they have signally failed, as Brogger allows.
If they were the current “deposits of different periods they would not
le as they do in juxtaposition. The only solution of their condition
and position is that they were collected by some great tidal wave
from a sea bottom of varying depth. These shells are also of the
most recent types, and except one or two insignificant varieties all
are living in the adjoining seas. ‘lo my own eye nothing | have
seen of the kind presents more complete evidence of the solid: arity of
the beds in regard to the time and method of deposit. May I add
that the fact of the Balani remaining attached to the polished

406 Sir H. H. H oworth—CGeological History of the Baltic.

rocks, and as fresh under their covering of shells as if recently dead,
and showing no signs of weathering, absolutely proves to me that
they were not exposed to the weather during a gentle or long-
enduring elevation, but were lifted up suddenly by one impulse
with the rocks to which they are attached and at once covered by
the protecting shell beds to the height of 200 feet above sea-level
or more. They attest most completely the cataclysm which
must have occurred when the great Swedish anticlinal was lifted
bodily up.

Several of the great Scandinavian rivers, says NReclus, have
changed their courses. There wasa time when the River Foenmund,
now draining southward to the Cattegat through the River Klar,
drained through the Dalelf south-east to the Gulf of Bothnia. The
old bed of the river is still visible four or five feet above the present
lake. The Gotha was recompensed by receiving from another source
all the waters of the Glommen, so that its volume was more than
doubled.

The extent of country, too, where the shells have been found at
high levels in Central Sweden is very great; they have been found in
Jemteland, West Gothland, and Dalsland, while on the heights
commanding the Lakes Wener, Wettern, and Mjosen, and the Malar
Sea great beds of oysters occur, showing how much of the high land
there has been submerged. These great lakes have clearly been
lately united and formed a great gulf which was in fact an extension
of the Cattegat. This was clearly seen and stated long ago by Lyell.

In his Bakerian Lecture, printed in the Philosophical Transactions
for 1835, Lyell said it is evident from the position of the fossil
shells of several species on the coast of the Baltic between Gefle and
Sodertelje, and on the shores of the ocean between Uddevalla and
Gothenburg, that the tract of land which once separated the two
seas in this region was much narrower at a comparatively modern
period. Shells like those at Uddevalla have not only been found
a few miles due east of that place, but as far inland as Trollhatten,
in digging the canal there, and still further in the interior, about
fifty miles from the coast at Tuscdalersbacken and other places near
Rogvarpen in Dalsland on the west side of Lake Wener. Of these
matters an account is given by Hisinger (Anteckningen, iv, 42).
They are found in Dalsland as far above the sea as near Uddevalla,
or about 200 feet high, so that when deposited we must suppose the
whole of Lake Wener, the surface of which lies at an inferior level, to
have formed part of the ocean.

Another evidence of the extent of dislocation will be referred to
presently when we discuss the so-called Yoldia sea and the distribu-
tion of that much misunderstood and very important shell in the
district we are considering, where it has been found at great heights
and yet must have lived at very great depths.

The contours and great depths of the Swedish lakes and their
abnormal living contents also go to show that quite recently
geologically they have been united and that they have been subject
to disruptive movements. Although their surface is above the level
of the sea the beds of most of them are much below that of the Baltic

Sir H. H. Howorth—Geological History of the Baltic. 407

Wener has a mean elevation of 144 feet, while its extreme depth is
290 feet; Wettern is twice the altitude of Wener and is also deeper,
measuring 417 feet in depth and being 126 feet below that of the
adjoining sea. The Mjosen Lake, which is 197 square miles in
extent, has an extreme depth of 1,480 feet with an altitude of 397.

The curious fish and crustaceans contained in these lakes have
been accepted as relics of former conditions when they formed part
of the gulf already mentioned and when it was occupied by salt
water, and they have since adapted themselves to freshwater con-
ditions. The Norwegian lake of Mjésen, although it is so fardistant
from Lakes Wener and Wettern, also contains one of these relics in
the form of DMysis relicta.

The evidence therefore abounds that in that part of Sweden
where the upheaval has been the greatest there are the most potent
proofs that it culminated in great changes of the earth’s crust on
a mighty scale at a very recent period. This must, it is clear, be
taken into account as a postulate when we are analysing the later
geological history of the country. It seems to me also that sub-
sidiary evidence of these fractures and breaks is to be found.in the
utterly smashed condition of the Silurian beds in the upper parts of
the Baltic region, the broken and angular debris of which have been so
widely scattered, and also the existence of so many beds of quite sharp-
edged unaltered stones, the equivalents of the angular drift of the
English southern coast lands, which it would seem impossible to
account for except as the result of enormous impacts caused by
spasmodic movements.

Let us now proceed further north. We have reached the frontier
separating Sweden and Norway. The political frontier- position
corresponds to no definite physical one. There is complete
continuity in the geology across the political ‘‘divide”’ so far as it
relates to the latest period. The raised beaches are clearly con-
temporary in the coast-lands of Bohuslan and Central Sweden and
those of the great inland bight or gulf formed by the Skagerack on
the west and the Cattezat on the east, with the projecting pocket
known as the Christiania Fjord. In both cases we have two
definitely separated sets of raised beaches, one containing only a
highly Arctic fauna and existing for the most part at a low level and
the other characterized by the same fauna as still lives in the bight
and for the most part at high levels. The details of the phenomena
have been set out in an excellent and portly volume by Dr. Brogger
on The Raised Beaches of the Christiania Hyord, to which I am greatly
indebted.

Before dealing with these details, however, I propose to say a few
words in regard to the more general question in which Norway as
a whole has the same story to tell as Sweden.

The first point in which they agree is that both contain the
strongest evidence that the land has been quiescent for many
centuries. In a notable paper by Hansen, the latest authority on
the subject in Norway, he first calls attention to the divergent
opinions of older inquirers in both countries on the matter, and points
out the uncertainty in obtaining fixed elements to enable the problem

408 Sir H. H. Howorth—Geological History of the Baltic.

to be definitely solved, namely, the variation of the barometric
pressure, the height of the Atlantic tide, and the potency of the wind.
_ These make it difficult to fix any norm or index by which to
measure permanent changes of level, and he turns his inquiries from
the physical data to archeological evidence as affording a more
satisfactory result inasmuch as it enables us to cover a much longer
period of observation.

From the close of the Bronze or beginning of the early Iron Age,
we have cairns very near the present beach, and from the later Iron
Age we have also other fixed relics along the coast, which are now
quite as near the sea-level as it is possible for them to be. From
these it must be concluded, says our author, ‘‘that the sea-level has
not been subjected to any permanent secular change on the
Norwegian coast in the last millennium, very likely not in the last
two thousand years”’ (op. cit., p.110). Some critical examples may
be quoted in support of this generalization: Everest, in his travels
in Norway, informs us that the Island of Munkolm, an insulated
rock in the harbour of Trondhjem, proves that the land there has not
altered in level for eight centuries. The island is not larger than
a small village. By an official survey the highest point is only
23 feet above river high-water mark, and a monastery was founded
there by Canute the First in a.p. 1028, and thirty-eight years before -
that it was used as.a place for execution (Lyell, Principles, 1i,.
p. 195, 1875).

In regard to the rate of the rise, Hansen again says: ‘‘ The
present shore-line in Norway is of considerable age. It is impossible
to believe that the present clearly defined, strongly developed beach
extending from high to low water has been formed under any
(however slow) secular shifting of the sea-level. The rocks
immediately above show in some places the work of the breakers,
which cannot be observed higher up, and the surface-profile in loose
material does not answer at all to a regular rise of the land”
(ibid., pp. 110-11). It is plain, therefore, that the raised beaches
of Norway, as of Sweden and Britain, point to the jand having been
long quiescent, while they index a period when the earth was
subjected to great movements, which nevertheless were contemporary
with the present marine fauna in the North Sea. These movements
virtually ceased hundreds of years ago. In Norway, as in Sweden,
therefore, we have the same kind of evidence that the uplift has not
been continuous but spasmodic, which is again revealed by insulated
raised beaches separated by stretches void of such testimony. They
occur at different levels in different places, but as far as we know
synchronous. The culminating point of the raised beaches with
shells on the west of Norway is in the Trondhjem Fjord, where they
reach to a height of 600 feet. There, as in Sweden, they descend in
level both as we travel northward and southward. Von Buch, in the
Breistad Fjord, some distance north of Trondhjem, found marine
shells 140 feet above the sea-level (Reisen, pp. 1-251). M. Eugene
Robert describes how, in the Island of Ham between North Cape and
Hammerfest, he had found a great alluvial deposit running with
a gentle slope to a height of more than 101:7 feet, and showing

F, W. Harmer—Position of the Coralline Crag. 409

seven stages or terraces faintly marked, formed of marine pebbles
placed one behind another and separated by turfy soil. The whole
of this system, he says, rests upon a thick layer of the debris of
shells, among which we perceive fragments of Cyprina islandica and
other molluses, identical with those now living in the Polar ocean.
It is the same with regard to the Island of Qualse, and we have
there an additional curious point, namely, his discovery in a depression
behind the gate of the town of Hammerfest, and at a height of about
82 feet above the sea a number of erratics, the interstices between
which are filled with small pieces of blackish pumice-stone, similar
to those which continue to be thrown ashore from time to time, even
in the present day, on the coast of Norway, along with floating
wood, whose origin is evidently to be assigned to the volcanic
eruptions of Iceland, or of that of Jan Mayen (Chambers, Sea
Margins, pp. 286-7).

Bravais (‘‘ Former Sea-level in Finmark”: Q.J.G.S., i, p. 544,
1845) points out how in Finmark the shell beds occur at a much
lower level than further south. At Talvig, by digging about half
_ a metre below the surface in a sheltered part df the bay, he laid
open a clayey bank containing Mya truncata and Tellina Balthica,
some of the specimens being remarkably fresh and even showing
vestiges of the epidermis. This bed was 7 metres only above the
sea-level and appeared identical with one described by M. Keilhau.
‘7 have likewise,” he says, ‘‘received other shells (Patella and
Venus) collected near Storvig, at the western extremity of the Island
of Sorde, in a sandy deposit a few metres above the level of the sea.
The elevation in this case was about 30 metres.”

A similar drop in the shelly beaches has been noticed in pro-
ceeding southwards from Trondhjem, showing that the movement of
the land in Western Norway (as in Sweden) has been differential,
with a culminating point at Trondhjem. ~

(To be concluded in our next Number.)

TV.—Tue SrratigrRaPHicaL Posirion oF THE CoraLLINE Crag.
By F..W. HAaRMER, F.R. Met. Soc., F.G.S.

N an interesting paper lately published’ my friend Mae Be
Newton has expressed the opinion that the Coralline Crag
should be grouped with the Diestien and Anversien of Belgium as
Upper Miocene, the fauna of the Suffolk boxstones being regarded by
him as Middle Mageene. The recent researches of Mr. Miteed Bell?
have led me to agree with Mr. Newton that the latter is pre-Pliocene,
but I regret I cannot accept his view as to the age of the Coralline
Crag, which I consider to be more nearly related to the Waltonian
horizon of the Red Crag than to the Belgian Miocene.
In the introduction to my Memoir on the Pliocene Mollusca of
Great Britain, now in course of publication (pt. i, p. 5), I proposed

1 Journ. of Conch., vol. xv, p. 115, 1915.
2 GEOL. MAG., Dec. VI, Vol. IV, 1 AO AALS WOMENS 195 LG), JA UO.
Figs. 3, 4, 1918.

410 F. W. Harmer—Position of the Coralline Crag.

the following classification of the various divisions of the Anglo-
Belgian deposits, to which, with the exception of the point alluded
to above, I still adhere: —

Uprer PLIocENeE.

Belgium and Holland. England.
Amstelien. Butleyan and Newbournian.
Poederlien Wenleoek ( Walton horizon.

Scaldisien a aaa { Oakley horizon.
Casterlien (zone a Jsocardia cor). Coralline Crag.

Lower Prrocene.
Diestien (zone a Terebratula grandis). Lenham Bed.

In his synoptical list of 18741 Wood reported 430 species of
Mollusca as known to him from the Coralline Crag; of these only
about 90 had been found at that time at Walton, but even then
he had come to the conclusion that there was a close connexion
between the two deposits and that his original reference of the
former to the Miocene had been a mistake.

The investigations of Professor Kendall and the late R. G. Bell at
Walton and my own at Little Oakley have strongly supported
Wood’s later opinion. Of the 430 Coralline Crag species referred to,
about 270 are now known from the Waltonian or some later horizon,
while hardly any of the remainder can be considered common or
representative Coralline Crag forms. To regard a species of which
only one or at the most a very few specimens have been obtained
during ‘the labours of a century as of equivalent value, for purposes
of analysis, to others of which a large number could be found at any
time in a few days, is misleading. It is by the general facies of
a fauna—by the abundant and not by the rare examples—that we
should be guided.

While, therefore, nearly all the characteristic Coralline Crag
species continued to exist in the Anglo-Belgian basin during
Waltonian times, or even to a later period, no such correspondence
can be traced between its fauna and that of the Belgian Miocene,
zones & Panopea Menardi and Pectunculus pilosus of Van den Broeck
(Anversien, Newton). Out of 230 species of mollusca reported
from the latter horizon by the former observer, only 106 are known
from the Coralline Crag, the rest being generally and distinctly of an
older type.”

The true Belgian equivalent of the Coralline Crag is the zone a
Isocardia cor, the fauna of the two being practically identical. Of
about 150 species given by M. Van der Broeck? or M. Bernays * from
the latter (for which I have revived the name of Casterlien), all but
about half a dozen have been obtained from the Coralline or the
Waltonian Crags. The Casterlien, moreover, bears a relation to the

' Mon. Crag Moll., 1st Suppl., pt. ii, p. 203, 1874.

2 Ann. Soc. malac. Belg., vol. ix, pp. 118, 134, 1874.

3 Op. cit., p. 187; Bull. Soc. Belge Géol., vol. vi (Mém., pp. 120, 130,
1892).

* Bull. Soc. Belge Géol., vol. x (Mém., p. 128, 1896).

F. W. Harmer—Position of the Coralline Orag. 411

Scaldisien of Belgium similar to that between the Coralline and
Waltonian Crags. A reference to lists of fossils from all these
beds shows that the connexion between the Coralline—Casterlien and
the Waltonian—Scaldisien deposits is as clearly marked as is the
difference between the former group and the Anversien (Miocene) of
Belgium.

In a well-known work the late Mr. C. Reid identified the Lower
Red Crag with the Astian and the Coralline with the Plaisancian of
Piedmont, placing the one in the Upper, the other in the Lower
Pliocene.’ In the light of our present knowledge I cannot see any
sufficient reason for such a division of these East Anglian beds, all of
which I continue to regard as Upper Pliocene. The introduction to
the Anglo-Belgian basin of some northern mollusca during the
Waltonian period while many southern and Coralline Crag species
continued to linger on was due, I think, to the tectonic movement
described in one of my former papers, by which the Crag sea was .
brought then and for the first time under the influence of marine
currents from the north.’

I agree with Mr. Newton that the Lenham fauna is older than
that of the Coralline Crag, though I don’t think that anyone who
has a working knowledge of the subject could regard the list of
Lenham fossils given by him or the specimens on his plates as a typical
collection of Coralline Crag fossils. I hesitate, however, to regard
them as Miocene. Stratigraphically they are connected with the
sands of Louvain and Diest (zone of Zerebratula grandis) by a remark-
able series of isolated remnants of that deposit (as shown on the
annexed-map, copied from one of M. Rutot’s), which form a curved
line, extending roughly from west to east, through Folkestone,
Calais, Cassell, Tournai, Grammont, and Brussels.

ANTWERP

Leniiarg,

o

‘olkestone
Cala; Oe
BRUSSELS, Louvain
(3)
22)
as Grammont
Tournar

Sketch-map showing the connexion between the Lenham Bed and the Diestien
sands of Louvain and Diest (after Rutot).

The Diestien sands have been always regarded as Pliocene by
Belgian geologists. Until now I have never heard it suggested that
they are Miocene, but if the stratigraphical evidence is of any value
and the Diestien beds are Pliocene, the Lenham Bed must be Pliocene
also, though Lower and not Upper Pliocene as is, I submit, the
Coralline — Casterlien group. They contain some characteristic
Miocene or Lower Pliocene species unknown from the Coralline
Crag, but they contain also a considerable proportion of a more recent

Pliocene Deposits of Great Britain, 1890, pt. i, p. 5.
“ Quart. Journ. Geol. Soc., vol. lii, p. 761, fig. iv, 1896.

412 Herbert A. Baker—Denudation of the Chalk.

character which it seems to me would be out of place in a typical
Miocene deposit.

Leaving on one side the northern species which appear to have
been more or less suddenly introduced into the Crag basin under the
influence of the tectonic depression alluded to, and counting
specimens rather than species, there is a general resemblance
between the fauna of the Coralline Crag and that of Walton which
does not exist between those of the former and of Lenham. For
zoological as well as for stratigraphical reasons J draw the line
separating the Lower and the Upper Pliocene divisions of the East
Anglian deposits between the Coralline Crag and the Lenham beds
rather than between the former and the Waltonian.

I agree to some extent with Mr. Newton as to the age of the block
of fossiliferous limestone described by him in 1917.1 From a very
superficial examination I formed a strong impression that it was
-pre-Pliocene, but I cannot admit, on the other hand, that it has
anything to do with the Coralline Crag. It reminded me of some
fossiliferous blocks which some years ago Mr. Van Watenschoot van
der Gracht informed me were occasionally dredged in the North Sea.
He seemed at that time to be under the impression that they were of
Oligocene age.? I believe a collection of fossils had been made from
them which « were then at The Hague. Hereafter it may be possible
to compare these Dutch specimens with those identified by
Mr. Newton. It seems not unlikely, moreover, that the latter may
be of a similar character to those found by Mr. "Norregaard in some
erratic boulders of Middle Miocene age obtained from a glacial clay
near Esbjerg,® but this could be probably ascertained without much
difficulty.

Although I do not agree with the classification adopted by
Mr. Newton, I welcome his recent papers as calling attention to an
important series of deposits in which formerly much interest was
taken, but of late years have been almost entirely neglected.

V.—On Svccussive Stages IN THE DENUDATION OF THE CHALK IN
East ANGLIA.

By HERBERT ARTHUR BAKER, B.Sc., F.G.S.

Nee ve attempt by the writer‘ to utilize the information at
aE present available with a view to gaining some notion of the
dominant characteristics of the denudation suffered by the Chalk of
the London Basin prior to the deposition of the Eocenes yielded
results of sufficient interest to encourage him to apply the same
method of analysis to the East Anglian area.

Sufficient data for the construction of a provisional map showing
the isopachyte system of the Chalk of this area lie to our hand,

1 Quart. Journ. Geol. Soc., vol. lxxii, p. 7, 1917.

2 T understand that there is some difference of opinion among Continental
geologists as to the correct division between the Oligocene and Miocene of
Northern Europe.

3 Danm. Geol. Undersdgelse [4], No. 5, p. 58, pls. i-iii, 1916.

4 Baker, GEou. MaG., July, 1918, pp. 296-305.

in Hast Anglia. 413:

although, so far as the writer is aware, there is as yet no map giving
direct information concerning the variation in thickness of the
formation.

We are in possession of a certain amount of information, from
deep wells and borings, concerning the level of the base of the Chalk
at various points throughout the area. While wishing that this
information were more abundant we need not be deterred from
proceeding with the investigation. Committing our data to paper
and considering the items of information correlatively, we find that
the base of the Chalk appears to slope away in a general east-north-
easterly direction with remarkable uniformity, dropping at the rate
of about 24 feet to the mile, throughout the whole of the eastern
portion of the area. Further west the contours take on a slight
sinuosity, assume a more or less north and south direction, and
become somewhat more closely spaced, indicating an increase in the
gradient. Since in the construction of this map we are able to use
the information supplied by only about half a dozen levels, it follows
that in our use of it we must not expect a greater degree of accuracy
than it is capable of yielding. But our confidence in the utility of
the map for the purpose which follows is maintained when we
observe that it so happens that the available levels are well
distributed, and further, that the contours over a great part of the
area are practically straight lines.

Haying represented cartographically our information concerning
the level of the base of the Chalk, we next require a similar
representation of our knowledge of the present level of its surface,
and this we find to our hand. The Chalk-surface contours of this
area have been mapped by Professor P. G. H. Boswell,’ and we are
able to avail ourselves of the results of his labours. If the base of
the Chalk were ‘‘ corrected’ in such a way as to cause it to occupy
a horizontal plane at sea-level, and the Chalk surface were modified
correspondingly, then lines joining points at which the surface of
the Chalk is at the same height above the base of the formation
would constitute the isopachyte system which we seek. We therefore
superimpose the Chalk-surface map upon that showing the level of
the base of the formation. At points where the contours intersect,
the amount of correction necessary to bring the base of the Chalk to
sea-level is indicated by the one map, and the appropriate correction
is applied to the other. The completed series of lines thus obtained
constitutes our provisional idea of the variations in thickness of the
Chalk in Kast Anglia, and is shown in the map here presented. The
sources of error are manifold, but every incorporated item of
additional information will bring the-final result nearer to the
truth—and however inaccurate the present map, it at least provides
us with a notion of the general character of the isopachyté system of
the East Anghan Chalk which we could never have conjured up had
the attempt not been made—and, further, by its aid certain salient
characteristics of the denudation undergone by this Chalk area jump
at once before the eye.

1 Boswell, Q.J.G.S., vol. Ixxi, pl. 1.

— 414 Herbert A. Baker—Denudation of the Chalk

In our study of the map it is helpful to bear one consideration in
mind. It is a fair assumption to make that, at the beginning of
Eocene times and again at the beginning of Pliocene times, the base
of the Chalk in this area did not deviate markedly from horizontality.
Consequently the lines upon our map give, for the area where the
Chalk is yet covered by Eocene, a generalized representation of the
pre-Eocene contours of the Chalk surface, and for the area where
the Chalk is covered by Crag, the pre-Pliocene contours. For that

Miles Meas Gis Oras i aaa
i — o— Boundary o Eocene

~ —— + — Boundary of Crag
Bt Zonal boundaries}

emnitella \ \ ucronata

IS IK

LOWER & MIDDLE CHALK

Map showing Chalk surface contours in the East Anglian area, when the base
of the Chalk is corrected to horizontality at sea-level. The lines also
serve as the isopachytes of the Chalk.

area where the Chalk is bare the lines serve to indicate the stage to
which its denudation has proceeded at the present day.

With regard to the pre-Kocene Chalk-surface contours, the most
outstanding features are that there appears to be a drop from the
figure of 1,350 feet at Happisburgh down to 1,000 feet at Aldeburgh,
and the prevailing direction of the lines is N.E.-S.W. There can be
very Itttle doubt but that we have here the last remaining evidence

wm East Anglia. 415

of the escarpment which in pre-Thanetian times faced south-east-
ward and stretched away many miles to the west and south. Between
Yarmouth and Aldeburgh there appears to be evidence of a drop to
the eastward, which is most clearly shown between Beccles and
Lowestoft, but we are hardly in a position to place much confidence
in any explanation put forward concerning this interesting and
somewhat unexpected feature. The writer thinks it not unlikely
that, along a N.W.-S.E. line traversing the central part of the
Norfolk area, there was, during the deposition of the Chalk, a definite
movement of depression, whereby a greater thickness of sediment
was deposited vertically above this line than was laid down farther
east. If this was the case, the severity of the denudation suffered
by the Chalk in, the central portion of the area is still further
emphasized.

The evidence of an advancement in the stage to which the
denudation of the Chalk proceeded during post-Eocene and pre-
Pliocene (i.e. Miocene) times, is very striking. The earth-move-
ments which were in operation in Miocene times, governing the
general character of the denudation, were, in this area, different in
their direction from those whose activity resulted in the production
of the old E.N.E.-W.S.W. pre-Eocene escarpment. A movement of
uplift along an axis traversing the central part of Norfolk, and
disposed in a general N.W.-S.E. direction, appears to have taken
place, and denudation proceeded in such a way as to produce an
escarpment facing west and making a pronounced feature in the
landscape. A strong valley was eroded in the Chalk in pre-Pliocene
times, but we are not in a position to state the age of the abrading
stream with any precision. It may have been initiated in pre-Kocene
times and perhaps entered the area at a spot somewhere between
Happisburgh and Yarmouth. On the supervention of the new
movement of uplift fresh river-systems were initiated, which are
those of the present day, and one stream, the Waveney, throughout
a part of its course, actually occupies the site of the old valley, thus
providing us with an interesting illustration of reversal of drainage.
The severity of this post-Eocene and pre-Pliocene denudation of the
Chalk is well brought out by the map. Where the isopachytes
emerge from beneath the Hocene cover they change direction most
abruptly and exhibit a very pronounced tendency towards parallelism
in a general N.W.-S.E. direction. A considerable thickness of chalk
must have been removed from the exposed portions of the formation
during this time, particularly in the northern part of the area.
With the advent of Crag times a further portion of the chalk surface
was covered, and that part which is yet concealed beneath the Crag
has, of course, escaped all post-Pliocene denudation. This post-
Pliocene denudation has effected the removal of much of the Crag
cover and carried the attrition of the chalk beneath it to a still more
advanced stage.

In addition to bringing out the interesting points already
considered, our map is of service in enabling us to insert the
boundaries of the outcrops of the successive zones of the Chalk,
for unless the zones vary in thickness throughout the area, the

416, Reviews—The.Palceeontographical Society.

outcrops of the successive boundaries will be in parallelism with
the lines on the map. ‘To take the case of the small area where
the Chalk surface is composed of the Ostrea lunata zone, Professor
Boswell has estimated! the maximum thickness of this zone before
it is overlain by Eocene deposits to be between 70 and 80 feet. ©
Consequently, on our map, the boundary between this zone and that
of Belemnitella mucronata will occupy a position between the 1,250
and 1,300 lines. Similarly, adopting Professor Boswell’s estimate of
240 feet as the thickness of the B. mucronata zone at the point
where the Eocene comes on, this will bring the position of its lower
boundary on our map between the 1,000 ‘and 1,050 lines. In the
same way, assuming the estimated thickness of about 135 feet for
the Actinocamax quadratus zone, its lower boundary will coincide
roughly with our 900 line; that of the MJarsupites zone, if its
thickness is between 60 and 70 feet, as Professor Boswell estimates,
will occur somewhat to the east of our 800 line; and that of the
Micraster coranguinum zone, if its thickness is 210 feet, will occur
a little to the east of our 600 line. The insertion of these zonal
boundary-lines on the map brings out well the unconformities
between the Kocene and Chalk and Pliocene and Chalk respectively,
but particularly that of the former, since the Eocene is seen
transgressing from Ostrea lunata Chalk in the north, across
B. mucronata Chalk, on to A. guadratus Chalk in the south.

Immediately to the south of the area under present discussion there
occurs a notable disturbance of the Chalk, but the consideration of
this feature lies outside the scope of the present brief paper.

REV LTEws.

oor me
J.—TuHe ParaonroGRaAPHICAL Socrery.

fF\HIS Society has just issued, for 1916, its Senemuen volume
(dated February, 1918), containine :—

1. Tue Weatprn anp Porseck Fisues. Part II. By
Dr. A. 8S. Woopwarp, F.R.S. pp. 49, with 10 plates. and
14 text-figures.

2. Tus Prrocere Mozzvsca. Part III. By F. W. Harmer,
F.G.8., ete. pp. 159, with 12 plates.

3. Tae Patmozorc Asrerozoa. Part III. By W. K. Sprenczr,
M.A., F.G.S. pp. 5Y, with 8 plates and 48 text-figures.

4, Brirish Grapronites. Part XI. By Miss Exues, Sce.D.,
and Miss Woop (Mrs. SHaxssprar), D.Sc. Edited by Professor
Larwortn, LL.D., F.R.S. pp. 60, with title-page and index.

The volume before us, literally produced ‘amidst war’s alarms”
~ (for the premises of Messrs. Adlard & Son, the printers, were upon
one occasion bombed by an enemy aeroplane), displays neither in the
quantity of its contributions nor their quality in authorship, illustra-
tions, printed matter, or paper any deterioration as compared with

1 Boswell, ‘‘ Notes on the Chalk of Suffolk’’: Journ. Ipswich and District
Field Club, vol. iv, pp. 17-26, 1913.

Reviews — The Paleontographical Socrety. 417

the long series of seventy volumes with which it now takes an
honourable place. Nor has the modest annual subscription of
one guinea been increased, notwithstanding the advanced price in
printing paper and illustrations and labour prevailing since the War.

In his monograph on the Wealden and Purbeck Fishes (part i1)
Dr. Arthur Smith Woodward gives an admirable series (pl. xi) of
the remarkable rows of small enamelled round, crushing, palatal
teeth in Lepidotus Mantella (one of the most characteristic of
Wealden fishes), showing the mammaliform apices and successional
teeth in sockets; also the large flank bony-enamelled scales (square
or rhomboidal in form), fixed in place and pegged down by. bony
processes like the slates upon a house-roof (described in parti, 1915).
The genus J/fesodon of Middle Purbeck age from Swanage, etc., with
its allied genera Homesodon (Lias and Portlandian), Mvcrodon(Purbeck),
aud Celodus (Lower Cretaceous and Purbeck), introduces us to
a singularly interesting series of Pyenodont fishes with flattened
sides more or less covered by enamelled rhomboidal scales with
small protruding, often beak-like, mouths and crushing teeth well
adapted to feed upon coral-zoophytes, crustacea, and molluscs.
This group of Mesozoic fishes is remarkably well preserved in the
lithographic rocks of Solenhofen, the Purbeck of England, and down
to the Lias, and without imaginary evolution the author is able to
give us on p. 49 an actual picture of Mesodon macropterus, as seen in
life, correct in every anatomical detail. There are numerous other
valuable text-figures, as well as ten plates drawn by Gertrude M.
Woodward, which add much to the interest of this important
monograph.

The third instalment of Mr. Harmer’s fine monograph of Pliocene
Mollusca maintains the high standard of the earlier parts, both in
the careful preparation of the author’s text and the very excellent
quality of the collotype plates executed by Mr. J.Green. Mr. Harmer
has been at infinite pains to trace the past history of each species
with its geological and geographical distribution and the collections
in which specimens are preserved, and in case of survivals their
present habitats. Many forms also are now figured and described
which occur in widely varied British and foreign localities, far
beyond Kast Anglia, which region gave birth to the parent
Crag monograph by S. V. Wood half a century or more ago.

In Mr. W. K. Spencer’s monograph on the Paleozoic Asterozoa
much attention is given by the author to the anatomical details of
structure upon which their zoological arrangement depends; indeed,
the external forms as shown in six out of the eight plates would
hardly suffice without the explanatory structural figures given in the
forty-eight text-illustrations and the anatomical details so carefully
delineated on pls. vii and vili (some of those on the plates being
perhaps needlessly large for the purpose of study, e.g. fig. 2, pl. vil,
and figs. 1, 2,and 7 on pl. viii). On the other hand, such a beautiful
form as Lepidaster Grayt (fig. 1, pl. vii) might well have been more
enlarged to show its details to advantage.

We congratulate the Misses Elles and Wood (Mrs. Shakespear)
and Professor Lapworth on the completion of their elaborate

DECADE VI.—VOL. V.—NO. IX. 27

418 Reviews—Mineral Resources of Great Britain.

monograph on British Graptolites. Part i was commenced in 1901,
and now by the issue of part xi, containing title-page and index and
23 pages of ‘‘ Historical Research”’, their labour, extending over
fifteen years, is happily completed. We heartily rejoice with
the threefold authors in the consummation of their most difficult.
task. Of the usefulness of such a great work we prophesy future
generations of students of paleontology will arise to bless the authors,
and also to support the Society as subscribers. Many too, we trust,
will likewise be found to add some good work to further the object of
the founders of the Society, namely, ‘‘to figure and describe every
species of British fossil.”

If.—Memorrs or THE GroLogicaL SuRVEY.

SpectaL Reports oN tHE MinERaL Resources or Great Brirarn.
Vol. VI: Refractory Materials: Ganister and Silica-Rock—Sand
for open-hearth Steel Furnaces—Dolomite—Resources and
Geology. pp. vi-+ 233, with three maps. London: T. Fisher
Unwin. 1918. Price 7s. 6d. net..

le this, the sixth volume of the reports on the mineral resources of
Great Britain, we have the first part of what promises to be

a comprehensive account of refractory materials. ‘The greater part.

of the memoir is occupied by the descriptions of the raw materials.

used in silica-brick manufacture. These comprise various rock-
types, including quartzite, siliceous sandstone, ‘‘ Dinas rock,’’

““oanister,’’ ‘‘ crowstone,” etc., and in a somewhat similar fashion

the manufactured materials are classified as silica-, ganister-, and

Dinas-bricks. Unfortunately, such words as ‘‘ganister’’? and

‘‘crowstone’’ are miners’ terms, and, owing to their use being local,

their exact significance is not well defined. The word ‘‘ ganister ”’

originally applied to the silica-rock on a particular horizon in the

Lower Coal-measures of the Sheffield district, has never been

satisfactorily defined, and it is doubtful whether the definition given

in the memoir settles the question.

It is impossible to use as the main criterion the geological horizon,
as not only does the rock vary in different areas but rocks practically
indistinguishable from it are found on other horizons in other
localities. The rock must be defined in terms of its petrographical
characteristics, but in order that such definition be generally
adopted, it must contain references to those properties which
determine the utility of the rock as raw material for silica-bricks..
The Geological Survey definition is practically a petrographical
description of the typical Sheffield rock, but little attempt is made
to take into account the latter consideration. There is no doubt.
that the chemical composition, size and shape of the quartz-grains
and the amount and nature of the impurities are of great importance
so far as the refractory properties are concerned, but the distribution
of these impurities and the nature of the thin layers between the
grains must also be considered, owing to their probable action as
accelerators of the inversion of the quartz to the high temperature
forms, cristobalite and tridymite. Owing to the great expansion

Reviews—Mineral Resources of Great Britain. 419

during these inversions, the best rock, other things being equal, is
that in which as much of the quartz as possible can be transformed
during manufacture and which therefore will show the smailest
after-expansion in use. It is improbable that a really satisfactory
definition will be obtained until more is known concerning the
petrological properties which determine the usability of the rock.

In the introductory chapter an account of the manufacture of
silica-bricks is given, and this, considering its condensed nature,
is satisfactory except with regard to the temperatures to which the
bricks are fired. It is stated, for example, that in North Wales
these range from cone 16 to cone 29, but these figures are much
higher than those attained in general practice. It is very doubtful
whether first-grade silica-bricks are ever fired in this country at
temperatures above cone 16, and this can be verified by a comparison
of British and American bricks. The latter are rarely fired above
cone 17 or 18, and, even taking into account the more prolonged
firing, the much smaller proportion of unconverted quartz which
they contain, in comparison with the former, can only be explained
by the lower temperature to which the British bricks have been
subjected during firing.

The major portion of the memoir is taken up by an account, with
details of the occurrence, methods of working, reserves, etc., of the
mines and quarries in ‘which siliceous rocks are obtained, short
petrographical descriptions of the rocks being appended. The
qualitative nature of the latter militates against the utility of the
results. It is greatly to be regretted that practically no chemical
details are given and also that the refractory tests mentioned in the
preface as having been carried out are deferred, apparently to a later .
volume. ‘These data would have been much more useful if they had
appeared with the descriptive part. The latter seems to be fairly
accurate and detailed so far as the materials already being worked
are concerned, but the information regarding untouched English
sources is very meagre, though there is a chapter on ‘‘ potential”
Scottish supplies.

In a chapter devoted to an account of the sand and clay pockets
of the Peak District, the geological age of the deposits is given as
possibly ‘‘ post-Triassic and pre-Glacial’’, while in a table earlier in
the volume they are characterized as ‘‘ post-Glacial”’.. As a matter
of fact, the post-Triassic age of some of these deposits cannot be
regarded as definitely proved.

‘The remainder of the volume describes the British deposits of
sand suitable for open-hearth steel furnaces, and of dolomite for
lining converters, the beds of open-hearth furnaces, etc. In con-
nexion with the paragraph on the decalcification of dolomite, some
recent work on the Grenville (Quebec) deposits may be noticed.
Where the material is a mixture of magnesite and dolomite, it is
possible to increase the proportion of magnesia by ‘‘slaking” the
calcined minerals, but it has not been found possible to vary the
proportions of lime and magnesia by this method in dolomite alone.

The editing of the collected information has, as usual, been well
done, though a few misprints occur: for example, the spelling

420 Reviews—Coal Area, British Columbia,

“ Keeleshall’’ should refer to the Staffordshire place of that name,
the Sheffield place being usually ‘‘Ecclesall’’. Even when the
increased costs. of publication are considered, the price seems
somewhat higher than necessary.

ee

I1I.—Grotoey or a Porrron or THE FLATHEAD Coat AREA, Bririso
Corumsra. By J. D. Macxenzin. Geological Survey of Canada,
Memoir 87, 1916. pp. ii + 58, with 1 plate and 2 maps.

fJ\HIS coalfield lies on the western side of the Flathead Walleye

a little over 2 miles north of the 49th parallel, and 35 miles
by road from Corbin Station, on the C.P.R., the nearest railway
station in Canada, ‘The Flathead Valley runs ‘north and south, and
is a rift faulted in between the Clarke and Macdonald ranges of the

Rocky Mountains. The coal area, which is about 43 miles long by

33 miles wide, is let down into the western side of the valley by two

parallel normal faults striking N.W.-S.E.

This district includes rocks from Devono-Carboniferous to Upper
Cretaceous, all of which lie on one another in apparent conformity,
a few Eocene lacustrine deposits and moraines and glacial drift.

The coal-bearing formation is the Kootenay, of Lower Cretaceous
age. This consists of about 1,100 feet of grey and brown sandstones
and shales, which contain 80 feet of coal. The productive measures
are all situated in the lower 400 feet of the series and contain five
seams which are respectively 4, 7, 8, 25, and 36 feet thick. From
the included fossils and the character and distribution of the rocks it
is inferred that the Kootenay Series was laid down in a string of
lakes or swamps along the main axis of the Rocky Mountain Chain.
The coal is bituminous and soft, but on the whole of good quality,
though the full thickness of the seams is not workable in all cases.
The mines are still in the prospecting stage, but the conditions and
quality are such that mining will be profitable as soon as railway
transport is provided. In addition to the coal some thin lignite
seams occur in the Tertiary beds, but these are not of any value.
Also globules of bitumen have been noticed in the finer-grained
calcareous beds of the Tertiary formation, which are supposed to
indicate the presence of petroleum. Some prospecting has been
carried out in these rocks, but no oil has yet been found.

We Eeewe

ITV.—Reports on cerrain MrNeRAts USED IN THE ARTS AND INDUSTRIES:
Grapuitr. By P. A. Wagener. South African Journal of
Industries, February, 1918.

(JVHIS paper contains a good account of the properties and uses of

graphite, with a detailed description of the South African
sources of supply. Although these are not very large, they are at
present supplying a considerable part of the local demand. The
only locality actually being exploited is situated in the eastern
portion of the Zoutpansbere district of the Transvaal. Here the
mineral occurs as a lens lying between pyroxenite and quartzite.

Samples assayed from 50 to 90 per cent of carbon, and several

Reviews—<Asbestos. | 421

different grades are now on the market. Several other occurrences
are known in the Transvaal and Natal, but they do not seem to be of
much commercial importance.

V.—Assestos. By P. A. Waener. South African Journal of
Industries, November, 1917.
‘OUR principal varieties of asbestos are recognized, namely,
chrysotile-asbestos, tremolite-asbestos, crocidotile-asbestos, and
iron-amphibole. All of these occur in South Africa, the first in
Rhodesia, the second in Zululand, the third in Griqualand West,
and the last in the Transvaal. The reserves of chrysotile-asbestos in
Rhodesia and of crocidolite in Griqualand West are enormous, and
there seems to be every prospect of an important and flourishing
industry in the near future, likely to compete with Canada as the
world’s greatest producer.

Vi.—Tur Zones oF tHE Karroo System AND THEIR DIsTRIBUTION.
By eae ie Due Lom Procs (Geolt) Socs South) Airica:) 1918;
pp. Xvll-xxxvi, with a map.

OR the subject of his presidential address to the Geological
Society of South Africa Dr. du Toit chose the general characters

and distribution of the rocks of the Karroo System. Sufficient work
has now been accomplished to allow of a discussion of the correlation
of the subdivisions of the system in different parts of the Union.

An important conclusion has been reached in the establishment of

a stratigraphical break between the Dwyka and Ecca Series,

beginning~ somewhere between East London and Pondoland and

increasing in importance towards the north-east; this accounts for
certain anomalies seen in Natal and the Transvaal, where there is no
equivalent of the Upper Dwyka shales of the Cape Province.

Paleontological study now tends to show that the Dwyka Series is

of Upper Carboniferous age, while the Ecca and Lower Beaufort

Beds are Permian, the Upper Beaufort, Molteno, and Red Beds are

Trias, while the uppermost volcanics may possibly be Rhetic. The

author is to be congratulated on an excellent summary of a large

subject.
Tiseelalg dts

RHPORTS AND PROCHEHDINGS.-
———~<__—-

Gronocisrs’ AssocraTION.

1. June 7, 1918.—J. F. N. Green, B.A., F.G.S., President, in the
Chair.

The following paper was read :—

“The Skiddaw Granite: a Structural Study.” By J. Frederick
N. Green, B.A., F.G.S.

The problem of the age of the Skiddaw Granite can only be
attacked by structural methods. The distribution of cleav age in the
aureole points to pressure later than the intrusion. The Mosedale
fault, which brings unaltered parts of the Carrick Fell complex
against garnet-cordierite-hornfelses of the inner aureole, is of the

492 Correspondence—H. A. Baker.

type connected with the Devonian movements, and gives no
indication of entering the Carboniferous. Microscopic examination
of contact-altered rock suggests that the cleavage is later than the
recrystallization. Thus the granite is older than the chief move-
ments (Devonian). It is associated with an anticline demonstrably
pre-Bala, running oblique to the Devonian folding, and is therefore
probably itself pre-Bala and of the same age as the surrounding
intrusions which belong to the Borrowdale suite.

The following lecture was delivered :-—

‘“« Diagrams illustrating the Significance of Rock Analyses.” By
John William Evans, D.Sc., LL.B., F.G-.S.

The diagrams are of two kinds: (1) Individual rock diagrams
intended to indicate at a glance the significance of the analyses of
a rock or complex mineral silicate; (2) Linear rock diagrams. The
different types of linear or variation diagrams, in which the chemical
constituents of different rocks are represented by vertical distances,
were reviewed and a new type proposed in which each rock is
represented by two diagrams: (a) alumina diagram, (6) silica
diagram.

In describing these diagrams, the lecturer discussed various
problems connected with the genesis and composition of igneous
rocks.

2. July 5, 1918.—J. F. N. Green, B.A., F.G.S., President, in the
Chair.

The following lecture was delivered :—

‘A Visit to Christmas Island and the Cocos-Keeling Islands.”
By C. W. Andrews, D.Sc., F.R.S., F.G.S.

The structure and physical geography of Christmas Island (Indian
Ocean), a raised coral island, was described and compared with
those of the Cocos-Keeling Islands, a typical atoll. Some account
of the fauna and flora of Christmas Island was given, with special
reference to the means of colonization of oceanic islands.

The lecture was illustrated by lantern slides.

CORREBSPON DANCE.

THE PRE-THANETIAN EROSION OF THE CHALK.

Sir,—I should like to express to Mr. C. N. Bromehead my
erateful thanks for his criticism of my paper on the Pre-Thanetian
Erosion of the Chalk of the London Basin. I am afraid I must
plead guilty to the charge of not having made use of all the evidence
available, in ignorance as I was of the appearance of the Geological
Survey Memoir on Zhe Geology of Windsor and Chertsey. This
memoir has, I suppose, been published since the outbreak of war
and I have been continuously on active service, first flying in
France and later serving afloat, since 1915. In any geological work
with which I endeavour to beguile the tedium of life afloat I am
greatly handicapped by being unable to make references to authorities,
or even to consult earlier work of my own. The paper under present
discussion was simply the outcome of an attempt on my part to apply
cartographic methods to the data in my possession bearing upon the

Correspondence—H. A. Baker. 423

question at issue. The results seemed to me interesting and worthy
of print. Yet while being the first to admit the scantiness of my
data, I cannot bring myself to agree with a policy which refrains
from any kind of cartographical expression until ample data have
accumulated. Comparative treatment and correlation of items of
information in ways such as I have adopted, as well as being the
strictly scientific method of procedure, is that which puts each item
to its maximum of utility. I am convinced that field-geologists
would often save themselves much haphazard wandering if they
made greater use of cartographical methods beforehand. It is true
that very limited data produce very generalized results, but the
method works out its own salvation in the long run, and the results
then achieved are unattainable in any other way. It is very faint
praise to say that ‘‘ when the amount of evidence available is larger,
the method may be of some value’. Had I been in the more
fortunate position of Mr. Bromehead, I should long ago have given
cartographical expression to my data. The result would have been
«a map full of imperfections, and doubtless in places at variance with
field observations. Yet the steady incorporation of each fresh item
of information would bring that map nearer and nearer to perfection
and more and more in agreement with field observations.

Much as [ should like to, I am unable, at the moment of writing,
to discuss in any detail with Mr. Bromehead the other points which
he raises. He remarks that ‘‘it seems natural to ascertain as far as
possible the zone of the Chalk immediately underlying the Tertiary
at the boundary of the latter, and to check the zones whose presence
beneath -the Tertiary is deduced from borings by these facts”.
I take it, then, that if Mr. Bromehead observed the Marsupites zone
(say) immediately underlying the Tertiary at the boundary of the
latter, he would naturally expect to find the same zone beneath the
Tertiary cover. This seems to me a wilful ignoring of the teachings
of tectonics, and since we already know that a strong unconformity
exists between the Tertiaries and the Chalk, a most unsound view
to take.

With regard to the ‘‘series of gentle folds whose axes run about
E. 15°S.”, referred to by Mr. Bromehead, I spent considerable time in
1913 studying these as well as evidences of disturbances of quite
different relationship. A fact which made a profound impression
upon me was that whereas in the Isle of Wight the Upper Chalk is
1,200 feet thick, in Dorset 1,000 feet, in Berks 800 feet, and in
Norfolk 1,000 feet, yet in the London Basin, beneath the Tertiary
cover, it is often less (and in places considerably less) than 300 feet.
In view of this and many other facts, I concluded that while the
evidence of a system of approximately east and west folds, including
those referred to by Mr. Bromehead, was indisputable, yet this
folding did not take the place of premier importance in determining
the character of the denudation undergone by successive members of
the Mesozoics, including the Chalk. The interesting items of field
observation cited by Mr. Bromehead support his tentative suggestion
of a set of approximately east and west folds in the Beaconsfield—
Winkfield area, and it should be borne in mind that these

4.24, Correspondence—J. A. Bartrum.

undulations must affect the level of the base of the Chalk, and in
constructing my map showing levels in the base of the Chalk I was
without adequate data concerning these anomalous levels in this
particular area. With the incorporation of a sufficiency of data in
the maps the final result would agree with field observations—and
while the data accumulate a ay map is better than no map.

i HH. A. Baker.

AFLOAT,
H.M.S. ‘‘ CARYSFORT ’’.
July 25, 1918.

NOTES AND QUERIES FROM NEW ZEALAND.

Sir,—I am forwarding two photographs in which perchance some
of your readers may be interested. One represents the common
rhombohedral multiple twin of calcite, seen on a weathered surface
of the mineral, and the other an unknown fossil. [| We omit the
description of the photographs, which is appended to the figures given
below.—Ep. Grot. Mac.]

I have discarded all thought of inorganic origin for the “‘ fossil”
on account of the great regularity and the successive layers shown,
but can offer no convincing suggestion as to the actual nature, and
shall be grateful for any information thereon.

Joun A. Barrrum (Lecturer in Geology).

UNIVERSITY COLLEGE,

AUCKLAND, NEW ZEALAND.
May 6, 1918.

Having referred Mr. Bartrum’s photographs to our colleagues
Dr. G. F. H. Smith and Dr. F. A. Bather, of the British Museum
(Natural History), Cromwell Road, we have been favoured with the
following remarks thereon.—Ep. Grou. Mace.

Fie. 1: Cancrre Creavacr.—This shows clearly the crossing lamelle
seen on a weathered surface of a specimen of twinned calcite from
Port Waikato, New Zealand. The lamelle are usually rendered
conspicuous owing to readier solution along the composition planes,
but occasionally it appears as if there has been differential solution
‘of the opposed sets of twin-lamella.—G. F. H. S.

bo
Ot

—Correspondence—J. A. Bartrum. A

‘Fie. 2: Crustacean Tracks 1n New Zeatanp TeErrraRies.—
This photograph, of natural size, depicts a portion of a large slab of
soft sandstone recently exposed in strata of Middle Tertiary age
along Beach Road, Auckland, New Zealand. The surface is covered
with feather-like or fern-like markings which represent casts formed
in the tracks left by some creature. The track (not the cast) consists
of a median groove from which leaf-like imprints are given off on each
side. ‘The groove, which has a semicircular section, is about 5 mm.
wide and pursues a gently sinuous course. Each appendage is about
138mm. long, has a curved free margin, the curve having a radius of
about 19mm., and is overlapped by the corresponding margin of the
adjacent imprint at a distance varying in different appendages from
3°5to6mm. The greatest width in each case is at about two-thirds
the distance from the point of origin. The axis of each appendage
forms with the median axis of the whole imprint an angle varying
between 35° and 75°, the greater angle usually being on the convex
side of a sinuosity in the median track. It is hard to say whether
the appendages are opposite’or alternate.

Markings like those in Fig. 2 were formerly assigned to marine
algee (Chordophycee) or to annelids (Werertes), but the observations
of many naturalists, summarized and supplemented in Nathorst’s

426 Obituary—Dr. BE. A. Newell Arber.

classical memoir ‘‘Om spar af nagra evertebrerade djur, etc.” (1881,
_K. Svenska Vet. Akad. Handl., vol. xviii, No. 7), have shown that
they are almost certainly to be attributed to Crustacea. Such a
track as the present one was probably formed by a large crustacean:
swimming close to the sea-floor rather than crawling on a mud- flat.
It is of the same general character as Polykampton alpinum Ooster,
1869, from the Rheetic of Switzerland (‘‘ Protozoé Helvetica,”
vol. i, p. 23, pl. iv), and Delesserites foliatus R. Ludwig, 1869, from
the Upper ‘Devonian of Dillenburg (Palgontographica, vol. xvii,
p. 113, pl. xx, fig. 4).—F. A. B.

@OBtLDO AR Yi:

E. A. NEWELL ARBER,
MAS Seb GS. PinSuiie

Born AUGUST 5, 1870. DIED JUNE 14, 1918.
(WITH A PORTRAIT, PLATE XV.)

Epwarp Atrxanper NewreLtt ArsBer was born at No. 5 Queen
Square, Bloomsbury, in 1870. His father was Edward Arber,
afterwards Professor of English at Mason’s College, Birmingham,
and known as the editor of many English classics. His mother
(née Marion Murray), the daughter of a “Glasgow publisher, was the
niece of Dr. John Sutherland, an early authority on army sanitation,
who was closely associated with Florence Nightingale’s work in the
Crimea.

Newell Arber had much illness in early boyhood, and at the age of
fifteen he was sent, for the sake of his health, to Davos, where he
spent more than a year. It was during his first Swiss summer that
he awoke to the fascination of botany; his interest in geology was
aroused later, apparently at the beginning of his Cambridge career.
In 1895 he came up to Trinity College, and after an undergraduate
period broken by ill-health, he took ‘the two parts of the “Natural
Sciences Tripos in 1898 and 1899, specializing in Botany and Geology.

In 1899 Professor T. McKenny Hughes nominated Newell Arber
to a Demonstratorship in Paleobotany in the Woodwardian (after-
wards Sedgwick) Museum. This post, which he held for the rest of
his life, involved the curating of the paleobotanical collections, as
well as elementary and advanced lectures and demonstrations in
fossil botany. Newell Arber threw himself enthusiastically into
museum work, and during his tenure of the Demonstratorship about
5,000 plant fossils were added to the collections, almost entirely
through his instrumentality. Between 1901 and 1906 he was also
responsible—in the first year, under Dr. Henry Woodward, and after
that, under his successor, Dr. Arthur Smith Woodward—for the
naming and arrangement of the paleobotanical specimens in the
Geological Department of the British Museum (Nat. Hist.). He
consolidated his knowledge of fossil plants by repeated visits to most
of the principal museums in Europe in which important collections
are to be found.

Research flourished in Newell Arber’s laboratory, where, in

Grou. Maa., 1918. ; PEATE XY.

Elliott & Fry, Paoto. Bale, Sons and Danielsson, Ltd.

Be Che Sy aes

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Obituary—Dr, E. A. Newell Arber. 427

addition to some sixty of his own memoirs, about twenty-five
original papers were produced (either jointly or independently) by
a group of students including at different times Bernard Smith,
H. Hamshaw Thomas, L. J. Wills, W. T. Gordon, D. G. Lillie,
R. D. Vernon, A. W. R. Don, R. H. Goode, and others. In 1905
a moiety of the Lyell Fund was awarded to Newell Arber by the
Geological Society, and in 1914 he was elected an Honorary Member
of the New Zealand Institute in recognition of his work on
Australasian geology.

From the strictly geological standpoint, Newell Arber’s contribu-
tion to the science may perhaps be summarized as consisting chiefly
in the application of paleobotanical evidence to stratigraphical
problems. One of his early memoirs (1903) dealt with the use of
Carboniferous plants as zonal indices, a subject of which the founda-
tions for this country had been so firmly laid by Dr. Kidston.
Much of Newell Arber’s later work was concerned with further
developments on these lines, and he produced a series of papers
dealing with the fossil floras and geological structure of the English
coal-fields. His book on The Natural History of Coal was sub-
sequently translated into Russian. The economic bearing of his.
paleobotanical work resulted in a consulting practice concerning
the geology of coal both in this and other countries. Newell Arber
did not confine his attention, however, to the Paleozoic period, but
studied also the fossil floras of the Mesozoic rocks, especially those
of the southern hemisphere. In this connexion his British Museum
Catalogue of the Glossopterts Flora (1905) may be mentioned, and his
recent account of the earlier Mesozoic Floras of New Zealand (1917).
He continued his work to within less than three months of his death,
leaving memoirs, in various stages of completion, relating to general
paleobotany, and to Devonian, Carboniferous, and Mesozoic plants;
it is hoped that some of these may eventually be published.

Newell Arber had an exceptionally wide knowledge of geological
literature, which embraced even its obscurest corners. His interest
in bibliographical questions and his high standard of accuracy in
such matters, were somewhat unusual in a scientific man and were
probably due to his father’s influence. But he was no arm-chair
geologist. He laid great stress on the importance of taking his
research pupils into the open, where he initiated them into the
methods of outdoor work. He had that instinct for the field,
common to so many geologists, which on its material side results in
a complete grasp of topography, and on its romantic side may rise
to a capacity for being possessed by an absorbing passion for a tract
of country. Botanically, Switzerland was his Mecca, while in his
geological life Devonshire held a corresponding place. The desire
to get there was often almost painfully intense; to quote from one
of his letters—‘‘I have had a bad attack of the ‘ West [Devon]
a calling’ . It gets worse and is getting beyond my control.”
Newell ower made ‘twelve geological expeditions to North Devon,
mainly in connexion with his study of the Upper Carboniferous
rocks. The difficulties of the work were extreme. As he wrote
after the appearance in 1904 of his paper on the Culm Measures of

428 Obituary—Dr. E. A. Newell Arber.

this part of England—‘‘In the old days in the train I approached
Bideford with great sinkings of heart. The possibilities of failure
-were immense and the chances of success seemed ml. Altogether
I suppose it was the hardest nut I shall ever have to crack and
I marvel at my luck.” Later, as a by-product of this stratigraphical
study, he was drawn to an investigation of the physical geology of
North Devon, and in particular of the coastal waterfalls, eto
resulted in his book on the coast scenery of the region (1911).
In much of this work D. G. Lillie and Inkermann Rogers were
associated with him.

