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THE
GEOLOGICAL MAGAZINE,
DECADE VI. VOL. IV.
JANUARY—DECEMBER, 1917.
sy)
THE
GEOLOGICAL MAGAZINE
Monthly Journal of Geology.
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NOS. DCXXXI TO DCXLII.
EDITED BY
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ASSISTED BY
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Dr. GEORGE J. HINDH, F.R.S., F.G.S.
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Prorrssor J. E. MARR, M.A., Sc.D. (Camb.), F.R.S., F.G.S.
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Prorrssorn W. W. WATTS, Sc.D., LL.D., M.Sc., F.R.S., F.G.S.
Dre. ARTHUR SMITH WOODWARD, LL.D., F.R.S., F.L.S.,
WAESGES)
DHCADEH VI“
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JANUARY—DECEMBER, 1917
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OGD
XXV.
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XXVII.
XXVIHI.
OXI"
LOGE
XGROII:
SOON Ie
NOXOMLY
KR:
ES Om EATS:
Rock-sections, Cil-y-Coed
Chalk Polyzoa i :
Maitai Lamellibranch and Corals
Maitai Brachiopods, Gasteropods, etc.
View of apa ee Iceland. Fallen Block « of Liparite,
Jafnadal : :
Phycomycites nee ation etc.
Lateral Attachment of Rugose Corals
Chalk Polyzoa ‘
Integument of Wealden Dinosaurs
Picrite from Mozambique 5
Portrait of Dr. Henry Fairfield akon ;
Surface Features of Discoides and Conulus
Poikilosakos petaloides .
Portrait of the late Charles Soe Beer Assoc. R. 8. M.,
F.G.S. : : F
Systems of Holectypus aa ae Cen
Hapsidopora and Tylopora
Portrait of Alfred Harker, M.A.,LU.D., F.R.S., Pres. Geol. Soc.
Gasteropoda, New Zealand
Cretaceous Fossils, New Zealand
Dyplodocus Carnegier 5
ae 34 (restoration) .
Pycnodus platessus : : ‘
Perignathic Girdle of Discoides cylindricus
Map of Charnian Movement, E. Kent
Perignathice Girdle of Conulus albogalerus
Rock-sections, Pahang Voleanic Series .
Geological Sketch-map of part of Ulu Pahang, F. MM. States
Portrait of the late Alfred N. Leeds
Chalk Polyzoa
Sketch-map of Ambrym Tiana. Nee Hebrides
Fossil Shark showing spiral Coprolite
Prof. H. Hull, M.A., LL.D., F.R.S.
FACING PAGE
a. Als)
20
53
63
64
97
102
115
145
150
157
193
205
219
242
255
258
289
305
305
342
307
359
389
397
399
401
441
462
503
478
496
529
542
553
LIST OF ILLUSTRATIONS IN THE TEXT.
PAGE
Map of Hgyptian Oilfield Region . : : ‘
Diagrammatic section across Egyptian Oilfield ‘ : : 5 : 8
Geological sketch-map of N.W. Carnarvonshire . : : i By) kB}
Geological map of part of S.W. Carnarvonshire . : P : Boy LU)
Sketch-map of Lodmundarfjord District 5 : » Os
Animal remains in Dunliath Ferruginous Limestone, N. W. Sjootiead . 103
Two polyparia of solitary Rugosa ‘ : . 110
Diagram arrangement of outcrops of septa on Bee of polvpabiurn 5) dlatil
Diagram of calice of Hadrophyllum pauciradiatum . é i . 113
Sections of Lophophyllum proliferum . : . 114
Symbols of sub-rangs and rangs (classification of loveone Oe) oy tal)
Diagram of disturbed gravels : : . 159
Diagram summarizing views of Wachsmuth & Sareuen< on cninotd pane . 206
Schematic figure of ventral valve of Poikilosakos petaloides 9 . 214
Dithyrocaris tricornis and D. testudinea, Scouler 3 ; : Bn ear(al
Sketch-map and section along railway, Arkleston, Paisley . ! . 274
Rock-section of Cumbraite . : . : ; : ; : . 307
Peristomial structures of Plesiechinus ornatus . 344
Schematic restoration of attachment of lantern fwslee in Diesen . 347
Rock-sections, Tholeiite ; : j 9 ; f i 4 5 BislL
Rock-section, Olivine-tholeiite : : A : : . f 5 oe)
Ribs of Diplodocus in position . 4 : . 360
Posterior aspect of pelvis and hind- a of Dubladecus ‘ 2 . 3861
Hind-limb of Diplodocus : 5 A ; : : 5 . 362
Two views left femur of Deniodgeus : ; ; : : 6 . 362
Fore-limb and humerus of Diplodocus A : 368
Diagram showing wrong articulation of limb Benes and Wouking af
humerus of Diplodocus (ground-plan) . 5 s aa 2) OD)
Mesodon macropterus (Agassiz) . : : ‘ : : : . 3886
Geological section at the Front : ; : : : : : . 432
Polymorphites, last and adult sutures . : : : : ; . 443
Development of Polymorphites jupiter . ; : : : : . 444
Sutural development of P. jupiter ‘ ; ; : : i . 445
Sutural development of Cymbites globosus . : : j Pane Te Ah
Sketch-map of Folly Farm, Presteign . ‘ : ; . 482
Vertical section of upper part of borehole, Folly Harn ; 491
Restored skeleton of Ichthyosaurus, Lower Lias, pee Regis, with ‘pina
coprolite (a) beneath (after Owen) . : : j : . 541
Composition of sub-Cretaceous surface of Hast Kens ‘ ‘ : . 544
Isopachyte System, Wealden, East Kent : : ; ; : . 547
Section across Hast Kent from Deal to Ellinge : : i : . 548
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ORIGINAL ARTVICLILES-.
Q.J.G.S., vol. xxxv, p. 296, 1879.
§ Op. cit., p. 298.
7 GEOL. MaG., Vol. IX, p. 552, 1882.
8 Bala Volcanic Series of Carnarvonshire, 1888, pp. 44-5.
Part of Carnarvonshire. iy
drift-covered, and in consequence well cultivated. As a result
only three rock-exposures occur in this area—Cil-y-Coed, Craig-y-
Dinas, and Caer Engan. Cil-y-Coed and Caer Engan are two small
hills, whilst Craig-y-Dinas, with Pentwr to one side of it and Bryn-
mawr to the other, are on the slopes of rising ground. It will be
convenient to consider each of these exposures separately, commencing
with Cil-y-Coed, which is the largest and also the most south-westerly
of the three.
1. Crt-y-Corp. (See Map II.)
A. Surrace Fratures.—This hill, situated about three-quarters of
a mile from the village of Clynnog Fawr on the north-west coast of
Carnarvonshire, attains an elevation of about 480 feet O.D., and
stands out prominently from the drift plain which stretches for 6 or
7 miles along Carnarvon Bay. It is the first hill of a series
increasing progressively in height towards the south, and it covers .
an area of nearly a quarter of a square mile, being about 1,000 yards
long and 900 yards wide at its broadest part. The northern slopes
of the hill are everywhere gentle, except at the extreme north-
west, where crags are exposed, making the slope somewhat steeper.
On the south-west and west sides, however, the ground drops very
abruptly from 480 to 200 feet, below which level there is a gentle
slope down into the plain. On the north side the rocks are smoothed
by glaciation, and the lower flanks of the hill on every side are
eovered with a thin deposit of drift. The contour of the hill was
undoubtedly carved out by the Irish Sea ice-sheet, which traversed
the hill from the north. There is also a small capping of drift on
the, actual summit near the south-west extremity.
B. Pere-Camprian, THE Rayouric Serres.—The hill in part
undoubtedly owes its prominence to an igneous rock which is
exposed more or less continuously in a line of crags on the west side
- extending from the roadway to the top of the hill, a distance of about
650 yards.
(i) Stratigraphy (see Map I1).—It will be convenient to begin our
description with the most northerly rocks exposed. These are to be
seen on the north-west side of the hill, 20 yards away from the small
quarry that is situated here. In hand specimens the rock appears to
be a dark felsite, noticeable for the presence of numerous porphyritic
erystals of quartz and of pink felspar. The groundmass is fine-
grained and compact, hence the rock is very hard and tough.
The next exposure examined is in the quarry itself, where the rocks
appear in hand specimens to be rather different from those just
described. Although still felsitic-looking the rocks here are light-
coloured, and only on close examination are any porphyritic crystals
to be seen. In the mass the rock appears to be a rhyolite, and it is
probably to the rock exposed in this quarry that Tawney and Harker
refer. The rocks are much jointed and sheared, and readily break
into angular chips. The main joints strike E. 10° N. and dip
N. 10° W. at an angle varying from 60° to 80°. Other joints strike
1 The area here dealt with is shown on Map II in dotted lines.
DECADE VI.—VOL. IV.—NO. I. 2
18 LE. Wynne Hughes—Geology of
N. 40° E. and dip N. 50° W. at an angle of 60°, being thus roughly
at right angles to the major joints.
In traver sing the hill in a south-easterly direction from the quarry
several rock exposures are met with. A few yards away from the
quarry a dark rock, containing porphyritic crystals of quartz and
pink felspar, is seen once more. It is in every respect macro-
scopically similar to the dark felsitic rock mentioned above. We thus
have a band of pale felsitic rock (which we may term the pale
variety) lying between two dark felsitic bands (which we may term
the dark variety). The more southerly band is about 40 feet wide.
Following is a narrow band of the pale variety. Succeeding this
a dark felsitic rock again occurs as a band about 20 feet wide.
Macroscopically it only differs from the dark bands in that the pink
felspars are distinctly smaller. This band is succeeded by another of
the pale variety—15 feet thick—and in turn by a massive dark band,
macroscopically very similar.
Proceeding eastwards from this point, there is no exposure for
fully 100 yards until another small quarry is reached. From here
on to the most easterly part of the hill, igneous rock is exposed at
several places, but in all cases it consists of the pale variety,
macroscopically similar to bands already noticed in the first quarry.
Along the south-west flanks of the hill a similar alternation of the
pale and dark rocks is evident. These bands, however, are not
persistent. For instance, the thin band does not occur on this side,
so that two bands have here coalesced, giving a massive band of the
dark variety having a width of fully 100 feet, Further south occurs
also a tongue of the dark variety wedging into the pale variety.
The line of strike given by this rough banding of the two varieties
of rock is N. 60° H.
(ii) Microscopie Description.—On examining thin sections of the
rock from the various exposures there is found to be a surprising
resemblance between the pale and the dark varieties.
(a) Phenocrysts.—In both cases porphyritic quartz and felspar
crystals are prominent, the quartz being the more abundant. The
quartz sometimes show good crystal forms, but more often are
corroded and rounded (Pl. I, Figs. 1, 2), and frequently the matrix
may be seen in cracks in the crystals (Pl. I, Figs. 1 and 5).
Most of the porphyritic crystals of felspar are plagioclases with
multiple twinning (Pl. I, Fig. 5), but in nearly all cases simply
twinned or untwinned crystals of orthoclase are also present (Pl. I
Fig. 1). The plagioclases appear to approximate to albite, and
erystals of chequer albite’ are occasionally present. This chequer
albite is sometimes intergrown in perthitic fashion with untwinned
felspar. Phenocrysts of biotite are also sparingly distributed
throughout the rock. Muscovite, evidently of secondary origin, is
always present.
(6) Groundmass.—These various phenocrysts are embedded in
a felsitic groundmass. This again shows a general similarity in both
the pale and the dark varieties, although a certain amount of
1 J.S. Flett, Mem. Geol. Surv. (Newton Abbot), 1913, p. 60.
eS
‘mon. MaG., 1917. Prarr I
ROCK-SECTIONS, CIL-Y-COED.
». '
Part of Carnarvonshire. 19
variation is usually to be seen even in a single rock section. The
matrix is typically cryptocrystalline, but occasionally becomes
microcrystalline in character. Microspherulitic textures are of
frequent. occurrence, and on the whole this is more commonly the
case in the dark variety.
In many cases the manner in which the various types of matrix
are intermingled one with another and drawn out in streaky fashion
shows that we are dealing with rhyolites having a well-defined flow-
structure. This structure is sometimes developed on a very small
seale (Pl. I, Figs. 1, 3). In other cases, however, the original
character of the rock is by no means so clear, since in these the
matrix with its different types of recrystallization presents a patchy
rather than a streaky texture, suggesting at first sight a tuff. The
streaky appearance, however, still persists to a certain extent, and in
such cases the patches frequently end off rather abruptly along the
direction of the flow-structure. It is extremely difficult to determine
whether such rocks are lavas with flow brecciation or rhyolitic tufts
containing rhyolitic lapilh.
The presence of the very numerous and large felspar i oeneees
and still more so of the quartz phenocrysts immediately suggests
that the rocks belong to a series of Pre-Cambrian age, since these
characters appear to be of universal occurrence in the “Page Cambrian
rhyolites of Wales, whereas they are not found in the Ordovician
rhyolites. In this connexion it is also noteworthy that the micro-
spherulitic texture described above appears to be of frequent
occurrence in the Pre-Cambrian rhyolites of North Wales, whereas
it is not found to any extent in rhyolites of Ordovician age in North
Wales.
C. CamBrian Snonuient ce Serius. (1) Conglomerate. (a) Strati-
graphy.— Beyond the rhyolite we come to the crags which form the
highest ridge on the hill at its south-west end. These crags are due
to the presence of a hard conglomerate, the nature of which is well
shown on the weathered surfaces. The well-rounded pebbles in this
conglomerate vary considerably in size; whilst the majority are from
1 to 2 inches in diameter, others may attain a diameter of 12 inches.
These pebbles are embedded in a fine gritty matrix. All the pebbles
consist of felsites with porphyritic crystals of quartz and felspar, and
_ they closely resemble the rocks of the rhyolitic series already
described. In fact, near the line of junction of the conglomerate and
the rhyolitic auc. where the pebbles of the conglomerate have been
pressed into the rhyolitic rock, the resemblance between the two is
so close that it is only on careful examination that the outline of the
pebbles can be seen.
This conglomerate strikes N. 80° E. When followed across the
strike in a south-westerly direction the conglomerate passes into
a grit which is, however, still occasionally pebbly. This conglomerate
band continues until it is buried in the drift on the south-west slopes
of the hill.
Proceeding along the strike in the opposite direction—north-east—
the pebbles decrease rapidly in size in the course of a few yards, but
the matrix retains its original character. In a newly opened quarry
20 EL. Wynne Hughes—Geology of
at the north-east end of the hill, quite a number of pebbles of
rhyolite, some 3 to 4inches long, are seen, but the majority of the
pebbles are small and well rounded. It is only in this exposure
that we get any indication of stratification in the conglomerate.
Generally the dip of the rock is quite obscure, as is often the case in
massive conglomerates; but in the freshly cut rock in this quarry
alternate layers of pebbles and fine grit are distinctly visible. The
lie of the pebbles suggests a dip of about 50° to S.K. In the quarry
the rock is seen to be jointed, some joints sloping in the direction of
the dip of the pebbles, crossed by others at right angles.
(2) Microscopic Examination.—Several thin sections were prepared
from specimens collected from different places along the outcrop,
both from the highly pebbly conglomeratic portion and from the less
pebbly and more gritty portion. Every slide confirms the con-
glomeratic nature of the rock. They show the presence of felspar,
quartz, and numerous chips of rhyolite and fragments of tuff
(Pl. I, Fig.6; PLII, Fig. 1). The felspars usually exhibit multiple
twinning, but are mostly decomposed. The quartz almost
invariably show subangular edges. The matrix is felspathic and
fine-grained, often containing small crystals of muscovite.
Sections of some of the larger pebbles were also examined, and
these compare in every respect with the rhyolitic rocks described
above (p. 19). They contain crystals of felspar and quartz embedded
in a felsitic groundmass, which in some cases shows a characteristic
flow-structure.
At right angles to the strike—in a south-east direction—the
conglomerate rapidly changes to a grit, the width of a distinctive
conglomerate being about 18 feet.
(ii) The Grit Band. —(a) This band of grit is about 12 feet thick,
and extends from the south-west to the north-east end of the hill.
Under the microscope the grit is seen to contain angular and sub-
angular crystals of quartz. in large number, along with numerous
felspar crystals (partly kaolinized) ; and occasional chips of rhyolite
also oceur (PI. II, Fig. 1).
(6) This fine erit, “when followed southwards across the strike,
gives place to a distinctly coarser rock which is very much weathered.
When followed along the strike to the south-west this rock becomes
still coarser and still more weathered. A microscopic examination
shows the rock to be largely composed of angular quartz erystals—
often sheared—set in a felspathic cement (Pl. II, Fig. 5).
Both these bands of grit, fine and coarse, persist in a north-
easterly direction for a distance of 900 yards, with but a slight break
where the hill is capped with drift. At the north-east end of the
hill there is the same succession of conglomerate, fine grit and coarse ~
grit, precisely as one would expect to find them on the supposition
that the dip 1 is, as stated above, S. 30° E.
There is a decided dip in the ground beyond the outcrop of the
quartz grit, and no further exposure is visible, all the land on the
south-east side of the grit being under cultivation. This is most
unfortunate, as it is impossible without further exposures on that
side to determine the exact relation of the grits to the other
formations of the district.
12 wes, IDL.
ROCK-SECTIONS, CIL-Y-COED; anp 4 anp 6 BWLCH-Y-LLYN.
.
Part of Carnarvonshire. | 21
D. Sommary oF tHe Succession.— We have then at Cil-y-Coed the
following descending sequence :— :
(i) A quartz grit 6 or more feet thick.
(ii) A fine felspathic grit 8 feet thick.
(iii) A conglomerate 18 feet thick.
All with a strike N. 60° E. and a dip of 50° to S. 30° E. These
rocks rest on
(iv) A volcanic series consisting of rhyolitic lavas and tuffs which
appear to dip 60-80° N. 10° W.
The pebbles in the conglomerate are undoubtedly derived from the
underlying rhyolitic series.
This apparent discordance of dip suggests the presence of an
unconformity between the sedimentary rocks and the volcanic series
of rocks. ‘The exposures, however, are not sufficient to actually
prove the existence of this unconformity, and it would require
considerable trenching to make it apparent.
EK. Retarron to tae Surrounpine ABeEas.—On attempting to
trace the beds into surrounding areas we find that Cil-y-Coed is
somewhat isolated.
(i) North and West Side.—On the north and west side the mass
is flanked by glacial drift, which stretches as ‘a continuous sheet
right to the seashore, 500 yards distant.
Gi) South-Hast and East Side.—On the south-east and east side
the ground is under cultivation, and no semblance of solid rock is
to be seen except in a field near Garregboeth, distant 30 yards from
the nearest exposure of the grits. Here an arenaceous slate is seen,
but it is doubtful whether this rock is really in situ. Assuming that
it really is in place, then it undoubtedly forms a continuation of
a considerable mass of arenaceous slate which is exposed at Pen-y-
garree some yards further on. Between these two exposures there
is an intrusive mass of picrite.
This band of arenaceous slate gives rise to a prominent feature at
Pen-y-garreg, and it can be traced for at least two miles to the
south-west, the outcrop generally running in a north-east to south-
west direction.
In the Survey memoir this arenaceous slate is considered to be of
Silurian (Ordovician) age, but no fossils have as yet been found in
the neighbourhood. The slate is very different from the blue and
purple slates of the Cambrian Series, which are so persistent in the
Nantlle Valley and were traced by the Survey as far as Llwyd-Coed,
three miles north-east of Cil-y-Coed. The Survey assume the
existence of a fault im this neighbourhood throwing down the
Silurian beds against Cambrian rocks. The memoir states :—
“* South of Llanilyfni the strike of the Cambrian rocks changes to east and
west, and the purple slate does not occur south or south-west of Mynydd
Llanllyfni and Ty Coch near Clynnog Fawr. The drift-covered district further
south is composed of black and ferruginous Silurian shales and grey sand-
stones. The point farthest south where purple slate has been found is at
Llwyd-Coed about a mile south of Llanllyfni, and to the west of the last-named
place the ground is so obscure that the reason for the disappearance of the
slate is unknown. The fault which throws the (Cambrian) slate against the
quartz porphyry ridge (St. Annes—Llanllyfni ridge) is probably continued along
22 E. Wynne Hughes—Geology of
the boundary of the trap as far as Llanllyfni, and west of that village perhaps
throws the slate down against the low Cambrian grits and conglomerates that
form the western boundary of the porphyry.’’*
If we accept these slates on the south-east side of Cil-y-Coed as
Ordovician, as the Survey imply, the only inference that can be
drawn is that the Cil-y-Coed Series is of earlier date than Lower
Ordovician.
(iii) South-West Side.—On the south-west side the rock surface
slopes steeply until cultivated land is reached. ‘This is the case all
along this side exvept at the extreme end of the mass. Here the
rock disappears in a wooded glen, and although the glen is narrow
and deep, with a brook running down its entire length, no exposure
is seen anywhere in the glen; but the debris in the bed of the brook
suggests the proximity of the rhyolitic series. On the south side of
this brook and 30 yards from it is an old ‘‘trial”’ level. This adit
cuts into slate. The slate is black and is irregularly cleaved, the
cleavage striking E. 10° N. and dipping 80° S. 10° E. In this adit
there are about five hard black bands varying from 1% inches to
2 feet in thickness and dipping in the same direction as the cleavage,
but at a slightly smaller angle. The black bands are not cleaved,
but are somewhat stratified parallel to their edges. They undoubtedly
mark the true dip of the beds, which is therefere about 60° to the
south. The slate in the adit is undoubtedly identical with the black
. ferruginous slate of the Ordovician system. It is in the direct line
of strike of the grits on Cil-y-Coed.
The difference in the dip, but the much greater difference in the
nature of the exposures on each side of the brook, coupled with the
narrow glen separating the two, suggests the presence of a fault at
this point. The map accompanying the Survey memoir shows a fault
between the Cambrian and the Silurian Series curving round to the
west at a point about 100 yards to the north-east of Cil-y-Coed.
This fault has already been referred to (p. 21) in the extract from
the Geological Survey memoir. A continuation of this fault in its
south-westerly direction for another 1,200 yards, before turning to
the west, would bring it down the glen separating the Cambrian and
Pre-Cambrian rocks from these Ordovician slates in the quarry.
Such a prolongation of the fault is shown in Maps I and II.
(iv) Worth-Hast Side.—Following the strike of the Cil-y-Coed
rocks in a north-easterly direction we come again to cultivated land,
where no rock exposure is visible. A careful search in all the fields
on this side of the hill discloses no rock exposures. The River
Desach cuts its way through a gap on this side, but even here no
rock exposures are found. A little way on, however, at Pentwr,
half a mile from the most easterly exposure on Cil-y-Coed, a small
quarry was opened in 1912 for building-stone. The rock here
exposed is a bluish fine-grained grit, approximating almost to a hard
shale. At the south-west end of the quarry is green slate, but no
indication of the dip is disclosed in this exposure. Further to the
east, 60 to 70 yards away, there is again an exposure of green slate;
the weathered surface shows the cleavage to strike E.N.K.—W.S.W.,
1 Mem. Geol. Surv., 1866, p. 143.
Part of Carnarvonshire. 23
but the dip of the beds is not clear in such a small exposure.
Continuing from here in a N.N.E. direction we come to a much
larger exposure of rocks at Craig-y-Dinas, separated from Pentwr by
three small exposures of purple slate. The several exposures in this
neighbourhood will now be described in greater detail.
2. Penrwr, Cratc-y-Dinas, anp Bryn-Mawe.
These three places are on the slopes of a ridge which stretches
practically from Glynllifon to Cil-y-Coed. The crest of this ridge
along almost its whole length attains an altitude of 200 feet. At
Craig-y-Dinas the River Llyfnwy cuts through the ridge in a
roughly semicircular sweep exposing precipitous rocks at several
localities on both banks of the river.
A. Camprran, Sepimentary Rocks. (1) Conglomerate.—This rock
is best exposed on the right bank of the river at the end of the gap
farthest from the sea. The pebbles in this conglomerate are com-
parable in size with those at the north-east end of the exposures at
Cil-y-Coed, being seldom more than an inch in length. They consist
essentially of rhyolitic and felsitic chips. In addition occasional
chips of a slaty nature occur, and in this respect the rock differs
from the Cil-y-Coed conglomerate. The matrix of the conglomerate
is felspathic, and approximates both in hand specimens and under
the microscope to that already described at Cil-y-Coed. The rock is
considerably sheared, and the pebbles have arranged themselves in
the direction of shear, which dips generally at an angle of 70° S8.S.E.
The true dip of the conglomerate is obscured by cleavage.
(ii) G@rit.—Overlooking the conglomerate, to the south-east of it,
is a coarse grit in which there are several bands of a much finer grit.
Some of these bands, though only 1 inch thick, are very persistent.
In one locality the river runs for 100 yards in a N.K.-S. W. direction.
Here the bands are perfectly horizontal, suggesting that the strike of
the rock is approximately in the same line. Further down the river
runs east and west, and here the dip of the beds can be observed
owing to the alternation of fine and coarse bands. A lateral gap, at
another locality further east, shows that the banding is persistent on
both sides of the gap. The dip given by this banding is 50° S.E.
At the extreme southerly bend ofthe river the grit becomes much
less felspathic, approximating more nearly to a quartzite. ‘I'he rock
weathers almost white, and on breaking shows crystals of opalescent
quartz. This type of rock is predominant on the south-east bank of
the river. Near the farm of Pen-y-bont (also on the left-hand side
of the river) there is another exposure of quartz grit. It forms
a small island bounded on one side by the river and on the other side
by a ‘“‘cut out” or old overflow channel. The line of outcrop here
trends 20 N. of E., and the beds are very nearly vertical. This does
not agree with the observations in the main mass.
(iii) Purple Slate—For some distance beyond this grit the land is
completely under cultivation and no exposures are visible. However,
in a well that was dug in 1913 in the school playground at Bryn-
eurau (500 yards south-west of Craig-y-Dinas) purple slate was
24 HEH. W.Hughes—Geology of Part of Carnarvonshire.
reached. Exposures of purple slate also occur in the meadow below
Coch-y-big, and also near the outhouses at Llech-y-dwr.
The dip of the slate cannot be ascertained, but the position of the
three exposures gives some indication that the strike here is similar
to that of the Cambrian slates in the Nantlle Valley—namely
N.N.E.-S.S.W. If this were the case, purple slates would be
present at a point within 300 yards of the grits at Craig-y-Dinas, in
the exact position in which they should stratigraphically occur.
Unfortunately the exposures are not sufficient to verify this. The
Survey memoir mentions Llwyd-coed (2 miles to the north-east) as
the most southerly exposure of the Cambrian purple slates.’
(iv) Green Slate.—One hundred yards due east of the exposure of —
purple slate at Llech-y-dwr the one already referred to at Pentwr is
found. This exposure shows a band of fine grit in green slate, both
macroscopically very similar to the grits and green slate that overlie
the purple slate both in the Nantlle and Llanberis quarries. Still
further east, 60 to 70 yards away, near Ysgubor- Wen, there is also
an exposure of green slate. As already mentioned, the weathered
surface shows the cleavage to strike E.N.E.-W.S.W., but the dip of
the beds cannot be determined in such a small exposure.
No further exposures of any description are to be seen in this
neighbourhood until we come to the hill of Y Foel. The whole of
this hill consists of black slate showing poor cleavage and containing
iron pyrites in large quantity. These slates are put down as of
Ordovician age in the Geological Survey map, but no fossils have
been obtained here. They closely resemble the black slates in the
quarry to the south-west of Cil-y-Coed.
EXPLANATION OF PLATES.
, PLATE I.
Fie. 1.—Quartz-rhyolite, Cil-y-Coed. Showing two large crystals of corroded
quartz (a) and (b); fluxion structure (c) winding round a crystal of
muscovite on the left and of orthoclase (d) on the right. Natural light.
x 18.
,, 2.—(Fig. 1 above, under crossed nicols.) Showing microspherulitic
structure. The quartz crystal (a) and the orthoclase crystal (d) are the
same as in Fig. 1. The flow-structure (c) is still evident. x 18.
», 3.—Rhyolite, Cil-y-Coed. Showing very small spherulites (d) and fluxion
structures (b); also porphyritic crystals of biotite (a) and orthoclase (c).
Natural light. x 18.
,, 4.—(Fig. 3 under crossed nicols.) Showing microspherulitie structure
(a) and (b). x 80.
,, 5.—Rhyolite, Cil-y-Coed. Showing slight flow-structure (b) ; phenocrysts
of plagioclase (a) and quartz (c), corroded and invaded by the groundmass.
Crossed nicols. x 18.
,, 6.—Conglomerate, Cil-y-Coed. Showing a chip of felsite (a) ; quartz (d) ;
and an angular chip of tuff (b) containing a quartz crystal (c) and a
decomposed felspar (e). Natural light. x 18.
PAPE Tale -
,, 1.—Matrix of conglomerate, Cil-y-Coed. Containing subangular quartz
crystals (a) and grains of felsite (b) and (d) in an abundant sericitiec
matrix (c). Natural light. x 18.
1 See extract on p. 21.
Dr. Walcott’s Cambrian Geology & Paleontology. 25
Fic. 2.—Matrix of conglomerate, Cilgwyn. Containing subangular quartz
erystals (c) and grains of felsite (a) in an abundant sericitic matrix (6).
Natural light. x 18. . ‘
», 8.—Quartz grit, Cil-y-Coed. Containing angular quartz crystals (c)
embedded in a felspathic groundmass; small grains of felsite (rather
decomposed) (a); occasional felspars (6); and abundant iron-ore (d).
f Natural light. x 18.
», 4.—Quartz grit, Bwlch-y-llyn. Containing angular quartz crystals (a)
embedded in an abundant matrix (c) now largely decomposed into sericite..
Abundant iron-ore (6). Crossed nicols. x 18.
», ).—Sheared quartzite, Cil-y-Coed. Crossed nicols. x 18.
», 6.—Sheared quartzite, Bwleh-y-llyn. Crossed nicols. x 18.
(To be concluded in owr next Number.)
V.—Dr. Cuartes D. Watcorr’s CamBrian GEOLOGY AND
PaLmontToLoey.!
By V. C. ILLING, F.G.S.
O the student of Cambrian geology, the writings of C. D. Walcott
are always matters of enlightening study, not only for the
matter they contain but also because they combine that admixture
of stratigraphy and paleontology in which the latter, though
accorded a prominent position, is always used to the full to subserve
the wider claims of the former. |
In a consideration of the series of papers on Cambrian Geology
and Paleontology in the Smithsonian Miscellaneous Collections, the
subjects covered are so varied and extensive that only a few of the
more salient points can be considered. Perhaps it will be most
convenient to discuss the material under the two general considera-
tions of the more purely paleontological and the stratigraphical.
Among a series of new forms, some of the most remarkable are
a number of Merostomata, Malacostraca, Holothuroidea, and Annelids,
found in the Burgess shale of the Stephen Formation in British
Columbia. In many cases the impressions of the organic structures
are beautifully preserved in the fine-grained material, a fact to which
full justice is done in the figures. The Merostomata are particularly
interesting in this connexion as indicating to what a degree of
development these Middle Cambrian faunas had attained. But to the
stratigrapher it is the trilobites to which the main interest generally
attaches, and among the various groups the Mesonacide or Olenellidz
stand out in their interest andimportance. This family, characterized
by its large head, large crescentic eyes, rudimentary facial sutures,
genal spines, and long and variable thorax, has now been divided
into a number of genera based mainly on variations in the thorax.
Walcott recognizes six main stages in the development in an order of
decreasing number of thoracic segments.
1. Nevadia Stage. The seventeen anterior thoracic segments are
of the usual type, but are followed by eleven primitive posterior
segments with spinous extensions.
2. Mesonacis Stage. The first fifteen segments are normal, except
the third, which is enlarged, and the fifteenth, which has a median
spine. The ten posterior segments are normal in shape but small.
1 Smithsonian Miscellaneous Collections, 1910-15.
26 Dr. C. D. Walcott’s Canibrian
3. Hlliptocephala Stage. The first fourteen segments are of the
uniform type, while the posterior five segments are short and have
long median spines.
4. Holmia Stage. The sixteen segments of the thorax are all of
the uniform type.
5. Pedeumias Stage. The third segment is enlarged and the
fifteenth segment is developed into a long spine. Beneath and
behind this spine there are from two to six similar but smaller
spines.
6. Olenellus Stage. There are only fourteen segments, of which
the third is enlarged; the fifteenth segment has developed into
a strong telson.
These changes in the thorax are sufficiently marked to form good
generic delimitations in most families of trilobites, but it seems
possible that the Mesonacide were undergoing rapid evolution; thus
Olenellus thompsoni goes through a Holmia and Psdeumias stage
before reaching the true Olenellus stage, and it may be that the
discovery of new material will produce adults of transition stages,
which will make generic identification difficult where genera have
been made somewhat lavishly. It cannot be assumed that the
collections of these Lower Cambrian forms are within measurable
distance of completion.
A tentative sub-zoning of the Lower Cambrian is suggested by
Walcott, based partly on the known stratigraphical occurrences ot
the Mesonacids in the few rare instances where successive forms
exist in the same region, but mainly on the order of development.
D. Olenelius Zone (Upper).
C. Callavia Zone.
B. Llliptocephala Zone.
A. WNevadia Zone (Lower).
It will be interesting to find how far this tentative scheme will stand
the test of future work. In Europe there are at present no positive
facts by which the merits of the classification can be tested, but the
series of beds of the Solva type of lithology, which occur in Wales
and at Nuneaton in the English Midlands, are suggested as a hunting-
eround—we cannot call it a “happy” one—which ought to be
exhausted:
Another subject of general interest is the sudden appearance of life
in the Cambrian period, which has for long engaged the attention of
geologists, and acted as a harmless safety-valve when the impetus to
theorize would not be denied. But in the case of the papers under
discussion, behind the explanation there is a unique knowledge of
the stratigraphical relationships of the Cambrian and pre- -Cambrian
rocks in North America, coupled with the new light shed on Cambrian
stratigraphy by the recent researches of Mr. Bailey Willis and
Mr. Blackwelder in China and of H.M. J. Deprat and H. Mansay in
Yun-nan. The suggestion that there is an extensive break in the
succession between the Cambrian and pre-Cambrian in all known
localities, and that the Algonkian deposits are all epicontinental,
appears to be the most probable explanation of the sudden appearance
of prolific organic life in the Lower Cambrian. However, there
Geology and Paleontology. 21
must still remain the reservation that there is room for many
important discoveries in the pre-Cambrian sediments; and although
the contention may be true in the main, we may still find the
progenitors of the Cambrian types in pre-Cambrian sediments situated
in favourable localities, i.e. as distant as possible from the centre of
the pre-Cambrian shield and beyond the limits of the Algonkian
continents. .
The present best-known pre-Cambrian fossils are the Peltina of
the Belt series, but as an interesting supplement to the recent
researches of Professor Garwood on the importance of the work of
alge in the formation of the geological record, Walcott describes
a series of forms which he compares to the Cyanophyicee in the
limestones of the Belt series and other Algonkian deposits of the
Cordilleran region. Apart from these and a few rather doubtful
eases, fossils are conspicuously absent in the pre-Cambrian. At the
same time a break appears to exist between the pre-Cambrian and
Cambrian in Asia, North America, and Europe. In Eastern Asia, as
far as the evidence at our disposal will allow us to speculate, north-
ward transgressive movements seem to occur in Lower and Middle
Cambrian times, the transgression being continued into Upper
Cambrian times. A similar set of movements are found in North
America with minor oscillations and local regressions in Middle
Cambrian times. In Europe there is a suggestion of similar
conditions, a basal unconformity, a set of shallow water and laterally
varying Lower and Middle Cambrian deposits with abundant non-
sequences (some parts of the Middle Cambrian are more extensive
and suggest open waters, but not deep waters), and an important
transgression in the Upper Cambrian. Thus the Cambrian period in
all three regions represents a time of great oscillatory transgressive
movements culminating in the Upper Cambrian, during which the
great Algonkian continents were invaded by shallow seas in which
marine faunas thrived and multiplied.
The record of this oscillatory but generally progressive submergence
is shown not only by the stratigraphical relationships of the strata,
the proved disconformities and overlaps, but appears also in a general
survey of the geological provinces of this period. Taking NorthAmerica
and Hastern Asia for example, the Lower Cambrian faunas can be
broadly grouped into two main provinces, the North American with
Olenellus, etc., and the Eastern Asiatic with its peculiar form
Redlichia. In Middle Cambrian times there are again two broad
subdivisions, the Pacific and Atlantic, but the dividing line has
shifted eastward into the American continent, and the faunas are
more varied as a result of the wider extent of shallow seas. During
Upper Cambrian times there is a general merging of the various
faunas, and the differentiation into provinces becomes indistinct. —
The history of the faunas is an indication of the history of their
habitat, and this Cambrian record indicates the migration and then
the breaking down of barriers, the gradual evolution of a narrow
strip of shallow seas on the border of large continents, to an epoch of
shallow seas and islands, and finally wide marine areas merging and
growing around much diminished continental areas.
28 Notices of Memoirs—Carboniferous Flora at Gullane.
NOTICES OF MEMOTRS.
—~>—_—_
J.—Rerporr or tun ComMITrEE FoR INVESTIGATING THE Lower
CarponiFERous Frora av GULLANE.'
Consisting of Dr. R. Kidston (Chairman), Dr. W. T. Gordon (Secretary),
Dr. J. 8. Flett, Professor E. J. Garwood, Dr. J. Horne, and Dr. B. N.
Peach.
NEW discovery of petrified plant-remains was made, in 1914,
ata point below high-water mark near Gullane, Haddingtonshire.
The place could only be reached at certain states of the tide. In
order to accelerate collecting, blasting operations were proposed, and
a grant voted at last meeting of the Association to meet the expenses.
The locality, however, lies within the area of the Forth Estuary,
and, although the military and police authorities readily gave per-
mission to blast on the foreshore, it was considered inadvisable to act
on that permission meanwhile. No part of the grant was used
therefore, but sufficient material has been collected to amplify
considerably the data already obtained. Some 150 thin sections.
of the material have been prepared and examined.
The flora represented in these sections is as follows :—
Lepidodendron veltheimianwn, Bensonites fusiformis, R. Scott.
Sternb. Pitys prumeva, Witham.
Stigmaria ficoides, Sternb. Pitys day, sp. noy.
Botryopteris (?) antiqua, Kidston. Pitys, sp. nov.
Chief importance is attached to the specimens of Pitys, as so many
well-preserved specimens have never been obtained elsewhere.
Many of these examples had the bark preserved, while one of them
consisted of a branch tip still clothed with needle-like leaves. Much
light has been thrown on the stem structure of the genus, while the
details of the connexion of leaf and stem have also been determined.
As regards the other plant types represented, it is interesting to
note the similarity between the whole assemblage and the flora of
the Pettycur Limestone at Pettycur, Fife. Indeed, the form
Bensonites fusiformis, R. Scott, has not, so far, been recorded except
from Pettycur. Both Gullane and Pettycur lie on the Forth, and
the geological horizon of the rocks at both localities is not very
different, so that the similarity of the floras is not surprising.
The specimens from Gullane occur in a greyish-white clastic rock,
which on examination proved to be a highly decomposed volcanic ash.
It is suggested that the decomposition of the ash, by vapours emitted
from the voleano during its activity, produced solutions of mineral
matter which caused the petrifaction of plant fragments included in
the ash. These plant fragments occur quite sporadically through the
rock, and they have evidently not been drifted in water. The
petrifying solutions have been both calcareous and siliceous, so that
some specimens are preserved in carbonate of lime, others in silica,
while a few are partly in the one and partly in the other.
The perfection of the preservation is very striking, and it is
proposed to continue collecting specimens when possible.
1 Read before the British Association, Section C (Geology), Newcastle, 1916.
Notices of Memovrs—The Paleoliths of Farnham. 29
I].—Tae Patmorirus or Farnuam.! By Henry Bory, F.G.S.
HE information contained in a previous paper on the same
subject (Proc. Geol. Assoe., vol. xxiv, pp. 178-201) is here
revised and enlarged. The implements of the Alice Holt Plateau
(ineluding Terrace A) are usually large (5 to 8 inches long), and very
few are later than the Chellean period. On Terrace B, on the
contrary, the majority of unabraded implements are small (3 to
4 inches long), and quite 40 per cent are Acheulean. ‘here are also
many flakes, used as scrapers, which may be Mousterian. ‘Terrace C,
beyond a few Le Moustier flakes, yields no clear evidence of its age;
but it is not impossible that the valley may have been excavated to
this depth in early Chellean times. On ‘Terrace D unabraded
implements are extremely rare, but among them are a few which
may be of Le Moustier age. Another terrace (EK) about 20 feet above
the river is covered with a thick layer of drift, but has so far only
yielded one implement.
REV LewSs-
I.—A prAcTocLzEIDUS TERETEPES: A NEW OxrorDIAN PLEsIosauR
In tHE Hounrertan Museum, Guascow University. By W. R.
Smetiiz, M.A., B.Sc. Trans. Roy. Soc. Edin., vol. li, pt. iii,
LOMG:
N this paper the author gives a very detailed account of the
remains of a Plesiosaur collected by Mr. A. N. Leeds in the
Oxford Clay of Peterborough. The skull and caudal region are
missing, but otherwise the “skeleton is nearly complete. In many
respects this form is intermediate between Cryptocleddus and Tricleidus.
Thus, in the fore-paddle the humerus articulates distally with the
madius, ulna, pisiform, and a small accessory ossicle, as is the case in
Triclecdus. On the other hand, in the shoulder-girdle the inter-
clavicle is very small or absent, and the triangular clavicles meet
extensively in the middle line as in Cryptocleidus. For these and
other reasons the author has established a new genus for the reception
of this form. Many of the characters, however, which are regarded
as indicating the higher organization of this type, are certainly merely
the result of the great extension of the ossification of the bones
consequent upon the advanced age of theindividual. Such characters
are the extension forward of the scapule in advance of the clavicles,
and the elongation of the dorsal rami of the scapule and of the
postero-lateral processes of the coracoids.
This interesting paper is illustrated by nine text-figures and one
plate.
1 Read before the Geologists’ Association, December 3, 1916.
30 Reviews—Geology of Ben Nevis.
II.—Tae Grotoey or Ben Nevis anp Guun Coz (Explanation of
Sheet 53). Memoirs of the Geological Survey, Scotland. By
E. B. Bartny, M.A., and H. B. Mavre, M.A.; with contributions
by, Cre 0. CroveH, J.8. Grawr Wison, G. W. Grabyam, M.A.,
H. Kywaston, B.A., and W. B. WrieHt, B.A. pp. 247, with
12 plates. 1916. Price 7s. 6d.
f{\HIS memoir describes the geology of the region that contains the —
highest mountain and perhaps the wildest and most rugged
country in Great Britain. All phases of its geology are replete with
interest.
The area is a greatly dissected part of the main Highland plateau,
with a summit level of about 3,000 feet. Ben Nevis and other high
peaks rising above this level are regarded as features dating from an
earlier geographical cycle. Loch Linnhe, lying in a north-easterly
direction along the shatter-belt of the Great Glen, divides the
area into two unequal parts. Another system of valleys runs
W.N.W.-E.S.E.; and these remarkable ‘through’ valleys, cut
athwart the grain of the country, are consequent upon the pre-glacial
uplift of the Highland plateau. Glacial erosion is believed to have
cut off spurs and thus widened the valleys. In some cases it is
responsible for hanging valleys, although general deepening of valleys
by ice action is considered improbable. A large part in breaking up
the ‘through’ valleys into segments is attributed to the formation of
pre-glacial delta-watersheds or corroms. While accepting many of
Professor J. W. Gregory’s views as to the origin of fiords, the authors
are not inclined to attribute so much potency as he does to earth-
movements (gaping faults and joints) in the development of the
typical West Highland fiords.
The subject of prime interest in this memoir, however, is the structure
and succession of the Highland Schists. These rocks form the basement
of the whole district, but are partly covered by extensive outpourings
of Old Red Sandstone lavas (Glen Coe and Ben Nevis), and are
intruded by great masses of plutonic rocks, principally granite (Ben
Cruachan, Ballachulish, Ben Nevis). The Highland rocks consist
of alternations of phyllite, mica-schist, and “quartzite, with thin
horizons of limestone which form good datum-lines for the inter-
pretation of the structure. The folding of the rocks is very complex.
Mr. E. B. Bailey has developed the view that the rocks are arranged
in a number of great recumbent folds, which are frequently ruptured
along fold-faults or slides. In certain cases the major folds have
been bent into later secondary folds, and have been dislocated by
ordinary faults. In consequence of the extraordinary inversion and
repetition the beds have suffered, the original stratigraphical sequence
is doubtful, and it is not known which is the top or bottom of the
list of formations. As usual, in the interpretation of regions of
extreme complexity such as this, differences of opinion arise; and in
regard to the Kinlochleven district Mr. Carruthers holds views at
variance with those of Mr. Bailey. The chief difficulty appears to
be the number of formations recognized by the respective observers.
Mr. Carruthers increases the number of stratigraphical horizons and
Reviews—Geology of Ben Nevis. 31
consequently diminishes the complexity of structure. Without
special knowledge of the area it is impossible to decide between the
rival views. Mr. Bailey, however, accepts Mr. Carruthers’ interpre-
tation as on an equal footing with his own for the district in question,
his own view being based on a restricted sequence and greater
structural complexity.
The interest of the region is well maintained in the next series of
rocks, the Old Red Sandstone lavas which centre about Glen Coe and
Ben Nevis. They consist of hornblende-, pyroxene-, and biotite-
andesites, with rhyolites, and have been poured out on to a very
uneven surface of the Highland schists. The two great areas of lava
in this region, although forming the highest ground, owe their
preservation to subsidence within great circular faults. One of these
encircles the Glen Coe lavas, except on the south, where the fault-
line is broken through by the Cruachan granite. Igneous material
rose along the peripheral fault during subsidence, but never penetrated
to the inner side of the fault plane. The fault intrusion is chilled
against the fault plane, and is usually separated from it by a band of
flinty crush-rock produced by the friction of the subsiding mass.
Both the larger granite masses of the region show distinct inner
and outer portions, of which the former are the younger. They are
interpreted as magmas which filled the voids caused by successive
cauldron-subsidences. The concentric arrangement of the Ben Nevis
granites and lavas is explained in this way. The magmas are
believed to have been emplaced largely by the stoping method
described by Daly.
The detailed petrography of the Old Red Sandstone igneous rocks is
dealt with in a separate chapter. Their composition is illustrated
_ by a fine series of new chemical analyses. There is a useful |
historical account of the terms granite, granitite, tonalite, adamellite,
banatite, granodiorite, etc., but the conclusions adopted as to their
scope are open to criticism. Two new rock names, aplogranite and
appinite, have been invented, but their definitions are at once too
vague and broad to be of much use. The uselessness of measuring
the quantitative relations of the minerals of igneous rocks by the
recognized micrometric methods is illustrated by a highly fallacious
diagram.
The various granites of the region have produced remarkable
metamorphic effects on a great variety of rocks, including schists,
sediments, and igneous rocks. These are dealt with in a chapter
which is a distinct contribution to the literature of contact
metamorphism.
A group of W.N.W. dykes of dolerite, basalt, and monchiquite are
regarded as of Tertiary age. A small explosion vent in the Allt
Coire na Ba may also be Tertiary. The breccia is invaded by a basic
rock which proves to be a fresh nepheline-basalt.
The final chapters deal with the glacial phenomena and with the
economic products of the area. Roofing slates and granite are
quarried on a comparatively large scale at Ballachulish.
The memoir, which has been edited and mainly written by
Lieut. E. B. Bailey, is excellently illustrated by twelve fine plates
32 Reviews—Late Pleistocene Oscillations
and numerous maps and diagrams. The Scottish Survey geologists
are to be congratulated on the memorable results of a long, patient,
and intricate piece of work.
Gi Wes
Il[.—Lare Pretsrocene Oscmnarions oF Sua-LEVEL IN THE Orrawa
Vatiny. By W. A. Jounsron. Geological Survey of Canada,
Museum Bulletin No. 24; 1916:
ies the attention of British geologists is at the present
time mainly directed to economic problems, it is nevertheless
very desirable that a paper of such scientific importance as that
about to be discussed should be brought to their notice. ‘The author
has made a notable contribution to the study of late-glacial changes
of sea-level, and the facts he has put on record might almost be said
to constitute a complete demonstration of the applicability of the
theory of isostasy to these changes.
It will be recalled that this theory ascribes the raised or tilted
shorelines which are found around the centres of glacial dispersal to
the sinking in of the earth’s crust beneath the pressure of the ice-
sheets, and its subsequent recovery when the ice has melted away.
The depression and recovery were greatest at the centres of dispersal
where the ice was thickest, with the consequence that the shorelines
are highest near these centres and descend gradually towards the
margins of the glaciated districts. Before they reach these margins,
however, they invariably pass beneath the present sea-level. ‘There
are no late-glacial raised beaches in the peripheral parts of the
glaciated districts, the shorelines which were formed during the
retreat of the ice from these areas being all beneath the present sea-
level. This relation indicates very clearly that the general sea-level
must have been considerably lower during the earlier stages of retreat
than at the present day, and the same conclusion can be arrived at
on @ prior’ grounds by considering the effect on the ocean-level of
the binding up of enormous quantities of water in the ice-sheets.
We have, therefore, in seeking for an explanation of the late-glacial
changes in the relative level of land and sea, two factors to deal with.
The first is the isostatic recovery of the earth’s crust, the second is
the general raising of level of the ocean due to the melting of
the ice-sheets. According as the first or second of these factors
predominated there occurred either emergence or submergence in the
isostatically affected areas.
This appears to be the explanation of the curious fact established
by Brogger in the Christiania region, that the first change of level
after the retreat of the ice was one of submergence, ice at
a somewhat later stage of retreat, gave place to emergence. That
this is the course of events to be expected from the interplay of the
two factors mentioned is apparent from the following considerations.
1. At the period of deposition of the earlier late-glacial marine
deposits from which Brogger drew his conclusions, about one-third to
one-half of the total retreat of the ice-margin had been accomplished;
and it is roughly at this stage of retreat, when the climate had
already considerably ameliorated, and there was at the same time
&
of Sea-level in the Ottawa Valley. 33
a large body of ice still in existence, that the most rapid return of
water to the ocean is to be expected.
2. Brogger has clearly established that the isostatic recovery
progressed with a wave-like motion from south to north along the
Cattegat, following up the retreating ice-margin. This seems to
indicate that the recovery takes some time to get under way, and
does not attain its maximum rate until the neighbourhood is altogether
clear of ice.
At this particular period of the retreat, therefore, it would be
natural to expect that the rise of the ocean level might be, for a time,
faster than the isostatic recovery, and submergence would result.
.. ater, when the isostatic recovery had gathered pace and the amount
- of water returning to the ocean from the waning ice-sheets had
become gradually less, we might expect the isostatic recovery to
attain the upper hand and give us progressive emergence.
Now the best test of the validity of this theory is its applicability
to the isostatically affected areas of the British Isles and North
America. Unfortunately, inthe British Isles the highest late-glacial
shoreline is only 100 feet above the present sea-level, and within this
small vertical range evidence of the kind utilized by Brogger is not
to be expected. In North America, until the appearance of the
paper under review, no investigation, such as would bring to light
a relation of this nature, appears to have been placed on record.
Johnston now brings forward evidence, of a nature similar to that
adduced by Broégger, to show that the late-glacial changes of sea-level
in the Ottawa Valley were precisely the same as those established
for the Christiania region, namely, that the sea first rose on the land
as the glaciers retreated, and that it was not until a later date that
emergence supervened. Moreover, he makes a further point of
great importance in establishing the isostatic theory on a firm basis.
This point, for which there was no direct evidence in the Norwegian
ease, is to the effect that the tilting of the Great Lakes region was in
progress before and during the rise of the sea in the Ottawa Valley,
for, presumably from a consideration of contemporaneous ice-margins,
it is concluded that ‘‘ the Ottawa Valley must have been, in part at
least, occupied by the ice-sheet during the existence of Lakes Iroquois
and Algonquin, and at least a small amount of uplift affected the
region at the foot of Lake Ontario during the life of Lake Iroquois.
Uplitt also affected the northern portion of the Great Lakes region,
and probably included the upper portion of the Ottawa Valley near
Mattawa during the existence of Lake Algonquin, and while the
ice-sheet still occupied the upper portion of the Ottawa Valley”
' Further, it is not a case of alternating elevation and depression,
‘‘for the results of investigations by numerous geologists, of the
raised beaches of the Great Lakes region, has shown that differential
uplift took place almost continuously as the ice withdrew.”
We thus have direct proof that a district which was rising
relatively to those around it was nevertheless undergoing submergence
beneath the level of the sea, that in fact the two Paginse eared to
explain the late-glacial changes of level were in action simultaneously
in the same region.
DECADE VI.—VOL. IV.—NO. I. 3
34 Reviews—United States Geological Survey.
There is now but one thing wanting to make the analogy between
the isostatic phenomena of America and Europe perfect in every
detail, and that is the discovery of a shoreline corresponding to the
‘early Neolithic’ or ‘ Littorina-Tapes’ raised beaches of Great
Britain and Scandinavia. This should represent in the south
a distinct resubmergence, and in the north a pronounced check or
slowing down in the general emergence.
We must congratulate the author of the paper under review on
having made a striking advance in Quaternary geology. Is it too
much to hope that-he will carry his researches further, and complete
the history of the changes of level in his district down to the
present day ?
W. B. Wriear.
TV.—Turrety-stxta AwnvaL Report or THE DIRECTOR OF THE
Unirep Srates GrorocicaL SuRVEY TO THE SECRETARY OF THE
INTERIOR FOR THE YEAR ENDED JUNE 30, 1915. pp. 186, with
2 coloured plates. Washington, Government Printing Office,
1915.
Y its very reticence and conciseness this slender volume is eloquent
testimony to the extensive and multifarious character of the
work carried on by the United States Geological Survey. How large
and useful are the services it renders may be gathered from the
following extract from the opening page of the report itself: ‘‘ The
recognition by citizens generally that the Geological Survey is
a bureau of information as well as a field service has gradually placed
upon it a large burden of work as well as of responsibility. The
amount of correspondence involved in performing this public duty
may be indicated by the fact that approximately 50,000 letters of
inquiry were handled in the different scientific branches of the Survey
last year. The scope of these inquiries is not less noteworthy, for
they range from requests for information concerning the geology of
every part of the United States or the water supply, both under-
ground and surface, of as widely separated regions as Alaska and
Florida, or for engineering data on areas in every state in the Union,
to enquiries regarding the natural resources of foreign countries,
especially those of Central and South America.” So large has the
Survey grown that for convenience of administration it is divided
into six main branches, each of which is subdivided into various
divisions, certain of which are further subdivided into sections.
First and possibly foremost of them comes the Geologic Branch, which
is responsible for the geological work of the Survey. Though it was
primarily formed for the comparatively restricted task of the classi-
fication and examination of the public lands reserved to the state, its
scope has been extended to the preparation of a geological map of the
whole of the United States. The nature of its duties is best set forth
in the words of the Report: ‘‘ At present the geologic branch is not
only the effective agency of the Survey in the geologic investigations
carried on by the Government in all parts of the United States and
Alaska but also the great geologic information bureau to which the
American public, from Key West to Point Barrow and from San
Reviews—United States Geological Survey. 35
Diego to Eastport, applies for knowledge of every sort concerning the
earth’s crust and its mineral constituents. To the people of this
country and, in a surprising degree, to the citizens of other countries,
the Survey is the principal source of geologic information regarding
not only the geology of the United States and its possessions but also
that of Mexico, Central America, and even South America. Through
its correspondence it is asked for data regarding the geology and
mineral deposits of all parts of the world. The geologic branch has
therefore the double task of geologic surveying, including the
investigation, description, and mapping of the geology and mineral
deposits of all parts of the country, the classification of the public
lands, and the publication of the results of its work on the one hand,
and of furnishing to the public miscellaneous geologic information
derived from all sources on the other.” The Geologic Branch is
divided into four divisions, viz. geology, Alaskan mineral resources,
mineral resources, chemical and physical researches, which though
working on independent lines yet co-operate effectively with one
another. We read that the scientific staff of the division of
geology at the beginning of the year consisted of 66 geologists,
33 associate geologists, 26 assistant geologists, 15 junior geologists,
and 22 geologic aids, a total of 162. It must further be
remembered that besides the Federal Survey many, if not all, the
States have their own Bureaus of Mines and Geological Surveys, and
much of the field-investigation and paleontological research has been
conducted in connexion with the local staffs. In order to secure
uniformity in the geological names the question is considered by
a standing committee of the branch, the secretary of which scrutinizes
the nomenclature and classification in all manuscripts submitted for
publication. The work of the division of chemical and physical
research is not wholly confined to the customary routine analyses, but
includes many investigations of considerable scientific interest. The
‘division of mineral resources is responsible for that valuable annual
return entitled ‘‘ Mineral Resources of the United States’’; upon its
preparation no fewer than sixty persons are wholly or partly engaged.
The Topographic Branch is engaged on geodetic work, and up to
date has mapped 40-2 per cent of the entire country; its skilled staff
numbers 159. One of the most important objects of the work carried
on by the Water Resources Branch is the investigation of underground
water with the view of the irrigation of arid areas; the skilled staff
numbers 76.
The fourth Branch, viz. the Land Classification Board, which was
_ the origin of the Survey, collates the results of the investigation of
public lands made by the branches already mentioned. Since the
classifications required by the public lands laws fall into two broad
groups, depending upon the presence or absence of mineral deposits
or of water respectively, the Board is divided into two divisions, the
- one for mineral and the other for hydrographic classification. Last
of all we have the Publication and Administration Branches. The
total expenditure on the whole Survey amounts to nearly one and
a half million dollars.
This is not the place to discuss at length the points suggested by
36 Reviews—Petroleum and Gas Resources of Canada.
this Report or the lessons for ourselves that may be drawn from it,
and we shall confine ourselves to a brief paragraph. There is much
to be said for establishing an institution to serve a similar purpose
for the British Empire—an institution which should ever be ready to
explore outlying and little-known quarters of the Empire, and to
investigate and report upon their resources,'! and which should
cordially co-operate with and encourage the local geological surveys.
Something has already been done, and perhaps as the result of these
tragic days something more may eventuate ; we have at least been |
thoroughly taught the danger of depending solely upon the result of
haphazard individual effort. At the Imperial Institute there is
a small staff under the Colonial Office to undertake investigations of
the kind in point, with particular reference to the Crown Colonies.
Very useful work has been turned out, but all on too small a scale:
the staff is not large enough, and the financial equipment far from
generous or sufficient. Geological surveys exist at home and in the
great dependencies: all work independently and without mutual
co-operation. In Great Britain the Geological Survey, which—
perhaps humorously—is placed under the Board of Education, has
devoted itself to investigations of some scientific interest, but appears
to have carefully avoided the risk of being reproached with doing
anything which might prove of economic value. Only under the
stress of war has it so far broken through its traditional aloofness
from mundane affairs as to issue a series of monographs on the
mineral resources of the United Kingdom. A small and distinct
Survey is maintained in Dublin. To complete the picture of
heterogeneity it only remains to add that the actual working of
mines comes within the purview of the Home Office.
V.—Perroreum and Nartoran Gas Resources or Canapa. By
Freperick G. Crapp and others. Vols. I and II. Canada, Dept.
of Mines, Mines Branch No. 291.
fJ\HAT the various members of the British Empire are alive to the
extreme importance of the question of liquid and gaseous fuel
is shown by the recent activities of the government departments of
the chief self-governing Colonies in investigating their natural
resources of oil and gas. Canada, whose oil industry dates back as
far as 1857 and whose gas industry has now far outstripped the
former in value, and is growing enormously, has rendered a service
to the oil investigator in the publication of two volumes on
Petroleum and Natural Gas Resources of Canada, which, in addition
to a series of general chapters on Petroleum problems, combine in
a very accessible form the available knowledge on the various fields,
and include a series of useful maps.
The first of the volumes deals with general oil and gas problems,
geological, chemical, engineering, and economic, and the composite
authorship gives it this advantage, that the various subjects have
each been considered by investigators and workers in the particular
branch; thus we are spared the anomaly of the geologist writing on
engineering or the engineer writing on geology, with the usual
‘
Reviews—Petrolewm and Gas Resources of Canada. 387
unfortunate results. It would have been preferable to include more
of the Canadian element in the authorship, for certainly in the first
volume the writers appear only at their ease when citing examples
from the United States, but as a general treatise on petroleum
vol. i will probably find a much wider circle of readers than
those interested in Canadian oil-fields. In it are collected what
is really a series of essays on petroleum problems, some of them but
mediocre, a dull restatement of well-trodden ground, but others
distinctly fresh and well-balanced, with clear concise wording -
where descriptive, and full of suggestive ideas where theoretical.
_ It would probably have been of advantage to omit most of the first
chapter, for to summarize the world’s oil occurrences in thirty
pages, country by country, is to attempt the impossible and to
involve the bewildered student in a labyrinth of dead place-names.
Chapter ii contains much useful physical and chemical data, while
under the heading ‘‘ Geological Occurrence of Petroleum and Natural
Gas”, chapter iv, there is a clear and short account of the various
theories of the production of natural hydrocarbons, in which the
' author safely joins both sides of the warring camps of the upholders
of organic origin. But the remarks on oil migration do not break
any fresh ground, and here unfortunately the need is most lamentable.
‘There comes a time in the history of all theories when a few adverse
storms are necessary to unsettle the fallacies which take root
so easily and to orient ideas to fresh facts. It is a pity that the
current ideas of oil migration have lived so long in the belt of calms,
for, strange as it may seem when considering the importance of the
subject, we do not yet know how, when, why, or how far an oil will
migrate. Gravitation, capillarity, different specific gravity of water
and oil (and some authors concede gas pressure) are the sum-total
of the admitted agents on migration, yet it is doubtful whether
any one of these has any primary effect on the initial movements of
the oil, and it is just these which are so important. Gravitation in
‘the accepted sense of the migration theorist requires free pore-space
for downward motion, but water-borne sediments will certainly be
water-clogged in their finer deposits. Capillarity will cause oil to
migrate in fine dry deposits, but it is a movement from the larger
pore-space to the smaller, not from the fine deposit to the coarse, and
in addition there is the same difficulty that the sediments will
almost certainly not be dry. The differential specific gravity of
water and oil will have its expected result in the proper conditions,
i.e. where the pore-space is large enough to allow a certain limited
circulation of liquids, but the hydrocarbons originate in the fine-
grained deposits, and it is just this initial migration from the fine
deposits to the contiguous coarse deposits wherein lies the difficulties
with the present theoretical ideas. When, however, the secondary
processes which take place in argillaceous sediments immediately
after deposition are examined, and the gradual diminution of pore-
_ space during compacting, with its necessary out-pressing of water and
other liquids, is taken into account, it is evident that here is a very
potent factor in the expulsion of liquids from fine material which
is easily compacted to coarse material which is more resistant to
38 Reviews—Johnson & Huntley—Oil & Gas Production.
pressure. There is no doubt that the effect of earth stresses, as
apart from the pressure of the overburden, will have similar results.
Turning now to the chapter on drilling, the 105 pages devoted to
this subject are an extremely useful summary of the methods of
drilling, dealing with the matter in a way which adds interest to
a subject which is usually not very entertaining. The conservation
of oil and gas resources 1s another subject of striking importance.
Vol. ii contains a description of the oil-fields of Eastern and
Western Canada. In Eastern Canada the more important points of
interest are the recently developed gas-field of New Brunswick, and
the possible resources in oil shales in the same province. Ontario
is still the chief oil and gas producer, but of recent years Alberta has
been coming to the fore with a rapid increase in gas production. In
this province the hydrocarbons are obtained from the Cretaceous
Sandstone, at an horizon approximating to the Dakota sandstone. In
Athabaska and contiguous regions there are the extensive outcrops
of asphaltic sands, the so-called ‘‘ Tar Sands”’, while farther north in
the Mackenzie River region wide untapped areas are awaiting further
development.
Vos
VI.—Privertes of Or anp Gas Propucrion. By Roswent H.
Jonnson and L. G. Hunrrey. pp. 371. John Wiley & Sons.
Price 16s. net.
(Y\HE geological aspect of the occurrence of petroleum and natural
gasis by no means overburdened with explanatory textbooks,
and although the volume under discussion deals in addition with
other branches of the oil industry, a large proportion of its pages
is devoted to geological considerations. To the European student it
is also welcome inasmuch as it emphasizes the essentially American’
aspect of the subject, but the widespread occurrence of natural
hydrocarbons in the American Paleozoic leads the authors into
dangerous generalizations. Thus it produces the assertion that ‘it is
probable that a considerable production will some day be developed
in the older formations when they have been thoroughly prospected
in Europe and Asia”; butit must be remembered that the conditions
of occurrence of the Paleozoic rocks in the Central United States have
not their counterpart on this side of the Atlantic, although Asia may
produce many similarities. On the other hand, the long chapter on
the Oil and Gas Fields of North America is distinctly good, and the
chapters dealing with Oil and Gas Reservoirs and the Migration and
Accumulation of Oil and Gas, although necessarily short, contain the
germs of very suggestive ideas.
It is a distinct relief to get away from that obsession for anticlines
which has of recent years somewhat obscured the vision of many
oil-field geologists. ‘lo such an extent has this hypothesis been
taken, that on several oil-fields the converse process of reasoning has
been adopted and the presence of the oil been regarded as suflicient
proof of the occurrence of the anticline. It is by no means suggested
that the anticlinal occurrence of oil and gas is not of great
importance, but the promulgation of the idea of its exclusive
Reviews—Ore Deposits, Rossland, British Columbia. 39
importance is to be deprecated, while the beautifully simple
diagrammatic representation of the successive occurrence of water,
oil, and gas in the arched strata is at its best but a crude and partial
statement of the whole story.
The tendency of modern investigation has been to prove that the
original nidus of the hydrocarbons is the fine-grained sediments, and
that the migration into the coarser and permanently more porous
horizons takes place at an early stage as the result of compacting. |
Many of these porous horizons are quite limited in their lateral
extent, so that the later migration as a result of tilting and folding
movements is often limited, unless abnormal conditions such as
faults and joints produce planes of egress for the gas or oil. Hence
it is found that as a result of variations in porosity and of irregular
deposition of sandy horizons, the primary migration due to com-
pacting is often of more importance in the differentiation of oil into
pools than the later earth movements, which merely localize the oil and
gas in the higher portions of the more porous strata. Of course, in
many cases, the coarse horizons are sufficiently widespread to allow the
anticlinal hypothesis to hold, but the reverse is more common in
nature than is usually suspected. ~
AORN be
V1II.—Geotocy anp Ore Deposits oF Rosstanp, Bririsk ConumBta.
By Cartes Wares Dryspate. Memoir 77 of the Geological
Survey. Ottawa, Government Printing Bureau, 1915. pp. xiv
+ 317, with 6 maps in pocket, 25 plates, and- 26 figures in the
text.
fJ\HE rich district of Rossland, which is situated in the Trail Creek
mining district of the West Kootenay district of British
Columbia, about 6 miles west of Columbia River and 5 miles north
of the International Boundary, produces gold, silver, and copper.
It was discovered in 1890, and has been worked continuously since
1894. In this memoir the region is very fully described. The
-geological features and the mineral enrichment, which present many
points of interest, are discussed in some detail. The district appears
to have been covered by sea during at least part of the Carboniferous
age, and upheaved at the end of the Paleozoic era. An intrusion of
augite porphyry occurred during the Triassic period, and at the close
of the Jurassic period the rock formations were invaded by the Trail
granodiorite batholith, this being the first period of mineralization.
Erosion took place throughout Cretaceous times, and at the end the
whole Cordillera was uplifted and the present ranges were outlined.
The second main period of mineralization occurred in Miocene time.
During the Pleistocene a change to a glacial period took place.
The ore consists of pyrrhotite, chalcopyrite, pyrite, and marcasite,
with a little arsenopyrite, molybdenite, and bismuthinite, in a
gangue of altered country rock, containing some quartz and locally
a little calcite. The deposits resemble in many respects the well-
known ones at Namaqualand, Cape Colony, and possess some structural
features in common with those at Butte, Montana.
40 Reports & Proceedings—The Royal Society.
VIII.—Unirep Sratzs Survey: Ruopr Istanp Coat.
N Bulletin 615 of the U.S. Survey, Mr. George H. Ashley gives
an account of Rhode Island Coal, the interest of which is
mainly economic, the conclusion being drawn that the coal cannot
compete with that produced by New England and Pennsylvania.
The coal has an unusually large range, character, and quality,
varying from anthracite to graphite, and contains a high percentage
of ash and moisture. The coal beds, which were originally of
moderate thickness, have been so folded and compressed that, while
in places large pockets have been formed, elsewhere they have been
nearly altogether squeezed out. The coal ignites slowly and with
difficulty, and makes so hot a fire as to destroy stove tops and furnace
linings.
REPORTS AND PROCHEHDINGS-
LY oe Re
I.—Tne Royat Socrery.
November 2,1916.—Sir J.J. Thomson, O.M., President, in the Chair.
‘‘On the Photographic Spectra of Meteorites.” By Sir William
Crookes, O.M., F.R.S.
Thirty rare earthy meteorites, mostly acquired through the courtesy
of the British Museum Trustees, have been examined.
The paper first deals with a few novel features in the construction
of the spectrograph. The instrument has a train of five double
quartz prisms of the Cornu type, and an explanation of their action
in preventing double refraction is given. The jaws of the slit are
formed of transparent quartz prisms, cut and mounted in such
a manner that the edges appear opaque to light. A device, called
the fixed slit system, is described, by which all uncertainty caused by
variation in the width of the slit in various experiments is removed.
The aerolites were all examined for occluded gases, especially with
negative results for any inert gases that might be present. The
spectrum tubes showed only compounds of hydrogen, carbon, and
sulphur, and a little free hydrogen. The are spectrum of each
aerolite has been photographed from the region of the ultra-violet to
the end of the visible.
The aerolite was powdered, mixed with powdered silver of known
purity, and formed into a cake by hydraulic pressure. This gives
sufficient cohesion for manipulation and enables it to conduct the
current. The resulting spectrum contains, in addition to the lines
of the aerolite constituents, only those due to silver, which are
comparatively few. Examples of these spectra were exhibited.
All the lines given in the are spectra of the thirty aerolites have
been identified, and were shown in the spectrum photographs. The
examination has revealed the presence of unexpectedly large traces
of chromium in all the specimens, a condition quite different to that
found in the siderites or meteoric irons, where chromium is practically
absent.
The proportion between chromium and nickel remains constant in
twenty-six out of the thirty aerolites, and is clearly shown in the
photographs. In three only nickel is almost absent.
Reports & Proceedings—Zoological Society of London. 41
From the experience gained it has been possible to make a mixture
containing known quantities of nickel and chromium, which with
the addition of iron produces a spectrum in the neighbourhood of the
chromium group that is practically identical with that produced by
the aerolite Aubres.
II.—Zooroetcat Socrery or Lonpon.
November 21, 1916. —Dr. S. F. Harmer, M.A., F.R.S., Vice-President,
in the Chair.
“On the development from the matrix of further parts of the
skeleton of the Archeopteryx preserved in the Geological Department
of the British Museum (Natural History).”’
Dr. B. Petronievics and Dr. A. Smith Woodward, F.R.S., V.P.Z.S.,
read a paper on some new parts of the pectoral and pelvic arches
lately discovered in the London specimen of Archeopteryx. ‘The
coracoid bone most closely resembles that of the ratite birds and
the Cretaceous Hesperornis. The pubic bones are twice as long as
the ischia and meet distally in an extended symphysis, gradually
tapering to a point, which seems to have been tipped by a mass of
imperfectly ossified cartilage.
IiI.—Epiypuren Geotocican Socrery.
November 15, 1916.—Professor Jehu, Vice-President, in the Chair.
The following papers were read :—
1. ‘‘A New Locality for Triassic Reptiles, with Notes on the Trias
found in the Parishes of Urquhart and Lhanbryde, Morayshire.” By
Mr. William Taylor, J.P., Lhanbryde.
Mr. Taylor recorded the discovery, in sandstones about a mile
north of the village of Urquhart, of a nearly complete specimen of
Telerpeton, somewhat smaller than the example described by Huxley
in 1866.
On account of lithological resemblances he correlated the sand-
stones, etc., of Bearshead, Stonewells, Meft, Lhanbryde, and New
Elein with the fossiliferous rocks of Lossiemouth and Spynie, and
concluded that the Trias of Morayshire was cul more extensive than
formerly supposed.
The paper was illustrated by a map siowine the distribution of the
Triassic rocks in the area extending from Lossiemouth and Bearshead
southwards to New Elgin and Lhanbryde. On the map were recorded
ae genera of reptiles found at the various fossiliferous localities.
. ‘*Voleanie Necks in North-West Ayrshire”? (with lantern
ill Bi, By G. V. Wilson, B.Sc., H.M. Geological Survey.
The area between Dalry, i sires and Largs contains the sites
of about thirty volcanoes. In the north the large volcanic centre of
Misty Law is most probably of Calciferous Sandstone age, and gave
rise to the lava-flows of that period in the district. The area to the
south is studded with a number of volcanic necks, all of which contain
ash of a type similar to the interbedded ashes which occur about the
_ position of the Dalry Blackband Ironstone; it was suggested that
some of the necks gave rise to these beds ‘of ash. One neck was
42 Reports & Proceedings—Geological Society of London.
described in which occurred a fallen mass of a coal-seam which had
been large enough to work; fragments of charred wood and rounded
pebbles of biotite, hornblende, and augite also occur in this neck.
In another case marine shells—of a type not later than Millstone
Grit—had been found in the ash of a neck, probably washed into the
crater of a submarine volcano or into one on low-lying ground liable
to submergence. This phase of volcanic activity probably started
soon after the deposition of the Lower Carboniferous Limestones, and
continued intermittently till Millstone Grit times, with quiescence
during the deposition of the Coal-measures; but farther to the south
we have the remains of great volcanic activity during the Permian.
It was suggested that the district at its period of volcanic activity
may have resembled, in some ways, the San Franciscan Volcanic
Field of Arizona.
IV.—Geotocicat Soctery or Lonpon.
1. November 22, 1916.—Dr. Alfred Harker, F.R.S., President,
in the Chair.
The following communication was read :—
‘‘Characeee from the Lower Headon Beds.” By Clement Reid,
F.R.S., F.L.8., F.G.8., and James Groves, F.L.S.
The investigations here recorded have been made at Hordle Cliffs
(Hampshire), where the strata, below the superficial gravel, belong
entirely to the Lower Headon Beds, and consist of freshwater and
brackish-water (more or less calcareous) deposits, laid down ap-
parently in wide shallow lakes and lagoons. Such habitats are the
most favourable to the growth of Characez, and several of the beds
have yielded numerous remains of these plants.
There is a great diversity in the fruits of Chara found, representing
evidently a number of species, belonging to several different sections
or genera. With the exception of a few, which are possibly abnormal
variations, the fruits can be roughly grouped under the following
types :—
I. Tuberculate series. (Type of C. tuberculata, Lyell = Kosmogyra,
‘Stache, emend.)
(a) Spherical.
(6) Obovoid or pyriform, with distinctly prolonged base.
II. Non-tuberculate series.
(c) Large spherical, diam.c. 1mm. (type of C. medicaginula, Brongn.).
(d) Large ellipsoidal (type of C. helicteres, Brongn.).
(e) Medium-sized, subglobose, tapering more or less at both ends.
(f) Cylindric-ellipsoidal, showing more numerous striz.
(9) More or less pyriform: that is, definitely tapering towards the base.
(h) Minute, subglobose-ovoid (long. = c. 350 to 500 u).
It is difficult to determine the exact number of species found, on
account of the extreme variability of some of the forms, but the
authors consider that at least twelve may, for the present, be con-
veniently treated as distinct.
The vegetative remains are comparatively few, consisting of minute
portions of stems and branchlets of different diameters, and these it is
impossible at present to connect with any particular types of fruit.
Reports & Proceedings—Geological Society of London. 43
Though investigations of some earlier formations have shown that
there are extinct forms of Characew exhibiting important points of
difference from their living representatives, the remarkably distinct
and characteristic oogonium of five elongated spirally twisted cells
has remained constant certainly as far back as the Inferior Oolite,
and it is only in earlier formations that any doubt arises as to whether
bodies are or are not Chara fruits.
Characez are found in still fresh or brackish water all over the
world, under widely different conditions as regards heat, ete., and
may therefore be expected to occur in almost all freshwater forma-
tions.
For these reasons it is suggested that the fruits of this group of
plants, when more widely collected, may prove of considerable value
as zonal fossils for the correlation of lacustrine deposits lying in
isolated basins. Doubtless, on account of their small size, the
Characez have in the past often been overlooked.
2. December 6, 1916.—Dr. Alfred Harker, F.R.S., President,
in the Chair.
Mr. G. C. Crick, A.R.S.M., F.G.S., gave an account of some
recent researches on the Belemnite animal. He stated that it was
not his intention to deal that evening with the homologies of the
Belemnite shell or with the phylogeny of the Belemnite group, but to
confine himself to the restoration of a typical Belemnite animal and
its shell, as shown particularly by examples in the British Museum
collection.
He first demonstrated, by means of a rough model, the construction
of the Belemnite shell, including the guard or rostrum, the phragmo-
cone with its ventrally situated siphuncle, and its thin envelope the
conotheca, with its forward prolongation and expansion (on the
dorsal side) known as the pro-ostracum. He then exhibited photo-
graphic slides of examples in the British Museum collection showing
these various characters, and noted the abrupt termination of the
chambered cone on the lower part of the pro-ostracum, of which the
dorsal surface may have been partly or almost completely covered
by a thin forward extension of the guard. To illustrate what was
known of the complete body of the animal as found associated with
the guard, he then showed photographic slides of two of the examples
figured by Huxley in his Memoir on the Structure of the Belemnitide
published in 1864. Each of these exhibited the guard associated
with portions of the pro-ostracum, the ink-bag, and the hooklets of
the arms. The form of the hooklets with their thickened bases was
discussed, this feature in a great measure justifying the attribution
to the Belemnite of certain Cephalopod remains (found practically at
about the same geological horizon) that included uncinated arms
associated with an ink-bag, and frequently also with nacreous portions
of (presumably) the pro-ostracum.
Of the remains of uncinated armed Cephalopods from the Lias,
each exhibiting the same form of hooklets as those figured by
t
44 Reports & Proceedings—Geologicul Society of London.
Huxley, he said that the British Museum collection contained
seventeen examples, all from the neighbourhood of Lyme Regis and
of Charmouth, in Dorset. Kach specimen exhibits a number of
uncinated arms associated usually with an ink-bag, sometimes also
with nacreous matter, and in two instances also with the guard or
rostrum. ‘These two examples were those to which he had already
referred as having been figured by Huxley, and unfortunately the
arms are not well preserved in either of these specimens; in one
(B. bruguiervanus, from the Lower Lias near Charmouth) there are
only a few scattered hooklets, while the arms of the other (2B. elongatus,
from the Lower Lias of Charmouth) are represented only by
a confused mass of hooklets.. Of the other fifteen examples, in one
there are a few solitary hooklets; in another the number of the
arms is very indistinct; in two the remains of only two arms are
preserved ; in one there are traces of three arms; in two there are
indications of three, or possibly four, arms; in one there is
a confused mass of possibly four arms; and in one there are the
remains of four, or possibly of five, arms. In each of the remaining
siX specimens six arms can be more or less clearly made out, while
there is not a single example in which more than six uncinated arms
are displayed.
Of the six examples that exhibit six uncinated arms four are —
stated to be from the Lias of Lyme Regis; one is from the Lias of
Charmouth; and one was obtained from the Lower Liassic shales
between Charmouth and Lyme Regis. From a consideration of these
specimens, the speaker concluded that the Cephalopod represented
by these uncinated arms is the animal known as the Belemnite,
and that the six uncinated arms were arranged in three pairs of
unequal length, of which the longest pair was lateral, the medium-
sized pair probably dorsal, and the shortest pair probably ventral.
He considered the presence of tentacular arms to be doubtful.
These observations were in accord with those of Huxley, who, in his
Memoir already cited, stated that he had ‘‘not been able to make out
more than six or seven arms in any specimen, nor has any exhibited
traces of elongated tentacula, though the shortness of the arms
which have been preserved would have led one to suspect their
existence ’’.
Mr. Crick regarded certain markings sometimes to be seen on the
guard as indicating that during the life of the animal the guard
was almost, if not entirely, covered by the mantle, in which case it
was highly improbable that the guard was pushed into the soft mud
of the sea-bottom in order to act as an anchor.
He considered the animal to have been a free swimmer, swimming
forward ordinarily, but when desirable, capable also of sudden and
rapid propulsion backwards.
V.—Liverpoot GrotocgicaL Socrery.
1. The first meeting of the fifty-eighth session of this Society was
held on October 10 last, Mr. J. H. Milton, F.G.S., F.L.S., President,
occupying the chair. The report on the work of the past session
Reports & Proceedings—Liverpool Geological Socrety. 45
showed that in spite of present adverse circumstances there had
been a slight increase in the membership, and that the activities of
the Society had been well maintained.
The President in his annual address dealt with ‘‘ The Coral Types
of the Carboniferous Limestone”, and gave a very valuable and
helpful résumé of the principal diagnostic characters of the different
genera. The lines of their evolution were traced, and their value as
zonal indices clearly shown. In this connexion a warm tribute was
paid to the work of the late Dr. Arthur Vaughan. ‘The address was
fully illustrated by a beautifully drawn series of sections of the chief
types, and an exceilent collection of specimens from North Wales
and elsewhere.
2. November 14, 1916.—J. H. Milton, F.G.S., F.L.S., President, in
the Chair.
The following paper was read :—
‘‘The Pebbles of the Middle Bunter Sandstones of the Neighbour-
hood of Liverpool.’’ By T. A. Jones.
The author described the results of an investigation into the nature
of the rock types represented amongst the pebbles, which he roughly
classified under the following heads: Quartzites and Grits, Granites,
Mica Schist, Felstones, Tourmaliniferous Quartzites, Grits, Schists,
etc., Fossiliferous Pebbles, and Miscellaneous. Attention has been
given chiefly to those bearing tourmaline, which collectively were
present in greater abundance than those of any other group, with the
exception of the Quartzites and Grits. The mineral was present in
great variety and quantity, and on the whole the rocks showed
marked similarity to those surrounding the granite masses of Devon
and Cornwall, with which they were perhaps still more strongly
linked by the discovery of a pebble of granite containing abundant
tourmaline in slender prisms, and small pinkish garnets. This rock
when crushed yielded splintery fragments of dark indigo blue
tourmaline, closely resembling those found amongst the heavy
density minerals of the finer material of the Triassic sandstones of
the district. A light ash-grey friable schist was also described,
which contained irregular grains of brown and blue tourmaline
apparently of clastic origin, which was also considered competent to
have furnished some of them.
Three other varieties of biotite granite were found, two of them
with micropegmatitic structure. Twelve varieties of felstones had
been examined, all of acid type. Four contained tourmaline plenti-
fully, and two seemed to be tuffs rather than lavas. Among the
fossiliferous pebbles one of reddish quartzite containing a single
specimen of a small Orthis was recorded, the only example so far
known to the author from the local pebble beds.
On the whole the assemblage of pebbles seemed substantially
identical with those of the Midlands as described by Professor
Bonney, although the tourmaliniferous group was judged to be of
greater importance. The paper closed with a brief discussion of the
possible sources of the pebbles, and the method of transport.
\
46 Reports & Proceedings—Liverpool Geological Society.
3. December 12, 1916.—J. H. Milton, F.G.S., F.L.S., President, in the
Chair.
Mr. H. C. Beasley and Professor J. W. Gregory, D.Sc., F.R.S.,
were unanimously elected honorary members. Mr. Beasley has been
an ordinary member for the last forty-six years, during which period
he has been one of its foremost working members, and it has been
a great pleasure to his fellow-members to recognize his great services
to the Society and to local geology.
The recent announcement of the gift of a Chair of Geology to
Liverpool University by Professor and Mrs. Herdman, as a memorial
to their son, was referred to with much interest and sympathy, and
the following resolution was approved: ‘‘That this Society has
learned with much satisfaction of the intended establishment of
a Chair of Geology in the Liverpool University, and has special
pleasure in the fact that the establishment is due to the generosity
of one of its members and past presidents, Professor Herdman, and
Mrs. Herdman, by whose action the long-felt need for the due
recognition of this subject in the University scheme will at length
be satisfied.”
Mr. C. B. Travis, in a ‘‘ Note on Terminal Curvature at Billinge
Hill’’, described an interesting example to be seen near the summit
of the hill, where the outcropping beds of the Lower Coal-measures
are curved over in a remarkable manner by the onward pressure of
the Irish Sea ice-sheet invading the district from the west. This
section has not previously been described.
Mr. F. T. Maidwell followed with an account of recent geological
rambles about Liverpool, in which he threw fresh light on some old
sections, The correlation of the coal-seams in the collieries at
Neston, Cheshire, was dealt with at some length, also the lttle-
known outcrop of Permian strata at Skillaw Clough near Bispham.
VI.—Tuz Wertineron, New Zzatanp, Paitosopuican Sociery
(GroLogicaL Sxcrron).
The annual meeting of the Wellington Philosophical Society
(Geological Section) was held last evening, September 20, 1916, at
the Dominion Museum. Mr. G. Hogben, C.M.G., F.G.S., ’ presided.
The Annual Report stated that during the year seven meetings had
been held, with an average attendance of fourteen. The following
We have been read: ‘A Phase of Shore-line Erosion,” by
. J. A. Bartrum; ‘‘ Terminology for Foraminal Development in
Tees eae ” by "Mr. 8. S. Buckman, F.G.S.; ‘‘ The Continental
Shelf” and “The Motion of Water in Waves”, by ; Dr CL Ae
Cotton, F.G.S.; ‘‘ The Geological Occurrence and Origin of
Petroleum,” by Meas W. Gibson and M. Ongley; ‘‘ The Structure
of the Paparoa Range,” by Dr. J. Henderson; ‘‘An Artesian ‘Trial
Bore at the Westshore, Napier,’? by Mr. R. W. Holmes; ‘“‘ Notes of
a Visit to Marlborough and North Canterbury,” by Mr. P. G.
Morgan, F.G.S.; ‘‘Stage Names applicable to the Divisions of the
Tertiary in New Zealand,” by Dr. J. A. Thomson, F.G.8.; ‘‘ The
Volcanic Rocks of Oamaru,”’ by Mr. G. Uttley, F.G.S.
Obituary—Clement Reid. 47
The election of office-bearers for the ensuing year resulted as
follows: Chairman, Dr. C. A. Cotton, F.G.S.; Vice-Chairman,
Dr. J. Henderson; Hon. Secretary, Mr. KE. K. Lomas; Committee,
Messrs. Morgan, F.G.S., Ongley, Uttley, F.G.S., Holmes, and
Dr. Thomson, F.G.S.
During the evening Dr. J. Allan Thomson read papers: (1) ‘‘ On
the so- cailed ‘Drift Formation’ of Hawera” ; (2) ‘* The Geology of
the Middle Clarence Valley, between the Bluff and Herring River.”
—WNew Zealand Times, September 21, 1916.
OS Ea WeASEuE =
CHENENT REID: FR.S 4 Files. FLG.Ss Ere.
Born JULY 6, 1853. DIED DECEMBER 10, 1916.
Ir is with the deepest regret that we have to record the death of
Mr. Clement Reid, late of H.M. Geological Survey, which took place
at his residence, One Acre, Milford-on-Sea, on Sunday, December 10.
He was buried at Milford on the following Wednesday. Mr. Reid
was so deeply versed in all matters relating to the later Tertiary and
more recent strata that all geologists interested in these deposits will
feel that their science has lost a master and they a reliable co-worker.
Only those who knew Mr. Reid intimately could appreciate his
sterling abilities and intense devotion to his scientific work,
characteristics in which he so much resembled his great-uncle
Michael Faraday.
Mr. Clement Reid joined H.M. Geological Survey in 1874 and
started work, under the able guidance Gratis Be Woodward, in the
South-West of England, but in 1876 was transferred to Norfolk, and
there began, under the same genial leader, the detailed study of the
Pliocene and Pleistocene deposits, including the ‘‘ Forest Bed” and
“Contorted Drifts’’, of the Norfolk coast. The name of Clement
Reid has ever since been intimately connected with the study of
these formations; indeed, in all matters relating to the ‘‘ Norfolk
Forest Bed” and the nearly associated strata he was regarded as the
chief authority. His memoir on Zhe Geology of the Country around
Cromer (Explanation of Sheet 68 E.), together with the maps and
sections, is a model of careful work, and exemplifies the close
attention to minute details as well as the broad grasp of his subject —
_which has ever characterized his scientific work.
Mr. Reid published numerous papers on geological subjects, many
of which are of more than ordinary interest; but as an officer of
H.M. Geological Survey his chief work was the preparation of maps
and. of explanatory memoirs, and for this purpose after leaving
Norfolk he was engaged in later years in Yorkshire, Tsncalneh ne.
Sussex, Hampshire, Isle of Wight, Dorset, Wilts, Cornwall, and the
London area. It is therefore in the publications of the Survey that
the bulk of Mr. Reid’s work will be found, and these chiefly relating
to Tertiary and more superficial deposits.
Whatever Mr. Reid undertook to do he did thoroughly. He was
48 Obituary—Clement Read.
‘
\
always a most careful and untiring worker, and even his times of
relaxation were devoted to some collateral aspect of his work. The
paleontological side of his investigations ‘always gained his close
attention. Quite early in his career he made botany a special study.
Certain seeds found in the ‘‘ Forest Bed” needed determination, and
he began, for comparison, to collect the seeds of wild plants, which
seem at that time to have been strangely neglected, with the result
that he became perhaps the first authority on the subject, and
showed how much information regarding the climate of former times
was to be obtained from fossil seeds. The painstaking work of
himself and Mrs. Reid in the investigation of seeds laboriously
washed out from certain deposits has resulted in the joint publication
of memoirs which may be regarded as monumental 7‘The Fossil
Flora of Tegelen-sur- Meuse,” Verhandl. d. Ko. “Akad. y.
Wetenschappen te Amsterdam, 1907; ‘‘The Preglacial Fauna of
Britain,’”? Journ. Linn. Soc. Botany, 1908; Zhe Pliocene Floras of
the Dutch-Prussian Border, published by the Institute for the
Geological Exploration of the Netherlands, The Hague, 1915).
Mr. Reid’s report upon the Pleistocene deposits at Hoxne was
largely based upon the seeds found in the more peaty parts of these
beds. An exceedingly interesting study of fossil Characez was in
progress by Mr. Reid at the time of his death in conjunction with
Mr. J. Groves, but the results have only just begun to be published.
This work seems to have been initiated by the examination of
silicified slabs of Purbeck rock showing beautifully preserved
sections of Chara stems, which led Mr. Reid to try artificial
weathering by weak acid on some impure limestones, and this led
to important discoveries in regard to anomalous structures in some
of these fossils (see Proc. Roy. Soc., B, vol. lxxxix, p. 252, 1916).
More recently, also in co-operation with Mr. J. Groves, the Chara
seeds from the Headon Beds, near his home at Milford, were
investigated, and a most important paper on the subject was read
before the Geological Society oat a week or so ago, and will, we
hope, be published before jong.
Mr. Clement Reid was elected a Fellow of the Geological Society
in 1875, was awarded the Murchison Geological Fund in 1886, and
the Bigsby Gold Medal in 1897. He served for two periods on their
Council, and was Vice-President in 1913-16. He was elected
a Fellow of the Linnean Society in 1888, and served two periods on
the Council. In 1899 he was elected a Fellow of the Royal
Society. The Royal Geological Society of Cornwall awarded him the
Bolitho Gold Medal in 1911.
Mr. Reid, having joined H.M. Geological Survey in 1874, was
advanced to the post of ‘‘Geologist’’ in 1894, became ‘‘ District
Geologist’’ in 1901, and retired in January, 1913.. Mr. Reid married
Miss KE. M. Wynne Edwards in 1897, and upon his retirement went
_to live at his new residence at Milford-on-Sea, where, after only
three short years, he passed peacefully away in the closing month
of the year 1916.
1 See Reports and Proc. Geol. Soc. Lond., ante, p. 42.
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E. W. Hughes—Geology of Part of Carnarvonshire. 75
Priem! described and discussed similar fossils from the Upper
Silurian of 8. Felix, Laundos, Portugal, and decided that Plectrodus-
proper at least was a jaw, although Selerodus pustuliferus was
undoubtedly part of the cornu of the Cephalaspidian Aukeraspis.
Later studies have convinced me that the true Plectrodus (as
typified by P. mtrabilis) is indeed a jaw, and that it most closely
agrees with the toothed jaws of the Lower Devonian Acanthodian
Ischnacanthus.* 1 am, therefore, much indebted to Mr. W. Wickham
King, F.G.S., for the opportunity of examining the microscopical
structure of an unusually large specimen, probably of a new species,
which he has recently found in the Downtonian of Baggeridge,
S. Staffordshire. ‘The hard base to which the teeth are affixed proves
to consist of almost structureless translucent calcified tissue in which
there are occasional streams of elongated cellular spaces, irregular in
shape, and sometimes with traces of ramifying canaliculi. It thus
agrees exactly with the corresponding tissue in /schnacanthus.
In this connexion it is interesting to add that both in Oesel and in
Portugal separate whorls of teeth such as occur in front of the lower
jaw of Ischnacanthus,* have been found in the same rocks as Plectrodus.*
On the other hand, no typical dermal tubercles of Acanthodian fishes
have hitherto been recognized in any Upper Silurian formation, and
the occurrence of Acanthodian fin-spines is uncertain. We may,
therefore, conclude that the toothed Acanthodians of the Lower
Devonian were preceded in the Silurian by fishes with similar jaws,
but the precise nature of these earlier fishes still remains to be
determined.
VI.—On rae Grotoey or tar Disrricr From Cuin-y-Coxmp 10 tHE
St. Awnes—Luanttyrnt Ripe (CaRNARVONSHIRE).”
By E. WYNNE HUGHES, M.Sc., F.G.S.
(Concluded from January Number, p. 25.)
B. Pre-Camprian, Rayotrric Sertms.—(i) At the south-west end
of the Craig-y-Dinas mass we find exposed a rock similar in every
respect macroscopically to that which is found at Cil-y-Coed.
Unfortunately it cannot be followed far, as the land is ‘completely
under drift, the top of Craig-y-Dinas itself being capped by a thick
layer of drift.
1 F. Priem, ‘‘Sur des Poissons et autres Fossiles du Silurien supérieur du
Portugal’’: Communic. Serv. Géol. Portugal, vol. viii, p. 3, pl. i, figs. 7-10,
1910. ;
2 A. S. Woodward, Catalogue of Fossil Fishes in the British Museum, pt. ii,
1891, p. 20. B. Dean, ‘‘ Notes on Acanthodian Sharks’’: Amer. Journ.
Anat., vol. vii, p. 209, figs. 1-10, 1907. HE. S. Goodrich, in Lankester’s
Treatise on Zoology, pt. ix, 1909, p. 190, fig. 160.
3 A.S. Woodward, Presidential Address, Quart. Journ. Geol. Soc., vol. xxi,
p. lxvi, 1915.
* Campylodus sigmoides, J. V. Rohon, loc. cit., p. 52, pl. i, fig. 25, 1893 ;
G.(?) delgadoi, F. Priem, loc. cit., p. 5, pl. i, figs. 11-15, 1910.
* Plates I and II and two maps, which illustrate this paper, will be found
with the first part in the January Number, pp. 13 and 15.
76 B. Wynne Hughes—Geology of
(1) Five hundred yards almost due north of Craig-y-Dinas, near
the farm of Eithinog-Wen, a small amount of solid rock is present.
A careful examination shows that this rock again compares closely
with the rhyolitic series of Cil-y-Coed. Porphyritic quartz and pink —
felspars can be seen even in hand specimens. ‘lhe groundmass is
fine-grained, compact, and felsitic, differing only from the Cil-y-Coed
rhyolites in its pink eoloration. Beyond EKithinog- Wen a close
search of the slope of the ridge, that runs in a northerly direction
here, disclosed no further exposures. ‘he large amount of debris,
however, that is present everywhere at the foot of the ridge suggests
the presence of the rhyolitic rock.
Qu) At Bryn-mawr, 1,500 yards to the N.N.E. of Craig-y-Dinas
and 1,000 yards from Kithinog- Wen, several rock masses are exposed.
The distance between the first and last of these exposures is fully
600 yards. They all occur near the top of the ridge, and are
undoubtedly portions of the same mass, The line of outcrop, if
continued in a southerly direction, would pass through the exposures
at Eithinog-Wen and Craig-y-Dinas. The largest of these exposures
is the quarry near the roadway close to Glyn-Llifon Park. It is at
present being worked for road-metal. In some cultivated land on
the north side of the road further exposures of this rock are also to
be seen.
In hand specimens all the rocks compare closely with one
another, showing porphyritic crystals of quartz and felspar in a fine-
grained and compact groundmass. Several microscopic sections were
examined, and they bring out the close resemblance between these
rocks and the rhyolitie series at Cil-y-Coed. They show the presence
of porphyritic crystals of quartz and both orthoclase and plagioclase.
The quartz crystals are much more numerous than the felspars, but
many of the latter still show multiple twinning. The groundmass is,
cryptocrystalline, with patches sometimes coarser and sometimes
finer-grained, and it frequently shows good fluxion structure.
GPTS cles io te)
We have here, then, a rock very similar, both macroscopically and
microscopically, to the rhyolitie rocks of Cil-y-Coed.
C. Summary oF tHE Successton.—We have, then, in the area
between Pentwr and Bryn-mawr:—(i) Cambrian: (@) green slates at
Ysgubor-Wen, (4) green grit band at Pentwr, (c) purple slates at
Llech-y-dwr, (d) fine and coarse grits at Craig-y-Dinas, and also
(e) a much cleaved conglomerate at Craig-y-Dinas, all with a dip of
50° $.S.E., lying upon (ii) Pre-Cambrian, (/) rhyolites and tuffs
exposed at Craig-vy-Dinas, Eithinog- Wen, and Bryn-mawr.
D. Retartioy vo rae Surrounping ARnEAS.—(i) South-east of
Pentwr we have already noted the occurrence of Ordovician slates on
Y Foel. These can be traced through Tai-lon to Pen-y-garreg and
beyond.
(ii) Unfortunately the Cambrian slates and grits cannot be
similarly traced to Cil-y-Coed. The strike of the beds in the two
localities suggests the presence of a fault in the intervening country,
but no other evidence of it could be obtained, though this is the
direction of the fault marked on the Survey map (1850).
Part of Curnarvonshire. T7
(il) To the west and north-west the country is flat and low-lying.
No solid rock was found anywhere in this direction.
(iv) The most northerly exposure of the Pre-Cambrian rhyolite
series 1s within 400 yards of the boundary assigned to the St. Annes—
Llanllyfini ridge in the Geological Survey map (1850). The nearest
locality on this ridge where solid rock is exposed is at Pare Pant-dy,
800 yards due east of Pen-y-groes and a mile and a half east of
Bryn-mawr. Referring to the rocks at this end of the ridge, the
Survey memoir states :—
‘Further south the conglomerate forms the highest points of Moel Tryfan
and Mynydd Cilgwyn, where it is partly metamorphosed into a sort of talcose
schist and conglomerate. Beyond this it has been either completely obliterated,
or, curving round to the east near the crest of the hill, it is cut off by a fault
which throws the superincumbent purple slate directly against the porphyry.
It is seen that the grits and lower conglomerates disappear at Mynydd Cilgwyn,
but the purple slates that are interstratified with these follow an unbroken line
to the neighbourhood of the turnpike road near Llanllyfni. The general
character of the porphyry is that of a felsitic rock with an amorphous grey
felspathic base containing small crystals of quartz, which are often somewhat
eranular, sometimes hexagonal, and sometimes they seem to be four-sided
prisms.
* . . . Italso contains small distinct crystals of glassy telspar. The base
of the conglomerate is highly felspathic and sometimes crystalline, enclosing
pebbles of felspathic trap, quartz, quartz rock, purple and black slate, and
jasper. The whole mass is altered, and it is easy to note first: the disappearance
ot the granular structure in the conglomerate or sandy matrix and its gradual
assumption of a porphyritie character, with small crystals of felspar embedded,
while the enclosed pebbles still retain their distinctive form; and again,
approaching the recognised porphyry the hard outlines of the pebbles in the
conglomerate gradually melt away till they become undistinguishable in the
general fusion of the rock, and the view that the porphyry is not an intrusive
mags is aided by the fact that it is impossible to define any line of demarcation
between conglomerate and porphyry.’’ !
Evidently, then, we have on the St. Annes—Llanllyfni ridge
a succession very similar to that at Craig-y-Dinas and Cil-y-Coed.
’ In consequence, the south-west portion of the ridge between Moel
Tryfan and the village of Llanllyfni was carefully examined.
3. Tue Sr. Annes—LiANLLYFNI Riper.
A. Moret Trrran.—The conglomerate at the top of Moel Tryfan
seems outwardly identical with that at Cil-y-Coed. The pebbles are
well rounded and of various sizes, though seldom more than 3 inches
long. They are mainly of volcanic origin and are enclosed in an
argillaceous matrix. There are also quite a number of quartzose
pebbles of a type which is of rare occurrence in the conglomerate at
Cil-y-Coed and Craig-y-Dinas, and the matrix is distinctly more
argillaceous. On the top of Moel Tryfan there are no exposures of
the quartz-porphyry or the quartz grit, but not more than 200 yards
to the east of the conglomerate we find, at the Alexandra Slate
Quarry, a great thickness of purple slate.
From this quarry an adit has been driven east and west right
through the mountain. An examination of the rocks in this adit
shows that a quartz grit occurs here on the eastern side of the
1 Mem. Geol. Stirv., vol. ii, p. 143, 1866.
78 E. Wynne Hughes—Geology of
conglomerate. Both the conglomerate and the quartz grit dip
steeply to the south-east. A. further point of interest is the
existence of several well-marked faults, running north-east to
south-west. These faults have the same direction as the fault
between the grits and the Ordovician slates on the south-east side
of Cil-y-Coed. }
Several thin sections from the conglomerate in the adit were
examined ; they show that the conglomerate bears a close resemblance
to that at Craig-y-Dinas and Cil-y-Coed. Thin sections of the grit
from the two localities are also very similar, though perhaps the
Moel Tryfan grit approximates more closely to a true quartzite.
The adit shows that the whole mass has undergone great dis-
turbance, there being at least six faults visible in the adit, with the
result that the structure is highly complicated. The conglomerate,
for instance, is only 12 feet thick in the adit, whereas on the moun-
tain top it has an outcrop fully 120 feet wide. Between the
conglomerate and the porphyry at the west end of the adit, is
a thickness of fully 200 vards of green slate, grit, gritty slate, and
a green chloritic rock. Whether these slates and grits are Lower
Cambrian or Pre-Cambrian is a question of some difficulty which
I hope to investigate at a future date.
An examination of the adit then shows that—
(a) The conglomerate and quartz grit here bear a close resemblance to those
at Cil-y-Coed and Craig-y-Dinas.
(6) They are in the same relative position.
(c) Their dip, although steeper, is inthe same direction.
(d) As at Craig-y-Dinas, they are overlain by purple slate.
(ec) The conglomerate in the adit does not lie directly on the quartz-porphyry-
(f) The matrix of the conglomerate is more argillaceous than that at Craig-
y-Dinas and Cil-y-Coed.
‘
B. Bwicu-y-tiyy anv Citgwyy.—The conglomerate was traced in
a south-westerly direction. At Bwlch-y-llyn the quartz grit also’
comes to the surface, and is again lying directly upon the con-
glomerate on its south-east side. An examination of microscopic
sections cut from specimens in this locality again brings out a close
resemblance between the grit here and that at Cuil-y-Coed and
Craig-y-Dinas. Like the latter, the grit at Bwlch-y-llyn ranges
from fine to coarse, becoming more quartzitic from north-west to
south-east. (PI. II, Figs. 4, 6.)
From this point on, the conglomerate forms the high ground on
Mynydd Cilgwyn, and it persists in a south-westerly direction along
the whole length of the mountain. On the south-west slopes of the
mountain, however, it disappears in the manner indicated in the
Survey memoir. The pebbles in it, on this portion of the ridge, are
certainly less numerous, but they are decidedly larger than at Moel
‘Tryfan, and, what is still more interesting, the matrix is distinctly
more felspathic. In hand specimens and under the microscope this
gritty matrix could hardly be distinguished from the gritty matrix
of the conglomerate at Cil-y-Coed. (PI. II, Figs. 1, 2.)
- Owing to the presence of several quarries on the east side of the
ridge, the purple slate can easily be traced in a 8.S.E. direction
from Moel Tryfan to Cilgwyn. At Cilgwyn it is exposed at the
4
Part of Carnarvonshire. eae
Old Cilgwyn and Veingoch quarries. ‘The former of there two
quarries lies only 250 yards away from the conglomerate, but does
not expose the grit.
On Mynydd Cilywyn, moreover, the quartz-porphyry is exposed in
several places, always to the west of the conglomerate, but the exact
line of junction could not be seen. Several microscopic sections of
the quartz-porphyry were examined, and here again the resemblance
to the rhyolitic rocks of Bryn-mawr and Cil-y-Coed is most. marked.
The rocks contain porphyritic crystals of quartz and feispar embedded
in a eryptocrystalline matrix which grades to microcrystalline in
a patchy manner. It will be interesting to record here Bonney’s
description of microscopic sections from this ridge. He states :—
.‘*The general type is a compact dull felsite with porphyritic crystals of
felspar and grains of quartz closely resembling some modern rhyolites. On
Moel Gronw angular fragments of a pinkish tint are scattered through the
general mass. Again, some parts are crowded with quartz grains, while others
are comparatively free of these, and occasionally a spherulitic structure is
observed. ‘The rock was probably originally vitreous, and there are abundant
fresh examples of the most perfect flow-structure in the rock.’’ '
This description compares very closely with that already given of the
Cil-y-Coed and Bryn-mawr rhyolitic rocks.
C. Crogwyn Metyn ‘to Carr Encan.—On the southern s!opes of
Mynydd Cilgwyn the conglomerate stops abruptly. All the lower
slones of the hill on this side are composed of rhyolitic rocks very
badly sheared. A careful examination of the area disclosed no
exposure of either conglomerate or grit, although a large amount of
solid rock is exposed, all of which is massive rhyolite becoming more
and more sheared towards the east. As indicated in the Geological
Survey Map the rhyolite in this area is brought up against the
purple slates. The rhyolite was traced through Pare Pant-dy to the
lower roadway going from Pen-y-groes to Talysarn. Here it stops
abruptly. But asmall area of the rhyolite is exposed again at Caer
Engan, 500 yards to the south-east of the nearest exposure in the
main mass. In addition, a very narrow band of the conglomerate
is found on the south-east side. It is badly crushed and the pebbies
almost unrecognizable. The matrix is similar to that at Moel
Tryfan, being argillaceous rather than felspathic. The greater
portion of the hill, however, is composed of a felsitic rock, which
both in hand specimens and in microscopic sections resembles the
light variety at Cil-y-Coed ; but whatever fluxion structure it may
contain is obscured by shearing.
Furthermore, 200 yards to the east of Caer Kngan there is a small
quarry in purple slates, but there is no exposure of grit in the
intervening area.
D. Sommary oF tHe Succession.— We have, then, on the St. Annes—
Llanllyfni ridge—
- (i) Rhyolitic rocks, conglomerate, and quartz grit at Moel Tryfan.
(ii) Conglomerate and quartz grit at Bwlch-y-llyn.
(iii) Rhyolitic rocks and conglomerate at Mynydd Cilewyn.
(iv) Rhyolitic rocks and conglomerate at Caer Engan.
(v) Purple slates all along the eastern side of the ridge.
1 Q.J.G.S., vol. xxxv, p. 312, 1879.
80 Reviews—Dr. John Ball—
IV. Conclusion.
The different formations at all the above localities on the St. Annes—
Llanllyfni ridge lie in the same relative position to one another as
the purple slates, grits, conglomerate, and rhyolitic series at Craig-y-
Dinas, and the grits, conglomerate, and rhyolitic series at Cil-y-Coed.
Further, the different formations are each to each lithologically
similar. This resemblance is well brought out in Plate II, showing
microphotographs of the conglomerate: Fig. 1, from Cil-y-Coed;
Fig. 2, from Mynydd Cilgwyn; the fine grit: Fig. 3, from Cil-y-Coed ;
Fig. 4, from Bwlch-y-llyn; the coarse grit: Fig. 5, from Cil-y-Coed ;
Fig. 6, from Bwlch-y-llyn.
The evidence seems, therefore, conclusive that the series at
Cil-y-Coed and Craig-y-Dinas are of the same age as those of the
St. Annes—Llanllyfni ridge. Accepting the view, usually held, that
the porphyry on this ridge is pre-Cambrian and that the conglomerate
is basal Cambrian, we have—
1. At Cil-y-Coed—Lower Cambrian grits and conglomerate lying on Pre-
Cambrian rhyolites and tufts.
2. At Craig-y-Dinas—Lower Cambrian green and purple slates, grits, and
basal conglomerate lying on Pre- Cambrian rhyolites.
3. At Bryn-mawr—Pre-Cambrian rhyolites and tufts.
Pre-Camprran Rayotrres ano ‘T'urrs.—l'o sum up, the solid rocks
exposed in the area between Cil-y-Coed and the village of Pen-y-groes
comprise a volcanic series of rhyolitic type, probably Pre-Cambrian,
overlain by a series of conglomerates, grits, and slates of Lower
Cambrian age. This sequence represents substantially the succession
which obtains in the main portion of the St. Annes—Llanllyfni ridge
to the north-east ; and it is clear that the solid rocks of the St. Annes—
Llanllyfni ridge extend at least 3 miles further south-west than is
represented in the Geological Survey Map.
In conclusion, I desire to express my indebtedness to Mr. C. J.
Edwards for suggesting the work on Cil-y-Coed and for several
photographs, to Dr. Cox for reading through the manuscripts and for
various suggestions during the course of the investigation, and to
Dr. Gordon for his help in connexion with the microphotographs.
REVIEBwWwS-
I.—Tur Grocrapay and Geronrocy or West-Cenrran Sryar. By
Joun Batt, Ph.D., D.Sc., F.G.8., A.R.S.M., Mem. Inst. C.E.
pp. ix, 219, with two geological maps printed in colour,
22 plates, and 54 text-figures. Cairo: Government Press, 1916.
Price 30 P.T.
fW\HIS important work owes its origin to the discovery of ores of
manganese and iron in the Sinai Peninsula by the late
Mr. Thomas Barron during his reconnaissance survey of a vast area
in Western Sinai in the years 1898-9. Prospecting followed, the
Sinai Mining Co. was formed to exploit the deposits, and Dr. Ball
was deputed by the Director of the Geological Survey of Egypt to
Geology of West-Central Sinai. 81
earry out a detailed topographical and geological survey of the area
in which the more important deposits occur. He has produced an
accurate map of an area of 3880 square miles limited by the parallels
of 29° 15’ and 28° 56 20" N. lat. and by the meridians of 32° 9’ 35”
and 838° 27' 380” KE. long. on a scale of 1:50,000, on which the
distribution of the various geological formations, ranging from the
granite and gneiss of pre-Carboniferous age through the Carboniferous,
Cretaceous, and Tertiary to the Pleistocene and Recent deposits of
alluvium and blown sand, is laid down. ‘The topographical and
geological details were recorded simultaneously, and as an illustration
of Dr. Ball’s skill and neatness as a surveyor it may be mentioned
that the maps are based on direct photographic reproductions of the
field-sheets. In addition to the general map, the work is illustrated
by a larger scale map (1: 25,000) of the environs of Um Bogma,
where the chief mines are situated, a plate of sections, numerous
photographs, and a large number of text-figures, including pen-and-
ink sketches of the most typical fossils drawn by the author from
actual specimens.
After describing the general features of the district, which consist
of highly dissected tablelands and assemblages of rugged granitic
peaks, with occasional more open areas, the author gives an account
of the survey operations, of the methods adopted in laying out the
base-line, in determining its geographical position, and in connecting
up the triangulation with that of Egypt proper. ‘Then follow
chapters dealing with the topographical features—the wadis, the
mountains and the plains—and with the geology.
In the centre of the area lies a broad sandy plain at a height of
about 500 metres above sea-level, on which the base-line was laid
down. This is bounded on the north by the formidable escarpment
of Gebel el Tih, the edge of which is from 500 to 600 metres above
the plain and extends from east to west in a somewhat sinuous curve.
The base of the escarpment is formed of Nubian Sandstone, then
follow 200 metres of fossiliferous Cenomanian clays, marls and lime-
stones, which are capped by beds of Turonian limestone. The
escarpment forms the southern termination of a deeply dissected
plateau which stretches far to the north, and it is a remarkable fact
that although the valleys descend rapidly from the edge in that
direction, none appears to have been beheaded by the recession of the
escarpment. Many points on the edge have been accurately fixed.
South of the central plain is a wild country with only relics of
plateau structure, in which many mountains rise to heights of 700 or
800 metres above the sea and one to over 1 ,000 metres. It consists
of the pre-Carboniferous complex of eranite and metamorphic rocks,
on the planed-down surface of which rest strata of Carboniferous age.
The time available did not admit of any attempt to separate the rocks
of the complex, which is presumably Archean. The Carboniferous
rocks consist of a lower sandstone (130),! a middle limestone with
fossils, similar to those occurring in Derbyshire and Yorkshire (40), and
an upper sandstone with ZLepidodendron (130). To the west of the
central plain this upper sandstone underlies the Nubian Sandstone,
1 The figures in parentheses represent thicknesses in metres.
DECADE VI.—VOL. IV.—NO. I. 6
82 Reviews—Dr. John Ball—
which it closely resembles. This point is one of great interest on
account of the discussion which has taken place as to the age of the
Nubian Sandstone. In the region we are considering the vast period
of time separating the Carboniferous Limestone from the marine
Cenomanian clays is represented by 650 metres of sandstone, which
are conformable to the rocks below and above, and in which no break
can be detected. Dr. Ball separates the lower portion of this series
(130) under the name of Upper Carboniferous Sandstone, on account
of the occurrence of fossils of the Lepzdodendron type, from the upper
portion (500) to-which he restricts the name of Nubian Sandstone.
The only traces of fossils found in the upper portion are a piece of
silicified wood ‘‘ similar to that which occurs in the Nubian Sandstone
of Egypt’’, and a thin layer of very impure coal. Owing to the
discovery of Jnoceramus in the Nubian Sandstone of Aswan and the
intercalation of the sandstone with the overlying marine Cretaceous
in other parts of Egypt this formation is now generally regarded as
being of Cretaceous age. Until quite recently no trace of marine
fossils of Triassic or Jurassic age has been found either in Egypt or
Sinai, but Dr. Ball refers to a discovery of Jurassic deposits in the
northern portion of the peninsula, and suggests that part of the
Nubian Sandstone may be of the same age. Details of this important
discovery do not appear to have been made public.
So far we have been referring to about three-fourths of the area
covered by the map. This portion is bounded on the west by a series
of important faults following a general direction a little east of
south, roughly parallel to and at an average distance of about ten
kilometres from the Gulf of Suez. The remaining portion consists
principally of Campanian strata, but contains also representatives of
the Eocene and Miocene periods. At one point Miocene rocks are
faulted against the Lower Carboniferous Sandstone, and the throw is
estimated at probably not much less than 2,000 metres. The
faulting is regarded by the author as belonging to the close of the
Miocene period; but the possibility of its having commenced at an
earlier period must not be overlooked.
Campanian strata (300?) form a highly dissected hilly country of
a dazzling white aspect. Eocene strata appear to rest conformably
on the Campanian. They are much thinner than those on the
opposite side of the Gulf of Suez and in the Nile Valley. The
Miocene rocks occur in detached patches and comprise conglomerates,
gritty limestones, clays, and chalky rocks often impossible to
distinguish from Eocene or Cretaceous in the absence of fossils. The
author sums up his observations on the Miocene deposits in this part
of Sinai by saying that ‘‘ the more easterly portions are characterized
by great accumulations of conglomerates and grits, indicating that
the old shore ran approximately along the line of the great fault
already referred to, while farther to the west there is increasing
predominance of limestones, clays, marls, and gypsum, indicating
deeper water conditions for certain beds”’.
The geological history of Egypt during post-Hocene times is of
great interest, but it is difficult to correlate the available information.
The prolonged hydrocratie movement which lasted during the
3
.
{
i
Geology of West-Central Sinar. 83
Cretaceous and Eocene periods was followed by a geocratic movement
in Oligocene times, when the fluvio-marine beds of the Fayum were
formed with the remarkable deposits containing mammalian remains
at their base. To this succeeded another hydrocratic movement in
Miocene times. Miocene deposits occur in northern Egypt, on the
borders of the Gulf of Suez, and in the neighbourhood of Ras
Mohammed. ‘They occur at different levels and sometimes have the
character of beach deposits. Did the earlier Miocene deposits
advance over a planed down surface of older rocks? ‘This is
suggested by Dr. Ball’s work, for it is impossible to avoid the
conclusion that the Cretaceous and Eocene deposits once extended
over the whole area. Moreover, a small patch of Miocene strata,
wedged in between two faults just north of Gebel Sarbut el Gamal,
is represented on the map as resting both on Nubian Sandstone and
on Cenomanian, whereas Miocene rests on Campanian, without
any intervention of Eocene on the mountain itself, of which it forms
the summit. .