That deep-seated delight in field-work, Gach is in some ways the
ultimate joy of the geologist, is indicated by a passage from one of
Newell Arber’s letters, which may perhaps not unfitly conclude this
tentative outline of his geological life. ‘‘I thought I would take
a holiday for the rest of the evening and indulge in a fit of ‘ field-
fever’ or ‘field-dreams’. I wonder if you know what this is. Poor
old Robert Dick heard or felt ‘field-work’ calling many a time.
People who have been in the East, tell me they very often feel a great .
longing to return again. .’. . A perfect day when one is in the
field is one of the greatest things on earth. . My mania is quite
a modest one. It is a desire to visit every spot in this country where
fossil plants have ever been found. To gain that full power of know-
ledge which can only be got by having been to the place, seen it,
photographed it and collected from it. When you have done this
you have a ‘grip’ which is masterly.” rion

LIST OF THE MORE IMPORTANT GEOLOGICAL AND PALMOBOTANICAL BOOKS.
AND MEMOIRS BY EH. A. NEWELL ARBER. (A number of titles, including
all Dey botanical work, have been omitted for the sake of brevity. )

1901. ‘‘ Notes on Royle’s Types of Fossil Plants from India ’’: GEOL. Mag.,

Dec. IV, Vol. VIII, pp. 546-9.
1902. ‘‘ On the Clarke Collection of Fossil Plants from New South Wales’? :
Quart. Journ. Geol. Soc., vol. lviii, pp. 1-26, 1 pl., 1 text-fig.
‘“Notes on the Binney Collection of Coal-Measure Plants. Part IIT:
The Type Specimens of Lyginodendron Oldhamium (Binney) ”’ :
Proc. Camb. Phil. Soc., vol. xi, pp. 281-5, 2 text-figs.
1903. ‘‘The Fossil Flora of the Cumberland Coalfield, and the Paleobotanical
Kyvidence with regard to the Age of the Beds’’?: Quart. Journ.
Geol. Soc., vol. lix, pp. 1-22, 2 pls.
(Conjointly with A.C. SEWARD. ) **Les Nipadites des Couches Hoceénes
de la Belgique’’: Mém. du Musée royal d’hist. nat. de Belgique,
t. 2, 16 pp., 3 pls.
*“ Notes on some Fossil Plants collected by Mr. Molyneux in Rhodesia’’
Quart. Journ. Geol. Soc., vol. lix, pp. 288-90.

“On the Roots of Medullosa anglica’’?: Ann. Bot., vol. xvii,
pp. 425-33, 1 pl.
“The Use of Carboniferous Plants as Zonal Indices’’: Trans. Inst.

Min. Eng., pp. 371-89.

‘“On Homceomorphy among Fossil Plants’?: Grou. MaG., Dec. IV,
Vol. X, pp. 885-8.

‘‘Notes on Fossil Plants from the Ardwick Series of Manchester ”’ :
Mem. and Proc. Manchester Lit. and Phil. Soc., vol. xlviii, Man.
Mem., No. 2, 32 pp., 1 pl., 1 text-fig.

1904. ‘* Cupressinoxylon Hookert, sp. noy., a large Silicified Tree from

Tasmania’’?: GEOL. MaG., Dec. V, Vol. I, pp. 7-11, 1 pl.,
2 text-figs.

1904.

1905.

1906.

1907.

1908.

1909.

1910.

Obitwary—Dr. E, A. Newell Arber. 429

‘The Fossil Flora of the Culm Measures of North-west Devon, and
the Paleobotanical Evidence with Regard to the Age of the Beds’’:
Phil. Trans. Roy. Soc. Lond., ser. B, vol. exevii, pp. 291-325, 2 pls.

(Conjointly with I. RoGERS.) ‘‘ Note on a New Fossiliferous Limestone
in the Upper Culm Measures of West Devon’’: Guo. MAG.,
Dec. V, Vol. I, pp. 305-8.

““On some New Species of Lagenostoma, a Type of Pteridospermous
Seed from the Coal Measures’’: Proc. Roy. Soc., vol. lxxyviB,
pp. 245-59, 2 pls.

‘* On the Sporangium-like Organs of Glossopteris Browniana, Brongn.’ :
Quart. Journ. Geol. Soc., vol. lxi, pp. 324-38, 2 pls.

Catalogue of the Fossil Plants of the Glossopteris Flora in the
Department of Geology, British Musewm (Nat. Hist.). Being
a Monograph of the Permo-Carboniferous Flora of India and the
Southern Hemisphere. London, lxxiv + 255 pp., 8 pls., 1 map,
51 text-figs.

‘On the Past History of the Ferns’’: Ann. Bot., vol. xx, pp. 215-32,
1 text-fig.

- “* Bibliography of Literature on Paleozoic Fossil Plants, including some

of the more important memoirs published between 1870-1905.’’
Progressus Rei Botanice. Bd. i, pp. 218-42.

““The Origin of Gymnosperms’’: Science Progress, vol. i, No. 2,
pp- 222-37. -

“*On the Upper Carboniferous Rocks of West Devon and North
Cornwall’: Quart. Journ. Geol. Soc., vol. Ixiii, pp. 1-27,
3 text-figs.

““A Note on Fossil Plants from the Carboniferous Limestone of
Chepstow’’: GEOL. MAG., Dec. V, Vol. IV, pp. 4-5.

(Conjointly with JOHN PARKIN.) ‘‘On the Origin of Angiosperms ”’ :
Linn. Soc. Journ. Bot., vol. xxxviii, pp. 29-80, 4 text-figs.

_ (Translated into German as ‘‘ Der Ursprung der Angiospermen ’’ :
Osterreich. bot. Zeitschr. Jahreg., 1908, p. 89, etc.)

““On Triassic Species of the Genera Zamites and. Pterophyllum:
Types of Fronds belonging to the Cycadophyta’’: Trans. Linn.
Soc. Lond., ser. 11, Bot., vol. vii, pt. vii, pp. 109-27, 3 pls.

““On a New Pteridosperm possessing the Sphenopteris Type of
Foliage’’: Ann. Bot., vol. xxii, pp. 57-62, 1 pl.

(Conjointly with H. HamsHaw Tuomas.) ‘‘On the Structure of
Sigillaria scutellata, Brongn., and other Eusigillarian Stems, in
comparison with those of other Paleozoic Lycopods’’: Phil. Trans.
Roy. Soc. Lond., ser. B, vol. cc, pp. 133-66, 3 pls.

“On the Affinities of the Triassic Plant Yuccites vogesiacus, Schimper
and Mougeot’’: GEOL. MaG., Dec. V, Vol. VI, pp. 11-14.

‘© On the Fossil Plants of the Waldershare and Fredville Series of the
Kent Coalfield’’?: Quart. Journ. Geol. Soc., vol. lxv, pp. 21-39,
1 pl.

Fossil Plants. Gowans’s Nature Books, No. 21, 75 pp., 60 pls.
Glasgow. ;

(Conjointly with H. HAMsHAW THOMAS.) ‘‘ A Note on the Structure
of the Cortex of Sigillaria mammillaris, Brongn.’’: Ann. Bot.,
vol. xxiii, pp. 513-14.

**Note on a Collection of Fossil Plants from the Neighbourhood of
Lake Nyasa, collected by Mr. A. R. Andrew’’: Quart. Journ.
Geol. Soc., vol. lxvi, pp. 237-9.

““Notes on a Collection of Fossil Plants from the Newent Coal-field
(Gloucestershire) ’?: GEOL. MAG., Dec. V, Vol. VII, pp. 241-4.
‘A note on some Fossil Plants from Newfoundland’’: Proc. Camb.

Phil. Soc., vol. xv, pp. 390-2, 2 text-figs.

““ Some Fossil Plants from Western Australia,’’ III. Paleeont. Contri-
butions to the Geology of West. Aust.: Geol. Sury. Bull. 36,
pp. 25-8.

430

1910.

1911.

1912.

1913.

1914.

1915.

1916.

Obituary—Dr. E, A. Newell Arber,

‘* On the Fossil Flora of the Southern Portion of the Yorkshire Coal-
field in North Derbyshire and Nottinghamshire’’: Proc. Yorks.
Geol. Soc., vol. xvii, pt. ii, pp. 132-55, 8 pls.

‘“ A Note on a Fossil Wood from Intombi Camp, Ladysmith ’’?: Ann.
Natal Museum, vol. ii, p. 233. ;

The Natural History of Coal. x+163 pp., 21 text-figs. Cambridge
University Press. (Translated into Russian, 1914.)

The Coast Scenery of North Devon, being an account of the Geclngtaal
Features of the Coast-line extending from Porlock in Somerset to
Boscastle in North Cornwall. xxiv +261 pp., 70 pls., 12 text-figs.,
2maps. London: Dent.

“The Culm-measures of the Exeter District ’’: GroL. MAG., Dec. V,
Vol. VIII, pp. 495-7.

‘“The Lower Carboniferous (Carboniferous Limestone) Flora of the
Ballycastle Coalfield, Co. Antrim’’: Sci. Proe. Roy. Dublin Soc.,
vol. xiii, N.S., No. 12, pp. 162-76, 3 pls.

‘“The Fossil Flora of the Ingleton Coal-field (Yorkshire) ’?: GEOL.
MaG., Dec. V, Vol. IX, pp. 80-2.

‘“A Note on some Fossil Plants from the Kent Coal-field’’: ibid.,
pp. 97-9, 1 pl.

‘On the Fossil Flora of the Forest of Dean Coalfield (Gloucestershire),
and the Relationships of the Coalfields of the West of England and
South Wales’’: Phil. Trans. Roy. Soc. Lond., ser. B, vol. ccii,
pp. 233-81, 3 pls.

“On Psygmophyllum majus, sp. nov., from the Lower Carboniferous
Rocks of Newfoundland, together with a Revision of the Genus and
Remarks on its Affinities’’?: Trans. Linn. Soc. Lond., ser. 1, Bot.,.
vol. vii, pt. xviii, pp. 391-407, 3 pls., 1 text-fig.

‘“The Fossil Plants of the Forest of Dean Coalfield’’: Proc. Cotteswold
Nat. Field Club, vol. xvii, pt. iii, pp. 321-32, 4 pls.

‘*A Preliminary Note on the Fossil Plants of the Mount Potts Beds,
New Zealand, Collected by Mr. D. G. Lillie, Biologist to: Captain
Scott’s Antarctic Expedition in the Terra Nova’’: Proc. Roy. Soe.,
B, vol. Ixxxvi, pp. 344-7, 2 pls.

‘On the Discovery of Fossil Plants in the Old Hill Marls of the South
Staffordshire Coal-field’’: Grou. Mac., Dee. V, Vol. X,
pp. 215-16.

“On the Structure of Dadoxylon Kayi, sp. NOV. , from the Halesowen
Sandstone at Witley (Worcestershire) ’ : Quart. Journ. Geol. Soc.,
vol. lxix, pp. 454-7, 4 text-figs.

‘On the Fossil Floras of the Wyre Forest, with Special Reference to
the Geology of the Coalfield and its Relationships to the Neigh-
bouring Coal Measure Areas’’: Phil. Trans. Roy. Soc. Lond.,
ser. B, vol. cciv, pp. 363-445, 4 pls.

““ A Revision of the Seed Impressions of the British Coal Measures’? :
Ann. Bot., vol. xxviii, pp. 81-108, 3 pls., 8 text-figs.

‘“On the Fossil Flora of the Kent Coalfield’’: Quart. Journ. Geol.
Soc., vol. Ixx, pp. 54-81, 3 pls.

‘‘ Geology of the Kent Coalfield’? : Trans. Inst. Min. Eng., vol. xlvii,
pt. v, pp. 677-714.

(Conjointly with R. H. GoopE.) ‘‘On some Fossil Plants from the
Devonian Rocks of North Devon’’: Proc. Camb. Phil. Soce.,
vol. xviii, pp. 89-104, 1 pl., 3 text-figs.

““On a little-known concealed Coalfield in Oxfordshire’’: ibid.,
pp. 180-3. (See also Trans. Inst. Min. Eng., vol. 1, pt. ii,
pp. 373-84, 1916.)

““ Studies of the Geolog : The Coal-
measure records of four borings’’: Trans. Inst. Min. Eng., vol. 1,
pt. ii, pp. 351-72.

“* On the Fossil Floras of the Coal Measures of South Staffordshire ”’:
Phil. Trans. Roy. Soc. Lond., ser. B, vol. ccviii, pp. 127-55, 3 pls.,
3 text-figs.

Obituary—Prof. V. P. Amalitsky. 431

1916. ‘‘ The Structure of the South Staffordshire Coalfield, with special
reference to the concealed areas and to the neighbouring fields’? :
Trans. Inst. Min: Eng., vol. lii, pt. i, pp. 35-70.

1917. ‘‘ The Earlier Mesozoic Floras of New Zealand ’’: New Zealand Geol.
Surv., Paleontological Bulletin No. 6, 80 pp., 14 pls., 12 text-figs.
Wellington, N.Z.

1918. ‘* A Note on Submedullary Casts of Coal-measure Calamites ’’?: QOL.
Maa., Dec. VI, Vol. V, pp. 212-14.

VLADIMIR PROCHOROVITCH AMALITSKY.
Born 1860. DIED DECEMBER 28, 1917.
We regret to learn that Professor Amalitsky, of Warsaw,’ died
suddenly from heart failure last December at Kislovodsk, North
Caucasus. He was born in Volhynia in 1860, and received his
“scientific education at the University of Petrograd, where he was
especially attracted to geology by Professor Inostransev. He soon
became an accomplished student, and early in his career was
appointed Professor of Geology in the University of Warsaw. After-
wards he assumed the direction of the Polytechnic Institute in
‘Warsaw, and was occupied with his duties there at the outbreak of
war in 1914.

Professor Amalitsky devoted himself with great success to the
study of the Permian formations of Russia, and made a special effort
to discover remains of terrestrial and freshwater faunas and floras in
these rocks. He first met with unusually well-preserved freshwater
bivalved shells of the family Anthracosiide, which he described in
the Paleontographiea, vol. xxx1x (1892), and in the first part of
a Russian work intended to treat all aspects of Permian geology,
published in Warsaw, also in 1892. Three vears later he visited the
British Museum, with his equally accomplished wife, who always
shared his labours, and there he compared his Russian fossils with
the corresponding shells from the Karoo formation of South Africa.
The results of his researches were contributed to the Geological
Society of London in a paper entitled ‘‘A Comparison of the
Permian Freshwater Lamellibranchiata from Russia with those from
the Karoo System of South Africa’? (Quart. Journ. Geol. Soc.,
vol. li, pp. 837-51, pls. xii, xili, 1895).

While in London, Professor and Mrs. Amalitsky also studied the
Karoo reptiles and other Permian and Triassic fossils. ‘hey then
spent four seasons in exploring promising localities in the Permian
region of the northern Dwina, and discovered not only more fresh-
water shells but also the characteristic G@lossopteris Flora and great
deposits of concretions containing the skeletons of Reptiles and
Labyrinthodonts. In 1899 and 1900, with the aid of funds from
the Russian Ministry of Public Instruction, they made extensive
diggings in the beds of bone-bearing concretions and obtained a very
large collection which was sent to the University of Warsaw.
Skeletons of Pariasaurians proved to be especially abundant, and
there were numerous remains of Dicynodonts, Theriodonts, and
Deuterosaurians, besides well-preserved Labyrinthodonts. In
December, 1899, Professor Amalitsky made a general report on his
first year’s official work to the Imperial Society of Naturalists of
Petrograd, and published this as a separate pamphlet at Warsaw in

432 Obituary—Henry R. Knipe.

1900 (‘Sur les Fouilles de 1899 de Débris de Vertébrés dans les
Dépots Permiens de la Russie du Nord,” with 5 plates of photo-
graphs of the excavations). In 1901 he made a more precise com-
munication to the French Academy of Sciences (‘‘Sur la découverte,
dans les dépéots permiens supérieurs du nord de la Russie, d’une flore
glossoptérienne et de reptiles Pariasaurus et Dicynodon,’’? Comptes
Rendus, 4 Mars, 1901).

With much trouble Professor Amalitsky engaged and trained some
skilled masons to extricate his fossil skeletons from the intractable
matrix in which they were embedded, and more than one unfortu-
nately succumbed to the effect of the peculiar siliceous dust which
the work produced. At last, however, he secured a goodly series of ”
specimens ready for study, and when I saw the collection at Warsaw.
in 1908 he had already mounted six fine skeletons of Parzasaurus,
one of the Theriodont Jnostransevia, and a large number of important
pieces of Dicynodonts and Labyrinthodonts. Photographs of some
of these were published in Sir Ray Lankester’s Extinct Animals
(London, 1905), and plaster casts of a few characteristic specimens
were given by Professor Amalitsky to the British Museum in 1913.
Professor and Mrs. Amalitsky visited the British Museum several
times during the progress of their work, but unfortunately the new
duties at the Warsaw Polytechnic involved much distraction, and
when I last met the Professor in London in 1912 he told me he had
abandoned all hope of being able to describe the collection himself,
and proposed shortly to send one of his students to the British
Museum to make himself competent for the task. The War unfortu-
nately disarranged this plan, and it is sad to realize that Professor
Amalitsky will not now see the fruition of his labours.

Professor Amalitsky was a single-minded student beloved by all
who knew him, and while lamenting his premature loss to science,
his friends will tender their heartfelt sympathy to the amiable help-
mate who was his constant companion in research.

A. Suira Woopwarp.

HENRY ROBERT KINI RE) Rleso. 7 eGror

Born 1855. DIED JULY 26, 1918.
WE regret to record the death of Mr. Henry R. Knipe, who devoted
much time and labour to the popularization of the study of extinct
animals in this country. With the aid especially of the Staff of the
British Museum, and utilizing its collections and library, he
attempted to portray the animals of the past as they appeared when
living, and, sparing no expense, he employed the most skilled artists
to carry out his plans. Among those who produced his restorations
may be mentioned Mr. John Smit and Miss Alice B. Woodward.
His earliest efforts were published as a series of plates illustrating
a long poem named Webula to Man (London, 1905). More recently
a still finer series of restorations, chiefly by Miss Woodward, was
issued in his more systematic work in prose, Hvolution in the Past
(London, 1912). Apart from his scientific studies Mr. Knipe’s
interests were wide and varied, and by his death Tunbridge Wells
loses one of its most esteemed citizens and most generous
philanthropists.

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| (Gy Oy aN) Gish ON p Bre

Page | Il. Reviews. Page

The Imperial Mineral Resources | Summary of Progress, Geological
[BAUER DIE Sole SORE SBE BO Dano oe Bera aatos 433 Survey of Great Britain ......... 473
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I. ORIGINAL ARTICLES.
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GEOLOGICAL MAGAZINE:
NEW SERIES. DECADE VI. VOL. V.
No. X.— OCTOBER, 1918.

THE dmpertaL Minerat Resources Burnav.

T will be remembered that asa result of the deliberations of the
Imperial War Conference last year a Special Committee, under
the chairmanship of Sir James Stevenson, was appointed by
Dr. Addison, then Minister of Munitions, to prepare a scheme for
the establishment, in London, of an Imperial Mineral Resources
Bureau. ‘he proposal that the Committee was asked to examine
was, that a Bureau should be formed to collect information from
Government Departments and other sources in regard to the mineral
resources and metal requirements of the Empire, and that it should
advise what action, if any, might appear desirable to enable such
resources to be developed and made available.

The Committee reported at the end of July, 1917, and recommended
the formation of a Bureau with the following duties :—

1. To collect, co-ordinate, and disseminate information in regard
to the resources, production, treatment, consumption, and require-
ments of every mineral and metal of economic value.

2. To ascertain the scope of the existing agencies, with a view
ultimately to avoid any unnecessary overlapping that may prevail.

3. To devise means whereby the existing agencies may, if
necessary, be improved and assisted in the accomplishment of their
respective tasks.

4. To supplement those agencies, if necessary, in order to obtain
any information not now collected which may be required for the
Bureau.

5. To advise on the development of the mineral resources of the
Empire, or of particular parts of it, in order that such resources may
be made available for Imperial defence or industry.

After the consideration of the report the Government instructed
the Minister of Reconstruction, in consultation with the Secretaries
of State for the Colonies and India, to give effect to the findings of
the Committee. As these provided that the administration of the
Bureau was to be controlled by a governing body representing the
various parts of the Empire as well as the mineral and metal
industries, detailed proposals were submitted to the Dominion and
Indian Governments, who nominated their representatives; while
the remaining members of the governing body were nominated by
the Minister of Reconstruction in consultation with the Institution
of Mining and Metallurgy, the Institute of Metals, the Iron and
Steel Institute, and the Institute of Mining Engineers. This con-
stitution was ratified by the Imperial War Conference which met in
London this year.

The Bureau will be incorporated by Royal Charter, and the
governing body, which will be under the presidency of the Lord

DECADE VI.—VOL. V.—NO. X. 28

434 Dr, Wheelton Hind—British Carboniferous Gomiatites,

President of the Council, will have the following constitution :—
Chairman: Sir Richard Redmayne, representing the United King-
~ dom; and the following members: Dr. Willet G. Miller, representing
Canada; Mr. W. 8S. Robinson, Australia; Mr. T. Hutchinson
Hamer, New Zealand; The Rt. Hon. W. P. Schreiner, the
Union of South Africa; The Rt. Hon. Lord Morris, Newfoundland ;
Mr. R. D. Oldham, India; Dr. J. W. Evans, Crown Colonies;
Mr. W. Forster Brown (Mineral Advisor to HSM. Woods and
Forests); Professor H. C. H. Carpenter (President of the Institute
of Metals); Dr. F. H. Hatch (Member of the Mineral Resources
Advisory Committee of the Imperial Institute and Past President of
the Institution of Mining and Metallurgy); Sir Lionel Phillips
(late Director of the Mineral Resources Development Department,
Ministry of Munitions); Mr. Edgar Taylor (of John Taylor & Son,
and late President of the Institution of Mining and Metallurgy);
Mr. Wallace Thorneycroft (President of the Institution of Mining
Engineers). Mr. Arnold D. McNair is Secretary, and the offices of
the Bureau are for the present at the Holborn Viaduct Hotel, E.C.
Some department such as this has long been needed, and it is to
be hoped that the new body will fulfil ‘the expectations that have
been aroused by its appointment, and that its functions will not be
restricted to the collection and dissemination of information, but
that it will also institute such researches as may appear desirable as
to the occurrence of important but little-known minerals, both in

this country and in the Colonies. The exigences of the War have.

=shown how important for the welfare of the State the discovery of
new sources of such minerals may become; examples will occur to
everyone. In the present war the cutting off of overseas supplies
has necessitated the search for and development of home resources of
manganese, wolfram, iron pyrites, phosphates, petroleum, etc. ‘This
country has been well served in the past by its purely scientific
institutions, but the economic side has been unduly neglected. We
wish the Bureau a successful career in the important work assigned
to it.

ORIGINAL ARTICLES.

en

J.— On vue Disrripurion or tHE British CARBONIFEROUS
GoNIATITES, WITH A DESCRIPTION OF ONE NEw GENUS AND SOME
New SpOTTS.

By WHEELTON HIND, M.D., B.S., F.R.C.S., F.G.S.
(PLATE XVI.)

ART IIT of the Catalogue of the Fossil Cephalopoda in the British
Museum (Nat. Hist.), by A. H. Foord and G. C. Crick, was
published in 1897. Since then much fresh material has come into
my hands and it is now possible to give much more accurate and
fuller details of the horizons and localities at which the various
species oceur. ‘his is of special importance, in view of the fact that
the Goniatites can be used as zone indices of the Carboniferous Series
from the upper part of the Dibunophyllum beds (Dy of Dr. Vaughan)

‘

Dr, Wheelton Hind—British Carboniferous Goniatites, 435

up to the Middle Coal-measures. This I showed to be the case in
my Presidential address to the Yorkshire Naturalists’ Union, and
published in the Naturalist, April to July, 1909, and elsewhere.
Many details have, however, been added since then, and an elaborated
and emended table will be published in a forthcoming paper by
myself and Dr. Wilmore, F.G.S., on the Carboniferous succession of
some Midland areas.

The zones published in the Yorkshire Naturalist, op. supra cit.,
p. 154, were as follows:—

MILLSTONE GRITS ; p Gastrioceras listert.
PENDLESIDE SERIES . : Glyphioceras bilingue.
G. spirale.
G. reticulatum.
Posidonomya bechert.
Cyathaxonia.
CARBONIFEROUS LIMESTONE. Upper Dibunophyllum.

It may be briefly stated that the Goniatites mentioned above
occur with the utmost regularity wherever these horizons are
exposed. Of the zones in the above list the G. retzculatum zone is
the least satisfactory, on account of the persistence of the species from
Pendleside to Middle Coal-measure times. Several other Goniatite
zones will be indicated in the forthcoming paper, with greater detail
as to their extent. Many of the localities given in the Museum
Catalogue (op. supra cit.) are unsatisfactory, partly because, at the
time when it was published, the zones of the Carboniferous rocks
had not been made out, and partly because the real history of many
of the specimens in the Natural History Museum was not known.
Collections were largely referred to the town where the collectors
lived, e.g. Halifax, Todmorden. Halifax is given as a locality for
a large number of species which could not have come from the
Lower Coal-measures. I suspect that many of these, if not all,
came from the collection of the late J. W. Davis, of Halifax. I see
this fact was mentioned by Mr. Crick, Q.J.G.8., vol. 1xvii, pp. 400-4.
Long lists of fossils are given by J. W. Davis in his portion of the
volume, West Yorkshire, part i, Geology, 1878 (Davis and Lees),
but none are referred to Halifax as a locality. ‘The ‘‘ Hardbed Coal ”’
occurs there with the marine fossils of the Mountain Mine or
Bullion Coal, and the locality is correct for Gastrioceras listert,
G. carbonarium, Dimorphoceras gilbertsoni, D. looneyi, and D. discrepans.
The locality Halifax must therefore be called in question for all
Goniatites other than the above. ‘Todmorden is also unsatisfactory,
for, though the Goniatite beds occur at that town, the majority of
the collections have been made from Horsebridge Clough, Crimsworth
Dean, and High Green Wood, north of Hebden Bridge, from the
valley of Hebden Water and its tributary. The two former localities
are in the same little valley.

The Natural History Museum is fortunate in possessing nearly all
the types of Phillips’s Goniatites, but the localities given by him are
practically valueless. Bolland is a large district, partly in Lanca-
shire, partly in Yorkshire, and practically the whole of the Lower
Carboniferous rocks occur therein. Black Hall, near Chipping, and

436 Dr. Wheelton Hind—British Carboniferous Goniatites.

some of the Devonshire Culm localities are, however, sufficiently

detailed to determine the exact horizon. ‘‘ River Ribble”’ is, of course,
~ too vague. The Scottish localities are copied from the Handbook,
Brit. Assoc., Glasgow, 1901, p. 503, where there is a list of
Carboniferous Cephalopoda from the Clyde area, drawn up by
J. Neilson. Many Devonshire localities are quoted from Mr. Crick’s
paper, Q.J.G.S., vol. Ixvii, pp. 309-408.

Several Irish localities are quoted from Foord’s Carb. Ceph.,
Ireland, part v, Pal. Soc., vol. lvii, 1903. Several Irish specimens
which are known only from a single locality are not dealt with,
because I have no knowledge of the exact horizon at which they
occur. Unfortunately, it will be noted that all known British
Goniatites occur in the upper beds of the Carboniferous Limestone
and the succeeding series, and except in Ireland no Goniatites are
noted from beds below the Upper Dibunophyllum zone. I suspect
that Kniveton, however, will be eventually found to be of a much
lower horizon, and there I have obtained species which I refer to
G. corpulentum, M’Coy, and a variety of G. truncatum, and I possess
a large specimen of this variety from Clitheroe. The presence at
Kniveton of Pericyclus fasciculatus is interesting. De Koninck
has described the following species: From Tournai— Brancoceras
rotatorius, Glyphioceras complanaius, G. rotella, G. ryckholti,
G. crenulatus, G. perspectivus, G. belvalianus, Pericyclus divisus,
P. funatus (princeps). From Pauquys— Glyphioceras inconstans,
G. spheroidale, M’Coy, P. fasciculatus. From Veve—P. impressus.
At least four of the above species occur in Ireland.

TABLE OF DISTRIBUTION OF BRITISH GLYPHIOCERATIDA.

COAL-MEASURES . 2 . Glyphioceras reticulatum, Phillips.
G. micronotum, Phillips.
Dimorphoceras gilbertsoni, Phillips.
D. looneyi, Phillips.
Gastrioceras listert, Martin.
G. carbonarius, V. Buch.
G. coronatum, Foord & Crick.
Nomismoceras ornatun, Foord & Crick.

MILLSTONE GRIT s . Pericyclus impressus, de Koninck.
P. divaricatum, Hind.
Glyphioceras reticulatum, Phillips.

i. beyrichianwm, de Koninck.

. bilingue, Salter.

. calyx, Phillips.

. phillapsii, Foord & Crick.

. davisi, Foord & Crick.

. platylobum, Phillips.

. spirale (var.), Phillips.
Dimorphoceras gilbertsont, Phillips.
D. looneyi, Phillips.
D. discrepans, Brown.
Gastrioceras listeri, Martin.

PENDLESIDE SERIES . . Glyphioceras reticulatum, Phillips.
G. bilingue, Salter.
G. davisi, Foord & Crick.
G. phillipsti, Foord & Crick.
G. spirale, Phillips.

RRARARAR

Dr. Wheelton Hind—British Carboniferous Goniatites, 437

beyrichianum, de Koninck.

. striolatwm, Phillips.

bidorsale, Phillips.

calyx, Phillips.

vesica, Phillips.

mitidum, Phillips.

platylobum, Phillips. a
Dimorphoceras gibsont, Phillips.

D. looneyi, Phillips.

D. discrepans, Brown. Mh
Nomismoceras rotiforme, Phillips.
N. spirorbis, Phillips.

N. vittager, Phillips. zi
Prolecanites serpentinus, Phillips. es
P. compressus, Sowerby.

DADARAAN

CARBONIFEROUS LIMESTONE Pericyclus funatus, Sowerby. —
(Dz beds) P. fasciculatus, M’Coy.
P. doohylensis, Crick.
Brancoceras enniskillent, oord,
Glyphioceras crenistria, Phillips.
G. striatum, Sowerby.
G. sphericum, Martin.
. fimbriatum, Foord & Crick.
. obtusum, Phillips.
: implicatum, Phillips.
. truncatum, Phillips.
. nucronotum, Phillips.
. vesica, Phillips.
. mutabile, Phillips.
. excavatum, Phillips.
. vesiculifer, de Koninck.
. complicatum, de Koninck.
Nomismoceras vittager, Phillips (very rare).
Dimorphoceras gilbertsoni, Phillips.
Prolecanites cyclolobus, Phillips.
P. discoides, Foord & Crick.
P. mizxolobus, Phillips.
Pronorites cyclolobus, Phillips.

RADRARRVRRARR

Norrs on rach Sprecrms oF Carsonirerous GoNIATITES, WITH
‘Disrrisution anp Locatriries.
Genus Brancoceras.
BRANCOCERAS ENNISKILLENI, Foord. Dibunophyllum zone, Dg.
Derbyshire: Carsington.
Ireland: Blacklion, near Enniskillen.
Genus Pericyclus.
PericycLus Fascicutatus, M’Coy. ? Dibunophyllum zone, Dj.
Derbyshire: Kniveton.
Ireland: Little Island, co. Cork; Clane, co. Kildare.
Pericycrus Doonyiensis, Foord & Crick. Dibunophyllum zone, Dy.

Derbyshire: Kniveton.
Ireland: Doohyle, near Rathkeale, co. Limerick.

438 Dr. Wheelton Hind—British Carboniferous Goniatites.

Pericycius pivaricatus, Hind. Base of Pendleside Series to 3rd Grit.
Yorkshire: Cracoe Knolls, Flasby, Horsebridge Clough, near
Hebden Bridge.
Lancashire : River Ribble at Dinckley Hall, 3rd Grit Shales, Eecup.
Cheshire: In the G. spirale beds, Congleton Edge.
Isle of Man: P. bechert beds, Poolvash..

Genus Glyphioceras.

GLYPHIocERAS spHmericum, Phillips. Carboniferous Limestone,
upper beds of Upper Dibunophyitlum zone, Ds.

Lancashire: Black Hall. -

Yorkshire: Keal Hill, Craven.

Derbyshire: Crowdecote, Castleton, Chrome Hill.

Devon: Fremington, Bonhay Road, Exeter.

Isle of Man: Poolvash.

Scotland: Upper Limestone Series: Gare. Lower Limestone
Series: Corrieburn.

Ireland: Loughshinny, co. Dublin; Bantry, co. Cork.

GLYPHIOCERAS CRENISTRIA, Phillips. The upper beds of Upper
Dibunophyllum zone, Ds.

This is an important zone fossil. It occasionally passes up int
the Prolecanites zone just above it.

Lancashire: River Ribble at Dinckley Hall, Black Hall, and Cold
Coats, near Chipping.

Yorkshire: Keal Hill, Kl Bolton, Rilstone. The Knotts, Bolland
and Brockthornes, both 5 or 6 miles 8.E. of Long Preston. Salter-
- forth Railway Cutting.

Derbyshire: Castleton, Gluttondale, Chrome Hill.

Staffordshire: Wetton, Narrowdale.

Devonshire: Venn, Swimbridge, Bampton, and Bonhay Road,
Exeter; Burlescombe.

Isle of Man: Poolvash.

Ireland: Foord quotes Queen’s County and co. Fermanagh.

GLYPHIOCERAS FIMBRIATUM, Foord & Crick.

The validity of this species is doubtful, and its locality is not
recorded.
GLYPHIOCERAS sTRIATUM, Sowerby.

An important zone fossil which is common to the G. ecrenistria
and Prolecanites compressus beds, and also in the Posidonomya becherv
shales. Often crushed flat in shales, but easily recognized by its
spiral ornament.

Lancashire: River Ribble Dinckley Hall, Cold Coats.

Yorkshire: El Bolton, Keal Hill, Flasby, Eastby. Beck half-mile
N. of Ashnot inlier, Upper Hodder at D: ulehead, between Hammerton
Hall and Birch Hill.

Derbyshire : Chrome Hill.

Devonshire: Fremington.

Isle of Man: Poolvash.

North Wales: Teilia.

Dr, Wheelton Hind—British Carboniferous Goniatites., 439

Ireland: Courtlough, Garristown, and Newton, co. Dublin;
Drumscra, co. Tyrone.

Seotland: Upper Limestone Series: Gare. Lower Limestone
Series: shale above Hosie Limestone, Campsie. Main Limestone:
Carluke.

GLyPHIocERAS optusuM, Phillips. The G. crenistria beds.

Not at all a common species.

Lancashire: Black Hall, near Chipping.

Ireland: Co. Cork: Blackrock, Little Island, and Middleton.
Co. Waterford: Ballyduff. Co. Limerick: Ballynacarriga.

GLYPHIOCERAS PHILLIPSI, Foord & Crick. Base of Pendleside Series
to Milistone Grit.

Lancashire: River Ribble Dinckley Hall; Caton Green (Millstone
Grit). Butler’s Clough, Billington.

Yorkshire: Horsebridge Clough and Crimsworth Dean, Hebden
Bridge (G@. retvculatum zone); stream below Weets Head; stream
north-west of Ashnot, Rilstone.

Staffordshire : Waterhouses (G@. reteculatum beds).

Devonshire: Pinhoe Brickfield, Exeter.

North Wales: Holywell.

GLYPHIOCERAS MIcRonotuM, Phillips. Upper Dibunophyllum zone to
Middle Coal-measures.

Lancashire: River Ribble Dinckley Hall; Rough Lee (Sabden
Shales); River Hodder above the great falls.

Yorkshire: Rilstone and Lothersdale, 704 feet above Barnsley
Coal, Brodsworth.

Staffordshire: Narrowdale, Wetton; above the Gin Mine Coal, |
North Staffs Coalfield.

Derbyshire: Castleton, Park and Chrome Hills, Thorpe Cloud.

Isle of Man: Poolvash.

Scotland: Upper Limestone Series: Orchard and Garngad Road.
Lower Limestone Series: Shale over Hosie Limestone, Campsie, and
Thornton.

GLYPHIOCERAS TRUNCATUM, Phillips. Seminula -beds to Upper ©
Dibunophyllum.

Lancashire: River Ribble Dinckley Hall, Black Hall, Cold Coats;
?Salt Hill, Clitheroe (S. beds).

Yorkshire : Keal Hill and El Bolton.

Derbyshire: Chrome Hill, Park Hill, Castleton, Thorpe Cloud,
and Kniveton.

Staffordshire: Wetton, Narrowdale.

Isle of Man: Poolvash.

Scotland: Upper Limestone Series: Thornlebank.

Ireland: Drumscra, co. Tyrone; St. Donlaghs, co. Dublin; Clane,
co. Kildare; Little Island, Tankardstown, Middleton, co. Cork;
Lisnakeny, Nantenan, Ballyeahane, and Kilmacot, co. Limerick.

N.B.—The specimens quoted from Redesdale, Northumberland, in
the Catalogue probably belong to a new species of Pericyclus, but

440 Dr, Wheelton Hind—British Carboniferous Goniatites,

I have a specimen, a fragment of the body-chamber, which I think
should be referred to G. “truncatum.

GuyPHioceRas VESICA, Phillips. From the G. erenistria zone to the
G. spir ale zone, Ds, and Pendieside Series.
Lancashire: Black Hall, River Ribble W. of Dinckley Hall.
Yorkshire: Crimsworth Dean.
Scotland: Upper Limestone Series: Bowertrapping, Gare, Rob-
royston, Auchenbeg. Lower Limestone Series: Kast Kilbride,
Thornton.

GLyYPHIocERAS ImpLicatuM, Phillips. The G. crenistria zone, Do.

I have not met with this species in any of the collections from the
Hebden Bridge area that I have examined.

“Lancashire: Black Hall, River Ribble at Dinckley Hall.

Derbyshire: Chrome Hall,

Isle of Man: Poolvash.

Scotland: Upper Limestone Series: Gare, Robroyston.

GLYPHIOCERAS MUTABILE, Phillips. From the G. crenistria zone to
G. spirale zone.
Lancashire: River Ribble, W. of Dinckley Hall.
Yorkshire: Quarry 1 mile 8S. of Rilstone.
Derbyshire: Castleton, Storrs quarry, Bradbourne.
Staffordshire: Narrowdale.
Scotland: Upper Limestone Series: Gare, Robroyston.

GLYPHIOcERAS PLatyLoBum, Phillips. Pendleside Series to Millstone

Grit. .

Yorkshire: valley of the Nidd. Sabden Shales, Rough Lee;

Gillbeck, S8.E. of Lothersdale. Foord & Crick quote the species
from Wetton, Staffordshire, and Todmorden.

GLYPHIOCERAS stENoLopuM, Phillips.

This must be a rare or doubtful species. It must be noted that
the suture-lines figured by Phillips and by Foord & Crick are quite
different. Neither Phillips’s or their figures show that the shell
has a wide peripheral sinus as stated in the text. Unfortunately
the “type” has been lost, and the original locality, ‘‘ Bolland,”
gives no information as to the horizon whence the type-specimen
was obtained.

GuiyPHIoceRAs niTIpUM, Phillips. G. crenistria beds to Millstone
; Grit.
Lancashire: River Ribble Dinckley Hall, Black Hall, near

Chipping; Millstone Grit beds, stream N. of Haws House, 6 miles
E. of Lancaster.

GLYPHIOCERAS BILINGUE, Salter.

An important zone fossil. At Pendle Hill it characterizes 300 feet
of Black Shale below the Upper Pendle or Farey’s Grit. It occurs
in the Sabden Shales, W. of Sales Wheel, M.G.

Dr. Wheelton Hind—British Carboniferous Goniatites, 441.

Lancashire: Pendle Hill, Butlers Clough, Billington, and near
Lango; River Ribble E. of Sales Wheel, Longridge Fell; streams
N. of Chipping, Marsden Tunnel, Pule Hill.

Yorkshire: east bank of Winterburn Reservoir, stream half-mile
N.E. of Thorlby, shales S. of El Bolton, stream half-mile S., and
Clough, 1 mile 8. of Ashnot; Hareshaw, S. of Lothersdale, below
Weets Head and Kastby beck. Above Weston Grit, Clifton Bank,
1 mile N. of Otley. Millstone Grit Shales, Moreton Bank.

Derbyshire: River Dove, Glutton Bridge, Mam Tor, River Noe,
Bradwell and stream W. of Bradbourne.

Cheshire: River Dane half-mile E. of railway viaduct; Wild Moor,
Bank Hollow, E. of Macclesfield.

South Wales: Bishopton, near Swansea.

Ireland: Caher Lane and Rathcahill, near Abbeyfield, co. Limerick.

G:LYPHIOCERAS RETICULATUM, Phillips. Pendleside Series to Middle
Coal-measures.

An important species which when very young is strongly ribbed
and has a wide and deep umbilicus and a deep groove on the
periphery. As it grows the ornament becomes more delicately
reticulate and in the old stage the shell may be almost smooth.
Like G@. spirale and G. bilingue the aperture is curved at the sides
like a reversed S, and there is a deep sinus at the periphery. It is
quite open to doubt whether the horizon at Hebden Bridge may not
be Millstone Grit rather than Pendleside Series.

Lancashire: River Ribble W. of Dinckley Hall above . the
G. spirale beds, Pendle Hill above Hook Cliff; Sabden Shale,
Rough Lee.

Yorkshire: Holden Clough, Bolland; High Green Wood, Crims-
worth Dean, and Horsebridge Cough, Hebden Bridge; Millstone Grit
Shales at Eecup and Wadsworth Moor, 705 feet above Barnsley.
Coal, Brodsworth.

Derbyshire: River Noe and Mam Tor.

Staffordshire: River Dane, Dane Valley; Morridge. Shales below
3rd Grit, Shirley Brook, near Froghall.

Cheshire: River Dane, N. side of Dane Valley; Bosley Minn.

Devonshire: Doddiscombleigh; Pinhoe, near Exeter; Dunsford
Road above Pocomb Bridge, bottom of Ashlake Road, Mincing Lake,
Newton St. Cyres, under Slope Wood and Willhayes Copse ;
near Barnstaple.

South Wales, Pembrokeshire: Penally, near Tenby.

Scotland: Upper Limestone Series: Gare.

Ireland: Pendleside Series: Lisdoonvarna Doon, Mt. Phelim, and
cliffs of Moher and Kilkee, co. Clare; Foynes Island and Rath-
eahill, co. Limerick; Mullaghtumy (Clogher), co. Tyrone; 5 miles
N. of Maynooth, co. Meath; marine bands, Castlecomer Coalfield.

GLypHioceras DAVISI, Foord & Crick. G. reticulatum beds, Hebden
Bridge to Sabden Shales.

Hitherto this fossil has only been found associated with

G. reticulatum, and the study of a series of specimens in my

collection has led me to suspect that it may be an old-age form of

442 Dr. Wheelton Hind—British Carboniferous Goniatites,

that species. Haug, Mém. Soe. Géol. France, Pal., tom. vii, p. 90,
has expressed the same view. Hind & Howe, on ‘the strength of
the locality quoted in the Cat. Foss. Ceph. "Brit. Mus: ;)7p.)) um
erroneously recorded this species as passing up into the Coal:
measures (Q.J.G.S., vol. lvii, app. B).

Yorkshire: The @ reticulatum beds of Horsebridge Clough.

Lancashire: Sabden Shales of Rough Lee.

Staffordshire: River Dane, W. of salmon ladder.

Devonshire: Mincing Lane, near Exeter.

Ireland: Rathcahill and Foynes Island, co. Limerick; Puffing-
hole, Kilkee, co. Clare; Coor Spa Well, near Ennis.

GLYPHIOCERAS ExcavAtuM, Phillips. G. crenistria zone.
Derbyshire: Castleton, Thorpe Cloud, Park Hill.
Staffordshire: Narrowdale.
Isle of Man: Poolvash.
Scotland: Upper Limestone Series: Orchard, Gare, Thornliebank.
Lower Limestone Series: Thornton.

GLYPHIOCERAS BIDORSALE, Phillips.

A species of doubtful value. The late Mr. Crick referred
a specimen in my collection from Horsebridge Clough to this species.
Foord & Crick, op. supra cit., think it may be a form of
G. reticulatum, and observe that the double median saddle on which ~
Phillips founded the species does not exist in well-preserved
examples.

GLYPHIOCERAS BEYRICHIANUM, de Koninck. Middle Pendleside Series
to Millstone Grit.

This species has a most variable form. In the young stage the
umbilicus, is wide and deep, inclusion small, the shell strongly
marked with transverse ribs, the periphery broad and flattened,
and like G. reticulatum has a central spiral sulcus.

In more mature shells the inclusion is more complete, the ribs
more delicate, and the periphery more convex. Haug (op. supra cit.,
p. 92) describes and figures seven distinct varieties, all of which
seem to come from Chokier. Similar varieties occur at Lisdoonvarna,
co. Clare, and Rough Lee near Sabden.

My own observations lead me to suppose that the young stage of
all the varieties are identical and occasionally persist, but the
species was plastic and adopting new forms, or there may have been
actually crossing going on between G. reticulatum and G@. beyrichi-
anum. Many specimens are very difficult to refer definitely to one
or other of these species.

Gastrioceras circumplicatile, Foord,is probably a variety of the species.
Haug points out that G. diadema is a synonym of G. striolatum,
Phillips, and that as he adopts the latter as a distinct species the
name diadema disappears and G'. beyrichianum, de Kon., 1843, takes
its place.

Lancashire: Sabden Shales, Rough Lee (Millstone Grit).

Yorkshire: Gillbeck, 8.E. of Lothersdale (Millstone Grit); Horse-
bridge Clough, Hebden Bridge.

Dr. Wheelton Hind—British Carboniferous Goniatites, 443 ©

Devonshire: Pinhoe Brickfield, near Exeter.

Derbyshire: Spoil-heaps, Edale Tunnel.

Cheshire: Silica quarry, Congleton Edge.

Denbighshire: Holywell Shales.

Pembrokeshire: Black limestones, seashore, Tenby.

Scotland: Upper Limestone Series: Orchard, Thornliebank.
Middle Limestone Series: Black Band Ironstone, Dalry.

Ireland: Lisdoonvarna, co. Clare.

GLYPHIOCERAS sTRIOLATUM, Phillips.

Foord & Crick have included this species as a synonym of
G. diadema. Haug (Trans. Geol. Soc. France) | distinguishes
G. striolatum from G. beyrichianum, and I follow him.

It occurs in the G@. reticulatum beds of High Green Wood and
Horsebridge Clough, near Hebden Bridge.

Devonshire: Pinhoe, Barley, and Dunsford Road, ? Ashlake Road,
Mincing Lake, and Perridge Tunnel.

Scotland: Upper Limestone Series: Gare, Robroystone, Orchard,
Auchenbeg.

GLypaioceras caLyx, Phillips. Pendleside Series to Millstone Grit.

Yorkshire: Horsebridge and Crimsworth Dean; stream S.W. of
Browsholm Hall; River Hodder; Sabden Shales, Gillbeck, S.W. of
Lothersdale.

Ireland: Foynes Island.

GLYPHIOCERAS CompLicatuM, de Koninck. Zone of G. crenistria.

Derbyshire: Castleton, Bradbourne.
This is the first note of the occurrence of this species in England.

GLYPHIOCERAS VESICULIFER, de Koninck. Zone of G@. crenistria.

Yorkshire: El Bolton.
Lancashire: River Ribble, Dinckley Hall.
Isle of Man: Poolvash.

GLYPHIOCERAS PAUCILOBUM, Phillips.

Only one specimen known, possibly the type. Phillips recorded
no locality.

GLYPHIOCERAS SPIRALE, Phillips.

An important Middle Pendleside zone fossil, occupying only a few
feet of strata.

The species occurs at Clavier, Belgium, and in Ireland. Hitherto
all British specimens have been found crushed. I have, however,
been fortunate enough to extract a few uncrushed examples from
nodules near Dinckley, one of which shows the suture-line to agree
with the figure quoted by Foord & Crick after Roemer.

Lancashire: River Ribble, W. of Dinckley Hall; Pendle Hill,
above Lower Pendle Grit; Sabden Shales, Rough Lee, a var. with
fine ornament.

Yorkshire: Embsay Moor, black shales in beds N. of Eastby,
beck three-quarters of a mile 8. of Ashnot; Parkhead, Lothersdale.

Cheshire: Silica quarry, Congleton Edge.

444 Dr, Wheelton Hind—British Carboniferous Goniatites,

Derbyshire: Lower beds of Mam Tor.

Devonshire: Waddon Barton; Bampton; Hele, east of Venn;
Popehouse Close, Christow. é

Ireland: Foynes Island, co. Limerick; Loughshinny; Summerhill,
and near Trim, co. Meath; Killorglin, co. Kerry.

Probably Goniatites granosus, Portlock, from Tyrone, should be
referred to this species.

Genus Nomismoceras, Hyatt, pars.
NomIsMocERAS sprrorBis. G. crenistria to G. striatum zones.
Lancashire: Above the great falls, River Hodder; Ribble at
Dinckley Hall ; Black Hall.
Yorkshire: Rilstone, Crimsworth Dean.
Derbyshire: Storrs Quarry, Bradbourne.
Devonshire: Waddon Barton.
Ireland: Foynes Island, co. Limerick.

NoMisMocERAS RoTIFoRME, Phillips. Generally confined to the
Posidonomya bechert beds.
Lancashire: River Ribble Dinckley Hall. Pendleside Limestone :
above great falls, River Hodder.
Yorkshire: River Hodder below Sandal Holm, and below
bathing cots.
Staffordshire: Pepper Inn Wetton, and Narrowdale.
Isle of Man: Black marble quarry, Poolvash.
Ireland: Loughshinny.
Nomismoceras virracer, Phillips. Upper beds of D2 to
Pendleside Limestone.
Lancashire: Pendleside Limestone: above great falls, River
Hodder.
Derbyshire: Storrs Quarry Bradbourne; Castleton.
Staffordshire: Narrowdale.

Nomismoceras ornatum, Foord & Crick.
Roof of Bullion Coal, Sholver.

Genus Dimorphoceras, Hyatt.
DimoreHoceras GILBERTSONI, Phillips. Base of Pendleside Series to
Middle Coal-measures.

A very widespread form.

Lancashire: River Ribble Dinckley Hall; Rough Lee (Sabden
Shales).

Yorkshire: marine beds of Coal-measures and Pendleside Series:
Crimsworth Dean and Horsebridge Clough; 705 feet above Barnsley
Coal, Brodsworth. :

Staffordshire: River Dane near Dane Bridge; marine bands of
Coal-measures below Gin Mine Coal, 71 feet below 4th Coal, Cheadle ;
the coombes near Leek.

Derbyshire: Pendleside Series of Mam Tor.

Devonshire: Gastrioceras beds, Instow.

Ireland: Pendleside Series of Lisdoonvarna, Foynes Island;
marine bands of Castlecomer Coal-measures.

Dr. Wheelton Hind—British Carboniferous Goniatites, 445

Scotland: Lower Limestone Series: shale over Hosie Limestone,
Thornton, Braidwood, and South Hill, Campsie.

DiworPHOCERAS DISCREPANS, Brown. [Pendleside Series to Coal-
measures.
Yorkshire: Horsebridge Clough and Crimsworth Dean, Hebden
Bridge; Sabden Shales, Rough Lee.
Lancashire: Lower Coal-measures, Sholver, near Oldham.
Ireland : Foynes Island and Lisdoonvarna.

DiworpHoceRas Looney, Phillips. Pendleside Series to Coal-measures.
Lancashire: River Ribble, Dinckley Hall.
Yorkshire: Crimsworth Dean and Horsebridge Clough.
Devonshire: Pinhoe, Exeter.
Ireland: Lisdoonvarna and Foynes Island (Pendleside Series).
Scotland: Lower Limestone Series: Boghead; Raesgill, Carluke ;
Thornton, over Hosie Limestone.

Genus Gastrioceras, Hyatt.
GASTRIOCERAS CARBONARIUM, von’ Buch. Upper Millstone Grit to
Middle Coal-measures.

Lancashire, Yorkshire, Cheshire, and Staffordshire: above the
Upper Mountain Mine or Bullion Coal.

Staffordshire: below the Gin Mine Coal, above Stinking Coal,
Cheadle.

Devonshire: Instow and Clovelly.

South Wales: Rosser veins, Glan Rymney.

GAsTRIOCERAS LisreRI, Martin (?).

There is a great deal of doubt as to what was the original of
Martin’s figure, which resembles a Jurassic ammonoid. This, added
to the fact that the species does not occur at the localities given,
should, I think, cause us to utterly disregard Martin’s figure, and to
accept that drawn by J. de C. Sowerby, Min. Conch., vol. v, pl. D1,
fig. 1, right- and left-hand figs.

Martin says of his shell: ‘‘a common species. It is found in
most of our limestone tracts, particularly near Eyam and Middleton.”’
Sowerby, speaking of the occurrence of the shell, states: ‘‘ This
stratum may be traced from Middleton to near Leeds, and perhaps
further.”

The maximum of G. Lister’ is in the roof of the Bullion, Upper
Mountain, or Hard-bed Coal, and it has not been found higher up
than the Lower Coal-measures, but it certainly occurs below the
Ist Grit or Rough Rock.

Spencer states that he found the species with G. reticulatum at the
Hebden Bridge localities. ‘‘ G. Lister? is very rarely found in the
Millstone Grit rocks of this district (Halifax) . . . and it is only
when we come to the Upper Millstone Grit shales that we find
G. Lister’ occurring in great numbers” (Trans. Manch. Geol. Soc.,
vol. xiii, p. 110).

Yorkshire and Lancashire: Everywhere over the Upper Mountain
Mine or Bullion Coal.

446 Dr. Wheelton Hind—British Ourboniferous Goniatites,

Staffordshire: Below the Rough Rock, Millstone Grit, near po
Devonshire: Instow.
Treland: marine bands, Castlecomer Coalfield.

GASTRIOCERAS coRonATUM, Foord & Crick. Lower Coal-measures.

Lancashire; above the Mountain Mine, Bacup.
Yorkshire: above the Mountain Mine, Shibden.

Genus Prolecanites, Mojsisovics.
PRoLEcanires compressus, J. Sowerby.

A most important zone form denoting the base of the Pendleside
Series, and only occupying as a rule a few feet of beds, except on
Pendle Hill, River Hodder, and Longridge Fell, where a great local
expansion of the Pendleside Limestone occurs.

Lancashire: Warsaw End, Hook Cliff, Little Mearley Clough,
Pendleton Clough, River Hodder below bathing cots, River Ribble
at Dinckley Hall, at dip 2° in stream about one mile N. of
Chipping.