As evidence of the great differences of level at which Miocene
rocks occur, it may be pointed out that the boring for oil at Gebel
Zeit! ended at a depth of about 1,100 metres below sea-level in
rocks which are supposed to be of Miocene age, whereas the top of
Gebel Sarbut el Gamal is 642 metres above the sea, making
a difference of 1,742 metres. How far these differences of level are
to be accounted for by deposition at different times while geographical
evolution was going on, and how far they are due to movements of
elevation and depression affecting large areas or to faults subsequent
to deposition, cannot be determined with precision at present, but
the last-mentioned cause has certainly played an important part.
Basalt sills and dykes occur at many points in the district. They
are all referred by the author to the Miocene period.
The ores of manganese and iron (pyrolusite, psilomelane, wad,
and hematite) occur at the junction of the Carboniferous Limestone
and the underlying sandstone in certain places. They form irregular
deposits which are only found in the neighbourhood of faults and
become thicker and richer as the faults are approached. Where they
occur certain dolomitic limestones, containing small amounts of
manganese and iron, have partially or wholly disappeared, and it is
suggested that the circulation of water along the fault fissures has
removed the carbonates of lime and magnesia from the limestones
and left behind the manganese and iron as oxides. The principal
objection to this theory is that the amount of manganese in the
dolomites which have been analysed is very small—less than 3 per
cent. Is it possible that beds much richer in carbonate of
manganese, like those occurring in Merionethshire, are present but
not exposed ?
In these days, hes. there is a marked recrudescence of old
superstitions, not confined to geology, it is interesting to note that
Dr. Ball, so far as this district is concerned, attributes the surface
inequalities directly to erosion. After pointing out that valleys
_] Explanatory notes to accompany the Geological Map of Egypt by W. F.
Hume, Cairo, 1912.
84 Reviews—Prof. C. Schuchert’s Text-Book of Geology.
sometimes coincide with faults he says: ‘‘It is important to note
that the same fault which coincides with a deeply eroded wadi along
one part of its course may cut across a high mountain tract in
another part, and frequently at the latter place there is not the
slightest change in the contour of the surface to mark the line of
fault. ‘Nothing of the nature of a ‘rift’ is anywhere visible;
faults have governed the position of drainage lines in places, but
erosion alone has removed the material from the valleys.’ In
_discussing the relation of the faults to the Gulf of Suez, which has
been regarded as a trough subsidence, he refers to his papers in the
Gnotogican Magazine! in which he has brought forward arguments
in favour of the view that it is a submerged land valley.
Enough has been said to show that this clearly written, beautifully
illustrated, and well-printed monograph is an important contribution
to our knowledge of the geography and geology of the Simai
peninsula.—J. J. H. T.
IJ.—A Texr-Book or Gronogy. Part Il: Hisrortcan Guronoey.
By Cuartes Scnucner?. pp. vill + 405-1026, xxxyii plates
printed in text, text-figures 312-522, and Geological Map of
North America. New York, John Wiley & Sons, Inc.; London,
Chapman & Hall, Ltd. 1915. Price 12s. nett.
INHE first part of this text-book, dealing with Physical Geology,
was reviewed in the Guotocicat Macazrne for September, 1916.
Physical Geology is much the same the world over, though certain
aspects may be more studied, or certain theories more favoured, in
one country than in another. Historical Geology on the other hand,
unless it be treated from the view-point of that observer in space
whom Suess imagined, almost inevitably takes its colouring from the
native country of the historian. This tendency is accentuated, and
naturally so, when the exposition is based on lectures to the students
of a single university. Above all is the difference marked between
an American and a European treatment of the subject. We are
therefore not surprised. to find in Professor Schuchert’s book,
embodying as it does a course delivered to undergraduates of Yale,
a presentation of historical, or at any rate of stratigraphical, geology,
which to one brought up on Sedgwick, Murchison, Geikie, and
Prestwich, might almost seem to be the account of another world.
We do indeed find such familiar names as Cambrian, Carboniferous,
and Cretaceous (and we must rejoice that Professor Schuchert’s
publishers or his own better judgment have not permitted him to —
_use the Cambric, Carbonic, and Cretacic, which he has long sought
to introduce ); but even these household words have a novel content.
The name Carboniferous has long been restricted by American
geologists to the equivalent of our Coal-measures. Then this gave
place to ‘‘Pennsylvanian’’, the Lower Carboniferous becoming
‘¢ Mississippian ’’; and now the latter is split into an upper system,
the ‘‘Tennesseian’”’, including all formations from the Kaskaskia
1 “Origin of the Nile Valley and the Gulf of Suez,’’ Gnon. MaG., 1910,
p. 71, and ‘‘ The Gulf of Suez’’, Gkou. MAG., 1911, p. 1.
Reviews—Prof. C. Schuchert’s Text-Book of Geology. 85
down to the Warsaw, and a lower ‘‘ Waverlian”’, continuing from
the Keokuk to the unfamiliar Chattanooga. These rather uncom-
tortable system-names are adopted from Mr. E. O. Ulmch, who,
however, spelt them differently. In similar fashion the name
“Cretaceous” is restricted by Mr. Schuchert to formations corre-
sponding to our Upper Cretaceous, i.e. down to the beginning of
Cenomanian time; the preceding ages, from Albian to Neocomian
inclusive, are erected into the Comanchian period, at least so far as
North America is concerned.
It may be gathered from the preceding paragraph that, except for
the Eras, and to an incomplete extent for the Epochs, Professor
Schuchert does not attempt to overcome the difficulties inherent in
geographical treatment by any use of universal 'Time-names. For
him such ages as ‘ Tournaician ’ [see] or ‘Cénomanian ’ [s?c] are just
as local as ‘the Elizabethan period or the Carlovingian epoch. No
living geologist is better fitted to discuss questions of correlation, at
all events for the Palaeozoic era, than is Professor Schuchert, and
the fact that ke is deliberately provincial may be held to indicate
that in his opinion the time is even yet not ripe for comparison of
the isolated histories with any universal Time-standard. Such an
opinion does not well harmonize with the widely held view that
the rhythmical movements of the earth’s crust are at the base
of the whole march of the world and its varying tempo, or with
the knowledge we already have of those movements—a knowledge
so well illustrated by Professor Schuchert’s numerous maps, and
emphasized by the varied names that he provides for uplufts and
disturbances, such as the delightfully christened Shickshockian.
No doubt, as he says, we have still much to learn in Europe as in
America; and the more we know the more impossible will be exact
correlation of far distant strata. But the practical application of
a Time-scale will always help us over many difficulties, and will at
least show just where our knowledge is defective.
The book is meant to be a guide for American students, and for
‘such a purpose it seems well adapted. Apparently the students of
geology at Yale are not expected to have any knowledge of
- elementary zoology and botany, and so the lecturer has ever and
anon to break the thread of his discourse in order to impart
information concerning the anatomy of Mollusca, the origin of
lungs, the classification of Pteridophyta, the physiology of
Amphibia, ampiotic development, human embryology, and other
matters properly belonging to other branches of study. However
well Professor Schuchert deals with these subjects, the space devoted
to them has necessarily to be taken away from stratigraphical
geology, and the part that suffers is, as already indicated, the
history of other countries. For us on this side of the Atlantic,
therefore, the book must serve, not as a text-book for our
students, but as a useful conspectus of American geological history.
Here the rapid advance has of late introduced so many changes that
one is grateful for a handy volume in which to follow the succession
of geographical forms, and from which to extract the meaning of
Appalachicola, Arikaree, Swearinger, Bertie, Cannonball, Kittatinny,
86 Reviews—O. C. Farrington’s Meteorites.
and Mauch Chunk. One must also be grateful for some admirably
written sections on the beginnings of earth-history by Professor
Barrell, and for a well-illustrated chapter on Dinosaurs by Professor
Rk. 5S. Lull. In brief, this is an original and stimulating book,
where fact and theory are happily mingled, and the tangled threads
of many complicated series of events reduced to an orderly and
attractive pattern.
I{1.—Merrorrres: rHeir Structure, Composrrion, AND TERRESTRIAL
Retations. By O. C. Farrrneton. pp. x, 233, with frontispiece
and 65 figures in text. Chicago: published by author, 1915.
Price 8s. 6d.
fJ\HE absence of a comprehensive and up-to-date book on meteorites
has undoubtedly been a factor in confining the interest in this
subject to a comparatively small number of geologists. he admirable
introduction to this study in the handbook to the collection in the
Natural History Museum is of course limited in scope, while Cohen’s
Meteor itenkunde, which was intended to cover the full ground of the
subject, was unfortunately little more than half finished at the
author’s death. Dr. Farrington’s book, therefore, fills a gap in
scientific literature and will be indispensable to the student who
desires a general knowledge of the subject.
The book opens with a discussion of the criteria whereby meteorites
may be distinguished from terrestrial material, and emphasis is laid on
the superficial and chemical characteristics by which the former may
be discriminated when, as is generally the case, the fall has not been
observed. Several chapters are devoted to the fall of meteorites,
while the succeeding sections are concerned with the form and size of
these bodies. As is to be expected, the discussion of the composition
and structures is very full, the explanation of the octahedral structure
so common in ‘irons’ and the account of the structures found in
‘stones’ being admirably lucid. In the description of the mineral
species a large amount of space is devoted to the three types of nickel-
iron, but this constitutes the least satisfactory portion of the book.
Thus plessite is explained by analogy with the system silver-copper,
as a eutectic developing probably from solid solution, but no mention
is made of the recent metallographic work on the system iron-nickel.'
‘The investigations of Osmond and Cartaud, Tammann, and particularly
Ruer have shown that y-iron and #-nickel are isomorphous and that
this solid solution on cooling undergoes a number of changes in the
solid state. a-iron and a-nickel, the low-temperature forms, also
give solid solutions, and kamacite is to be regarded as a nearly saturated
solid solution of a-nickel and a-iron, and not, as Dr. Farrington hints,
as a compound of constant composition, Ni Feyy. The only compound
in the system has the composition Fe Ni, and tanite is considered to
be a solid solution of a-iron and this compound, while plessite is
a eutectoid of kamacite and tenite, separating from solid solution.
' A useful summary of this is given by Desch, Metallography, 2nd ed., 1913,
pp- 383-5.
ae
:
|
|
ee a ee
Reviews—H. J effreys Radvoactivity. 87
The author uses Rinne’s term ‘eutropic’ in place of ‘eutectoid’, but
this is inadvisable as ‘eutropic’ had previously been used in another
crystallographic sense by Linck in 1896, while ‘eutectoid’, first
suggested by Howe in 1908, has also priority over ‘eutropic’
(suggested by Rinne in 1905) and has been generally adopted.
_ For a long time the structure of meteorites was regarded as
metastable, as it could be destroyed by annealing and a granular
texture—occasionally found naturally—obtained. Recently, however,
Benedicks, by very slow cooling, has obtained plessite and reproduced
the octahedral structure. Hence the granular structure is to be
regarded as metastable, and the difficulty in reproducing the usual
meteoric structure is to be ascribed to the low rate of diffusion
inhibiting changes in the solid state. ;
In tie chapter on classification the only system given is Brezina’s
modification of the Rose-T'schermak classification. It would have
added to the interest of the book if the author had given his own
interesting classification based on the American quantitative system
for igneous rocks, and Berwerth’s rational system founded on the
synthetic work on nickel-iron. The recent genetic one, devised by
Prior, was, of course, published after this book appeared.
The illustrations are excellent and the letterpress very clear,
though there is a misprint in figure 53 and another on p. 189. The
use of such a contraction as ‘A.N.H. Wien’ is by no means clear.
Nevertheless the book can be confidently recommended as the best
general introduction to the study of meteorites which has yet
appeared, and should be in the possession of everyone interested in
the subject.
pau ALIS):
LV.—Raproactivity AND Mounvrarn Boinpine.
Tux Compression or THE EKartH’s Crusr 1x Coomne. By Harorp
_Jerrreys. Phil. Mag., xxxul, pp. 575-91, December, 1916.
f{VHE view that mountain-building owes its principal cause to the
contraction of the earth has been widely adopted by geologists.
‘The subsidiary view that the alleged contraction is due to loss of heat
has not met with equal success. The calculations of T. Mellard Reade,
made before the discovery of radioactivity, indicated that the cireum-
ferential shortening of the globe (in cooling from a molten state to its
present condition during a period of 100 million years) could not
exceed 10°5 miles. ‘his figure is only a small percentage of the
shortening implied by the existence of great mountain ranges.
Moreover, various calculations of the Jevel of no strain by Fisher,
Reade, Davison, and G. H. Darwin gave results varying between
0:7 and 7:8 miles. ‘That is to say, compressional deformations of the
earth’s crust must, on the older hypotheses, have been limited to
a thin superficial shell which could never have accumulated the
enormous stresses required for periodic mountain-building. ‘Thus, in
two directions, the thermal’ contraction theory was shown tv be
hopelessly inadequate to meet the facts. Consequently other causes
of contraction have come to be invoked in recent years; among them,
88 Reviews—Mineral Resources of the United States. —
a molecular rearrangement of compounds in the earth’s interior,
which under high pressure may be supposed to involve a decrease in
volume.
With the discovery of radioactivity and the realization of its
fundamental importance in dynamical geology it became evident that
the thermal contraction theory stood in urgent need of re-examination.
The mathematical skill required for this task is of an order far beyond.
the attainments of most geologists, and Mr. Harold Jeffreys has come
to our assistance by working out, in the light of our later knowledge,
the group of problems involved. Using the thermal and radioactive
data adopted by the present writer in a series of papers which have
appeared in the pages of this Magazine, he has arrived at the following
results :—
(a) The level of no strain is now at a depth of 79 km. (uniform
distribution of radioactivity) or of 76 km. (exponential distribution).
(6) Every great circle of the earth has been shortened by 227 km.
(uniform distribution of radioactivity) or by 133km. (exponential
distribution). ‘To arrive at the radial shortening, these figures should
be divided by 6°28.
(c) The surface of the earth has been diminished by crumpling by
56 X 10° sq. km. (uniform distribution of radioactivity) or by
3°3 X 10° sq. km. (exponential distribution).
In order to test these results Mr. Jeffreys has calculated from the
mean height of existing mountain ranges the approximate diminution
of the surface by crumpling. He finds the amount to be about
1:8 X 10° sq. km., which is little more than half of the amount
implied by the thermal contraction hypothesis in its new form
(exponential distribution). It should be pointed out, however, that
Mr. Jeffreys’ calculation of the actual amount of diminution of the
surface by crumpling gives only a minimum result, for it does not
take into consideration the former existence of ranges that are now
submerged or denuded to insignificant elevations. Most of the ranges
measured are of post-Carboniferous age, and may therefore represent
only a third or a quarter of the total crumpling since geological
history began. The maximum circumferential shortening demanded
by Chamberlin is about 3800 km., corresponding to a surface
diminution by crumpling of 7-6 x 10° sq. km., more than twice as
much as that found theoretically on an exponential distribution of
radioactivity. Nevertheless, in spite of the fact that complete
accordance has not yet been attained, itis evident that the theoretical
and observed compressions are of the same order of magnitude, and it
may confidently be asserted that the much abused thermal contraction
hypothesis, thanks to radioactivity, has now been set firmly on
its feet.
’Arravur Hommes.
V.—Minerat Resources of THE Unirep Srares For 1914.
(TVHIS is the 33rd of the admirable series of reports which was
started in the early years of the United States Geological
Survey. Year by year they give carefully prepared statistical
—aee eo
Reports & Proceedings—Geological Society of London. 89
information of the output of minerals in the country and of the
imports from outside. As usual this report is divided into two main
parts, of which the first deals with metallic and the second with
non-metallic, substances, the latter including fuels, structural
materials (other than metals), chemical minerals, and precious
stones. Each chapter is entrusted to a different writer, and each
is issued separately as soon as it isready. ‘The date of publication
of the several chapters is given on the wrappers, but disappears in
the bound-up volume ; the pagination is continuous, but separate
throughout each part of the report, including the summary. The
series is so well known that detailed criticism is uncalled for; it is
sufficient to say that the present report is well up to the high
standard of its predecessors.
REPORTS AND PROCHHDINGS.-
$< —
I.—GeroLtocicaL Soctery or Lonpon.
1. December 20, 1916.—Dr. Alfred Harker, F.R.S., President,
in the Chair.
Marie C. Stopes, D.Sc., Ph.D., gave an account of some recent
researches on Mesozoic ‘ Cycads’ (Bennettitales), dealing particularly
with recently discovered petrified remains which reveal their cellular
tissues in microscopic preparations. To make the significance of the
various fossil forms clear, Dr. Stopes first showed some lantern-slides
of living Cycads, and then pointed out that it was in their external
features and in their vegetative anatomy only that the fossil ‘Cycads’
-were like the living forms; the most important features, the repro-
ductive organs, differ profoundly in the two groups, and the fossils
were fundamentally distinct, not only from the living Cycads, but
from all other living or fossil families.
The fossils representing the group that are most frequently found
are (@) trunks, generally more or less imperfect casts or partial
petrifactions, and sometimes excellent petrifactions preserving
anatomical details and cell-tissues; (6) impressions of the foliage.
Not infrequent are the detached impressions of incomplete ‘flowers’
_ or cones, of one cohort (the Williamsone), while petrified fructi-
fications are numerous in some of the well-petrified trunks of the
Bennettitee. The described species of the group run into hundreds,
but probably many of these duplicate real species, because the foliage,
trunks, pith-casts, various portions of the fructifications, ete., have
often been separately found and named. In very few cases have the
different parts been correlated. The species of the foliage are the
most generally known, as they are the most readily recognized with
the naked eye; they have been described under a variety of generic
names,
The following table gives the proved, or probable, associated parts
of some members of the group :—
90 Reports & Proceedings—Geological Society of London.
FOLIAGE. TRUNK. FRUCTIFICATIONS.
Zamites spp. Bennettites spp. Bennettites spp.
Zamites gigas. Attached, no separate Weallaamsonia gigas.
: name.
Otozaniites sp. = Williamsonia spectabilis.
Ptilophyllum pectinoides. = Williamsonia whitbiensis.
Anomozamites mmor. (Only slender branches Wielandiella angustifolia.
known, no name.)
Teniopteris vittata. — Williamsoniella coronata.
Dr. Stopes exhibited slides of microphotographs of the stem and
leaf-base anatomy of the group, including some unpublished details
of Bennettites maximus. The roots of the group have hitherto been
entirely unknown, and a slide was exhibited for the first time showing
rootlets penetrating the leaf-bases of a petrified specimen (represented
by a section in the Geological Department of the British Museum—
Natural History). These roots probably belong to B. sawbyanus :
they are covered with wonderfully petrified root-hairs, running
uncollapsed through the silica matrix. They raise interesting
questions concerning the possible chemical conditions of the infiltra-
tion of the silica. Illustrations were also exhibited of the famous
complex ‘flower’ and cone-structures, and of Wieland’s brilliant
restorations of the same. Microphotographic slides were exhibited
of the seed-cone of an interesting unpublished new species from the
British Gault. This is beautifully petrified, and adds to our know-
ledge of the finer anatomy of the seeds and associated structures. It
is also the largest cone of the Bennettitales yet known, though it
occurs in the Gault, by which time the group appears to have begun
rapidly to die out.
The following table indicates the distribution of a few of the most
interesting representatives of the Bennettitales (including the cohorts
Bennettites and Williamsonez) :—
UppER CRETACEOUS. Very fragmentary and uncertain records; apparently
the group is nearly or quite extinct.
MIDDLE CRETACEOUS : The new large-sized seed-cone.
Gault. B.morverei 2 (? described originally from the J urassic).
LOWER CRETACEOUS: Well-petrified trunks with fructifications.
Lower Greensand. 2B. gibsonianus (type-species of the Bennettitex).
Potton Sands.
Wealden.
JURASSIC: Purbeck.
B. maximus.
Trunks, e.g. Colymbetes edwardsi.
Trunks (casts and petrifactions),
foliage.
B. saxbyanus.
Trunks (casts and semi-petrifac-
tions).
Buckland’s original Cycadeoidea
Throughout these
periods in ©
America, trunk-
remains very ;
abundant, often
petrified and with
fructifications,
particularly from
spp. the Black Hills,
C. gigantea. : South Dakota,
Oolites. Trunks, pith-casts, etc. Much}and Maryland.
foliage of various types. Wil-| C. jenneyana,
liamsonia gigas and other fruit-| C. mgens, C.
impressions. wielandt, ete.
W. scotica.
Williamsoniella coronata. | Richimpressionsin Mexico
Lias. Foliage and Williamsonia of Williamsonia and many
fruits (India). Wicchiaceecacrs
Rhetic. Wielandiella angustifolia and foliage.
|
Reports & Proceedings—Geological Society of London. 91
The group is by far the most characteristic of all the plants of the
Jurassic and Lower Cretaceous, during which periods its distribution
was almost world-wide. It was locally, if not universally, dominant,
and was the most highly evolved plant-group of the epoch of which
we are cognizant.
Three chief points of interest are to be noted in the geological
distribution of these plants: ~ (a) that the most numerous highly
specialized trunks reach their maximum in the Jurassic and Lower
Cretaceous Periods, when their distribution was practically world-
wide ; (4) that the oldest and therefore presumably the most primitive
type, Wielandiella, is externally less like the living Cycads than the
commoner later forms, while these latter are utterly unlike the living
genera in their fructifications; (¢) that the geologically youngest
cone is the largest yet discovered, occurring in the Gault when the
extinction of the group appears already to have set in.
Contrary to what might have been anticipated from their external
likeness to the living Cycads, coupled with their great geological age,
the fossil ‘ Cyeads’ are much more complex and on a higher level of
evolution than the living group. It seems to the author to be
extremely unlikely that the fossil and the living forms have any
direct phylogenetic connexion nearer than a remote, unknown,
commonancestor. The mooted connexion between the fossil ‘ Cycads’
and the Angiosperms is highly suggestive, but lacks data for its
establishment.
A short discussion followed, and the thanks of the Fellows present
were accorded to Dr. Stopes for her lecture.
2. January 10, 1917.—Dr. Alfred Harker, F'.R.S., President, in the
Chair.
ee following communications were read :—
On the Paleozoic Platform between the London Basin and
esau Areas, and on the Disposition of the Mesozoic Strata upon
it.” By Herbert Arthur Baker, BSc., F.G.S. With an Appendix
by Arthur Morley Davies, D.Sc., F.G.S.
The author carries on the work of Dr. A. Strahan and Dr. Morley
Davies in tracing the contours of the Paleozoic platform of the
South-East of England. By comparing these with the contours of
the base of the Gault, he determines the probable boundaries of the
areas -of the platform that were only submerged finally under the
Gault sea. He analyses the effects of post-Cretaceous tilting and
warping, and presents a map illustrating the contours of the Palzo-
zoic floor at the end of the Lower Cretaceous Period.
He next discusses the successive Mesozoic overlaps on the platform,
the probable areas that they respectively cover, and the relation of
these to the tectonics of the platform itself. He claims that there
is evidence for a second Charnian axis, parallel to that traced by
Professor P. F. Kendall, proceeding south- eastwards through Norfolk
and Suffolk, east of Kent, to the North of France. He further
suggests that the area between these two geo-anticlines is a geo-
syneline, which in Mesozoic times, in consequence of the accumulation
92 Reports & Proceedings—Geological Society of London.
of sediments within it, and the continued operation of Charnian
movement, became converted into an anticline (as in the case of the
‘Wealden area).
In an Appendix, Dr. Morley Davies discusses the interpretation
of the Saffron Walden boring, and its bearing on the supposed inter-
Charnian trough; he also points out evidence of a post-Cretaceous
Charnian anticline under London.
2. ‘‘ Balston Expedition to Peru: Report on Graptolites collected
by Captain J. A. Douglas, R.E., F.G.8.” By Charles Lapworth,
LL.D., M.Sc., F.R.S., F.G.S.
The specimens of graptolites were collected from the rocks of the
Inambari district in Peru by Captain Douglas, under whose. name
the collection has been placed in the Geological Department of the
University Museum, Oxford. These fossils were forwarded by
Professor W. J. Sollas to Professor C. Lapworth, who embodied the
results of his study in a Report, of which the following is a brief
abstract.
The specimens are recorded as all occurring in the same locality,
but it is not known whether they were obtained from a single zone.
The majority of the rock-specimens in which the graptolites occur
are black and somewhat pyritous carbonaceous shales, usually well
bedded and uncleaved, and the graptolites are in general well
preserved. The lithology of the containing rocks and the mode of
preservation of the graptolites are similar to those obtaining in the
richest graptolite-bearing strata of Britain, Europe, and North
America.
The forms apparently represented in the collection are Logano-
graptus logani, Hall, a new species of Goniograptus (?), Didymograptus
stabilis, Elles & Wood, and D. bifidus, Hall, Phyllograptus angusti-
folius, Hall, Glossograptus acanthus, Elles & Wood, Cryptograptus
tricornis, Hall, var. Amplexograptus confertus, Lapworth, and
A. celatus, Lapworth.
Taken as a whole this graptolite fauna may best be compared with
that of the Upper Arenig formation of Britain and its North American
equivalents, answering to the Lower Llanvirnian of Hicks & Marr,
and the Didymograptus bifidus zone of Elles & Wood and H.M.
Geological Survey.
The assemblage of graptolites discovered in Bolivia a few years
ago by Dr. J. W. Evans corresponds very closely with this Peruvian
fauna, and was probably derived from the southward continuation
of the same Andean graptolite band. The Peruvian forms in the
Douglas Collection, like those from Bolivia, admit almost as close
a parallelism with those of the Arenig—Llandeilo graptolite beds of
Australia and New Zealand as with their representatives in the
Northern Hemisphere.
Not only is the Douglas Collection of Peruvian graptolites
instructive and valuable from the paleontological point of view,
owing to the number and good state of preservation of the species
represented, but it is of especial interest from the paleeographical
aspect, as affording additional proof of the identity (in general facies)
of the graptolite fauna of the sea-waters of Lower Ordovician times
Reports & Proceedings—Edinburgh Geological Society. 93
in those regions of the globe which are now occupied by some of the
dry lands of Britain, Eastern North America, Peru, Bolivia, Victoria,
and New Zealand. Thus it greatly strengthens the inference that
in Arenig—Llandeilo times there was open-sea communication
admitting of the circulation of sea currents along some as yet un-
determined line or lines, connecting the above-mentioned regions, which
must have extended across the Equator and apparently throughout
a length nearly equal to that of half the circumference of the globe.
II.—Epinsurce GroLiocicaL Socrery.
December 20, 1916.—Dr. Flett, F.R.S., President, in the Chair.
The following papers were read :—
1. ‘‘Igneous Intrusive Phenomena at Upper Whitfield, near
Macbiehill; and at Raveirig and Kaimes Hill Quarries, Balerno.”’
By T. Cuthbert Day, F.C.S.
- The intrusive nature of the Upper Whitfield hasalt was established
by the discovery of upper and lower contacts with the sedimentary
deposits. Jetails of a xenolithic structure in the igneous rock at the
point of contact were given, and a peculiar marmorized dolomite
associated with chert was described. Mention was also made of
a case of metasomatism in basalt through the action of a deposit of
dolomitized calcite.
A description was given of a peculiar tachylite in connexion with
the intrusive olivine dolerite at Ravelrig and Kaimes Hill quarries,
Balerno.
_ 2. “Ona Section in a Bore-hole in the Calciferous Sandstones,
Upper Old Red Sandstones, and Lower Old Red Sandstone Lavas in
the Grange District, Edinburgh.” By D. Tait, H.M. Geological
Survey.
Mr. Tait said that the geological horizon of the beds in the upper
_ part of the bore are on the boundary between the Carboniferous and
the Old Red Sandstone formations, but, as no fossils had been found
in the bore, no sharp line could be drawn at their point of junction ;
possibly they form passage beds between them, since there were
present, interbedded with each other, beds typical of both formations.
At a depth of 284 feet a fault breccia was passed through. This
probably indicates a fault, with a downthrow to the south-west, but
its importance is not known. From 389 to 397 feet cornstone bands
and nodules were found, interbedded with red marly clay. At
399 feet the bore passed through the unconformity between the Upper
Old Red Sandstone and the Lower Old Red Sandstone. The Lower
Old Red Sandstone rocks are lavas of Blackford Hill Quarry type .
and a bed, 47 feet thick, of volcanic agglomerate. The total depth
of the bore from the surface was 475 ft. 6 in.
Ill.—Tur GerotocicaL Sociery oF Giasgow.
At a meeting of the Geological Society of Glasgow held on
December 14, 1916, Mr. H. R. J. Conacher read a paper on ‘‘ Oil-
shales and Torbanites”’. The rocks of these types which occur in
94 Reports & Proceedings—Geological Society of Glasgow. — ¥
the Lothians yield, on destructive distillation, a characteristic crude
oil which consists chiefly of paraffins, olefines, and naphthenes. and
they thereby differ from ordinary coals, the liquid products of which
contain but small amounts of these hydrocarbons. This peculiarity
has been variously ascribed to the presence of vegetable matter
derived from alge or higher plants in a more or less decomposed
state, animal matter from the fish, ostracods, etc., whose remains
are abundant in the shales, to the presence of petroleum or other
bituminous substances or to a hypothetical material called kerogen.
The author described a series of experiments undertaken with a view
to attaining a definite result, the method being to ascertain what
material could actually be detected by means of the microscope, and
to compare these constituents with the results of the distillation of
the same samples.
In those shales which contain animal remains, the yield and
quality of oil is independent of the amount of animal remains, but
varies in proportion to the quantity and nature of the vegetable
matter present. The latter consists of two distinct types. One
portion seems to be macerated and carbonized plant-material, similar
to that of which coal is composed, while the other portion is
_composed of certain yellow bodies which have been variously
described as spores, fossil alge, or globules of dried-up petroleum.
It is these yellow bodies which yield the distillation products of oil-
shales and torbanites. The evidence is against these bodies being
spores, alge, or petroleum, and it is shown that they are simply
fragments of resin set free by the decay and oxidation of woody
matter with which they had been originally associated, and that, by
the physical action of pressure and shrinkage, structures had been
developed simulating those of spores and alge. The failure to
obtain appreciable amounts of extract by means of the usual solvents
is inconclusive, as it is known that the solubility of resins rapidly
diminishes with increasing age. Further it has recently been found
that the resinous material extracted from coal yields on distillation
just such products as are got from oil-shales and torbanites. The
author’s view, therefore, is that both oil-shales and torbanites are
derived from the same original materials as ordinary coals, but have
reached a state of more complete elimination of the perishable parts,
leaving the resins with a proportion of material derived from the
decomposition of the woody substances, which in the case of oil-
shales are mixed with a large proportion of mud.
Mr. J. Neilson read a paper entitled ‘‘ The Auld Wives’ Lifts, an
Ancient Monument”’. He objected to the view that these stones had
reached their present position through natural agencies by the
subaérial weathering of a ridge, as the position of the stones in the
centre of a shallow amphitheatre rendered the action of erosion
negligible, while the surrounding rocks show little sign of alteration
since Glacial times. The theory that their origin is due to ice-action
is equally untenable, while there are likewise difficulties in the
hypothesis that the structure is a ‘‘tor’’. The explanation advanced
by the author is that the “ Lifts”’ did not attain their present position
by natural agencies, but that they were placed there by man, the
Correspondence—J. W. Gregory. 95
blocks having been taken from the nearest escarpment. The whole
structure belongs to the type of monument known as cromlech or
dolmen, and the irregular form and small dimensions are probably to
be explained by the fact that the chief consideration was the feat of
raising the enormous blocks, the utility of the chamber beneath being
of secondary importance.
CORRESPONDEHNC#E.
PROFESSOR LOEWINSON-LESSING.?
Srr,—It was arranged in January, 1914, that a German translation
of Professor Loewinson-Lessing’s important memoir on the volcanoes
of the central Caucasus should be published in T'schermaks
Mitteilungen. Owing to the strike of the printers in Vienna the
publication of the memoir was delayed till the summer, and before
its issue war was declared. It has subsequently been published, and
Professor Loewinson-Lessing is anxious that it should be understood
by his English friends and fellow-geologists that the publication of
this memoir in Austria was arranged before the War and that he has
since then had no share in its production.
As Professor Loewinson-Lessing has asked me to explain why his
memoir has appeared in an Alien journal during the course of the
War, I shall be much obliged if you would issue this explanation.
J. W. Greeory.
GEOLOGICAL DEPARTMENT, UNIVERSITY, GLASGOW.
January 17, 1917.
(QiSTlAi Slr NAsySse
ERNEST SWAIN.
BoRN JANUARY 15, 1843. DIED DECEMBER 20, 1916.
AurnoucH he never contributed to any scientific publication, Ernest
Swain was well known to a past generation of geologists as a keen
student of the science and a constant attendant at the meetings
of the Geological Society and Geologists’ Association. Of the latter
he remained a member till the last.
He was born at Wood Lane, Shepherd’s Bush, and educated
privately and at King’s College, of which he became an Associate.
His life was passed in business in the West End, but all his spare
time was devoted to scientific studies, and his museum and library
were open to all friends and students, many of whom owed their
start on a scientific career to his influence and aid. He was an
active member of the quondam West London Scientific Association
and the succeeding Western Microscopical Club. He devoted much
time to the compilation of commonplace books, of which he kept
some 140 going on the subjects that interested him. Unhappily he
latterly met with bad times and retired to Chorley Wood, where he
died at the close of last year.
1 Professor of Mineralogy. and Geology in the Polytechnic Institute,
Sosnovka, Petrograd, Russia.
Laat Obituary. :
REGINALD COOKSEY BURTON,
B.Sc., F.G.8., Assistant Superintendent Geological Survey of India.
Born MARCH 10, 1890. DIED OF WOUNDS APRIL 9, 1916.
Tuer name of R. C. Burton has to be added to the ‘‘ Roll of Honour ”
of geologists who have given their lives for their country in the
present War.
Dr. H. H. Hayden, the Director, writes: ‘ ME: Burton joined
the Department in January, 1912, and was posted to the Central
Provinces, where, during his short period of service, he did admirable
work in helping to solve the question of the origin of the calcareous
gneisses which constitute such an important element of the Archean
group of that area. His investigations into the origin of the bauxite
of Seoni and adjoining districts also gave evidence of marked ability,
and by his death the Geological Survey has lost one of the most
promising as well as one of the most popular of its younger members.
Mr. Burton joined the Indian Army Reserve of Officers early in
April, 1915, and after a short training in India was attached to the
104th Rifles in Mesopotamia, where he died on April 9, 1916, from
wounds received in action on the previous day. His loss is keenly
felt by all his colleagues.” (Records of the Geological Survey of
India, vol. xlvii, pt. 111, p. 143, August, 1916.)
SIR EDWARD BURNETT TYLOR, Kn.’
J.P., D.C.L., LL.D., F.R.S., Hon. Fellow of Balliol College, and
Emeritus Professor of Anthropology, University of Oxford.
BORN OCTOBER 2, 1832. DIED JANUARY 2, 1917.
‘'a1s famous Anthropologist was born at Camberwell October 2,
1832, and educated at the school of the Society of Friends,
Grove House, Tottenham, to which Society his family belonged.
He was one of the sons of the originator of the old firm of Tylor
and Sons, Brass-founders, Newgate Street, K.C., of which his brother
Alfred Tylor, F.G.S., was for many years chief. Abandoning
business E. B. Tylor devoted himself to the study of the races of
mankind, their history, languages, and civilization, and had the
advantage, at 24 years of age, to accompany his friend Henry Christy
on a journey in Mexico in 1856; the archeological objects then
collected now form part of the Christy Collection in the British
Museum. His researches are embodied in Anahuac, or Mexico and
the Mexicans (1861), Researches into the History of Mankind (1865),
and Primitive Culture: Researches into the Development of Mythology,
Philosophy, Religion, Art, and Custom (2 vols., 1871; 8rd ed., 1891).
He was elected a Fellow of the Royal Society in 1871, Honorary
LL.D. St. Andrew’s (1878), and D.C.L. Oxford (1873). In 1883 he
was appointed Keeper of the Oxford University Museum, Reader,
and in 1896 the first Professor, in Anthropology. In 1858 he married
Anna, daughter of the late Sylvanus Fox, of Wellington, Somerset.
to which place he retired after resigning his post at Oxford. He
received the honour of knighthood in 1912.
1 See also Nature, January 11, 1917, p. 373.
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J. ORIGINAL ARTICLES. Page REVIEWS (continwed). Page
A Rock Stream in East Iceland.
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F.G.S. (Plate Vianda Text-map.) 97
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1, VIEW OF LODMUNDARFJORD, EAST ICELAND.
2 GREAT FALLEN BLOCK OF LIPARITE, JAFNADAL.
THE
GEOLOGICAL MAGAZINE
NEWoseRleS ) DECADE Vile VOLS IM.
No. III.—MARCH, 1917. . fs.
Cogs (x MAR 26 191.
ORIGIN AL ARTICLES.
aae < y
I.—A Remarxaste Rock Srream in Hast Icenan Non ee
ea lisse:
By LEONARD HAwkgss, M.Sc., F.G.S. tenons acne
(PLATE VI AND TEXT-MAP.)
N his account of the volcanoes of Iceland, Thoroddsen describes
two types of acid lavas which have been extruded in post-
Glacial, prehistoric times. First are the lavas of the Torfajokull
district, of the usual nature of acid flows, building up a compact mass
of bluish-grey rock with an outer casing of obsidian and pumice.
These lavas have been poured out in the post-Tertiary country, but
the second type of stream is found most frequently in the older
parts of the island, which otherwise have witnessed no volcanic
eruptions since Tertiary times. This type of flow results from
eruptions of a peculiar character in which ‘‘ vast outflows of half-
melted and unmelted masses of liparite, poured out from cauldron-
shaped depressions, stretch down into the lowlands” (1, p. 503).
The best example of these ‘‘ Liparitische Blockstrome”’ occurs in the
Lodmundarfjord district, E. Iceland, and is especially described by
Thoroddsen (2, pp. 159-161). In this paper the contention is put
forward that the Lodmundarfjord blockstream is not a lava-flow but
an unusual type of glacial moraine.
Unfortunately the magnificent topographical map of Iceland in
preparation by the ‘‘ Generalstaben”’ of Copenhagen does not yet
include the Lodmundarfjord district, and no claim of special accuracy
is made for the rough sketch-map of Fig. 3, which is given to render
the description below more intelligible. The Lodmundarfjord,
running approximately east and west, is bounded on both sides by
ramparts of Tertiary plateau-basalts from two to three thousand feet
in height. The fjord is continued inland in a broad flat valley, the
Bardarstadadal, and a raised beach, 23 metres high, after Thoroddsen
(2, p. 103), shows that the sea formerly stretched far up the valley.
The only notable breach in. the southern wall occurs at 800 feet, the
mouth of a broad hanging valley which forms part of the pass
(the Hjalmadalshe1%i, czrca 2,000 feet) leading over to the Seydisfjord.
On the north side, near the end of the fjord proper, a broad valley,
the Hraundal, leads up from sea-level to the inland plateau in
a north-westerly direction.. The mountains of the Lodmundarfjord
are built up exclusively of basalts and red tuff partings, but a thick
series of acid rocks is exposed in the cliffs bordering the upper reaches
of the Hraundal, being the southern extension of the largest area of
DECADE VI.—VOL, IV.—NO. III. 7
98 Leonard Hawkes—Rock Stream in East Iceland.
acid rocks in Iceland. Especially noteworthy is the mountain
Skimhéottur, cerca 3,000 feet high, into which a huge cirque extends.
The cirque walls are very steep, falling to a broad gravelly plain
about 750 feet high, over which a river—the Hrauna—meanders
in a south-easterly direction till it cuts through a rise of about
50 feet, the beginning of the blockstream, and takes a rapid course
through a gorge to the fjord. The blockstream is a chaotic assemblage
of large angular blocks of liparite, a great number being twelve or
more feet in diameter, with an extremely uneven hummocky surface,
forming a wilderness known as the ‘‘ Hraun”’.
‘‘Hraun” is an old Norse word meaning ‘‘a rough place”,
‘Ca wilderness’, but in Iceland it came to signify ‘‘a lava field when
4 1
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Fic. 3.—Sketch-map of the Lodmundarfjord District. H=the Hjalmadal ;
B=the Bardarstadadal; Se=the farm Severendi; St=the farm Stakkahlid.
cold”, ‘‘a burnt place’’, being so used in the Sagas as well as in
modern times (3). Thoroddsen regards the blockstream as a lava-+
flow extruded from Skumhottur. ‘The rough block surfaces of some
acid lavas are well known and cited as a parallel, albeit the
exceptional unevenness of the ‘‘ Hraun”’ is taken as an indication that
the lava was exceptionally viscous, and the daring suggestion is made
that the liparite was first intruded into the Tertiary basalts and
cooled down so slowly that when the plateau was dissected by
dislocation and erosion the still hot magma flowed out as a stream of
half-melted blocks (2, p. 161). A closer examination of the district
reveals little to support this hypothesis. It is clear that the greater
Leonard Hawkes—Rock Stream in Hast Iceland. 99
part of the material composing the ‘‘ Hraun”’ comes from Skiimhottur,
but I am not satisfied that ‘‘the lparite is for the greater part
intrusive here” (2, p. 276). The acid series is estimated to have
a maximum thickness of 1,800 feet, and though the actual junction
was covered with snow (June month) the basalts did not show any
signs of disturbance commensurate with that to be expected if the
main part of the series were intrusive. The acid rocks here are
similar to those which the author has described from the neighbouring
Seydisfjord (4, pp. 391-2), consisting of tuffs, breccias, obsidian, and
liparite. One breccia underlying the main mass contains large
fragments of liparite, pitchstone, and obsidian, and the farmer at
Stakkahh’% has some petrified tree trunks which were obtained here..
Thus with proof of the extrusive nature of part of the series, and in
the absence of indications of intrusion with the exception of some
dykes, it seems probable that the main mass was extruded in
' Tertiary times, as is the case with so many occurrences of acid rocks
in Kast Iceland (5, p. 468).
The chief objection to the hypothesis of a lava origin is the nature
of the ‘‘Hraun”’ itself. Examination revealed the fact that the
rock stream is not, as has been stated, exclusively composed of
spherulitic liparite, but contains pitchstone, obsidian, pumice, and
basalt. A beautiful mahogany obsidian is especially noteworthy,
and all the rocks mentioned are to be seen in situ in the
Skumhottur mountains. In the gorge of the Hrauna the ‘‘ Hraun”’
is seen to be fragmental and composite to the base and to contain
much gravelly material. I saw no sign of a liparite dyke in the
gorge, or any evidences of fumarolie action in situ as reported by
Thoroddsen.
Perhaps the most interesting part of the rock stream, which is
about one and a quarter miles in length, is its termination in the
main fjord valley. Near the fjord the blocks become smaller until
the final fan of fine fragmental material is reached, resting on the
floor of the Bardarstadadal, north of the FjarSara. These deposits
are seen in Pl. VI, Fig. 1. South of the river, at and to the west
of Severendi, are a number of conical mounds commonly composed
of liparite fragments, with obsidian and basalt less frequently. One
of the largest mounds was elliptical in plan, 100 feet by 80 feet,
with a maximum height of 23 feet, and contained a block of liparite
7 feet in diameter. Proceeding westwards the mounds become
fewer and further between until about half a mile from Severendi
the last one occurs close to the southern wall of the valley. Many
of the mounds are exclusively formed of one type of rock, some of
obsidian and others of liparite, and they furnish the clue to the
problem of the origin of the ‘‘ Hraun’’. Owing to its jointing
1 In connexion with the lava hypothesis as advanced by Thoroddsen it is of
interest to note that the block surface of some lavas in the Cordilleras of
South America was taken by Humboldt and de Boussingault as evidence
of eruption in fragmentary form, but Scrope considered this an ‘‘ improbable
hypothesis’’, pointing out that the fragmentary nature of lava streams is
a property restricted to their upper and under surfaces, the main mass being
compact (6, p. 70).
100 Leonard Hawkes—Rock Stream in Hast Iceland.
liparite commonly weathers out in very large blocks. A striking
demonstration of this is to be found at the head of the Jafnadal,
StoSvarfjord, 8.E. Iceland. The valley ends in a large cirque, the
walls of which are chiefly composed of liparite. The plain about
a thousand feet below the top of the cirque wall is dotted over with
blocks of liparite which have rolled from above over the steep snow
slopes. The largest of these blocks, measuring 90 feet by 46 feet by
40 feet, has split in two at its final resting-place (see Pl. VI, Fig. 2).
The complete weathering down of such a block would give rise to
a mound like the largest of those in the Lodmundarfjord valley.
The mounds clearly result from the weathering of large blocks in
situ, and the only agency which can be imagined to have brought
them to their positions so far west is that of ice floating in the sea,
which once stretched far up the valley as evidenced by the raised
beach deposits. Thus the ‘‘Hraun’”’ is. of raised beach age and
was not formed subsequently (2, p. 159), and it dates from the
end of the last Ice Age, when the glacier of the fjord valley had
retreated. he raised beaches along the fjords of the Folden district,
Salten, N. Norway, are considered by Rekstad to be formed of
morainic debris, and to date from the time when glaciers flowed
down side valleys to the shores of the fjords (7, pp. 10-11).
A similar explanation suffices for the deposits described in the
Bardarstadadal, and thus the “‘ Hraun”’ is to be regarded as the
moraine of a glacier flowing down Hraundal.
The morainic theory is rejected by Thoroddsen on two main
grounds. These are (1) that ‘‘ the whole mass of debris and blocks
consist exclusively of one particular rock, spherulitic liparite, whilst
a moraine must contain both’’, and (2) ‘‘no ice scratches are found
on the blocks”’ (2, p. 160). As mentioned above, besides obsidian
basalt does enter into the composition of the ‘‘ Hraun”’, though to
a remarkably small extent. This is partly understood when we
consider the brittleness and fissility of liparite as contrasted with the
toughness of basalt, whereby the former succumbs more easily to
erosive agencies than the latter. The readiness with which lparite
breaks up would itself account for the absence of ice-scratches on the
blocks. During a field examination, extending over several weeks,
of the acid rocks of East Iceland, the writer never saw an ice-scored
surface of liparite.
I regard the ‘‘ Hraun”’ as a surface ‘“‘ block-moraine”’, andit would
not bear ice-scratches. The material probably did not fall slowly on to
the glacier as a talus stream, but descended in great landslides, as has
been suggested for some of the rock streams in the San Juan Mountains,
Colorado, which are characterized by ‘‘the remarkable quantity of
relatively coarse material comprising them, and the fact that the
ereater part of this must have been carried on the surface of the ice”’
(8, p.25). The ‘‘ Hraun”’ presents many analogies to the rock streams
of the San Juan Mountains. These latter are comparable in size,
the hummocky surface is similar, they are often composed of Tertiary
acid volcanic rocks, and the topography of the district is that of
a “dissected and glaciated plateau of more or less horizontally bedded
volcanic rocks” (9, p. 11).
Leonard Hawkes—Rock Stream in Hast Iceland. 101
An interesting case of a landslide on to a glacier, which illustrates
what has probably taken place in the formation of the ‘‘ Hraun”’, is
recorded by Freshfield from the Caucasus. ‘‘ The Shikildi Glacier
presented itself as an advancing mound of huge blocks of grey
eranite. .. . In 1866 a noise as of thunder was heard by the
shepherds of the Baksan, and a great cloud of smoke or dust was
observed to issue from the recesses of the chain under Ushba. . .
After a time it was ascertained that a great rock had crashed down
from the cliffs on the east side of the Shikildi Glacier. . . . We saw
next day the gap in the mountain side which had provided the
enormous masses now strewn over the lower glacier. . . . I neversaw
such a goods-train of aglacier. . . . The immense size of the single
blocks and the complete burial of the ice under them are the features
which give their extraordinary character to the moraines of the
Shikildi’’ (10, pp. 137-8). It is interesting to note that in the Saga _
relating the colonization of the Lodmundarfjord, crea 900 a..,
mention is made of a landslide, and whilst this cannot refer to the
main mass of the “ Hraun”’, there is little doubt that we here have
evidence that sliding has taken place in historic times.’
Many of the San Juan rock streams are regarded as landslides which
had no connexion with glaciers. It would be possible to regard
the ‘* Hraun’’ as such, and the mounds in the Bardarstadadal as being
formed from blocks transported by the shore ice-foot when this broke
up. But apart from the fact that the general aspect of the ‘‘ Hraun”’
is rather that of a moraine than a landslide, it is very probable that
under the severer climatic conditions giving rise to an ice-foot,
a glacier would exist inthe Hraundal. Strictly the term ‘‘ moraine”’
should be used only of material which has been actually transported
by a glacier, rock debris which falls on to a stationary or retreating
glacier being termed ordinary talus accumulations or landslide
material according to degree. There will be cases which stand near
the border-line between these two classes which will only be correctly
placed after very careful investigation. Whilst reserving a final
decision until the writer can make a more thorough examination, he
is inclined to the opinion that the ‘‘ Hraun”’ has been transported to
some extent by a glacier and is therefore a true glacial moraine.
The rejection of the ‘‘lava-flow’’ hypothesis removes an exception
to an important generalization, i.e. the post-Glacial instances of
voleanic activity in Iceland are confined to the Quaternary Formation
districts, so that the post-Glacial vulcanism is to be regarded as the
direct continuation of the Quaternary and not the Tertiary activity
(12, p. 18). It may be considered remarkable that the same
1 ‘* Todmund the Old was the name of a man, and another was Beowolf his
sworn brother. They came to Iceland from Thule-ness in Vors. Lodmund
east his porch-pillars overboard while he was at sea, and said that he would
settle where they were drifted ashore. And the sworn-brethren made Kast-frith,
and Lodmund took in settlement Lodmund-frith, and dwelt there three
winters. Then he heard of his porch-pillars being inthe south of the country.
And with that he put on board his ship all that he had. . . . And when he
had been a little while, there was a great rumbling noise, and they saw a great
earth-slip fall upon the homestead which Lodmund had set up and dwelt in.”’
Landndamaboc, iv, 9 (11
102 Dr. D. Ellis—A Jurassic Fossil Fungus. :
rock-stream should be regarded by one observer as a lava-flow and
by another a glacial moraine, but a similar case is on record in the
history of Icelandic geology. Anaccumulation of liparite blocks and
debris in the Vatnsdal, Hunafjord, North Iceland, was thought by
Schmidt to result from a post-glacial volcanic eruption (18, pp. 764-5),
but it is now considered to date from the end of the Ice Age and to
represent a great fall of rock on to a glacier (2, p. 271).
REFERENCES.
1. TH. EHORODDSEN, ‘* Explorations in Iceland, 1881-98’: Geogr. Journ.,
Lond., vol. xiii, 1899.
2. TH. THORODDSEN, ‘‘ Island. Grundriss der Geographie und Geologie ”’ :
Erganzungsheft No. 152 und 153 zu Petermanns Mitteilungen, 1905.
CLEASBY & VIGFUSSON, Icelandic and English Dictionary, Oxford, 1874.
LL. Hawkes, ‘‘ The Building up of the North Atlantic Tertiary Volcanic
Plateau ’?: Gmhou. MAG., Dec. VI, Vol. III, pp. 385-95, 1916.
5. Ib. Hawkes, ‘‘ The Acid Rocks of Iceland’’: Abstract, GEou. MaG., 1916,
pp. 468, 469.
. G. P. ScropE, Volcanos, London, 1862.
J. REKSTAD, ‘‘ Om Strandlinjer og Strandlinjedannelse ’’: Norsk. Geol.
Tids., Bd. iii, No. 8, Kristiania, 1915.
8. W. Cross & BE. Howe, Silverton Folio, No. 120. U.S. Geol. Sury., 1905.
9. Kh. Howe, ‘‘ Landslides in the San Juan Mountains, Colorado’’: Prof.
Paper No. 67. U.S. Geol. Sury., 1909.
bel
“1D
10. D. W. FresHFiELD, The Exploration of the Caucasus, vol. ii, London, -
1896.
1l. Vierusson & POWELL, Origines Islandice, Oxford, 1905.
12. H. Pserurss, ‘‘Island’’: 2. Hand. d. Reg. Geol., Heidelberg, 1910.
13. C. W. Scumip7, ‘‘ Die Liparite Islands in geologischer und petrographischer
Beziehung’’: Zeits. d. Deut. geol. Ges., xxxviii, p. 737, Berlin, 1885.
EXPLANATION OF PLATE VI.
Fria. 1.—General view of the Lodmundarfjord ‘‘ Hraun’’, looking north from
Severendi. The Skimhéttur cirque is seen in the middle background.
The main fjord valley and the ‘‘ Hraun’’ deposits north of the River
FjarSar4 occupy the foreground. ,
Fig, 2.—A great fallen block of liparite, now split into two, in the Jafnadal,
StéSvarfjord, East Iceland. A hammer may be distinguished on the
face of the nearer block, not far from its base.
11.—On run Jurassic Fosstzr Funeus, Puvcouycires l’ropINGHAMII
) (inxs),
By Davin Evuis, Ph.D:, D.Sc. ‘
(WITH PLATE VII AND A’ TEXT-FIGURE.)
[* a recent paper! the writer described structures which he had
_ found in the Frodingham Ironstone of Lincolnshire. The claim
that these structures are fossil fungi is one of more than usual interest,
for fossil fungi have not hitherto been recorded from the Jurassic rocks,
and, further, the decomposition established by this fungus must have
been carried out under marine conditions. Since the publication of
this paper criticisms as to the conclusions contained in it have not
been wanting, and it is proposed in the present paper to deal with
these criticisms and further to furnish a few additional data to.
supplement those that have already been given.
* “Fossil Micro-organisms from the J urassic and Cretaceous Rocks of Great
Britain ’’?: Proce. Roy. Soc. Edinburgh, vol. xxxv, pt. i, No. 10, 1915.
ee
Grou. Maa., 1917.
Pirate VII.
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A JURASSIC FOSSIL FUNGUS.
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Dr. D, Hlus—A Jurassic Fossil Fungus. 1038
Before dealing with the criticisms it must be borne in mind that
the conclusions arrived at in the former paper were based on biological
grounds. The structures were such as a biologist recognizes to be
characteristic of fungi. They take the form of tubes coated with
ferric oxide and conform to fungal structures in the following
respects :-—
Sketch of animal remains in Dunliath Ferruginous Limestone (Jurassic),
N.W. Scotland, found in association with fungal hyphe. x 1400.
- 1. The tubes are cylindrical and possess a membrane comparable
to the membranes of modern fungi.
2. The diameter of the tubes is 2 to 4 (s45— sto mm.).
8. They branch and interweave in the manner characteristic. of
modern fungi. (In addition they also form whorled branches:
104. Dr. D. Ellis—A Jurassic Fossil Fungus.
whilst not characteristic of modern fungi this feature is characteristic
of other plants.)
4. They are uniform in size.
5. They form terminal dilatations which are comparable to the
sporangia of modern fungi. This is particularly so with regard to
their size as compared with the tubes which bear them, to their
shape, and to their terminal position. In all respects they suggest
the development of terminal reproductive organs on hyphe (Pl. VII,
Hp),
6. In two instances, one of which is shown in Pl. VII, Fig. 2,
rounded structures have been noted inside the terminal dilatations
which in every essential particular suggest the spores which are
formed inside the sporangia of modern fungi.
7. The structures in question are found in an organically formed
rock (Pl. VII, Fig. 3).
The circumstantial evidence upon which alone the whole case
naturally rests seems thus, from a biological standpoint, to be
complete enough to allow of little doubt as to the matter. The
points with which we shall now be dealing have had their inspiration
in the minds of those accustomed to regard such matters more from
the geological and mineralogical than from the biological standpoint.
1. The structures in question may be of mineral and not of organic
origin. —Throughout the history of this subject mineral secretions
have been repeatedly mistaken for organic remains. So far as the
imitation of plant organs is concerned the structures imitated are
leaves and cellular tissues. But from the nature of the case the
plant patterns executed by these secretions are of a simple form and
their variety of a very limited order. Whilst such secretions may
imitate a cellular or a tubular structure, it is difficult to see how the
whole atmosphere in which a phycomycetous fungus lives can be
simulated so very faithfully by a mineral secretion that not only are
hyphee and hyphal membranes reproduced but also sporangia (Pl. VII,
Fig. 1) and even spores (Pl. VII, Fig. 2). Further, the relative
dimensional proportions of the parts are so faithfully adhered to that
even when examined with the highest powers of the microscope,
a trained eye cannot detect any details of structure inconsistent with
the structural plan of phycomycetous fungi. Such wonderful fidelity
in detail would demand strong evidence of an opposing nature to
dismiss the claim that the structures in question are fossilized fungal
remains.’ The slides have been submitted to several competent
mineralogists for their opinion of the structures from the minera-
logical standpoint. In no single case was evidence forthcoming to
suggest that a mineral interpretation of these tubes and expansions
would fit the facts of the case. Among those to whom the slides were
submitted was Dr. Flett, of the Geological Survey, Edinburgh, whose
opinion on this point will command respect. Dr. Flett stated that he
was prepared to accept the organic origin of the structures indicated
to him and that he knew of nothing in the mineralogical world that
approximated to them. From the mineralogical standpoint no single
positive fact has been brought to light which invalidates the claim
for organic origin made from a study of the biological data.
Dr. D. Hllis—A Jurassic Fossil Fungus. 105:
2. The structures may have been caused by insect borings.—If the
causation of these threads and vesicles is not to be ascribed to a
mineral infiltration, and an organic origin is granted, there still
remains another possible origin, viz. that the tubes were due to
insect borings. This possibility has been suggested to account for
the tubes and vesicles. This criticism would have weight were it
not for the extreme smallness of the tubes. These measure only
=t+smm. In previous cases where this criticism had weight, as for
example in the case of the Rhizomorpha Sigillariee of Lesquereux,
the tubes under consideration were 2—3 mm. in diameter, and the
claim was made that they were rhizomorphal cords of fungal hyphe.
Being commensurate in size with known insect borings, the criticism
that they might have been produced by insects was quite legitimate.
We are here, however, dealing not with cords of hyphe, but rather
with the individual strands such as are commonly found in the woody
tissues of many plants. he possibility of their preservation need not
be discussed, as their appearance in the tissues of fossil wood is too
common and too well known to admit of any doubt on the matter.
It is not conceivable that any insect either during Mesozoic times or
at any time could make borings which simulated the biological
characteristics of a fungus on such a minute scale. It is the more
incredible when we reflect that these supposititious borings would be
excavated in the body of some animal fragment, the natural habitat
of many phycomycetous fungi, and not in the harder tissues of
trees in which insect borings are usually found.
3. Criticisms arising from the fact that whilst the parasite (or sapro-
phyte) has been preserved the details of structure of the host in which vt
lived have not been preserved.cIn answer it may be stated that
the discovery of this organism was not entirely due to an accidental
circumstance, but was rather the successful issue of a specific
search. In the author’s researches on modern iron-bacteria, the
membranes of which are impregnated with the highly resistant
ferric oxide, he was led to the conclusion that if iron-bacteria or
their representatives existed in former ages the chances of their
preservation in fossil form were very strong. When the opportunity
occurred ironstones and ferruginous limestones of various ages were
carefully searched for iron-absorbing micro-organisms. ‘The tough-
ness and hardness of such membranes can be observed by anyone who
cares to examine the dead membranes of the modern ochre-bacillus
(Leptothria ochracea). The search did not reveal fossil iron-bacteria
as was expected, but it did bring to light a fungus possessing the
same characteristic of absorbing iron-compounds from the surrounding
water. An organism thus protected would obviously stand a much
better chance of preservation than the soft tissues of the animal
fragments inside which a fungus of this character must necessarily
abide. The slides containing these structures consist of fragments
of organic matter embedded in a calcite matrix (Pl. VII, Fig. 3).
The threads and vesicles were invariably found inside the organic
fragments and not in the matrix. An example is shown at a in
Pl. VIi, Fig.3. Thisfragment is seen photographed on a higher scale
of magnification in PI. VII, Fig. 4. In the latter case the threads
106 °—s éD) rr. VD. Ellus—A Jurassic Fossil Fungus.
under discussion are plainly revealed. It cannot be reasonably doubted
that the fragment marked ain Pl. VII, Fig. 3, is an organic fragment
similar to the other obviously organic fragments that are to be seen
in the same field. It is unfortunate that in the Frodingham Iron-
stone in which these were found no traces of the internal structure
of the animal host could be discerned, whilst the details of the
structure of the parasite contained in it were so clear. This point,
however, is capable of an easy explanation if it be assumed that the
threads and vesicles represent a fossil fungus which during tts
lifetime had the same power of absorbing iron salts that the iron-
bacteria possess at the present day. Under these circumstances the
membranes of the fungus would be impregnated with ferrie oxide
during its lifetime, a circumstance which would render these
membranes much more resistant to disrupting forces than the
soft tissues in which they were embedded. Further, it is
possible to conclude with a fair approach to certainty that
the iron on the threads was laid down for the greater part
during their lifetime. The reason for this conclusion is as follows:
A study of the iron-bacteria has brought to light the fact that the
deposit of iron on their membranes varies in consistency according to
the age of the thread. Young threads have a sharply contoured
membrane of a brownish-yellow colour. In older threads the nature
of the deposition and of the membrane is quite different. The colour
of the iron changes to a deeper brown, the quantity of it is greater,
and the membrane, instead of being a continuous sharply outlined
structure, is a discontinuous irregular line and wanting in sharp
lines of demarcation. All gradations can be observed by a close
study of the membranes of Leptothrix ochracea, the best known of the
iron-bacteria. It is surely a significant fact that the same gradations
ean be observed on the membranes of the threads which we are
now discussing. ‘The appearance of these gradations is easily
explicable if we assume that the tubes are the remains of an iron-
absorbing fungus, but on the assumption that all the iron in these
rocks, including the iron on these tubes, resulted from a subsequent
infiltration of iron-ckarged water, the explanation is not so easy. It
cannot be doubted that the bulk of the iron in these rocks arrived
there by subsequent infiltration, but it is at least highly probable
that some of it has never been absent from the material from which
these rocks were formed. If the iron on these tubes had got there
solely by infiltration, it would naturally be expected that all the tubes
would have a deposit of a uniform nature; the tubes, on the other
hand, show those changes which come about when iron enters the
living cell, and after undergoing changes due to metabolism is thrust
out again and deposited on the outer part of the membrane.
We muy assume that the presence of the iron covering isa sufficient
explanation of the preservation of these threads and vesicles. Whilst
a search among the organic particles of the Frodingham Ironstone
containing the fungus failed to reveal traces of the structure of the
host, a measure of success was achieved by searching the similar
Jurassic ferruginous limestone at Dunliath in the north-west of
Scotland. In Pl. VII, Fig. 6, for example, we see an organic
Dr. D. Ellis—A Saerasene Fossil Fungus. 107
fragment showing traces of animal cells (@), and also a few hyphe
of some unknown fungus (6). Again, in others inside similar organic
fragments structures like those represented in the T’ext-figure and
in Pl. VII, Fig. 5 were met with. These are obviously the remains
of some animal cells, although in this condition it is impossible to
specify any further with regard to their nature. The point of the
matter lies in this, that these organic fragments from Dunliath
contain the remains of both animal cells and fungal threads, both
very incomplete and very indefinite: in the Frodingham Ironstone
the disruption of the animal cells has been complete, whilst the
fungus, thanks to its protective covering, has been particularly well
‘preserved.
4. Doubts arising from the fact that the threads and vesicles were
Sound in material known to have suffered decomposition in sea-water.—
. Whilst it is true that no fossil fungi have so far been found of
which it could be definitely stated that they had effected decom-
position in salt water, the reason for this does not le in the fact
that there is anything inherently impossible in the idea, for that
would imply that decomposition of organic matter cannot take plave
in salt water, which is contrary to experience. It is true that the
vast bulk of marine decomposition is due to the activity of bacteria,
but even in this field a large proportion of the organisms which carry
on this decompesition belong to the sulphur bacteria, several species
of which group are composed of long threads, thus approximating in
their habits to the threads of which the aquatic fungi are composed. —
In the artificial cultivation of many of the thread-forming sulphur
bacteria success attends the attempt only if sea water instead of
fresh water be employed. A still more powerful argument is the
fact that in the cultivation of some of the Saprolegnias, a group of
phycomycetous fungi, the use of sea water is recommended in making
up the nutrient medium. So that even in the case of modern plants
. of the same group we meet with fungal decomposition under marine
conditions. Anyone who has studied the shores of Denmark can
satisfy himself of the extent to which marine decomposition can
operate in the scavenger work of Nature. The shallow Jurassic seas
must have had huge shallow lagoons in which of necessity scavenger
work on a large scale must have been in operation. It would be an
extremely rash statement to assert even apart from our experience
of modern fungi that no thread fungi could have contributed to this
‘ work. - For even if such fungi did not exist at the present day, there
are so many closely allied forms that effect decomposition in salt
water that marine fungi in a fossil form would not have been
a matter for surprise.
Conclusion.—Vhe study of the tubes and vesicles classed under
Phycomycites Krodinghami had revealed their organic nature by the
closeness with which their structures followed those of modern fungi.
The resemblances extended even to minute points of structure, and
were so great that from a biological standpoint no doubts were enter-
tained as to the fact that we were dealing with fossil fungi allied to
the modern Phycomycetes. It remained to inquire whether any
positive evidence could be adduced, or any facts brought forward on
108 Professor Yakovlec—On Rugose Corals.
mineralogical or geological grounds, which could impair the position
taken up. The criticisms on theoretical grounds which have been
brought forward have not invalidated the claim for these structures
which the writer has brought forward. It is proposed to present
the slides to the British Museum, so that they can be made available
for inspection and reference.
EXPLANATION OF PLATE VII.
Fic. 1.—Frodingham Ironstone from Jurassic rocks of Lincolnshire. From
interior of fossilized organic fragment. Shows hyphe, one bearing
a fully developed terminal sporangium. a=sporangium, 6=hypha,
c=calcite matrix. x 530.
2.—Frodingham Ironstone from Jurassic rocks of Lincolnshire. Shows
two sporangia of Phycomycites Hrodinghamw. In the left sporangium
(c), partially extruded from it, is seen a spore (b). q@ is a portion of
a small oolite. » 166.
., 3.—Organic remains in Frodingham Ironstone. Atqais shown a fragment
in which fungal hyphe were found. x 18.
4.—The organic fragment marked a in Fig. 3 shown on a larger scale.
The fungal hyphe are distinctly visible. x 116.
., 5.—From Dunliath Ferruginous Limestone (Jurassic, N.W. Scotland).
Remains of animal cells. x 466.
., 6.—A semi-diagrammatic sketch of a portion of an organic fragment in
the Dunliath Ferruginous Limestone. Inside the fragment are seen
the remains of animal cells and of fungal hyphe. The branched
tubules are the hyphe and the dark rounded fragment the animal
cells.
IJ1.—Own rue Orcanization or THE Rugosr Corats anD THE ORIGIN
OF THEIR CHARACTERISTIC PECULIARITIES.
By Professor N. N. YAKOVLEV, Petrograd, Russia.
(PLATE VIII AND FOUR TEXT-FIGURES.)
URING the last ten years I have published a series of memoirs '
on different questions concerning the morphology and biology
of the Rugose Corals. In these memoirs I have elucidated the
ground-form of the polyparium of the solitary Rugosa, the mode of
its attachment to the substratum, the origin of the characteristic
arrangement of the septa, and the origin of the fossule in dependence
on this form and attachment. I have established the connexion
between the form of the polyparium of the Rugosa (including that
of the fossule) and the life of these corals in definite environmental
conditions.
1N. Yakovlev, ‘‘Die Fauna der oberen Abtheilung der palaeozoischen
Ablagerungen im Donetz-Bassin. II. Die Korallen’’: Mém. Com. géol.
St. Petersbourg, N.S., livraison xii, 1903.- ‘* A contribution to oe Characteristic
of Corals of the group Rugosa’’: Ann. Mag. Nat. Hist., VII, vol. xili,
pp. 114-17, 1904. ‘ Ueber die Morphologie und Morghacenie ‘abe Rugosa ”’ :
Ver. Russ-k. Min. Ges. St. Petersbourg, vol. xli,, pp. 394-415, 1904. ‘* Die
Entstehung der charakteristischen Higentiimlichkeiten der Korallen Rugosa”’ :
Mém. Com. géol., St. Petersbourg, N.S., livraison Ixvi, 1910. ‘‘ Les récifs
coralliens existent-ils dans le paléozoique?’’: Bull. Com. géol. St. Petersbourg,
vol. xxx, No. 10, pp. 847-57, 1911. ‘‘ Studien tiber die Korallen Rugosa ”’ :
Mém. Com. géol. St. Petersbourg, N.S., livraison xevi, 1914.
Professor Yakovlev—On Rugose Corals. 109
Referring to the colonial Rugosa, I have explained how the
characteristic forms of the colonies are correlated with the mode of
multiplication, and demonstrated the part played by these corals in
reef-building. Here and there I have pointed oyt differences between
the Rugosa and the Hexacoralla, which do not admit the former to
be considered as the progenitors of the latter, though this is probably
claimed by the majority of paleontologists and zoologists.
This examination (pursued by me for many years) of the form and
functions of the Rugose Corals and of the questions they raise, I now
look upon as sufficiently complete to render desirable a review of the
results of my work, which throws fresh ight on the Rugosa as well
as providing a causal explanation of the origin of the peculiarities of
this specialized group. In conformity with the character of the
present paper, the exposition will be given concisely, without
citations and references, without criticism of other authors, without
any details; those who are interested will find all this in my
previous publications.
The shape of the Rugose polyparium is considered to be, typically
conical. Herein the Rugosa differ from the Hexacoralla, which
mostly have a cylindrical polyparium; and this difference of body-
form may be seen in the soft-bodied Actinize now living. The
Rugosa are first found in Silurian rocks, but doubtless existed
previous to this, and before Silurian times the Rugose polyparium
had already departed from the fundamental simply-conical shape.
It had acquired, near its proximal end, a lateral attachment to the
substratum, unlike the basal attachment of the Hexacoralla (see
Pl. VIII, Figs. 1-4). This lateral attachment was correlated with their
life in epicontinental seas. The basal attachment of the cylindrical
(or, in rare cases, conical) polyparium of the Hexacoralla living in
deeper, calm water, as much satisfies the requirements of solidity as
the lateral attachment of the Rugose conical polyparium living in
a zone of the sea characterized by comparatively rough or at least
agitated water.
The lateral attachment, then, of the Rugose polyparium is an adapta-
tion to definite environmental conditions. It has modified the original
form of the simply-conical polyparium and has imposed upon it a definite
orientation correlated with the direction of the prevailing currents. For
a conical polyparium lying on one side on the sea-bottom must of
necessity turn away its mouth from the mud of the sea-bottom in
order to avoid suffocation. Thus thesimple cone with a straight axis
becomes one with its axis curved in one plane—a form resembling
the horn of an ox, and suggesting such trivial names as cornu,
_ corniculum, cornucopia, cornu-bovis, ceratites, buceros, etc. Moreover,
all the individuals of one locality were orientated in the same
direction, namely, with their convex sides towards the direction of
the prevailing current (see Text-fig. 1). Only thus will a polyparium
of such a shape offer the maximum resistance to wave- and current-
action tending to tear it from the substratum.
Now the scar formed by the attachment of the polyparium to the
substratum as well as the root-like processes serving the same
purpose necessarily occur as a rule on the convex side of the corallum.
110 Professor Yakovlev—On Rugose Corals.
And in this respect, as well as in its general form, the coral already
shows an external bilateral symmetry. Scars of attachment and
root-like processes, both on the convex side, and a general external
bilateral symmetry, characterize all the known Rugosa from the
Silurian rocks, the earliest in which they have yet been found, to
the Permian in which the last Rugosa occur. Further, when, owing
to the character of the sea-bottom, there is no possibility of attach-
ment and the coral consequently is free, the polyparium, whether
_ of a Rugose or Hexa-coral, takes on a flat, discoid shape (Palgocyclus,
\ Microcyclus, ete.) But, in spite of its not leaning over, the Rugoase
Coral retains its bilateral symmetry, shown externally chiefly by the
apex which lies excentrically, while that of the Hexacoral is central.
That is to say, in spite of the removal of the conditions producing
bilateral symmetry, the discoid Rugose Coral exhibits it. Is not this
an example of the inheritance of acquired characters ?
Another form showing the tendency to retain bilateral symmetry
after the conditions which caused it have been removed is that
‘y taken by unattached genera such as Calceola, Platyphylium, and other
operculate corals. These are curved, flat on the lower side, and
YEXT-FIG. 1.—Diagram representing two polyparia of solitary Rugosa growing
side by side. ‘The arrows outside the polyparia indicate the direction of
the prevailing current, and those within the calices that of the water along
the channels formed by the fossule. H, G, S, the positions of the
Main, Counter, and Alar fossule respectively. Nat. size.
provided with an operculum whose function is to prevent the
penetration of mud into the coral’s calice. Operculate corals are
probably polyphyletic in origin, and, as would be exe occur
only among the Rugosa.
The last external character dealt with is the fr equently occurring
phenomenon of ‘‘Rejuvenescence”’. The term is inappropriate, since
young individuals also are subject to it. Rejuvenescence consists of
a periodically repeated retraction of the calice as if by shrinking or
by the appearance of a daughter coral produced by intracalicinal
budding. Rejuvenescence, especially in the broadly conical forms,
is easily explicable, in fact only to be expected, when it is con-
sidered how inconvenient and disadvantageous from a mechanical
point of view a considerable upward expansion of the polyparium
would be to the Rugosa with their typically conical. polyparium.
Turning from the external to the internal characters of the Rugose
skeleton, we shall find that they are determined by the curved
condition of the conical polyparium. We shall consider, first of all,
the characteristic arrangement of the secondary septa and their
Professor Yakovlev—On Rugose Corals. 111
relation to the primary septa—a condition peculiar to the Rugosa.
The works of Duerden, Carruthers, and others have shown that the
secondary septa develop in four adjoining (and in four only out of
s1x) primary interseptal chambers, and are bilaterally symmetrical
in their arrangement. ‘Two of the primary septa lie in the plane of
bilateral symmetry of the coral. About one of these—the Main-
septum—the secondary septa (as seen at their outcrops on the wall
TEXT-FIG. Z.—Diagram showing the arrangement of the outcrops of the septa
on the surface of the polyparium, according to whether the mouth is at
right angles to the concave side (above), to the convex side (below, on the
left), or to neither (below, on the right). The mouth is always at right
angles or nearly at right angles to the Counter-septum. S, Alar-septum.
aa, a'a’, the edges of the polyparium at different periods of its growth.
(After Yakovlev, 1904.)
of the polyparium) are arranged pinnately; while on each side of
the other—the Counter-septum—the secondary septa lie parallel
both to it and to each other (see Text-fig. 2). Two other primary
septa—the Alar-septa—lie somewhat at right angles to the Main-
and Counter-septa, thus dividing the calice into four quadrants, two
Main- and two Counter-quadrants. As seen at their outcrop on the
112° Professor Yakovlev—On Rugose Corals.
wall of the polyparium, the secondary septa are pinnately arranged
with regard to the Alar-septa in the Counter-quadrants and ne
parallel ‘to the Alar-septa in the Main-quadrants (see Text-fig. 2
above
Swok an arrangement of the secondary septa appears to be the
natural outcome of the mechanical conditions imposed by the curved
state of the conical polyparium. For the mouth of the conical
polyparium is generally in a plane perpendicular to its concave side
(Text-fig. 2 above); and the secondary septa have a tendency to
grow (as in all Anthozoa) in a plane perpendicular to that of the
mouth of the calice. Since the primary septa are already existent
in a curved polyparium, the secondary septa can grow in a manner
just stated, and unimpeded, in two only of the four Primary
quadrants, namely in the two Counter-quadrants. In the two other
quadrants, namely the Main-quadrants, the secondary septa cannot
grow in a plane perpendicular to that of the mouth, because, at least
in part, they would be impeded by the convex surface of the Alar-
septa (see the dotted line ¢-¢ in Text-fig. 2 above). Therefore they
grow, as may be observed, so that their outcrops on the coral-wall
are parallel with those of the Alar-septa.
But the Main-septum, sometimes, though comparatively rarely, lies
on the concave side of the coral. When this is so, the plane of the
mouth of the calice is perpendicular to the convex side of the coral
(see Text-fig. 2, below and on the left). Applying to this case the
principle that the secondary septa tend to lie at right angles to the
es of the mouth, we see that they can only thus grow unimpeded
in the quadrants lying on the convex side of the coral (now the
Counter-quadrants), whilst in the other pair of quadrants the growth
of secondary septa perpendicular to the plane of the mouth would
be impeded by the concave face of the Alar-septa.
A third, intermediary type also occurs (‘'ext-fig. 2, below and
right-hand side) in which the plane of the mouth is inclined approxi-
mately equally to the convex and concave side of the polyparium.
In this case the Main-septum occurs on the convex side of the coral
as it did in the first instance.
The fossule arise as a necessary consequence of ‘the primate
arrangement of the secondary septa. For there is always a com-
paratively broad space left between the youngest secondary septa and
the Main-septum in the two Main-quadrants, and between the
youngest secondary septa and the Alar-septa in the Counter-
quadrants (R, R, of Text-fig. 2 on the left) into which the soft
tissues settle doen and contribute to the widening of these spaces,
converting them into permanent cavities. These spaces are the
Main- and the Alar-fossule. The Main-fossula placed on the
convex or concave side of the corallum, according to the position of
the Main-septum, is really two juxtaposed fossule, but appears as
one, because of the shortness of the Main-septum. Consequently it
is wider than the Alar-fossule and is more constantly conspicuous
than these. ‘The shortness of the Main-septum is caused by the
soft tissues settling down into the Main-fossula. This sagging of
the soft tissue, pressing also against the sides of the fossula, caused
Professor Yakovlev—On Rugose Corals. 113
the deviation of the free edge of the secondary septa towards the one
preceding it, so as, finally, to fuse with it (@ with S, and Z, and
6 with a, in Text-fi fig. 3), giving the appearance (it is, of. course, only
an appearance) of repeated branching of the primary septa. The
septal fusion occurs in young individuals as well as in mature ones.
The older parts of many polyparia become cylindrical and straight
instead of conical and curved. In these there are no wide spaces
between the primary and secondary septa, and consequently there is
less development of the fossulz, and the fusion of the septa disappears—
in a word, radial symmetry, doubtless existent in the progenitors of
the Rugosa, is re-established.
Since the fourth fossula, that lying on each side of the Counter-
septum, is rarely visible in the Rugose skeleton, its origin must be
different from that of the other fossule. Its presence is due to the
fact that there are no secondary septa adjacent to the Counter-
septum. A study of the functions of the other fossule (of course
TEXT-FIG. 3.— Diagram of the calice of Hadrophyllum pauciradiatum,
Edwards & Haime. H, G, S, Main, Counter, and Alar septa respectively.
a-e, secondary septa. , F, F, Fossule. (After Duerden, 1905.) Nat.
size.
a purely hypothetical consideration, dealing, as it does, with the soft
parts of an extinct group of animals) may help to explain the origin
of the Counter-fossula. It appears to me that the function of the
Main- and Alar-fossule was to bring water to the axial part of the
coral, This is partly corroborated by the fact that all three lie in
one general direction, since the Alar-septa make an acute angle with
the Main-septum. I have established the hypothesis that the
solitary, curved polyparia of the Rugosa, during their life, were
orientated on the sea-bottom with their convex sides towards the
prevailing currents, a position most advantageous from a mechanical
point of view (see Text-fig. 1). This orientation itself would cause
the water to flow along the Main- and Alar-fossule towards the axial
parts of the coral; and the water would naturally find its exit on
the opposite side, namely along the Counter-fossula, which doubtless
arose for this purpose. For, though not constantly expressed in the
DECADE VI.—VOL. IV.—NO. III. 8
114 Professor Yakovlev—On Rugose Corals.
skeleton, the Counter-fossula would then be too important not to be
constantly expressed in the soft parts of the coral. If this were so,
the presence of the Counter-fossula in the soft tissues might actually
impede the formation of secondary septa in the loculi adjacent to the
Counter-septum (Text-fig. 4).
A last peculiarity of the solitary Rugosa correlated with the
curved, conical polyparium, is the fact that the number of secondary
septa present in the quadrants on the convex side, is sometimes
greater than the number of secondary septa on the concave side
(Text-fig. 4). Consequently, the position of the axis of the coral, as
defined by the point of meeting of the primary septa within the
polyparium, appears displaced towards the polyparium’s concave
side. This phenomenon is no doubt due to retardation of development
on the concave side, as though under the influence of contraction of
the coral here at its curved part; on the convex side, on the other
TEXT-FIG. 4.—Diagrammatic sections of Lophophyllum proliferum, McChesney-
The section on the left is a Russian and on the right an American
specimen. In both cases the upper side of the section is on the convex
side of the polyparium (after Yakovlev & Duerden, 1903). H, G, S,
Main, Counter, and Alar septa respectively. S;, the fourth pair of primary
septa. a, b, secondary septa. % nat. size.
hand, the development is accelerated, as though under the influence
of distention.
Colonial Rugosa are characterized by intracalicinal budding,
resulting in a bush-like appearance, and causing a limited growth of
the colony. Hexacorals, on the other hand, multiply by division and
build colonies which spread far from their initial point on the
surface of the substratum. Colonial Rugosa also differ from Hexa-
corals in the greater size of their individual corallites. The Rugosa,
consequently, do not possess the plasticity necessary for producing
the variety of colonial forms that we find among the Hexacorals,
e.g. Madrepora. ‘lo the small dimensions of the colonies and to the
monotony of form probably was due the small share they took in
building Paleozoic reefs.
The Rugosa became extinct at the close of Paleozoic time, probably
in consequence of an unfavourable environment, which may have
7
ae
ie
pie
yyy:
Wake
io.
~
Grou. Maa., 1917. Prate VIII.
2 t
LATERAL ATTACHMENT OF RUGOSE CORALS.
A. Holines—Classification of Igneous Rocks. 115
been due to the following causes. The end of Paleozoic time coineides
with a worldwide period of mountain-building—the period of the
so-called Appalachian revolution of American authors, and that of
the building of the Ural and Donetz ranges of Russia (where the
change of facies is surprisingly abrupt—the limestone strata of
the Upper Carboniferous giving way to the Permo-Carboniferous
characterized by great expanses of sandstones). When the limestones,
laid down in shallow and comparatively calm waters, were deposited,
the environment was favourable to the life of Rugosa Corals. But
the mountain-building uplifts, causing great quantities of clastic
material removed by denudation to be brought down and deposited
in the sea, created conditions the reverse of favourable to the corals.
In the Permo-Carboniferous the Rugosa are already rare, and after
that time are extinct; and nearly the same fate befel the Tabulate
corals. When suitable conditions again arrived, a new race of corals
arose—the Hexacorals—replacing the Rugosa.
The above explanation of the organization of the Rugese Corals
results from considering the simple primary factors of morphogenesis.
I think that it is only for such simply organized animals as the
Coelenterata that such a complete and harmonious explanation is
possible; and that it is not possible to give an all-embracing
expression, reduced to a mathematical formula, of the strueture of
higher animals, because of their complex organization. In a few
cases, however, such expressions have been found for isolated organs
_of higher animals; for instance, in the case of the development of the
feet and teeth of Vertebrates.
EXPLANATION OF PLATE VIII.
THE LATERAL ATTACHMENT OF RUGOSE CORALS.
Fie. 1.—Cyathophyllwm ceratites, Goldfuss, attached to a branch of C. cespi-
tosum, Goldfuss. Devonian: Timan Range, River Uehta.
», 2.—Pseudocaninia conica (Fischer de Waldheim), attached to a spine of
Archeocidaris. Upper Carboniferous: Mjatshkovo village, Govern-
ment of Moscow. ;
», 3.—Petraia permiana, Nechaev, attached to the dorsal valve of Stropha-
losia. Permian :. Gorodistshe village, Government of Vjatka.
A. V. Nechaev’s specimen.
», 4.—Cyathophyllum heterophyllum, Edwards & Haime, attached by a
highly developed, sole-like appendage. Devonian: Paffrath,
Rhenish Prussia.
IV.—A Mrwneratoeicat Crassirication oF Igneous Rocks.
By ARTHUR HOLMES, A.R.C.S., D.1.C., B.Se., F.G.S.
| URING the past two years the teaching collection of rocks in the
Geologival Department of the Imperial College has been under
re-arrangement, and in the course of the work the writer has had
occasion to consider very carefully the principles on which igneous
rocks should be classified. He is aware that in the present state of
our knowledge any such classification must be tentative and experi-
mental. and should be judged according to its general convenience,
both for teaching purposes and for understanding the various problems
that arise from petrological studies. The following article summarizes
116 =A. Holmes—Classification of Igneous Rocks.
the conclusions arrived at, and while the writer must be held entirely
responsible for all expression of opinion, he wishes to acknowledge
his gratitude and indebtedness to Professor Watts and Dr. Evans,
both of whom, in numerous discussions, have freely offered suggestions
and criticism which have proved to be of the greatest value.
In recent years the chief criteria on which systematic classifications
of igneous rocks have been based are (a) mineral composition,
(d) chemical composition, and (¢) texture, or (c’) mode of occurrence
(Cross, 1910, p. 473). Although the two latter factors have often been
considered interdependent, it is now becoming generally recognized
that they are by no means wholly so, and modern custom tends more
and more to relegate each of them toa subsidiary position in classifica-
tion. For the working petrologist, the mineral composition of an
igneous rock is, in a great majority of cases, its most important
characteristic. Unfortunately, many minerals, such asthe pyroxenes
and amphiboles, are capable of a wide range in composition. More-
over, a small percentage of igneous rocks are incompletely crystallized.
It has therefore to be recognized, and accepted as at present an
unavoidable limitation, that the whole field of igneous rocks cannot be
reliably classified on a mineralogical basis that will also faithfully
reflect the chemical composition. On the other hand, a chemical
classification, whether founded on normative minerals, or otherwise,
demands far more analyses than can in practice be obtained. In
addition to the requirements of field-work, it is therefore necessary
to have at least two systems of classification, one mineral, the other
chemical. Clearly, for purposes of comparison, the two systems
should be arranged as closely as possible along parallel lines.
In the Quantitative Classification of Cross, Iddings, Pirsson, and
Washington, the chemical composition is expressed, not in oxides,
but by a series of standard minerals known as the norm, as opposed to
the mode, which is the actual mineral composition. ‘he first division,
into Classes, is based on the relative proportions of the salve and femic
groups of minerals in the norm (corresponding terms for the mode are
felsic and mafic). As Mr. G: W. Tyrrell (p. 63) has pointed out, the
five classes that are adopted correspond in principle, though in
greater detail, to Brogger’s division of igneous rocks into leucoeratic
and melanocratic types.
The second division, into Orders, is based in the first three classes
on the ratio of quartz, or if quartz be absent of felspathoid, to
felspar. he orders thus correspond partially to Professor Shand’s
division of igneous rocks into oversaturated, saturated, and under-
saturated types (1918, p. 518, and 1915, p. 340). One of the most
serious defects of the C.I.P. W. Classification, to which attention was
drawn by Tyrrell in 1914 (p. 68), lies in the fact that the method of
subdivision into orders in Classes IV and V is based on ratios of the
femic minerals, thereby introducing a most confusing break and lack of
parallelism between the subdivisions of Classes I to III, and those of
TVand VY. - Tyrrell urges that the salic divisions should ‘be carried on
through all the classes and for the same reason the femic divisions
of the later classes might, if desired, be carried back through the
early classes,. thus providing each rock analysed with a double symbol.
A. Holmes—Classification of Igneous Rocks. Tay)
It also seems to the present writer that Order 5, embracing as it does
rocks with normative quartz and felspar, felspar alone, or felspar and
felspathoid, is of too broad a character. It traverses one of the few
natural lines of distinction available for classification, the line between
the antipathetic minerals quartz and felspathoid. Certainly the
norm indicates which of these is present, but in the symbol it might
advantageously be expressed by suffixes such as the following :—
5q (accessory normative quartz present),
5 (no quartz nor felspathoid present; in this case normative olivine would
generally be present),
5, (accessory felspathoid, or lenad, present).
The division of orders (of Classes I to III) into Fangs is based
on the ratio of the molecular proportions of alkalies to lime, only
those ehtering into the salic minerals being employed for comparison.
Mineralogically, this is practically the ratio of orthoclase plus
albite to anorthite, it being understood that felspathoids, where
present, are to be expressed in terms of the amounts of orthoclase
and albite to which they are equivalent. The ratio, however, tells
us very little about the rock to which it is applied beyond expressing
in a general way its alkalicorcalcic character. It issuggested below
that a more useful method of division would be afforded by the ratio
of the molecular proportions of soda to lime in the felspars, or better,
of the direct ratio by weight of albite to anorthite. Such a ratio
would express the normative soda-lime felspar, and in many cases the
latter would not materially differ from the actual soda-lime felspar
of the rock.
The division of rangs into Sub-rangs is based on the molecular
ratio of salic potash to salic soda, and is useful in distinguishing
rocks with minerals like orthoclase, muscovite, leucite, and biotite,
from those containing albite, analcime, nepheline, ete.
It has frequently been a matter for surprise that the sub-rangs of
the C.I.P. W. Classification (of which in the first three classes there
are 675) do not always contain rocks of closely similar types, and that
adjacent sub-rangs may sometimes enclose rocks that are much more
closely related to one another than they may be to other rocks falling
within their own sub-rang. The latter possibility is illustrated by
the following analyses, taken from Iddings’ Jgneous Rocks, vol. i1:—
A. 1B C. D. EK.
SiQg . 75-04 75:17 74-37 73-05 64-57
AleO3 .. 13-12 12-66 13-12 14-67 16-80
Fes O3 5 2-12 0-23 0:73 0-89 0:97.
FeO : n.d. 1-40 0-87 n.d. 3:02
MgO . 0-34 0-05 0-35 0:26 1-69
CaO... 0-40 0-82 1-26 0-97 3°53
Na,O . 2-44 2-88 2-57 3-99 3-81
K,0 : 6-32 5-75 6-09 5-11 4-01
H.0 0:76 0-82 0-30 0-91 1-28
ihaglls >, — O47 0-45 — = _
Total . 100-54 100-26 100-11 99-85 99-68
Symbol: 1,4,1,2 I, 4,1,3 I, 4, 2,3 I, 4,2,3 I, 4, 2,3
Omeose. lLiparose. Toscanose. Toscanose. Toscanose.
118
Cal@raes 4 3) 2 1 K20
In the above diagram the rectangular spaces represent subdivisions of the
C.1.P.W. Classification formed by ranges and sub-rangs. The spaces between
the curved lines represent the distribution of the different soda-lime felspars
across the C.I.P.W. Classification in Classes I-III, Orders 1-4 and part of 5.
In the case of other orders, the curves occupy other positions which may be
obtained approximately by swinging them upwards about the north-east corner
through an angle depending on the amount of felspathoid present in the norm.
Actually, the classification is, as generally used, in four dimen-
sions, and consequently sixteen sub-rangs meet in the theoretical
point determined by the intersection of four super-planes. Thus it
would be possible for sixteen closely similar analyses to fall into
sixteen adjacent pigeonholes, whereas sixteen analyses distributed
evenly through any one of the pigeonholes would show considerably
more variation. Obviously, this is not a serious fault in the
classification unless it can be shown that there is a natural grouping
of rocks. If there were, and the existing modal nomenclature is
A. Holmes—Classification of Igneous Rocks. 119
I.
OVERSATURATED ROCKS: CHARACTERIZED BY QUARTZ.
Org SODA Orig.s ROCKS. Ors7.; SODA-POTASH ROCKS. Orgo.5 POTASH Org7.5 ROCKS. Orjoo
ALBITR.
OLIGOCLASE-
ANDESINE.
LABRADORITE- =
ANORTHITE. §
&
3
Felspar absent
or accessory.
SODA-GRANITE.
Rockallite.
PEGMATITE.
SODA-POTASH GRANITE. POTASH-GRANITE.
Hkerite. Muscoyite granite.
Grorudite. Muscovite biotite granite.
PEGMATITE. PEGMATITE.
Granophyre.
SODA-QUARTZ PORPHYRY|SODA-POTASH Q. PORPHYRY| POTASH QUARTZ PORPHYRY.
Quartz bostonite. Aplite.
Paisanite.
SODA RHYOLITE.
Comendite and Pantellerite.
SODA-POTASH RHYOLITE. POTASH RHYOLITE.
QUARTZ- GRANO-
DIORITE. DIORITE.
Tonalite. 5
ADAMELLITE. GRANITE.
Quartz monzonite. Biotite-granite.
Hornblende granite.
Augite granite, etc.
PEGMATITE.
Granophyre.
QUARTZ PORPHYRITE. QUARTZ PORPHYRY.
Nevadite.
Aplite.
DACITE. RHYO-DACITE. RHYOLITE.
/ Quartz latite. Liparite.
Dellenite.
QUARTZ GABBRO. QUARTZ MONZONITE (in part). Labradorite
Quartz anorthosite.
‘Quartz norite.
QUARTZ DOLERITE.
Quartz diabase.
QUARTZ BASALT.
Bandaite.
granite.
QUARTZ TRACHY-DOLERITE.
QUARTZ PYROXENITE.
Quartz hornblendite.
120 )
S
Ss
Felspar:
absent or
ACCESSOry.
Felspar
absent.
OLIVINE ALKALI-SYENITES.
Laurvikite (in part).
Rhomb-porphyry (in part).
OLIVINE-ALKALI-TRACHYTES.
Skomerite.
Olivine kenyte.
|
OLIVINE DIORITE.
OLIVINE ANDESITE.
Mugearite.
OLIVINE GABBRO.
Olivine anorthosite.
Olivine norite.
Olivine hyperite.
OLIVINE DOLERITE.
Olivine diabase.
OLIVINE BASALT.
OLIVINE MONZONITE !
(in part?).
OLIVINE TRACHY-
ANDESITE.
Olivine latite.
OLIVINE MONZONITE.
Kentallenite.
Absarokite.
OLIVINE TRACHY-DOLERITE.
Ciminite.
PICRITE.
Olivine pyroxenite.
LIMBURGITE.
Picrite-basalt.
PERIDOTITE.
Wehrlite.
Lherzolite.
Cortlandite.
Dunite.
MICA-PERIDOTITE.
Kimberlite.
1 See footnote on p. 121.
124
=)
or
rc)
LABRADORITE-
ANORTHITE.
“ Anioo
Felspar absent.
or accessory.
NEPHELINE SYENITE.
Mariupolite. Laurdalite. Borolanite.
Foyaite, Ditroite. : Leucite syenite.
Litchfieldite.
Covite.
Kudialite syenite.
Shonkinite. Leucite shonkinite.
NEPHELINE-SYENITE PORPHYRY.
Tinguaite porphyry.
Tinguaite.
NEPHELINE PHONOLITE. LEUCITE PHONOLITE.
ESSEXITE (in part).
Shonkinite (in part). Marosite.
Vicoite.
Kulaite (in part). |
THERALITE. |
Essexite (in part). Nepheline monzonite.
TESCHENITE.
Analeime dolerite.
Camptonite (in part). |
NEPHELINE TEPHRITE.| LEUCITE TEPHRITE.
Analcime tephrite. Kulaite (in part).
IJOLITE.
Jacupirangite.
Bekinkinite.
MONCHIQUITE (olivine LEUCITE MONCHIQUITE (olivine free).
free).
Fourchite. Ouachitite.
Nepheline monchiquite
NEPHELINITE. LEUCITITE.
126 A. Holmes—Classification of Igneous Rocks.
three divisions are necessary, those corresponding to albite (up
to ANj5), to oligoclase and andesine (from An), to An;9), and to
labradorite to anorthite (from Ansy to Anjoo). Symmetry seems to
demand an anorthite division, and in some cases it would be useful
to distinguish oligoclase rocks. Probably the five rang divisions of
the soda-lime felspars would give somewhat better results, the present
objection to using them being merely the lack of an appropriate
nomenclature. In particular, the boundary between andesine and
labradorite at An, is preferable to that at An, ). However, these
are extensions of the method which will fall naturally into place as
more rocks are quantitatively examined and described.
Secondly, it is proposed to divide the rocks further according to
the ratio of orthoclase to albite, or, stating it more generally, according
to the molecular ratio of potash to soda. The ratio is conveniently
expressed by the percentage of orthoclase in total orthoclase plus
albite. In order to give the felspathoid minerals and the micas due
weight in the classification, these may also be expressed in terms of
the amounts of orthoclase and albite to which they are approximately
equivalent. The chief factors required for this conversion are given
approximately in the following table :—
ORTHOCLASE=1°0 ALBITE =1°'0
Anorthoclase = 0°4 Anorthoclase =0°6
Leucite =1°4 Analeime = 5
Muscovite =0°7 Nepheline =1°6
Biotite =0°6
Some petrologists may object to the inclusion of biotite as a mineral
comparable to orthoclase, but since it may be regarded as containing
a leucite-like molecule, it seems desirable to take it into considera-
tion. The writer is aware that at this stage the classification ceases
to be purely mineralogical, but it is difficult to avoid some such
grouping of minerals if the classification is to be one that can readily
be tabulated and memorized. To employ every important mineral as
a classificatory co-ordinate would demand more dimensions than can
be printed or mentally visualized. The point raised touches the
question of the objects of the classification, and these may be stated
as follows :—
(a) To attain parallelism with a chemical classification as far as
possible.
(6) To form compartments which shall largely define and limit
the types of rocks falling within them.
(c) 'To express the relations of rocks to one another ; linear in
a chemical and mineralogical sense, and genetic as far as this can be
done by a division of space into compartments.
(d) To enable students of the subject oye to memorize the ever
increasing list of rock names.
(e) To indicate to petrologists where new names are necessary, and
where they may, with advantage, be avoided.
Returning from this digression to a consideration of the actual
subdivisions adopted on a potash to soda basis, we may consider
those that have already been used. In the C.1.P.W. Classification
the five sub-rangs would give limiting positions at Or,.;—Ors7.;—Or¢2.s—
A. Holmes—Classification of Igneous Rocks.
V
27
UNDERSATURATED ROCKS: CHARACTERIZED BY FELSPATHOIDS AND
OLIVINE.
Oro SODA Orjo.s ROCKS. Org7.; SODA-POTASH ROCKS. Org.; POTASH Ofg7.5 ROCKS. Oriog
ALBITE.
ba
=)
x
OLIGOCLASE-
ANDESINE.
>
ee
S
LABRADORITE-
ANORTHITE.
Ani00
Felspar absent
or accessory.
OLIVINE ESSEXITE
(in part). Olivine shonkinite.
OLIVINE THERALITE. SOMMAITE.
Olivine essexite (in
‘ part).
OLIVINE TESCHENITE.
; Olivine camptonite (in part).
NEPHELINE BASANITE. LEUCITE BASANITE.
Olivine kulaite.
Olivine jacupirangite.
Olivine bekinkinite.
OLIVINE MONCHIQUITE. LEUCITE OLIVINE MONCHIQUITE.
Missourite.
Alnoite.
NEPELINE BASALT. LEUCITE BASALT.
Nepheline melilite
basalt.
Melilite basalt.
128 A. Holmes—Classification of Igneous Rocks.
Ory,.;, Some authors have used 1/3—2/3 (Or;s—-Or,,) as the limiting
ratios of orthoclase to total felspar in certain groups of rocks such
as monzonite (Hatch, 1916, vol. i, p. 192). This procedure,
however, compares orthoclase to soda-lime felspar, and as the
composition of the latter varies according to its occurrence in (say)
granites or gabbros, adamellites or labradorite-monzonites, it follows
that the same factors are not used throughout. Iddings in his modal
classification (vol. ii) adopts 3/8-5/8 as limiting ratios, with a still
greater possibility of variation in the factors, since for orthoclase
he substitutes alkali felspar.
Until we know whether there be a natural grouping of rock types
about certain points (and relative abundance of the types concerned
must, of course, be the chief test applied), the precise value of the
limiting ratios adopted does not seriously matter. Those here
employed are the ratios of the C.I.P.W. Classification, using in
general only three of the five divisions. The separation of grano-
diorite from quartz-diorite and adamellite demands a fourth sub-
division. According to the definition of Lindgren, the orthoclase
limits for granodiorite are about Or,) — Orgs, consequently the C.I.P. W.
limits Or,).;—Ors,., will serve equally well. In the other direction,
a fifth subdivision is necessary to accommodate the labradorite-
monzonites which, starting at Or.,;, may be allowed to pass over
the Org, dividing-line as far as the Or,,; limit. These limits are
broader than are actually required, but as they do no violence to the
definition of a gabbro, there can be no objection to their adoption.
The writer does not wish to insist on rigidly fixed lines of division,
for it is his opinion that a really valuable quantitative classification
can only emerge when thousands of modes have been measured and
statistically examined. ‘The mode is the only ‘“‘symbol”’ that can at
present usefully be given to a rock. Nevertheless, for a tabular
statement to be possible at all, lines must be drawn somewhere, and
those adopted seem to enclose all accepted rock names without
changing their current significance.
There remain to be considered rocks without actual felspar.
Logically, the five divisions here made on successive pages should be *
repeated for rocks free from felspar, the divisions giving in respective
order: Quartz rocks, Pyroxenites and Hornblendites, Peridotites,
Felspathoid rocks, and Olivine-felspathoid rocks. It is much more
convenient, however, to treat each group as a limiting case of the
felspar group to which it most clearly belongs. This is done in
the tabulation by placing some of the rocks in question below
the corresponding felspathic rocks.
In each division of the tabular scheme, the coarse-grained rocks
(eneially those of major intrusions, to use Dr. Evans’ convenient
term for ‘ plutonic’ masses) are used as types, and allied porphyritic,
fine-grained, or aphanitic varieties (belonging generally to minor
intrusions and lava-flows) are grouped with them.
The classification is printed in three dimensions, in sheets super-
imposed one on another as required. Of these dimensions, the first
is based on degree of silica- saturation, and since it valnes lines of
variation from saturated types in the directions respectively of quartz,
A. Holives—Classification of Igneous Rocks. 129
felspathoid, and olivine, it really constitutes a classification on three
co-ordinates. to make quantitative’ divisions the ratios of quartz
to felspar, felspathoid to felspar, and of olivine to felspar or mafic
minerals, could be employed. In particular it should be pointed out
that in the table of oversaturated rocks, quartz-syenites have been
squeezed out by the granites, and only consideration for space has
deterred the writer from inserting a second sheet to include rocks
with small amounts of quartz (on which such rocks as quartz-gabbro
would then have properly appeared). The fourth and fifth co-
ordinates, printed as second and third dimensions, are quantitative,
and depend respectively on the ratios of albite to anorthite (expressed
by percentages of anorthite), and of orthoclase (including other
potash minerals suitably weighted) to albite (including other felsic
soda minerals suitably weighted). A remaining feature, unexpressed
in the tables, is the ratio of felsic to mafic minerals. The classification
and nomenclature arising from this ratio have already been described ;
and in practice the ratio constitutes a sixth co-ordinate that may
often be of great service as a further means of subdivision. The
seventh and last co-ordinate is textural.
Vogt (see Harker, p.373) has pointed out that in the peridotites
the atomic ratio of magnesium to iron gradually increases as the
amount of alumina decreases. Dr. Prior has also used the ratio of
Mg 0O/FeO with excellent results in a recent and illuminating
classification of meteorites (Ain. Mag., p. 42, 1916). It may be
worthy of notice that in the mineralogical classification of this
paper, the same ratio increases from the north-east corner of each
sheet to the south-west corner, for rocks having a normal ‘colour
ratio”’ or felsic/mafic ratio. Indeed, for all such rocks (as far as
can be tested by ‘‘average”’ analyses) the chemical variation in any
direction is approximately regular.
Glassy rocks are necessarily incapable of treatment, as indeed
they must be by any system of classification by minerals. Similarly,
most, altered rocks, whether they be altered by pneumatolytic or
other processes arising from the consolidation of their parent magma,
or by weathering processes, must also be excluded. A classification
appropriate to express their characters would be based on the
processes by which they have been.altered, and the mineral and
structural changes whereby their new features have been developed.
REFERENCES.
CROSS, Tones! PIRSSON, & WASHINGTON. ‘‘ Quantitative Classification of
Teneous Rocks”? - Journ. Geol., x, p. 555, 1902. In book form, 1903.
5 Modifications of the Quantitative System”? : Journ. Geol., xx, p. 550, 1912.
Cross, W. ‘“‘ The Natural Classification of Igneous Rocks’’: Q.J.G.S., Ixvi,
p- 470, 1910.
““The Use of Symbols in expressing the Quantitative Classification ”’
Journ. Geol., xx, p. 758, 1912.
“Problems of Petrographic Clas-ification’’: Journ. Geol., xxii, p. 791, 1914.
Evans, J. W. ‘‘ The Quantitative Classification of Igneous Rocks ’’: Science
Progress, No. 2, October, p. 258, 1906.
HARKER, A. The Natural History of Igneous Rocks, ch. xv, 1909.
Hatcu, F. H. ‘‘ The Classification of the Plutonic Rocks’’: Science Progress,
No. 10, October, 1908.
Text Book of Petrology, vol. i, 1916.
DECADE VI.—VOL. IV.—NO. III. 9
130 Reviews—Thrust Movements in Norway.
IDDINGS, J. P. Igneous Rocks, vol. i, 1909; vol. ii, 1913.
LINDGREN, W. Amer. Journ. Sci., ix, p. 269, 1900.
SHAND, S.J. ‘‘On Saturated and Unsaturated Igneous Rocks’’ : GEOL. MAG.,
(V) X, p. 508, 1913 ; (VI) I, p. 485, 1914; (VI) II, p. 339, 1915.
‘“A Recording Micrometer for Geometrical Rock Analysis’’: Journ Geol.,
xxiv, p. 394, 1916.
TYRRELL, G. W. ‘‘A Review of Igneous Rock Classification’’: Science
Progress, No. 33, p. 60, July, 1914.
REVIEWS.
I.—New Lieur on THE Careponran Tarust Movements 1n Norway.
Vor IV, part i, of the Norsk Geologisk Tidsskrift, just published,
contains a summary of an exceptionally interesting paper on
the tectonics and formation of the Norwegian mountains, read before
the Geological Society of Norway by Professor V. M. Goldschmidt,
of Christiania University.’ As the Norwegian and Scottish Highland
rocks are of similar age and nature and exhibit the same type of
tectonic structure, the discoveries in one region cannot fail to be of
interest to the workers in the other: the chief points of the paper
are here noticed without any attempt to offer criticism. The main
conclusions advanced are of a novel character and have more than
a local significance, for the author uses them to elucidate the problems
offered by the rocks and structures of other great mountain ranges of
the world.
The paper deals with the central Norwegian mountain region in
which great masses of eruptive gabbro and granite have been thrust
over Ordovician phyllites. A series of arkoses, conglomerates, and
schists, known as the ‘“‘ Hoifjeldskvarts”’ (high-mountain quartz) is
usually present overlying the phyllites, and an attempt is made to
elucidate the hitherto problematical origin and age of the series, to
show its relationship to the high mountain eruptives which frequently
overlie it, and to demonstrate the conditions under which the
Caledonian mountain-building thrust movements obtained. The
great difficulty experienced in unravelling the nature and origin of
the ‘‘ Heifjeldskvarts’’ results from the extreme metamorphism to
which a great part of ithas been subjected. Thus, if it were possible
to classify its green schists and determine their origin, much light
would be thrown on many problems, but as yet there is no means of
doing this, for a tuff, an agglomerate, a conglomerate, an effusive or
intrusive mass may all on alteration give the same kind of amphibolite
schist. A district was therefore chosen for investigation in which
the regional metamorphism is.a minimum, and there are fewest
hindrances in the way of an indisputable identification of the rocks.
Such a district was found in Central Norway to the east and west of
Valdres, north-west from Christiania. .
In the first tract discussed, that between Valdres and Gudbrandsdal,
the sedimentary origin of the ‘‘ Heifjeldskvarts”’ can be established
beyond doubt. The series here occupies an extensive area, and
1 VY. M. Goldschmidt, ‘‘ Om heifjeldskvartsen I og If’’: Norsk Geologisk
Tidsskrift, Bd. iv, Hefte i, pp. 44-6, 49-53, Kristiania, 1916.
Reviews—Thrust Movements in Norway. 131
interbedded in it are conglomerates essentially composed of gabbroid
stones. ‘The problem is to determine the relationship of these
conglomerates to some adjacent gabbro mountain masses which owe
their present position to thrusting. In an early paper Bjerlykke
held that the conglomerate was derived from the gabbro, and was
thus the younger ‘formation. In a later communication, however,
the contrary opinion is expressed that the gabbro is younger than the
‘‘ Heifjeldskvarts’’, and was intruded between it and the underlying
phyllites. Professor Goldschmidt has made a thorough microscopic
investigation of these rocks. The massive gabbro is a very characteristic
rock composed of very fresh augite, less fresh biotite, and a wholly
decomposed plagioclase ; hor nblende varieties also occur. The pebbles
of the conglomerate exhibit all the varieties of the massive mountain
gabbro, from which they are clearly derived. Thus the ‘ Heif-
jeldskvarts”’ cannot be older than the mountain-building movements,
since these conglomerates were laid down after the gabbro masses
had reached their present position. Again, the conglomerate can be
followed to places where it is overlaid by the gabbro and has been
strongly pressed, often almost out of recognition. Thus the ‘‘ Hoifjelds-
kvarts”’ cannot be younger than the thrusting movements, seeing it
has been metamorphosed during, and as a result of, their evolution.
It is not pre-Caledonian ; it is not post-Caledonian ; it is Caledonian
—a conclusion of great significance, for it shows that the thrusting
took place at the earth’s surface, a conglomerate being laid down
during the process. The gabbro was eroded in front, whilst it was
being “pushed forward from behind.
The second tract examined lies between Valdres and Hemsedal.
Here we have a similar type of structure, only the Ordovician
phyllites are overlaid by thrust masses of granite instead of gabbro.
In the south of the district the conglomerate beds are seen overlying
the granite as a normal basal deposit, with no evidences of pressure
action. In the north, on the other hand, the conglomerate has been
overridden by the eranite, and its pebbles lave been pressed and
drawn out by the movement. Here also the derivation of much of
the conglomerate from the granite which now overlies it is established.
Thus the investigations in both of these districts lead to the
conclusion that the sedimentation of the ‘‘ Hoeifjeldskvarts”’ took
place whilst the great eruptive masses were being driven forward,
and with deposition of material from the erosion of the selfsame
masses. By the continuance of the thrusting movements the
sediments were covered and metamor phosed. On this interpretation,
and in opposition to the orthodox view that the great thrust move-
ments have obtained at a considerable depth, it must be admitted
that great mass-thrusting can take place ‘“‘in daylight”? at the
surface, so that a mass can be driven forward and be subject to
erosion at one and the same time, in such a way as to ride over its
own debris. After mentioning the great amount of work which yet
remains to be done before all the problems of the ‘‘ Hoifjeldskvarts
can be solved, and the flood of light which a full understanding of
this series must throw not only on the formation of the Norwegian
mountains but on the general principles of tectonic geology, it is
1382 Reviews—Cretaceous Brachiopoda, West Africa.
confidently affirmed that ‘‘ the old dogma limiting the great thrust
movements to a great depth stands no more”’.
Professor Goldschmidt parallels the Flysch with the ‘‘ Heifjelds-
kvarts’”’ formation. Just as the ‘‘ Heifjeldskvarts”’ is Caledonian,
so the Flysch is Alpine in age, being formed contemporaneously with
the mountain - building movements, though the petrographical
similarity between the two formations is very small, one obtaining
its material from forward-thrust eruptives and the other from forward-
thrust Mesozoic sediments. In the discussion following the reading
of the paper Professor Brogger expressed his approval of the original
views set forth, and the further work of the Norwegian geologists in
the light of the new theory will be followed with great interest.
L. Hawxrs.
I{.—Own somre Cretacrous Bracutopopa anp Motiusca From ANGOLA,
PortuguEsE Wusr Arrica. By R. Burten Newron. ‘Trans.
Royal Soc. Edinburgh, vol. li, pt. i, No. 15, August, 1916.
[J\HE fossils described in this paper were collected by Professor
J. W. Gregory and Mr. E. Robins from a cream -coloured
limestone in the neighbourhood of Lobito Bay, north of Benguella in
Angola. Most of the specimens are poorly preserved, but the author
considers that there is sufficient evidence to refer the fauna to the
Vraconnian stage, and this view receives support from the Cephalopods
which have been examined by Mr. G. C. Crick. Twenty species are
varieties only is of a purple-brown tint. A peculiarity of the olivine
basalts is their comparative richness in alkalies, a feature that brings
them into relationship with the titaniferous-olivine basalts of the
Western Mediterranean described and analysed by Washington.
The Arctic province, however, is distinguished by the abundance of
alkali-poor basalts, which in spite of the fact that their silica
percentages are low are thoroughly over-saturated rocks.
Professor H. Hilton: On the use of the Orthographic Projection
in Crystallography. The method of preparing a projection and its
use in the drawing of crystals were explained, and the advantages
of this projection of the sphere were pointed out.
J. V. Samojloff: Paleophysiology, the Organic Origin of some
Minerals occurring in Sedimentary Rocks. In connexion with the
exploration of the phosphate deposits of Russia, the occurrence of
barytes has been noted over a wide area in the governments of
Kostroma, Kazan, and Simbirsk, and also further to the north-east
in the basin of the Pechora River. The mineral occurs as nodules in
the clays and marls of the Upper Jurassic, and is confined to the
Oxfordian—Sequanian horizon, though extending up to the Kim-
meridgian in some of the districts. Nodules of barytes have been
dredged from the séa-floor off the coast of Ceylon, and granules of
barium sulphate have been detected in the bodies of certain marine
organisms, namely the Xenophyophora. If, therefore, during the
Upper Jurassic period such organisms, capable of extracting barium
salts from sea-water, were more abundant, they would account for the
accumulation of barium in these strata, where the barytes occur as
a primary mineral. Similarly, the mineral celestite has been found
over a very wide area in Turkestan in beds of Upper Cretaceous age.
The presence of strontium sulphate has been detected in the skeletons
of the Acantharia, a group of the Radiolaria. It is conceivable that
\
142 Reports & Proceedings—Edinburgh Geological Society.
similar organisms were relatively more abundant during the Cretaceous
period, and that their remains gave rise to the deposits of celestite.
Although the iron compound hemoglobin plays an important function
in the blood of present-day animals, yet cases are known amongst the
Crustacea and Mollusca in which the copper compound hemocyanin
performs the same function, and vanadium has been detected in the
blood of the Ascidia. During former periods of the earth’s history —
these, and perhaps some other, metals may have been predominant in
the blood of animals then living. In this connexion the persistent
occurrence in the Permian strata of copper minerals and ores associated
with abundant animal remains is significant. Similarly, there may
have been at different periods variations in the chemical composition
of the ash of plants. The recurring presence of minerals of primary
origin in certain sedimentary strata therefore suggests that there may
have been varying physiological processes during past periods, and for
this new branch of paleontology the name ‘‘ Paleophysiology”’ is
suggested.
E. S. Simpson: On Tapiolite in the Pilbara Gold-field, Western
Australia. The mineral, which was discovered at Tabba-Tabba
Creek and Greens Well, lying in a large area of granite intersected
_ by pegmatite veins and greenstone dykes and bosses, occurs in
fairly well-defined crystals, which analysis proved to contain little
niobium. At the first locality the crystals displayed the forms 100,
001, 111, 101, 320, and were twinned as usual on 101 and often
distorted; while at the second they displayed the forms 100, 111,
101, 520, and showed twinning about 106 and 301 as well as 101.
A curve was prepared showing the specific gravity obtaining in the
tetragonal isomorphous series of metatantalates and metaniobates of
iron, manganese, and calcium.
LV .—Epinpuren GEOLOGICAL SociEery.
January 17, 1917.—Dr. Flett, F.R.S8., President, in the Chair.
1. ‘‘Low-level Kettle-holes in and near Aberdeen.” By
Dr. Alexander Bremner. \
A number of kettle-holes, i.e. cup-shaped hollows due to the
melting out of isolated masses of ice embedded in fluvio-glacial and
morainic deposits, occur below the 100 ft. contour-line in the
Aberdeen district. During marine submergence such hollows could
not fail to be obliterated by wave action. Hence it may be inferred
that in this district (1) there was no 100 ft. submergence, or (2) the
submergence was anterior to or contemporary with the last advance of
the local ice.
2. “The Glacial Geology of the Stonehaven District.” By
Dr. Bremner.
The district dealt with extends westward from the coast between
Dunnottar Castle and Portlethen village to the Dee watershed and
south-westward to the Bervie Water from Drumlithie upward.
A description was given of the traces left by the ice which, in a phase
Correspondence—R. Bullen Newton. 143
of the Ice Age succeeding the maximum glaciation, flowed north-east
from Strathmore (Strathmore Ice), and of those left by the ice which,
after the final or partial disappearance of the Strathmore Ice from
the district, passed over the Dee watershed and brought with it a
characteristic ‘‘ granite drift’’ (Dee Valley Ice). Striation (E. 32°S.)
due to the latter ice was recorded from Beltcraig, near Portlethen.
Many peculiar valleys (glacial overflow channels) were noticed, the
largest being the gorge through which the Caledonian Railway
runs for fully a third of the distance between Drumlithie and
Stonehaven Stations.
It was pointed out that at Stonehaven, as at Aberdeen, no beach
deposits referable to the 100 ft. submergence have ever been
observed, but that there is strong evidence in favour of the existence
of a pre-glacial rock platform (now overlaid by glacial deposits) at
a level of 75 to 100 feet above O.D.
3. ‘Notes on River Development in the East-Central Highlands.”
By Dr. Bremner.
Many instances of rearrangement of drainage in the East-Central
Highlands were noted, and it was proved that in Sheets 64 and 65
there occurs no authentic case of recent (post-glacial) river capture ;
in particular, capture of the Slugain by the Quoich was shown to be
pre-glacial. (See also Scottish Geographical Magazine for November,
1915.)
The complicated history of the River Muick was traced in some
detail. By successive captures, its headwaters (Allt an Dubh Loch)
have been diverted from their original course down Glen Mark so as
to enter the Dee (1) by way of the Girnock Burn and the wind-gap
west of the Coyles of Muick, (2) by way of the present lower Muick.
The dismemberment of the original Tarf (Sheet 64) by the Bruar,
Tromie, and Edendon, and possibly by the Mhaire, was also discussed.
CORRERSPON DEHN CE.
a
FORAMINIFERAL LIMESTONES FROM NEW GUINEA.
Sir,— When reviewing the literature on some Foraminiferal lime-
stones from New Guinea, during the preparation of a paper published
in May last as No. 20 of a series of ‘‘ Reports on the Collections
made by the British Ornithologists’ Union Expedition and the
Wollaston Expedition in Dutch New Guinea, 1910-18”’, issued in
1916, I regret having overlooked an important contribution to the
subject by my friend Mr. Frederick Chapman, the paleontologist
of the National Museum at Melbourne, entitled ‘‘ Description of
a Limestone of Lower Miocene Age from Bootless Inlet, Papua”
(Journ. Proc. Roy. Soc. New South Wales, vol. xlviii, pp. 281—
301, pls. vii-ix, 1914-15). The formsof Foraminifera referred to by
Mr. Chapman are almost identical with those mentioned in my report
as occurring in the limestones of Mount Carstensz, and, moreover,
the stratigraphical results are exactly similar in each case. It is
144 Correspondence—J. B. Scrivenor.
interesting, therefore, to note that although these New Guinea
localities are so widely separated, being probably some 600 miles
apart, there is distinct paleontological proof that the limestones of
both regions belong to the later Aquitanian stage of the Miocene
epoch. It becomes increasingly difficult for the paleontologist to
keep pace with the vast amount of literature which is issued on
almost every branch of his subject, a condition of things which at
the present time is more than ever accentuated on account of the
Geological Society having discontinued the publication of their
annual list of ‘Geological Literature’’, which has been of such
inestimable service to all research workers in geological science.
R. Burten Newton.
BRITISH Musrum (Nat. Hist.),
SOUTH KENSINGTON.
FEDERATED MALAY STATES.
Sir,—Owing to the fact that copies of the Geological Society’s
Proceedings have not been sent to me while residing abroad I have
only just been made aware, by the appearance of No. 284 of the
Quarterly Journal, that my name was unnecessarily introduced into
the Discussion on a paper read on June 23, 1915, p. 622 (but only now
printed and issued to Fellows, in February, 1917). The speaker,
Mr. W. R. Jones, said that :— ;
“The danger of examining ‘mountains under microscopes’ was illustrated
in a striking manner, in the case of a rock which occurs at the summit of
Gunong Bakau, in the Federated Malay States. This rock was described as
occurring extensively, and as being of no value. [A reference introducing my
name is given here.—J. B. S.] It was further stated that the rock was
evidence of the existence in this part of the granitic magma of a great quantity
of free hydrofluoric acid capable of attacking felspar without the precipitations
of a previously combined base, such as tin. Subsequently, however, the rock
was found to contain tin-ore, and it has now been worked on a considerable
seale.’’
As the Society’s officers have published the above I will ask you
to print the following brief reply.
The rock in question was not described as occurring extensively.
It was described as being of no value because neither the quartz nor
topaz was saleable. The passage concerning free HF omits any
reference to the following condition in my publication: ‘‘if indeed
it be correct to assume that the Chinchong rock is an alteration
product.”” Tin-ore has not been found in the rock. The rock has
not been worked.
The speaker’s imperfect knowledge of the locality and failure to
digest the page of my publication that he quotes have made him
oblivious of dangers greater than that which he describes.
J. B. Scrivenor.
““A?? COMPANY, INNS OF CouRT O.T.C.,
BERKHAMSTED.
February 2, 1917.
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WEST (G.). », A-T,. i manonia. Portsdown, Hants.
oy ett a transligata. Coltishall, Norfolk.
mt - Vf Trimingham.
», LO-12. Se pyramidalis. i
Il.—On tue Inrecument or J@UANODON BERNISSARTENSIS, BOULENGER,
AND oF J/OROSAURUS BECKLESI, MANTELL.
By REGINALD WALTER HOoo.ey, F.G.S.
(PLATE X.)
InTEGUMENT OF [GUANODON BERNISSARTENSIS.
(Y\HE Zguanodon has been known since 1825, when the genus was
first described from teeth by Mantell.! Odd bones and various
associated portions of the skeleton have been found in England, and
in 1878 the skeletons of many individuals were discovered in the
Wealden of Bernissart, near Mons, Belgium.
No trace of the dermal covering has hitherto been observed. Owen?
in 1885, when describing the bones of a ‘‘ young Jguanodon”’ from
the Wealden of the Isle of Wight, mentions that ‘‘some portions of
a layer of dark finely granulated carbonaceous matter were found
embedded between the ribs, near the middle of the side of the trunk ”’,
which he queried as the integument of Jyuanodon, but these remains
were proved later to belong to Hypsilophodon.
In 1914 I obtained from the Wealden Shales of Brighstone Bay,
Isle of Wight, nearly the entire skeleton of a young individual of
Iguanodon bernissartensis, with the exception of the greater part of
the tail. “4
In July last, while clearing away the matrix from the preacetabular
extremity of the left ilium, a portion of the epidermis (Fig. 1) was
exposed. It covers an area 90 mm. long by40mm.wide. The impression
of the integument is also discernible on another block 78 mm. long by
57 mm. wide, found in close proximity to the other. Fragments of
skin were also discovered underlying two of the left thoracic ribs.
On these latter specimens carbonaceous matter is to be seen. No
scutes or dermal ossifications were found. ‘he skin is remarkably
thin, and covered with small convex tubercles varying in diameter
from 5mm. to 3mm. On the largest specimen there is an area,
8 mm. by 7 mm., where the tubercles are slightly larger and flatter,
and 65 mm. distant occurs another patch with the same measurement,
where the tubercles coalesce in such a manner that the tuberculation
is almost invisible. The tubercles on the edge of the skin at the top
1 G. Mantell, Phil. Trans., 1825, p. 184.
2 R. Owen, Mon. Foss. Rept. Weald. Form., pt. ii, 1855, p. 51.
es
Grou. Mag., 1917. Pratze 1X.
R. M. Brydone, Photo. Bemrose, Collo.
Chalk Polyzoa.
R. W. Hooley—Integument of Wealden Dinosaurs. 149
of Fig. 1 are also decidedly larger and flatter than the others. One
plate-like tubercle, 10mm. in diameter, occurs on the smaller
portion of the skin from the same inguinal region. It appears
therefore probable that on those parts of the body exposed to the sun
large flat tubercles would be found as in Zrachodon annectens,' and it
is evident that the ‘‘ ground plan” of the epidermis is essentially
similar, consisting of small, rounded tubercles, although in Jguanodon
they are not so rounded or apical. Professor Osborn} thought that
the iguanodonts from the Lower Cretaceous of Kurope would probably
be distinct in their epidermal covering”’ from the trachodonts of the
Upper Cretaceous of America, and it is interesting to find that at
least they are alike in ground plan.
Intecument or Uforosaurus BeckiEsu, MantELLb=WL. Brevis, OWEN.
An impression of the epidermis of this reptile (Fig. 2) is well
displayed on a block of rock removed from the hollow between the
radial crest and the inner border of the left humerus. This humerus,
with the radius and ulna, was found in the Wealden beds of |
Hastings by 8S. H. Beckles in 1852. These specimens (No. R. 1870)
are now in the British Museum. They were referred to by Mantell
in a lecture given by him at the Royal Institution in that year.
The report” of the lecture records that ‘‘A portion of the scaly
cuirass which covered the limbs and is composed of hexagonal plates
was exhibited’’. he integument was also noticed by Marsh,* when
examining this fossil while still in the possession of its discoverer.
He remarks that he ‘‘found attached to the humerus portions of the
osseous dermal covering, the first detected in the Sauropoda, and
known only in the present specimen”. It has not been further
described, but by kind favour of Dr. A. Smith Woodward I am now
privileged to give the details.
The side of the matrix upon which the epidermal markings are
shown is convex, well seen in Fig. 2, but this feature is entirely due
to the concavity of the partieular) area of the humerus upon which it
lay and not to the natural rotundity of the limb. There was no
intervening matrix between the skin impression and the bone,
therefore unless this portion of the integument was turned inside out
after the decomposition of the muscles and before the matrix was
deposited upon it, the under surface of the epidermis is exhibited.
The only fact that supports the improbable theory of the reversal of
the integument is that there is an apparent ornamentation of very
small rounded tubercles displayed on some of the plates. The
smallest plates, especially at the upper end of the specimen, are
covered with them. It does not appear that they are due to
oxidization subsequent to the removal of the block from the humerus.
I have observed a somewhat similar result from chemical action after
exposure to the atmosphere on matrix which at first had a smooth
surface. However, it is more probable that they are papilliform
1H. Osborn, Mem. Amer. Mus. Nat. Hist., N.S., vol. i, pt. ii (June, 1912),
PP. 46, 47.
2 Proc, Roy. Inst., vol. i, p. 34, 1852.
2 0. C. Marsh, GEou. Mac. [3], pp. 205, 206, 1889.
150 A. Holmes & H. F. Harwood—Picrite, Mozambique.
protuberances of the epidermis into the dermis and that we are
looking upon the inner surface of the former.
There i is no sign of ossification, although Marsh* speaks “ aE the
osseous dermal covering’’. The extent of the epidermal impression is
210 mm. long by 200mm. wide. It consists of hexagonal plates,
convex and boss-like, which on their outer surface were probably
flat. A group comprising eight of the largest plates covers an area
95mm. long by 68 mm. wide. The central plate of this group has
a diameter of 26 mm. The plates surrounding this cluster gradually
decrease in size, until they are only 9mm. in diameter. The plates
do not overlap. The integument of MMorosaurus becklesit was
tuberculate and the lessening in dimensions of the tubercles towards
the axillary surface of the arm, where they probably became smaller
and rounded, is after the manner of Zrachodon and Jguanodon.
EXPLANATION OF PLATE X.
Fic. 1.—Impression of a portion of the epidermis from the left ilium of
Iguanodon bernissartensis obtained by the author from the Wealden
Shales of Brighstone Bay, Isle of Wight, in 1914.
», 2.—Impression of a portion of the epidermis of Morosaurus becklesi,
Mantell, found by Mr. S. H. Beckles in 1852 in the Wealden
beds of Hastings, now in the British Museum (No. R. 1870).
J1I.—Picrite rrom tae Ampwini River, MozamBigur.
By ARTHUR HotmgEs, A.R.C.S., D.I.C., B.Sc., F.G.S. (with an Analysis
by H. F. Harwoop, M.Sc., Ph.D.).
(PLATE XI.)
LMOST due west of Mozambique Island, at a distance of about
forty-two miles from the sea, the military road from Mosuril to
Nampula crosses the Ampwihi River, an important tributary of the
Monapo.? During the dry season the stream is reduced to a string
of stagnant pools, separated by long reaches of sand and- gravel
that here and there are interrupted by outcrops of the underlying
formations. Throughout the greater part of its course the Ampwihi
flows through a region in which gneisses persist with monotonous
regularity, the only variation being that due to oceasional intrusions
of granite and of still later pegmatite dykes. At the point where the
military road crosses the narrow channel a welcome diversion is
introduced by the presence of a dark compact dyke about 10 feet in
thickness. ‘he dyke appears on the right-hand bank and crosses
obliquely to the other side, taking a N. N.W.-S.8.E. course across
the strike of the older rocks. Upstream, about seventy yards to the
south-east, the Ampwihi bends to the south-west, so that it returns
towards the dyke, which is again exposed across its sandy floor. The
dyke was traced by Mr. E. J. Wayland in July, 1911, for a distance
of altogether 200 yards, and was examined by Mr. D. Alex. Wray
and later by myself during the same year. It is clearly the latest
1 Q. C. Marsh, op. cit., p. 206.
2 See A. Holmes & D. A. Wray, ‘‘ Mozambique: a Geographical Study ’’ :
Geog. Journ., p. 143, Aug. 1913 (Map, p. 112).
os Se
rae
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Grou. MaG., 1917. PWVATE NG
PORTIONS OF INTEGUMENT OF WHALDEN DINOSAURS.
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A. Holmes & H. F. Harwood—Picrite, Mozambique. 151
rock of the district, and is intruded along a line of fault, for in two
cases pegmatite dykes seen on the eastern side are broken across
and reappear on the western side with a well-marked northerly
displacement.
PETROGRAPHY.
The specimens collected were from the margin—evidently chilled—
of the transverse dyke, and have a dark-grey colour, mottled with
nearly black glassy phenocrysts of olivine. Here and there are
minute white amygdales, the infilling consisting of an isotropic
material that is probably glass. The weathered surface is creamy
grey in colour with rusty patches corresponding to the phenocrysts.
The average specific gravity of three fragments of the fresh rock
is 3:08.
In thin section the rock is found to consist of corroded phenocrysts
of olivine in a fine-grained groundmass composed mainly of elongated
grains of augite and enstatite, the former alternating with and
sometimes intergrown with laths of soda-lime felspar. In places
interstitial patches of pale brownish-grey glass appear, and where
a minute amygdale is seen it is found to be composed of the same
obscure material (Pl. XI, Fig. 1).
The olivine phenocrysts are occasionally hyp-idiomorphic in
outline, but generally they are deeply corroded, the resorption having
sometimes divided a large crystal into a number of rounded
fragments. Except around the edges and along cracks and cleavage
planes, where serpentinization has begun, the crystals are still quite
fresh. The serpentine is mainly of the fibrous variety, chrysolite,
the fibres being arranged normally to the edges or cracks from which
the alteration has developed. The only inclusions present are
sparsely scattered grains of magnetite. In one section it was noticed
that a shred of biotite had developed at the junction of an olivine
erystal with interstitial glass.
The most abundant mineral of the groundmass, and indeed of the
whole rock, is a pale yellow-green augite occurring in granules that
are generally slightly elongated along the c axis. ‘The average
refractive index is 1:7; the optic-axial angle is low; and the specific
gravity is nearer 3°2 than 3:1. These characters, when considered
in relation to the chemical composition of the rock, indicate that
the pyroxene approximates to the enstatite-augite variety.’
Among the augite granules there occur a few colourless grains
generally of similar average dimensions, but occasionally slightly
larger, having noticeably lower refractive index and double refraction,
and giving straight extinction. They were at first thought to be
wollastonite, but further optical examination showed that the optical
character is positive and that the average refractive index is about
1-67. These properties lead to the conclusion that the mineral is
enstatite. It is clear from its relations to the surrounding minerals
that it crystallized after olivine and before augite. In Pl. XI, Fig. 2,
a good example of enstatite can be seen adjoining the dark space on
the right-hand side.
1 See J. V. Elsden, Q.J.G.S., vol. lxiv, p. 287, 1908.
152 A. Holmes & H. F. Harwood—Picrite, Mozambique.
Between the grains of augite another colourless mineral, with
prismatic habit, occurs. The optical characters indicate that it is
a soda-lime felspar, approaching bytownite in composition. The
average refractive index is about 1°57, and the maximum extinction
angle is 40° measured from the direction of elongation of the
microliths. As the specific gravity is estimated to be about 2°73, the
composition of the felspar is approximately Abso Any, 1.e. that of
a caleic labradorite.
The relations between augite and felspar are illustrated in Pl. XI,
Fig. 2. A casual glance would suggest that the augite crystallized
before the felspar, but this appearance is due to the superior relief of
the augite, and a careful examination shows that the two minerals
crystallized together. This conclusion is corroborated by the fact
that in places a micrographic intergrowth can be detected. The
augite grains become more angular, and between them the minute
interstitial labradorite can be traced in optical continuity from place
to place. On the borders of the micrographic areas the felspar
frequently becomes fibrous and tends to radiate.’ Becoming gradually
more obscure the fibrous felspar dies away and an interstitial clearing
of glass appears. The refractive index of the glass is 1°55, and its
specific erawily is 2°5, indicating approximately the composts of
syenite.?
The relative proportions of the minerals were measured by the
Rosiwal method. Under a 1 in. objective the proportions of olivine and
groundmass were determined, and afterwards the groundmass was.
analysed under a} in. objective. As it was not found possible to
distinguish in every case between augite and enstatite, the two
pyroxenes were estimated together.
In order to determine the specific gravities of the various minerals,
a diffusion column of methylene iodide and methylene iodide diluted
with benzine was prepared so as to give a range from 3°38 to 2°3.
Olivine and magnetite sank. A well-marked band of pyroxene
formed between 3°1 and 3:2. Another band formed at 2°73
(labradorite), tailing out above and below owing to the difficulty of
obtaining a clean separation from such fine-grained material. Finally,
another layer formed at the level corresponding to 2°50.
The results obtained are as follows :—
Mineral Receaeo alae
Glass 3 2 8 2-50 a
Labradorite, ae F 17 2-73
Pyroxene . y : 45 3-15 (average)
Olivine . : : 29 3-45 (?)
Magnetite. : ‘ il 5-17 (?)
Total . . 100 Average . 3-20
The actual specific gravity of the rock is 3:08, so that the figure
assumed for olivine, 3-45, is probably a little too high. As the
1 See Iddings, Rock Minerals, 2nd ed., fig. 28, p. 215, 1911.
2 See J. A. Douglas, Q.J.G.S., vol. Isiii, p. 153, 1907, for relations between
refractive indices and specific eravities of glasses.
A. Holmes & H. F. Harwood—Picrite, Mozambique. 153
analysis indicates that the composition of the olivine includes nearly
80 per cent of forsterite, the specific gravity should be about 3:4.
This figure would give for the rock a calculated specific gravity of
8°10, which agrees more closely with the observed result.
CHEMICAL Composition.
An analysis of the rock was made by Dr. H. F. Harwood, with the
following results :—
Percentages. nee. PEE eee ates
SiO. . i 46-37 0-773
Al, O3 . : 10-82 0-106 Orthoclase . 3-33
Fe.O3 . ; 1-60 0-010 Albite . : 8-38
FeO . A 7-85 0-109 Anorthite . 23-33
MgO. i; 20-78 0-5195
CaO. : 7-94 0-142 Diopside . 12-82
Na,Q . 5 0-99 0-016 Enstatite . 16-41
K,O . : 0:57 0-006
H20+. 1-97 — Olivine . 380-30
H.,O-. f 0-82 —
CO.n . Z none — Magnetite . 2-44
Ni@ awe P 0-13 0-002 Ilmenite A 0-30
P2O5 . a none —
MnO . 5 0-16 0-002 97-36
Cr203 . 5 0-07 0-0005 Water . i 2-79
NiO. 5 0-07 0-001
Total . 100-14 ; ; Total . 100-16
Specific gravity (average of three specimens) = 3-08.
Radium content (A. H. 1915) = 0-44 x 10—™ grams per gram of rock.
The composition of the rock is of a type not very commonly found.
Its nearest analogue is that of a Hawaiian picrite-basalt which was
erupted in 1840.! A few other similar analyses are cited in the
table below (p. 154), from which it may be seen that two British rocks,
one from Anglesey and one from Loch Garabal, have a general
chemical similarity to the picrite under discussion. The presence of
nickel and chromium in every case in which it has been sought for is
an interesting feature, and indicates the importance of making
analyses as complete as possible. The association of these elements
with olivine-rich rocks has been frequently pointed out,” and there is
no doubt that by determining such relations in detail much may yet
be learned concerning the genesis of igneous rocks and ore-deposits.
Among African rocks the Mozambique picrite resembles most closely
some of the mineralized picrites of the Insizwa Range. Owing to
the presence of pyrrhotite and of copper and nickel sulphides in these
rocks the analyses cannot be directly compared, but it is clear that
1 W. Cross, Prof. Paper 88, U.S.G.S., 1916, pp. 44, 77. The mineralogical
composition of the Puna lava of 1840 is almost identical with that of the
Ampwihi picrite.
* H. S. Washington, Trans. Ann. Inst. Min. Eng., xxxix, p. 735, 1908.
> W. H. Goodchild, ‘‘ Economic Geology of the Insizwa Range’’: Inst.
Min. and Met. (read December 21, 1916).
154 A. Holmes & H. F. Harwood—Picrite, Mozambique.
the two rock-types are very similar. In one case (sample No. 7)
Mr. Goodchild remarks: ‘‘The felspars not infrequently show
micrographic intergrowth with the pyroxene, but on the whole are
interstitial,” and in the photo-micrograph of the rock (Fig. 9) it can
be seen that the correspondence in texture goes even further, for the
olivines are markedly porphyritic. From nickel-bearing rocks we
may turn to chromium-bearing rocks, as exemplified by those of the
Great Dyke of norite of Southern Rhodesia.’ Here, however, the
picrites are coarse-grained, and are not comparable in detail, either
texturally or mineralogically, with the Ampwihi picrite.
A. B. C. D. EK.
SiO, , 46-37 47-25 47-75 42-87 46-0
AleO3 . 10-82 9-07 10-56 10-93 6-8
Fe.03 . 1-60 1-45 0-74 , 3-44 3-0
FeO 5 7-85 10-41 8-34 10-14 7-5
MgO : 20-78 19-96 19-09 16-27 23-9
CaO : 7-94 7-88 9-62 9-11 8-1
Naz O : 0-99 1-38 1-32 0-92 0-8
K.0 j 0-57 0-35 0-12 0-13 0-9
H2,0+ 1:97 0-04 2-06 2-87 \ oo
H,O- . 0-82 0-08 0-05 0-57
CO, f none — — 2-70 n.d.
Ti Og i 0-13 1-61 0-37 tr. n.d.
Pp. Os E none 0-21 0-03 tr. n.d.
MnO : 0-16 0-13 0-10 tr. n.d.
Cr203 0-07 0-13 0-24 n.d. 0-2
NiO : 0-07 0-12 0-07 n.d n.d.
Total - 100-14 100-03 100-46 99-95 99-60
Picrite. Ampwihi Crossing, Mozambique (an. Harwood).
Picritic basalt. Flow of 1840, Nanawale, Puna, Hawaii (an. Steiger).
Diabase? Cathay Hill, Mariposa County, California, U.S.A. (an. Hillebrand).
Hornblende picrite. Ty Croes, Anglesey (an. Phillips).
Peridotite? Loch Garabal, Scotland (an. Player).
HSat>
Returning to the analyses cited above, there are three further
relationships worthy of discussion, namely, the relation of. the
Mg0O/FeO ratio to the percentage of alumina, the association of
potash with magnesia, and that of soda with iron-oxides.
Vogt has shown that in peridotites the ratio of MgO to FeO
increases on an average as the percentage of alumina decreases.
For percentages of alumina between 10 and 11 the atomic ratio of
Mg0O/FeO averages 2°6. In the Ampwihi picrite there is consider-
able divergence from this value, the ratio being 4. Thereisasimilar
divergence in the case of the Cathay Hill Diabase, the ratio of which
is 3°8. The three other rocks cited, however, give ratios that agree
very well with Vogt’s generalization :—
D. 18 BR.
Als Os . c , : : 10-93 9-07 6:8
Atomic ratio MgO/FeO . 2-2 3-0 4-2
1 A. EH. Y. Zealley, Trans. Roy. Soc. S.A., p. 14, 1915.
2 See A. Harker, Natural History of Igneous Rocks, p. 373, 1909.
A. Holmes & H. F. Harwood—Picrite, Mozambique. 155
_ Washington has recently pointed out the general sympathetic
relation between potash and magnesia, and between soda and iron
oxides in igneous rocks.1. The former relation is exemplified with
one exception (C) by the analyses quoted :—
E. A. B. C. D.
MgO . 23-9 20-78 19-96 19-09 16-27
TO ee 0-9 0-57 0-35 (0-12) 0-13
indicating that the Ampwihi picrite is not different from its
analogues in this respect.
The soda-iron relationship does not hold within the narrow limits
of the five analyses A~E. If soda and potash be compared with the
Mg O/Fe O atomic ratio, however, it will be noticed that with one
exception in each case potash increases, while soda decreases, with
the ratio.
Atomic ratio of K. : A. C. B. D.
Mg O/Fe O . 4-2 4-0 3-8 3-0 2-2
KeO . 5 3 0-9 0-57 (0-12) 0-35 0-13
Naz O 0:8 0-99 1-32 1:38 (0-92)
_ It may not appear that there can be any meaning in such results
as these, drawn as they are from rocks without apparent genetic
relations in either time or place. Such rocks may, neverthless, have
genetic relations in virtue of the processes by which they were
formed. By comparing similar igneous rocks, correspondences and
discrepancies of the kind to which attention has been drawn may
come to be used, when their significance is understood, to suggest the
origin and differentiation of the magmas from which the rocks
have crystallized. It is possible that magnesia-rich magmas do not
readily part by crystallization with their potash, and that they may
selectively absorb and accumulate potash from the rocks through
which they pass in approaching the surface. Similarly, in proportion
to their iron content, magmas may not readily part by crystallization
with their soda, and they may selectively absorb and accumulate soda
from the rocks through which they pass on their upward or lateral
journeys. his digression has led us far from the picrite dyke of the
Ampwihi River, to which we must now return to pick up afresh the
lines of thought suggested by analytical results.
The radium content of the rock, only 0°44-% grams per gram, is
very low. Peridotites appear to average more than this amount,
a composite analysis of ten varieties giving 0°51X10-" grams per
gram.” ‘lwo dunites analysed for radium by Professor Strutt,
however, gave 0°33" and 0:34-" grams per gram respectively.’
The slightly higher result for the picrite is probably due to the
presence of felspathic constituents, which are generally far richer
in radium than olivine or enstatite. ‘The result is of more than
numerical interest merely, for it shows that the dyke cannot have
1 Proc. Nat. Acad. Sci., p. 574, 1915.
2 A. Holmes, Science Progress, 1914, No. 33, p. 16.
3 R. J. Strutt, Proc. Roy. Soc., 1906, A. 77, p. 479.
156 to receive, on behalf of my
colleague on the Geological Survey, this testimony of the value that the
Council attaches to his work. You have referred in generous terms to
Mr. Carruthers’s contributions to our knowledge of Scottish geology, and
to his researches in pure paleontology. His application of scientific
methods of investigation to corals has done much to elucidate stages of
evolution in those lowly organisms, and I believe that your recognition of
this branch of his work will be especially gratifying to him. In economic
geology the demands made upon the staff by the exigencies of war were
sudden and imperative, and no one knows better than myself how well
Mr. Carruthers and his colleagues responded to the call, and for the time
resisted the fascinations of abstract science.
Mr. Carruthers, writing amid the distractions of the Western Front, tells
me that it is
«‘almost impossible to give any adequate expression of my gratitude to the
Society for their award of the Medal. . . . As the bulk of my work has
been concerned with economic geology, the honour of this award is shared
equally with my comrades on the Survey. . .. In the field of abstract
science my ventures have been little more than tentative. J hope that the
generous encouragement that they have always received from the Society
may ultimately be repaid in some degree. The obligation is, of course,
greatly increased by this additional proof of trust”.
May I express the hope, for myself and for the Fellows of the Society,
that it will not be long before Mr. Carruthers can resume his scientific work
and justify the confidence that you have so gracefully expressed in his
promise for the future ?
In presenting the Balance of the Proceeds of the Wollaston
Donation Fund to Percy George elena Boswell, D.Sc., the
oe said :-—
r. BosSwELL,—The Balance of the Proceeds of the Wollaston Donation
Fund has been awarded to you by the Council in recognition of your work
in East Anglia, by which you have added to our knowledge of the
subterranean as well as the superficial geology of that area. In your earlier
contributions you examined the origin of the existing river-system of
Suffolk, and also endeavoured to define the limits of extension of the Lower
Glacial deposits of Norfolk into the more southerly county. You have also
made instructive researches into the lithology and mineralogy of many of
the sedimentary deposits of East Anglia. In a paper read before this
Society two years ago you employed this method, in conjunction with
stratigraphical observation, in a comprehensive study of the Lower Hocene
strata of the area, and drew interesting conclusions concerning the
geography of the period and even the tectonics of the country. Your more
recent investigations concerning sands suitable for glass-making have
a direct practical application of much importance at the present time.
Some part of your work has been the outcome of a grant from the Daniel
Pidgeon Fund, and the good use which you made of that opportunity
assures us that you will regard the present award as an incentive to new
enterprises in the service of Geology.
The President then handed the Balance of the Proceeds of the
Murchison Geological Fund, awarded to Dr. William Mackie, to
Dr. W. T. Gordon, for transmission to the recipient, said :-—
Dr. Gorpox,—The Balance of the Proceeds of the Murchison Geological
Fund has been awarded by the Council to Dr.. Mackie in recognition of his
190 Reports & Proceedings—Geological Society of London.
contributions to the geology of Northern Scotland. A skilled chemist as
well as a keen petrologist, he has utilized in this way his leisure as
a medical practitioner during the last twenty years.
By his investigation of the sandstones of Eastern Moray he has thrown
light, both on the source of the material and on the climatic conditions
which prevailed during its deposition. In the cement of these sandstones
he detected traces of the heavy metals, and his inquiry led to the discovery
in quantity of barytes and fluor in the Elgin Trias. His petrographical
work includes an interesting study of the granites of the North of Scotland,
and he has also carried out a large series of chemical analyses of igneous
and sedimentary rocks in order to elucidate theoretical questions suggested
in the course of his researches.
His recent discovery of plant-bearing cherts in the Old Red Sandstone of
Rhynie (Aberdeenshire), has added a new interest to that formation.
Dr. Kidston and Professor Lang recognize these cherts as silicified layers
of peat, and a new class of vascular Cryptogams, the Psilophytales, has
been made for the reception of the plants which they contain.
I ask you, in forwarding this award to Dr. Mackie, to convey to him our
hope that he will thereby be'encouraged to continue the researches which
he has hitherto pursued with such enthusiasm.
The President then presented a moiety of the Balance of the
Proceeds of the Lyell Geological Fund to Arthur Hubert Cox, Ph.D.,
said :—
Dr. Cox,—The Council has awarded to you one moiety of the Proceeds of
the Lyell Fund in recognition of the value of your work among the Lower
Paleozoic rocks. Since you read before this Society, five years ago,
a paper on the Pedwardine Inlier, you have devoted much time to geological
researches in Wales, both South and North. Your paper on the Abereiddy
and Abercastle district was a valuable contribution to the stratigraphy and
tectonics of Pembrokeshire, and gave evidence of skilful and accurate work
in the field. On the petrological side, too, it added to our knowledge of
the Ordovician igneous rocks, a subject to which you have also given
attention elsewhere. Your work in the Cader Idris district, of which we
have as yet only a preliminary account, seems to be of the same thorough
quality ; and, in thus marking our appreciation of what you have already
done, we look forward to results not less important from your geological
labours in the time to come.
In handing the other moiety of the Balance of the Proceeds of the
Lyell Geological Fund, awarded to Tressilian Charles Nicholas, M.A.,
to Mr. H. Woods, for transmission to the recipient, the President
said :—
Mr. Woops,—A moiety of the Proceeds of the Lyell Fund has been
awarded to Mr. T. C. Nicholas as a mark of appreciation of his work on the
older Paleozoic rocks of Carnarvonshire. The results of that work are
represented firstly by a paper on the Geology of the St. Tudwal’s Peninsula,
in Lleyn, read before this Society in 1914. Therein he gave a comprehensive
account of the succession, fossil contents, and classification of the Cambrian
strata of the district, and established the unconformity which exists between
these beds and the overlying Ordovician. This paper was supplemented in
the same year by a paleontological one dealing with the rich trilobitic
fauna, of Middle Cambrian age, which his researches had discovered.
A number of new and interesting species were described, and the succession
of forms was correlated with that recorded for other areas.
As an old friend of Mr. Nicholas, and one who has seen something of the
difficulties presented by the Lleyn district, I am pleased that it falls to my
lot to.extend to him, on behalf of the Council, this token of recognition of
his geological and paleontological work.
Reports & Proceedings—Geological Society of London. 191
The President then presented the Balance of the Proceeds of the
Barlow-Jameson Fund to Mr. Henry Dewey, said :—
Mr. Drwry,—The Proceeds of the Barlow-Jameson Fund have been
awarded to you in recognition of your services to Geology and as an
encouragement to you for the future. In the record of your geological
work the first place belongs to your researches in North Cornwall, where
you were engaged as an officer of the Geological Survey. There your
mapping led you to recognize a number of subdivisions of the Devonian
strata and to determine their natural sequence, and with this help you were:
able to demonstrate the existence of important overthrusts in that area.
The peculiar features of the ‘pillow-lavas’ intercalated in the Upper
Devonian also engaged your attention, and your paper on the ‘spilitic
series’, written in collaboration with Dr. Flett, has proved a valuable:
contribution to petrology. Of not less consequence, of another kind, were:
your paper on the Raised Beach of North Devon and that which you read
before. this. Society a year ago on the Origin of River-gorges in Cornwall
and Devon. Your removal from the West of England to the Thames:
Valley introduced you to new problems, to which you have brought the
same zeal and insight, and it is our hope that you will find in the present.
award an incentive to further investigations in the field of Geology.
The President proceeded to read his Anniversary Address, including
first obituary notices of Jules Gosselet (elected Foreign Member in
1885), J. W. Judd (el. Fellow 1865), J. H. Collins (el. 1869),
C. T. Clough (el. 1875), Clement Reid (el. 1875), Bedford McNeill
(el. 1888), H. Rosales (el. 1877), W. E. Koch (el. 1869), C. Dawson
(el. 1885), T. de Courcy Meade (el. 1891), and others.
The remainder of the Address dealt with some aspects of igneous.
action in Britain, and especially its relation to crustal stress and
displacement. This relation appears not only in the distribution of
igneous activity in time and space, in the succession of episodes, the
habits of intrusions, etc., but also in the petrographical facies of the
igneous rocks themselves. The cause of such relation was sought in
the existence of extensive inter-crustal regions in a partially molten
state: that is, with some interstitial fluid magma, which must
normally be rieh in alkaline silicates. There will be a continual
displacement of the interstitial magma from places of greater stress.
to places of less stress, and certain broad differences in chemical
composition are therefore to be expected between the igneous rocks
of orogenic belts and those erupted in connexion with gentle
subsidence..
The Archean plutonic rocks were intruded in close relation with
powerful lateral thrust, and they accordingly include no alkaline
types; but the Dalradian sediments were deposited in an area of
tranquil subsidence, and the lavas intercalated in them are of the
spilitic kind, rich in sodic felspars.
The Lower Paleozoic formations were laid down in a geosyncline,
which for a long time experienced merely a slow depression, and the
late Cambrian and early Ordovician eruptions, situated chiefly along
the borders of the area, had a pronounced sodic facies. In mid-
Ordovician times there entered a certain element of lateral thrust,
and accordingly in the Llandeilian vulcanicity the spilitic type gave
place to the andesitic; but the scattered outbreaks of Bala and
Silurian age often afford evidence of a reversion to the earlier facies.
192 Reports & Proceedings—Geological Society of London.
Following upon the great Caledonian crust-movements there was,
in the Scottish Highlands and elsewhere, a copious intrusion of
plutonic magmas, all of ‘‘calcic’’ as contrasted with alkaline types.
The same characteristic belongs to the igneous rocks of the Lower
Old Red Sandstone, which were extruded and intruded in connexion
with the later Caledonian folding, while the country was still in
a condition of stress. With the dying out of this stress a more
alkaline facies supervened, and the Lower Carboniferous igneous
rocks of Scotland, though developed largely in the-same synelinal
folds as the preceding series, present a strong contrast in petro-
graphical characters. They indicate a certain richness in soda, and
this feature becomes more pronounced, until it culminates in the
Permian of Ayrshire and East Fife in highly alkaline rock-types.
In Southern England, remote from the main Caledonian dis-
turbance, the Devonian and Carboniferous lavas are of the same
spilitic type as those of the early Ordovician. Later, this part of the
British area was involved in the Hercynian crust-movements, which
were accompanied by the intrusion of the Cornish granites and their
satellites.
In Mesozoic times our country experienced no orogenic disturbance
of a pronounced type, and there was a prolonged cessation of igneous
activity. The Tertiary Era introduced a new factor in the form of
very extensive plateau-faulting, bearing no relation to the structure
of the country. Thismovement, generally of the nature of subsidence,
affected a vast area, of which Northern Britain is only a small
fraction, and was attended by igneous action on the same extensive
scale. The mechanism of extrusion and intrusion differed in im-
portant features from that illustrated by the Paleozoic eruptions.
The Tertiary igneous rocks, as a whole, are decidedly, though not
strikingly, rich in soda; but this alkaline character is lost in the
neighbourhood of isolated centres, where there is evidence of locally.
developed stresses of an acute type.
The ballot for the Officers and Council was taken, and the following were
declared duly elected for the ensuing year :—
_Orricers: President, Alfred Harker, M.A., LL.D., F.R.S. Vece-Presi-
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Professor William Johnson Sollas, M.A., LL.D., Se.D., F.R.S.;. and
Arthur Smith Woodward, LL.D., F.R.S., F.L.8. Secretaries, Herbert
Henry Thomas, M.A., Sc.D. ; and Herbert Lapworth, D.Sc., M. Inst. C. E.
Foreiyn Secretary, Sir Archibald Geikie, O.M., K.C.B., D.C.L., LL.D.,
Se.D., F.B.S. Treasurer, James Vincent Elsden, D.Sc.
OTHER Mermpers oF Councit: Charles William Andrews, D.Sc., F.R.S.;
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Gilbert Cullis, D.Sc. ; Arthur Morley Davies, D.Sc., A.R.C.Se. ; Professor
Edmund Johnston Garwood, M.A., Se.D., F.R.S. ; Walcot Gibson, D.Se. ;
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Robert Heron Rastall, M.A.; Professor Thomas Franklin Sibly, D.Se. ;
Sir Jethro J. Harris Teall, M.A.. D.Se., LL.D., F.R.S.; and Samuel
Hazzledine Warren.
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; I. ORIGINAL ARTICLES. —Page REVIEWS (continued). Page
Eminent Living Geologists: Pro- —Areas of the Atlantic Slope—
fessor Henry Fairfield Osborn, Cretaceous Crabs, Dakota—Flora
LL.D. (With Portrait, Pl. XII.) 193 of the Fox Hills Sandstone—
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The Base in the Camerate III. REPORTS AND PROCEEDINGS.
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Reactions on Copper Sulphides— Harry Page Woodward,J.P.,F.G.S.,
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Fossil Fishes in U.S. National VI. MISCELLANEOUS.
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No. V.— MAY, 1917. \ fe
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ORIGINAL ARTICLES. \
—o——_. ~
I.—Eminent Livine Geonoaists.
Henry Farrrrerp Ossory, LL.D. (Princeton, Columbia, Hartford),
Sc.D. (Cambridge, Princeton), Ph.D. (Christiania), AB. (Prince-
ton); Foreign Member of the Linnean and Geological Societies
of London; President of the American Museum of Natural
History, New York.
(WITH PORTRAIT, PLATE XII.)
pet nearly half a century geologists have followed with great
interest and admiration the discoveries of fossil vertebrate
animals in the west of North America. From the early days when
western pioneers brought back scattered fragments for study by
Leidy, to the seventies and eighties of last century when Cope and
Marsh led or encouraged adventurous expeditions to collect fossils
in the territories then occupied by hostile Indians, the continual
succession of new forms of extinct reptiles, birds, and mammals met
within an unusual state of preservation, excited increasing attention.
So remarkable, indeed, were these finds and so sporting was their
pursuit, that rivalries arose and passed beyond the state of friendly
emulation which is good for real progress. It was thus fortunate
for American paleontology that a younger generation of well-trained ©
enthusiastic students was then ready to enter the field, and especially
. fortunate that their leaders were imbued with a harmonious spirit of
co-operation. Among these leaders was the subject of our present
biographical sketch, who has perhaps done most by his personal
influence to maintain the happy relations which now exist between
all workers in vertebrate paleontology in America.
Henry Fairfield Osborn was born on August 8, 1857, at
Fairfield, Connecticut, and began his education at the Lyons
Collegiate Institute, New York. He next proceeded to Princeton
University, where he graduated as A.B. in 1877. In 1879-80 he
followed post-graduate studies under F. M. Balfour at Cambridge,
and under Huxley at the Royal College of Science, London. In
1881 he became Assistant Professor of Natural Science at Princeton,
and from 1883 to 1890 he was Professor of Comparative Anatomy in
the same University. In 1891 he removed to New York, where he
had been appointed Da Costa Professor of Biology in Columbia
University and Curator of Vertebrate Paleontology in the American
Museum of Natural History. In 1896 his Professorship was restricted
to Zoology alone, and in 1910 he resigned both this and his Curator-
ship, being nominated Research Professor of Zoology in Columbia
DECADE VI.—VOL. IV.—NO. V. 13
a6
a>
194 Eminent Living Geologists—
University. In 1901 he was elected a Trustee of the American
Museum of Natural History, and was second Vice-President from
1901 to 1908, when he assumed his present office of President of the
Board of Trustees. In 1900 he succeeded Professor O. C. Marsh as
Vertebrate Paleontologist to U.S. Geological Survey, and from 1900
to 1904 he was Vertebrate Palzeontologist to the Geological Survey of
Canada in succession to Professor E. D. Cope. In 1906 he was
offered but declined the Secretaryship of the Smithsonian Institution,
Washington.
Professor Osborn was specially trained as a zoologist, and several ©
of his earlier papers relate to the structure and development of the
brain. In association with his fellow-student, William Berryman
Scott, however, his interest was soon aroused in extinct animals by
the discoveries of Cope and Marsh; and in 1877 he began his life-
work in paleontology by joining Scott and Francis Speir, jun., in an
expedition to collect mammalian remains from the early Tertiary
formations of Wyoming. On his second collecting trip in 1879,
in the Washakie Eocene Basin of Wyoming, he recognized the
possibility and importance of making more exact stratigraphical
records than had previously been attempted; and from that time
onwards he, with his pupils and associates, has paid so much attention
to the stratigraphy of the deposits yielding vertebrate fossils, that
the order of succession in each region explored is no longer a matter
of inference and speculation but a definitely ascertained fact. It has
thus become possible to use successive groups of vertebrate fossils
with confidence when tracing changes in their peculiar characters
through geological time; and many phenomena have become clear
which would otherwise have been overlooked.
The precise determination of the relative ages of the extinct
mammals in North America naturally suggested a reconsideration of
the mammal-bearing Tertiary deposits in the Old World, and between
1898 and 1900 Professor Osborn obtained the help of several European
paleontologists in preparing a table of ‘‘ Correlation between Tertiary
Mammal Horizons of Europe and America”’. As discoveries pro-
eressed he continued to improve this correlation, and it was extended
and brought so far as possible up-to-date in his handsome volume,
The Age of Mammals in Europe, Asia, and North America, published
in 1910. In connexion with these researches it is interesting to note
that in 1900 Professor Osborn reached the conclusion that the common
ancestors of the Proboscidea, Sirenia, and Hyracoidea would be found |
in Africa—a conclusion that was immediately afterwards confirmed
by the discoveries of Dr. C. W. Andrews and Mr. H. J. L. Beadnell
in the Egyptian Fayum.
In his long series of descriptive papers and memoirs Professor
Osborn has dealt with almost all groups of mammals and reptiles,
but special reference may be made to his important contributions to
our knowledge of the Rhinoceroses, Horses, Titanotheres, and
Dinosaurs. For the last fifteen years he has been occupied with
a Monograph of the Titanotheres, which will shortly be. published
by the United States Geological Survey. For ten years he has also
been accumulating notes for a similar Monograph of the Sauropodous
a
§
,
:
fi
.
.
Henry Fairfield Osborn. _ 195
Dinosaurs. His most recent memoirs include those on the gigantic
earniyorous Dinosaur Tyrannosaurus and on the integument of the
Tguanodont Dinosaur Zrachodon, both astonishing discoveries.
While engaged in descriptive work, Professor Osborn has always
been keenly appreciative of its philosophical bearings, and he has
published many dissertations on the transmission of acquired
characters, mutations, adaptive variations, and allied subjects. In
1894 he contributed to the Columbia University Biological Series
an important volume entitled From the Greeks to Darwin, which has
been several times reprinted, and has also been translated into
Italian. He discussed ‘‘ Darwin and Paleontology”? in the volume
on Fifty Years of Darwinism, published by the Cambridge University
Press in 1909. He stated the biological conclusions drawn from his
study of the Titanotheres in a paper read before the National
Academy of Sciences in 1911; and more recently he addressed the
Paleontological Society of America on the ‘‘Origin of Single
Characters as observed in Fossil and Living Animals and Plants”.
Finally, Professor Osborn has made many valuable contributions
to popular scientific literature, and among the latest may be mentioned
his profusely and beautifully illustrated volume on the Men of the
Old Stone Age, their Environment, Life, and Art, which was
published at the end of 1915.
During the greater part of his career Professor Osborn has been
much occupied with administration in varied ways. From 1892 to
1895 he was Dean of the Faculty of Pure Science in Columbia
University. Since 1881 his organization, in connection with the
American Museum, of a complete survey of the geological succession
of the higher vertebrates in North America, has produced a flourishing
school of vertebrate paleontology, represented by Karle, Matthew,
Granger, Gidley, Loomis, Brown, Lull, Peterson, Gregory, and others.
In 1896 he took a very active part in the foundation of the New
York Zoological Park, under the auspices of the New York Zoological
’ Society, of which he has been President since 1909. He is also
a leading member of the New York Academy of Sciences, over which
he presided in 1898-1900; and he has been a Trustee of the New
York Public Library since 1912. Among other offices, he has held
the Presidency of the American Morphological Society (1897), the
Marine Biological Association (1898-1900), the Audubon Society
(since 1910), andthe American Bison Society (since 1914). Finally,
in 1914, he became a member of the Belgian Relief Committee.
Professor Osborn has naturally received many honours both at
home and abroad. He has been admitted to several university
degrees already enumerated, and in 1914 he was awarded the
Hayden Gold Medal by the Philadelphia Academy of Natural
Sciences. He is a Foreign Member of the Linnean and Geological
Societies of London, the Cambridge Philosophical Society, the
Manchester Literary and Philosophical Society, and the British
Association. From frequent visits, indeed, he is almost as well
known to the scientific men of this country as to those of America,
and his personal charm has won for him a large circle of devoted
friends. Those who have visited him in his beautiful home amid the
196 Herbert L. Hawkins—Studies on the Echinoidea, ete.
wooded heights at Garrisons-on-Hudson, have learned to appreciate
the reasons for his success as a leader of men. He is a most
unassuming student in the happiest circumstances, ever eager for the
promotion of natural knowledge, and watchful to make the best use
of all opportunities. To our tribute of admiration we would only
add our best wishes for his continued enjoyment of health and
strength long to carry on the work for which geological science is
already so much indebted to him.
Aas. We
IT.—Morpwotocreat Srupres on tHE Ecutnorpea Hotecrypoipa aNnD
THEIR ALLIES.
By HERBERT L. HAwkins, M.Sc., F.G.S., Lecturer in Geology, University
College, Reading.
(PLATE XIII.)
II. Tue Sconxren Touserctes or Discorpzes anv Conutus.
1. Iyrropucrion.
[* 1914 I published, in this Magazine, an account of ‘‘ Some
Problematical Structures in the Holectypoida”’, indicating
therein the presence of certain sunken features on the test-surface
of ‘* Pygaster”’ (Plesiechinus), Coenholectypus, and Discordes. Two
series of depressions were described, of which one was wholly
sutural in position, while the other was situated on the adoral
ambulacral plates, and consisted of more or less sunken tubercles
or granules. It is with the latter series of structures that the
present paper deals. Although the title ‘‘ problematical structures ”’
remains appropriate, further work and more refined methods of
preparation have made possible a more accurate description of them,
and have considerably increased the area of their known distribution.
Save for comparisons and passing references, the development of
depressions on the tests of the Pygasteride and Holectypine will not
be considered here. In Jurassic times, when these two groups were
at their prime (in this country at least), sunken tubercles were in
an incipient stage of evolution, and are in consequence very difficult —
to distinguish from their normal associates. It is therefore safer to
deal first with the well-matured structures, as developed in Upper
Cretaceous times. Moreover, the condition of preservation, and
especially the character of the matrix, of Chalk fossils, make it
easier to clean and stain the specimens without much. risk of
damage to delicate surface features. A test that has been naturally
exposed by weathering is rarely serviceable for study of these
structures, and more or less elaborate methods of staining and
sectioning are necessary to render them sufficiently clear for accurate
description. Small and inconspicuous as the depressions are, they
nevertheless appear to have considerable phylogenetic and taxonomic
importance. For their physiological value I have no suggestions to
offer. .
2. Tar Ornament oF Discorpzes cyLtinpRicus (LamM.).
(a) Zhe Interambulacra of the Adapical Surface.
An examination of an interambulacral plate midway between the
apical system and the ambitus shows that the somewhat sparse and
Herbert L. Hawkins—Studies on the Echinoidea, ete. 197
inconspicuous ornament consists of no less than five different types
(see Pl. XIII, Figs. 1 and 2),
The primary tubercles are set in shallow areole, and are arranged
serially in a definite pattern (see Hawkins, Grou. Mae., 1911, p. 448).
They are few in number and cover but a small proportion of the
surface of the plate. The secondary tubercles are very small, but
are fairly numerous. ‘They are areolate, but some of them seem not
to possess mamelons. At times they form rough rings around the
primary areole, and occasionally take on an irregularly linear
arrangement in a transverse or radiating direction. The greater
number of them seem to be quite fortuitous in position, and they
vary considerably in diameter. Still more irregular, both in
distribution and size, are the miliary granules, which are present
in about the same numbers as the secondaries.
In addition to these three normal types of ornament, destined for
the support of primary and secondary radioles and pedicellarie, are
two more of quite different appearance. One of these series of
‘“‘tubercles’’ superficially resembles that of the secondary tubercles.
The structures are of about the same size, but differ in the
_ comparative scarcity of the special series, and in the character of
their areole. ‘They are either flush with the surface of the test
(though readily visible owing to their extreme smoothness), or more
commonly, slightly raised above the surrounding level. In the
centres of these smooth circular areas are placed minute and in-
conspicuous mamelons, which seem to be always imperforate. The
mamelons rise from pits of very little greater diameter than them-
selves, and do not project above the level of their ‘‘areole” (see
Tells DUD aa tice ity
The other aberrant series consists of tubercles which may be of
any size from that of a secondary to almost that of a primary,
haying small mamelons on bosses set in areolte which are deeply,
but not entirely, sunk below the plate surface. When a test has
been stained with a granular substance, this type of ornament
becomes very obvious through the accumulation of colouring matter
in the hollows. Although many of the sunken tubercles are situated
without apparent order, some few seem to be fairly constant in
position on the serial plates of a column.
The former series of peculiar ‘‘tubercles’’? will be more fully
described in the section of the paper dealing with Conulus, in which
genus similar structures are much more strongly developed, but
the latter series (apparently absent from Conulus) requires more
precise analysis.
Hxcept that the mamelons of the ‘‘sunken tubercles’’ seem to be
usually, if not always, imperforate, the chief difference between
these structures and the normal primary tubercles lies in the
character of their areole. There seems always to be some sort of
a boss on which the mamelons are placed, though there is hardly any
indication of its base. The floor of the areola is inclined, to make
an angle with the plane of the test-surface, and the inclination is
always adoral and inwards. In most cases the adapical border of
the areola is sensibly raised above the surrounding level. ‘hus the
198 Herbert L. Hawkins—Studies on the Echinoidea, yee
axis of the tubercle (which is at right angles to the surface of the
test in normal cases) slopes away from the apex downwards towards
the ambitus (see Pl. XIII, Fig. 3). There seems to be almost perfect
homogeneity among the sunken tubercles, apart from their variation
in size.
On each of the first few plates from the apical system there is
only one ‘‘sunken tubercle’? (Fig. 1), constantly situated near the -
adoral transverse suture of the plate, and nearer to the interradial
suture than the tubercle of the central (Cidaroid) series. This
particular row of-‘‘sunken tubercles’’ can be distinguished, with
but little variation in relative position, on all the interambulacral
plates of the adapical surface except those immediately above the
ambitus. Its members are commonly larger than the other less
neon any, disposed tubercles of the same type. The number of
‘“‘sunken tubercles” on each plate shows a steady increase until just
above the ambitus, but the depth of their areole shows a corresponding
decrease. They never become very numerous. Although none of
the additional “sunken tubercles” show any constancy “of position
comparable with that of the first-mentioned series, it is a general
rule that the largest and most deeply excavate ones are situated
near to, and sometimes in contact with, the adoral transverse margins
of the plates.
A comparison of Figs. 1, 2, and 4 (Pl. XIII) discloses an interesting
evolutional feature in connexion with the “sunken tubercles”. In
HHolectypus depressus (the Cornbrash form, not that from the Inferior
Oolite) there is,one such tubercle on each of the interambulacral
plates just above the ambitus, but never more than one. The plates
near the apex are without any. ‘This solitary ‘‘sunken tubercle”’
is in precisely the same relation to the central primary as it is in the
adapical plates of D. cylindricus. Thus the ‘‘young”’’ plates of the
Cretaceous Discoides show the same development, in this respect, as
the ‘‘ adult ’’ plates of the Jurassic Holectypus. The evidence for the
phyletic continuity between the Holectypine and Discoidiine thus
receives a convincing addition.
(b) Zhe Ambulacra of the Adapical Surface.
The ornament of the ambulacral plates is on a smaller scale, and
less thickly spread, than that of the interambulacrals, but it consists,
none the less, of a corresponding series of five different structures.
The primary tubercles are, on the whole, very regularly arranged in
vertical series on every third plate. The secondary tubercles are
few, and are usually associated with either a primary areola or
a peripodium. The miliaries are very small, but are relatively
numerous, and for the most part form transverse lines across the
middle of each plate.
The two peculiar types of ornament are both pr esent, the ‘‘ raised
secondaries’’ in fair numbers, and the ‘‘ sunken tubercles” with
much the same frequency for a given area as those of the inter-
ambulacra. I have never seen more than one ‘sunken tubercle”
on an ambulacral plate. As in the interambulacra, there is one
vertical series of these tubercles (situated near the peripodia) which
Herbert, L. Hawkins—Studies on the Echinoidea, etc. 199
tends to occur regularly on every third plate. As the figures show
(Pl. XIII, Figs. 1 and 2), the regularity is not perfect, but in a whole
column the series of tubercles has an average number one-third that
of the plates. There are very few ‘“‘sunken tubercles” apart from
this series. All are identical in structure with those of the inter-
ambulacra.
(c) Zhe Interambulacra of the Adoral Surface.
On the adoral surface, and at the ambitus, the ornament of the
interambulacra suddenly becomes coarser and more abundant. The
primary tubercles increase in size, numbers, and prominence, and
especially in the excavation of their areole. Although their
arrangement is on the same plan as that of the tubercles of the
adapical surface, a series of secondaries becomes enlarged to form an
additional transverse row towards the adapical margin of each
ambital plate. This new series never reaches the size of the true
primaries, but reproduces all the morphological features of that series
on a slightly smaller scale. The normal secondaries are numerous,
very uneven in size, and form very regular scrobicular circles around
the primary areole, though many scattered ones also occur. The
miliaries are few, so that much of the surface of the plates towards |
the peristome is quite smooth.
The ‘‘raised secondaries ’’ maintain their numbers over the whole
surface, but are proportionately smaller than those of the adapical
region. Their ‘‘areole’’ seem to be more noticeably elevated above
the average plate level, but their mamelons are still minute and
lacking in prominence. [I have failed to find any ‘‘ sunken tubercles”’
below the ambitus on the interambulacra, and, in view of the
remarkable freedom from ornament of the plates near the peristome,
I feel fairly confident in stating that they do not occur there.
(d) The Ambulacra of the Adoral Surface.
The most striking difference between the ambulacra and inter-
ambulacra of the adoral surface, in the matter of ornament, lies in
the development of unusually numerous secondary tubercles and
. miliaries in the former areas. Both of these sets of structures are
far from numerous on the adapical parts of the ambulacra, so that
the adoral parts of these areas are distinguished from all the rest of
the test-surface by their abundantly granular character. In scale
this ornament is perhaps a little finer than that of the adjoining
interambulacra.
The ‘‘raised secondaries’’ are present, though far from abundant, —
and are precisely similar to those on the adoral interambulacral
plates. But, in contrast with the latter areas, ‘‘ sunken tubercles”’
occur in addition. They are, however, very small, and seem to
belong exclusively to the regular series of the adapical surface.
They are restricted to the immediate neighbourhood of the “ pori-
ferous zones’’, and are placed with fair regularity on the perradiad
side of every third peripodium. ‘The plates on which they occur are,
in the majority of cases, demi-plates. I have been unable to locate
them with certainty on the plates at the ambitus, but these are so
200 Herbert L. Hawkins—Studies on the Echinoidea, ete.
small and so congested with granular ornament that their absence
from that region is probably more apparent thanreal. Their general
proportions and distribution are accurately shown in Pl, I, Fie. 3 :
of Got. Mac., Dee. VI, Vol. I, 1914. It is noteworthy that the
obliquity of their axes is exactly opposite to that of the adapical
tubercles, the areole being inclined towards the ambitus in each ease.
(e) Zhe Homology of the ‘‘ Sunken Tubercles” of Discoides and the
‘* Glassy Tubercles”’ of Echinoneus.
The ‘sunken tubercles” of D. cylindricus are found over the
whole coronal surface of the test except near the apex and on the
interambulaera of the adoral surface. Their distribution on the plates
seems to indicate that they are not fundamentally special structures
but are modified examples of the secondary tubercles. As far as
can be ascertained, the areole of the ‘‘sunken tubercles” are
geierally raised above the surrounding level on the side away from
the ambitus, and are sunk more or less deeply below it on the
opposite side. The greater part of each areola is depressed, and the
sunken part is deeper than the raised part is high. Thus their
mamelons, and whatever articulated projections that may have fitted
on to them, are inclined towards the ambitus. ‘These structures
occur in Plesiechinus, Pygaster, Holectypus, and Coenholectypus as
well as in Discordes, but, as far as my present observations have
indicated, reach their maximum development, at least as regards
numbers, in the last-named genus. They seem not to occur in
Conulus. The material at present available for a study of Pyrina is
inadequate, but I believe that they do occur in P. desmoulinst,
though in that species they seem to be wholly sunken, with an axis
once more at right angles to the surface of the test. I have not seen
any comparable structures in any other Mesozoic genera.
There are two sets of structures found in Tertiary and Recent
forms with which comparison is possible. Many of the more
specialized Spatangoids, such as Zoventa and Hupatagus, have a few
large tubercles on the interambulacra of the adapical surface. These
are set in very deeply sunken areole, and are usually oblique in
relation to the test-surface. But two equally important features in
the Spatangoid tubercles are in direct contrast with those of Diseordes
and its allies. The sunken tubercles of the recent forms are always
primaries, in point of size, while those of Discoides are always
smaller than the main tubercles; and the sunken character of the
Spatangid areole seems to be due to the development of secondary
thickening on the rest of the plates, and its absence from them, while
the actual elevation of part of the areole in Discordes shows that
such a growth has played no part in their production.
The other series of sunken tubercles with which comparison can
be made is found in EHehinoneus and Micropetalon. There can be
little doubt that, from a phylogenetic standpoint, these genera are
much more nearly related to the Holectypoida than are the true
Spatangids, although it seems equally certain that they are not
directly descended from Discotdes. Scattered more or less pro-
miscuously over the plates of both areas in Hehinoneus are the small
0 a ee a
st ae
Herbert L. Hawkins—Studies on the Echinoidea, ete. 201
depressed structures known as ‘‘glassy tubercles”. Their structure
and distribution are admirably figured by Westergren (Mem. Mus.
Comp. Zool., Harvard, 1911). These glassy tubercles are roughly
similar to the secondaries in size, but are distinguished from them
by their deeply sunken areole and small ‘‘mamelons”. Whatever
the glassy tubercles may be, either in origin or function, their
general facies is so extraordinarily like that of the ‘‘ sunken tubercles”’
of Discoides that it is almost impossible to doubt the homology of the
two structures. I have not noticed any specially vitreous appear-
ance in the mamelons of the ‘‘sunken tubercles’’ of Discoides, but
this might be due to fossilization or the imperfect development of the -
structures in Cretaceous times. If, as I believe, corresponding
structures occur in Pyrina, which is very nearly allied to Hehinoneus
in all essential features, and almost certainly ancestral to it, the
correlation of the two sets of ornament would be rendered more
certain. Their absence from Conulus would indicate that that genus,
though resembling Pyrina in many features, has diverged along
a line of evolution leading to some other goal than Echinoneus, and
one in which “ glassy”’ or ‘‘sunken” tubercles are not developed.
For the present it is enough to definitely state the opinion that the
“(sunken tubercles” of most Holectypoids are the forerunners of
the glassy tubercles of Hehinoneus.
3. Tae Sernirenous Pirs or ConuLus ALBOGALERUS, LESKE.
(a) Description of the Pits.
This familiar and common species from the higher zones of the
Upper Chalk may present very different surface features under
varying conditions of preservation and preparation. Ordinarily the
surface of the test is almost smooth on the adapical surface, owing to
the faint relief and shallow areole of the primary tubercles, and the
small size of the secondaries and miliaries. But most specimens
that have been freed from their adherent matrix by gentle methods
show, in contrast, a strongly shagreened character, which is caused
by the projection of very numerous rounded prominences of con-
siderable elevation but small diameter. These prominences are
readily detached from the plates by too vigorous brushing, and seem
to separate from them after a very slight degree of weathering; and
they as often as not are removed with the matrix if this is broken off
by a blow. That they commonly remain in position on tests
which have been entirely denuded of radioles and pedicellarie
indicates that these prominences are not appendages of that type, but
their frequent and easy separation from the plates with which they
articulate proves that they are not tubercles. They seem to occur
in almost the same numbers in C. rhotomagensis and C. subrotundus
as in C. albogalerus, but owing to the toughness of the matrix in
which the two former species are embedded, they are only
exceptionally seen in situ.
The earliest description of the prominences scattered over the test
of C. albogalerus is that given by Forbes (Mem. Geol. Surv., dec. 111,
pl. viii) in 1850, and no later accounts of them seem to add much to
his statements and figures. ‘The following are the sections of his
3
202 Herbert L. Hawkins—Studies on the Echinoidea, ete.
discussion of ‘‘ Galerites”’ albogalerus which bear upon the subject.
“ Tbid., 1912, p. 203.
6 “Botanical Evidence against Recent Glaciation of New Zealand’’: |
Trans. N.Z. Inst., vol. xlii, pp. 348-53, 1909.
DECADE VI.—VOL. IV.—NO. VI. 16
24.2 C. T. Trechmann—Glacial Controversy
seems to carry great conviction, though I am not competent to offer
any useful opinion on this matter.
Other New Zealand geologists appear to adopt an attitude of
neutrality, or so far as they have expressed any opinion on the
subject seem to lean towards the view that the glaciation was of
a localized and not of a regional character.
The glacial or reputed glacial sections and boulders I have actually
seen in New Zealand are comparatively few, but in so far as they
affect the questions above-mentioned they are important and critical
ones. The evidence of a general nature dealing with the two
contending views has been so thoroughly put forward in the papers
quoted that to go into it would merely be repeating what has already
been written, so I shall confine myself to giving my own interpreta-
tion of the sections I visited.
Taking the question of the North Island first, Professor Park says
in his Geology of New Zealand,! where he devotes many pages to a
detailed description of the various sections, ‘‘In the Rangitikei
watershed there is a glacial moraine of great extent composed of
andesitic blocks torn from the higher slopes of the voleano Ruapehu
and transported across the Rangitikei divide into the lower Hautapu
valley. ‘I'his conspicuous moraine sheet is spread over the denuded ~
surface of marine clays of Pliocene age.’”? He speaks of this as the
Hautapu or older glacial drift and the Hautapu till.? :
When I was in New Zealand in 1915 I heard that Professor Park
had found one of these andesite boulders bearing strie which placed
its glacial origin beyond question. I mentioned this matter to him
when I had the pleasure of meeting him, and he kindly gave me
instructions as to where I could see the boulder. Professor Park has
recently described this boulder in detail,* and gives an excellent
photograph both of the whole mass and a nearer view showing the
scratches on it.
This boulder bearing the scratches is of prime importance because:
it seems to me that the question of the glaciation of the North Island
practically stands or falls with this boulder. 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 in the North Island fails.
I came away convinced that the scratches on the boulder are not
glacial, and that they could have been and were caused by other
means. I do not desire in any way to appear to take sides in this
controversy, but with due respect to Professor Park’s opinion I must
say that I differ from him as regards the mode of origin of the
striations on this boulder.
It is situated on the slope of a hill on the south side of the entrance
of a railway tunnel south of Mangaweka station, several hundred
feet above the deeply cut gorge of the Rangitikei River, and
about 85 miles south-south-east of the summit of Ruapehu. It
measures about 14 x 8 x 6 feet, and must weigh about 35 tons.
' Geology of New Zealand, 1910, p. 183.
2 Thid., 1910, p. 205.
3 Trans. N.Z. Inst., vol. xlviii (N.S.), pp. 185-7, 1915.
im New Zealand. 243
Professor Park says the whole of the under side of the boulder is
scratched, but when I was there the vegetation round about it
was very thick, but that portion of the under surface which I saw
is clearly scratched. ‘The surface of the boulder is much decomposed
and weathered, and the little crystals composing the andesite can be
rubbed off with the finger-nail, and in fact the surface can almost
be seratched with the finger-nail, and scratches can easily be made
on it with a knife blade.
The boulder rests on a slope and has evidently moved down from
higher ground and must move further down in the future towards
the river. ‘The scratches could, in my belief, easily have been made
by the movement of the boulder over gravelly soil or over other
stones. Glacial scratches could not have survived the weathering to
which the surface of this boulder has evidently been subjected.
It is true that on the summit of Ruapehu at the present day there
exists a small glacier or ice-field at an altitude of from 7,000 to
9,000 feet, but there is nothing to show that it was ever more
extensive or that Ruapehu had attained its present altitude in the
Pleistocene period. Professor Marshall has pointed out that the slopes
of the volcano show no evidence of former glaciation.
The question certainly arises as to how these large andesite
boulders come to be scattered over the countryside in such numbers
. west and south-east of the parent voleano down the Hautapu Valley.
Until the district has been accurately surveyed and their distribution
mapped it is difficult to say what was the actual mode or direction of
transport. They seem to be relics of former gravel or boulder beds
which have survived and in some cases become isolated owing to their
large size, but exactly at what period the beds were deposited cannot
be asserted at present. :
I may point out here that it rests with the upholders of a glacial
origin for any beds to show that the phenomena cannot have
originated in any other way than by glacial action. If their opponents
cannot exactly explain the mode of origin of certain deposits it does
not necessarily follow that the beds are glacial.
The deep and immature rock valleys seen in the southern part of
the North Island, and especially round and near Wellington, are the
very converse to what one would expect to find on the ice-sheet
hypothesis. Under ice-sheet conditions they would have immediately
been filled up with glacial debris.
Turning now to the South Island, the evidence that there was
anything in the nature of an ice-sheet rests primarily on some deposits
near the east coast of Otago. The largest of these is called the
Taieri or Henley moraine. Professor Park describes it as the largest
and most important: pile of glacial drift in New Zealand. It forms
the range of hills bounding the eastern side of the Taieri Plain, and
rests against a ridge of mica-schist which separates that plain from
the sea and rises to a height of 1,000 feet above sea-level. It extends
from Allanton, 15 miles south of Dunedin, to a point in the Clutha
Valley, a distance of about 25 miles: Material very similar to that
which composes the Taieri ‘‘ moraine”’ also forms the celebrated Blue
Spur near Lawrence, which Professor Park also describes as glacial
244 ©. T. Trechmann—Glacial Controversy, New Zealand. fai
drift and which has long been worked for gold, and there are other
outliers of a similar schistose conglomerate. In the Taieri Hills the
more or less bedded material dips west at various angles. Professor
Park states that the dip is towards the north-north-west for a distance
of 2 miles at angles of 10 to 33 degrees. Its thickness is also very
considerable, reaching apparently 1,500 feet. In addition to being
tilted and faulted it has suffered prolonged erosion, and the deep
valley of the Taieri River has been cut right through it.
The Dunedin—Invercargill railway skirts the western side of this
chain of hills for over 20 miles, and it forms a very conspicuous
feature of the topography.
If these hills were glacial—and when plotted on a map the outline
of this rock certainly suggests in shape a great terminal moraine
stretching parallel to the coast for many miles—then there must
indeed have been a vast ice-sheet debouching from the Alpine region
towards the east coast.
I am, however, convinced that they are not glacial. I visited the
locality in company with Professor Marshall with a view to seeing
this line of hills and of examining the sections exposed near Henley
and in the gorge of the Taieri River which cuts through the supposed
moraine. The material is almost, if not entirely, composed of schist ;
in places it is clearly current-bedded and sometimes very hard and
compact. Masses of a very big size do not seem to occur. Professor
Park says that pieces over 12 feet are exceptional, but the largest
I saw were much smaller than that. He also adds that no striated
boulders occur in it, and certainly I saw none.
I was struck with the dissimilarity of this deposit to any glacial
moraine I had eyer seen. Both this and the gold-bearing deposit of
Blue Spur near Lawrence in Otago are deposits of post-Jurassic age
and rest unconformably on the underlying mica-schist, but whether
they are associated with the late Cretaceous or with the Tertiary
periods of deposition must await further investigation.
New Zealand geologists should be able to trace these schistose
conglomerates in some definite association with undoubted Cretaceous
or Tertiary deposits which should settle the question. Sir James
Hector and A. McKay associated the Taieri deposits with the
brown-coal series of supposed early Tertiary age.
There is evidence that the Henley or Taieri conglomerate mass is
faulted parallel to the Taieri basin, but the fault is nowhere seen.
The material at Blue Spur is certainly faulted, and the faults are
clearly revealed by the gold-sluicing operations. There are certainly
recent fault dislocations in New Zealand, but those at Blue Spur
appear to be of much earlier date than Pleistocene.
The removal of these schistose faulted conglomerates of Hastern
Otago from the domain of glacial action removes also the chief
evidence for any pre-Pleistocene glaciation. The traces of the Alpine
glaciation are so fresh that any question of their being of Pliocene
age is excluded.
Finally, as against the ice-sheet theory it may be mentioned that
the two masses of Tertiary volcanic rocks of the Otago and Banks
Peninsula on the east coast occupy a similar position relatively to
R. M. Brydone—Chalk Zone of Holaster planus. 245
the Alpine chain as the Cleveland Hills do to the centres of ice
distribution in England or the Jura to the Swiss Alps. Had there
ever been an ice-sheet in the South Island it must have extended
at least to the foot of these elevated masses. Yet no trace of
transported erratics is seen on the slopes of these hills nor on the
plains between them and the Alpine range, nor have any glacial
striee been recorded on them.
Turning now to the Pleistocene glacial phenomena we find these
splendidly developed along almost the whole length of the Alpine
system of the South Island. The only place where I have had the
opportunity of examining them at all closely is in the district of
Lake Whakatipu. Here are all the features of a glaciation of the
Alpine type splendidly displayed. There is the deep lake basin of
Whakatipu, and how far this is due to the action of the ice affords
the same opportunity for discussion as do the Swiss lakes. A fine
are-like terminal moraine spans the end of the lake at Kingston,
having a length of 19 miles, and is cut through by the stream that
drains the lake. At Bob’s Cove, half-way up the lake, a fine series
of erratics and striated surfaces is seen.
I came to the conclusion that there is no evidence of Pleistocene
glaciation in the North Island, and that in the South Island the
glaciation was of an Alpine and not of a regional type. The Pliocene
and Pleistocene marine molluscan faunas show no evidence of the cold-
water conditions such as occurs in countries that have experienced
the conditions attendant upon the advance and retreat of an ice-sheet.
It remains for New Zealand geologists to determine whether there
is in their Alps a succession of glacial deposits separated by inter-
glacial episodes, or, as seems much more probable, that there was one
glacial period whose deposits exhibit all the freshness shown by the
remains of the Wiirm glaciation of the Kuropean Alps. Such seems
to be the case with the glacial deposits I saw at Lake Whakatipu.
Il.—TuHe Base or tap CHatk Zong or HoLASTER PLANUS IN THE
Iste oF WicuHt.
By R. M. BRYDONE, F.G.S.
STARTING with the bed labelled “‘ Bieavea bed’’ by Rowe,’ the
following generalized section represents the downward sequence
in the Isle of Wight.
1. Bicavea bed. Feet.
Seam of grey marl (‘‘ Grey Marl’’).
2. Hard rough nodular chalk . j P ; 3 : ; % 8-10
Seam of dark marl (‘‘ Black Marl ’’).
3. Very hard lumpy chalk, containing a layer of green-coated nodules
and passing in its lower 2 feet or so into smooth white chalk
veined with marl . : ; 4 ‘ , ; : Se le alta
Seam of marl.
4. Firm smooth white chalk in massive courses separated by seams
of marl.
' The Zones of the White Chalk of the English Coast, pt. v, p. 220.
246 R&. M. Brydone—Chalk Zone of Holaster planus.
The ‘‘ Bicavea bed” is universally accepted as part of the zone of
Holaster planus. The smooth white chalk in massive courses is the
typical chalk of the zone of Terebratulina lata. Where between
them is the boundary between the two zones to be drawn?
[It will be convenient to have short names for the two beds
numbered 2 and 3 above. Membranipora Vectensis, Bryd., is a
striking form very characteristic of Bed 2, and it will be called the
‘“‘Vectensis bed”’. Bed 38 is described in all published sections as
containing a layer of green-coated nodules, and I have therefore used
these words; but inthe Compton Bay section by far the most prominent
layer is a continuous greenish-yellow stony layer, forming a sort
of culminating point to the progressive hardening which has been
going on both from above and below. The ‘‘layer of green-coated
nodules’ has been named by Rowe the ‘‘ spurious Chalk Rock”, and
the bed will be called the ‘‘spurious Chalk Rock bed”. |
For a long time before 1903 the ‘“‘spurious Chalk Rock”, or
perhaps more accurately the ‘‘spurious Chalk Rock bed”, was
regarded as the direct equivalent of the Chalk Rock. Up to 1889
it figured as the top bed of the zone of 7. data, but in that year
Strahan? included it in his ‘‘ Upper Chalk”’, and so impliedly, if not
directly, in the zone of H. planus.
In 1903 Jukes-Browne? drew the boundary between these zones
at the ‘‘Grey Marl’”’ on the grounds that Holaster planus and
Micraster Leskei do not become abundant until we get above it, and
that it was uncertain whether any specimen or fragment of Micraster
had up to then been found below it. In 1908 these arguments were
almost annihilated by Rowe, who recorded that Holaster planus was
as common below the ‘‘Grey Marl’? as above it, and that Dlcraster
in the shape of JZ. cor-bovis was by no means rare below it—observa-
tions which entirely accord with my own. He transformed the
observation about Micraster Lesket by the statement that it did not
occur at all until above the ‘‘ Bicavea bed’’, but he, too, adopted
the conclusion that the base of the zone of Holaster planus was the
‘‘Grey Marl” on the grounds that Lehinocorys scutatus, Micraster
Leskei, and Micraster precursor do not occur below it.* I have no
reason to dispute these statements, but their force as arguments in the
above connexion is quite another matter. On p. 221 we find that
neither did Wf. Leskei or M. precursor occur in the first bed above the
‘Grey Marl” (i.e. the ‘‘ Bicavea bed”’), and only one specimen of
E. scutatus was found there. Now the ‘‘ Bicavea bed” is unique
in its quality of breaking up into blocks, which, owing to the
presence of a marl seam both above it and below it, contain no element
of any other bed, and whose horizon ean be exactly determined
owing to the ubiquity in it of Brcavea rotula. The result is that the
surface of this bed which is available for study under the most
favourable conditions is only limited by the number of blocks of it
lying above wavewash on the falls of Culver Cliff and in Compton
Bay, and its total area must be estimated in thousands of square
1 The Geology of the Isle of Wight (Mem. Geol. Surv.), 1889.
2 The Cretaceous Rocks of Britain (Mem. Geol. Surv.), pt. iii, 1904.
3 Op. cit., p. 220.
hk. M. Brydone—Chalk Zone of Holaster planus. 247
yards. Under these circumstances the finding of a single specimen
of Z. scutatus is devoid of any serious significance, and when it figures
as the sole reason for making a separation, not merely in zone but in
stage, between the ‘‘ Brcavea bed” and the ‘‘ Vectensis bed’’, it is
obviously so inadequate that it would be outweighed by the slenderest
grounds for uniting these beds zonally. We are naturally led to ask
whether there are any such grounds.
Accurate collecting from the “ Vectensis bed”’ can only be carried
on over the very limited area, probably not as much as 100 square
yards all told, exposed in situ, as there is no outstanding feature by
which fallen blocks from this bed can be certainly identified with it.
I have only examined it once at Culver Cliff and twice at Compton
Bay, but I have obtained from it besides other fossils the following
significant ones :—
Holaster planus (abundant).
Pentacrinus (large ossicles in abundance).
Bourgueticrimus (joints in great abundance, many long and slender).
Lophidiaster ornatus (ossicles in abundance).
Crama Egnabergensis (several).
Lima Wintonensis (several).
Scalpellum maximum.
Polyzoa of twelve genera, most of which are represented by more than one
species, including Membranipora Vectensis and Bicavea rotula.
Every item in this list is a strong link with the zone of Holaster
planus and a strong distinction from the typical chalk of the zone of
T. lata in the Isle of Wight at any rate. They must, of course, be
taken quite strictly. A solitary specimen of Lima Wintonensts or
Crania Egnubergensis would be unexpected without being startling
in the typical 7. Jata-chalk of the Isle of Wight, but several
specimens of either would compel a reconstruction of our ideas about
that chalk. ‘They are regular constituents of the H. planus-fauna,
as also (at Compton Bay only) is Scalpellum maximum. Lophidiaster
ornatus, which is fairly abundant in the Albian, is also known from
the Chalk zones of H. subglobosus, T. lata, H. planus, and Micraster
cor-testudinarium, but while it is abundant and very widespread in
the zone of H. planus it is quite scarce in the other zones. Ossicles
of Pentacrinus (to use the familiar name for convenience, not in
ignorance of Dr. Bather’s correction) are not of course per se peculiar
to the zone of H. planus. I have them from every zone of the White
Chalk, but the zone of H. planus is the only one beside that of
B. mucronata in which they are not both scarce and small. Those
of the ‘‘ Vectensis bed’’ are as abundant as those of the H. planus-
chalk and range freely up to 3in. in diameter. Ossicles of
Bourgueticrinus are not unknown in the typical 7. data-chalk of the
Isle of Wight, but my experience is that they are scarce throughout
and always short and stout in the upper part; inthe lower part they
may be long, but are never slender; those of the H. planus-zone
agree absolutely with those of the ‘‘ Vectensts bed’’. Holaster planus
might occur in the typical 7. Jata-chalk of the Isle of Wight, but it
would take a long time to find a second specimen, and an abundance
of it is hardly imaginable. Finally, Polyzoa, numerous both in
species and individuals, forbid any association of the ‘‘ Vectensis bed”
y
248 Rk. M. Brydone—Chalk Zone of Holaster planus.
with the typical 7. Jata-chalk of the Isle of Wight. The presence
of Bicavea rotula (paralleled inland by a specimen recorded at Arreton
by Rowe himself’) should alone be enough to deter anyone from
keeping this bed out of the zone of H. planus in order to attach it to
the zone of Z. data; and you might search the typical 7. /ata-chalk
of the Isle of Wight or any other South English district I am
acquainted with for days without finding a single specimen of any
Polyzoon, while Polyzoa are of course thoroughly characteristic and
abundant features of the Senonian. The combined effect of these
points seems to make an overwhelming case for uniting the ‘‘ Vectensis
bed”? with the Senonian zone of Holaster planus in preference to the
Turonian zone of Terebratulina lata.
Once the Senonian character of the ‘‘ Vectensis bed” has been
established the position of the ‘‘ spurious Chalk Rock bed’? becomes
an open question. The bed itselfis so hard and the area of it exposed
am situ so small that paleontology is not likely to give much help.
Its peculiar physical characters, striking as they are, cannot be relied
upon for identifying fallen blocks, as there is, at Culver Cliff at any
rate, a very similar bed in the zone of JL, cor-testudinarium. It is to
be noted, however, that H. planus is recorded from it, which is at any
rate some argument in the Isle of Wight for attaching it to the zone
of that fossil, and I have two specimens from it of the Polyzoon
Onychocella Lamarcki, which is no ordinary fossil of the 7. data-chalk.
The lithological evidence is all in favour of the same course. ‘here
is the widest difference between this bed and the typical Z. lata-
chalk, while there is a considerable affinity between it and the
nodular and hard H. planus-chalk above. I come, therefore, to
the conclusion that the ‘‘ Vectensis bed”? and the ‘‘spurious Chalk
Rock bed”? should both be placed in the zone of Holaster planus, and
that the boundary between that zone and the zone of 7’ data in the
Isle of Wight should be drawn at the violent change from a long
period of very uniform conditions of deposit which would seem to be
marked by the appearance of the ‘‘ spurious Chalk Rock bed”.
It will be obvious that this conclusion cannot leave Dorset
unaffected. The Dorset coast sections embracing the base of the
zone of H. planus are, with the exception of the hopeless section in
Durdle Cove, singularly inconvenient for access and very limited
in area at the best. But it seems quite clear, from my own observa-
' tions and those of Rowe,” that all along the Dorset coast a substantial
thickness of typical 7. Jata-chalk is followed by a sequence for all
practical purposes identical with that of the Isle of Wight; and the
objections to associating either the relatively very fossiliferous chalk
above the ‘‘spurious Chalk Rock bed”’ or the ‘‘spurious Chalk Rock
bed” itself with the alien chalk below are of the same character as
in the Isle of Wight, and, considering the nature of the exposures,
equally strong.
The paleontological and lithological evidence can obviously in the
Isle of Wight and apparently in Dorset be harmonized by taking the
presence of Holaster planus as the test of the beginning of the zone
Ops cits pp.263-
2 Op. cit., pt. ii, 1901,
Herbert L. Hawkins—Studies on the Echinoidea, etc. 249
_ of that fossil. If itis to be found at all in the typical 7. Jata-chalk
it is a most exceptional occurrence, while it is found in the first bed
above the typical 7. data-chalk (the ‘‘ spurious Chalk Rock bed”) and
oceurs freely in the next (the ‘‘ Vectensis bed”). Jlicraster is a broken
reed for this purpose. Even Rowe includes in the zone of H. planus
8 feet of chalk (the ‘‘ Bicavea bed”) in which he recognizes the
absence of his test Micrasters for that zone, J/. Lesker and IL. cor-
testudinarium (precursor shape).
In conclusion I should like to point out that my statements as to
the absence or rarity of certain fossils in the zone of 7. data in the
Isle of Wight (or elsewhere) cannot. be tested by reference to any
lists which do, like those of Rowe & Jukes-Browne, or may, record
the fossils of the ‘‘Vectensis bed’’ or corresponding beds under the
zone of J. lata. I have, for my own part, relied on my general
experience of typical Z. Jata-chalk in the South of England,
supplemented by an examination made expressly for this purpose of
the exposures at Compton Bay and Culver Cliff on occasions when
they were in excellent condition.
I1].—MorpnonoeicaL Srupies on tHE Ecurnoipna HoLecryporpaA AND
THEIR ALLIES.
By HERBERT L. HAWxINS, M.Sc., F.G.S., Lecturer in Geology, University
College, Reading.
III. Some yarrarions In THE SrRucruRE oF THE APICAL SYSYEM OF
HT OLECTYPUS.
(PLATE XVI.)
1. InrRopuctrion.
gunverenst variation, unless due to injury or disease, may be
regarded as a sign of racial health. ‘The plasticity that allows
or encourages deviation from the normal is an indication that the
race is still young and vigorous, and that the deadening and
ultimately fatal phase of stereotyped ‘‘ perfection’? has not been
reached. The younger the race the more variable are even vital
structures. It may be surmised that the several stages of race-life
can be classified by the quantity and quality of variability shown.
Indeed, variation, however induced or employed, is the determining
force of evolution. Variants must therefore be considered as tentative
and experimental efforts whose direction is parallel, or coincident,
with the trend of evolution of the group. They can be used as
indices of phylogeny that afford evidence of the ancestry, and also
of the posterity, of their own and related stocks.
The recent work of R. T. Jackson on the relative positions of the
ocular and genital plates in the apical systems of many Regular
Kchinoids, has brought to ight abundant and convincing proof. that
a species consists of a ‘‘norm” surrounded by a series of regressive
(or arrested) and progressive variants.’ It has also been shown
1 See especially ‘‘ Phylogeny of the Hchini ’’ and ‘‘ Studies of Jamaica
Kchini’’.
250 Herbert L. Hawkins—Studies on the Echinoidea, ete.
conclusively that the actual position of the norm between the
extremes of variation differs in separate localities, resulting in local
‘varieties’? which might be expected to extend their divergence
until a distinct series of ‘‘ species”? was differentiated. A sufficient
compilation of records would make possible a fairly confident
prediction as to the main characters of these future species.
In the study of paleontological material there is often an
opportunity to make actual observation of the ancestry and
descendants of a particular species, and so it becomes possible
to correlate the variations of that species with the known trend of
evolution in the group to which it belongs. Conversely, an analysis
of the variations may give suggestive evidence of relationships.
I have been able to examine a considerable number of specimens of
the common Inferior Oolite form, Holectypus hemisphericus, from two
localities in South-Western England. The results, in so far as they
depend upon the structure of the apical system, seem sufficiently
striking to be worthy of record. It must be remembered, however,
that these results are based upon a study of some scores of
individuals, while Jackson’s are derived from hundreds or even
thousands. The percentage calculations would be liable to con-
siderable change when made from larger numbers.
In 1912 I showed, in this Magazine (Dec. V, Vol. IX, p. 8), the
extreme diversity of structure met with in the apical system of
the Holectypoida. Within the limits of the order there exists
a record of the various methods whereby the readjustments,
consequent on the backward migration of the periproct, were
effected. The phylogenetically recent date of this disorganization
rendered the apical system peculiarly sensitive to variation, and
it was only in the later members of the order, and in descended
stocks, that any fixity of structure was attained. The Bathonian
species of Holectypus, though far in advance of Plescechinus (in the
repair of the apical system), are sufficiently near in time to the
presumably Liassic origin of the order to exhibit much instability
of apical structure. It would be interesting to examine a large
series of H. depressus (the Inferior Oolite contemporary of H. hemi-
sphericus), so that a comparison could be made in this matter
between the two strikingly distinct species. If any Cotteswold
collectors who have a series of H. depressus would enable me to
examine their specimens, I should be very grateful for the
opportunity. Large numbers from one horizon and locality are
required for useful results.
2. HoLtecrypus HEMISPHARICUS.
This well-known species is extremely abundant in the upper part
of the Inferior Oolite (particularly in the schlanbachi-hemera) of
Dorsetshire. Its distribution is peculiar. As Richardson has shown,
it is scarce, and often absent, in the Cotteswold district, flourishing
only to the south of the Mendip axis. Its place in the more
northerly region is taken by the small H. depressus, which, in its
turn, is excessively rare in the south. In many parts of Dorsetshire
H. hemisphericus and Pygorhytis ringens vie with one another in
Herbert L. Hawkins—Studies on the Echinoidea, etc. 251
abundance, and sometimes threaten the supremacy of the all-pervading
Terebratula (Spheroidothyris) ‘‘ spheroidalis”’. :
The specimens of H. hemisphericus are commonly small, averaging
2 cm. in diameter, and are remarkably uniform in size. It is easy,
therefore, to collect plentiful material for a study of variation,
without the complication of differences due to age. For the purposes
of the present paper (which is only a preliminary note) specimens
from two localities have been used, and no others are referred to, so
as to avoid confusion. In a collection in the Manchester Museum
there are twenty-two specimens (suitable for study) labelled
‘‘Broadwindsor’’; all, apparently, from one quarry. In my own
collection there were 167 specimens from a layer about one foot thick
in a quarry on the side of the main road east of Bridport. Many of
the latter series have been broken up or otherwise disposed of in the
course of other work upon them, but examples of all observed types
of variation have been retained.
Taking the 189 specimens together, the normal structure of the
apical system (occurring in 55°5 per cent) is that represented by
Pl. XVI, Fig.2. But owing to the disparity in the numbers from the
two localities, this combined percentage is misleading. The true
relations of the ‘‘norms”’ and ‘‘ variants” may be more satisfactorily
expressed by means of the following table :—
Apical t i
Total Be Pe ore Aberrant
Mecaitye | ne. ))| PIL KVEy wie 1. | PI XVi, Hig, 2. oma.
Specimens. No. of, No. of No. of,
Broadwindsor . 22 12 55 4 18 6 27
Bridport . . 167 32 19 101 61 34 20
From this table it appears that there are separate ‘‘norms”’ for
the two localities, although the small number of the Broadwindsor
specimens is unfortunate. Fifty-five per cent of the Broadwindsor
forms have a type of apical system which is found in only 19 percent
of those from Bridport. And conversely 61 per cent of the Bridport
examples possess a structure found in only 18 per cent of those from
Broadwindsor. The percentage of aberrant types from both localities
is surprisingly high.
(a) The Broadwindsor norm. (Pl. XVI, Fig. 1.)
The distinguishing character of this type of apical system depends
upon the direction of the long axis of genital 2 (the madreporic
plate). This axis is at an angle of between 80° and 75° to the
antero-posterior axis of the test. The five genital plates are all
subequal, but plate 1 is somewhat reduced. Owing to the direction
of elongation of plate 2, plates 3 and 5 meet along a short transverse
suture, so that plate 4 is not in contact with plate 2. The ocular
plates are of considerable size, and are all approximately similar.
252 Herbert L. Hawkins—Studies on the Echinoidea, ete.
(b) The Bridport norm. (Pl. XVI, Fig. 2.)
Here the long axis of the madreporic genital is inclined at an
angle of between 60° and 55° in relation to the antero-posterior axis.
The genital plates are subequal, but plate 3 is somewhat reduced.
Owing to the obliquely transverse extension of plate 2, plates 3 and
5 are widely separated from one another, and plate 4 meets plate 2
along a slightly curved suture of some length. The oculars are
similar to those of the Broadwindsor type.
Among the twelve Broad windsor specimens, and thirty-two Bridport
specimens, that conform to Fig. 1, there are, of course, numerous
trifling differences in the proportionate sizes of the plates and the
angles of the sutures, but none of these differences affect the relation
of the plates to one another. The same remark applies to the 4 and
101 specimens represented by Fig. 2. The two figures are copies
of specimens that show the average characters for the respective
types. Since the axis of the madreporic genital of Plesiechinus is
almost parallel to the antero-posterior axis, and that of Conulus
considerably inclined, the Bridport norm would seem to be progressive
beyond the Broadwindsor type.
(c) The aberrant forms.
Beside the two alternative structures in the apical system above
noted, there are three classes of variants that show more striking
departures from the normal. These classes are illustrated by Pl. XVI,
Figs. 3, 4, 5, and 6.
(1) Variant 1. (Pl. XVI, Fig. 3; ef. also Figs. 6, 7, and 8.)
This variation, which consists in the transgression of the madre-
porite on to genital 3, is by far the commonest type of abnormality
in the series examined, and among other Holectypoids as well. Of
the six aberrants from Broadwindsor five possess this character; one
of them (Fig. 6) combining with it a different type of variation.
Of the thirty-four aberrants from Bridport, no fewer than thirty-two
possess a similar character. The five Broadwindsor specimens are all
‘‘norms”’ for their locality as regards the relations of the genital
plates, but, as a comparison of Figs. 1 and 3 will show, the pro-
portions of the plates are various. Thirty of the Bridport specimens
have the ‘‘ Bridport norm” in plate relations, the other two being
like those from Broadwindsor.
I have not seen any specimens of H. hemisphertcus in which the
madreporic perforations extend on to any other plate than genital 3.
Variants of this character, often carried to a further degree, are by
no means uncommon in Conulus (Pl. XVI, Fig. 8). In the specimen
figured all four genital plates are perforated by the madreporite, but
it is only on plate 3 (of the abnormal ones) that the pores are at all
abundant.
In Discoides the extension of the madreporite on to all five genital
plates is a generic character (Pl. XVI, Fig. 7). The variants of
Holectypus of the type under consideration may then be considered
to be progressive in the Discoides direction, while the similar variants
+ the’ a eR DY A
tan ; ; Ra aha (a PA
o foe
; Sz
real te 9. of ays
: oo ierbert L. Hawkins—Studies on the Echinoidea, etc. 253
in Conulus might be called ‘‘ parallel variants’’, on the supposition
that there is no direct phyletic sequence between Conulus and
Discordes.
(2) Variant 2. (Pl. XVI, Figs. 4 and 5; cf. also Figs. 6 and 9.)
One specimen from Broadwindsor (Fig. 5) and two from Bridport
(Fig. 4) show the development of a supernumerary plate more or
less midway between genitals 2 and 5. In both the Bridport forms
this is small and pentagonal, having sutural connexion with all the
genitals except plate 4. (Both specimens have the ‘‘ Broadwindsor”’
arrangement of the genital plates.) In the Broadwindsor specimen
the supernumerary is large and hexagonal, and, being in contact with
all five genitals, acts as a kind of “centrale’’. ‘There is no evidence
to prove that this included plate is not really genital 5, while the
plate in the posterior region is the additional one; but it seems
more reasonable to suppose that the appearances are not deceptive,
and that the internal plate is actually the supernumerary.
Additional internal plates within the true cycles of the apical
system occur in the Calycina among Regular, and in some of the
Clypeus—Nucleolites series of the Irregular, Echinoids. This distri-
bution of supernumeraries opens up an interesting speculation when
applied to the variants under notice. _Acrosalenia is an ancient, and in
most respects, primitive member of the Diademoida (Centrechinoida),
and may well have originated collaterally with the Holectypoids in
Liassic times, even if it is not on their line of descent. So that
a comparison of the aberrant Holectypus with Acrosalenia would class
the variation in the former as either arrested (or regressive) or
perhaps ‘‘arrested parallel’’. In the case of ‘‘ Wueleolites”’ (as illustrated
by ‘‘ WV.” orbicularis (P1. XVI, Fig. 9), a considerable number of more
or less symmetrically placed supernumeraries occurs posteriorly to the
large madreporic genital. In Fig. 9, as I interpret it, plate ¢ (the
most posterior) represents genital 5, and either 5 or a might be
correlated with the additional plate in Holectypus. In view of the
- fairly certain primitiveness of Holectypus, and the equally probable
lack of direct sequence from that genus to the Nucleolitide, a com-
parison of the two would class the variant as an imperfectly
‘“ progressive parallel’’. This comparison will appear less far-fetched
when the next section has been read.
(3) Variant 3. (Pl. XVI, Fig. 6; cf. also Figs. 8 and 9.)
This solitary specimen from Broadwindsor shows a very striking
abnormality. In the first place, it possesses the characters of variant 1,
in that the madreporite is partly situated on genital 3.4 here is
a ‘‘centrale’’-like, hexagonal, imperforate plate a little behind the
centre of the system, approximately similar in area to the two
genitals (1 and 4) that flank it. Behind this included plate the
two posterior oculars (I and V) meet. Both are enlarged and dis-
torted in shape, but plate 1 is by far the larger of the two. There
is thus no posterior genital (5); at least, as concerns the margin of
the system. At first I was of the opinion that the included hexagonal
plate was actually the fifth genital shifted anteriorly. But in view of
254 Herbert L. Hawkins—Studies on the Echinoidea, ete.
the structures observed in variant 2, I now incline to the belief that
the included plate is a supernumerary, and that genital 5 is wanting.
If this is a correct interpretation of the specimen, it would prove to
be similar to variant 2 in this respect as compared with Acrosalenia
or ‘‘ Nucleolites’”?. On comparing oculars [ and V in Figs. 6 and 9,
a certain resemblance in their distorted shape and increased length is -
seen. In this respect also the Holectypus variant can be considered
as ‘‘ progressively parallel”’ to the ‘‘ Wueleolites’’ norm.
A comparison between Figs. 6 and 8 (Conulus) is perhaps more
satisfactory. The generic character of the Conulus apical system is
the absence of the fifth genital and the consequent meeting of the
posterior oculars, I and V. It is seen that in both figures these
oculars are much enlarged. Although in the Holectypus, ocular I is
the larger of the two, while the reverse is the case in the Conulus,
the discrepancy is more apparent than real. Other specimens of
Conulus (both C. subrotundus and C. albogalerus) have ocular I larger
than ocular V. The less usual type was chosen for figuring because
of its possession of the characters of variant 1. It will be readily
seen that if the supernumerary plate in the Holectypus were removed
the consequent readjustments would bring genitals 1 and 4 into
contact (as they are in Conulus); and a very slight alteration in the
dimensions of genital 2 would produce an almost exact similarity
between the two systems. When it is realized that in Holectypus
depressus (see Fig. 11) genital 2 may be in contact with ocular IV
(as is the case in Conulus), the correspondence between the two
structures becomes more obvious.
Thus while the included supernumerary plate and the posterior
oculars (in the variant illustrated in Fig. 6) show an inclination
towards the JVucleolites character, the absence of genital 5 and the
meeting of oculars I and V indicate a very definite ‘‘ progressive ”’
variation towards Conulus. Whatever may be the ancestry of the
last-named genus, its line of descent cannot have been remote from
that of Holectypus.
3. Hoxecryrus pepressus (Cornbrash). (Pl. XVI, Figs. 10 and 11.)
Although I have not enough specimens of this large and abundant
species (which is surely specifically distinct from the small Inferior
Oolite form of the same name), there are two types of apical system
shown in the few examples at my disposal. The madreporie genital
(2) is always large in this species, and the madreporite occupies
a prominent position in the centre of the system. In six specimens,
ranging in diameter from 2 to 5 cm., the plates are arranged as in
Fig. 10. Using a terminology analogous to that employed by
Jackson for Regular Echinoids, this type may be said to have
oculars I, II, and III ‘‘ insert’ (to the madreporite instead of to the
periproct), and oculars IV and V ‘‘ exsert”’. (By a similar argument
H. hemisphericus has only oculars II and III ‘“‘insert”’.) But im
one medium-sized specimen (Fig. 11), with a diameter of about
3-5 em., genital 2 is so enormously expanded that the remaining
genitals are much reduced in size, and all five oculars are ‘“‘insert”’,
being in contact with the madreporic plate. The specimens are
er)
oe:
o
7
a .
tho
Geox. Maac., 1917. PLath XVI.
H. L. H., del.
NORMAL AND ABNORMAL APICAL SYSTEMS OF HOLECTYPUS
AND OTHER GENERA.
Herbert L. H awkins—Studies on the Echinoidea, etc. 255
all from the same locality, and those of the remaining six that
approximate to the size of this specimen have the characters of
Fig. 10. So there are indications that another series of variants
could be traced in this species. The original of Fig. 11 cannot be
regarded as progressive towards the Corallian species (H. oblongus,
Fig. 12), for in six specimens of that form, from Upware, the ocular
‘‘insertion”’ is identical with that of the Cornbrash ‘‘norm”’. The
contact between genital 2 and ocular 1V in this specimen sucgests
comparison with the conditions in the apical system of Conulus
(Fig. 8), but that feature, and the large size of the madreporic
genital (not a variant character) are the. only ponies of resemblance
between the two.
4, SuMMARY.
The characters of the apical system of a series of bier
hemisphericus from the same horizon at two localities in Dorsetshire
are analysed and described. It is found that the average relations
of the plates of the system are different at the two localities,
although certain numbers of identical forms occur at both. Out of
~ 189 specimens (from both localities), 40 show serious departures
from the normal type. ‘These abnormalities are of three classes.
One, the most prevalent, consists in the presence of madreporic pores
on genital 3, in addition to the normal perforation of genital 2.
This is regarded as a ‘‘ progressive variant’? in the direction of
Discordes. ‘The second, occurring in three specimens, consists in the
interpolation of a supernumerary plate within the system. It is
suggested that this may be either a ‘‘ regressive variant”? towards
Acrosalenia, or a ‘progressive variant” towards Wueleolites (as
illustrated by LV. orbicularis). In neither case would this variation
eoincide with actual phyletic sequence, so that it is styled ‘‘ parallel
variation”’. The third type of variant, seen in one specimen only,
combines both the first and second types, and in addition shows
an absence of genital 5 and a corresponding increase in the size
of the posterior oculars, which meet round the back of the system.
' The variation in this specimen is interpreted as being ‘‘ progressive ’”
towards Discordes, ‘‘ parallel progressive’’ or ‘‘regressive”’ towards
Nucleolites or Acrosalenia respectively, and ‘‘ progressive”’ towards
Conulus. There are indications of a different series of variants in
the Holectypus depressus from the Cornbrash. The high percentage
of variation in the composition of the apical system of Holectypus is
regarded as an indication of the evolutional activity of the genus,
and of its near approximation in time and phylogeny to the common
origin of many of the groups of Irregular Echinoids.
EXPLANATION OF PLATE XVI.
All figures are considerably magnified, and are brought to a uniform size for
convenience of comparison. All are viewed from the outside of the test, so
that the numbering of the plates is in an anti-clockwise direction.
Fic.
1. Holectypus henisphericus. Broadwindsor. The normal apical system
for this locality. Genitals 3 and 5 in
contact.
a A Bridport. The normal apical system for this
locality. Genitals 3 and 5 separated by 2
256)" W. D. Lang—Cheilostome Polyzoa.
FIG.
3. Holectypus hemisphericus. Broadwindsor. Variant 1.
A, a aye Bridport. Variant 2.
5 ne an Broadwindsor. Variant 2.
6. a Mi Broadwindsor. Variant 3.
7. Discoides cylindricus. Wallingford. Normal apical system.
8. Conulus subrotundus. Reigate. Cf. variant 1.
9. Nucleolites orbicularis. Rushden. ? Normal apical system.
10. Holectypus depressus. Rushden. Oculars I, II, and III “‘insert’’.
Ae i, Same locality. All oculars ‘‘ insert’’.
12. i oblongus. Upware. Normal apical system.
ITV.—On some NEW CENOMANIAN AND TurRonIAN CHEILOSTOME
Ponyzoa.
By W. D. Lane, M.A.
(By permission of the Trustees of the British Museum.)
(PLATE XVII.)
Tiapstpopora, new genus.
(7 avis, ‘ an arch,’ in reference to the hoop formed proximally to
the aperture. )
Diagnosis.—Asty incrusting, uniserial, with bilateral and unilateral
branching ; cecia dimorphic; normal cecia with short caude or without
caude ; pyriform; termen a complete, high, narrow, oval ridge with
few small spines on its circumference and, at the proximal-lateral
corners of the aperture, a pair of stout spines which sometimes, if
not always, bend towards one another and fuse in the middle line ;
apparently there are no spines around the distal end of the aperture ;
extra-terminal front-wall well-developed proximally, and arched ;
intra-terminal front-wall a wide, depressed lamina; aperture oval,
sub-quadrate, somewhat constricted laterally; avicularia small, one,
-or a pair, placed laterally and somewhat distally with regard to each
aperture, rather abruptly pointed with the distal ends curved towards
the aperture they encompass; ovicells hyperstomial.
Genotype.—Hapsidopora arcuata, n.sp.
Remarks.—It is noteworthy that the terminal ring of Hapsidopora
is complete proximally, and not smoothed away as in so many other
forms with a wide lamina.
Key to the genus Hapsidopora.
A. Pair of spines at the proximal-lateral corners
of aperture not so stout, and the terminal
spines proximal to these larger than in
HT. arcuata : , ‘ ; 4 . 1. A. harmeri.
B. Pair of spines at the proximal-lateral corners
of the aperture very stout and arching over,
fuse with one another in the mid-line;
terminal spines proximal to these smaller
than in H. harmert . ‘ : : . 2. H. arcuata.
EE eee ore eee
W. D. Lang—Cheilostome Polyzoa. Dov
Hapstpopora HARMERI, n.sp. Pl. XVII, figs. 1 and 2.
(As a mark of respect to my colleague and former teacher, Dr. S. F.
Harmer.)
Diagnosis.— Hapsidopora with comparatively large terminal spines,
and the spines in the proximal-lateral corners of the aperture
smaller than in H. arcuata; the terminal ring makes a narrower
ellipse; the avicularia are slightly slenderer than in H. arcuata.
Type-specimen.—British Museum specimen no. D. 21673; Ceno-
manian, Chalk Marl, 20 ft. from the base; Cambridge; F. Mockler
Coll.
Hapsipopora arcuata, n.sp. Pl. XVII, figs. 3 and 4.
(Arcuatus, ‘arched,’ in reference to the hoop-like structure proximal
to the aperture.)
Diagnosis.—Hapsidopora with very small terminal spines and
a very stout pair of spines at the proximal-lateral corners of the
aperture; the terminal ring makes a wider ellipse; the avicularia
are somewhat stouter than in HZ. harmert.
Type-specimen.—British Museum specimen no. D. 22871; Ceno-
manian, Chalk Marl, 20 ft. from base; Cambridge; F. Mockler Coll.
TyLopoka, new genus.
(6 7UNos, ‘a knob,’ in reference to the beaded termen.)
Diagnosis.—Asty incrusting, pauciserial and branched; at each
branch an uniserial stage is nearly or quite resumed, though some-
times a lateral bud from an cecium of one branch curves away and
joins the other branch; cecia dimorphic, with unilateral budding,
elliptical with tapering proximal ends, but no caude; termen plain
or with minute spines, to beaded; extra-terminal front-wall present
only at the extreme proximal end of the cecium; intra-terminal
front-wall a wide, depressed, proximal lamina prolonged on each
side in lateral terminal bevels; aperture circular to oval; renewed
cecia abundant; avicularia small, blunt, generally one, sometimes
a pair placed distally and somewhat laterally to each cecium.
Genotype.—Tylopora lorea, u.sp.
Key to the genus Zylopora.
A. Termen plain, or with minute spines . . 2. ligatrix.
B. Termen beaded.
1. Cicia shorter (about °6 mm) and blunter
distally . : : 4 3 . 2. mower,
2. Cicia longer (about ‘8 mm) and more
pointed distally . . : : . I” lorea.
TYLopora LIGATRIX, n.sp. Pl. XVII, figs. 5 and 6.
(Ligator, ‘a binder,’ invented from Jigare ‘to bind’, from the strap-
shaped asty.)
Diagnosis.—Tylopora with a plain termen, or, if spines are present,
these are exceedingly small.
Type-specimen.—British Museum specimen no. D. 29205; in-
erusting Conulus subrotundus Leske. [Turonian, zone of R. cuviert | ;
Burham, north-west of Maidstone, Kent. Coll. Hon. R. Marsham.
DECADE VI.—VOL. IV.—NO. VI. 17
258 W. D. Lang—Chevlostome Polyzoa.
TYLopoRA ROWEI, n.sp. Pl. XVII, figs. 7 and 8.
(As a mark of regard to Dr. A. W. Rowe, who kindly lent me the
type-specimen for description. )
Diagnosis.—Tylopora with a beaded termen, and short (about 6 mm.
long) rather blunt cecia.
Type-specimen.In the collection of Dr. Rowe of Margate;
incrusting Infulaster excentricus (S. Woodward) ; Turonian, zone: of
Terebratulina; Norfolk.
TyLopoRa LoREA, nsp. Pl. XVII, figs. 9,10 and1l. |
(Loreus, ‘made of thongs,’ in allusion to the strap-shaped asty.)
Diagnosis.—Tylopora with a beaded termen, and longer (about
-8 mm.) and rather more pointed cecia.
Type-specimen.—British Museum specimen no. D.15389 ; Turonian,
zone of Holaster planus; Church Top Pit, South Elkington, west of
Louth, Lines; Coll. C. 8. Carter.
EXPLANATION OF PLATE XVII.
FIG.
1. Hapsidopora harmeri, n.sp. Portion of the type-specimen, showing
bilateral and unilateral branching. x about 34 diameters. British
Museum specimen no. D. 21673. Cenomanian, Chalk Marl. Cambridge.
F. Méckler Collection.
2. Hapsidopora harmeri, n.sp. A single cecium—the distal-most—of the
part of the type-specimen represented in fig. 1. x about 50 diameters.
3. Hapsidopora arcuata, n.sp. Portion of the type-specimen, showing
bilateral and unilateral branching. The most proximal ccium is
arenewed ccium. x about 26 diameters. British Museum specimen
no. D. 22871. Cenomanian, Chalk Marl. Cambridge. F. Méckler
Collection.
4, Hapsidopora arcuwata, n.sp. A single cecium from another part of the
type-specimen than that represented in fig. 3. x about 40 diameters.
5. Tylopora ligatriz, n.sp. Portion of the type-specimen. x about
26 diameters. British Museum specimen no. D. 29205. [Turonian,
zone of Rhynchonella cuvieri.| Burham, Kent. Hon. R. Marsham
Collection.
6. Tylopora ligatrix, n.sp. A single cecium—the most distal on the right-
hand side—of the part of the type-specimen represented in fig. 5.
x about 40 diameters.
7. Tylopora rowei, n.sp. Portion of the type-specimen. X about 26 diameters.
Turonian, zone of Terebratulina. Norfolk. In the collection of
_ Dr. A. W. Rowe.
8. Tylopora rowei, n.sp. A single cecium—the most distal on the right-hand
side—of the part of the type-specimen represented in fig. 7. x about
40 diameters.
9. Tylopora lorea, n.sp. Portion of the type-specimen, showing a branch.
Five of the cecia are renewed ecia, and four are closed wcia; the
remaining ccium (on the left, proximally) is normal. x about
26 diameters. British Museum specimen no. D. 15389; Turonian,
zone of Holaster planus. South Elkington, Lincs. C. §. Carter
Collection.
10. Tylopora lorea, n.sp. A single ecium, the only normal one in the portion
of the type-specimen represented in fig. 9, namely that on the left-hand
side and proximally situated. x about 40 diameters.
11. Tylopora lorea, n.sp. A single renewed cecium—just proximal to the
middle—of the part of the type-specimen represented in fig. 9. Xx about
40 diameters.
| Guon.’ Mac., 1917. Prare XVI.
G. M. Woodward, del.
HAPSIDOPORA and TYLOPORA.
Notices of Memoirs—The Lenham Sandstones of Kent. 259
NOTICHS OF IMM IVOTRS-
re SS
I.—Tur ConcHonoeicat Features of THE LenHam SaNnDSTONES OF
Keni, AND THEIR STRATIGRAPHICAL ImpoRTANCE.' By R. Buriien
Newroy, F.G.S., of the British Museum (Natural History).
Para i:
4 T various points along the summit of the chalk escarpment
A forming the North Downe of Kent and Surrey and extending
from Paddlesworth near Folkestone to Lenham near Maidstone, and
thence to Netley Heath between Guildford and Dorking—a distance
east and west of about seventy miles—there occur in pockets, cavities,
or “pipes” of the Chalk formation, certain scattered masses of
a reddish ferruginous sandstone at considerable altitudes above sea-
level; at Paddlesworth this sandstone has been observed at 600 feet ;
at Lenham 680 feet; while at Netley Heath it is found ata height.
of between 570 and 600 feet. Sandstones of corresponding age are
met with in France particularly on the hills between Calais and
Boulogne, and on Cassel Hill near Dunkirk at 515 feet; they also
occur at Louvain (200 feet) and Diest, both in Belgium, the beds of
the latter locality having yielded fossiliferous remains bearing
a resemblance to the Lenham fauna, although often differing in specific
characters.
The more important of these sandstone deposits, so far as this
country is concerned, are those found on the Lenham Downs, as they
contain the remains of a marine fauna, chiefly of conchological
interest, whereas the beds of other districts are generally un-
fossiliferous, although it should be mentioned that a few Mollusca of
rather uncertain character have been obtained from both Paddlesworth
and Netley Heath.
The fossils known in the various museum collections have been
mostly obtained from a large disused chalk quarry situated about
half a mile to the north of Lenham, of which an excellent sketch
' may be consulted in Mr. Reid’s ‘‘ Pliocene” memoir of 1890, showing
the vertical positions assumed by the fossiliferous sandstone pipes
seen in the limestone exposure. It has been generally recognized
that such deposits represent the remnants of a marine Tertiary
formation belonging to early Plocene times, although my own
investigations have led to somewhat different results, and I am more
inclined to refer them to the latest division of the Miocene period.
The organisms occur as casts and cavities in the sandstone, and are
frequently in a fragmentary condition, rendering their determination
extremely difficult. The walls of the cavities, however, often retain
sculpture characters, so that it 1s possible by the aid of wax
impressions to obtain reliable evidence as to external details which
' We have just received in a connected form the complete text of Mr. R. B.
Newton’s valuable memoir ‘‘ On the Conchological Features of the Lenham
Sandstones of Kent, and their stratigraphical importance’’. This paper formed
the subject of his Presidential Address to the Conchological Society of Great
Britain and Ireland at Manchester, on October 16, 1915, and was afterwards
printed in four parts in the Jowrnal of Conchology, vol. xv, 1916-17, making
64 pages, with 4 plates of Mollusca. With the author’s kind permission we
give an abridged notice.
260 Notices of Memoirs—R. Bullen Newton—
may be safely used for purposes of identification. ‘To Mr. Clement
Reid, F.R.S., we are mainly indebted for most of our later knowledge
of the Lenham fauna, his researches forming part of the ‘‘ Pliocene ”’
memoir before mentioned. At that time Mr. Reid had obtained an
important series of fossils from the Lenham Beds for the Museum of
Practical Geology, which, after being determined, were systematically
referred to in the memoir. In order to facilitate my studies on this -
subject and to enable me to determine certain collections of similar
fossils in the British Museum, especially that formed by Mr. Graham
Wallas, I was very kindly allowed to loan this valuable type
collection made by Mr. Reid. During my studies in this direction it
has been necessary to introduce a certain amount of revision, both
among the genera and species as laid down in Mr. Reid’s memoir.
The larger amount of material available at the present time has also
resulted in the determination of additional species, so that the shells
are regarded as numbering 77 species, which include 1 Scaphopod,
32 Gastropods, 43 Pelecypods, and 1 Brachiopod, whereas Mr. Reid’s
conchological list embraced 65 species, consisting of 1 Scaphopod,
27 Gastropods, 36 Pelecypods, and 1 Brachiopod. Among the 382
Gastropods now recognized, a new species has been described under
the designation of Rengiculella lenhamensis. In view of the fact that
no figures have yet been published of Lenham fossils, I have had
prepared some photographs of the more important shell-remains,
which on account of their reddish-brown colour and their more or
less obscure character have not been particularly successful ; yet it is
hoped they may serve a useful purpose in stimulating the interest of
the student who desires to pursue further researches on the conchology
of these little-known beds.
To complete the Lenham fauna I have here briefly introduced
a list of the other organic remains which are found associated - with
the shells :—
PISCES.
Selachian vertebree and a palatal plate as determined by Dr. A. 8S. Woodward.
Coll. B.M.! (Graham Wallas).
POLYZOA.
Fascicularia aurantium, M. Kdwards. Coll. M.P.G., No. 398.
Cupularia canariensis, Busk. Coll. M.P.G., No. 399. B.M. (Graham
Wallas).
ANNELIDA.
Ditrupa subulata, Deshayes, sp. Coll. M.P.G., No. 395.
CRUSTACEA.
[A decapod claw.] Coll. B.M. (Graham Wallas).
Balanus. Coll. M.P.G., No. 396.
ECHINODERMATA. F
Temnechinus (?). Coll. B.M. (Graham Wallas).
Eichinus woodwardi, Desor. Coll. M.P.G., No. 394. B.M. (Prestwich and
Graham Wallas).
Dorocidaris papillata, Leske, sp. Coll. B.M. (Prestwich).
ACTINOZOA.
Trochocyathus(?). Coll. B.M. (Graham Wallas).
1 The author desires to acknowledge his thanks to the authorities of the
Museum of Practical Geology, and particularly to Mr. H. A. Allen, F.G.S., of
that institution, for allowing him access to the ‘‘ Reid ’’ Collection. The letters
B.M. and M.P.G. throughout this work apply respectively to the British
Museum and the Museum of Practical Geology.
rir, = < oe,
NAC wp
The Lenham Sandstones of Kent. 261
In addition to these organisms the Lenham sandstones occasionally
exhibit impressions of the spines of Cidaris clavigera, Konig, and
remains of /noceramus-shell associated with the sponge Cliona, all of
which belong to the Chalk (Senonian) formation, and are con-
sequently of derivative origin. No trace has been discovered in these
beds of any fossils which could possibly have been derived from
Eocene rocks.
Brsriograpay (1857—-1915)."
The history of the Lenham deposits and their fauna was commenced
by the late Sir Joseph Prestwich in 1857,? when reporting the
discovery by W. Harris and Rupert Jones of certain ‘‘ blocks of
gritty ferruginous sandstone, full of casts of shells’’, in some sand-
pipes in the Chalk at Lenham, eight miles east of Maidstone, which
they regarded as belonging to the basement-bed of the London Clay.