Yorkshire: River Hodder below Sandal Holm, Salterforth railway
cutting, Rilstone, Ingsbeck at base of Pendleside Limestone.

Cheshire: Old limestone quarry near Astbury, below Congleton
Edge.

Devonshire: Coddon Hill, near Barnstaple.

' Isle of Man: Scarlet Quarry.

Ireland: Co. Cork, Little Island and Black Rock, Middleton,

Ballynabintra; Co. Galway, 4 miles east of Loughrea.

PRoLECANITES MicoLoBus, Phillips.
Very rare. Phillips gave Bolland as the locality.

PROLECANITES DISCcoIDES, Foord & Crick. Carboniferous Lime-
e stone, De.
Yorkshire: El Bolton, near Cracoe.
Derbyshire: Park Hill and Brassington.
PROLECANITES SERPENTINUS, Phillips.

A very small shell. Base of Pendleside Series.

Lancashire: River Hodder, River Ribble at Dinckley Hall,
Black Hall.

Pronorites, Mojsisovics.
PronoritEs cycLoLozus, Phillips.
Very rare. Carboniferous Limestone, Dg.
Yorkshire: El Bolton, probably ; Gr assington is quotedin Phillips's

list of errata.

Derbyshire: Thorpe Cloud.

NEW GENUS.
Saeirroceras, Hind.

The genus is founded on a single specimen which consists of
three-fourths of a complete individual. A large portion of the body-
chamber is present, which on removal reveals the greater part of
the penultimate whorl with the camere and suture-lines.

I obtained the specimen from Keal Hill, one of the well-known

Dr. Wheelton Hind—British Carboniferous Goniatites. 447

Craven Knolls, It was in a block, on the south side of the hill, and
from the accompanying fossils and nature of the rock came from the
immediate vicinity. ‘he beds on Keal Hill belong to the Upper
Dibunophyllum horizon and are succeeded by the shales and black
limestones of the Pendleside Series. Glyphioceras crenistria,
G. striatum, and G'. truncatum are common at the horizon at which
the fossil was found.

I showed the specimen to the late Mr. G. C. Crick and left it
with him for description, but his untimely death prevented him
from publishing our views. He agreed with me that the suture- line
denoted an ammonoid genus quite new to science.

Generic Characters.—Shell involute, discoidal, compressed with
an acute periphery. Sides flattened. Umbilicus large and open.
Camere numerous. Suture: an acute median saddle, external
lobe broadly rounded, external saddle acutely linguiform, lateral
lobe deep, rounded, linguiform, lateral saddle raised, acutely
pointed, second lateral lobe broad and obtusely rounded.

SaGITTOCERAS AcuruM, sp.nov. (PI. XVI, Figs. 1, la, 16.)

Specific Characters.—Shell discoidal, much compressed, with an
acute periphery. Whorl sagittate in section, much higher than
broad, inclusion about three-fourths; whorls 3 or 4. Umbilicus large
and open, sides smooth, very gently convex, sloping towards the
umbilicus, the edge of which is subangular and its margin convex.

Body-chamber occupies about one complete whorl. Camere
many, about 20 to the whorl.

Suture as given under description of the genus above. ‘Test thin,
apparently smooth.

Dimensions. — Diameter, 83 mm. approximate; transversely,
30mm. estimated.

Locality.—Upper Dibunophyllum zone of Keal Hill, Craven,
Yorkshire.

Observations.—Dr. Foord! described under the name Brancoceras
enniskillent an acutely keeled Goniatite from the Carboniferous Lime-
stone of Blacklion, near Enniskillen, in the Griffiths’ Collection in
the Science and Art Museum, Dublin, but the small umbilicus and
general shape of the shell do not show any relation to that now
under description, and Dr. Foord states that he saw the sutures and
had ‘‘no doubt as to their being those of Brancoceras”’

I obtained a fragment, two-thirds of a shell, which I refer to Foord’s
species, from the Carboniferous Limestone of Carsington, Derbyshire.
The small umbilicus and greater thickness and less acutely angled
periphery separate it at once from Sagittoceras acutum.

In external appearance S. acutum has a close resemblance to
Phacoceras oxystomum, and may easily be mistaken for it if the
suture-line is not seen.

The suture-line distinguishes the genus from all other Carboniferous
forms by the rounding of the peripheral lobe, the acutely pointed
external saddle, the presence of two lateral lobes, and a_ well-
developed lateral saddle (Pl. XVI, Fig. 1a).

1 Carb. Ceph. Ireland, p. 208, pl. xlvii, figs. 3a, b.

448 Dr. Wheelton Hind—British Carboniferous Goniatites.

Pericyclus virgatus, de Konineck, has a lateral saddle and lateral
lobe, but the shape of saddles and lobes are quite distinct from the
genus under description. Pl. XVI, Fig. 1, shows the specimen
after the body-chamber has been detached.

PericycLus pivaricatum, Hind, 1905. (Pl. XVI, Figs. 2-6.)
Glyphioceras diwaricatum, Hind, Proc. R. Irish Acad., vol. xxv, ser. B, No. 4,
p. 144, pl. vi, fig. 6.
? Pericyclus virgatus, Foord & Crick, Cat. Foss. Ceph. Brit. Mus. Nat. Hist.,
pt. iii, p. 146.

Since the publication of this species much fresh material has
accrued from many localities. The suture-line has also been seen
and more perfect specimens examined. I now think it should be
more correctly placed in the genus Pertcyclus, Mojsisovics. I showed
much of my material to the late Mr. Crick, and he expressed agree-
ment with my conclusions. In many of the fossil lists I have
published this species has been confused with G. beyrichianum.
As the species was erected on fragmentary specimens I think it
best to redescribe and refigure it in more detail. Its lowest known
occurrence is in the Posidonomya becheri beds of the Pendleside
Series, but it goes up as high as the 3rd Grit Shales of the Millstone
Grit.

Specific Characters.—Shell discoidal, compressed, umbilicated,
attaining a diameter of 70mm. Greatest thickness at umbilical
margin. Height of outer whorl, four-sevenths of the diameter of the
shell. Whorls seven or eight, inclusion in the inner whorls almost
mil but becoming in the outer three or four more and more complete.
Umbilicus deep, open in the young, becoming relatively more
narrow with the growth of the shell, its margin rounded, the
under surface bevelled. Whorl elliptical in section, deeply im-
pressed by the preceding one. Periphery narrow, convex, becoming
obscurely keeled centrally in fully grown shelis. Very feebly
convex at the sides. Body-chamber occupies two-thirds of the last
whorl. Suture-line as shown in Fig. 6.

Test ornamented with many flattened ribs which bifurcate about
half-way between the umbilicus and the periphery. The grooves
between the ribs, linear at first, become broader and equal, about
half the measurement of the ribs in breadth. The ribs arch
forward on the side, but on the periphery form a fairly deep sinus
with concavity towards the younger part of the shell. A specimen
from Cracoe Fells shows also spiral marking on the ribs.

Dimensions.—Greatest diameter, 70 mm.; width at umbilicus,
25mm.

Localities. —Pendleside Series: silica quarry, Congleton Edge,
Dinckley Hall River Ribble, Flasby, in watercourse between
Butterhaw and Shelterton, andS. of Shelterton, Horsebridge Clough,
near Hebden Bridge. Posidonomya becheri beds: Poolvash, Isle of
Man.: Millstone Grit Shales: Eccup, near Leeds. Ireland: Foynes
and Foynes Island; Lisdoonvarna, in the Pendleside Series.

Observations.—The flat dichotomous ribs distinguish this species
from all other described forms of the genus. P. virgatus,
de Koninck, sp., has more rounded ribs, and these are not dichotomous.

Dr. Wheelton H ind—British Carboniferous Goniatites, 449

Foord & Crick, Cat. op. supra cit., refer doubtfully some specimens,
said to be from Halifax, to P. wirgatus; they remark, ‘‘ De Koninck
says the ribs are not dichotomous, but they certainly are in these
specimens up to a diameter of 16mm.’’ hese shells most probably
belong to the species under description. The species alters its habit
with age. In the young the shell is much more globose and the
ribs more transverse than in the adult, when the shell is more
discoidal and compressed and the ribs sinuously curved on the side
with a deep peripheral sinus.

The young stage may be confused with some forms of G. beyrichi-
anum, but the umbilicus in the latter is much wider and inclusion
less. ‘he transverse ribs less close and more acute.

Pericyclus impressus, de Koninck, 1880. (Pl. XVI, Figs. 8-10, 12.)
Ann. Mus. Roy. d’hist. Nat. Belgique, tom. v, pt. ii, p. 118, pl. xlix, fig. 3.

Specific Characters. —Shell subglobose, involute, umbilicated.
Whorls six, inclusion extensive, somewhat obtusely lunate in
sections not very high. Umbilicus large and open in the young
stages, becoming narrow with age; its border rounded, sides convex ;
the periphery convex.

Body-chamber occupies the last whorl. Camere four to a
quarter of an inch. Suture as drawn below (Pl. XVI, Fig. 126).

Test thin, with many simple transverse subangular ribs, the sulci
between which have numerous fine spiral lines. On the periphery
the ribs have only a suspicion of a hyponomie sinus.

Dimensions.—Fig. 9, Pl. XVI, measures, diameter 18 mm., trans-
versely 10mm.

Loculity.—Millstone Grit Shales (Sabden Shales). Gull beck, near
Cowling, Yorkshire.

Observations.—De Koninck’s types were obtained from Véve,
assise i. ‘The umbilicus at once distinguishes the species from
others of the genus.

In the young the ribs are much less numerous, and the umbilicus
wide, inclusion very small (Pl. XVI, Fig. 10).

All the specimens obtained were from one bullion in shale, a quarter
of a mile above Stonehead Farm.

Prricyctus vireatus, de Koninck, 1880. (Pl. XVI, Fig. 7, 7a.)
Ann. Mus. d’hist. Nat. Belgique, tom. vy, pt. ii, p. 118, pl. xlix, fig. 4.

I have two fragments of the body-chamber and one crushed
example of this species from the Redesdale ironstone.

In his description de Koninck says, ‘‘ Umbilie assez étroit a bords
anguleux et infundibuliform,”’ but his figure shows a moderately
sized umbilicus with a convex border. The ribs are more numerous
and flatter than in P. funatus, Sow., and less flat and less regularly
dichotomous than in P. divaricatus, Hind. De Koninck’s specimen
was obtained at Visé. ‘

PERICYCLUS REDESDALENSIS, sp. nov. (Pl. XVI, Figs. 13, 13a, 130.)

Specifie Characters.—Shell moderately inflated, sides flattened.
Eyolute, umbilicus about 3%;in. in diameter, greatest thickness half-
way between the periphery and umbilicus. Inclusion extensive.

DECADE VI.—VOL. V.—NO. x. 29

450 Dr. Wheelton Hind — British Carboniferous Goniatites.

Height of last whorl about half the diameter. Whorls ?4, oval in _
section, broader than high, indented by preceding whorl. Umbilicus
with somewhat raised and rounded margin and convex inner area,
infundibuliform. Periphery very convex, marked off, in casts, from
the lateral area by a spiral groove. Body-chamber occupies almost
a complete whorl. Test unknown except on inner area of umbilicus,
where there are many distinct, closeribs. The cast shows indications
of numerous strong curved ribs, with a deep sinus backwards on the
periphery. Suture-line as figured (Pl. XVI, Fig. 130).

Dimensions.—Diameter, 43 mm.; transversely, 17 mm.

Locality.—Redesdale Ironstone, Northumberland.

Observations.—Hitherto this shell has always been confused with
G. truncatum, Phillips, from which it differs essentially in the shape
of the periphery, which is less angular, the lateral area is less
compressed, and possesses a spiral groove. The suture, too, has
marked differences in the central saddle and peripheral lobe.

The late Mr. Crick pointed out to me that Fig. 13, Pl. XVI, shows.
an interesting condition of growth. The last septum is perfectly
formed (a), a second septum was being formed (d), and a third
septum is faintly indicated by a line forming the boundary of the
muscle attachment. The sudden rise forward of this line indicated
the commencement of the shell muscle. The spiral line on the left
side of the shell is half an inch away from the margin of the
umbilicus, while that on the right is much closer, only a quarter
of an inch away. A younger specimen shows no spiral groove at
all, so it probably is only an old-age character.

EXPLANATION OF PLATE XVI.
FIG.
1. Sagittoceras acutwm, sp. noy. #3 nat. size.
la. Id. The suture-line. 4 nat. size.
1b. Id. In profile. 3 nat. size.
2. Pericyclus diwvaricatum, Hind. 2 nat. size.
2a.Id. Inprofile. #2 nat. size.
3. Id. Showing the ornament. 4% nat. size.
4, Id. The young stage.
4a. Id. In profile.
5. Id. The ornament and orifice in adult. 4 nat. size.
6. Id. The suture-line. #% nat. size.
7. P. virgatus, de Koninck. 4 nat. size.
7a. Id. In profile. 3 nat. size.
8. P.wmpressus. Showing the ornament. x 2.
Sa. Id. In profile. x 2.
9. Id. Cast.
9a. Id. In profile.

10. Id. The young stage. x 4.

12. Id. Side view showing the ornament. x 2.

12a. Id. Inprofile. x 2.

12b. Id. The suture-line. x 2.

13. P. redesdalensis. Showing (a) last suture completely formed, (b) new
suture commencing, (c) line forming the boundary of the muscular
attachment. 4 nat. size.

13a. Id. In profile.

136. Id. The suture-line.

Grot. Maa., 1918. 2 Prate XVI.

G. M. Woodward, del

Bale, Sons and Danielsson JI_td

BRITISH CARBONIFEROUS GONIATITES.

Sir H. H. Howorth—Geological History of the Baltic. | 451

Il.—Tue Recent Grotogican History oF rHE Bartic anpd ScaANnnDI-
NAVIA AND ITS IMPORTANCE IN THE Post-Trrtiary History oF
Wesrern Europe.

By Sir Henry H. HowortsH, K-C.1.H., F.R.S., F.S.A., F.G.S8.
(Concluded from the September Number, p. 409.)

ET us now turn to the lessons presented by the Mollusca found in

the raised beaches of Norway and Western Sweden.

Milne-Edwards was the first to discriminate the European
molluscan fauna into geographical provinces. This he did in
a paper in the Ann. Sci. Nat., 1838, p. 10. He separated our
European seas into two provinces, which he called the Seandi-
nayian and the Celtic. The latter included the English Channel,
the coast-lands from Ireland to Gibraltar, and those of the
Mediterranean.

S. P. Woodward, in his Manual of the Mollusca (1851-6), pt. 111,
ch. ii, ‘‘Geographical Distribution,” pp. 357-61, 1856, makes the
Faeroe and Shetland Islands and the coast of Norway from the North
Cape to the Naze a part of his ‘‘ Boreal province” (ii, p. 857) and
leaves the British Islands, Denmark, Southern Sweden, and the
Baltic in Milne-Edwards’ Celéie province (ili, p. 359).?

The coasts southwards from the English Channel to.the. Canary
Islands, and those of the Mediterranean, 8. P. Woodward named
the Zusitanian province (iv). These names have maintained their
place. To these provinces has been added an Arctic one, which was
apparently first suggested by S. Loven in 1896. The names were
accepted by the elder Sars, who, however, limited them; thus the
Arctic province with him comprised only” the cireumpolar area
bounded by the Arctic Circle. The Boreal region he extended from
the Arctic Circle to Cape Finisterre, in about lat. 48°. South of this
and including the west coast of France, Spain, Portugal, the
Mediterranean, the Azores, and the north-west coast of Africa to the
Canaries he included in his Lusitanian region. The younger Sars
in his fine work on the Arctic fauna of Norway altered the boundary
of his father’s Arctic province so as to include the Lofoten Islands.
His new boundary passed through the North Cape. He justified
the diversion of the line in the latter place because of the Gulf
Stream, which causes a great difference between the east and west
coasts of that promontory, thus creating a similar frontier to that

caused by Cape Cod in North America.

These divisions (like all classifications of natural objects) are,
of course, very largely arbitrary, for the different classes naturally
overlap. Wherever we put down our dredge in the European area,
or wherever we sort the shells from a raised beach, we shall meet
with the fact that some of the molluscs have a very elastic and
adaptable constitution. They can live and thrive in many varied
conditions if they can only get food, and we always have to be
careful in making general inductions from a single species or small

' Of 289 Scandinavian shells catalogued by Dr. Loven, 217, or 75 per cent,
are common to Britain,

452 Sir H. H. Howorth—Geological History of the Baltic.

group of species, especially if we are tied down to some theory
which has to be supported at all costs and which distorts our vision
when we look the facts in the face. It is only too easy to select
a number of shells which seem to thrive as well in the Scandinavian
or British seas as in the Arctic Ocean, to dub them Arctic and
then to apply the term Glacial to a deposit. Again, even the best
of the older conchologists have at times failed to discriminate
small differences and varieties which may entirely sophisticate the
conclusion. I will quote a good example which happens to be very
familiar to me because I wrote a monograph on the shell, viz. Mya
arenaria, which was published in the Proceedings of the Zoological
Society... There can be no doubt from the evidence that JL arenaria
is a new addition to the fauna of the North Sea and its outliers.
There is no evidence that it existed there before the beginning of the
seventeenth century. It was first described by Lister in 1678.

Gwyn Jeffreys, who did not know this, in his account of the
Mollusca of the Uddevalla raised shell-bed, not only claimed to have
found this species of J/ya there, but made a somewhat characteristic
deduction in regard to it. He described it as an Arctic shell, and
says of it, ‘‘ The occurrence of this cireumpolar shell-fish so near the
Tropic of Cancer probably indicates the most southern limit in space
of the Glacial epoch”? (British Conchology, 111, pp. 65-6).

Jensen, a much more critical person than Gwyn Jeffreys, has, in
fact, proved most completely that Jf arenaria is not an Arctic shell
at all and does not exist in the Arctic regions. Gwyn Jeffreys
had mistaken another and very different species with an entirely
different habitat for it, namely J. truncata, var. ovale, which is
a very high Arctic shell and has been found in Iceland, Greenland,
Spitzbergen, Nova Scotia, and the Kara Sea. The mistake of Gwyn
Jeffreys was a particularly unfortunate one, because it was copied
into several geological works and made the basis of several most
illegitimate deductions. (For details of the whole discussion I must
refer to my paper in the Proceedings of the Zoological Society,
1909, pp. 745-67).

On several other occasions, as it seems to me, Gwyn Jeffreys used
the word “ Arctic’? as applied to the habitat of certain shells from
the raised beaches in a very arbitrary way.

It does not follow, again, that when truly Arctic shells are found
in more southern waters they should be always dubbed as Arctic.
Before so naming them we must be careful to consider measurements
and other differenti. Many Arctic shells occur in our Northern seas
which only attain their normal and typical size in very high latitudes
and become dwarfed in size and otherwise modified further south.
There are others which ought not to be called Arctic at all, because
they thrive just as well in temperate regions as they do in Arctic
ones, having the adaptability of Scotchmen. So that considerable
care and judgment are required in order to justify the application of
the term ‘‘ Arctic” to groups of Northern shells.

1 “* Some living Shells, their recent Biology, and the light they throw on the

latest Physical Changes in the Earth [| Mya arenaria],’’ by Sir H. H. Howorth
(Proc. Zool. Soc., 1909, pp. 745-67).

Sir H, H. Howorth—Geological History of the Baltic. 458

In Brogger’s admirable monograph on the molluscs of the raised
beaches in the Christiania Fjord he has compared the living fauna of
this great Norwegian bight or inlet with that in the later raised
beaches of Norway, and has shown that a certain number of the
molluscs now found living in Norwegian waters are not found in
these beaches at all, and he very naturally infers from this that they
have invaded these waters since the latest beaches were deposited,
a large proportion of them having probably come as a direct or
indirect consequence of human effort.

It is interesting to analyse these immigrants. Five of them
which seem to thrive and flourish in the temperate waters of the
Christiania Fjord belong to the highest latitudes. They are Acmea
testudinalis, Lophyrus albus, Scalaria Groenlandica, Cerrthropsis
costulata,’ and Nucula delphinodonta.- The notable thing about
these five high Arctic shells is that not only are they not found in
either of the two sets of raised beaches in the Christiania Fjord, they
are also not found on the Arctic shores of Northern Asia from the
Kara Sea eastwards, but occur abundantly in the Arcticlands of the
New World from Behrings Straits to Greenland, and Brogger has no
hesitation in treating them as Nearctic shells which have migrated
in late historical times to Europe, having, not improbably, been
transported by whalers and seal-fishers. The notable thing to
remember about them is that they seem to thrive under such new
conditions.

We will now turn to a number of Bornan species which have,
probably, found their way into the Norwegian waters in recent years,
notably :—

Mya arenaria (of which we have spoken above), Tellina pusilla, Macoma
tenuis, Psammobia tellinella, Rupicola distorta, Neera rostrata, and Risso-
stomia octona, all recent introductions from the West.

_ Lastly the Lusrranrawn species, which have immigrated since the
latest raised beds were laid down, viz. :—

Lima hians, Modiolaria marmorata, Nucula nitida, Sphena Bingham,
Teredo navalis, Trochus zz yphinus, Hydrobia ventrosa, Onoba costata,
Cingula senustriata, Turbonilla scalaris, Stulifer Turtont, Mangelia attenuata,
M. striolata, Scalaria Tur toni, Aplysia ‘punctata.

It is not possible to know how these vagrants found their way into
Scandinavian waters during a period when the climate, as we shall
see presently, has been only slightly changed, nor would a change of
climate avail as a reason, for the newcomers belong to different
marine climatic regions. In regard to the Lusitanian migrants
I have a theory which I think interesting, but must postpone to
another paper.

From these recent comers we will turn to the shells which are
found in the /ater raised beaches, but no longer live in the neigh-
bouring sea. The total number of shells from these beaches is 255.
Forty of these are Arctic, 103 Boreal, and 112 Lusitanic. Of these
210 are now living, leaving 45 species represented in the beaches

1 This species, which does not occur in the beaches of the Christiania Fjord,
has been found in those at Uddeyalla and in Britain.

454 Sir H. H. Howorth—Geological History of the Baltic.

but not now living in this region, 14 of which are Arctic, 9 Boreal,
and 22 Lusitanic.

The 14 Arcric forms are :—
Terebratella Spitzbergensis, Pectenislandicus, Portlandia lenticula (?), Tridonta
borealis, Panopea Norvegica, Molleria costulata, Margarita Groenlandia,
M. cineraria, Morvillia undata(?), Marsenina micronphala, Trichotropis
borealis, Littorina palliata (?), Sipho togatus (?), and Utriusculus pertenuis.

The 9 BorEaL species are :—

Gwynnia capsula(?), Montacuta Viringit, Solen ensis (?), Cadulus propinquus,
Lamellaria latens, Auriculina diaphana, Sipho gracilis (?), Neptunea
antiqua (?), and Utriculus obtusus.

The 22 Lusrranic species are :—

Arca tetragona, Cardiwm tuberculatum, Tapes decussatus, Levton syuamosum,
Scrobicularia piperata, Lasea rubra, Tellina crassa, Macoma fabula, Psam-
mobia vespertina, Solecurtus antiquitatus, Pholas candida, Cingula soluta,
Onoba vitrea, Alvania reticulata, Aclis ascaris, A. unica, Turbinella lactea,
Odostomia albella, Culinella nitidissima, Clathurella purpurea, Mangelia
nebula, Philine pruinosa.

(Brégeger, op. cit., pp. 577, 578.)

Some species like Jsocardia cor, existing both in the beaches and
living, were formerly very common in the Christiania Fjord, but are
now very rare; others are decidedly rarer now than they were, such
as Pecten varius, P. septemradiatus, P. opercularis, and the oyster.

In one matter I would take exception to Brogger’s classification of
the later beaches, which he groups together under the name post-
Glacial beds. Having named the greater number of them Zapes beds
from the presence in them of that very characteristic shell, he
proceeds to treat others, which agree with the Zapes beds virtually
in all their other contents but in which the Zapes have not been
found, as belonging to a different horizon. This seems to me to
introduce a quite unnecessary complication into the problem,
unjustified by the evidence. There are only a limited number of
molluscs which are sufficiently elastic to live under very different
conditions of food and bottom, and the occasional absence of a
particular shell is often merely due to peculiar local conditions.

Every shell-collector knows as an elementary fact that when we
pass from clay to mud or sand or gravel or rocks, we at once lose
certain of the species which are perfectly contemporaneous and
which are now living in different parts of the coast of the same
sea. The complete absence of the Zapes and the oyster from the
modern Cattegat, although they were abundant there before the ~
Baltic breach, shows that they were not capable of tolerating certain
changed conditions like others of their companions could, and we
must in such cases take the general facies of the contents of the beds,
and not the presence or absence of a particular shell, as justifying us
in creating a new horizon.

In regard to the dying out of the forms it is not easy to give an
entirely satisfactory explanation, for they belong to all three of the
geographical provinces into which the mollusca have been divided
by Brogger. It is possible that the reduction in the salinity of the

Sir H. H. Howorth—Geological History of the Baltic. 455

water due to the outflowing of so much fresh water from the Baltic,
which certainly destroyed some, may have had a wider influence
than we know. Another cause to which we will turn presently is the
great shallowing of the water in certain cases, and a third a possible
change of the temperature of the water affecting the supply of food.
What is important to remember is that the mollusca represented by
the so-called post-Glacial beds belong essentially to that of the
Tapes beds of the Cattegat beaches, and that although Tapes is
extinct in the Christiania Fjord, two species of the genus are no
longer found there, but are still found living in the North Sea and on
the Western Norwegian coast. Dr. Brogger, in fact, as I have said,
calls the greater number of the beds occurring in the Christiania
Fjord, which he classes as post-Glacial, the Zapes beds.

I would venture very deferentially, therefore, to differ from him
in allocating anything more than a quite relative value to the
presence or absence of any particular shell from a bed as a test of its
age or homotaxis. JI would treat them as the result merely of
different local surroundings and as being entirely local divisions, and
in this case I would name them all Zapes beds, and use that name
in the sense in which Dr. Brogger uses the name post-Glacial beds.

-Turning to these lJater or so-called post-Glacial beaches in the
Christiania Sound, I will give a list of some of their heights above
sea-level as reported by Sars (op. cit., p. 3):—

On the east side of that Gulf. Heights above sex level:

eet,
Skullerud in Héland . : | : 437
Nordby on the Ogdered Lake : : : 516
Sververud (Oppegaard) near Hidsberg . ‘ 540
Killebo and Damholt in Rakkestad : 440, 475
Kolbjérnsvik in Aremark . é . 400, 410, 455
Skjaedal, Hellesaa : : : : 3 476-454
Bjérndal in Aremark . 5 : : : 385-375
Sandbol-Skjaeldal : p ‘ : ! 350
Moen in Aremark : : : : : 457

To each of these numbers Sars would add 90 feet in order to ascer-
tain the actual depth at which the molluscs live.

Let us now turn to the high Arctic beds, which have a good deal
more importance and interest for us than the later or post-
Glacial ones.

I have stated that in the Christiania Fjord and in the northern
part of the Cattegat, in addition to the Zapes beds which occur at
different levels, we have another series unmistakably contrasted with
them, since they only contain shells belonging to an extreme Arctic
type, while on the other hand the two sets of beds have none of their
shells in common, so that in dealing with them we get rid of all
the difficulties of overlapping. These beds have been called from
their most characteristic shell Yoldia clays. They present some
eritical problems in which I find myself in sharp difference with the
Northern writers.

The fauna of these beds comprises the following twenty-six species
of molluscs and a number of varieties.

|

456 Sir H. H. Howorth—Geological History of the Baltic.

SPECIES AND VARIETIES OF SHELLS CHARACTERISTIC OF THE
: YOLDIA CLAYS.

1. Macoma (Tellina) calcarea, var. 14. Neptuneadespecta, var.carinata.

maxima, 15. N. denselirata, n.sp.
2. Saxicava arctica, var. 16. Sipho togatus, var. Pfaff, var.
Uddevallensis. sinuosa, var. vallensis.

3. Pecten rslandicus. 17. S. brevispira.

4, Leda pernula, var. costugera. 18. S. islandicus.

5. Nucula minuta. 19. S. Verkriitzent, var. plicifera.

6. N. tenuis, var. expansa. 20. Trophon truncatus, var. major.

7. Lyonsta arenosa. 21. Cylichna Remhardti.

8. Lepeta cocca, var. major. 22. Modiolaria mgra.

9. Natica affinis, var. clausa. 23. Portlandia arctica = Yoldia
10. Lunatia Groenlandica. arctica, var. siliquwa, var.
11. Astarte undata. portlandica, var. inflata, var.
12. Buccinumterra-nove,var.grandis 24. Yoldia hyperborea.

and var. a. 25. Admete viridula.
13. B. hydrophatium, var. elata, 26. Bela nobilis, var. rugulata.

var. fusco-rufescens, var. textw-
lata.

(Brégger, op. cit., pp. 31, 32.)

Of these species and their varieties 26 have been found at
Glommen between Sarpsborg and Frederikstad, 11 at Sandefjord,
8 at Tonsberg, and 9 at Moss.

From the Voldia clay at the last named of these places Brogger
also enumerates a number of Foraminifera, and among them he
characterizes Polystomella arctica as being a high Arctic species
(op. cit., 33 and 670).

I will now give the living habitat of some of the above shells :—

Macoma calcarea. The coasts of North Siberia and North America,
Greenland, and Spitzbergen.

Saxicava arctica. The Kara Sea and North Siberian coast and West and
North Greenland.

Pecten islandicus. Greenland and Finmark.

. Leda pernula, var. costigera. North Siberian coast and Greenland.

Nucula tenuis. North Siberia coast, Spitzbergen, Melville Bay, and
Greenland.

Lyonsia arenosa. Nova Zembla and West Greenland.

Lepeta cocca. Greenland and Grinnell Land.

Natica affinis: The Kara Sea and generally circumpolar.

Lunatia Groenlandica. North coast of Asia, Greenland, and generally
circumpolar.

Astarte undata. Kara Sea, north coast of Asia, Spitzbergen, and
Greenland.

Buccinum terra-nove. Nova Zembla, North Siberian coast, the islands
of the St. Lawrence, and Greenland. s

B. hydrophanum. Kast Greenland and Spitzbergen.

Neptunea despecta. Finmark, Nova Zembla, and north coast of Asia.

Sipho togatus. Kara Sea, north coast of Asia, and Spitzbergen.

S. islandicus. Nova Zembla, north coast of Siberia, Gulf of St. Lawrence,
Spitzbergen, and Greenland.

Trophon truncatus. North coast of Siberia and Greenland.

Cylichna Reinhardtt. Nova Zembla and north coast of Asia.

Modiolaria arctica. Finmark.

Portlandia arctica. Nova Zembla, the Yenissei, Franz Joseph Land, and
Greenland.

Yoldia hyperborea. Greenland, Spitzbergen, and Finmark.

od

Sir H. H. Howorth—Geological History of the Baltic. 457

In a few instances we find that these shells have occasionally
wandered somewhat south of the Arctic Circle, but generally” the
more southern specimens are dwarfed and distorted.

These deposits of Arctic shells have been named after a very
characteristic Arctic molluse formerly ‘Sowa as Yoldia arctica and
now as Portlandia arctica.

It is only lately that the widespread occurrence of the Yoldia in
the raised beds of Scandinavia has been ascertained. Hisinger was
the first to find it in Scandinavia at Aker in West Gothland in 1837,
while Torell found it in a submarine clay at Varberg in 1848. It
was found on the shores of the Malar Sea in 1852. Sars found it in
Southern Norway in 1861 and described it from there in 1868 and |
1865. Presently Esmark found it on the west side of the Bight at.
Sandefjord and Ranviken. It was Brogger, however, who added
so greatly to the number of its known sites, thirty of which are now
known. Ofthese he enumerates twenty-four from the Christiania
Fjord (op. cit., 669-70). He gives full details with a map on
pp- 8-454 to the same work.

At Wenersborg A. Lindstrom found the shell and other shells,
while at Gothenburg Torell met with it a few metres above the sea;
V. Munthe found the same shell at Kollekan and on the island of
Tjorn in Bohuslin, in the former case at a height of 5 to 7 feet and
in the latter at 10 feet above the sea-level. With it occurred
Pecten wslandicus, Portlandia arctica, Macoma ( Tellina) calearea, and

Saxicava rugosa.

Crossing over the Cattegat we have a similar set of beds which
have been described by Johnstrup, V. Madson, and A. Jessen from
Vendsyssel, that strip of North Jutland forming a long narrow
peninsula separated from the mainland by the Limfjord. The species
found in the Yoldia beds of this district consist of Modiolaria discors,
Nucula tenuis, Leda pernula, Portlandia arctica, P. lenticula, Axinopsis
orbiculata, Axinus flexuosus, Macoma calcarea, M. mosota, M. crassula,
Lyonsia arenosa, Mya truncata, Saxicava pholadis, Natica sp., Bela
nobilis, Trophon clathratus, Buccinum Groenlandicum, Neptunea despecta,
Cylichna Reinhardti, Utriculus pertenuis. On this list Brogger
comments thus: The commonest species are Saxicava pholadis,
Portlandia arctica, Modiolaria discors, Macoma calcarea, M. crassula,
and Cylichna Reinhardti.

All these species, with the exception of Azinopsis orbiculata, are
living in the Kara Sea and also in the Greenland seas. The fauna
from Vendsyssel, he continues, has the same Arctic character as that
of the Yoldia beds of the Christiania Fjord, although not quite the
same species. Jessen has found the Yo/dia clay in this district as
high as 33 metres.

In the island of Laes6é in the Cattegat, according to Jessen, the
same high Arctic species have been found at an elevation of 3 metres
and more. From Halland and Dalsland in Western Sweden the
Yoldia beds have long been known. Hisinger was the first to find
Yoldia at Akersvass and Trollhatten, and with it a number of other
molluscs from 12 to 15 metres or 40 to 50 feet above the sea-level.

In Western Norway Torell found it in 1860 at Lademoen and

458 Sur H. H. Howorth—Geological History of the Baltic.

Baklandet in Trondhjem, and his discovery was recorded by Sars in
1865. Here it was 123 metres above the sea. Kjerulf reported
similar finds at Klabu, Selbu, and Nidelven in the same province,
apparently up to 130 or 150 metres (ibid., 124-9). In Nodland
and at Nidelven it was found by Rekstad. j

I have described the localities where the Yoldia fauna has occurred
in considerable detail because of the important place which it
has filled in geological polemics, and because for a long time the
deductions based upon it had to be supported by very limited
examples. It is now. cbvious that the fauna was widely spread
over the area once occupied by the Christiania Fjord, the northern
Cattegat, and the Eastern Gulf, which included the Great Lakes of
Sweden.

Let us now turn to the lesson which these beds have to teach us
and which I claim have been completely misunderstood. There is no
question about Yoldia and its companions being very high Arctic
shells, nor is there any ambiguity in interpreting the evidence caused
by the mixture of shells occurring in other beds or living under more
temperate conditions. It is perfectly plain that at the horizon
where these shells lived the temperature must have been very low.
This is indisputable. There are other facts, however, which preclude
the explanation of their surroundings offered by Brogger, and which
have led him and many others, including the late Professor James
Geikie, to postulate that when they were living Scandinavia must
have been under glacial conditions. I especially propose to deal
with Brogger’s arguments.

First, then, about the relative position of the Yoldia beds to the
later or Tapes beds, and especially in the Christiania Fjord where they
occur together. The Yoldia beds in this district do not occur higher
than from 40 to 50 metres or a little more above thesea-level, while
the later beds in which the molluscs are virtually the same as those
now living in, the adjoining sea have been found by Mr. Oyen at
Grefsen and Arvold, near Christiania, as high as 203 to 208 metres
(Brogger, op. cit., 698). I have given a series of other heights
attained by them in this district in an earlier page. The Yoldia
clay, says Broégger, occurs at the height of 40 to 60 metres in some
places. At lower levels, he says, they occur at Nevlung, Laven,
Sandefjord, Tonsberg, Asgards Strand, Horlten Moss, and Rade, by
the Glommen, etc., on the present shore-line and only a few metres
above it. ‘I'hat is to say, in this district. the Zapes beds lie far above
the Yoldia beds. Elsewhere the two sets of beds occupy the same
relative position towards each other wherever they occur together in
other parts of Scandinavia. It seems to me inevitable that this
involves the conclusion that the Zapes beds emerged from the sea
before the Yoldia beds. That is the conclusion Brogger has himself
drawn in the similar case of the Ancylus beds and the Lztorina beds
of Sweden, and it cannot be evaded.

It is also plain that the molluscs of the upper or Tapes beds, which
are rich in the number of species, are, with very slight and negligible
exceptions, all of the same forms as those now living in the
adjoining seas, while none of those in the Yoldia beds are now

Sir H, H. Howorth—Geological History of the Baltic. 459

living there. Not only so, but it is plain that whenever and where-
ever they lived they were surrounded by Arctic conditions. This is
indisputable. What I dispute is that they in any way testify to —
a Glacial period. If they did so, that Glacial age must have inter-
vened between the period when the Zapes beds were uplifted and the
present conditions of climate in the Scandinavian seas, which
biologically are duplicates of each other. This would mean, first,
that the postulated Glacial period was intercalated between two
periods marked by the same temperate marine fauna. In other words,
the fauna of the Zapes beds must have been entirely exterminated by
the extreme Arctic climate of the Yoldia period, and then the latter
must in turn have been similarly exterminated and replaced by the
older inhabitants, after which a return to precisely the same
conditions again took place.

Apart from all other considerations, the proposed theory involves
not merely a gradual change of climate, but a sudden and drastic
one, or else there would be some evidence of a gradual transition of
fauna, whereas there is none, but a complete and drastic change of
the whole fauna. Secondly, there is the puzzle of explaining
whither the remnants that escaped the extermination fled, and
whence they could return to their old homes in better times.

Surely such a position is preposterous and unbelievable unless
supported by overwhelming evidence. As a matter of fact,
Dr. Brogger produces no evidence at all, but only a quite fallacious
deductive argument. He says quite rightly that in the high
Arctic sea where the Yoldia and its companions are found, they
mostly hve at a depth of from 10 to 30 metres, a number of them,
he adds, living at greater depths (op. cit., 681). He then goes on
to argue that the same species of molluscs when it lived in the
Scandinavian seas must have lived at about the same depths,
notwithstanding the great difference in latitude. To justify the
immense postulate he relies on the still more wilful one of a Glacial
nightmare as his deus ex machina, and entirely ignores the two
fundamental difficulties I have just pointed out.

It seems to me that a very much more simple explanation of the
phenomena we are discussing is available which needs no fantastic
postulates to support, but only an accurate induction from the known
facts. I would urge in answer to Dr. Brogger that what the Yoldia
and its companions require for their existence is not a uniform
depth of water in all latitudes where it lives, but a fairly uniform
temperature in the water. That temperature exists now not only in
the Arctic Circle but in the depths of the Atlantic and of the North
Sea, and needs no Glacial nightmare to create it in those latitudes.
It has not truly been proved to do so by a great many deep-sea
soundings, and itis an inevitable corollary from the interchange of
warm and cold water between the temperature of Arctic regions as
a result of natural laws of ocean circulation.

We all know the elementary example which has been so often
quoted, namely, the existence of living northern molluscs, not only
in the boreal latitudes of Christiania, but in the southern one of the
Mediterranean. These molluses do not occur there at the same depth

460 Sir H. H. Howorth—Geological History of the Baltic.

that they doin the more northern latitude regions, but very much
deeper. They occur in its abysmal depths, and we know quite
certainly that they occur there in very cold water. We also know
that the cold water in question is brought in by a deep current of cold
water from the Atlantic and has its complement in an outgoing upper
current which flows outwards. Not only so, we have an example

of the concurrent and contemporaneous effects of the presence of

a warm and an Arctic current side by side in Finmark and
the Lofoten Islands. In the former case the two zones of life

are separated by the North Cape, and in the latter by the islands just

named. In each case, within a few miles of each other, we have the
Yoldva fauna and the Tapes fauna living quite happily at the very

same time, the one supplied by an Arctic current and the other by the
Gulf Stream. Not only so, but off the north-west of the Lofoten

Islands, the Yoldva occurs living, not as Brégger demands, at a depth

of 10 to 80 fathoms, but of 60 to 100 fathoms, as we should expect.
with the change in the latitude. We naturally conclude that if
these conditions, but on a greater scale, were repeated in the latitude
of the Christiania Fjord by a sufficient depression of the sea bottom,

the Arctic water would necessarily find its way thither and the
Yoldva and their friends would thrive there, while at a higher level

quite close by, there would be living precisely the same fauna as

lives there at this moment. This is what is actually occurring on

some of the Norwegian fjords, where the great depth of water at

their lower end has induced a contrasted fauna between their upper
and lower reaches.

Now it is quite certain that the molluscs in the raised Tapes beds
of the Trondhjem and Christiania Fjords were living several hundred
feet below the present raised beach levels, or rather at a greater
depth still, for we must add probably 90 feet to the level of the
latter in order to secure them a sufficient submergence. Inasmuch
as the difference in the present level between the YVoldia beaches and
the Zapes beaches in the Christiania Fjord is very considerable, at
least 400 feet, it follows that the former must have been submerged
to a much greater depth than the latter, and in fact to-a depth
approximating to 800 or 1,000 feet. In that case the necessary
conditions for the life of Yoldia must have existed there in
the same way that they exist in the North Lofoten waters now,
only at a greater depth. This seems to me to be an exceedingly
simple explanation, and it is conclusive for those who do not believe
in transcendental causes. It further dispenses with all the see-saw
and rocking-horse machinery of earth movements against which Suess
protests so strongly, which are incompatible with these movements,
having been caused by lateral thrusts, as now generally held, and
which the glacial theory requires to explain the facts. This is not
all, we can produce direct evidence of a very interesting kind that
the explanation here maintained is the true one.

It is at all events a very remarkable fact that while the Yoldia
has become extinct in the Norwegian seas except in the north-west
corner of the Lofoten archipelago and perhaps the extreme north of
Finmark, the whole sea bottom along the coast of Norway is

Sir H. H. Howorth— Geological History of the Baltic. 461

covered with its dead shells, and it would seem almost certain that
this extinction of the shell was due to some uplift having interfered
with the Arctic water reaching that latitude in sufficient quantity.
Apart from this, the depth at which these dead shells are found (in
an area where the latest movements have been those of elevation)
shows that the Yoldia when living in Norway lived at a very much
greater depth than that suggested by Dr. Brogger as a necessity of
its life. :

There is another fact which is equally or still more impressive in
this behalf. We owe this notable piece of evidence to the researches
of Sars. He describes a famous reef near Drodbak, south of
Christiania, with an area of some 100 kilometres. This is in places
submerged to the depth of several fathoms, and in others it rises above
the sea at Barholmen, Kaholmen, etc., to a height of 30 metres above
the water-level. This reef is covered with a great deposit of the
dead coral Lophohelia (Oculina) prolifera, which is bush-shaped and
forms growths two feet in diameter and is accumulated in vast masses.
It cannot have been washed thither by the tide or a stream, for it is
firmly attached to the solid rock just as it grew. Although it only
occurs dead here, it is found living at vast depths in the deeper
fjords. Sars says at 150 to 200 fathoms, i.e. 900 to 1,200 feet more
or less. A.M. Norman found it in Bokkenfjord and Korsrjord at
a depth of 80 fathoms. Sars and Brogger both claim for its habitat
a very great depth. With it occur the very interesting shell Zima
excavata, together with Pecten vwitreus, Arca nodulosa, Cardium
minimum, Waldheimia cranium, Terebratella Spitsbergensis, and T. caput-
serpentis.,

This is a clear proof that when the coral was living the depth
of the Christiania Fjord at Drobak must have been quite great
enough to admit the Arctic current into that gulf, which then
extended as we have seen in a great inlet as far as the Malar Sea
and including the Cattegat, the peninsula of Vendsyssel, the great
lakes of Wettern and Wenern, of Mjosen and the Malar Sea, in
whose depths we have a number of still living relics of the same
cold conditions once prevailing there.

In conclusion, I wish, among other things, to emphasize in these
pages that the molluscan contents of the raised beaches completely
confirm the geological evidence of the very recent, continuous, and
cataclysmic uprise of Scandinavia and of the sea bottom round its
coasts, thus affording a complete parallel to the similar rise of the
other great peninsula of Greenland which I have described else-
‘where. One or two consequent results I have no space at
present to enlarge upon and can merely mention. One is that the
breaking of the Baltic breach created a complete gap in the history
of the fauna and flora of Scandinavia, which from that date to our
own can have altered very slightly and adventitiously ; and secondly
that the rise of such a mass of land in these high latitudes must have
considerably lowered the temperature and affected the internal
distribution of the plant and animal life in both of which respects
the evidence of biology completely concurs. I hope to enlarge on
these issues and to apply directly the arguments here used to Britain
on some other occasion.

462 Dr. H. Woodward—Carboniferous Arthropods.

III.—Nores on some Fossit ARTHROPODS FROM THE CARBONIFEROUS
Rocks or Cape Breton, Nova Scotra, RECEIVED From Dr. H. M.
Amt, M.A., F.G.8., F.R.S. (Can.).

By Henry Woopwarp, LL.D., F.R.S., F.G.S.

OME years ago I published, with the late Professor 1’. Rupert
Jones, F.R.S., a description of two small Limuloids referred to
the genus Bellinurus, sent me by my friend Dr. H. M. Ami (then of
the Canadian Geological Survey), who obtained them from the
Lower Carboniferous Marine Series on the Intercolonial Railway of
Canada, in Colchester County, Nova Scotia (Gror. Mae., 1899,
pp. 887-95, Pl. XV, Figs. 2 and 38), under the specific name. of
B. grandevus. Fig. 2 was collected from the sixth cutting east of
Riversdale Station and Fig. 3 from the third cutting east of Colnary
River.

Dr. Ami subsequently sent me a further collection of specimens
made by him in 1907, from the Carboniferous Series, Glace Bay
Mines, Cape Breton, Nova Scotia. Before describing these, how-
ever, I venture to give a few notes on the country whence they
were obtained, taken chiefly from Dr. Ami’s account of Nova Scotia.’

Nova Scotia, New Brunswick, and Prince Edward Island form a
group of provinces known as ‘‘the Maritime provinces”’, on the
eastern flank of the Dominion, and with Newfoundland represent
the most approximate land to our shores in North America.

«The peninsula of Nova Scotia, 268 miles in length, varying from
60 to 100 miles in width, forms a part of the ancient Acadia, being
connected by an isthmus with the Province of New Brunswick at
the head of the Bay of Fundy (well known for its high tides), its
main axis being from north-east to south-west, and its mountains,
with its appendage Cape Breton Island being, geologically, outliers
of the Appalachian system on the mainland to the south-west. The
northern limit of the Carboniferous system touches the Gulf of
St. Lawrence at Miscou Head, and extends in a broad band along
all the inner coast of Nova Scotia and into Cape Breton, and comes
out near Sydney upon the coast of the Atlantic, where the waves
wash the coal-seams on the sea-shore. Carboniferous rocks also
occur in the Magdalen Islands and at the south-western point of
Newfoundland, where a seam of coal 8 feet thick crops out near the
shore.

The Island of Cape Breton is really a continuation of Nova Scotia,
from which it is ouly separated by the Strait of Canso; it is
108 miles long, and contains the important coal-field of Sydney,
which extends along the Atlantic shore for 32 miles and covers an
area of over 250 square miles. Thirty-four seams occur in this
section, but only a few of them have been worked.

Pictou Coal-field, situated on Northumberland Strait, has the
finest harbour on the whole north coast of the province. Here the

1 Stanford’s Compendium of Geography and Travel (new issue), 1915,
North America, vol. i, Canada and Newfoundland; edited by Henry Ami,
M.A., D.Sc., F.G.S., F.R.G.S. F.R.S. (Can.); S8vo, 2nd ed. revised,
pp. xxviii + 1070.

Dr. H. Woodward—Carboniferous Arthropods. 463

largest vessels resort to ship coal from the adjacent mines. The
field is 85 square miles in extent, and is remarkable for the great
thickness of its seams. In one section the main seam is 34 ft. 7 in.,
and what is known as the deep seam is 22 ft. 1] in. thick. Other
seams range from 12 feet, 11 feet, 10 feet, 5 ft. 7 in., 3 ft. 3 in.; in
all 107 ft. 10 in. of coal have been recorded in this area.

The Carboniferous formation extends from the high land of
Cape George .westward along the whole coast of the peninsula
bordering Northumberland Strait, and across the country to Chignecto
Bay and the Minas Basin, at the head of the Bay of Fundy,
occupying Cumberland County and the greater part of Pictou,
Colchester, and King’s Counties. This forms the Cumberland Coal-
field and has an area of 430 square miles, worked chiefly at Springhill,
where eight seams occur with an aggregate thickness of 52ft. 7 in.
of coal. Mines have, however, been opened at several other places,
as at River Herbert, at Macdan, and at Jogeins, whose port and rail-
head is at Amherst.

At the Joggins, on the shore of Chignecto Channel, at the head of
the Bay of Fundy, is a unique natural exposure of @ continuous section
of Middle and Upper Carboniferous strata, which gave Sir William
Logan an actual measurement of 14,570 feet. It is a classic region
for geologists, and Sir Charles Lyell, who examined it in 1842, and
in 1845, and lastly in 1852, pronounced it to be the finest example in
the world of a natural exposure of uninterrupted coal-measures in
a continuous section 10 miles long.

The beds, says Lyell,’ are all seen dipping the same way, their
average inclination being at an angle of 24° S.S.W., the vertical
height of the cliffs being upwards of 300 feet. He observed seventeen
trees in an upright position, or, to speak more correctly, at right
angles to the planes of stratification; he counted nineteen seams of
coal, varying in thickness from 2 inches to 4 feet. At low tide
a fine horizontal section of the same beds is exposed to view on the
beach. The thickness of the beds alluded to is about 2,500 feet, the
erect trees consisting chiefly of large Sigillarie, occurring at ten
distinct levels, one above the other; but Sir William Logan, who
afterwards made a more detailed survey of the same line of cliffs,
found erect trees at seventeen levels, extending through a vertical
thickness of 4,515 feet of strata, everywhere devoid of marine

‘organic remains. The usual height of the buried trees seen by him
was from 6 to 8 feet; but one trunk was about 25 feet high and
4 feet in diameter, with a considerable bulge at the base. In no
instance could he detect any trunk intersecting a layer of coal,
however thin; and most of the trees terminated downwards in seams
of coal. Some few only were based in clay and shale; none of them,
except Calamites, insandstone. The erect trees, therefore, appeared
in general to have grown on beds of coal. In the under-clays
Stigmarie (the roots of the Sigillaria) abound.

In 1852 Sir William Dawson and Lyell made a detailed examina-
tion of one portion of the strata, 1,400 feet thick, where the coal-
seams are most frequent, and found evidence of root-bearing soils at

1 Elements of Geology, 1865, 6th ed., p. 482.

464 Dr. H. Woodward—Carboniferous Arthropods.

sixty-eight different levels. Like the seams of coal which often
cover them, these root-beds, or old sols, are at present the most
destructible masses in the whole cliff, the sandstones and laminated
shales being harder and more capable of resisting the action of the
waves and the weather. Originally the reverse was doubtless true,
for in the existing delta of the Mississippi those clays in which the
innumerable roots of the deciduous cypress and other swamp-trees
ramify in all directions are seen to withstand far more effectually
the undermining power of the river, or of the sea at the base of the
delta, than do beds of loose sand or layers of mud not supporting
trees.

As regards the fossil plants (of which Sir William Dawson records
over 150 species in the Coal-measures of the South Joggins),' they
belong to the same genera, and most of them to the same species, as
those met with in the distant coal-fields of Europe. Many of the
still erect trunks of Svgzlaria and Lepidodendron had their interiors
filled up with layers of sandstone, in which Lyell frequently observed
fern-leaves, and sometimes fragments of Stegmaria, which had
evidently entered together with sediment after the trunk had
decayed and become hollow, while still standing under water.

When the Carboniferous forests sank below high-water mark
a species of Spirorbis or Serpula attached itself to the outside of the
‘stumps and stems of the erect trees, adhering occasionally even to
the interior of the bark—another proof that the process of envelop-
ment was very gradual. These hollow upright trees, covered with
innumerable marine annelids, resemble a ‘‘cane-brake’’, as it is
commonly called, consisting of tall reeds of Arundinarva macrosperma,
which Lyell saw in 1846, at the Balize, or extremity of the delta of
the Mississippi. . Although these reeds are freshwater plants they
were covered with Balani, having been killed by an incursion of
salt water over an extent of many acres, where the sea had for a
season usurped a space previously gained from it by the river. Yet
the dead reeds, in spite of this change, remained standing in the
soft mud, showing how easily the Sigillarie and Lepidodendron,
hollow as they were but supported by strong roots, may have
resisted for some time an incursion of the sea.

The investigation of the organisms preserved in the interior of
these hollow trunks of Szgillarie, at the Joggins Coal-measures, by
Sir William Dawson, during many years, has resulted in the further
discovery of quite a number of new and very interesting forms of
terrestrial animals belonging to the Coal period.

Of these we may mention the remains of some small Amphibian
reptiles referred to Dendrerpeton Acadianum and Hylonomus Lyell,
Dawson. To these have been added Baphetes planiceps ; numerous
insect remains, and a atone Xylobius sigillaria ; | an air-breathing
snail, Pupa vetusta, eben

' Acadian Geology: The Geological Structure, Organic Remains, and
Mineral Resources of Nova Scotia, New Brunswick, and Prince Hdward
Island, by Sir Wm: Dawson, 8vo, 1868, pp. 694.

aes Air-breathing Animals of the Paleozoic Rocks in Canada,’’ by Sir Wm.
Dawson, C.M.G., F.R.S.: Trans. Roy. Soc. Canada, 1894.

Dr, H, Woodward—Carboniferous Arthropods. 465

Bivalve mollusca are extremely abundant in certain shale beds of
the Coal-measures, and many have been described and figured by
Sir Wm. Dawson, Dr. Wheelton Hind, and others.’

Fic. 1.—Anthracomya arenacea, Dawson. 1%. Found on the same slab
with Huproops Annie, H. Woodw. From Donkin Pit, No. 6. Coal-
measures : Glace Bay Mines, Cape Breton, Nova Scotia.

The specimens of Limuloid Arthropods already described by me
from Nova Scotia in this Macazinr (for September, 1899) were
referred to the genus Bellinurus ; those about to be noticed were also
obtained by Dr. Ami, but from the northern extremity of the province
at Glace Bay Mines in the Islarid of Cape Breton, and are referred
to the genus Huproops. (See Text-figs. 2-4, pp. 466-7, infra.)

Order MEROSTOMATA, Dana, 1852.
Sub-order II. XIPHOSURA, Gronovan, 1764.
1. Genus Evrroors, Meek & Worthen, 1868, Geol. Surv. Illinois,
vol. ii, 1868.

SynonyMY.—Prestwichia (H. Woodward, 1867), having been preoccupied
by Lubbock in 1863 for a genus of HYMENOPTERA, Hwproops becomes the
type for the following species :—

Huproops Dane, Meek & Worthen, Geol. Sury. Illinois, vol. iii, 1868.
. (Prestwichia) anthrax, H. Woodw., Quart. Journ. Geol. Soe., vol. xxiii,

Peoe ple toe 2) SG.

. (Bellinurus) anthrax, Bailey, Ann. Mag. Nat. Hist., ser. II, vol. xi,

p. 113, 1863.