Prestwich was familiar with similar sandstones occurring at Paddles-
worth, near Folkestone, at a height of about 600 feet above sea-level,
and at Vigo Hill near Otford in Kent, mentioning likewise that they
were to be found in scattered fragments along the summit of the
North Downs, extending from near Folkestone to Dorking in Surrey ;
but from the fossils he considered that the sandstones were of Lower
Crag age, on account of the presence of a Terebratula resembling
T. grandis, several species of Astarte, and a large Lutraria-like shell ;
this view being also shared by Searles Wood, who had examined the
fossil remains, and recognized the importance of the occurrence of a
Pyrula and an Emarginula as supporting that horizon. Prestwich
also noted that beds of similar structure were present on the hills
between Calais and Boulogne, at Cassel Hill near Dunkirk, and at
Louvain and Diest in Belgium, besides thinking it possible that such
sandstones were connected with the Carentan beds of Normandy.
In the following year Prestwich* again returned to the subject,
aided by Searles Wood. He noticed that many of the species found
_ at Lenham were of southern origin, thus confirming his previous
ideas that the deposits were of Lower or Coralline Crag age. His
determinations of the shells included the following forms :—
SCAPHOPODA.
Dentalium costata (?).
GASTROPODA. ;
Hmarginula reticulata (?). Natica.
Nassa prismatica (?). Rissoa (?).
Scalaria subulata (?). Phorus, related to Trochus cwmularis,
Pyrula. Brong.
Trochus.
' The conchological determinations mentioned in the following memoirs are
those of the authors themselves, without any attempt at a rectification of the
nomenclature.
2**On some Fossiliferous Ironstone occurring on the North Downs’’:
Quart. Journ. Geol. Soc., vol. xiii, pp. 212, 213, 1857.
° “On the Age of some Sands and Iron-Sandstones on the North Downs ”’ ;
with a Note on the Fossils, by S. V. Wood: Quart. Journ. Geol. Soc.,
vol. xiv, pp. 322-35, 1858.
262 Notices of Memoirs—R. Bullen Newton— Bia
PELECYPODA. Tapes perovalis.
Arca lactea (?). Lutraria elliptica.
Pecten avicula (?) and P. bruei. Crassatella concentrica (?), Duj.
Modiola modiola (?). Tellina donacina (?) or Donaz.
Pectunculus glycymeris (?). Mactra triangulata (?).
Nucula nucleus (?). Cardita, Lucina or Diplodonta, Kellia
WN. depressa, Nyst. or Lepton, Isocardia.
Leda lanceolata and L. myalis (?). Venus (?), Anatina, Panopea (?).
Astarte digitaria, A. pygmea, A.
compressa (?), A. omalii (?). BRACHIOPODA.
Cardium (with spines) and C.edule. Terebratula grandis (?).
Cytherea rudis (?).
In the same memoir Prestwich referred to the. occurrence of
similar ferruginous sandstones to those at Lenham on the chalk downs
between Calais and Boulogne, and at Cassel Hillin French Flanders,
515 feet above the sea, overlying the Calcaire Grossier series. It was
mentioned that such beds, although without fossils, had been deter-
mined by Dumont and Lyell as equivalent to the Diestian Sands of
Belgium, which they classed with the English Crag, because the same
sands had been found at Louvain overlying the Limburg and Bolder-
berg strata, containing impressions of shells of Zerebratula grandis,
Solen ensis, and Syndosmya prismatica, besides thirteen genera of
indeterminable species. In a further reference to the Lenham
Mollusca, Searles Wood! mentioned that the Pyrula and Pectunculus
resembled certain sandstone casts from the Red Crag (Box-stone
specimens), although a closer determination was not possible from
their peculiar preservation.
Lyell? recognized the Lenham Beds as of Upper Miocene or
Falunian age, and similar to the Diestian Sands of Belgium, and,
moreover, probably older than the Coralline Crag,
He had traced the Diestian beds, which ‘‘ abound in green grains”’,
from Diest by Louvain and Oudenarde to Cassel in French Flanders
and capping the hills of those places—away to the English Downs
near Folkestone, and appearing at such places as Paddlesworth,
Lenham near Maidstone, etc. He referred to the occurrence in
those beds of Terebratula grandis, casts of Astarte, Pyrula, Emargimula,
which were all common to the British Crag, the first-named being
specially characteristic of the Belgian Diestian.
As a result of an examination of the Prestwich Collection and that
of the Geological Survey, Von Koenen* was of opinion that Lyell
was wrong in his estimate of a Miocene age for the iron-sandstones
of Kent, he regarding them as Pliocene because he considered they
contained characteristic shells of the Upper Crag.
Mr. Whitaker * next gave his opinion on the age of the Lenham
fauna, assisted by Gwyn Jeffreys in connexion with the molluscan
1 “On the Extraneous Fossils of the Red Crag’’: Quart. Journ. Geol. Soc.,
vol. xv, pp. 32-45, 1859.
2 Hlements of Geology, 6th ed., pp. 233, 368, 1865.
3 “Nie Fauna der Unter-oligocinen Tertiarschichten von Helmstadt bei
Braunschweig’’: Zeitsch. Deutsch. Geol. Ges., vol. xvii, p. 461, 1865.
+ “On the Lower London Tertiaries of Kent’’: Quart. Journ, Geol. Soc.,
vol. xxii, p. 430, 1866.
The Lenham Sandstones of Kent. 263
determinations. Their results suggested an Kocene horizon, because
among the fossils was identified a Phorus like P. agglutinans, Cyrena
cunetformis, and a small Mucula like WV. minor.
Bristow ! supported the Kocene age theory for the Paddlesworth
ferruginous sands, which are unfossiliferous, and suggested that they
belonged to the Woolwich and Reading series. In a postscript to
this paper we are informed that the paleontologist W. H. Baily had
examined Lenham fossils and pronounced them to be of London Clay
origin.
In a later paper Von Koenen? regarded the ferruginous sandstones
of Kent as corresponding with the Red Crag on account of the
presence more particularly of Arca lactea, Scalaria foliacea, Emarginula
fissura, and Terebratula grandis.
Writing on the ‘‘ Box-stones”’ of Kast Anglia, Sir Ray Lankester *
thought it very probable they were of the same age as the Lenham
Sandstones; the former he considered as belonging to the Diestian
series of Belgium, and approximately equivalent to the so-called
Black Crag of Antwerp. The Belgian geologist Mourlon* next
recognized that the ‘‘ Sables de Diest’’ occurred on the North Downs
of Kent, between Folkestone and Dorking, Paddlesworth, and
Lenham near Maidstone, as first indicated by Prestwich and Lyell.
Messrs. Cogels and O. Van Ertborn ® alluded to Lyell’s statement as
to the abundant occurrence of Zerebratula grandis in the ironstones
of the North Downs, which was also found in the Diestian beds of
Belgium, this horizon being considered of Lower Pliocene age and
not Miocene as understood by Lyell.
A great advance in our knowledge of the Lenham deposits was next
made by Mr. Clement Reid,® who regarded the beds as Older Pliocene
of Coralline Crag age, and equivalent to the Lower Crag or Diestian
of Belgium. He recognized that the St. Erth Beds were of similar
age and not newer. Speaking of the Lenham Mollusca, he stated that
Arca diluvit was new to England, and that Pleurotoma consobrina (?)
and P. jouanneti (?) were species belonging to the Upper Miocene of
the Continent. His list of determinations, endorsed by Messrs. Shar-
man and EK. T. Newton, included 16 Gastropods, 21 Pelecypods, and
1 Brachiopod.
Four years later fuller particulars of the Lenham deposits were
published by the same author’ in a memoir on the British Phocenes.
They were alluded to as occurring in pipes of the Chalk formation,
1 “*Note on supposed Remains of the Crag on the North Downs near
Folkestone’’: Quart. Journ. Geol. Soc., vol. xxii, p. 553, 1866.
2 ‘On the Belgian Tertiaries’’: GEOL. MAG., 1867, p. 502.
* ‘Contributions to a Knowledge of the Newer Tertiaries of Suffolk and
their Fauna’’: Quart. Journ. Geol. Soc., vol. xxvi, pl. xxxiv, figs. 5-10,
p. 499, 1870.
* Géologie de la Belgique, vol. i, p. 268, 1880.
° “Contribution 4 Etude des Terrains Tertiaires de la Belgique’’: Bull.
Soc. R. Mal. Belgique, vol. xvii, pp. xliii-xlv, 1882.
®° ** The Pliocene Deposits of North-Western Europe’’: Nature, vol. xxxiv,
pp. 341-3, 1886.
‘ The Pliocene Deposits of Britain—Lenham Beds (Diestian) (Mem. Geol.
Sury.), 1890, pp. 2, 42-58, etc.
264 Notices of Memoirs—R. Bullen Newton—
frequently at considerable heights above the sea, near Lenham itself
being found at 680 feet above sea-level. The whole of the British
Pliocene series were grouped into ‘‘ Newer’”’ and ‘‘ Older”’, the latter
containing the following divisions :—
OLDER PLIOCENE.
St. Erth Beds.
Coralline Crag.
Lenham Beds.
Box-stones.
In connection with the Lenham Mollusca it was stated that such
southern genera as /icula (Pyrula), Xenophora (Phorus), Triton, and
Avicula, occurring in association with a profusion of Arca diluvit,
Cardium papillosum, and some South European extinct species of
Pleurotoma and Terebra, represented a fauna in favour of a southern
or Mediterranean origin.
A full list of fossils from the Lenham and other Pliocene deposits
of England was given in tabular order, showing the distribution of
each species in Belgium, France, etc., the Lenham shells alone
including 65 species, made up of 27 Gastropoda, 1 Scaphopoda,
86 Pelecypoda, and 1 Brachiopoda, as follows :—
GASTROPODA.
Acte@on tornatilis, Linnseus.
Aporrhais pespelicani, Linneus.
Buccinum dalei, J. Sowerby.
Cancellaria contorta, Basterot.
Cerithium tricinctum, Brocchi.
Cyprea europea, Montagu.
Hmarginula fissura, Linneus.
Hulima subulata, Donovan (?).
Fissurella greca, Linneus.
Margarita trochoidea, 8. V. Wood.
Nassa prismatica, Brocchi.
Natica millepunctata, Lamarck.
N. varians, Dujardin. |
Pleurotoma consobrina, Bellardi.
P. jouanneti, Desmoulins.
P. turrifera, Nyst.
Pyrula reticulata, Lamarck.
Ringicula ventricosa, J. Sowerby.
Scalaria clathratula, Adams.
Scaphander lignarius, Linneus.
Terebra acuminata, Borson.
Triton heptagonum (?), Brocchi.
Trochus cinerarius, Linneus.
T. millegranus, Philippi.
T. ziziphinus, Linneus.
Turritella planispira, 8S. V. Wood.
Xenophorus sp.
SCAPHOPODA.
Dentalium dentalis (?), Linneus.
BRACHIOPODA.
Terebratula grandis, Blumenbach.
PELECYPODA.
Arca diluvii, Lamarck.
A. lactea, Linneus.
Artemis exoleta, Linneeus.
Astarte basteroti, Lajonkaire.
A. omalit, Lajonkaire.
A. galeotiw, Nyst.
Avicula phalenoides(?),S.V.Wood.
Cardita senilis, Lamarck.
Cardium papillosum, Poli.
Cardium, n.sp.
Cyprina islandica, Linneus.
Cytherea chione, Linneus.
Diplodonta astartea (? ), Nyst.
D. dilatata, 8. V. Wood.
Donax politus, Poli.
Gastrana fragilis, Linneus.
Hinnites cortesyi, Defrance.
TIsocardia cor, Linnseus.
Leda semistriata (?), S. V. Wood.
Lepton deltoidewm, S. V. Wood.
Lima loscombii (?), G. B. Sowerby.
Lutraria elliptica, Lamarck.
Mactra arcuata, J. Sowerby.
Nucula suleata, Bronn.
Ostrea princeps, 8. V. Wood.
Pecten maximus, Linneus.
P. princeps, J. Sowerby.
P. varwes, Linneus.
Pecten, n.sp.
Pectunculus glycimeris, Linneeus.
Pholadidea papyracea, Solander.
Solen ensis, Linneeus.
Tellina benedeni, Nyst.
T. donacina, Linneus.
Thracia pubescens, Pulteney.
T. ventricosa, Philippi.
The Lenham Sandstones of Kent. 265
The next paper of importance was by Mr. F. W. Harmer,! in which
the Lenham Beds were regarded as of older age than the Coralline
Crag, on account of the more southern facies of the fauna, some of
the molluscan species being characteristic of Miocene or Italian
Lower Pliocene, which are unknown or rare in the Coralline Crag.
The author included a distribution table of shells from the Belgian
Diestian beds, showing the Lenham occurrence as well as those
found in the ‘“‘ Box-stones”’ of Suffolk. In the following year the
same author” referred the Lenham Beds to the Older Pliocene under
the new horizonal term of ‘‘ Lenhamian’’, and further recognized
them in a classification table as belonging to the ‘‘ zone of Arca
diluvw”’, and of the age of the Diestian sands.
A more extended scheme of the Pliocene deposits of the East of
England was again published by Mr. Harmer,*? based on _ his
classification table of 1899. In this the Older Pliocene beds were
divided into :—
LENHAM BEDS: Zone of Arca diluvit. Diestian.
Base of Red Crag.
CRS SLO NaS Base of Gain Crag at Sutton. f Waenrode Beds (?).
The Coralline Crag deposits were scheduled as the basement of the
Newer Pliocene series of rocks, which he had formerly placed in
the Older Pliocene.
Mr. W. P. D. Stebbing* next announced the discovery of some
molluscan remains in a patch of sand and ironstone at Netley Heath,
Surrey, between Dorking and Guildford, along the top of the North
Downs, at heights varying from 570 to 600 feet O.D. ‘The specimens,
consisting of sandstone casts, were referred to the genera Cyprina(?),
Modiola, Nassa, Trochus, Cardium, Pectunculus, Tellina, and Thracia,
no specific determinations being given. The author inclined to
the view that these sandy deposits were a westerly extension of
the Lenham Beds near Maidstone, and those at Paddlesworth north
of Folkestone.
Referring to the Lenham fossils, which Mr. E. Van den Broeck *
had examined at the Museum of Practical Geology, that author was
of opinion that they represented a fauna of Diestian age. He noted
the presence of older forms corresponding to the Bolderian (Upper
Miocene) fauna of Belgium, and among the Box-stones at the
Ipswich Museum he identified species found in the Belgium Miocene.
He concluded, therefore, that the Lenham Beds were Diestian, and
_ that the Box-stones corresponded with the Bolderian of Belgium, or
1 ““The Pliocene Deposits of the East of England; the Lenham Beds and
the Coralline Crag’’: Quart. Journ. Geol. Soc., vol. liv, p. 308, 1898.
2 ““On a proposed new Classification of the Pliocene Deposits of the East of
England’’: Rep. Brit. Assoc. (Dover), 1899, p. 752.
° “* The Pliocene Deposits of the East of England, part ii: The Crag of Essex
(Waltonian) and its Relation to that of Suffolk and Norfolk’’: Quart. Journ.
Geol. Soc., vol. lvi, p. 708, 1900.
4 “*Fixeursion to Netley Heath and Newlands Corner’’: Proc. Geol. Assoc.,
vol. xvi, pp. 524-6, 1900.
> “Tie Diestien et les Sables de Lenham, le Miocene démantelé et les Box-
Stones en Angleterre’’: Bull. Soc. Belg. Géol. (Bruxelles) Procés-verbaux,
vol. xvi, pp. 170-3, 1902.
+ ine
‘ Y
266 Notices of Memoirs—R. Bullen Newton—
DISTRIBUTION TABLE OF THE LENHAM MOLLUSCA AND BRACHIOPODA.
GEOLOGICAL HORIZONS.
a) 8/2] | | 2 a a Ol ele 5 = [5] 3
GENERA AND SPECIES, E =/ 8g E 2 ale 2 5 Sl e/8 3 eb z 8 si
|e Plait | an] a] a |e =
a/e]5/8\ 3] s/£/8) 22] 8/2l3/2i lei a/aia |
2|a\5|2/2/a8) 38/5/83) 4/4 2lal|:<)]/ b-<|| 5-6 | >-e |] :< x
Drillia obeliscus, Des Moul., sp. : xe |) 3 x x Xe |) xe || 98
Clavatula jowanneti, Des Moul., sp. . eae K
Terebra acuminata, Borson A : x K xg x x|x
Acteon tornatilis, Linneeus, sp. : x KE xX x I >-4||o-4|| 5-411 9:0] |[ 5 |) xe be |fo-s [9:2 |< xX) x |
PELECYPODA—
Nucula proxima, Say ‘ ; : x || 36/5 Bk xa
Nucula ct. suleata, Bronn 5 ; x alles xi| x x
Yoldia oblongoides, S. V. Wood, sp. . x ba lp-Gi >
The Lenham Sandstones of Kent. 267
\
DISTRIBUTION TABLE—(continued).
GEOLOGICAL HoRrizons.
: a) | to] |
ala 2 |S) 3/8 c S| s)
GENERA AND SPECIES. a E alg q| 3/8 AlS| 4 g| .|8 8) | 3|° ey
rele] S| 8/4) 8) 2/s|2\2|4l slal | al Slsiels
2) 2\ 8) 3|3| 2] 2) 815|8| s| S/S] S| 2/9] el 2) 3
B)E)Sis) Sl ey e(R) 2 3) =) 8) a) eS] s| S| 418
2|alE\a)/S|a)ala|S|e|<|alala\ xe|} dee || 28 [[¢ || 9x] Sell See) Se
Manupecten pesfelis, Linnzeus, sp. x6] 5X K XC || XK
Chlamys princeps, J. de C. Sow., sp. K Ke x K
Himiites crispus, Brocchi, sp. || ox I 3x x K|X|x
Glans senilis, Lamarck, sp. >| oe |) x x x x
Astarte basterott, Lajonkaire Xe %K cs x || Re xK
A. galeottu, Nyst . : : 5 x x R x
A. omalw, Lajonkaire 4 : ‘ x |x x 52) 3x58) xe If x xg) | aR
A. mutabilis, 8. V. Wood 3 : ‘lsxil ilee aK XK R
Cyprina rustica (2), J. Sowerby, sp. . x 3 || | Be x KK |x X
Tsocardia humana (=cor), Linn., sp. x xX x x x He
Dentilucina borealis, Linneeus, sp. Xl 5K || x Exel lisxcel 5X S| || >|) 3x |) HEI) Sq] 9x61) 3x || Sx
Arcopagia ventricosa, Serres, sp. K x XK |)
Tellina benedeni, Nyst & West . x x x x |X| x|x R
Moera donacina, Linneeus, sp. . ° xe x xX xe 90] 2) 34) 31) 3
Gastrana laminosa, J. de C. Sow., sp. K x x x
Spisula arcuata, J. Sowerby, sp... xX mal] I) || 3 X|X|x
S. subtruncata, Da Costa, sp. . ; 3] 58 XE || we] Se) 5 7/31 2<1] <1] ox) 36) 91,55
Pitar rudis, Poli, sp. : : : | ag x Be 5x |) 2] sq) SSI) Be
Callista chione, Linneus, sp. . : || Be x X|xX|X|x|x|x/x|x K
Tapes perovalis, 8. V. Wood . ; K K
Papillicardiwm papillosum, Poli, sp. 2 || 95 |) 9 xl 5 X| xX x
Plagiocardiwm hirsutwin, Bronn xX oe XK || 2x
Hinsis ensis, Linneeus, sp. . XK || 5 xe || 5x |} 3 2 |[ 5 |) 5 |] 32 i) RI) SRI IL wel] Se
Cyrtodaria angusta, Nyst & West, sp. xe] Sel] oe] 5x |) 2x |) 25] 5 |) x
Panopea menardi, Deshayes . : pe XEl] 9] 2 x x x
Barnea cylindrica, J. Sowerby, sp. x x
Aspidopholas rugosa, Brocchi, sp. . Xe x |X
Pholadidea papyracea, Turton, sp. . XK x Pe lax x
Thracia convexa, W. Wood : 4 x x || 5 x x || x| x
T’. pubescens, Pulteney, sp. 3 3 % x x x6 [19:6] 9 56,
BRACHIOPODA—
Terebratula perforata, Desnoy . . x X| |x| x) x) x] x x
268 Notices of Memoirs—The Lenham Sandstones of Kent.
probably a more recent horizon which represented the Mio-Pliocene
or Older Pliocene, a period slightly anterior to the Diestian. He was
also of opinion that the zones of Zerebratula grandis and Isocardia cor
could not be separated, but belonged alike to the Diestian division of
the Pliocenes.
In a further contribution, Mr. Harmer? regarded the Lenham Beds
as synchronous with the ferruginous sandstones of Louvain and Diest.
He stated that among the Diestian sandstone fossils were about sixty
species of Mollusca, some being Crag forms, whereas a few were of an
older or Miocene type and not found in the Coralline Crag; similarly
the Lenham shells included many Miocene species, such as Zerebra
acuminata, Triton heptagonum, Pleurotoma consobrina, P. jouanneti,
Cancellaria contorta, Hinnites cortesyi, and Arca diluvit. A table of
the British Pliocene deposits was included, being nearly similar to
that issued by the same author in 1900, in which the ‘‘ Lenhamian ”
formed the lowest of the Pliocene stages, the Box-stones being
regarded as equivalent to the Waenrode Beds of Belgium (Bolderian,
according to Mr. Van den Broeck).
Subsequently Mr. Harmer? repeated his former views on the age
of the Lenham deposits, the fauna being spoken of as presenting
a distinctly older type than that of the Coralline Crag and approaching
more nearly a Miocene facies, instancing, among other shells, the
abundance of Anadara diluvii, which occurs in the Vienna Basin,
the Touraine area of France, and the Bolderian of Belgium.
In their memoir on the geology of Holland, Messrs. G. A. F. Molen-
graaff and A. J. M. Van Waterschoot Van der Gracht* referred to
the occurrence of Anadara diluvii in the Lenham Beds as indicative of
a Miocene age, the same shell being found in the Miocene deposits of
Peel and Winterswyk in Holland, the rocks of the former place
being stated as the equivalent of the ‘‘ Glimmertons”’ of the north of
Germany or the Tortonian stage of the Miocene, whilst the beds at
Winterswyk were regarded as Middle Miocene. This work also
included lists of molluscan species from the Upper and Middle
Miocene deposits of Holland, many of which are found in the
Lenham Beds.
Another reference to the geological aspect of this subject has been
made by Mr. F. W. Harmer in an ‘Introduction’ to a new work
on British Pliocene Mollusca, where he adheres to his previously
expressed views that the Lenham Beds with the ‘‘ Box-stones” and
the Belgian Diestian deposits should be grouped as Lower Pliocene
and that the Coralline Crag beds of East, Anglia should form the base
of the Upper Pliocenes.
A final notice to make involves a slight alteration in the views of
Mr. C. Reid,® who, in a work recently published, places the Coralline
‘ “4 Sketch of the Later Tertiary History of East Anglia’’: Proce. Geol.
Assoc., vol. xvii, pp. 416-79, 1902.
Bethe Pliocene Deposits of the Eastern Counties of England’’: Geol.
Assoe.., Jubilee Volume, 1908, pp. 86-102.
“ Niederlande ”” : Handb. Region. Geol., vol. i, pt. iii, pp. 51-3, 1913.
‘ The Pliocene Mollusca of Great Britain (Mon. Pal. Soc. ), 1914, pt.i, p. 5.
°C. & E. M. Reid, ‘‘ The Pliocene Floras of the Dutch-Prussian Border’? :
Mededeel. Rijks. Delfst., 1915, No. 6, p. 9.
Notices of Memoirs— Horizon of Dithyrocaris. 269
Crag and Lenham Beds in the Lower Pliocene group, bracketing them
as equivalent to the Diestian—but the ‘‘ Box-stones’’ are scheduled
as Miocene.
(In July will follow Mr. Newton’s conclusions.)
Ii.—Tue Horizon or tHe '‘l'yer-specrmens oF Dr. Scounzr’s
DiITHYROCARIS TRiIcoRNIS aND D. vTestuprInEA. By PxEtTER
Macnatr, F.R.S.E., F.G.S.!
INTRODUCTION.
f{\HE exact locality and as a consequence the precise geological
horizon from which the type-specimens of Dithyrocaris tricornis
and D. testudinea were obtained has long been a matter of considerable
uncertainty. These type-specimens, now preserved in Kelvingrove
Museum, were first described by Dr. John Scouler in the Records of
General Science for the year 18385 (p. 187). The object of this paper
is to demonstrate that these fossils came from what was known as the
Gallowhill Quarries, and that they occupy a position near the top of
the Blackbyre Limestone of this district.
Regarding the beds in which they were found Dr. Scouler says:
‘This limestone is situated about a mile to the east of Paisley, and
was first pointed out to me by Mr. Murray, of the Glasgow Botanic
Gardens. This rock is distinct from and probably reposes on the true
Carboniferous Limestone, but as only a small patch of it is exposed,
the greater part being covered by the soil, it was impossible to
trace its relations with the subjacent strata. This limestone is of an
extremely compact nature, with little plates of calcareous spar
disseminated through its substance. It readily splits into flags of
variable thickness, which are sometimes made of a multitude of
extremely thin layers, indicating that the whole stratum has been
formed by the gradual and tranquil deposition of transported matters.
The organic matters differ widely from those which we observe in the
Carboniferous Limestone. I could detect no Productide nor any
fragments of corals or stems of crinoid animals, nor, in short, any
decidedly massive production. Instead of these, on splitting up the
rock we observe impression of ferns of great variety and beauty, the
remains of entomostraca, which are of gigantic size when compared
with the analogous species which still abound in our lakes and pools.
Two species belonging to a new genus were obtained, and the
numbers might have been greatly increased had not the hardness of
the rock rendered the extraction of the specimens a difficult task.”’
It will be noted that though in the above account no definite locality
is mentioned, yet they are recorded as coming from a locality about
a mile to the east of Paisley. Another important feature of this
account is that it is such an exact description of the nature of the
limestone in which the fossils occur that we can have no hesitation in
identifying it with the bed to be described subsequently in this
paper.
* Reprinted in a slightly abridged form from the Transactions of the
Geological Society of Glasgow, vol. xvi, pt. i, 1915-17.
270 Notices of Memovrs—P. Macnair—
In the New Statistical Account of Scotland, published in 1845,.
under the section ‘‘Town and Parishes of Paisley”, we find the
following important reference to this limestone and these fossils
(1845, p. 157). It is of very great interest, because it appears to
have hitherto escaped notice, and because it cites the Farm of
Gallowhill as the exact locality where the fossils were obtained.
The reference runs as follows: ‘‘To the north-east of Paisley, on
the Farm of Gallowhill, a quarry has of late been wrought in an
extensive bed of schistose rock lying almost horizontally about 3 feet
below the surface. Its colour is dark grey approachiug to black.
ts texture is compact and fine grained, and it readily splits into
layers, but is with difficulty broken across. The fracture is splintery
and rather conchoidal. It is composed of about 32 per cent. of
carbonate of lime, 47 of sand, and 9 of alumina. This rock abounds
in beautiful specimens of many genera and species of ferns, as also of
shells, chiefly Terebratula, Nucula, and Orthoceratites. The layer of
till immediately above this rock for several inches closely resembles
Fuller’s earth.” The most interesting point, however, bearing upon
the locality from which Scouler obtained his fossils 1s contained in
the following footnote, which is added: ‘‘'T'wo species found here
belonging to a rare genus are described by Dr. Scouler in Thomson’s
Records of General Science, vol. 1.”
In 1865 Mr. James Armstrong (1865, p. 74) states in a paper
published in the Zransactions of this Society that specimens of
Dithyrocaris were obtained by Dr. Scouler upwards of thirty years
ago in a limestone excavated for the foundations of the Paisley
Barracks.
In a paper read to the Society in 1893 Mr. James Neilson (1893,
p. 71) makes the following statement regarding the locality where
ae type-specimens of Dithyrocaris tricornis and D. testudinea were
found: ‘It is worthy of notice that when the late Dr. Scouler first
discovered Dithyrocaris at Inkerman, near Paisley, nearly the entire
animal was got. These beds were afterwards lost, and during many
years since, the finding of only one or two carapaces has been
recorded.”” From this it will be seen that Mr. Neilson, in utter
disregard of any of the foregoing statements as to the locality at
which the specimens were got, has shifted it to Inkerman, 14 miles
west of Paisley. But he gives us no reason for his doing so, and
T am utterly unable to understand upon what grounds it was made.
In their memoir on the British Paleozoic Phyllocaride Professor
T. Rupert Jonesand Dr. Henry Woodward (1898, p. 147) still further
complicate the matter, for in the text they say that Dr. Scouler’s
original specimen of Dithyrocaris testudinea is in hard, black, earthy
limestone from the Carboniferous Limestone Series about a mile to
the east of Paisley, the latter part of the sentence being quoted from
Dr. Scouler’s paper. But in a footnote they say, ‘‘ At a place now
ealled Inkerman, where Mr. R. Dunlop has lately most obligingly
sought for further indications of these fossils, but without success.”
In this footnote they have evidently been misled by Mr. Neilson.
As we have already said, we hope to show that the statement made
by the authors of the Statzstical Account is probably the correct one,
Horizon of Dr. Scouler’s Dithyrocaris. PATA
and that the specimens were got in a peculiar limestone which was
formerly quarried on Gallowhill Farm, 14 miles to the north-east of
Paisley, and that both Mr. Armstrong’s and Mr. Neilson’s statements
as to the locality where they were found are erroneous.
Tue TYypr-sPECcIMENS OF DITHYROCARIS TRICORNIS AND D. TESTUDINEA.
The type-specimens of the two species of Duithyrocaris were
sh originally presented to the Anderson College Museum by Dr. Scouler,
‘4 and some years ago were gifted, along with other specimens, to
; Kelvingrove Museum by the Governors of the Royal Technical
College. D. tricornis shows the two valves of the carapace lying
he’ in an almost symmetrical position, but reversed so that the anterior
_ part is approximately in the position that the posterior part ought to
: be, a phenomenon not unusual in decaying and floating Phyllopods.
Oe SRE eee ios WM
GS RGSS SNS. a N\
NANOS RAN SS \ \Y \\
CSS SS Vy W
— Som“ MQ y W i »
Wo? SN Rou BN )
C SAW
NESS a
RAY
RE LQ
=
SSS
Fig. 1.—A. Dithyrocaris tricornis, Scouler. B. D. testudinea, Scouler.
From the original drawings in Scouler’s paper. The type-specimens are
now in Kelvingrove Museum.
The three somewhat obscure abdominal segments and a tail with
three spines project from the lower part of the front of the carapace.
The gastric teeth are exposed through the test.
In Dithyrocaris testudinea the broad oval carapace is semi-elliptical
in shape. The two valves lie in opposition by their dorsal edges,
and overlap irregularly towards the lower half of the dorsal region.
In both valves the central border is seen to terminate in a smail
obscure spine. A strong ridge showing the characteristic rugose
structure of the overlapping chevron-shaped scales runs down the
272 Notices of Memoirs—P. Macnair—
middle of each valve. The abdominal segments which project from
behind the carapace have been considerably crushed. The tkree
caudal spines are well shown. They are of nearly equal length,
stout, fluted, and show traces of granulation on the riblets. Fig. 1,
which shows Dithyrocarts tricornis and D. testudinea, is after the
original drawing in Dr, Scouler’s paper.
The only other fossil preserved on the slabs containing the type-
specimens is a single specimen of Lingula mytiloides, which is seen
on the large slab with Dithyrocaris tricornis. As we shall presently
see, this is the commonest of all the fossils found in the Gallowhill
Limestone, i in which it is often exceedingly numerous.
Tue Gattownitt Limestone.!
About two years ago my attention was first directed to the peculiar
character of the limestone that forms the wall to the east of Gallow-
hill, near Paisley. The locality from which Scouler’s type fossils
had been obtained had for a long time exercised my mind, as it had
done that of other local geologists, and when I first saw the limestone
of which the wall is built I was at once struck with its strong
similarity to that forming the matrix of the Scouler fossils. I took
a specimen of the limestone with me, and a comparison of it with
the specimens in the museum at once confirmed their identity. Both
present the same earthy-like appearance, their joint faces being lined
with calcite, and strongly charged with iron pyrites in nodular
masses and in strings and isolated cubes. Associated with the lime-
stone are bands of a much more argillaceous and sandy nature, of
which examples may be seen in the dykes and bings, the large
bing to the south of Gallowhill House having yielded numerous
examples of the different types of sedimentation that appear to have
prevailed upon this horizon. Iam indebted to Mr. R. 8S. Houston
for the following analysis of the limestone, which, like the analysis
given in the Statistical Account, shows that it contains a large per-
centage of siliceous and clayey matter :—
Carbonate of lime . ; é : 48-67
Carbonate of magnesia . : : : -98
Carbonate of iron . é ; ; i 5:70
Alumina A 3 : x 1-02
Siliceous matter (clay) : 4 5 : 40-23
Carbonaceous matter ‘ : 5; 3 _ 2-30
Moisture : : ; : 5 t “57
99-47
After convincing myself of the lithological identity of the two
limestones I began to search for some evidence of a Phyllopod fauna,
and was soon rewarded by clear evidence of its presence. Nothing
to equal Scouler’s specimens has yet been found, but fragments of
carapaces and tail spines are sufficiently numerous and in a similar
state of preservation to conclusively demonstrate the identity of the
1 Tt should be clearly understood that the local term ‘‘ Gallowhill Limestone”’
used throughout this paper does not stand for any new limestone horizon, but
is only used to express a peculiar phase occurring at the top of the Blackbyre
Limestone. This, indeed, is the main object of the paper.
Horizon of Dr. Scouler’s Dithyrocaris. 273
Gallowhill Limestone with that which forms the matrix in which
Scouler’s fossils are preserved. The most abundant fossil in the
Gallowhill Limestone is Lingula mytiloides, many of the slabs being
simply crowded with them. ‘The full significance of the faunal
association found in the Gallowhill Limestone will, however, be
discussed in more detail presently. In his paper Scouler refers to
the absence of Productide, corals or stems of crinoid animals, but
Productus longispinus and Rhynchonella pleurodon are fairly abundant
on some slabs. Slabs of the limestone rich in erinoidal remains
have also been observed. But whether these represent the same bed
as that which carries the Phyllopod fauna or one on a slightly
different horizon we have not yet been able to determine definitely,
but we are inclined to favour the latter view.
ARKLEstoN Curtine AND Former Exposures aT GALLOWHILL.
In my paper on the Hurlet sequence in North Ayrshire I have
given an account of the strata exposed in the Arkleston Cutting,
and it is there shown that the top limestone is the Hurlet Limestone,
here 3 to 4 feet thick and dipping towards the east. Below it comes
the Hurlet Alum Shale, only some 6 inches thick, followed by. the
Hurlet Coal, originally from 5 to 6 feet thick. The coal has been
split up the centre by a sill of dolerite, some 80 feet in thickness,
lenticles of the coal occurring within the sill. Below the sill comes
some 18 feet of shale and fireclay, in which there is a limestone in
three seams full of entomostraca and fish remains, and which is
clearly the equivalent of the Baldernock Limestone of the Campsie
district. The whole group of sedimentary strata is much pyritized
and altered by contact with the intrusive sill of dolerite. A search
for the alum shale fauna in the fragments that are seen to lie above
the sill has not as yet been successful in yielding any examples of
that characteristic fauna, as the shale is very completely baked.
But the discovery of the fauna at this point is not yet regarded as
entirely hopeless. I have also shown in the paper mentioned that
a highly fossiliferous limestone was at one time exposed between
the bridge and the signal box, and that, dipping towards the east,
it passed beneath the strata in the cutting just described. A con-
sideration of all the available paleontological and stratigraphical
evidence goes to show that this limestone must have been the
equivalent of the Blackbyre Limestone.
If we turn to the 6-inch-to-the-mile Geological Survey map, of
which Fig. 2 is in part a reproduction, it will be noticed that the
limestone, there shown as trending northwards towards the Arkleston
Print Works, and then bifurcating into two outcrops towards the
north-west, clearly lies below the sill now seen in the cutting. When
the Geological Survey map was made in the year 1875 the railway
ran through a tunnel at this point, and the Hurlet Limestone lying
above the sill does not appear to have been exposed. If it was it is
not indicated on the map. ‘The limestone represented on the map is
drawn as two narrow outcrops at the Paisley end of the tunnel.
Unfortunately no exposure can now be observed between the bridge
over the railway and the signal box. But that a limestone was at
DECADE VI.—VOL. IV.—NO. VI. 18
s \
Notices of Memoirs—P. Macnair—
-- fei
Fic. 2.—Sketch-map and section along the railway at Arkleston, Paisley.
a, Blackbyre Limestone with Gallowhill Limestone phase at top;
6, Cementstone with rootlets; c, Entomostracan Limestone; d, shales
and fireclay ; ¢, dolerite sill; f, Hurlet coal; g, alum shale; hk, Hurlet
Limestone.
Horizon of Dr, Scouler’s Dithyrocaris. 21D
one time exposed at this point is made clear both by the Survey
map and by Mr. Blair’s paper published in our Transactions (1889,
p- 183). In this paper Mr. Blair describes it as exhibiting ‘‘a wider
variety and more abundant quantity of delicate organisms than I have
yet seen in any of these deposits”.
The section between the railway bridge and the signal box at the
Paisley end of the cutting is now so completely grassed over that not
a vestige of rock can now be seen, and weare left to judge by analogy
with the general sequence of the district what the horizon of the
limestone formerly exposed at this point may be. Fortunately,
though exposures are extremely rare upon this horizon in this
district, yet the cumulative evidence is such as to leave no room for
any doubt in our minds that the limestone formerly exposed at this
point, known locally as the Gallowhill Limestone, must be the
equivalent of the Blackbyre Limestone of the Hurlet type section.
On the east side of the railway bridge the lowest bed seen in the
railway cutting is a band of grey cement limestone with rootlets,
which all over this area is a well-marked horizon lying immediately
below the Hurlet Coal and above the Biackbyre Limestone. It can
be seen at Crookston Farm cropping from below the dolerite sill in
exactly the same fashion as it does in this cutting, but there in
addition to the rootlets it contains fish teeth, Sprrorbis, and
entomostraca.
Below this rooty cementstone there comes in the Hurlet district
a variable thickness of shales succeeded by the Blackbyre Limestone.
This view has been expressed in the section in Fig. 2; a@ is the
Gallowhill Limestone, being the top of the Blackbyre Limestone,
shown as folded into a gentle arch, which gives off in its eastern
limb, 4 the cement limestone with rootlets, ¢ thin bands of lime-
stone with entomostraca and fish remains, @ beds of shale and
fireclay, ¢ intrusive sill of dolerite, f and g Hurlet Coal and alum
shale, and # Hurlet Limestone.
As has already been stated, no exposures of the Gallowhill Lime-
stone can now be seen at any of the localities where it was formerly
worked. But the position of two of the quarries south of the
Arkleston Print Works can still be seen. Another quarry appears to
have been opened a little to the south of Gallowhill, opposite the
Mote Hill. The positions of these quarries are indicated on the map,
and they seem to have been somewhat extensively worked about the
year 1835, when Scouler’s fossils were found, the old Powder
Magazine between Arkleston and South Arkleston haying been built
of it, as well as a large number of the dykes in the Gallowhill
Policies. It was also used in some walls in the neighbourhood of the
Paisley Barracks, where it can still be seen. ‘his may have some-
thing to do with Armstrong’s statement that Scouler’s fossils were
found in a limestone excavated for the foundations of the Paisley
Barracks.’ That the Gallowhill Limestone must extend considerably
! Since writing this paper I have been informed by Mr. R. Houston that in
making the foundations for the villas adjoining the Paisley Barracks it was
found that slabs of the Gallowhill Limestone had been used to fill up old
hollows in the surface of the ground.
276 Notices of Memoirs—P. Macnair—
to the west of the outcrop, as drawn on the map, is made clear both
from the evidence derived from the old quarry opposite the Mote Hill
and also from recent information that we have obtained which shows
that Gallowhill House rests upon it. But whether it is continuous
over this area or is repeated by faulting we have no data to decide,
and the position of the outcrop is left much as it is given in the
6-inch-to-the-mile Geological Survey map.
The statement in the Statistical Account that the layer of till
immediately above the Gallowhill Limestone for several inches closely
resembles fuller’s earth is of great interest, as we seem to recognize
in this the peculiar ashy fireclay which is generally found to rest on
the eroded top of the Blackbyre Limestone of Renfrewshire and
North Ayrshire.
In interpreting the structure of the ground between Arkleston and
the Cart it seems to us that there must be a low arch bringing in the
strata that lie immediately below the Hurlet Limestone. On the east
this arch sinks below the Hurlet Limestone, as exposed in the
Arkleston Cutting, and on the west it must pass below the outcrop
of the Hurlet Limestone and Coal which has been drawn by the
Survey to cross the White Cart Water near Carlisle Quay and
Nethercommon. An exposure of limestone underlaid by a bed of
coal with pyrites can at present be seen at low tide immediately
below the Swing Bridge at Carlisle Quay, but owing to the limited
nature of the exposure it is at present difficult to determine whether
this is the Hurlet Limestone or the Blackbyre Limestone, but it is
certainly the equivalent of one of these.
Bores put down along the outcrop of the dolerite on the Gallowhill
Policies show that the dolerite rests along this line upon a series of
thick-bedded shales, fireclays, and sandstones which have been bored
into for a depth of more than 30 fathoms. There can scarcely be any
doubt that the uppermost of these represent the sediments which le
between the Blackbyre Limestone above and the Hollybush Lime-
stone below. On the 6-inch-to-the-mile Geological Survey map
a bore put down to the south of Gallowhill shows the presence of
a coarse limestone 1 ft. 7 in. thick at a depth of 12 fathoms. This is
probably upon the position of the Hollybush Limestone.
ComMPARISON WITH THE BLACKBYRE LIMESTONE AT OTHER LOCALITIES.
From the evidence that has been adduced there can be no doubt
that the Gallowhill Limestone must lie somewhere on the horizon of
the Blackbyre Limestone, and we now pass to consider the evidence
that exists bearing upon the lithological and paleontological charac-
teristics of the Blackbyre Limestone in this district. At the type
locality (Blackbyre Farm) the Blackbyre Limestone consists of two
parts, a lower full of small Brachiopods, largely Productus longispinus,
and an upper part which is crinoidal. Neither of these, however,
can be compared with the Gallowhill Limestone. As a rule, the
Blackbyre Limestone of this district may be described as essentially
a Brachiopod or shelly limestone with occasional bands of Lztho-
strotion. The contention of this paper is that the Gallowhill
Horizon of Dr. Scouler’s Dithyrocaris. 277.
Limestone is simply a phase characteristic of the top of the Blackbyre
Limestone, and as the top of the limestone is not seen at the type
locality it is quite possible that it may be present though not exposed.
The section exposed at Jenny’s Well, a quarter of a mile to the
east of Blackhall, Paisley, is practically a counterpart of that seen in
the Arkleston Cutting, and the additional corroborative evidence
bearing upon the relationship of the Gallowhill Limestone to the
Blackbyre Limestone is so complete that it requires to be examined
in some detail. The section shows a fairly continuous sequence from
the Blackhall Limestone down to the base of the sill of dolerite which
here occupies exactly the same stratigraphical position as in the
Arkleston Cutting, having the Hurlet Limestone above and the
Blackbyre Limestone below.
Unfortunately the outcrop of the Blackbyre Limestone cannot be
seen, but its position is shown by a hollow immediately to the west
of the dolerite sill, which runs in a north and south direction from
the Cart up the side of Dykebar Hill, marking the line along which
it was formerly quarried. Just at the point where the road crosses
the railway the Blackbyre Limestone was exposed during the making
of the line. It cannot now be seen, but the walls on each side of the
railway at this point are built of it, and the blocks of limestone show
all the features of the Gallowhill Limestone on the one hand and of
the Blackbyre Limestone of the type section on the other.’
An examination of the exposure of the Blackbyre Limestone seen
in the bed of the Levern at Neilston, a little above the point where
it crosses the main road to Lugton, helps, we think, to throw some
light upon the relationship of the Gallowhill Limestone to the
Blackbyre Limestone. The section here is somewhat obscure, but
the main mass of the limestone is rich in corals and Productide. The
former are represented by bands of Lthostrotion and solitary corals,
the latter by various species of Productus and by numerous specimens
of the large variety of Productus giganteus. On the top of the main
- mass of the limestone rests a bed of fine-grained cementstone, which
presents all the features of the Gallowhill Limestone. Traced into
North Ayrshire, it forms the peculiar fine-grained top of the Dockra
Limestone and its equivalents, which we have elsewhere shown to be
the same as the Blackbyre Limestone of the Hurlet section.
An examination of the sections exposed in the burn at Meikle
Corseford, and on the Gryffe Water below Bridge of Weir, also
affords certain evidence which goes to confirm the relationship of the
Gallowhill Limestone to the Blackbyre Limestone. At both localities
the Blackbyre Limestone is capped by a fine-grained crinoidal lime-
stone comparable to the crinoidal phase of the Gallowhill Limestone.
And at both these localities it is overlaid by the peculiar green ashy
mud which is probably identical with the so-called fuller’s earth
found in the Gallowhill Quarry.
1 The evidence derived from these blocks shows that the Blackbyre Lime-
stone of this locality has a strong resemblance to that exposed in the Beith
Quarries. It carries a varied Brachiopod fauna and contains thick bands of
LInthostrotion and other corals.
278 Notices of Memoirs—Horizon of Dithyrocaris.
Tue FaunaL AssoctatioN oF THE GALLOWHILL LIMESTONE.
Thefauna of the Gallowhill Limestone 1s an exceedingly characteristic
one, and has a remarkable resemblance to that which exists ona much
higher stratigraphical horizon, the Calderwood Cementstone of the East
Kilbride district. So striking is the similarity between the two that
we here institute a comparison between them to show that they must
have been accumulated under closely similar physical conditions.
Both in the Calderwood Cementstone and the Gallowhill Limestone
the fossils are but sparingly distributed throughout the limestone,
and the rarer forms only occur at wide intervals. ‘he following list
gives some of the principal species that occur in the Calderwood
Cementstone at such localities as Burnbrae, Jackton Burn, Kirkton-
holm, Glebe Quarry, and Limekilns House.
Serpulttes carbonarius, M‘Coy. Lingula squamiformis, Phill.
S. membranaceus, M‘Coy. Productus senireticulatus, Mart.
Spirorbis caperatus, M‘Coy. P. longispinus, Sow.
Dithyrocaris glabra, Woodw. & Eth. Rhynchonella plewrodon, Phill.
D. granulata, Woodw. & Eth. Streptorhynchus crenistria, Phill.
D. ovalis, Woodw. & Eth. Aviculopecten knockonniensis, M‘Coy.
D. testudimea, Scouler. Posidonomya corrugata, Eth.
D. tricornis, Scouler. ' Nuculana attenuata, Flem.
Palemysis, Peach. Protoschizodus equilateralis, M‘Coy.
Palecrangon, Salter. Nucula gibbosa, Flem.
Palesquilla Pattoni, Peach. Sanguinolites plicatus, Portl.
Anthrapalemon Coutsw, Peach. Orthoceras attenwatum, Flem.
Disema nitida, Phill. Nautilus sp.
Serpulites carbonarius occurs in the Calderwood Cementstone, some
slabs being simply covered with the tubes of this worm. In the
Gallowhill Limestone they occur in exactly similar conditions. Ihave
also found traces of Serpulites membranaceus and Spirorbis caperatus in
the Gallowhill Limestone.
_ The Phyllopod Crustacea from the Gallowhill Limestone include,
besides the two species Dithyrocaris tricornis and D. testudinea, others
whose specific characteristics have not yet been determined. Their
mode of occurrence and state of preservation are strongly suggestive
of the conditions under which these fossils appear in the Calderwood
Cementstone. No traces of the Schizopods which occur in the
Calderwood Cementstone have as yet been found in the Gallowhill
Limestone, but further search may yet reveal the presence of some of
these most interesting forms.
The Brachiopod fauna of the Gallowhill Limestone is strikingly
similar to that of the Calderwood Cementstone. In the Carluke
district the Calderwood Cementstone is known as the Lingula Lime-
stone, because of the large numbers of that fossil which occur in it.
In the Gallowhill Limestone Zingula squamiformis is replaced by
Lingula mytilocdes, which, as has already been pointed out, occurs in
great numbers. The more common Brachiopods in the Gallowhill
Limestone are Productus longispinus, P. semireticulatus, and
Rhynchonella pleurodon, and less commonly WDiseina nitida and
Streptorhynchus crenistria.
Lamellibranchs are exceedingly scarce in the upper part or estuarine
phase of the Gallowhill Limestone, but several specimens referable
eK } 4 i
Reviews—Prof. Chamberlin—The Origin of the Earth. 279
to Sanguinolites plicatus have been found, and one specimen closely
resembling Protoschizodus equilateralis and Posidonomya corrugata
also occurs, and from the lower and more crinoidal parts Nuculana
attenuata and Nucula gibbosa have been obtained.
The Cephalopoda are represented in the upper or estuarine part of
the limestone by Orthoceras attenuatum and by a Nautilus which has
not been specifically determined.
Fish remains, in the shape of scales, spines, and plates, occur in
the upper part of the limestone, though in a somewhat fragmentary
condition. They are clearly referable to those ganoids which are
found in the estuarine facies of the Carboniferous formation.
Plant remains are fairly common, principally the fronds of ferns,
and occurring as they do in association with the Phyllopods and
with Productus longispinus and other Brachiopods they tend to
aecentuate the resemblance between the Gallowhill Limestone and
the Calderwood Cementstone.
From what has been said it will be seen that the whole assemblage
of plants and animals found in the Gallowhill Limestone is strikingly
similar to that which occurs in the Calderwood Cementstone. That
these strata are of estuarine origin is made clear by the manner in
which the remains of land plants and animals are intermingled with
those of estuarine and marine types, just as we find in estuarine
deposits at the present day.
I have to acknowledge my indebtedness for much assistance in
working out the details of the Gallowhill district to Mr, William
Holmes, of Sandyford.
REFERENCES.
ARMSTRONG (A.). 1865. ‘‘ Note on the Discovery of the Teeth of Dithyro-
carts?’ + Trans. Geol. Soc. Glas., vol. ii, p. 74.
BLAIR (M.). -1889. ‘‘The Surface Geology of Paisley’’: Trans. Geol. Soc.
Glas., vol. ix, p. 139.
BuRNS & Macnair (R.). 1845. New Statistical Account of Scotland—
Town and Parishes of Paisley, p. 157.
- Jones (T. Rupert) & Woopwarp (H.). 1898. A Monograph of British
Carboniferous Phyllopoda, p. 147.
NEILSON (J.). 1893. ‘‘On the Calderwood Limestone and Cement Stone,
with their Associated Shales’’: Trans. Geol. Soc. Glas., vol. x, p. 71.
SCOULER (J.). 1835. ‘‘ Description of two species of Argas (Dithyrocaris) ”’ :
Records of General Science, vol. i, p. 137.
WoopwarpD (Henry). 1865. ‘‘ Crustacean Teeth from the Carboniferous and
Upper Ludlow of Scotland ’’: Grou. Mac., pp. 401-4, Pl. XI.
—— 1874. ‘‘ Dithyrocaris from Kilbride’? : GEOL. MAG., p. 107.
WooDwWarD (Henry) & ETHERIDGE (Robert), jun. 1873. ‘‘ Dithyrocaris from
Carboniferous Limestone ’’: Grou. MAG., p. 482.
REVIEWS.
I.—Tue Oricin oF THE EartH. By T. C. Cuamperiin. 8vo;
pp. xi, 271. University of Chicago Press. 1916.
HIS book might appropriately have asa sub-title ‘‘ The Intellectual
Autobiography of a Geological Cosmographer and his Reflections
on the Genesis and Geographical Evolution of the Karth”. The
author has collected into a small monograph the results of his
studies of the origin of the earth, and the further development of
280 Reviews—Professor T. C. Chamberlin—
his well-known planetesimal theory. The author tells us of the
development of his interest in cosmography, and shows us the gradual
growth of his present conclusions. He was first led into what he
calls the ‘‘ cosmographic fens and fogs” by his desire to reconcile
the existence of former glacial periods with faith in an originally
molten globe. He, therefore, with the aid of various mathematical
friends, notably Professor Moulton, inquired whether the earth could
have been in the condition of incandescent gas; and he was forced to
abandon Laplace’s nebular hypothesis. In the first series of chapters
he points out the objections to it; he claims that it is inconsistent
with the kinetie theory of gases, and that if the temperature were
high enough to keep the very refractory constituents of the earth in
a gaseous state they could not have been held together by gravity.
He further holds that if the solar system had originated from a con-
tracting nebula the equatorial velocity of the sun should be 270 miles
per second, whereas it is only 14 miles per second. In reference to
the support given to the nebular theory by the practical agreement
of the average inclination of all the planets and planetoids to the
plane of the solar equator with the requirement that they should
revolve in that plane, he objects that the divergence of 5° is greater
than should occur. A weightier objection is that though the sun is
744 times as great as all the planets together, yet they, +35 of the
mass, own 98 percent ef the momentum. The criticisms of Laplace’s
theory are undeniably very weighty. Professor Chamberlin admits
its attractiveness, and remarks (pp. 61—2) that its long acceptance
was the natural result ‘‘of its unsurpassed simplicity and beauty,
and of the great service it has rendered the progress of thought”’,
and of the ‘‘long list of general harmonies between the salient
features of the solar system and the broader terms of the hypothesis.
On such general harmonies the hypothesis was founded, and from
these it gathered to itself a wide adherence’’.
The older forms of the meteoritic theory Professor Chamberlin
also regards as unsatisfactory. He insists that Sir George Darwin’s
well-known demonstration that a swarm of small meteorites would
behave physically as a gas in which each meteorite would act as
a molecule rests on the doubtful assumption that the separate
meteorites should have an elastic recoil like molecules. Professor
Chamberlin’s presentation of his own hypothesis is not free from
serious difficulties, and is perhaps less attractive than in its original
form. ‘he planetesimals now play a comparatively small part.
Professor Chamberlin regards the meteorites as fragments of an old
world rather than as the germs of a new. He derives the solar
systems from spiral nebule; and he attributes the latter to the
scattering of the material of compact stars by that process of dynamic
disruption the possibility of which was indicated by Roche. If two
bodies approach one another their mutual attraction produces an
internal tide that may break the surface and lead to the escape of
a large mass of material through asolar prominence. The matter thus
drawn upward may fall back to the parent body as a colossal deposit
of volcanic agglomerate; or it may be raised so high as to remain
suspended between the two bodies and revolve around the parent as
The Origin of the Earth. 281
a planet; or it may be captured by the attracting star and become
its planet; or finally it may be shot off into space and escape from
the influence of both bodies and give rise to a comet or swarm of
meteorites. The tide may cause projections at opposite sides of the
parent star, and the matter shot out may, it is held, remain connected
to the parent by a nebular band, and thus give rise to a spiral
nebula with the usual two arms. Professor Chamberlin suggests
that the detached nebulous mass of the nebula M51 in the con-
stellation of the Hunting Dogs was due to a mass which was torn
from the main nebula by the disruptive approach of another star and
was left connected to it by a nebulous band.
According to Professor Chamberlin’s theory, as the spiral nebule
are due to the dynamic disruption of a compact and possibly cold
star, they do not represent the original condition of matter. They
are apparently an ephemeral stage in the life-history of solar systems.
The genesis of such systems is therefore pre-nebular. If nebule are
due either to direct collision or dynamic disruption their life should
be comparatively short. The stars which blaze up in consequence of
hypothetical collisions lose their sudden brilliancy in a few weeks or
months; and if the light of the nebule is due to incandescence it ought
soon to wane. The author has clearly shown the fundamental diffi-
culties in Laplace’s theory; but the nebule remain one of the most
perplexing enigmas of the heavens. Indeed, several features in the
solar system, such as the uniform direction of rotation of the vast
majority of its members, in regard to the reasonable explanations
that have been offered for the insignificant exceptions, agree better
with the requirements of Laplace’s theory than with that of the
formation of nebule by Roche’s dynamic disruption.
The second part of the book deals with the less speculative problems
of geographical evolution, and it is interesting to note that the author,
approaching the subject by his special route, lays much stress on the
arrangement of the continents and the oceans as six interlocking
triangles arranged around the Equator, on the antipodal position of
land and water, and on the periodic variations of the major geographical
processes in consequence of the deformation of the earth’s crust.
These views have been advocated in connexion with the tetrahedral
hypcethesis, to which the author does not refer. The conclusion in
this part of the work to which many geologists are most likely to
dissent is the adoption of the permanence of oceans and continents in
an extreme form. ‘The author attributes the position of the major
elevations and depressions on the earth’s crust to influences which
acted upon it during its primary consolidation. Lord Kelvin adopted
that conclusion and attributed the continents to segregations in the
earth while it was still gaseous. Professor Chamberlin suggests they
may be due to certain parts of the earth’s surface haying been cooled
by descending currents of air in the anticyclones of the earth’s
primitive atmosphere.
The book deserves attention by all geologists interested in the
early history of the earth, and can be read with interest by any
student of either geology or geography. It gives comparatively few
references; but those given are of special use to geologists by
pol sh cinta)
uw
=
282 Reviews—The Dunstones of Plymouth.
directing attention to astronomical and dynamical memoirs which
they may easily overlook. The fewness of references is part of the
method of the book. Its attractiveness is largely due to the personal
element in it, which shows the mental processes by which the author
felt his way from the problems of glacial climates to his illuminating
contributions to the pre-geological history of the earth. W.G
II.—Tue Dowsronrs or PiymourH anp THE Compron-ErrorD Griv.
By R. H. Worrn, M.Inst.C.E., F.G.8. Transactions of the
Devonshire Association for the Advancement of Science, Litera-
ture, and Art, xlvili, pp. 217-59, 1916.
N this paper the author sets forth some very revolutionary views
regarding the Devonian igneous rocks of the Plymouth district.
These rocks (‘‘the Dunstones’’) are described by Mr. Ussher and
Dr. Flett in the Geological Survey memoir of the Plymouth and
Liskeard district as pillow lavas (spilites), diabases, and schalstein
tuffs. The present author, however, comes to the conclusion that
the rocks which he classes together under the old name of dunstones
are all intrusive, there being no extrusive lava in the series which he
has examined. The pillow structure which they exhibit is attributed
to the rolling of parts of the walls of the fissure into the dunstone as
it was intruded, since the pillows are generally attached to the main
mass of the dyke and are surrounded by a skin of baked slate. The
associated cherts, previously described as radiolarian cherts, are
regarded as silicified slates, as they only extend over a space of the
same extent as the dykes and are often included in the dyke or inter-
bedded with thin layers of dunstone. There are three kinds of
metamorphism associated with the intrusion of the dunstones,
silicification, chloritization, and dolomitization, which with the
baking, affect the surrounding slates, either together or separately
in different places. ‘The schalstein tuffs and breccias of the Survey
memoir are described as being composite rocks of slate and dunstone,
produced by the brecciation of the sides of the fissure, accompanied by
the mixture of the slate fragments with the igneous rock. The
dunstones are therefore regarded as having been intruded into the
slates after they had developed a slaty cleavage. The Compton,
Crabtree, and Wearde grits, which have been described as voleanic
grits contemporaneous with the pillow lavas, are regarded as ordinary
sediments, produced by the weathering of pre-existing igneous rocks,
the evidence being drawn both from the mineral characters of the
erits themselves and from the variety of the pebbles in the pebble
bed associated with the grit and dunstone at Crabtree.
W. H. Wricocgson.
I1I.—A Sywopsts oF AMERICAN EARLY ‘TERTIARY CHEILOSTOME
Bryozoa. By Frrpryanp Canu and Ray 8..Basster. United
States Museum Bulletin 96. pp. 88,6pls. Smithsonian Institu-
tion. Washington, 1917.
S one of the authors explains in his preface, the volume is
a foretaste of a larger monograph on Tertiary Polyzoa; and,
certainly, this hors d’ceuvre whets the appetite for what is coming.
Brief Notices. 288
It consists of (1) a short statement of the principles of classification ;
(2) a systematic synopsis containing diagnoses both of the divisions
of higher rank than generic, and of all new genera and species; and
(8) figures of the new species.
To the general reader by far the most interesting section is the
two pages devoted to the principles of classification; though the
actual systematic scheme carries much that is of interest to the worker
of Polyzoa, particularly to the specialist of Tertiary forms. And it is
satisfactory to note, in this connection, that the fundamental divisions
of the Cheilostomata adopted by Levinsen have been accepted here.
The plates, too, call for congratulation, being, apparently, photo-
graphic reproductions of the originals, and, as such, are comparable
with the excellent microphotographs of Cretaceous Polyzoa ptblished
by Brydone in the GrorocrcaL Macazine.
It is a pity that, with the need of establishing many new genera,
more accuracy was not obtained in putting together the names.
Here, especially indeed, the reviewer, having experienced the
difficulties involved, would temper his criticism with sympathy.
If the Latin ending -ella be permitted to Greek stems, the names
Ottonella, Dacryonella, Aechmella and others are both pleasant to
hear and easy to pronounce; but not so Stomachetosella, which is also
incorrectly formed, as are Stamenocella and Trematoichos. But Metro-
pertella is impossible, for zep/ is followed by nothing but a diminutive
ending. Metracolposa and Schizaropsis would be more correct if, in
the former, the first @ were o and the final @ dropped, and, in the
latter, the second syllable omitted. Velumedla, though sounding well,
is an impossible form (Velel/a is, of course, preoccupied). What
Lewis Carroll would have called the ‘portmanteau’ words
Membrendecium for ‘‘Membranipora with endozocecial avicularia’’,
Cribrendecium for ‘‘Cribrilina with endozocecial ovicells’’, Schizemiella
—‘‘, PP. 15-17.
**On the Successive Stages of Slaty Cleavage”: ibid., pp. 266-8.
1886. ‘‘ Report on Slaty Cleavage and Allied Rock Structures ” : Rep.
Brit. Assoc, for 1885, pp. 813-52.
1887. ‘‘On some Anglesey Dykes,” I and II: Geron. Mac., pp. 409-16,
546-52.
1888. ‘‘ Notes on the Geology of Mynydd Mawr and the Nantlle Valley”
ibid., pp. 221-6.
‘On some Anglesey Dykes,” III: ibid., pp. 267-72.
** Additional Note on the Blue Hornblende of Mynydd Mawr”
ibid., pp. 455-6.
«On the Eruptive Rocks of the Neighbourhood of Sarn, Caernarvon-
shire”: Q.J.G.S., vol. xliv, pp. 442-61.
1889. ‘‘ Notes on the Physics of Metamorphism”: Guon. Mac., pp. 15-20.
“‘ Local Thickening of Dykes and Beds by Folding”: ibid., pp. 69-70.
‘¢ Byes of Pyrites and other Minerals in Slate”: ibid., pp. 396-7.
The Bala Volcanic Series of Caernarvonshire (Sedgwick Prize Essay
for 1888), 8vo, Cambridge.
‘*Petrological Notes on Boulders from the Boulder-Clays of East
Yorkshire”: Proc. Yorks. Geol. Soc., vol. xi, pp. 300-7.
1890. ‘‘ Petrological Notes on Some of the Larger Boulders on the Beach
South of Flamborough Head”: ibid., pp. 409-28.
1891. ‘‘The Ancient Lavas of the English Lake District”: Naturalist,
pp- 145-7.
‘Notes on a Collection of Rocks from the Tonga Islands” : Got.
Mac., pp. 250-8.
(With J. E. Marr.) ‘‘ The Shap Granite and the Associated Igneous
and Metamorphic Rocks”: Q.J.G.S., vol. xlvii, pp. 266-327.
“‘ Petrological Notes on Rocks from the Cross Fell Inlier” : ibid.,
pp. 512-25.
*¢ Thermo-metamorphism in Igneous Rocks ”: Bul. Geol. Soc. Amer.,
vol. ii, pp. 16-22.
1892, ‘‘ Physical Geology in the Basin of the Colorado” : Natural Science,
vol. 1, pp. 205-10.
So ab lavs Lamprophyres of the North of Bngland; >; Gon. Mac.,
pp. 199-206.
** Porphyritic Quartz in Basic Igneous Rocks”: ibid., pp. 485-8.
1893. ‘‘ Norwegian Boulders in Holderness” : Natur alist, pp. 1-4.
“The Use of the Protractor in Field Geology”: Sci. Proc. Roy.
Dubl. Soe. (N.S.), vol. viii, pp. 12-20.
(With J. E. Marr.) “ Supplementary Notes on the Metamorphic
Rocks around the Shap Granite”: Q.J.G.S., vol. xlix, pp. 359- ak
‘On the Migration of Material during Thermal Metamorphism ”
Journ. Geol., vol. i, pp. 574-8.
“‘Extinction Angles in Cleavage - Flakes”: Min. Mag., vol. x,
pp. 239-40.
‘* Berthelot’s Principle applied to Magmatic Concentration” : GuOL.
Maa., pp. 546-7.
1894.
1895.
1896.
1898.
1899.
1900.
1901.
1905.
1904.
1907.
1908.
1809.
1910.
TON2:
Dr, Alfred Harker, F.R.S. 293
“‘Carrock Fell: a Study in the Variation of Igneous Rocks,” I:
Q.J.G.8., vol. 1, pp. 311-36.
yh The Evolution of Igneous Rocks”: Science Progress, vol. i,
. 152-5.
“¢ Ancient Volcanic Rocks”: ibid., vol. ii, pp. 48-63.
“**Cordierite in the Lake District” : Grout. Mac., pp. 169- 70:
“On some Variolitic Rocks on Carrock Fell” : ibid., pp- 551-8.
“*Carrock Fell: a Study in the Variation of Igneous Rocks,” II and
IIL: Q.J.G.8., vol. li, pp. 125-47.
Petrology for Students : an Introduction to the Study of Rocks under the
Microscope, 8vo, Cambridge. (Revised editions in 1897, 1902, and
1908, and French translation in 1902.)
**@n certain Granophyres, modified by the Incorporation of Gabbro
Fragments, in Strath (Skye) ”: Q.J.G.S., vol. li, pp. 320-8.
“The Natural History of Igneous Rocks. I. Their Geographical
and Chronological Distribution”: Science Progress (N.S.), vol. 1,
pp. 12-33.
“The Natural History of Igneous Rocks. II. Their Forms and
Habits”: ibid., vol. ii, pp. 203-18.
“*Glaciated Valleys in the Cuillins, Skye”: Gron. MacG., pp. 196-9.
“On the Average Composition of British Igneous Rocks”: ibid.,
pp. 220-2.
‘“ Notes on Subaérial Erosion in the Isle of Skye”: ibid.,
pp. 485-91.
(With C. T. Clough.) ‘‘On a Coarsely Spherulitic (‘ Variolitic’)
Basalt in Skye”: Trans. Edin. Geol. Soc., vol. ii, pp. 381-9.
*‘ Magnetic Disturbances in the Isle of Skye”: Proc. Camb. Phil.
Soe., vol. x, pp. 268-78.
“ Igneous Rock-Series and Mixed Igneous Rocks”: Journ. Geol,
vol. vill, pp. 389-99.
““On a Qacshion Relative to Extinction-Angles in Rock-Slices” :
Min. Mag., vol. xiii, pp. 66-8.
*‘Tce-Erosion in the Cuillin Hills, Skye”: Trans. Roy. Soc. Edin.,
vol. xl, pp. 221-52.
“The Sequence of the Tertiary Igneous Rocks of Skye”: GOL.
Mace., pp. 506-9.
“*The Overthrust Torridonian Rocks of the Isle of Rum, and the
Associated Gneisses”: Q.J.G.S., vol. lix, pp. 189-215.
(With C. T. Clough.) The Geology of West Central Skye, with Soay
(Mem. Geol. Surv. Scot.).
(With notes by C. T. Clough.) The Tertiary Igneous Rocks of Skye
(Mem. Geol. Surv. U.K.).
‘The Tertiary Crust-Movements of the Inner Hebrides”: Trans.
Edin. Geol. Soc., vol. viii, pp. 344-50.
“The Geological Structure of the Sgurr of Higg”: Q.J.G.8.,
vol. 1xii, pp. 40-67.
“Cordierite in the Metamorphosed Skiddaw Slates”: Naturalist,
; 121-3.
a BHC Ser eeechean tier Lava from the Lake District’: Gron. MaG.,
pp. 176-7.
** Notes on the Rocks of the Beagle Collection,” I: ibid., pp. 100-6.
‘‘Teneous Rock-magmas as Solutions”: Science Progress, vol. ii,
pp. 239-54.
(With contributions by G. Barrow.) The Geology of the Small Isles o,
Inverness-shire (Mem. Geol. Surv. Scot.).
The Natural History of Igneous Rocks, 8vo, London.
Tables for Calculation of Rock Analyses, Cambridge.
Presidential Address to Section C (Geology): Rep. Brit. Assoc. for
1911, pp. 370-81.
“* Petrology in Feat ee (Presidential Address to the Yorkshire
Naturalists’ Union): Naturalist, pp. 37-44, 69-73.
294 OC. T. Trechmann—Cretaceous Mollusca
1912. ‘*‘ Lamprophyre Dykes in Long Sleddale” : ibid., pp. 266-7.
1914. ‘‘ Fractional Crystallization the Prime Factor in the Differentiation
of Rock-magmas ” ;: Congr. Géol. Int. Comp.-Rend., xii, pp. 205-8.
““The Sgurr of Higg: some Comments on Mr. Bailey’s Paper”:
Guo. Mac., pp. 306-8.
**Some Remarks on Geology in Relation to the Exact Sciences, with
an Excursus on Geological Time” (Presidential Address to the
Yorkshire Geological Society): Proc. Yorks. Geol. Soc., vol. xix,
pp. 1-13.
1916. ‘‘ Differentiation in Intercrustal Magma- Basins”: Journ. Geol.,
vol. xxiv, pp. 554-8.
1917. Presidential Address to the Geological Society of London, delivered
February 16 (see Reports and Proceedings, Grou. MaG., pp. 191-2,
April, 1917).
Il.—Crersacvous MoxnztuscaA From New ZEALAND.
By C. T. TRECHMANN, M.Sc., F.G.S.
PLATES XIX AND XX.!
InrTRODUCTION.
WING to incomplete paleontological knowledge, the true age
and correlation of the various divisions of the great Mesozoic
series of New Zealand, which, together with the Maitai Series, forms
such an important element in the structure of the country, has long
remained a matter of uncertainty. In consequence the idea has to
some extent taken hold among New Zealand geologists that the
Mesozoic faunas, owing to supposed conditions of isolation, show
archaic features. It was explained that certain Permian forms
occurred in the Trias and that Trias forms may have persisted into
Jurassic times, and to a still greater extent that a Cretaceous fauna
lived on in this portion of the earth into the Tertiary period.
On going further into these questions I find no support for the
theory, and in the case of the Cretaceous, a comparison of the fauna
of the Senonian with corresponding faunas of Australia and especially
of South America shows that the isolated survival theory is un-
tenable. ‘The arguments adduced in its favour apply equally well to
the Cretaceous of South America and other parts of the Indo-Pacific
region as they do to New Zealand.
It must be remembered that the present isolation of New Zealand
as a land mass is a phenomenon of late geological time. In the
Permo-Carboniferous period there was as much or more land in the
Southern Hemisphere as there now isin the Northern. The Cretaceous
and Tertiary faunas of New Zealand point toa much closer connexion
with South America than obtains at the present day. The number
of species of recent Mollusca common to the coasts of New Zealand
and Tierra del Fuego is now very slight.
In a paper recently published in this Magazine? I showed that the
Maitai Series contains a fauna which agrees, so far as it goes, exactly
with that of the marine Permo-Carboniferous of New South Wales
1 Plate XXI will appear with the second part in the August Number.
2 “The Age of the Maitai Series of New Zealand’’: GOL. MAG., N.S.,
Dec. VI, Vol. IV, pp. 53-64, Feb. 1917.
from New Zealand. 2
and Tasmania, but that the Maitai beds differ from the Permo-
Carboniferous of Gondwanaland in being entirely marine.
I also showed in a recent communication to the Geological Society
that the Kaihiku, the lowest known Mesozoic fossil-bearing horizon
in New Zealand, contains fossils of late Middle or early Upper Trias,
and is not as was formerly supposed of Permian age, and that the
Carnic, Noric, and Rhetic horizons of the Upper Trias are well
represented.
The Jurassic still remains the greatest terra incognita in New
Zealand paleontology, and owing to the discontinuous nature of the
outcrops, the scarcity and indifferent state of preservation of the
fossils, its study will involve some difficulty. Several horizons seem
to be represented by the fossils, of which I have a considerable
collection. A knowledge of the Jurassic horizons which occur in
New Zealand is an important matter, because the determination of
the highest Jurassic and the lowest Cretaceous beds will indicate the
time mits during which New Zealand first became a land surface.
It now seems to me quite clear that the New Zealand continent,
and the present New Zealand is the relic of a former land mass both
of continental dimensions and of continental faunal character,
originated some time about the period of the final fragmentation of
Gondwanaland. I am also inclined to think that its compression
and uplift are among the phenomena of readjustment consequent
upon that event.
The Cretaceous rocks form the basal portion of the newer or
covering series, and where they occur they rest, as in Chili and the
Californian coast ranges, with a most pronounced unconformity on the
denuded edges of the folded and in part metamorphosed rocks beneath
them. The lowest Cretaceous marine horizon present will afford us
knowledge when the sea began once more to transgress upon the
margins of the old peneplaned and lowered land mass which had
arisen and been partly denuded during the period intervening, so
far as we know at present, between very late Jurassic and Upper
Cretaceous times.
The outcrops of the Upper Cretaceous beds in New Zealand are
well shown by Professor J. Park on a small-scale map.'
They occur in six or seven more or less isolated patches of greater
or less extent. The relations of the Cretaceous to the overlying
Tertiary series have given rise to much discussion, into which
however I do not propose to enter in the present paper.
On the eastern side of the Alpine chain in the middle part of
the South Island, in the Waimakariri and Waipara gorges, the
marine Upper Senonian rests on the upturned edges of the older
rocks. This condition of things obtains also at Quiriquina, on the
coast of Chili. In the north-eastern part of the South Island and
apparently also on the eastern side of the North Island some earlier
Cretaceous beds with Jnoceramus occur. In this connexion it is
important to notice that in South Patagonia, between Lago
Argentino and Last Hope Inlet, on the eastern side of the Cordillera,
the Upper Senonian rests on beds containing Jnoceramus Steinmannt,
1 The Geology of New Zealand, 1910, sketch-map.
A Are
296 C. T. Trechmann—Cretaceous Mollusca
Wilckens, which are Upper Cretaceous but probably still of
Senonian age.
The faunal and stratigraphical details in New Zealand still remain
to be worked out, especially in the North Island, but the facts
already known point to a north to south as well as to an east to west
transgression of late Cretaceous beds, with a further overstep of the
Upper Senonian to the south-west across the earlier upper Cretaceous
beds beneath them. Mr. H. Woods has recently examined some
Cretaceous fossils belonging to the New Zealand Survey collections and
concludes that two distinct faunas occur. The older of these occurs
at Coverham, in the middle Clarence Valley in the north-east corner
of the South Island, and is of approximately Upper Greensand or
Gault age. The younger fauna of Upper Senonian age occurs at
Amuri Bluff on the north-east coast of the South Island, at Selwyn
Rapids, and other localities.
I understand that only the Lamellibranchs of Selwyn Rapids
were examined by Mr. Woods. His work, however, is not published
yet. Professor P. Marshall has recently investigated a very interesting
and rather extensive fauna which occurs at Wangaloa, on the south-
east coast of the South Islandsouth of Dunedin. It is clearly newer
than the Upper Senonian faunas above-mentioned, but must, on
account of the presence of Pugnellus, in my opinion, still be referred
to the Cretaceous. I should regard it as Danian or Maestrichtian.
The object of the present paper is to describe a series of fossils
other than the groups already described by Mr. Woods or those at
present under description by Professor Marshall, which throw further
light on the age and correlation of some of the Cretaceous beds of
the South Island of New Zealand.
All the specimens described were collected by myself, so I can
guarantee the accuracy of the localities and horizons.
Tar Locanivizs.
Selwyn Rapids.
This locality is situated at the base of the eastern foothills of the
Southern Alps about 36 miles west of Christchurch. The railway
station is Glentunnel, and the outcrop forms a series of rapids
in the Selwyn River about a mile from the station. The beds
consist of a series of glauconitic greensands more or less concretionary.
In the bed of a tributary creek a few hundred yards away there are
several enormous spherical concretions? 5 or 6 feet in diameter
1 Nature, March 22, 1917, p. 79.
? Similar concretions occur at Hampden, in North Otago, in beds apparently
of the same age that crop out on the seashore. The concretions are surrounded
by a casing of stony material in which the finest cone-in-cone structure I have
ever seen is developed. The apices of the cones as a rule are directed towards
the centre of the nodule, and the bases of the cones on the outside assume
forms that suggest floral structures. The outer skin of the septaria is a few
inches thick and is generally loose and detached from the concretion and is
easily broken off. ‘his together with the presence of yellow calcite veins
which pass in all directions through the septaria suggests that the cone-in-cone
structure is connected with a contraction of the inner portion of the septarian
concretions. These large septarian nodules are rather sparingly distributed in
from New Zealand. 297
that show sections of Conchothyra and other fossils on the weathered
surfaces. These concretions are extremely hard in places.
At the Rapids the fossils are very badly preserved in the softer
rock, but the harder portions exhibit many sections of well-preserved
fossils on the waterworn surface, but the rock is so hard that
a hammer and chisel are of little use. On one visit, however,
I employed a man to put some half-dozen shots of gelignite into the
most likely-looking places, with the result that a large quantity of
rock was broken up and became available for collecting.
The fossils show some unequal distribution in this bed, and
Conchothyra, Aplustrum, and other forms occur in little clusters or
nests. Lamellibranchs and Gasteropods are the chief fossils, but
scales and bones of fish also occur, the former rather plentifully.
I was fortunate in obtaining two Ammonites and a Belemnite, neither
of which seems to have previously been recorded from this locality,
and which establish the Mesozoic age of the beds beyond question.
T collected a large number of Lamellibranchs, but as Mr. Woods has
described those of the old Survey collection from this locality I await
the appearance of his memoir before I describe them or record any
new forms there may be among them.
Waipara Gorge.
In the Waipara Gorge, about 85 miles north of Christchurch, there
is a glauconitic sandstone full of marine shells a very short distance
above the local base of the Cretaceous and below the well-known
concretionary greensands with Saurian bones. Some of the fossils
are very much rolled, as though it had been an old shore-line, but
unfortunately they are badly preserved. Ostrea is very plentiful,
and there are many specimens of a shell I took to be Conchothyra
parasitica, but which turns out to be an apparently undescribed form
of Pugnellus. The Waipara Gorge affords the most important con-
tinuous section in New Zealand of the Cretaceous and Tertiary beds.
Waimakariri Gorge.
This locality is about 40 miles west-north-west of Christchurch.
The station is Kowai Bush, and a section of Cretaceous beds resting
unconformably on semi-metamorphic greywackes and argillites of
uncertain age is exposed in a deep gorge of the river. The fossiliferous
band is not far above the junction, and consists of some 3 feet of
glauconitic greensand crowded with Conchothyra parasitica, the only
other fossil being an occasional badly preserved valve of Zrigonia
Hanetiana.
Wangaloa.
This locality is on the coast about 35 miles south-west of Dunedin,
and forms part of the Kaitangata Coalfield. Fossils occur in a
culcareous sandstone with some glauconite. Professor Marshall has
a bed of blackish-grey calcareous shale which shows no trace of cone-in-cone
structure. I noticed in some places that where the coneretions had been
affected by subsequent pressure in the bed the action of the pressure tended
to bate again the cone-in-cone structure in the outer layer of the
nodules,
298 CO. T. Trechmann—Cretaceous Mollwsea
recently shown that the fauna here is distinct from the usual
Cretaceous such as occurs at Selwyn Rapids, and that a shell which
occurs here and was formerly supposed to be Conchothyra parasitica
is really a new species of Pugnellus. Neither Ammonites nor
Belemnites have yet been found in this bed. Marshall has recently
published ! a provisional list of fifty-two species of Mollusca from this
locality which seems to include a considerable number of Tertiary
Oamaru forms and even some recent species. He is at present
investigating this fauna more closely. I made a fairly large
collection one day at this locality, but I await Professor Marshall’s
work before reporting on them.
PaLZONTOLOGY.
Triconta cf. Hanetrana, d’Orb. (Pl. XXI, Fig. 5.)
Voyage dans l’Amérique Paléontologie, 1842, p. 127, pl. xii, figs. 14-16.
Philippi, Die quataren und tert. Versteinerungen Chiles, 1887, p. 199,
pl. xlii, figs. 1-3.
Steinmann, ‘‘Die Gastropoden u. Bivalven der Quiriquina-Schichten ”’ :
N.J. fiir Min., Beilage Bd. x, p. 101, pl. vii, figs. 8, 9, 1895.
Hector, Catalogue Ind. and Col. Exhibition, 1886, p. 64, fig. 5, Trigonia
sulcata.
The only other shell I saw in the Conchothyra bed in the
Waimakariri Gorge was a Zrigonia, which occurred as single valves
in a friable and fragmentary condition. I collected the pieces of one
and succeeded in joining them together. It is undoubtedly the
shell that Hector illustrates without any description under the name
Trigonia suleata. The curious double sculpture on the anterior part
of the shell makes this quite certain. Steinmann notices Hector’s
figure, and compares it with 7. Hanetiana from Quiriquina, in Chili,
and remarks ‘‘ that of all known forms of Zrigonia the only one
which compares with Z. J/anetiana is one illustrated by Hector
under the name 7’ suleata from the lower (sve) Cretaceous of New
Zealand. Both forms are obviously very closely related and represent
a genuine Pacific form, for which it would be best to institute
a special group’’. He goes on to say that it does not fall well into
any of Lycett’s Zrigonia groups.
My specimen is a right valve, and unfortunately lacks the hinder
part, but enough remains to give a fair description of it. The beak
is rather anterior and the shell considerably elongated behind. The
ridge which passes from the beak to the hinder part is bluntly
angular, the sides making nearly a right angle with one another, and
in front there is a wide shallow groove almost devoid of sculpture.
Between this and the rounded anterior margin the surface is
ornamented with broad and shallow concentric growth grooves which
are crossed obliquely by a series of about six broad and low ridges,
which are arranged parallel to the main posterior ridge and gradually
diverge and increase in size as they pass from the upper anterior part
of the shell backwards to the lower margin. Where they are
strongest they tend to obliterate the concentric grooves of growth.
The teeth cannot be seen. Height 50 mm.
1 “Relations between Cretaceous and Tertiary Rocks’’: Trans. N.Z. Inst.,
vol. xlviii (new issue), p. 114, 1915.
ay from New Zealand. 299
I am inclined to think the New Zealand shell is identical with
T. Hanetiana, but owing to the poor condition of the only specimen
I collected I cannot be quite certain.
Wilckens! describes another form, Z. ecplecta, from the Upper
Cretaceous of Baguales in South Patagonia, which, though larger, is
certainly related to Z. Hanetiana, but on which the cross ribs are
confined to the upper anterior portion of the shell, and the concentric
furrows are much stronger.
T. Hanetiana belongs to the commonest fossils of the Chilian
Upper Cretaceous, and together with Cardium acuticostatum, d’Orb.,
is regarded as a leading fossil of the Quiriquina Beds.
I found no Trigonias at Selwyn Rapids, but I believe they occur
there.
Denrarium sp. (Pl. XXI, Fig. 10. X 2 nat. size.)
Shell slightly curved, increasing slowly in size, rather thin, and
almost circular in section. The surface is rather rough, and the
growth-lines are well marked. A specimen I collected resembles
D. Chilensis, @Orb., which is common at Quiriquina, but is without
the longitudinal strie that occur on the thin end of that species.
It is comparable also with D. Cazadorianum, Wilckens, from South
Patagonia.
Locality.—Selwyn Rapids. Dentaliums of fairly large size are
common, generally as casts in some parts of the rock.
DoRRITEDeA sp. (Ply XIX, Fig Il. x.23 nat. size.)
Shell small, consisting of seven whorls, which increase very
gradually. The test is rather thin, the sutures are shallow, and
each whorl is decorated with seven or eight very faint spiral raised
ridges.
Locality.—Selwyn Rapids.
Curysostoma SELWYNENSIS, sp. noy. (Pl. XXI, Figs. 4a, 0.)
Shell very small, thick, and globose, consisting of five whorls.
‘ Surface smooth and rounded, sutures shallow. There is a faint
umbilicus which is more or less covered by a reflected callus extension
of the inner lip. The outer lip, though broken, seems to have been
sharp. Height 5mm. I can find no described form in the Indo-
Pacific Cretaceous resembling this small and insignificant-looking
shell, and so am constrained to give it a new specific name. The
only living representative of the genus to which it certainly seems
to belong is a beautiful shell, C. paradoxum, Born, found on the
shores of New Caledonia.
Locality.—Selwyn Rapids, one specimen.
Narrca (Husprra) vartasinis, Moore. (Pl. XIX, Figs. 8-10.)
Charles Moore, Quart. Journ. Geol. Soc., vol. xxvi, p. 256, pl. x, fig. 15, 1870.
Jack & Htheridge, Geol. and Pal. Queensland, 1892, p. 485, pl. xxxi, figs. 2, 3.
RB. B. Newton, Proc. Malac. Soc., vol. xi, pt. iv, p. 232, pl. vi, figs. 21-3, 1915.
The New Zealand form of this Australian fossil is rather variable.
One specimen (Fig. 8) has four volutions, is broader than it is high,
' Berichte der Naturf. Gesell. z. Freiburg, Bd. xv, p. 37, pl. vii, figs. 2, 3,
1907.
300 C. T. Trechmann—Oretuceous Mollusca
and is rather depressed. ‘The body-whorl is large and globose and
increases rapidly in size. The surface is rather eroded and bears
closely spaced rather foliaceous growth-lines. The suture is some-
what deep and the whorls are not flattened below it, and there are no
parallel striz on the basal part of the body-whorl. It measures
16mm. high and resembles a specimen figured by Jack & Etheridge,
pl. xxxi, fig. 2. Another specimen (Fig. 9) differs in having
a more elevated spire, the suture is not insunken and the whorls are ~
flattened just below it, and the body-whorl is relatively smaller and >
less swollen. About six fine rounded concentric ridges occupy the
base of the body-whorl near the umbilicus, and the growth-lines are
much less strongly marked than in the first variety. It is smaller
in size and resembles the specimen figured by Jack & Etheridge,pl.xxxi,
fig. 3. Another smaller specimen (Fig. 10, x 14 nat. size) resembles
the last, but the concentric ridges occupy the whole of the body-whorl..
This shell agrees in every way with the Australian form, and is the
only Australian Cretaceous fossil I found in the New Zealand rocks.
Mr. R. B. Newton has recently discussed the generic affinities of this.
shell in a paper quoted above dealing with the fossils of the opal
deposits of the interior of New South Wales.
It occurs in the Rolling Downs Formation of the Lower Cretaceous,
and also in the Desert Sandstone, Upper Cretaceous, in Australia.
I have a specimen from the opal deposits of Whiteclifts, New
South Wales.
Locality—Selwyn Rapids, where it is not scarce. I did not find it
in any other locality, and this is the first record of the occurrence of
this typically Australian form in New Zealand and forms the sole
connecting link among my specimens with the Australian Cretaceous.
Neritopsis(?) SprreHri, sp. nov. (Pl. XIX, Figs. 12—15.")
The shell consists of four or five whorls, and in young specimens
is thin and oval in shape. In the adult state it is more rounded
owing to flattening of the spire and rapid enlargement of the body-
whorl. The spire in immature specimens is pointed and rather
elevated, but in the adult specimen it is flattened through erosion or
wear. In the largest example there is a faint umbilicus, the peristome
is entire, and the inner lip is somewhat detached from the body-whorl.
The lip is thickened for some distance back from the margin, but
ends in a sharp rim. The body-whorl is decorated with about.
fifteen raised concentric parallel rounded ridges, alternating with
furrows of about the same width and depth. On the earlier whorls
the furrows are less strongly marked. The growth-lines are rather
faint, but are interrupted here and there on the body-whorl by
a strong furrow.
In the absence of knowledge of the operculum or of the animal it.
is impossible to fix with certainty the genus of this shell, as many
genera quite unallied to one another develop parallel concentric
furrows, such as Cinulia, Dolium, Pyrula, Fossarus, and many others.
The moderate thickness of the shell and increasing thickness of
the adult lip and sharpness of the aperture point to Meritopsis
1 Fig. 15 is x 2 nat. size.
from New Zealand. aul
as being the most likely genus. It also resembles Vanzkoro, but the
shell seems too thick and the inner lip too strongly developed.
The partial detachment of the inner lip from the body-whorl and the
complete peristome suggests the genus Lossarus, which together with
Vamkoro has a horny operculum, whereas that of Nerztopsis is thick
and stony. There is no trace of columellar folds nor of a reflected lip
which might connect it with Cinulia or Hriptycha.
. The erosion or battering which the spire has suffered in the adult
specimen points to its being some shore-loving form, but whether of
the Littorinide or Neritopside is uncertain, but I think the genus
LNeritopsis is the more likely one.
Locality.—Selwyn Rapids.
The only species I can trace which at all resembles the present
form is Vanikoro Kiliant, Wilckens,! which occurs at Snow Hill and
Seymour Island in Antarctica. But this is a very small shell and
consists only of three to four whorls and has fourteen spiral ribs, the
spaces between which are not always equal and the ribs are preserved
only on the last whorl. I take the opportunity of naming this shell
after my friend Dr. R. Speight, director of the Christchurch Museum,
who has published many papers on New Zealand Geology, and who
assisted me to collect several of the Cretaceous fossils.
ConcHoruyra Parastrica, McCoy. (Pl. XX, Figs. 4, 5.)
Hector, Cat. Ind. and Col. Exxhib., 1886, p. 58, fig. 4.
Park, Geol. New Zealand, 1910, p. 90, pl. v (after Hutton).
This extraordinary Gasteropod is the most abnormal of the curious
group of the Pugnellids. The smooth callosity of the inner lp
is more exaggerated than in any other species of the group, and
in some specimens it extends beyond the apex and sometimes almost
buries the spire. The thickened claw-like outer lip is very large and
heavy, and the growth-lines and ridges on the body-whorl are very
exaggerated.
If the genus Conchothyra is to be retained—and in view of its
frequent mention in New Zealand geological literature and the great
specialization of the shell in question I think it should be—it may be
re-defined as follows :—
Shell as in Pugnellus, but the early whorls are smooth and devoid
of nodes or ribs. Spire short and in fully grown specimens almost
buried by the labial callosity, and often scarcely visible owing to
erosion. The lines and ridges of growth are coarse and prominent
on the last whorl. The anterior channel of the mouth is deep and
narrow, the posterior channel is shallower and more or less semi-
circular in shape. The outer lip is much thickened and often greatly
prolonged.
I think this curious molluse may have been of a sluggish character
and have lain partly buried in sand. Both the great weight of the
shell and its frequent erosion suggest this mode of life. That part of
the body-whorl on the back below the spire is generally very thin,
1 “Die Anneliden, Bivalven, u. Gasteropoden der antarktischen Kreide,
1910’: Wissensch. Ergebnisse der Schwed. Sudpolar Exped., p. 77, pl. iii,
figs. 28a, b.
302 0. T. Trechmann—Cretaceous Mollusca
apparently by absorption or erosion. In one of my specimens there
is a small Anomia attached to the surface near the inner lip which
suggests that the shell may have lain mouth upwards in the sand.
Locality.—In the Upper Waimakariri Gorge there is a bed about
3 feet thick not far above the local base of the Cretaceous almost
made up of thousands of these shells, some perfect and others broken.
They show considerable variation in the degree of growth of the
shelly callosity and the extension of the lip. The only other fossil
that I found associated with them in this locality were a few valves
of Trigonia Hanetiana, d’ Orb. At Selwyn Rapids the shell is less
plentiful, and is better preserved in the harder parts of the rock, but is
in all respects similar to the specimens at Waimakariri.
It seems, as one might expect in so specialized a shell, to have
a restricted vertical range, and may be regarded as a characteristic
fossil of the Upper Senonian.
This form is apparently quite absent from the higher Wangaloa
Beds, where it is replaced by a beautiful shell recently described by
Professor Marshall as Pugnellus australis.
Pouenettus Marsa, sp. nov. (Pl. XIX, Figs. 1-4.)
The shell consists of six whorls, the last one large and inflated.
Above the middle of each whorl there is a row of blunt nodes, and
below these on the last whorl a row of smaller and less prominent
nodes which in some specimens coalesce into a raised ridge. The
sutures are shallow. ‘The outer layer of the shell bears very fine
concentric raised lines.
The lip is not developed to the exaggerated extent it is in some
forms of Pugnellus. The outer lip is extended and swollen, and ends
in a rounded claw-like protuberance which is very easily broken off.
Anteriorly there is a channel, but the shell is not drawn out.
Posteriorly there is a wide semicircular channel formed by the
swollen lip of the shell. The callosity of the inner lip reaches
in most specimens to the top of the third whorl from the mouth, and
in one or two examples it extends above this nearly to the apex. It
is a shell of moderate size, the height being about 26mm.
This shell was formerly erroneously supposed to be a Struthiolaria
or Pelicaria, and a specimen was recently identified as such by
Mr. Suter, and Prof. Marshall! remarks that it is the first occurrence
of the essentially Tertiary form Struthiolarva in Cretaceous rocks.
I obtained, however, nine or ten perfect examples with entire lips
and can definitely say that itis a true Pugnellus. It often happens
that the specimen is immature or the lip is missing when the
sculpture on the earlier whorls of the shell certainly recalls that on
the recent Pelicaria. However, in no Struthiolaria that I have seen
does the labial callosity extend to beyond the lower half of the
penultimate whorl. The same remark applies to Pelicaria, which
has in addition a thin smooth shelly deposit covering the back of the
last and penultimate whorl. Neither Struthiolaria nor Pelicaria
has the thickened and swollen outer lip characteristic of Pugnellus
which is so conspicuous in the present shell.
1 Trans. N.Z. Inst., vol. xlviii, p. 118, 1915.
from New Zealand. 303
Locality.—Selwyn Rapids, where it is rather common.
I name this species after Professor P. Marshall, who has done so
much in elucidating the geology of New Zealand and in calling
attention to the problems of the Cretaceo-Tertiary question in the
South Pacific region.
PuenEettus WaAIPARENSIS, sp. nov. (Pl. XX, Figs. la, 0.)
The spire is moderately elevated and the shell consists of six whorls.
The shell is almost completely overgrown up to the summit of the
spire with a platy extension of the lip, and only when this is broken
away is the spire visible and the nodes and ornamentation of the
whorls seen. The earlier whorls are decorated with folds which develop
into elevated and rather sharp nodes. These are placed in a diagonal
position on the shell rather above the suture on the penultimate
whorl, and are faintly visible on the body-whorl where they occur
above the median line. Below these nodes on the last whorl there is
a blunt faintly raised ridge.
A series of fine, rather wavy, spiral, raised lines occur on the
penultimate whorl and are faintly seen on the body-whorl below the
ridge. They run somewhat irregularly and are not exactly parallel
to one another, but approach and recede again, a peculiarity already
noticed by Wilckens in the case of Pugnellus Hauthali,! which he
describes from South Patagonia. The anterior channel of the lip is
not produced, and the outer margin of the lip is not swollen to an
unusual extent for a Pugnellus.
This shell approaches P. Hauthali in having the spire completely
covered with a leafy shell growth and in the. diagonal arrangement
of the elongated and sharp nodes and in the curious non-parallel
arrangement of the spiral lines. It differs in the spire being more
elevated and the anterior channel not being elongated and the outer
lip being less swollen and extended.
Locality.—Waipara Gorge, in beds with Osérea near the local
- base of the Cretaceous and well below the Saurian concretionary
beds. It occurs plentifully, but often rolled and poorly preserved.
It has hitherto been mistaken for Conchothyra parasitica, and
I thought it was a small variety of that shell, but I find on
developing my specimens that it is a Pugnellus that I cannot identify
with any described form. I found no Conchothyra in the bed in
which it occurs.
Puenetius austratis, Marshall; variety. (Pl. XX, Figs. 2a, d.)
‘Trans: N.Z. Inst., vol. xlviii, p. 120, pl. xi, figs. 1-3, 1915.
Professor Marshall has recently described a highly decorated shell
which occurs rather commonly at Wangaloa. When I visited that
locality in his company I collected several examples of the shell, two
of which, when developed, prove to be excellently preserved. One ot
them closely resembles his type-specimen, Fig. 2, but the other
differs in having a much more exaggerated development of the
lip than any of his three figured examples and is apparently an aged
specimen.
! Berichte der Naturf. Gesell. z. Freiburg, Bd. xv, p.18, pl. iv, figs. 2a, 6, 1907.
yA ba Ate
Ne A SCAR fae :
304 OC. T. Trechmann—Cretaceous Mollusca, New Zealand.
The spire is almost concealed, and the callosity extends far beyond
it and is produced into a finger-like process which is bent away from
the spire. The outer lip is much thickened and produced upwards,
and the interior portion of the lip is provided with a second channel
through excessive growth of the callous margin. I think this
variety, Figs. 2a, 6, is sufficiently distinct to warrant its illustration
for comparison with the more normal type, Figs. 3a, b, and to
complete the illustration of the Pugnellid shells which have so far
been found in New Zealand.
Locality.—Wangaloa. Maestrichtian (?).
ALARIA Sureri, sp.nov. (Pl. XIX, Fig. 5. x1} nat. size.)
The shell consists of eight whorls which increase gradually in
size. ‘The lip of the last whorl is moderately expanded to a simple
curved outline and is not digitate. It ends anteriorly in a blunt
termination beneath which there is a shallowchannel. The posterior
margin of the lip does not seem to be channelled, and the labial
expansion extends about half-way up the penultimate whorl. The
whorls are decorated with rather widely spaced curved ribs, recalling
those of Scalaria or of the recent Aporrhais occidentalis, Beck. On
the last whorl these ribs reach from the suture to rather beyond the
middle line, where they meet a blunt ridge. The whole surface of
the outer layer of the shell is covered with very fine parallel raised
concentric lines which continue over the ribs. Length about 85 mm.
The earlier whorls of this shell strongly recall those of a Scalaria,
and resemble a fragment of six whorls from Quiriquina that
Wilckens illustrates! under the name S. araucana, Phil., only that
the varices are rather closer together than they are on the New
Zealand shell.
Locality.—Selwyn Rapids. I name this species, which I cannot
identify with any described form, after Mr. H. Suter, of Christ-
church, the leading authority on the recent Mollusca of New
Zealand.
AporRHAIS GREGARIA, Wilckens. (Pl. XIX, Figs. 6, 7.)
Berichte der Naturf. Gesell. z. Freiburg, Bd. xv, p. 16, pl. iii, figs. 10-13;
jolla hye tiie, ILS TKOG/
The shell consists of seven or eight whorls, the last one of which
is swollen and expanded. The margin is channelled anteriorly and
is not digitate, but extends to a rather sharp projection, which is
produced backwards in a direction almost parallel with the spire.
Between this projection and the body of the shell the lip has a broad
shallow posterior channel. The shell is ornamented with a line of
nodes which occur rather above the median line of the last whorl.
Beneath them on the last whorl there is a series of much smaller and
more numerous nodes that tend to coalesce into a raised ridge. The
surface is decorated with a series of more or less continuous parallel
raised ridges which are most apparent above the nodes on the
penultimate whorl and on the lip. Growth-lines are rather prominent
and irregular especially on the last whorl.
1 N.J. fiir Min., Beil. Bd. xviii, pl. xviii, fig. 1, 1904.
ihe ey oP as!
ot) ay *
bape te i
Say
ca rs
Grou. Maa., 1917. Prare XIX.
G. M. Woodward, del. Bale & Sons, imp.
UPPER CRET .EHOUS GASTEROPODA, NEW ZEALAND.
mise
i
eso yl
rare
ren
Grou. Maa., 1917. PratTE XX,
sas
G. M. Woodward, del. Bale & Sons, imp.
UPPER CRETACEOUS GASTEROPODA, NEW ZEALAND. q
GW. Tyrrell—Tertiary Dykes of the Clyde Area. 305
Iam fortunately able to identify this form with certainty with
the above shell, which Wilckens describes from Cazador, Sierra
Contreras, and other places in South Patagonia between Lago
Argentino and Last Hope Inlet. He illustrates several examples
and says that the species is one that does not compare closely with
any other Aporrhats known to him.
Locality.— Selwyn Rapids. I collected two specimens with spire
and lip, one of them in fine condition which required to be laboriously
chipped out and pieced together again. The spire in the better
specimen (Fig. 6) is rather higher and more tapering than in the other.
The shell that Hector! figures under the name Rostellarta WORE
is probably intended to represent this species.
EXPLANATION OF PLATES XIX AND XX.
All figures natural size unless otherwise indicated. All except Pugnellus
australis are of Upper Senonian age.
PLATE XIX.
FIGS.
1-4. Pugnellus Marshalli, sp. nov. Selwyn Rapids.
5. Alaria Suteri, sp. nov. Selwyn Rapids. X 14 nat. size.
6. Aporrhais gregaria, Wilckens. Selwyn Rapids.
Bs Ditto, another specimen showing upward extension of the lip. Selwyn
Rapids.
8-10. Natica (Huspira) variabilis, C. Moore. Selwyn Rapids. Fig. 10 is
x 14 nat. size.
11. Turritella sp. Selwyn Rapids. x 24 nat. size.
12-15. Neritopsis (?) Speighti, sp. nov. Sela Rapids. Fig. 15is x 2 nat. size.
PLATE XX.
_ la, b. Pugnellus Waiparensis, sp. nov. Waipara Gorge.
2a, b. Pugnellus australis, Marshall, variety. Maestrichtian (?). Wangaloa.
3a, 6. Pugnellus australis, Marshall, normal form. Wangaloa.
4, Conchothyra parasitica, McCoy. Waimakariri Gorge.
5. Ditto, same locality. Another specimen.
(To be concluded in the August Number.)
IIi.—Some Tertiary Dykes of THe CrypE AREA.
By G. W. TyRRELL, A.R.C.Se., F.G.S., Lecturer in Mineralogy and
Petrology, Glasgow University.
INTRODUCTION.
(J\HE very numerous Tertiary dykes of the Clyde islands (Arran,
Bute, and the Cumbraes), and of the adjacent mainland and
peninsulas, have been little studied either from the geological or
petrographical point of view; but they are of great interest, not
only in themselves, but as providing a link between the dykes of the
better known areas of the North of England, and of Skye and Mull.
The material is not yet gathered on which could be based a complete
account of the series. The present paper is designed to present
a full description of a hitherto unrecognized type of Tertiary dyke,
typically exposed in the Great Cumbrae, and to indicate its relation-
ships to other types already described from Mull and the North of
England. Furthermore, a few other dykes from the Clyde area, all of
basaltic composition, will be briefly described.
1 Cat. Ind. and Col. Exhibition, 1886, p. 58, fig. 3.
DECADE VI.—VOL. IV.—NO. VII. 20
306 G. W. Tyrrell—Tertiary Dykes
The dykes of Arran have been the subject of geological inquiry
since the beginning of the nineteenth century (Harker, 1903,
Bibliography, pp. 181-901). Their extraordinary abundance has
attracted much attention, but little is as yet known of their petro-
eraphical characters. Still more is this the case in regard to the
Tertiary dykes of Bute, the Cumbraes, and the Ayrshire and
Argyllshire mainland. Sir A. Geikie has gathered together all that
was previously known of the geological and petrographical characters
of the Tertiary dykes, and has supplemented it with the facts gained
during his own numerous traverses of the Tertiary volcanic districts
(1897, pp. 118-80). He distinguishes the great solitary dykes
(e.g. the Cleveland dyke of the North of England) from the gregarious
dykes, which are shorter, narrower, more basic, than the solitary
dykes, and are closely crowded together in restricted areas.
Petrographically he divides them into four groups—(1) normal
basalts and dolerites; (2) andesites; (3) trachytes (Cowal); (4) acid
dykes, felsite, quartz-porphyry, pitchstone, ete., which are arranged
in the order of age. The first group, basalts and dolerites, include
by far the greater number of the dykes, especially those of the
gregarious type, whilst the great solitary dykes generally belong to
the second group, the andesites.
The Geological Survey memoir on Cowal (1897, pp. 126- 7)
contains abundant geological information as tothe Tertiary dykes of
that part of the Argyllshire mainland bordering the Firth of Clyde.
Sir J. J. H. TYeall’s petrographical descriptions of some of these
dykes suggest relationships to the Cumbrae dykes described later in
this paper.
The Tertiary igneous rocks of Arran, South Bute, and the
Cumbraes are the subject of a chapter by Dr. A. Harker (1908,
pp. 103-27) in the Geological Survey memoir on that area. In this
chapter the Tertiary dykes are briefly treated under the headings
dolerite and basalt, augite-andesite, pitchstone, and devitrified
pitchstones. One or two Arran dykes with special characters have
been previously described by me (Tyrrell, 1913, 1916) ; and Dr. W. R.
Smellie (1916) has recently described some of the Tertiary dykes
of Bute.
Tur Comprar Type or Tertiary Dyxr ( Cumbraite).
The Great Cumbrae is traversed by several large and finely exposed
Tertiary dykes of a peculiar petrographical character and striking
macroscopic appearance. ‘They consist of a black glossy rock, with
a tendency to vitreous lustre, in which are embedded numerous
phenocrysts of white or yellow, fresh, plagioclase felspar, which
proves to be near anorthite in composition. In the field they form
prominent wall-like exposures trending to the N.N.W., upon the
lowest raised beach which encircles the island. The Lion Rock,
near Keppel Pier, is one of these dykes which has been broken in
such a way that its profile suggests a couchant lion. It rises to
a height of 15 feet, with a thickness of 16 feet, whilst a second dyke
1 See list of references at end of paper.
“Um et, Ne a
aoe i wy Ds
De, vere
4;
of the Clyde Area. 307
adjacent to the Marine Biological Station at Millport attains a height
of 30 feet above the raised beach, and averages 20 feet in width.
The exposure from which the type-rock has been taken occurs on the
raised beach at Eerie Port on the north-west side of theisland. This
dyke is 29 feet wide, has a N.N.W. trend, and a slight hade to the
W.S.W. Its central part has locally a more vitreous lustre or
pitchstone-like appearance than other parts. Petrographical examina-
tion shows that this appearance is not due to greater richness in
glass, but to its slightly fresher character. All parts of the dyke
show small cavities partly or wholly filled with bitumen. This
dyke can be traced inland for about a mile, which is about as far as
the Lion Rock and the Marine Biological Station, where dykes can
also be traced. Other and smaller dykes of the same character occur
around the shores of the island.
Fic. la.—Cumbraite, N.N.W. dyke, Eerie Port, Great Cumbrae. x 20. Large
phenocryst of anorthite ; groundmass: laths of labradorite, enstatite,
augite, in base of dark class.
,, 1b.—Cumbraite (Eskdalemuir type), W.N.W. dyke, Waterhead Burn,
Muirkirk, Ayrshire. x 20. Microphenocrysts of labradorite and
magnetite; groundmass: felspar microlites, grains of augite and
enstatite, in base of dark glass.
Under the microscope (Fig. 1a) these rocks show phenocrysts
of plagioclase near anorthite, in a groundmass of laths of acid
labradorite (Abi Ani), enstatite, augite, and abundant glass. The
phenocrysts are extraordinarily fresh, with both Carlsbad and albite
twinning usually well developed. ‘They may reach a diameter of 1 cm.
Twinning, cleavage, and refractive index methods agree in deter-
mining the composition of the felspar as between Abus Ang and
Abjp ANgo, i.e. anorthite near bytownite. The mineral, moreover,
has a negative optical character which agrees with this determination.
All the crystals have a narrow border of optically positive labradorite
308 G. W. Tyrrell—Tertiary Dykes
(Ab, An,). The contact between the two felspars is remarkably
sharp, giving a well-marked “bright line” effect. The marginal
labradorite has the same width whatever the size of the phenocryst,
and has a very ragged, crenulated, or spiky margin against the glass
of the groundmass, as though the glass had penetrated along the
cleavage cracks. The anorthite phenocrysts carry numerous
globulitic inclusions and ‘‘ negative crystals’ of dark glass extended
parallel to 010. These are zonally arranged or confined to the
centres of the crystals. The groundmass shows labradorite laths
and pyroxene prisms embedded in a dark glass, the crystalline and
glassy matter being about equal in bulk. The felspars form
elongated laths, with bifid or trifid terminations, and a maximum
extinction angle of 28 degrees, indicating acid labradorite
{Ab; An;). The chemical analysis shows that the orthoclase
molecule must be present, but it does not appear in crystalline form,
and must be incorporated in the glass.
The pyroxene includes both enstatite and augite, which are
usually intergrown in characteristic fashion, with the augite always
occurring on the margins. A common appearance is of three prisms
in parallel position, two of augite on the margins, and a stout crystal
of enstatite occupying the centre. Frequently, however, the enstatite
occurs without the flanking augites, especially in the other Cumbrae
dykes. It then carries minute specks of magnetite in a marginal
zone. It is quite fresh, colourless, with straight extinction,
positive sign, and has the heavily outlined cross-fracturing often
seen in the orthorhombic pyroxenes. The augite is also colourless
and has an extinction of 36 degrees.
_ he apparently dark-brown or black glass of the groundmass may
be resolved under a high-power objective into a colourless or pale-
yellow glass darkened by innumerable black globulites. It also
carries numerous curved felspar microlites, and little strings
of iron-ore granules which may represent original microlites of
pyroxene. The apparently more glassy part of the Eerie Port
dyke differs from the stonier part only in the greater freshness of
its glass. The glass of the stony part always shows the beginnings
of devitrification.
The other dykes of this type in the Great Cumbrae differ from the
Eerie Port dyke only in minor details, such as the relative abundance
of phenocrysts or the glassy base.
Mopr.—An attempt was made to determine the quantitative
relations of the minerals in the Herie Port dyke by the Rosiwal
method, but owing to the presence of glass, the fine grain, and the
consequent uncertainty as to the exact boundaries of the ‘minerals,
the results must be regarded as only approximate. The anorthite
phenocrysts were estimated from a number of hand- -specimens.
Table I shows the results of measurements for the “stony” (1) and
‘‘olassy ’”’ (2) parts of the Herie Port dyke.
These figures show that this rock, if holocrystalline, would have
been dofelsic. The glassy material contains little or no ferro-
magnesian constituents, asshown later. As regards texture, the rock
is megaphyric (large phenocrysts), hyalocrystalline (glass and erystals
of the Clyde Area. 309
developed in approximately equal quantity), and perpatic (ground-
mass overwhelmingly predominant over phenocrysts).’
: TABLE I.
| te 2.
Anorthite (Ab; Ang) ! : 7 10
Labradorite (Ab; ae) ? : 31 26
Pyroxenes . 5 : 20 22
Glass . ; ‘ ; F 42 42
Specific gravity . 2-706 2-680
The composition of the glass may be calculated from the chemical
analysis (Table II, 1) by deducting the mineral constituents in the
proportions shown in Table I. After deducting 7 per cent of
anorthite (Ab; Ang) and 31 per cent of labradorite (Ab; An,), and
assigning all the T1002 and Fe,0O, to ilmenite and magnetite
respectively, the rest of the ferrous iron and lime with magnesia
and the proper quota of silica form just 20 per cent of pyroxene,
thus affording good evidence of the accuracy of both mineral and
chemical analyses. All the mineral constituents have now been
deducted; and as the ilmenite and magnetite may be held to
represent the dark globulites in the glass, the remaining potash,
soda, alumina, and silica must be present in the colourless glass,
which must have the approximate composition $iO:2, 80°4; Al, Os,:
9°9; NaeO, 3:7; K,O, 6:0. There is a small defect of Al. O, as
compared with the amount required to make orthoclase and albite
molecules of all the potash and soda. It is possible, therefore, that
there is a slight defect of Al,O,; in the analysis of the rock. From
these results it may be concluded with fair probability that, apart
from the dark globulites, there is no iron, magnesia, or lime in the
glass, and that it consists entirely of orthoclase, albite, and free
silica molecules.
Cuemicat Composition.
The chemical composition of the Cumbrae dyke and of the similar
dyke of Eskdalemuir, is set out in Table II, 1,2. Compared with
average andesite (II, 5) and average hypersthene-andesite (II, 6),
they have the same amount of silica and alkalies, less alumina, but
higher ferrousiron and lime. The Cumbrae types are therefore slightly
more femic than the average andesites, but have a somewhat more
sodic plagioclase felspar, as is well shown by the norms (Table III,
1, 2, 5, 6).
The comparison between the two cumbraites is hindered by the
non-determination of Ti O2 in the Eskdale rock; but the smaller
Al,O; and lime, and the higher ferrous iron and magnesia, of the
latter, cause a reversal of the relative proportions of diopside and
hypersthene in the norms of the two rocks (Table III, 1, 2). The
Eskdale rock is slightly more femic and less quartzose than the
Cumbrae rock, as is shown by the dashes following the symbols for
class and order in the former.
1 Tddings, Igneous Rocks, vol. i, pp. 187, 199, 1909.
310 G. W. Tyrrell—Tertiary Dykes
TABLE II.
iL PD) 3 4 5 6
SuOa wae : . | 60-46 | 58-67 | 61-69 | 64-13 | 59-59 | 59-86
Osta : -68 n.d. 1-00 1-19 Sri -66
‘Alp Ogee ; . | 14-85 | 14-37, |14=43 | 13-45. | 7S eioes
iHlea Oat oe ‘ 1) fee ibate) 1-64 1-23 1-08 3:33 2-86
FeO . | 5-82 6-94 5-86 6-31 2.13 3-56
MnO. : ‘ -10 trace -30 -O7 -18 +22
MgO 1-46 4-65 2-81 1-08 2-75 3-25
Ca O 8-19 7-39 4-97 3-62 5-80 6-3
Nay O 3-27 3-01 3-20 3-64 3-58 3-35
K,0 . | 2-20 1-42 1-72 2-32 2-04 1-62
FE Olabove 105° GO: 1-42) 2-36 2-71)
| | 9-02 || 1.96 1-08
Hy O atlos°G, ~ | -63) -25 -36)
Pst | i 05 = 94 aol 26 21
Bao >. ‘ ; a See ea! -09 zat -06
Che : : ‘ ae me -02 awe ae —
100-27 |100-11 |100-12 [100-26 |100-00 {100-02
1. Cumbraite, Tertiary N.W. dyke (interior glassy facies), II, 4. 3. 4. (tonalose),
is Herie Port, Great Cumbrae, Firth of Clyde. Anal. by Chetai Yu, Bose;
alkalies, Ti Oz and Ps Os, by A. Scott, M.A., D.Sc.
. “* Pitehstone ’’ (Cumbraite, Eskdale type), N.N.W. dyke with ‘‘ sheath-and
core ’’ structure, IT’, 4’. 3. 4. (tonalose), Eskdale, Dumfriesshire. Quoted
from Sir A. Geikie, ‘1880, p. 253.
3. Leidleite (glassy part of sill showing ‘* sheath-and-core’’ structure), II, 4.3.4.
(tonalose), 2 miles S.S.W. of Pennyghael, Mull. Anal. E. G. Radley,
Summ. Prog. Geol. Surv. for 1912 (1913), p. 69.
4. Inninmorite (inclined sheet, ‘‘ contains small phenocrysts of basic plagio-
clase, and has acicular augite in the glassy base’’), ‘II, 4. 2 (8). 4.
(tonalose-dacose),1 mile S.8.W. of Pennyghael, Mull. Anal. E.G. Radley,
Summ. Prog. Geol. Surv. for 1912 (1913), p. 69. For other analyses of -
er and inninmorite see H. M. Anderson and HE. G. Radley (1916,
p. 212
5. Average Andesite (Daly), ‘II, 4.3. 4. (tonalose). R. A. Daly, Igneows Rocks
and their Origin, 1914, p. 26.
6. Average hypersthene-andesite, II, 4. 3’. 4. (tonalose). Calculated from
71 analyses of rocks described as hypersthene-andesite, hypersthene-
augite-andesite, bronzite- and enstatite-porphyrite, enstatite-diabase-
porphyry, and bronzite-tholeiite; taken from Iddings, Igneous Rocks,
vol. ii, 1913 ; Iddings & Morley, paper on ‘‘ Japanese Volcanic Rocks ”’’,
Proc. Nat. Acad. Sci., Washington, vol. ii, 1916; MRosenbusch,
Gestemmslehre, 3rd ed., 1910; Washington, Prof. Paper 14, U.S. Geol.
Surv., 1903, ete.
Comparing the Cumbrae types with the related leidleite and
inninmorite of Mull, it may be noted first that the latter are richer
in combined water, and therefore in glass, than the Cumbrae types.
Leidleite differs otherwise in containing a smaller percentage of
lime, due probably to the absence of anorthite. This results in an
almost exact reversal of the proportions of diopside and hypersthene
in the norms of the two rocks (Table III, 1, 3), but otherwise the
bo
of the Clyde Area. 311
analyses and norms are very similar and give identical symbols in
the American Quantitative Classification. The analysis of innin-
morite shows much less lime and more silica, causing its norm to
have a more quartzose and alkalic character than that of the Cumbrae
type. This is reflected in the symbols for class and rang; and
inninmorite falls into the subrang dacose, but close to the border
between dacose and the neighbouring subrang ¢onalose, into which all
the other analyses fall.
TABLE III.
1 2 3 4 5 6
Quartz A . | 14:04 11°28 19°14 DB 15°48 15°54
Orthoclase . on la) S34 10°01 13°34 11°68 9°45
Albite . ; at Baca a 25°15 NLS 30°92 29°87 28°30
Anorthite : . | 19°46 21°41 19°74 12°51 25°58 26°41
Diopside é a | alReye) erat 3°00 enmiltes 1158383 3°59
Hypersthene . 3 3°14 16°52 13°96 10°19 8°25 9°80
Magnetite . : 1°62 2°32 1°86 1°62 4°87 4°18
Ilmenite : : 1337 — 1°98 2°28 1°52 Liz)
Apatite : } a — 51 67 “67 “34
Class faye stages JOE. “TOL. ADL, le
Order 4. AG 4, 4, 4, 4.
Rang 3. Bie Be 2 (3). 3. By.
Subrang 4, 4. Abs rae 4, 4,
Tonalose|Tonalose|Tonalose|Tonalose-|Tonalose|Tonalose
dacose |
Interesting points arise from the consideration of the analyses of
average andesite and average hypersthene-andesite. Comparing the
two, average hypersthene-andesite has slightly more ferrous iron,
magnesia, and lime, but less alkalies than the average andesite. ’
' Hence, the average hypersthene-andesite is slightly more femic and
more calcic than average andesite, as is well shown by the norms
and the magmatic symbols (Table III, 5, 6). Furthermore, both
averages show about 15 per cent of normative quartz, and fall into
the subrang tonalose (II, 4, 3,4). Rocks with analyses like these
should be regarded as dacites according to the classification adopted
by Iddings.. They would belong to varieties of his shastaite
(andesine-dacite),* transitional to bandaite (labradorite-dacite), devoid
of modal quartz. Most of the analyses in this group fall into the
subrang tonalose. ‘The rocks called ‘‘andesite’’ by petrographers
contain then, on an average, 15 per cent of normative quartz, which,
however, rarely appears in the mode, and must exist occult im a fine-
textured or glassy base. The term dacite should be restricted to
andesitic rocks so rich in excess silica that it appears as quartz in the
mode. The average dacite of Daly? has 25 per cent of normative
l Tgneous Rocks, vol. ii, p. 106, 1913.
2 Tbid., p. 111.
* Igneous Rocks and their Origin, 1914, p. 25.
312 G. W. Tyrrell—Tertiary Dykes
quartz and falls into the subrang Jassenose (I’, 4 (2). 3. 4, yellow-
stonose-lassenose). Furthermore, if the average hypersthene-andesite,
based on seventy-one analyses, be compared with the average hyper-
sthene-andesite computed by Daly on twenty analyses, it will be found
that the differences are quite insignificant. This testifies to the
distinctness and solidarity of this petrographic type, as distinguished
by many petrographers on the basis of mineral composition. There
can be little doubt but that a similar result would be arrived at for
many other rock-types.
RELATIONSHIPS AND NoMENCLATURE OF THE CUMBRAE TYPE.
It is very difficult to place this rock under the existing system of
nomenclature. Similar rocks from the North of England and else-
where have been called ‘‘augite-andesite”’, ‘‘basaltic andesite”
‘‘andesitic basalt”’, “‘andesitic dolerite’’, ‘“‘tholeiite’’, ‘‘ basalt’’,
etc., a list which sufficiently indicates the petrographers’ perplexity.
The rock can be regarded neither as a true andesite nor a true
basalt. In chemical composition 1t approaches the andesites; but if
the term andesite be limited (as it should be if used specifically) to
voleanic rocks with predominant andesine felspar, the Cumbrae rock
clearly does not fall within this group. Its mineralogical expression,
on the other hand, approaches that of a basalt; yet it cannot be
placed thereunder because its chemical composition, with 60 per cent
silica, is entirely unlike that of basalts. A similar difficulty of
nomenclature has been experienced with the related dykes of Mull,
and the Survey petrographers have solved the problem by giving the
rocks new locality names, such as leidleite and inninmorite. The
root of the difficulty is, of course, the abundant glass in the rock,
which, as has been shown, must contain the excess silica and alkalies
above that necessary to form the visible felspars. ‘The probable
mineral composition had the rock been holocrystalline is given
approximately by the norm. There would have been about 47 per
cent of a felspar near Ab, An, (andesine), about 21 per cent pyroxenes,
12 per cent orthoclase, and 14 per cent quartz, i.e. the rock would
have been a pyroxene-dacite; or, if the quartz had remained occult,
as 1t appears to do in most andesites, a pyroxene-andesite.
Terms such as dolerite, basalt, andesite, dacite, and the like, have
become far too comprehensive for a more discriminative petrography
than frequently employed. If they are to be retained as more than
mere field names, or comprehensive ‘‘omnibus’’ names, they should
be frankly used as group or generic terms, comprising numerous
sub-groups and species which should be given new names. Lacroix
has recently begun the discrimination and renaming of ultrabasic
forms of basalt and nepheline-basalt,' whilst Iddings has attempted to
distinguish the numerous varieties of dacite, andesite, and basalt,
according to their predominant felspar.”
If, however, nomenclature is based on mineral composition, there
will ‘always be a terminological difficulty with glassy rocks, for the
greater the amount of glass the more abnormal will be the constitution
1 A. Lacroix, Comptes Rendus, vol. elxiii, pp. 177-83, 213-19, 253-8, 1916.
2 J. P. Iddings, Igneows Rocks, vol. ii, pp. 106, 191, 1913.
of the Clyde Area. 313
of the crystalline residuum as compared with the possible holo-
crystalline development. Glassy rocks are probably best named in
such a way as to connect them with their nearest holocrystalline
equivalents, and consequently, for accurate naming, the chemical
composition will have to be determined in many cases. In general,
however, petrographers will only find this necessary when the rock
is of an abundant and widespread type not directly associated with
its holocrystalline equivalent, as is the case, for example, with the
rocks under discussion and the pitchstones of Arran.
The use of the dominant mineral constituents and texture as
qualifying terms, and of the prefix hyalo-, in naming glassy rocks,
results in some unwieldy designations, which may be illustrated as
follows :—
Cumbraite = Anorthite-enstatite-augite-hyaloandesite.
Inninmorite = Anorthite-(uniaxial) augite-hyaloandesite.
Leidleite = Subvariolitic-augite-hyaloandesite.
In such cases the short locality-names, such as those given above,
are much the more convenient for use when the rocks of a single
petrographic province are being described, and for the Cumbrae rock
I therefore propose the term cumbraite, which is defined according to
the mineralogical and chemical composition given above. A new
name should only be given to a glassy rock when it is an abundant,
widespread, and homogeneous type, different either mineralogically
or chemically from previously described glassy rocks, not when it is
a mere hyaline facies of an associated holocrystalline rock. Whether
these terms should obtain a circulation outside the discussion of the
British Tertiary petrographic province is a question beyond the scope
of this paper. My own opinion is that they should not, unless
future work should show that they are widespread types in other
petrographical periods and provinces.
OrHER OccURRENCES OF CUMBRAITE.
Two dykes closely resembling the typical cumbraite occur on
the Ayrshire mainland. One forms a N.W. dyke, 5 miles long,
eutting across the River Ayr and its tributary the Coyle Water, near
Sundrum House, about 6 miles east of Ayr. This rock is somewhat
decomposed, but the anorthite phenocrysts remain fresh, and the
enstatite is clearly recognizable by its pseudomorphs. ‘he other
occurrence is in the Burnock Water near Ochiltree, and appears to be
quite a short dyke. In thin section this rock is seen to contain
rather less glass than the typical cumbraite, and is richer in felspar
and pyroxenes, especially the latter, thus providing a transition to
the true tholeiites. ‘The enstatite is pseudomorphed by a green
fibrous mineral,
In the Cowal peninsula of Argyllshire a perfectly typical cumbraite
occurs at Toward (Clough, 1897, pp. 131-2, 136). This dyke is
said to have a glossy band in the interior, running parallel with
the length of the dyke, a feature connecting it with the Eerie Port
dyke of the Cumbrae. A slightly different type which may, however,
1 Iam obliged to the Geological Survey for the loan of the Cowal slides on
which these remarks are based, and also for the Eskdalemuir slides.
ot
314 G. W. Tyrrell—Tertiary Dykes of the Clyde Area.
still be referred to cumbraite, occurs near Cruach Chuilceachan, in
Cowal. This rock has been described by SirJ. J. H. Teall (in Clough,
1897, p. 155). It shows reticulations and bandings of varieties
differing in texture and amount of glass. It carries glomero-
porphyritic groups of basic felspar and hypersthene in a richly glassy
groundmass containing microlitic felspar and augite.
The great Eskdalemuir (Dumfriesshire) dyke described by Sir A.
Geikie (1880, pp. 219-55; 1897, vol. i1, pp. 183 et seqq.) forms
a distinct variety of cumbraite distinguished texturally from the
Cumbrae rocks. In the latter both the felspars and pyroxenes of
the groundmass are slender and elongated, and may show a tendency
to subvariolitic groupings, as also in the leidleite and inninmorite of
Mull. In the Eskdalemuir type (Fig. 15) the felspars are much
broader, giving almost square or rhomboidal outlines, and the augite
tends to form small clusters of minute, granular, equidimensional
crystals. The enstatite stands out, however, as somewhat larger
prismatic crystals. The abundant glass is yellow and comparatively
free from microlites. Further differences are the comparative
paucity of the large phenocrysts of anorthite, and the presence of
sharply crystallized and uniformly distributed grains of magnetite in
the Eskdalemuir type. Sir A. Geikie has noted the occurrence of
curious enclosures of almost or quite holocrystalline material
consisting mainly of granular augite and felspar laths. The
‘‘sheath-and-core’’ structure, of which this rock presents the type,
must also be mentioned, as it appears, more or less perfectly, in
many of the rocks treated in this paper. This rock may be
distinguished as the Eskdalemuir type of cumbraite. The contrast
between the textures of the two types is shown by Figs. la and 16
(see also Teall, 1888, pl. xiv, fig. 1).
Rocks probably belonging to the Eskdalemuir type occur in the
four great W.N.W. dykes which traverse the Muirkirk district
of Ayrshire, the most southerly of which is the continuation of the
Eskdalemuir dyke. Enstatite, however, is not so abundant in these
dykes as in those described above, and is always represented by green
pseudomorphs. Furthermore, the anorthite phenocrysts are both
small and sparse, and may be locally absent. The yellow glass of the
groundmass provides abundant quartz on its devitrification.
At least two dykes in the Cowal area belong to the Eskdalemuir
type and show the ‘‘sheath-and-core”’ structure, as described by
Clough (1897, pp. 185, 142). The Cruach Mhor dyke carries
a considerable amount of enstatite in small prisms. The dyke near
Brackleymore School shows enstatite in central intergrowth with
augite, but frequently decomposed to a fibrous green mineral
of straight extinction. A dyke from the burn half a mile west
of Loch na Leirg, Whiting Bay, Arran, possesses affinities with
this type. .
Typical cumbraites have not yet been found in Arran, but rocks
which may represent an almost holocrystalline development of the
_ cumbraite magma occur as north-west dykes penetrating the great
sill of teschenite or crinanite at Dippin (Tyrrell, 1916, pp. 193-6).
These rocks carry a few small phenocrysts of bytownite, frequently
é
{
Notices of Memoirs—The Oulfields of Egypt. re)
worn and corroded, with prisms of enstatite and augite, in a ground-
mass of labradorite laths, augite, and iron-ore granules. The base,
which may represent a devitrified glass, now consists of an ill-
defined, turbid, untwinned, felspathic substance and quartz, which
carries numerous microlites of iron-ores. The rock is fully described
in the above-cited paper. A N.N.W. dyke with similar characters
occurs in the Church Burn at Corrie.
The dykes of the cumbraite facies, therefore, are distributed in
a narrow band running §8.8.E. from the Cowal peninsula, through
the Great Cumbrae, down into central Ayrshire; and thence with
a more south-easterly trend through the Muirkirk district towards
the Scottish border. South of the border they give place to dykes
which are regarded as basic varieties of imninmorite (Cleveland
dyke) and the Brunton type of tholeiite (Anderson & Radley, 1916,
p. 209). The cumbraites appear to belong to the regional or solitary
dykes of Sir A. Geikie; and this may be the reason for their non-
appearance in Arran, where the dykes are local and connected with
the Arran centre of Tertiary eruption.
(To be concludéd in the August Number.)
NOTICES OF MEHMOTRS.-
————
I.—Tse Orrietps or Eeyrrr.!
ETWEEN the Sinai Mountains and the Red Sea Hills lies
a depressed area bounded by faults and traversed by three hill-
ranges, the Esh Mellaha, Zeit, and Araka Hills, which are separated
from each other and from the main ranges by three plains and the
Gulf of Suez. All these features trend approximately north-west
and south-east. The breadth of the sunken tract is on the average
100 kilometres, of which the Gulf occupies about one-fourth. |
Although petroleum has only been found in quantity in the
peninsula of Jemsa, near the entrance to the Gulf, and at Rarquada?
about 50 kilometres to the south-east of Jemsa, near the shore of
the Red Sea, the whole of the area, together with a narrow strip on
the shore of the Red Sea, extending as far as Ras Benas, is
characterized by great geological similarity, and may be referred to
as the oilfield region; but the district more especially dealt with in
this report lies between 27° 10’ and 28° 10’ North lat., and 38° and
33° 50’ Kast long. A coloured geological map of this area anda plate of
ten horizontal sections accompany the Report. During the progress
of the work, extending over several years, the author examined some
of the Roumanian oilfields under the guidance of Professor Mrazec,
who subsequently visited Egypt and to whom we are mainly indebted
for the horizontal sections.
Those portions of the Report which deal with the tectonic features
of the oilfield region have recently been summarized by the author
1 Report on the Oilfields Region of Egypt, by W. F. Hume, D.Sc., A.R.S.M.,
F.R.S.H., Director Geological Survey of Hgypt. pp. viii and 103, with
a geological map (1: 150,000) from surveys by John Ball, Ph.D., D.Sc., F.G.S.,
23 plates, and 9 text-figures. Cairo: Government Press, 1916. Price 30 P.T.
* Rarquada is opposite Gefatin Island
316 Notices of Memoirs—The Oulfields of Egypt.
himself in the Gxorocicat Macaztne,! so that it will be unnecessary
in this notice to go into that branch of the subject in any detail.
In dealing with the succession of deposits the author follows the
Lyellian method, beginning with the most recent. In this brief
summary we will reverse the process, though we do not wish to
suggest that this method should have been followed in the Report.
The oldest rocks consist of granite and of ancient volcanic and
sedimentary rocks, similar to those of the Red Sea Hills and the Sinai
Mountains, probably of Archean, certainly of pre-Carboniferous age.
They form the cores of the asymmetric anticlines of the Esh Mellaha,
Zeit, and Araba Hills as described by Dr. Hume in the paper already
referred to. On the old floor formed of these rocks were deposited
Nubian Sandstone, Cretaceous and Eocene strata. The succession is
the same as that occurring on the western side of the Red Sea Hills
and in Sinai, except that in the latter locality flat-bedded Carboni-
ferous strata intervene between the old floor and the Nubian
Sandstone.? The Cretaceous and Eocene rocks are seen only in the
hill ranges where their thickness is often greatly reduced by folding.
Their presence confirms the view generally held that these rocks
were originally continuous over the whole area.
The Miocene rocks which follow rest on any of the underlying
series. Thus on Shadwan Island they rest on granite and in the
Zeit range on Lower Cretaceous strata. In the Esh Mellaha range,
some 20 kilometres to the west of the Zeit range, both the uppermost
Cretaceous and the Kocene rocks are present. It follows, therefore,
that the Gulf of Suez marks the position of the axis of a post-Eocene
and pre-Miocene anticline from which the sediment overlying the
granite must have been wholly or partially removed by denudation
before the Miocene rocks were deposited. We may remark in passing
that in other parts of Egypt this interval is represented, to some
extent at least, by the so-called petrified forests, the fluvio-marine
series of the Fayum, and other deposits of a continental type.
Flint conglomerates and coral reefs occur at the base of the
Miocene. In the Zeit range conglomerates, resting on Cretaceous
strata, are immediately followed by a dark limestone containing
fossils which M. Fourtau has identified with forms ‘typical of the
Lower Miocene (Burdigalian) and of the Lower Helvetian (Lower
Middle Miocene)’’. The limestone is succeeded by an important
series of Globigerina marls with Aturia aturi, Terebratula miocenica,
and a delicate Pecten fauna. Similar marls have been met with in
a boring at Rarquada between 1,169 and 1,181 feet where they are
underlaid by a limestone and a flint conglomerate, as in the Zeit
range. his boring terminated in sands which Dr. Hume identifies
with the Nubian Sandstone. The sands yielded oil. ‘These fossili-
ferous strata are succeeded by deposits of clay, gypsum often
calcareous, dolomitic limestones and salt; their total thickness cannot
1 “*Some Notes on the Post-Eocene and Post-Miocene Movements in the
Oilfield Region of Egypt’’: Grou. MaG., January, 1917, pp. 5-9. The map
illustrating this paper should be referred to.
2 See review of Dr. Ball’s memoir on The Geography and Geology of West-
Central Sinai, GEOL. MaG., February, 1917.
Notices of Memoirs—The Oilfields of Egypt. 317
be less than 3,000 and may be as much as 6,000 feet. Above this
great saliferous formation, which is generally unfossiliferous, occur
oyster beds containing Ostrea virlety and an oyster of the crassissima
type. Pending amore detailed examination of the paleontological
evidence the beds from the flint-conglomerate up to and including the
oyster beds are grouped together as being of Plio-Miocene age. They
all belong to the Mediterranean area and can be connected up to the
north with the Miocene deposits which occur between Suez and
Cairo.
The oyster-beds are followed by strata containing the remains of
sea-urchins and Pectens now living in the Red Sea and Indian Ocean,
together with some forms which are apparently extinct. These
deposits are referred to as Plio-Pleistocene. They mark the invasion
of what had hitherto been a southward extension of the Medi-
terranean province by Erythrean forms of life. The plains are
largely covered by thick deposits of gravel, derived from the waste
of the hills. These are classed as recent, together with a raised
beach of corals and molluses now living in the Red Sea. The beach
forms a marked feature on the Zeit and Jemsa coast at an average
height of 15 metres.
Let us now consider the great saliferous formation, with which
the oil appears to be associated, in greater detail. Gypsum is the
most prominent rock atthe surface. Salt in thick beds is only known
from the borings. The gypsum is interbedded with clays or marls,
and in some places, as in the Jemsa peninsula, with dolomitic lime-
stone. Vertical sections of four borings are given. ‘They show
remarkable changes within short distances. Bore 11 passed through
alternations of gypsum and clays to a depth of about 500 feet ;
then through thick beds of salt, separated by thin beds of clay,
limestone, and gypsum, to a depth of 2,650 feet, where it ended in
salt. The total thickness of salt in this section was found to be
about 1,900 feet, or 600 metres. Bore 1, which was apparently
situated about one kilometre from Bore 11, is represented as being
entirely in limestone. It reached a depth of 1,300 feet. The other
two bores, less than 300 metres from Bore 1, were in gypsum, with
thin beds of clay and limestone. Speaking of the Jemsa oilfield,
Dr. Hume says: ‘‘Sections have been made of the area so as to
include the bore-profiles, but efforts to explain the present conditions
either as simple anticlines or synclines have ended in complete
failure. There is a provoking horizontality in the strata of the
eastern hill of Jemsa, immediately above the oil-belt on the east
coast. . . . What we do know is that the Jemsa borings which have
yielded profitable oil occupy a long thin band close to the sea,
parallel to the general fold movement of the country.”
The oil at Jemsa appears to have been obtained from the dolomitic
limestone which is porous, and therefore likely to form a good
reservoir rock. Fragments of a similar limestone are common on
the surface of the gypsum throughout the oilfieldregion. Dr. Hume
suggests that this feature, and also the great thickness of limestone
met with in some of the borings, may be due to the removal of
gypsum in solution from beds containing both carbonate and sulphate
318 Notices of Memows—The Orlfields of Egypt.
of lime. Mr. Lucas contributes a chapter on the solubilities of these
two substances in water and saline solutions, in which he shows that
the relative solubility of gypsum increases up to a certain point as
the salinity increases; and Dr. Hume points out that the under-
ground waters at Jemsa have approximately the composition most
favourable for the solution of gypsum. There appears to be strong
reason for believing that the circulation of water in the saliferous
formation has brought about great changes in the nature and distri-
bution of the original materials.
Salt which has been met with in several bores does not occur in
one central core as in the Roumanian fields, but is interstratified
with shales and gypsum. It is best developed in the minor anti-
-clines, and ‘‘ Professor Mrazec was strongly impressed with the idea
that these strata [the salt-beds] were derived by a leading action
from salty clays, similar to those well developed at the surface,
whereas beds of salt have never been noted on the large scale in the
above ground observations”’. Dr. Hume suggests that the saliferous
deposits were formed in a slowly sinking area into which sea-water
could gain access, that the evaporation over this area was sufficient
to cause the precipitation of gypsum and salt, and that while this
was going on streams were bringing down clay and calcareous
matter from the surrounding land.
The similarity in many respects of this formation to that of the
Roumanian oilfields is referred to. May we not extend the
correlation? Aturia aturi is a characteristic fossil of the ‘‘ Schlier”’
which, according to Suess! and others, includes the Carpathian salt-
beds, and probably also those of Armenia and Azerbigan, of the
Iranian tableland as far as Khorasan, of the valley of the Tigris,
and of the coast of the Persian Gulf. Doubt may exist as to the
precise correlation of all these saliferous formations which, as Suess
says, ‘‘afford us the spectacle of a great expiring sea’”’; but it seems
clear that, both as regards age and mode of formation, the deposits of
the Egyptian oilfield are closely allied to them ; and it is with them
that some of the most important oilfields of the world are intimately
associated.
No definite opinion is expressed as to the origin of the petroleum,
but the porous limestone (Jemsa) and the Nubian Sandstone
(Rarquada) are regarded as reservoir rocks. Indications of oil
are most conspicuous on both sides of the Gulf of Suez, and as the
overfolding of the anticlines is directed towards the Gulf, it is
suggested that the post-Miocene stresses probably reached their
greatest intensity in this region, and may therefore have forced the
oil into any rocks in the neighbourhood capable of containing it.
No detailed records of bores are given, except the four at Jemsa,
and no statistics of production. It is to be regretted that so much
secrecy should be considered necessary by those engaged in controlling
and developing the economical resources of a country, and very
doubtful whether it is not carried much further than is required for
commercial purposes. Rivals generally find out sufficient for their
purpose, and the progress of science is, therefore, often unnecessarily
1 Face of the Earth, vol. i, p. 309, English translation.
a
thE
a
Notices of Memoirs—The Oilfields of Egypt. 319
retarded. Moreover, valuable information may be, and often is, lost.
Wherever Governments grant facilities for exploration by deep bores
they should see that accurate records are kept and made public after’
a reasonable lapse of time.
The two outstanding features which sharply differentiate the oil-
field region from the plateau regions of Sinai and Egypt are the
presence (1) of a thick series of Miocene rocks belonging to the
Mediterranean area, and (2) of sharp folding due to tangential
pressure. We repeat the question that we put in reviewing
Dr. Ball’s memoir on West Central Sinai. Did the Miocene sea
advance over a planed down surface of the older rocks? It was
at one time supposed that some at least of the faulting in the region
between Suez and Cairo was of post-Eocene and pre-Miocene date,
and that Miocene rocks had been deposited against ‘‘ horsts”’ of
Kocene limestone. That view was disproved by Barron,’ who showed
that they were superposed upon, not apposed against, the Eocene
strata, and that no evidence of pre-Miocene faulting was to be found
in that district. Now Dr. Hume comes forward with evidence that
the Miocene rocks of the oilfield region were formed over the
denuded arch of the great post-Kocene fold whose axis coincided
approximately with what is now the Gulf of Suez. Although we
are not able to define with precision the boundaries of this southward
extension of the Miocene sea there is some evidence to show that it
did not extend far beyond the faults which bound the sunken tract
on the east and on the west, and, therefore, as Dr. Hume points out,
that it found a gulf agreeing approximately in position and direction
with this tract and its continuation in the Red Sea trough. But in
any case there must have been a considerable geocratic movement
in post-Miocene times, for Dr. Ball has shown that Miocene rocks
occur at a height of 642 metres on Sarbut el Gamal? in West Central
Sinai, and has estimated the throw of the post-Miocene faults in
that region at about 2,000 metres. Kven allowing for the possibility
that this may be an over-estimate, there seems no escape from the
conclusion that the oilfield region owes its position largely to
subsidence along faults of later date than the Miocene rocks of the
district. But we must await the more precise determination of the
paleontological horizons before attempting to correlate the physical
history of the oilfield region with that of the Mediterranean area to
which it belonged until it was invaded by the Erythrean fauna in
comparatively recent times.
It is interesting to compare the views of Suess as to the structure
of the district with those set forth in this memoir and in other
publications of the Egyptian Geological Survey. In his chapter on
the Great Desert Plateau Suess shows that flat-bedding in the
Cretaceous and Yertiary rocks is the characteristic feature of large
portions of North Africa south of the Atlas range, of the Sinai
peninsula, of North and South Arabia, of Palestine and Syria, and
that the same feature probably extends as far east as the Persian
1 The Topography and Geology of the District between Cairo and Suez,
Cairo, 1907, p. 55.
2 See GEOL. Maa., February, 1917, p. 83.
320 Notices of Memoirs—fh. Bullen Newton—
Gulf. The only post-Tertiary movements that he recognizes over
this vast area, extending eastwards from the Atlantic Ocean for
some 3,000 miles, are ‘‘in the form of subsidence, particularly as
great trough-subsidences, which are here and there associated with
flexure of the edges. On the other hand, tangential movement and
folding are entirely absent, at least as far as we can judge at present’’.
This view can no longer be maintained if we are to understand by
‘¢ subsidence ’’ movements along normal faults. Flat-bedding, so far
as the eye can judge, certainly is the dominant feature in the
Egyptian portion of the Nile Valley, in the Oases, and in Sinai.
But, as Dr. Hume has pointed out,! the V-shaped outcrops on the
geological map of Egypt require the assumption of a broad syncline
whose axis dips slightly to the north, while the relations of the
Cretaceous and Kocene rocks to the Red Sea Hills and Sinai Mountains
indicate the presence of a complementary anticline to the east. Thus
folds of great amplitude certainly occur in this portion of the desert
plateau, reminding one of the swell of the ocean which is often felt
far away from the storm centre which produces it. Now Dr. Hume
shows us that sharp folding due to tangential pressure is also present.
But this alone would probably not have led Suess to modify his
general view. He would doubtless have regarded it as connected
with a trough subsidence and therefore of only local importance.
The Report is well illustrated by photographs of scenery and
figures of the more characteristic fossils which are briefly described
by M. Fourtau in a special chapter. It does not profess to be final.
The map is said to be provisional and research is still going on. We
await with interest the communications which are to follow, and
conclude by wishing success to those who are engaged in developing
the Egyptian oilfield, to whom we are indebted, both directly and
indirectly, for so much geological information about this most
interesting region.
Ae esta 4b
I].—Tuar ConcnotoeicaL Features oF THE LENHAM SANDSTONES OF
Kent, AND THEIR STRATIGRAPHICAL ImPporTANCE. By R. Buiien
Nrwron, F.G.S8., of the British Museum (Natural History).
Parr II.
CoNncLUSIONS.
W* gather from the previous literature on this subject that
the majority of investigators have agreed that the Lenham
Beds are equivalent to the Diestian deposits of Belgium, which
have been generally recognized by geologists as belonging to
the base of the Pliocene system, on account of the shell remains
exhibiting a marked Miocene facies with many species identical or
related to southern or Mediterranean forms. The Miocene aspect of
the Lenham fauna is very pronounced, as out of the seventy-seven
conchological species that have been determined in the present work,
forty-seven, or sixty per cent, date their origin from the Vindobonian
! Explanatory notes to accompany the geological map of Egypt.
The Lenhum Sandstones of Kent. 321
(Helvetian—Tortonian) stage, which represents the middle part of that
epoch in such countries as Germany, Italy, France (S.), Holland,
Denmark, and Austria (Vienna Basin). Again, twenty-six of the
Lenham species occur as well in the Redonian beds of Gourbesville,
Normandy, which are either of Vindobonian or Messinian age, and
therefore Miocene. These Gourbesville deposits are of peculiar
interest. ‘They were originally discovered by Vasseur,' and ascribed
to Pliocene or Red Crag times, having been more critically studied
since by M. G. F. Dollfus,? who in 1880 regarded them as of similar
age, although subsequently determining them as belonging to his3
‘tage, Rédonien’”’, which in explanation was stated to be neither
Helvetian nor Plaisancian, but equivalent in time to the Tortonian
stage of the Miocene, notwithstanding that he had previously
paralleled this new horizon with the Anversian Beds of Belgium.‘
The Redonian fauna was considered to be related to the Gedgrayian
(Coralline Crag) of England.
About twenty of the Lenham shells, including Anadara diluvit,
occur in the Upper and Middle Miocene of Holland, and a rather
smaller number of species in the same horizons of Denmark, as
determined by Molengraaff and Van Waterschoot Van der Gracht®
for Holland and by Ravn® for Denmark. The Pelecypod, Anadara
diluvit, is of frequent occurrence in the Lenham Beds, and although
unknown in the Diestian of Belgium, it is found in the Bolderian .
(= Tortonian) and Anversian (= Messinian) of that country, as well
as in the Vindobonian of Germany, France, Austria, and Italy, and
in the Plaisancian deposits of Italy and France; its only British ~
occurrence from the Lenham sandstones was first recorded by Mr. Reid.
The Lenham fauna presents an interesting resemblance to that of the
Upper Miocene of North Germany (Reinbeck and Holstein), described
by Zimmermann’ and Gottsche,* and regarded as Messinian or the
latest stage of the Miocene period, a formation-term introduced by
Mayer-Eymar,’ to include Pontian—Sarmatian, Zanclean, and Miocene
-of other authors. The North German Miocene deposits contain
twenty-five species of Mollusca which are also found in the Lenham
Beds, among them being Streptochetus sexcostatus, Zaria subangulata,
Tellina benedent, Papillicardium papillosum, ete.
Speaking further of this Miocene facies of the fauna, it may be
observed that Drillia obeliscus and Clavatula jouanneti are first known
in Burdigalian times, whereas Margaritifera phalenacea commenced
its career in the Aquitanian stage, which forms the basal or oldest
1 Bull. Soc. Géol. France, ser. II, vol. vii, p. 741, 1879.
2 Bull. Soe. Géol. Normandie, 1880.
* Assoc. Francaise-Cherbourg, 1905, published 1906, pp. 358-70.
+ Bull. Soc. Géol. France, ser. Iv, vol. iii, p. 258, 1903.
® “‘Niederlande’’: Handb. Region. Geol., vol. i, pt. iii, p. 53, 1913.
® **Molluskfaunaen I Jyllands Tertiaeraflejringer, etc.’?: Mus. Min. Géol.
Univ. Copenhague: Paléontologiques, No. 7, 1907 (plates and text).
7 “* Teber der Schichten der Tertiarformation welche bei Reinbeck durch die
Hamburg, etc.’’: Amtl. Ber. Deutsch. Nat. Aerz. Kiel (1846), 1847, pp. 232-4.
® Die Mollusken-Fauna des Holsteiner Gesteins’’: Abhandl. Geb. Nat. Ver.
Hamburg, vol. x, No..8, pp. 14, 1887.
® Cat. Syst. Foss. Tert. Mus. Zurich, 1867, pt. ii, p. 13.
DECADE VI.—VOL. IV.—NO. VII. All
322 Notices of Memorirs—R. Bullen Newton—
division of the Miocene formation. The following Gastropods may
also be referred to as dating from the Vindobonian stage of the
Miocene; Streptochetus sexcostatus, also Messinian and Anversian ;
Bonellitia serrata, ranging into the Italian Plaisancian ; Zerebra acu-
minata, occurring also in the Messinian of North Germany, the
Anversian of Belgium, and in the Plaisancian and Astian beds of
Italy ; Maculopeplum lamberti, recorded as well from the Redonian
of France, the Diestian and Scaldisian of Belgium, the Box-stones
and the Coralline and Red Crags of England; and Ficus reticulata
known also from the Redonian of France, the Messinian of North
Germany, the Bolderian, Anversian, and Diestian of Belgium, Box-
stones, Lenham Beds, and Coralline Crag of Britain, Plaisancian and
Astian of France and Italy, and belonging also to recent seas. Among
the chief Pelecypods similarly originating in Vindobonian times are:
Glans senilis, known also in the Redonian, Scaldisian, and Coralline
Crag; Arcopagia ventricosa, also Plaisancian and Astian; Tellin
beneilent, Messinian and from Bolderian to Scaldisian; Plagiocardium
hirsutum, Plaisancian and Astian; Astarte basteroti, Redonian, Dies-
tian, and Scaldisian; Papillicardium papillosum, Messinian, Redonian,
St. Erth Beds, Plaisancian and Astian torecentseas; Cyprina rustica,
Messinian, Anversian to Scaldisian, Box-stones, and Coralline Crag;
Cyrtodaria angusta, Messinian, Bolderian to Scaldisian, Box-stones,
and Coralline Crag; and Panopea menardi, Anversian, Messinian,
Box-stones, Coralline and Red Crags.
The only representative of the Brachiopod group of shells is Zere-
bratula perforata, which ranges through the Redonian of France,
Bolderian to Scaldisian of Belgium, and the Coralline and Red Crags
of Britain. With the exception of Meus reticulata and Papill-
cardium papillosum, which exist in present seas, the species thus
enumerated are extinct. Several of the Lenham species occur in the
Bolderian and Anversian beds of Belgium, the latter according to
M. Dollfus! being Vindobonian, and equivalent to his Redonian stage,
although attributed by Renevier” to the later Pontian (= Messinian)
division of the Miocene. The Anversian and Diestian occurrences
represent 34 and 30 species respectively, Box-stones 12, St..Erth 15,
and the Coralline Crag 50. It has been urged by Mr. Harmer that
the Coralline Crag fauna is younger than that occurring in the
Lenham deposits because several of the older shells found there and
that have been previously alluded to are absent in the Coralline Crag
beds, a fact more or less accurate, although some important forms
do occur in those deposits, such, for instance, as Margaritifera
phalenacea, Glans senilis, Cyrtodaria angusta, Panopea menardi,
Terebratula perforata, etc.
All these facts seem to suggest that the Lenham and Coralline
Crag faunas, although showing certain differences of detail, are,
nevertheless, to be regarded as presenting a close relationship, and
therefore to be considered as of approximately the same age. Marked
affinities are also noticeable in the molluscan faunas of the Coralline
1 Bull. Soc. Géol. France, ser. IV, vol. iii, pp. 256-60, 1903.
2
2 “‘Chronographie Géol.—Text Explicatif’’: Comp. Rend. Cong. Géol.
Internat. (1894), 1897, p. 597.
The Lenham Sandstones of Kent. 323
Crag and the Diestian beds of Belgium. This is apparent from
Mr. Harmer’s list of the Diestian species (Quart. Journ. Geol. Soc.,
1898, vol. liv, p. 317), in which, out of rather more than seventy
forms enumerated, nearly all are stated to oceur in the Coralline Crag.
- A considerable proportion of the Anversian species of Belgium, as
listed by M. Van den Broeck (Ann. Soc. Mal. Belgique, 1874, vol. ix,
pp. 118-121), likewise occur in the Coralline Crag, as out of a list of
175 species 80 are recognized as being found in that formation.
The following table shows the numerical representation of the
seventy-seven Lenham species occurring in the principal formations :—
Recent j : ‘ é . ; 40 species.
' Post-Pliocene . 4 : 5 ies 23 i
Astian 5 - i 5 : : 36 ae
Plaisancian ‘ P F : ‘ 40 ,,
_ Sealdisian . : d 3 : : 44,
Norwich Crag . \ j : : ea
Red Crag . 48 ,,
(probably derived from Coralline ee
Coralline Crag . Hl) op
St. Erth . ; : : i 4 Ghee
Box-stones. : ; : ‘ ; 13 af
Diestian . i : d ; j BOM eae
Anyersian . ‘ : ; 4 : Bb nn
Messinian . 3 : HON ‘ Doles.
Bolderian . : F 3 pies Reel G7 Aalaaiar
Redonian (Tortonian) . ; : 26y an
Vindobonian (Helvetian— —Tortonian) ‘ AM ces
The so-called Older Plocene beds of Mr. Reid’s memoir are
characterized by shells with a southern facies indicating warmer
climatic conditions than prevailed in the Red Crag period, when
boreal and Arctic species were largely predominant. The East
Anglian Box-stone deposits have been regarded by Mr. Harmer? as
the probable equivalent in time of the Waenrode Beds of Belgium,
which Wan den Broeck* has considered to be of Bolderian age and
therefore Miocene. In this connexion it is interesting to note that
the Box-stone beds have been quite recently regarded as Miocene by
Mr. Reid.’
Sir Ray Lankester* determined some Proboscidean remains from
those beds as a new species of Mastodon, although subsequently
recognizing them as a variety of J. angustidens of Cuvier,® being
further of opinion that they were older than the Diestian of
Belgium. It is well known that Cuvier’s species characterizes the
older Vindobonian beds of France, and is frequently found in the
ossiferous deposits of Sansan. When the Box-stone Mollusca are
more studied, such an age as is here indicated will probably be more
conclusively proved; in the meantime the evidence is in favour of
those deposits being older than the Lenham Sandstones. The St. Erth
deposits of Cornwall were originally described by Searles Wood ® as
1 Quart. Journ. Geol. Soc., vol. lvi, p. 708, 1900.
2 Ann. Soe. R. Mal. Belgique, vol. xix, pp. lvi-lzvi, 1884.
> Mededeel. Rijks. Delfst., 1915, No. 6, p. 9.
* Quart. Journ. Geol. Soc., vol. xxvi, pp. 507-9, 1870.
> GEOL. MaG., 1899, p. 292.
° Quart. Journ. Geol. Soc., vol. xli, pp. 65-73, 1885.
324 Notices of Memoirs—R. Bullen Newton—
of Red Crag age, although he observed that ‘‘the character of the
mollusea, as a whole, is essentially southern, no peculiarly Arctic
shell having as yet occurred”’.
The fauna was more particularly described by Professor Kendall
and R. G. Bell' in the following year and again referred to as con-
temporary with that of the Red Crag, a result contrary to the views
of Mr. Reid, who claimed a greater age. Since that discussion
Mr. Alfred Bell? has published a paper on the St. Erth Mollusca and
regarded their age as Mio-Plocene or Messinian, a somewhat similar
horizon having already been partially suggested by Gwyn. Jeffreys,
who stated: ‘‘ He was not clear whether the St. Erth deposit was of
Older Pliocene or possibly of Upper Miocene age.’’ In the same
paper Mr. A. Bell placed upon record an important opinion he had
received from M. Dollfus, which reads as follows: ‘‘ You have in
St. Erth exactly the same Pliocene fauna as we have at Gourbesville
in the Cotentin,’’ a statement more or less confirming the previous
researches of Mr. Reid (1890), who had acknowledged the necessity
of a strict comparison between the molluscan species of Gourbesville
and those of the St. Erth deposits, as the fossils from the former
locality ‘‘ point to conditions very similar to those indicated by the
shells from St. Erth”. The Gourbesville fauna, however, as
previously mentioned, is now considered to be of Miocene age
(Tortonian or Messinian). About fifty per cent of the Lenham shells
are extinct species, a somewhat similar percentage marks the Box-
stone fauna (according to a calculation made from Mr. A. Bell’s
memoir in Journ. Ipswich Field Club, vol. iii, pp. 7, 8, 1911), and
Mr. Reid (Survey Memoir, 1900, p. 64) has stated that the Coralline
Crag and St. Erth deposits contain each about forty per cent of
extinct shells. It will be observed that there is a similarity running
through these percentages of extinct forms, which appears to furnish
satisfactory evidence for regarding the four stages of Mr. Reid’s
‘‘Older Pliocene” group as of the same approximate geological age,
although the Box-stones, as before explained, may be somewhat older.
From the foregoing details of the different faunas involved in this
discussion, it is certain that many of the species had their origin in
Miocene times. ‘There is good reason for recognizing the St. Erth
shells as of Miocene age, because of their relationship to species
characterizing the French Redonian. Similarly, the Box-stone fossils
would belong to the same period, as their affinities are with those of
the Bolderian of Belgium, which is generally regarded as Tortonian
or Upper Vindobonian.
Lastly, the Lenham fauna with its strong Vindobonian and Coralline
Crag facies should also be placed in the Miocene, and in consideration
of its relationship to that characterizing the Upper Miocene deposits
of Northern Germany and the Anversian beds of Belgium, I would
recognize it as belonging to the latest or Messinian stage of the
Miocene, which is synonymous with the term Mio-Pliocene. The
stratigraphical name of Mio-Pliocene was introduced into Belgian
1 Quart. Journ. Geol. Soc., vol. xlii, pp. 201-14, 1886.
2 Trans. Roy. Geol. Soe. Cornwall, vol. xii, p. 133, 1898.
3 Quart. Journ. Geol. Soc., vol. xli, p. 72, 1885.
The Lenham Sandstones of Kent. Nay AS)
geology by Mourlon,’ who regarded it as including Lyell’s ‘‘ Upper
Miocene”’ and Dumont’s ‘‘ Pliocéne Diestien”’. It was recognized as
comprising two divisions or zones, the first characterized by Panopea
menardt, and the second by Glycymeris [ Pectuneulus| pilosa, both of
which are now included in the Anversian stage, or ‘‘ Crag Noir’’, of
the Belgian Miocene, which is developed at Edeghem and Antwerp.
These two Pelecypods occur in the Vindobonian strata of Europe,
P. menardi being found as well in the Lenham Beds, Box-stones, and
Coralline Crag beds, whereas Glycymeris pilosa is found present in
the same horizons, being likewise a member of the St. Erth fauna.
Although acknowledging certain differences in the faunas of these
Upper Tertiary horizons, which may be probably accounted for by
different conditions of environment, no great disparity of time need
be allowed for in considering their geological age. I am induced,
therefore, from a knowledge of their conchology, to regard the
Coralline Crag,” the St. Erth Beds, and the Lenham Beds of Britain,
together with the Diestian and the Anversian of Belgium, as of
Upper Miocene age, and belonging to the stage Messinian or Mio-
Pliocene, while the Box- ince or Nodule beds of Kast Anglia,
I should consider as referable to the Vindobonian division of the
Middle Miocene.
In accordance with these views, therefore, the following synopsis
of the various geological horizons referred to is now proposed :—
Recent : : : ; f : . British and Mediterranean Seas.
Post-Pliocene . Glacial, etc.
Norwich Crag.
Pliocene. .>) Red Crag (= = Astian of Utaly and | Britain.
Scaldisian of Belgium)
Coralline Crag . : : 4 oy)
aye Diestian . i : y : . Belgium.
pope cere °F | St. Erth Beds (Cornwall)
Lenham Sandstones
= Pontian or : «“ » ; y
Feta ) Anversian (= ‘‘ Crag Noir of cee a Belgium.
and Antwerp) . :
2 ll Britain.
Upper Miocene . . Germany (N.).
( Redonian (= Tortonian or Anversian) . France (N.W.).
Middle Miocene J Box-stones (=Bolderian of Belgium) . Britain.
(= Vindobonian) Italy, | Vienna
Helvetian—Tortonian . : : .. Basin, Holland,
| Pe ae
0 Burdigalian ‘ j ‘ , . France (S.W.).
REE ENCGSN® | CO Tar nna) (Ae AMM ame Denn Maat rey eee
t , Géologie de la Belgique, vol. i, p. 261, 1880.
* The foraminiferal evidence, also, lends support to the view that the
Coralline Crag is of older age than has yet been accepted. According to
the Monograph on the Crag “Foraminifera by Jones, Burrows, and others
(Paleontographical Society, 1897, p. 369) the following species are recorded
from the Coralline Crag of Sudbourne: Nwmmulina planulata, Amphistegina
vulgaris, Operculina complanata, and Orbitoides aspera, formerly determined
as O. fawjasi. These are said to be ‘‘ derived from earlier beds’’, although
from a recent examination of the specimens, which are,in the Geological
Department of the British Museum, they present the appearance of having
been found in situ. However, the so-called Nummulina might indicate an
Kocene or Oligocene horizon, but the other organisms are characteristically
Miocene, especially when it may be stated that in Orbitoides aspera, after
326 Reviews—P. A. Wagner—South African Geology.
Lastly, I may mention that in 1907 I was favoured with a visit
from the late Professor Dr. Gottsche, Director of the Hamburg
Museum, and one of the chief authorities on the molluscan fauna
of the North German Miocene deposits, for the purpose of examining
the Lenham Collection of the Museum of Practical Geology, which
was then in my keeping at the British Museum; he was specially
interested in some specimens referred to in Mr. Reid’s memoir as an
elongated variety of Zriton heptagonum (?), being confident that they
represented Beyrich’s Fusus sexcostatus, a characteristic fossil of the
Upper Miocene formation of North Germany. He was further of
opinion that the Lenham Beds were older than had hitherto been
supposed, and he considered that they should be referred to the
Miocene period.
REV LEws-.
1.—Some Propirems in Soura Arrican Gzotocy. By P. A.
Waener. Proc. Geol. Soc. South Africa, 1917, pp. xix—xxxix.
N his Presidential Address to the Geological Society of South
Africa for 1917 Mr. P. A. Wagner dealt at some length with
four outstanding problems of the geology of that country, namely,
the origin of the gold-reefs of the Rand, the genesis of the diamond,
alteration of diamonds after their formation, and the nature of the
famous salt pan near Pretoria. On each of these he had something
of interest to say. An excellent summary is given of recent views as
to the source of the gold in the Banket. Dr. Mellor has recently
brought forward evidence in favour of the ‘‘placer”’ theory, founded
largely on the actual distribution of the gold in the conglomerates.
It is found by assays that the gold is richest where the pebbles are
largest, and it is therefore argued that the gold was deposited by the
strong currents that brought the large pebbles, the weaker currents
that could bring only the finer sand not being competent to carry
the heavier grains of gold. Nevertheless, the actual character of the
particles of gold indicates recrystallization in place. Mr. Wagner
dissents from Dr. Mellor’s view that the quartzites and conglomerates
were deltaic deposits and regards them as having been formed on
beaches in a subsiding area.
The author considers kimberlite as the hypabyssal or yoleanic
form of a peridotite magma which he believes to underlie the granitic
and other rocks at a creat depth, and he regards the diamonds as
original constituents of this magma, brought up, often in a fragmental
form, during extrusion. He also gives some facts of great interest as
to the possible effect of radio-activity or other agencies on diamonds
after they reached their present position. This subject, however,
appears to be of a very speculative nature, and much work is
obviously required.
The salt pan on the farm Zoutpan, 25 miles N.N.W. of Pretoria,
now gives rise to’a considerable industry. The pan itself 1s a most
careful rubbing down of the horizontal surface on the median plane of the
figured example, there is exposed a series of minute chamberlets of squarish
or hexagonal outline which can only belong to the Miocene genus Lepidocyclina.
Reviews—E. 8S. Sumpson—Rocks, etc., W. Australia. 327
remarkable structure, and has been described by Cohen, Kynaston,
and Hatch & Corstorphine. It presents the appearance of a crater
lake, dry in winter, but until disturbed by working it contained
a brown brine in the rainy season. It is surrounded by a rim of
granite some 200 feet high, with a gentle slope on the outside and
a steep slope on the inside. The rim of granite is a most remarkable
feature. The floor of the pan has been pierced by borings to a depth
of 1,100 feet, and it is found to be composed of alternate layers of salt
and mud. The salts have on the average very nearly the theoretical
composition of trona, Na,CO; . NaHCO; . 2H20O, with some sodium
chloride but very little sulphate. The evidence as to the origin of
these salt deposits is scanty and not very satisfactory ; they may be
derived from the decomposition of the perthitic felspar of the granite
or from underground waters of either volcanic or meteoric origin.
Opinions differ as to the origin of the pan itself. It may be due to
the impact of a large meteorite, like Coon Butte in Arizona, or it
may be a volcanic pipe like the Maare of the Eifel or Geitsi Gubib in
South-West Africa; the latter appears the more probable, although
the upward bulging of solid granite in the form of a dome or even of
a ring seems rather difficult of belief. It is evident that the last
word has not yet been said on the origin of structures of this and
related types.
R. H. Rasratt.
I].—Awatyszes oF Western Avstrattan- Rocks, Mererorires, aND
Naturat Waters. By Epwarp S. Smmeson, B.E., B.Sc., F.C.S.
Bull. No. 67, Western Australia Geological Survey.
HIS bulletin is a collection of the records of all the analyses
performed in the Government laboratory between the years
1897 and 1916. It deals with rocks, meteorites, and natural waters.
The rocks are divided into igneous,metamorphic, and sedimentary,
_ and these divisions are subdivided according to silica percentage to
facilitate reference to the lists. The compiler states that these
analyses are not to be taken as a quantitative representation of the
rock-types of Western Australia, but that they deal, as is natural,
with the types of greater interest to the miner and the agriculturist.
In addition to the analyses of the igneous rocks, Brogger-Hobbs
diagrams are given of many types, and in most cases the ‘‘ mode”
and ‘‘norm”’ are given, and the rock is classified according to the
quantitative system.
Most of the rocks fall into the described groups, but two of them,
an amphibolite and a gabbro, fall inside no known group, and have
a sufficiently definite composition to warrant placing them in a new
group (IV, i, i, 3, 2), for which the name Murchisonose is proposed.
In the analyses of the sedimentary rocks two points of interest
present themselves. The first is the composition of the dune sands
from Dongara, which consist principally of foraminifera, calcareous
alge, and powdered mollusca, and have at times as little as 3°8 per
cent of silica, being almost entirely made up of calcareous matter.
The other point of interest is the excessive humidity of the
328 Reviews—British and Foreign Marbles.
bituminous coals, which often contain as much as 23 per cent of
moisture. Among the rocks there is a curious series of dyke or vein
rocks of unknown origin called ‘‘ hematite quartz rocks”, which
are placed in. a class by themselves. They consist principally of
hematite and chalcedony, and have an iron content of 47 to 54 per
cent of Fe2Os, which occasionally rises as high as 92 per cent in
the hematite rocks. In the section on meteorites twelve undoubted
siderites of nickeliferous iron are described, the large numbers of
doubtful obsidianites which have been found in the colony being
neglected. The natural waters analysed are drawn from a variety
of sources—artesian wells, surface wells, and mines. They are
used for drinking water, steam-raising, irrigation, stamp batteries,
and the cyanide process. The amount of solid matter is often very
high, sometimes reaching more than 15 per cent, which is principally
sodium chloride. It is interesting to note that in the surface waters
of one district there is a considerable quantity of sodium nitrate,
amounting to 19 parts of nitrogen to the million. This is attributed
to a train of favourable circumstances, there being great bacterial
activity in the soil, low rainfall, and a dominant vegetation of
a leguminous plant called ‘‘ mulga’’.
W. H. Wizcocxrson.
I1I.—Brrrisa anp Foreren Marpirs and orHER ORNAMENTAL STONES.
By Joun Watson. Cambridge University Press, 1916. ds. net.
‘Y\HIS descriptive catalogue is a companion volume to the same
author’s well-known Building Stones, and it shows the same
scholarship and regard for accuracy that characterized the earlier
catalogue. The rocks described include (besides marbles) onyx
marbles, malachite, alabaster, serpentine, and jade, as well as other less
common ornamental stones. The work will appeal very strongly to
the architect, and to the geologist who is interested in the application
of rocks to decorative purposes.
IV.—Tue Ercureoin Priocene or Mippte Catirornia. By Jorcen O.
' Nomutanp. University of California Publications, Bulletin of the
_ Department of Geology, vol. x, No. 14, pp. 191-254, pls. vi-xii,
2 text-figures. Issued April 19, 1917.
‘W\HIS memoir treats very exhaustively of the Etchegoin group of
rocks and its fauna as developed in the Coalinga District of
Middle California, which is considered to be of Pliocene age, although
mapped as Upper Miocene by Ralph Arnold and F. M. Anderson.
The author regards the vertebrate evidence as confirmation of this
horizon, Professor J. C. Merriam haying recently described from
these beds such genera as Pliohippus, Neohipparion, Mastodon, etc.
Faunal lists are drawn up of the marine invertebrates showing
a strong resemblance to those of the Jacalitos formation, which,
although hitherto kept distinct, may now, in the author’s opinion,
be united to the Etchegoin group. The memoir terminates with
descriptions of several new species of Mollusca—seven Pelecypoda
and 8 Gasteropoda—and a doubtful Serpula, all of which are suitably
figured. Be
OVO AR ee
ut
Reviews—New Tertiary Insects. eoiey ss)
YV.—Report or tHe Ruesy Scuoot Natrurat History Socrery FoR
THE YEAR 1916. 1917.
EOLOGY still maintains an excellent position among the various
sections of this Society. In the present Report (pp. 98-100)
it is noted that visits were made to Napton Quarry, and that fossils
were collected from the Capricornus zone of the Lower Lias. Some
pits at Nuneaton are also referred to as having yielded Carboniferous
ferns and Calamites, while marlstone fossils were obtained from
Fawsley Park, near Badby. Doubtless the better part of such
material will find its way into the School Museum, which already
contains good paleontological specimens, those of local interest being
perhaps of greatest importance. This Report also informs us that
the Rugby School Natural History Society has now been in existence
for fifty years, a fact on which we venture to offer our congratulations.
VI.—New Terriary Insects. By T. W. A. CockrrEert. Proce.
United States National Museum, vol. lii, pp. 378-84, pl. xxx1,
1917.
f{\HE material described in this paper was obtained from the Eocene
(Oil Shales) of Western Colorado, from the Miocene beds of
Florissant, Colorado, and from the Oligocene formation of Gurnet
Bay, Isle of Wight, belonging to the British Museum, although
originally in the collection of the late Rev. P. B. Brodie. The new
British forms described include:— Diptera: Riphidia brodiet,
Mongoma crucrferella, Tipula gardnert, Bibio gurnetensis, B. oligocenus,
Mesomyites (new genus) concinnus, Protoscinis (new genus) perparvus.
Thysanoptera: olothrips brodierx. Neuroptera: Sisyra (?) disrupta.
The new American species determined include:—Diptera: Plecia
winchester, from the Kocene (OilShales) of Colorado, and P. explanata,
from the Florissant deposits, the latter formation having also yielded
Acreotrichites (new genus) scopulicornis, Rhamphomyia hypolitha,
Urortalis (new genus) caudatus, Melierva atavina, and Anthomyra
persepulta. Hymenoptera: TZeniurites (new genus) fortis and
Hervades priscus, both from the Florissant Miocene.
VII.—Sourm Avsrratzma. Annvuat Report oF THE GOVERNMENT
Grotoeist [L. Kerrm Warp] ror 1915. Fol.; pp. 18, with
maps and tables. Adelaide, 1916,
(W\HIS report contains information on metallurgical subjects, water
supphes, mineral resources, building stones, etc. A very
important item of the year’s work concerns the discovery of precious
opal at Stuart’s Range at a place situated 81 miles west by south of
Anna Creek Railway Station. The specimens are stated to have
been evidently derived from the Desert Sandstone formation which
extends across Western Queensland and New South Wales into the
northern portion of South Australia. Valuable notes on the building
stones, which are regarded as Paleozoic and Tertiary, are set out in
a series of tables at the end of the Report.
330 Reports & Proceedings—Geological Society of London.
RHPORTS AND PROCHHDINGS.-
GerotocicaL Society oF Lonpon.
May 16, 1917.—Dr. Alfred Harker, F.R.S., President, in the Chair.
A lecture on ‘‘ British Geological Maps asa Record of the Advance
of Geology” was delivered by Thomas Sheppard, M.Sc., F.G.8. He
observed that geological changes were in many cases indicated on old
topographical maps ; consequently, very old plans and charts were
of use in connexion with geological inquiries, although not strictly
geological in character. Some examples of maps, dating from
Elizabethan times, were exhibited, and they showed that in the
Humber area great changes had taken place: in certain districts
large tracts of land had been denuded, and many towns and villages
had disappeared ; in others, large stretches of reclaimed land marked
places where water once stood. So long ago as 1595 writers were
familiar with lithological differences in various parts of the country,
and in 1683 Martin Lister read to the Royal Society a paperin which
he definitely suggested ‘‘A Scheme for the Mapping of Soils and
Rocks’’, wherein he mentioned the various kinds of rocks that
occurred in Yorkshire; but his scheme was not actually carried out
until a century later. Strachey (1719) and Packe (1748) produced
some remarkable geological sections and plans.
The first systematic series of maps, illustrating the geological
features of the counties, was issued in the Reports of the old Board
of Agriculture, and dated from 1793 to 1822. These reports usually
contained ‘‘ soil-maps” of the counties described, upon which chalk,
sandstone, limestone, peat, marl, gravel, etc., were shown by colours
and shading. William Smith was certainly familiar with these
‘‘ Agricultural Surveys’’, and doubtless they provided him with
information that assisted him in the preparation of his great map of
the geology of England and Wales, issued in 1815.
One of the earliest and most serious attempts to prepare geological
maps was by Professor Jameson, who read a paper in 1805 “On
Colouring Geognostical Maps” (Wernerian Nat. Hist. Soe., vol. i,
published 1811); but the enormous number of complicated signs and
symbols that he suggested proved unsuitable for practical purposes,
although there were many good features in his colour scheme.
The first strictly geological map (now in the Society’s possession)
was apparently that made by W. Smith in 1799, showing the
geological structure of the Bath District. This had been proved by
the lecturer to have been coloured on a plan originally issued in The
New Bath Guide of 1799. The first geological map of England and
Wales was a small one, also by Smith, and it was presented to the
Society by ‘‘the Father of English Geology”? when the first
Wollaston Medal was awarded to him in 1831. The lecturer dis-
cussed the history of the various maps and sections published by
Smith, and described two hitherto unknown maps (of the counties of
Durham and Northumberland) by the same author, in the Society’s
possession. He also exhibited one of the Scarborough district, found
whilst he was cataloguing the Society’s maps; all trace of th*s
ye!
‘J ¢
Reports & Proceedings—Geological Society of London. 331
particular map had been lost for over eighty years. Smith’s finest
piece of work, his map of the Hackness district, dated 1832,
apparently had not been seen by any worker since its publication,
and the lecturer explained how he had recently been able to trace
two copies. One of them, which was exhibited, he presented to the
Society.
In the Society’s possession also is an extensive and valuable
collection of the maps of Greenough, both published and in
manuscript. Among an extraordinary series of coloured maps of
England and Wales, and of the British Isles, issued during the
middle of the nineteenth century, those by Arrowsmith, Murchison,
Walker, Ramsay, Ravenstein, Knipe, Phillips, and Johnston are
especially noteworthy.
The Society’s collection includes geological maps of Scotland and
‘Ireland, some of great value and historical interest. Of Scotland,
the remarkable series by MacCulloch, published and in manuscript,
shows that the collection is by far the finest as regards early maps
dealing with the geology of the country. A manuscript map of
Scotland by Necker is dated 1808 (earlier than Smith’s large map of
England and Wales), and is undoubtedly the oldest. Among the
maps of Ireland there is the fine series by Griffith, which includes
a few examples not known by Judd or other writers on the subject.
As examples of privately published maps, those by Sanders of the
Bristol Coalfield, Jordan’s London District, and Elias Hall's
Lancashire area were described. The lecturer concluded by referring
to a catalogue of geological maps (other than the Geological Survey
publications) which he had in course of preparation. This already
contained details of approximately 3,000 maps.
June 6, 1917.—Dr. Alfred Harker, F.R.S., President, in the Chair.
The following communications were read :—
1. ‘‘On the Geology of the Old Radnor District, with special
-reference to an Algal Development in the Woolhope Limestone.”
By Edmund Johnston Garwood, Sec.D., F.R.S., F.G.S., and Edith
Goodyear, B.Sc.
The district comprises an inlier of Archean grits and Woolhope
Limestone forming an elongated dome bounded by Wenlock Shale.
It was regarded by Murchison and the Geological Survey as
consisting of Mayhill Sandstone succeeded conformably by Woolhope
Limestone, and they attributed the unfossiliferous character of the
sandstone and the abnormal facies of the limestone to alteration
by igneous intrusious. Dr. Callaway, in 1900, first suggested that
the so-called ‘‘Mayhill Sandstone” was of Archean age, and
recorded an unconformity at the base of the limestone. The authors
confirm Callaway’s views, and give evidence for correlating these
Archean rocks with Professor Lapworth’s ‘‘ Bayston Group ”’ of the
Longmyndian. The unconformable relation of the limestone to the
Archean is established in several portions of the district; while
a study of the Trilobite and Brachiopod fauna of the limestone and
included shale confirms the Wenlock age of the deposit. The most
interesting fact brought out by a study of the limestone is the
2 et oe
oye
hae ets
332 Reports & Proceedings —Geological Society of London.
important part played in its formation by the calcareous alga
Solenopora (of which a new species is described), the deposit
constituting by far the most striking development of algal limestone
yet recorded from British rocks. ‘The limestone represents a reef
facies of the normal Woolhope Limestone, being largely composed
of Bryozoa and calcareous Alge. Corals, although present, play
only a subordinate part. The reef appears to have grown round
a subsiding peninsula of Archean rock, which evidently then
formed the south-western continuation of the Longmynd range.
The same reef facies is also found to occur at Nash Scar, three miles
away to the north-east, where it rests on the Upper Llandovery
Sandstone. The sudden change to the normal type of Woolhope
Limestone at Corton, near Presteign, appears to mark the northern
limit of this lagoon phase.
The paper concludes with an account of the movements that
have taken place in the district, to which its general Caledonian
trend is due.
2. ‘Correlation of Jurassic Chronology.” By 8. 8. Buckman,
F.G.S. .
This paper owes its inception to certain discoveries made by the
Officers of the Scottish Geological Survey during their investigations
of the Jurassic deposits of the Isles of Raasay and Skye. The
Ammonites and Brachiopods were sent to the author for examination,
and the sequence of faunas which they disclosed necessarily led to
comparison with results obtained in other areas—with Yorkshire,
on which the author had recently written a paleontological chapter
for a Geological Survey memoir, based largely on information and
specimens submitted by the Survey; with the Dorset coast, helped
by Mr. W. D. Lang’s most painstaking work; with other areas
within the author’s field experience, helped largely by information
most freely communicated by Mr. J.W. Tutcher. The results appeared
to be so far-reaching that permission was asked of the Director of
H.M. Geological Survey to lay before the Society a synopsis of the
information obtained through the investigations of Survey Officers ;
this was kindly accorded, and the present paper is the outcome of
research thus originated.
One of the principles utilized in this paper to ascertain or to
surmise faunal sequence where precise information is defective, is
that of what may be called ‘‘faunal dissimilarity ’?—that is, if the
deposits of two neighbouring localities A and B, supposedly -
isochronous from their sequential position, show differing faunas, it
is a reasonable inference that the faunas are not of the same date.
Theoretical stratigraphical correlation has usually worked along
these lines, but the principle involved has not been recognized by
name. Now the principle is utilized, not only in regard to neigh-
bouring localities, but even more widely, with suggestive results.
The paper is chiefly concerned with the Liassic Ages hitherto
known as Domerian, Charmouthian, Sinemurian. In all of them
there is proposed a considerable increase of the number of faunal
liorizons indicative of consecutive time-intervals, or hemere. In
the case of the first no change of name is made; but in regard to
“49 Poe 9
- ;
Reports & Proceedings—Geological Society of London. 333
the other two, subdivisions seem necessary, and each is apportioned
into three Ages, as follows :—
Proposed Names. Old Terms.
Hiviccian.
Wessexian. - Charmouthian.
Raasayan. J
Deiran. |
Mercian. Sinemurian.
Lymian. )
These, with the Domerian, each contain on an average about ten
hemere, the grouping being controlled by the dominance of ammonite
families of phases thereof—thus, Domerian: Age of Amaltheids;
Raasayan: Age of Deroceratide and Echioceratide. It is obvious
that, with this increase in the nnmber of hemere, the number of
local non-sequences is greatly increased. Some comparative diagrams
illustrate this.
One of the most interesting discoveries which has resulted, partly
from the great thickness of Scottish strata investigated and collected
from, partly from comparisons with other areas, is that the so-called
““armatum Zone’’ of the English Midlands and that of the Radstock
district, of Yorkshire and of the Scottish Isles, are not isochronous,
but are separated by a time-interval which corresponds to a thickness
of some 300 feet of deposit in the Scottish area. Thus, instead of
the simple descending sequence
Deroceras armatum,
Hehioceras raricostatun.,
there is this sequence ascertained :
An upper Deroceras horizon,
An upper Hchioceras horizon in three distinct stages,
A lower Deroceras horizon,
A lower Hcehioceras horizon with some Armatoids ;
and even now possibly this is not the end of the complication. This
. alternation of Deroceras and Hchioceras involves a phenomenon which
the author calls “‘ faunal repetition ’”’, and it isa reasonable supposition
that this is not a solitary case—that is to say, doubtis at once thrown
on the contemporaneity of other so-called ‘‘ zones” where they have
been determined in different areas by the presence of certain species
of a genus—the species admittedly not the same—or by the alleged
presence of a single species on specific determination insufficiently
rigid... The cases of zones determined on the ducus a non lucendo
principle—the strata in correct intermediate position, but with the
index zonal species conspicuously absent—seem especially to invite
scepticism.
Three appendices are given—one, paleontological, containing
descriptions of certain notable species, mostly new; another,
historical, containing notes on certain ammonites described and
figured by Wright in a paper published some years prior to the issue
of his monograph: it affords clues to the interpretation of his
species, to the recognition of some of his missing types, to the
identity of certain figures in Reynés’s monograph, and to the geo-
graphical distribution of species—a matter of particular importance
334 Obituary—Thomas McKenny Hughes, M.A.
in regard to faunal dissimilarity; the third, geological—a com-
munication by Mr. J. W. Tutcher, embodying his reading of the
sequence in the lower part of the Lower Lias carried down to the
base of the Hettangian.
(@ Swede jy WIS 4 Na
PROFESSOR ROBERT BELL,
SO; MAD. D.Sc.) 0 lWDe aks. aetee
Born 1841. DIED JUNE 18, 1917.
Prorrssok Dr. Ropert Bett, F.R.S. (formerly Chief Geologist of
the Geological Survey of Canada, Ottawa), died suddenly on June 18,
1917, at Rathwell, Manitoba. Dr. Bell, who was 76 years of age,
joined the Geological Survey of Canada in 1857, and subsequently
made extensive topographical and geological surveys in various parts
of the Dominion. He acted as Medical Officer, Naturalist, and
Geologist combined on several expeditions to Hudson’s Bay and
Baffin Land. The Bell River, which he surveyed in 1895, was
officially named after him. He also made the first surveys of some
of the largest lakes in Canada. He was the Canadian correspondent
of the Royal Scottish Geographical Society since its foundation.—
Westminster Gazette, June 20, 1917.
THOMAS McKENNY HUGHES, M.A.,
Trinity College, Cambridge; Professorial Fellow of Clare College,
Woodwardian Professor of Geology; F.R.S., F.S.A., F.G.S.;
Chev. Ord. SS. Maur. et Lazar. Ital.; Corr. Memb. Soc.
Geol. Belg., Soc. Geol. France, Germany, Italy, etc.
BorN DECEMBER, 1832. DIED JUNE 9, 1917.
We deeply regret to record the death, on June 9, of our friend of
fifty years—a frequent contributor to the GroLtoeicaL Macazins—
Mr. T. McKenny Hughes, M.A., F.R.S., Woodwardian Professor of
Geology in the University of Cambridge, in his 85th year.
A life of Professor Hughes with a very excellent portrait appeared
in the Grorocicat Macazrne (n.s., Dec. V, Vol. III, No. 1, pp. 1-18,
January, 1906).
The following appeared in the Zimes, June 11, 1917 :—
Mr. T. McKenny Hughes ‘‘was born at Aberystwith, and was
a member of a distinguished family. His grandfather, Sir Thomas
McKenny, took a prominent part in Catholic emancipation in Ireland,
his father became Bishop of St. Asaph, and one of his brothers is
Bishop of Llandaff.
‘‘ Hughes was educated at Leamington and Llandovery Colleges,
and took his degree at Cambridge in 1857 as a member of Trinity
College. In 1860 he was appointed Secretary to the British Consul .
at Rome, and was left Acting Consul in that City in 1860 and 1861.
wd
Obituary—Lieut. Horas Tristram Kennedy, B.A. 335
In the latter year he joined the Geological Survey of Great Britain
and served on it until 1873, when he succeeded Professor Sedgwick
as Woodwardian Professor of Geology at Cambridge. At first his
survey work lay among the newer rocks of the south-eastern
counties, but in 1866 he was transferred to the borders of the Lake
District, where he did much important geological work.
‘‘On going to Cambridge his duties as successor to the eminent
Sedgwick were far from easy, but his varied attainments enabled
him to discharge them with success. At the outset, in addition to
the ordinary duties of his Chair, he devoted himself to three tasks ©
which had connexion with his predecessor—namely, the adoption
of the Cambrian system as defined by Sedgwick, the writing of the
life of that geologist, and the erection of the Memorial Museum
which has been built in his honour. The first of these would have
reopened an unfruitful controversy, and Hughes wisely discontinued
it. In carrying out the second he secured the services of the late
Registrar of the University—Mr. J. W. Clark—and ‘The Life and
Letters of Sedgwick’, by Clark and Hughes, appeared in two
volumes in 1890. The performance of the third task was long
delayed by many disappointments and difficulties, but Hughes had
the satisfaction of seeing the completion of the Sedgwick Museum,
which was opened by King Edward in 1904.
‘During his tenure of the professorship Hughes did much original
work in geology and archeology. He was a fluent lecturer, but
his most successful work as a teacher was due to his great capacity
for arousing enthusiasm among his pupils, and many geologists owe
their interest in the science to his efforts. He was elected a Fellow
of the Royal Society in 1889, and received the Lyell Medal of the
Geological Society in 1891, when he acknowledged the value of his
intimate association with Sir Charles Lyell, with whom he made
many geological tours during his early years. He was a Professorial
Fellow of Clare College, and Chevalier of the Order SS. Maurice et
Lazarus (Italy).
‘He married, on November 28, 1882, Mary Caroline, daughter of
the late Rev. G. F. Weston, Honorary Canon of Carlisle, and had
three sons. Mrs. Hughes, who has herself done important geological
work, was ever ready to assist her husband in the manifold duties
of his professorship [see Mrs. Hughes’ Memoir on the Pleistocene
Mollusca of Cambridge, Gron. Maa., 1888, p. 193 ].
“« As Sedgewick was elected Woodwardian Professor in 1818, he and
_his successor have between them occupied the Chair for ninety-nine
years.”
LIEUT. HORAS TRISTRAM KENNEDY, B.A., F.G.S.
Born 1889. KILLED IN ACTION, JUNE 6, 1917.
Lisur. Horas T. Kennepy, F.G.S., who was killed by shell-fire south
of Ypres on June 6, was a geologist of great promise on the staff of
the Geological Survey of Ireland, which he joined, after open
1 [For a list of his papers up to 1906 see the life of Professor Hughes, as an
“Eminent Living Geologist’’, GEoL. MAG., 1906, pp. 10-13; the titles of
ninety-three separate articles are there recorded. ]
TR Nae
336 Obituary—Upfield Green.
competition, in June, 1913. He was born in London, of Irish
parentage, in 1889, and gained a senior scholarship at Trinity
College, Cambridge, and a first-class in the Natural Science Tripos.
On entering the Survey he was employed on the revision of the
Leinster Coalfield, and was looking forward to work among Silurian
strata in the West of Ireland, where his undoubted powers of original
research would have been called forth. War, however, broke out,
and he obtained a commission in the North Staffordshire Regiment,
being transferred later to the Royal Scots Fusiliers. In the autumn
of 1916 he married the second daughter of the Very Rey. C. T.
Ovenden, Dean of St. Patrick’s, Dublin; Mrs. Kennedy had already
served for many months with a Voluntary Aid Detachment north of
Ktaples in France, including a winter partly spent in tents. At the
close of 1916 Lieut. Kennedy was attached to the Royal Engineers
for duties demanding scientific aptitude, and he was in command of
a section at the time of his death. His keenness in geological work
and his charm of personal manner make his loss deeply felt by his
colleagues on the Survey Staff.
GAC eens
UPFIBED GREEN, Nn Gro:
Born AuGust 4, 1834. Diep MAy 31, 1917.
Oor old friend Mr. Uptield Green, who had been failing for many
months, passed away suddenly at Bristol. He was born in London,
educated at Brighton and Neuweid, entered the London and County
Bank in 1852, became Master at Stourbridge School in 1855, and
the same year Overseer of the Wildberger Hiitte. The mine stopped
working in 1860, when Green returned to England and acquired the
old printing business of Groom, Wilkinson. & Co. He was an
enthusiastic geologist, but wrote nothing, until after thirty years’
observation and study of the geology of Cornwall had given him the
key to the tectonics of that county. In 1904 he published “ Note
-on the Correlation of some Cornish Beds with the Gedinnian of
Continental Europe”? (Gror. Mae., 1904); in 1909, ‘‘On the
Geological Structure of Western Cornwall” (95th Rep. Roy. Geol. Soc.
Cornwall), a paper which brought him the Bolitho Gold Medal; in
1912, ‘*Note on the Pollurian-Trewavas Coast Section, Cornwall”
(Guor. Mac., 1912); and in 1918, ‘‘On the General Geological
Structure of Western Cornwall, with a Note on the Porthluney—
Dodman Section” (Grou. Mac., 1913); the last two in conjunction
with C. Davies Sherborn. He had the great satisfaction of knowing
that his views on this difficult and controversial area were accepted
by many of his friends, especially in Belgium, France, and Germany.
He was materially assisted in his researches by his personal know-
ledge of the structure of the North of France, Belgium, and the
Rhine, and his familiarity with the fossils of the Continental
Devonian rocks. He became a Member of the Geologists’ Association
in 1886, and a Fellow of the Geological Society in 1889. He had
held for many years a geological ‘‘At Home” once a month, when
he gathered round him many friends.
Co Dames
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CONTENTS, ow
I. ORIGINAL ARTICLES. Page Ti See eee
Cretaceous Mollusca, New Zealand. The Tungsten Deposits of Essex-
By C. IT. TReCHMANN, D.Sc., vale. By A. EH: V. Zealley,
-F.G.S. (Plate XXI.) (Concluded.) 337 A.R.C.S8., South Rhodesia Geo-
Studies on the Echinoidea Holecty- logicaln Survey cercncaece eae 374
poida. By HERBERT L. HAWKINS,
M.Sce., F.G.S. (With five Text- ic espe.
ENF TES | a ee 342
‘Tertiary Dykes of the Clyde Area. G.M. Butler: Handbookof Minerals 378
By G. W. TYRRELL, A.R.O.Sc., H. F. Wickham: Fossil Beetles,
Pp. “6. S., Lecturer in Mineralogy,
ences apn eereity (Wan doc BCH Colorado sees se: 379
j Mest figures.) (Concluded.) ... 350 The Zoological Record ..............: 380
' On the Skeleton of Diplodocus as T. Sheppard, M.Se., F.G.S.:
j set up in the Natural History William Smith, his Maps and
Museum, by Dr. W. J. Holland. Mem Onsen yeaah ene pene 380
By the Rev. H. N. HuTCHINSON,
_ MA., F.G.S. (Plates XXII, Ve neg PROCEEDINGS.
_ XXIII, and nine Text-figures.) . 356
Il. NoricES oF MEmorRS. Geological Society of London— |
_ British Association : Conference of gis IT Besta i a)
_ ODelegates. Address by John British Association for the Advance-
Hopkinson, Hele Si BGA. ment of Science—
: Merten carne c Mian tes eanst 371 JunlyaO eho Woe se soree secs iol ws ts 384
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THE
GHOLOGICAL MAGAZINE
NEV ESERIES. DECADE Ml VOL. IV:
No. VIII. AUGUST, 1917.
ORIGINAL ARTIC
—— (a AUG 27 1917 %
I.—Creraceous Mortusca From NeW ZEALAND.
By C. T. TRECHMANN, D.Sc., F. Ost, a
(Concluded from the July Number, p. soo etal, Muse¥
(PLATE XXI.)
Apiustrum (?) SELWYNENsIS, sp. nov. (Pl. X XI, Figs. 1-3.)
HELL oval in shape, very thin, consisting of six whorls, the last
one very large andinflated. In some specimens the spire is rather
prominent, in others slightly depressed with rather deep sutures.
The apex and protoconch when not broken off are pointed and
prominent. The aperture is broad in front but narrow behind, and
seems to have a faint shallow anterior channel. There is no
columellar fold. The outer lip in specimens where it is preserved is
sharp and very slightly flattened out and expanded anteriorly. The
growth-lines are fairly prominent, and there is a tendency for faint
and shallow parallel furrows to develop, especially on the anterior
portion. Height about 18 mm.
This fragile shell is rather common, but often more or less crushed.
Aplustrum is the only genus to which I can refer it, but compared
with a recent specimen of A. amplustre it has a more prominent
protoconch, which in the recent form is rather sunken and buried.
The shell of the recent form also is smoother and more glossy.
Wilckens illustrates a shell (Bulla subglobosa)’ viewed from the
mouth side, from Quiriquina, which recalls the present form if seen
in a similar position and may possibly be identical. It cannot,
however, be a true Bulla as he says the spire is only slightly
depressed, while a characteristic feature of Bulla is the deeply sunken
and hidden spire.
I have also compared my specimens with the originai illustrations
of Bulla subglobosa and Philine chilensis of Philippi? and find that
they do not resemble the figures of either, as in both of them the last
whorl appears more swollen and the spire more sunken. It also
recalls Bulla glacialis, Wilckens,’ from the Tertiary beds of Seymour
Island, Antarctica, which, as Wilckens remarks, is very like though
more swollen than B. subglobosa of the Cretaceous of Quiriquina, but
1 N.J. fiir Min., Beil. Bd. xviii, pl. xviii, fig. 11, 1904.
2 Pert. w. quart. Versteinerungen Chiles, 1887, pl. xiii, figs. 2a, b, 4.
° “*Die Mollusken der Antarkt. Tertiarformation >: Wissensch. Ergebn. der
Schwed. Sudpolar Exped., p. 29, pl. i, figs. 36a-c, 1911.
DECADE YVI.—VOL. IV.—NO. VIII. 22
338 0. T. Trechmann—Cretaceous Mollusca
none of the figures show the elevated protoconch of the New
Zealand shell.
Locality.—Selwyn Rapids, rather common in one piece of rock.
Ho xcopiscus (Kossmariceras) eeMMatus, Hupé. (Pl. XXI, Fig. 6.)
Ammonites genmmatus, Hupé, Gay’s Hist. Chile, 8, 35, pl. i, fig. 3, 1854.
Holcodiscus gemmatus, Hupé, Steinmann, ‘‘ Ceph. d. Quiriquina Schichten ”’ :
N.J. fiir Min., Beil. Bd. x, p. 68, pl. vi, figs. 1a, b, 2a, 6, 1895.
Wilckens, ‘‘ Revision d. Fauna der Quiriquina Schichten ’’: N.J. fiir Min.,
Beil. Bd. xviii, p. 187, 1904.
Kilian et Reboul, ‘‘ Les Céphalopodes Néoerétacés des iles Seymour et Snow
Hill’’: Wissensch. Ergebnisse der Schwed. Sudpolar Exped., Stockholm,
1909.
A fragment of an Ammonite was obtained at Selwyn Rapids, but
owing to the blasting operation only about a third of the sutured
portion of the last whorl could be found. It has been partly crushed
and the sutures cannot be made out without destroying the specimen,
but the outer shell with its ornamentation is very well preserved.
The last whorl embraces about half the previous one and the umbilical
slope is steep, almost vertical. The venter is rounded and the ribs
cross it with great regularity. They are equally spaced on the
venter, but are less regular on the sides. Only about half the
number of ribs that cross the venter reach the umbilical shoulder,
approximately every alternate rib disappears rather less than half-
way from the venter to the umbilical slope. Of those that continue
two or occasionally three unite at the umbilical shoulder to form
a series of rather closely spaced sharp oval nodes whose apices are
directed backwards. ‘he ribs are slightly sinuous on the sides.
This fragment agrees so closely in external ornamentation with
the examples figured from Quiriquina and Antarctica that there can
be no doubt of its identity. It is common in the Upper Cretaceous
of Seymour Island, but has not been found in South Patagonia,
where, however, the three Indian species, 17. Theobaldinus, Bhawant,
and Amilianus, all of Stoliczka, occur. In addition to the three
forms just mentioned the Aryalur Beds of the Indian Senonian yield
the closely allied species, H. Madrasinus, Stol., Hand, Stol., and
Kalika, Stol.
Locality.—Selwyn Rapids, one specimen.
Beremnires sp. (Pl. XXI, Fig. 9.)
A single Belemnite fragment was collected at Selwyn Rapids.
It measures 24 mm. in length and forms the terminal part of a guard,
but no trace of phragmocone remains. It seems to have been rolled
and is split in two pieces longitudinally. The rock adheres so
closely to the outer surface that very little of this is visible. In size
and shape it resembles very closely some more or less rolled
fragments of Belemnite guards that occur at Brighton, 12 miles
south of Dunedin, in a hard pebbly shell bed resting almost directly
on the coal, which rests in turn on the eroded schists. Hector called
this fossil Belemnites Lindsaytz. The bed was classified as Tertiary
by the earlier New Zealand geologists, but this correlation will
probably have to be revised, and Professor Marshall is inclined to
Bik.
from New Zealand. 339
correlate it with the Wangaloa Bed. ‘The other fossils in it seem
to be very poorly preserved. Professor Marshall sent some specimens
of these Belemnites to Wilckens, who submitted them to other
specialists. Their opinion was that they were too much rolled for
accurate identification, but were certainly true Belemnites.
The present fragment, though clearly a true Belemnite, is too
poorly preserved for further determination, but its occurrence among
the fauna of Selwyn Rapidsis significant. For comparison I illustrate
two specimens of the Brighton Belemnite (Pl. X XI, Figs. 7, 8) which
were kindly given to me by Professor Marshall.
CoRRELATION.
The limited number of fourteen fossils under examination in the
present paper indicates the absolute agreement of the Cretaceous of
New Zealand with that of the rest of the Indo-Pacific region.
The Conchothyra parasitica beds at Selwyn Rapids and the
Waimakariri Gorge are clearly of the same age and correspond very
closely with the Pugnellus and Trigonia Hanetiana beds of Quiriquina
in Chili and the Pugnellus and Aporrhais gregaria beds of South
Patagonia. There can be no doubt that the Pugnellus bed in the
Waipara Gorge is also of approximately, if not of exactly similar, age.
Steinmann’ says, ‘‘ The Quiriquina Beds of South Chili are of the
same age as the upper division of the European Senonian, and definite
faunal relations exist between them.’’ Wilckens? regards the South
Patagonian higher Cretaceous beds as the equivalent or at least the
analogue of the Quiriquina of Chili.
It is thus a matter of interest to find in the same bed at Selwyn
Rapids in New Zealand species such as Aporrhais gregaria, which
occur in South Patagonia but not at Quiriquina, and Holcodiscus
(Kossmaticeras) gemmatus, which is found at Quiriquina but not in
South Patagonia, but which recurs at Seymour Island off the coast
of Graham Land in Antarctica.
The reported identification by Mr. Woods of a Gault fauna in
New Zealand has already been mentioned. It may turn out that
beds closely resembling those with Jnoceramus Steinmanni in South
Patagonia will also be found. It remains to be seen when Professor
Marshall’s work on the Wangaloa fossils is published whether this
fauna, which should apparently be of Maestrichtian age, finds any
close parallel in South America or elsewhere.
I found no Tertiary species among the Upper Senonian fossils of
New Zealand which I examined. Some Tertiary forms might be
expected to occur in the Wangaloa Beds, but for details of these
I await Professor Marshall’s report.
The number of Upper Senonian forms common to New Zealand,
South America, and Graham Land points to a much closer connexion
between these regions than obtains at the present day, and indicates
a land mass or a group of islands in the South Pacific joining New
Zealand to South America previous to the Tertiary uplift of New
1 N.J. fiir Min., Beil. Bd. x, p. 27, 1895.
2 Bericht der Naturgesell. Freiburg, 1907, Bd. xv, p. 63.
Trechimann—Cretaceous Mollusca
7
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340
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from New Zealand. 841
Zealand or of the South American Cordillera. This connexion
probably included a portion of the present continent of Antarctica.
In contrast to the large number of forms common to South
America and Seymour Island the slightness of the connexion with the
Australian Upper Cretaceous is shown by the presence of only one
Australian Gasteropod, Watica (Huspira) variabilis. This seems to be
the sole connecting link in the mollu-can fauna with the much
nearer continent of Australia. Hight species out of fifteen seem to
be confined to New Zealand. ‘I'he Upper Cretaceous of New
Caledonia is yet very little known, but according to Haug
Kossmaticeras Bhavani, of the Aryalour group of India, has been
found, and so it is possible that some forms at present thought to be
restricted to New Zealand may occur there.
I am indebted to Dr. A. Smith Woodward for the following notes
on some fish-scales discovered with the Cretaceous fossils described
above :—
‘The largest scales are evidently referable to Berycoid fishes.
They are much deeper than broad, with a relatively small and
somewhat thickened exposed sector. The best-preserved specimen
is shown of the natural size in Pl. XXI, Fig. lla, with a portion
enlarged four times in Fig. 116. Its extensive covered area is
marked by the very fine and numerous concentric lines of growth,
which tend to subdivide into minute granules near the edge of the
exposed area (Fig. 116). It is also slightly impressed with a few
grooves which radiate forwards and produce a waviness in the
concentric lines of growth where they cross them. ‘The small
thickened exposed area of the scale is ornamented with comparatively
large and rounded radiating ridges, which are feebly marked for the
greater part of their extent, but become raised into irregular
elongated tubercles near the anterior overlapped margin (Fig. 110).
The free posterior border of the scale is somewhat obscured by
matrix, but does not appear to have been sharply serrated. Part of
an apparently similar scale is clearly only wavy, not serrated, at the
posterior border.
‘A smaller scale, more incompletely preserved, is shown of three-
halves the natural size in Pl. XXI, Fig. 12¢, with a fragment of its
exposed area enlarged four times in Fig. 12b. The tissue is a little
disintegrated, but it displays the very fine concentric lines of growth
and the few radiating grooves in its covered area; while the hinder
border of its comparatively smooth exposed area bears coarse sharp
serrations and pectinations impressed again by the fine concentric
lines of growth. The imprint of the inner face of the scale seems to
show traces of the irregular tuberculation which has already been
noticed on the inner face of the scales of the Berycoid Hoplopteryz.
‘* Another well-preserved fish-scale, shown of twice the natural
size in Pl, XXI, Fig. 13, may be regarded as belonging to an
Elopine Clupeoid. Its large covered area, displaying extremely fine
concentric lines of growth, is crossed by numerous sharp radiating
grooves which have become clefts by crushing. Its denser exposed
area is nearly smooth, but bears faint traces of a few radiating lines.
842 Herbert L. Hawkins—Studies on the Echinoidea.
Usually in the scales of Elopines the radiating ornament on the
exposed area is more conspicuous than in this case; but similarly
feeble markings are observable on a scale in the type-specimen of
Thrissopater megalops from the English Chalk.
‘¢The fossil fish-scales from New Zealand thus belong to groups of
teleostean fishes which are abundant in Cretaceous formations in
other parts of the world.”
EXPLANATION OF PLATE XXI.
1-3b. Aplustrum Selwynensis, sp. noy. Selwyn Rapids. Fig. 3a x 14 nat.
size; Fig. 3b x 5 nat. size.
4a,b. Chrysostoma Selwynensis, sp. nov. Selwyn Rapids. xX 3 nat. size.
5. Trigonia cf. Hanetiana, d’Orb. Waimakariri Gorge.
6. Holcodiscus (Kossmaticeras) gemmatus, Hupé. Selwyn Rapids.
7, 8b. Belemnites sp. Brighton, south of Dunedin. Maestrichtian (?).
Fig. 8b x 13 nat. size.
¢)- Belemnites sp. Selwyn Rapids. x 13 nat. size.
10. Dentalium sp. Selwyn Rapids. x 2 nat. size.
11. Berycoid fish-scale, outer view, natural size (1la@), with portion of
adjoining covered and exposed areas enlarged four times (110).
12. Fragments of Berycoid fish-scale, outer view, preserved on inner
impression of same, three-halves natural size (12a) with portion of
exposed area enlarged four times (120).
13. Hlopine fish-scale, outer view, twice natural size.
[Plates XIX and XX appeared in the July Number. |
On Pl. XX, Figs. la and 6b and 3a and 6 should be transposed, an unfortunate
error having occurred in the numbering. The specimen figured at the left-hand
top corner really represents Pugnellus Waiparensis, sp. noy., and that at the
right-hand top corner represents the normal form of Pugnellus australis,
Marshall, from Wangaloa.
NotE.—In some of the copies the following correction is needed at the foot
of Plate XIX, which appeared in the July Number GEOL. MAG., next p. 304:
for CRET EHOUS read CRETACEOUS (two letters AC having accidentally
fallen out).—ED. GEOL. Mac.
1L1.—Morpnotoeicat Stupies on tHe KEcurnorpeA HoLeEcryPorIDA AND
THEIR ALLIEs.
By HERBERT L. HAWKINS, M.Sc., F.G.S., Lecturer in aie University
College, Reading.
TY. ‘Tuer Pertenaraic Greve oF THE Praagivemen
(WITH FIVE TEXT-FIGURES.)
1. Iyrropvuction.
f[\HE examination of the internal structures of Jurassic fossils is
attended with considerable technical difficulties. Even in
cases where the surrounding matrix is sufficiently friable for the
development of the external surface, the infilling material is usually
either thoroughly indurated or irregularly nodular in texture.
Internal moulds may be readily procured, both by natural weathering
and artificial processes. But such preparations, though adequate for
the investigation of shallow impressions such as the ‘auscle- scars of
Pelecypoda, are of uncertain service for the study of structures with
‘Grou. Mac., 1917. . Pirate NXT.
G. M. Woodward, del. Bale & Sons, imp.
UPPER CRETACEOUS FOSSILS, NEW ZEALAND.
Herbert L. Hawkins—Studies on the Echinoidea. 343
high relief. Specimens of Pygaster semisulcatus (olim ‘‘ P. umbrella’’)
are frequently found in the Corallian of Berkshire in the state of
decorticated moulds, and in such examples the presence of strong
perignathic prominences is indicated by deep pits on the adradial
sides of the branchial incisions. But attempts to reproduce these
perignathic structures by gutta-percha casts have hitherto proved
unsuccessful. The pits are so deep that it is almost impossible to
ensure their perfect emptiness; and they are internally expanded
and curved. For these reasons our knowledge of the perignathic
girdle of the Jurassic Holectypoida has up to the present been
practically confined to a realization that such a structure existed in
robust development. Lovén (‘‘ Recent Form of the Echinoconide”
and ‘‘ Kchinologica’’) ascertained something of its character by
means of sections, but was able to examine the more prominent
features only.
After many failures, I have succeeded in exposing the girdle, with
varying completeness, in two fully grown specimens of Plesvechinus
ornatus (olim Pygaster semisulcatus) from the Aalenian (Pea Grit) of
Leckhampton. In many examples there is a cylinder of fairly
yielding matrix connecting the apertures of the periproct and
peristome, while the limestone wholly sheltered by the test is in
a very refractory state. In the two specimens on which this paper
is based, the soft plug, though containing many pisolite grains, was
slightly greater in diameter than the peristome; and so it was
possible, by slicing off the adapical surface, to expose all of the
perignathic structures in one instance and the adoral parts of them
in the other. The more completely developed specimen is now in
the collection of the Geological Department, University College,
Reading, registered number 924.
The structures shown in the prepared specimens have a special
interest in view of the primitive qualities of the genus Plestechinus.
In the present paper a brief comparison is made between the
perignathic girdle of the Pygasteride and that of the simpler types
of the Diademoida (Centrechinoida). For the purpose of this
comparison I have used Jackson’s summary and diagrams given in
his ‘‘ Phylogeny of the Echini”’, pp. 189-195, reinforced by a few
observations of my own. A detailed comparison with the later
Holectypoida and the Clypeastroida (in which, thanks to the work
of Lovén and Duncan, the girdle is already well known) is postponed
to a later paper partly prepared.
2. Tue Prrignatuic Girpin oF PLESIECHINUS ORNATUS.
(a) The relations of the basi-coronal plates. (See p. 344, Fig. 1.)
The peristome of Plestechinus (and of all Jurassic Pygasteride)
is approximately circular in outline, but the circumference is
strongly ‘‘festooned” by profound branchial incisions. These
incisions, as is usual in Ectobranchiate Echinoidea, involve those
parts of the interambulacral margin that are contiguous to the
ambulacra. As may be seen by reference to Fig. 1, the branchial
incisions are not equidistant, the measurement across an ambulacrum
being greater than that across an interambulacrum. The actual
H. L. Hawkins del. i Lee
Fic. 1. Peristome of P. ornatus, external view. x c. 3.
ND: A i a, internal view. x ce. 3. Coll. Univ. Coll.,
Reading, Geol. Dept., No. 924. The figure is partly restored, several
of the processes having been broken during development.
53 Oral aspect of a pair of processes. x c. 6.
sates ip », an interradial ‘‘ridge”’. x c. 12.
He OO
Herbert L. Hawkins—Studies on the Echinoidea. 345
amount of peristomial circumference (reduced to a simple circle)
built up by the two areas is approximately the same, but the
interambulacral portion is entrenched upon by the branchial
incisions. ‘The ambulacra present a semi-elliptical margin to the
peristome, while that of the interambulacra is more nearly semi-
circular. ‘he ambulacral pores, which are not crowded nor much
displaced from their direct line, pass down near to the adradial sides
of the branchial incisions, and curve round with the margin of
their areas.
‘The primordial, unpaired plate of the interambulacrum is
preserved as a small, triangular ossicle. The interradial sides of
the branchial incisions are formed of the edges of two or three
paired interambulacral plates, and the single plate occupies only the
apex of the semicircular margin of the area. Lovén(‘‘ Recent Form
of the Echinoconide ’’) recognized the persistence of the unpaired
plate in Plescechinus.' It is interesting as showing that this
typically Spatango-Clypeastroid feature was developed at the very
outset of ‘‘ Irregularity ’’.
A slight groove extends along the border of the interambulacrum
from the branchial incision to nearly half-way across the adoral
surface. It is marked by the absence of large ornament, the presence
of guttate granules, and the development of small pits on the
transverse sutures. As will be seen later, this specialized region
coincides in position with a definite internal structure.
The adoral surface of Plestechinus is slightly concave, but at
a region nearly coincident with the position of the apices of the
branchial incisions a decided, though short-lived, invagination sets
in. ‘lhus the basi-coronal plates at the peristomial border are
almost vertically disposed. All the plates of the adoral surface are
surprisingly thin, even in large and gerontic individuals where the
adapical plates are massive.
(b) Zhe ambulacral processes. (See p. 344, Figs. 2, 3.)
These structures have been partially described by Lovén (loc. cit.).
They present an anomalous appearance when partly cleared of
matrix. ‘They seem to be massive, ridge-like prominences, situated
obliquely to the radius across the actual adradial suture, and
to possess an escarpment-like adoral end, with a steep ‘‘ dip-slope”’
passing adambitally and soon merging into the general inner surface
of the test. ‘They obviously spring from the ambulacrum near the
peristomial margin, but are quite as clearly based upon the
interambulacral plates for the greater part of their extent. When
the preparation of the specimen is complete the explanation of this
peculiar anomaly is seen. ‘The actual process is a slender, lath-like
projection rising from the ambulacrum near the adradial margin and
} Lovén (Etudes, pl. xiv, figs. 124 and 125) has shown the primordial
interambulacral also in Holectypws and Discoides. It is almost unnecessary,
if not presumptuous, to confirm the accuracy of Lovén’s observations on
Kchinoid structures; but in the case of his fig. 124 (Holectypus) I have
a prepared specimen which agrees with his drawing in even the minutest
particulars.
346 Herbert L. Hawkins—Studies on the Hchinoidea.
leaning outwards towards the interambulacrum, though practically
vertical when viewed from the branchial incision. ‘he process is
narrow at the base, and a little broader at the summit, where it
is capped by an ovoid expansion which overhangs its sides. It
leans against, and is visibly sutured to, a much more massive
buttress which is almost wholly interambulacral in position, and
constitutes the ‘‘dip-slope’”” of the whole structure. Lovén
(‘‘ Echinologica’’) seems to have ascribed this buttress to the
ambulacrum in its entirety, but this is contrary to my observations.
His meaning is rather difficult to follow in the passage (loc. cit., p. 51)
dealing with this structure. The buttress has a rounded crest,
which overhangs, in a slight eave, the concave hollowing of its
side adjacent to the branchial incision. The whole buttress, at first
directed in a line continuous with that of the process, gently curves
back towards the adradial suture, near to which, but on the
interambulacral side, it passes until it sinks to the general level of
the test. The position of this buttress is indicated externally by
the specialized smooth area referred to above (section 2, a). ‘The
texture of the stereom of the buttress is different from that of the
process, the former being soft and friable, while the latter is almost
porcellanous. It is obvious that the buttress is no part of the
perignathic girdle strictly speaking, but is merely a strengthening
structure for the better support of the process, and the stiffening
of the extremely thin plates in the region of the peristomial
invagination.
In the more important specimen, the diameter of which is 74 mm.
(the peristome being 12 mm. across), the average height of the
processes, measured from the internal surface of the test at their base,
is almost exactly 3mm. The interradial buttresses extend towards
the ambitus for a distance of about 8mm. from the apices of the
branchial incisions.
The ambulacral pores pass between the bases of two processes
without perforating them and without being deflected from their
straight course. They pierce the test very obliquely near the
peristome, but otherwise show no disturbance due to the processes.
I have seen no trace of a suture at the base of any of the twenty
processes examined, but these lines are so faint on even recent tests
that there is no reason to doubt their occurrence.
In the perradial line, just at the peristomial margin, there is
a small ovoid prominence or thickening of the invaginated edge of
the ambulacrum. This unpaired structure is probably not a part
of the girdle, in as far as that apparatus serves as a support for the
jaw-muscles. Of itself the prominence is of trifling importance, but
a similar thickening of much greater relative size occurs in Conulus,
so that its presence in Plesiechinus seems worth recording.
(c) The interradial ‘‘ ridges”. (See p. 344, Text-figs. 2, 4.)
At first sight the perignathic girdle seems to be composed solely
of the ambulacral processes above described, the equivalents of the
ridges (Duncan) or apophyses (Jackson) being so feebly developed.
There is a slight thickening of the test along the margins of the
Herbert L. Hawkins—Studies on the Echinoidea. 347
branchial incisions, but this is presumably for the purpose of
affording a safe exit for the branchiew, and has nothing to do with
the jaw-apparatus. But on careful investigation it is seen that the
invaginated rim of the primordial interambulacral plate is thickened,
and leads up by a concave curve to a small, rounded prominence
which lies in the median interradial line. There is, in fact, a very
slight ridge, extending across the projecting portion of the
interambulacral margin, and culminating in a central prominence
whose axis is considerably inclined from the vertical. At each side
of the central knob (which is less than one-sixteenth of the height
of the ambulacral processes), the ‘‘ ridge” shows a slight drop, as if
to render the prominence more conspicuous. A very delicate, blunt
carina passes adorally from the knob to the margin of the peristome,
dividing the concave slope of the ridge into two halves. As far as
I have been able to determine, the adambital side of the ridge is
slightly undercut, so that it overhangs the interambulacrum. In this
respect, as in the development of a median carina, this feeble section
of the perignathic girdle resembles that of many Diademoida. The
homologies between its several parts and those of the Cretaceous
Holectypoida will be discussed in the forthcoming paper to which
reference has already been made.
(d) The distribution of the lantern-muscles. (Fig. 5.)
The lantern of Plesiechinus is at present unknown as regards its
detailed structure. That of Discoides only, among the Holectypoida,
has been adequately described. It is, however, quite unnecessary to
argue the question of its presence or absence in the Jurassic genus.
During the development of one of the girdles above described, I cut
through certain delicate Echinoid ossicles which were without doubt
portions of pyramids, but the refractory nature of the matrix made
it impossible to see any but sectional views of them. For the
purpose of reconstructing the musculature of the jaw-apparatus it is
necessary and reasonable to suppose that the lantern was essentially
similar to that of the Diademoida, with tendencies in the direction
of that of Discordes and the Clypeastroida.
Fig. 5.—Schematic restoration of the attachment of the lantern muscles to
the perignathic girdle in Plesiechinus. pr. protractors, re. retractors.
The hypothetical radial compass muscles are indicated by double broken
lines.
There can be little doubt that the retractor muscles were attached
to the upper parts of the ambulacral processes, on their interradial
348 Herbert L. Hawkins—Studies on the Hchinoidea.
faces. Retractors based upon the two sides of an arched “auricle”
serve hemi-pyramids belonging to two separate maxille, and so
normally diverge. The planes of the interradial faces of the
processes in Plesvechinus are themselves directed away from one
another, so that a divergent pair of retractors could spring from them
practically at right angles to the articulating surface.
The protractor muscles must have been based either upon the
incipient ridges (as they would be in Diademoida), or else far back
and low down on the interradial sides of the processes (after the
manner of Clypeastroida). ‘The feebleness of the interradial elements
of the girdle in Plesvechinus would tend to suggest the latter
alternative, but nevertheless I incline to believe that they had the
former position. In Discovdes and Conulus there is no ‘ interradial
face’’ to the process, which rests against, and is sutured to, a ridge-
like thickening of the test of practically the same height as itself.
And the two concave bays, resembling ‘‘ combes” on an escarpment,
that occur on the adoral surfaces of the small ridges, seem to demand
an explanation which is most satisfactorily given by calling them
muscle-impressions. Plestechinus is far more like a Diademoid than
a Clypeastroid in general characters, so that the balance of probability
would place the protractors on the ridges, insignificant though
they are.
The only other series of jaw-muscles that are attached to the
perignathic girdle in Diademoida are the slender ‘‘radial compass
muscles”’, which diverge from the forked ends of the compasses.
They spring from the ridges, above and behind the protractors, in
the Regularia Eetobranchiata. The two slight depressions on each
side of the central interradial knob are extremely suggestive of sites
for the attachment of these muscles. But if the depressions had this
purpose their presence wouldimply the existence of compasses in the
lantern of Plestechinus. Compasses are not known in Doscoides
(though their fragile nature might well account for their non-
preservation), and they are definitely absent from the Clypeastroid
lantern. The existence of radial compass muscles in Plesvechinus
must therefore be regarded as problematical. In the accompanying
restoration, I have inserted them as dotted lines in the position
that they would presumably have occupied if they were developed.
There is no indication of the existence of any additional retractor
muscles, such as occur in the Clypeastroida, but on the other hand
there is no reliable proof of their absence. The processes, apart from
their supporting buttresses, are so slender that they seem unlikely
to have given support to more than the single retractors.
3. Tae Perienataic GinpLE oF Pre@asTeR AND HOLECTYPUS.
As far as can be judged, there is no essential difference in the
position and relative proportions of the elements of the girdle in ~
Pygaster semisulcatus from that already described. I have studied
the apparatus only from internal moulds of this species.
In Holectypus hemisphericus and depressus I have succeeded in
clearing the inner parts of the peristome sufficiently to reach the
adoral edges of the processes, which are like those of Plestechinus in
L258 Lei Mey hb py,
Herbert L. Hawkins—Studies on the Echinoidea. 349
all the features shown. By means of serial sections, it has been
possible to recognize that the whole girdle, in both species, is
practically identical with that already described. The buttresses
have similar characters in all three genera, but seem to be shorter
and steeper in Pygaster, and less massive in Holectypus. In both the
genera last named the plates of the adoral surface are exceedingly
thin—more so proportionately than in Plesiechinus—so that actual
development of the inner surface is a matter of great difficulty, even
when the outer surface is still encased in matrix. The infilling
material is generally completely indurated in Holectypus, and when
a band of less refractory rock is found it proves to be a thin film
in contact with the test along a narrow belt connecting the peristome
with the periproct.
4. A COMPARISON BETWEEN THE PERIGNATHIC GIRDLE oF PLESI-
ECHINUS AND THAT OF PRIMITIVE Recutar EcHINOIDEA.
The perignathic girdle of Plesvechinus is definitely Diademoid
(Centrechinoid) in character, and shows no affinity to the Cidaroid
type. That is to say, its major elements are situated on the
ambulacral plates; the interradial ridges of the Cidaroida being
practically unrepresented. ‘The interradial buttresses have evidently
no homology with the Cidaroid ridge, being behind the true girdle,
and having a merely mechanical function for the better support of
the fragile adoral surface. They reach their fullest development in
Discovdes and the Clypeastroida. The sudden and complete trans-
ference of the ‘‘auricle’’ from the interambulacrum to the ambulacrum,
which accompanied the change from the Cidaroida to the Diademoida,
is one of the chief gaps still unbridged in the evolutional history
of the Echinoidea. The process was absolutely completed in the
Pygasteride.
The two vertical, unarched processes on the ambulacrum are in
keeping with the general Jurassic character for the girdle. The
Calycina, Hemicidaris, Pseudodiadema, Stomechinus, and even the
Cretaceous Cyphosoma all possess ‘‘disjunct’’ auricles. And in all
the genera except the last named the interradial portions of the
girdle are very feebly developed. ‘These features are morpho-
genetically neanic, or perhaps nepionic; the girdles of later
Echinoids which possess elaborate structures all passing through
a stage comparable with this Jurassic phase. The central knob on
the ridge is a feature very constantly found in those Diademoida
which have interradial developments of the girdle (e.g. Salmacis).
But in three important respects the Pygasterid girdle differs
from that of the Diademoida. The processes are situated at
the extreme interradial edges of the ambulacra, and are not
perforated by the ambulacral pores. In the Diademoida the
processes often spring from expanded bases which involve
practically the whole width of the ambulacral columns, and
are in consequence passed through by the podial pores. In
Plesiechinus the processes are inclined away from the margin of the
peristome, while in the Diademoida they rise directly from, and
almost at right angles to, the margin. And lastly, the processes of
350 G. W. Tyrrell—Tertiary Dykes
the Pygasteride, so far from converging across the ambulacrum,
actually diverge, while Diademoid processes, even when they do not
meet in an auricular arch, are always inclined towards one another.
These three points of difference are all in a sense prophetic of the
subsequent perignathic changes in Holectypoida and Clypeastroida.
The wide basal separation and increasing divergence of the processes
suggest the future shifting of these structures to an interradial
convergence as seen in Clypeaster, and more completely in
Echinocyamus or Echinarachnius. The situation of the processes of
Plesiechinus well back from the peristomial margin is found in
a greater degree in the Clypeastroida, and implies a considerable
inclination of the lantern away from its typically vertical position in
Regular Echinoidea.
The interradial ridges, feeble though their development is, have
strong points of resemblance with the homologous structures of
Discoides and Conulus, as I hope to show in a forthcoming paper.
It thus appears that the perignathic girdle of the Pygasteridz
shows a very close correspondence with that of phylogenetically or
ontogenetically young Diademoida as regards the essential disposition
of its elements; but that in its details it already indicates
a progressive tendency towards the Clypeastroid type of girdle. The
development of the short interradial buttresses, though clearly an
adaptation to the requirements of the thin invaginated peristome,
represents another foreshadowing of a typically Clypeastroid feature.
Il].—Somsz Tertiary Dykes of THE CrypE ARRA.
By G. W. TYRRELL, A.R.C.Sc., F.G.S., Lecturer in Mineralogy and
Petrology, Glasgow University.
(Concluded from the July Number, p. 315.)
Lemierre and Iynrymorite.—Typical rocks of these groups are
as yet unknown in the Clyde area. A N.N.W. dyke at Barrassie
Sands, near Troon (Ayrshire), has points in common with leidleite.
It shows anorthite phenocrysts in a subvariolitic groundmass of
acicular felspar and augite, enveloped in a partially devitrified glassy
base. A north-south dyke at the north end of Loch Fad, Bute, may
perhaps be regarded as a doleritic end-variety of leidleite (see
Anderson & Radley, 1916, fig. 2b, p. 208). A pitchstone-like dyke
from the Smurig Burn in the south of Arran has all the characters
of leidleite, except that it carries rather abundant granular augite,
instead of acicular crystals.
Tuotente (Brunton Type).—This type has been based by the
petrographers of the Geological Survey on the so-called ‘‘ augite-
andesite’ of the Brunton dyke, Bingfield, Northumberland, figured
by Harker (1908, fig. 54, p. 208), and described and figured by
Teall (1884, pp. 236-7). It is abundant among the Tertiary dykes
of Mull, and two analyses of the type have recently been recorded
(Geological Survey, 1914, p. 82; 1915, p. 55). In the brief notes
accompanying the analyses these rocks are said to be composed
respectively of ‘“‘small clots of augite and acicular crystals of
plagioclase, with interstitial dark-brown glass”, and of “‘augite,
of the Clyde Area. 351
moderately basic plagioclase, magnetite, and of dark’ interstitial
glass”. Teall describes the microscopical character of the Brunton
dyke as follows: ‘‘long, narrow, lath-shaped felspars, irregular
erystalline grains and plates of a nearly colourless pyroxene, and
a small quantity of nearly opaque interstitial matter.” The rock is
figured in pl. xii, fig. 6, of his paper. Judging from the figures
given by Harker & Teall, and from thin sections of Brunton types
from the North of England dykes in the collection of the Geological
Department of Glasgow University, the felspar and augite are
approximately equally developed, with perhaps a slight excess of
the pyroxene, and the amount of glass is only slightly subordinate
to either of the crystalline constituents. The Tynemouth dyke and
several of the Ayrshire examples carry large phenocrysts of bytownite
or anorthite of exactly the same characters as in cumbraite or
inninmorite. Magnetite may or may not be present, and the texture
is typically intersertal or tholeiitic. The type is clearly more basic
than leidleite, inninmorite, or cumbraite, a fact reflected in the
diminished quantity of glass. Norms calculated from the analyses
of the Brunton type published by the Geological Survey show no
quartz and 5 per cent of orthoclase in the 1914 analysis, and
4°2 per cent of quartz and 5:5 per cent of orthoclase in the 1915
analysis. Both rocks fall into the subrang camptonose (III, 5. 8. 4),
showing at once that they are richer in the femic minerals than
cumbraite, etc., and that there is only a negligible amount, if any,
of excess silica.
Fic. 2a.—Tholeiite (Brunton type), N.N.W. dyke, Stairaird, River Ayr, near
Mauchline, Ayrshire. x 20. Large phenocryst of bytownite-
anorthite ; groundmass: grains of augite, and laths of labradorite, in
base of dark glass.
», 2b.—Olivine-tholeiite (Corrie type), N.N.W. dyke, Birchpoint, Corrie,
Arran. x 20. Corroded phenocrysts of bytownite-anorthite ; ground-
mass: laths of labradorite, grains of augite, olivine, and magnetite, in
scanty base of dark glass.
352 G. W. Tyrrell—Tertiary Dykes
The Ayrshire examples of the Brunton type of tholeiite may be
represented by a N.N.W. dyke crossing the River Ayr near Stairaird,
Mauchline. This rock (Fig. 2a) shows clusters of almost colourless
granular augite, intermixed with diversely arranged, short felspar
laths (Ab; An,), all held in a black glass. The phenocrysts consist
of bytownite-anorthite with a narrow rim of labradorite, exactly
similar to those of cumbraite. A rough estimate of relative
proportions is about 35 per cent each of the groundmass felspars and
augite, 20 per cent glass, and 10 per cent of anorthite phenocrysts.
A very small amount of olivine, fresh in this rock but serpentinized
in the others, may be detected. On examination by a high-power
objective the ‘‘ black ”’ glass turns out to be colourless, but charged
with swarms of opaque black microlites. N.N.W. dykes conforming
to this type, and exhibiting only minor variations in the quantitative
relations of the minerals, occur in the River Ayr at Failford, near
Tarbolton; in the Broadlie House Burn, near Dalry; and in the
Coachford Burn, Cooperhill, Ochiltree.
Tholeiites of the Brunton type do not appear to be common in
Arran, only three examples being known in a large suite of the
Tertiarydykes. These dykes occur in the South Locherim Burn, Corrie;
at 1,588 feet on the Saddle, between Glen Rosa and Glen Sannox;
and on the shore near Largiemeanoch, Whiting Bay. Likewise
Dr. W. R. Smellie’s slides of the Tertiary dykes of Bute show only
three examples belonging to the Brunton type, adyke at the south
end of Loch Fad; in the quarry behind the Power Station, Ardbeg,
Rothesay ; and on theshore south side of Stravannan Bay. Only one
dyke of the Brunton type occurs in the Great Cumbrae, a north-west
dyke, 11 feet thick, at Portachur Point.
Ouivine THotetrre.—These dykes appear to represent a further
and more basic stage than those of the Brunton type, although
preserving a sufficient community of character with the foregoing to
warrant the view that they are a continuation of the same series.
They are characterized by the presence, often an abundance, of fresh
olivine, and by the presence of a glassy base in minimum quantity.
No chemical analysis of this group has yet been made. ‘l'wo types
are recognized according to the relutive abundance of olivine. The
first type, characterized by a small quantity of olivine and by its
restriction to the groundmass, is represented by a large group of
dykes near Corrie, Arran, and may accordingly be known as olivine
tholeiite of the Corrie type. A typical example is provided by
a dyke at Birchpoint, on the shore south of Corrie. This rock
(Fig. 26) carries numerous small phenocrysts of bytownite-anorthite
with narrow labradorite margins. These crystals are often worn
and corroded into curiously irregular shapes, and have glassy
inclusions arranged in a thick marginal zone which faithfully follows
the fantastic outlines of the crystals. The groundmass consists of
a diverse mesh of short laths of labradorite (Abi Ani), intermixed
with granular or short prismatic crystals of a pale, violet-brown
augite which is the most abundant constituent of the groundmass.
Minute grains of olivine, partially or wholly serpentinized, and of
euhedral magnetite, are uniformly scattered over the field, but form
of the Clyde Area. 353
minor constituents of the groundmass. The interstices are filled by
a colourless glass, darkened by innumerable globulites. Quantitatively
the glass forms probably less than 10 per cent of the total rock.
Minute spherical vesicles filled with dark glass are rather abundant.!
Rocks of this type occur freely near Corrie, but have not yet been
found elsewhere. ‘hey vary within small limits of quantitative
relations and texture.
The second type may be known as the Largs type owing to the
occurrence of two beautifully fresh dykes on the shore near the town
of Largs, Ayrshire. An extended description of these rocks is
unnecessary, as they differ from the Corrie type only in the much
greater abundance of olivine, not only as granular constituents of the
groundmass, but as large phenocrysts. In the groundmass (Fig. 3a)
there is an augmented proportion of augite relative to the other
constituents, and a diminished, almost vanishing, proportion of
glassy base. A dyke of this character also occurs in the gorge known
as Creag Bhan, Whiting Bay, Arran. This type may be regarded as
the most basic of the tholeiitic series of Tertiary dykes.
Fic. 3a.—Olivine-tholeiite (Largs type),
Pier, Largs, Ayrshire. = 20. Phenoerysts of anorthite and olivine ;
groundmass: laths of labradorite, grains of augite and olivine, in scanty
base of dark glass. x 20.
,, 30b.—Crinanite, N.N.E. dyke, high road above Cordon, Lamlash, Arran.
x 20. Ophitic plexus of titanaugite and labradorite laths, with
abundant olivine and magnetite. Fresh, colourless analcite in triangular
interstices between the felspars.
Opuitic OttvinE-Doterith anp Crinanire (Fig. 36).—The dykes
of this group stand apart from those belonging to the tholeiite series,
and, as far as present knowledge goes, appear to belong to an earlier
phase of Tertiary volcanic activity in the Clyde area. A crinanite
dyke from Whiting Bay, Arran, was described some years ago
(Tyrrell, 1913); but a large number of these dykes have since been
* For a figure of this rock see Tyrrell, 1909, Pl. XIX, Fig. 5.
DECADE VI.—VOL. IV.—NO. VIII. 23
? Te ee ee oe
\r ewe. .
354 G. W. Tyrrell—Tertiary Dykes me if
discovered all over the Clyde area. The true crinanites are
inseparably associated with, and may be shown to pass into by
a graduated series of sections, ophitic olivine-dolerites, which differ
from them only in the absence of analcite or radial zeolites. The
group is typically non-porphyritic, free from -glass, and rich in
olivine. In general the rocks are so fresh that it is difficult to
believe that the interstitial analcite and zeolites can be other than
primary constituents. The crinanites are ophitic olivine-anaicite-
dolerites of mafelsic composition, i.e. the felspars are quantitatively
approximately equal to the combined olivine, augite, and iron-ores.