. Collettt, White, Fauna of Indiana Coal-measures, Geol. & Nat. Hist.,

pl. xxxix, fig. 2, 1883.

. longispina, Packard, American Naturalist, vol. xix, p. 292 (not figured),

1885.

by

E

H

#H

E. (Limulus) anthraz, Prestwich, Trans. Geol. Soc., ser. 1, vol. v, pl. xii,
figs. 1-4, 1840.

Hi. (Prestwichia) anthrax, Bolton, Trans. Manchester Geol. Soc., vol. xxxiv,
fig. 120, p. ix, 1915.

E. (Prestwichia) Birtwelli, H. Woodw., Grou. MAG., Vol. IX, p. 440, Pl. X,
Figs. 9, 10, 1872.

EL. (Prestwichia) Birtwell, H. Woodw., Pal. Soc. Mon., Merostomata, pt. vi,

p. 247, pl. xxxi, figs. 7a, b, 1878.

E. (Prestwichia) anthrax, H. Woodward, Pal. Soc. Mon., Merostomata, pt. v,

p. 244, pl. xxxi, fig. 6, 1878.

Euproops Amie, H. Woodw., sp. nov. (Text-figs. 2-4, pp. 466-7.)

The specimens referred to this species consist of an almost
complete example and two detached head-shields of a new species
of ‘‘king-crab”’, exposed on the surface of three slabs of black-grey
shale, associated with specimens of a bivalve mollusc, Anthracomya

1 See Quart. Journ. Geol. Soc., vol. 1, pl. xx, fig. 4, 1894 (W. Hind).
DECADE VI.—VOL. V.—NO. X. 30

466 Dr. H. Woodward—Carbonrferous Arthropods.

arenacea, Dawson (Text-fig. 1), fragments of plant-remains, and some
traces of fish-scales.

Like the type of the genus (see supra, p. 465) in Kuproops Ama, the
head-shield is remarkable by reason of its narrowness from back to
front, and the extreme lateral expansion of its cheek-spines, which
curve upwards and outwards from the posterior border of the head-
shield towards the middle of the cheek before curving downwards to:
their slender extremities, forming an are of about 55 mm. measured
around the front border of the shield, and 36 mm. along the chord
from the extreme points of the cheek-spines, or more than three
times as wide as the head-shield is long. ‘The frontal border is
narrow and slightly flattened, and the frontal doublure is less
strongly marked.

Fic. 2.—EHuproops Ania, H. Woodw., sp. nov. Xx 1%. (The telson is
restored.) Donkin Pit, No. 6. Coal-measures: Glace Bay Mines, Cape
Breton, Nova Scotia.

The posterior border of the head where it unites with the
thoracetron is 14 mm. broad, but it widens to 29 mm. (including
the genal border). The glabella, which is slightly raised, is 10 mm.
wide at the cervical border, but slightly widens across the line of the
orbits, which are only obscurely to be determined, and is faintly
circumscribed by a roundly protuberant rim, within which the
glabella forms into a double arch in front, the two arches uniting
in a V-shaped backwardly directed ridge in the central line, behind
which are three small median lobes marked off by transverse furrows,
the hindmost resting on the cervical furrow and the front one
extending up to the V-shaped point of the axial ridge. The basis
of the glabella ridges gives rise to two backwardly directed slender
spines, each 9 mm. in length (these are broken off in Fig. 2,
otherwise the most complete specimen, but are seen in the detached
head-shields, Figs. 8 and 4). The thoracetron articulates along its
anterior border with the posterior margin of the head-shield, which
is roundly elevated and cordiform in outline, being 11 mm. broad
anteriorly, 16mm. across at its widest part, and about 25 mm. to the
extremity of its lateral marginal spines. The axial division of the
cephalon, 5 mm. in width, is continued down the centre of the thora-
cetron, diminishing gradually to about half that width posteriorly.

Dr, H. Woodward—Carboniferous Arthropods. 467

The longitudinal furrows of the axis serve to maintain the trilobed
character of the whole body. The thoracetron consists of six nearly
equal, coalesced segments (the ridge and furrow of each are marked
on the central lobe) curving backwards to the margin, and bordered
by a stout ridge, which in each segment terminates in a prominent
marginal spine (of which there are seven, the seventh forming
a part of the rudimentary abdomen); the spines are united to each
other by a flat narrow-scalloped border of the shield. The extremity
of the axis, composed of two or more coalesced segments and together
with the telson or caudal spine (wanting in this specimen), form the
rudimentary abdomen: (the telson or tail-spine being absent can only
be vaguely estimated from other specimens). here are indications
of tubercles along the axial lobe, the base of the largest of which is
seen near the termination of the axis over the articulation for the
telson.

BG SeSH axle Fie. 4: x 18.

Fies. 3 and 4.—Two detached head-shields of Huproops Amie, H. Woodw.,
showing long post-cephalic spines from the genal border of the head-shield.
From Caledonia Pit, No. 4: Glace Bay Mines, Cape Breton (H. M. Ami,
1907).

Compared with the type of Huproops (EL. Dane, Meek & Worthen)
the head-shield of #. Amie is deeper from back to front, the free-
cheek spines are more laterally divergent and more hollowed out
upon their inner posterior border; the axis is broader than in the
type, in which the margin of the glabella is somewhat narrower
and the eyes are said to be more anteriorly placed; in £. Amie
the posterior border of the glabella, which is rounded, terminates in
a pair of slender spines three times as long as those of the type
(#. Dane). The thoracetron in #. Amie is roundly cordiform, and
the scalloped marginal border is more definitely separated from it.
[As Dr. Meek’s specimen is mainly known by his admirable restoration
a strict comparison with less perfect materials leaves some points
rather doubtful. |

I dedicate this species to its discoverer, my friend Dr. Henry M.
Ami, who has devoted many years to the study of Acadian geology.

468 Dr. H. Woodward—Carboniferows Arthropods.

2. Nore on Kuproors (Prestwicuia) Brrrwerur, H. Woodw.
Prestwichia Birtwelli, H. Woodward, GEou. MaG., Vol. IX, p. 440, Pl. X,
Figs. 9, 10, 1872.
P. Birtwellr, H. Woodward, Pal. Soc. Mon., Merostomata, pt. v, pl. xxxi,
figs. 7a, b, c, p. 247, 1878.

After careful reconsideration of this species I have come to the
conclusion that the nodules in which these two specimens were
enclosed contained only the central portion of the body-shields, and
that the flat marginal scalloped borders, with their spines, and telson
were not preserved as they extended beyond the hard central con-
cretion into the softer external concentric layers of clay (as frequently
observed by Dr. Moysey and myself in the clay-ironstone nodules at
Shipley, near Ilkeston, Derby, and those also of Rochdale, Lancashire,
and Coalbrookdale, Shropshire), and so were not preserved.

The general form of the raised rounded central portion of the body-
shield resembles more that of Huproops than it does Prestwichianella.
Assuming the margin to have been furnished with a scolloped border
and the segments to have terminated in marginal spines upon the
border of the thoracetron, the resemblance to Huproops Dane,
FE. anthrax, and #. Amie would have been complete.

Formation and Locality.—Coal-measures: Cornfield Pit, south bank
of the River Calder, Padiham, Lancashire.

3. Notre on THE GENUS PRestwicHia, H. Woodw., 1866.

In reference to the genus Prestwichia I had for some time been
doubtful as to the advisability of retaining the species named
P. anthrax and P. rotundata under the same genus. The investigation
of this matter led to the discovery [to which my attention was
obligingly drawn by my friend Mr. Charles Davies Sherborn, of the
British Museum (Natural History) ] of a note which had appeared in
the American Geologist for 1905, p. 380, by Mr. T. D. A. Cockerell, of
the University of Colorado, U.S., that the name Prestwrchia had been
preoccupied for a genus of Hymenoprera by Lubbock in 1863, and
suggesting the propriety of transferring the species so named to
Messrs. Meek & Worthen’s genus ae oops, 1868. The specimen
here referred to was first described in 1865 by Meek & Worthen
under the name of Belinurus Dane; later on Mr. Meek assigned his
specimen to a new genus between Belinurus and Prestwichia, for
which he oaapeen the name Huproops, in allusion to the anterior
position of its eyes.’

But although this form, like Prestwichia, has the segments of the
thoracetron anchylosed, Euproops differs from it in the “quadraneular
form of the glabella, and the eyes being situated forward on its
anterior lateral angles, while in Prestwichia they are borne upon
the lateral margins; the genal border must therefore be considered
equivalent to the orbital suture, or (most probably) coalesced with it.?

1 F. B. Meek, Amer. Journ. Sci. & Arts, May, 1867. See also GEOL. MaG.,
July, 1867, p. 320, and Geol. Rept. by Meek & Worthen, Survey of Illinois
(Paleontology), vol. iii, 1868.

2 In many of the Trilobita the eye-suture and the axial line of the glabella
are close together; in young stages of the living American Limulus the axial

Dr. H. Woodward—Carboniferous Arthropods, 469

4, PRESTWICHIANELLA, gen. noy., 1918.

Prestwichia, H. Woodw., November 21, 1866.
P. rotundata, H. Woodw., Quart. Journ. Geol. Soc., vol. xxili, p. 32, pl. i,
fic. 2, 1866.
Limulus rotundus, Prestwich, Trans. Geol. Soc., ser. U, vol. v, pl. xli,
fie. 5, 1840.
Seeing that the name of Prestwichia, H. Woodw., was preoccupied
by Lubbock in 1863, I now propose to substitute, for the species
P. rotundata, the new generic name of

Prestwichianella, H. Woodw., gen. nov.!

Character amended.-—UHead-shield semicircular. The genal borders
and frontal margin are broad and smooth, and curved roundly on
each side towards the thoracetron and ending in moderately broad
lateral genal spines; the glabella is divided along the centre by the
axial furrow, and by two other slightly diverging parallel lines on
either of the axes, reaching nearly half-way to the frontal border,
where they are arcaded, forming a rounded raised confluent line in
front of the glabella. ‘The circular line seen outside the border of
the glabella may indicate the impression of the line of the broad
incurved under-margin of the head-shield.

The thoracico-abdominal series of segments are apparently united
together into one buckler, as seen in the larval stages of living
Limulus (see H. Woodward, Mon. Pal. Soc., Merostomata, pt. v,
pl. xxxi, figs. 10-12, 1878). Central axis of body-segments
narrow; abdomen rudimentary and coalesced with the hindmost
thoracic segment, most probably bearing a short telson or tail spine.
The broad membranous margin of the thoracetron extends nearly to
the extremities of the seven strongly marked spines. Five short
spines mark the posterior margin of the head-shield, and some small
tubercles along the centre of the posterior axis with a more prominent
spine near the base of the telson.

5. Nore on Betiryurus TRECHMANNI, A NEW SPECIES OF LIMULOID
ARTHROPOD FROM THE DurRHAM COAL-FIELD.

I have been favoured by Mr. C. T. Trechmann, of Castle Eden,
Durham, with the loan of a small specimen of a fossil ‘‘ king-crab”’,
which he lately collected in the highest Coal-measures of the Durham
Coal-field at Claxheugh on the Wear, near Sunderland. The beds
are in the zone of Anthracomya Phillipsii, not generally known to
occur in the Durham area, and as they will be shortly described by
Dr. Trechmann he kindly permits me to notice this find in advance.

In 1866 I communicated a paper to the Geological Society, ‘‘ On
some points in the Structure of the Xiphosura, having reference to

line and the orbital suture are quite distinct and apart from each other (see
Mon. Merostomata, pt. v, pl. xxxili, fig. 10, after Packard; fig. 12, after
Dohrn’s ‘* Trilobitenstadium’’). In the adult living Limulus the compound
_ eyes occupy the lateral border of the glabella.

1 P. anthrax and P. Birtwelli are now referred to Euproops.

* See description in H. Woodward’s Monograph on the Merostomata, Pal.
Soc. vol., 1878, pt. v, pp. 244-7, pl. xxxi, fig. 5.

470 Dr. H. Woodward —Carboniferous Arthropods.

their relationship with the Kurypteride”’: Quart. Journ. Geol. Soc.,
vol. xxill, pls. 1 andi, p. 32, 1867; and again, in my Monograph on the
Order Merostomata, Pal. Soc., pt. v, 1878, sub-order Xiphosura,
pp. 236-48, I discussed the arrangement of the several genera of
these Palzozoic forms of Arthropoda and proposed to divide the
Coal-measure species into two genera :—

(A) Those having movable thoracic segments and anchylosed
abdominal ones, under the genus Bellinurus (with 8 species, 1918).

(B) Those in which all the post-cephalic segments are coalesced
under the genus Prestwichia. The name being preoccupied, it has
now been found necessary to subdivide this latter group into two
genera, namely: (1) Prestwichianella, with 1 species; (2) Huproops,
with 6 species.

In Section A, Bellinurus, Konig, the earliest records of this genus
in which intelligible figures are given are: by Mr. Charles Konig,
Keeper of Geology and Minerals in the British Museum in 1820
(Icones Foss. Sect., pl. xviii, fig. 280), and later, in 1836, by
Buckland, in his Bridgewater Treatise, 1, p. 396; 11, p. 77, pl. xlv,
fig. 3; Mr. Prestwich, in 1840, Trans. Geol. Soc., ser. i, vol. v,
p. 491, pl. xl, fig. 8; H. Woodward, 1866, Trans. Glasgow Geol.
Soc., p. 247, pl. iu, fig. 10, and Pal. Soc. Mon., Merostomata
(Xiphosura), pt. v, 1878, p.-236, pl. xxxi, figs. 3a, 6, c, and 4.

Genus Brtiryurvs, Konig, 1820.
The species included under this genus are :—

Bellinurus bellulus, Kénig, 1820, Icones Foss. Sect.

. arcuatus, Baily, Ann. Mag. Nat. Hist., ser. 11, vol. xi, p. 112, 1863.

. regine, Baily, Ann. Mag. Nat. Hist., ser. 111, vol. xi, p. 107, pl. v, 1863.
kiltorkensis, Baily, Brit. Assoc. Rep., p. 75, 1869.

. Kemigianus, H. Woodw., GEOL. MAG., p. 439, Pl. X, Fig. 8, 1872.

. grandevus, Jones & Woodw., GEOL. MAG., 1899.

. lunatus, Parker, Lancashire Naturalist, 1907, p. 44.

. Baldwini, H. Woodw., GEoL. MAG., 1907, p. 540, Fig. 1.

. longicaudatus, H. Woodw., GEOL. MAG., 1907, p. 541, Fig. 2.

by by by bs by by by by

Betiinvrvs Trecumanni, H. Woodw., sp. nov.

Specific Characters. — Head-shield semicircular, being 9mm. in
breadth and 4mm. in length, the genal spines moderately long,
24mm. in length, directed outwards (the extremity is only preserved
on one side); breadth of glabella 24mm., the length is not easily
determined but probably about two-thirds that of the head-shield,
and there is a faint trace of the arched axis. ‘he frontal border of
the head-shield is distinctly marked and the centre is roundly
elevated; the eyes are not distinct; the posterior border between
the spines is fairly straight and measures 7}mm. The axis of the
thoracetron agrees with that of the glabella in breadth (viz. 2} mm.),
only very slightly diminishing towards the telson; its length is
4mm. There are six free post-cephalic segments, which are markedly
trilobed, directed slightly backwards, ending along the lateral margin
in stout recurved spines; the pleurz of these free segments diminish
rapidly towards the extremity of the thoracetron. There is a small
coalesced abdominal portion bearing a tubercle above the insertion

W. D. Varney—* Coal-balls,’ Ambergate, Derbyshire, 471

of the stout tail-spine, which is 1mm. in breadth, but is only
impertectly preserved (length unknown).

There seems to be good evidence that the division (A) of Paleozoic
‘‘king-crabs”’ represented in the Coal-measures by the genus
Bellinurus contains the oldest form of the Xiphosura, which take
precedence, in time, over those with anchylosed segments referred to
the division (B) represented by the genera Prestwichianella and
Euproops, as evidenced by their precursor, Weolimulus falcatus,
H. Woodward,! 1868.

This earliest known form from the Upper Silurian appears to have
had ail its segments free and unanchylosed, and the later form
Bellinurus kiltorkensis, Baily, from the Old Red Sandstone, probably
represents the same genus as is met with in the Coal-measures with
free thoracic, and most of them had anchylosed post-thoracic somites.

Fic. 5.—Bellmurus Trechmanni, H. Woodw., sp. nov. x 4. Upper Coal-
measures: Claxheugh on the Wear, Sunderland.

The entire series of species of Gellinurus vary little in their general
characters. ‘They are all of small size and possessed a long caudal
spine and rather marked triangular thoracetron.

The specific characters of the Durham specimen are the obviously
shorter and outwardly directed cheek-spines, and the broader and
more parallel-sided axis of the thoracetron, which is proportionately
larger than in the other species of this genus.

T dedicate this species, which is the ‘first that has been discovered
in this great coal-field, to Mr. C. T. Trechmann, whose admirable
contributions to the paleontology of New Zealand have already
appeared in the pages of the GroLocican Magazine and elsewhere.

ITV.—On vHe Occurrence oF ‘‘CoAL-BALLS’? NEAR AMBERGATE,
DrRBYSHIRE.
By W. D. VARNEY, B.Sc., University College, Nottingham.
N the brick-pit cut into the Lower Coal-measures at Bullbridge,
near Ambergate, the Alton Coal is exposed, immediately over-
lain by a marine shale roof, containing large nodules (bullions) and
marine fossils.

1 See Grou. MaG., Pl. I, Fig. 1, and Mon. Pal. Soc., 1878, pt. v, Xiphosura,
pp. 233-5, woodeut, and pl. xxxi, fig. 8.

472 W. D. Varney— Coal-balls,” Ambergate, Derbyshire.

This succession is similar to that occurring at Shore and other
well-known localities in Lancashire, where the Bullion or Upper-
Foot Mine contains numerous ‘‘ coal-balls’’.

No such concretions have been found and recorded from Derby-
shire, but the Alton Coal in the above-named exposure was found to
contain large nodules of iron pyrites. Some of these have centres
composed of calcite or calcareous material, suggesting that these
nodules were originally wholly calcareous.

One of these specimens, on being sectioned, was found to have a
centre of calcite containing a Stigmarian rootlet, with the xylem (a
fairly well preserved surrounded by the cortex (6), which, though
in a poor state of preservation, is still quite recognizable. Other
parts of the section contained plant tissue badly preserved, and
partly obscured by pyrites. Pyritization seems to have taken place
along lines of tissue running through the calcite groundmass as
seen at (d) and (c) in the diagram and in other parts of the slide.

Section of nodule showing plant-tissues (somewhat diagrammatic). a, xylem of
Stigmarian rootlet; 6, cortex; c, d, other tissue, partly hidden by pyrites (e).

At Bullbridge the Alton Coal is streaked with pyrites, which fills
cracks and joints, and the thin veins often join on to the nodules of
the same material. Hence the pyrites was deposited after the
formation of the seam and its nodules. This fact, and the features
of the nodule section described, show that the pyrites is secondary,
and that the calcite and its petrified plant tissue were deposited
before the pyrites, which has replaced the former and largely
obliterated the vegetable tissue in so doing. In other words the
nodules were true ‘‘coal-balls”, now partly or wholly replaced by
iron pyrites.

Hence the Alton Coal of Derbyshire contains nodules with petri-
factions, though they are mostly altered to iron pyrites. Thus the
seam shows a striking resemblance to the Bullion Seam of Lancashire,

as described by Miss Stopes and D. M.S. Watson.’

‘ **On the Present Distribution and Origin of Coal-balls’’: Proc. Roy. Soc.,
VOIMNEe spans:

Reviews—Geological Survey of Great Britain. 473

A rough analysis of the specimen sectioned showed that it con-
tained, in addition to iron pyrites, calcium and magnesium carbonates
and calcium sulphate, the last-named being present in sufficient
quantity to form a thick efflorescence when the nodule had been kept
for some time. ‘his calcium sulphate is confined to the coal and its
marine roof, where it is also abundant,' and to these two beds only,
so that its occurrence seems intimately connected with the latter bed.

A new locality, therefore, can be cited for the occurrence of
‘‘coal-balls”’ or their equivalents, namely, the Alton Coal of Derby-
shire, particularly near Ambergate, under conditions which help to
confirm the theories enunciated by Professor Stopes and D. M.S.
Watson,” namely, that in whatever coal tissue-bearing nodules occur,
that coal is overlain by a roof of marine origin, and that the forma-
tion. of these nodules was contemporaneous with that of the
surrounding coal.

REV LewS-

I.—Summary or Proeress or THE GeroLtogicaL SURVEY oF GREAT
Britain For 1917. 55 pp. London, 1918. Price 2s.

i is a noteworthy sign of the times that this summary of the
year’s work of the Geological Survey deals almost exclusively
with matters of practical and economic interest. The depleted
staff has given evidence of great activity, and an immense amount
of useful information has been collected, with the assistance of
certain specialists who were temporarily attached to the Survey.
The most important work carried out was an investigation into the
reserves of iron-ore still existing in Great Britain. Every possible
iron-field seems to have been very thoroughly examined, and it is
estimated that the grand total of ores of all kinds amounts to no less
than 11,311,000,000 tons. However, much of this is of very low
grade and unlikely to be worked for some time to come.

The subject of refractories has also engaged much attention and
a comprehensive memoir on the subject is in course of publication.
The increased demand for tungsten ores has brought about important
developments in Cornwall and Devon and new lodes have been
reported on. A ‘special examination was also made of Scottish
pegmatite dykes as possible sources of potash felspar for pottery,
enamel, and other purposes. A magnetic survey of certain parts of
England was undertaken with the object of ascertaining whether
certain observed disturbances of the magnetic needle were due to
concealed masses of iron-ore ; a report on the subject is in prepara-
tion. The proposal to construct a ship-canal across Scotland has
necessitated investigation of the depth of drift and other superficial
deposits along the proposed lines, with interesting results. Good
progress has also been made with the publication of memoirs on the
Scottish coal-fields.

1 R. D. Vernon, Grou. MAG., 1909, p. 289.
{ ibides pe lee

ATS Reviews—British Museum Annual Report.

Three appendices contain accounts of the results of deep borings
at Market Weighton, Newark, and Hitchin respectively. The first
of these shows that the Trias and Permian do not thin away north
of the Humber, as was hoped; the boring was stopped in Lower
Permian Limestone at 3,100 feet from the surface. The boring at
Kelham, near Newark, reached the Coal-measures at 1,401 feet, and
penetrated to the Carboniferous Limestone Shales. Only 148 feet
of strata can be assigned to the Millstone Grit, hence the boring
probably passed through at least one fault. The Hitchin boring
appears to indicate a thickness of 250 feet of drift near the western
margin of the drift-filled channel already known to exist in that
neighbourhood.

R. H.R.

II. — British Museum Rerorn, 1917. Published by H.M.
Stationery Office, London, 1917. Price 6d.
W\HIS report as usual contains a large amount of interesting
information as to the progress of the various departments of
the British Museum, together with the accounts of the special trust
funds. The number of visitors at Bloomsbury naturally shows
a great falling off, since for ten months out of the twelve the
galleries were closed to the public. At South Kensington most of
the galleries remained open during the year 1916 and the number of
visitors was nearly as large as usual, amounting to 402,673. The
staff carried out for the Government a large number of investigations
on subjects directly connected with the War, as well as other special
work of a more normal kind, and various topical exhibits have been
arranged. The number of new acquisitions is somewhat smaller
than usual, as might be expected, but the general routine work of
the Museum has suffered little or no interruption, and the publica-
tion of serial reports has been continued. A large number of
valuable fossils have been presented to the Department of Geology,
of which the most important are perhaps those comprised in the
Hamling Collection from Devonshire, while the Department of
Mineralogy has also acquired many specimens of interest, including
several meteorites from various falls not hitherto represented in the
collection.

Ill.—Ter Work or Locat Socrerres anp Museums.

iP spite of the adverse conditions of the present time as regards
scientific work on subjects not directly connected with the
War, it is gratifying to note that many local societies seem to
pursue the even tenour of their way with little visible disturbance.
For example, the fifty-first Report of the Rugby School Natural
History Society for the year 1917 contains evidence of great
keenness and enthusiasm among the members, who are carrying out
useful observational work of several kinds, zoological, botanical,
geological, and meteorological. The section of physics and chemistry
has also been active, and the report contains reprints of two interesting

Reviews— Materials required in Glass-making. 475

papers by members, on the fixation of atmospheric nitrogen and on
saccharine respectively.

The first part of the third volume of the Hastings and Hast Sussex
Naturalist, the organ of the Hastings and St. Leonards Natural
History Society, also shows evidence of much activity on the part of
that Society. It contains two papers of geological interest. The
first of these, by Mr. Anthony Belt, is entitled ‘‘ Prehistoric
Hastings’’, and comprises a very full account of the geological
history of that interesting district, from the Wealden to the Roman
occupation. Most space is devoted to the later phases, and special
attention is paid to the history and development of man, as is only
natural in a district so near to the home of Hoanthropus Dawsont.
Another valuable contribution is a paper on the Brighton Rubble-
Drift formation, by Mr. E. A. Martin. This, though short, gives
a very good description of this peculiar and interesting formation, —
illustrated by phot graphs.

The annual report of the Norwich Castle Museum for 1917 shows
that the Museum was the centre for the dissemination of much
useful information, and the fact that it was visited by no less than
132,751 persons shows that it has succeeded in fostering a widespread
interest in historical and scientific subjects.

TV.—Barririso Suppries or Porash FEnsparR, CONSIDERED FROM THE
Guass-mMakine Potnr or View. By Professor P. G. H. Boswutt,
D.Sc., F.G.8. Trans. Soc. Glass Technology, vol. ii, pp. 35-71,
with 1 plate and 4 figures. 1918.

OTASH-FELSPAR for use in the pottery and glass industries

should satisfy the following requirements :—

1. High content of potash, if possible more than 10 per cent and
certainly not less than 8 per cent.

-2. Low content of soda; preferably none and certainly not more
than 2 per cent.

3. Low content of quartz, not more than 5 per cent for the best
pottery, and not in excess of 20 per cent for inferior pottery. In
glass-making the quartz does no harm, but it can be bought at
a lower rate than felspar.

4. The amount of iron oxide should be small, and in the best
pegmatites the percentage falls below 0:1.

5. Lime should not exceed 0°5 per cent.

6. The rock must be fresh, or there will be a considerable loss of
potash owing to kaolinization of the felspars.

It may be mentioned that 13 and 9 per cent of potash correspond
respectively to 77 and 538 per cent of microcline or orthoclase, and
3 and 1 per cent of soda to 25 and 9 per cent of albite.

More or less workable deposits of potash-bearing felspar in the
form of pegmatites occur in many localities in the British Isles.
These are Tresayes, Trelavour Downs, Kernick, and Luxulyan in
Cornwall; in Sutherland, between Lochs Laxford and Inchard,
between Durness and Eireboll and near Overscaig, Strontiau

476 Reviews—Materials required in Glass-making.

(Argyllshire), Portsoy (Banff), and Monymusk (Aberdeenshire) ;
near Belleek, on the borders of co. Donegal and co. Fermanagh, in
-the Glenties area of co. Donegal, and the Bellmullet area of co.
Mayo.

Felspars of the best quality (grade 1) occur in Cornwall at
Tresayes, Kernick, and Trelavour, and in the neighbourhood of Belleek
in Ireland. These occurrences are all situated fairly near to road,
railway, and the sea, but the quantity in each case is limited.
Each area yields hand-picked material suitable for the best glass and
pottery work, showing from 10 to 13 per cent K,O, but none of
them can be worked on the large scale for the extraction of potash.

Round Rhiconich and near Durness in Sutherland, on Erris Head
near Bellmullet, and on the Gweebarra River in co. Donegal there are
millions of tons of pegmatite of grades 2 and 3. These, however,
would not yield more than 8 or 9 per cent of potash after hand-
picking, and are almost unworkable on account of their inaccessibility.
These large deposits might possibly be worked for the extraction of
their potash, but the operations would have to be conducted on very
efficient lines for such a project to be payable, the chief difficulty
being the shipping of the felspar, on account of the distance of the
deposits from available harbours.

The supplies of high-grade spar in the Cornish and Belleek areas

“might be sufficient for the requirements of our industry for a limited
dime, but not for any considerable period, owing to the small reserves
available. Certain felsites near Wicklow and Waterford and some
Cretaceous glauconitic sands have been suggested as sources of
potash, but unfortunately their potash content is in most cases much
too low and never sufficiently high to render them worth working.

The paper is furnished with numerous analyses of the felspars and
pegmatites, including some foreign as well as the British examples.
It represents a very considerable amount of work, since the author
has visited all the localities which he describes, some of which, being
situated in the wildest parts of north-west Scotland and the west of
Ireland, are very difficult of access.

Wie We

V.—Bnririsoh Resources oF Sanps anp Rocks usEp in Grass-maxine.!
By Professor P. G. H. Boswett. Second and complete edition.
pp. xi +170, with 10 plates and 13 figures in the text.
London: Longmans, Green & Co. 1918.

ye this second edition the author’s two earlier memoirs on British
glass sands are combined into one volume. A few parts have
been rewritten and some further information has been added, but
otherwise most of the matter is the same. The book in its present
form is a comprehensive survey, not only of British glass sands, but
of the more important foreign occurrences, and also of other deposits

essential to the glass industry, such as those of potash and alumina.

WE Wie

1 See also GEOL. MaG., March, 1918, p. 131.

Reviews— Western Australian Geology. ATT

VI.—Own tae Sprirrine or Coat Seams By Parvines oF Drirr.
Part 1: Spxrirs roar Reson. By P. F. Kenparzt. ‘Trans. Inst.
Min. Eng., vol. liv, p. 460, 1918.

(J\HE explanation of the splitting of coal-seams that has so long

done duty in text-books is unsatisfactory and often inapplicable
to actual instances, since it is frequently found that the upper
portion of the split seam is convex upwards while the lower portion
is horizontal. , Professor Kendall has made a careful study of split
seams in the Yorkshire coal-field, especially in the Silkstone or

Middleton Main and Haigh Moor seams at Whitwood, Ackton Hall,

Methley, and South Kirkby. The explanation put forward depends

on the well-known fact that peat on conversion to coal undergoes

a very great reduction in volume, here estimated at 20 to 1.

A trough-like wash-out in a bed of peat, filled with sand or mud,

would be much less compressed than the peat; the whole mass

would settle down in a ridge-like form with a thin layer of coal
above and below the sandstone or shale, the form of the mass thus
undergoing inversion in cross-section.

By mapping the known position of the edges of split seams it has
been found possible to trace out the courses of Carboniferous rivers
over distances of several miles, and the method of investigation
pursued seems likely to lead to results of great practical and
scientific interest.

Jaen Joly Dkk.

VII.—Some Prosiems or Western AustraLian Grotoay. Presidential
Address to the Royal Society of Western Australia, delivered on
July 11, 1916, by A. Gipp Marrtanp, F.G.S. pp. 34, with
38 figures. Perth, 1917.

le this presidential address the author deals chiefly with the
Nullagine formation. This series of rocks has a very wide

distribution in the state, and is composed chiefly of sandstones,
quartzites, conglomerates, dolomitic limestones and igneous rocks,
dolerite dykes and sills, with lavas and ashes at one horizon.
The series, the lower members of which are gold-bearing, rests
with a very marked unconformity on the underlying rocks, which are
everywhere metamorphosed and of pre-Cambrian age. The sequence
begins with a basal conglomerate, which is followed by an outbreak
of lavas and ashes, chiefly andesitic, but in places rhyolitic, which
appear to have been produced by fissure eruptions, as few volcanic
foci have been discovered. These rocks are followed by dolomitic
limestones, which are in turn overlaid by a sandy series with
hematite and magnetite, bearing quartzites or jaspers, having some-
times as much as 37 per cent of iron. The ferruginous bands are
thin and interbedded with light-coloured quartzites, so that a banded
rock is produced.

The dolerite sills are of very uniform composition and do not
seem to have undergone much metamorphism since their intrusion ;
they are accompanied in the more disturbed areas by quartz reefs
with gold and copper. The reservoir which supplied this igneous
material seems to have been situated about latitude 26° 8. There

-—

A78 Reviews—Canadian Geology.

are several points which require elucidation in connexion with this
formation ; firstly, the age is very uncertain, the rocks were affected
_by pre-Permo-Carboniferous folding and rest on crystalline schists;
H. P. Woodward thought they were Devonian, but this cannot be
proved in the absence of fossils. Again, it is not clear whether the
igneous rocks of the intrusive phase followed closely on those of the
volcanic phase or not. Finally, the ore-bearing rocks of Western
_ Australia are all more or less associated with the Nullagine formation,
but it is uncertain whether the mineralization was associated with
the pre-Cambrian mountain-building movements which produced the ©
metamorphism in the older rocks or whether it took place after the
deposition of the Nullagine formation.

Wo We

VIII.—An Exptoration oF rae Tazin anp Tarrson Rivers, Norta-
Wesr Turrtrories. By CuHartes Camsett. Geological Survey
of Canada, Memoir 84. pp. 111+ 124, with 18 plates and map.
Ottawa, 1916.

N the North-West of Canada there are still vast tracts of country

which are as yet unexplored; one of the largest of these

‘‘blocks’’ forms the subject of this communication. The region is

situated between the Great Slave Lake and Lake Athabasca; it is

part of the Laurentian plateau region and abounds in lakes, while its
rivers flow in irregular valleys which are rarely more than 100 feet
deep.

The oldest rocks, which occur now in isolated patches, are
‘‘a series of schists, quartzites, conglomerates, limestones, argillites,
and some volcanic rocks’’, which are grouped together under the
name of the Tazin Series. These are Archeean rocks, probably
Huronian in age. The Tazin Series is invaded by a great composite
batholith of gneisses and granites with some quartz diorites. ‘These
rocks, which occupy the greater part of the area, have a north and
south trend, corresponding more to the Cordilleran lines than to
those of Eastern Canada. At one place, at the north-east end of
Tazin Lake, there is a remnant of the Athabasca Sandstone, which
is a conglomeratic deposit of Keweenawan age, and probably of
terrestrial origin. After this rock there is a complete absence of
any deposit till those of the Pleistocene glaciation. The glaciation
in this region was very intense, as is shown by the rounded, grooved,
and striated character of the rocks, and by their fresh and un-
weathered condition. Glacial deposits, boulder-clay, moraines,
drumlins, and sand plains are found, but not in any great abundance,
the rock being mostly left bare of any surface deposit. The direction
of motion of the ice as shown by the striz seems to have been about
S. 62° W., while there is evidence of a later feebler glaciation with
a more northerly trend. The Tazin Series is cut by numerous quartz
veins which contain pyrites in places, and seem to offer some
prospects of valuable metalliferous deposits. The memoir contains
also a detailed account of the canoe routes followed by the author,
and is illustrated by many excellent photographs of the country.

W. H.W.

Correspondence—J. Wilfrid Jackson. 479

IX.—Frozen Mock ry 1HE Kionpixe Disrricr, Yuron Trrerrory,
Canapa. By J. B. Tyerenn, F.R:S:C. Trans. Roy. Soc.
Canada, ser. 111, vol. ix, pp. 89-46, with 3 plates, 1917.

‘W\HE valley floors of the Klondike District are the products of the

third cycle of erosion since the last continental uplift of the
region. In the Miocene period the Dome peneplain was produced by
the first cycle of erosion. In Pliocene times the valleys in which
the older White Channel gravels were deposited were carved out
during the second cycle of erosion, while the present valleys and
their alluvial gravels are connected with the third cycle, which lasted
till the end of the Pliocene period. During this time the climate
was temperate and the country was inhabited by a number of the
larger mammals, but at the beginning of the Glacial period different
conditions set in, and, though this region was not covered by an
ice-sheet, the soil was certainly frozen all the year round., In con-
sequence of this the alluvial gravels and the beds of the streams
became impervious to water and resistant to erosion. When,
therefore, the snow melted in the spring the water in the stream
channels brought down, instead of sand and gravel, only vegetable
debris from the hill-sides, which collected on the alluvial flats and
was held fast and preserved by the large growth of bog mosses.

In this way great thicknesses of this frozen bog or ‘‘muck”’ were

accumulated, varying from 2 to 40 feet and even 100 feet in the

narrower gulches, which have to be sunk through before the gold-
bearing gravels can be worked. ‘‘ Muck”? is also found in the form
of frozen bogs on the hill-sides, where it often contains layers of
clear ice, tilted at steep angles by the slipping of the bog. The

‘“muck’’? now forms the upper part of the valley deposits, which

shows that little or no gravel has been transported since the

beginning of the period of perennial frost, and that, therefore, the
valley gravels are all pre-Glacial in age.

CORRESPON DEHNCE.

ON TEREBRATULA GRAYI, DAVIDSON.

Sir,—In a former paper in this Magazine (Dec. VI, Vol. III,
pp. 21-6, 1916) I proposed the name Zhomsonia for the Terebratula
grayt of Davidson. This name, I find, has unfortunately been used
for Insecta on two previous occasions, viz. in 1879 and 1884, and,
therefore, cannot stand. In its place I now propose

CoptorHyris, gen. nov.

Coptothyris grayi has been placed in Waldheimia (now Magellania)
and in Dallina by various authors, on account of the loop having
reached the highest developmental stage in the Terebratellide; but
it is distinct from either of these genera on other grounds. The full
details of these differences are reserved for a future paper on the
cardinalia of the Dallinine in general. In this paper I hope to
show that the cardinalia (or hinge-processes of the dorsal valve) of
the sub-family Dallinine can be readily differentiated into, at least,

480 Correspondence—Dr, Wheelton Hind. |

three distinct types, each being represented by forms which have
attained the Dalliniform loop-stage of Beecher, viz. Coptothyris,
Macandrevia, and Dallina. These three genera are also characterized
by distinct types of beak characters, dental plates, ete. Thus three
evolutionary stocks can be clearly recognized, in each of which
Dalliniform loops have been attained by parallel evolution. There
appear to be other stocks present, but in these there is as yet no
evidence for the separate attainment of the Dalliniform loop.

The study of the hinge characters of the species of Dallinine
contained in my collection (comprising most of the known forms) has
revealed many interesting features which have an important bearing
upon the classification of both recent and fossil forms. For some of
these forms it will be necessary to create new genera.

J. Witrrip Jackson.

MANCHESTER MUSEUM.
September 4, 1918.

THE CANINIA-SHMINULA HORIZON OF PRODUCTUS
HUMEROSUS.

ou —I have just received my copy of the Q.J.G.S., containing
Mr. Parsons’ most excellent paper ‘‘On the Carboniferous Limestone
of the Leicester Coalfield’’. I want to ask him to reconsider the
question of the horizon of the beds containing Productus humerosus
(P. sublevis). Following Professor Sibly, who referred the Cauldon
Low (Staffs) Limestones to D,, he has not pointed out that
P. humerosus is an important zonal fossil both in Belgium and the
Clitheroe area, indicating a Caninia—Seminula horizon. Therefore,
one must pause to think before beds containing it are assigned to
a much higher zone. The paleontological evidence of the Cauldon
Low beds is strengthened by the presence in them of other members
ofthe C-S, fauna. Papillionaceous Chonetes, Bellerophon cornuarvetis,
and other members of that genus, and several large Gasteropods
which can be matched in Belgium and Clitheroe. I note that
Cyrtina septosa oceurs with P. humerosus. This, too, indicates the
lower zone.

Then, again, the barrenness of the beds and the absence of
LInthostrotion and a Dibunophyllum fauna are very noteworthy.
I have, no doubt, in my own mind that the Cauldon Low beds are
of Caninia age, and the whole question will be more fully discussed
in a forthcoming paper on the Clitheroe area.

Wueetton Hinp, M.D., B.S., F.R.C.S.

ON SERVICE.

September 7, 1918.

STRATIGRAPHICAL POSITION OF THE CORALLINE CRAG.
Mr. F. W. Harmer’s article in the September
Number, ‘‘ Stratigraphical Position of the Coralline Crag,” p. 410,
for Walton horizon read Oakley horizon= Poederlien, and for Oakley
horizon read Walton horizon = Scaldisien—the names Walton and
Oakley having been reversed.

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NEW SeRle6. DECADE WIL VOL. Vv.
No. XI.—_NOVEMBER, 1918.

I.—Tue Jron-Fretps or LorRarne.
By R. H. Rasta, M.A., F.G.S.

ECENT events have again called attention to the enormous
strategic and economic importance of the iron-fields of
Lorraine; on these much of the commercial prosperity of Germany
has been built up in the past, and on their possession her future as
an industrial nation largely depends. For many years the output of
iron-ore from the part of Lorraine under German control has been
immense: in 1912, German Lorraine produced approximately
20,000,000 tons, while the output of Luxemburg, which, for all
practical purposes, is German, was about 6,500,000 tons. In the
same year the French portion of the Lorraine iron-field yielded
17,300,000 tons, making a grand total for this area of 43,800,000
tons of ore. During the War the whole of the French productive
region has been occupied by the enemy, and there is no means of
ascertaining what has actually happened there, but certain
inferences can be drawn from published facts and on a basis of
probability.

First, however, it is necessary to consider briefly the geographical
distribution and geological structure of these regions. The Briey
plateau forms a somewhat elevated region extending from the
southern border of the Ardennes to a little south of Metz: it is
dissected by the valleys of several rivers, including the Moselle,
Orne, Fentsch, Algringen, and Meurthe. Geologically the plateau
is composed of Jurassic rocks, chiefly Lias and Dogger, and it is near
the boundary of these two series that the beds of iron-ore occur. By
German geologists they are referred to the Dogger, by French
authorities mostly to the Lias. According to Van Werveke they
belong to the zone of Ammonites Murchisone.

The Briey field is nearly 40 miles long, with a width of about
15 miles, within which the ore is believed to be payable; south of
it comes a barren region extending for some 15 miles and then the
Nancy field, which is about 13 miles long. ‘The Lorraine plateau as
a whole is divided by rivers and other natural boundaries into
several subsidiary regions, while the basins of Longwy and Crusnes
are of considerable importance. In the French portion of the Briey
field the chief subdivisions recognized are those of Orne, Landres,
and Tucquegnieux.

The general geological structure is very simple, as the whole
series dips gently to the west. The iron-bearing beds outcrop on
the eastern side of the plateau a few miles east of the frontier and in
the south of Luxemburg, hence they naturally become deeper and

DECADE VI.—VOL. V.—NO. XI. 31

482 R. H, Rastall—The Iron-fields of Lorraine.

deeper towards the west in French territory. On the east and south
the thickness is from 50 to 70 feet, but this increases to about
200 feet westwards and in Luxemburg, with a corresponding falling
off in quality. The ferruginous series consists of an alternation of beds
of oolitic iron-ores of various colours with limestones and occasional
marls. The iron-ores, which are locally known as Minette, have
been formed by metasomatic replacement of calcareous oolitic grains,
probably consisting originally of aragonite, while the cement has
chiefly remained calcareous. As before stated, the percentage of iron
varies regularly from north to south, and this has a most important
economic bearing. In Luxemburg the average*iron-content is 30
per cent or less, while in the south of the Briey plateau it rises to as
much as 40 per cent, with 9 to 14 per cent of lime and 4 to 7 per
cent of silica. In the Longwy and Crusnes fields the ores contain
less lime, while the silica rises to 20 per cent in some cases; the
proportion of phosphorus remains very constant throughout, averaging
about 1°8 per cent.

Hence the ores must be regarded as distinctly phosphatic, and it
was the introduction of the Thomas-Gilchrist process in 1882 that led
to the vast industrial development of this area.

Several careful computations of reserves have been made, and the
following figures are estimates of ore still available in the different.
districts and workable under present economic conditions :—

TONS.
Briey . i : 5 ‘ . 2,000,000,000
Longwy j 3 i - : : 275,000,000
Crusnes i i : 500,000,000
German Lorraine aindl Luxemburg . 2,000,000,000
Total 3 . 4,775,000,000

Of this total considerably more than half was in French territory,
including practically the whole of the higher-grade portion. The
potentialities of the western portion of the Briey plateau were not
known to the German authorities when peace was concluded in 1870,
and an endeavour to rectify the mistake then made must certainly be
regarded as one of the causes of the present War. The whole of
the Briey field as well as those of Longwy and Crusnes are
occupied by the Germans, and it is of interest to consider what
is now going on there. Lately published statistics relating to
Tiuxembure throw some indirect light on the matter. In 1912
the output of Luxemburg was 6,511,000 tons, and in 1916
6,752,000 tons. In 1917 the output fell suddenly to 4,502,000 tons,
and in August, 1918, some 450,000 tons still remained unsold in that
country, owing to excess of supply over demand. The consumption
of iron-ore in Germany at the present time is undoubtedly very
great, and the natural inference is that Germany is now exploiting
as largely as possible the richer ores of the Briey plateau and
neglecting the poorer ones of German Lorraine and Luxemburg.
It is also stated that there is an active demand for siliceous ores,
as opposed to the more calcareous varieties, and it is a natural
inference that ore of this kind is being obtained from the Longwy

G. W. Tyrrell—Petrography of South Georgia. 483

and Crusnes fields. Hence it is clear that German munitions of war
are being very largely manufactured from French ore, thus
diminishing the potential mineral wealth of that country, in addition
to the actual damage inflicted by the said munitions during the War.
These are facts which will have to be taken into consideration at
the Peace Conference.

I].—Apprrionat Nores on THE PerrrocRaPpHy oF SoutH Grorcia.

By G. W. TYRRELL, A.R.C.8c., F.G.S., F.R.S.E., Lecturer in Geology,
University of Glasgow.
ee rocks which form the subject of this paper were collected by
the captain of a whaling vessel belonging to the fleet of
Messrs. Salvesen & Co., of Leith, stationed at Leith Harbour, South
Georgia. ‘The collection reached me, for description, through the
kind offices of Mr. D. Ferguson, Mem. Inst. M.E., who recently
visited the island, and who has described its geological features.}
Two previous collections of rocks from South Georgia have been
described by me, one collected by Mr. Ferguson during his visit.,?
the other collected in the same way as the present set.$
The collection consists of twenty-six specimens, nineteen of which
are from Larsen Harbour, at the extreme south-eastern end of the
island, in the midst of the ‘‘altvuleanischer’’ area found by Heim.*
Three specimens are from Gold Harbour, on that part of the coast
that trends nearly due north and south near the south-eastern end ;
and four specimens are from King Haakon Harbour, about the middle
of the long, icebound, southern coast. Most of the material is
igneous, or derived from igneous rocks by alteration; the few
remaining specimens belong to the sedimentary series of which the
greater part of South Georgia is built. The rocks-may be classified
as follows :—
1. Ienrovs Rocks anp THEIR DERIVATIVES.
(1) Spilite.
(2) Soda-felsite (Quartz-felsite of previous paper).°
(3) Greenstone (Albite-dolerite ?).
(4) Epidosite and other Vein Rocks.

2. Sepimenrary Rocks.
1. Ienzous Rocks.

(1) Spilite.—Several specimens belong to this type, all derived
from Larsen Harbour. They are compact, grey-green, non-
porphyritic rocks, carrying veins of quartz, chlorite, and epidote.
In some specimens small amygdales of dark-green chlorite or
yellowish-green epidote occur.

1 “* Geological Observations in South Georgia’’: Trans. Roy. Soc. Edin.,
vol. 1, pt. iv, pp. 797-814, pls. lxxxi-xci, 1915.
2 “ Petrography of South Georgia’’: ibid., pp. 823-36, pl. xciv.

* “Further Notes on the Petrography of South Georgia’’: GEOL. MAG.,
dec. VI, Vol. III, 1916, pp. 435-41.

* ““Geol. Beob. ii. S. Georgien’’: Zeit. Ges. Erdk., 1912, pp. 451-6.

> Op. cit., p. 438.

484 G. W. Tyrrell—Petrography of South Georgia.

In section, the most typical rock (C10)! shows a thin network of
slender striated felspars, with nearly straight extinction, interspersed
with a few microphenocrysts which have a well-marked multiple
twinning, and the extinction and refractive index of almost pure
albite. he felspars of the groundmass are appreciably less sodic,
and belong to albite-oligoclase. The interstices of the felspar
network are filled with chalcedonic silica, chlorite (mostly in
amygdales), epidote, a little quartz, very minute felspar microlites,
and a dark-green indeterminate material. The chlorite amygdales
are often lined with a thin layer of cryptocrystalline silica, and are
further banded with concentric layers of slightly different varieties
of chlorite, or chlorite mingled with grains and rods of epidote.
There is not a trace of the original ferro-magnesian or iron-ore
minerals. They have all been replaced by chlorite and epidote,
with, no doubt, cryptocrystalline silica as a bye-product of the
reaction. Thin veins of quartz, chlorite, and epidote occur in the
rock. ‘his is a fairly typical spilite.

Another specimen (C11) shows the felspars still more thinly
dispersed in a dense groundmass, consisting mainly of a greyish-
green indeterminate material, with chlorite and a few felspar
microlites, still showing traces of its original texture. There are
numerous amygdales of uniform bright-green chlorite. The micro-
phenocrysts of albite tend to segregate into small groups; and
mingled with them are a few crystals of untwinned felspar, mottled
in polarized light, which appear to be soda-orthoclase. In one part
of the slide rounded areas of granular epidote become common.

A somewhat different type of spilite is- represented by other
specimens. In the mass they are dark-grey, compact rocks, with
numerous spherical cavities filled with radiating needles, of green
epidote. In thin section they show numerous small laths of albite-
oligoclase, with a few stouter microphenocrysts, in a dense
groundmass consisting of minute felspar microlites, abundant grains
of ragged skeletal iron-ores, and a pale yellowish-green fibrous
chlorite which no doubt represents original pyroxene. Large
euhedral crystals of magnetite are scattered sparingly over the
section. Large rounded patches or amygdales of epidote and chlorite
also occur, the epidote forming masses of radiating crystals, with
rosettes of chlorite filling the remaining interspaces. Sometimes,
however, chlorite fills the amygdale to the almost complete exclusion
of epidote, and shows a remarkable violet polarization tint. Epidote
and chlorite occur only sparingly in the groundmass of these rocks.
They are to be regarded as falling midway between the typical
spilites and the more mafic varieties described below.

Two of the rocks (C 18, C19) are richer in mafic constituents than
those described above. The hand-specimens are compact, dark-grey
rocks, becoming grey-green upon weathering, and showing numerous
veins and impregnations of white quartz, pyrites, and magnetite.
The thin sections exhibit a dense, closely-woven mesh of minute,
diverse, unorientated felspar laths (albite-oligoclase), with abundant
small skeletal grains of iron-ore, chlorite, and an indeterminate grey

1 The numbers within brackets refer to those of the specimens preserved in
the Hunterian Museum, University of Glasgow.

G. W. Tyrrell—Petrography of South Georgia. 485

material probably representing original pyroxene. There are also
rare microphenocrysts of oligoclase, and occasional small patches of
quartz, epidote, and chlorite. The quartz is undoubtedly secondary,
and introduced at the same time as the quartz veins by which the
rocks are penetrated. ‘These rocks may be regarded as basic types of
spilite intermediate between that rock and mugearite.

(2) Soda-felsite.—Two non-spherulitic felsites (C14, C15), which
differ in no essentials from those described in a previous paper as
quartz-felsite,’ occur in the collection. The phenocrysts of quartz,
albite, and orthoclase are perhaps less abundant, the groundmass
finer-grained and more abundantly epidotized than in the formerly
described specimens. These rocks greatly resemble the soda-felsite
or soda-granite-porphyry of Porthallow Cove, Cornwall, which is
also associated with a spilitic series.”

With the soda-felsites may be described a quartz-trachyte (C 20)
from the same locality (Larsen Harbour). In thin section this rock
shows numerous irregular areas of turbid, mottled, untwinned
alkali-felspar, together with a few, elongated, simply twinned laths
of sanidine, and irregular areas of quartz, in a groundmass consisting
of minute, fluidally arranged laths of albite-oligoclase, a little
orthoclase, and abundant interstitial quartz. The sanidine laths and
large quartz areas are frequently invested by an irregular,
discontinuous zone of cloudy alkali-felspar, which envelops the
fluidal laths of the groundmass. While many of the constituent
minerals are quite fresh and undecomposed, the rock is impregnated
with irregular areas of epidote and particles of pyrites. This rock is
clearly related to the soda-felsites, but differs in being less quartzose
and in possessing a trachytic groundmass.

(3) Greenstone (Albite-dolerite?).—In. hand-specimens these are
fine-grained ‘‘ greenstones”’ (C5, C6, C7), all from Larsen Harbour,
penetrated by quartzose veins, and impregnated with pyrites and
quartz. One rock (C6) shows numerous amygdales filled with
greenish-black chlorite. In thin section the principal minerals,
shown are albite-oligoclase in thin laths, enclosed ophitically in
masses of chlorite which doubtless represent original pyroxene.
The felspar laths are often cloudy and mottled on account of minute
inclusions of quartz, epidote, and chlorite. Ilmenite in process of
alteration to leucoxene is an abundant constituent, and there is a
considerable quantity of interstitial secondary quartz and epidote.
A prominent feature in one of the rocks (C6) is the occurrence of
numerous, large, rounded vesicles filled with rosettes of yellow-green
chlorite which shows in great perfection the characteristic ultra-
blue polarization tints. C 5 is of finer grain than C 6, and is devoid of
amygdales. C7 has abundant secondary quartz and pyrites. These
rocks are much decomposed greenstones, but enough is left of their
original minerals and texture to establish the fact that they belong
to the spilitic series, and were probably oligoclase or albite-
dolerites similar to the types that accompany spilites in other regions.

(4) Epidosite and other Vein Rocks.—In the previous paper

1 Geox. MaG., Dec. VI, Vol. III, pp. 438-9, 1916.

2 Geology of the Lizard and Meneage (Mem. Geol. Surv.), 1912, p. 186;
see pl. xii, fig. 6.

486 G. W. Tyrrell—Petrography of South Georgia.

progressive epidotization of certain obscure igneous rocks was shown
to occur, resulting, in its final stage, in the production of a rock
composed mainly of epidote and quartz.! The same characteristic
reactions are exemplified in the series of rocks now under description,
with the addition that veins of epidotic material are now seen to be
common. ‘These are especially abundant in the spilites. Their
average thickness is about 1 inch, but they may swell out to a width
of 8 inches. They consist of a hard, dense, pale-yellow epidosite,
containing irregular patches and segregations of greenish-black
chlorite, and associated with a compact flint-hard, grey-green
material. In thin section the epidosite appears extremely turbid,
and is only translucent on the thinnest edges of sections, where it is
seen to consist of an almost cryptocrystalline aggregate of epidote
and silica. The grey-green flinty material is even denser. It is
very feebly birefringent, and is irresolvable even under a +in.
objective. It carries tiny patches of epidote and quartz. The
epidosite encloses irregularly-shaped areas which have a narrow
border of granular epidote, or of epidote and quartz, with the
remainder of the space filled with radiate masses of chlorite in which
particles of leucoxene are enclosed. Smaller areas are filled with
epidote and quartz, or with epidote alone, suggesting that the order
of deposition has been first epidote, then quartz, and finally chlorite.
The boundaries of the veins against the enclosing spilite are generally
marked by a shght segregation of iron-ores within the rock.

Three specimens of massive epidosite occur in the collection
(C9, C13, C24), all from Larsen Harbour. They are hard, dense,
splintery rocks of yellowish-green colour, which, in thin section,
show an intimate granular admixture of epidote and quartz. As
noted in the previous paper, the epidote grows euhedrally into the
quartz wherever the latter mineral forms plates large enough for
the relation to be observed. Chlorite, and pyrites in euhedral
erystals, occur in varying amounts.