The chemical analysis of a typical crinanite from Inver, Jura (Flett,
1911), gives a norm which falls into the subrang auwvergnose of the
American Quantitative Classification, but very close to ornose (III, 5
(3)4.’5). It shows 1°5 per cent of nepheline, and consequently
the rock falls into the ‘‘ unsaturated’ group of Shand, whereas the
tholeiites are quartzose and fall into the ‘‘ over-saturated’’ group.
A typical example from Whiting Bay is described in the above-
cited paper. The felsparis much in excess of the augite, so that the
small plates of the latter mineral are cut up into thin, detached,
triangular strips by the felspar laths. The augite is always the
deeply coloured, brown-violet, titaniferous variety. The olivine is
generally quite fresh, and occurs in rounded grains which are
uniformly distributed over the field. The interstices are filled with
analcite or radial zeolites, but the amount is always small, much
smaller than in the teschenite group. When the olivine happens to
be serpentinized, the green material appears to migrate into the
interstices and obscures the presence of analcite. Some of the dykes
may thus be set down as olivine-dolerites when they are really
crinanites. ‘The rocks vary in coarseness of texture from almost
gabbroid to basaltic types, according to the size of the intrusion.
They usually occur as broad, massive dykes, which may in some
cases have feeder relations to the great crinanite sills of the south of
Arran. Besides the Whiting Bay dyke mentioned above, crinanites —
are now known to occur in Arran at the following places:
Kingscross Burn, a quarter of a mile south-west of Kingscross
Bridge; by the high road above Cordon, Lamlash (Fig. 36); on the
shore south-east of Cordon, Lamlash; the shore a quarter of a mile
north of the Pier, Brodick; Invercloy, Brodick; and An Sgriob
Quarry, 2 miles south of Corrie. Related olivine-dolerites occur at
the first fall in Glen Ashdale, Whiting Bay, and on the shore near
Dunfion, Corriegills.
In Bute a N.-S. crinanite dyke extraordinarily rich in fresh olivine
occurs on the road 2 miles north-east of Dunstrone; and a 3 ft. N.N.E.
dyke on the shore at Kerrytonlia is probably also a crinanite, but
contains much diffused serpentinous matter. The related olivine- —
dolerites also appear in several places. In the great Cumbrae two
crinanite dykes are known, and two of the related olivine-dolerites —
(Tyrrell, 1917). Both here and in Bute the dykes of this group
trend in a N. to S. or N.N.E. direction. On the Ayrshire mainland
crinanites are known from the shore near the Heads of Ayr.
Conctusion. — Although much still remains to be discovered
a a
oe
of the Clyde Area. 355
concerning the thousands of Tertiary dykes in the Clyde area it is
already clear that they show considerable petrographic diversity, and
that the various groups have differing relations in regard to their
size, length, direction, age, and degree of connexion with the local
centres of Tertiary volcanic activity. Only rocks of andesitie or
basaltic composition have been dealt with in this paper. There is
a well-marked division into two groups: (a) a tholeiitic group,
characterized by the presence of glass, intersertal texture, phenocrysts
of basic felspar, and presence of occult quartz; and (0d) a crinanite—
olivine-dolerite group, with coarse ophitic texture, with interstitial
analcite or radial zeolites, rich in olivine, and free from glass or
phenocrysts. The tholeiitic group ranges in chemical composition
from sub-acid types (Anderson & Radley, 1916, p. 210) to
thoroughly basic types such as those of Corrie and Largs. The
erinanite—olivine-dolerite group, however, shows no _ significant
variation, and remains uniformly basic. It is probable that other
groups will be found as investigation proceeds, especially in Arran,
where only a tithe of the dykes (and related sills) have been closely
examined. It will be necessary in future to define the relation, if
any, between the great pitchstone-felsite group of Arran and the
tholeiitic series. There may also be a relation between the crinanites
and the basalt-felsite composite sills and dykes of the south of Arran.
I must acknowledge with gratitude the assistance received in this
work from Dr. H. H. Thomas, Petrographer to the Geological Survey,
who'has not only loaned to me all the Survey slides bearing on the
subject, but has looked through many of my slides and compared the
rocks with the types occurring in Mull. I am also much indebted
to Mr. Chetai Yu and Dr. Alex. Scott for the excellent chemical
analysis of cumbraite in this paper.
REFERENCES.
ANDERSON (E. M.) and RADLEY (E. G.). 1916. ‘‘ The Pitchstones of Mull
and their Genesis’’: Q.J.G.S., Ixxi, pp. 205-17.
CLoucH (C. T.). 1897. In The Geology of Cowal, Mem. Geol. Surv.,
pp. 126-71.
FLETT (J. S.). 1911. In The Geology of Knapdale, Jura, and North Kintyre,
Mem. Geol. Surv., pp. 116-18.
GEIKIE (Sir A.). 1880. ‘‘ The ‘Pitchstone’ of Eskdale ’’: Proc. Roy. Phys.
Soc. Edinb., vol. v, pp. 219-55.
—— 1897. Ancient Volcanoes of Great Britain, vol. ii, pp. 118-80.
GEOLOGICAL SURVEY. 1914. Swmmary of Progress for 1913.
—— 1915. Summary of Progress for 1914.
HARKER, A. 1903. In The Geology of North Arran, South Bute, and the
Cumbraes, Mem. Geol. Surv., chapter on the Petrography of the Tertiary
Igneous Rocks, pp. 103-27.
—— 1908. Petrology for Students, 4th ed. (Brunton dyke).
HeEsLop (M. K.) and SmytTHE (J. A.). 1910. ‘‘ On the Dyke at Crookdene
(Northumberland) and its Relations to the Collywell, Tynemouth, and
Morpeth Dykes’’: Q.J.G.S., vol. lxvi, pp. 1-18.
SMELLIE (W. R.). 1916. ‘‘ The Igneous Rocks of Bute’’: Trans. Geol. Soc.
Glasgow, vol. xv, pt. ili, pp. 334-73.
TEALL (J. J. H.). 1884. ‘‘ Petrological Notes on some North of England
Dykes’: Q.J.G.S., vol. xl, pp. 209-47.
—— 1888. British Petrography, pp. 194-7, 200-7, pls. xii, xiv, xxiv,
ier, I Sere
356 Rev. H. N. Hutchinson—Observations on
TYRRELL (G. W.). 1909. ‘‘ The Classification of the Post-Carboniferous
Intrusive Igneous Rocks of the West of Scotland’’: Trans. Geol. Soc.
Glasgow, vol. xiii, pt. iii, pp. 298-317.
—— 1913. ‘‘The Petrology of Arran. 2. Crinanite of Whiting Bay’’:
Grou. Maa. (V), Vol. X, pp. 305-9.
—— 1916. ‘‘The Petrography of Arran. 38. Pitchstone Xenoliths in Basalt
Dyke, Dippin’’: Grou. MaG. (VI), Vol. III, pp. 193-6.
— 1917. ‘‘The Igneous Geology of the Cumbraes’’: Trans. Geol. Soc.
Glasgow, vol. xvi, pt. il.
LV.—OssprvatIons ON THE ReEcoNSTRUCLED SKELETON OF THE DrNo-
SAURIAN Reprine Dreropocus CARNEGIEI AS SEY UP BY Dr. W. J.
Hotnanp in THE Narurat History Museum 1n Lonpon, AND AN
ATTEMPT TO RESTORE IT BY MEANS OF A MODEL.
(PLATES XXII AND XXIII.)
By the Rev. H. N. HutcuHinson, M.A., F.R.G.S., F.G.S., F.Z.S., ete.
ita the following pages the writer has endeavoured to consider this
skeleton in a common-sense way, and to arrange the limbs with
reference to ordinary mechanical principles, and also by comparison
of the bones with those of different mammalian and reptilian types.
A good many years ago, Von Meyer was so struck by the colossal
and rather straight hind-limb bones of the Dinosauria and their
superficial resemblance to those of elephants, that he proposed the
term Elephantopoda; but at that time the group had not been
classified by Marsh and others into distinct sub-orders, with very
different limbs.
The writer maintains that Dr. W. J. Holland,! Professor Osborn,’
Dr. Marsh, Hatcher,? and others who are responsible for the
present reconstruction (see Plate XXII) have been, perhaps
unconsciously, influenced by Von Meyer’s interpretation, and
consequently were somewhat too anxious to produce something
very big and imposing. He has endeavoured to give a more
natural interpretation of this skeleton, and to bring it more into
harmony with other types of reptiles. The restorations by Tornier
and Holland are given in the American Naturalist, vol. xliv, 1910.
Before proceeding to discuss the details of this colossal skeleton,
81 feet long or more, it will be convenient briefly to summarize the
broad conclusions which have been arrived at.
i. With regard to the general pose of the skeleton. There are
grave reasons for considering that it stands too high.
2. The limbs, instead of being placed in a vertical plane, should
be inclined at an angle to the body, somewhat as we see in
lizards and crocodiles. Such an arrangement involves bringing
down the vertebral column into a lower position, such that the
1 W. J. Holland, Memoirs of the Carnegie Museum, vol. ii, No. 6, The
Osteology of Diplodocus, Marsh.
2 “A Review of some recent criticisms of the restorations of Sauropod
Dinosaurs existing in the Museums of the United States, with special reference
to that of. Diplodocus Carnegiet in the Carnegie Museum’’: American
Naturalist, vol. xliv, May, 1910.
* Dr. J. B. Hatcher, Memoirs of the Carnegie Museum, vols. i and ii.
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the Skeleton of Diplodocus Carnegie. 357
abdominal surface will rest not very far above the ground. The
writer has constructed a model 4 feet long in plasticine. Plate XXIII
is from a photograph ofa plaster cast from this model, which may now
be seen in the British Museum (Natural History), Cromwell Road,
S.W. Itisin the Reptile Room and under the Diplodocus Skeleton.
3. That Diplodocus was, in habit, partly aquatic and partly
terrestrial.
From Plate XXIII the reader will see the position that has been
chosen for this restoration. The tail mostly rests on the ground and
the body is horizontal, while the long neck has a slight and graceful
curve upward. A long, narrow ridge is shown on the back, which
gradually rises upward from the shoulders to the lumbar region.
The writer thinks he is justified in making this ridge, because
a ridge exists in many recent reptilian types, though of course such
appendages depend largely upon climate, etc. Lizards inhabiting
sandy deserts show a profusion of spines, scales, etc., which evidently
are protective. Even plants show a similar tendency to avoid the
chances of being devoured by hungry mammals. But we must not
assume such conditions existed, and so have dispensed with all
appendages of that kind.
‘The limbs should be quite free from the body; and any attempt to
place the femur within the body of Diplodocus as if it were a mammal
would be a fatal mistake. Dr. W. J. Holland has ventured to do so
(see his restored skeleton in the Natural History Museum and
Plate XXII).
But such interpretation is not borne out by the shape and general
plan of the femur. The writer contends that to place the limb bones
in an upright position, as in the skeleton now under consideration
(and in the restorations of Marsh, Hatcher, Osborn, and others), is
not consistent with the position of Diplodocus in the animal kingdom.
For, after all, itis a reptile. There is no getting away from that
fact: and therefore we must beware of the temptation to give any
appearance of usurping characters that properly belong to the mam-
malian class. But on the other hand, to say that it is a reptile does
not necessarily imply a belief that it crawled low down like a lizard
or acrocodile. Thesomewhat grotesque arrangement of the skeleton
shown in Dr. Tornier’s restoration is based on that view, and the
result is obviously an impossible interpretation. Nor can the writer
see his way to accept the view that Diplodocus walked in the sense
in which we apply that expression as to the mode of progression seen
in big mammals such as the elephant and rhinoceros.
According to Von Zittel, the Sauropoda display closer relationships
with Crocodilians than do the other orders of Dinosaurs, and share
a number of features in common with the Parasuchia (Belodon, etc.).
This important conclusion by such an authority must be borne in
mind in considering Diplodocus. Hence the writer feels justified
in dealing with the femur of Diplodocus, largely by comparison with
that of the crocodile.
We must try to picture something between crawling and walking,
as expressed by our restored model. ‘he relatively small size of the
pelvic girdle is, of itself, enough to remind us that, in trying to
358 Rev. H. N. Hutchinson—Observations on
form a mental picture of Diplodocus asit lived, we must constantly
bear in mind that it belongs to a rather generalized sub-order of the
Dinosauria, and that among recent reptiles the Crocodile is the
nearest thing to it.
With regard to the extremities of the limbs, the hind foot and
manus have been given positions which may be described as plantigrade
on the whole, but not so much so as the crocodile or the lizard.
The photograph of the model seen in Plate XXIII will serve to
show that the writer has endeavoured to steer a middle course between
the extreme view of Dr. J. B. Hatcher on the one hand and
Dr. Tornier on the other (see Fig. 2).
Hasirts.
With regard to the habits of this creature, there have been great
differences of opinion. The late Dr. J. B. Hatcher, whose valuable
papers on this subject the writer has read with great interest, was at
first inclined to believe that Diplodocus was an aquatic reptile, but
subsequently he somewhat modified his views, and in his latest
paper.(Memoirs of the Carnegie Museum, vol. ii) he gives reasons for
thinking that the habits of the creature were mainly terrestrial.
The present writer is not inclined to adopt this view, but considers
that Diplodocus spent much time in the waters of the rivers and lakes
in those far-off Jurassic times.
To take one reason only, it is difficult to imagine Ale great
creature supporting such a long neck and a still longer tail on dry
ground. When. standing up the strain of supporting so much weight
might become too excessive, but by taking to the water and resting
there such strain would be greatly relieved! Perhaps the shape of the
jaws and of the proximal end of the skull, which is decidedly duck-
like, helps to confirm this view. The swan has a long neck, but
gets over the difficulty by keeping it upright. This no doubt
suggested the attitude given in Dr. Tornier’s restoration of the
skeleton.
At first sight Diplodocus might possibly appear a somewhat
defenceless kind of animal, but judging from the habits of certain
living reptiles, such as the monitors, one may safely conclude that
this long tail was used very effectively as a whip whereby to lash its
enemies. Its great length is remarkable. The long neck doubtless
made a long tail desirable, otherwise Diplodocus could not succeed in
hitting an enemy trying to attack its head.
Professor H. F. Osborn in his paper on ‘‘ A Skeleton of Deplodocus ”
(on p. 14) leans to the view that Diplodocus was of aquatic habits,
holding that the tail was especially modified to function as a
swimming organ, and was provided distally with a vertical fin. He
believes the chief function of the tail to have been that of a pro-
peller to aid the animal in swimming, and that it functioned
secondarily as a balancing and supporting organ. While holding
that the Sauropoda are aquatic and quadrupedal, he infers that they
were capable of migration on land and assuming both a bipedal and
tripodal position, the tail when in the latter position functioning as
a third support in conjunction with the hinder pair of legs.
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the Skeleton of Diplodocus Carnegie. 359
It may be worth while briefly to indicate the views put forward
by Dr. J. B. Hatcher, O. C. Marsh, and Professor H. F. Osborn. As
Hatcher points out in his valuable paper above referred to, Marsh
was the first to advance the aquatic habits of Diplodocus, having
considered the position of the narial openings (nostrils) quite on the
top of the skull, as suggestive of such habits. But this conclusion,
some authorities think, is more or less shaken by the fact that certain
mammals show rather similar conditions without being aquatic.
Again, in dealing with the skeleton of Cetzosaurus, he lays stress
on the open cancellous tissue of the vertebrae and limbs. At the
time it was thought that they showed no trace of any medullary
cavity. But more recent researches have shown that some
of the Sauropoda had a medullary cavity. Dr. Hatcher thought
that, if modified at all for aquatic habits, it was in the direction
of more open and cancellous tissue, even than that which obtains
in the Cetacea, and calculated not only to give greater buoyancy
to these massive quadrupeds when in the water, but in addition to
give the greatest possible surface for muscular attachment com-
patible with the required rigidity and with the least possible weight.
In the same paper Hatcher sums up his conclusions with regard to
the locomotive powers of Diplodocus in the following words: ‘‘ That
the movements of the animal when on land were decidedly slow and
clumsy; for, had Diplodocus and its ancestors been addicted to
terrestrial life, the habitual support of so massive a body in so light
a medium as the atmosphere would scarcely have failed to produce
closely applied and well-finished articular surfaces to the limb-
bones similar to those which obtain in such members of the
Theropoda as are of undoubted terrestrial habits.”’
In his second paper (Mem. Carnegie Inst., vol. ii, p. 58) Hatcher
revises his previous. conclusions. He disagrees with Osborn’s
, conclusion about a tail-fin. The limbs, he thought, were essentially
terrestrial. They are not abbreviated or subordinated, as in the
. Amphibia and Reptilia and some aquatic Mammals. So he thinks
the limbs were first of all ambulatory to give support to the body.
He also believes his conclusions to be strengthened by a study of
the fossil remains found with Diplodocus and the nature of the rocks
in which they occur, viz. sandstones. Thus we see how the various
authorities differ among themselves. One more argument may be
mentioned here. He refers to the deeply pitted articular surfaces of
_the various parts of the appendicular skeleton (i.e. the four limbs
and the pectoral and pelvic girdles). These, he thinks, may mean
that there were thick cartilaginous pads interposed between such
surfaces at the various joints of the limbs and feet. This want of
closely-fitting and well-defined articular surfaces would appear to
afford additional evidence of aquatic habits. Here the writer would
like to point out that an animal may be very largely aquatic in habit
without showing much trace of such habit in its skeleton. For
instance, the hippopotamus, the water-rat, water-hog, otter, polar
bear, and crocodile are largely aquatic, and yet if known only by
fossil remains, would be put down as entirely terrestrial! One has
to be cautious in drawing conclusions. American naturalists have
360 | Rev. H. N. Hutchinson—Observations on
pointed out the compressed shape of the body, like that of a herring,
as confirming the evidence of aquatic habits (see Fig. 1).
Fic. 1.—Ribs of Diplodocus in position.
History oF THE SKELETON.
‘We must now consider the skeleton in detail. In dealing with
this skeleton, it must be remembered that we have before us not the
actual skeleton, but a reconstruction thereof. Each bone, as we
see it, 1s a cast made from a model, and these models are based on
several finds of Diplodocus made at different times by Marsh, Osborn, *
Holland, and others.
MareriIaLs FOR THE RECONSTRUCTED SKELETON.
Before we proceed to discuss this reconstructed skeleton, it will
be convenient to indicate very briefly the nature of the fossilized
material on which it is based. Dr. J. B. Hatcher explains in his
two valuable papers, (1) Mem. Carnegie Museum, vol.i, p.4, (2) Mem.
Carnegie Museum, vol. ii, p. 58, that his illustration of the skeleton,
as far as he knew it then, was based on two skeletons neither of
which: was complete: (1) that known as No. 84, collected by
Dr. J. L. Wortman in the expedition of 1899, and (2) another
collected by D. A. Peterson in the expedition of 1900, in the same
quarry in Sheep Creek in Albany, County Wyoming.
From a paper by Dr. W. J. Holland (Mem. Carnegie Museum,
vol. ii, p. 225), we learn that since Dr. Hatcher’s papers were
published two other imperfect skeletons have been found.
Apparently the skeleton set up in London may be taken in a general
way to correspond with the drawing in Dr. W. J. Holland’s memoir
already referred to.
the Skeleton of Diplodocus Carnegver. 361
With regard to skulls of Diplodocus, Marsh had only two. The
Carnegie Museum has a skull, but no complete skull is yet known.
We have to be content with the photographs, etc., in the paper by
Dr. W. J. Holland already referred to. The restored skull in the
reconstructed skeleton in the Natural History Museum is based on
these two skulls, but it probably will be modified when other
specimens are discovered. The vertebral formula seems to be :—
Cervicals 15, dorsals 11, sacrals 4 (or 5), caudals 35 (or 34).
Tar Posterior Liss.
We must pass on now to consider the hind-limbs. Let us take, for
example, the elephant, and see how its limbs work, comparing it
with a lizard, such as Varanus. In Elephas the femur works up
and down in a plane practically parallel with the axis of the body.
In consequence a clear space is left for it by the late dorsal ribs, for
they rapidly get shorter about midway in the region between the
pectoral and the pelvic girdles. Also this enables the elephant to
sit down with its hind-lmbs tucked away as a horse does. Now
Diplodocus could not have done this. Fig. 3 (p. 362) shows the
Fic. 2.—Posterior aspect of the pelvis and hind-limb of Diplodocus (after
Tornier).
position of the hind-limb proposed by the writer. In the case of
Varanus, alizard, we perceive something quite different; there is not
the same clear space for the movements of the femur, for the obvious
reason that the femur of the reptile, instead of working up and down
in nearly a vertical plane, works in a plane more or less horizontal,
which may be compared to the movements of an oar in a rowing boat,
while the others might be compared to a pendulum, which swings in
a vertical plane. The ribs are shortened only when quite near to
the pelvic girdle. The proximal portion of the Dzplodocus hind-limb
evidently was massive, to say the least, and the writer in his
restoration (Plate XXIII) has made it fairly big. It may therefore
well be asked how can room be found for this mass of flesh attached to
the femur and ilium except by putting the limb at an angle with
362. Rev. H. N. Hutchinson—Observations on
the body. Again, one feelsjustified in asking what evidence exists to
show that the last two ribs were really as short as those seen in the
diagram. Is it not possible that they are only based on guesswork,
and made to harmonize with the general conception expressed by the
reconstruction ?
Fic. 3.—Hind-limb of Diplodocus (after author).
The Femur.—Drawings of the femur of Dzplodocus are given in
Fig. 4. Let us examine these carefully, for it is largely from the
Fia. 4.—T wo views of left femur of Diplodocus.
I
\ t \
the Skeleton of Diplodocus Carnegier. 363
nature of this bone that the writer draws some of his chief conclusions.
The first point to which we must direct attention is that the head
of the femur is very poorly developed, as in the crocodile. Indeed,
the femur as a whole is very crocodilian—a fact which some
writers seem inclined to ignore. ‘his imperfect head offers con-
firmation of the writer’s view with regard to the arrangement of the
hind-limbs. For it seems rather obvious that, if these limbs were
intended to be upright and for walking in the manner of an elephant
or other large mammal, then we should find this head of the femur
much more fully developed—that is, rounder, larger, and more distinct
altogether. As it is we see a mere bulging out on one side of the
proximal end. How different this to the mammalian femur! But
to come back to the Dinosauria, even the huge Stegosaurus has
a more developed head to the femur. And there is good reason to
conclude that this creature used its hind-limbs for walking rather
than for crawling, and that they were set at a slight angle to the
long axis of the body, as in birds. Again, Zriceratops (von Zittel,
Paleontology, ii, p. 248, Engl. ed.) confirms our view; for its femur
shows quite a well-formed head, and this Dinosaur was much
inclined to a quadrupedal gait. ‘he writer ventures to think that
the femur of Diplodocus shows a distinct advance upon that seen in
Varanus or Crocodilus. We see the head asserting as it were a kind
of individuality. It projects distinctly from the shaft, though only
to a slight extent. We might almost be allowed to believe that
here Nature was dimly groping after the more perfect types that we
see in the Mammalia. We can well believe that this was one
reason which led Hatcher and others to place the hind-limb nearly
vertical. It is of course most essential that we should know the
true shape of this bone as well as others. Now the femur we are
dealing with is not the actual bone itself, but a reconstruction. The
only way to be sure in these matters is to go to the actual fossil
bones and see and judge for ourselves what their shapes may be.
For this purpose one must go to the Fossil Reptile Gallery of our
Natural History Museum. ‘here we see bones and casts of bones of
the Sauropoda. There isafemur of Diplodocus. It is a good deal
crushed, especially at one end. One can compare it with the
corresponding bone of Brontosaurus, Cetriosaurus, and the colossal
Atlantosaurus. The writer was greatly interested to find that the
bone is distinctly curved (see Fig. 4b). It has a double curvature.
This is a very important fact, the meaning of which must be carefully
borne in mind when one is attempting to make a restoration of
Diplodocus. It brings us back to the crocodile, and reminds us that
' we are far away from the mammalian type. ‘l’o place such a bone in
a nearly vertical plane and so imply that Diplodocus was a kind of
saurian elephant must be wrong from a mechanical point of view, as
well asanatomically! In birds, andin mammals, the head of the femur
is well developed; and the acetabulum is so shaped as to conform to
this neat spherical head, forming an admirable ball-and-socket joint,
a device well-known to the engineer, and well exhibited in man and
in birds. But among reptiles this feature is usually absent, being
only known among the Chelonia. The femur of the tortoise (or
“ie ro
364 Rev. H. N. Hutchinson—Observations on
turtle), howéver, shows only an imperfect kind of head, not nearly
a complete sphere. So with the humerus. ‘Tortoises are highly
specialized reptiles; and this contrivance is doubtless a very
necessary one on account of the weight of the carapace, for without
it the lhmbs could not perform their proper functions.
Dr. W. J. Holland and some others have been so bold as to place
the femur right inside the creature’s body, and in that way we
presume they attempt to get out of the difficulty above referred to.
But the result is certainly strange, causing Diplodocus to remind one of
a cow rather than a reptile! (see Dr. Holland’s model above referred
to). Besides, the whole shape of the pelvic girdle militates against
any such interpretation. If the femur really worked in the way
suggested by Holland and others, the writer believes that a different
shape of ilium would be necessary, viz. one more on the lines of
a mammal, that is, more outspreading.
It is very instructive to compare the hind-limb of Diplodocus and
Triceratops. Fortunately both these colossal Dinosaurs are exhibited
in the same gallery at the Natural History Museum. Consequently
the comparison is easily and rapidly made. Now the hind-limb of
Triceratops (see the writer’s Extinct Monsters and Creatures of Other
Days, now in one vol., 1911, p. 182), owing to its rather upright
position, and the ponderous nature of this Dinosaur (which probably
possessed a heavy dermal armour, at least in the writer’s opinion),
had to support a great weight. Hence the three ungual phalanges
are decidedly broad—more so than in any other known Dinosaur.’
And, moreover, that outward twist, so noticeable in Diplodocus, is
entirely absent. ‘These and other features confirm a suggestion of
the writer that Zitceratops may claim to be regarded as a reptile that
years ago played the part of a rhinoceros, i.e. foreshadowing in an
imperfect reptilian way that great and ferocious mammal! The
rather sharp and distinctly claw-like ungual phalanges of Dzplodocus
bear their testimony in favour of the interpretation of the skeleton
adopted in this paper; for with the hind-limbs set up in the vertical
plane (asin the American reconstruction) (Pl. XXI1), the downward
pressure brought to bear upon them would be so excessive that they
would probably break, or if not, they would be pressed so deep
into sand or soft earth as greatly to hinder progression on land. By
way of illustration, and to show that this conclusion is based on
reasonable grounds, let us take the case of a large dog, say a mastiff.
Leave his limbs almost as they are, but give him a heavy body with
a great massive vertebra and a long weighty tail; and then
endeavour to picture his distress in propelling along the ground this
mass of bone and flesh (even allowing for certain corresponding
increase in strength of limb)! The weight of his body would be felt
as direct downward pressure through the limbs and on to the toes.
But place the limbs at an angle to the body, and this great
pressure is relieved, because the femur—with the tibia and fibula,
with the muscles attached to them—act as a kind of spring, set
sideways to the body (see Fig. 3, p. 362).
1 Compare with foot of Hlephas.
the Skeleton of Diplodocus Carnegie. 365
Tue Tait.
The writer is convinced that no animal with such a tail as
Diplodocus possessed could possibly walk along on terra firma with
its huge body high above the ground and hmbs erect, as in the
elephant. And yet such a fact is implied by the skeleton now
under consideration. By way of homely illustration, let us try to
picture a big Monitor lizard set up on stilts as it were, by giving it
long straight limbs, and made to walk with its heavy tail at such an
angle as this great D¢plodocus tail makes with the hind-quarters.
Imagination fails! The pull of such a mass of flesh as belongs to the
anterior caudal vertebree would be prodigious! These vertebre
would require to be greatly strengthened by ossified tendons, as in
Lguanodon. But even there the pull of the tail was lessened by the
comparative lightness of the vertebree.
In all these matters the law of correlation is a useful guide,
though we admit by no means an infallible one. Ina case like this
it seems quite reasonable to make use of this guide, as Cuvier did
who first propoundedit. Looking at mammalian skeletons generally,
we seem to discover that big upright limbs and a proper quadrupedal
progression are correlated with small, light tails, as in Hlephas, Bos,
etc. Why isthis? The answer seems to be, first, that the drag of
a heavy tail would be too great, and secondly, that the limbs are
designed forrapid movement. Let us inquire whether such a deduction
is confirmed by any extinct reptile.
We return once more to the Dinosaur, which more than any other
approaches the heavy type of herbivorous mammals; and that is the
very remarkable Zriceratops which bears out in a wonderful way
Cuyier’s prophetic vision of a ‘‘ great herbivorous reptile’”’ as applied
to the famous Jguanodon. A glance at the model skeleton at South
Kensington with its huge hind-limbs shows that, instead of making
an angle with the body, they moved up and downin a vertical plane,
as in Llephas, Bos, etc., or a very nearly vertical one. So here we
actually have before us a reptile walking, as far as the hind-limbs
are concerned, after the manner of an ox! Its toes point forwards ;
and it evidently walked in true quadrupedal fashion, though perhaps
they may have had a slight inclination outwards, asin birds. And
what about its tail? The tail iscomparatively light and slender, and
quite unlike that of any other Dinosaur. And so our argument is
confirmed ; Diplodocus never had its femur working in a plane parallel
to axis of the body as in mammals.
DIscovERY OF A YET GREATER REPTILE.
Some five or six years ago, news was received of the discovery in
_ German Hast Africa of Dinosaurian bones, of the sub- order Sauropoda,
exceeding in length anything yet known even in the Western States.
Wonders never cease in the domain of paleontology. Here were
bones of such colossal dimensions as would have fairly staggered
even the late Professor Marsh! North America no longer can claim
the biggest reptile that ever walked the earth. East Africa takes
the palm. For here are bones which afford a basis of comparison of
relative sizes, and one authority has ventured to estimate the length
NG
366 ~ Rev. H. N. Hutchinson—Observations on
of this new reptile, G@zgantosaurus by name, at 150 feet! This
discovery, we think, tends to confirm the above argument with
regard to Diplodocus, its tail and its general pose; for the larger the
reptile the greater the pull of its tail on the pelvic region, to say
nothing of the strain on the legs. Besides, mathematicians now tell
us plainly that there are certain physical limitations to the size of
a terrestrial animal (see recent discussions in Vature).
By articulating limbs vertically, Hatcher and others have made
a kind of mongrel animal, part reptile, part mammal. Vature does
not mix her types; so Diplodocus must be either reptilian or mam-
malian; it cannot be both. Its upright limbs are an anomaly.
Mammals are swifter of foot than reptiles. The mammalian skeleton
is constructed for speed, and is in every way adapted for upright
limbs. The pectoral and pelvic girdles are adapted to such limbs.
This is seen most conspicuously in the humerus and the femur.
ARTICULATION OF THE VERTEBRAL CoLUMN.
A few years ago the writer, in a visit to the Berlin Natur-Kund
Museum, had the opportunity of discussing the Dzplodocus skeleton
with Dr. Brauer of that Museum. He is among those who do not
accept the interpretation of Diplodocus as represented by the skeleton
in London. And with regard to the tail, he brought forward an
argument which, as far as the writer is aware, has not been satis-
factorily answered. It is this: that several of the early caudal
vertebre have been forced into unnatural positions, as shown by the
curious angular gaps between them. This can be distinctly seen in
the London specimen. But in the restored skeleton of Dr. W. J.
Holland’s Memoir on the Osteology of Diplodocus, Marsh (Memoirs
Carnegie Museum, vol. i, No. 6), there is no sign of this want of
harmony in the arrangement of the caudal vertebre.
The present writer has also noticed that a good many of the
vertebre a little below those just spoken of show an entire want of
contact between the surfaces of the pre- and post-zygapophyses.
One would think that facts such as these might be sufficient in the
minds of unprejudiced naturalists to settle the question of the slope
of the tail, etc. But no! the American paleontologists wished this
great reptile to be as tall as they could make it. It has been
shrewdly pointed out by Professor S. W. Williston of Chicago, that
in Diplodocus, as set up in our Natural History Museum, the position
of the tail is such as to make the extrusion of an egg an impossibility!
It is not easy to conjecture what answer will be made to this
objection by other Transatlantic naturalists.
Supposing, as is likely, that Dzplodocus was partly aquatic in
habit and sought his food in the waters of rivers and lakes, one can
well imagine that such a long tail would be useful by way of
balancing the body, and especially so if at times the body was raised
up to bring the head and neck up to the surface of the waters
for respiration. Professor H. F. Osborn put forward this view in
1899 (Science, n.s., vol. x, No. 259, pp. 870-4, December 15, 1899).
But he evidently stretches this view too far in the sketch of
a model of Diplodocus standing on its hind-legs, published in the
the Skeleton of Duplodocus Carnegier. 367
Century Magazine, September, 1904. In the former one can see
clearly that Professor Osborn has disregarded the true proportions of
Diplodocus, making the neck far too long, the fore-limbs too small,
and giving it a very weak chest!
Tue Carpat anp Tarsat Bones.
If Diplodocus walked as a mammal, then we can only say that its
walking must have been of a very inefficient character. Have the
American naturalists ever considered this point—that Drplodocus
seems to possess very few wrist and ankle bones? They were
evidently largely encased in cartilage, as in living reptiles and in
all the early amphibians and reptiles. This, we maintain, renders it
quite impossible for the animal in question to have walked like an
elephant. More bones would be required in the joints to give the
necessary strength to bear so great a weight, and also to render them
sufficiently flexible their surfaces would not have been so flat. On
comparing the carpals and tarsals with those of living reptiles, the
writer finds that they approach more nearly to those of the Brazilian
tortoise than to anything else. Inthe hind-limb there is the same
fusion of several bones into one, thus forming a single bone which
probably consisted of the fibiale, intermedium, centrale, and tibiale ;
in the carpus, we seem to have the radiale and centrale combined
and perhaps the intermedium. Now, if these bones so much resemble
the corresponding bones of a tortoise, is it not allowable and reason-
able to argue that the limbs were used in the same manner, and
especially that the joints were not subjected to such extensive or so
frequent flexure as in the case of an elephant? Consider how
widely the mode of progression of a tortoise differs from that of
a mammal. The former slowly drags the limb round much as an
oarsman might slowly bring his oar forward for the next stroke, while
the elephant quickly brings it forward much as a man brings his leg
up for the next stride, and in so doing he bends the tarsal bones in
- a way that is not possible to any reptile.
But, after all, the writer would urge that perhaps the best evidence
for the view here maintained is to be found in the nature of the
pelvic girdle. Itis beyond all doubt crocodilian, and well adapted
to hold the kind of muscles required to work the hind-leg sideways
like the oar of a boat. It certainly does not possess that arching-
over shape necessary in the case of an animal that uses its hind-leg
for movements up and down like a pendulum (see p. 362, Fig. 3).
There simply is no room for the big muscles that would be required
for that kind of movement.
Tue Forz-tiuss. (Figs. 5-7.)
The writer has long maintained that the worst of all mistakes made
in the setting up of the skeleton now under consideration is the way
in which the fore-limbs are set up. It is hardly too much to say that,
in the whole animal kingdom, there is not to be found any limb
arranged in such a weird manner as this! Taking a side view of the
skeleton, one sees with positive amazement that the bones make an
368 Rev. H. N. Hutchinson—Observations on
inward curve, like a bow set up, so that its convex side points
towards the posterior end of the animal. Fig. 5 shows the articulation
proposed by the writer.
The position of the fore-limb is mechanically impossible! Such
a bow would collapse under the strain put upon it.
It is important to bear in mind that this curvature is all in one
plane, a vertical plane. There is no foreshortening or any bulging
out at an angle to the body as in modern reptiles. Now this must
be wrong. We will return to this matter later on. It is difficult,
one might almost say impossible, to conceive that such a bone was
intended to be used for movements in a direction 4B and CD parallel
with the major axis of the skeleton, as in mammals, as indicated in
the diagram Fig. 8, p. 369.
———
———
———
es >
Fig. 5, fore-limb (after-author) ; Figs. 6,7, two views of humerus of Diplodocus.
As already pointed out, that inward curve of the humerus makes it
weak. Hatcher put it the other way about. Butno bone intended to
work in such a manner would be so thin in the direction at right
angles to its movements. They are always thick in the direction in
which they are used. It must be wrong mechanically. Compare
the humerus of a dog, or rhinoceros, elephant, etc. They all have
a rounder shape which gives them the necessary strength for move-
ments in the directions 4B and CJD in a vertical plane, or, in other
words, in directions at right angles to its major axis. Now this is
just the direction in which the humerus is thinnest.
Now compare this arrangement with the posture adopted in our
restoration. The humerus now works something like an oar. Fig. 9
a
the Skeleton of Diplodocus Carnegiei. 369
shows how on the reptilian plan the movements of humerus would
follow the are 4 BC, and in this way the great breadth of this bone
would make it thick, or deep, just in the direction where strength is
required. Again, that broad spatulate end shown in Fig. 21 is really
another argument in the same direction. Looked at from a mechanical
point of view, it speaks volumes. Why should it have that large
rounded end unless its surface moved more or less in an are and
attached rather loosely to this concavity? Moreover, the glenoid
cavity, although not very well preserved, seems to exhibit a shape
more or less corresponding with such an outline (Figs. 20-3), The
crocodile’s humerus is useful for comparison.
we
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emur
\ Bune SUG
ans ads
Tibia &
| Fibula. \iie EGS.
Tail Body Neck.
Fi99. a
Fig. 8.—Diagram to illustrate wrong articulation of the limb-bones of the
Dvyplodocus skeleton. The body, neck, and tail are shortened for con-
venience.
Fie. 9.—Diagram showing working of humerus of Diplodocus (ground-plan).
As mounted, this broad, spoon-shaped blade (see Fig. 6) is placed
directly at right angles to the scapula and general direction of the
glenoid cavity. Isit likely the big musclesattached to this broadscapula
could suddenly change their direction, and somehow twist themselves
on to the humerus? ‘hey would have to pass over a long and rather
sharp ridge. And, moreover, the surface of contact is so small as to
suggest a mere point of contact and nota proper broad surface. Such
a condition is absurd and unthinkable. Bear in mind that owing to
the great weight of Diplodocus the pressure on this ridge would be
tremendous. The muscles would be lacerated and after a time
actually severed. But on the other hand, by turning humerus round
90 degrees we get a suitable broad surface to which the muscles can
be attached without violently changing their direction.
DECADE VI.—VOL. IvV.—NO. VIII. 24
370 H. N. Hutchinson—Skeleton of Diplodocus Carnegiet.
This can best be illustrated by means of a pocket-handkerchief.
Place it on an extended left arm, with part hanging over one side
near the body. Then put the right hand under it with the fingers
placed at right angles to the arm. They project in a sharp edge.
Now turn the hand round through 90 degrees of arc, and this awkward
projecting edge vanishes. It is most instructive to compare with
this the articulation seen in WVesiosaurus, Parevasaurus, Iguanodon,
Thescelosaurus, and many other forms. They all confirm the idea of
an oar, rather than a pendulum (see p. 369, Fig. 9, 4, B, c).
The writer has consulted on this point a London University
Professor of Engineering, who confirms the views here expressed.
Puystotocy A Usrerun GuIDE.
To all students of evolution it is important to bear in mind, as
a guiding principle, the one which Sir Richard Owen always kept
steadily in view, that anatomy and physiology go hand in hand.
There is a kind of correlation between them. ‘The evolutionist, in
pondering over the development of animal life on the earth from the
earliest geologic periods to the present day, perceives on reflection
that every great advance in structure is based not only on anatomical
improvements but also on physiological changes. Thus, the mammal
takes the place of the reptile in the order of evolution, and exhibits a
heart with four chambers, compared with the reptiles’ three; and the
reason for this is that the mammal is intended to win a higher place
for himself. He must be stronger and swifter, and more intelligent
than the reptile. His limbs are therefore stronger, and his brain
more active. Hence he requires an improved apparatus. Nature, the
great designer, acts in much the same way as an engineer. It is as
if an engineer had to deal with an old out-of-date motor-car. He
wants to improve it and make it run better and faster. So he takes
out the old three-cylinder engine and replaces it by one with four
cylinders. He also strengthens the chassis here and there, and thus
obtains the results that have been slowly arrived at. So nature
discarded the old reptilian heart and replaced it by one of greater
power to pump the blood to all parts of the body.
Although land mammals differ very much among themselves as
regards powers of progression, they are on the whole better endowed
for this purpose than either the amphibia or reptilia. This is largely
due to theirgreater activity associated with the relatively more efficient
circulatory andrespiratory organs. Warmand well-oxygenated blood
at a more or less constant temperature circulates freely all over the
body, endowing the limbs with considerable power of activity. A like
activity either of brain or muscle is not to be expected in the Amphibia
or the Reptilia. The skeleton of the mammal is designed with a view
to efficient walking and running. Now Dziplodocus being a reptile,
we are not entitled to expect that its limbs should be arranged on
the mammalian plan. Our study of its limb-bones confirms this
anticipation. Its character, we hope, has been vindicated; it no
longer can be said to have played a part for which it was not
intended by nature.
-
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7
Notices of Memoirs—British Association. — 371
NOTICES OF MEMOTRS.
—>—___
I.—Brirish Association For THE ADVANCEMENT OF SCIENCE.
Lonpon, Jury 6, 1917.
ADDRESS TO THE CONFERENCE oF Detueares. By Joun Hopxrinson,
F.L.S., F.G.8., F.Z.8., Assoc. Inst.C.E., President.
The Work and Aims of our Corresponding Societies.
T is nearly forty years since I suggested that the Delegates from
provincial societies should hold a Conference at each meeting
of the British Association, subsequently arranging for the first
Conference to be held at Swansea in 1880. Although sanctioned
by the Council of the Association it was not an official Conference,
being the first of five managed and supported financially by the
Delegates only. Having then been in the chair I accept with
the greater satisfaction after so many years the honour conferred
upon me to preside at the present Conference.
At the Conference held at Swansea in 1880 the following resolution
was passed: ‘‘That this Conference recommends that at future
meetings of the British Association the delegates from the various
scientific societies should meet with the view of promoting the best
interests of the Association and of the several societies represented.”
With this end in view it seems to me that Mr. Symons’ address was
particularly appropriate, for it is surely in the best interests of the
Association as well as of its Corresponding Societies that concerted
systematic work should be done.
The main object of our Societies is, or should be, to undertake local
scientific investigation, and we are here assembled chiefly to discuss
the best means of doing so and of obtaining the most valuable results.
While all should work to the same end, that end, whatever it may
be, can best be achieved by all working in the same manner, or at
least on some definite plan, so that the results may be comparable.
It is not, however, to stimulate and direct scientific investigation
only that this Conference should aim; there is also for it the wider
field of influencing public opinion on the importance of far greater
attention than at present being given to scientific education and
to many problems concerned with the future welfare of our nation in
which science may lend a fostering hand. There is no other country
in the world which has nearly so many scientific societies as we have.
There are on our list 120 Corresponding Societies (ninety Affiliated
and thirty Associated) with an aggregate membership exceeding
46,000, subject to a slight reduction, as some of these societies are
represented individually as well as by the Union to which they
belong, and some have members who are also members of other
societies on our list, but we may, I think, estimate the number
of individual members represented as not less than 45,000, while
Principal Griffiths, in his address at our Cambridge Conference, in
1904, estimated the total number of scientific societies in the
kingdom as about 500 with a membership approaching 100,000.
Tf we could all agree upon some beneficial project what an immense
influence we might have! ...
372 Notices of Memoirs—British Association—
For Section C, Geology, much good work has been done by the
Corresponding Societies, especially for the Committee on Geological
Photographs, which was formed by the joint action of the Section
and the Conference of Delegates at the Bath meeting in 1888. The
photographs (a very large number) are deposited in the Geological
Museum in Jermyn Street, where they may be seen; also numerous
lantern slides which are lent for lectures. The Committee is still in
existence and photographs are acceptable.
Other important geological subjects which have been brought before
our Conference are earth-tremors, underground water, and coast-
erosion, in the investigation of one or other of which all our
Corresponding Societies may help.
The subjects embraced in Section D, Zoology, are by far the most
attractive to members of our natural history societies, to whom
we owe nearly all our knowledge of the distribution of animal
life in the British Isles, far more perhaps of that of the Inverte-
brata than that of the Vertebrata, about which much was
known in very early days. It should be the aim of all such
societies to compile and publish lists of the animals inhabiting
their areas, recording their localities, carefully noting their habitats,
and studying their habits and life-histories. Increasing attention is
being paid to our Invertebrate fauna, but there is still very much to
be done, especially in the collection and study of the microscopic
forms of life in our rivers, lakes, ponds, and ditches, on our stately
trees and humble mosses, and even in our soils. Almost every tuft
of moist moss teems with animal life which will well repay microscopic
examination.
There is another aspect of the subject which has frequently been
brought before us, that is the preservation of our native fauna.
In endeavouring to prevent the destruction of rare animals or of
those approaching extinction all may help. We cannot well make
sure of the presence of a rare moth or butterfly without capturing it,
but there is never need to take a large series, as is the practice
of some entomologists. With birds and mammals it is different; they
can mostly be identified by the practised naturalist without shooting
them. There are birds, such as the rook and the wood-pigeon, which
should be reduced in number, as they are so destructive to our field
and garden crops, but such birds as hawks and owls, which are
persecuted by gamekeepers, are our farmers’ best friends, and their
extermination ought not to be allowed. he same may be said of all
insectivorous birds. Hawks may occasionally kill a partridge or even
a pheasant, the beautiful kingfisher may take a few fish, but the food
of the owls, with the exception of a few rare species such as the eagle
owl and the snowy owl, consist almost entirely of small rodents.’
With regard to the species which should: be protected, the
ornithologists in a natural history society can render County Councils
valuable help. An order for the protection of certain birds was
1 Taken out of a barn-owl’s tree at Keswick in Norfolk in April, 1911, were
114 ‘‘ pellets ’’ containing the skulls of 19 very small rats, 126 long- and short-
tailed field-mice, 69 shrews, and 3 small birds (perhaps greenfinches), but
no game.
“SH:
or
The Work and Aims of Corresponding Societies. 378
issued by the Hertfordshire County Council in 1895 on the
representation of the Hertfordshire Natural History Society, the
schedule being drawn up by ornithological members of the Society
and accepted by the County Council.
The subject of Museums comes, I think, most appropriately under
this Section, for they are of very great aimentonel value. One of
the most important committees of the Association was that appointed
in 1886, by the co-operation of Sections C and D and the Conference
of Delegates, for the purpose of preparing a report on the provincial
museums of the United Kingdom. ‘he Committee was very
expeditious, thanks to the energy of its Secretary, Mr. Be a Motte
presenting in the following year a valuable report which appeared in
the Report of the Association for 1887 (pp. 97-180) and a further
report the next year (Report for 1888, pp. 124-32). In the first
report there are tables (1) giving particulars of 211 provincial
museums under headings extending across two pages, (II) an
approximate estimate of the number of specimens contained in these
museums, and (III) a list of collections of special interest indicating
the museums in which they are preserved. A large portion of this
report is occupied with ‘Discussion of Details’? under thirty-six
heads. The second report considers ‘‘the ideal to which provincial
museums should endeavour to attain’, and suggests ‘‘ practical
methods for approaching that ideal”. It is not too much to say that
these reports are invaluable, not only to those who have the manage-
ment of museums, but also to all scientific workers who wish to know
where, apart from our national museums, the materials for study in
their own branch of science are to be found.
The Hertfordshire County Museum at St. Albans—the only one
with which I am connected—was not then founded, but 1 may
mention that it is visited largely by children from the Board Schools
in the neighbourhood, who take an intelligent interest in the exhibits,
quickly find out accessions, and collect and bring to the Curator
objects they wish to know the names of, presenting to the Museum
any worthy of acceptance. To young children there is one drawback
in a museum, which has been felt at St. Albans: they wish to handle
the specimens, rightly judging that by so doing they can learn more
about them than by merely looking at them. Every museum should,
if possible, have duplicates of the commoner objects, accurately
named, to lend to schools. . .
In walking over the Welsh hills I have repeatedly come across
roots and stumps of trees in the peat-mosses which frequently cover
them ; they are evidences of former forests. The land is worthless
except for the value of the peat, the removal of which would, for its
valuable products, not only as a fuel, well repay the expense, and the
ground would be rendered suitable for planting coniferous trees. It
is true that most of our peat-covered mountain-land is above the
elevation at which it is generally considered that trees will flourish
(1,500 feet), but if they did so in the past there seems no reason why
they should not do so in the future, for it is far more likely that our
climate has become warmer since trees grew on that land than it is
that it has become colder. We have also large areas of waste land
374 Notices of Memows—Tungsten Deposits of Hssexvale.
at lower elevations, extensive slopes which are too steep for ordinary
cultivation between, and on sheep-farms much very poor grazing-
land which would be more profitably used in growing timber. As to
the best trees to be planted at different elevations and on different
soils, at least by private landowners, no doubt there are many
botanists in our societies who could greatly help with their advice.
In the last half-century we have doubled our imports of timber and
now do not produce more than a tenth part of our requirements,
although our climate is admirably suited to the production of nearly
the whole.
We are far behind most European countries in the relative area of
our timbered land. For instance, nearly half the area of Russia and
of the Scandinavian countries is wooded, about 26 per cent of the
area of Germany, about 17 per cent of that of France, and the same
of Belgium, the most densely populated country in Europe until its
devastation and depopulation by the Germans, but only about 4 per
cent of the area of the United Kingdom, which will probably be
reduced owing to the requirements of our war to not more than 2 or
3 per cent.
Next to fostering agriculture let it be your aim, individually as
well as collectively in your capacity as members of societies working
in harmonious co-operation, to promote to the best of your ability the
re-afforestation of our country. By encouraging these two industries
you will help to secure its future safety and prosperity.
I].—Reporr on tHe Tunesten Deposits or Essexvate, UMZINGWANE
District. By A. E. V. Zeattny, A.R.C.8., Geologist to the
Southern Rhodesia Geological Survey.
f¥\HERE seems to be general opinion that the tungsten deposits at
Essexvale consist only of so-called alluvial or rubble wolframite,
and that reefs have not been found. This is not true. Some reefs
have long been known, and the excavation of the rubble has led to
the uncovering of others, which, so far as can be judged without
actual sampling and development, offer good prospects for mining.
But hitherto there has been a strange reluctance to undertake mining
operations on the reefs, whilst the work on the rubble has been
largely desultory.
Position.—The known tungsten reefs lie within an east and west
rectangular block of country of about 93 square miles area lying
immediately to the north of Essexvale Siding and mainly west
of the railway. The reefs extend from the neighbourhood of
‘“The Ranche” (22 miles north-west of the Siding) ‘to the Native
Church (14 miles north-east of the Siding). Sixteen distinct reefs
are known, eleven of which have had a little wes done on them
from time to time.
History.—The deposits were first prospected in 1906. In the
ensuing two years a fair amount of ore was produced, but in 1909
the production ceased. A little interest was again taken in the
deposits in 1912-13, but there was no production in 1914-15. At
1 Reprinted from the Bulawayo Chronicle of May 18, 1917.
Notices of Memorirs—Tungsten Deposits of Hssexvale. 375
the end of that period a local syndicate extensively sampled some
thousands of tons of rubble and made trial crushings. ‘lhe grade
was found to be just too low for profitable working by the methods
then employed. During 1916, however, determined efforts have
been made by other workers to test the rubble of two restricted areas.
Altogether about 85 tons of concentrate valued at £7,165 has
been marketed. The returns for 1916 are 24 tons valued at £467.
This was produced by one worker with a few natives in a five-foot
rotary diamond washer, and by one man on another claim who hand-
picked rubble and recovered 1,600 lb. of wolframite.
The prospecting done on a few reefs that have been opened has
nowhere been for more than a few feet below the surface. This may
be due chiefly to the fact that the deposit upon which serious
prospecting work has been undertaken is from its nature the least
likely to prove profitable.
Geology.—The known tungsten-bearing tract of country occupies
the central portion of an irregularly oval mass of granite about
8 miles long and 5 miles across at the widest part. ‘The long axis of
the mass trends north-west to south-east. This granite body forms
the floor of a wide depression which is traversed by two permanently
flowing streams, one of which is known as Fern Spruit. The
granite appears to pass beneath the surrounding rim of epidiorite and
felsite hills. ‘The soil is a pale-red sandy loam. ‘There are very few
exposures excepting in the streams and an occasional small but bold
granite kopje. The granite almost wherever seen is coarse-textured
and massive, that is, not schistose. It is a hornblende granite, and
is thus different from the large granite masses of Rhodesia. Patches
of epidiorite, probably inclusions of country rock, and dykes and
other bodies of felsite are occasionally encountered, particularly near
the eastern edge.
The Reefs.—The tungsten reefs consist of grevsen composed chiefly
of a soft greenish-yellow mica or of mica, fluorspar, topaz, and
. secondary felspar. This rock weathers soft and rusty brown. The
greisen has arisen by the action of vapours on a porphyry or aplite
(fine-textured white granite free from hornblende and mica). With
the greisen of each reef is a variable amount of rather white glassy
quartz forming strings or large lenses in the greisen, and evidently
connected with the greisenization, that is, deposited at the same
time and by the same agency as the mica, fluorspar, topaz, tourmaline,
chlorite, wolframite, and scheelite of the greisen.
The constant presence of the quartz lenses as part of the greisen
bodies is a great help in recognizing the presence of the greisen.
Those parts of the greisen which contain little or no quartz very
rarely crop out, and thus may easily escape discovery. No tungsten
reefs have been found without the quartz, although it is quite
conceivable that such exist.
The quartz strings expand into lenses exceeding 20 feet in width,
and thus make low hillocks such as those at ‘‘ The Ranche”’ home-
stead ; again two-thirds of a mile to the south-east of this, and at
the Native Church a mile and a half north-east of Kssexvale Siding.
The reefs vary from 200 yards to about a mile long. The two
376 Notices of Memoirs—Tungsten Deposits of Essexvale.
most promising reefs exposed are respectively about a mile long and
half a mile long so far as proved. ‘These are the Rhoda reef in the
north-eastern portion of Plot 27, and the reef running through the
Lunar and Moon blocks near the common boundary of Plots 37 and 38.
With one exception the reefs examined strike east to west and dip
north at angles varying between 30° and 55°. The reef on Plot 4
strikes north-west to south-east and dips north-east at 58°.
The width of the reefs is of course variable owing to the lenses of
quartz. Apart from the quartz lenses, the width averages three feet,
and is surprisingly constant.
In each instance the country is coarse massive hornblende granite
without signs of shearing or faulting between the reef and the
country. It appears, therefore, that the aplite was injected along
master joint planes caused by the contraction of the granite on
consolidating, and not in fissures caused by faulting. This may have
an important bearing on the persistence of the greisen bodies below
the surface. In a few instances the mica greisen has a slightly
schistose appearance. In a few places greisenization of the country
is suspected, but this is on a small scale only, and no tungsten ore -
has been discovered in it.
With the exception of the Union Jack reef in the north-west corner
of Essexvale Reserve the aplite has been completely greisenized so
far as can be judged by the small amount of reef exposed. At the
Union Jack the intrusion exceeds six feet in width, but about a third
of it consists of white aplite apparently ungreisenized.
Stockwork Deposit.—Yhe block upon which most work has been
done differs from the above blocks, which may be taken to be normal.
The occurrence in question is situated on Tungsten Kopje, a prominent
hill of massive hornblende granite with a low ridge extending about
300 yards to the east and a longer one to the west.
The fact that a large amount of float wolframite occurred
immediately around the hill led to prospecting on the hill, with the
result that a stockwork deposit was discovered extending along the
eastern and western ridges and on the north flank of the hill.
Throughout the massive hornblende granite of this zone streaks
and seams of aplite containing gashes of quartz are scattered rather
sparsely and quite indiscriminately. ‘These seams run in all directions
and at all angles, many are nearly flat, but some are vertical; they
make small saddles in several places, but pursue irregular courses, and
expand and die out quite irregularly. They average a few inches wide
and in no instance exceed a foot. None are traceable for more than
afew yards. The greisen always carries streaks of quartz and occurs
on one or both sides of the latter. ‘The aplite varies in degree of
greisenization. In some parts the greisen consists of sugary quartz
and pyrite with very fine wolframite scattered through it but invisible
to the naked eye. Such a rock weathers brown and strongly
resembles sandstone. It is always present in the rotary concentrate.
In other parts the greisen consists chiefly of a soft yellow mica.
At the south-west end of this deposit a body of greisen about
6 feet wide, striking north to south and dipping about 40° E., has
been opened and afforded rich patches of wolframite.
Notices of Memoirs—Tungsten Deposits of Essexvale. 377
Minerals of the Greisen.—The minerals detected in the greisens
comprise quartz, soft yellow mica, felspar, dark-green chlorite in
rosettes, black tourmaline, pyrite (altered to cubes of limonite at the
surface), fluorspar (blue, mauve, green, white, and colourless), topaz
(pale brown and colourless), galena (rather rarely), pyrrhotite,
wolframite, and scheelite.
Small quantities of each of these occur in the quartz. Here and
there a bunch or streak of any one of them, including the tungsten
minerals, les in the quartz. The distribution of the minerals in the
quartz or in the altered aplite is in fact generally patchy, as is always
the case in greisens. Coarse aggregates of any one mineral are
occasionally noted; for example, single aggregates of very large
wolframite crystals weighing 235 and 157 lb are said to have been
found at the stockwork deposit, and similar groups of crystals have
been obtained at the Lunar Block (the specimen in the Rhodesia
Museum weighing 172 lb. came from here). Pieces of wolframite
weighing up to 8 lb. are not uncommon, and groups of pale pinkish
scheelite crystals measuring 8 or 4 inches are to be found. The two
tungsten minerals are commonly intergrown; butin spite of this and
of the fact that scheelite, containing as it frequently does several per
cent more tungstic oxide than wolframite, may be worth several
pounds sterling per ton more than the wolframite, it was found that
the scheelite was neglected by the workers; in fact, considerable
trouble was taken by them to separate it from the wolframite and
reject it.
Scheelite is a mineral very easily recognized, and the natives
engaged in panning the concentrate should be taught to know it.
Although it is not unlike quartz so far as colour is concerned—being
white, pinkish, or yellowish—its characteristic greasy lustre, softness
(at is easily scratched by the knife or by quartz), and heaviness are
properties which differentiate it sufficiently from any of the minerals
with which it is associated. If boiled in dilute hydrochloric acid it
. becomes coated with bright yellow powder soluble in alkali.
Among the dark minerals got in the concentrate, magnetite may be
recognized (and separated) by the magnet, and limonite by being in
brown cubes. Coarse and moderately ‘fine wolframite is aril
distinguished from the other black minerals by its greater specific
gravity and chocolate-brown streak; it breaks into flat slabby pieces
with lamellar structure owing to the presence of a single perfect
cleavage; the flat surfaces are bright and shiny (submetallic to
resinous lustre), whilst the cross fractures aredull. Ilmenite, which
is rather abundant in very fine round grains in the concentrate of the
rubble, is difficult to distinguish from fine wolframite by simple tests,
and this fact had led to the rejection of the finest concentrate. —
Mineralization —In addition to the minerals common to greisen,
the presence both in the stockwork and in the veins, of galena,
pyrite, pyrrhotite, and presumably gold, together with the large
amount and constant presence of a kind of quartz which is indis-
tinguishable from the ordinary vein quartz of gold deposits, suggests
that the Essexvale tungsten deposits are not normal greisens, but to
some degree assume the characters of the gold-quartz vein type of
o) WS We whe
> (ris, ited
hav We
’
%
378 Reviews—Butler’s Handbook of Minerals.
deposit. In fact, they appear to form a connecting link between the
two types. This theory is borne out by the character of the
mineralization of the country rock alongside the greisen streaks in
the stockwork deposit. The rock is pyritized (pyrite and pyrrhotite),
and the felspars altered to sericitic aggregates.
The Rubble.—The richer patches of rubble lie within 100 yards of
the greisens on the steeper ground and within about 25 yards on the
flat ground.
Tests of this rubble indicate that the yield of wolframite (the
scheelite as noted above being rejected) varies from 2 to 8 lb. per ton.
In this estimate the occasional lumps of coarse wolframite are not
included, and fine wolframite and scheelite in lumps of rock and free
are also not included, since they are rejected.
In the instance of the western end of the Lunar Block reef it was
stated that early in 1916, 1,600 lb. of wolframite was picked up from
the surface by hand without any appliances, without even a prospecting
pan, notwithstanding that the ground had been broken, turned over,
and picked on at least one previous occasion.
' Where the rubble is being more thoroughly tested, the ground,
made up of angular quartz fragments, brown-weathered greisen, and
sandstone-like aplite in a matrix of red loam, is hand-jigged on
rocking-screens, the coarse wolframite being hand-picked from the
screens. The fines are concentrated in a 5 ft. rotary diamond
washer, which recovers the tungsten minerals and even the fine heavy
minerals. The concentrate is then panned by hand. The coarse
wolframite (pieces over half aninch) are picked by hand and the fines
re-panned. Any coarse wolframite with adhering quartz is pestled
and panned. The coarse and medium concentrate so obtained is
remarkably clean wolframite. The finest concentrate consists of
wolframite and scheelite, with a certain amount of quartz, felspar,
epidote, hornblende, mica, zircon, and tourmaline, together with
a trace of gold, and a fairly large quantity of ilmenite, limonite
cubes, and magnetite. The finest concentrate is rejected under
existing circumstances, but on a larger scale of operations concen-
trating tables and magnetite separators may be expected to give
profitable results. :
REVI ws-
I.—A Pocket Hanpzoox or Miyerats. By G. Monracur Burter.
Second Edition. pp.x -+ 311, with 89 figures in the text. New
York, John Wiley & Sons; London, Chapman & Hall, Ltd.
No date. Price 11s. 6d. net.
HIS handy little treatise by the Professor of Mineralogy and
Petrology in the University of Arizona has met with such
a large demand that a second edition has been called for. The
original scope and plan proved so satisfactory that no change as
regards them was made, and the only difference in this edition is
that additions have been made here and there to the original text __
where experience has suggested the need, and, of course, all. —
typographical errors that have come to light have been corrected.
Reviews— Fossil Beetles fron Colorado. 379
The mineral species are arranged in the customary order, and are
described concisely, but sufficiently fully for the purpose of
discrimination. Happy use has been made of heavier type to
emphasize the more important or prominent features. Under each
we find particulars of the chemical composition, hardness, lustre,
colour, streak, cleavage (if any), transparency or opacity, specific
gravity, simple blowpipe reactions, and crystal form. We may
throw out the suggestion that now that portable, trustworthy
refractometers are available, it would be advantageous in a subsequent
edition to include details of the refractive indices and of the double
refraction where it is present. In the case of a transparent substance
a measurement of the refractivity will often settle its identity
beyond doubt. The blowpipe reactions are such as can easily be
carried out with an ordinary portable outfit. ‘I'o facilitate the
determination of mineral specimens, the more obvious physical
characters are tabulated at the end of the book on a series of folded
leaves; by consulting this table the inquirer may reduce the
number of species to which a particular specimen might belong to
two or three, and a reference to the fuller descriptions in the text
will lead to the proper identification.
As a help to the prospector Professor Butler in a series of
appendices gives the retail prices of good to very fine cut stones, the
value of metals and minerals, a glossary of the technical terms and
expressions used in the description of minerals, a table of the
elements with their symbols and atomic weights, Mohs’s scale of
hardness, and von Kobell’s scale of fusibility. The information
given in the first appendix on the charges made by lapidaries for
cutting stones is not sufficiently explicit. In the case of ‘‘ fancy ”’
stones the cost of cutting is based on the weight of the finished
stones, whereas for diamonds it is the weight of the rough material
that determines the cost, and the charge for faceting a diamond
works out at more than fifteen times what it would be for an
ordinary stone of similar size when cut. Few lapidaries undertake
both classes of work. The author seems to be unaware that the
standard weight practically all over the world is the carat of
one-fifth gram, and not as defined by him. He points out in a note
to the second appendix that the quotations for metals and minerals
are those prevailing before the War; inasmuch as the large increases
now obtaining will probably in most instances end with it, he has
refrained from giving them. The publishers are open to severe
criticism for their omission to give any indication of the date of
publication ; it is only the fact that the author in this note speaks of
the ‘‘ Kuropean’’ war that any clue as to the date is afforded. The
curious use of two very different kinds of paper militates against the
appearance of the book.
Ii.—New Srrcres or Fossrz Berries From Frorissant, Conorano.
By H. F. Wicxnam. Proc. United States National Museum,
1917, vol. lii, pp. 463-72, pls. xxxvii-ix.
OME fifteen new species are described and figured under almost
as many genera, Brachyspathus being new, while all are
380 Reports & Proceedings —Geological Society of London.
comprised in the following families: Carabide, Coccinellide,
Buprestide, Sampyride, Malachiide, Ptinide, Spondylide, Ceram-
bycide, Bruchide, Otiorhynchide, and Curculionide.
III.—The Zoological Record, vol. lii, for 1915, has recently appeared
and contains as usual papers on fossil as well asrecent zoology. The
volume for 1916 is in hand, and may be expected this time next
year. he book is thinner than usual owing to the dearth of work
and the difficulty of obtaining that from enemy countries. It is on
sale, in the special parts, at the Zoological Society of London.
LV.—Wuiram Smiru: uis Maps anp Memorrs.
NHE story of William Smith, “the Father of English Geology ”
as he was styled by Professor Sedgwick long ago, has been told
by his nephew, the late Professor John Phillips, by H. Woodward,
Professor J. W. Judd, Mr. Sheppard, and many others (see Gzot.
Mac., 1869, 1870, 1873, 1877, 1892, 1897, etc.). Mr. Sheppard has
recently described his maps (see Proc. Geol. Soc. Lond. in Gxot.
Mae., July, 1917, pp. 330-1). Now some 200 pages and 17 plates
are issued in the Proc. Geol. Soc. Yorkshire for March, 1917.
In this elaborate and carefully prepared work, Mr. T. Sheppard
presents, in a graphic manner, Smith’s career, his special work in
Yorkshire, the history of maps, personal memorials, ‘‘claims’’ now
first made public, and several of his manuscript memoirs. Besides
this the author discusses earlier work on mapping by Owen, Lister,
Strachey, Woodward, Desmarest, Pache, Michel, Whitehurst,Smeaton,
the Board of Agriculture, Tiantesont ee wkinson, and all Smith’s maps
in detail, so a fairly comprehensive view of this subject is unfolded.
The illustrations are admirably selected for their purpose, and the
paper (published at 5s.) should be in the hands of every geologist.
REPORTS AND PROCHEDINGS.-
I.—Gerotoetcat Socrrry or Lonpon.
June 20, 1917.—Dr. Alfred Harker, F.R.S., President, in the Chair.
The following communications were read :—
1. ‘‘The Pre-Cambrian and Associated Rocks of the District of
Mozambique.” By Arthur Holmes, A.R.C.S., D.I.C., B.Sc., F.G.S.
Beyond the coastal and volcanic beds of Mozambique (described in
a previous contribution—Abs. Proc. Geol. Soc. 1916, No. 994, p. 72)
the country assumes the form of a gently undulating plateau,
gradually rising towards the west and diversified by innumerable
inselberg peaks and abruptly rising clusters of hills. The dominant
rock throughout is a grey biotite-gneiss. Interfoliated with this
are occasional lenticular masses of hornblende-gneiss and amphibolite,
and within these smaller bands of crystalline limestone are sometimes
preserved. In many places the gneisses become garnetiferous, while
eclogites and basic granulites also occur. Schists—referable to
arenaceous sediments—are found only near the coast, where they are
i
:
Reports & Proceedings—Geological Society of London. 381
interbanded with gneisses; and, as the latter are mainly of igneous
origin, they are thought to be intrusive into, and therefore younger
than, the schists. Asa general rule, the foliation and the banding of
the gneisses are well defined in parallel uncontorted planes, the
strike being commonly along, or somewhat north of, a north-east
to south-west direction. In certain inselberg peaks, the strike sweeps
round the contours, while the foliation surfaces dip quaquaversally
from the summit. Into the gneisses later granites, belonging to at
least two different periods, have penetrated, riddling them with
enormous numbers of small intrusions, lit-par-lit injections, tongues,
and apophyses. Rocks of later age are rarely met with; but in
a few places dykes of picrite and pyroxenite have been found cutting
the youngest pegmatites.
The succession of rocks in eight of the better-known districts is
described, and the following general classification is based on the
details thus provided :—
Ultrabasic { Pyroxenites. Nixes eee
Dykes. Picrite. foe eee
Intrusive Contact.
Granites and {Biotite-Granites. Pre-Cretaceous
Coarse Graphic Granite and other Pegmatites. ; and Post-Middle
Pegmatites. | Quartz-Veins. Pre-Cambrian.
Intrusive Contact.
Ce aenalitic Be Craniues (including Porphyritic,
Granites WED AIS) ; :
aes Pegmatites and Aplites. Middle
Pegmatites, , yy: = é
ail SSE | Pyroxene-Granite and Quartz. Pre-Cambrian.
: Ro k avec} Pyroxene-Diorite Series. Pb/U =0-14-0-17.
acre Pyroxene-Granulites ?
Intrusive Contact.
Biotite-Gneisses and
Gneisses Gneissose Granites.
and Hornblende Gneisses. Pb/U=0-21.
Associated | Amphibolites.
Rocks. Garnetiferous Gneisses,
Granulites, and Eclogites.
: Lower
Intrusive Contact. PraCiine
Quartz-Mica-Schists.
| Quartz-Magnetite Schists,
ee He Hornblende-Garnet-Schists.
Tee | orsterite Stare
* | ¥Forsterite Marbles, and other
Crystalline Limestones.
The above correlations of certain groups of rocks with the
Lower and Middle Pre-Cambrian of other regions are based on
the determination of lead-uranium ratios of zircons derived from the
eneisses and granulitic granites respectively, the zircons having been
obtained by crushing and panning the rocks in the field. The
gneisses give a ratio of 0-21, comparable with a ratio of 0:24 obtained
for Canadian zircons of Laurentian age. The granulitic granites
give ratios of 0°14 to 0°17, comparable to those of radio-active
382 Reports & Proceedings—Geological Society of London.
minerals of late Archean, that is, late Middle Pre-Cambrian, age in
Scandinavia (Moss 0°12 to 0:15, Arendal 0-16 to 0°18, and Ytterby
0:15 to 0°17), Canada (Villeneuve, Quebec, 0°17), and India
(Singar 0°14).
The rocks are described in detail, with tables giving the
quantitative mineral composition and the specific gravities and
radium contents. Numerous examples of contact phenomena between
crystalline limestones and various types of igneous rock are recorded :
pyroxene, amphibole, sphene, and soda-lime felspar being the new
minerals chiefly developed, between granite and limestone, with
garnet and scapolite in special cases.
With reference to the origin of the crystalline limestones and
gneisses the following conclusions are arrived at :—
(a) The crystalline schists and limestones are interpreted as arenaceous
and calcareous facies of an ancient sedimentary series, their
argillaceous complements being unrepresented unless they enter
into the composition of the biotite-gneisses.
(b) The limestones have controlled the formation of hornblende-gneiss
and amphibolite by their interaction with a granitic magma that
elsewhere is represented by biotite-gneisses. The cores of the
limestones have been enabled to resist further silicification by being
thus enclosed within a blanket of rocks impoverished in silica.
(c) If the ancient sedimentary series included argillaceous formations,
it is thought probable that the gneisses are composite rocks
produced by the concordant injection of granitic magma into
such formations. This view, although not proved, is supported
by mineralogical and radio-active evidence, and by the fact that
in certain inselberg peaks the banding of the gneisses gradually
dies away as the slopes are ascended, the rocks passing into
granulitic granite nearly free from biotite and showing few traces
of foliation. These peaks are interpreted as the irruptive foci of
granulitic magmas which fed the lateral intrusions represented by
the surrounding gneisses.
It is shown that there are at least three types of inselberg peaks
that owe their survival to peculiarities of structure and composition.
The first type is that just mentioned, in which the foliation is less
marked and the biotite content appreciably lower than in the
surrounding gneisses. In the second, the peaks are mainly composed
of granulitic granite (again poor in biotite compared with the
gneisses), and in the third type the peaks are riddled with tongues
and apophyses of pegmatite and aplite. In each case the greater
resistance offered to denudation is related to the presence of less
foliated and more felsic rocks than are found in the adjacent plains.
There remains a fourth type—perhaps the most abundant—in which
no differences have been recognized. Many of these seem to be
isolated relics of gneissic escarpments; and it is suggested that desert
erosion, involving the attack of slopes at their base by arid
weathering, and the removal of disintegrated material by wind, is
the most favourable condition for the development and maintenance
of an inselberg landscape. Existing conditions of denudation are
considered to be unfavourable to inselberg survival; for the peaks
appear to be worn down by the removal of superficial layers by ex-
foliation more rapidly than the surface of the plateau is lowered.
eae i via ees Carsten |
Reports & Proceedings—Geological Society of London. 388
_ 2. ‘The Inferior Oolite and Contiguous Deposits of the Crewkerne
District (Somerset).”” By Linsdall Richardson, F.R.S.E., F.G.S.
In this communication a detailed description is given of the Inferior
Oolite of the Crewkerne district.
Roughly speaking, the Upper Liassic Sands to the south-west of
a line connecting South Petherton, Crewkerne, and South Perrott,
are very similar to their equivalents in the Burton—Bradstock—
Beaminster—Broadwindsor district. ‘To the north-west of that line,
however, limestones—largely made up of shell-débris—replace
a considerable portion of the yellow sands of moore? hemera,
‘‘thickening”’ from about 18 feet at North Perrott (‘‘ Perrott Stone’’)
to 78 feet at Ham Hill (‘‘ Riddings” and Ham Hill Building-Stone).
In the extreme south-western portion of this district, around say
Drimpton, the Aalensis beds are also probably very similar to their
equivalents in the Burton—Bradstock—Beaminster—Broadwindsor
district, and at Furzy Knaps, near Seavington St. Mary (4 miles
north-west of Crewkerne), what is seen of them is highly fossiliferous.
Hast of Crewkerne, however, these beds ‘‘attenuate’”’ and “‘ die out”
altogether between North Perrott and Yeovil Junction.
The Opaliniforme beds at Broadwindsor, Whaddon Hill, and
Chideock Quarry Hill comprise, in descending order—
(a) Rusty Bed ;
(b) Very fossiliferous sandstone ; and
(c) Sands and sandburrs.
The equivalent of (0) is readily recognized at the Cathole Lane
Section, Crewkerne, where it is very rich in ammonites. Above it
are deposits which are with but little doubt equivalent to the Rusty
Bed of moresouthern localities. East of Crewkerne, the Opaliniforme
beds—like the Aalensis beds — “attenuate,” the lower beds
apparently disappearing first. . They ‘‘die out’’ between Kast
Chinnock and Yeovil Junction.
The Sczssum beds are 6 ft. 2in. thick at Broadwindsor, and
very fossiliferous. They retain the characters exhibited at Broad-
windsor in the area south of the L. & 8.W. Railway; but at North
Perrott, on the north, what appears to be the equivalent of their
lowest portion is softer and thicker. The Scisswm beds also fail
between Kast Chinnock and the Junction.
The Sczssum beds are succeeded by the Ancolioceras beds—at the
Conegar Hill Section, Broadwindsor, two strata, each 1 foot thick.
The Ancolioceras beds extend into the Crewkerne district: they are
well exposed at the Misterton Lime-works and at other sections in
the neighbourhood, and apparently were proved in the now filled-up
_ quarry in Haselbury Plucknett village. Probably the Ancolioceras
beds persist throughout the Crewkerne district.
The upper portion of the 2lurchisone beds is the main horizon for
Zeilleria anglica (Oppel). In the neighbourhood of Beaminster
specimens of this Brachiopod are very abundant. The true Zeclleria
anglica beds are absent from the Conegar Hill Section, but occur at
Drimpton, in the extreme south of the Crewkerne district, and
apparently were met with at Haselbury Plucknett, east of
Crewkerne.
384 Reports & Proceedings—British Association.
Attached here and there to the top of the Wurchisone—Ancolioceras
beds is ironshot rock, doubtless of late bradfordensis date—the date
ot the Rhynchonella ringens beds of the Sherborne district. Thicker
deposits may be present at Dinnington and Haselbury Plucknett.
Deposits of concavi, discite, and, in places, of blagdeni hemerze may
also be present in the neighbourhood of Dinnington.
There is thus a great hiatus in the Inferior Oolite Series of the
Crewkerne district, there being—except possibly in the neighbourhood
of Dinnington—no rock present assignable to any hemera between
those of bradfordensis and garantiane—the latter the date of the wide-
spreading Upper Zrigonia Grit of the Cotteswolds.
The rock of garantiane date varies considerably in lithic characters,
thickness, and abundance of organic remains in the district.
It has not been possible to identify definitely the Zruellec bed in
the district. The main of the Top Limestones is of schlenbachi date.
The Schlenbachi beds ‘‘attenuate’’? east of Crewkerne; but at
Haselbury Mill Quarry, in what the author regards as their lower
portion, is a very interesting Sponge Bed, similar in appearance to
that exposed in the Peashill Quarry, Shipton Gorge (Dorset). This
Sponge Bed is rich in microscopic organisms. The Zigzag bed (very
similar in its equivalent in the Burton—Bradstock—Beaminster—
Broadwindsor district) has been observed at North Perrott and
Haselbury Mill Quarry.
The Scroff (fusce hemera) was apparently observed by J. F.
Walker in a quarry near Misterton Church. Fullers’ Earth Clay
succeeds the Scroff.
IJ.—Bririsu AssocraTION FOR tHE ADVANCEMENT OF SCIENCE.
After consultation with members of H.M. Government and with
the local authorities at Bournemouth the Annual Meeting of the
British Association, which was to have been held at Bournemouth this
year, has been cancelled; but the General Committee met in the
Rooms of the Linnean Society, Burlington House, Piccadilly, London,
on Friday, July 6, at 12 noon, and received the Report of the Council,
and elected Officers of the Association and Members of the Council.
Meetings of the organizing committees of the various sections, the
delegates of corresponding societies, the committee of recommendations,
and the general committee have therefore been held. It has been
decided to continue Sir Arthur Evans in the presidency for another
year, while Sir C. A. Parsons, who would have presided over this
year’s meeting, will do so at the meeting which it is hoped will take
place as arranged at Cardiff next year. The meeting this year would
have been at Bournemouth, and that borough hasrepeated its invitation,
which has been accepted, for 1919. Grants amounting to £286 were ©
made in aid of such researches as were regarded as essential to carry
on, having regard to present conditions. The new members of the
Council of the Association are Dr. KE. F. Armstrong, Mr. J. H. Jeans,
Professor A. Keith, Professor W. H. Perkin, and Mr. W. Whitaker.—
From the English Mechanic, July 20, 1917.
LIST OF BOOKS OFFERED FOR SALE
AT THE NET PRICES AFFIXED BY
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BAYLEY (W. S.). Minerals and Rocks: the Elements of Mineralogy and
Lithology for the use of Students in General Geology. London, 1916.
pp- vili + 227. 8vo. Illustrated. Cloth. 6s,
FERGUSSON (W. N.). Adventure, Sport, and Travel on the Tibetan
Steppes. London, 1911. 8vo. With illustrations from photographs by
the Author and the late Lieut. Brooke, and two maps. 8yo. Cloth
(16s. net). 5s. 6d.
GUPPY (H. B.). Plants, Seeds, and Currents in the West Indies and Azores ;
the results of investigations carried out in those regions between 1906 and
1914, London, 1917. Royal 8vo. Cloth. £1 5s.
—— Observations of a Naturalist in the Pacific between 1896 and 1899.
Vol. I: Vanua Levu, Fiji, a description of its leading Physical and
Geological Characters. Vol. IL: Plant-Dispersal. London, 1903-10.
2vols. 8yvo. Illustrated. Cloth (36s.). 10s. 6d.
HERMAN (0O.) anD OWEN (J. A.). Birds Useful and Birds Harmful.
Manchester, 1909. pp. vili + 387, with numerous illustrations. 8vo.
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KEITH (A.). The Antiquity of Man. London, 1915. 8vo. With 189
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LEITH (C. K.) anpb MEAD (W. J.). Metamorphic Geology. A Textbook.
New York, 1915. 8vo. Illustrated. Cloth. 12s.
MARR (J. E.). The Geology of the Lake District and the Scenery as influenced
by Geological Structure. Cambridge, 1916. 8vo. With geological
map and figures. Cloth. 12s
MURDOCH (J SE Microscopical Determination of the Opaque Minerals: an
aid to the study of Ores. New York, 1916. pp. vii+ 165. 8vo. Cloth.
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OSBORN (H. F.). Men of the Old Stone Age ; Environment, Life, and
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RASTALL (R. He): Agricultural Geology. Cambridge, 1916. pp. 340. S8vo.
Illustrated. Cloth. 10s. 6d.
| SEWARD (A. -C.). Fossil Plants: a Text-book fos Students of ene and
Geology. Vol. iii. Cambridge, 1917. 8vo. With 253 illustrations.
— — Cloth. 18s. (Vol. i, 1898, 10s.; Vol. ii, 1910, 15s.)
TILLYARD (R. J.). The Biology of Dragon-flies (Odonata or Paraneurop-
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and text illustrations. Cloth. 15s.
WAGNER (F. H.). Coal and Coke. New York, 1916. pp. 431, 8vo,
4 with 137 Illustrations. Cloth. 17s.
| WEST (G. S.). Alge. Vol. I: Myxophycex, Peridiniew, Bacillariex,
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distribution of Freshwater Alosz. Cambridge, 1916. pp. 486. Royal 8vo.
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No. IX.—SEPTEMBER, 1917.
ORIGINAL ARTICLIHS.-
Race Ses
I.—Norrs on THE Pycnopont Fisuxs.
By Agtuur Smith Woopwarp, LL.D., F.R.S.
(PLATE XXIV.)
fJ\HE Pycnodonts were the coral fishes of Mesozoic seas, with
a deepened body, produced face, and a small mouth having
grasping and grinding teeth, capable of obtaining their hard-shelled
~ food from hollows and crannies. They are evidently not to be
regarded as closely allied to any of the typical coral fishes of Tertiary
and existing seas, which are spiny-finned teleosteans. They are
merely Lepidotus-like and Dapedius-like forms with adaptations to
a similar mode of life. ‘The study of their skeleton is therefore of
great interest.
A complete summary of the osteology of the Pycnodonts, so far as
known, was published in 1895-6'; and, following the observations
of other authors,” I have since had many opportunities of pursuing
_ the subject further. A detailed study of Microdon radiatus in the
forthcoming part of the Monograph of Wealden and Purbeck Fishes
for the Paleontographical Society has especially led me to review
the whole group of Pycnodonts, and I now venture to publish a few
supplementary notes which these researches have suggested.
The normal arrangement of the roof-bones in a Pyenodont skull
is shown in the accompanying restoration of M/esodon (p. 386). An
elongated unpaired plate—the so-called supraoccipital (s.occ. )—forms
the median ridge behind, and completely separates a pair of plates
which are commonly identified as parietals (pa.). Hach of the latter
seems to represent a true parietal fused with a supratemporal; for
in Microdon radiatus, at least, it is clearly traversed behind by two
parallel transverse slime-canals. The bone also bears at. the middle
of its hinder border a smooth process with digitate end, which passes
1 A. S. Woodward, Catalogue of Fossil Fishes in the British Museum,
pt. ii (1895), pp. 190-8 ; also ‘‘ On some Remains of the Pycnodont Fish,
Mesturus, discovered by Alfred N. Leeds, Esq., in the Oxford Clay of
Peterborough”: Ann. Mag. Nat. Hist. [6], vol. xvii (1896), pp. 1-15,
pls. i-iii.
2D. G. Kramberger, ‘‘De Piscibus Fossilibus Comeni, ete. ”: Djela
Jugoslav. Akad., vol. xvi (1895), pp. 18-34, pls. v-vii, fig. 1. E. Hennig,
‘*Gyrodus und die Organisation der Pyknodonten”: Paleontographica,
vol, liii (1906), pp. 137-208, pls. x-xili; also ‘‘ Ueber einige Pyknodonten
vom Libanon”: Centralbl. fiir Mineral., 1907, pp. 360-71.
DECADE VI.—VOL. IV.—NO. IX. 25
7 } am bs ‘.
: i hs ) ‘ As
aa
396 Dr. A. Smith Woodward—Notes on Pycnodont Fishes.
beneath the antero-dorsal scales, and may perhaps be regarded as the
post-temporal. It is, at any rate, noteworthy that in Gyrodus, where
separate supratemporals and post-temporals appear to be recogniz-
able,! the parietal is exceptional in lacking the small posterior process.
The otic region is completely covered by a squamosal plate (s9.).
|
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Mesodon macropterus (Agassiz) ; restoration, with cheek-plates removed,
about two-thirds nat. size. Upper Jurassic (Lithographic Stone) :
Bavaria. fr. frontal; m.eth. mesethmoid ; md. mandible, showing
narrow dentary in front; op. operculum ; orb. orbit; p.op. pre-
operculum ; pa. parietal ; pas. parasphenoid ; pmax. premaxilla ; 8.occ.
supraoccipital ; sq. squamosal; v. vomer. Drawn by Miss Gertrude
M. Woodward, chiefly from a specimen in the British Museum
(No. P. 5546).
The frontals (fr.), which meet in a median suture, are the largest
bones of the roof, sometimes ending abruptly just in advance of the
orbit, sometimes tapering along the upper edge of the mesethmoid
element of the snout. 3
1 B, Hennig, Paleontographica, vol. li (1906), p. 143, pls. x, xi. ‘Ve
Dr. A. Smith Woodward — Notes on Pycnodont Fishes. 387
In Mesodon, Microdon, Stemmatodus, Gyrodus, and DMesturus, the
roof-bones form a continuous shield; but in Celodus, Pycnodus, and
perhaps Palgobalistum, there is a small supratemporal vacuity on
each side, bounded in front by the frontal, mesially and in part
posteriorly by the ‘‘ supraoccipital ’’, laterally and in part posteriorly
by the ‘‘parietal’’. In the British Museum this vacuity is well seen
in specimens of a new species of Celedus from the Lithographic Stone
of the Montsech, Lérida, Spain (Nos. P. 10999, 11000), in Celodus
coste from Castellamare, Italy (Nos. P. 1671, 1671a), in the so-called
Paléobalistum ponsorti (which is probably a species of Pycnodus) from
Mont Aimé, Marne, France (Nos. 28292, P. 1638), and in Pycnodus
platessus (No. P. 1633) and P. gibbosus (No. P. 1634) from Monte Bolea,
Italy. It evidently corresponds with the supratemporal vacuity in
the existing teleosteans of the family Zeide,! and implies that in the
Pyenodont genera just mentioned the lateral muscles of the trunk
extended slightly forwards over the cranial roof. The ‘“ supra-
occipital” is therefore probably the foremost dorsal ridge-scale
enlarged and displaced forwards, while the part of the “parietal ”’
bounding the vacuity behind is really a supratemporal.
The delicate and toothless pterygoid arcade, which was first seen
in Anomeodus and Mesturus, has now been observed both in Gyrodus
and Celodus; but the nature of the palatine bone remains uncertain.
In the tritoral dentition there is still no satisfactory evidence of
successional teeth. ‘There are usually only two prehensile teeth in
each premaxilla and dentary; but both in Gyrodus and in Mesturus
there are three or four teeth in the premaxilla, four in the dentary.
Although the dentition is obviously adapted for crushing hard
skeletons, it is curious that no example of a Pycnodont has hitherto
been described showing the contents of the stomach. There appears
to be only one such specimen in the British Museum—a small
individual of Pycnodus platessus, shown of the natural size in
Plate XXIV. Here the distended stomach is filled with the
comminuted remains of bivalved shells, which are ornamented with
radiating riblets, but are too imperfect for determination.
In this connection it is interesting to notice that some of the
Pycnodonts agree with the existing Balistes in possessing clusters of
small claw-shaped pharyngeal teeth. These teeth, found isolated,
are known to paleontologists under the name of Ancistrodus.* In the
British Museum I first observed them in their natural position in
specimens of Calodus from the Montsech, Spain (No. P. 10996). They
are seen in nearly all specimens of Paleobalistum ponsorti from Mont
Aimé, France, and in Pyenodus platessus from Monte Bolca, Italy
(Nos. 41083, P. 4386). They also occur in the type-specimen of
Xenopholis carinatus and in a new specimen of the latter species
(No. P. 10700). Similar teeth are seen in front of the mandible of
a specimen of Xenopholis in the Court Museum, Vienna; and five
1 E.C. Starks, ‘‘The Osteology and Relationships of the Family Zeide”’:
Proe. U.S. Nat. Mus., vol. xxi (1898), p. 471, pl. xxxiii.
2 W. Dames, ‘‘ Ueber Ancistrodon”’: Zeitschr. deutsch. geol. Ges., 1883,
pp. 655-70, pl. xix. See also figure by A. Gaudry, Les Hnchatnements du
Monde Animal.—Fossiles Secondaires (1890), p. 167, fig. 263.
388 Dr. A. Smith Woodward—Notes on Pycnodont Fishes.
of them, sufficiently large to have been the premaxillary and dentary
teeth, have been found with a group of tritoral teeth of Acrotemnus
in the Chalk of Belgium.! Larger and stouter examples of ‘‘ Anev-
strodus’’, therefore, are probably the prehensile teeth of Pycnodont
jaws;? but the smaller examples, with translucent or transparent
enamel, belong to the pharyngeal dentition.?
In Celodus the preoperculum is subdivided by an irregular
transverse suture into two portions, the lower being the larger. The
vertical slime-canal, which always traverses the preoperculum in
Pycnodonts near its anterior border, passes directly into the upper
portion, thus proving that it is not the operculum, as it has been
named by Kramberger,* and also by Bassani and D’Erasmo.? The
operculum in Celodus resembles that of other typical Pycnodonts,
and the same bone in Stemmatodus is figured by Bassani and
D’Erasmo® as a supraclavicle.
The ribs in Pycnodonts are comparatively short, extending not
more than half-way to the ventral border. Each bears a paired
laminar expansion tapering distally, as well seen in a specimen of
Gyrodus in the British Museum (No. P. 162382).
In the pectoral arch the supraclavicle has now been clearly
observed in Mierodon radiatus from the Purbeck Beds. Its exposed
upper portion, crossed by the slime-canal, is triangular in shape, and
its apex is situated at a short distance below the posterior process of
the parietal bone.
In the typical Iesodon (Figure on p. 386), as in most Pyenodonts,
the flank-scales are complete only in the lower part of the abdominal
region, beginning with four or five in the transverse row immediately
behind the pectoral arch and gradually diminishing to two or three in
the last row just in front of the anal fin; the uppermost scale in each
row tapering upwards to its riblet. In some of the earlier species
commonly referred to Mesodon, however, such as I. liassicus, the
scales are complete throughout nearly all the transverse rows; and
I unfortunately made the mistake of representing this type of
squamation in my first restoration of Jf. macropterus,’ which is now
corrected. In those genera in which the squamation is more or less
nearly complete, either over the whole or the front half of the trunk,
the scales are less deep and more numerous than in the genera in
which the squamation is much reduced.
In nearly all Pycnodonts the ventral ridge-scales occur in un-
interrupted series, and the small pelvic fin on each side is inserted
1 M. Leriche, ‘‘ Un Pyenodontoide aberrant du Sénonien du Hainaut” :
Bull. Soc. Belge Géol., vol. xxv oe: Proc.-Verb., pp. 162-8, pl. A.
2 e.o. specimen figured by A. S. Mopars Fossil Fishes of English
Chalk (Mon, Pal. Soc., 1909), pl. xxxv, fig. 8.
* e.g. specimen figured by A. 8S. Woodward, Proc. Geol. Assoc., vol. x
(1888), pl. i, fig. 10.
4D. G. Kramberger, Djela Jugoslav. Akad., vol. xvi (1895), pp. 21, 31,
HEN iq Wal
5 F. Bassani & G. D’Hrasmo, ‘‘ La Ittiofauna del Caleare Cretacico di
Capo d’Orlando [ESE Castellammare (Napoli) ” : Mem. Soe. Ital. Sci. [3],
vol, xvii (1912), p. 227, ig. W2.
6 Loc. cit., p. Dal. fic. 9.
GATS: Woodw ard, Vertebrate Paleontology (1898), p. 105, fig. 74.
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Herbert L. Hawkins—Studies on the Echanoidea. 389
just above them. In most cases the two transverse rows of scales
diverge at their lower end to admit the insertion of this fin and the
intercalation of one scale behind it. One ventral ridge-scale at this
point thus bears two facettes, one for its corresponding normal flank-
scale, one for the intercalated scale. In Pyenodus and the so-called
Paleobalistum ponsorti, one transverse row of scales seems to bifurcate
at its lower end to accommodate the pelvic fin, and there is a gap in
the ventral ridge-series immediately beneath it. The position of the
anus is uncertain.
It is interesting to add that both in Mesodon and Microdon one or
perhaps two small rhombic ganoid scales remain on the upper
caudal lobe.
As to the systematic arrangement of the Pyenodonts, it is clear that
the earliest species usually referred to Mesodon are the most primitive.
I have placed them in a distinct genus in the forthcoming part of my
Monograph of Wealden and Purbeck Fishes. Gyrodus and Mesturus
are closely related to each other and diverge in several respects from
other members of the group. The well-armoured Cretaceous forms,
Coccodus and Xenopholis, are also peculiar. The general trend of
specialization in the family seems to be as already stated in the
British Museum Catalogue of Fossil Fishes.
EXPLANATION OF PLATE XXIV.
Pycnodus platessus, Agassiz; photograph of nearly complete fish in lime-
stone, showing a mass of comminuted shells within the abdominal
region. Nat. size. Upper Eocene: Monte Bolca, near Verona, Italy.
British Museum, No. P. 1633.
IJ.—Morpruotocicat Stupies on THE EcurnorpEaA HoLecryPoIDA AND
THEIR ALLIES.
By Hersert L. Hawkins, M.Sc., F.G.S., Lecturer in Geology, University
College, Reading.
_Y. Tue Perienaruic Girpie oF Drscorpes cyLrnpricus (LaMARcK).
(PLATE XXYV.)
1. Iyrropucrion.
Pp M. DUNCAN, to whose work we owe the standardization of
. our knowledge concerning the ambulacral structures of the
Echinoidea, published in 1885! a memoir “‘ On the Perignathic Girdle
of the Echinoidea’’, in which he definitely established the principles
whereby this apparatus may be described and put to taxonomic use.
The actual term ‘‘perignathic girdle’’, first introduced in that
paper, was given with direct reference to the ‘‘ perfect girdle around
the jaws in Discoidea”’ (1.c., p. 207), although no detailed account
of the peristomial structures of that genus was included. In the
following year the same author, in collaboration with W. P. Sladen,
gave a full description of the girdle of Discoides, in the light of the
results reached in the previous work. The same two authors
practically repeated their opinions on this topic in a later paper
published in 1889.
! See list of literature at the end of this paper.
390 Herbert L. a ie SS emcee on the Echinoidea.
In 1884, in this Magazine, Duncan, to use his own words,
‘‘ enlarged upon the nature of the peristomial structure of Galerites
albogalerus”’ (Conulus), and proved, at least to his own satisfaction,
that neither jaws, teeth, nor perignathic girdle, were developed in
that species. ‘l'o this opinion he and Sladen adhered in 1889.
During the same period Lovén had turned his attention to the
perignathic structures of the MHolectypoida, and published the
results of his researches in 1888 in the course of his paper on
the (probably misleading) discovery of Pygastroides relictus. In
respect of the perignathic girdle of Dvuscoides, Lovén’s observations
led him to conclusions as to its structure which were diametrically
opposed to those of Duncan and Sladen in practically all features of
importance. He also expressed the belief that both Dvzscorides and
Conulus were furnished with lanterns and teeth. To this Duncan
and Sladen replied in 1889 by a regrettably dogmatic paper in which
they repeated their previously expressed views, after the examination
of anew series of specimens. Again they stated that the girdle of
Discoides was composed wholly of interambulacral structures (ridges) ;
that Conulus had no girdle at all, or at most a degenerate and
functionless ridge; that it was extremely improbable that Discoides
had any jaws; and, by inference, that it was practically certain that
Conulus was totally devoid of a lantern. In 1892 Lovén published
a fuller account of the girdles of the two genera, and, either in
charity or sarcasm, referred to the work of the two British authors
in a footnote only, without comment. He also had the intense
satisfaction of being able to describe the pyramids of the lantern in
Discoides.
Since the period of this somewhat strained, but eminently
courteous, controversy, the present writer has published a more
complete account of the lantern and teeth of Drscordes (1909), and
has recorded the discovery of indubitable teeth in Conulus subrotundus
(1911). For the rest, the question of the characters of the
perignathic girdle in the two genera remains practically in the
unsatisfactory condition in which it was left.
The difference between the two interpretations of the girdle of
Discoides can be best understood by a comparison of the figures given
by the respective authors. If, following the advice of Duncan, we
‘very respectfully draw our... attention to [ Lovén’s drawing ],
fig. 2”’ (here partly reproduced in outline on Pl. XXV, Fig. 2), we find
that each sector of the girdle is composed of four ver tically elongated
plates, the outer pair of which is united to the ambulacra by suture,
while the inner pair articulates with three small polygonal plates on
the interambulacral margin of the peristome. The outer pair consists
of ‘processes’? in Duncan’s terminology, while the inner pair, with
the three small plates, constitutes the ‘‘ ridge’. On comparing this
drawing with Duncan & Sladen’s very diagrammatic sketch (here
copied in part, Pl. XXV, Fig. 1), the only discrepancies to be noticed
are in the absence of the median interambulacral suture and of the
small plates, and in the straightness of the sutures at the bases of the
processes. (With the position of the ambulacral pores, another
point of difference, we are not now concerned.) But the interpretation
Herbert L. Hawkins—Studies on the Hchinoidea. 391
of their diagram given by the last-named authors affords a most
striking contrast with that which must inevitably apply to Lovén’s
drawing. They maintained that the straight suture which comes at
the adradial base of the projecting part of the girdle was the
‘‘interradio-ambulacral”’ (adradial) suture, and that the three large
constituents of the girdle were all wholly interradial in position.
T'wo such opposite interpretations of a superficially straight-
forward structure demand reconciliation. The chief purpose of this
paper is to show how this reconciliation can be effected. In the
next paper of this series a new reading of the girdle of Conulus will
be given (the denial of the presence of this structure is a lamentable
and inexplicable lapse on the part of Duncan & Sladen), together
with a general summary of the characters of the perignathic girdle
in the Order. I hope to publish a comparison of the girdles of the
Holectypoida and Clypeastroida at an early date, at the same time
discussing the homologies of the peristomial structures of the
Spatangoida.
2. Tue PerienatHic GirpLE or DrscompES CYLINDRICUS.
(a) Duncan & Sladen’s Interpretation. (Pl. XXYV, Fig. 1.)
The outstanding characters of the perignathic girdle as represented
by this diagram are: firstly, the presence of a low, thickened margin
to the peristome in the ambulacral regions, perforated by three pore-
pairs in each area; and secondly, the development of smooth,
sloping ridges on the interambulacral margins, each composed of
three flat plates, of which the central one is large and roughly
rectangular in shape, while the outer (adradial) two are narrow
adorally, expanding distally into prominent ‘‘ears”. There is
nothing inherently improbable in the ambulacral part of the girdle,
for it would prove to be in a slightly modified Cidaroid stage of
development. But the existence of three plates, representing three
columns, in the interambulacra, would be a most extraordinary
_ anomaly. Itistrue that in the somewhat obscure Zvarechinus and
Lysechinus from the St. Cassian Beds of the Trias, the interambulacra
are believed to show three columns (represented by one plate each)
above the primordial, but to find such a feature in Discordes, especially
when the rest of the interambulacra are built of the normal two
columns, would be indeed marvellous. Even if the large central
plate of the ridge be regarded as the primordial, and the two plates
at the sides as the first two paired plates of the area, the figure
becomes only less grotesque.
A comparison of the figure with a prepared specimen shows that
the former is, as regards its drawing, a fair, though diagrammatic,
representation of the appearance of the girdle. But the sutures near
the ambulacral pores are not so straight as Duncan & Sladen make
them, and the lateral ‘‘eared”’ plates of their ridge are certainly
based. upon the proximal ambulacral plates. There can be no
possible doubt that their ‘‘ interambulacro-radial’’ suture is
really the basal suture of the process. The two ‘“eared’’
lateral plates of the ridge are therefore certainly processes, as
Lovén maintained. The true ridge, stripped of its radial
>... a
ve
iis
Be
&
392 Herbert L. Hawkins—Studies on the Echinoidea.
marginals, would then be left as a flat, sloping plate of large
size. This is certainly its general appearance in a specimen, but
with careful lighting it may be found that the ridge plate is not
flat but has a marked central concavity and several small irregularities
on the exposed face. Its free (distal) margin is never, so far as
I have determined, so straight as in the figure, and there is always
a decided change in the direction of that margin when the processes
are reached. But unless this large ridge represents simply the
primordial interambulacral plate (which is almost inconceivable) it
must necessarily be compound, and be crossed by sutures vertically
or transversely or both. Duncan & Sladen expressed surprise at
the apparent absence of sutures, but seem to have been satisfied that
they were not present in the specimen from which their diagram was
drawn. Their remarks (l.c., p. 237) imply that they were prepared
to believe that sutures might exist in the ridge in some specimens
and not in others. Such variability would be contrary to all
experience in Echinoid structure, and one can only believe that their
specimen was unsuitably preserved or cleaned for the display of the
sutures.
To sum up: the lateral lappets of the ridge in Duncan & Sladen’s
diagram are in reality processes, and there is every reason to believe
that the lack of suturesin the broad median plate is due to incomplete
observation.
(b) Lovén’s Interpretation. (Pl. XXV, Fig. 2.)
The beautiful figure published by Lovén in 1888 was copied by
him in 1892, with the addition of another in which no sutures were
shown. The twice published figure (here copied) was taken from
the girdle of a depressed form of WD. cylindricus, while the other
represented a modification of the processes which Lovén thought to
be restricted to the elevated, cylindrical form. lLovén suggested
that the striking diversities between the superficial aspects of the
two girdles might imply a specific difference between the two forms.
In 1909 I showed that the ‘‘ forma elatior”’ type of girdle could be
found in specimens of the ‘‘ forma vulgaris” (or ‘‘ depressa.”), and
subsequent observations have confirmed this. The difference between
the two types consists in the greater prominence of the processes in
the ‘‘ forma elatvor’’ and in their inappreciable elevation beyond the
apex of the ridge in the depressed form. This would appear to be
a modification due solely to the size (i.e. age) of the specimen. The
occurrence of the two kinds of girdle in the same form in no way
vitiates the possibility of there being two distinct varieties of the
species ; on the contrary, it makes it the more probable that the two
forms are definitely distinct. While the largest specimens of
D. cylindrieus that I have seen are all of the ‘‘ forma elatior ”’, I have
examined numerous specimens of the ‘‘ forma vulgaris”? which were
much larger than many decidedly cylindrical examples.
To turn to an analysis of the figure here copied: The outline of
the girdle is for all practical purposes similar to that shown in
Duncan & Sladen’s figure. But the sutures at the bases of the
processes are represented as curved, somewhat irregular lines, while
Herbert L. Hawkins—Studies on the Echinoidea. 3898
the ‘‘lappets’’ of the processes, and indeed the whole ossicles, are
shown to overlap the poriferous zones of the ambulacra. The central
portion, or true ridge, of each section of the girdle is divided into
two main sections by a more or less median suture, and at the margin
of the peristome there are three small, unequal and irregularly
shaped plates. In two of the areas, Nos. 4 and 5, Lovén, with his
customary faithfulness to observation, has indicated some of the
sutures in the ridges by broken lines, thus proving that in the other
areas he could clearly distinguish the outlines of the plates. (No
sutures whatever, either in the girdle or on the adoral surface of the
test, are drawn in his figure of the ‘‘ forma elatior”, which was
evidently a fully grown specimen in which secondary thickening
had covered the original surfaces of the plates.) In one of the
many preparations of the girdle of Discozdes that I have made, there
is a distinct median suture in some of the ridges, and fairly con-
vineing evidence of the existence of a small triangular plate in the
middle line at the peristomial border. By means of thin sections
examined under crossed nicols, I have been able to confirm the
presence of this small plate. I have not succeeded in tracing the two
small plates which Lovén figures on each side of the median one;
but the fidelity of his observations is so uniform that there can be
no reasonable doubt of their occurrence, in some examples, at Jeast.
Lovén’s drawing differs from that of Duncan & Sladen in these
two fundamental points only: it is a faithful copy, not a diagram,
and it contains a record of more complete observation. In its
essential features I can confirm its accuracy from original observa-
tion. Itis perhaps worth remarking that I made sketches which
agree with Lovén’s figure (with the exception noted above) before
I had adequately studied his drawing. In the detection of sutures,
particularly where they are faint and of unusual distribution, it is
distressingly easy to be influenced by preconceived ideas. On
re-examining my specimens after becoming familiar with Lovén’s
- rendering, not only do the sutures previously detected seem far more
obvious than before, but it is quite possible to imagine the presence
of the two small plates on either side of the median one at the
peristomial margin. However, experience has made me so wary in
these matters that I have failed to convince myself of the certain
occurrence of the sutures which would be the boundaries of such
plates. That they were patent in Lovén’s specimen I fully believe.
(c) A suggested new interpretation. (Pl. XXV, Figs. 3 and 6.)
In spite of the doubts entertained by Duncan & Sladen, there is
no difficulty in recognizing the processes in the girdle of Discocdes.
Separated from the ridges, they present a marked similarity to
those of Plesvechinus (see part iv of this series). It is in the ridges,
which were hardly developed in the Jurassic Holectypoida, that
the peculiarity occurs. The primordial interambulacral plate is
generously represented at the peristomial margin in all five areas in
Discordes (see Lovén, 1872, pl. xiv, fig. 125). In the majority of
those Diademoida which have a strongly developed ridge, this
1 Ba ove
of
|
394 Herbert L. Hawkins—Studies on the Hchinoidea. |
structure is composed of a varying number of paired interambulacrals
at its base, and has an apparently undivided plate along its free
margin (see Duncan, 1885). It is possible that this unpaired
plate may represent the primordial interambulacral (which is absent
from the peristomial margin in these forms); or perhaps an out-
growth from it prior to its resorption. But in Discoides, where the
primordial plate is situated on the peristomial margin, the distal
part of the ridge is definitely composed of paired plates.
In Plesiechinus the only representative of the ridge is found as
a semilunar inward prominence of the primordial interambulacral.
It is, as far as my observations indicate, and as would be expected
from its position, absolutely undivided by sutures of any kind. In
Discordes the small median peristomial plate of the ridge is slightly,
but definitely, more prominent than the rest of the structure. It is,
almost certainly, the inner surface of the primordial plate. This
small portion of the ridge must therefore be the homologue of the
“ridge”? of Plesiechinus.
In the Cidaroida and Diademoida the ridge is only connected to
the normal coronal plates at its base, projecting almost vertically
from their horizontal inner surfaces. In Discoides, on the contrary,
the whole ridge, with the exception of an almost negligible rim at
its distal extremity, is recumbent upon the interambulacrum, which
is thickened so as to project in some cases (in internal aspect) to
a greater height than the ridge itself attains. (See Pl. XXYV, Fig. 3.)
The degree to which the ridge extends above its supporting plates
varies considerably, apparently with age. In some forms, where
the radiating buttresses are low and feeble, the projection of the
ridge may amount to nearly half its total height. It will be noticed
in Lovén’s figure (my Pl. XXV, Fig. 2) that the median suture of
the ridge is directly continuous with that of the normal part of the
interambulacrum. These distal plates of the ridge of Dvscordes,
which constitute the greater part of the ridge, surely represent the
inner surfaces of the paired interambulacrals next to the primordial,
modified as supports, perhaps as actual “slides’’, for the inclined
lantern. The projecting rim of the ‘‘ ridge”’ need cause no surprise
when the extraordinary pillar-like and carinate internal develop-
ments of the inner surface of the Clypeastroida, and indeed of
Discordes itself, are taken into account.
If this interpretation of the girdle is correct, it follows that the
girdle proper consists of the paired processes and small triangular
peristomial plate of the interambulacrum ; and that the bulk of the
ridge is merely a specialized portion of the thickened paired plates.
There is then no difficulty in considering the two small lateral plates
of Lovén’s figure, which form the interradial sides of the branchial
incisions, as the first paired columnals; while the two large upper
plates represent the somewhat expanded and modified inner surfaces
of the second pair. All of the ‘‘ridge”’ except that part built of the
small proximal median plate, is then not homologous with the ridge
of a Diademoid. I would call it a ‘‘ false ridge”. It serves, like
the buttresses recently described in Plestechinus, as a mechanical
support for the processes; and has the additional function of
Herbert L. Hawkins—Studies on the Echinoidea. 395
providing a smooth, slippery surface on which the splayed pyramids
of the lantern could recline.
(d) The position of the gaw-muscles. (Pl. XXV, Fig. 6.)
There is a clearly defined articular facet on the upper part of each
process which undoubtedly served for the attachment of the retractor
muscles. I have failed to find any other indications of muscle-
attachments upon the processes; and, to judge from the known
characters of the pyramids, it seems improbable that a second pair of
retractors was present.
The position of attachment of the protractor muscles is less clear.
In those Clypeastroida which have paired processes, the protractors
arise from the interradial sides of the processes, usually at or near
their bases. Such a position for the protractors is quite impossible
in Discoides, since there are no ‘“‘interradiad faces” to the processes
owing to the great height of the ‘‘false ridges’”’. Hence the
protractors must have been attached to some part of the ridge or
‘‘false ridge”’; that is, in the Diademoid manner. I have not been
able to recognize any muscle-impressions on the interradial parts of
the girdle. Clearly the broad, shallow, elliptical depression which
occupies most of the surface of the false ridge is not a muscle-scar.
In some specimens there are very small and inéonspicuous knobs on
the false ridge at the upper corners of this central depression. They
do not, however, suggest muscle-attachments, since these are
normally roughened and depressed in Kchinoid girdles. There
remains the somewhat prominent ‘“‘true ridge”, on the actual
margin of the peristome. If the interpretation of the girdle given
above is correct, this is the proper situation for protractor attach-
ments, by analogy with the Diademoida. It will be seen that in
Pl. XXV, Fig. 6, I have based these muscles upon this median
thickened plate. A further reason for this reconstruction—one that
seems to me to be very cogent—is the normal direction of the
protractor muscles. These, in the Diademoida, pass almost vertically
‘from the low ridges to the tops of the hemi-pyramids. Owing to
the prominence of the true ridge in Discovdes, such a muscle arising
from it would have free play for a considerable distance in all
directions (see Pl. XXV, Fig. 6). Owing to the concave curvature of
the rest of the ‘‘ridge”’, the only other position from which similar
freedom could be attained would be the actual crest—a most unlikely
place for the attachment of a strong muscle.
There is no evidence for the existence of radial compass muscles,
nor of compasses in the lantern. Although negative evidence, when
concerned with structures of such delicacy, is utterly unreliable,
I have omitted them from the restored figure in view of their
proved absence in the Clypeastroida. If it should be shown that
Discoides had compasses, I should incline to find the attachment
of their muscles on the true ridges between the pairs of protractors.
_ (e) The nature of the ‘‘ false ridges’’.
If the foregoing argument respecting the position of the muscle-
attachments of the perignathic girdle of Descoides is accepted, the
interradial portion that I have called the false ridge is seen to be
396 Herbert L. Hawkins—Studies on the Echinoidea.
divorced from the true girdle as regards function. That it serves as
a useful support for the very slender processes is obvious; and that
it consists of the bevelled and otherwise modified edges of the very
thick proximal coronal plates seems equally clear. In the previous
article in this series (Grot. Mac., August, 1917), I showed that the
processes of Plesiechinus are supported by thick buttresses which are
built almost wholly of thickened interambulacral plates. The
buttresses of the Jurassic genus are so similar in character, though
far different in extent, to the carinate thickenings of the adoral
surface of Discordes, that it is practically certain that the latter
structures represent a phylogenetically later stage of the former.
The buttresses of Plestechinus pass towards the median interradial
lines after leaving the processes, and subsequently return to the neigh-
bourhood of the adradial sutures. In Discordes (see Pl. XXV, Fig. 3)
they may be said to have a similar course, but each pair converges
interradially to such a degree that fusion results. Thus the whole
proximal part of each interambulacrum becomes much thickened,
although elsewhere on the adoral surface the test is extremely thin.
The false ridge therefore represents the bevelled edge of the fused
buttresses.
Nevertheless, the false ridge is a more specialized structure than
the preceding conclusion would demand. It is of closer texture
than the ordinary parts of the buttresses, projects to a varying
distance above them, and is hollowed in the centre. Clearly it
must have served some special function, for which these characters
are adaptations.
The strongly inclined (almost horizontal) pyramids of the lantern
of Clypeaster actually articulate with the processes. There are no
buttresses or analogous supports in the immediate vicinity of the
peristome in this type. The lantern of Dvzscordes, as Lovén and
I have described it, was evidently ‘‘ flaring”? in character, though
far more nearly vertical than is the case in Clypeaster. Since
pyramids are interradial in position, it follows that they would lean
over the proximal interradial plates, if splayed outwards. In
Discoides these plates are much thickened; hence they must be
bevelled off so as to afford play for the pyramids. It is at least
likely, by comparison with the closely related Clypeastroida, that
the pyramids may have actually leaned against the bevelled edges
(false ridges) when the jaws were closed. This would bea preliminary
to the actual articulation found in the last-named group. It may
therefore be suggested that the smooth, concave surfaces of the false
ridges served as ‘‘slides” for the pyramids, allowing them to be
drawn up or down according as the teeth were withdrawn or
extruded; and preventing the strain which would inevitably fall
upon the muscles holding an inclined lantern together. The
hollowing of the adoral faces of the false ridges would, as shown
above, allow freedom of action for the protractor muscles.
38. SUMMARY.
The conclusions of Lovén as to the composition of the perignathic
girdle of D. cylindricus are confirmed in essential particulars, while
Grou. Maa., 1917. Pirate XXY.
Jel, 1b, Jeng (lel Bule & Sons, tmp.
PERIGNATHIC GIRDLE OF DISCOIDES CYLINDRICUS (Lam.).
Herbert L. Hawkins—Studies on the Hchinoidea. 397
those of Duncan & Sladen are shown to be based upon imperfectly
preserved material. The processes, which may project freely for
a varying distance above the rest of the girdle, are slender. The
actual ridges are represented, as in Plesiechinus, by the slightly
thickened and projecting inner surfaces of the unpaired primordial
interambulacral plates. The rest of the interradial portion of the
girdle is interpreted as being made of the bevelled edges of the
buttresses which radiate over the interambulacra of the adoral
surface. These sloping surfaces, here called ‘‘false ridges’’, are
believed to be specialized and somewhat extended as ‘‘ rests” or
‘¢slides”’ for the inclined pyramids; thus forecasting the articulation
between lantern and girdle found in the Clypeastroida. The
retractor muscles were attached to the upper parts of the processes,
and it is argued that the protractors must have sprung from the
small true ridges, the false ridges having no function as muscle
supports. In the absence of positive evidence, radial compass
muscles are presumed to have been absent.
4. Lisr or PapERS CONSULTED.
Duncan (P. M.). 1884. ‘On Galerites albogalerus, Lamarck, syn. Hchino-
conus conicus, Breynius”: Grou. Mac., Dec. III, Vol. I, pp. 10-18.
1885. ‘‘On the Perignathic Girdle of the Echinoidea”: Journ. Linn.
Soe. Zool., vol. xix, pp. 179-212, pls. xxx, xxxi.
—— & Suapen (W. P.). 1886. ‘‘On the Anatomy of the Perignathic
Girdle of Discoidea cylindrica”: Journ. Linn. Soc. Zool., vol. xx,
pp. 48-61.
1889. ‘‘ A note upon the Anatomy of the Perignathic Girdle of
Discoidea cylindrica, Lamk., sp., and of a species of Hchinoconus” :
Ann. Mag. Nat. Hist., ser. v1, vol. iv, pp. 234-9.
Hawkins (H. L.). 1909. ‘‘On the Jaw-apparatus of Discoidea cylindrica
(Lamarek)”: Grou. Magc., Dec. V, Vol. VI, pp. 148-52, Pl. VI.
— 1911. ‘‘On the Teeth and Buccal Structures in the genus Conulus,
Leske”: Grou. Mac., Dec. V, Vol. VIII, pp. 70-4, Pl. III.
Loven (S.). 1872. ‘* Etudes sur les Echinoidées””’ : K. Svensk. Vet.-Akad.
Handl., Bd. xi, No. 7.
—— 1888. ‘‘Ona Recent Form of the Echinoconide”: Bih. K. Svensk.
; Vet.-Akad. Handl., Bd. xiii, Afd. iv, No. 10.
—— 1892. ‘‘Echinologica”: Bih. K. Svensk. Vet.-Akad. Handl.,
Bd. xviii, Afd. iv, No. 1.
EXPLANATION OF PLATE XXY.
Fie.
1. Copy of the figure of the perignathic girdle of D. cylindricus given by
Dunean & Sladen (1889). The inner part of the figure, slightly reduced.
2. Copy of the figure of the perignathic girdle of D. cylindricus given by
Loven (1892). The inner part of the figure, slightly reduced ;
outline only.
3. The perignathic girdle of D. cylindricus (original). The figure is
diagrammatic in that the sutures in the ridges were only seen in three
of the areas, and the sutures of the coronal plates are omitted. The
ridges project very little above the fused buttresses. The processes
are intermediate in character between those of the ‘‘ forma vulgaris”
and ‘‘ forma elatior” of Lovén. The specimen is depressed hemi-
spherical in shape. The small true ridge is not quite so prominent as
represented.
4. Section through the interradial line of the girdle of a specimen in which
the ridge is unusually prominent, owing to the feeble development of
the buttresses.
398 H. A. Baker—Charnian Movement in East Kent.
Fic,
5. Corresponding section of a specimen like that shown in Fig. 3; the ridge
hardly projecting above the buttresses.
6. Diagram of the probable disposition of the jaw-muscles: re. retractors,
pro. protractors. The radial compass muscles are omitted, being
probably absent. The concavity of the false ridge is indicated by
a dotted line. The girdle is shown from the oral view, so that the
height of the processes and ridges is made to seem less than the actual
by perspective due to their inclined character.
I1I.—Evipence succEstive oF Cuarnian Movement 1n Kasr Kenr.
By Hersert ARTHUR Baker, B.Sc., F.G.S.
(WITH TWO MAPS: PLATES XXVI AND XXVII.)
COMPARATIVE study of the whole of the evidence concerning
the Paleeozoic floor beneath the South-East of England and the
manner in which the various members of the Mesozoics are disposed
upon it has led the present writer to conclude that the area,
originally defined by Professor P. F. Kendall,! over which the effects
of the operation of a ‘‘ posthumous”’ Charnian axis may be discerned,
can be greatly extended, more particularly to the eastward. The
evidence, indeed, strongly suggests the presence of a second Charnian
axis beneath Suffolk, proceeding thence south-eastward to North
France.
East Kent lies on the western flank of this alleged Charnian ridge,
and in view of the greater abundance of deep borings there, furnishes
the best area in which to study its influence upon both the Paleozoic
and Mesozoic rocks. With regard to the former, all the steadily
accumulating information concerning the structure of the South-
Kastern coalfield points to the presence, eastward of Kent, of a ridge
or barrier of a Charnoid or Malvernoid trend, which appears to have
been a potent factor during the deposition of the Kentish Carboni-
ferous, and which probably now separates the coalfield from that of
the Pas-de-Calais. In Kent the Lower Coal-measures, in the strict
sense, are absent, and have apparently never been deposited, and
there is no sign of Millstone Grit. The Middle Coal-measures lie
unconformably upon the Carboniferous Limestone. The latter has
been reached in several borings, particularly in North Kent, since
the general dip of the Carboniferous in Kent is to the south-west.
There is an area, a little to the north of Ebbsfleet, where, beneath
the ‘‘blanket’’ of Mesozoic strata, the Carboniferous Limestone
emerges from beneath the Coal-measures. For some five or six miles
to the south-west of this zone of Carboniferous Limestone, the
surface of the Paleozoic floor in East Kent is occupied by
a succeeding ‘‘ outcrop” of Middle Coal-measures, and these in their
turn are succeeded by the Transition Coal-measures which cover the
remainder of the surface of the known coal-basin to the south and
west, to and beyond Dover. The general strike of the strata in the ©
field is about 80° S. of E. and N. of W. A tendency of both Middle
1 Kendall, ‘‘Sub-Report on the Concealed Portion of the Coalfield of
Yorkshire, Derbyshire, and Nottinghamshire”: Final Report Royal Comm.
Coal Supp., pt. ix, 1905.
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H. A. Baker—Charnian Movement in East Kent. 399
and Transition Measures (but particularly the latter) to thin in an
easterly direction has been observed.’
The present contours of the Paleozoic floor in East Kent must
differ considerably from those presented by it during the time of the
encroachment upon it of the Lias and Oolites. Thisis in consequence
of the severe post-Jurassic earth-movements which have affected the
South-East of England. The most important of these movements
oceurred in post-Cretaceous times, and that which had the greatest
effect upon the Paleozoic floor was the one which resulted in
the uplift of the Weald. Its chief effect upon the old floor in East
Kent was to decrease very considerably the south-westerly slope.
Considering, for example, the average downward slope of the
Paleozoic floor from Ripple to Ellinge, it is now seen to be about
512% feet to the mile, whereas in pre-Cretaceous times 1t must have
been more than 110 feet to the mile. Consequently, in considering
the disposition and variation in thickness of the members of the
Mesozoic cover in relation to the old floor upon which they
successively encroached, it is necessary to have some idea of the form
of the latter as it was during the time of the deposition of these
Mesozoics. Map 1 (Plate X XVI) is inserted here in which an attempt
is made to eliminate the effects of post- Lower Cretaceous movements
from the Paleozoic floor by considering the base of the Gault as
a datum-plane and drawing a system of lines through points on the
floor at equal depths below it.2, This method naturally suffers from
the imperfections of artificiality, and, of course, gives only an
approximation to the true pre-Upper Cretaceous contours of the
floor, since no allowance has been made (nor, in the circumstances,
can be made) for the variation in depth of the Gault sea; but,
speaking generally, the chief error involved is that the south-
westerly slope of the floor appears somewhat less than it must
actually have been. The point, however, is one of no importance for
our present purpose.
The map shows very clearly indeed that in pre-Cretaceous times
the Paleozoic floor of Kast Kent was part of the western flank of an
elevated ridge lying to the north-east of the Ebbsfleet-Deal area, and
possessing a distinctly N.W.-S.E. trend. Westward, however, the
influence of the ridge is seen to die out. The contours present one
or two features of special interest. The lines do not everywhere
accord with those of a peneplain, but suggest, rather, immature
denudation, or, at any rate, interruption and readjustment of the
conditions under which denudation was progressing, by a movement
of uplift in the north, probably accompanied by faulting, along a new
and discordant line, viz. roughly east and west. An interesting
subsidiary ridge or spur (or disturbance) crossed the area, entering
Kent in the neighbourhood of Deal and dying out near Ropersole.
Turning now to the consideration of the features presented by the
Jurassic strata in proximity with this N.W.-S.E. ridge, we find
abundant evidence not only of the existence of the ridge in Jurassic
Be evel Arber, Trans. Inst. Min. Eng., vol. xlvii, pt. v, pp. 677-724,
14.
2 See Table I, p. 402, at end of paper.
\
400 H.A. Baker—Charnian Movement in East Kent.
times but also of the occurrence along it of repeated movements of
uplift, in fact ‘‘ posthumous’? movements. It is significant, too, that
the series of disturbances which can be traced is in remarkable
agreement with the movements cited by Professor P. F. Kendall! as
having occurred along the line of his celebrated Charnian axis. In
the East Kent Jurassics illustrations may be noted of practically
every kind of evidence that superincumbent strata can yield con-
cerning the proximity of an axis of instability. The detailed account
of the Jurassic succession in the deep borings at Brabourne and
Dover, given in a Survey memoir,” is most interesting from this
point of view. At Brabourne, although Lower, Middle, and Upper
Lias are represented, the total thickness is but 140 feet, and at
Dover, although all three divisions apparently still occur, the total
thickness of the formation has dwindled to less than 40 feet. At ~
several horizons planes of erosion occur, and rolled fragments,
nodules, and broken fossils are abundant.
It is to be regretted that similar detailed accounts of the Lias
proved in some five or six other deep borings in East Kent are not as
yet available. At present we have little more than the recorded
thicknesses to work upon (and even these sometimes differ where
more than one record exists), and. so many different circumstances
combine in affecting the thickness of a deposit that, in general, it
would be scarcely safe to base any definite conclusions on it alone.
Nevertheless, in the present case, the tracing of isopachyte systems
in the Jurassic strata of Hast Kent (Map 2, Plate X XVII) results in
a series of lines revealing the closest sympathy with the pre-Upper
Cretaceous contours of the Paleozoic floor and bringing out clearly the
north-easterly encroachment of the Mesozoics upon the subsiding ridge.
In the case of the Lias the evidence® is sufficient for the insertion
of three isopachytes, viz. 0 (feather-edge of formation), 50 feet, and
100 feet. We see that with proximity to the easterly ridge the
isopachytes reveal a marked tendency to take on a N.W.-S.E. trend.
The influence of the Deal—-Ropersole elevation upon the 0 isopachyte
of the Lias is interesting.
Passing to the Oolites we have more data to work upon and the
results are still more interesting. What detailed information we
possess concerning the Oolite succession in the borings, adds to the
evidence in favour of posthumous movement along the easterly ridge.
At Dover, as in Kendall’s area, there is a marked non-sequence
between the Oolites and the Lias. The Inferior Oolite, which
undergoes a remarkable attenuation in Northamptonshire, and
becomes more and more sandy as the Charnian axis is approached, is
doubtfully represented at Dover by less than 30 feet of calcareous
sandy grit. and clay, and at Brabourne by about 40 feet of muddy,
1 Kendall, loc. cit.
2 Lamplugh & Kitchin, On the Mesozoic Rocks in some of the Coal
Explorations in Kent (Mem. Geol. Surv.), 1911. N.B.—It is not proposed
to deal fully with this evidence here. The reader is referred to the memoir
quoted, pp. 5-56, for abundant details, and to p. 94 for the significant
conclusions arrived at by the authors.
5 See Table of Thicknesses (Table II), p. 403, at end of paper.
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H. A. Baker—Charmian Movement in East Kent. 401
oolitic limestone with a pebbly base. Withregard to the Bathonian,
the record of the Hast Kent borings emphasizes Kendall’s remark
that ‘‘the unconformable overlap of the Great Oolite is one of the
most marked features of Qolitic succession in Britain and in the
north of France’’. The overlap of the Bathonian on the Paleozoic
floor in East Kent occurs as a zone of N.W.-S.E. trend extending to
northward of Stodmarsh and Woodnesborough. In tracing the
isopachyte system of the East Kent Oolites the thicknesses! have
been taken from the base of the Inferior Oolite to the top of the
Portlandian, excluding the Purbeckian, since in the boring records
the latter is sometimes not separated from the Wealden. Since it is
only in the southern part of the area that Oolites higher than
Corallian occur, there is no danger of arriving at erroneous con-
clusions in consequence of the omission of the Purbecks.? The Oolite
isopachyte system proves very interesting (Map 2, Plate X XVII). We
notice again the marked north-easterly thinning of the formation,
with a strong tendency on the part of the isopachytes to assume
a N.W.-S.E. alignment within the zone of influence of the easterly
ridge. We also perceive once more an intimate relationship between
the isopachytes and the pre-Upper Cretaceous contours of the
Paleozoic floor. The effect of the Deal—Ropersole disturbance upon
the isopachytes is very clear. There is, however, a particularly
interesting and instructive feature presented by these isopachytes
which appears to be missing from those of the Lias. In referring to
the general character of the pre-Upper Cretaceous contours of the
Paleozoic floor, mention has been made of the abrupt interruption,
in the north, of the general north-westerly trend of the contours, and
the suggestion has been put forward that this may be due to
a movement (late Jurassic or early Cretaceous) of uplift in a new and
discordant direction—in fact, roughly east and west. It will be
noticed that in the north and west the Oolite isopachytes show
a marked tendency to deviate southwards and to approximate to an
E.-W. rather than a N.W.-S.E. direction. In the opinion of the
‘present writer this southerly deviation of the Oolite isopachytes may
be, in part, the result of denudation consequent upon the appearance
of an east and west ridge of Oolitic rocks. It has long been known
that such a ridge, extending westward beyond Streatham, existed in
late Jurassic or early Cretaceous times, and was subjected to extensive
denudation in Lower Greensand times and probably earlier. The
writer regards this axis of uplift as one of Armorican affinity. The
Oolitic ridge was partially submerged in Lower Greensand times and
completely so during Gault times. The deep borings at Bobbing and
- Richmond showed the Lower Greensand resting on Oolites, while at
Stodmarsh, Streatham, and Meux’s Brewery the Oolites are directly
succeeded by the Gault.
To the north-east of the feather-edge of the Oolites, there is an
area, proved by the borings at Walmestone, Mattice Hill, and Ebbs-
fleet, where the Wealden overlap on the Paleozoic floor occurs. To
1 See Table II, p. 403, at end of paper.
2 In point of fact, the inclusion of the Purbecks still further emphasizes
the north-easterly thinning of the Oolites.
DECADE VI.—VOL. IV.—NO. IX. 26
402 H. A. Baker—Charnian Movement in East Kent.
the south-east of this area there is, in all probability, another where
a Lower Greensand overlap occurs, since at Mattice Hillthe Wealden
is but 2 feet thick. In relation to the alleged easterly Charnian
ridge, this area on the Kentish coast immediately to the south-east
of the Mattice Hill boring is in parallelism with the boring at
Culford in Essex, where the Lower Greensand overlap has been
demonstrated. Doubtless, further south-east, beneath the waters of
the Straits, there occurs an overlap of the Gault upon the Palewozoic
floor in parallelism with the proved overlap at Harwich, Stutton,
and Weeley.' On the south-easterly extension of the ridge, in North
France, there occurs an area where an overlap of the Middle Chalk
upon the Paleozoic floor exists. Apparently the ridge attained its
greatest elevation to the south-east.
With regard to the isopachyte systems of the Cretaceous members
of the Mesozoic cover, it is only to be expected that the intervention
of a wedge-like mass of older Mesozoics,and the interference introduced
by the Armorican movement, would mask to a large extent the
relationship so readily traceable between the isopachytes of these
older strata and the contours of the Paleozoic ridge. Nevertheless,
in spite of these disturbing elements, it is still possible to perceive
the influence of the ancient ridge.
In the opinion of the writer the South-East of England furnishes
much evidence suggestive of Charnian posthumous movement, and
that afforded by East Kent is a significant contribution.
TABLE I.
Paleozoic Floor when
Bornes Base of Gault referred Paleozoic Floor base of Gault is cor-
to O.D. referred to O.D. rected to a datum-
plane at O.D.
; Feet. Feet. Feet.
Chilham . — 544 —1,022 — 478
Brabourne +149 —1,706 — 1,855
Stodmarsh —931 — 9179 — 48
Trapham — 841 — 1,065 — 224
Goodnestone — 825 — 1,052 er |
Woodnesborough —917 —1,021 — 104
Fredvyille .. —689 —1,109 — 420
Barfreston — 691 — 15027 — 336
Tilmanstone V7 — 943 — 232
Maydensole — 641? (2) — 941 — 300? (?)
Ripple — 722 — 814 Se
Oxney — 696 — 859 = 168
Ropersole — 553 —1,174 = (il
Waldershare — 651 —1,069 — 418
Ellinge — 273 colle oulal — 938
Dover —192 —1,108 — 916
Ebbsfleet . —995 *—1,046 =. 151
Mattice Hill — 909 — 964. see
Walmestone —978 —1,001 — 23
1 The Gault overlap has been proved in a deep boring at Calais.
2 Estimated.
mg
Arthur Holmes—The Granophyres of Carrock Fell. 403
TABLE JI.
(Ryickvede omiinctie Thickness of Oolites,
Boring. present, exolud ie
Feet.
Chilham 23% feet 4122
Brabourne . THI) 5 1,020
Stodmarsh. Patsy a Wan 43
Trapham Absent 126
Goodnestone Absent 142
Woodnesborough Absent 30
Fredville P 104 feet 323
Barfreston . Absent 257
Tilmanstone Absent 133
Maydensole Absent 152
Ripple Absent ? (less than 92)
Oxney Absent 93
Ropersole . 21% feet 463
Waldershare Sak 301
Ellinge 54, —C«g, 695
Dover Bie) gs 504
Ebbsfleet Absent Absent
Mattice Hill Absent Absent
Walmestone X Absent Absent
LV.—A.siTE-GRANOPHYRE AND Quartz-Porpuyry FRoM Branpy GILL,
Carrock FE Lt. -
By ArtHur Hormus, A.R.C.S., D.Sc., F.G.S.
With an analysis by H. F. Harwoop, M.Sc., Ph.D.
InTRopUCTION.
fe the course of an investigation into British resources of sands
and rocks for glass-making and refractory purposes, which is
being carried out by my colleague Dr. P. G. H. Boswell, it became
’ desirable to search for an alumina-bearing siliceous rock low in
iron-content. Among other rocks considered by Dr. Boswell was
the granophyre of Brandy Gill, and a sample, obtained from Mr. W.
Hemingway, was submitted to Dr. H. F. Harwood for analysis. So
far as industry is concerned, the analysis indicates that the iron-
percentage of the rock is too high for its use in glass manufacture.
As such an analysis would be of interest and value to geologists—
there being few first-class analyses of Lake District igneous rocks—
and as it seemed undesirable that only a bare record should occur in
a technological publication, Dr. Boswell handed to me the analysis
and a sample of the granophyre, with the suggestion that the rock
might be described in the pages of the Grotocican Magazine.
I am indebted to Mr. Hemingway for two additional specimens
of the rock, which occurs near the head of Brandy Gill, west of
Carrock Fell. hese specimens, though from practically the same
locality as the granophyre, differ from it in having somewhat larger
phenocrysts of quartz and albite and a more finely grained ground-
mass very nearly free from micrographic texture. ‘They are
404 Arthur Holmes—The Granophyres of Carrock Fell.
therefore more accurately described as albite quartz-porphyry.
Mr. Hemingway states that the rock was first noted in some mine
workings near the head of Brandy Gill, where it was covered at the
surface by a white decomposition product. he latter, which is
known as ‘‘the china-clay bed’’ has been traced for more than
a mile in a westerly direction. At Arye-stones the deposit is very
extensive, but the fresh rock below was cut through by the old
levels of the Roughten Gill lead-mines. At Brandy Gill the rock is
penetrated by the tungsten veins of the Carrock mines, which carry
scheelite and wulfenite.!
PrETROGRAPHY OF THE ALBITE GRANOPHYRE.
The granophyre of the Carrock Fell complex and its variations
are well known from the description by Dr. Harker.? He describes
the normal granophyre as showing® ‘‘small scattered crystals of
black augite [diopside approaching hedenbergite] and white or
glassy-looking oligoclase, in a fine-textured grey or cream-coloured
or reddish groundmass’’. He then continues, ‘‘In some of the more
acid examples the augite is wholly or almost wholly absent, and the
rock has a white colour. ‘This is the case at the head of Brandy
Gill and in the peat moss south of Drygill Head, and the specific
gravity of these specimens is naturally very low (2°578 and 2°530).”
The specimen analysed by Dr. Harwood is a white quartzite-like
rock with sparsely distributed rectangular crystals of felspar which
average about 3mm. by 1 mm. in areal dimensions. The specific
gravity is 2°63.
Under the microscope the felspar phenocrysts are seen to be dusky
from incipient alteration, and to carry as inclusions small films and
fans of muscovite. Albite, pericline, and carlsbad types of twinning
are developed. A few cleavage flakes were obtained by crushing
the rock, and the extinction angles (up to 19° on 010), mean refractive
index (between 1°53, chlorobenzene, and 1-54, clove oil), and specific
gravity (2°63 in a Klein solution of that density) indicate that the
felspar is albite, a conclusion which is verified by the analysis.
The rock is crowded with small irregular crystals of quartz,
often corroded, and varying regularly in size from undoubted
phenocrysts to small masses that form part of the micrographic
groundmass. The latter is of the finely textured type described by
Harker,‘ with occasional felspar nuclei in optical continuity with that
of the surrounding intergrowth. There are, however, numerous
minute wisps of muscovite in the groundmass, and much of the
felspar of the latter is altered to cloudy aggregates of sericite.
Moreover, the rock contains here and there small fans of radiating
muscovite with which zircon in well-crystallized prisms or rounded
grains is invariably associated. No definite pyroxene has been
1 For an account of similar veins in the Grainsgill greisen see A. M.
Finlayson, Grou. Mac., Dec. V, Vol. VII, p. 19, 1910.
2 4.) 2000
Wie O) 5 34 "Melee -0157
CaO . 1-01 -0180 Hypersthene. 1-23
Na,O . 3-44 +0555
KoiOnnr cys) al 42 -0151 Maenetite . 0-09
HeO+ .. 0:80 -0444 Ilmenite . . 0:16
Hy O — 0-28 — Pyrite . 0-17
C O2 1-20 -0273
TviOpeee ee O09 -0011 Zireon . 0-04
Oro eae ee race —
Win) G6 6 . Ms0hs -0007 Dolomite . 1-66
Soy aan Mele ne O09 +0028 Calcite . 0-90
BHO) 5 6 a |) Weil —
YO o 5 6 OER -0002 Water . 0-40
100-40 100-42
Less O forS. 0-03 Less OforS . 0-03
Total . 100-37 Total . 100-39
The analysis is remarkable for the high percentage of silica that it
reveals. The highest percentage found in the estimations made for
Dr. Harker was 77:38, while in the specimen analysed by Mr. Barrow
the silica amounted to 71°60 per cent.1 The high alumina relative
to alkalies has been interpreted above. The abundance of soda
compared with potash justifies the name, albite-granophyre, applied
to the rock.
Arpire-Quartz-PorRPHYRY.
The distinguishing features of this rock have already been stated
above. The specimens are from one of those portions of the
‘‘ sranophyre’’ which ‘‘show little or no graphic structure at all,
the quartz and felspar forming an irregular mosaic. In this case the
quartz tends to occur partly in larger crystal-grains, and the rock
approximates to some quartz-porphyries”’. To this description” there
is little to add. The felspar is again albite, and quartz, which is
very abundant, corrodes the felspar and is itself corroded by the
groundmass. Muscovite occurs in larger wisps than in the grano-
phyre, and also forms curious vermicular aggregates in the ground-
mass. As in the granophyre the rock contains narrow veins of
quartz, and smaller ones containing carbonate minerals. The
remaining minerals were determined by separation with Thoulet
solution, using much more material than was available of the
granophyre. ‘The crop of heavy minerals proved to be identical with
that obtained from the latter, except that in the residue remaining
1 A. Harker, loc. cit., pp. 129-30.
2 Harker, loc. cit., p. 128.
Alfred Bell—Fossils of Hast Anglian Boxstones. 407
after treatment with a bar-magnet, a grain or two of brown
tourmaline was also found. ‘he specific gravity of both specimens
is 2°63, the same figure as that for the granophyre.
Mr. Hemingway states that the rock is very similar to the white
felsite interbedded in the Drygill shales to the north of Brandy Gill.
Gronogicat AGE.
It may be of interest to draw attention here to the recent work of
Mr. J. F. N. Green on the age of the Carrock Fell complex.' It is
well known that the complex is of later date than the Borrowdale
volcanic series. An upper limit is fixed by Mr. Green’s discovery of
granophyre fragments in the Watch Hill Beds. These consist of
shales and polygenetic grits which form a series of patches lying at
various horizons on the Skiddaw Slates between Cockermouth
(Watch Hill) and Great Sca Fell. Only one pebble of granophyre
was found at Watch Hill, but in the eastern exposures (i.e. in those
near to Carrock Fell) the rock was found to be invariably present in
the coarser bands of the series. Mr. Green shows that the Watch
Hill Beds are younger than the Borrowdale Series and older than the
Devonian earth-movements, and for these and other reasons he
correlates them with the Coniston Limestone Series. Consequently
he considers the igneous rocks of Carrock Fell to be pre-Bala.
Mr. Green concludes: ‘‘The Borrowdale Series is ascribed to the
Middle Lianvirn ... The Eskdale granite, Buttermere granophyre,
St. John’s granite-porphyry, and Carrick Fell complex all belong to
the suite, being intruded before the solfataric stage, but at a late
period of the episode.”
V.—Tue Fossits or tHE Hast Anotian Sus-Crae Boxsronezs.
By ALFRED BELL.
N the opening article of the GxronocicaL Magazine (Vol. I, p. 5,
1864) Mr. J. W. Salter remarks: ‘‘ An obscure but novel group
of organic remains comes to light in some well-worked district for
which we have as yet no fixed geological place,” and this description
may well apply to “ine fauna dealt with in the following pages.
Usually considered by geological writers as being ‘derived from
sources outside the Kast Anglian area, very little attention has been
paid to it, its environment, or to its Continental affinities. The
fossils hereafter referred to occur in a sandstone matrix’ more or
less consolidated, the relics of a former stratum afterwards broken
up, and now found distributed in places beneath the overlying
Pliocene deposits, between Walton-on-the-Naze and Hollesley on the
coast and inland to about Ipswich.
1 “The Age of the Chief Intrusions of the Lake District”’: Proc. Geol.
Assoc., xXvili, pp. 17-25, 1917.
2 Ibid., plate ii.
3 An interesting and important paper dealing with the petrology of the
Suffolk ‘‘ Boxstones ” (Crag), by Dr. P. G. H. Boswell, D.I.C., F.G.8. (now
_ Professor of Geology in the University of Liverpool), appeared in the
GroLogicaAL Macazine for June, 1915 (pp. 250-9, Plate X, and Figs. 1-3)
and may be consulted with advantage by readers of the present paper.
408 Alfred Bell—Fossils of Hast Anglian Boastones.
_ Within these boundaries the bed-rock is a floor of London Clay,
formerly covered by a higher zone of the same material, replete with
a fauna of similar type to that found at Sheppey, including fishes and
Crustaceans in fine preservation, the broken-up clay and the fossils
being deeply phosphatized. Upon this, again, there seems to have
been deposited a bed of sand of which the actual presence can only be
inferred, since it has not been found in situ as a separate strati-
graphical unit or stratum; but the suggestion is warranted by the
mass of debris yielding a particular group of fossils found in the
irregular blocks of indurated sandstone or loosely distributed in
the adjacent Crag sands, and in the tabular pieces present at
Trimley, Bucklesham, and other places, of which Dr. J. E. Taylor
writes in White’s History of Suffolk, 1874, “that it is not uncommon
to find slabs of the same kind of sandstone which appear to have
undergone little abrasion and to be in nearly the same condition they
were in when the formation to which they originally belonged was
broken up.” Similar pieces of sandstone with sharply defined
impressions of the fossils and shells, more or less unworn, may be
obtained occasionally during low tides at Bawdsey, where a bed of
the nodules may be seen at times near the Haven.
The petrology of the ‘‘boxstones” has been fully described by
Dr. Boswell, F.G.S., and the general features of the detritus by
myself.”
In the discussion following the reading of Professor Lankester’s
paper® “On the Newer Tertiaries of Suffolk and their Fauna”,
Sir C. Lyell pronounced the boxstones then produced as being similar
to those he had seen at Berchem, near Antwerp, in 1851,‘ in a deposit
of Rupelien age, the shells corresponding to those figured by
de Koninck in his well-known memoir‘ on the fossil shells of Basele,
Boom, etc.
This particular horizon has been referred by M. van den Broeck °
to the uppermost stage of the Middle Oligocene; a system largely
developed, according to von Koenen, Ravn, and other writers, in
Denmark, Belgium, and North-West Germany ; with a few exceptions
the boxstone species agree with those found in one or other of these
localities.
The English literature bearing upon the deposit and the faunas
associated with it before 1865 is very scanty. Charlesworth, in
1837, figured a tooth of Carcharias megalodon, with sundry notes on
the phosphatic nodules; and the so-called ‘‘Coprolites” and mammalia
recorded between then and 1851 are mentioned in the bibliography
appended to C. Reid’s Pliocene Deposits of Great Britain (1890).
The earliest descriptive account’ is that given by the Rev. W. B.
1 «« Petrology of the Suffolk Boxstones’’: op. cit.
2 “Sub-Crag Detritus”: Proc. Prehistoric Soc. East Anglia, 1915,
vol. xi, pp. 139-48.
3 Quart. Journ, Geol. Soc., vol. xxvi, pp. 493-513, 1870.
4 Quart. Journ. Geol. Soc., vol. viii, p. 282, 1852.
5 Mém. Acad. R. Sci. Bruxelles. vol. xi, 1837.
§ Bull. Soc. Belge Géol., vol. vii, p. 299, 1893.
7 Ann, Nat. Hist. (2), vol. viii, pp. 206-11, 1851.
Alfred Bell—Ffossils of Hast Anglian Boxstones. 409
Clarke, of Ipswich, on the nodule ‘‘bed”’ and its contents, figuring
amongst other items a ziphioid rostrum. This was apparently repro-
duced with other species in an early paper on Red Crag Mammals,’
by Professor Owen.
Mr. S. V. Wood was the first to recognize the shells in the
boxstones,” specifying several of these by name, but nothing further
was done till Professor Sir Ray Lankester, in 1865, briefly noticed
the deposit and, in 1868,3 discussed at some length its possible origin
and that of its contents.
Unfortunately for science, the closing of the ‘‘ Coprolite” industry
or phosphate diggings, and the little interest taken in the stones
when they were obtainable, limits the scope of our inquiry, and all
that can be done is to utilize the material at hand. This is chiefly
conserved in the Museums of Practical Geology, London, Ipswich,
Norwich, and York, and in one or two private collections, all of
which, by the courtesy of those in charge of them, it has been my
privilege critically to examine. I have also to thank the Trustees
of the Percy Sladen Memorial Fund for assistance in collecting
information.
The specimens upon which the following lists are founded
commonly occur as moulds of the exterior of the shells, showing the
sculpture, or as casts of the interior; the shelly matter being rarely
preserved. From these it has been possible by the use of wax or
gutta-percha to reproduce the general details of the organism, which
has been done by permission, from a number of the rarer and more
perfect examples, especially those in the York and Norwich Museums.
These will be ultimately added to those specimens already preserved
in the Museum of Practical Geology, London.
The fossils are so scattered that it may be useful to students to
know the Museums where they can be seen, and to have a reference
to some good figure of the shell referred to in the text. As a rule
the organisms have suffered little attrition, the sculptural details are
. well preserved, and most of the bivalves are found closed, as if
embedded alive before the muscles had become relaxed.
Boxstone Mollusca. |
Cylichna sp.
Cylichna cylindracea, Ravn, K. Danske Vid. Selsk. Skrift. (7), vol. iii,
p- 367, pl. viii, fig. 15, 1907. Mus. Pract. Geol. London, York.
Ringicula aurieulata, Menard.
Ringicula auriculata. Beyrich, Zeitsch. deutsch. Geol. Ges., vol. v, p. 330,
pl. v, fig. 18, 1853. Mus. Pract. Geol. London.
Ringicula striata, Philippi.
Ringicula striata, Philippi, Beit. tert. N.W. Deutschl., p. 28, pl. iv, fig. 23,
1843.
Ag », Ravn, K. Danske Vid. Selsk. Skrift. (7), vol. iii, p. 365,
pl. viii, fig. 11, 1907.
Mus. Pract. Geol. London.
1 Quart. Journ. Geol. Soc., vol. xii, 1856.
2 Crag Moll., pt. ii, 1851.
3 GuoL. Mac., Vol. II, pp. 103-49, 1865; Vol. V, p. 254, 1868.
410 Alfred Bell—Fossils of East Anglian Boxstones.
Conus Dwardini, Deshayes.
Conus Dujardim, Hornes, Foss. Moll. Tert. Wien, vol. i, p. 40, pl. vy,
fies. 3-8, 1856.
A 5 Lankester, Quart. Journ. Geol. Soc., vol. xxvi, p. 502,
pl. xxxiv, fig. 5, 1870.
Mus. Ipswich, Norwich.
Conus antediluvianus, var. B, Grateloup.
Conus antediluvianus, var. B, Grateloup, tee Conch. foss. de l’ Adour,
No. 44, fig. 6, 1840. Mus. Ipswich, York.
Conus cf. ventricosus, Bronn.
Conus ventricosus, Hérnes, Foss. Moll. Tert. Wien, vol. i, p. 32, pl. ili,
figs. 5-6, 1856.
ies = Fontannes, Moll. plioc. Vall. du Rhone, vol. i, p. 144,
pl. viii, fig. 11, 1887.
Mus. Ipswich.
Pseudotoma Mlorrent, de Koninck.
Pleurotoma Morreni (de Koninck), Coq. foss. Basele, 1837, p. 21, pl. i,
fig. 3. Mus. Ipswich.
[Mr. F. W. Harmer (Plioc. Moll. Gt. Brit., pt. ii, p. 212, regards this shell
as a variety of Pl. intorta, Brocchi, with which it has many points of
resemblance. |
Pleurotoma Steinvorthi, Semper.
Pleurotoma Steinvorthi, von Koenen, Mioc. nord-Deutschl., p. 94, pl. u,
fig. 10, 1872.
Ms 59 Norregaard, Dansk. Geol. Foren., vol. v, p. 138,
pl. ili, fig. 10, 1916.
Cancellaria (Trigonostoma) cf. ampullacea (Brocchi).
Voluta ampullacea, Brocchi, Conch. foss. Sub-ap., vol. ii, p. 313, pl. iii, fig. 9.
Trigonostoma ampullacea, Sacco, Moll. Tert. terz. Piem., pt. xvi, p. 9, pl. i,
figs. 16-20.
[Some imperfect forms at Ipswich may belong to C. wmbilicaris, Brocchi,
but as the aperture is not seen in either species, both ascriptions may need
revision. |
; Cancellaria (Ventrilia) aperta (Beyrich).
Cancellaria aperta, Beyrich, Zeitsch. deutsch. Geol. Ges., vol. vili, p. 586,
pl. xix, fig. 5, 1856. Mus. York.
Ancilla Nysti, F. W. Harmer.
Ancilla Nysti, F. W. Harmer, Plioc. Moll. Gt. Brit., pt. i, p. 52, oh xii,
figs. 32-3, 1913. Harmer Coll.
Voluta (Pyrgomitra) fusus (Philippi).
Fasciolaria fusus, Philippi, Beit. N.W. deutsch. tert., p. 25, pl. iv,
fig. 14, 1843.
Voluta parca, Beyrich, Zeitsch. deutsch. Geol. Ges., vol. v, p. 357, pl. vill, |
fig. 1, 1853. Mus. York, Ipswich. }
[‘These fisures represent the younger and older states of the shell. It has
a longer and narrower canal than the typical V. Lamberti of the Anglo- a
Belgian Crag basin. Dr. Mérch, in the Journ. de Conch., vol. xvii,
p. 428, 1869, assigns this ae to the sub-genus Pyrgomiira. |
ea a
Voluta (Pyrgomitra) sp.
Voluta cf. tarbelliana, var. ventricosa, Grateloup, Atlas Conch, foss. l’Adour, ,
pl. xxxix, fig. 2, 1840.
Voluta auris- lepori es Lankester, Quart. Journ. Geol, Soc., vol. xxvi, p. 502,
pl. xxxiv, fig. 6, 1870.
Mus. Ipswich.
5
a
4
Alfred Bell—Fossils of East Anglian Bowstones. 411
Mitra cf. fusiformis, Brocchi.
Mitra fusiformis, Cerulli-Irelli, Pal. ital., vol. xvii, p. 235, pl. xxi, fig. 19,
1911. Mus. Pract. Geol., London.
[The reference is founded on the cast of a long body and next whorl,
60 mm. long, 25 mm. broad, with a nearly straight figure. Mitra
Venayssina, Fontannes, Moll. Plioc. Vall. du Rhone, vol. i, p. 79, pl. vi,
fig. 1, is closely allied to it.]
Sipho gregarius (Philippi), pars.
Fusus gregarius, Beyrich, Zeitsch. deutsch. Geol. Ges., vol. viii, p. 59,
pl. v, figs. 7-8, 1856: Mus. Norwich, Ipswich.
Sipho lineatus (de Koninck).
Fusus lineatus, de Koninck, Coq. foss. Basele, p. 18, pl. iii, figs. 1, 2, 1837.
Mus. Pract. Geol. London, Ipswich, York.
Sipho muitisulcatus (Nyst).
Pusus multisulcatus, Nyst, Cog. foss. Belge, p. 494, pl. xl, fig. 1, 1848.
Mus. Pract. Geol. London.
[Nyst altered de Koninck’s specific name /ineatus to multisulcatus, but his
‘figure is not the same as de Koninck’s, which shows a shell having a longer
spire and canal, and narrower in proportion. They may be varieties of
a polymorphous form, but as both varieties occur in the boxstones they
are given accordingly for what they are worth. |
Sipho major, A. Bell.
Sipho major, A. Bell, Journ. Ipswich Field Club, vol. iii, p. 9, 1911.
Fusus erraticus, var., Harder, Danm. Geol. Uncereeer: vol, ii, p. 83, pl. vi,
Hor NLOTS.) «
Mus. Ipswich.
[This is a large shell, the three lower whorls measuring 80 mm. in length
with a breadth of 35mm. This and the next species may perhaps represent
a new group, intermediate between Sipho and Fasciolaria, as the moulds of
the upper whorls show traces of costal ornament. Of this group Fusus
(aff.) Konincki, Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii, pl. v, fig. 10,
might be taken as the type. ]
Sipho Ravni, sp. nov.
Fusus erraticus, var., Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii,
p. 333, pl. vi, fig. 13, 1907. Mus. Pract. Geol. London, Norwich.
Fasciolaria (Sureulofusus) erraticus (de Koninck).
Fusus erraticus, de Koninck, Coq. foss. Basele, p. 19, pl. ii, fig. 5, 1837.
56 en Nyst, Coq. foss. Belge, p. 496, pl. xl, fig. 2, 1843.
Mus. Pract. Geol. London, Ipswich.
Liomesus nudum (S. V. Wood).
Buccinum nudum, S. V. Wood, Mon, Crag Moll., Suppl. 2, p. 1, pl. i, fig. 1,
1879.
Liomesus ventrosus (Beyrich).
Fusus ventrosus, Beyrich, Zeitsch. deutsch. Geol. Ges., vol. vili, p. 35,
pl. il, figs. 3-5, 1856.
Buccinopsis Dalei, ar K. Danske Vid. Selsk. Skrift (7), vol. ili, p. 313,
pl. v, fig. 1, 1907.
Moore and Stanley Coll.
[Many of the shells found in the Scaldisien beds in Belgium figured as
B. Dalet, Sow., are much nearer to this species than to those in the English
Crag. Fig. 4 in Beyrich’s plate is an almost exact delineation of some of
the ‘Belgian forms. |
412 Alfred Bell—Fossils of Hast Anglian Boxstones.
Liomesus cf. danicus (von Koenen).
Buccinopsis danicus, Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii,
p. 313, pl. iv, figs. 10- 11, 1886. Mus. Pract. Geol., London.
[The shells figured by Ravn are both imperfect, and the London specimen
is referred to it with some doubt as only the dorsal aspect is exposed. It
is a rare shell on the Continent, as it is only recorded from the Danish
Oligocenes. ]
Cominella conica, sp. nov.
A smooth elongate bucciniform shell, channelled at the upper part of the
volutions. Whorls 5-6, rounded and sub-carinated. Apex blunt. Aperture
semilunate. Outer lip thickened, base but slightly prolonged. Umbilicus
exposed by the loss of shelly matter. Height 35 mm., breadth 20 mm.
Mus. Ipswich, Cambridge.
Desmoulea conglobata (aveesien
Buccinum conglobatum, Brocchi, Conch. foss. Subap., vol. i, p. 334, “sh iv,
fig. 15, 1814.
Nassa conglobata, S. V. Wood, Mon. Crag Moll., pt. i, p. 32, pl. iii, fig. 9,
1848.
Mus. Pract. Geol. London, York, Ipswich.
Semicassis saburon (Bruguicre).
Cassis saburon, Beyrich, Zeitsch. deutsch. Geol. Ges., vol. vi, p. 480, pl. xii,
fig. 5, 1854.
Cassidaria sp., Lankester, Quart. Journ. Geol. Soc., vol. xxvi, p. 502,
pl. xxxiv, fig. 8, 1870. :
In most collections.
Echinophoria sulcosa (Lamarck).
Cassis sulcosa, Hérnes, Foss. Moll. Tert. Wien, vol. i, p. 179, pl. xv, fig. 8,
1856.
Cassidaria sp., Lankester, Quart. Journ. Geol. Soc., vol. xxvi, p. 502,
plisexxiv, fie. Ieesi0:
Mus. Pract. Geol. London, Ipswich.
Echinophoria Rondeleti (Basterot).
Cassis Rondeleti, Basterot, Mém. Géol. sur les Env. de Bordeaux, p. 51,
pl. iii, fig. 22; pl. iv, fig. 13, 1825.
Cassis Rondeleti, Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii, p. 307,
pl. iv, fig. 9, 1907.
Mus. Ipswich.
[The late Mr. C. Reid includes Cassidaria bicatenata in his list of
Mollusca from the Suffolk boxstones. Plioc. Dep. of Britain, p. 13. It is
probably a clerical error. ]
Ficula acclinis (S. V. Wood).
Pyrula acclinis, 8. V. Wood, Mon. Crag Moll., pt. ii, p. 311, pl. xxxi, fig. 6,
1850. In most collections.
[The most characteristic feature of this species is the great breadth of
the upper part of the whorls. Pyrula condita in Hornes’ great work, vol. i,
pl. xxviii, fig. 4, seems to agree with Wood’s shell. ]
Ficula cingulata (Bronn).
Pyrula cingulata, Hérnes, Foss. Moll. Tert. Wien, vol. i, p. 676, pl. xxviii,
fig. 1, 1856 (figured as P. reticulata). Mus. Pract. Geol. London, York,
Ipswich.
Ficula condita (Brongniart).
Pyrula condita, Brongniart, Mém. sur les Terr. du Vicentin, p. 75, pl. vi,
fig. 4, 1823.
Alfred Bell—Fossils of Hast Anglian Boxstones. 418
Pyrula reticulata, 8. V. Wood, Mon. Crag Moll., pt. i, p. 42, pl. ii, fig. 12,
1848.
Mus. Pract. Geol. London, York, Ipswich.
Ficula cf. geometra (Borson).
Pyrula geometra, Hornes, Foss. Moll. Tert. Wien, vol. i, p. 271, pl. xxviii,
fig. 7, 8, 1856. Mus. Pract. Geol. London.
[A graceful cast in this museum may be assigned to this species with
some uncertainty. In form and outline, however, it corresponds to
Hornes’ and Sacco’s figures of the shell. ]
Pseudocassis spherica (Philippi).
Cyprea spherica, Beyrich, Zeitsch. deutsch. geol. Ges., vol. v, p. 319,
pl. iv, fig. 9, 1853. Mus. York.
[Mr. F. W. Harmer has in his collection a cast of a shell belonging to
this group, having the inner whorls coiled on a flat plane round the apex
as in some of the Conide, height 30 mm., breadth 20 mm., found at
Waldringfield. For the genus see Fischer, Manuel de Conchyliologie,
p. 668. ]
Trivia pisolina (Lamarck).
Cyprea pisolina, Lamarck (Deshayes), Anim. sans Vertebr., 2nd ed.,
vol. vii, p. 408, 1822.
Trivia pisolina, F, W. Harmer, Plioc. Moll. Gt. Brit., pt. i, p. 50, pl. ii,
fig. 17, 1913.
Moore Coll.
Rimella gracilenta (S. V. Wood).
Rostellaria (2) gracilenta, 8S. V. Wood, Mon, Crag Moll., Suppl. 3, p. 1,
pl. i, fig. 1, 1882. Mus. Ipswich.
Rimella lucida(?), (S. V. Wood), J. Sowerby.
Rostellaria lucida (?), S. V. Wood, Mon. Crag Moll., Suppl. 1, pt. i, p. 5,
pl. ii, fig. 14, 1872. Mus. Ipswich.
Rostellaria dentata, Grateloup.
Rostellaria dentata, Grateloup, Atlas Conch. foss. de l’Adour, No. 32, fig. 4,
1840.
Rs Se Cossmann, Ess. Paléoconch. compar., vol. vi, p. 19,
pl. ii, fig. 12, 138, 1904.
Mus. Ipswich.
Hippochrenes ampla Rutotr, var. nov.
Rostellaria ampla, Rutot, Ann. Soc. malac. Belge, vol. xi, p. 33, pls. i, ii,
. 1874. Mus. Norwich (spire), Ipswich (body).
Aporrhas speciosus (Schlotheim).
Aporrhais speciosus, Beyrich, Zeitsch. deutsch. geol. Ges., vol. vi, p. 492,
pl. xiv, figs. 1-3, 1854.
AS on Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii
p. 302, pl. iii, fig. 24, 1907.
’
Mus. Ipswich.
Cerithium acuticosta angulatior, Sacco.
Cerithium acuticosta, var. angulatior, Sacco, Moll. Terr. terz. Piemonte,
pt. xvii, p. 4, pl. i, fig. 6, 1895. Mus. Norwich.
Vermetus (Burtinella) Bognoriensis, Mantell.
Vermetus Bognoriensis (?), S. V. Wood, Mon. Crag Moll., pt. i, p. 114,
pl. xii, fig. 9, 1848. Mus. Ipswich.
[This shell (or annelid) is commonly diffused in the loose sands of the
older Red Crags, as well as in the hardened original matrix. §. V. Wood,
Suppl. 3, p. 1.]
414 Alfred Bell—Fossils of East Anglian Boxstones.
Vernuilia flagelliformis (Morris).
Serpula flagelliformis, J. Sowerby, Min. Conch., vol. vii, p. 50, pl. Dexxxiv,
figs. 2, 3, 1844. Attached to shell of Pectunculus. Mus. York.
Turritella Geinitzi, Speyer.
Turritella Geinitzi, Speyer, Paleontographica, vol. xvi, p. 22, pl. ii, fig. 2,
1866.
A ,, . Norregaard, Danske Geol. Forening, vol. v, p. 122,
pl. ii, fig. 7, 1916.
Xenophora Deshayest (Michelotti).
Xenophora Deshayesi, Hérnes, Foss. Moll. Tert. Wien, vol. i, p. 442,
pl. xliv, fig. 12, 1856.
as 3 Sacco, Moll. Terr. terz. Piemonte, pt. xx, pl. ii,
fig. 20, 1896.
Mus. Ipswich.
Mus. Pract. Geol. Londoa.
Xenophora serutarva (Philippi).
Trochus scrutaria, Philippi, Beit. Tert. N.W. Deutschlands, p. 22, pl. iii,
fig. 37, 1843.
Xenophoria scrutaria, Speyer, Paleontographica, vol. xvi, p. 328, pl. xxxiv,
fig. 8, 1866.
Mus. Pract. Geol. London.
Natica achatensis (Recluz MS.), de Koninck.
Natica achatensis, de Koninck, Coq. foss. Basele, p. 9, 1837.
Natica glaucinoides, Nyst, Coq. foss. Belge, p. 442, pl. xxxvil, fig. 32, 1843.
Mus. Pract. Geol. London, York, Ipswich.
Natica Nysti, cf. D’Orbigny. j
Natica Nysti, Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii, p. 293, pl. iii,
fig, 10, 1907. In most collections.
Natica cf. hantoniensis, Pilkington.
Natica hantoniensis, von Koenen, Paleontographica, vol. xvi, p. 148, pl. xii,
fig. 9, 1867.
Pi ae Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii,
p. 290, pl. iii, fig. 6, 1907.
Mus. York,
[This fine cast, height 33 mm., breadth 25mm., is clean from any
adventitious matter. Its globose form and straightness of columella
indicate its connection with the above species. Unfortunately the outer
mould was not preserved. | :
Natica (Crommium) ferruginea italica (Sacco).
Crommium ferrugineum italica, Sacco, Moll. Terr. terz. Piemonte, pt. ix,
p. 8, pl. i, fig. 8, 1891. Mus. Pract. Geol. London, Ipswich.
Natica elongata, Michelotti.
Natica elongata, Michelotti, Et. Mioc. Inf. d’Italie, p. 88, pl. x, fig. 34, 1861.
Euspirocrommium elongatum, Sacco, Moll. Terr. terz. Piemonte, pt. ix,
p. 10, pl. i, fig. 11, 1891.
Stanley Coll.
iso sp.
[The cast referred to this genus exhibits the perforated axis very clearly,
and is probably that of one of the many forms of Niso (Bonellia) terebellata,
Grateloup, figured by Sacco, Moll, Terr. terz. Piemonte, pt. xi, pl. i,
figs. 39-52. Harmer Coll.]
Alfred Bell—Fossils of Hast Anglian Boxstones. 415
Bolma granosa mioceniea, Sacco.
Bolma granosa miocenica, Sacco, Moll. Terr. terz. Piemonte, pt. xxi, p, 13,
pl. i, fig. 28, 1896. Mus. Pract. Geol. London.
Phoreus striatus, Risso.
Phorcus striatus, Risso, Hist. Nat. Eur. merid., vol. iv, p. 134, 1826.
[Risso’s diagnosis of this species, which he only knew as fossil, equally
describes the boxstone shell, so as to render them practically identical.
Mus. Ipswich. ]
Calliostoma millegranus precedens (von Koenen).
Trochus labarum (?), Basterot, Mém. Géol. de ’Hnv. de Bordeaux, 1825,
p. 33, pl. i, fig. 23.
Trochus iniliaria, Hérnes, Foss. Moll. Tert. Wien, vol. i, p. 454, pl. xlv,
fig. 9, 1856.
Trochus millegranus preecedens, von Koenen, Mioc. N. Deutschlands
(Marburg), p. 308, 1872.
Mus. Pract. Geol, London.
Calliostoma Xaviert (Costa MS.). |
Trochus Xaviert, Dollfus, Cotter, & Gomes, Moll. tert. du Portugal, p. 6,
pl. xxxi, fig. 4, 1903.
Zizyphinus opisthosthenus, cf. Fontannes, Moll. Plioe. de la Vall, du Rhone,
vol. i, ps 218; p. xi, fig. 22; 1897.
Mus. Ipswich.
Dentalium sp.
(2?) Dentalium fossile, Hérnes, Foss. Moll. Tert. Wien, vol. i, p. 657, pl. i,
fig. 36, 1856. Stanley Coll.
Dentalium Kickaui, Nyst.
Dentalium Kickxii, Nyst, Coq. foss. Belge, p. 342, pl. xxxvi, fig. 1, 1843.
ef » Ravn, K. Danske Vid. Selsk. ‘Skrift (7), vol. iii, p. 286,
pl. iii, fig. 4, 1907.
Mus. Pract. Geol. London.
Spondylus sp.
[The genus is represented by a perfect upper valve with the inner side
exposed showing the characteristic dentition. It is recorded from the
Belgian Oligocenes. See Vincent, Ann, Soc. malac. de Belge, vol. xxiii,
1888. Mus. York.]
Pecten (Chlamys) Malvine, Dubois de Montperoux.
Pecten Malvine, Dubois de Montperoux, Coq. foss. Wolhyma, p. 71, pl. viii,
figs. 2-3, 1831.
Ae si Hornes, Foss, Moll. Tert. Wien, vol. ii, p. 414, pl. lxiv,
fig. 5, 1870.
Stanley Coll.
Pecten (Chlamys) Sollingensis, von Koenen.
Pecten Sollingensis, von Koenen, Paleontographica, vol. xvi, p. 228, pl. xxvi,
figs. 7, 8, 1867.
fa Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii, p. 251,
pl. i, fig. 1, 1907.
Mus. Pract. Geel. London.
Pecten (Chlamys) Hoeninghausi, Defrance.
Pecten Hoeninghausit, Nyst, Coq. foss. Belge, p. 286, pl. xxii, fig. 2, 1843.
Pecten disparatus, S. V. Wood, Mon. Crag Moll. , Suppl. 3, p. 12, pl. i, fig. 17,
1882.
Stanley Coll., Brit. Mus. (Nat. Hist.) London.
Pecten (Chlamys) substriatus, D’Orbigny.
Pecten substriatus, Hérnes, Foss. Moll. Tert. Wien, vol. ii, p. 408, pl. Ixiv,
fig., 1870. Harmer Coll.
416 Alfred Bell—Fossils of East Anglian Boxastones.
Pecten (Chlamys) rupeliensis (von Koenen).
Pecten rupeliensis, von Koenen, Paleontographica, vol. xvi, p. 232, pl. xxvi,
fig. 12, 1867. Mus. Pract. Geol. London, Stanley Coll.
Pecten (Chlamys) cf. Hrslevt, Harder.
Pecten Erslevi, Harder, Danm. geol. Underseg., vol. ii, p. 44, pl. iii, figs. 3, 4,
1913. Mus. Pract. Geol. London.
[A fragment in the M.P.G. seems to agree with Harder’s figure. ],
Pecten (Peplum) sp.
Pecten verrucopsis, de Gregorio, Ann. de Geol., pt. xiii, p. 26, pl. iv, figs. 89,
90, 1894.
Pecten clavatus, Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii, p. 252, pl. i,
fig. 2, 1907.
Mus. Pract. Geol. London.
[Of the two figures cited above, Gregorio’s comes nearest to the M.P.G.
fragment. | ;
Pecten (Chlamys) excisus, Bronn.
Chlanys excisus, Dollfus & Cotter, Moll. Tert. du Portugal, 1909, p. 77,
pl. viii, figs. 5-9.
[I found a characteristic fragment of this species in Newbourne Crag pit.]
Hinnites erispus (Brocchi).
Hinnites crispus, Sacco, Moll. Terr. terz. Piemonte, pt. xxix, p. 10, pl. ii,
fig. 1, 1897. Stanley Coll.
Pinna pectinata Broccht (D’Orbigny).
Pinna Brocchi, Hornes, Foss. Moll. Tert. Wien, vol. ii, p. 372, pl. i,
figs. 1, 2, 1870.
Pinna pectinata Brocchi, Sacco, Moll. Terr. terz. Piemonte, pt. xxv, p. 29,
pl. viii, fig. 1, 1898.
Mus. York, Stanley Coll.
Mytilus corrugatus, Brongniart.
Mytilus corrugatus, Brongniart, Mém. sur les tert. du Vicentin, p. 78, pl. v,
fig. 6, 1823. Stanley Coll.
Arcoperna sericea (Bronn).
Modiola sericea, Philippi, En. Moll. Sic., vol. i, p. 71, pl. v, fig. 14, 1836.
S. V. Wood, Mon. Crag Moll., pt. ii, p. 61, pl. viii, fig. 3,
1850.
99 29
Mus. Ipswich.
Pectunculus Philippi, Deshayes.
Pectunculus pulvinatus, var., Philippi, Beit. N.W. deutsch. tert., p. 13, pl. ii,
fig. 13, 1843.
Pectunculus Philippi, Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii, p. 262,
pl. i, fig. 17, 1907.
Mus. Ipswich.
Pectunculus Bormidianus, Mayer.
Pectunculus Bormidianus, Mayer, Foss. Mus. Zurich, pt. iii, p. 49, 1868.
Aximea Bormidiana, Sacco, Moll. Terr. terz. Piemonte, pt. xxvi, p. 37,
pl. ix, figs. 11-15, 1898.
Mus. Norwich, etc.
Pectunculus inflatus (Brocchi).
Arca inflata, Brocchi, Conch. foss. Subap., p. 494, pl. xi, fig. 7, 1814.
Aginea inflata, Sacco, Moll. Terr. terz. Piemonte, pt. xxvi, p. 32, pl. viii,
figs. 1-6, 1898.
In most collections.
Alfred Bell—Fossils of East Anglian Boxstones. 417
[Pectunculus pilosus and P. glycimeris ave amongst the commonest forms
in the boxstones, and probably other members of this variable group are
present. |
Nucula donaciformis, Harder.
Nucula donaciformis, Harder, Danm. geol. Underseg., vol. ii, p. 49, pl. iii,
fig. 10, 1913. Stanley Coll.
Nucula placentina, Lamarck.
Nucula placentina, Philippi, Hn. Moll. Sic., vol. i, p. 65, pl. v, fig. 7, 1836.
re As Sacco, Moll. Terr. terz. Piemonte, pt. xxvi, p. 46, pl. x,
figs. 35-40, 1898.
Mus. Ipswich.
Nucula Haesendonckii, Nyst & Westendorp.
Nucula Haesendonckiu, Nyst, Coq. foss. Belge, 1843, p. 236, pl. xviii, fig. 5.
{Sir E. Ray Lankester informs me that he had identified this very distinct
species in the collection of the late Dr. Taylor in Ipswich. Unfortunately the
specimen has been lost sight of.]
Nucula turgens, S. V. Wood.
Nucula turgens, 8. V. Wood, Mon. Crag Moll., Suppl. 2, p. 44, pl. v, fig. 6,
1879. Mus. Brit. Nat. Hist., Wood Coll.
Leda Deshayesiana (Du Chastel Coll.).
Nucula Deshayesiana, Nyst, Coq. foss. Belge, p. 221, pl. xv, fig. 8, 1843.
Leda Deshayesiana, Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii, p. 258,
pl. i, figs. 7, 8, 1907.
Stanley Coll.
Venericardia antiquata rhomboidea (Brocchi).
Chama rhomboidea, Brocchi, Conch, foss. Subap., p. 523, pl. xii, fig. 16, 1814.
Cardita (Glans) rhomboidea, Cerulli-Irelli, Pal. ital., vol. xiii, p. 135, pl. xii,
fig. 28, 1907.
Mus. York.
Astarte Henckeliusiana, Nyst.
Astarte Henckeliusiana, Nyst, Coq. foss. Belge, p. 154, pl. ix, fig. 4, 1843.
von Koenen, Palwontographica, vol. xvi, p. 250,
pl. xxix, fig. 7, 1867. :
9 29
Mus. Pract. Geol. London.
Astarte Kickxuw, Nyst.
Astarte Kickxit, Nyst, Coq. foss. Belge, p. 157, pl. x, fig. 3, 1843.
Astarte Kicksii, Ravn, K. Danske Vid. Selsk. Skrift (7), vol. iii, p. 268, pl. i,
fig. 21, 1907.
Mus. Pract. Geol. London, Stanley Coll.
Astarte cf. solidula, Deshayes.
Astarte solidula tawroscalarata, Sacco, Moll. Terr. terz. Piemonte, pt. xxvii,
p- 25, pl. vi, fig. 29,1899. Mus. Pract. Geol. London.
[Length 18mm., breadth 22 mm.; sculpture, 6 or 7 thick concentric ribs.
The number of these vary according to Sacco’s figures of A. solidula. |
Cardium cingulatum, Goldfuss.
Cardium cingulatum, Goldiuss, Petr. Germ., vol. ii, p. 222, pl. exly, fig. 4,
1838.
uA Hérnes, Foss. Moll. Tert. Wien, vol. ii, p. 177,
pl. xxv, fig. 1, 1870.
Mus. York, Ipswich.
[C. venustum, Lamk., non S. V. Wood, and C. wmbonatuwm, A. Bell,
non Sowerby. |
DECADE VI.—VOL. IV.—NO. IX. 27
418 Alfred Bell—Fossils of Hust Anglian Boustones.
Cardium Woolnoughi, sp. nov.
[The species here referred to is not rare, but does not appear to have been
figured or described by any Continental writer. In shape it is roundly ovate,
tumid, and nearly equilateral, garnished with twenty-five to thirty narrow
rounded prominent ribs continued below the lower margin with rather wider
interspaces. The surface is much decorticated, leaving four or five ridges
marking probably stages of growth. Mus. Ipswich. ]
Cardium subdecorticatum, A. Bell.
Cardiuwm subdecorticatum, A. Bell, Journ. Ipswich Field Club, vol. iii, p. 9,
1911.
Cardium ci. decorticatum tenellum, S. V. Wood, Mon. Crag Moll., pt. ii,
p-. 159, pl. xiv, fig. 1d, 1850.
In most collections.
[The above shell is decorticated as in Wood’s figure, but the ribs are more
open=C. decorticatwm of Lankester and Reid. ]
Lsocardia cor (Linné).
Isocardia cor, S. V. Wood, Mon. Crag Moll., pt. ii, p. 193, pl. xv, fig. 9, 1850.
an ,, Forbes & Hanley, Brit. Moll., vol. i, p. 472, vol. iv, pl. xxxiv,
fig. 2, 1853.
Mus. York, Ipswich.
Lsocardia lunulata, Nyst.
Tsocardia lunulata, Nyst, Coq. foss. Belge, p. 198, pl. xv, fig. 2, 1843.
Ms Ae Lankester, Quart. Journ. Geol. Soc., vol. xxvyi, p. 502,
pl. xxxiy, fig. 10, 1870.
In all collections.
»Cyprina tumida, Nyst.
Cyprina tumida, Nyst, Coq. foss. Belge, p. 148, pl. x, fig. 1, 1843.
Cyprina rustica (tunvida), S. V. Wood, Mon. Crag Moll., pt. ii, p. 197, pl. xviii,
fig. 1, 1850.
: Mus. York.
Cyprina scutellaria (Lamarck).
Cyprina scutellaria, Nyst, Cog. foss. Belge, p. 145, pl. vii, fig. 5; pl. viii,
fig. 1, 1843. In most collections.
Cyprina wslandica equalis (J. Sowerby).
Cyprina equalis, Goldfuss, Petr. Germ., p. 236, pl. exlviii, fig. 5, 1838.
Cyprina islandica, 8. VY. Wood, Mon. Crag Moll., pt. ii, p. 196, pl. xviii,
figs. 2a, b, 1850.
Cyprina islandicoides, Lamarck.
Venus islandicoides, Hornes, Foss. Moll. Tert. Wien, vol. ii, p. 121, pl. xiii,
fig. 2, 1870.
Anmiantis islandicoides, Sacco, Moll. Tert. terz. Piemonte, pt. xxviii, p. 21,
pl. v, figs. 1-4, 1900.
Meretrix chione, Linné.
Meretrix (Callista) chione elongata, Bucquoy, Dollfus, & Dautzenberg, Moll.
du Roussillon, vol. ii, p. 328, pl. lii, fig. 10, 1893.
Meretrix (Callista) chione, Cerulli-Irelli, Pal. ital., vol. xiv, p. 43, pl. viii,
figs. 9, 10, 1908.
Moore Coll.
[Major Moore has in his collection a fine mould of the interior of a shell,
corresponding to the above, found at Waldrinefield. ]
Alfred Bell—Fossils of Hast Anglian Boxstones. 419
Ventricola multilamella (Lamarck), var. Bory’, Deshayes.
Venus sp., Lankester, Quart. Journ. Geol. Soc., vol. xxvi, p. 502, pl. xxxiy,
fig. 7, 1870.
Ventricola multilamella, Boryt, Sacco, Moll. Terr. terz. Piemonte, pt. xxviii,
p. 31, pl. viii, fig. 9, 1900.
Mus. Ipswich, Stanley Coll.
[The ‘‘boxstone’’ mould so closely approximates to the shell figured by
Sacco that it may be regarded as the same species; the more so because
V. nvultilamella is somewhat variable in outline. |
Meretriz (Callista) fragilis (Minster).
Venus fragilis, Goldfuss, Petr. Germ., vol. ii, p. 247, pl. exlviii, fig. 8, 1840.
Venus circularis, A. Bell, Journ. Ipswich Field Club, vol. iii, p. vii, 1911.
Mus. Ipswich.
Meretriz (Callista) suborbicularis (Goldfuss).
Venus suborbicularis, Goldfuss, Petr. Germ., vol. ii, p. 247, pl. exlviii, fig. 7,
1840. Mus. Ipswich.
[The shell quoted or figured by Koninck, Nyst, Ravn, and other writers as.
Venus or Meretrix mcrassata, Sow., does not seem to be the same as the
English shell of that name. |
Tapes vetula (Basterot).
Venus vetula, Basterot, Mém. géol. sur les Hny. de Bordeaux, p. 89, pl. vi,
fig. 7, 1825.
Tapes vetulus, Dollfus & Dautzenberg, Mém. Soc. géol. France, vol. xiv,
p. 176, pl. ii, figs. 1-6, 1906.
Mus. Pract. Geol. London.
Donax minutus, Bronn.
Donax minutus, Sacco, Moll. Terr. terz. Piemonte, pt. xxix, p. 4, pl, i,
figs. 8,9, 1901. Mus. Pract. Geol. London, Ipswich.
Solenocurtus Basteroti, Desmoulins.
Solenocurtus Basterott, Sacco, Moll. Terr. terz. Piemonte, pt. xxix, p. 15, ~
pl. iv, fig. 1, 1901.
a i Dollfus, Cotter, & Gomes, Moll. tert. Portugal,
p. 27, pl. i, figs. 7-10, 1903.
Mus. Pract. Geol. London.
Solen (Ensis) cf. Rollei (Hornes).
Hnsis Rollei, Hérnes, Foss. Moll. Tert. Wien, vol. ii, p. 15, pl. i, fig. 14, 1870.
a » Dollfus & Dautzenberg, Mém. Soc. géol. France, vol. x, p. 65,
pl. ix, figs. 35-8, 1902.
Mus. Ipswich.
Mactra miocenica, Dollfus & Dautzenberg.
Mactra niocenica, Dollfus & Dautzenberg, Mém. Soc. géol. France, vol. xi,
p- 109, pl. vi, figs. 10, 11, 1904. Mus. Pract. Geol. London, Ipswich.
[M. podolica, Hornes, Foss. Moll. Tert. Wien, vol. ii, p. 62, pl. vii, fig. 5,
may be a variant of this species. |
Mactra triangula, Renier.
Mactra triangulata, S. V. Wood, Mon. Crag Moll., 1850, pt. ii, p. 325,
pl. xxi, fig. 21. Stanley Coll.
Mactra trinacria, Speyer, Paleontographica, vol. xvi, p. 34, pl. iii, fig. 4,
1861. Mus. Pract. Geol. London, York.
(The principal difference between M. triangulata and M. trinacria seems
to be that the latter forms a more equilateral triangle than the other. Both
are probably related to the recent M. elliptica.]
420 Alfred Bell—Fossils of East Anglian Boustones.
Lutraria sanna, Basterot.
Lutraria sanna, Basterot, Mém. géol. sur les Eny. de Bordeaux, p. 94, pl. vii,
fig. 13, 1825.
- an Sacco, Moll. Terr. terz. Piemonte, pt. xxix, p. 31, pl. viii,
fig. 5, 1901.
Mus: Pract. Geol. London, Ipswich.
Lutraria ovalis, sp. nov.
Lutraria sanna, Hoérnes, Foss. Moll. Tert. Wien, vol. ii, p. 56, pl. v, fig. 5,
870.
a ne Dollfus, Cotter, & Gomes, Moll. tert. du Portugal, p. 30,
pl. iv, fig. 4, 1903.
[Allied to L. oblonga, Chemnitz. ]
Lutraria elliptica Jeffreysii, De Gregorio.
Lutraria elliptica Jeffreysi, De Gregorio, Boll. Soc. malac. ital., vol. x,
p. 143.
Lutraria lutraria Jeffreysi, Cerulli-Irelli, Pal. ital., vol. xv, p. 143, pl. xv,
fig. 9, 1909.
Mus. Pract. Geol. London, Norwich, Ipswich.
Corbulomya complanata, var. B, Nyst.
Corbulomya complanata, Nyst, Coq. foss. Belge, p. 59, pl. ii, fig. ii, 1843.
Stanley Coll. ,
Panopea Menardi, Deshayes.
Panopea Menardi, Hérnes, Foss. Moll. tert. Wien, vol. ii, p. 29, pl. ii,
figs. 1-8, 1870.
Glycimeris Menardi, Sacco, Moll. Terr. terz. Piemonte, pt. xxix, p. 43, pl. xii,
_ fig. 4, 1901.
In most collections.
Panopea deciivis, Michelotti.
Lutraria declivis, Michelotti, Etud. Mioc. Inf. d’Ital., p. 57, pl. vi, fig. 1, 1861.
Glycimeris intermedia declivis, Sacco, Moll. Terr. terz. Piemonte, pt. xxix,
p. 45, pl. x, fig. 6, 1901.
Mus. Pract. Geol. London.
Panopea Gastaldi (Michelotti).
Panopea Gastaldi, Michelotti, Etud. Mioc. Inf. d’Ital., p. 54, pl. v, fig. 10,
1861.
Glycimeris intermedia Gastaldi, Sacco, Moll. Terr. terz. Piemonte, pt. xxix,
p. 45, pl. x, fig. 4, 1901. Mus. Ipswich.
Panopea(?) acutangula (Michelotti).
Lutraria acutangula, Michelotti, Etud. Mioc. Inf. d’Ital., p. 57, pl. vi,
fig. 2, 1861.
Glycimeris intermedia acutangula, Sacco, Moll. Terr. terz. Piemonte, pt. xxix,
p. 46, pl. xii, fig. 10, 1901.
Mus. Ipswich.
Cyrtodaria vagina (S. V. Wood).
Glycimeris avgusta, 8S. V. Wood, Mon. Crag Moll., pt. ii, p. 291, pl. xxix,
fig. 2, 1850. Mus. Pract. Geol. London.
[I do not think this to be the same shell as the Glyc. angusta of Nyst’s
memoir, pl. ii, fig. 1. The latter has a more pointed extremity. This I have
had from the Red Crag. Mr. Stanley has a small shell in his sandstone
collection from Bawdsey which may be the same. ]
Alfred Bell—Fossils of East Anglian Boxstones. 421
Lucina (Dentilucina) Barrandei, Mayer.
Lucina Barrandei, Mayer, Journ. de Conch., vol. xix, p. 340, pl. x, fig. 1,
1871.
Dentilucina Barrandet, var., Sacco, Moll. Terr. terz. Piemonte, pt. xxix, p. 83,
pl. xix, figs. 7-9, 1901.
Lucia Canhanu, A. Bell, Journ. Ipswich Field Club, vol. iii, p. 9, 1911.
Mus. Ipswich.
Syndosmya sp.
[Two or three species of this group are present in the ‘‘boxstones’’,
possibly the Hrycina longicallis and H. similis, figured in Philippi, En. Moll.
Sic., vol. ii, pl. xiii, figs. 7, 8, but they are not sufficiently definite for accurate
determination. Stanley Coll.]
Syndosmya prismatica (Montagu).
Ligula donaciformis, Nyst, Coq. terr. Belge, p. 92, pl. iv, fig. 9, 1843.
Abra prismatica, 8. V. Wood, Mon. Crag Moll., pt. ii, p. 239, pl. xxii, fig. 13,
1850.
Mus. Pract. Geol. London, York.
Thracia ventricosa, Philippi.
Thracia ventricosa, Philippi, Hn. Moll. Sic., vol. ii, p. 17, figured in vol. i,
pl. i, fig. 10 (as 7. pubescens), 1844.
Thracia ventricosa, §S. V. Wood, Mon. Crag Moll., Suppl. 2, p. 48, pl. v,
fig. 3, 1879.
Mus. Ipswich.
Teredo borings in wood are not uncommon, but the shells have
entirely disappeared.
[Certain shells of pre-Crag origin are found in the Oakleyan and Newbournian
zones of the Red Crag, and as some of these also occur embedded in the box-
stones they are presumably of the same age.
Most of these are figured by Mr. S. V. Wood in the Supplements to the Crag
Mollusca, and by Mr. F. W. Harmer in the Monograph on the Pliocene
Mollusca now in course of publication.
A few like the Rimelle, Serpule, Turritelle, and Venericardia occur
in profusion, but as a rule the majority are single specimens, as in the
following list :—
Borsonmia suffolciensis. Purpura derwata.
Pleurotoma denticulata. Stenomphalus Weichmannt.
a mterrupta. Triton connectens.
nA nodifer. Ranella (?) anglica.
we plebeia. Semicassis saburon.
59 Selysw. Fiumella, two or three species.
Cancellaria evulsa. Turritella, two or three species.
Ancillaria glandiformis. Solarwum, two or three species.
Volutilithes luctatria. Ostrea, two or more species.
i LODOSG. Pecten Heninghausw.
* suturalis. ,, Sollongensis.
Mitra fusiforniis (?). Venericardia, several varieties.
Fusus abrasus. Lucima crassidens.
BT CTLSOUS:
I have not seen any specimens of the typical Voluta Lamberti of the English
or Belgian Crags, or of Pyrula (Ficula) reticulata, or Cassidaria bicatenata in
the ‘‘boxstones’’. The latter, however, is said to occur sparingly in the
“Sables noirs d’Anvers ’’.
Voluta Lamberti, Atractodon elegans, and Cassidaria bicatenata are occa-
sionally washed ashore on the coast, from Aldborough to Walton-on-the-Naze,
422 Notices of Memoirs—Dr. A. S. Woodward—
derived from some deposit probably of Diestian or Anversian age. Mr. Harmer
has in his collection a worn shell of the V. Lamberts group, showing distinctly
broad and swollen ribs on the upper whorls obtained from the Felixstowe shore.
Very few invertebrate remains other than the Mollusca have been obtained
in the Hast Anglian area. I have only noticed, or found recorded :—
Crustacea.
Celoma sp. (? rwpeliense, Strainer), and segments of a narrow lobster-like
species,
Balanus inclusus (fide Lankester), B. wnguiformis.
Radiata.
Cyphosoma tertiariwm, Cotteau.
Diadema megastoma, A. Bell.
Solaster Reed, n.sp.
[This unique example belongs to the Reed Collection in the York Museum.
It exhibits the dorsal surface of a thick fleshy starfish, covered with bunches
of short fasciculate spines scattered over the surface, as they are in the recent
S. furcrfer.
Mr. W. K. Spencer, F.G.S., has kindly furnished me with the following
notes of dimensions: ‘‘ Major radius 33 mm. (approx.), minor radius 13 mm.,
width of arm at base 14 mm., no. of arms six.’’]
Celenterata.
Filabellum cuneata, Goldfuss, and another species.
Solenastrea Prestwichii, Duncan.
Trochocyathus anglicus, Duncan.
Woods, fruits, and nuts are common in the Belgian Rupelien deposits, and
our sub-Crags are rich in these. Mr. W. Carruthers told me many years
ago that he had determined three Angiospermous Dicotyledons, one conifer,
and two palms. Certain plants or fruits retain their forms when phosphatized
both in exterior shape and internal structure, but whether these have any
relations to either of the woods present is not yet known. Mus. Ipswich,
Saffron Walden.
Amber has been obtained from the Cromer Forest Bed, and Mr. C. Reid
has referred to a variety of spiders, insects, etc., in amber washed up
on the East Anglian coast, Trans. Norfolk and Norwich Nat. Hist. Soc.,
vols. iii-v. Mr. A. H. Foord, F.G.S., in vol. v, p. 92, figures many of these,
including bees, beetles, cockroaches, and spiders, submitted to, and partly
named by, Mr. C. O. Waterhouse and the Rev. O. P. Cambridge. Whether of
the same age as the above woods has yet to be determined.
NOTICHS OF MEMOTRS.
T.—On Mammatran Bonrs From Excavations in THE Lonpon
Disrercr. By Arruur Surrx Woopwarp, LL.D., F.R.S.
ie an area so long populated as the London district the surface
deposits are naturally very varied, and those of the historic
period contain remains not only of the indigenous fauna but also of
man’s accidental importations. ven so late as the twelfth century
William Fitzstephen wrote that the woods close to the city were
well stocked with game—“ stags, fallow-deer, boars, and wild bulls.”
Their bones and teeth are often found, besides the remains of other
animals, perhaps partly of somewhat earlier date, among which the
beaver is especially interesting. Bones of the beaver are indeed so
1 Abstract of a lecture delivered to the South-Eastern Union of Scientific
Societies at Burlington House, London, on June 7, 1917.
Fossil Mammalia in London District. 423
abundant in the marsh deposits of the Lea Valley, Essex, that this
animal probably had much to do with the extension of the swamps in
that region. A good skeleton of a beaver was found in 1911 when
excavating at the Royal Victoria and Albert Docks.
Until comparatively recent times much of the land now covered
with houses was occupied by market gardens, which it was customary
to ornament with trophies brought home by sailors. Among these
may be specially mentioned the ribs and jaws of whales, which were
erected as arches or made into seats, and disappeared by burial as
soon as building operations began. Remains of the oxen, sheep, and
pigs used for food were also often buried, and heaps of them have
been found in some places, such as Moorfields. They should be
- collected with care when circumstances allow of their being dated,
because it is interesting to determine the successive breeds which
they represent. Exceptional accumulations of bones are sometimes
puzzling and less easily explained than one which I saw in the mud
filling a former pond at Earl’s Court House when it was dismantled
in 1884. Here lived the eminent surgeon John Hunter, who thus
disposed of the remains of many of the carcases he dissected.
Below the very irregular surface deposits of London there are the
old gravels, with associated sand, brick-earth, and peat, of Pleistocene
age, occurring at different levels above the Thames, which laid them
down before it had cut out the valley to its present depth. Excava-
tions in these river terraces yield mammalian bones almost
every where.
Sometimes a cold or Arctic fauna is met with. A fine large antler
of reindeer and part of the frontlet of a bison were dug up in
Buckingham Palace Road in 1891, and similar remains were again
found associated at Twickenham in 1894. With the latter Dr. J. R.
Leeson discovered a characteristic frontlet of the saiga antelope,
which lives now only on the steppes to the east of the Volga. A still
more Arctic animal, the musk-ox, is represented in the British Museum
_ by fragments from Plumstead Marshes, Crayford, and Maidenhead.
Remains of the mammoth (Elephas primigenius) occur abundantly,
and some of the best specimens have been found at the bottom of
the Thames deposits, directly on the London Clay. Several parts
of the skeleton of a young mammoth were discovered thus in an
excavation at Endsleigh Street, Bloomsbury, in 1892. More
fragmentary remains of the same animal were dug up in 1908 and
1909 in a peaty bed on the London Clay beneath the Daily Chronicle
office, Fleet Street, associated with very fine skulls of old and young
individuals of the woolly rhinoceros (Rhinoceros antiquitatis), which
were given to the British Museum by Mr. Frank Lloyd. More
recently part of the humerus of a lion has been found in the same
deposit.
Evidence of a warmer Pleistocene fauna occurs in several places,
and the collection of bones and teeth obtained in 1879 from the
foundations of Drummond’s Bank, Charing Cross, may be mentioned
in illustration. I am indebted to Mr. Charles Drummond and the
Manager of the Bank for the opportunity of examining this collection,
which is still preserved there. The lion is represented by three
424 Noteces of Memoirs—Origin of Tertiary Man.
vertebra, part of a sacrum, the middle piece of a humerus, and
acaleaneum. There is a characteristic molar tooth of the southern
elephant, Elephas antiquus, while three fragments of tusk and some
portions of limb-bones may well belong to the same species. Two
bases of shed antlers evidently represent the large extinct fallow
deer, Cervus brownt, and other bases of antlers are characteristic of
Cervus elaphus. Numerous bovine limb-bones are very variable in
size and proportions, and may belong either to Bos primigenius or to
a Bison. Fragments of limb-bones of a small Rhinoceros are not
specifically determinable. The absence of Hippopotamus is curious,
but remains of this animal have been found not far away in Cockspur
Street and beneath the Admiralty Offices.
In the London district, as in other parts of Southern England, -
there is thus some evidence that the typically warm and typically
cold members of the Pleistocene mammalian fauna were not altogether
contemporaneous.
II.—A Geronoeicat ‘HroRY oF THE OrIcIN oF Man.
ProBaBLe Revarions oF Crimaric CHaNGE TO THE ORIGIN OF THE
Trrrrary Apr-Man. By Professor JosrepH Barrett. The
Scientific Monthly (New York), vol. iv, pp. 16-26, 1917.
AST year (Bull. Geol. Soc. America, vol. xxvii, pp. 387-486)
Professor Barrell pointed out that recurrent periods of semi-arid
conditions might have had much influence on the evolution of
vertebrate animals. As a dry season advanced, rivers would be
reduced in flow, stagnant pools would result, and any fishes which
endured these changed conditions would have to become much
modified. The primitive sharks, for instance, found in the earliest
Paleozoic freshwaters, having no air-bladder, would be driven to the
seas. ‘The freshwater fishes which remained were ganoids and
dipnoans, with an air-bladder efficient for the direct use of air. From
the crossopterygian ganoids, under the stimulus of the semi-aridity
of the Devonian period, there arose the amphibians capable of
existing as land animals; and so on.
The question now arises as to whether a similar climatic change in. |
the Tertiary period, acting on species of large-brained and progressive
authropoid apes, isolated from forest regions, might not cause them
to advance and become adapted for life on plains or die out.
Professor Barrell thinks it would be so, and mentions that at the
close of the Miocene period climatic conditions were such that this
latest evolution may actually have occurred. There were at that
time numerous apes in the warm forests south of the Himalayan
region. As the mountains rose and the temperature was lowered
some of the apes may have been trapped to the north of this area.
As comparatively dry plains took the place of forests, and as the apes
could no longer migrate southwards, those that survived must have
become adapted for living on the ground and acquired carnivorous
instead of frugivorous habits. The Miocene or early Pliocene ape-
man may therefore be more hopefully sought in deposits of the open
and temperate regions of Central Asia than in the alluvial deposits
of the more southern tropical forests.
ib : Th Es ow
Reviews—J. Murdoch—Opaque Minerals. 425
I11.—Guastonpury Laxe- VILLAGE.
‘I\HE second volume of Messrs. Bulleid & Gray’s report on the
Glastonbury Lake-Village is just published. It is most
valuable, and reflects the highest credit on the authors. This
volume contains much matter of geological interest in addition to
the archeology. There are reports on the plants by Clement Reid,
on the bird remains by C. W. Andrews, on the wild and domestic
mammalia by W. B. Dawkins & J. W. Jackson, and on the humans
by W. B. Dawkins. The illustrations are profuse and excellent,
and the report as a whole is as complete an account of such a site as
has yet been made available.
Among the vertebrates the bird Pelecanus crispus is the most
interesting, for although remains have been previously found in the
Fens, Dr. Andrews has examined portions of five individuals and
many fragments from Glastonbury, clearly indicating that the birds
bred in the neighbourhood, and possibly pointing to a source of food
for the inhabitants. The report closes with an exhaustive index,
most wisely provided, which greatly enhances its value.
RAV Tews.
I,—Microscopican DrrERMINATION oF THE Opaque Mrinzrats. By
JosEPpH Murpocu. pp. vii + 165, with 9 figures in the text and
1 coloured plate. New York, John Wiley & Sons, Ine.;
London, Chapman & Hall, Ltd., 1916. Price 9s. 6d. net.
V ] HY the microsccpe, while holding so predominant a position in
the determination of rocks by means of the characters
revealed in a thin slice and in the study of transparent substances
generally, has hitherto been so little used in the study of metals and
alloys and in the identification of opaque substances, is perhaps not
difficult to understand. It is not at first sight by any means obvious
that this instrument is at all suitable for the purpose, and so vast
was the vista opened out by the application of the microscopical
method to petrological work that the equally important field of
research lying fallow in the case of opaque substances for a long
time almost entirely escaped notice. It was, in fact, not till the
discovery of different kinds of hardened steels and the consequent
necessity for determining and explaining their various characteristics
that metallurgists began to pay general attention to the microscopic
study of polished sections. Yet more than half a century has
elapsed since the gifted Sorby, to whom we are likewise indebted
for drawing general attention to the advantage of the microscopic
study of thin slices of rocks, had made use of practically all the
devices in vogue among metallurgists of to-day; while it is only
within the past four or five years that anything like a systematic
study of the opaque minerals has been attempted. Mr. Murdoch’s
book marks the beginning of a new epoch. Previous writers and
workers had confined their attention to some particular mineral
group or some isolated problem. He is the first to make a systematic
study of the opaque minerals, and above all to think out and develop
426 Reviews—Central Scottish Coalfield.
a scheme for identifying them by the characters revealed under the
microscope.
After a full historical account of the work of previous writers—
not a great number—the author carefully describes the comparatively
simple apparatus required for the preparation of suitable polished
sections, and gives a list of the reagents which are used in
microchemical work. ‘The opaque minerals are divided into three
main groups: coloured, white, grey. Difference in hardness as
compared with a steel needle and the behaviour when treated with
certain reagents are made use of for further subdivisions until the
mineral species in question is finally rundown. The white group
is a large one, and for subdivision reliance is placed upon the tint as
compared with the standard white of galena. Mr. Murdoch asserts
that after a little practice the eye can unerringly appreciate such
slight differences as greyish white, pinkish white, bluish white, and
creamy white.
ee eo esc ct AOE a bee ae sor
= ie Alfred N. Leeds, F.G.8. ............ 78
Gigantic Eocene Bird ............ 469 * IV. MISCELLANEOUS.
New Cretaceous Gastropoda ......... 471 | Dove Holes Cave, Buxton... ........ 480
The Silurian Inlier of Usk ......... 472 | The Piltdown Grayels ............... 480
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No. X.—OCTOBER, 1917.
ORIGINAL ARTICLES .~
T.—MorpnHotogican Stupres on THE EcHINoIDEA HoLEcryPorIDA AND
THEIR ALLIES.
By HERBERT L. HAWKINS, M.Sc., F.G.S., Lecturer in Geology, University
College, Reading.
VI. Tue Boccat ARMATURE OF CONULUS ALBOGALERUS, LESKE.
(PLATE XXVIIL.)
1. InrRopucrion.
INCE 1824, when Charles Stokes transmitted to the Geological
Society a drawing of the ‘‘buccal plates” of Conulus, the
question of the existence and characters of the lantern in that genus
has been intermittently, but inconclusively, debated. The course of
this discussion may be briefly outlined here.
Desmoulins, in 1835, was of the opinion that the structures
figured by Stokes were either jaws or teeth, but was uncertain as to
which parts of the lantern-apparatus they might represent. Desor,
in 1842, seems to have regarded these buccal plates as being the
distal ends of the pyramids, being unaware that they were superficial
structures with no inward prolongation. Forbes, in 1850, gave
a figure of the ‘‘jaws and teeth’, and in spite of the peculiar and
improbable nature of these structures as depicted in his figure,
echinologists of such experience as d’Orbigny and Wright accepted
the drawings as representing genuine traces of the lantern. All the
writers above mentioned were convinced that Conulus was a gnatho-
stomatous form, basing their belief chiefly on a very reasonable
analogy with other Echinoids in which the peristome is centrally
placed. It is surprising that there is no record of any serious
attempt at excavation of the interior of a specimen during the first
fifty years of uncertainty. ‘There is little difficulty in making
preparations of the inner surface of the test of an Echinoid from the
_ Upper Chalk, but the genius of a comparative anatomist was needed
to demonstrate that fossils have insides no less than Recent forms.
Lovén and Duncan more or less simultaneously applied their
energies to the elucidation of the detailed internal anatomy of fossil
Echinoids, and, curiously enough, came to diametrically opposite
conclusions as to the perignathic structures of Conulus. lLovén
figured the perignathic girdle, and, while admitting the non-discovery
of jaws, expressed his conviction that such organs were present.
Duncan denied that there was a perignathic girdle in Conulus, at
DECADE VI.—VOL. IV.—NO. X. 28
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434 Herbert L. H annianis! Seer on the Echinoidea.
least of a functional kind, and definitely stated that jaws could not
have existed in the genus. He ridiculed (with some justice) the
figure of the teeth given by Forbes, ascribing them to grooves made
in the infilling chalk of the specimen by the use of a graving tool.
As a result of his denial of the existence of jaw-structures, he
detached Conulus from its hitherto unassailed position among the
Holectypoida (Echinoconide) and relegated it to the group containing
Pyrina and Echinonéus.
That Duncan was wrong in denying the presence of a perignathic
girdle in Conulus is patent to all who care to develop the interior of
the adoral surface of any species of the genus; it is difficult to
understand how so reliable an observer could have overlooked such
an obvious structure, and have succeeded in blinding the perception
of another worker of the standing of W. P. Sladen. ‘Thus his chief
argument against the occurrence of jaws in the genus is based upon
inaccurate observation, and, indeed, recoils. Since there ¢s a peri-
enathic girdle, and the main purpose of such a development is for the
attachment of the muscles that work the jaws, the presence of the
latter structures must logically be inferred until disproved—a difficult
or impossible proposition. ‘The two sole bases for such a negative
argument are, firstly, the non-discovery of the ossicles in question,
and secondly, the obliquely elliptical outline of the peristome.
The transfer of Conulus to the Echinonéide by Duncan may or
may not be justified, but an entirely different complexion was put
upon such a change by the discovery by A. Agassiz in 1909, of
a fully developed lantern in a post-larval Hchinonéus. Although
this vestigial lantern is resorbed before the mouth becomes functional,
its complete development at such a relatively late stage in ontogeny
is a clear indication that the recent Echinonéide have descended
from ancestors which were gnathostomatous at no very remote
period. ‘The post-larval lantern of Hehinonéus is associated with
a simple, but defined, perignathic girdle. This girdle is com-
pletely resorbed at the same stage of ontogeny as the lantern.
On the inevitable hypothesis that Hehinonéus and Conulus are nearly,
if not directly, related, it would be expected that the latter genus
should show a longer persistence of the jaw-apparatus, but that, as
its ontogeny progressed, the structures should steadily degenerate.
The last anticipation, so far from being justified by the known facts,
is directly negatived by them. The largest specimen of Conulus
albogalerus in which I have studied the perignathic girdle shows that
structure developed into far greater complexity and perfection of
detail than it presents in smaller examples. Hence it is reasonable
to argue that, since the loss of the lantern in Hehinonéus coincides in
time with the complete destruction of the perignathic girdle, the
retention and specialization of the girdle in gerontic specimens of
Conulus indicates that the lantern was persistent throughout life.
In 1911 I was able to describe and figure actual teeth, with
characters and proportions little different from those of Dzscoides, in
a specimen of C. subrodundus. ‘The specimen is fully adult, but it is
strangely anomalous to find such relatively small elements as the
teeth when there is no trace of the usually far more massive
Herbert L. Hawkins—Studies on the Echinoidea. 485
pyramids. However, where there are teeth there must surely be
jaws of some kind, so that it must be allowed that the species of
Conulus were gnathostomatous at least as late as the period of the
Middle Chalk.
The case is very different as regards C. albogalerus, the Upper
Chalk species. The interior structures are readily accessible owing
to the commonly soft nature of the matrix, but hitherto no indication
has been found of any buccal armature save the perignathic girdle
and the “‘ buccal plates”. In the paper referred to above I accepted
the suggestion that the buccal plates might be curiously modified
relics of the pyramids, and that the species was edentulous. One of
the main purposes of this paper is to express an absolute and complete
recantation of this suggestion. The arguments in the next section
will, I think, suffice to account for, if not to explain, the peculiar
nature of the buccal plates, and the latter description of the presumed
fragments of true pyramids recently discovered will afford insight
into the reason for their habitual non-preservation in a recognizable
condition.
2. Tur Buccat Puates.
One of the most striking features of the Echinoid fauna of the
Upper Cretaceous is the massiveness of the test-fabric. Such a genus
as Stereocidaris illustrates this point very clearly; but it is most
obvious in the Irregular Hchinoids. A comparison between
- Echinocorys and the nearly allied recent genus Urechinus shows
an extraordinary contrast in the thickness of the coronal plates.
The ‘‘ Heart-Urchins”’ of the present fauna are, for the most part,
constructed of exceedingly delicate fabric, the test often being as
thin as tissue-paper. But Meraster and Hemiaster, the Cretaceous
representatives of the ‘‘Heart-Urchins’”’, have tests of almost
unwieldy thickness.
As a generalrule, the Kchinoids of the present day may be divided
into two sections; those whose habitat is exposed, and those which
live buried in sand or ooze. The former group comprises most of the
Regular Kchinoids, and may be illustrated, in an extreme case, by
such a form as Heterocentrotus, in which the coronal plates may be
as much as a quarter of an inch in thickness. Another type of
‘‘exposed’”’ KEchinoid is the ‘‘Sand-dollar”, in which, even when
the test is not very thick (as it is in Clypeaster), the whole fabric is
supported by pillars and buttresses within. The latter group may
be represented by Hchinocardium, where the test is exceedingly thin
and fragile. The difference in test-thickness is obviously, from one
point of view, a mechanical adaptation to the requirements of the
habitat. The strong test that will successfully resist the pounding
of the waves can be almost dispensed with in the shelter of a burrow.
There is, however, small ground for believing that the surroundings
of such a genus as Micraster were in any sense tempestuous; the
reverse is more probable. So that the great thickness of the test in
the Chalk Echinoids must be due to some other cause. Indeed, it
would seem that they underwent excessive calcification quite
independent of their mechanical needs; and this thickening was
436 Herbert L. Hawkins—Studies on the Echinoidea.
therefore likely to affect other stereom-structures besides the actual
corona. The buccal-membrane plates of Echinocorys, as Lambert and
I have described them, are far more robust than those of similarly
sized Spatangoids of the present day, although far inferior in
thickness to the coronal plates. The periproctal plates of Discozdes
are equally strong.’
In a specimen of Conulus albogalerus, the interior of which is
almost filled with flint, there are numerous thick, granular plates in
the mealy chalk within the periproct. They are like the buccal
plates in every feature except that of shape, and I have not the
slightest hesitation in identifying them as the plates of the periproct-
membrane. Since the periproctal plates are so enormously thickened
in this species, it is only to be expected that the peristomial ones
should be in a similar condition. There is, therefore, good reason
for believing that the buccal plates of Conulus are merely the plates
of the buccal membrane, and that their strange proportions are but
an advanced expression of the Upper Cretaceous ‘‘ mode”’.
[Note inserted 1n proof, September 14, 1917. — The preceding
paragraphs were written in July of this year. The Editor has
kindly drawn my attention to two recent papers in this Magazine
which include references to the phenomenon of ‘‘ super-calcification ”’
in Cretaceous forms. One, by W. D. Lang, deals with Polyzoa,
and the other, by C. T. Trechmann, is concerned with Mollusca.
The Editor has also reminded me of the extraordinary superfluity
of shell-substance developed in the Rudistacea in the same period.
In some cases it is easy and probably correct to ascribe the secretion
of apparently unnecessary mineral matter to phylogerontic over-
specialization (e.g. Parkinsonia dorsefensis from the Bathonian, and
Clavella longeva from the Bartonian). But in the case of the
‘‘ Heart-Urchins” above mentioned, such an explanation seems
impossible. Hemiaster, Mieraster, and Kpiaster represent the pro-
gressive pioneers of the Spatangina, not degenerate and superannuated
relics; and a quality that affects a large proportion of a fauna,
irrespective of the phylum or phylogenetic phase of the individuals,
must surely have originated from some more comprehensive and
fundamental cause. However, this is not the place for a discussion
of the problem. |
If the foregoing interpretation of the buccal plates is correct, an im-
portant corollary follows. Lovén showed that the young Hchinocardium
_ flavescens, where the outline of the peristome is roughly circular, has
ten elliptical plates on the buccal membrane, arranged in a complete
cycle near the circumference of the aperture. In 1912 I indicated
the close correspondence in most characters between the early
ontogenetic stage of the buccal plating in Hehinocardium and the
‘“bueeal plates” of Conulus; but hesitated to correlate the two sets
? The same remark applies to the periproctal plates described by F. J. North
(Ann. Mag. Nat. Hist., December, 1915). His specimen is obviously a species
of that Upper Chalk Caratomid genus variously called Hcehinoconus (Desor, fid.
Lambert), Pironaster (Schlueter), or Conuwlopsis (Hawkins). Anyhow, the
horizon from which it was collected, and all the particulars published about it,
show clearly that it is not a Discoides.
ie
ae
Herbert L. Hawkins—Studies on the Echinoidea. 437
of structures owing to the ‘‘ massive character of the latter ossicles’’.
If the foregoing argument is sound, this difficulty disappears. Hence
it is with confidence, bordering on conviction, that I now express
the opinion that the ‘‘ buccal plates” of Conulus albogalerus represent
the Cretaceous phase of the plating of the buccal membrane which
is recapitulated during ontogeny in the earliest post-larval stage of
Echinocardium flavescens. This does not necessarily imply a direct
phyletic sequence between Conulus and the ‘‘ Heart-Urchins”’; it is
rather a fresh illustration of morphic parallelism independent of
actual phylogeny. But it entirely destroys the arguments put forward
by me in 1911 (Geort. Mae., p. 73), and cancels the hypothetical
diagram there given (PI. III, Fig. 8).
3. THe Perienatuic GirpLe. (Pl XXVIII, Figs. 1-3.)
(a) The Angle of Inclination. (Pl. XXVIII, Figs. 2, 3.)
The elements of the girdle in the Holectypoida, when viewed from
within, always show a slope outwards from the peristome, thus
contrasting with those of the Regular Echinoids, which are com-
paratively vertical in direction. In Conulus albogalerus, as in
Discoides (see Part V of this series), the greater part of the girdle
reclines against, or is bevelled off from, the proximally thickened
interambulacra. There are thus two roughly circular rings whose
diameters may be measured: the actual peristome margin and the
upper limits of the girdle. In a young specimen of C. albogalerus.
(Fig. 3), where the diameter of the adoral surface is about 25mm.,
the former diameter is c. 4mm. and the latter ¢. 65mm. In
a gerontic specimen (Fig. 2), with an adoral diameter of about 48 mm.,
the corresponding measurements are 5mm. and 9 mm. respectively.
Reducing these measurements to a proportionate scale, we arrive at
the following result :—
Diam. of Diam. of
; peristome. top of girdle.
Young specimen F ; 1 1-62
Old specimen . ; : 1 1:80
Specimens of intermediate sizes give proportionate results between
these two extremes. Thus the obliquity of the girdle appears to
increase with age. However, the vastly greater thickness of the
interambulacra in the old specimen automatically increases the
‘‘ splay” of the bevelling, and in reality the obliquity of the girdle
is considerably less in the gerontic than in the small specimen. The
approximate angles between the girdle and the plane of the adoral
surface in the two examples are as follows :—
Young specimen : : : é : ile
Old specimen . , ; ; , j 25°
The actual inclination of the girdle in the fully grown example is
thus more than twice as steep as that in the young one. ‘This
result has been checked by the measurement of the angles in
twenty-eight specimens of intermediate size. It is somewhat
surprising to find a decrease in obliquity during the growth of
438 Herbert L. Hawkins—Studies on the Echinoidea.
Conulus—the reverse would have been anticipated. From Plesve-
chinus onwards the record of the perignathic girdle is one of eyer-
increasing obliquity, and in the Clypeastroids the angle between the
plane of the adoral surface and a line joining the peristome-margin
to the top of the girdle is very acute. The reversal of the trend of
evolution in Conulus would thus seem to indicate that there is no
direct phyletic course from the Holectypoida to the Clypeastroida by
that route ; a conclusion that is supported by most other morphological
indications. But it is a reversion towards the ‘ Regular’”’ character,
and as such might be held to imply that the jaws of Conulus
“improved” in quality during ontogeny. On the other hand, it
- seems equally logical to suggest that the continued thickening of
the proximal parts of the interambulacra prevailed over the failing
girdle, so that its increased: slope is an expression of its waning
functional importance. On general grounds, I incline to accept the
latter alternative as the probable explanation of this anomalous
feature.
(b) Zhe Structure of the Gudle. (P|. XXVIII, Figs. 1 and 2, )
The general characters of the girdle of C. albogalerus are well
known, and little in the way of description needs to be added to the
account given by Lovén in Zchinologica. The chief problem is
concerned with the interpretation of the observed structures. For
this purpose I have chosen the very large specimen to which
reference has been made in the preceding section, since this shows
all the details of the girdle with an exaggerated clearness. The
peristome is elliptical, with its long axis in the direction 3, I.
The general plan of the girdle strikingly resembles that of a Tudor
rose. ‘The five ‘‘ petals” rise sharply from the peristome-margin in
concave and embayedescarpments. Outside them the interambulacra
rise to a slightly greater height, and then gently slope down towards
the ambitus. ‘he ‘ petals” are separated from one another by the
deep and narrow sulci of the ambulacra. The lateral margins of
a ‘‘petal”’ consist of slender, projecting processes, based upon the
bordering ambulacra, and visibly sutured to the main structure.
Each process culminates distally in an almost spherical and glossy
knob, which projects upwards and inwards beyond the general level
of its surroundings. The ‘‘ petal” itself may ‘be considered to consist
of three parts. “There is a central prominence on the peristome
border, rising sharply and culminating in a bevelled erest. Above |
this the chief part of the ‘‘ petal’? rises in a deeply concave slope,
bisected by a median carina, which, though prominent, is also
concave in the upward direction. At the top of the structure,
overhanging the bays and carina of the main surface, is an almost
flat area which slopes very gently towards the peristome, and has an
imperfectly defined rim distally. (This platform is practically non-
existent in smaller examples.) Beyond the platform the inter-
ambulacrum rises a little above the sulcate suture which bounds the
girdle, and then falls away gently towards the ambitus. The only
sutures that I have been able to detect with certainty are (1) those
between the bordering processes and the ‘“‘ petal”’, (2) a crescentic
Piste (? Rv lice a eKIT
Herbert L. Hawkins—Studies on the Hchinoidea. 439
boundary suture between the platform and the normal inter-
ambulacrum, and (3) an interradial suture bisecting the carina. In
addition, there appears to be a suture between the prominence and
the carina, but it is by no means clear, although the junction between
these two parts of the structure is very sharply defined.
The only additional ingredient of the girdle is the narrow, but
proximally striking, carina which occupies the line of the perradial
suture. ‘he bulbous proximal end of this carina extends inwards
beyond the normal circumference of the peristome. It is presumably
developed for the stiffening of the thin coronal plates of the
ambulacrum, which would otherwise seriously weaken the cohesion
of the adoral parts of the test; but it may possess a further function,
to which reference will be made later. The carina covers and quite
obliterates the perradial suture.
(c) The Homology and Function of the Structures.
A comparison of the elements of the girdle of Conulus with those
of Discoides (see Part V of this series) reveals an essential similarity.
The processes are quite obvious. ‘he central interradial prominence
on the peristome-border is clearly the ‘‘ true ridge”, while the
remainder of the interradial structure represents the ‘‘false ridge”’.-
Assuming the existence of a lantern, the retractors will have been
attached to the upper parts of the processes, and the protractors to
the true ridges. The false ridges, by analogy with those of Discordes,
will have served as a rest or slide for the inclined pyramids. The
only serious difference in the girdle-structure between Duscovdes and
Conulus is found in the false ridges. In Discoides each false ridge
is practically an inclined plane, with a very faint median concavity.
In Conulus it has a concave surface, with a median carina, deeply
excavate sides, and an overhanging summit. I believe that these
three features are all to be associated with the curious nature of the
buccal plates. The pyramids of the lantern would rest upon the
_ true ridges and the gently inclined summits of the false ridges, and
so would leave considerable spaces between themselves and the deep
hollows, and even the carinz, of the slopes of the false ridges.
When the mouth was opened the massive buccal plates would
inevitably need to be shifted, and it is hard to imagine more likely
or suitable places for them than the deep slots in the false ridges.
The median carina and the projecting edges of the processes would
ensure their sliding in the right direction (so as to avoid confusion
with the protractor muscles), and the proximal bulb of the perradial
carina might have served to start them on their proper course when
retracted. Thus the view put forward by me in 1911 as to the
movement and disposal of the buccal plates still holds good, although
I now disbelieve in the homology between those plates and the
lantern-pyramids.
If the lantern was of a ‘‘ flaring’”’ nature (as would be probable in
view of its character in Discovdes and the Clypeastroida), it must
perforce have come very near to, if not into contact with, the upper
part of the perignathic girdle. Whether it articulated with the
glossy knobs at the summits of the processes is a matter of doubt,
440 Herbert L. Hawkins—Studies on the Echinoidea.
but such an arrangement would be in keeping with the Clypeastroid
character. But it might well have reclined upon the “ platform ”
of the false ridge, bridging across the concavity between that and the
peristome margin, and leaving space for the buccal plates to be
retracted behind it. Such speculations are, however, of little value
until more is known of the structure of the pyramids.
4, Tue Lantern.
When the chalk infilling of a test of Conulus albogalerus is brushed
down, it proves to be surprisingly full of small, usually fragmentary,
pieces of calcite. These are naturally often portions of Foraminifera,
Polyzoa, or Pelecypod prisms that have drifted in with the ooze.
But the fact remains that these fragments seem more thickly
scattered through the internal than the external matrices. I have
destroyed several hundreds of specimens of C. albogalerus in my
hitherto vain endeavours to find the jaws; and in one example only,
from the top of the JL. coranguinum zone near Kingsclere, have
any reasonably satisfactory portions been observed. Their nature
explains the peristent way in which they elude recognition. They
are small, and so delicate in texture that they are translucent, and
the friction due to even a soft tooth-brush readily shatters them, if
applied at random. In the specimen here noted the chalk within
the test was almost powdery in consistency, and was removed with
a camel’s-hair brush. Two or free fragments, which seem to
represent pyramids, were extracted, but they are so broken and
difficult to orientate that I prefer to postpone full description of
them in the hope of procuring better specimens.
I have selected one of the fragments (3 mm. long and about 1 mm.
broad) as indicative of the general characters of these interesting
ossicles. It is shown on Pl. XXVIII, Figs. 4, a, b, ¢, from three
points of view, a, 6, and ¢. How far its outlines are natural or are
the product of fracture is difficult to determine. The fragment is
roughly triangular, and excessively thin. The top and bottom are
both broken. One side is gently crescentic in shape, and the other
almost straight. I believe that the curved side is a natural margin,
but whether the straight edge is natural or the result of cleavage
I cannot determine. One surface (a) shows a carina passing longi-
tudinally near to the straight margin at the broader end of the
surface, and separating two ovoid excavations. Towards the narrower
end the ossicle is thicker, the carina less prominent, and one side of
the surface is gently bevelled. A comparison of this figure with that
of the alveolar view of a maxilla of Discoides (Grou. Mae., 1909,
Pl. VI, Fig. 5) shows an almost startling resemblance. If the
straight edge of the Conulus-ossicle is taken to be a cleavage line,
cutting the maxilla vertically and removing the inward extension of
the inter-pyramidal joint-face, the likeness between the figures is
complete in all save proportions. The two figures are supposed to
be similarly orientated.
Fig. 6 is a view of the (?)cleavage margin of the ossicle. It
shows the extreme tenuity of the structure at the broad, excavate
end, and its superior massiveness at the narrow end.
Pratt XXVIII.
Grou. Maa., 1917.
WM Sa
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PERIGNATHIC GIRDLE OF CONULUS ALBOGALERUS, Lesxs.
H. L. H. del.
Herbert L. Hawkins—Studies on the Echinoidea. 441
Fig. ¢ shows the opposite side of the ossicle to that drawn in
Fig. a. It is not quite parallel to that side, but makes a very acute
angle with it. Save fora slight median sulcus, increasing in depth
towards the narrow end, it is plain. It is very suggestive of the
external surface of the maxilla of Discozdes (loc. cit., Fig. 2), but only
if the straight edge of the ossicle is regarded as the symphysial
margin instead of a cleavage line.
It is difficult to imagine that this fragment can be other than
a part of a maxilla, and still more difficult to doubt that it belonged
to the specimen in which it was found. Other fragments include one
which suggests the existence of alar expansions lke those of the
Clypeastroida (with a similarly reticulate character), and another
that is presumably part of a stirodont tooth. For the reason stated
above I prefer to leave all detailed discussion of these structures to
the future.. The specimen figured is sufficient to indicate the grounds
for my belief that the lantern of C. albogalerus has been found at last.
5. SUMMARY.
The perignathic girdle of Conulus albogalerus 1s shown to resemble
closely that of Dvuscoides, with modifications due to the greater
degree of thickening of the interradial coronal plates and to the
massive character of the buccal plates. These are considered to be
the true plates of the buccal membrane, and to have been capable of
retraction into the deep sockets of the false ridges of the girdle.
The existence of a lantern is inferred as a result of arguments based
upon the known characters of the girdle and upon analogy with
related types. Certain imperfect ossicles found within the test of
a small specimen are considered to represent portions of the lantern ;
and one, here figured, seems clearly to be a fragmentary maxilla
similar in all essentials to that of Discovdes, but differing in shape and
proportions. Further discussion of the presumed lantern is deferred
until better material is acquired.
The next paper in this series will deal with the perignathic
structures of the Holectypoida as a whole, with a discussion of the
internal characters of the peristomes of some early Spatangoida.
Fig. EXPLANATION OF PLATE XXYIII.
1. Perignathic girdle of a gerontic specimen of C. albogalerus. xc. 6. All
sutures except those at the sides of the processes are omitted. There is
a suture down the middle of each false ridge, but the median lines on the
true ridges represent the crests of carine, not sutures. The outlines of
the various parts are slightly emphasized, but otherwise the figure is not
diagrammatic.
2. Section along the axis 4, II, of the same specimen. X c. 6.
3. Section along the same axis of a smaller specimen. x syenite —> shonkinite —> perknite
anorthosite —> gabbro —> (picrite) —> pyroxenite, etc.
alaskite —> granite —>
To make such a distinction quantitative, 1t would accord fairly with
existing practice if we fixed the boundaries at 3, 50, and 97 per
cent of heavy minerals. In the oversaturated division it is obvious
that the melanic end-member of each family would be a quartz-
perknite. In the S and U divisions it would be a pyroxenite or
hornblendite. In the u and W divisions the corresponding end-
member would be a peridotite or cromaltite.? All the varietal names
required for the more minute description of these are already in
existence. For the leucocratic end-members too it will rarely be
necessary to find new names, since nearly all cases are already
covered by such names as orthoclasite, albitite, oligoclasite, anor-
thosite. It is mainly for the third group, containing from 50 to 97
per cent of heavy minerals, that new names analogous to shonkinite
will be required. Owing to the similarity of the end products, the
total number of distinct groups will not be 8 x 4, but practically
about 20 in each division. The four groups in each family may be
distinguished by the letters L, 1, m, and M where suitable names are
not at present in existence.
5. As regards crystallinity, I have a decided preference for the
two groups of Zirkel (and Iddings) as opposed to the three groups of
Rosenbusch (and Holmes). As everybody knows, there is no special
‘set of characters which one can postulate of a so-called dyke rock—
not even that it occurs in a dyke. Some dyke rocks have all the
characters of plutonics, others all those of lavas. There are in fact
only two sets of cooling conditions which produce really significant
differences in the characters of the rocks formed under them; these
conditions are slow cooling with a sufficiency of fluxes and rapid
cooling with diminished content of fluxes: that is, plutonic and
effusive conditions, giving rise to phanerocrystalline and aphanitic
rocks respectively. If itis desired to express the actual manner of
occurrence of a rock mass, it can be done by means of a prefix
attached to the name, as dyke-granite, dyke-rhyolite, and so on.
A tinguaite I would describe as a dyke-phonolite, a grorudite as
a dyke-ekerite or microekerite, a vogesite as a dyke-shonkinite,
a hedrumite as a micronordmarkite, etc. In this way a great
number of superfluous names might be eliminated and others reduced
in value from group names to mere varietal names.
1 Journ. Geol., 1916, p. 400.
2 Melanite-pyroxenite: Trans. Geol. Soc. Edin., 1910, p. 376
alah
‘
468 Professor S. J. Shand—A System of Petrography.
The names of the aphanitic subfamilies in this system ought of
course to be drawn from existing names of lavas, just as those of the
phanerocrystalline rocks have been derived from existing names of
plutonic rocks, and the same set of prefixes and suffixes may be used
to signify the degree of saturation, thus: andesite, subandesite ;
latite, sublatite, latoid, sublatoid; and soon. A certain amount of
redefinition of names will be necessitated, and a number of new
names will be required. It is not proposed to coin these in advance:
it is better that the supply should wait upon the demand. In the
meantime it is always possible to describe any rock by means of its
co-ordinates in the system, thus: 03 L2; 8711; u M1, ete.
6. With five divisions, about twenty effective groups in each
division, and two subgroups within each group, we have already
distributed all known igneous rocks into about 200 compartments.
Within each of these compartments there is still room for consider-
able variation as regards both the minerals themselves and their
proportions. A further use of the colour-ratio prefixes, ls to ls and
ms to ms, makes it possible to describe variations in quantity of light
and dark minerals. In the same way we may express different
degrees of oversaturation by means of prefixes, O,, Os, Os, ete. It
will still be necessary to discriminate between different mineral
associations. Compartment U2, for example, holds both leucite-
albite rocks and nepheline-orthoclase rocks, and these will certainly
require different ‘‘ specific’? names. Again, inthe u division we find .
rocks with unsaturated magnesium and others with unsaturated
calcium; and in W the melilite rocks (for melilite holds soda as well
as lime and magnesia) form a distinct facies. It is therefore to be
expected that from 300 to 500 “specific” names will be required in
all. These should be supplied, of course, partly by the readjustment
of existing names and partly by the coining of new ones as the need
arises. Still further subdivision is possible on a basis of texture;
but it is the writer’s opinion that differences of texture, other than
the one fundamental difference already considered, should be expressed
by prefixes or descriptive adjectives, not by the coining of new
names. .
It will be noticed that no place has been found in this system for
the order of crystallization. This is one respect in which it is to be
hoped that the system may in future suffer modification. In the
meantime the discrepancies between theory and observation are so
great that it would only be misleading to give to this factor any place
in systematic petrography.
In conclusion, let me say that I do not claim for the system
elaborated above that it is either a ‘‘ natural classification”’ or a final
one, or that it will enable one to dispense with chemical analysis.
It is nothing more than a system of indexing, based as far as possible
on significant mineralogical data treated quantitatively. It lays down
lines along which the naming of rocks should proceed, and fixes
sharp boundaries which no rock-name should transgress if it is to be
more than a mere sack-name. The coining of unacceptable new
names is largely avoided by the use of simple prefixes and suffixes,
and where existing names have been used their connotation has been
ai.
Reviews—A Gigantic Eocene Bird. 469
narrowed but not radically altered. A thorough reformation of
petrographic system is urgently called for, and it is felt that the
scheme now presented affords a great increase of precision and
significance at the cost of the smallest possible rearrangement of
ideas. I do not wish to compare this system more closely than
I have already done with those of Iddings and Holmes, but it is my
hope that English-speaking petrologists will awaken to the necessity
of themselves testing these and any other propositions that may be
forthcoming, and of coming to some agreement regarding the exact
meaning of the terms they use. There is room for wide differences
of opinion, but ‘‘ the dust of controversy—what is it but the falsehood
flying off?”
REV Lews.-
i:
THe Sxereron or Drarryué, A Gicantic Brrp FRom THE Lower
Kocene oF Wyomine. By W. D. Martraew and Watrer
GranceR. Bull. Amer. Mus. Nat. Hist., vol. xxxvu, pp. 307-26,
pls. xx-xxxill, 1917.
A Gicantic Eocene Birp.
O long ago as 1874 Professor Cope gave an account of some
fragmentary remains of a very large bird from the Lower
Eocene of New Mexico, referring it to a new genus and species
under the name Diatryma gigantea. Since that time a few additional
fragments have been described by various writers, but it was not
until last year that the discovery of the greater part of a skeleton in
the Bighorn basin of Wyoming made it possible to get any clear idea
of the structure of this remarkable creature. This specimen has
now been described and figured and its affinities discussed by
Messrs. Matthew and Granger in the memoir referred to above.
Diatryma is now shown to have been a ground bird of great size,
standing some 7 feet in height and possessing a relatively very
large head and vestigial wings. It was not a ‘‘ Ratite”’ in the usual
sense of the word, but like Phororhacos, to which it has much
superficial resemblance, was a highly modified Carinate, most of its
peculiarities resulting from its loss of the power of flight. The
skull, as in Phororhacos, is of extraordinary size, measuring about
17 inches in length and being largely made up of a great compressed
beak 9 inches long by 63 high. ‘The tip of the beak is not decurved
as in Phororhacos, and the small sharply defined nostrils are situated
rather nearer the ventral than the dorsal border of the beak and some
2 inches in front of the orbit, which seems to have been incomplete
below. The supra-temporal fenestra is closed below by the union of
the postorbital with the squamosal. The quadrate has a single
transversely expanded head with two imperfectly separated facets for
articulation with the squamosal. The jugal is stout and its anterior
end unites with the maxilla much above its ventral border. The
vertebree are short but massive, especially in the cervical region.
The ribs are wide and thin, with little or no trace of uncinate
OO ee Ape eae
PMU col
, +
-
470 Reviews—A Gigantic Hocene Bird.
processes. The sternum is unknown. ‘The shoulder-girdle is more
like that of a Ratite than that of a normal Carinate, the coracoid and
scapula being almost in the same straight line instead of making
a sharp angle with one another; the coracoid is short and: broad.
The humerus has undergone great reduction and is in much the same
condition as in the Cassowaries; the structure of the rest of the wing
is unknown. The pelvis is remarkably short in front of the ace-
tabulum, but is long and wide posteriorly ; the ilium and ischium are
co-ossified, and the pubis, which is in contact with the ischium, unites
with it for a short distance. This pelvis is not at all like that of
a Ratite bird, but is said to resemble that of Cariama. The,bones
of the hind limb are completely adapted for a pedestrian gait, and
probably the adaptive characters have completely masked any that
might throw light on the relationship to less specialized forms.
The authors discuss the possible relationship of Diatryma to other
S
birds. They dismiss, probably quite rightly, the idea of any near’
affinity with the later Phororhacos, but at the same time suggest
a relationship with Carzama, apparently on rather slender grounés.
They conclude that “probably Phororhacos is a derivatite of some
extinct Kocene type of normal adaptation allied to the Eocene
ancestors of Carvama, while Diatryma would be a derivative of
normal Cretaceous Euornithes, allied perhaps more closely to the
ancestral line of Carvama’’.
From inspection of the photographs alone, it is perhaps rash to
offer any suggestions, but several points in the structure of the skull
seem worthy of notice. From the figure it appears that there was
probably a well-developed fronto-nasal hinge such as is especially
well developed in the Parrots; the supposition that such a joint
existed seems to be supported by the condylar form of articulation
of the pterygoid and palatine. Again, the closing of the supra-
temporal fossa below occurs in many Parrots, and small, sharply
defined narial openings also occur in some members of that group, as
the authors point out. The form of the jugal and the manner of its
union with the maxilla is also parrot-like. On the other hand, in
Parrots the orbit is usually closed below, while in Diatryma it
remains open, atleast apparently so. A simple-headed quadrate, very
similar to that of Diatryma, occurs in Stringops, which is regarded
by Firbringer! as the most primitive type of Parrot, although its
primitive characters are obscured by later specializations, while the
group, as a whole, is considered by the same writer as a very ancient
one. Of course, the form of the bones of the hind limb of Diatryma
appears to be against any relationship with the Parrots, in which the
hind limb has become modified to form a highly specialized climbing
and grasping organ, but possibly in the early members of this group
these characters had not been acquired, and Diatryma may have
originated from some such unspecialized form. ‘The earliest fossil
Parrot which is definitely known is Pstttacus verreauxti, Milne-
Edwards, from the Lower Miocene of the Allier, France; in this
the climbing type of hind limb was already fully developed.