Quartz veins also occur abundantly in these rocks. In one
specimen (C 18d) the rock (spilite) has been veined in all directions,
leaving sharply angular fragments of country rock entirely surrounded
by quartz. These fragments are highly silicified, as is also the rock
adjacent to the sides of the veins. The quartz is very finely
granular, except in some later veinules. Intermingled with the
quartz are euhedral crystals of epidote and pyrites, with flakes of
chlorite, and irregular masses of magnetite (strongly attracted by the
bar magnet). In another specimen (C25) the quartz is much
coarser in grain, and in addition to the above-mentioned minerals
also carries irregular patches of a translucent, reddish, optically
isotropic ore-mineral, which is probably chromite. In C18a@ there
are curious, spherical, amygdale-like areas of very fine-grained quartz,
which enclose sectors in which the quartz shows a concentric and
radiate structure, as shown by the appearance of a black cross
between crossed nicols. Other similar areas carry large euhedral
crystals of pyrites. Still another shows a narrow border of minutely

1 Grou. MAG., Dec. VI, Vol. III, pp. 439-40, 1916.

G. W. Tyrrell—Petrography of South Georgia. 487

granular quartz, followed by a discontinuous zone of chlorite, with the
interior of the cavity filled by coarsely granular quartz.

With these rocks may be described a fine, carnelian-red, jasper-
rock (C26—Larsen Harbour), which shows, in thin section, a
groundmass of cryptocrystalline silica thickly impregnated by
hematite in peculiar globular, clubbed, or roughly radiate forms,
viving a texture which, after an obvious resemblance, may be called
ameboid. The rock also carries large irregular masses of pyrites.
This rock may represent the siliceous material often found associated
with spilites, especially in the interstices between pillow-form masses.

2. Sepimentary Rocks.

The collection includes typical mudstones from King Haakon
Harbour (C3, C4), with only the beginnings of cleavage. These
rocks are penetrated by a great number of very thin, fine veins of
quartz. From Gold Harbour there comes a fine-grained, banded
greywacke (C22), consisting of numerous thin alternations of
arenaceous and argillaceous material. The interest of this rock is
that it shows in a superlative degree the relative resistance of the
two types of material to differential movement. The arenaceous
bands show frilled and puckered folding; but in the adjacent
argillaceous bands each pucker is represented by a line of strain-slip.
As the argillaceous bands predominate, the rock, as a whole, splits
easily along the strain-slip cleavage. Some of the arenaceous bands
contain a few large crystals of quartz and albite, which are deformed,
and in the case of the felspar sericitized, but which have nevertheless
formed nuclei of resistance, causing the folds to pass round them.
A similar rock has been described and figured in an earlier paper.’

Other rocks from King Haakon Harbour (C1, C2) are sheared
erystal-tuffs with sporadic scapolitization, entirely similar to those
described in a former paper.* They contain crystals of orthoclase
and albite, and fragments of shale, as augen in a sheared, almost
eryptocrystalline, groundmass, consisting apparently of sericitized
felspar and chalcedonic silica. The scapolite occurs in compact,
granular masses which appear to be pseudomorphs after rock-
fragments, but the character of the latter is completely obliterated.
The foliation is outlined by a wispy, greyish, argillaceous material
the character of which cannot be determined. A considerable
amount of pyrites has been introduced along the foliation planes.

A specimen from Gold Harbour (C 23) appears to have been a tuff,
but has undergone much more advanced shearing than the rocks
from King Haakon Harbour. Only a few remnants of quartz and
felspar are left as augen, in a thoroughly foliated, granulitized paste
of quartz and felspar, with filmy sericitic mica. Similar rocks from
Gold Harbour were described in a former paper.?

3. ConcLuUsIons.
The most striking new fact afforded by the study of this
collection of South Georgia rocks is the recognition of a spilitic
1 ** Petrography of South Georgia’’: Trans. Roy. Soc. Edin., vol. 1, pt. iv,

p. 826, pl. xciv, fig. 1, 1915. * Tbid., pp. 827-30.
3 GEOL. MaG., dec. VI, Vol. III, p. 436, 1916.

488 G. W. Tyrrell—Petrography of South Georgia.

series of igneous rocks in and about Larsen Harbour at the south-
eastern end of the island. The tectonic inferences to be drawn
therefrom are so important that it was thought advisable to send the
slides to Dr. J. S. Flett, F.R.S., for his opinion as to their spilitic
nature. He has very kindly confirmed this identification. The
diabases and melaphyres, described (macroscopically) by Heim, no
doubt belong to this series. Furthermore, the epidotized lavaform
and tuffaceous rocks of doubtful affinities, described by me in the
last paper, almost certainly belong to the series.!

Associated with the dark-grey or grey-green spilites are light-
coloured rocks which were previously identified as quartz-felsites.
Dr. Flett prefers to call them soda-felsites; and this is undoubtedly
the better term since the rocks are very rich in albite, and must be-
regarded as consanguineous with the albite-rich spilites. The
alaskite from Cooper Island, described in the last paper, is perhaps
also to be correlated with this series.

Furthermore, the badly decomposed rocks here described as green-
stones were probably once dolerites with a sodic plagioclase, oligoclase
or albite, petrographic types which elsewhere are closely associated
with spilites and soda-felsites. The ophitic dolerite from Cumber-
land Bay and the epidiorite (meta-dolerite) of Gold Harbour,
described in previous papers, are probably also to be associated with
the spilitic series. These rocks, however, differ entirely from the
ophitic dolerites and basalts from Larsen and Slosarezyk Harbours in
the last collection.2, The latter rocks are very fresh, with a much
more calcic plagioclase than is general in the spilitic series, and
furthermore have escaped the epidotization which is so characteristic
of that suite. Hence it is believed that they belong to an intrusive
series of much younger date than the spilitic series.

From consideration of the evidence now accumulated South
Georgia consists principally of a folded sedimentary complex,
including greywackes, slates, mudstones, and tuffs, of uncertain
age, probably Paleeozoic in the main, but perhaps ascending into the
Mesozoic. It contains a spilitic series of igneous rocks at the
south-eastern end of the island, and intrusive rocks of the same group
occur within the sediments at least as far away as Cumberland Bay.
Rising behind the dark, ‘‘altvulcanischer”’ region around Larsen ‘and
Drygalski Harbours, Heim saw a great, light-coloured massif, the
composition of which was believed to be granito-dioritic from the
evidence of the moraine material within the area.2 The specimen of
granite-porphyry collected by Mr. Ferguson from the glacial material
at Moraine Fiord probably belongs to this or a similar complex.*

Spilites are characteristically associated with rocks of Paleozoic or
Pre-Paleozoie age; and if, this relation holds in South Georgia,
the presence of spilites may be held to reinforce the view that the
sedimentary series of the island is mainly of Paleozoic age. The

Ibid., pp. 439-40.

Ibid., p. 437.

Op. cit., p. 454.

Trans. Roy. Soc. Edin., vol. 1, pt. iv, p. 830, 1915.

me O BH

Herbert L. Hawkins—Studies on the Echinoidea. 489

lithologically very similar sedimentary series of the South Orkneys
is definitely known to be of Lower Paleozoic age (Silurian) from the
evidence of graptolites.! It is a fact suggestive of close geological
relationship between South Georgia and the South Orkneys that
a small pebble of typical spilite was found by me in a series of rocks
collected by the Scotia Expedition from Coronation Island in the
South Orkneys.?

According to Dewey and Flett spilites are the characteristic
- voleanic rocks of districts that have been undergoing long-continued
. subsidence.? This relation receives further exemplification from
South Georgia, where the sedimentary series is of great thickness
and continuity, and lithologically is of shallow-water origin.
Benson has shown that spilites are not necessarily indicative of
deep-water conditions as supposed by Steinmann and _ others.*
Lastly, attention may be drawn to the fact that the South Georgia
sediments are radiolarian, another character often exhibited by the
sedimentary rocks associated with a spilitic suite.

The existence of a spilitic suite in South Georgia and the South
Orkneys has an important bearing upon the tectonic relations of
these islands. The balance of evidence may now be said to tip
definitely against Suess’s interpretation of their structure. He
believed that they formed part of a great eastwardly-directed loop,
homologous with the Antilles, connecting the Patagonian Andes
with the mountain ranges of Graham Land. The continued absence
of typical Andean volcanic rocks in spite of repeated collection of the
rocks of South Georgia, as well as the existence of a spilitic series,
favours the interpretation that South Georgia and the South
Orkneys are remnants of an ancient continental land which once
occupied the South Atlantic.°

TiI.—MorpuHorogicaL Srupres on THE EcHINoIDEA HoLeEcryPoIpa
AND THEIR ALLIES.

By Hersert L. HAWKINS, M.Sc., F.G.S., Lecturer in Geology, University
College, Reading.
VIII. On Pyeasrrives, Lovin, A ProptemMaticaL Hovevryporp.
(PLATE XVII.)
1. Lyrropuction.
[ may be thought that some apology is due to the readers of this
Magazine on the ground of the largely zoological bearing of this
paper. But in the opinion of the writer no such apology is necessary.
Zoology is paleontology brought up to date, and ontogeny is but
a compressed and individualistic type of phylogeny; so that in
spirit, though not in matter, this paper is no less appropriate for
1 J. H. Pirie, Proc. Roy. Soc. Edin., vol. xxv, pp. 463-70, 1905.
2 Op. cit. supra, p. 833.
3 Op. cit., p. 242.
4 W. N. Benson, ‘‘ Spilite Lavas and Radiolarian Rocks of New South
Wales’’: GEOL. MAG., dec. V, Vol. X, pp. 17-21, 1913.

> J. W. Gregory, ‘‘ The Geological Relations and some Fossils of South
Georgia’’: Trans. Roy. Soc. Edin., vol. 1, pt. iv, pp. 817-22, 1915.

490 Herbert L. Hawlhins—Studies on the Echinoidea.

publication here than its seven predecessors have been. According
to Lovén himself, the minute Echinoid which supplies the text for
the sequel is to be considered a survivor, not merely of the
Holectypoida, but of the most primitive family of that Order—
a kind of Lingula or Nucula among Irregular Kchinoids. Although
one of the main purposes of the following pages is to offer reasons for
disbelieving that contention, nevertheless Pygastrides, as far as the
only specimen known is concerned, is for all practical purposes
primitively Holectypoid in essential characters. This seeming
paradox may be resolved by the anticipatory remark that Lovén’s _
so-called genus is believed to be an early post-larval stage in the
development of some more completely Irregular adult form. It is
ontogenetically related to that problematical adult, just as the
Pygasteride must be phylogenetically ancestral to it.

At the time of its description by Lovén Pygastrides was almost
the only developmental stage of its kind known. Now there are
several comparable ontogenetic phases available for comparison,
notably the gnathostomatous young of Hehinonéus cyclostomus and the
originally endocyclic early post-larval forms of Abatus cavernosus and
Echinocardium flavescens. The three different ontogenetic lines thus
indicated serve to prove conclusively the phylogenetic relationship
of the Holectypoida to the Irregular Echinoids. Even if Hehinonéus
be considered to be an Holectypoid (and I incline to believe that
it should be so classed), its affinities with other groups are many
and manifest. Pygastrides, as the following arguments seek to show,
must be a young stage of some other type of Irregular Kchinoid,
while Adatus is a Spatangid of the Spatangoids.

In the course of the discussion on the affinities of Pygastrides,
certain morphogenetic points arise. These are mainly concerned
with the perignathic girdle, so that this paper is in some respects
a direct sequel to its three immediate predecessors. It was thought
better to keep it distinct from them because, while they were based
upon direct observation, the substratum on which the following
arguments rest is theoretical, although it seems to me to be more
secure than mere conjecture. :

2. Résumé oF THE CHARAcTERS oF PYGASTRIDES RELICTUS.

In 1874 Lovén (Htudes sur les Hehinovdées, p. 79), in a footnote
to a description of certain ‘‘ Echinoconide ”’ (Holectypoida), mentioned
the existence of a small recent form from the Caribbean Sea that
he believed to be a living species of Pygaster. He gave it the
nomen nudum of Pygaster relictus. After a delay of fourteen years,
during which ‘the little thing ’’ succeeded in avoiding capture, in
spite of ‘‘most energetic exploration”’ of its habitat, Lovén gave
a full and beautifully illustrated description of the solitary and
imperfect specimen on which his previous comment had been bae d
(1888, ‘‘Ona Recent Form of the Echinoconide’’). Detailed study of
the small corona showed that it differed in many important respects
from that of Pygaster, and caused Lovén to diagnose a new genus,
Pygastrides, for its reception. Pygastrides relictus still remains
unique, a sufficiently remarkable fact in view of the amount of

Herbert L. H Tolinelsradies on the Hchinoidea. 491

deep-sea exploration that has been achieved since 1888. Further
discussion of its characters and affinities must needs be based on new
knowledge of its alleged relatives.

The following is an abridged account of its salient features taken
from Lovén’s description :—

Length. ; : : . 38-dmm.

Breadth . “ : i . 3:41mm.

Height . ; : : . 2-16mm. (0-62 of length).
Peristome diameter . i . [1-015 mm.] (0-29 of length).

Corona.—Obscurely subpentagonal; tumid. _

Apical system.—Wanting, apparently central in position.

Peristome.—Central, very slightly invaginated. Outline irregularly
circular. The epistroma not extending quite to the margin, leaving
a delicate inner rim in which occur narrow branchial (?) incisions.
Interradial margins built of large, single primordial interambulacrals.
Ambulacral margins built of high, narrow primordial ambulacrals.
Externally each ambulacral bearing a large ‘‘epistromal prominence ”’
with a glossy and minutely punctate surface, the pairs of these
meeting adorally to a large, single, perradially situate spheeridial pit.

Perignathie girdle.—Paired ambulacral processes of slightly
cuneiform shape, expanding distally, meeting the floor of the test at
a very acute angle. The processes are apparently placed over the
adradial sutures. The figure (Lovén, pl. i, fig. 5; here Pl. XVII,
Fig. 2) is hard to understand. It gives the appearance of a specially
intercalated plate as the foundation of each process, a most anomalous
condition. Possibly the apparent sutures represent the raised edges
of the articulation between the processes and the corona. ‘here
seem to be no interradial perignathic elements.

Periproct.—Mostly broken away, but apparently projecting into
interambulacrum 5 almost to the ambitus. Posterior margin broad
and symmetrical.

Ambulacra.—Composed of simple, rectilineal plates throughout.
No biporous plates. (In Lovén, pl. i, fig. 5, the proximal ambulacral
in column IIId seems to show two pores; but this is in contradiction
to the statements in the text, and is probably due to an error in
drawing or printing.) Pore-pairs confluent, dissimilar; external pore
round, internal pore slit-like; placed near the adapical transverse
margins of the plates. Peripodia sunken.

Interambulacra.—Built of normal, mostly unituberculate plates.
Proximal unpaired plate very large, variable in size and shape in the
several areas. In Lovén’s figure (here Pl. XVII, Fig. 2) plate la, 2,
is shown to be low and cuneiform, tapering towards the interradial
suture. Similarly placed plates in other areas tend towards this
character.

Ornament.—Primary tubercles large, scrobiculate, crenulate, and
with perforate mamelons. Approximately similar in size on inter-
ambulacra and ambulacra, and in both arranged in regular series.
Surface of both areas thickly studded with glossy, ovoid protuberances,
often grouped into scrobicular circles around the main tubercles.

Habitat.—Near Virgin Islands, between 200 and 300 fathoms.

492 Herbert L. Hawkins—Studies on the Echinoidea,

3. Is Py@asTripEs an Hotecryporp ?

Ignoring the question discussed in section 4, it is a matter of
considerable interest and importance to ascertain the systematic
position which Pygastrides can occupy. There can be little doubt.
that Lovén was right in regarding the ‘‘ genus” as one of the
‘‘Hchinoconide’’, i.e. Holectypoida. Huis association of it with
Pygaster, while still eminently reasonable, is not quite so inevitable.
It would be difficult to locate it in any of the families of the
Holectypoida as at present recognized—ait combines certain characters
that occur in all families of the order, and possesses some that are
not found in any of them.

The Holectypoid qualities may be thus summarized :—The
approximately radial symmetry of its outline; the central, circular,
fairly large peristome with apparent ‘‘branchial incisions” and
a perignathic girdle (hence presumably a lantern); the. adapically
situated periproct, apparently in contact with the apical system and
not located in a suleus; the non-petaloid podial pores; the serial
arrangement of primary tubercles on both areas and their scrobiculate,
crenulate, and perforate nature. Such an assemblage of characters,
nearly all of a positive type, makes it impossible to regard Pygastrides
as belonging to any order of Irregular Echinoids but the Holectypoida.

Nevertheless, there are certain features in Pygastrides which do
not agree with the Holectypoid diagnosis. The perignathic girdle
seems devoid of interradial elements; the ambulacra show no trace
of ‘‘plate-crushing”’, particularly near the peristome, and their pores
are conjugate and dissimilar, perforating the plates near the adapical
margins; the spheridia are single, deeply sunken, and perradial in
position; the tubercles seem to be all primaries, and the granulation
is pecuhar. It might reasonably be argued that these (chiefly
negative) differences are due to the small size of the specimen. But
in examples of Discordes divont and Conulus subrotundus of scarcely
greater dimensions the full Holectypoid requirements are fulfilled.

Pygastrides may, then, be considered as representing an Holectypoid
in which certain features are lacking, and in which one set of
structures, the spheeridia, is apparently abnormally situated. The
disposition of the sphzeridia in the fossil Holectypoida is not yet
known with certainty; they were presumably not deeply sunken;
but in Hehinonéus they occur on the ambulacral plates, superficially
placed, and to the number of three or four in each area.

In an attempt to trace the affinity of Pygastrides with any of the
families of the Holectypoida less definite evidence appears. To the
Pygasteridee (and especially to Plestechinus) it is similar in symmetry,,
peristome (save for the smallness of the branchial incisions),
perignathic processes (apart from their angle of setting and the lack
of buttresses), periproct, and tuberculation. The simplicity of its
ambulacral plating, though too complete, is another link with this
primitive family. Pygastrides resembles the Discoidiine in the
relatively large size of the primordial coronal plates and in the
feeble development of the branchial incisions. The peculiar structure
of the interambulacra near the peristome is extraordinarily like that
contiguous to the “false ridges” of Discoides. It suggests that the

Herbert L. Hawkins—Studies on the EHchinoidea. 493

primordial interambulacral plates block the path of the advancing
columns, giving a type of ‘‘plate-crushing”’ comparable with that

described by me in Lovenia forbes’. The minor ornament of the test —
is suggestive of some of the guttate granules of Holectypus depressus,
and perhaps of the glossy granulation of the adoral surface of Conulus.

Thus, while showing a preponderance of Pygasterid characters,
Pygastrides exhibits important differences from the known members
of that family, combining in the one small corona qualities that are
shared among all the families of the Holectypoida, and especially
suggesting some affinity with the Discoidiine. It may be defined as
a generalized Holectypoid with mainly primitive traits.

Finally, there is one feature in which Pygastrides probably differs
from the normal Holectypoida and is certainly different from their
nearest living representatives. Itisa deep-water form. Although
it is difficult to speak with certainty on the bathymetric range of
fossil types, all the evidence seems to show that the Pygasteride
(to which Pygastrides makes the closest approximation) were
essentially denizens of shallow water. The latest Pygasterids, such
as Anorthopygus, are only known from the littoral facies of the Chalk-
sea deposits (e.g. the Hibernian Greensand and the Haldon Hill
remanié), never being found in the regions of open-water ooze.
Echinonéus abounds chiefly between tide-marks, and Micropetalon is
not known from a greater depth than 24 fathoms. Possibly some of
the Cretaceous Holectypoida, such as Conulus albogalerus, may have
inhabited water of considerable depth, but there is no proof that they
lived at such a depth as 250 fathoms. Moreover, they are morpho-
logically- the least like Pygastrides of any members of the order.
This point, though of little systematic value by itself, is worth
noting in conjunction with the other divergences of Pygastrides trom
the Holectypoid type.

4. Is Pre@asrripes Apuutt, or A Post-Larvat Sracr?

It follows from the discussion in the preceding section that
Pygastrides, if it be a genuine genus, must find a place among the
Holectypoida, although the diagnosis of the Order would need some
modification for its inclusion. As at present known, it cannot
possibly be associated with any other order of Kchinoids.

Lovén seems to have been convinced that this small specimen is
adult. He supported his contention by reference to the ‘‘rather
thick” and rigid test, the character of the tubercles and epistromal
prominences, and the depressed ambulacrals. He further remarked
that, were it larger when adult, specimens would hardly have
escaped capture. This last contention may be dismissed at once,
since it is based upon the assumption that the adult form would
closely resemble the small specimen. It does not follow that,
supposing P. relictus to be an ontogenetic phase, the adult is not
already known, the correlation of the two being at present
impossible. Zoologists are painfully aware of the difficulty of
identifying a larval stage with its adult form, even when both are
fairly abundant. It is reasonable to suppose that, if P. relictus is a
young stage, its adult equivalent has already been discovered.

494 Herbert L. Hawkins—Studies on the Echinoidea.

As Lovén admitted, it is difficult to derive satisfactory evidence of
the age of Pygastrides owing to the absence of the apical system, but
to my mind the indirect evidence that indicates its immaturity is
conclusive.

In point of size P. relictus is far smaller than any known adult
Echinoid, fossil or recent. Lovén (Etudes, p. 79), regarding it as
a Cretaceous survival, remarks, ‘‘La plupart des formes crétacées
retrouvées vivantes a de grandes profondeurs sont comparativement —
petites.’ But. Pygastrides is not ‘‘comparativement”, it is
‘‘absolument petit”. In the paper devoted to this problematical
Kchinoid Lovén admits that ‘‘ Littleness . . . seems to be another
character by which it departs . . . from the recent forms among
which it lives”. The minute size, », though not conclusive, is strong
presumptive evidence for youth.

In the absence of definite measurements of the thickness of the
test, it is difficult to frame an opinion on the value of Lovén’s
description ‘‘rather thick”. There is no evidence that young
Kchinoids of as much as 3°5 mm. diameter are so little calcified as to
undergo shrivelling when dried— a quality that Lovén apparently
would have expected in Pygastrides were it truly neanic. chinonéus
cyclostomus seems to have a perfectly rigid corona when it has
attained comparable dimensions, and certainly Parechinus miliaris is
quite massive at that size.

Since P. relictus is an Irregular Echinoid, the tubercles, which
Lovén cites as showing no specially youthful characters, are
certainly disproportionately large, and remarkably sparse. They
compare well with those of Abatus cavernosus (see Pl. XVII, Fig. 5),
25mm. in diameter, as figured by Mortensen (Schwed. Sudpolar.
Exped.). They are considerably larger in proportion to the size of
the test than in any adult Holectypoid, and even than in examples
of Plesiechinus ornatus of less than 8mm. in diameter. Since the
tubercles of the Holectypoida are larger than those of other Irregular
orders (excepting the specialized ones in some Heart Urchins), and
they are constantly of fair dimensions in the relatively more
primitive Regular Kchinoids, their large proportions in Pygastrides
certainly suggest that youthfulness is the cause.

So little is known of the early post-larval stages of many groups
of Echinoids that the character of the ‘‘epistromal protuberances”’
can hardly be used as a criterion of age. There are plenty of
granules and glassy tubercles on Hehinonéus when the diameter is
only 4mm.

Reference to the ambulacral plates of P. relictus seems to me to
afford more indication of youth than of maturity. It is true that,
with the exception of the primordial plates of the columns, the
ambulacrals:are all ‘‘ Cidaroid’”’ in character; but they are not lower
than those of Echinonéus at 38:7mm. diameter. Moreover, if
Pygastrides is an Holectypoid, and an adult one, it is unique in the
order in having no suspicion of ‘‘plate-crushing’’. In the small
gnathostomatous Lechinonéus of about the same size there are already
demi-plates in the ambulacra, and in specimens of Plesiechinus
ornatus not exceeding 5mm. in diameter some of the plates are

Herbert L. Hawkins—Studies on the Echinoidea. 495

already distorted. Thus the extreme simplicity of the ambulacral
plating is again suggestive of youth.

Other features in P. relictus which are concordant with the view
that it is a young form are: (1) the great size of the proximal
coronal plates, (2) the general rotundity of the test, and (3) the
relatively large size of the spheeridia.

The position of the periproct gives little help in this discussion.
Certainly, if Pygastrides were adult, it would prove to be the least
progressive of all known living Irregular Kchinoids in this respect
(excluding perhaps ‘‘ Vucleolites’’ recens), being no more advanced than
the Lower Jurassic Plestechinus. But even so advanced a Spatangoid
as Abatus cavernosus (Pl. XVII, Fig. 5) has the periproct on the
adapical surface and in contact with the apical system when it has
attained a diameter of 2°5mm., while at 1:9mm. it is definitely
endocyclic. A less specialized Irregular Echinoid might well have
a ‘‘ Plesiechinoid”’ periproct when it had reached the dimensions of
Pygastrides.

As a result of the considerations put forward above, I am
conyinced that Pygastrides relictus is an early post-larval form of
some larger species, the adult stage being, in all probability, some
type of Irregular Kchinoid already known.

5. CompaRIsoN oF PYGASTRIDES WITH E/CHINONEUS OF THE SAME SIZE.

For the purpose of this comparison I have relied upon Westergren’s
beautiful drawings (1911, Mem. Mus. Comp. Zool. Harvard,
vol. xxxix, No. 2, pl. x1).

The corona of Pygastrides is more circular in outline and more
elevated than that of Hchinonéus at 3:7 mm. diameter.

The peristomes of the two forms are similar in proportion and
shape, but in Hehinonéus the primordial coronal plates are considerably
reduced in size. There are three spheridia in each ambulacrum in
Echinonéus, in contrast to the single one in Pygastrides.

The perignathic girdle is in a far higher degree of development in
Pygastrides than in Eehinonéus, and the processes are only partly
based upon the ambulacral plates.

The periproct of Hehinonéus has already reached its adoral situation
at this stage of development—a marked advance on its condition in
Pygastrides.

The ambulacra of Hchinonéus have the primordial plates not
strikingly dissimilar from the rest, while in Pygastrides these plates
are very high. Demi-plates occur already in the former type, while
there seems to be no trace of disturbance in the regularity of the
shape of the ambulacrals in the latter. The pores of Hchinonéus are
round, disjunct, and normally situated in oblique pairs on the more
adoral parts of the plates—the reverse is the case in Pygastrides.

In the interambulacra a similar relation of the primordial unpaired
plates exists to that found in the ambulacra.

The tuberculation of Hehinonéus at 4°4mm. is closely comparable
with that of Pygastrides.

The young forms of Hehinonéus occur between tide-marks with the
adults, while Pygastrides was dredged from deep water.

496 Herbert L. Hawkins—Studies on the Echinoidea.

An analysis of the above comparison shows one feature of great
significance. In practically every quality in which the two forms
differ Pygastrides proves to be the less advanced from the Regular
(or better, Pygasterid) condition. It is, like Pleszechinus, a Regular
Kchinoid save for the (incomplete) posterior migration of the
periproct. Thus, if it really is a young stage, it must be affiliated to
some species that is less remote from a primitively Holectypoid
condition than ZEehinonéus. At least, Pygastrides cannot be a stage
in the development of that genus.

6. Tur PropasteE ApuLT oF PYGASTRIDES.

One of the most obvious qualities in the structure of Pygastrides is
the position of the spheridia. ‘hese are single, and placed in
considerable depressions on the perradial lines. ‘This is in complete
contrast to their disposition in Hehinonéus (and probably in the
fossil Holectypoida), and in the Cassidulide and Spatangide. It
compares with their arrangement in Regular Echinoids, but such
comparison is vitiated by the undoubtedly Irregular affinities of
Pygastrides. The only groups of Irregular Echinoids which possess
single, perradially situate spheridia are the three Clypeastroid
families of the Fibulariide, Laganide, and Seutellide. In them,
the spheeridia are deeply sunken, and in some cases entirely buried,
in the test-surface; the spheeridial pits of Pygastrides are unusually
deep. Unless it can be shown that spheridia are capable of migration
during ontogeny (a most improbable occurrence), it must be assumed
that the adult stage of Pygastrides has deeply sunken, perradial
spheeridia. These need not of necessity be single, since new
spheridia might be developed with advancing age; but among the
known adult Irregular Echinoids that have median spheridia, they
seem to be always solitary. ‘his evidence, then, limits the choice
of an adult for Pygastrides to three families of the Clypeastroida, and
I cannot imagine that it is deceptive.

Turning now to the proportions of the proximal coronal plates:
their great size in comparison with the others is at once apparent.
They form a strong, broad border to the peristome, strikingly unlike
the condition prevalent among most Echinoids. The superficial
resemblance of this primordial cycle to the perignathic structures of
Discoides has already been noted—it is doubtful whether a true
morphological correspondence exists. The elongated ambulacrals
are reminiscent of those adoral to the phyllodes in the Cassiduloida,
while the irregularity of the interambulacrals enhances the
resemblance. Indeed, apart from the presence of a perignathic
girdle and the position of the spheeridia, the peristorial parts of the
corona of Pygastrides might easily change into a iruly Cassiduloid
pattern. The processes might be vestigial structures, destined for
resorption as in Eehinonéus, but the singleness of the spheridia
seems a fatal bar to the maintenance of the comparison.

Again, the proximal coronals of Pygastrides are closely similar to
those of Hehinocyamus (Pl. XVII, Fig. 4), a small genus that retains
throughout life many primitive Clypeastroid features. For example,

H. erbert L, Hawkins—Studies on the EHchinoidea. 497

the corresponding plates of an Hehinarachnius of 6:5 mm. diameter
(about twice that of Pygastrides), figured by Lovén (Htudes,
pl. i, fig. 245), are practically identical in proportions with those of
Echinocyamus. In the Clypeastroids, however, the succeeding
ambulacral plates are high and hexagonal, unlike the ‘‘ Cidaroid ”’
ambulacrals of Pygastrides. Since all coronal plates undergo
considerable changes in size, and often in shape, during the growth
of the test, this difficulty, though real, is not insurmountable. The
“‘ Bothriocidaroid’’ character of the extra-petaloid ambulacrals of
the Clypeastroids is a sign of their obsolescence—they would hardly
be in that condition when first developed.

The globular form of Pygastrides makes it difficult to suppose that
it would develop into a discoid Scutellid, although such a change
would be by no meansimpossible. However, most of the Fibularide,
especially /ibularza itself, have elevated tests that do not differ
seriously in their proportions from those of Pygastrides.

The peculiar multiporous plates of the ambulacra of the
Fibulariide are certainly very different from those of Pygastrides,
but there are indications of disturbance in the latter. The
anomalous nature of the pore-pairs, with a round znternal pore, and
their position near the adapical margins of the plates, seem to
indicate some aberrant development. The rows of pores on the
Fibularid ambulacrals are similarly placed.

A review of the above arguments gives the following conclusions.
The position of the spheeridia, if it be a reliable character, points
definitely to the Fibulariid, Laganid, or Scutellid nature of the adult
of Pygastrides. The relations of the proximal coronal plates do not
earry the argument much further, but they are generally Clypeastroid
in character, with some resemblances to the Cassiduloid quality.
The general shape of the corona is more suggestive of a Fibulariid
than of any other likely adult. So that the balance of evidence
tends to indicate’ that Pygastrides is an early post-larval stage of
some such genus as Pibularia. The characters of the perignathic
girdle are not antagonistic to such a conclusion (see section 7), but
the nature of the ambulacra introducesa difficulty. In Hchinocyamus
and its allies, the extra-petaloid ambulacrals are high, and each
plate is perforated by numerous minute pores arranged, for the most
part, transversely near the adapical suture. This extremely
specialized, perhaps degenerate, condition must have been derived
phylogenetically from a more normal biporous state, and there is
every reason to expect that such a change would be repeated in
ontogeny. The features in which the podial pores of Pygastrides are
aberrant all point towards a Fibulariid modification more than to any
other.

I therefore incline strongly to the opinion that Pygastrides relictus
is an early phase in the post-larval ontogeny of some species of the
Fibulariide. The conclusion reached at the close of the previous
sectlon—that Pygastrides is a young stage of some form less remote
from the primitive Holectypoid condition than Hchinonéus—is
thus concordant with the result of this imdependent line of
argument.

DECADE VI.—VOL. V.—NO. XI. 32

498 Herbert L. Hawkins—Studies on the Echinoidea.

7. Tae MorpHocEeny or THE CriyprasTRoID PerienatHic GIRDLE.
There are two strikingly different types of girdle-structure in the
_ Clypeastroida. In the Fibulariide, Laganidée, and Scutellidz the
‘‘auricles”’ are situated on the proximal interambulacral plates.
In the rest more normal paired processes rise from the proximal
ambulacrals. In one respect, however, there is a resemblance
between these different structures; there is in all a strong tendency
for the prominences to converge towards the interradii. In the
Clypeastride the great development of the proximal ambulacrals,
which often meet across the interambulacral, makes such a tendency
possible without a dissociation of the processes from their normal
foundations. But in the three families named above the proximal
interambulacrals are present in unusually large development on the
peristomial margin, so that no appreciable convergence of the
processes would be possible if they remained on the ambulacrals.

H. L. Clark has proved that the apparently single interradial _
‘“‘auricles”’ of the Fibulariid type are in reality double in origin and
intimate structure—they are, in fact, dislocated processes which
have carried their attempt at interradial convergence to the extreme
limit. In the preceding paper of this series I showed how both
types of Clypeastroid girdle could be derived from the Holectypoid
type. Pygastrides, if its ascription to the Fibulariide is correct,
gives an ontogenetic stage in the migration of the processes from
the ambulacra to the interambulacra. The obscurity of Lovén’s
figure in this respect is unfortunate, but it i-, sufficiently intelligible
to show that the processes are as much on the interambulacra as on
the ambulacra. Pl. XVII, Figs. 7a, 6, c¢, show in a diagrammatic
fashion the possible stages through which this change might be
brought about. As to the persistence of ax interradial element
(ridge) carrying the protractor muscles there is, at present, no
evidence in either direction.

Pygastrides affords a valuable simplification to the problem of the
derivation of the Clypeastroid girdle from the Holectypoid. Granting
the very near relationship between the Clypeastroida and Discovdes,
the difference between their perignathic structure is somewhat
embarrassing. But if they pass through a Pygastrides-phase, which
is simpler in some respects even than that of Pygaster, the girdles of
the Fibulariid and Clypeastrid patterns need not be encumbered by
the massive false-ridges of Discoides. The ontogenetic repetition
preserves the essentials, and entirely leaves out the individual
specializations of the ancestral adults.

In this respect it is noteworthy that both Pygastrides and the
young Hehinonéus are entirely without interradial ridges. In the
case of the latter, the protractor muscles are fixed to the free edges
of the proximal interambulacrals; these being, so far as appears,
quite unmodified as special muscle-supports. In the fossil
Holectypoida, as I have shown in this series of papers, there is
always some small relic of an interradial ridge on the proximal
interambulacrals, minute though these plates usually are. It may
well be that the absence of these structures in the two young stages
is due solely to their youth—they never appear in the edentulous

Herbert L. Hawkins—Studies on the Echinoidea. 499

Echinonéus, but at least the muscle scars develop later in
Echinocyamus. In the Clypeastride, again, no interradial elements
occur, the protractor muscles finding attachment on the processes
themselves.

The Fibulariide and Laganide are certainly less specialized in
most characters than the Clypeastride. It is therefore strange to
find the fused interambulacral processes—a highly specialized
condition—occurring in the former groups, while more typically
Holectypoid qualities are preserved in the latter. But if the
theoretical structure of the ‘‘auricle’’ of Hehinocyamus given on
Pl. XVII, Fig. 7c, is in any Way correct, that type of girdle is
more closely akin to the Holectypoid (especially to the Discoidiid)
type than the ridgeless girdle of Clypeaster. The two types of
Clypeastroid girdle must, however, mark two distinct and divergent
lines of descent; in one all structures become ultimately inter-
ambulacral, in the other ambulacral, in position. Both types differ
from the true Holectypoid, and it is premature to ascribe greater or
less specialization to either.

8. Toe Bearing or PyeasTrrmpes on Post-Hoiecrypoin PHyLoGEeny.

It will be realized from the foregoing descriptions and arguments
that Pygastrides is in most respects an Holectypoid, in many a
Pygasterid, in some a Discoidiid, and is probably the young of
a primitive Clypeastroid. Of the young Zchinonéus of similar size
it may with equal j tice be said that it is in most respects
an Holectypoid, in many a Pyrinid (or Conulid), and in some
a Discoidiid. The young Abatus at a smaller size may be said to be
Pygasterid in apical and periproctal characters, Pyrinid in shape, but
already Spatangid iu coronal plating. The last-named form is
evidently so accelerated in its ontogeny that no certain conclusions
can be drawn without more evidence. The two others are more
restrained in development, and their evidence on the phylogeny of
their adults is intelligible and conclusive. Of Hchinonéus and its
relatives I hope to treat in the near future, but it will suffice here to
incorporate the evidence of Pygastrides into the scheme of post-
Holectypoid evolution.

Paleontological and morphological study link the Clypeastroida
inseparably with the Holectypoida. The peculiar distribution of
the madreporic pores and the development of internal supports
associate them more particularly with the Discoidiine. Whether
Lchinocyamus and its relatives be primitive or degenerate, they are
certainly the simplest of the Clypeastroida. Pygastrides, if the
above interpretation of its nature is correct, adds a conclusive
ontogenetic proof of the near alliance between the two orders, and
suggests that the Fibulariide are truly primitive. Almost the only
features in which Pygastrides differs from a true Holectypoid consist
in the omission of certain structures, most of which are obsolescent
in the Holectypoida themselves.

9. Summary.
Pygastrides relictus, Lovén, is believed to be an early post-larval
stage in the development of some Irregular Echinoid. Reasons are

\

500 H. G. Smith—Basic Intrusions -

given for the belief that this Echinoid is probably a Clypeastroid,
and one of the Fibulariide. In view of its undoubted resemblance
to the Holectypoida, particularly to the Pygasteridz and Discoidiide,
Pygastrides is regarded as affording ontogenetic evidence of the
phyletic connection of the Clypeastroida and Holectypoida through
the Discoidiidee.

EXPLANATION OF oben XVII.

Fie.

1.—External view of the peristomial region of Pygastrides relictus, much
magnified (after Lovén).

2.—Internal view of the same region. The perignathic processes are nase
away in areas Jb, IVa, and Va.

3.—Proximal end of an ambulacrum of a Scutellid (Hncope), showing ie
single, perradial, deeply sunken spheridial pit (after Lovén)..

4.—Plan of the peristomial region of the corona of Hchinocyamus, internal
surface. The ambulacra are stippled. (Reversed and modified from
Lovén so as to compare with Fig. 2

5.—Adapical view of young Abatus cavernosus, 2-5mm. in diameter (after
Mortensen). The periproct is Plesiechinoid in position, and the apical
system Pygasterid in character.

6.—Internal view of the peristomial region of young Echinonéus, 4:19 mm.
- long (after Westergren). Note the reduced proximal plates and the
progressive ambulacral structure.

7.—Diagrams to suggest the possible origin of the Fibulariid Ginaiale’
The ambulacra are stippled. (a) Disjunct processes of Pygaster or
Pygastrides. Retractor muscles single, protractors on edge of proximal
interambulacral plate, with or without a rudimentary ridge. (6) Pro-
cesses meeting across interradius, and based upon the interambulacral
plate. Retractor muscles double, protractors on a raised (Holectypoid)
ridge. (c) Auricle of Hchinocyamus. The dotted lines indicate its
possible origin from stage 6.

IV.—Txe Basic Inrrustons East or Gettr Hirt, Rapnorsuire.

By H. G. Smiru, A.R.C.S., B.Sc:, F.G.S. ; with three analyses by
J. H. WILLIAMS.

(PLATES XVIII AND XIX.)

URING the last few years I have spent a considerable amount of

time studying the geology of the country east of Llandrindod,

but much still remains to be done, and the present paper merely

embodies a few of the points which seem ‘to be satisfactorily

established with regard to a small portion of the area. Three

distinct types of igneous rocks are recognized, and some facts and
ideas with regard to each are put for ward.

THE OLIVINE oe
Forming part of the N.N.E.-S.8.W. ridge east of Tyn-y-coed, and
best exposed in a quarry at its southern end, is a dark-coloured,
almost black, fine-grained igneous rock, which, in the absence of any
published descriptions,’ calls for some comment.,, The same type
also occurs about a mile to the north in the neighbourhood of Bwlch-

' Dr. Harker (Presidential Address to the Geological Society, Q.J.G.S.,
pt. i, 1917) mentions the existence of basalts in the Wells country, and
considers them to be extrusive,

GEOL. MAG. 1918. PLATE XVII.

yy~ac! (Ge ¢) ©
aye vines Z
SOT

Post-LARVAL STAGES IN CERTAIN IRREGULAR ECHINOIDEA.

>

ee)

Last of Gelli Hill, Radnorshire. a axon

llwyn, notably forming a conspicuous elevation west of the Bog
Wood.’ The specific gravity of the fresh variety is 2°86.

Examined microscopically, the rock is seen to be a typical
olivine basalt with remarkably fresh felspar and augite. The most
abundant constituent is the lath-shaped felspar, the crystals of
which reach a maximum of 1:4 mm.; there is no indication of two
generations. In some cases there is an aggregation into groups,
producing a structure with some resemblance to glomero-porphyritic.
The refractive index is well above that of Canada balsam, and
some individuals are partially replaced by a green substance,
probably clinozoisite. Between crossed nicols the felspar exhibits
the usual first order colours and lamellar twinning, and the angle ot
extinction is rather high. Some zoning is to be seen. The refractive
index and extinctions indicate a composition approximating to that
of labradorite.

A very pale, almost colourless, granular augite occurs between the
felspars. It has the usual relief; a few fragments exhibit the
rectangular cleavages, and it is commonly quite fresh. The polariza-
tion colours are of the first and second orders.

There are occasional pseudomorphs, maximum dimension 1:2 mm.,
preserved in some cases in a pleochroic serpentine, elsewhere in
a mixture of serpentine and calcite or quartz. Their shape and
structure leave no doubt as to their derivation; they were originally
olivine.

Ilmenite occurs moulded on the felspar; it is sometimes fresh, but
the numerous grains of sphene present in the rock have probably
resulted from its alteration.

A devitrified glass occurs as a groundmass. Some vesicles are
filled with similar material, which exhibits a system of black crosses
in polarized light. One vesicle is occupied by an almost isotropic
glass with a curious cellular structure, the cells in places near the
margin elongating to tubes with approximately radial disposition.
This structure appears to be a record of the infilling of the vesicle,
the various streams of viscous magma having failed to amalgamate
after entry.

The observed occurrences of the basalt are all at or near a junction
where fossiliferous felspathic ashes rest on shales with tuning-fork
graptolites; hence the obvious conclusion that this rock represents
the first product of the extrusive igneous activity responsible for the
thick overlying ashes. But in spite of the fact that no metamorphic
phenomena have yet been observed, its intrusive character is still
considered to be a possibility. An Ordovician flow of this character
would be absolutely unique in the igneous history of Wales,’ and
the rock is remarkably fresh. On this question of possible intrusion
the suggestion made by Professor Watts? that the area of Tertiary
igneous activity outlined by Dr. Harker* may have to be extended
to the south has a possible application to this locality.

1 W. G. Fearnsides, Geology in the Field, 1910, p. 801.
2 Proc. Geol. Assoc., vol. xix, p. 179, 1905.
> Tertiary Igneous Rocks of Skye (Mem. Geol. Surv.), 1904, p. 3.

502 HA. G. Smith—Basic Intrusions

THe Drasase.

This Ape cree an imposing show on, the. ‘eiaanale One sill
(aligned with the Castle Bank intrusion described by, Mr. Woods’)
commences just north of Camnant Brook, runs north-east. between
Blaenkerry and Garn-fach, turns due north, and is continued on the
eastern side of Gelli Hill to disappear under the ashes near the Bog,
a distance of about two miles. The Llanvirn Shales are in contact
throughout most of this distance. Another intrusion is exposed
north of Frank’s Bridge. It runs N.N.E. for about a mile and stops
short before reaching the River Edw. The same line is continued on
the other side of the river at Graig-fawr, exposed as a sill dipping
west, running just on the western “side of the farm, and dying away
in, the vicinity of Llanwefr Pool. The northern part of the sill is
shifted to the east by a dip fault. A shorter intrusion with the same
trend is found west of Pye Corner, and, finally, a parallel sill runs
from Cwm-maerdy to the Edw south of Pye Corner, but a portion of
the sill is shifted to the east by trough faulting. The behaviour of
some of these intrusions on approaching the rivers suggests that the
serrated upper edges of the sills have not yet been obliterated, and
the rivers have selected those places where the sinuous edge makes
a downward bend.

The rock is medium-grained with a general. erconishy tinge, showing
a pale-grey network ona black background.

In thin section the rock is seen to be made up principally of males
brown augite and lath-shaped felspars related ophitically. No fresh
specimens have been obtained, and in all the sections examined the
felspar is more or less decomposed; but as far as can be determined
the refractive index is never high enough for labradorite, and this
impression is supported by the symmetrical extinction angles of the
albite lamelle; the maximum value obtained is 16°, and it is
suggested that ‘the felspar is andesine. Pericline twinning is rare,
and. zoning has not been observed.

The augite varies from colourless to a pale brown. It has the
usual refractive index and cleavages, and alters, as a rule, to chlorite,
which polarizes in ultra-blue or first order grey, but in one séction
a brown amphibole represents an intermediate stage in the alteration.
There is an occasional suggestion of pleochroism. ‘The polarization
colours are of the first and second orders, and twinning, though seen,
is rare; the double refraction is positive. The individuals polarizing
in very low colours are invariably found to be approximately
perpendicular to an optie axis, and for this reason it is considered
that the fresh pyroxene is exclusively monoclinic. .There are,
however, some pseudomorphs which show good cleavage, polarize in
bright colours, and extinguish as a single unit which may be altered
hypersthene.. Some of the pseudomorphs suggest derivation from
olivine, but proof is wanting:

Another constituent locally abundant is ilmenite. “Ip aeecnedl
shows the characteristic white alteration product and is moulded on
the felspar and augite. A few idiomorphic crystals of sphene

1 Q.J.G.8., vol. 1, p. 576, 1894.

PLATE XVIII.

GEOL. MAG. 1918.

4
Ue

Bastc INTRUSIONS IN RADNORSHIREI

East of Gellt Hill, Radnorshire. 503

embedded in chlorite are possibly the result of the further alteration
of this mineral. Acicular apatite is present in small quantity.

The amount of metamorphism effected by the diabase is never
great, the most striking result being a rock resembling a spilosite,
produced in consequence of the alteration of the shales which almost
invariably occur at the contact. At one point, however, in the
brook just south of Pye Corner the contact rock is a limestone
containing fossils which Dr. Morley Davies recognizes as Sérick-
landinia lirata (Sowerby), S. lens (Sowerby), Strophonella euglypha
(Sowerby), Atrypa sp., Encrinurus sp., and Halysites sp. his fauna
he considers to be sufficient to prove the Upper Llandovery age
of the sediment, and it therefore becomes a matter of extreme
importance to determine the relative ages of intrusion and limestone.

A specimen of the diabase from near the contact includes a patch
of calcite, which mineral is seen in thin section to be interstitial with
regard to the felspars. The latter are not more basic than in the
diabase remote from the limestone, but apatite is distinctly more
abundant.

The limestone varies from pale grey to black. In places it
exhibits some resemblance to a conglomerate, containing subangular
fragments of quartz. Occasionally on the bedding plane is seen
a spheroidal projection which, broken across, is not to be dis-
tinguished from the adjacent igneous rock, and similar igneous
material is interbedded with the limestone, sometimes with a layer
of crystallina calcite at the contact. Lenticles of calcite occur
within the igneous material and patches of the igneous rock within
the limestone. Some pyrite occurs at and near the junction. A thin
section through one of the igneous spheres shows a diabase exactly
comparable with that of the adjacent sill; the felspars interlock in the
usual way and enclose angular patches of chlorite, and idiomorphic
crystals of apatite occur in the felspar. The margin of the sphere is
sharply defined; there is no transition into the limestone and, at this
contact, there is no evidence of recrystallization of the latter.

The part of the rock not obviously igneous in origin exhibits
features of considerable interest. Some portions of the sections are
made up of a network of felspar crystals related just as in the
igneous rock, but instead of interstitial augite or chlorite there is
crystalline calcite. Here again the felspars are not more basic than
in the diabase, and there is no support for the idea that calcareous
material has been incorporated by the felspars. Other crystals of
felspar appear to be isolated; they are sometimes idiomorphic, but
elsewhere are moulded on the calcite. Quartz, either as simple
individuals or as aggregates, occurs scattered through the rock as
subangular equidimensional grains, as extremely angular individuals
of various shapes, and as idiomorphic crystals. In one particularly
interesting case the felspar and quartz are intergrown to form
excellent micrographic structure. This example is sufficient to
demonstrate the igneous origin of some of the quartz in the lime-
stone and to render it extremely probable that no detrital quartz is
present in the rock.

There is no question as to the relative ages of the two rocks; the

504 H. G. Smith—Basic Intrusions

intrusion is certainly post-Llandovery. But there remains the
interesting question as to why the diabase has failed to cut through
_ the limestone. We are compelled to suppose that a magma exercises
a careful selection’ with regard to the rock invaded. In the case
here considered the diabase magma readily penetrated the shales,
but the overlying limestone presented an almost impassable barrier.
Igneous material was injected along the bedding planes, and pockets
containing the diabase were formed in consequence of a boring action
on the part of the magma, while the areas occupied by a network of
felspar with interstitial calcite resulted from the intrusion of
a felspathic portion of the magma into a locally fused limestone area
and subsequent crystallization of felspar followed by that of calcite.

All the evidence supports the theory that the diabase, when
intruded into its present position, was nearing the limit of its powers
of penetration. ‘The still existing serrations of the upper edges of
the sills, the failure to cut through the limestone, the very feeble
metamorphism, and the fact that the silicates do not incorporate any
of the calcium from the adjacent or containing limestone, aL point
in the same direction.

The conclusion here arrived at as to the age of the ajahaee is in
direct opposition to that put forward by Mr. Woods? as a. result of
his examination of the area to the south. He relies on the facts that.
‘nowhere do they (the diabases) pierce the Silurian beds”’, and that
at ‘‘the section exposed in the quarry next Pen-cerig Lake, where
the diabase is seen in contact with both Llandeilo shales and the
Llandovery beds, the former are metamorphosed, the latter quite
unaltered’”’. But we have seen reason to suppose that failure to cut
through a sediment is no proof that intrusion took place before that
rock was laid down, and it follows from the facts put forward that
striking metamor phic effects are not to be expected.

If the post-Llandovery date of the diabase is accepted, then these
intrusions are brought into, line with those of the Shelve area, where
Professor Watts* has shown that the dolerites ‘‘come into ‘contact
with and somewhat alter the Pentamerus limestones’’.

Professor Fearnsides‘* concludes that the andesitic dolerites of
Arenig ‘‘are of the same general age”. .

Dr. “Harker,® under the impression that the cleavage and plication
of the strata of Eastern Carnarvonshire were developed i in pre-Silurian
times, assigned a Bala age to the diabases of that area, but Professor
Fearnsides® points out that ‘‘with increase of knowledge the
supposed gap in the continuity of sedimentation has been filled up,
and now a Post-Silurian date for the cleavage is generally accepted”’.

It appears, then, that this post-Llandovery intrusion of diabase or

' This power of selection is implied, by Professor Watts in his description of
the intrusions of the Shelve area Cit Geol. Assoc., vol. xiii, p. 342, 1894).
2 Loe. cit., p. 577.
> Loe. cit., pp. 339-40.
. Q.J.G.S., vol. lxi, p. 631, 1905.
° Bala Volcanic Series, 1889, p. 76.
® Geology in the Field, 1910, p. 803.

GEOL. MAG. 1918. PLATE XIX.

DIABASE INTRUDED INTO LLANDOVERY LIMESTONE, River Epw,
RADNORSHIRE. X 14,

East of Gelli Hill, Radnorshire. 505

dolerite is a fact of some considerable importance in the geology of
Wales and Shropshire.

Tur Gran-orr Type.

At Glan-oer is exposed a fine-grained igneous rock, dominantly
pale grey, but with small black specks and larger whitish spots.
The same type is exposed in the quarry between Little Nant and
Graig-fawr, also in a dyke running N.W.-S.E. from the ford in the
Nant Brook below Hendy Bank to a point south-west of Llanwefr
Pool. The specific gravity is 2°69.

In thin section the rock is seen to be made up largely of a felted
mass of felspar laths with somewhat ragged outlines. ‘They are very
constant in length, averaging about 0°‘7mm. Alteration has gone on
to a considerable extent, but they can be seen to polarize in first order
colours and to exhibit lamellar twinning. Symmetrical extinction
angles are always low, the maximum value observed being 12°; the
.felspar must approximate to oligoclase in composition. Another
conspicuous constituent is a pale-green alteration product which is
sometimes moulded on the felspars; the relief is not great, but the
refractive index is distinctly higher than that of Canada balsam ;
polarization is first order grey and is of the aggregate character.
There is an occasional suggestion of olivine in the shape of the
pseudomorphs, and one particular case (1-2 mm. in length) places the
matter beyond doubt; the substance is serpentine, and is the result
of the alteration of olivine, almost certainly a variety poor in iron.
It is possible that some of the felspar crystallized before the olivine,
though the moulding of the serpentine on the felspar may be due to
the expansion consequent on the alteration. In this connexion,
though, it must be borne in mind that Professor Watts,’ in dealing
with the olivine-dolerite dykes of Antrim, has described a case
where the felspar crystallized before the olivine. Some varieties of
the allivalite of Dr. Harker? also exhibit a similar sequence of
crystallization. In that rock, however, the felspar is anorthite.

Another interesting constituent is a pale-brown augite. This
mineral is totally absent from some of the sections, and even in the
case of those in which it occurs the distribution is somewhat
eccentric. It is found in spots only large enough to enclose, perhaps,
a score of felspar laths. When altered, it produces a cloudy
aggregate containing much calcite; this is responsible for the whitish
spots visible to the naked eye. Other constituents are apatite,
fairly plentiful secondary sphene, and pyrite.

The remaining mineral is clear and fresh, with a refractive index
approximating to that of Canada balsam; it polarizes in first order
grey with occasional yellow. Careful search resulted in the
discovery of a definite cleavage, lamellar twinning, and the fact that
the refractive index is distinctly below that of Canada balsam. The
mineral is biaxial and the birefringence is positive. It is undoubtedly
albite. Twin lamelle run interruptedly from one felspar to the
other, though the angle of extinction changes. It is not possible at

1 Guide to Rocks and Fossils (Geol. Surv. Ireland, 1895, p. 78).
2 Petrology for Students, 4th ed., 1908, p. 103.

506 A. G. Smith—Basic Intrusions, Radnorshire.

present to say definitely whether the albite is magmatic in origin or
is the result of weathering.

This rock presents some points of resemblance to the Skomerite
and Marloesite of Dr. Thomas,’ but the evidence available suggests
that it is newer than the Lower Arenig, to which the Skomer
Volcanic Series is assigned.

ANALYSES BY J. H. WILLIAMS.
1. OLIVINE BASALT.

SiO» 48-66
Ti Os 2-23
Als O3 15-76
Fee Oz 2-66
FeO 8-16
MnO ; 0-14
(Ni Co) O 0-03
Ba O ‘ none
Sr O 0-16
CaO 10-90
MgO 5:68
K,O 0:05
Naz O 1-25
Li, O ; 3 none
He O at 105° C. : 0-70
He O above 105° C. 8-04
Po Os 0-22
S Os 0-43
C Oz 0-20
FE traces ?
Cl . - traces
Total 100-27
2. DIABASE.
SiO. 45-82
Ti O2 1-99
Als Os 16-49
Fe, O3 1:80
FeO 7-48
MnO 0-15
(NiCo) O none
Ba O none
Sr O traces
CaO 8:79
MgO 8-95
K.0 0-35
Nag O 2-82
Lig O none
H.O helo 100° C. 0-50
He O above 100° C. 4-89
P. Os 0-18
SOs traces
C Oz 0-04
Bike traces
Cl traces
Total 100-25

1 Q.J.G.S., vol. Ixvii, pp. 196-201, 1911.

Dr. F. A. Bather—Notes on Yunnan Cystidea, 507

8. THE GLAN-OER TYPE.

Si Os s ‘ ; ‘ 3 , . 60-76
Ti Os ; 3 =) : ; i : 2-10
AleOg . R 3 , 4 a GO
Fes O3 5 5 5 a . . 5 0-86
FeO ‘ f 5 : F : ; 6-90
MnO z : : ‘ : : 4 0-11
(NiCo) O 5 ; ‘ ; : ; none
Ba O F s : ; ‘ : : none
Sr O { ; : ‘ E ‘ . traces
CaO 4 : : ; f . : 3-55
MgO : : 4 : : f . 8-02
K20O 5 4 : 4 : f 5 0-81
Nag O . 5 . 5 A a O 3°78
Li, O - 3 : 3 s ; . traces?
He O below 100°C. . ; ; : : 0-41
H.O above 100°C. . ; : 2 : 5-33
P2 Os : ; : : 4 s 5 0-26
Fe Se : ' 4 ; : : : 0-41
C Oz A é : : : d : 0-61
1 : : g : ; 5 : none
Gl . y : : : ; ‘ . traces
Ivor 4 i . 99-92

In conclusion, I wish to express my indebtedness to Miss
Chamberlain, who placed her notes and maps at my disposal, to
Dr. Morley Davies, who identified the fossils, and to Professor Watts,
who looked through the proofs and made valuable suggestions.

_EXPLANATION OF PLATES XVIII AND XIX.
PLATE XVIII.
Fic. 1.—Augite moulded on felspar, N. of Llanwefr Pool. (Diabase.) x 16.
,, 2.—Ilmenite moulded on felspar and augite, Graig-fawr. (Diabase.)
x 305.
», 38.-—Olivine basalt, EH. of Little Wern. x 27.
,, 4.—Pseudomorph after olivine, S.W. of Llanwefr Pool. (Glan-oer type.)
STs
», 5.—Ophitic structure, Glan-oer. (Glan-oer type.) x 34.
PLATE XIX.

Fies. 1-3.—Specimens of diabase intruded into Llandovery Limestone from
River Edw, 8. of Pye Corner, Radnorshire. x 1% nat. size.

V.—Norres on Yunnan Cysripgea. I. Szvocysris anp OvocyYsrTIs.
By F. A. BATHER, D.Sc., F.R.S.
(Published by permission of the Trustees of the British Museum.)

EFORE returning to Calcutta the specimens described in his
memoir ‘‘Ordoyician and Silurian Fossils from Yun-nan”’
(1917, Paleont. Ind., n.s., vol. VI, Mem. 3), Dr. F. R. Cowper
teed very kindly lent to the Geological Department of the British
Museum the figured cystids, in order that plaster casts of them
might be made and kept there for reference. This was done, and
a set of the casts was also furnished by the Department to the
Sedgwick Museum, Cambridge. While preparing the specimens for
the moulder, I had the opportunity of studying them with some

508 Dr. F. A. Bather—Notes on Yunnan Cystidea.

eare. Although Dr. Reed has published good figures, drawn with
Mr. T. A. Brock’s usual exactitude, and descriptions, on the fulness
of which he will perhaps allow me to compliment him, neverthe-
less the notes made by me, when still unacquainted with his
valuable work or with the views therein expressed, do contain
supplementary matter, which it seems better to publish now rather
than to reserve for some revision in an uncertain future.
ORIENTATION.

To avoid confusion, it is necessary to explain that the terminology
and orientation here employed are the same as those used by me in
describing the cystids from the Northern Shan States (1906,
Paleont. Ind., n.s., vol. II, Mem. 3), also in Lankester’s ‘‘ Treatise
on Zoology”’ (1900), and elsewhere. As regards the terminology of
the various parts and organs, Dr. Reed and I are in general agree-
ment; but the orientation adopted by Dr. Reed is unfamiliar. To

; Aas

bbe
antervir

Fic. 1.—A diagram of the adoral face of a simple five-rayed Pelmatozoon,
showing peristome, hydropore, gonopore, and periproct; the orientation
indicated according to F. R. Cowper Reed.

Fic. 2.—The same ; the orientation indicated according to F. A. Bather.

meet the difficulty that I found in interpreting it, Dr. Reed has

kindly marked his main lines on the accompanying diagrams

(figs. 1 and 3), beside which my own scheme (figs. 2 and 4) is placed

for comparison. In both cases the ‘vertical axis’ runs from the

oral centre (my ‘oral pole’) to the centre of the base (my ‘apical
pole’), and all the diagrams are viewed from above the oral pole.
From his diagrams and letters it appears that the basis of

Dr. Reed’s scheme is the ‘ sagittal plane’, which he takes as passing

through the vertical axis in the direction of the mouth-extension,

or, in a normal five-rayed form, between the pair of rays enclosing
the hydropore [ ‘ bivium’ | and the remaining three rays [ ‘trivium’ ].

The ‘antero-posterior plane’ of Dr. Reed cuts the sagittal plane at

right angles on the vertical axis; the anterior face of the theca is

that on which the hydropore lies, and (usually) the anus.

Dr. F. A. Bather—Notes on Yunnan Cystidea. 509

It is not necessary to enquire whether this scheme is used quite
consistently by Dr. Reed; it is doubtful whether it could be. Nor
need one do more than point out that Dr. Reed strays no less from
general custom in his use of the terms ‘pole’, ‘meridian’, ‘right’
and ‘left’.

Unfortunately Dr. Reed believes himself to have been following
the chapters in the ‘‘Treatise on Zoology” as his ‘authority’, a
compliment which is so effective a criticism of their lucidity that it
is necessary to make their scheme plainer in so far as it applies to
Cystidea.

A pole is a point at which an imaginary axis cuts the circum-
ference of the theca. .

The oral pole coin ey with the centre of the peristome (wide

infra).

posterior anterior
; fori live \ ;
sagilial \ |
\

—

un peristomie
julane

proslerior

Fic, 3.—A diagram of the adoral face of Sinocystis manswyi, after Reed, 1917,
jolle IOUT atex TU; the orientation according to Reed. x 4.

Fic. 4. —The same ; the orientation according to Bather. The evidence for
the ‘‘ primitive sagittal plane’’ is given in the notes on S. loczyi (part II,
fig. 8).

The apical pole coincides with the centre of the basal attachment,
or with the centre of the system of plates in that region.

A specialized apical system of plates comparable with that of
Crinoidea and Kchinoidea has rarely been attained in Cystidea.

The vertical axis cuts the theca at the oral and apical poles.

The region of the thecal surface surrounding the oral pole is the
adoral face.

The region surrounding the apical pole is the adapical face.

The thecal openings are normally four: the peristome, often
ealled the ‘mouth’, but that organ, strictly speaking, lay within it
and may have occupied but a small part of the peristomial area; the
periproct, often called the ‘anus’, but that organ lay within it and
occupied only a part of the periproctal area; the hydropore, some-
times in the form of a ‘madreporite’, usually lying close to the

510 Dr. F. A. Bather—Notes on Yunnan Cystidea.

peristome; the gonopore is the name frequently applied to the
‘fourth opening’ on the assumption that through it the gonads were
emitted, but Jaekel calls it the ‘parietal pore’ on the assumption
that it was the opening of a persistent parietal canal—the two
assumptions are by no means mutually exclusive. Primitively
these four openings lie in a straight line which probably indicates
the attachment of the dorsal vertical mesentery to the inner wall of
the theca; their order is peristome, hydropore, gonopore, periproct.

In this series the peristome (mouth) is anterior; the periproct
(anus) is posterior. The line joining these two is the oro-anal axis.

The theca being placed with its oral pole uppermost and with the
anus towards the observer, then the right and left of the theca
correspond with the right and left of the observer. In representations
of all Echinoderma, figures representing the adoral or adapical faces
should be placed on the paper so that the right side of the creature
is towards the right side of the page. Side-views of Pelmatozoa
should have the adoral end uppermost.

The antero-posterior plane or anal plane passes through the oro-
anal axis and the vertical axis. A line drawn in this plane and
bisecting the vertical axis at right angles would be the antero-
posterior axis. This does not coincide with the oro-anal axis, and
the concept is rarely required.

As regards the sagittal plane there is perhaps room for hesitation.
When the thecal openings all he in the antero-posterior plane, then
that plane is the sagittal plane, as it would be in any symmetrical
animal. The plane at right angles to it and passing through the
vertical axis 1s then the transversal plane (T'ext-fig. 2).

In many cystid genera asymmetry is manifested in a migration of
the anus and in a correlated or an independent shifting of the
gonopore. The oral pole being regarded as fixed, then it appears
that the hydropore (or madreporite) ‘undergoes less lateral change of
position than the other organs. The plane through the vertical
axis and the hydropore may therefore not coincide with the antero-
posterior plane; it needs a distinct name, and I have called it the
M plane (= madreporite plane) (Text-fig. 4).

It seems best to limit the term ‘sagittal’ to its primitive
morphological use, available only for outwardly symmetrical or
almost symmetrical forms; and for asymmetrical forms to use the
terms ‘anal plane’ and ‘M plane’. When a sagittal plane cannot be
fixed, then it is inaccurate to use the term ‘transversal’, and another
term (should one be thought necessary) must be found for the plane
passing through the vertical axis and the peristomial extension,
which plane in pentamerous Pelmatozoa separates the bivium
(radii C D) from the trivium (radii E A B); it may be called the
peristome plane. As a rule, but not always, the plane which
Dr. Reed has termed ‘sagittal’ corresponds roughly to this
peristome plane. In Pelmatozoa the peristome plane usually
hes approximately at right angles to the M plane, but this arrange-
ment is not inevitable. In the Spatangoid sea-urchins the peristome
plane separates the bivium (A B) from the trivium (C D E)—quite
a different plan; theoretically it forms an angle of 54° with the

Dr, F, A. Bather—Notes on Yunnan Cystidea. 511

M plane, and the plane (radius D; interradius A B) to which it is
at right angles is the plane of test-elongation known as ‘ Loven’s
plane’ (see ‘‘ Treatise”, 1900, pp. 19-22, fig. xviii). Such facts as
these show that the peristome plane has been fashioned in different
groups in response to different adaptations, and that in each group it
is of later origin than the M plane and the anal plane, just as they
are, ex hypothest, later than the sagittal plane.

Sryocystis anpD Ovocysris.

About ninety specimens from the Ordovician limestones and
calcareous mudstones of Shih-tien (Reed’s rock-types g and h,
Coggin Brown’s beds 5 and da) are relatively large cystids belonging
to the family Spheronide of the Diploporita. Twenty-one of these,
being figured specimens, were studied by me and will here be
referred to by the numbers of the plate-figures, since they were
unprovided with any other reference-number. They are distributed
by Dr. Reed between his two new genera Sinocystis (S. loczyt, I, 1-8,
and S. yunnanensis, I, 9, 10, II, 1, 16: n.spp.) and Ovocystis
(O. mansuy?, n.sp., II, 2-11). They agree, however, in a number of
characters, which may be summarized as follows :—

Theea variable in shape but roughly ovate pyriform, tapering to
the base of attachment which may be prolonged as a_ short
unspecialized stalk; composed of numerous (100-600) irregular,
polygonal, stout plates, bearing conspicuous diplopores. Oral pole
approximately in the centre of the rounded summit of the theca.
Peristome extended approximately at right angles to the anal plane
(probably an elongate rectangular opening) with two short food-
grooves diverging at each end (one at each corner) and each ending
on a brachiole-facet (possibly more than one); mouth and epithecal
food-grooves with irregular cover-plates interlocking across the
middle line and apparently fixed. Periproct on the adoral face,
about half-way between oral pole and periphery, hexagonal or
pentagonal, with 6 or 5 covering valves. Hydropore slit-like, lying
slightly to left of anal plane, close to peristome. Gonopore
pentagonal to circular, on left of periproct.

The three species are well founded: they may be distinguished by
their diplopores, if by nothing else. S. yunnanensis is, no doubt, of
the same genus as Sinocystis loczyz; but why is Ovocystis mansuyt
separated? Examination of the generic diagnoses provided by
Dr. Reed reveals the following alleged differences.

The periproct of Svnocystis is hexagonal, of Ovocystis pentagonal.
This is really a point of no importance; but in any case the rule is
open to exception, for in O. mansuyz the outline seems to be
hexagonal in specimen I], 6.

The diplopores of Sznocystis are, it is said, covered by tubercles of
epistereom ; those of Ovocystis are not covered by epistereom. This
is a very doubtful point. In all three species there is a tendency for
the stereom immediately surrounding each pore-pair to be raised, so
as ultimately to form a sort of tubercle. In S. loczyi the pores open
on a rounded elevation surrounded in some cases by a faint moat.
This elevation may reach a height of 1:7 mm. above the test

512 Dr. F. A. Bather—Notes on Yunnan Cystidea.

(specimen I, 8), and as it grows upwards there is certainly a tendency
for the epistereom to block the pores, but I was unable to convince
myself that it ever actually succeeded (Text-fig. 5). In S. yunnanensis,
where the pore-pairs are more numerous than in S. loczy, they have,
for the sake of space, to assume a more regular arrangement, and so
the long axis of each elevation is on a line radiating from the umbo
of the plate; but they are not in continuous lines. At the umbo of
each plate the growth of the elevations is such that the whole
epistereom of the umbo is often raised into a kind of turret
surrounding a few diplopores. These turrets were only found
preserved on those regions of the theca from which the matrix had
not been weathered away; probably they had been worn down in
the other regions. On other parts of the plate there are sometimes -
elevations similar but subsidiary to that at the umbo (e.g. I, 1); in
some cases a plate with about five of these in a circlet round the
umbonal turret resembles a cidarid plate with its primary and
secondary tubercles. Excessive growth of epistereom, especially in
the turrets, may perhaps close the pores occasionally; but I could
not be any more sure that it did so in this species than in S. locayz.

hale MEE ae

—

5 6
Fie. 5.—Sinocystis loczyi: a group of tubercles bearing open diplopores, seen
from the side, on a fragment extracted from soft matrix accompanying
specimen I, 8. x #.
Fic. 6.—Sinocystis mansuyt: an elevation bearing a diplopore, seen from
above and from the side, on specimen II, 5. x §.
Fic. 7.—A root attached to the theca of Sinocystis mansuyi, II, 6, a little
above its base. x #.

In O. mansuy: the fairly numerous but irregularly distributed
diplopores appear in some cases (e.g. II, 2) to be sunk directly through
the test, without either elevation or ‘peripodium. This appearance
may, however, be due to wearing down; for in II, 8, each pore-pair
is surrounded by a slight elevation dying away into the test, and in
well-preserved tracts of II, 5 the elevation is still more definite and
rises higher between the pores of each pair so that the openings le
on its shoulders (Text-fig.6). In unworn tracts of II, 9, 10, and 11,
the elevation is relatively high and well-defined, and occasionally
suggests a tendency to be so directed that both openings face up-
wards, i.e. in an adoral direction (especially in II, 9). In this
species the epistereom does not grow up round the pores so strongly
as in S. yunnanensis or even S. loczyi, and there is never any
appearance of blocking.

Although I was unable to prove the closing of any diplopores in
these fossils, Dr. Reed presumably has satisfied himself that it does
occur in both his species of Sznocystis. If so, it should probably be
regarded as a character of old age, and not as diagnostic of a genus.
It is difficult to believe that the closing of true diplopores by

~]

Dr. F, A. Bather—WNotes on Yunnan Cystidea. 5138

epistereom can ever have been a normal character of the adult in any
species: the structures seem so clearly adapted for the passage of
some aérating organs (papule) through the test; and the very fact
that the epistereom does grow up in tubercles and turrets indicates
the constant outward extension of those organs. In opposition to.
this view, the only previous evidence of weight has been Professor
O. Jaekel’s account of a thin reticular layer covering diplopores in
a fragment of ‘‘ Calix sedgewicki’’ from Bussaco (1899, Stammes-
gesch. d. Pelmatozoen., p. 72), an observation as yet isolated and
unconfirmed (see, however, discussion of Zrematocystis in Part I11).

The last point of difference mentioned in Dr. Reed’s diagnoses is
thus expressed: Sznocystis, ‘‘ No food-grooves on surface”’; Ovocystis,
‘‘ Surface of theca provided with irregular shallow food-grooves
meandering between plates, with local traces of stronger meridional
and concentric or spiral grooves.’ It is, as previously stated, the
case that Srnocystis, no less than Ovocystis, has short epithecal
food-grooves leading from the corners of the peristome to the
brachiole-facets. But certainly it has no others, and that is what
Dr. Reed means. If Ovocystis has these meandering food-grooves in
addition, it differs in this respect not merely from Sznocystis but
from every pelmatozoon yet described, and is a remarkable form
indeed.

Unfortunately I was not acquainted with Dr. Reed’s observations
till some time after the specimens had been returned to Calcutta.
I had, however, carefully examined, under a binocular dissecting
microscope, the whole surface of the ten specimens lent to the
Museum, and it is difficult to believe that such unusual structures
could have escaped notice. I have subsequently examined the
plaster-casts carefully made by Mr. F. O. Barlow, and can see
between the plates nothing that suggests a food-groove. Dr. Reed
in his description (p. 8) certainly adds that the grooves are
‘‘obscure’’, but he also gives a fairly definite account of their
course. He distinguishes three kinds: (1) ‘‘shallow . . . grooves
irregularly meandering along the suture-lines . . . and frequently
uniting’’?; (2) ‘‘one or more stronger sinuous longitudinal trunks
running meridionally down anterior face” [= posterior side];
(3) ‘fone or more concentric or obscurely spiral sinuous trunks on
the posterior [= anterior] face in the lower third.” He figures no
details of these grooves, and not one of Mr. Brock’s enlarged
drawings of the surface shows the smallest trace of them. Only
fig. 5 on pl. Il, which represents a theca with weathered and
imperfectly preserved surface, is said to show ‘‘traces of spiral
grooves’’ on the ‘‘ posterior side’”’. Actually the view is of the right
side, the theca being compressed in the anal plane, and the hydropore
lying under a prominence shown at the top of the figure about 1 cm.
to left of the median line. The post-mortem compression of the
theca has pushed the greater part of this right side in, so that there
is a sharp bend or crack down the anterior edge (right hand of
figure); and on the upper posterior edge (left of figure) the plates
are pushed slightly under those of the other and less compressed
half of the theca. The depression thus produced is continued as an

DECADE VI.—VOL. V.—NO. XI. 33

514 Dr. F. A. Bather—Notes on Yunnan Cystidea.

irregular curved groove across the right side of the theca in its lower
third, and this is clearly (perhaps too clearly) shown passing across
the drawing. The groove was interpreted, with the specimen before
me, as evidence of slight folding accentuated by weathering; some
- fainter folds, also the result of post-mortem compression, are obscurely
indicated below this main groove, and are brought out in the drawing.
If this is all that Dr. Reed has to offer in support of his ‘food-
grooves’, he must not be surprised if their existence is denied.
Grooves and folds just as clear are shown in specimens of Sznocystis
(see pl. I, figs. 6 and 7), a genus in which such ‘food-grooves’ are
rightly said to be non-existent.

Clear and undoubted evidence is required, for a priors arguments
are certainly opposed to Dr. Reed’s interpretation. Dr. Reed |
- compares the alleged food-grooves to those of Fungocystis, Pyrocystis
pirum (apud Jaekel), and Gomphocystis. In the two former the food-
grooves, as usual in Glyptospheride, cut across the thecal plates and
do not follow their sutures. In Gomphocystis certain thecal plates
have assumed a more definite arrangement as floor-plates of the
grooves, which follow a spiral but quite definite course wholly unlike
that described for Ovocystis by Dr. Reed. In all three genera, as
indeed in all Diploporita, the epithecal food-grooves end on exothecal
brachioles, of which the facets af any rate are visible. The cover-
plates of the grooves are not preserved in all specimens of Diploporita,
though the notches for their reception may often be detected; but in
forms with such solid and well-preserved cover-plates as Sinocystes
and Ovocystis, some traces of them would certainly be found on any
extensions of the subvective system that might occur. No traces of
cover-plates are visible on the alleged extensions in Ovocystis.
Finally in all Pelmatozoa the food-grooves lead to the peristome ;
and this arrangement is conspicuous in all Diploporita. In Ovocystis
mansuyt, as in both species of Sinocystis, there is a particularly
evident subvective system, with brachiole-facets and strong cover-
plates. There is not the smallest trace of any extension from this
compact system over the general surface of the theca, nor has
Dr. Reed ventured to describe or portray any connection between
this system and his vaguely meandering, or longitudinal meridional,
or concentric spiral grooves.

The simple fact is that the thecal plates of Ovocystis mansuy? are,
as Dr. Reed puts it, ‘‘thick swollen”; in other words, the suture-
lines are depressed. But there is no evidence that extensions of the
subvective or any other system passed along these depressions.

Many specimens of O. mansuyt (e.g. II, 8, 4, 6, 8, 10) are
distinguished from all [?] the specimens of Sinocystes by bearing on
some of their thecal plates structures which Dr. Reed calls ‘‘ small
circular isolated raised cup-like pseudo-brachiole facets’’; and,
when the specimens were in my hands, being unable to discern any
other points of difference, I supposed in my ignorance that Dr. Reed
had based his genus to some extent on these appearances. Therefore,
though not in much doubt as to their true nature, I was led to
examine them with some care. This is fortunate, since Dr. Reed
seems undecided ‘‘ whether to interpret these structures as features

Dr. F. A. Bather—Notes on Yunnan Cystidea. 515

of classificatory importance or as individual peculiarities due to
accident or as resulting from some extraneous cause”. He is right
in regarding the last interpretation as the ‘‘most probable”; the
structures are in fact the root attachments of some other Pelmatozoon,
and similar appearances are familiar enough to those who have
studied Ordovician cystids in the field. In II, 3, there is a small
one near the base, and this, as drawn in fig. 3, has a circular lumen.
In II, 4, there is near the base a rather large one, 4 mm. high,
4-7 mm. wide at its summit, and 6°7 mm. wide where it rests on the
theca; it is divided by a stellate lumen into irregular pentameres.
By removing the thecal plate on which this rests and examining its
inner surface it is seen that the encrusting root covers several
diplopores. That the covering up of the diplopores took place
gradually as the root extended appears from a few incipient roots on
the better preserved face of the same specimen, for in them the pores
still pierce the outer extensions of the incrustation. This face of
the theca bears five such roots, and two of them, which also are
quite small, have a sub-pentagonal cup-like excavation, reminiscent
of the Liassic Cotylecrinus. Near the lower end of II, 6, there is a
relatively large root-base which rises sharply from the test like
a broken volcanic cone (Text-fig. 7); its diameter below is 8mm.,
and above about 4°5mm. In II, 8, a somewhat similar root covers
the anal pyramid. On the anterior face of II, 10, which is the less
flattened face and presumably lay upwards, there are three, perhaps
four, root-bases, more or less merged in the test. The object which
in II, 5, covers the hydropore (v. supra, p. 513, line 7 from end) may
or may not be such a root.

The preceding facts prove that the roots were independent of the
cystid on which they grew, that in some cases they must have
established themselves on the theca after the death of the cystid,
but that in other cases they settled on it and continued to grow, at
least for a time, during the life of the cystid: When in the last-
mentioned case the cystid deposited its own stereom round and
partly over the stereom of its unbidden guest, then a difficulty was
created for the modern paleontologist.

All the points of supposed difference between Ovocystis and
Sinocystis have now been discussed and shown to be non-existent or
unimportant. It follows that Ovocystis is a synonym of Sinocystis,
which now contains the three species S. loczyi, S. yunnanensis, and
S. mansuyt. The nomen nudum Sinocystis piroides Reed (in Coggin
Brown, 1913, Rec. Geol. Surv. India, xliii, p. 332) is said in the
1917 memoir (p. 60) to be a synonym of Pyrocystis(?) orientalis
Reed; it was provisionally attached to the larger of. the two
specimens from locality K 15/302.

Since Dr. Reed has not named a Genotype for Sinocystis, the
species S. Joczyz is hereby selected.

Before the systematic position of Sinocystis is discussed, further
notes on the specimens will be given.

516 Reviews— Work on Mesozoic Floras.

RAV LEW sS-

I.—Somr Recent Worx on Mesozoic Froras.

1. On He Creracrous Frora or Russtan Saxkwarin. By
A. Krysmrorovicn. Journ. of the Coll. of Sci. Imp. Univ. of
Tokyo, vol. xl, art. 8, pp. 73, with 15 text-figures, 1918.

2. Mesozorc Froras oF Queenstanp. By A. B. Warxom. Part I
continued: The Flora of the Ipswich and Walloon Series,
(¢) Filicales, ete. Queensland Geol. Surv. Publ., No. 257, 1917,
pp. 66, with 10 plates and 12 text-figures. Part I concluded:
(d) Ginkgoales, (e) Cycadophyta, (f) Coniferaies. Queensland
Geol. Survey Publ., No. 259, 1917, pp. 48, with 9 plates.

38. Tur Eartrer Mesozoic Froras or New ZEatanp. By EK. A.
Newett Arzer. New Zealand Geol. Survey Paleontological
Ball., No. 6, 1917, pp. 80, with 14 plates and 12 text-figures.

1. The Island of Sakhalin possesses a fossil flora, rich in species,
which has hitherto been regarded as exclusively of Miocene age.
Kryshtofovich—who recently visited the western coast of the
island, examining nearly 200 outcrops with plant remains—claims,
however, to have established that this so-called Miocene flora belongs
to several geological horizons, not only of the Tertiary period but
also of the Cretaceous. He points out that so-called ‘ Arcto-
Tertiary’ floras in other parts of the world might also repay thorough
revision.

The part of the Cretaceous of Sakhalin known before, and repre-
sented by marine deposits, has been hitherto considered as belonging
to the Senonian, and its thickness estimated at 3,500 feet. But the
present author’s work has indicated the presence of Turonian,
Cenomanian, and probably even older divisions of the Cretaceous,
thus making the total thickness at least 7,000 feet. He proposes
a Classification of these Cretaceous rocks, based on the plant remains.

2. The two memoirs by Walkom with which we are here
concerned form the conclusion of his study of the flora of the
Ipswich and Walloon Series, of which the first instalment appeared
in 1915 as Publication 252 of the Queensland Geological Survey.
Tt is pointed out that the results so far obtained indicate that the
flora of the Walloon Series is Jurassic, probably corresponding to the
Liassic or Lower Oolite of Europe, while the Ipswich Series is
Triassic, or possibly equivalent to the so-called Rhetic beds of various
areas.

3. The plant impressions discussed in Arber’s memoir upon the
Mesozoic Floras of New Zealand are derived from rocks whose age
ranges from Triasso-Ithetic to Neocomian. Jn the provinces of
Canterbury and Otago Rheetic floras occur. Jurassic floras are met
with in the provinces of Canterbury, and especially Southland,
while a Neocomian flora occurs in Auckland, but no evidence of an
undoubted Upper Jurassic flora has yet been met with. Prior to the
commencement of the work of which the results are recorded in the
present paper, there were only eleven valid records of Mesophytic
plants from New Zealand, but the author has been able to add

Reviews—Memorr of John Michell. oli

thirty-seven species to those already known. Of these at least
fourteen species are new.

Arber concludes from his examination of the fossil floras that
there is no evidence, at the time of writing, of any terrestrial
vegetation in New Zealand older than the Triasso-Rhetic, and he
considers that, on the known evidence, New Zealand did not form
any part of the Permo-Carboniferous continent of Gondwanaland,
although in Rheetic, and probably also in Jurassic times, New
Zealand and Tasmania were united with Australia as one large
connected land area. Professor Seward is inclined to recognize
a close alliance between the Mesozoic genus Linguifolium, which
occurs in New Zealand, and the genus Glossopteris, which
characterized the Gondwanaland flora, but Arber, in the present
paper, gives detailed reasons for maintaining the distinctness of these
two genera.

The flora of Waikato Heads, Auckland, is of particular interest as
being perhaps one of the oldest, in a geological sense, of the known
Neophytic floras. Professor Laurent, of Marseille, contributes
a description of two Angiosperms obtained from these beds, one of
which is fragmentary, while the other consists of leaves which he
refers to a new species of the genus Artocarpidium.

A.A,

Ji.—Memorr or Jonn Micuett. By Sir Arcurpatp Geinte, O.M.,
K.C.B., F.R.S. pp. 107. Cambridge University Press, 1918.

EOLOGISTS owe a considerable debt to Sir Archibald Geikie

for his contributions to the history of their science. That debt

is further increased by the issue of this memoir, dealing, as it does,

with the lfe and work of a man who, though little known at the

present day, held a position of no small note among his
contemporaries.

John Michell, to use an often-repeated phrase, was a man of parts;
he was one of those persons of wide interests and accomplishments
who adorned the front rank of scientific men in the eighteenth and
early nineteenth centuries, but who have, unhappily, been swept
away by the advance of modern progress and its accompanying
necessity for specialization. He was, of course, a classic and
mathematician, and in addition to his geological work he carried out
experiments in physics and devoted a considerable amount of time to
astronomical observations, which he performed with a reflecting
telescope made by his own hands.

He was elected to a Fellowship of Queen’s College, Cambridge, at
the age of 25, in the year 1749, and held a number of offices
in the University till 1762, when he was elected to the Woodwardian
Professorship of Geology. This office he only held for about two
years, when he was obliged to resign from it on the occasion of his
marriage. From this time onwards he held in succession the benefices
of Compton, Havant, and Thornhill, at the last of which he died in
the year 1795.

Being a man of a somewhat modest and retiring disposition he has

518 Reviews—Harly Man in America.

left little published work; his most important geological communica-
tion was his paper on earthquakes, which was read at five successive
meetings of the Royal Society in 1760, and which met with such
approval that he was shortly afterwards elected a Fellow. IJnaddition
to this work he spent much of his leisure time in geological excursions,
and in these obtained a wonderfully accurate idea of the correlation
of the strata of the south and east of England, based entirely on
lithological characters, which, fortunately, was put in writing by
one of his friends and has thus been preserved. He was a friend
of many of the chief men of science of his day and more especially
of Herschell and Cavendish, with both of whom he frequently
corresponded on scientific matters. It is on record that the first idea
of using the torsion balance as a means of determining the density of
the earth was suggested to Cavendish by Michell, who, indeed, made
such an apparatus, but not, however, one of sufficient delicacy for
the purpose, so that it-was left for Cavendish to carry the experiments
to a successful conclusion. His only other published work was
a small book on artificial magnets, which embodied much of the
experimental work he did while at Cambridge.

This memoir, written in the author’s accustomed literary style, is
eminently readable, and contains a very interesting account of this
little-known Woodwardian Professor.

Woe

I1{.—Recent Discovertes reLatine To Karty Man In America.
By Aves HrpnitKka. Smithsonian Institution, Bureau of American
Ethnology, Bull. 66, 1918, pp. 65, pls. xiv.

CCORDING to Dr. Hrdlicka there is still no evidence of really
fossil man in North America. He refers especially to the
human remains found in the asphalt of Rancho La Brea, California

(J. C. Merriam, Science, n.s., vol. xl, pp. 198-208, 1914), and to

those found with Pleistocene mammals at Vero, Florida (see Guot.

Mac., Dec. VI, Vol. IV, p. 4, 1917). The skeletons at Vero are

said to be undoubted inter aLSINGS, and the remains from La iiea also

appear to be those of a modern American Indian.

LVY.—American Fosstz Horses.

Eeumm or tHE Onicocenr, Miocenk, anp Priocrnn or Norra
America, IconocrapHic Typr Revision. By Henry Farrrimerp
Osporn. Mem. American Mus. Nat. Hist., n.s., vol. 11, pp. 1-217,
pls. i-liv, and 173 text-figures, 1918.

HE evolution of the horses in North America has long excited
wide interest, and has been much discussed in popular writings

as well as in scientific memoirs. ‘lhe statements of fact needed for
this discussion, however, have hitherto been scattered in numerous
technical notes and papers, often without adequate illustration, and
it has been difficult to realize the nature of the evidence. We are
now indebted to the American Museum of Natural History for an
exhaustive summary of the known Oligocene, Miocene, and ‘Pliocene
species, with exact copies of all the. original published figures of the

Reviews—Cretaceows Dinosaur Gorgosaurus. 519

fossils and with drawings of all the described specimens which have
not hitherto been figured. It is a most valuable work of reference
and indispensable for further progress. It is now possible to
understand how fragmentary is our knowledge of the various genera
- and species, and how much scope there is for differences of opinion
on all points except generalities. The broad outlines of equine
evolution are clearer than ever, and Professor Osborn has had
prepared new series of beautiful drawings to illustrate the changes
in the upper and lower molar teeth and in the feet. The excellent
manner in which the stratigraphical position of the various fossils is
determined is also fundamentally important. We are only inclined
to ask for more, and would add to our congratulations our best
wishes for the speedy accomplishment of Professor Osborn’s promised
Monograph of the Equide.

V.—Tue Crerackous THEroropous Dinosaur Goreosaurus. By
Lawrence L. Lampe. Canada Dept. of Mines, Memoir 100,
Geological Series, Ottawa, 1917.

Ge this excellently illustrated memoir the author gives a full
) account of a nearly complete skeleton of a large carnivorous
Dinosaur, Gorgosaurus libratus, found in the Belly River (Cretaceous)
beds of Alberta, Canada. This reptile is, in most respects, very
similar to Tyrannosaurus, but is said to differ from it in several
important particulars, e.g. in the structure of some of the teeth, the
proportions of the limbs, and the great development of the plastron
of ventral ribs. The fore-limb is curiously small, less than one-
fourth the length of the hind-limb. It possesses only two complete
digits (1 and 2), with powerful claws, and a vestige of the third
metacarpal; the radius and ulna are very short. The hind-limb is
remarkable for the great elongation of the foot, which, though much
larger, is very similar to that of Ornithomimus. It possesses three
complete digits (2, 3, 4) and the distal portion of the first, all claw-
bearing. The fifth is represented by a vestige of the metatarsal
only. The ventral buckler is very well developed, and consists of
about nineteen transverse rows of ventral ribs, two pairs in each
row. In the first and last the median pieces are fused, but in the
others they remain distinct but overlap, and are firmly attached to
one another, there being no median more or less V-shaped element
such as usually occurs in reptiles with such a plastron. The author
discusses the probable appearance and habits of this reptile, giving
several restorations of it in what he believes to be characteristic
attitudes. He considers that, although its mode of progression was
bipedal, in a semi-erect position, and well raised from the ground,
that when at rest the animal squatted, supported on the expanded
ends of the pubes, or lay extended on its ventral surface. The
absence of wear on the teeth suggests that the food was soft and
obtainable without much effort, probably consisting mainly of the
flesh of carcases of other reptiles such as the large Trachodont
Dinosaurs.

Co Wie AN:

520 Reviews—Fossil Insects from Commentry.

VI.—Fossiz Insects 1n CoaL-MEASURES.

Two Insecrs rrom Commantry.—R. J. Tillyard (Proc. Linn. Soe.
N.S. Wales, xlii, pp. 123-1384, March, 1918) discusses two fossils
recently described by H. Bolton (Manchester Memoirs, May, 1917).
He suggests that Megagnatha odonatiformis Bolton, is an ancient
representative of the Order Embioptera, and erects for it a new
family, Megagnathide, differing in greater size and more complex
venation, as well as, probably, in the shorter comparative distance
between the bases of the fore- and hind-wings. Sycopteron
symmetricum Bolton, ‘‘is very likely an archaic type of the Order
Psocoptera, related to Amphientomum of the Oligocene, but con-
siderably Jess specialised’ in its venation.

VII.—Rocxk-portne Oreanisms as AcrNnrs In Coasr Erosion. By
Professor T. J. Jenu. Scottish Geographical Magazine, vol. xxxiv,
pp. 11, with 8 figures, January, 1918.

i this paper the author lays stress on the importance of the part
played by rock-boring organisms in submarine erosion, and more
particularly in the lowering of the foreshore, with the consequent
further exposure of the cliffs to the wearing action of the waves.
He shows how this process is carried on to a very great extent near
Cromer and Brighton, where the chalk forms the sea bottom and
foreshore, and also at St. Andrews, where the rocks are sandstone,
shale, and limestone. The rocks are perforated by the organisms,
with the result that they are converted into a honeycomb-like
network, which is easily broken down by mechanical agencies, at first
to an irregular surface, which is soon planed down to an even
platform at the new lower level. This destruction is not continuous,
as it can only take place where the rock is free from loose overlying
sediment, but in the absence of such sediment it proceeds in very
many places, and at an average rate of about 1 inch per annum.

The work is carried out by a great variety of forms, including
annelids, sponges, molluscs, and echinoderms; these creatures mostly
preter soft or calcareous rocks, but some, more especially Pholas,
bore into any kind of rock, including sandstone, mica-schist, and
gneiss. ‘’he means by which this animal bores the rocks are some-
what obscure and many different suggestions have been put forward.
These are summarized as follows :—

1. That the perforations are made by rotations of the shell-vaives,
after the manner of augers.

2. That the holes are made by rasping, effected by siliceous
particles in the foot, or mantle, or both.

3. That the excavations are due to ciliary currents, aided by
rasping.

4. That the boring is carried out by the foot exerting suction.

5. That the rasping is brought about by the friction of gritty
particles of external derivation against the walls of the burrows.

The balance of evidence goes to show that, at any rate in the
case of the Pholadide, the action is mechanical, though acid secretion
may play some part. In experiments carried out by Miss B. Lindsay

Reviews—Dry Lakes and Lands of W. Australia. 521

at the Gatty Marine Laboratory at St. Andrews, it was shown that
the action was one of suction accompanied by scraping.

W. 4H. W.

VIII.—Tuer Dry Laxes anp Lanps or Western AUSTRALIA.

Erosion AnD RESULTING Lanp Forms In suB-ARID WeEsrEkN AUSTRALIA, -
INCLUDING THE ORIGIN aND GrowrH oF HE Dry Lakes. By
J.T. Jurson. Geogr. Journ., pp. 418-37, 2 pls., December, 1917.

On rHE Formation or ‘‘ NaruraL QUARRIES”’ IN SUB-ARID WESTERN
Ausrramia. By J.T. Jurson. Proc. Roy. Soc. Victoria (n.s.), xxx,
pp. 159-64, pls. xxviii, xxix, March, 1918.

THe Iyrivence oF Satrs In Rock WEATHERING IN SUB-ARID WESTERN
Austria. Tom. cit., pp. 165-72, pl. xxx, March, 1918.

fJ\HE dry lakes of the Salt Lake Division, north of Coolgardie and

Kalgoorlie, have been ascribed by some authors, e.g. C. G. Gibson
and J. W. Gregory, to river-systems of Tertiary, probably Miocene,
time. H. P. Woodward believed them to be wind-planed flats.
Mr. Jutson, while admitting the possibility of Miocene rivers, does
not believe that there can be any direct connection between them
and the present lake system. Given an undulating surface, such as
the present contour of the country suggests, then, in his opinion, the
existing agents seem competent to produce all the existing
phenomena, including valleys, plains, and lakes. The lakes appear
to have been formed by the processes of advancing sands, formation
of sand-bars, recession of lake-shore cliffs, and planing and hollowing
out of rock floors. ‘These processes have resulted in the formation,
dismemberment, migration, growth, capture, and union of lakes.
Many factors are responsible for the results obtained, amongst
which the wind is regarded as playing a prominent part.

The ‘‘ Natural Quarries”’ are circular, rectangular, and triangular
excavations, resembling artificial quarries, in the hillsides of various
rocks, Mr. Jutson believes that they are due to the undermining
action of rain under special conditions, which he describes.

While the action.of wind and the variations of temperature are
important agents in producing the configuration of the sub-arid
region, as they are in other deserts, something must also be assigned
to the crystallization of salts contained in the rocks in solution and
brought to the surface by capillary attraction, when the water then
evaporates. By the expansion due to crystallization flakes or grains
may be forced off or a soft rock may crumble. To such a process
Mr. Jutson restricts the term ‘‘exsudation’’. It is chiefly observed
at the base of cliffs at the edge of a dry lake. It undermines
the cliffs and the debris are carried away by wind, so that the
billiard-table floor is produced. It is curious that no pronounced
efflorescences have been noticed in these situations, though they

seem to occur on rocks that are more exposed to the sun.
Ws Av B:

522 Reviews—Zine Ores.
1X.—Imeerrat Instrrurr Monocrarus: Zinc Ores. pp. 64. Published
by the Imperial Institute, 1917. Price 2s.

Neos monograph is the first of a series now in preparation, under

the auspices of the Mineral Resources Committee of the
Imperial Institute. Its object is to give a general account of the
world’s production and resources of zinc ores, with special reference
- to the British Empire. The compilation is chiefly due to Messrs. S. J.
Johnstone and ‘I’. Crook, who have carried out their work very
thoroughly; all available sources of information have been effectively
sifted and the results condensed into a handy form. The memoir
contains sections on zinc minerals, the world’s production of zinc
ores, the ore deposits of the British Empire and of foreign countries,
the valuation, concentration, smelting, and price of the ores,
commercial spelter, and on the properties and uses of the metal.
The treatment adopted is partly geological and partly statistical,
together with references to the methods of mining and degree of
development of the individual deposits. The descriptions of the
actual manner of occurrence of the ores are often somewhat slight,
but thisis probably not the fault of the authors, since such information
is usually very difficult to obtain from the scattered literature of
mining geology. Furthermore, at the present time many new
developments are taking place in this and other branches of mining
as to which details are not yet available. However, the difficulties
inherent in a work of this sort have been successfully surmounted, and
the Committee are to be congratulated on having made an excellent
beginning of a series which cannot fail to be of great permanent value
to the mineral industries of the Empire.

X.—Tue Limestonres or SourH AFRICA.

HE Geological Survey of South Africa has published a memoir
on the Limestone Resources of the Union, by W. Wybergh
(Pretoria, 1918), containing a very full account of the known
occurrences of limestone of various grades in the Transvaal and
portions of Bechuanaland and Zululand. The total production of
lime for the year 1916 is given as 78,222 short tons, and the demand
is likely to increase in the near future. In the district under review
the most widespread calcareous rock is dolomite, which occurs in
enormous quantities both in the crystalline rocks of earliest date
and in the Potchefstroom System. Both of these types, however,
contain too much magnesia for many purposes, so that the most
valuable deposits from the economic point of view are the surface
limestones so common in many parts of the Union.

The memoir also contains a special chapter by Dr. A. L. du Toit
on the crystalline limestones or marbles of Port Shepstone and -
Hermansburg, Natal. Detailed mapping has shown that the marble
of Port Shepstone is a bent and twisted mass, enveloped and
penetrated by sheets of igneous material; the limestone must have
a thickness of several thousand feet, and the metamorphism produced
in it is of extraordinary theoretical interest. A detailed description
is promised in a future publication.

ee ee

Reviews—The Hurunur Valley. 523

XI.—Srrucrurat anp Gractat Frarures oF THE Hurunur VALLEY.
By R. Sperent, M.Sc., F.G.S. Trans. New Zealand Institute,
vol. 1, pp. 93-105, 1917. :

f{\HE chief interest of this valley is that it is an excellent example

of a process of river development which is described by the
author, following Dr. Cotton, as ‘‘ante-consequent”. The geological
history of the district is as follows: On an incompletely levelled
surface of greywacke a series of Tertiary beds consisting of limestones,
marls, greensands, and conglomerates was laid down, the uppermost
of these being of Pliocene age. As these beds rose from the sea
a system of consequent drainage was established on the surface of
the land with sub-parallel streams running eastwards. When these
rivers had established their courses folding and faulting took place
along lines inclined at about 45° to the course of the streams. ‘hese
movements produced a number of parallel intermontane basins filled
with Tertiary rocks and separated by ridges of greywacke, and along
these basins most of the tributaries flow to the main stream. ‘These
movements were of quite recent date and must have been very slow,
since though in the upper parts of its course the direction of the
stream is somewhat affected by them, in its lower reaches the river
was able to preserve the direction of its channel and cuts straight
through the greywacke ridges separating the basins along what must
have been its original line. In this respect the Hurunui River is
exceptional among the rivers of this region, since the courses of
similar streams to the north have been much disturbed by these
movements.

In the succeeding Pleistocene glaciation the ice probably did not
penetrate to the lower portions of the valley, but the upper parts
were filled with glaciers and show evidence of strong ice action. On
the northern branch of the river, the ice, after arriving at the head
of a large lake called Lake Sumner, split into several distributaries
which passed over cols between the hills standing inside a right
angle formed by a bend in the course of the river. These cols have
consequently been lowered, partly by the cutting back of the corries
at the heads of the valleys running down from them and partly by
the ice streams flowing over them from above. Lower down at the
end of the eastern limb of the right angle these distributaries united
with the main glacier and were also joined by that from the south
branch of the river.

W.4H. W.

XIJ.—Tuer Grotocy or Banxs Penrysura. By R. Sprrent, M.Sc.,
F.G.S. Trans. New Zealand Institute, vol. xhx, pp. 365-92,
with 3 plates and 4 figures, 1916.

ANKS Peninsula, which is situated nearly in the middle of the
east coast of the South Island of New Zealand, is a mass of
voleanic rocks about 25 miles long by 18 wide, projecting almost at
right angles from the coast. The surface is very hilly and rises to
a height of between 2,700 and 3,000 feet in several peaks. It is
bounded on the north, east, and south-east by the sea, on the west

524 Reviews—The Geology of Banks Peninsula.

by low-lying marshy plains, and on the south-west by a large
shallow lake, Lake Ellesmere, which is separated from the sea by a
long narrow shingle spit. The volcanic rocks were to a great extent
poured out from two vents which are now represented by the two
large calderas of Lyttelton Harbour in the western. and Akaroa
Harbour in the eastern portion of the peninsula. , hese calderas
have been converted into fjord-like inlets by erosion, and open on to
the north-west and south-east coasts respectively. Part of the
drainage of the region flows into the harbours, but most of it is
roughly radial, and the consequent streams flowing outwards from
the lips of the calderas enter the sea in a series of openings of the
ria type which indicate recent submergence.

The geological foundations of the peninsula are a series of slates
and greywackes which probably ‘belong to the Trias—Jura Maitai
system. On these rest the volcanics, which belong to four distinct
periods of activity. The rocks belonging to the first phase are
rhyolitic, and rest on the upturned edges of the older rocks; they
are nearly all lavas, with only one irregularly distributed fragmentary
deposit at the base. The vent was situated near Lyttelton, and, by
analogy with similar rocks elsewhere,.the eruptions probably took
place in Cretaceous times. The second phase was marked by the
building up of the two great volcanoes whose sites are occupied by
the calderas of Lyttelton and Akaroa Harbours. Both these
mountains were made up of basaltic material and were composite
cones of alternating lavas and fragmental deposits; they were both
probably at least 10,000 feet in height. The lavas vary from fine-
grained basalts to rocks largely made up of felspar phenocrysts.
This voleanic phase was followed by a dyke phase. These dykes
are mostly trachyte, but some are andesite and basalt; they have
a roughly radial arrangement which allows the position of the vents
to be determined with tolerable certainty. The strike is not,
however, constantly radial, and mutual intersections of the dykes
are numerous. In the Akaroa area there is a large mass of coarse-
grained hornblende syenite ; this may be associated with the dykes,
but it is cut by some of them and is probably part of the original
land mass.

Before the next volcanic phase the calderas had attained a form
not far removed from that which they have at present; during this
phase basaltic lavas were poured out from a vent in the neighbour-
hood of Mt. Herbert, about half-way between Lyttelton and
Akaroa, the date of the eruptions being probably Pliocene.

The last volcanic phase was that which produced the basaltic
flows and ashes of Quail Island in Lyttelton Harbour. The island
is in the middle of the caldera and probably marks a final outburst of
this vent.

Some time after this last event the land was depressed to an extent
of at least 700 feet, as may be shown by the occurrence of peat beds
at this depth in boreholes in the plains to the west, and this move-
ment has only lately given place to one of slight emergence.

The author holds that the calderas are chiefly the product of
subaerial erosion, partly river and partly wave action. There must

Reports & Proceedings—Edinburgh Geological Society. 525

have been an explosion to produce a hole of sufficient size for the
rivers to work in, as the original crater would never have been large
enough; but no great part of the excavation can have been done in
this way, since, though the calderas were formed before the out-
pouring of the lavas of the third volcanic phase, there is no
fragmental deposit at their base, such as must have been produced
by so great anexplosion. The forms of the inner slopes are also more
in accordance with the theory of river erosion. After the initial
explosions, then, the cone was breached, either by a lava-flow or by
the cutting back of a stream, and finally carved out to its present
shupe by subaerial agencies.

XIII.—Tue Aprronpack INTRUSIVES.
THe Prosiem oF tHE AnortHosites. By N. L. Bowen. Journal of
Geology, vol. xxv, pp. 209-43, 1917.
SrrucTuRE or tHe Anorrnosire Bopy in tHE Apironpacks. By
H. P. Cusuine. Ibid., pp. 501-9.
Aprronpack Intrusives. By N. L. Bowen. Ibid., pp. 509-12.
Aprronpack Intrustves. By H. P. Cusine. Ibid., pp. 512-14.

N the first paper Dr. Bowen discusses the origin of anorthosites in
general, with special reference to those of the Adirondacks and
of Morin, Canada. His general conclusion is that anorthosites are
produced by the straining off of femic constituents by gravity from
a)gabbroid magma; at a later stage of the cooling the crystals of
more basic plagioclase sink in their turn, forming the anorthosite
mass, while the acid residue forms a syenite. The Adirondack
complex is thus interpreted as a sheet-like mass with syenite above
and anorthosite below.

In the second paper Professor Cushing expresses his general
agreement with Dr. Bowen’s views as to the origin of the anorthosites,
but dissents from his interpretation of the field relations ; he concludes
that the syenite does not form an overlying sheet, but is mainly
intrusive into the anorthosite, and the border of gabbro is to be
regarded as a chilled margin. The two remaining papers continue
the discussion of the points raised in the previous ones.

levy Joba es,

RP ORES (AINED PROC HazD» PNG S-

I.—Epineurew GrotocicaL Socrery.

March 20.—Dr. M‘Lintock, Vice-President, in the Chair. (Issued
October 11, 1918.)

1. ‘‘ Limits of the Valley Glaciation in the Basin of the Dee.”
By Dr. Bremner.

Ig late Glacial times an ice-stream descended the upper Dee
valley and, reinforced by affluents from Glenmuick and Glengairn,
formed a great valley glacier that extended to a point fully a mile
east of Dinnet railway station. The limits of its extension have

526 Reports & Proceedings—Liverpool Geological Society.

been determined by mapping the lateral and terminal moraines,
marginal channels, and overwash deposits.

That the period of the valley glaciers formed a distinct phase in —
the history of the Ice Age is suggested by the occurrence between
Cambus o’ May and Dinnet of two boulder-clays: in two sections
one can be seen superposed upon the other. The upper, the moraine
profonde of the valley glacier, differsin composition and resistance to
denudation from the lower, the product of the ice-sheet.

The whole or a great part of Glentanner, also, seems to have been
oe by a valley glacier.

“Occurrences of Old Red Sandstone in and near Aberdeen.”’
nC De Bremner.

Old Red Sandstone is known to occur at seven different places
over a considerable area within the city boundaries. In a bore at
Sandilands Chemical Works the rock was encountered about 96 feet
below O.D., and at 625 feet below O.D. it had not been bottomed.
A Lemon Street bore entered it at 60 to 65 feet below O.D. At
‘Woolmanhill it was encountered at sea-level, and found to have
a total thickness of 189 feet; the bore was Cae down 9 feet into
the underlying metamorphic rock.

A small ‘outerop occurs in the banks of the Millden Burn, 6 miles
north of Aberdeen.

All the rock proved is of Middle Old Red type.

3. ‘‘ Notes on the Lochend Sill.””? By Robert Allan, B.Sc.

Some particular features in the petrology of the Essexite intrusion,
previously described in the G.S. Memoir on the Rocks of the
Neighbourhood of Edinburgh, were pointed out and illustrated by
means of lantern views. ‘The great variation which occurs throughout
the sill, the characteristic feature of which is the presence of a sdda-
rich felspar, was also indicated. Particular slides were shown in
which the relationship between the ilmenite, biotite, and chlorite
present in the rock was brought out. Both at Hawkhill and
Lochend portions of the intrusion have a spotted appearance, and
these spots in many instances were found to consist mainly of
analcite, and seemed to be of the nature of ocelli, or local
segregations of the residual magma late in crystallizing out.

I1.—Lrverpoot Gxrorocican Socrery.

October 8, 1918.—J. C. M. Given, M.D., M.R.C.P., F.G.S., President,
in the Chair.

At the annual meeting of this Society, which now enters upon its
sixtieth session, the President read an address upon ‘‘ The Geological
Position of Primates’’, in which he gave an account of recent
research and discoveries bearing upon the origin and antiquity of
man. The writings of Rutot and others on the so-called ‘“ Holiths’’,
which they claim to be of human manufacture, would take back
man’s origin to at least Miocene times, and had led to wild specula-
tions on the subject, so that it seemed profitable to consider the
question, not from the standpoint of the earliest appearance of man,

Obituary—Bishop Mitchinson. 527

but of his predecessors in mammalian evolution, for if man belongs,
as he certainly does, to the highest order of the mammalia, namely,
the Primates, it must be a waste of time to try to prove him to be
earlier than these his manifest ancestors. The classification of the
mammalia was first reviewed, and the modern distribution of the
higher mammals over the face of the earth examined, as a preliminary
to describing their fossil ancestors and_ geological relations.
A description followed of the zoogeographical areas of the earth’s
surface, and their characteristic faunas, and it was made clear that
the Primates first appeared as very primitive lemurs in the Upper
Eocene, as in the Wasatch formation of Wyoming, U.S.A., and in
Europe in the Phosphorites of the Paris Basin, as also in Switzerland,
and in Hampshire in this country, but that not until the Oligocene
of the Egyptian Fayoum is reached are any traces of the real ape
tribe to be found. In the Miocene they can be discerned a little
more plainly, but only in the Pliocene do the larger man-like apes
first manifest themselves. Therefore, in spite of the ‘‘ Koliths”’, it
would seem, a priort, to be very unlikely that Homo sapiens, or his
immediate lineal ancestors in the Anthropoidea, will be found earlier
than this.

(DIS CBEN OL NASg NaS

LIEUT. GRAHAM JOHNS,

Scots GuaRpDs.

Lievr. Granam Jouns, Scots Guards, son of Mr. and Mrs. Cosmo
Johns, of Sheffield, was killed in action on September 27. He
matriculated at Caius College, Cambridge, but did not go into
residence. He was severely wounded at Ypres, July, 1917, and
returned to the Front in March this year.

THE RIGHT REV. BISHOP JOHN MITCHINSON,
DO i. DID ayGs

BORN SEPTEMBER 23, 1833. DIED SEPTEMBER 25, 1918.

We regret to record the death of Bishop Mitchinson, Master of
Pembroke College, Oxford, who was a lifelong student of geology
and a devoted friend of geologists. From 1859 until 1873 he was
Head Master of the King’s School, Canterbury ; from 1873 until 1881
he was Bishop of Barbados; from 1881 until 1899 he held the
benefice of Sibstone, Leicestershire, and acted as deputy in much
episcopal work; and in 1899 he was elected Master of Pembroke.
While in Barbados he spent part of his leisure in making a collection
of fossils, which he gave to the British Museum in 1892. While at
home he made numerous excursions in search of fossils, and
eventually brought together a good representative series, which he
carefully studied and arranged in cabinets. After reserving for
Oxford a few specimens, among which was the type of Olenus
Mitchinsoni from the Shineton Shales, described by Dr. H. H. Thomas

\

528 Obituary—Henry Shaler Williams.

in 1900, he gave this valuable collection to University College,
London. For several years Bishop Mitchinson was a valued member
of council of the Geological and Paleontographical Societies, and he
was never happier than when entertaining parties of his colleagues
in the Master’s Lodge at Pembroke. The memory of these parties
will always be cherished by those who shared his hospitality, for he
was the most genial of hosts, the most lovable of friends, and full of
lively interests.

AS: We

HENRY SHALER WILLIAMS,
Pu.D., F.G.8.

Born MARCH 6, 1847. Diep AUGUST, 1918.
AMERICAN geology loses a distinguished representative by the death —
of Professor H. 8. Williams, of Cornell University. He graduated
as Ph.D. at Yale in 1868, and inclined at first towards biologieal
studies, which stood him in good stead when he specialized later in
paleontology. In 1879 he was appointed Assistant Professor of
Geology and Paleontology in Cornell University, and in 1886 he
became full Professor. In 1892 he succeeded Dana as Silliman —
Professor at Yale, and in 1902 he returned to Cornell. In 1912 he
retired with a pension under the Carnegie Foundation. Professor
Williams devoted himself especially to the study of the Devonian
invertebrate faunas and the correlation of the Devonian formations
of North America. His results were published chiefly in the
Bulletins of the Geological Survey of the United States. He was
a pioneer in the modern methods of paleontological research, and
his volume on Geological Biology (1894) is an admirable statement of
principles.

MISCHLILUIANHOUVUS.

ES
Tue Cuvier Prize.

The French Academy of Sciences has awarded the Cuvier Prize for
1918 to Dr. Arthur Smith Woodward, F.R.S., for his researches in
Vertebrate Paleontology. This is a triennial prize and was first
awarded in 1851 to Louis Agassiz. It has already reached Great
Britain three times, having been given to Sir Richard Owen in 1856,
to Sir Roderick Murchison in 1868, and to Sir John Murray in 1894.

H. C. Beastry Gronoagicat Connection.

The Liverpool Free Public Museums have recently acquired the
valuable and unique collection of Triassic fossils, rocks, and minerals
formed by Mr. H. C. Beasley, which has been purchased from him by
Mr. C. Sydney Jones, M.A,, J.P., and presented to the City. The
collection is chiefly a local one, and is especially rich in fine specimens
of cheirotheroid, rhynchosauroid, and chelonoid footprints from the
Lower Keuper of‘the well-known Storeton Quarries, and from
Runcorn Hill.

MEMOIR of JOHN MICHELL

M.A., B.D., F.R.S., Fellow of Queens’ College, Cambridge, 1749,
Woodwardian Professor of Geology in the University, 1762

BY
SIR ARCHIBALD CEIKIE, 0.M., K.C.B., D.C.L., D.Sc., F.R.S.
Crown 8vo. 2s 6d net.

‘*John Michell applied his high intellectual powers to geological questions,
and, working without the key subsequently provided in the discovery of
fossiliferous deposits, forecasted many of the conclusions established by later
researches. In physics and astronomy he was the pioneer in devising the
torsion balance, which yielded such important results in the hands of Coulomb
and Cavendish. Though he enjoyed the esteem and respect of the most
eminent men of science in his lifetime, his name, mainly because others
entered into his labours and carried them to their full fruition, fell later into
unmerited obscurity. The thanks of students of the scientific history of our
country are due to our veteran geologist for the compilation of this valuable
and interesting memoir.’’—The Glasgow Herald

Cambridge University Press

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METHODS IN PRACTICAL PETROLOGY

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Cambridge: W. HEFFER & SONS, Ltd.

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PALAONTOGRAPHICAL SOCIETY,‘1916.— Vol. LXX. £1 5s. net.

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GAG) SINS Gy SB IND re

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Notes on Yunnan Cystidea. Part II.
By Dr. C. S. Du Riche Preller... 551

I. OrtGINaAL ARTICLES. Page | REVIEWS (continued). Page
Coal in Spitsbergen. By W. H. | The Geology of Vancouver. By
| WILCOCKSON, M.A., F.G.S....... 529 ee TENT 213) vsiawas lay eee aes 550
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By F. A. BaruER, D.Se., F.R.S

(With Text-fieures.) ...... 532 | Tertiary Beds, Castle Hill. By
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(Paqityaed bs deepsea De eRe E aeons 540 | Distribution of Igneous Rocks, New
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New Bennettitean Cones from Cre- Ill. REPORTS AND PROCEEDINGS.

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NEW SERIES. DECADE VI. VOL. Ve

No. XII.— DECEMBER, 1918.

ORIGINAL ARTICLIEHS.-

I.—Coat In SPprrsBERGEN.
By W.H. Witcockson, M.A., F.G.S.

LTHOUGH the existence of coal in Spitsbergen has been known

for a very long time, it is only of recent years that development

has been undertaken on any considerable scale. As early as 1610

explorers brought back with them small amounts of coal to burn on

the voyage home, and in 1614 the islands were formally claimed for

James I by the Muscovy Company. The coal was also described

from the scientific point of view by Nathorst and others at various

dates, but no attempt was made to work it till about 1904, when the

Arctic Coal Company, an American concern, opened a mine at
Advent Bay.

The Spitsbergen Avalide | is made up of a number of islands of
a total area about equal to that of Ireland. The greater part of the
land is divided between West Spitsbergen, which is by far the
largest, and North-East Spitsbergen: the relative position of these
two land-masses is imphed by their names. In addition to these
there are Prince Charles Foreland off the west coast of West
Spitsbergen, and Barents Island and Edge Island lying south of
North-East Spitsbergen. Structurally, the islands are part of the
old North Atlantic continent, and are broken up by subsidences and
bounded by fractures, which were accompanied by eruptions.

Along the west coast of West Spitsbergen there is a narrow belt
of highly folded and crumpled rocks, which has been affected by
several successive mountain-building movements, continuing down
to Tertiary times; further east this folding, faulting and thrusting
dies out, and the remainder of the island is made up of a high plateau
with regular stratigraphy and gentle dips, deeply trenched by the
inlets of Ice Fjord and Bell and Lowe Sounds, which extend far
into the interior. In the western zone the older and newer strata
are much folded together, and here the oldest rocks found in the
island, the Hekla Hook formation, are exposed. These are lime-
stones of Ordovician age, followed by Silurian quartzites, dolomites,
and sandstones. ‘They are succeeded by Devonian beds, which are
the oldest rocks seen in the interior, and are composed of a mass of
red strata very like the British Devonian. On these Carboniferous
limestones and cherts rest with a strong unconformity, and are in
turn followed by a belt of sandstones and shales referred to the
Permian. Above these lie the Triassic atpate, chiefly shales or clays

DECADE VI.—VOL. V.—NO. XII. 34

530 W. H. Wilcockson—Ooal in Spitsbergen.

with thin limestones, sandstones, and phosphate beds, often rich in
well-preserved marine fossils. After these follow Jurassic and
Tertiary strata, which are very thick and in apparent conformity :
these build up the high plateau of Ice Fjord. They are chiefly
composed of sandstones and shales of marine origin, with occasional
bands containing marine fossils. They also yield abundant plant
remains and both contain coal, in consequence of which they are
the most important strata in the islands from the economic point
of view.

The age of the coals is somewhat undecided: in 1897 Nathorst
determined the age of some of the seams to be Upper Jurassic, and
he considers that those on the west side of Advent Bay are Tertiary,
while the American writers Stevenson and Morris believe that they
are all Jurassic. Bituminous coal, cannel coal, and anthracite are
all found in the islands. Generally speaking, the carbon percentage
is very variable, especially between the top and bottom of the
individual seams, and the ash content is high. The coals, however,
are good for steam-raising, and especially so for use in closed stoves,
which makes them particularly well suited for export to Scandinavia
and Russia. Four analyses from the Green Harbour— Advent Bay
district gave the following results :—

Per cent
Coke production . 3 ; : . 54-60
Gaseous content . 5 ‘ : 5 87-44
Ash é : ; : j 3 . 3:8-5-6
Water at air drying : : ; 3 3-4
Water at 100°C. . ; : 1-5

The heating capacity of these samples was 12,000 British thermal
units.

The coal is mined both in the folded zone and in the plateau
region. In the latter the beds have a gentle dip, and the seams can
be seen cropping out on the hillsides generally between 450 and
600 feet above the sea, though they are known to exist up to
1,300 feet, but at this height they are unworkable, partly owing
to the cold and partly to the steepness of the slopes. For the mining
of these flat or gently dipping seams shafts are unnecessary, since
all the seams can be worked by adits driven in from their outcrops.
No fire-damp has been met with and the mines can be worked all
the year round in spite of the temperature, which is always as low
as —4°C.in the drives, so that the coal faces are covered with ice or
hoarfrost. The steepness of the slopes renders transport somewhat
difficult, and at one mine on Advent Bay the coal is brought down to
the wharf by an aerial ropeway. On the other side of Advent Bay
a tramway is in operation and a railway is projected from the
Swedish concessions in Buntzow’s Land at the head of Ice Fjord to
an ice-free harbour on Bell Sound.

The coal-seams average about 3 feet in thickness, though some
have been reported up to 12 feet thick: they are often pure coal
throughout, though at some places, such as Green Harbour and
Advent Bay, they are known to split. At the former locality there
are two coal-seams, the upper one of which splits as follows :—

W. H. Wilcockson—Coal in Spitsbergen. 5381

ft.
Pure coal : - A 5 3 A 3
1
i

ee

DOO

Coal slate
Pure coal

while at Advent Bay there are two intermediate beds, aggregating
2 feet, separating three coal-seams which together have a thickness
of 5 feet.

The coal areas in West Spitsbergen are nearly all included in an
irregular quadrilateral, 100 miles from east to west by 130 miles
from north to south, the boundary extending from the Brogger
Peninsula on the west coast to Wiche Bay on the east, thence south
to Whales Bay and across to the west coast again at Dunder Bay.
In addition, coal claims have been taken up at Hope Bay and all
over Prince Charles Foreland and Barents Island. The coal districts
on the main land are all situated either near open sea or near
navigable waters in Ice Fjord and Bell and Lowe Sounds, where the
coal can be loaded directly on to the ship. They are owned by
several different nationalities in the following proportions :—

Square miles.

British . 3 Z i ; : 3,574
Norwegian : : ‘ : j 770
Swedish . ‘ F ; 5 % 448
Russian . 3 g ; : : 80
German . ij ! : A ‘ 23

The British claims are situated on Prince Charles Foreland and at
Kings Bay and Brogger Peninsula, around Bell and Lowe Sounds,
in the district west of Wiche Bay, at Hope Bay, and on Barents
Island. The Norwegian and Russian claims are on the south shore
of Ice Fjord, the Swedish in Buntzow’s Land at the head of Ice
Fjord and at the head of Lowe Sound, and the German near
Kings Bay.

The chief British company operating in the islands is the Northern
Exploration Company, which owns 2,000 square miles of claims and
which instigated the large expedition organized by Sir Ernest
Shackleton, which has recently returned to this country. Another
British company is the Scottish Spitsbergen Syndicate, of Edinburgh,
which puts forward claims to the Buntzow’s Land district, at present
oceupied by the Swedish Spitsbergen Company. ‘There are also
two large Norwegian companies, one of which recently acquired the
American Arctic Coal Company’s mine at Advent Bay.

The. last-named company, which began work in 1904, had an
annual output of about 50,000 tons, and this together with some
coal mined by a British company at Green Harbour, also on the
south side of Ice Fjord, was the whole output of the islands till
the outbreak of war in 1914: at that time development on a much
larger scale was planned, but was unavoidably postponed, so that
the total output for 1917 was only 100,000 tons, all of which was
exported to Norway and Sweden.

The coal reserves of the islands have recently been estimated at
8,000,000,000 tons, a figure which is probably considerably below
the mark, if the reports of the Swedish company may be trusted.

5382 Dr. F. A. Bather—Notes on Yunnan Cystrdea.

This company alone estimates whee the reserves in its holdings are
as follows :—

: Tons.
Braganza District : : : 340,000,000
Pyramide Mountain . é : 380,000,000
Buntzow’s Land . ; ; . 38,000,000,000

The Swedish holdings are small compared with the British, and,
unless the former are abnormally rich, it must be assumed that the
available reserves are many times as great as the figures quoted
above, and it seems probable that Spitsbergen will ultimately be able
to supply all the coal required by Scandinavia and North Russia.
For this trade the British-owned fields are most advantageously
situated; lying as they do chiefly north and south of Bell and Lowe
Sounds they are nearer and more accessible for ships plying to these
countries, and they can obtain and hold a dominant position if the
requisite facilities are given.

In addition to coal the islands possess other mineral resources,
notably marble, which is said to be of good quality; the British-
owned territories are highly mineralized and contain deposits of
hematite, magnetite, copper ores, iron and copper pyrites,
molybdenite, galena, zinc-blende, and other minerals, the develop-
ment of which has been held back by the war. Very optimistic
reports have lately been issued as to the resources of iron-ore, which
are said to be of nearly as high quality as the Swedish ores, and to
be of enormous extent: these statements, however, seem to need
confirmation.

The political situation in Spitsbergen is at present in rather an
indefinite position; attracted by the success of the American and
British enterprises, Norwegian, Swedish, and Russian prospectors
landed and began to ‘‘ peg out”’ claims, and in 1912 the archipelago
was visited by Prince Henry of Prussia and the late Count
Zeppelin. A wireless station, which has since been dismantled,
was erected by the Germans, who also ‘‘ pegged out’”’ coal claims.
Spitsbergen, however, is one of the few remaining countries not
under the government of any great Power, and may be classed as
a No Man’s Land. In consequence of this there was no control of
the claims, and aconsiderable amount of overlapping and ‘‘jumping”’
occurred. To settle this question an International Congress was
held at Stockholm in 1912, at which delegates from Sweden,
Norway, and Russia were present. This Congress, however, accom-
plished nothing, and it now seems probable that the islands will
become internationalized, since their British ownership long since
fell into abeyance.

II.—Nores on Yunnan Cystipra. II. Tue Sprcres or Sxvocystis.
By F. A. BATHER, D.Sc., F.R.S.
(Published by permission of the Trustees of the British Museum.)
Sinocystis locsyt Reed. (Text-figs. 5, 8, 9, 10, 11.)
Specimens I, 1-8 were studied. Probably those measured under
Dr. Reed’s heads I and II refer to 1 and 3 respectively. Specimen 1
is hereby selected as Holotype.

Dr. F. A. Bather—Notes on Yunnan Cystidea. 5388

The following are measurements in millimetres :—

Specimen . 1 2 3 4 5 6 7
Height . 74:7 71-0 79-0 60-0 17-5

Greatest 44-5 40°/58-0 160°} 56-6 80°/45-3 25°)18-2 5°

diameters 43-8 160°|43-0 60°) 53-7 0°|35-8 130°] 16-4 100°

Diameters 11:0 13-9 ca. 8-5 15-0 7-3 10-7 an 9-0
at base 9-0 10-4 10-3 6-3 8-1 °8-5

Peristome 95° 106° 80° 95° 105°} — —
plane

Specimen 8 consists of two rather large but incomplete individuals in matrix.

In order to indicate the planes of compression, the oro-anal plane
is marked 0°-180°, 0° being anterior, or North in the usual
orientation of drawings of the adoral face. The angle formed by
each plane of compression with the oro-anal plane is reckoned in
degrees on the right-hand side. The direction of the extended
peristome is denoted in the same way. From this it will be seen
that the compression bears no constant relation to any morphological
plane, and is therefore due to causes acting after death. The theca
was essentially ovate-pyriform, and its true diameters may be
roughly estimated by taking the mean of the double measurements.
The theca was upright (1, 3, 5?, and 6), or bent over on its stalk (2)
so as apparently to have almost lain on the sea-floor; but since in
this case the anus would thus be facing the sea-floor, it is more
likely that the base was fixed to the side of some object.

The variation of angle between the peristome plane and the anal
plane may be regarded as due either to a shifting obliquity of the
mouth or to the migration of the anus. If checked by reference to
the hydropore, it will be found that the former is probably the truer
statement. The bearing of this decision appears when one examines
the four branches, their direction and diverse lengths. It will then
be observed that the peristome is not an oblong, parallel to the
hydropore and at right angles to the anal plane, with four equal
branches, passing one from each corner at equal angles. It is the
departures from that simple but imaginary scheme which are of real
interest, as pointing to the original plan of which the existing ones
are modifications (Text-fig. 8). The extreme of departure is provided
by I, 2, but similar features are seen, though less marked, in I, 1, 3,
and 4, First, as already shown by the table of measurements, the
peristome lies at an angle to the anal plane of 106°, or 16° in excess
of aright angle. Secondly, the hydropore slit, which is never quite
straight, but concave towards the mouth in a more or less
symmetrical curve, is neither parallel to the peristome nor
symmetrically placed in regard to it; on the contrary a line joining
the centres of hydropore and anus will, if produced, meet the
peristome at its left end, just where the branches diverge. Thirdly,
the branches do not form equal angles with the peristome. The
two branches on the left include an angle rather greater than 90°
(actually 110° in specimen 2), and the peristome plane does not
bisect this angle but les anterior to its bisection. On the right the
angle included by the branches is about 90°, and here the peristome
plane lies posterior to its bisection, and that in an even greater
degree. Fourthly, the branches are of diverse length; the left

5384 Dr. F. A, Bather—N otes on Yunnan Cystidea.

posterior is always the longest: in I, 2 it is 8mm. long; next comes
the left anterior, 5-4mm.; then the right anterior, 4:5mm.; and
lastly the right posterior, 33mm. ‘The length of the -peristome
between the forks is 7mm. The conclusion to which these facts
lead is that the four-rayed and approximately quadrangular
subvective system of Sinocystis is really a modification of the three-
rayed system, which I have previously held to be the primitive
arrangement in Pelmatozoa (1900, Treatise on Zoology, p. 11, and
elsewhere). On this view, the true or primitive oral centre lies at
the axil of the left fork; the anterior of the two branches on the
left is the true anterior ray, and it is noteworthy that, in I, 2 at any
rate, its line if produced almost coincides with the line joining
hydropore and anus; this, then, marks the true or primitive sagittal
plane, coincident, as it should be, with the M plane (Text-figs. 2, 4);

R
R a fe a _ a
) as \ J}

\% a4
ry Ay drop ore : “2
g OnOpore /

8
2 {. 4 2 periproct’ z

Fic. 8.—Sinocystis loczyi: diagrams, taken as accurately as possible from
specimens I, 1, 2, and 3, to show the varying relations of the subvective
system to the thecal openings. All are oriented with the anal plane
running N. and S., the oral pole being taken as midway between the
forks. If the oral pole were at the origin of the left-hand fork, then a line
joining it with the anal pole would pass through the hydropore, and (in
2 and 3 at any rate) would be continuous with the anterior branch of the
fork. This line would then represent the primitive sagittal plane, and the
branch would be the anterior of the primitive three rays (cf. fig. 4, antea,
also Treatise on Zoology, 1900, p. 11, fig. IX). Nat. size.

the posterior of the two left-hand branches is the primitive left
posterior; and the line of the peristome marks the primitive right
posterior branch. This last branch (one supposes) after a time bent
shghtly towards the anus, and gave off a branch, which in Srnocystis
is the right anterior. This is precisely the same change as took place
in the evolution of any normal five-rayed pelmatozoon, but there the
left posterior branch also forked in the same way, thus completing
the quintet.

The Brachiole-facets, which, owing to the biserial structure of the
eystid brachiole in general, are composed of two halves, are seen in
I, 1, 2, and 4,-but by no means clearly (Reed, pl. I, fig. 2a, left
anterior branch, is the clearest representation). In some cases there
is a suggestion of more than one facet at the end of a main branch.
(see Reed, pl. I, fig. 4, right anterior branch); if there were actually
two facets, it would imply a forking of the branch, in which there
is nothing impossible.

The relation of the adjacent thecal plates to the Subvective

Dr. F, A. Bather—Notes on Yunnan Cystidea. 585

System is not quite clear and does not seem to be constant. Each
facet appears, as Dr. Reed says, to be ‘‘situated in the centre of
a slightly swollen ordinary thecal plate’’. The hydropore seems at
first glance to be on a single plate, adjoining the peristome and
filling the posterior interradius. On the other side of the peristome,
in the opposite interradius, two plates are discernible in I, 4, and
perhaps in 2 and 3. The thecal plates adjacent to the hydropore-
plate suggest that it too is really compound, and this view is
supported by S. mansuy?, II, 9 (see Reed’s figure). It is usual for
a hydropore-slit of this shape to cross a suture. This would give
8 adoral plates, of which the right and left pairs would bear facets ;
the posterior pair would bear the hydropore, and the anterior pair
would bear nothing (Text-fig. 9). The occurrence in all species of
Sinocystis of diplopores on all these plates, right up to the facets,
grooves, ete., is noteworthy (Text-fig. 12).

10 :

DaUSDOY,
ULL, VIMY, ; SSS

12

9 11 13

Fic. 9.—Sinocystis loczyi: diagram of the eight adoral plates. The broken
- lines are restored by me; all others are traced from Mr. Brock’s
drawing (Reed, 1917, pl. i, fig. 4). x 3.

», 10.—Sinocystis loczyz: section across the peristomial ridge; the exterior
outline based on I, 4; the interior imaginary. The summit notch
is due to weathering. x #.

», 11.—Sinocystis loczyi: side-view of a part of the peristomial ridge in
I, 4, to show how the cover-plates interlock. x #.

,, 12.—Sinocystis mansuyi: section across a subyective groove as seen in
II, 7. Note pore-canals of a diplopore on the right. x #

5, 13.—Sinocystis mansuyi: the hydropore in II, 2. x circa?.

Dr. Reed says of S. loczyz ‘‘mouth narrow, straight, slit-like,
slightly raised’, It is not certain what he means by ‘‘ mouth ”’.
Apparently the sentence quoted refers, to the thread-like slit clearly
shown in pl. I, fig. 4 (cf. Text-figs. 9,10). This, however, is
not a natural opening into the thecal cavity. The peristomial
aperture is not actually visible in any of the figured specimens.
From the disposition of the cover-plates, however, supported by the
evidence of closely similar fossils from elsewhere, it may be inferred
-that the peristome in I, 1 was an oblong, measuring about 4°5mm.
by not more than 2mm. The aperture and the grooves leading from
its corners to the brachiole-facets were, as Dr. Reed says, ‘* covered
with a double row of small alternate polygonal plates set in a narrow
rebate around their edges [i.e. of mouth and branches] and forming
a roof-like ridge.” The arrangement of the cover-plates is shown,
though not very clearly, in Reed, pl. I, fig. 2a. It may be better
understood from the annexed side-view of the tegminal ridge in I, 4

536 Dr. F. A. Bather—Notes on Yunnan Cystidea.

(Text-fig. 11). Resting on the rebate is a series of squarish plates,
with their upper angles irregularly bevelled off. On the larger
shoulder of each such plate rests a triangular plate; in side view
this does not appear triangular because its apex is bent over on to
the other side (as seen in I, 2). The apices of the corresponding
triangular plates of the other side, similarly bent over, are seen
resting on the smaller shoulders of the squarish plates. There are
slight deviations from this general structure, but the essential fact
to notice is that the triangular plates cross the median line and
interlock. The appearance forcibly suggests that the cover-plates
did not open but formed a fixed tegmen. In any case a slit which,
as in I, 4, cuts across the triangular plates, cannot represent a
natural opening.

The Hydropore has been mentioned in connexion with the
orientation of the subvective system. It is always concave towards
the peristome and tends to face its left corner (the supposed primitive
oral polej. In I, 4 the slit seems to branch at its right end, but
probably there is a small root of another cystid growing across it
(omitted in Text-fig. 9).

The following are some measurements in millimetres of the
hexagonal Anal pyramid :—

Specimen . 1 2 Ber 4 5
Least distance of anal centre from
edge of peristome . 5 : 18-0 17-0 12-8 10-2 4-8
Diameter, side to side . ‘ 3-7 4-5 3°7 3-0 3-2
i angle to angle 4 4-0 5:8 4-7 3-7 3°6
Length of peristome, circa . 4-5 5:8 6-0 5:2 3-0

The approximate length of the peristome is introduced for
comparison with Dr. Reed’s statement that the anus is ‘‘ distant from
it [the ‘mouth’ | about twice its [the ‘mouth’s’]length”. According
to the fixed points selected for the above measurements, this ratio of
2:1 holds for specimens 3 and 4; the ratio for I, 1 is 4:1; for
I,2, 3:1; and for I,5, 1°6:1. Arranging the specimens in order
of size, downwards, the ratios are 2, 3, 4, 2, 1:6. he chief interest
les in the irregularity and lack of any correspondence between size
and position, which indicate that the anus did not migrate appreciably
during growth (v. supra, p. 534).

The Gonopore is subcircular with a tendency to be pentagonal, this
outline suggesting that the opening was closed by five valves, though
no other traces of them are preserved.

The following measurements in millimetres show that irregularity
also obtains in the distance of this from the anus :—

Specimen. : 1 2 3 4 5
Distance of Gonopore centre from
anal centre : : 9-2 6:0 3-7 4°3 3°7
Diameter of Gonopore lumen, circa — 1-4 1:3 6 —

The edge of the gonoporeis raised slightly in I, 3, 5, and conspicuously
in 4; in I, 2 the rim is very faint, and in I, 1 not distinguishable.
In I, 4 and 5 the line joining the anal and gonopore centres is
parallel to the peristome; but in I, 2 and 3 the gonopore is slightly
nearer the peristome. It is always to the left of the anal plane
(cf. Text-fig. 8).

Dr. F. A. Bather—Notes on Yunnan Cystidea. 587

The actual Base of Attachment is well shown in I, 2 and 6; it is
slightly expanded, very slightly excavate, and in I, 5 is extended in
the anal plane. The ‘“‘stalk” is not a specialized stem, but merely
a narrowing of the theca; in I, 6 and 7, however, the plates in the
lower part of the theca are arranged transversely; and this is
marked, especially in I, 6, by a transverse alignment of the pore-
tubercles.

There is little to add to Dr. Reed’s full account of the plates and
their structure. The diameters of the plates in I, 1 range from
‘7mm. to 65mm. There is an occasional tendency for a large plate
to be surrounded by smaller ones. The diplopores have already
been discussed (p. 512, Text-fig. 5). The inner face and the
margins of the plates are not exposed.

Sinocystis yunnanensis Reed.

Of the four specimens mentioned by Dr. Reed, the three figured
ones have been studied, viz. I, 9,10, and IJ, 1. Of these I, 10 is
certainly identical with No. II in Reed’s table of measurements ;
but, since his measurements are estimated, his No. I cannot be
identified. ‘‘The largest,” he says, ‘‘is the best preserved”;
probably this is I, 9. But II, 1 is hereby selected as Holotype,
because it seems to show the openings more clearly than do the
others.

The following are actual measurements in millimetres :—

Specimen . ; 9 i 10 1
Height ~.. F : 97-0 44-0 76-0
; ; f See lOn 35-8 ? 0° 65:0 25°
Greatest diameters 1 37-0 110° 97-4 990° 30:6 110°«
Diameters at base . { ; :
Peristome plane . : 290° 290° 105°

(For explanation of angles, see under S. loczy?.)

The cover-plates are relatively large, irregularly triangular,
alternating, and interlocking.

Hydropore-slit concave towards peristome; its middle line about
3°2 mm. from middle line of peristome in II, 1, a little furtherin I, 9.

The Anal pyramid is seen in II, 1, its centre 20 mm. from edge of
peristome; diameter of hexagon, side to side, 5°65 mm.; height above
general surface, about 2'°2 mm.

Gonopore seen in IJ, 1, at 7-7 mm. to left of anal centre.

The Basal Attachment is seen only in I, 10; it is somewhat
cylindrically excavate along its greater diameter, which corresponds
approximately with the shorter diameter of the theca and with the
peristome plane. The theca is rather sharply bent over on its stalk,
apparently to the left, so that there was a mechanical advantage in
this shape of the attachment.

The plates may attain a diameter of about 7mm. in the larger
specimens. They are about -7 mm. thick in the middle region of
II, 1. ‘Their margins are irregularly crenelate, especially on the
inside edge. The crenelle do not appear on the outer suture; they
are in no relation to the diplopores.

Specimen 2 3 5 6 7 8 9 OR es
Height ./| 62:0 | 68 + 60 46-5 46:8 | 34-0- 69 + 65:0 58 + | 48-5 +
Greatest | 43-0 115° | 39-8 295° | 39- 6 295° 30:0 210°} 25:2 |22-2 20°/ 46-5 0° | 45-0 170° | 40-4 295° | 30-9 25)
diameters] 29:0 25° | 24-0 27:0 |27-02100°} 24:8 | 20-6 120° | 80:0 90° | 25-0 80°| 24-8 25° | 26-5
Diameters | 5:8 6:4 not cae 5-1 4:8 not pre- | not pre- | not pre- | 6:0
at base 5:4 5:7 served 4:0 broken | served | served | served | 5:5
broken broken broker
Peristome 295° 295° 295° | ? 100° 100° 95° 95° 100° 295° | not pre
plane | | served

5388 Dr. F. A. Bather—Notes on Yunnan Cystidea.

The diplopores have already been discussed (p. 512); in spite of
their radiating arrangement they never cross a suture. The canals
pass in a straight line vertically or obliquely through the plate,
emerging on the inner face in marked depressions, between, which
the surface is raised in irregular prominences.

Stnocystis mansuyt (Reed, 1917, sub Ovocystis). (Text-figs.
3, 4, 6, 7, 12 13.)

Of the ‘‘nearly sixty specimens’? mentioned by Dr. Reed the
ten figured ones have been studied, viz. II, 2 to 11. None of these
seems to correspond with either I or II of Reed’s table of measure-
ments, which indicate much larger individuals; but II, 6 corresponds
fairly with his III. Although one of the smaller individuals, this
specimen is one of the more complete, and is therefore hereby selected
as Holotype.

The. following are actual measurements in millimetres :—

(For explanation of angles, see under S. loczyt.)

The crushing makes it difficult to get the orientation, and in
several cases the anus is not preserved or not clearly seen. There
appears, however, to be little variation in the angle formed by the
peristome plane with the anal plane; it is between 95° and 100°.

As may be seen from Dr. Reed’s pl. II, figs. 7, 8, and less clearly
from figs. 6, 9, the relative positions of the thecal openings are as in
S. loczy?; a line drawn from the anal centre through the hydropore
would approximately coincide with the line of the left anterior
food-groove.

Reed’s figs. 7 and 8 also show that the branches of the subvective
system are not really equal. As in S. loczyi, the left posterior
branch is the longest, and the right posterior is the shortest
(specimens 6, 7, 8).

The angle at which the branches of each pair diverge may in some
specimens be 60°-90° as stated; but as measured in the figured
specimens, it varies between 90°, asin the left pair of II, 7 and 9,
and 140°, as in the right pair of 7; in the right pair of 9 it is 130°;
and in 8 itis 105° on the left, 106° or more on the right. These
measurements are confirmed by Mr. Brock’s drawings.

The Brachiole-facets are far from clear, so that one does not like to
lay too much stress on the occasional sugeestion a two facets to the
branch, as in S. loczyi (see Reed, pl. ah fig. 8, r. ant. branch),
especially since Dr. Reed does not mention it. Note in fig. 8 how
very close the diplopores are to the food-grooves (also our Text-
fig. 12). The elevation of the thecal plate on which the facet
rests is, in this species, called by Dr. Reed an ‘‘ oral boss”? : would
not ‘‘ brachiole boss’’ or ‘‘ facet boss” be more appropriate ?

iesaslsh

Dr, F. A. Bather—Notes on Yunnan Cystidea. 539

The cover-plates are perhaps a trifle heavier than in the other two
species, and are swollen. A section across the grooves is afforded
by II, 7 (Text-fig. 12).

The Hydropore-sht (Text-fig. 13) is almost straight, has thickened
edges, and the lumen expands slightly at the two ends (II, 2, 8, 9);
in 5 it is covered by an attached object like the lower valve of a
brachiopod; and in 10 it is crushed close up to the peristome.
Dr. Reed describes it as ‘‘ parallel to the mouth in a line joining the
right and left anterior [i.e. posterior] oral bosses’. It would
perhaps be even more exact to substitute the words “ brachiole
facets’’ for ‘‘oral bosses”, and to note that the line joining them is
not quite parallel to the peristome, but further from it on the left
side. Also the hydropore approaches this left end, and thus its
deviation from perfect symmetry with reference to the peristome is
in the direction of symmetry with reference to the left anterior
food-groove. The bearing of this on the nature of the primitive
symmetry is the same as in S. loczyi (see p. 535).

Myre length of the) slit is 45mm, im Il, 2)-/2-3.mm: in: 16):
‘9mm.in II, 7; 3:8mm. in II, 8; 4:4mm. in II, 9. Dr. Reed’s
numbers are presumably over-all measurements.

The Anal pyramid, according to Dr. Reed, is pentagonal. No
doubt this is correct for most of the specimens, but in the figured
specimens if was not so clear to me as to Dr. Reed and Mr. Brock.
My notes run: ‘‘In II, 8, about 16mm. from peristome, hexagonal,
but covered by a base with stem 4mm. long, 6:1 mm. wide below,
34mm. wide above; diameter of pyramid, side to side, ca. 5°7 mm.
In II, 6, 10mm. from peristome, ? hexagonal or pentagonal, diameter
ca. 5 mm., rather elevated—say, 13mm. Elevated about 15mm.
in II, 7?

The Gonopore lies to the left of the anus, distant from the anal
centre by 6°6mm.in II, 6; ca.9mm. in II, 8. In 8 it is elevated
above the general surface ca. 1:5 mm. and has a diameter at the top
of 16mm. ‘The diameter of the lumen is ca. 1mm. in II, 8;
"6mm. in IJ, 5 and 6. In 6 the lumen is clearly pentagonal.

The stem-like appearance of the Base is rather more pronounced
in such specimens as II, 2 and 6 than it is in S. loczyi; but it is
approached by S. yunnanensis, 1,10. Owing to its sudden contraction
and projection from the ege- shaped theca, it has been broken off in
most of the (figured) specimens. ‘This enables one to give the
following additional measurements in millimetres :—

Specimen . : : ; 3 5 6
Thickness of plates . ; ; 0-85 1-8 0-9
Diameter of lumen . é : 4-6 1:6 ca. 2°5

From these it follows that the plates increase in thickness as the
lumen contracts towards the distal end.

The base in II, 11 (see Reed’s figure) is built of five sub-equal
plates, about 3mm. high, slightly broken below. ‘These are
succeeded by a circlet of seven plates.

The thickness of the plates, as measured in II, 10, a little above
the base, is ‘Smm. ‘The plates are described fully, and figured

540 Dr. C. W. Andrews—Fossil Mammals from Salonica.

accurately by Dr. Reed; but it may be added that the sutural edges
are faintly crenelate (II, 2), and this appearance, though not
specifically mentioned by him, may have, consciously or unconsciously,
prompted his belief that subvective grooves ran along the depressed
sutures.

JiJ.—Norsz on somes Fosstr Mammats From SaLonica AND ImBROS.

By C. W. ANDREWS, D.Sc., F.R.S. (British Museum, Nat. Hist.).
(Published by permission of the Trustees of the British Museum.)

de several occasions during the War, officers on active service 1n

the Near East have found time to collect a few fossils, some of
which have been sent to the British Museum. In three cases these
were remains of mammals, and these discoveries are of importance
as indicating the existence of bone-bearing deposits in localities
where they were previously unknown, and where, not improbably,
they may prove to be as rich as the well-known bone-beds of Samos
and Pikerm1.

The most interesting specimen from near Salonica is a nearly
complete right maxilla, with portions of the premaxilla and jugal,
of a very large species of Hyena. This fragmert is in a beautiful
state of preservation: the second, third, and fourth premolars are
entire, while the canine and first premolar are represented by their
sockets and the first molar by its outer root. The bone is hard and
nearly white, with irregular patches of black stain which give it
a peculiar piebald appearance: some specimens from Maragha are
in an almost identical state of preservation. An incomplete skull
and other fragments of Hipparion from the village of Dudular,
N.N.W. of Salonica, are in exactly the same condition, and no doubt
the Hyena jaw was from the same deposit (see Text-figure, p. 541).
This fixes the age as Upper Miocene, and therefore contemporary
with the bone-beds of Samos, Pikermi, and other localities in which
the Pontian fauna is found.

In front the bone is preserved as far as the suture with the
premaxilla, a narrow strip of which remains. Above, the - facial
portion is somewhat incomplete, while posteriorly the bone joins the
jugal, which bears a blunt, somewhat forwardly directed postorbital
process. Above the canine the surface is very convex owing to the
very large size of the alveolus of that tooth. The relatively small
antorbital foramen is situated vertically above the anterior root of
p.m. 3. The lower border of the orbit, so far as preserved, differs
from that of other Hynas with which it has been compared
(H. crocuta, eximia, ete.) in being less sharply separated from the
facial surface, but passing into it by a gentle curve; the postorbital
process of the jugal also differs in being blunt and turned forward,
instead of pointed and more or less turned backwards: unfortunately
this region is wanting in the type of H. brevirostris, Aymard,' to
which the present species is in some respects similar. Judging
from its alveolus the canine must have been a very large tooth,

1 Boule, Annales des Sciences Naturelles, Zoologie, vol. xv, p. 85, pl. i,
1893.

Dr. C. W. Andrews—Fossil Mammals from Salonica. 541

larger proportionately than in the other Hyzenas; it measured about
25 mm. across at its root, and its hinder border is separated from the
small round alveolus(diameter 6 mm.) for p.m. 1 by an interval of 8 mm.
P.m. 2 is separated from p.m. 1 by a space of about 4mm.; it differs
from p.m. 2 in 7. brevirostris, with which it is comparable in size,
in not having the cingulum developed on its anterior or external
faces, and in the much smaller size of its posterior accessory cusp ;
the tooth is also less conyex on its outer face. P.m. 3 is similar in
most respects to that of H. brevirostris, but narrows more towards its
posterior end where it has a Jarger accessory cusp. The long axes
of these two teeth are in the same straight line. P.m. 4 (the
earnassial) is much like that of H. brevirostris, having a well-
developed inner cusp (protocone), which distinguishes it from the
contemporary H. eximia. In H. gigantea, Schlosser,’ a large Hyena

j ef j LA Hit fl PT
aH tN i pas ' NW,
ee niet mT of i i wey
ay a
Has

i)
Wy

Pr3.

f
|
Vem ||
/

Prt

Right maxilla of Hyena salonice, n.sp. p.m. 1, socket of first premolar ;
p-m. 2-4, second to fourth premolars. One-half nat. size. From the
Upper Miocene, near Salonica. :

from a bed of similar age in China, there is only a greatly reduced

inner cusp in p.m. 4. M.1 is represented by its outer root only,
but was probably of considerable size as in A. brevirostris, and much
larger than in HZ. erocuta, where it is very small or even wanting.

The dimensions (in millimetres) of the teeth in the present species
and in H. brevirostris are—

Hyena salonice. Hyena brevirostris.

Length. Width. Length. Width.
pms2 sche UiaDss 15 22 16
p.m Ss 67.5528 19 27 21
p.m. 4 eeRAD 25 44-5 25

The length and width of the carnassial (p.m. 4) in Hyena gigantea,
Schlosser, are 44mm, (?) and 25 mm. respectively.

As will be seen from the above measurements, this very large
species is comparable in size with Hyena brevirostris, Aymard, and
H. gigantea, Schlosser. From the former it is distinguished not only

1 Schlosser, Abhand. bayer. Akad. Wissensch., Bd. xxii, p. 35, 1906.

542 Dr. C. W. Andrews—Fossil Mammals from Salonica,

in the several structural points referred to above, but by its much ~
earlier date, H. brevirostris occurring in Upper Pliocene beds in
France, associated with Lquus stenonis. Hyena robusta, Weithofer,}
from the Val d’Arno, is regarded as identical with ZH. brevirostris.
From H. gigantea our fossil is sharply distinguished by the characters
of the upper carnassial. ‘There seems no doubt that the present is
a new species, for which I propose the name Hyena salonice, n. sp.,
the type-specimen being the right maxilla (B.M., No. M. 114138)
above described and figured : it was collected by the ‘Rev. Wilberforce
Cooper, C.F., and reached the Museum through the agency of Cyril
Brett, Esq., in 1916.

The remains of Hipparion, as already noted, are from the village of
Dudular, N.N.W. Salonica: they were collected by Capt. Seymour
W. aries R.A.M.C., and presented by him to the Museum. The
specimens (M. 11585-6) include the occipital portion of a skull,
both maxilla, premaxille, symphysial portion of mandible, and
some fragments of limb-bones.

The portions of the skull seem to have belonged to a rather large
individual, which, judging from the presence of a well-developed
canine, was probably a stallion. The teeth are in a most perfect.
state of preservation, at least on the right side, where the outer coat
of cement, so often lost, is completely preserved. There seems to be
no doubt that these remains are referable to the widely-spread
species Hipparion gracile.

The length of the molar-premolar series is 149 mm., and the width
across the occipital condyles is 78mm. The limb-bones are
represented by portions of tibiz and of a radius and ulna.

All the above specimens terminate in sharp, clean fractures,
indicating that much was left behind, and that careful collecting
might yield very important results.

Portions of a mandible and limb-bones of a large Mastodon from
the island of Imbros, off the mouth of the Dardanelles, were
collected by Lieut. Riffault, R.A.M.C., and Col. Girvin, A.M.S.,
and were sent to the Museum by Capt. Percival T. Eniesbhye
M.B., R.A.M.C., in 1916 (M.11587-8).

The remains found in this case are unfortunately very imperfect,
and were enclosed in a very refractory matrix. The chief specimen
is the imperfect right ramus of a mandible with one broken molar
in situ. This tooth seems to have been trilophodont: the outer
lobes are worn into a trefoil pattern, the ends of the trefoils being
formed by cusps blocking the transverse valleys, as in such forms as
Tetrabelodon angustidens. The bone is broken away immediately
behind the tooth, but extends in front of it as far as the posterior
part of the symphysis, the length of which cannot be determined.
The ramus is deepest at the back, narrowing gradually towards the
symphysis. The sharp alveolar border is nearly straight, while the
ventral border curves down slightly at the symphysis. There is
some evidence that there was a lower incisor of considerable size, and
in that case the species would be referable to the genus Zetrabelodon.

1 Weithofer, Denksch. Akad. Wissensch. Wien, Bd. lv, p. 346, 1889.

Chief Sources of Metals in the British Empire. 543

Very probably it is Z. penéelicus, a form described by Gaudry * from
Pikermi.

The length of the portion of the mandibular ramus preserved is
537 mm.; its depth behind the molar 170mm. (app.), the depth at
the posterior end of the symphysis 145mm. ‘The length of the
molar so far as preserved is about 120mm. The glenoid end of
a scapula, in which the long diameter of the glenoid cavity is
roughly 175mm., and part of a tibia were also collected. Numerous
other bones seem to have been noticed in the same deposit, which is
on and near the beach, and the locality is one which may prove of
great importance, although the matrix is much harder than that
of the probably contemporary bone-bed of Samos, and the difficulty
of obtaining good specimens consequently greater.

IV.—Tue Imerrmat Insrirure Map oF THE CHIEF SOURCES OF
Merats in tHe Brivish Empire.’

f{\HE Imperial Institute, in continuation of its publications with

reference to the mineral resources of the Empire, has now
issued a map with diagrams indicating the sources within the Empire
of the chief metals of commercial importance. The outline map
shows the occurrence in each British country of the important
metallic ores and also the existence of deposits at present unworked.
The locality for each occurrence is not given in detail, but only
a general statement, carried out by printing the names of the metals
therein found in large type across the face of the country. Asterisks
indicate existence of unworked deposits in producing countries,
while brackets show the existence of unworked deposits in non-
producing countries. Diagrams are also given, showing in a graphic
form the production of metal or ore in each producing country ;
these statistics are given for the year 1915: since that date many
and important changes have occurred, although no doubt it would be
difficult, if not impossible, to obtain complete and reliable figures for
the later years. The diagrams also show in an instructive manner
the relation of the output of the British Empire to those of other
countries of the world. The facts here set forth, when carefully
studied, afford much food for reflection.

In the first place it is to be noted that practically every British
country, colony, or dependency produces metal or ore of some kind
or another, and the British Empire as a whole is a producer of nearly
every metal of practical importance, the only really notable excep-
tions being platinum and mercury; for these we are entirely
dependent on foreign supplies.

One of the most striking features disclosed is that more than half
the total production of gold of the world comes from within the
British Empire, the largest producer of any country being South
Africa; the annual value of the gold output of this region is now
in the neighbourhood of £40,000,000 per annum. Unfortunately,

1 Gaudry, Animausx fossiles et Géologie de V Attique, 1862, p. 142.
2 With diagrams of production for 1915. Published by the Imperial
Institute, 1918. Price mounted on linen 5s. 6d.

544 The Imperial Institute Map

owing to the prevailing abnormal economic conditions, gold-mining
is now labouring under peculiar difficulties, since gold is the only com-
modity whose price cannot fluctuate; hence, while mining costs
rise, the selling price cannot be increased to correspond. For this
reason some low-grade propositions have been obliged to shut down,
and the total output has fallen off. Since the Rand mines work on
a very small margin of profit, they have been specially hardly hit by
these untoward circumstances, and some form of Government
subsidy has been suggested asa remedy. It is to be noted that gold
occurs in every country of the Empire, even in the British Isles,
though the amount now actually mined in the latter is very small
indeed. On the other hand, Australia, Canada, and India are all
the homes of well-known gold-fields. From the mineralogical point
of view one of the most interesting occurrences is the telluride gold-
ores of Western Australia; this is a rare type, but is known also in
Colorado and in Hungary.

Of silver the British Empire yields between one-fifth and one-
sixth of the world’s annual supply, Canada being an easy first in
this respect with 26,600,000 oz., Australia coming next with
8,780,000 oz. South Africa and New Zealand show rather under
a million ounces each, while the rest are nowhere.

Perhaps the most striking fact in the mineral wealth of the
Empire is the dominant position held by it in the tin industry. Out
of a total annual yield of about 100,000 tons, in 1915 the Empire
produced 67,000 tons. As is well known, tin has now reached
fabulous prices, and the value of this output is very great. The
Malay States alone are responsible for nearly 50,000 tons of tin,
thus yielding considerably more than all the rest of the Empire put
together, and half the total world’s output. The other important
British tin-fields are the United Kingdom, Queensland, and Nigeria.
In Cornwall there has lately been a considerable recrudescence in
tin-mining, and this has been assisted to a certain extent by the
tungsten boom.

In lead and zine Australia easily takes the lead over all other
British countries, producing about three-fourths of the lead and-nine-
tenths of the zinc. <A very large proportion of this comes from the
wonderful deposits at Broken Hill in New South Wales. A very
notable recent addition to our resources of these two metals is the
Bawdwin Mines in Burma, which are now undergoing rapid develop-
ment and seem likely to become an important increment to the
world’s supply in the immediate future.

With regard to nickel the facts are very striking. There are only
two really important nickel fields in the world, namely Canada and
New Caledonia. In 1915 Canada yielded almost exactly three-
fourths of the nickel of the world, mainly from the well-known
occurrences at Sudbury in Ontario. This has been frequently
described and is of great scientific as well as economic interest.
A promising occurrence of a somewhat similar nature has lately been
discovered at Insizwa in Zululand, and it is hoped that when con-
ditions improve this may also turn out to be a practicable source of
nickel. It seems probable that in the immediate future cobalt will

of Chief Sources of Minerals in the British Empire. 545

to a certain extent replace, or at any rate help to economize, supplies
of nickel; the two metals are very similar in their properties, and
for some purposes cobalt is actually superior; cobalt alloys, such as
stellite, are already used for a good many purposes.

eigeagt eat os

Iron ips a
Magnganese) se Pya
PIES ree Ke tO
| Ue Gord, |
In, Coppe
(Lead)

a (Zinc)

Gold* Silver* Antimony*

pad™ Coppers Tungsten™
Ainc* Bismuth* G Aromuium x
iF Mercury’ Flatinum*
ron* Iridium . Manganese
Molyhdenurm™ (Vana us)

om (Aluminium)

Note.—In the large sheet-map of the British Empire each British possession is
coloured pink, and the names of the various minerals found are printed on
or adjacent to the same county as shown in the above map of Australia,
taken from the large world-chart.

It is hardly necessary to enlarge on the importance assumed by
tungsten in the last four years as a munition of war. Until 1914
the tungsten metal industry was almost entirely in German hands,
although the greater part of the ore was obtained from the British
Empire and the United States. For atime Burma was the largest
producer, but is now surpassed by the United States. Some
countries already show signs of exhaustion, partly owing to
improvident methods of mining in the last four years, but it seems
probable that certain newly opened-up localities, such as China,
Korea, and Manchuria, will be able to yield a good supply for many
years to come. In addition to Burma, the Empire also possesses
important tungsten resources in the Malay States, Australia, and New

DECADE VI,—VOL. V.—NO. XI. 35

546 Reviews—Bennettitean Cones, British Cretaceous.

Zealand, while there is also a prospect of considerable development in
the scheelite deposits of Rhodesia. In the last few years there has
also been an increased demand for molybdenum and vanadium for
the manufacture of special steels. The price of molybdenum is now
very high, and important deposits are being worked in Canada and
New South Wales.

Turning now to the highly important subject of iron ores, some
interesting facts are revealed. In the first place it is shown that
the British Empire yielded in 1915 only about one-tenth of the
world’s output, but the most notable fact is that the United
Kingdom alone produced approximately seven-eighths of this,
namely 14,235,012 tons out of a total of 15,890,827 tons: Among
British colonies by far the most important source of iron-ore is
Newfoundland; the Wabana mines in that island are among the
largest in the world and the reserves: are enormous. Shipping
facilities are also very good and prospects are most brilliant.
During the War years very special efforts have been made to keep.
up the supply of British ore in order to save transport, and the
efforts of the Ministry of Munitions have been successful in this
respect. Important developments have taken place, particularly
among the Jurassic ores of the Midlands, and improved methods of
mining and transport have been introduced. Efforts have also been
made to develop home resources of manganese: in 1915 India
produced more than half the manganese ore of the world and
practically the whole of the output of the Empire, other British
countries accounting for only 6,000 tons. In chromium ore
Rhodesia takes the lead with nearly one-third of the world’s output,
while Canada comes next. ‘he chromite deposits of Unst, in the
Shetland Islands, have recently been worked to a considerable
extent.

From the facts above detailed it will be seen that the British
Empire plays no mean part in the world of metals. In the case of
most of them it occupies a position of prominence, and in some
of pre-eminence. Furthermore, it is known that in many parts of
the Empire there are large undeveloped, or partially developed,
deposits forming a reserve for the future. It is to be hoped that in
the period of reconstruction and development which will in all
probability succeed the past disastrous years, those who control such
matters will be inspired to adopt a wise and prudent policy, taking
into account conservation as much as development, and thus laying
the foundation of a long-continued period of prosperity and happiness
for the inhabitants of the Empire. RARER:

RAV LEws.

I.—New BennerrirEan Cones From THE BririsH Cretaceous. By
M. C. Sropes. Phil. Trans. Roy. Soc. Lond., ser. B, vol. cevii,
pp. 389-440, 6 pls., 25 text-figs., 1918.

ROBABLY no genus of Mesozoic plants has excited such interest
among botanists as Bennettites, or, as Professor Seward and
others prefer to call it, Cycadeoidea. This interest was greatly

Reviews—Yorkshire Type Ammonites, - BAT.

stimulated by the results of Wieland’s study of a large number of
American fossil Cycadophytes, which were thought by some workers
to throw light upon the vexed question of the origin of the
Angiosperms. A full knowledge of these plants is thus particularly
desirable, and we must welcome descriptive work dealing with
them, even when—as is the case in the memoir before us—the
author has not been so fortunate as to add anything of material
importance to what was already known.

The first section of Dr. Stopes’ paper consists of a description of
a portion of a cone, Bennettites albianus, sp. nov., recently obtained
from the Gault of Folkestone Warren. The specimen was petrified
and proved suitable for sectioning. ‘The author concludes that this
cone was ‘‘the giant fruit of the family”’. ‘The fragment available,
however, measured only 5°5 cm. X 38cm. in transverse section, and
the idea that the cone was of peculiarly large size is deduced from
a reconstruction of its probable shape when complete; this may be
perfectly correct, but it must be regarded as at present scarcely
proven. The seeds with their embryos and seed-coats, and the
interseminal scales, are discussed and figured in detail. ‘The author
describes the outermost layer of the seed covering as a ‘‘cupule” or
‘‘aril” of elongated tubular cells. She regards the plug of tissue
closing the micropyle as nucellar in nature.

Carruthers’ type-specimen of Bennettites maximus has hitherto
been known only by its external characters, and so much of its
anatomy as could be observed with a hand lens. In the second part
of her paper Dr. Stopes records the results she has obtained by
having this specimen sectioned. ‘The most notable feature is the
occurrence of extremely young cones. One of these, of which
preparations were obtained, shows in one section a collar of tissue
surrounding the peduncle, which the author interprets as a whorl of
male sporophylls. She writes: ‘‘ The discovery that this species had
bisporangiate cones is, of course, the feature of supreme interest in
the plant.” When we consider, however, that the existence of
male sporophylls is deduced from a single section in which no
synangia are preserved, we can scarcely avoid feeling that, although
the truth of Dr. Stopes’ view is highly probable, it must at present
be received with some degree of reserve.

PAG ae

IIJ.—Yorxsuire Type Ammonites. Kdited by 8S. 8S. Buckman;
photographs mainly by J. W. Turcnuer. Part XVI. 8 plates,
and descriptions Nos. 112-116. London: Wesley. 1918.
Price 3s. 3d. net.

(J\HE present part of this most systematically edited publication

deals with five Ammonite species: Arnioceras semicostatus
(Young & Bird); Perisphinctes rotifer (Williamson-Brown); Hildo-
ceras bifrons (Bruguiére); Pachyceras rugosus (Leckenby); Vertumni-
ceras vertumnus (Bean-Leckenby). This last is a new genus_of the
family Cadoceratide; of the four paratypes of the species (which,
with the holotype, are in the Sedgwick Museum) two are referred to

548 Reviews—The Ossiferous Caves near Torquay.

Quenstedticeras damont, Nikitin, and a third is made holotype of
Vertumniceras spatiatum, n.sp.

Of the species herein dealt with, Hi/doceras bifrons is probably the
best, as it is also the longest, known. Mr. Buckman thinks it highly
probable that the specimen represented in his plate cxiva is the
original of Martin Lister’s figure (1678, Hist. Anim. Angl.), which,
through Bruguiére’s reference to it, became the holotype. The
specimen is now in the collection of Mr. V. KE. Robson, F.G.S., who
‘purchased it in London”. London is a big place, so that this
statement does not throw much light on the previous history of the
specimen. Indeed, our friend Mr. S. Holmes, Intelligence Depart-
ment, regards it as a transparent blind.

IiI.—Tue OssirErous Caves nuar Torquay.
ie the Journal of the Torquay Natural History Society for 1918
i. Mr. Harford J. Lowe has given an interesting account of the
comparatively little-known Tor Bryan Caves, near Torquay, together
with a short biography of Mr. J. L. Widger, who spent some twenty
vears of his life in excavating them. Unfortunately his enthusiasm
appears to have been greater than his knowledge of what is required
in making such an excavation, and consequently much valuable
information has been lost. Mr. Lowe discusses the probable history
of the caves and their relation to Kents Cavern and Brixham Cave.
He considers that the human occupation of these caves was much
later than that of Kents Cavern. The greater part of the Widger
Collection is now in the British Museum.
F. A. B.

IV.—Rerort on CERTAIN MINERALS USED IN THE ARTS AND
Inpusrries. III. Maenxstrz. By P. A. Waenzr. South
African Journal of Industries, Pretoria, 1918.

N this bulletin Dr. Wagner gives a general account of the
properties and uses of magnesite and describes the occurrences of
the mineral in South Africa. Since the supplies from Austria-

Hungary and Greece were cut off by the War a considerable

magnesite industry has developed in Canada and California, largely

for use as a lining in basic open-hearth steel furnaces in the form of
bricks. It is also much employed in the manufacture of cement
for various purposes, such as floors and ceilings. For all these uses
it must be fairly pure, and the supplies of really good quality
material are somewhat limited. Up to the present magnesite
mining in South Africa has been confined to the Barberton district,
where it is found in considerable quantity in the basic and
ultrabasic igneous rocks of the Jamestown series. There are also
important deposits in the valley of the Olifants River, in the

Lydenburg and Pietersburg districts, as veins in highly decomposed

pyroxenite belonging to the Bushveld complex. The material

produced is now for the most part used by the Union Steel

Corporation for linings of electric furnaces at Vereeniging. Other-

wise the local demand is small and the establishment of an export

trade does not at present seem probable.
Tiss) gy 1h

Reviews—Corundum of the Zoutpansberg Fields. 549

V.—Tue Corunpum or THE ZouTPANSBERG FIELps AND ITs Marrrix.
By P. A. Waenrer. Trans. Geol. Soc. 8. Africa, vol. xxi,
pp. 37-42, with 4 plates, 1918.

OUTH Africa now ranks as the leading country in the production
of corundum, having an output of about 400 tons per month.
This comes chiefly from the Zoutpansherg and Leydsdorp fields.
The greater part of the mineral occurs either as eluvial crystals and
fragments, or as ‘‘boulder’’ corundum, that is rock-fragments
containing it along with other minerals. In this paper the
characters of the corundum crystals are fully described and analyses.
given. It is shown that the mineral occurs as a constituent of
a pegmatite of dioritic type (plumasite-pegmatite) intrusive in the
Swaziland series and in various dioritic and gabbroid rocks, probably
belonging to the same phase of igneous activity.

ViI.—Conrrisutions To THE Muineratocy oF Brack Lake Area,
Quresre. By E. Porrevin and R. P. D. Granam. Canada
Department of Mines, Geological Survey, Museum Bulletin
No. 27, pp. 82, with 12 plates and 22 text-figures. Ottawa,
1918.

fee Black Lake area is situated in Megantic county, province of

Quebec, and includes one of the most productive portions
of the great ‘‘serpentine belt”. Mining is carried on for asbestos
and chromite, and in the course of these operations many interesting
minerals have been found. Besides serpentine, other igneous rocks
are found, including pyroxenite, gabbro, granite, and aplite, as well
as other more basic varieties. The minerals include sulphides,
carbonates, and a large variety of silicates: only a few of the more
interesting types can be mentioned here, such as very well-developed
erystals of diopside, garnet, vesuvianite, zircon, stichtite. Many of
these minerals are rich in lime and are believed to be partly due to
magmatic concentration after differentiation of an igneous magma,
the solutions thus formed circulating through the rocks and reacting
with their earlier constituents.

BEC EG.

VII.—Awnatyses or Canapian Fuers. Part I: Tae Maritime
Provinces. Part IL: QursEec anp Ontario. Part IIT: Manirospa
AND SaskatcHewan. By E. Sransrrerp and J. H. H. Nicotts.
Canada Department of Mines, Bulletins 22, 23, and 24.
Ottawa, 1918.

fy sectan Bulletins consist of a collection of analyses of coal, peat,

oil, oil shale, and natural gas from a large number of localities
within the areas specified. The work has been in progress for
several years, first at McGill University and afterwards at the
Department of Fuels and Fuel-testing, Mines Branch, Department
of Mines, Ottawa. The data given are proximate and ultimate
analyses, calorific value, fuel ratio, and carbon-hydrogen ratio. The
geological relations of the different deposits receive only the briefest

550 Reviews—The Geology of Vancouver and Vicinity.

mention, ‘but: the figures given will be very valuable to those
interested in the study of fuels.

VIII.—Tae Gxotocy or Vancouver anv Vicinity. By E. M. J.
Burwasa. pp. 106, with 23 figures and 2 maps. Chicago, Ill. :
The University of Chicago Press. 1918.

f{\HE area covered by this report may be divided into two parts:

the southern portion, which extends from the international
boundary to Burrard Inlet, is part of the floor of the great structural
valley in which lie Puget Sound and the Gulf of Georgia; the
northern area forms part of the southern margin of the coast range
of British Columbia. In the latter the relief of the land is high and
yields a definite record of a succession of physiographic cycles. Five
such stages can be recognized and correlated with those already
worked out in the Cascades of Washington State; they are as
follows: the Methow peneplain, represented by accordant summits
and terraces, the Entiat stage when mature valleys were developed
in this older surface, the Twisp stage when the Entiat valleys were
over-deepened by canyons cut in their floors, after uplift, the Chelan
stage of glacial modification, and the Stehekin stage of post-Glacial
stream-denudation and deposit.

The rocks found in the region include Devono-Carboniferous
(Yexada and Britannia series), the first wholly volcanic, the second
including slate and sandstone as well as lavas, some porphyrite
intrusions assigned to the Trias, the Upper Jurassic coast-batholith,
Eocene conglomerate, sandstone, shale, and clay, post- Eocene eruptives
(Black Tusk basalts), the Garibaldi volcanic formation, and a variety
of Quaternary deposits. Of each of these detailed descriptions are
given, together with a very complete discussion of the structural and
physiographic features attending the formation of each.

The coast-batholith forms part of the immense series of pre-
dominantly dioritic batholiths extending from the Frazer River into the
Yukon territory. This particular igneous complex includes varieties
ranging in composition from biotite-granite through granodiorite,
diorite, and gabbro to hornblendite. here is clear evidence of
differentiation with marginal basic facies, the latter being in some
places intruded by more acid apophyses. Near the contacts gneissoid
texture, due to flow, is in evidence, and orbicular types are also known.
The Black Tusk basalts form the summits of certain conspicuous
mountains, these being probably remnants of flows that filled
a Miocene valley, while similar rock-types occur elsewhere as dykes.
The Garibaldi volcanics form three cones which are clearly later than
some of the Pleistocene glacial deposits: they are mainly basaltic in
composition.

Among. Quaternary deposits the moraines and various forms of
drift are: the most noteworthy, since they indicate several stages
of glaciation of the region. There are also numerous examples
of deltaic and other alluvial deposits, as well’*"!erraces which the
author considers to have been formed by glacial lukes.

Reviews —_N, ew Zealand Geology. 551

1X.—Tue Rorror Gracirr Laxes (PiepMonrese Axps). By C. S.
Dou Ricue Pretier. Scottish Geographical Magazine, vol. xxiv,
pp. 3380-342, with 5 text-figures, 1918.

(has author gives a detailed description of several small lakes,
some of very recent origin, formed in the course of the retreat
of the Ruitor glacier, either at its margin or at the frontal base of
the glacier tongue. Some of these lakes, which bear some
resemblance to the Marjelen See of the Bernese Oberland, have at
times been the cause of disastrous floods in the Dora Baltea valley.

X.—New Zratann GeroLoey.

1, Tur SrrarierapHy or THE Tertiary Beps or rue Castie Hu.
on Tretissick Basty. By R. Sperenr. Trans. New Zealand
Inst., vol. xlix, pp. 321-56, 1916.

HIS basin, which is situated in the heart of the mountain region

of Canterbury, is about 8 miles long by 4 miles wide, and
contains an interesting series of sedimentary deposits, with some
voleanic material. The strata, which consist of sands and sandstones,
greensands, shale, coal, and limestones, are richly fossiliferous.

Certain beds low in the series contain plant remains of decidedly

Tertiary character, including Quercus, Planera, Dryandra, and Cassia,

but these are overlain by marine sediments containing Cretaceous

shells. Higher still the proportion of recent forms gradually
increases, and the author considers that the succession from

Cretaceous to Tertiary is continuous, since he finds no indication of

unconformity, as maintained by earlier writers.

Test el 1a

2. An Unrecorpep Tertiary OvuriieR In THE VALLEY OF THE
Raxara. By R. Sperent. Trans. New Zealand Inst., vol. xlix,
pp. 356-60, 1916.

fYVHE author gives in this paper a description of a newly-discovered

occurrence of Tertiary strata in the valley of the Harper River,

a tributary of the Wilberforce, which is itself one of the main

feeders of the Rakaia, in the Canterbury district. The Tertiary

deposits cover an area of some 5 miles long by 2 or 3 broad, and
consist of sandy clays with impure lignite, greensands, concretionary
sands, and shell beds, the fossils indicating a mid-Tertiary age. The
occurrence of the outlier in this position is explained as being due to
faulting, the main part of the series having been removed by erosion
at higher levels. ‘he walls of the valley itself are remarkably
straight and suggestive of a rift, and are parallel to the dominant
fault-lines of the whole area, the Kaikoura fractures of McKay and

Cotton. This region also affords evidence of some interesting

modifications of drainage, which may be due either to very recent

movements along “-u''-lines or to glacial barriers.
BiB RN:

552 Reviews—New Zealand Geology.

38. ADDITIONAL Facrs coNCERNING THE DisrrisuTion oF IGNEOUS
Rocks 1x New Zeatanp. By J. A. Barrrum. Trans. New
Zealand Inst., vol. xlix, pp. 418-24, with 1 plate and 1 text-
figure, 1916.

‘W\HIS paper contains petrographical descriptions of nine specimens
of igneous rocks from different parts of New Zealand, including
both plutonic and volcanic types. A hypersthene basalt from near
Whangarei is believed to be the first instance of this rock from that
country, although hypersthene is well known in the basic andesites
of Tarawera and Tongariro. A peculiar basalt with olivine, augite,
and large phenocrysts of biotite from the Wairoa River is often used
for ornamental work and is locally called ‘‘ Kaipara granite”’.
A hornblende basalt is also noted from near Sumner in the South
Island. The plutonic rocks include a coarse-grained troctolite with
much serpentine from Wade, near Auckland, and various gabbroid
and dioritic rocks from the Baton and Graham Rivers, Nelson. These
are essentially very coarse-grained hornblende rocks with much
ilmenite, epidote, apatite, sphene, and a varying amount of quartz:
the hornblende seems to be secondary after pyroxene. Some
boulders of dioritic rocks with gneissic structure were found at
Albany, near Auckland: they probably come from a Miocene
boulder-bed. Diorites seem to have formed an important element in
the pre-Tertiary terrain of the Auckland district. A specimen of
granodiorite from Reefton, in the Nelson district, which was
apparently collected from a river gravel, is remarkable in that it
contains what appears to be primary epidote. It is a rock of granitic
appearance, with abundant biotite and a large variety of felspars,
including perthite, microcline, and plagioclase. Both sphene and
epidote are very abundant. The epidote, often occurs in well-formed
crystals enclosed in felspar or in biotite. Crystals of brown horn-
blende are often enclosed in the epidote, and the author regards
the primary character of some at least of the epidote as established.
Although the rocks here described come from widely scattered
localities and may be of very different ages, nevertheless they all
show more or less clear sub-alkaline characters. One specimen only,
from Wairau Creek, Milford, Auckland, is described as a trachyte,
and even this does not seem to be a very alkaline rock. However,
no analyses are given, so that this point cannot be decided.

R. He Re

4. Tue Votcanic Rocks or Oamaru. By G. H. Urrrey. Trans.
New Zealand Inst., vol. 1, pp. 106-17, 1918.

N this district there are three horizons of voleanic rocks—the
Waiareka tuffs, the Kakanui breccia, and an upper lava, the latter
shows many of the characters of the pillow lavas, but they cannot
be classed with the spilites, since the proportion of soda-felspar is very
low. It was, however, erupted under marine conditions, but in
shallow water. The stratigraphical breaks and the limestone
conglomerate can be explained on the assumption that voleanic
islands were rapidly formed and rapidly destroyed: hence the un-
conformities introduced into the Oamaru system by other observers

Reports & Proceedings—Geological Society of London. 553

are of merely local value, and the succession is really continuous
throughout,

5. On tHe Acre oF tHE Warkonarrr Sanpstone, Oraco, By
J. Artan THomson. ‘T'rans. New Zealand Inst., vol. 1, pp. 196-7,
1918.

OST geologists have correlated this sandstone with the Otatara

limestone, but the discovery in it of Pachymagas abnormis

leads the author to conclude that the sandstone belongs to the Upper
Oamaruian, possibly to the Awamoan.

REPORTS AND PROCHEHDIN GS.

I.—Geroxnocicat Socrury oF Lonpon.
November 6, 1918.—G. W. Lamplugh, F.R.S., President, in the Chair.

The President read a communication that he had received from
Professor Charles Barrois, D.Sc., F.M.G.S., in reply to congratulations
sent on the occasion of the evacuation of Lille by the enemy forces.

A discussion on the Antarctic Ice-cap and its Borders was
introduced by Sir Douglas Mawson, D.Sc., B.E., F.G.S.

Sir Douglas Mawson said that at the last meeting of the Society '
the subject of the Antarctic Ice-cap was reviewed in its broader
aspects, ‘chiefly with the view of promoting a discussion among
those specially interested in Glaciology. The present occasion had
been reserved for the discussion, and he proposed to show certain
lantern-slides in order to bring the salient features freshly to mind.

Though much of the foundation of the Antarctic Ice-cap is
certainly elevated land, it is quite possible that elsewhere the dome
rests upon a floor actually below sea-level. In any case it is most
probable that the smooth ice-surface masks a very irregular rock-
basement. he thickness of the ice may, therefore, be expected to
be extremely variable, no doubt reaching a maximum of several
thousands of feet.

An ice-formation of such magnitude introduces questions relating
to the flow of its substance and the abrasion of its foundations which
do not enter into the physics of ice-masses of smaller dimensions.
Here the static pressure on the lower zones of the ice may reach
1 ton per square inch. At the same time, the temperature may
be so increased by ground heat as to be much higher than that
prevailing above. As a consequence, when the ice-formation is
very thick, a more plastic base must be admitted.

The outflow of the inland ice is principally deflected at the coastal
margin into depressed areas outlining the heads of gulfs and bays.
In such localities the rate of movement and the volume of ice
entering the sea are both great. So great indeed, that extensive

1 See Reports and Proceedings Geol. Soc., June 19, 1918, GEOL. MAG.,
August, 1918, pp. 379-80.

554 Reports & Proceedings—Geological Society of London.

floating ‘‘ glacier tongues” are a feature of such situations, often
extending 40 to 50 miles from the shore.

Along other stretches of the coast less well placed for receiving
contributions from the interior of the Continent, the outflow is so
much less that the destructive influences at work on reaching the sea
easily maintain its boundaries at approximately the true coastline.

As exceptions to this latter prevailing condition, however, there
are known already two notuble localities where the general overflow
from the land maintains itself as an immensely thick floating
structure extending far out over the sea—a veritable oceanic ice-
cap. To this type of formation we apply Professor Nordenskjold’s
term ‘‘shelf-ice’’. The formations referred to are the Great Ross
Barrier at the head of the Ross Sea and the Shackleton Shelf off
the coast of Queen Mary Land.

‘The former occupies what is really the head of the Ross Sea—
a somewhat triangular area. From apex to base it measures
500 miles, with a base-length of about 400 miles. This great raft
of ice presses forward to the open sea at the rate of a few hundred
yards per annum. The available figures, quoted by David and
Priestly, show that, at the present rate of advance, the ice now
appearing at the sea-face must have left the inner extremity of the
floating sheet at some time during the seventh century. A survey of
the ice-cliff forming the sea-face indicates by its changing height
that the Ross Barrier is of varying thickness. This has been
explained by the presence, in localities where it is thickest, of the
remnants of the massive ice contribution received during its course
from certain of the large tributary glaciers. The ice from these
glaciers, in fact, constitutes a strong framework which stiffens and
contains the more crumbling structure derived from the consolidation
of the annual snowfall.

To a great extent this must certainly be so; but the influence of
a varying snowfall, and the effect of violent periodic winds—a
feature of the region—in sweeping the loose snow from certain
areas and depositing it in other favoured localities, must be reckoned
with. The snowfall is lighter on the eastern side than on the
west. Furthermore, the snow tends to accumulate on the western
side owing to the fact that the winds regularly blow from the
quarter south to east, and not from the west.

In the case of the Shackleton Shelf, this is the more remarkable
because it maintains itself as a pontoon stretching into the open
sea, even across the drift of the prevailing ocean-current.

The deluge of ice, after descending to the sea, presses northwards
as an integral whole, at first touching bottom at intervals, then
forcing its way past several islands, eventually reaching an extreme
distance of 180 miles from the land before it is mastered by the
swell and currents of the Southern Ocean. It is somewhat
triangular in form, with the apex out to sea. The base against
the land, though not completely charted, extends in all probability
for a distance of about 200 miles.

The main body of. the shelf-ice advances rather slowly, but the
Denman Glacier, which contributes to it, has a much more rapid

Reports & Proceedings—Geological Society of London. 555

movement, very well illustrated by the fact of its ploughing through
the other shelf-ice with such force that a shatter-zone some miles
wide is developed.

The wall of the shelf-ice on the west side offers an excellent
example for study, as it is a section from the point of its departure
from the land to its crumbling apex. Im the case of the Ross
Barrier, the cliff-face is a section across the direction of movement.

At the land end, the Shackleton Shelf, from the surface down, is
hard glacier-ice breaking with a characteristic fracture. A few
miles farther out, away from the influence of the winds descending
from the land slopes, a nevé mantle commences to make its appear-
ance over the original ice-formation. As one steams along the face
away from the land, this capping is observed to increase steadily in
thickness. ‘The overburden of nevé is arranged in regular bands,
each of which corresponds to a single year’s addition. This being
so, it is possible to make some sort of an estimate of the age of the
formation.

The weight of these additions depresses the top of the original
ice below the surface of the water. Though there is a regular
annual addition above, it must not be imagined that the total
thickness of the pontoon is correspondingly increased; for the
solution of the lower surface by the sea has also to be reckoned
with. Very often, however, in the nevé sections of glacier-tongues
the cliff-face above the water is observed to stand higher than in the
wholly ice zone at the land end. ‘This is to be expected on account
of the lighter nature of the nevé ice added, there being a larger
proportion of air sealed up in it.

The observed height above sea-level of Antartic shelf-ice so far
recorded ranges from about 20 toover 200 feet. A common figure is
from 90 to 120 feet, suggesting a total thickness of 600 to 1,000 feet.

Although the height of the cliff-face presented by shelf-ice gives
some idea of its total thickness, a really accurate method of
determination is badly needed. The Australasian Expedition hit
upon a method which gives positive results in some cases at least.
This consists in taking serial temperatures of the sea-water in depth
near the face of the shelf-ice. As there is always a current flowing
beneath the ice, the bottom of it is likely to be marked by a sudden
slight change in the water temperature, easily observed when the
observations are plotted as a graph.

The President conveyed the thanks of the Society to Sir Douglas
Mawson for his luminous description of Antarctic conditions and for
his selection of the magnificent illustrative photographs on this as
well as on a former occasion. The fact that the explorer was in this
case a thoroughly competent geologist was indeed fortunate. The
Fellows had been thus enabled to participate without effort in the
new knowledge gained through heroic labour by the lecturer and his
comrades. A further privilege was afforded to the Glacial geologists
present by Sir Douglas Mawson’s readiness to impart the information
that he, more than any other man, possessed, and, as time was
limited, the President hoped that the speakers would take advantage
of this privilege rather than give expression to their particular views.

556 Reports & Proceedings—Geological Society of London.

For his own part, he would like to ask at once whether the
lecturer had formed any opinion as to the origin of the evidently
bold land-features that were buried under the ice—could they have
been carved out by the ice itself, or were they the relics of a time
when the land was ice-free?

In the discussion which followed, Professor P. F. Kendall, Sir
Henry Howorth, Dr. J. W. Evans, Mr. G. W. Young, Mr. A. E.
Kitson, and Dr. A. Strahan took part.

The President supplemented the questions by asking whether the
lecturer could express any opinion as to (1) whether, if the great
table of shelf-ice continued to grow by accretion, it would eventually
become merged into the main ice-sheet; (2) how much of the
remarkable seaward extension of the huge ice-tongues was due to
forward flow, and how much to growth-in-place by snowdrift; and
(3) what happened when an advancing ice-front over-rode a rocky
island well separated from the mainland ?

Sir Douglas Mawson, in replying, said that he would take the
President’s questions first. As to the origin of the land-features,
he did not want to commit himself on this difficult point at present,
but was inclined to think that the physiography, so far as one sees
it, might all have been produced by ice. if no other agency had been
available; but it was most likely that the ice started upon a surface
already sculptured to some extent. He felt sure, however, that the
Antaretic ice could and did cut deep channels, not only above but
also below sea-level. Where the ice was thickest it burrowed
fastest, and tended, therefore, always to accentuate any existing
hollow.

As to the growth of the shelf-ice, although there was a large
accretion at the top by snow swept off thé land, there was also
probably much dissolution below by the action of the sea-water; so
that the net increase of the mass was not so rapid as appeared at
first sight.

That there was forward movement of the ice-tongues was proved
by the way in which they ploughed through the fixed shelf-ice and
by their upward bulging where they struck bottom; but most of
their movement was over sea-water, and therefore easy and almost
frictionless. |

Where the ice-sheet abutted upon an island, it depended upon the
relative proportions of ice and land whether the land was entirely
over-ridden or the ice-flow split and diverted. Examples of both
phenomena were observed.

As to the rate of wastage by melting, the great ice-plateau by
causing an outflow of cold air kept the temperature at the ice-
margin too low for much melting. What melting there was
depended mainly upon the lie of the ice-slope in relation to the sun.
There was also a good deal of wastage both of snow and ice by
direct evaporation, depending upon the season. But the main
wastage was due to the descending winds, which fiercely and almost
continuously swept the outer slopes.

With regard to the thickness of the ice, there was perhaps no
direct evidence, but a great amount of indirect evidence all indicating

Reports & Proceedings—Lwerpool Geological Society. 557

that it must in places be very thick—probably several thousands of
feet. Boring had been thought of, but would be impracticable
because of the movement of the mass at differential rates, so that the
borehole could not be kept plumb or open. There were some new
instruments, however, invented for marine purposes, which might
eventually yield positive information.

The banding of the ice was not due to dirt or dust, which was
practically absent in the Antarctic, but to differences of structure
and density, marking the seasons.

The rugged surfaces of the “islets are probably due to frost-
splintering and marine action, and do not imply that they have
suffered no ice-erosion.

The drift deposits are scanty, because there is so little flat land
exposed on which they could accumulate. But the sea-bottom
earries a great accumulation of clay with boulders for a long distance
northwards from the present ice-front.

The Secretaries of the Society are desirous of completing a record
of the services rendered by the Fellows in connexion with the
present War. Details of service, with a statement of rank, regiment,
military honours, and any other information, will be gladly received
from Fellows, either with reference to themselves or to those known
to them.

Il. Liverpoot Geronoeicat Socrery.

November 12, 1918.—J. H. Milton, F.G.S., F.L.S., Ex-President,
in the Chair.

The following paper was read :—

‘* Notes on Pebbles in their Geological Associations.” By William
Hewitt, B.Se.

The paper gave the results of a comprehensive study of the
physical characters of pebbles and their production, and embodied
a large amount of statistical and other information relative to their
sizes and shapes, the transporting power and velocity of streams, and
the varying conditions under which pebbly deposits have been
accumulated. The more important conglomerates of the geological
series were also briefly considered. Recent observations by
Mr. Hewitt as to the number and size of the pebbles (from about
one-tenth of an inch long and upwards) in the Bunter Pebble Beds
in four different localitiesin the Liverpool district, where the pebbles
are most conspicuous, gave the following result :—

Total Total No. of Longest diameter.
surface. pebbles. Uptol’’, 1-2’, 2-3'’. Over 3’.
Vertical sections - 932 sq. feet 723 676 36 10 1
Horizontal sections . 22? ,, 1,012 974 36 1 1

The greater number of pebbles shown in the horizontal sections
confirms previous observations as to the occurrence of pebbles mainly
at distinct horizons; in some cases they constitute small gravel
pockets. The majority of the pebbles were under half an inch in
their longest diameter, the largest one seen was 6 inches long. An

558 Reports & Proceedings—Mineralogical Society.

estimate of the relative proportion of the surface of section occupied.
by pebbles ranged in vertical faces from 3 to 9 per cent and in
horizontal faces from 4 to 16 per cent with one exceptional case of
32 per cent. (The percentage of the rock mass formed by the
pebbles is certainly distinctly lower than the surface percentage.)
This condition of the Liverpool Pebble Beds is in marked contrast to
the Bunter conglomerate beds of the Midlands (Cannock Chase, etc.)
or Budleigh Salterton.

II1.—Miyeratoeicat Socirery.

Anniversary Meeting, November 5, 1918.—Sir William P. Beale,
Bart., K.C., M.P., President, in the Chair.

The following were elected Officers and Members of Council:
President, Sir William P. Beale, Bart., K.C., M.P.; Vice-Presidents,
Professor H. L. Bowman, Mr. A. Hutchinson; Treasurer, Dr. J. W.
Evans; General Secretary, Dr. G. T. Prior, F.R.S.; Foreign
Secretary, Professor W. W. Watts, F.R.S.; Editor of the Journal,
Mr. L. J. Spencer; Ordinary Members of Council, Mr. H. Collingridge,
Mr. ff. Crook, Dr. G. 'F.> Herbert) Smith, Dr. He Dhomas,
Mr. H. F. Collins, Mr. J. P. De Castro, Professor H. Hilton,
Lieut. A. Russell, Dr. A. Holmes, Miss M. W. Porter, Mr. R. H.
Rastall, Sir J. J. H. Teall, F.R.S.

The following papers were read :—

Dr. G. F. Herbert Smith and Dr. G. T. Prior: ‘On a Plagionite-
like Mineral from Dumfriesshire.” Specimens of antimony-lead
ore collected by Lieut. Russell from Glendinning mine contained
small cavities lined with tiny black crystals, measuring less than
0-4mm., and mostly less than 0°2mm. across. Some resembled in
habit the crystals of plagionite from the Hartz Mountains described
by Luedecke. Measurements made on the three-circle goniometer
showed the crystals to belong to the semseyite end of the group, and
the result of a chemical analysis of the compact material of which
the crystals form part corresponded approximately to the formula
5 PbS .2Sb,8,. Semseyite has not previously been recorded from
the British Isles.

Lieut. Arthur Russell: ‘‘The Chromite Deposits in the Island of
Unst, Shetlands.’’ The bottle-shaped mass of serpentine which runs
through the centre of the island from north to south contains
chromite uniformly distributed, but varying greatly in character,
being at times massive, but generally granular. Over thirty
quarries are known, but only six of them have been worked to any
extent. The associated minerals include kammererite (abundant in
one quarry), uvarovite, copper, hibbertite, brucite, calcite, tale, and
magnetite. The rocks other than the serpentine are poor in
minerals.

Dr. G. T. Prior: ‘‘The Nickeliferous Iron of the Meteorites of
Bluff, Chandakapur, Chateau Renard, Cynthiana, Dhurmsala, Eli
Elwah, Gnadenfrei, Kakowa, Lundsgard, New Concord, Shelburne,
and Shytal.” The percentage of nickeliferous iron and the ratio
of iron to nickel in the several instances were found to be

Correspondence—L. M. Parsons. 559

respectively—5, 64; 8, 9; 84, 61; 6,6; 33, 34; 64, 74; 214, 123;
SeGeese, 5 108s TOs LOS Ge.

CORRESPONDENCE.

THE HORIZON OF PRODUCTUS HUMEROSUS.

Srr,—In reply to Dr. Wheelton Hind’s letter in the October
number of the Grorogican Macazinz, may I point out that there
appear to be two forms of Productus humerosus occurring at different
horizons. The earlier form is evidently characteristic of the
Belgian ‘‘swb-/evis”’ level (C-S), while the later mutation is found
in the Dibunophylium zone. The late Dr. Vaughan, in his paper on
the ‘‘Correlation of Dinantian and Avonian’’, published in the
Q.J.G.S., vol. lxxi, No. 281, refers to this matter, and mentions, on
p- 47, that the Clitheroe form is the early variety of Productus
sublevis. For the present I conclude, from evidence stated in my
paper, that the Leicestershire beds contain the later advanced form
of P. humerosus, and are of D, age, but I am looking forward to
reading, with much pleasure, Dr. Hind’s forthcoming paper on the
Clitheroe area, and will then carefully reconsider the question.

- L. M. Parsons.

110 LEWIN RoaD,
STREATHAM, S.W. 16.

OBITUARY.

SAMUEL WENDELL WILLISTON, M.D.
BORN JULY 10, 1852. DIED OCTOBER, 1918.

VERTEBRATE paleontology loses a distinguished student by the death
of Professor 8. W. Williston. After leaving school he entered the
Kansas Agricultural College, where his interest in geology was
roused by Professor B. F. Mudge. He was then employed by
Professor O. C. Marsh as one of his fossil-collectors in Kansas and
other western territories of the United States. At the same time
he helped with the preparation of the fossils in the Yale University
Museum, and also pursued medical studies, which eventually led to
his graduating as M.D. He was deeply interested both in the fossils
and in the living animals which he met with during his explorations,
and so early as 1877 he began to publish small notes. Professor
Marsh, however, discouraged Williston’s researches on fossils, and
he therefore turned in earnest to dipterous insects, on which he
became one of the leading authorities in the United States. In the
early eighties he was appointed Professor of Geology and Paleon-
tology in the State University of Kansas at Lawrence, where he
brought together a great collection of fossils from the Cretaceous
and Carboniferous formations of the State. In 1902 he removed to
the newly instituted chair of Paleontology in the University of
Chicago, where he continued active researches until nearly the time
of his death.

560 Obituary—Miss Maude Seymour.

While at Lawrence, Williston’s most important work was his
_ investigation of the reptiles found in the Chalk of Kansas, and the
results were finally summarized in a well-illustrated volume of the
University Geological Survey of Kansas (vol. iv, Paleontology, pt. i)
published in 1898. In his early years at Chicago he continued these
researches, and his valuable papers on Plesiosaurs and Pterodactyls
in the Publication of the Field Columbian Museum, No. 78 (1903),
may be specially mentioned. He also published a little semi-popular
volume on Water Reptiles (1914). During the last decade he
devoted attention chiefly to the Permian Reptiles from Texas and
Missouri, describing important collections which he acquired for the
University of Chicago. These form the subject both of numerous
papers and of a small well-illustrated volume on American Permian
Vertebrates, issued by the Chicago University Press in 1912. Many
of the papers not only describe the fossils, but also discuss the
bearing of the new facts on some of the most fundamental problems
' of vertebrate morphology. A complete list of Williston’s papers up
to date, prefaced by a beautiful portrait, was printed by
J. T. Hathaway at New Haven in 1911.

Williston was an attractive personality and left many devoted
pupils, of whom some have already made important contributions to
the science of which he was so successful an exponent. A.S.W

MISS MAUDE SEYMOUR.
Born 1887. DIED NOVEMBER 6, 1918.

THosr Fellows of the Geological Society who have been
accustomed to use the Library during the last few years will hear
with much regret of the death of Miss Seymour, who was appointed
as an assistant in the Library on September 1, 1915. The valuable
experience gained during several years of training on the staff of the
Royal Society’s Catalogue of Scientific Papers gave her the advantage
of a special knowledge of the literature with which she had to deal.
She devoted herself to the work with marked ability, and her
unflagging zeal and amiability of disposition substantially relieved
the pressure of an exceptionally harassing period. During this time
she gained an intimate knowledge of the work involved in the
preparation of the Geological Literature; and by her sudden and
untimely death the Geological Society has lost a valuable official
whom it will be difficult to replace.

MISCHITLULANHOUS.-

SCR FAUT
Swingey Lecrures on Grotoey.

The lectures for the years 1918-1919 will be given by Professor
T. J. Jehu, M.D., F.R.S.E., at the Royal Society of Arts, John
Street, Adelphia, W.C., on various days during the months of
December, 1918, and January, 1919. The title chosen for the course
is ‘‘ Man and his Ancestry ’’, and the published syllabus of the twelve
lectures promises a comprehensive treatment of this important subject.
Admission to the lectures free.

Pe, isa ie anit se

INDEX.

DIRONDACK Intrusives, 525.
Adirondacks, the Anorthosite
Body in the, 525.

Age of the Bolivian Andes, 838.

Alkali Rocks in the Transvaal, Geology
of, 225.

Alkaline Felspar in Limestone, 135.

Amalitsky, Vladimir Prochorovitch,
Obituary of, 383, 431.

Ammonites, Yorkshire Type, 547.

Ananchytes quadratus, Occurrence ot
the Zone of, 214.

Andesite, Hypersthene, from Pitcullo,
Fifeshire, 346.

Andrews, C. W., A Visit to Christmas
Island, 422; Fossil Mammals from
Salonica and Imbros, 540.

Anorthosites, the Problem of the,
525.

Antarctic Ice-cap, 553.

Arber, HE. A. Newell, Submedullary
Casts of Coal-measure Calamutes,
212 ; Mesozoic Floras of New Zea-
land, 516.

Obituary of, 426.

Artesian Waters of Australia, 177.

Arthropods, Fossil, from Carboni-
ferous, Nova Scotia, 462.
Asterozoa, Paleozoic, 416.
AKER, Herbert Arthur, Pre-

Thanetian Erosion of Chalk,
296, 422; Denudation of the Chalk,
East Anglia, 412.
Balsillie, D., Hypersthene Andesite,
346.
Baltic and Scandinavia, Recent Geo-
logical History of, 354, 397, 451.
Banks Peninsula, Geology of the,
5B} |.

Barberton Gold-mining District, 371.

Bartrum, John A., Queries from New
Zealand, 425.

Basie Intrusions, Radnorshire, 500.

Bather, F. A., Hocystis, 1. Hocystites
primevus, Hartt, 49; Yunnan
Cystidea, 507, 532.

Beasley, H. C., Geological Collection,
528.

Belemnitella mucronata, Thickness of
the Zone of, 350.

Bell, Alfred, Suffolk Boxstones, 15.

DECADE VI.—VOL. V.—NO. XII.

|
)

Bennettitean
taceous, 546. :

Birmingham District, Geology of, 374.

Blattoid and Insect Remains, South
Staffordshire, 374. ‘

Bolton, H., Blattoid and Insect
Remains, South Staffordshire, 374.

Bolton, L. L., Iron-ore in Canada,
377.

Bouchardia (Brachiopoda) and Age of
Seymour Island Beds, 258., :

Boulenger, G. A., Eocene Lizards in
France, 375. ,

Boulton, W.S8., Mammalian Remains,
Stourbridge, 374.

Bournemouth, Geology of the Country
around, 220.

Boswell, Professor P. G. H., British
Supplies of Potash Felspar, 475 ;
British Sands and Rocks used in
Glass-making, 476.

Bowen, N. L., Problem’ of
Anorthosites, 525;
Intrusives, 525.

Boxstones, Suffolk, 15.

Brachiopod genus Liothyrella, of
Thomson, 73.

Brachiopoda, Bouchardia, and Age of
Seymour Island Beds, 258.

British Museum Return, 474.

Bromehead, C. N., Pre-Thanetian
Erosion of the Chalk, 381.

Brown, J. Coggin, Geology and Ore-
deposits, Burma, 372.

Brydone, R. M., Notes on Cretaceous
Polyzoa, 1; New Chalk Polyzoa,
97; ‘Thickness of the Zone of
Belemnitella mucronata, 350.

Buckman, 8. 8., Ammonites of York-
shire Type, 547.

Building and Ornamental Stones of
Canada, 133.

Burwash, EH. M. J., Geology of
Vancouver and Vicinity, 550.

Cones, British Cre-

the
Adirondack

ALCITE Cleavage, 424.
Camsell, Charles, Exploration of
Tazin and Taltson Rivers, 478.
Canadian Fuels, 549.
Carboniferous Arthropods,
Scotia, 462.
Carboniferous Goniatites, British, New
Genus and Species, 434.

36

Nova

562

Carter, William Lower, Obituary of,
382.

Chalk Foraminifera, W. Australia,
83.

Chilton, Charles,
Crustacean, 277.

Christmas Island, a Visit to, 422.

Clays and Boulder-clays, Origin of,
157.

Coal in Spitsbergen, 529.

““Coal-balls’’ near panera, Derby-
shire, 471.

Coal- boring at iBenstiatom, 47.

Coal-fields of Eastern Canada, 31.

Triassic Isopod

Coal - measure Calamites, Sub-
medullary Casts of, 212.

Coal-seams, Splitting of, 477.

Coralline Crag, Stratigraphical

Position of, 409; (Erratum), 480.
Corundum of Zoutpansberg, 549.
Cox, Arthur Hubert, South Stafford-

shire Fireclay, 56.

Cretaceous Faunas, New Zealand, 226
Flora of Russian Sakhalin, 516.
Pelecypoda of Egypt, 37.
Polyzoa, Notes on, 1.
Theropodous Dinosaur, Gorgo-

saurus, 519.
Crustacean ‘Tracks,

Tertiaries, 425.
Cushing, H. P., Adirondack Intru-

sives, 525.

Cystidea, New Genus of, 49.
Yunnan, 507, 532.

New Zealand

ATUM-LINES
Keuper, 121,
Davies, A. Morley, A Note on Isostasy,
125:
Deeley, R. M., Mountain Buiiding,
111, 276.
Denudation, of Chalk, East Anglia,
412.
Derbyshire, Occurrence of
balls ’’ in, 471.
Dewey, Henry, Origin of Land-forms
in Caernarvonshire, 145.
Distribution of British Carboniferous
Goniatites, 434.
Dolomitization and the Leicestershire
Dolomites, 246.
Drawings in Spanish Caves, 173.
‘“Dry’’ Lakes in Western Australia,
Rock-Cliffs and Floors of, 305.
Dry Land in Geology, 333.

in the English

“* Coal-

ARLY Man in America, 518.
Kast Anglia, Stages in the
Denudation of the Chalk in, 412.
Echinoidea and their Allies, 4.

Index.

Economie Geology of the Central
Coal-field of Scotland, 29.

Edinburgh Geological Society, 42, 43,
93, 143, 188, 525.

Elles, Miss, & Wood, Miss (Mrs.
Shakespeare), British Graptolites,
416.

Eminent Living Geologists :
William Lamplugh, 337.

Eocene Lizards in France, 375.

Hocystis, I. Hocystites primevus,
Hartt, 49.

Erosion and Land Forms, Western
Australia, 521.

Pre-Thanetian, of the Chalk in
the London Basin, 296, 381, 422.
Eruptive Phenomena of Italian

Voleanoes, 328.

Etheridge, R., Leaves of Noeggerathi-
opsis, Australia, 290.

Evans, John William, Diagrams
showing Rock Analysis, 422.

George

AULTS in the Californian Coast-
range, 282.

Fermor, L. L., Hollandite, Crystallo-
eraphy of, 376.

Fire-clays and Behaviour on Ignition,
56.

Flathead Coal Area, Geology of, 420.

Flint Implements in Suffolk, 373.

‘*Flint-meal’’ from the British Chalk,
192.

Flora of the Carboniferous of the
Netherlands, 221.

Folkestone Warren, 40.

Foraminiferal and Nullipore Struc-
tures, 203.

Fossil Corals, New, from the Pacific
Coast, 179.

— Kchini of the Panama Canal
Zone, 85.

Insects, Colorado, 40.

Mammals from Salonica and

Imbros, 540.

Man in South Africa, 128.

AILLARD, Cl., Nouveau genre
des Musaraignes, 376.
Geikie, Sir Archibald, Memoir of John
Michell, 517.
James, the
Geologist, 83.
Genetic Classification of Underground
Volatile Agents, 224.

Geological History of the Baltic and
Scandinavia, 354, 397, 451.

—— Society of London, 45, 90, 136,
179, 227, 284, 333, 377.

Man and_- the

Index.

Geological Structure of the Forest of
Dean, 23.

Survey of Great Britain, 473;

Summary of Progress, 28.

of Canada, Department of

Mines Report, 30.

of Scotland, 30.

Geologists’ Association, 46, 144.

Geology of the Moonta and Wallaroo

. Districts, 89.

of North-Eastern Rajputana,

175.

of the South Wales Coalfield,

174.

of Transkei, South Africa, 135.

— of Vancouver, 550.

West Australian, Some Problems

of, 477. ;

Georgia, South, Petrography of, 483.

Glacial Geology of Norfolk and
Suffolk, 331.

Glaciation, Pleistocene, of New Zea-
land, 394.

Glass-making, British Resources of
Sands and Rocks used in, 476.

Gorgosaurus, Cretaceous Theropodous
Dinosaur, 519.

Granular Ivon-ore, Buenos Ayres, 286.

Graptolites, British, 416. ‘

ALL, A. L., Geology of the
Barberton Gold-mining District,
Byfale

Hall, Richard, 336.

Harmer, F. W., Glacial Geology of
Norfolk and Suffolk, 331; Pliocene
Mollusea, 416; The Stratigraphical
Position of the Coralline Crag, 409.

Haughton, S. H., Fossil Man in South
Africa, 128.

Hawkins, Herbert L., Echinoidea and
their Allies, 4, 489; Occurrence
of the zone of A. quadratus,
214,

Heterosorex delphinus, Gaillard, anew
Insectivore, 376.

Hewitt, W., Pebbles in their Geologi-
cal Association, 557.

Hind, Wheelton, British Carboni-
ferous Goniatites, 434; Productus
humerosus, 480. -

Hinde, George Jennings, Obituary of,
145,233:

Holectypoida Echinoidea, 489.

Hollandite, Crystallography,
Nomenclature, 376.

Homalonotus, Notes on the genus,
263, 314.

Homocline and Monocline, 227.

Homeceomorphy, 39.

and

563

Horses, Fossil, America; 518.

Howorth, Sir Henry H., Geological
History of the Baltic and Scandi-
navia, 354, 397, 451.

Hrdli¢ka, Ales, Early Manin America,
518.

Hurunui Valley, Structure and Glacial
Features, 523.

Hyena-den in Ireland, 127.

Hypersthene Andesite from Pitcullo,
Fifeshire, 346.

CEH Age and Antarctic Research,
129.

Imperial Institute Map of Metals in
British Empire, 543.

Mineral Resources Bureau, 434.

Insects, Fossil, in Coal-measures, 520.

Tron, the Outlook for, 332.

Iron-fields of Lorraine, 481.

Iron-ore, Occurrences in Canada, 176,
377.

Isopod Crustacean, Triassic, Australia,
277.

Isostasy, a Note on, 125, 192, 233.

ACKSON, Wilfred, New Brachiopod
Genus, 73; Terebratula Grayi,
479.
Jeffreys, Harold, Causes of Mountain-
building, 215, 380.
Jehu, Professor T. J., Rock-boring
Organisms in Coast Erosion, 520.
Johns, Lieut. Graham, Obituary of,
S2Ke

Johnston, Robert Mackenzie, Obituary
of, 288.

Johnston-Lavis, H. J.
Italian Voleanoes, 328.

Jutson, J. T., Rock-Cliffs and Floors
of ‘‘Dry’’ Lakes, W. Australia,
305; Erosion and Land Forms,
W. Australia, 521; Formation of
“Natural Quarries’’, W. Australia,
521.

(the late),

ALGOORLIE, Geological Fea-
tures of the *‘ North End ’’, 225.
Kaolin Veins, 79.
Kendall, P. F., Splitting of Coal-
seams, 477.
Keuper, Datum-lines in English, 121.
Kidston, R., and Jongmans, W. J.,
Flora of the Carboniferous of the
Netherlands, 221.
King, W. Wickham, Downtonian of
S. Staffs, 374.
Klondike District, Frozen Muckin, 479.
Knipe, Henry Robert, Obittiary of, 432.

564

Kryshtofovich, A., Cretaceous Flora
of Russian Sakhalin, 516.
Kyson Monkey, the, 48.

AMBE, Lawrence L., The Cre-

L taceous Theropodous Dinosaur
Gorgosaurus, 519.

Lamplugh, George William, Eminent
Living Geologist, 337.

Land-forms in Caernarvonshire, Origin
of, 145.

Laterite in Western Australia, 385.

Leaves of Noeggerathtopsis, Australia,
290.

Lebour, George Alexander Louis,
Obituary of, 287.

Leicestershire Dolomites and Dolo-
mitization, 246.

Lewis, W. J., Downtonian of S. Staffs,
374. 5

Lias of South Lincolnshire, 64, 101.

Limestones of South Africa, 522.

Lincolnshire, Lias of, 64, 101.

Inothyrella of Thomson,
Brachiopod Genus, 73.

Liverpool Geological Society, 231, 526.

Lorraine, Iron-fields of, 481.

Ludlow Museum, 336.

New

ACKENZIEH, J. D., Geology of
the Flathead Coal Area, 420.
Maitland, A. Gibb, Problems of West
Australian Geology, 477.
Mammalian Remains, Glacial Gravels,
Stourbridge, 374.
Manson, Marsden, Ice Age and Ant-
arctic Research, 129.
Mesozoic Floras of Queensland, 516.
of New Zealand, 516.
Metals, Chief Sources of British
Empire, 543.
Metamorphism and its Phases, 223.
Michell, John, and Martin Simpson,
Pioneer Geologists, 131.
Memoir of, 517.
Mineral Industries of United States,
281.
Production of Canada, Report,
Ottawa, 30.
Resources of the British Empire,

82.

of Great Britain, 418.

Bureau, Imperial, 433.

Mineralogical Society, 44, 94, 230,
380.

Mineralogy of Black Lake Area,
Quebec, 549.

Minerals associated with Crystalline
Limestone, California, 35.

of Glamorgan, 40.

Index.

Minerals used in the Arts and In-
dustries, Corundum, 373. :

—. Graphite and Asbestos,
420-1. §

—— Maenesite, 548.

Mining Operations of South Australia,
33,178.

of Thin Coal-seams, Canada,

32.

Mitchinson, the Rt. Rey. Bishop John, |
Obituary of, 527.

Moir, J. Reid, Flint Implements in
Suffolk, 373.

Monazite Sand Deposits of Travancore,
Report, 38.

Morphological Studies of the Hehi-
noidea, 4, 489.

Mountain-building, 111, 276, 380.

Causes of, 215.

Moysey, Captain Lewis, Obituary of,
189.

Musaraignes, Nouveau genres des,
376.

} EW Zealand, Igneous Rocks of,
552.

Newton, E. T., Exploration of Irish
Caves, 127.

Newton, R. Bullen, Foraminiferal and
Nullipore Structures, 203.

Jubilee of, 96.

Noeggerathiopsis, Leaves of, Australia,
290.

Norite of the Sierra Leone, 21.

Notes on new or imperfectly known
Chalk Polyzoa, 97.

AMARU, the Volcanic Rocks of,
552.
Obituary Notices: Amalitsky, Vladimir

Prochorovitch, 3884, 431; -Arber,
E. A. Newell, 426; Carter,
William Lower, 382; Hinde,

George Jennings, 146, 233; Johns,
Lieut.. Graham, 527.; Johnston,
Robert Mackenzie, 288; Knipe,
Henry Robert, 432; Lebour, Pro-
fessor George Alexander Louis, 287;
Mitchinson, The Rt. Rev. Bishop
John, 527 ; Moysey, Captain Lewis,
189; Parker, William Albert, 95 ;.
Seymour, Maude, 560; Watson,
John, 383; Williams, Henry
Shaler, 528; Williston, S. W., 559.

Ordovician and Silurian Fossils from
Yunnan, 330.

Ore Deposits near Oda, Japan, 36.

of Bawdwin Mines, Burma, 372.

Origin of Clays and Boulder-clays,
Malay States, 157.

Index.

Origin of some Land-forms in Caer-
narvonshire, 145.

Osborn, Henry Fairfield, American
Fossil Horses, 518.

Ossiferous Caves, Torquay, 548.

Outlier in Valley of Rakaia, New
Zealand, 551.

ALA ONTOGRAPHICAL Society,
416.
Park, Professor James, Pleistocene
Glaciation of New Zealand, 394.
Parker, William A., Obituary of, 95.
Parsons, L. M., Dolomitization and
the Leicestershire Dolomites, 246;
Productus hwmerosus, 559.

Patagonian Geology, 376.

Pebbles in their Geological Associa-
tion, 5.

Pecten-like Shell-fragments, 168.

Pelecypod Shell-fragments (described
as Cirripedes), 168.

Permian of the Midlands, 232.

Petrography of the Pacific Islands,
281.

of South Georgia, 483.

Phosphates of Saldanha Bay, 133.

Phylogeny and _ Classification of
Reptiles, 374.

Physiographic Significance of Laterite
in W. Australia, 385.

Pigeon Point, Minnesota, 282.

Pleistocene Glaciation of New Zealand,
394.

Pliocene Mollusca, 416.

Polyzoa, Cretaceous, Notes on, 1.

New Chalk, 97.

Potash Felspar, British Supplies of,
475.

Pre-Thanetian Erosion of Chalk in
the London Basin, 296.

Productus humerosus, Canuvia-
Seminula Horizon of, 480.

eared coc of Canadian

\ Mineral Springs, 222.

Radnorshire, Basic Intrusions, 500.

Rastall, R. H., The Genesis of the
Tungsten Ores, 194, 241, 293, 367;
Tron-fields of Lorraine, 481, 543.

Reed, F. R. Cowper, Notes on the
genus Homalonotus, 263, 314;
Fossils from Yun-nan, 330.

Report of Mines Branch, Department
of Mines, Canada, 371.

Reports on Mineral Resources of Great
Britain, 377.

Ripple-marks, Recent and Fossil, 33.

Rock Analyses, Diagrams of, 422.

565

Rock-boring Organisms, Agents in
Coast Erosion, 520.

Rock-Cliffs and Floors of ‘‘Dry”’’
Lakes in W. Australia, 305.

Royal Society of London, 41, 283.

Ruitor Glacier Lakes, 551.

ALONICA, Fossil Mammals from,
540.

Salts as Agents of Rock Weathering,
W. Australia, 521.

Sands used in Manufactures, 131.

Scharff, R. F., Exploration of Irish
Caves, 127.

Serivenor, J. B., The Kaolin Veins,
79; Origin of Clays and Boulder-
clays, 157.

Seymour, H. J., Exploration of Irish
Caves, 127.

Seymour, M., Obituary of, 560.

Shand, Professor 8S. H., The Norite of
the Sierra Leone, 21.

Sherlock, R. L., Datum - lines in
English Keuper, 121.

& Smith, Reports on Mineral
Resources of Great Britain, 377.
Sibly, T. Franklin, Geological Structure

of the Forest of Dean, 23.

Sierra Leone, the Norite of the, 21.

Simpson, Martin, a Yorkshire
Geologist, 82.

Swocystis, Species of, 532.

Smith, H. G., Basie Intrusions,
Radnorshire, 500.
Societies and Museums, Work of

Local, 474.

South Staffordshire Fire-clays, 56.

Speight, R., Geology of Banks
Peninsula, 523; Structural and
Glacial Features of the Hurunui
Valley, 523.

Spencer, W. K., Palzeozoie Asterozoa,
416.

Spitsbergen Coal, 529.

Stopes, M. C., Bennettitean Cones,
546.

Stratigraphical Position of the Coral-
line Crag, 409.

Submedullary Casts of Coal-measure
Calamites, 212.

Subsidence Theory of Coral Reefs, a
New Test of, 178.

Suffolk Boxstones, 15.

Swiney Lectures, 560.

AZIN and Taltson Rivers, N.W.
Territories, 478.
Terebratula Grayi, Davidson, 479.
Tertiary Beds of Castle Hill or Tre-
lissick Basin, New Zealand, 551.

566

Tertiary Foraminiferal and Nullipore
Structures, 203.
Thomson, J. Allen, Bowchardia and
Age of Seymour Island Beds, 258.
Tillyard, R. J., Fossil Insects in
Coal-measures, 520.

Tin-fields, North Queensland, 34.

Toit, A. L. du, Zones of the Karroo
System, 421.

Travancore, Geological Annual Re-
port, 39.

Triassic Isopod Crustacean, Australia,
277.

Tritylodon, 40.

Trueman, A. H., Lias of South
Lincolnshire, 64, 101.

Tungsten Ores, the Genesis of, 194,
241, 293, 367.

Tyrrell, G. W., Petrography of South
Georgia, 483.

Tyrrell, J. B., Frozen Muck in
Klondike District, 479.

NIVERSITY College of Wales,
Aberystwyth, 96.

ANCOUVER and Vicinity, the
Geology of, 550.
Varney, W. D., Occurrence of Coal-
balls, 471.
Varro on Soils, 39.
Veins of Kaolin, 79.
Voleanic Studies in Many Lands, 86.
Volcanoes, Active, of New Zealand,
Q2ile

AGNER, P. A., Minerals used in
the Arts and Industries, 373,
420, 421, 548.
Waikonaiti Sandstones, Otago, 553.

Index.

Walkom, A. B., Mesozoic Floras of

Queensland, 516.

Watson, John, Obituary of, 383.

Wealden and Purbeck Fishes, 416.

White, H. J. Osborne, Geology of

- Country around Bournemouth, 220.

Wilcockson, W. H., Coal in Spits-
bergen, 529.

Williams, Henry Shaler, Obituary of,
528.

Williston, 8. W., Phylogeny and
Classification of Reptiles, 374;
Obituary of, 559.

Windhausen, A. , Patagonian Geology,
376.

Withers, Thomas H., Pelecypod
Shell-fragments described as Cirri-
pedes, 168.

Woodward, Dr. A. S., Wealden and
Purbeck Fishes, 416.

Woodward, Henry, Carboniferous
Arthropods, Nova Scotia, 462.

Woolnough, W. G., Laterite in
Western Australia, 385.

Worm-borings in Rocks, 46.

ye Cystidea, 507, 532.

INC-ORES, Imperial Institute
Monograph, 522.
Zone of Ananchytes quadratus in
Berks, 214.

of Belemnitella mucronata,

350.

Zones of the Karroo System and their
Distribution, 421.

Zoological Society of London, 285.

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