* Journal fiir Ornithologie, 1889, p. 236 ; also Untersuchungen zwr Morpho-
logie und Systematik der Vogel, p. 1285 et seqq.
Reviews—New Cretaceous Gastropoda. 471
Marshall! states that remains of Parrots occur in the Eocene of
Wyoming, but I have been unable to find any warrant for this
statement.
CHas. W. ANDREWS.
IJ.—Nerw Creracrous Gasrropopa. By Bruce Wank.
A NOTABLE contribution to the paleontology of the Cretaceous
Mollusca has recently been published in the Proceedings of the
Academy of Natural Sciences of Philadelphia, vol. lxviii, pt. iii, for
1916-17 (pp. 455-71, pls. xxili-iv), under the title of ‘‘ New
Genera and Species of Gastropoda from the Upper Cretaceous’’, by
Bruce Wade. The paper is descriptive of a number of elegant shells
in a remarkable state of preservation, some having colour as though
freshly taken from the sea. The material was collected at Coon
Creek, in the north-eastern part of the Nairy County, in west-central
Tennessee, from an horizon in the lower part of the Ripley formation.
With such excellent material as a basis, several new generic types
have been described, and the results will be helpful to those who are
familiar with similar shells from other areas, and cognizant therefore
of the necessity for the establishment of new divisions. Seven
families are represented among the forms described, and there are
nine new genera and eleven new species. J/ataxa elegans is the type
of a new genus of the Cancellariide; and among the points of
difference from Cancellarva are the development of a canal, the lack
of conspicuous cancellate sculpture, and a less acuminate spire.
Mataxa includes Stoliczka’s Narona eximia, from the Cretaceous of
Southern India, and is probably near the recent sub-genus Massyla.
To the Volutide are assigned two new genera, Zectaplica and Drilluta.
Tectaplica is considered as one of the most primitive of the Volutes,
and as ancestrally related to Volutilithes, from which it differs in
haying a shorter spire, with flat sides not interrupted by pronounced
‘ shoulders. TZectaplica simplica is the genotype. The new name
Drilluta is a contraction of the names Drillia and Voluta, and the
genus includes a group of Volutes that have been variously described
under these names and also under Fasciolaria and Fusus. The absence
of a posterior siphonal notch and the presence of columella plaits
distinguish this new genus from Drillia, while a lower spire and
numerous transverse folds can be noted as points of difference from
the typical Voluta. Drilluta is separated into two well-defined
groups: section A (type, D. communis, sp. nov.) and section B (type,
D. mayor, sp.nov.). The Fuside are represented by a new sub-genus
Anomalofusus, and Ornopsis, gen. nov. The new sub-genus resembles
Phos, but is much more slender, and it differs from Fusus in its
shorter canal and its thickened and notched outer lip. Fusus (Anomalo-
fusus) substriatus is the type. Ornopsis glenni is the type of a genus
‘that bears resemblance to Zatirus in general outline, and to some of
the Buccinide in its close compact spire. Hydrotribulus (type,
H. nodosus, sp. nov.) is a new genus, assigned to the Buccinide,
1 Zoologische Vortrdge, ‘‘ Die Papagaien,” p. 45, Leipzig, 1889.
472 Reviews—C. I. Gardiner—Silurian of Usk.
characterized by a low spiral angle, strong cancellate sculpture,
a much inflated body, and by a much excavated and reflected inner
lip, which conceals an umbilicus. It has a general resemblance tof”
Pyrifusus, and includes a species from the Senonian of Aachen,
referred by Miiller to the genus Rapa, and by Holzapfel to Tudiela.
Referred to the Euomphalide is a shell that has a flattened spire,
a deep wide umbilicus, of which the outer margin is conspicuously
produced, and an angular peripheral margin. It shows points of
resemblance and difference both with Discohelix and Straparollus,
and a new genus, Hippocampoides (type, H. serratus, sp. nov.), is
instituted for it. Representatives of the Turbinide and Delphinulide
are also described. A new genus, Schizobasis, is assigned to the
former, and the genus Urceolabrum, also new, to the latter. Schizobasis
depressa is the type of a turbiniform genus that is characterized by
a short well-defined canal, a feature not found in any other members
of the Turbinidz. A conspicuous circular reinforced aperture, a deep
umbilicus, and an elevated cancellate spire are characters that typify
Urceolabrum tuberculatum, gen. et sp. nov., the genotype of a well-
defined group of forms new to the Delphinulide. To this new genus
is also referred a form described by Miller from the Aachen Beds as
Scalarta, and afterwards by Holzapfel as Lvotva.
Il1.—Tue Sitvrraw Intrer or Usx. By C. I. Garpinen, M.A.,
F.G.S.; with a Paleontological Appendix, by F. R. C. Cowrrr
Rerep, M.A., D.Se., F.G.S. Proceedings of the Cotteswold
Naturalists Field Club, vol. xix, pp. 129-170, pls. vil and vill
and Geological Map.
‘J\HE general structure of the inlier consists of two anticlines with
a N.N.E.-S.S.W. trend separated from each other by a fault,
having the same general direction. The western, or Coed-y-paen,
anticline is more important than the eastern, or Llangibby, anticline
and brings the Wenlock Shale (the lowest exposed rock) to the
surface over a large area. The Wenlock Limestone comes in at
a somewhat indeterminate horizon, which is probably not quite the
summit of the Wenlock Shale, and over this the Ludlow rocks lie
conformably. There is no typical Downtonian, but the basement
bed of the Old Red Sandstone overlies the Ludlow with very little
discordance in dip. The rocks of the Llangibby anticline as seen at
the surface belong almost entirely to the Ludlow series, and only at
one place is the Wenlock Limestone exposed ; however, three small
inliers of Old Red Sandstone are brought in by minor synclines.
Only on the south and west of the Coed-y-paen anticline does
the Old Red Sandstone overlie the Ludlow rocks directly; on all
other sides wherever it can be seen the boundary of the inlier is
a faulted one. The chief of these faults, like that dividing the two
anticlines, have a N.N.E-S.S.W. direction; but there is also another -
series of faults in a more or less H.-W. direction which are later than
the first-named series. These systems of faults must be referred to
the Pennine and Armorican foldings respectively, as they affect the
Old Red Sandstone as well as the Silurian.
Reviews—P. Termier—The Evidence for Atlantis. 478
The rocks in this area present quite normal characters; the
Wenlock Shale is 850 feet thick, and is composed of mudstones
below with sandy shales above, at the base of which the characteristic
calcareous concretions are found. Towards the summit it becomes
more sandy and passes into the Wenlock Limestone. This rock is
only 40 feet thick here and is composed of thin limestone bands with
sandy partings, and cannot be called a coral reef. It occurs in
isolated strips as it is much broken by the faulting, and has even
been pushed into the more yielding shale beds.
The Ludlow Beds are 1,300 feet thick; they pass downwards
conformably into the underlying Wenlock, and are composed of
impure sandy shales followed by sandstones. ‘There is no Aymestry
Limestone nor any sign of the Aymestry fauna, and the Ludlow rocks
eannot be divided into an upper and lower series. This great
thickness of Ludlow Beds at Usk shows a striking contrast to the
Tortworth inlier, where they have been in great part removed by
erosion.
In the appendix by Dr. Cowper Reed several new species and
varieties are described, including new species of Chonetes ( C. ceratoides),
Pteronitella (P. inexpectata), Gosseletia (2) [@. (2) Zawneyt |, Pholadella
(P. Me Coyi), and new varieties of Proetus Stokesi, Murchison, and
Phacops Stokesi, Milne Edwards.
The paper is illustrated by a geological map and two plates of
photographs of the fossils described by Dr. Cowper Reed.
W. H. Witcocxson.
TV.—Artantis. By Pizrre Termirr. Smithsonian Report for 1915,
pp- 219-384.
ft this publication, which is a translation of a lecture given before
the Institut Océanographique of Paris on November 80, 1912,
the author puts forward the evidence in favour of accepting the
Platonian account of the destruction of Atlantis as materially true.
After giving a general account of the old legend, with quotations
from Plato’s Timeus, the author reviews the geological and zoological
evidence for the former existence and recent disappearance of the
Atlantic Continent. He argues that land must have existed along
the lines of the Alpine and Hercynian folds, and also further south
along the northern border of the old Gondwanaland, and that this
land must have gradually foundered, the old E.—W. lines giving
place to the present N.-S. line, as shown by the bank which runs
from north to south down the centre of the Atlantic Ocean. This
bank, and the similar banks off the coast of Africa, are connected
with volcanic and seismological phenomena as shown by the volcanic
islands which are situated on them; and the deeps on either side of
it bear the same relation to the volcanoes as do the deeps off the
western coast of America to the Cordillera of the Andes. The
presence of undisturbed Miocene beds in the Azores and Canaries
shows that land existed in the neighbourhood of these islands in
Miocene times, but the writer regards as the chief point in favour of
recent submergence the fact that a cable ship in 1898 dredged up
some fragments of tachylyte from the sea bottom about 500 miles
i
474 Reviews—Earthquake of Marsica.
north of the Azores. This, he says, must have solidified on the
surface of the land, as it would have solidified at least into a erypto-
crystalline condition at the depth of 8,000 m. where it was found,
This fact, coupled with the great inequality and rocky character
of the ocean floor at this spot, where the ooze only lies in the
hollows, shows that the submergence must not only have been recent
but also sudden, as there had been no time for the inequalities of the
surface to be eroded.
Turning to the zoological evidence, the author quotes work by
M. Louis Germain to show, firstly, that the terrestrial fauna of the
Azores, Madeira, the Canaries, and Cape Verde Islands is of conti-
nental origin, and shows evidences of adaptation to desert conditions.
Secondly, that the Quaternary formations of the Canaries and
Mauretania contain the same species of Helix. Thirdly, that the
mollusea of the four archipelagoes have affinities with the Tertiary
mollusca of Kurope; and, fourthly, that the Oleacinide group of
pulmonate mollusca is confined to the Mediterranean basin, the
Azores, Canaries, Madeira, the West Indies, and Central America.
All this evidence seems to demand the existence of a continent
connecting Europe and Central America which gradually disappeared,
beginning with the westerly portions and leaving the easterly portions
till the last, and the author considers that it is quite conceivable, if
we take into account the unstable condition of the Atlantic voleanic
areas, that the final disappearance may have been witnessed by man,
and have been so sudden as to constitute a ‘‘ cataclysm ’”’.
W. H. Witcocxson.
V.—THe Harruquake in: THE Marsica, Cenrrat Itary. By
Professor Ernesto Mancrnt. Smithsonian Report for 1915,
pp. 216-18.
N January 13, 1915, the Marsica, a district in the southern part
of the Aquilian Abruzzi, was devastated by a very severe
earthquake. The region of the Marsica which was the epicentre of
the disturbance is situated on the line along which, according to the
Japanese seismologist Professor Omori, the chief earthquakes in Italy
have been distributed. The district is essentially sedimentary and
of Karstic origin, so that a volcanic origin is impossible, and the
shock seems to have been caused by two separate deep-seated move-
ments which took place either simultaneously or in very quick
succession along a line having a north and south trend, some sixty or
seventy miles east of Rome. The shock was of such intensity that
the seismograph at Rocca di Papa was dismounted, as also would
have been the instrument at Rome had it not been provided with
special stop screws. The details of the seismic waves have been
worked out by Professor Oddone. Their period was 0°7 second,
their wave-length 20 metres, and their amplitude 20 centimetres.
' The damage to buildings was caused by a bulging movement of the
ground, accentuated by eddying motions due to the combination of
longitudinal and transverse vibrations coming from the hypocentre
to the epicentre at the surface.
Reviews—Central Scotch Coalfield. AT5
The number of victims is eeunaated at 25,000, at Avezzano 10,700
being killed out of a total population of only 13, 000.
W. H. Wicocxson.
Vi.—La Lieve pr Depresstons Reana-VerIn rr ses Sources
Carponatiys. By P. Cuorrar. Extrait du tome xii des Com-
municagées do Servigo Geoldgico de Portugal. Lisbon, 1917.
(J\HE Gallaico-Durian massif of the North of Portugal is traversed
. by a curious line of depressions, with which are associated
a considerable number of mineral springs particularly rich in
carbonates. The country rock consists of Pre-Cambrian schists and
Cambrian sediments, both being penetrated by granites, supposed to
be of Hercynian age. Although the evidence is not very clear, the
springs probably have some genetic connexion with the fractures
that determine the lines of depression.
R. H. Rasratt.
VII.—THr Economic Grontocy or THE CENTRAL COALFIELD OF
Scorranp. Area VIII: Easr Kireripe anp THE QuarreEn.
Mem. Geol. Sury. Scotland. pp. iv-+52, 1 fig. and 2 plates, 1917.
Price 2s.
f{\HIS is the second memoir of a series of which the first was
recently noticed in these columns (Gror. Mac., September,
1917, pp. 426-7). It follows precisely the same lines as its pre-
decessor, and contains an interesting account of the strata of the
East Kilbride district, which are mostly of Lower Carboniferous age,
resting on the plateau basalts. Only at the extreme east of the area
is there a small patch of Upper Carboniferous rocks. The very fine
sections in Calderwood Glen are described in detail, and special
attention is paid to the discovery first made by Mr. Carruthers that
here plants of undoubted Calciferous Sandstone age are associated
with Posidonomya Bechert and Aviculopecten papyraceus, thus showing
that in Scotland the Pendleside facies occurs very low down in the
Lower Carboniferous. At the present time the economic productions
of this area are of small value, and the interest is mainly strati-
graphical and paleontological.
Wy. del, des
VIII.—Motysprenum in Natat.
N the South African Journal of Science for November, 1916,
Mr. A. L. du Toit describes a curious occurrence of molybdenum
ores in a sandstone belonging to the upper part of the Karroo system
(Molteno Series). The molybdenum minerals occur as an impregna-
tion in quite a limited area, in association with iron pyrites and
marcasite and some carbonaceous material. The minerals that have
been identified are molybdenite, molybdic ochre, and ilsemannite,
the two latter being apparently oxidation products of the sulphide.
The origin of the deposit is not clear: it does not seem to be detrital,
as the patch is well defined from the rest of the rocks; there are no
dykes or any indication of channels by which solutions could have
476 Reviews—Oaleite in Silrcrfied Wood.
ascended. About 100 feet higher in the Molteno Series is a dolerite
sill of the usual Karroo type, and the mineralization may possibly be
due to this phase of igneous activity.
Ra Hie
IX.—A REMARKABLE OCCURRENCE OF CatciTE IN Sinicrrrep Woop.
By Epear TT. Wuerry. Proceedings of the United States
National Museum, vol. li, pp. 227-80.
N 1915 Mrs. Charles D. Walcott collected in the Yellowstone
National Park a piece of silicified wood of Sequoia magnifica
(Knowlton), in which were numerous white grains with rhombic
erystal outlines and dark central inclusions. When thin sections of
the wood were examined the grains were found to consist of calcite,
occurring sometimes in simple crystals, but more frequently twinned,
often polysynthetically. The development of the crystals shows some
interesting features. In the centre there is generally an inclusion of
woody cells, distorted either very little or not at all, then comes
a layer of clear calcite with woody fibre which occasionally extends
along the boundaries of the twin lamelle; outside this, just within
the crystal, there is often a zone of disrupted cells, and finally
outside the boundaries of the faces, which are often curved, is a dark
compact band of tissue. The fibre round the crystals shows little or
no distortion, each cell being filled with a single quartz crystal; this
shows that the calcite must have been deposited before the quartz
and when the wood was so rotten that pressure was not transmitted
through it for any distance.
The history of the specimen seems to have been as follows: —The
rotten wood was permeated by solutions containing calcium carbonate,
which at first deposited calcite quickly at certain places round the cells.
Then, later, deposition became slower and the cells were pushed
outwards by the growing crystals to form the dark band round the
edges. After a break in the deposition a final layer was deposited
so as to include some of the broken tissue on the edges of the crystals,
and finally the calcareous solutions gave place to “siliceous solutions
which deposited quartz in the remainder of the tissues.
W. H. Witcockson.
X.—Txe Royat Society Cros.
N the Annals of the Royal Society Club, the record of a London
dining-club in the erghteenth and nineteenth centuries (Macmillan,
pp. xv, 504, 1917, price 18s. net) Sir Archibald Geikie has published
a volume packed with biographical interest. Although such a book
can at best be but arecord of fact, still there is a certain amount of
general interest within these covers. From various accounts one
gathers that almost from 1650 certain members of the future Royal
Society (1662) met together at taverns to discuss their interests, but
the earliest surviving document relating to the ‘‘ Club” dates from
October, 1743. Since then the weekly dinner regularly continued
for sixty years, and the most curious portion of these records consists
in the bills of fare faithfully entered up week by week for more than
Reviews—Brief Notices. ATT
forty years of the eighteenth century. Further interest will be found
in the names of and notes on the numerous geologists, both British
and foreign, who were admitted as guests to the dinners, with the
curious un-British arrangement that they had to pay for their
own food.
The book demanded wide knowledge and reading, and there are
but few slips. Huxley died in 1895, Carpenter (p. 402) was W. B.,
and Horsley died in Mesopotamia. The statements on p. 428 are
unfortunate.
XI1.—Brier Notices.
1.—A ConrrisuTion To THE INVERTEBRATE FAUNA OF THE OLIGOCENE
Breps or Fuiint River, Grorera. By Wittram Heater Dat.
Proc. United States Nat. Mus., vol. lh, pp. 487-524, with
pls. Ixxxui—vili, 1916.
[* this work the author recognizes two zones, an upper and a lower.
‘The former has yielded 61 species, of which 29 are new, while
the lower zone has furnished 39 species, among which 9 are new.
Five of the new species and 14 of the others are said to be common
to both zones. A useful distribution table is given of the fauna
showing the occurrences of the various species in both zones and
their presence in the Ocala, Vicksburg, Orthaulax, and Chipola
horizons. The fauna described is entirely molluscan, comprising
Pelecypoda, Gasteropoda, and Scaphopoda.
2.—MoLiusks FROM THE TYPE LOCALITY OF THE CHOCTAWHATCHEE
Mart. By Wenpert C. Mansrretp. Proc. United States Nat.
Mus., vol. li, pp. 599-607, pl. exiii, 1916.
({\HE fauna here described is made up of Pelecypoda, Gastropoda,
and Secaphopoda, having been collected in the Choctawhatchee
Marl, regarded as of Miocene age, occurring near Redbay, Walton
County, Florida. Descriptions and illustrations are given of the
following new species of Pelecypoda: Arca (Scapharca) staminea,
Say, new sub-species rubisimana, Leda choctawhatcheénsis, Phacoides
(Pleurolucina) choctawhatcheénsis, Astarte (Ashtarotha) Vaughani, and
Diplodonta waltonensis. The complete fauna of this deposit is tabu-
lated so that the range of the species is shown from Oligocene to
Pliocene times.
3.—TuHE SHetis or tHE Hoitperness Basement Crays. By ALFRED
Bett. Zhe Naturalist, 1917, pp. 95-8, 135-8.
f[\HIS paper furnishes a revision of the published lists of Mollusca
from these deposits, with criticisms and remarks on the
determinations and nomenclature. Of the 180 molluscs recorded, it
is stated that at least 100 are no longer living south of the Shetlands,
while the remainder mostly belong to Arctic Norway. Relationships
of the Mollusca are noticeable in the Bridlington and Chillesford
Beds.
478 Obituary—Alfred Nicholson Leeds.
4.—New Mereorires.
i R. GEORGE P. MERRILL in the Proceedings of the United
i States National Museum describes two new meteorites. The
one (vol. li, pp. 525-6) is interesting because it was dredged up
from Lake Okechobee, Florida, by a fishing net, and may possibly
be a fragment of a meteorite which fell in that region about thirteen
years ago. The stone is still firm and shows the characteristic.
crust. Under the microscope the chondritic nature of the stone is at
once evident. Altogether the various fragments secured amount to
about 1,100 grams. The other meteorite (vol. lii, pp. 419-22)
consists of three fairly complete individuals and a fragment, and
weighed altogether 7,605 grams. It is of the usual chondritic type,
but the finer details of the structure are obscured by oxidation. It
was found near Plainview, Hale County, Texas.
OBITUARY.
ALFRED NICHOLSON LEEDS, F-.G:S.
Born Marcu 9, 1847. Disp Aucust 25, 1917.
(WITH A PORTRAIT, PLATE XXXI.)
We regret to have to record the death of Mr. Alfred N. Leeds, one of
the most successful pioneers in the modern methods of collecting and
preserving fossil vertebrate skeletons. For nearly half a century he
had devoted his leisure to recovering the remains of fossil reptiles and
fishes from the brickfields in the Oxford Clay near Peterborough ;
and the thoroughly scientific and painstaking nature of his work can
be appreciated at once by a glance at the unique series of specimens
which he contributed to the Geological Department of the British
Museum (Natural History).
The second son of Mr. Edward Thurlow Leeds, of ie Sbary,
Peterborough, Alfred Leeds was born in his ancestral home seventy
years ago. He was educated at the Warwick Grammar School, and
afterwards desired to follow a medical career; but circumstances
necessitated his assuming the management of the Eyebury farm, and
from 1868 onwards this was his daily occupation. His elder
brother, Mr. Charles E. Leeds, who was then studying at Oxford,
received encouragement from Professor John Phillips to persevere in
the collection of fossils round his home which he had already begun.
A large part of a Plesiosaurian skeleton which he had discovered was,
indeed, described by Phillips in his Geology of Oxford and the Thames
Valley (1871). Under such stimulus he was soon joined by Alfred
Leeds, and the two brothers gradually perfected methods of extracting
the skeletons from the soft clay which were more scientific and
thorough than had ever been attempted before. By liberal rewards
they induced the workmen not to dig up bones themselves, but to
send notice of each discovery to Eyebury. One or both the brothers
would then disinter the specimens with their own hands, noting the
mode of occurrence of every fragment and clearly distinguishing the
Grou. Mac., 1917.
Prath XXOXT.
Photo, Lafayette.
| fon fh
Obituary—Alfred Nicholson Leeds. == 479:
parts of each individual skeleton. Next they cleaned, washed, and
pieced together the broken fragments at home; and they kept such
exact records that if any parts proved to be missing they were able
to return to the place of discovery and very often supply the
deficiencies. Some of the larger skeletons, in fact, were so widely
scattered that they could only be recovered bit by bit in the course
of weeks or months as the clay was worked; but the brothers’
records were so well kept that even in these difficult cases the missing
parts of most remarkable specimens were eventually obtained.
In 1887 Charles Leeds emigrated to New Zealand, where he died
in 1912 (see Gror. Mac., Dec. V, Vol. IX, p. 287). For the last
thirty years, therefore, Alfred Leeds worked alone, aided only in the
delicate processes of preparing specimens by his accomplished wife
and by one of his sons, EK. Thurlow Leeds, now of the Ashmolean
Museum, Oxford. The scientific value of his results was acknowledged
by the Council of the Geological Society in 1898, when they awarded
to him part of the Lyell Fund.
Although Mr. Alfred Leeds never ventured himself to write about
his discoveries, he soon became well versed in the osteology of the
Mesozoic reptiles and thoroughly appreciated most of the novelties
which he met with. He handed over all his material, with his own
observations, to various specialists who were in friendly communica-
tion with him. His collection was thus described by J. W. Hulke,
H. G. Seeley, R. Lydekker, C. W. Andrews, and A. S. Woodward,
and was also used for reference by O. C. Marsh, G. Baur, and others.
Among Dinosaurs he obtained important remains of Omosaurus and
Stegosaurus, and especially fine portions of the skeleton of Cetvosaurus,
including a fragment of the slender whip-shaped end of the tail like that
of the American Diplodocus. He was the first to find sufficiently
extensive series of Pliosaurus to show the true nature of that gigantic
marine reptile. He also discovered two closely related new genera,
which were named Peloneustes and Simolestes by Lydekker and
Andrews respectively. His wonderful collection of Plesiosaurians
‘and Ichthyosaurians enabled Seeley to determine for the first time
the characters of the pectoral arch of these reptiles; and he dis-
covered several growth-stages in the Plesiosaurians as described by
Andrews. Among Crocodilians he obtained a unique series of more
or less nearly complete skeletons of Detriorhynchus and Steneosaurus,
showing that the former differed from all other known Crocodilians
in its complete adaptation to aquatic life, lacking bony scutes, and
having the tip of the backbone turned downwards to support
a vertical tail-fin as in the Ichthyosaurians. From 1890 onwards all
the most important of these specimens were gradually acquired by
the British Museum, and an exhaustive Descriptive Catalogue of the
Marine Reptiles, prepared by Dr. Andrews (with illustrations), was
published officially in two volumes in 1910 and 1913.
The fishes discovered by Mr. Leeds were no less important than
the reptiles, on account of the manner in which they displayed the
separate bones, especially of the head. They include several new
species described at different times by Dr. A. S. Woodward. The
most striking new genus and species is Leedsia problematica, the
480 Miscellaneous.
largest known ganoid fish, probably about 30 feet in length and with
a tail (now exhibited in the British Museum) 9 feet in span.
Remains of IMestwrus add much to our knowledge of the Pyenodont
fishes; while the bones of Lepidotus, Caturus, and Hypsocormus can be
handled and studied almost as in specially macerated modern
skeletons. Among sharks, there is the first proof that the fin-spines
named Asteracanthus and the teeth named Strophodus belong to the
same fish. Like the reptiles, all the most important fishes are now
in the British Museum; but there were enough duplicates of both
groups to provide for many other museums, and these are to be found
both in this country and in Germany, Austria, and North America.
Those who had the privilege of Mr. Leeds’ friendship will always
retain happy memories of the hospitality of Mrs. Leeds and himself
at Hyebury. He lived in the picturesque fenland farm that was
formerly attached to the Abbey of Peterborough, and the thick walls,
with a remnant of the moat, were an interesting memento of other
days. His museum occupied the attics of the house, and the old
farm-office was always filled with boxes of the latest discoveries
awaiting preparation. Odd trays of specimens in progress were also
kept in sight in other rooms to occupy leisure moments. His
interests, however, were by no means confined to his fossil bones.
He was alive to the progress of science in all ways, and he took an
especially active part in local affairs. His loss, indeed, will be
mourned by the whole community.
Ai Sie
MISCHIIMAN HOUS.
Toe Purrocenr Cave at Dove Hores.—EKarly in August last
Professor Boyd Dawkins and Dr. Smith Woodward visited the
Victory Quarry, Dove Holes, near Buxton, where Pliocene mammalian
remains were found in 1902 in a small cave or fissure in the
Carboniferous Limestone (Quart. Journ. Geol. Soc., vol. lix, pp. 105—
29,1903). Although the fissure in question has long been emptied
and destroyed, several similar fissures, filled with clay and sand, are
still to be seen; but no fossils appear to have been met with in these
deposits during the past fifteen years. The foreman and some other
workmen who helped to find the teeth and bones described by
Professor Boyd Dawkins are still employed in the quarry, and haye
received every inducement to be watchful for similar discoveries.
Pitrpown.—During the past summer Dr. Smith Woodward has
spent six weeks, partly in association with Professor Elliot Smith
and Major Cromer Ashburnham, in exploring the Piltdown gravel.
Large excavations were made round the edge of the original pit in
which the remains of Piltdown man were found, and much undis-
turbed gravel was sifted and carefully examined. Nothing, however,
was discovered except one unimportant fragment of the tibia of
a deer. The second locality in which the late Mr. Charles Dawson
picked up fragments of a Piltdown skull has not yet been identified
with certainty, but hopeful inquiries are still being made.
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I. ORIGINAL ARTICLES. Page III. REVIEWS "Page ©
Boring for Coal at Presteign, Professor A. C. Seward: Fossil
Radnorshire. By T.C. CANTRILL, Phamitiss avo: Delia esata san setae 516 _
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"| BRypoNz,F.G.S. (Pl. XXXII.) 492 Nakajima bars onc eeceeey eee . 520
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| Ambrym Island, New Hebrides. - Blue) sQuarie- 2 sees eee 521
at By the Rey. M. PRATER ......... 496 | Magnesite Deposits Grenville,
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| The Albertella Fauna. By L. D. Professor Edward Hull :.............. 528
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THE
GHOLOGICAL MAGAZINE
NEW SERIES, (DEGADE: Viet aWOl IN:
No. XI.—NOVEMBER, 1917.
ORIGINAL ARTICLES.
I.—On a Bortne For Coat at Presreren, RADNORSHIRE.
By T. C. CANTRILL, B.Sc. Lond., F.G.S., of the Geological Survey of England
and Wales.
N March, 1912, a short paragraph in one of the London daily
papers made the astonishing announcement that several beds of
coal had been discovered on the Folly Farm, Presteign, and that
boring would be started immediately. The astonishment was due to
the fact that on the Geological Survey maps Presteign is represented
as surrounded by Silurian and Old Red Sandstone formations, with
no rocks of Carboniferous age nearer than the Clee Hills, 20 miles
away in Shropshire. Unless, therefore, the Survey maps were
wrong, and some unsuspected outlier of Coal-measures had been
discovered, the name of the scene of operations was likely to prove
prophetic. :
While staying at Llandrindod in June following, it came to my
knowledge that the proposed boring had not only been begun but
had already reached a depth of several hundred feet. I therefore
agreed to the suggestion of a resident of Llandrindod, interested in
the scheme, that I should take the opportunity of visiting the bore-
hole and reporting on its prospects. This I accordingly did on
July 2, 1912, and found that it had been carried down through
a series of mudstones, grits, and limestones, to a depth of 540 feet.
Silurian fossils were found to be abundant in the rocks at the surface,
and were present also in the cores brought up from various depths in
the borehole. Yet in spite of my having at once submitted a report
to this effect to one of the active promoters, urging him to abandon
the scheme, the boring was not only continued to a total depth of
8884 feet, but was followed up by the cutting of a drift for some
distance into the foot of an adjacent ridge of Wenlock Shales, Wool-
hope Limestone, and Upper Llandovery Sandstone.
It is scarcely necessary to say that, so far as the finding of coal is
concerned, all these operations were foredoomed to failure, as the
Silurian rocks contain no coal.!
The site of the boring? lies about 170 yards N. 174° W. of the
1 There is at least one simple precaution that can be taken by anyone before
yielding to the temptation to invest in local coal-mining ventures in districts
remote from the coalfields. Let an inquiry be addressed to the Geological
Survey Office, Jermyn Street, London. A brief, civil, and possibly useful
reply will be obtained at the cost of a penny stamp.
2 The district is contained in the 1 in. Old Series Ordnance and Geological
Map, Sheets 56 N.E. and S.E.; in the 1 in. New Series Sheet 180; and in
the 6 in. Map of Radnorshire, Sheet 25 (Herefordshire 10) N.E.
DECADE VI.—VOL. IV.—NO. XI. ol
482 T. C. Cantrill—Coal-boring at Presteign, Radnorshire.
Folly Farm, three-quarters of a mile south of Presteign. From
the eastern suburb of the town a lane, turning southward out of
the Tenbury road at the County Intermediate School, crosses the
railway and rises towards the ridge of Nash Wood and Corton. At
the foot of the ridge the lane bends to the south east, climbs the
Folly Bank by a diagonal course close to the site of the boring, and
soon reaches the summit at the Folly Farm (Fig. 1).
Muir ORIFT
2.
Fic. 1.—Sketch-map of the neighbourhood of Folly Farm, Presteign. Scale
6 inches toa mile. B.H., bore-hole; W.L., Woolhope Limestone.
The mouth of the drift can be seen at the foot of the ridge, about
60 yards west of the bend in the lane, and 140 yards west-by-north
of the borehole. ‘The excavation was driven in a direction bearing
about S. 16° W., i.e. at right angles to the trend of the ridge, and
descends at a shght angle from the horizontal. It thus cuts the
beds in descending order at about right angles. Judging by the
amount of material brought out, it must have penetrated a consider-
able distance into the hill-side before it was abandoned through
lack of further funds.
Murchison? in 1889 sketched the outlines of the geology of
Presteign in the classic pages of Zhe Silurian System. He clearly
perceived the anticlinal structure of the Nash and Corton ridge, and
its connexion with the disturbed region of Old Radnor. He saw
that the visible core of the ridge is composed of grits and con-
elomerates, which he correlated with the upper beds of the Caradoc
Sandstone of Shropshire, and that these grits rise on each side from
beneath a calcareous zone, which he regarded as the equivalent of
the Wenlock Limestone. He noted also that the grits contain the
characteristic fossils of the upper beds of his Caradoc Sandstone,
e.g. Pentamerus oblongus and P. levis, and that the overlying lime-
stone, which, on the northern side of the ridge,” occurs in the form
1 Silurian System, pp. 313, 314, 321, 322.
2 This outcrop has been variously referred to as the limestone at the Folly
(Murchison), at Folly Bank (J. E. Davis), at Corton (Murchison and W. 8.
Symonds), and at the Sandbanks (J. E. Davis). It will facilitate description
a
tase
T. C. Cantrill—Coal-boring at Prestergn, Radnorshire. 483
of nodules and two thin bands subordinate to shale, yielded (to quote
the original nomenclature) Asaphus caudatus, Calymene variolaris,
C. macrophthalma, and Isotelus.
For the most complete geological description of the district the
inquirer must turn to a paper read before the Geological Society of
London in May, 1850, by J. E. Davis,' apparently only a month
before the first issue of the Geological Survey map. The purpose of
the author was to show that the limestone of Nash and Presteign
is of Wenlock age, as had been stated by Murchison in 1839, and not
of Woolhope age, as Sedgwick had surmised as a result of a visit
in 1846. Incidentally we gather that on the northern side of the
Corton ridge the limestone formerly quarried at ‘the old and now
abandoned excavations . .. at the ‘Sandbanks’”’ is about 8 feet
thick, is highly crystalline, is separated from the Caradoc Sandstone
by a few feet of shale, and is overlain by a greater thickness of
Wenlock Shale. He pointed out that the sandstone contains
abundant specimens of Pentamerus oblongus, Sow., Atrypa hemispheriea,
Sow., and various species of Orthis. From the limestone of the Sand-
banks he recorded only Orthis pecten ?, Dalm., Lingula quadrata ?,
Hichw., and Orbicula Forbest, Dav. He gave a long list of fossils
from the Wenlock Shales of the Sandbanks, and remarked that
fragments of Bumastus barriensis (Murch.) [=Jllenus barriensis |
occur in great abundance.
The first edition of the Geological Survey map (56 N.E.), undated,
but published probably in 1850, showed the Corton ridge as an
anticline of ‘‘Caradoc Sandstone”’, with a band of ‘Silurian
limestone”’ dipping off its northern foot and succeeded by the
Wenlock Shale. On a later edition (dated June, 1850, though
probably this date refers to the publication of the first edition) the
nomenclature is brought up to date, the term ‘‘ Caradoc Sandstone ”’
being replaced by ‘‘ Upper Llandovery Rock’’, while the lmestone
is definitely referred to as ‘‘ Woolhope Limestone”’.
In 1854 Murchison,? in his Sc/urza, an abridgment of his earlier
work, devoted a woodcut to a longitudinal section of the ground
lying between Corton and Presteign. He represented the Caradoc
[Upper Llandovery] Sandstone or Corton Grit as dipping steeply
northward under a group of shales with subordinate courses of
limestone, which he named ‘‘ Lower Wenlock Shale and Woolhope
or Lower Wenlock Limestone”. He thus tacitly relegated the
limestone to an horizon between the Caradoc and the Wenlock Shales,
and definitely correlated it with that of Woolhope. He also noted
that the Corton Grit is laden with the casts of Pentamerus oblongus.
In later editions of the same work $ he accepted the separation of the
if we call it the Presteign Limestone, or the Presteign outcrop of the Woolhope
Limestone. The other outcrop, on the southern side of the ridge, is known as
the Nash or Nash Scar Limestone.
1 **On the Age and Position of the Limestone of Nash, near Presteign,
South Wales’’: Quart. Journ. Geol. Soc., vol. vi, pp. 432-9, with a section,
1850.
2 Siluria, 8vo, 1st ed., 1854, pp. 89, 90, 102, 103.
3 e.g. in 3rd ed., 1859, pp. 101, 117, 118.
484 T. C. Cantrill—Coal-boring at Presteign, Radnorshire.
Pentamerus Beds from the Caradoc Sandstone, and adopted the term
‘Upper Llandovery Rock”’ for the Corton Grit, in which he noted
the occurrence of Pentamerus oblongus, Atrypa hemispherica, Petraia
elongata, and P. bina.
The Rev. W. S. Symonds’ appears to have been one of the first
observers to perceive that the Presteign Limestone is of Woolhope
and not Wenlock age. He based this conclusion on the facts that
here, as elsewhere, the limestone in question follows immediately
upon the ‘‘Caradoc” [i.e. the Upper Llandovery], and contains
Illenus barriensis and Homalonotus knighti in far greater abundance
than does the Wenlock formation. The same author, in a later and
better-known work,? remarked that as early as 1850 he had
correlated the Presteign Limestone with that of Woolhope by its
position with respect to the Upper Llandovery beds and from its
containing J//enus barriensis in abundance.
Turning now to the current edition of the Geological Survey maps
(Sheets 56 N.E. and 8.E.), we see that Presteign stands on a great
line of faulting, which, ranging in a south-south-westward direction
from beyond Church Stretton, runs through Bucknell in the Teme
Valley, passes Presteign, and, five miles farther to the south-west,
near Old Radnor, brings to the surface the ancient igneous rocks of
Stanner, Worsell, and Hanter.
On the western or downthrow side of this fault a broad strip of
Old Red Sandstone extends from Bucknell to within a mile of
Presteign. Though now cut through by the valley of the Lugg,
this strip was once continuous with a second tract of the same
formation, which underlies Upper Radnor Wood and Knill Wood,
south-west of the town.
On the eastern or upthrow side of the fault, grey calcareous sandy
mudstones of the Ludlow formation extend from Brampton Bryan
Park to within a mile of Presteign, where they give place to the
Wenlock Shales, though these are concealed for a space by the
superficial gravels and alluvia of the Lugg. Southward, beyond
these valley deposits, the lowest beds of the Wenlock Shales soon
emerge along the northern slopes of the anticlinal ridge of Nash
Wood and Corton. Fora distance of half a mile along the northern
foot of this ridge, and dipping northward from it at an angle of 41°,
a lenticular outcrop of the Woolhope Limestone comes to the surface
at the spot named Folly* on the Map (56 N.E.), thinning out to
a point, both eastward and westward, between the Wenlock Shales
above and the Upper Llandovery Rock below. Immediately south
of the limestone outcrop rises the Corton ridge itself, which consists
of Upper Llandovery Rock, locally known as the Corton Grit. Several
dip-arrows on the map show that the ridge is an anticline. It
1 Old Stones, 8vo, 1855, pp. 59, 60.
2 Records of the Rocks, 8vo, 1872, pp. 189, 140, 160.
> On the Ordnance Map, which was published October 1, 1833, this name is
placed at the northern foot of the ridge, where the lane from the town begins
its diagonal ascent. It may have referred to a cottage shown above the old
limestone quarries. The cottage is still remembered by old inhabitants,
but the name now applies to the farm on the crest of the ridge.
T. C. Cantrill—Coal-boring at Presteign, Radnorshire. 485
emerges from the flats of the Lugg near Corton, and trends south-
westward under Folly Farm and through Nash Wood toward Nash
Sear, where a second outcrop of Woolhope Limestone dips off its
southern flank and has till quite recently been quarried and burnt
for lime.
From these particulars, which for over half a century have been
accessible in the works quoted, it will be seen that a more hopeless
district in which to sink for coal could hardly have been found if
deliberately sought for. This is not the place to criticize the
pseudo-geological statements put forward in support of the scheme ;
it is sufficient to remark that one of the leading promoters regarded
the line of old excavations on the course of the Woolhope Limestone,
together with the presence of small pieces of unburnt coal in the
soil, as positive proof that the outcrop of a coal-seam had been at
some time worked there by opencast.
My hasty visit in July, 1912, and a brief examination made in
September, 1915, confirm in all their main features the views
expressed by previous observers; but the record of the boring shows
that the structure of the ground is not so simple as appears at
first sight.
The Corton Grit, consisting of hard and relatively durable
conglomerates, grits, and sandstones, forms the dominant feature of
the landscape. The rock has been extensively quarried at the
eastern end of the ridge, where a large excavation, 100 yards
north of Corton House, shows 30 or 40 feet of massive grits and
coarse grey sandstones. Quartz and quartzite pebbles are present,
and in some casesare claret-coloured. ‘The dip(E.S.E. at 15°) shows
clearly the pitch of the anticline. A rotten fossiliferous band about
half-way up the western face yielded ‘ Petraia’ elongata (Phill.).
In the lane that ascends the Folly Bank, past the boring, to the
Folly Farm, excellent exposures show a northward dip of 55°;
others, a few yards farther south, and within 70 yards of the site
_ selected for the boring, yielded specimens of ‘ Petraia’ elongata and
casts of Pentamerus oblongus, J. de C. Sow. On the southern side of
the ridge the same lane again shows the grits with Pentamerus,
dipping first eastward, and then south-eastward, at 20° to 30°.
The Woolhope Limestone has been at some time extensively
quarried and burnt for lime along the northern foot of the ridge.
The works had evidently been abandoned before the appearance of
J. E. Davis’s paper in 1850; but the quarries are clearly marked on
the Ordnance Map of 1833. As traces of several small earthen kilns
‘of horse-shoe shape can still be detected among the excavations, the
presence of pieces of coal in the soil is not to be wondered at.
Though little of the limestone is now visible, the old openworks
west of the lane show that the bed cannot exceed, if it attains,
12 feet in thickness, that it follows close upon the Corton Grit, and is
succeeded by mudstones referable, apparently, to the Wenlock Shales.
The high southern side of the excavation affords a fine view of the
grit, with large bare bedding-planes, dipping northward at 40° to
45°, and studded with quartz-pebbles of the size of peas. A specimen
of Favosites was extracted from one of these beds.
486 T. C. Cantrill—Coal-boring at Presteign, Radnorshire.
In the hollow left by the removal of the limestone only one small
exposure of that rock is now visible. It shows about a foot of
light-grey crystalline limestone, somewhat nodular and concretionary,
and apparently sheared and disturbed, overlain by 6 feet of olive-
green mudstones, containing flattened nodules of blue-hearted tough
argillaceous limestone, and dipping northward at 20°. These mud-
stones with nodules evidently form the base of the Wenlock Shales.
These basement-beds are again well-exposed at the western end of
the openwork, where they yielded a few fragments of graptolites,
identified as of the Monograptus colonus or If. dubius type by Miss G. L.
Elles, who suggests that the beds are not Wenlock but Lower Ludlow;
though how this can be so is difficult to explain, since the beds are
within 10 feet of the top of the Woolhope Limestone. Higher beds
are to be seen at the mouth of the drift (Fig. 1), where they dip
northward at 70° to 80°, and yielded Phacops caudatus (Briinn.),
Plectambonites transversalis (Wahl.), and crinoid ossicles.
The materials brought out from the drift show that the beds cut
through are the Wenlock Shales, the Woolhope Limestone, and the
Upper Llandovery Sandstone, as might have been expected. No
other rocks were seen on the tips, though it is possible, as will
appear later, that Archean rocks were reached. A specimen of
shale collected from this debris by Professor E. J. Garwood shows
a graptolite, which has been identified by Miss Elles as Monograptus
jieming? (Salt.) ; another graptolite she suggests is IL. vulgaris, Wood,
or JL. duévus (Suess). A piece of calcareous grit yielded Petraia sp.
Unfortunately the drift descends at aslight angle from the horizontal,
and in September, 1915, was derelict and full of water. It was
therefore impossible to make any examination or measurements of
the beds cut through, and no particulars appear to have been recorded
while the exploration was in progress.
From the details given above the identity of the rocks as Silurian
is put beyond doubt. But the structure of the ground is revealed
more clearly by the record of the boring than by the surface
exposures. ‘here is, however, strong suggestion of faulting in the
manner in which the outcrop of the Woolhope Limestone along the
northern side of the ridge comes to an end both eastward and west-
ward. The outcrop commences abruptly about 120 yards north-west
of the old Corton quarry (Fig. 1). It then runs obliquely up the
ridge through an old overgrown limestone quarry, crosses the Folly
Farm lane, and then traverses the long openwork already described
till it reaches the eastern boundary of Nash and Caen Wood, where
the quarrying seems to have stopped. But the strike of the beds
exposed at the western end of the openwork would carry the lime-
stone outcrop down the slope again towards the foot of the ridge,
where an attempt appears at some time to have been made to reach
it by shafts, one of which can be seen just within the northern edge
of the wood some 200 yards to the north-west. It is therefore
probable that the disappearance of the limestone in each direction,
after a course of only 800 yards, is due, not to thinning out, but to
faulting. This supposition is confirmed by the evidence of the
boring.
T. C. Cantrill—Ooal-boring at Prestergn, Radnorshire. 487
The boring (Fig. 2), which was begun on April 9, 1912, and
abandoned in the following autumn, is situated on the Wenlock
Shales, a few yards north of the outcrop of the Woolhope Limestone.
The following is the complete record as furnished by the firm who
carried out the work; for the classification and grouping of the beds
and for notes in square brackets the responsibility is mine :—
Bortne For Coat at Forty Faru, Prusteten.
New Series 1 in. Ordnance Map, Sheet 180 (Knighton); 6 in. Map,
Radnorshire, 25 N.K.; Geological Map (1 in.), 56 N.E.; Jat.52° 1554",
long. 3° 0’ 2”. Boring commenced April 9, 1912, abandoned before
October 7, 1912. Dip 55°, decreasing downward to 20°.
Thickness. Depth.
Wenlock Shales :— ft. in. ft. in-
1. Yellow clay [sandy, full of stones] . 4 4 " 11 6 ll 6
2. Soft yellow grey shale . : i ‘ : ; 3 & 15 0
3. Soft grey shale . : i 2 : : 2 0 17 O
4. Grey shale and hard balls ; : 4 ; : 12 6 29° 6
5. Grey shale . : 3 F : 3 : Q 8 29° 9
Woolhope Limestone and Sthoties —
6. Grey limestone, broken [ Woolhope Limestone] : 20 3 50 O
7. Grey shale with hard balls of limestone . : : 4 4 54 4
es Llandovery Sandstone :—
. Hard red grit with soft joints : ily 56 0
: Red-grey sandstone with lime and white ‘pebbles : 10 0 66 0
10. Red-grey sandstone with pebbles and vertical joints 10 6 76 6
11. Red-grey sandstone with shale and pebbles . 0 ly © 94 0
12. Reddish-grey sandstone . 4 0 98 0
13. Reddish-grey sandstone with ‘pebbles and pieces of
grey shale . : 6 0 104 0
14. Reddish-grey sandstone and pebbles é : : 10) 6) 146
15. Grey shaly sandstone and pebbles . : 6 : 10 6 125 O
Longmyndian (?) :—
16. Red-grey sandstone with pebbles and beds of green-
erey sandstone . : ‘ 10 0 135 O
17. Red-grey sandstone with white joints > : : 6 6 141 6
18. Hard red-grey sandstone with white eats 1 0 142 6
19. Soft grey sandstone 5 0 147 6
[Fault]
Wenlock Shales :—
20. Soft grey shale CO was: ©
21. Grey shale with spar veins 90) 164550
22. Grey shale with white spar veins "[Phacops ‘longi-
caudatus and Monograptus] 3 c c 46 6 210 O
23. Grey shale with spar veins 10 0 220 0
24. Grey shale with spar veins and partings . 5 6 225 6
25. Grey shale with white spar veins 9 6 2385 O
26. Grey shale with spat veins and partings . 29 0 264 O
27. Grey shale. ; Oo O 270) ©
28. Grey shale with 3 in. bed of sandstone : 4 0 274 O
29. Grey shale 9 0° 283 0
- 30. Grey shale with sandstone 1 inch thick . 1 0 284 O
31. Grey shale. : 7 © Pil Oo
32. Grey shale with black markings 9 0 3800 0
33. Grey shale with hard sandstone 16, © glo O
34. Grey shale with thin beds of grit it @ > ei¢ ©
35. Grey shale with beds of spar . 8°10) 335° 0
488 T. C. Cantrill—Coal-boring at Presteign, Radnorshire.
Thickness. Depth.
tie Te ft. in.
36. Grey shale and hard dark-grey grit CU SLIM:
37. Grey limestone . . ; : 2) 0°) 9343156
38. Dark-grey limestone and shale partings : : : 7. (6 Visa
39. Grey limestone. 5 : : 2). (Gy tsoameG
40. Grey shale with dark- -orey orit : : ¢ 8 6 362 0
_,41.° Grey shale with veins of fe : : : ; 20 0 382 0
42. Grey shale . : : : , : . 104 0 486 0
43. Grey shale with spar veins . ; 2 - ¢ 6 6 492 6
44. Soft grey shale . : : : 4 : ; 10° 0. 502-6
45. Grey shale . : c 3 3 ; : 5 6 508 O
46. Grey shale with spar veins . : : : é 80 7 2160
47. Grey shale . ‘ é 2 : Z : 12)* (6) O286
48. Grey shale, broken ; : : : , ; 47 9 5763
49. Soft grey shale . c : 0 : é : 8 3 584 6
50. Grey shale, broken : F ; : : ‘ 24 6 609 O
51. Grey shale . é : i ; : : 29. GI 2638 a6
52. Grey shale, broken 4 ; : ; : ‘ 10 0 648 6
53. Grey shale . j : ‘ : : ¢ 29) 6 167880
54. Fireclay : : : : : ‘ : é 3 0 681 0
55. Grey shale. : F : ; : ; 29" 0s) 7 1OURG
56. Grey shale and limestone : : j 3 ; LO) viel eeo
57. Grey shale. ; ; ; : : . 155, 6a S66
58. Grey shale, broken A é : : : : MO Ser. C
59. Soft grey shale : 3 11 6 888.6
At the time of my first ae the borne ea toate a depth of
540 feet. The cores, which were all of eel diameter, ranging
down from 3inches to 12 inches, had been laid out in order on shelves
in a small core-shed. JI broke up and examined samples taken by
myself from the cores at intervals of about 10 feet, but fossils were
disappointingly rare. Fragments of the trilobite Phacops longi-
caudatus ? (Murch.) were extracted from a core, 23 inches in diameter,
that came from a depth of between 180 and 200 feet, and Mr. John
Pringle afterwards found in the same sample a minute fragment of
a graptolite, identified by Miss G. L. Elles as Monograptus vomerinus
(Nich.) or its variety JZ. vomerinus (Nich.), var. crenulatus, Tornq.
Traces of small brachiopods and trilobites, too imperfect for identifica-
tion, were noticed at various depths. Additional samples of
mudstone and limestone from the cores were brought to the Geological
Survey Office in March, 1914, by a person interested, but as their
depths were not known, they threw no further light on the Silurian
sequence, though Mr. Pringle extracted from them some Pentamerid
remains and a fragment of Phacops.
It is scarcely necessary to add that no part of the cores examined
yielded a trace of a Carboniferous flora or fauna, and the record shows
that no seams of coal were found from top to bottom. ‘The solitary
bed called ‘‘ fireclay” (Item 54) can be dismissed as a band of sheared
and slickensided mudstone. The wonder is that more were not
recorded. 3
The interpretation of the section presents several difficulties.
Item 1 is probably in part ‘‘made ground” or rubbish thrown
down the slope from the old limestone workings, as it was said to be
sandy and full of stones. In Item 4 can be recognized the mudstones
with argillaceous limestone-nodules that overlie the Woolhope
T. C. Cantrill—Coal-boring at Presteign, Radnorshire. 489
Limestone in the openwork, as already described (p. 486). The
thickness of the limestone itself, aithough amounting to 20ft. 3in.
as cut by the boring, would, if measured at right angles to the
bedding, be somewhat less, but could scarcely be reduced to 12 feet,
the maximum space permissible in the openwork. It is possible,
therefore, that the thickness at the outcrop has been reduced as the
result of squeezing. The balls of limestone in Item 7 show that the
conditions that preceded the deposition of crystalline limestone were
similar to those which followed. ‘The boring agrees with the
surface exposures in showing the rapidity of the change from the
grits and conglomerates of the Upper Llandovery to the shales,
mudstones, and limestones of the Woolhope and Wenlock.
Item 8 forms the top of the Upper Llandovery Sandstone, and the
white pebbles in the next item identify this bed with one of those
exposed in the openwork. The cores, however, yielded no recogniz-
able fossils.
But while there is no doubt that the upper beds of Items 8-19
represent the Upper Llandovery Sandstone, there isreason to believe
that the lower of these beds are Longmyndian, and that a nucleus of
Archean rocks, directly underlying the Upper Llandovery, runs
through the Corton ridge, probably from one end to the other. This
suggestion is based on the following evidence.
Professor E. J. Garwood, during a visit at Easter, 1915, obtained
from the site of the boring a sample of rock to which special interest
attaches, on account of its strong resemblance to the conglomerates
of the Bayston Group of the Longmyndian System. -The rock is
represented by part of a 3 in. core, which, with this diameter,
must have come from the upper part of the boring. In the hand-
specimen the rock is a pebbly tough grit, of a purple and green
colour, composed of scattered subangular pebbles (up to 1} inches,
the majority being about half an inch in length) of purplish-red
quartzite approaching jasper in appearance, with others of white
quartzite, set in a greenish-grey matrix of small quartz-grains,
small greenish pebbles, and a greenish interstitial paste.
Under the microscope a slice of the rock (K. 11237)! shows that
while many of the small quartz-grains are angular, others are rounded,
and, as Dr. H. H. Thomas has suggested to me, appear to have been
derived from the detrition of a quartz-porphyry. ‘This is supported
by the fact that one of the quartz-grains is partly surrounded by
adherent glass. A few grains, about the size of the smaller quartz-
grains, are of silicified banded rhyolite. The small green pebbles
appear to be chloritic sediments; the interstitial paste seems to
consist of chlorite and quartz, with limonitic iron oxide. The rock
contains neither felspar nor calcareous matter.
A slice (E. 11236)! taken from one of the large pebbles of purplish-
red quartzite conspicuous in the hand-specimen shows that the
quartzite is thoroughly silicified, fine-grained, and contains many
skeleton rhombohedra after some slightly ferruginous rhombohedral
1 These numbers refer to the registered rock-slides in the collection at the
Geological Survey Office, Jermyn Street, London.
490 T. C. Cantrill—Coal-boring at Presteigns; Radnorshire.
carbonate. The purplish-red colour of this quartzite pebble is due
to a slight film of red iron oxide that coats most of the grains.
Having these characters, the rock represented by this core agrees
closely with some of the Longmyndian conglomerates, rather than
with the softer and calcareous grits of the Upper Llandovery. The
large diameter of the core and the fact that all the conglomerates
met with in the borehole lie between the depths of 54 ft. 4in. and
147 ft. 6in. lead me to refer the specimen to some unknown position
between these limits. Moreover, at 180-200 feet the core-diameter
was only 23 inches. The record is, however, not sufficiently detailed
to enable the base of the Llandovery to be located, though the
mention of ‘‘green-grey sandstone’? in Item 16 suggests Long-
myndian. I conclude, therefore, that while the upper part of the
93 feet of conglomerates, etc., is Upper Llandovery, the lower part
is Longmyndian. This is not at all improbable in view of the
outcropping of conglomerates of this age at Pedwardine,! 6 miles to
the north-east, and at Old Radnor,? 5 miles to the south-west; and
it is not unlikely that the claret-coloured pebbles in the Llandovery
grits of the Corton Quarry were derived from the neighbouring
Longmyndian conglomerates.
At 147ft. 6in. the boring passed abruptly into a thick series of
grey shales with a few thin grits and sandstones. Many of the beds
are described as broken and veined with spar. That these grey
shales are Silurian is proved by their yielding Phacops longicaudatus ?
(Murch.) and Monograptus crenulatus or its near ally IZ. vomerinus
at a depth of 180-200 feet. Mr. Philip Lake, to whom I am
indebted for an examination of the trilobite fragments, considers
that this species indicates a Wenlock horizon. Miss Elles thinks
that the graptolite shows the beds to be low in the Wenlock Shales.
It would seem, therefore, that the grey shales from 1473 feet down-
ward must be regarded as Wenlock Shales, and that the boring
passed into them from the Longmyndian through a fault (Fig. 2).
The 12 ft. limestone (Items 37-39) is probably a sporadic band and
ean hardly be the Woolhope Limestone, as it is underlain, not by
the Upper Llandovery Sandstone, but by 535 feet of what are
presumably more Wenlock Shales.
On this hypothesis a section through the borehole might be
represented diagrammatically as in Fig. 2.
It is improbable that the dip of 55° seen in the exposures of the
Upper Llandovery Sandstone close to the borehole prevails under-
ground. ‘The dip as seen in the cores below 1473 feet seems to vary
from 20° to 30°. From these rather meagre data the minimum
displacement of the fault may be estimated at 8884— 29% =
8583 feet, a throw that would carry down the Woolhope Limestone
to some position below the bottom of the borehole. And as the
Woolhope Limestone, Upper Llandovery, and supposed Longmyndian
in the boring overlie Wenlock Shales, the fault must be an over-
thrust from the south. The thrust-plane, which would reach the
1 A. H. Cox, ‘‘ The Pedwardine Inlier’’: Quart. Journ. Geol. Soc.,
vol. lxviii, 1912, p. 364.
2 C. Callaway, Quart. Journ. Geol. Soc., vol. lvi, p. 511, 1900.
T. C. Cantrill—Coal-boring at Presteign, Radnorshire. 491
surface along the foot of the ridge, accounts for the disappearance
of the Woolhope Limestone outcrop in both directions.
A
Zea
LEE
Ca Ze F
LEZ
BALE
G06.
200
Fie. 2.—Vertical section, in a north and south plane, of the upper part of the
Folly Farm Borehole, Presteign. , lane; BH, borehole; F-—F, over-
thrust fault; 1, 5, and 7, Wenlock Shales; 2, Woolhope Limestone and
Shales; 3, Upper Llandovery Sandstone; 4, supposed Archean (Long-
myndian) ; 6, 12 ft. limestone-band.
The Folly Farm boring and drift are not the first nor the only
recent attempts to find coal in the Silurian rocks of Presteign. Half
a mile farther west, and 350 yards east of Caen Wood House, a shaft
was begun in 1910, in the hope, as I was informed, of finding work
for local labour by the setting up of a new industry. The debris
from the shaft consists of light-blue and grey calcareous shales and
mudstones. These yielded nothing but an Orthis and a few frag-
ments of ill-preserved graptolites, doubtfully identified by Miss Elles
as Monograptus dubius (Suess) or IZ. colonus (Barr.); but the evidence
is perhaps scarcely sufficient to confirm the suspicion that the beds
are Lower Ludlow.
The operations at the Folly Farm have not added so much to our
knowledge of the local geology as might have been expected, but the
boring shows the existence along the northern foot of the ridge of at
least one important strike-fault, having the effect of thrusting older
492 Rh. M. Brydone—New Cretaceous Polyzoa.
rocks from the south over newer. The fossils yielded by the
mudstones in the borehole are few in number, but such as can be
identified suggest a low Wenlock Shale horizon for the deeper beds.
If the core believed by Professor Garwood to be Longmyndian is
correctly identified, the Upper Llandovery Sandstones of the Corton
ridge rest directly upon a nucleus of Pre-Cambrian rocks.
IJ.—Nores oN NEW AND IMPERFECTLY KNOWN OreEtacreous Poryzoa.
By R. M. BrYDONE, F.G.S.
(Continued from the April Number, p. 148.)
(PLATE XXXII.) .
ESIDES the series of Membraniporelle last described there are
several other Cribrilinidgee which develop a secondary aperture
in the same way, and the next four species are instances.
CRIBRILINA TRANSITA, sp. nov. (Pl. XXXII, Fig. 1.)
Zoarium unilaminate, adherent.
Zoecia of medium size, average length ‘7 to-75 mm. ; primarily
they are of the usual type with low slightly arched side walls and
arched front walls springing from the edges of the side walls, and
traversed by radiating furrows pierced in their outer half by short
and sometimes fairly broad slits, while at the inner ends there are
preserved very irregularly remains of a system of one or two
longitudinal rows of punctures ; six rows of paired furrows with or
without an unpaired one in the centre line seem to be the general
standard ; the aperture is roughly semicircular and its anterior lip
bears four tubercles ; in the secondary stage the side walls thicken
and rise, filling up the spaces between the front walls, but only
coalescing at occasional intervals; the secondary aperture is formed
as usual from a denticle in the centre of the posterior lip of the
primary aperture which is produced over this aperture as a flat wide
bar, from the end of which (and from the sides of the primary
aperture) there arises very steeply a thick ring leaving two slits on
either side of the denticle and embracing the front part of the
occium, on which the ring is flattened out somewhat angularly and
bears two small pores in the angles.
Avicularia small beak-shaped, narrow, and elongated, with strong
cross-bar close to the rounded end; a pair are generally placed on
either side of the secondary aperture with their beaks directed
inwards and generally more or less downwards and merging into the
ring surrounding the aperture; others are scattered irregularly over
the side walls.
Owcia large, globose, with small apertures cut well back, very
constant in occurrence.
This species is the only one in the group to show Cribriline
perforation, and this fact and its tuberculated primary aperture
suggest relationship to Cribrilina furcifera, Bryd.,! which itself
provides a half-way stage between this type of secondary aperture and
a simple aperture. It occurs quite rarely in the Uintacrinus band of
Hants and Sussex.
1 GEOL. MAG., 1910, p. 391, Pl. XXX, Figs. 6-8.
-
R. M. Brydone—New Cretaceous Polyzoa. 493
Cripritina T-ForMIS, sp.nov. (Pl. XXXII, Figs. 2, 3.)
Zoarvum unilaminate, adherent.
Zoecia rather small, average length -55 mm.; primarily they are
of the usual type with very low side walls and rather strongly arched
front walls traversed by radiating wholly imperforate furrows and
a distinctly concave posterior lip to the aperture which is widely
lenticular with a broad flat anterior lip; the furrows are very
shallow and sometimes cannot be detected over a whole zoccium ;
eight pairs seem to be the standard; in the secondary stage the side
walls rise to a level slightly above the edges of the front walls and
coalesce partly, but not wholly ; a denticle forms on the posterior lip
of the aperture and develops into a short rather narrow process
stretching upwards at a low angle over the aperture and then giving
off two branches, one on either side, at right angles to it, which
curve downwards and form the posterior lip of the secondary
aperture, whereby hiding the primary aperture; finally, the outer
edge of the anterior lip of the primary aperture is produced forwards
and raised slightly to form the thin anterior lip of the secondary
aperture, which is in a highly inclined plane. When the light is
from the foot of the zocecium the anterior secondary lip, if formed,
may be, and the primary anterior lip, if the secondary one has not
been formed, is almost sure to be, invisible in shadow, and the
zocecium appears to end abruptly in a suspended T, which is very
distinctive.
Oweva scarce, rather flatly globose, rather large in proportion,
with a wide aperture cut back rather sharply and squarely; some-
times the anterior lip of the secondary aperture rises and embraces
the greater part of them.
Avicularia small, beak-shaped, with spatulate anterior ends when
well developed, but accessory beak-shaped avicularia vary so much
in a single zocecium, according to their opportunities for development
and their state of preservation, that no importance can be attached to
variations in their appearance; they are scattered irregularly along
the side walls, but tend to occur in pairs pointing towards the
aperture from below and just touching the anterior lip.
This species occurs in the zone of Offaster pilula in Hants and
Sussex and does not appear to survive that zone, nor in those counties
to have any successor in the (restricted) zone of 4. quadratus, but in
the top beds of that zone in Suffolk it is succeeded by
Cripritina BeamMForDENsIs, sp.nov. (Pl. XXXII, Figs. 4, 5.)
This species is so closely allied to the preceding one that it is most
easily described by enumerating the differences between them.
C. Bramfordensis differs from C. T-formis in its greater size (average
length -8 mm.), its furrows deeply and squarely cut at the outer ends
and more numerous (nine or ten pairs being a minimum, while the
numerous small ones which can sometimes be detected round the
anterior end, coupled with the increase in numbers which automati-
cally accompanies any accidental increase in length, make it
difficult to put any limit to the number that might be met with), the
abundance of ocecia which are regularly overridden by the wide
494 Rh. M. Brydone—New Cretaceous Polyzoa.
anterior lip of the secondary aperture, and the higher angle of rise of
the anterior lip of the secondary aperture and the low angle of the
plane of the secondary aperture when no occium is present. The
sum of these differences is not over-convincing, but I think it is just
sufficient to support a specific distinction which marks a substantial
difference both in horizon and area.
The species occurs freely at the top of the (restricted) zone of
A. quadratus at Bramford, Suffolk, and there are indications that it
occurs rarely in the Weybourne and Trimingham Chalks.
MEMBRANIPORELLA SUBCASTRUM, sp. nov. (Pl. XXXII, Fig. 6.)
Zoarvum unilaminate, adherent.
Zoecia small, average length -6mm.; primarily they are of the
usual type, with low, slightly arched side walls, arched front walls
pierced by four or five pairs of short, narrow, radiating slits, and
a semicircular aperture; in the secondary stage there is the usual
formation of a secondary aperture from a denticle appearing on the
posterior lip of the primary aperture and from the uprising of the
latter’s sides; the side walls rise and thicken as usual and fuse with
one another and the margin of the secondary aperture and the
ocecia so as to form a broad network, enclosing and raised above the
front walls and encroaching on them so as to partly or even wholly
cover up the slits, and featureless except for (1) the secondary
aperture, which is more or less horseshoe-shaped with a strong
tendency to a small denticle on the posterior lip, and the anterior lip
formed mainly by the edge of the ocecium, which though incon-
spicuous is very regularly present; (2) the apertures on the side
walls of small avicularia merged in the general mass and present
fairly regularly at the lower corners of the secondary aperture and
also irregularly elsewhere; the edges of the secondary aperture run
a little way up the ocecium, but do not apparently unite across it.
Owcia large in proportion, rather flatly globose, with aperture only
slightly cut back.
This species is in nearly every respect an ill-defined ancestor of
Membraniporella castrum, Bryd.,' the latter is readily distinguishable
by its more numerous and conspicuous slits in the front wall, and its
curious cavity in the posterior lip of the secondary aperture, which is
indicated in the original figure, though not referred to in the original
description, and is very useful for rapid diagnosis. A figure of an
admirable specimen of Jf. castrum is given for comparison. JZ. sub-
castrum occurs rather scantily in the zone of Jlarsupites and the
subzone of #. sculatus var. depressus in Sussex. Specimens are
usually very obscure.
Mempranivoretta Gasina, sp. nov. (Pl. XXXII, Fig. 8.)
Zoarium unilaminate, adherent.
Zoecia narrow, but rather long, average length ‘75 mm.; the side
walls are almost common, only faint traces of a separate origin being
left, and are wide, especially at the ends, and the arched front wall
appears to be laid on them and to overlap their edges considerably at
1 GEOL. MaG., 1909, p. 398, Pl. XXII, Figs. 4, 5.
R. M. Brydone—New Cretaceous Polyzoa. 495
the anterior end; the aperture is heel-shaped with a tiny denticle on
the posterior lip, but it is often rendered more or less rectangular
by the intrusion of the edge of the occium at the anterior end;
along the edges of the front walls there are more or less paired
openings of varying size, a long pair about the middle of the front
wall being fairly regular in occurrence.
Oecia large, globose, and very flat; I have only seen them with
the shape of the aperture obscured or hidden by the margin of the
zocecial aperture.
Avicularia.— Small accessory avicularia with arrowhead-shaped
apertures when well preserved occur very consistently in pairs beside
or just above the zocecial aperture and pointing towards it, while
irregularly placed examples also occur.
This species occurs at the junction of the zones of 4. quadratus
and £B. mucronata in the Isle of Wight and in Hants, but is very
rare. Itis obviously not a Membraniporella in any ordinary sense,
but it appears at an horizon at which the Cribrilinide were unusually
active in development, and it is so simple in structure and so closely
analogous to many Cribrilinide, e.g. Membraniporella teniata,' that
I regard it as a highly aberrant Membraniporella.
CRIBRILINA REPLETA, nom. noy. (PI, XXXII, Fig. 9.)
Syn. ue ne suffulta, Bryd., GEOL. MAG., 1913, p. 437, Pl. XIV, Fig. 5
only.
I have come to the conclusion that my so-called ‘‘ coarse form”? of
Cribrilina suffulta cannot, owing to its erect side walls almost fused
together, be properly united with Cribrilina sujfulta, whose zoccia
are typically pyriporiform and quite separate. The relationship
between the two is, however, so very close that each is liable to
display here and there a considerable measure of the distinguishing
character of the other. JI have figured an exceptionally well-
preserved specimen which shows that the tubercles on the anterior
lip are typically four in number, long and tapering, but very brittle.
C. repleta, like C. suffulta, is nearly related to Semiescharipora inter-
rupta, D’Orb., which is distinguished from them by an aperture
longer than its width.
CRIBRILINA GALANTHIS, nom. nov.
Syn. a Gregoryi, Bryd., GEOL. MaG., 1913, p. 437, Pl. XIV, Fig. 3
only.
I have also come to the conclusion that my so-called ‘‘coarse form’”’
of Cribrilina Gregory? should also be specifically distinguished. It
differs from C. Gregoryi in the tuberculation of the anterior lip of
the aperture, which is very indistinct, but I now think consists of
traces of four tubercles only as in C. repleta (supra). It also differs
in a strong tendency to squareness in the shape of the outer pair of
the perforations in the front wall. Specimens occur occasionally in
the lower part of the subzone of ZL. scutatus var. depressus which are
very near C. Gregoryt, but are not definitely that species, and may
perhaps be referred to this.
1 GEOL. MAG., 1917, p. 50, Pl. II, Figs. 3, 4.
496 Rev, M. Frater—Voleanic Eruption, Ambrym I. sland.
EXPLANATION OF PLATE XXXII.
’ (All figures 12 diams.)
FIG. 1. Cribrilina transiens. Uintacrinus band. Brighton.
Broughton, Hants.
ae SA . T-formis. . Subzone of abundant Offaster pilula.
Jali Sahin AA Mi Subzone of H. scutatus var. depressus.
‘Rottingdean, Sussex.
», 4,5. Cribrilina Bramfordensis. Zone (restricted) of A., quadratus.
‘Bramford, Suffolk.
,, 6. Membraniporella subcastrum. Subzone of E Hi. scutatus yar. depressus.
Rottingdean.
GRUNT ER a8 castrum. Trimingham.
PB wb Gabina. Zone (restricted) of A. quadratus.
ai ibs Freshwater, Isle of Wight.
» 9. Cribrilina repleta. Zone of M.cor-anguinmum. Soberton, Hants.
It. —T ne Vortcanic Ervprion oF 1913 on Amprym Istanp, New
HeEsRIDES.
By Rey. M. FRATER.
(Communicated by Professor J. W. GREGORY, D.Sc., F.R.S.)*
(J\HE New Hebrides group of islands was first fully made known
to Europe by Captain Cook, who in the year 1774 spent
forty-six days among them. Situated in the Southern Pacific, about
1,400 miles N.E. of Sydney, the total number of islands is ‘nearly
eighty, the largest of which has a coastline of 200 miles. The islands
are. mainly of “yoleanie origin and lie in a direction from 8.8.E. to
N.N.W.. Volcanic action is almost exactly in the direction of the
group of islands, and a line drawn from the voleano of Tanna in the
south to the volcano of Tinakula in the north, a distance of 600 miles,
would pass through the volcanoes of Lopevi, Ambrym, Ureparapara,
and the boiling springs of Vanua Levu.
The line of volcanic activity which stretches across the Pacific
Ocean runs through the New Hebrides Islands. . Entering the
Pacific from the direction of Jaya, the volcanic belt passes through
Timor and extends to the large island of New Guinea, where it
bifurcates. _New Guinea seems to be a central focus from which
the lines of fissure girding the Pacific radiate; one line goes
northwards through Formosa and Japan, and the other southwards
through the Solomon Islands, New Hebrides, New Zealand to
Mount Erebus in the Antarctic Ocean.
1 [The MS. of this paper was left with me by the Rey. M. Frater on his
return to the New Hebrides for publication with some supplementary notes
on ‘the eruption after the arrival of his collection. The specimens have
been kindly sent me by Admiral Parry, the Hydrographer of the Admiralty,
and some account of. them will be included in the Report on the Eruption to be
published by his Department. This publication, however, may not be issued
until the end cf the War. Hence; it seems advisable to publish Mr. Frater’s
interesting account of the eruption without further delay. Mr. Frater acted as
euide and interpreter to Commander Hancock during the resurvey of Ambrym
after the eruption.—J. W. G.]
[The geological and petrological description of the Ambrym eruptions, by
Professor J. W. Gregory, will appear in the December Number, with a Map of
the Island.—EDIT. GEOL. Mag.]_
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PLATE XXXII
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Rev. M. Frater—Voleanic Eruption, Ambrym Island. 497
The volcanoes in the New Hebrides group work in sympathetic
agreement. ‘Tanna volcano is the Stromboli of the Southern Seas.
The eruptions of this volcano are still heard as in the days of
Captain Cook. There is the ‘‘pillar of smoke” by day and the
«pillar of fire” by night. It is the great lighthouse of the South
Pacific. Like a revolving light it bursts out every three or four
minutes with great brilliance. A few years ago the. regular
explosions suddenly ceased. The natives became alarmed; they
had become accustomed to regard the volcano as the safety valve
of the district, and they had sufficient knowledge of mechanics to
understand that the closing of a safety valve is as dangerous in
a volcano as in a steam-engine. In company with a crowd of
natives, the resident missionary climbed to the edge of the crater
and discovered that the walls had collapsed and choked the ‘‘fire”’.
But no sooner had Tanna closed down than the voleano on Ambrym,
300 miles northwards, became more active. The eruptions from
Ambrym, which had hitherto been spasmodic and irregular, now
took place at regular intervals, glowing at night with an intermittent
light resembling the flashing light of a lighthouse. Tanna remained
quiescent for a few weeks, and then, with a convulsive roar, the
imprisoned giant broke its bonds and awoke to life. The clock-
work regularity of the Ambrym volcano ceased and the eruptions
again became uncertain and spasmodic.
The same sympathetic relations which exist between Ambrym
and Tanna also govern the workings of the Ambrym and Lopevi
volcanoes. Situated on neighbouring islands, only 25 miles apart,
their operations can be watched together. Violent activity in the
one is almost invariably answered by outbursts in the other.
The destructive eruption of the Ambrym volcano with which
this paper deals occurred in December, 1913. Named Mount
Beabow, after one of the British warships which visited the group
in the early days of European settlement, the lofty cone of the
Ambrym volcano rises from the centre of an extensive ash plain,
over 2,000 feet above sea-level. In the neighbourhood of Mount
Benbow the ash plain is studded with a series of extinct craters,
occasional puffs of steam being the only indication of the pent-up
fire beneath. The ring-shaped crater wall which encloses the plain,
like a wall of circumvallation, first led the survey party of the
warship whose name the volcano bears to the now generally
accepted conclusion that the ash plain is the basal wreck of a
much loftier voleanic cone which was shattered by a volcanic
eruption, and that the island of Ambrym, with its volcanic soil,
now remains as a memorial to the destroyed volcano. For untold
centuries Mount Benbow had been at work puffing out steam which
at night refiected the glare of the molten lava bubbling within the
erater walls. So accustomed had the natives become to its presence
that the frequent outbursts occasioned ‘no surprise. They cultivated
the soil up to the edge of the ash plain at the base of the volcano.
But all unknown to the natives, and to the French and English
residents who had their homes on Ambrym, there stretched from east
to west across the island a belt of volcanic fracture. On this fissure,
DECADE VI.—VOL. IV.—NO. XI. 32
498 Rev. M. Frater—Volcanic Eruption, Ambrym Island.
hidden in many places, underneath a wealth of tropical vegetation,
stood the Presbyterian Mission Station, with its commodious and
well-appointed hospital. The site was one of the beauty spots of the
New Hebrides Islands. The hills around were covered with the
luxuriant vegetation of the tropics. Adorning the extensive clearing
which encircled the mission station, were wide-spreading banyan-
trees which had weathered the storms of centuries. Little did the
promoters of the Medical Mission imagine that they were building
over a slumbering voleano. Beyond the shape of the valley, which
was undoubtedly crateriform, there was nothing to indicate that
underneath the calm and luxuriance of external nature the forge of
Vulcan was being set up. In the light of recent events there can be
no doubt that the station was standing in the crater of an old volcano;
but it showed no trace of any recent eruption, and among the natives
no memory of any such catastrophe survived in the traditions of the
district. Countless generations, too, must have elapsed in the
populating of the crowded villages which thronged the district,
and in Captain Cook’s day the population was greater than it now is.
The symbolism and system of sorcery which had grown around the
native mythology was more intricate and subtle than that which
flourished in most of the other islands, and pointed to a long
succession of ages since fire had visited the district.
In December, 1913, the age-long sleep of the extinct volcanoes
near Mount Benbow was broken, and from numerous thunder-
throated vents the island was torn and rent with convulsive
explosions. The eruption was heralded by a series of premonitory
earthquake shocks. One of them, which occurred about a month
before the outbreak, was the most severe in the memory of the
natives. Immediately preceding the eruption, the shocks increased
in frequency and severity until the solid earth reeled and tottered.
The hospital buildings rocked like a ship at sea. The natives, in
their manner of speech, said that Ambrym danced. Then there was
seen to rise from the extinct craters a dense cloud which shot up into
the air and spread out in all directions like a gigantic mushroom.
Tremendous explosions followed each other in rapid succession.
Blacker and larger grew the cloud until it lay like a London fog
over the entire island. The erupting volcanoes followed the line
of volcanic weakness. Beginning at the extinct craters in the centre
of the island, the line maintained a westerly direction and every few
miles a new voleano burst out. From the neighbouring island of
Paama, where an unobstructed view of the eruption was obtained,
its rise and progress could be watched. In one place which seemed
to be a centre of disturbance, six volcanoes had formed within a short
distance of each other. During the night the track of the red-hot
lava could be seen like the trail of a serpent. Every outbreak
brought the eruptions appreciably nearer the hospital until in the
early morning, twelve hours after the first outbreak, the advancing
flare could be seen behind the hills which encircled the Mission
Station. At daybreak a dense black cloud was seen about a mile
behind the station, but the hospital staff imagined that the bush had
been set on fire by a lava stream. While they were watching it,
Rev. M. Frater—Volcanic Eruption, Ambrym Island. 499
a neighbouring trader who had two boys in the hospital arrived by
motor-launch and reported that it was a voleano which had burst
out. At the same instant, terrified natives from the inland villages
arrived with the news that the earth had opened some distance up
the valley and the molten lava had formed a lake of fire. They told
of villages blown up, of villages surrounded by fire, of hairbreadth
escapes from death. Most of the adults carried children. Large
numbers of old people had been left behind to perish. Preparations
were at once made for the removal of the patients. One of them,
the wife of a missionary, had given birth to a child a few hours
before, and she with her new-born son were the first to be rescued
from the doomed hospital. Another lady, the wife of a planter, had
her baby born when on the way to a place of safety. A motor-launch
was filled with the more helpless patients and sent, under the charge
of one of the assistants, to Malekula, an island 15 miles away.
The launch had scarcely left the beach when the engine stopped ;
a valve had jammed. After watching for a little the medical
superintendent rowed off in a small boat and, locating the trouble,
banged the obstinate valve down with a hammer. As he was
returning to the shore the doctor saw his wife and a number of
hospital patients racing for their lives along the beach; the crisis had
come one step nearer. At this moment the doctor went back to the
station ; he could see one side of a hill belching fire, not a quarter of
a mile away; he set his teeth and made for the station and, when he
had ascertained that the place was clear, made a race back to the
boat on the beach, while the ground heaved and swayed beneath him.
At the boat landing another problem confronted him; the sea was
boiling hot, and the boat lay out a little from the beach. Fortunately,
a box was found, and throwing it down at the edge of the water, the
doctor sprang from it into the boat. The native crew pulled with
might and main, but they had only gone a short distance when the
earth reeled with a great thunder, and looking back the doctor
saw the fragments of his house and hospital hurled into the air.
A volcano had burst out in the middle of the hospital grounds, and
from the place where the hospital stood a column of steam was shot
up with such prodigious velocity that in less than a minute it had
risen 20,000 feet above the level of the crater. At this elevation the
particles of finely powdered rock were caught by the prevailing winds
and carried great distances out to sea. A steamer running between
Sydney and Fiji, several hundred miles away from the islands, had
her decks covered with minute particles of volcanic dust. On the
surrounding islands it rained ash and cinders, and vegetation -was
sheathed in a thick layer of sulphurous ash. Besides this a sticky
mud rain fell, a mixture of condensed steam and ejected dust. The
compressed steam rushing at lightning velocity through the main
vent and the fissures in the sides of the crater formed a gigantic
hydro-electrical machine and charged the atmosphere with electricity.
Every few seconds there issued from the murky cloud, which hung
like a pall over the island, flashes of vivid lightning. The French
steamer Pacifique arrived on the scene four days after the eruption
and, owing to the abundance of atmospheric electricity, could not get
its wireless to work.
500 Rev, M. Frater — Volcanic Eruption, Ambrym Island.
About two hours after the outbreak at the Mission Station, the
eruption, still following the same line of weakness, made a further
leap and reached its last stage. Out to sea, at a distance of about
a mile from where the hospital stood, where there was a depth of
25 fathoms of water, a submarine volcano burst out and formed
a crater cone 330 feet high, which was afterwards named ‘‘ Sealark
Hill”’ after the survey ship which was sent by the British Admiralty
to make a survey of the island. The enormous quantities of ‘‘ejecta”
which poured out of this volcano soon formed a connexion with
Ambrym Island and added a considerable area to its extent. On the
abatement of the voleano which swallowed the Mission Station, it
was found that a lagoon, connected with the sea by a narrow channel,
had formed in the crater, covering the entire mission compound.
Over the place where the hospital stood there is a depth of 8 fathoms
of water, and from the soundings made by H.M.S. Sealark it was
ascertained that the lagoon forms a safe, land-locked hurricane
harbour for ships of shallow draught, provided, of course, no other
volcano bursts out. To most mariners, however, the shelter provided
by the crater of a volcano from the violence of a hurricane will look
like a choice between Scylla and Charybdis and, very probably, they
will prefer to take the risk of the element they know best. The
first time an attempt was made to enter the lagoon the mud around
the edge was still boiling and steam was rising from all over the
surface of the water. The sounding line was kept going and at
20 fathoms it dropped into the burning lava where the lead attach-
ment was melted. While the sailors rested on their oars at the
entrance of the lagoon a submarine explosion startled the occupants
of the boat and quenched the desire for further exploration. It was
no place for either men or angels to linger.
The configuration of the surrounding country has entirely changed.
Only by the aid of instruments is it possible to locate the position of
any particular place. Across the extensive valley which lay behind
the hospital a range of hills 500 feet high had been raised. So complete
was the destruction of the hospital and mission buildings that not
even a match was left. Thousands of acres of fertile lands had been
changed to barren wastes, forests were blasted, and large numbers
of lives lost. All the old familiar landmarks on the shore had
disappeared, and the hills in the background were covered with
a thick layer of volcanic dust.
During the night when the hospital staff was watching the
progress of the fire a lava-flow reached the sea about a quarter of
a mile north-east of the hospital. Quite oblivious of their danger they
crossed over to have a look at it. They saw the stream of molten
metal,! like an incandescent avalanche, sweeping everything before
it. Masses of rock and vegetation were borne along on its surface;
it crashed through the big banyan-trees and teakwood giants; the
trees were tossed into the air and rebounded like indiarubber balls.
On the level ground near the coast the stream was travelling at the
rate of four miles per hour, was 200 yards broad, and, on being traced
after the surface of the lava had solidified, was found to have its
' This use of the term is consistent with that by miners and civil engineers.
Rev. M. Frater—Volcanic Eruption, Ambrym Island. 501
source in a fissure eruption in the centre of the island. It is not
easy to describe the kind of cauldron that was formed when this
huge mass of molten metal reached the sea; it plunged into it with
loud detonations; the red-hot lava was shivered like melted glass
into millions of particles; gigantic blisters were formed, exploding
like miniature volcanoes. The crackling noise was deafening, and to
such a height was the column of steam and ash shot up that the
spectators on a neighbouring island, twenty miles away, imagined
that a new volcano had burst out on the sea-shore. The sky was
darkened and, for miles around, the sea was covered with dead fish
and debris of all sorts. Knormous quantities of pumice-stone floated
on the water and covered the sea for miles.
By the time H.M.S. Sealark arrived in the islands the surface of
the lava streams had solidified and it was possible for the Survey
party to trace the flows from the shore to their sources in the interior
of the island. A belt of fracture, marking the line of volcanic
activity which runs through the island, was discovered, and on this
line of weakness all the old and new volcanoes are placed. At the
opposite end of the island, where volcanic action has become almost
extinct, a considerable amount of vapour rises to the surface through
fissures in the ground. From some of the fissures flows water hot
enough for the natives to cook their yams. In their journeys across
the island the natives use these places as camping-grounds where
they can procure hot water without the labour of kindling fires.
But of recent years, due possibly to the exhaustion of volcanic energy
in the south-east part of Ambrym, the number, as well as the heat,
of these hot springsis diminishing. Standing on an elevation near one
of the volcanoes on the ask plain it is possible for the eye to follow
the belt of fracture to the other end of the island, and then with an
intervening channel of ten miles rises the lofty cone of the Lopevi
volcano, indicating that it lay in the same line of weakness on the
earth’s crust.
During the visit of the Survey party, Mount Benbow was in
violent eruption, and presented a beautiful sight. Every few
minutes, and sometimes almost continuously, eruptions took place,
and, with every explosion, gigantic clouds of dust and ash of crebri-
form shape were shot up to a great height. From the anchorage of
H.M.S. Sealark, at the north end of the island, the officers measured
the height of the column and found it to be 12,000 feet above the lip
of the crater.
The mouth of the crater was one mile long and three-quarters of
a mile broad. Standing on the lip of the crater it was possible to
watch operations. With bellowing noise showers of hot stones
were ejected, some of which fell uncomfortably near to members
of the party who approached the danger zone. Blocks of rock,
torn from the walls of the vent, were hurled into the air. The
heavier rocks fell back into the crater, and the smaller and lighter,
carried by the winds, were piled around.the crater with more or less
regularity, according to the direction of the prevailing wind. The
fragmental materials thus accumulated were of all shapes and sizes,
from the finest powdered stone to large blocks blown out of the
502 Rev. M. Frater—Volcanic Eruption, Ambrym Island.
crater walls. Volcanic bombs lay scattered around. They had been
ejected in a pasty condition and readily took the impress of a coin. .
When broken the core was found to be porous, but in the passage
through the air the outside had become rounded and smooth. From
the lip of the crater the inner wall had a sloping dip of 1,000 feet
to an extensive level plateau of what appeared to be boiling mud,
from the centre of which rose another crater cone, which was partly
obscured by vapour rising from the boiling mud as well as from the
innumerable holes in its walls. From the inner crater came the
explosions of steam and ash, but there was no possibility of looking
into its interior.
Eight lava streams, of lengths varying from one to ten miles,
flowed during the eruption. Some proceeded from volcanoes with
crater cones, others from fissure eruptions which were marked by an
absence of crater-shaped vents. The fissure eruptions ejected lava in
larger quantities than the crater volcanoes, though the flow was not
always from the central vent but from rents in the crater wall. So
enormous were the floods of this molten metal that the lava stream
pierced through the thick bush, forming tracks from 100 yards to
three-quarters of a mile broad. Viewed from the sea these black
cindery tracks, running inland through the dense vegetation,
resembled railway cuttings, and the smell of the cooling slag tended
still further to confirm the resemblance. Sometimes, the lava stream
parted and enclosed timber-covered islets. ‘The trees on these islets
survived, like island stations on a railway line. The only trees
which seemed to withstand the first onset of the avalanche were the
giant she-oaks. The molten metal flowed round these forest kings
and clasped them in its embrace. The trunks were slowly consumed
and deep cylindrical holes were left, at the bottom of which could be
seen the glowing red lava. These holes, ranging from 10 to 20 feet
deep, assumed the shape of the tree-trunk, and on the sides of the
encrusted lava could be seen the impress of the tree. The cooling of
the lava must have been very rapid, as the bark of the trees on the
edge of the stream, where there was little depth of fire, was not even
burnt, but only scorched. Here and there on the lava streams were
miniature cones formed by the escape of gas and lava from the
liquid interior, and these cones, some of them 15 feet high, continued
to spout molten lava long after the main stream had passed. Three
months after the eruption, heated vapours were still issuing from these
cones. ‘The vapours, impregnated with iron and sulphur, were acting
chemically on the rocks, and produced a wealth of variegated colours
in which white, yellow, and red predominated. Underneath the
surface of the lava streams there seemed to exist numerous vesicular
cavities in which vapour was imprisoned. The tread of the feet
produced a dull, hollow sound and reverberated like the noise of
a drum. Many fissures and cracks in the stream were still spouting
hot vapours, and in some of the cracks the rocks were glowing within
a few feet of the surface.
The lava streams assumed a variety of structures due to the
amount of aqueous vapour imprisoned. Some were slaggy and ropy
with a smooth, glassy appearance, others of the scoriaceous type had
Grou. MaAc., 1917.
KUALA TEKA
PratE XXX.
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th} Granite sth nk
PARE pt
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actuate
Boulder-
ars
ty
S=Sungei = River
Pulau =/sland
Kuala =Mouth
Lubok =Lynn
Tanjong = ea.dland
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jSANJONG=LINDON
NERS
(UALA JERANSON
JBATU REDAP ®&
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ULU PAHANG
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E. 8. Willbourn—The Pahang Volcanic Series. 5038
a rough and cindery appearance. The resemblance between the
slag heap of an ironwork and the natural lava is very striking.
Indeed, to stand on a lava-flow with the eyes shut by the side of
a steam blow-hole and with the smell of the molten metal in the
nostrils, it does not require a great exercise of the imagination to
transplant oneself from the voleanoes of the South Sea Islands to the
ironworks in the Black Country of Great Britain. Travelling over
the rugged, cindery flows was attended with difficulty and danger,
and the jagged edges made progress slow.
A strange phenomenon was witnessed in one of the volcanoes.
After belching molten metal for two weeks, its activity gradually
subsided, and apparently, from out the same vent, torrents of ice-
cold water began to flow. The same phenomenon was witnessed by
an old French settler in a volcanic outburst twenty years previously.
From the other volcanoes abundant streams of moderately cold water
gushed out and occasioned no surprise, but ice-cold water and molten
metal from the same fountain seemed strange and incongruous. ‘The
floods of ice-cold water followed the same course as the lava-flow,
covering the lava with a thick layer of silt and ash. A good path
was formed, rendering this lava track the easiest of all the streams to
traverse. Following its course it is possible to trace the lava from
the sea to its place of origin at the edge of the ash plain.
The phenomena presented by the Ambrym eruptions would seem to
indicate that water played as important a part in fissure eruptions,
where intermittent explosions of steam were absent, as in the violent
eruptions from a crater cone where explosions of steam were present.
Eight lava streams were formed during the eruption; some of them
had their source in .overflows of lava from crater vents amid
paroxysmal explosions of steam, others welled out of the earth like
a fountain without the formation of crater cones and without explosions
of steam. But the presence of water was as marked in the one case
as in the other. In the fissure eruption which took place near the
village of Meltungan streams of lava literally gushed out of the
fissures without intermittent explosions of steam. These fissures
were characterized by an entire absence of volcanic cones and extruded
a continuous stream of molten lava which flowed for miles until it
reached the sea. The lavas from these flows were impregnated with
as much aqueous vapour as the lavas from crater eruptions. From
other islands, 15 to 20 miles away, these lava streams could be traced
by the columns of steam which rose from the cooling metal."
TV.—TuHe Pawane Votcanic Serizs.
By E. S. WILLBOURN, B.A., Assistant Geologist, Federated Malay States.
(WITH A MAP, PLATE XXX.)
(Concluded from the October Number, p. 462.)
Descrretion oF Turrs anp Breccras oF THE Panane Voncanic SERIES.
Y far the greater part of the volcanic rocks of Malaya consists of
fragmental deposits, which at first sight seem to be andesite-
tuffs and andesite-breccias, for most of them contain abundant
' Dr. Gregory’s description of the Ambrym eruptions will appear in the
December Number.
504 #. S. Willbourn—The Pahang Volcanic Series—
fragments of andesitic lava. However, the majority also contain
numerous fragments of quartz, some of which occur as isolated
angular grains in the cement, others embedded in a very fine-grained
siliceous rock, and sometimes showing rounded outlines and even
bays, invaded by the siliceousaggregate. Tuffs which occur in certain
localities, e.g. at Kuala Tekal, Tembeling, and Sibah near Kuala
Lipis on the Pahang railway, contain the usual fragments of
andesite-lava, with numerous fragments of quartz like those just
described, and in addition fragments of rhyolite-lava or quartz-
porphyry. It is probable that the great majority of the Pahang
Voleanic Series of tuffs are formed of an admixture of andesitic,
rhyolitic, and sedimentary material.
The first type to be described is an andesite-rhyolite-breccia’
from the Benta—Kuantan road, at the 47th mile from Benta. There
is no hand-specimen of this rock in the collection, but judging from
the slide (Pl. XXIX,’ Fig. 4) it is a dark-green rock, fairly fine-
grained, with occasional red spots, made up of abundant fragments of
andesite-lava and quartz, with occasional crystals of felspar and
fragments of quartzite, set in a cement of quartz and calcite. In
addition there are numerous pieces of altered rock, consisting of a fine-
grained siliceous aggregate with large included quartz grains, and in
one case enclosing a rectangular pseudomorph of magnetite, probably
after felspar. Also there are some fragments of a highly altered
rock, composed of a rather coarser quartz mosaic, with a little black
iron-ore evenly distributed throughout the mass, and comparatively
large irregular flakes of white mica.
The andesite-lava fragments are made up of felspar laths, usually
untwinned and with a low extinction angle, set in a dark-green
isotropic material which often includes large grains of magnetite.
There is a greater quantity of glass in these lava fragments than in
any of the andesite-lavas which have been noticed in situ. The
felspar laths are bent, suggesting that the andesite fragments were
hot plastic masses when they were detached from the parent body.
Some of the lava fragments contain numerous cavities filled with
a green chloritic mineral which is arranged in radiating fibres.
The quartz grains vary considerably in size and appearance, some
being angular while others are rounded and have a corroded
appearance. The quartzite fragments are stained red with hematite,
and magnetite and hematite are widespread, both in the lava
fragments and in the cement. The few felspar crystals which are
contained in the tuff are usually broken, and in composition correspond
to oligoclase-andesine.
Breccias similar to this occur outside Pahang in the south of
Negri Sembilan ** and north of Johore*, but the rhyolite admixture
cannot here be recognized definitely, and the numerous angular
1 Described by Mr. Scrivenor in The Geology and Mining Industries of
Ulu Pahang, Kuala Lumpur, 1911, p. 43, No. 1851, pl. xi.
? Plate XXIX of rock-sections, also explanation, appeared with the earlier
part of this paper in the October Number, facing p. 462. h
3 An asterisk marks the names of all those places in Malaya mentioned
in the text which are outside the area shown on the accompanying Map,
Plate XXX.
Federated Malay States. 505
quartz grains may be shattered fragments from the volcanic neck.
They are probably not a sandy admixture brought down by streams,
for the fragmental volcanic rocks of this district are interstratified
with a series of shales which were at one time calcareous, and from
which sandy beds are typically absent.
A volcanic breccia was found occurring as boulders at Kuala Seli*
in Selangor at the 133 mile from Kuala Lumpur on the road to
Ginting Bidei (not shown on map), and reference has already been
made to the rock as perhaps revealing the age of the purple quartz-
porphyry which is found as boulders on the Main Range between
Kuala Lumpur and Bentong.
It is green in colour and is made up of angular fragments of the
following rocks; quartz-porphyry something like that occurring in
situ at Jeram Gading* and as boulders in this district and on Ginting
Sempak *, quartzite, and small rounded pieces of a homogeneous
fine-grained siliceous rock like those which occur in the felspathic
grits that are so often associated with cherts. They may be of
sedimentary origin or they may be devitrified lava. here are
pseudomorphs of epidote and an opaque dust which have a wavy
‘outline, and in form resemble the altered biotite crystals in the
Ginting Sempak quartz-porphyry. In addition grains of quartz make
up a considerable part of the rock, some of them angular, others
having a rounded corroded appearance, and broken crystals of
orthoclase and oligoclase-andesine felspar are also common. There
is very little fine-grained material, but amongst it can be noticed
some grains of secondary epidote.
About half a mile west of Tembeling a deposit of andesite-rhyolite-
breccia is exposed in the railway-cutting which is probably near
a volcanic neck, for it is a coarse-grained red rock, the fragments
being often more than an inch across, and consisting of quartzite,
limestone, lava (both andesite and rhyolite), and crystals of felspar,
quartz, and occasionally augite, the cement being quartz-aggregate,
calcite, and iron-ores.
The andesite-lava fragments are well preserved, and belong to the
type with a ground-mass of very small microliths of felspar enclosing
well-shaped augites partly altered to chlorite, calcite and magnetite,
and biotite crystals which have been bleached and have sometimes
been entirely obliterated by secondary iron-ores. The rhyolite
fragments are much more altered, the ground-mass now consisting
of a secondary aggregate of quartz in which round bodies which were
originally spherulites can occasionally be distinguished under crossed
nicols. The shape of the lava fragments is very irregular, but there
is no sign of a rapidly cooled margin. These lava fragments are
distinct in character from the deposits of boulders in tuff which will
be described later, the principal point of difference being that they
are not water-worn.
Another slightly different type exposed in the railway-cuttings
near Kuala Tekal may be described as an andesite-rhyolite-tuff, and
in the hand-specimen it is a dark-green rock containing small black
lava fragments, and crystals of felspar, quartz, and biotite, varying
up to cm. across.
506 EH. S. Willbourn—The Pahang Volcanic Serres—
Under the microscope the lava fragments are seen to be of two
varieties, one made up entirely of felspar laths with trachytic
structure, the other being very fine-grained and containing spherulites.
The felspar crystals also are of two varieties—oligoclase-andesine
and orthoclase. There is a good deal of dark-green chloritic material
spread throughout the rock.
A similar rock at Sibah near Kuala Lipis contains a good deal of
secondary epidote and mica, some of which has been formed by the
alteration of augite crystals. No augite is left unaltered, but the
sharply defined octagonal outline of the pseudomorphs suggests that
augite was the original mineral.
Andesite tuffs without considerable admixture of more acid
material are rare, but a specimen of greenstone with abundant
epidote collected on the Benta—Kuantan road near the main Gondwana
outcrop east of the Pahang River is more basic than those hitherto
described, and contains little, if any, rhyolite material. Thefragments
of andesite-lava contain small augites as granules interstitial to the
felspar laths. Crystals of oligoclase-andesine and augite are common,
and there are a few fragments of quartz which are penetrated by
epidote, and which when viewed between crossed nicols look hke
fragments of granophyre in which the felspar has been replaced by
epidote. Fragments of an altered shaly sedimentary rock occur,
and so do occasional rounded grains of corundum. Magnetiteis very
abundant in this rock, most of it being secondary.
Besides the above types, consisting in the main of fragments with
very little fine-grained matrix, there is the compact type of tuff, in
which the bulk of the rock is made up of a very fine-grained material,
now of a siliceous nature.
Such deposits can only be determined as volcanic when a con-
siderable number of the larger fragments are of felspar or, as only
rarely happens, when fragments of lava can be recognized; in fact,
there is an insensible gradation into a sedimentary grit. Probably
many rhyolite tuffs are of this nature, and cannot be distinguished
from felspathic grits. Then, again, other rocks very much resemble
rhyolite tuffs, but they cannot be distinguished from partly altered
rhyolite-lava flows unless some field evidence is forthcoming.
Deposits oF Boutprers 1n TurFF.
A most remarkable deposit is found in Pahang associated with
tuffs and breccias similar to those already described. It consists of
rounded masses of lava, tuff, acid intrusive rocks, or sedimentary
rocks embedded in a fragmental matrix, the masses being very
different from bombs and lapilli which are usually associated with
tuffs. In several of the known exposures the boulder-in-tuff deposit
passes into the usual tuff without boulders or pebbles.
Their characteristics are summed up as follows :—
1. They vary in size from a pea to over a yard across (at Kuala
Tekal).
2. They are water-worn, show no sign of vesicular structure, and
have not a glassy margin.
OT Vie
Federated Malay States. 507
3. They are sometimes arranged in definite strata where they
occur as pebbles of small size, e.g. at Tanjong Lindong.
4. In composition they coincide with the Pahang Volcanic Series
rocks found in situ, including andesite-lava, rhyolite-lava, andesite-
rhyolite tuffs and breccias, quartz-porphyry, and granophyre. No
dolerite boulders have yet been found in these deposits. In addition to
these volcanic rocks, one boulder of reticulating quartz veins was found
in the Kuala Tekal section, and at Batu Redap many of the pebbles
consist of a rock which should be described as a slightly felspathic
erit—though it may be a fine-grained rhyolite-tuff. There is no
distinction between the mode of occurrence of the sedimentary rock
and the vein-quartz as boulders in the tuff, and the much more
numerous boulders of igneous rocks.
The table on p. 508 gives the different localities in which the
boulder deposits are found and the nature of the boulders.
Some of the boulders in tuff at Pulau Guai (see Map, Plate XXX)
are of a rhyolite with numerous dark angular shale-inclusions, some
of which contain crystals of chiastolite. This rock contains a good
deal of calcite mixed with it.
It is very like a rhyolite-lava with shale-inclusions which occurs
in situ at Pulau Chengai. Unfortunately, in the field the Pulau
Chengai rock was mistaken for a conglomerate belonging to the |
Gondwana series, and certain other exposures near here which were
named as coarse-grained quartzites may be really this same rhyolite-
lava with inclusions of shale, so nothing can be said with certainty
as to whether the boulder deposits of Pulau Chengai occur near the
boundary of the Gondwanas and Raubs. This cannot be taken as
evidence, but it will be seen from the third column of the following
table that there is evidence to show that the boulder deposits occur
always at a boundary of an outcrop of Gondwana rocks with Raub
rocks.
The tentative theory as to their origin,’ put forward by
Mr. Scrivenor, the Government Geologist, was ‘‘ that they were
derived from already consolidated sheets of lava and ash, and masses
of igneous rock consolidated below the surface, and that they became
rounded by attrition in some way we cannot explain before they
were shot up into the sea and fell back on ash being deposited on
the sea-bottom ’’.
Owing to the infrequency of exposures the field relationships of
the deposit are very little known, but, in the nine districts where the
deposit has been examined, the small amount of evidence that can be
collected indicates that the deposit lies at the junction of Raub and
Gondwana rocks. It is probable that there was an important
unconformity between the Raub Series and the deposition of the
Gondwana rocks, and evidence for this is afforded by the occurrence
- of pebbles of veined chert and Pahang Volcanic Series rocks in the
Gondwana conglomerates. It seems likely that the pebbles were
derived from cherts and Pahang Volcanic Series rocks of Raub age,
and the fact that sufficient time elapsed after the formation of the
1 The Geology and Mining Industries of Ulu Pahang, Kuala Lumpur, 1911,
p. 47.
\
i ve
508 E#.S. Willbourn—The Pahang Volcanic Series—
No. LOCALITY.
NATURE OF
BOULDERS.
1. Near Kuala Tekai,
Tembeling River.
2. Pulau Guai
(Pahang River).
Tuffs andesite.
Quartz-porphyry (?).
REMARKS AS TO ASSOCIATED
ROCKS, ETC.
Country rock is Gondwana quartzites,
etc., yet the boulder deposits contain
much ¢alcite.
Rhyolite - andesite -
tuff. Rhyolite-lava,
andesite - lava.
Quartz - porphyry
and porphyrite.
3. 1143 mile, railway.
Much weathered, no
specimens collected.
Up-stream from here the nearest sedi-
mentary rock in situ is Gondwana
quartzite 14 miles away.
Quartzite near 115th mile. Exposures
too much weathered at and near
1143 mile to say whether Raubs or
Gondwanas.
4. Tanjong Lindong
to Pulau Prias
(Pahang River).
5. 105th mile, railway.
Rhyolite, andesite, | An outcrop of Gondwana quartzite
and perhaps quartz- | occurs near Bulau Prias.
porphyry.
Andesite, trachyte, | At boundary of Gondwanas and Raubs.
rhyolite or quartz-| Granophyre is in situ in Raub Series
porphyry, gyrano-| rocks within 3 miles of this place.
phyre.
6. Kuala
to Lubok Plang
(Pahang River).
Jeransong
Rhyolite and perhaps
quartz-porphyry.
Chert is interstratified with the tuffs
at Lubok Plang, also rhyolite-lava
flows. The surrounding country
rocks are Raubs.
7. Batu Redap
(Pahang River).
Felspathic grits, per-
haps voleanic.
The railway is within a mile or so and
core-boulders of quartzite are lying
on limestone, so there may be a
junction of Gondwanas and Raubs
near here.
8. Pulau Chengai
(Chengali),
Pahang River.
Rhyolite and perhaps
rhyolite-tuff.
Probably near boundary of Gondwana
and Raub rocks.
9. Kuala Tekal, 87th
mile, railway.
Rhyolite quartz-por-
phyry, and porphy-
rite.
Cuttings too much weathered to deter-
mine whether the sedimentary rocks
belong to the Raub Series or whether
they are Gondwanas.
ae = 2
eee
Federated Malay States. 509
Raub cherts for them to undergo veining before being eroded shows
that the unconformity was an important one. This theory was
explained in full in 1911 by Mr. Scrivenor,' but at that time if was
thought that the chert beds formed a single separate series between
the Raub and Gondwana rocks, whereas it is now known that many
of the chert beds of the Peninsula are interstratified with Gondwana
quartzites.
If the deposits of boulders and pebbles in tuff occur at the boundary
of Raub and Gondwana rocks, it is fairly clear that they were formed
during the period between them, i.e. in the period of terrestrial
conditions.
Mr. Scrivenor said in 1911, that they bear resemblance to the
‘Cashy conglomerate ’’ of the Mendips, described by Professor S. H.
Reynolds,? but added that after examining Mr. Scrivenor’s photograph
of the Pulau Guai beds (plate ix, Ulu Pahang memoir) Professor
Reynolds thought that the two deposits do not agree. The bedding
observed in the Pahang deposits is a point of difference from the
Mendip ‘‘ashy conglomerate”. Professor Reynolds gives four
possibilities as to the nature and origin of the Mendip deposit, and
one of them, slightly amended, is now suggested as accounting for
the Pahang deposit.
The deposit of boulders and pebbles in tuff was laid down during
the latter part of the unconformity which followed the Raub period,
and during the subsidence when the Gondwana rocks were formed.
The line from Kuala Tekai on the River Tembeling to Kuala Tekal
on the River Pahang marks the position of the coastline during
a pause in the depression, in which beach deposits were formed
in sheltered parts of the coastline, and were mixed with volcanic
ash which all this time was being deposited on the sea-floor by
active volcanoes. Sufficient time must have elapsed between the
beginning of the terrestrial conditions and the end of the period of
formation of the beach-deposit to allow for the denudation of the
considerable thickness of sedimentary rocks which must have covered
the quartz-porphyry, granophyre, and other intrusions, for boulders
of these intrusive rocks are common in the beach-deposit.
This theory explains the heterogeneous nature of the boulders and
pebbles and their well-rounded appearance. It also explains the
bedded nature of the deposit and its association at Lubok Plang
with a band of chert, for it has been suggested before that chert can
be formed in shallow water if the growth of Radiolaria is favoured
by abundant silicates being supplied to the sea-water*® by gases from
’ 1 The Geology and Mining Industries of Ulu Pahang, Kuala Lumpur, 1911,
p. 56.
2 Quart. Journ. Geol. Soc., vol. lxiii, p. 227.
3 J. B. Scrivenor, ‘‘ Radiolarian-bearing Rocks in the East Indies’’: GEOL.
MaG., Dec. V, Vol. IX, No. VI, June, 1912, pp. 241-8. Mr. Scrivenor
discusses the origin of the Peninsula chert, and points out that in Kedah the
chert is not associated with volcanic rocks.” He suggests that large quantities
of silica in solution, supplied by tropical weathering of siliceous rocks, may
have promoted, or helped to promote, the abundant growth of Radiolaria in
Shallow seas.
510 E.S. Willbourn—The Pahang Volcanic Series—
voleanic effusions.’ The absence of any great quantity of sedimentary
material can readily be understood, as also the fact that the boulder-
in-tuff deposit often passes into a tuff devoid of pebbly material.
The theory that the boulders were deposited in water near a shore-
line helps to explain a peculiar circumstance noticed with regard to
the tuffs near Pulau Guai. ‘There is a series ef exposures of
granophyre over a distance of 4 miles to the north of Pulau Guai,
one occurring only about a hundred yards up-stream from the first
boulder deposit, and all the tuffs between Pulau Guai and Kuala
Tembeling contain fragments of granophyre, whilst of the many
specimens of tuffs examined from Pulau Guai only one contained
what might be regarded as a fragment of granophyre. At the
102nd mile on the railway there is an intrusion of granophyre, while
3 miles further north is a boulder deposit in tuff. One of the
boulders consists of granophyre, and fragments of granophyre occur
in the tuff at the 105th mile and in tuffs between there and the
intrusion.
The granophyre was exposed by the action of denudation during
the period of unconformity, and fragments of it were carried down
by stream action and deposited with tuffs which were being formed .
by active volcanoes at the time. Evidently the shore-line moved
from west to east or a little north of west to a little south of east,
and this explains the change from tuffs with granophyre fragments
to tufis without granophyre fragments when going down-stream at
Pulau Guai, for as soon as the outcrop of granophyre became sub-
merged below low-tide mark it would no longer be subject to
denudation.
It was hoped to include in this paper a comparison of the Pahang
Volcanic Series with the older volcanic rocks of the Malay Archi-
pelago, as described in various Dutch and German publications, but
the process of translation has proved so laborious and slow that it
has not been possible to compare them with the volcanic rocks of any
other districts but the Goemaigebergte of South Sumatra, which are
described by Dr. Emil Gutzwiller in Mijnwezen, 1912, Verhandelingen.
Comparison OF THE PananG Votcanic SERIES WITH THE PERMO-
CarBonIFEROUS Votcanic Rocks oF THE GoEMAIGEBERGTE, SoUTH
SUMATRA. ;
There are no older acid intrusive rocks in Sumatra which correspond
to the quartz-porphyries and granophyres of Pahang, nor are there
any rhyolitic lavas or trachytes.
Dolerites.
Those rocks of the Goemaigebergte which typically have an
ophitie structure are divided by Dr. Emil Gutzwiller into two groups,
the diabase-porphyrites and the diabases; the former group containing
no olivine or diallage, while the second group usually contain one or
other of them.
Very few specimens of dolerite of the period of the Pahang
Volcanic Series have been collected in Pahang, so a detailed comparison
1 EH. E. L. Dixon, Quart. Journ. Geol. Soc., vol. lxvii, pp. 511-31, 1911.
Federated Malay States. Dill
of the specimens in the two countries would be without value, but
one difference is sufficiently clear, namely that the felspar of the
Pahang Voleanic Series dolerites is very much more acid in character,
varying, in the five or six specimens examined, from oligoclase with
an extinction angle of 12° to andesine. As already mentioned in
the detailed description of the Pahang Volcanic Series dolerites, one
of them contains quartz which is probably original. The alteration
of the augite in both series results either in the formation of chlorite
or of an amphibole. None of the dolerites collected from the Pahang
Volcanic Series contain either diallage or olivine.
Andesites.
Dr. Emil Gutzwiller follows the custom of the Continental
petrologists in using the name porphyrite for the older andesitic
lavas.
Judging by the descriptions of the ten Goemaigebergte porphyrites
given in Mijnwezen, 1912, the most obvious difference is in colour,
for none of the porphyrites of South Sumatra have the red-brown
colour which is so typical of many of the Pahang Volcanic Series
andesites. A more important difference is in the composition of the
felspar, for only two specimens out of the ten contain oligoclase-
andesine, the remainder having felspars varying from andesine-
labradorite (three specimens), through labradorite (two specimens),
to bytownite (two specimens) and anorthite (one specimen), whereas
the felspar of the Pahang Volcanic Series andesites on the other
hand is never more basic than andesine.
The mode of alteration of the felspars in both the Pahang Volcanic
Series and the Sumatran andesites is occasionally the same, then
resulting in both cases in the formation of chlorite, but usually there
is a considerable difference in the products of alteration of the two
series, which is to be expected after considering that, apart from
occasional specimens, the composition of the felspars in the two
series 1s so widely different. In many of the Pahang Volcanic Series
rocks the alteration product isa brown, opaque, extremely fine-grained
material, which is probably kaolin, often associated with tiny flakes
of secondary mica, not a common mode of alteration for the felspar
of the Sumatran rocks. On the other hand, the felspar of the
Sumatran rocks is often altered with the separation of epidote and
calcite (saussurite). The oligoclase-andesine felspar of one of the
Tembeling andesites contains a good deal of epidote, but in most of
the Pahang Volcanic Series rocks the epidote which they contain
has not been formed from the felspar. These rocks usually contain
calcite, sometimes formed by alteration of the felspar, but often
simply added to the rock by infiltration from neighbouring calcareous
sediments.
The porphyrites of South Sumatra are divided petrologically into
two groups, the labradorite-porphyrites and the augite-porphyrites,
the first group containing no phenocrysts of pyroxene, but in some
cases (Nos. 7, 8, and 9 Gloegoer) chlorite aggregates occur which are
undoubtedly secondary after amphibole or pyroxene. In some of
these, augite grains occur unaltered in the groundmass. A similar
512 EH. S. Willbourn—The Pahang Volcanic Series— —
division of the Pahang Volcanic Series andesites into those with
and those without augite could be made, but, as already mentioned,
it is quite possible that all the andesites originally contained augite,
which in some cases has been weathered to chlorite. The shape of
the chlorite aggregates in some of the lavas confirms this idea, but
in others chlorite occurs only as irregular areas in the groundmass,
and there is no confirmatory evidence as to its origin.
Titanite is an alteration product common in the Sumatran rocks,
whereas it was seen in only one of andesites of Pahang; some of the
Sumatran augite-porphyrites are uralitized, and titanite occurs as
a secondary product formed during this change. Another point of
difference is that some of the Pahang Volcanic Series andesites
contain olivine, whereas none occurs in the Sumatran porphyrites.
Apart from the differences mentioned above, the andesites of the
two series bear a certain resemblance one to the other. Both are
practically always holocrystalline with plagioclase felspar making up
the greater part of the rocks as phenocrysts and groundmass, the
latter containing little or no glassy base. Apatite is widespread in
small quantities in all the Pahang Volcanic Series and Sumatran
andesites, and a colourless augite with its alteration products are also
widely distributed. Rhombic pyroxene is always absent.
Serpentine.
Serpentine and peridotites are found in many of the islands of the
Dutch East Indies, including Java, Borneo, the Moluccas, and the
west coast of Sumatra. Dr. Verbeek writes a description of all these
occurrences in Diynwezen, Wetenschappelijk gedeelte, 1905, and from
this it appears that the serpentine in all these places was derived
from olivine. Most of the serpentine outcrops in the Peninsula show
no traces of the original rock, but occasionally, as in Negri Sembilan,
remnants of amphibole suggest that the serpentine owes its origin to
that mineral. An outcrop in the Perak River, however, resembles
serpentine of the islands of the Archipelago in containing remnants
of olivine.
Tuffs and Brecevas.
They differ in much the same way as do the Sumatran lavas from
the Pahang Volcanic Series lavas. The andesitic constituents are
similar, except in the composition of the felspars, but no simultaneous
effusion of rhyolite material took place in Sumatra, and so the
Sumatran fragmental rocks differ from those of Malaya in that the
tuffs are of an unmixed andesitic composition. The same difference
applies to the breccias of the two areas. There is nothing similar to
the remarkable deposits of boulders in tuff in the Sumatran area.
The age of the Sumatran volcanic rocks is given by Verbeek?
as youngest Paleozoic, while Volz? gives them a pre-Triassic
* R. D. M. Verbeek, ‘‘Top. En. geol. beschrijving van een gedeelte van
Sumatra’s West Kust’’: Batavia Landsdrukkerij, 1883, p. 270.
2 W. Volz, ‘‘ Zur Geologie von Sumatra’’: Geol. und paliontol. Abhand-
lungen herausgegeben von E. Koken, Neue Folge, Bd. vi, Hit. ii, pp. 87 ff.,
Jena, 1904.
“
2 i. ae
Federated Malay States. 513
age, and on account of this Dr. Aug. Tobler, in his description of the
volcanic rocks of South Sumatra in Mijnwezen, 1912, assigns them to
the Permo-Carboniferous period. Thus, in age the Sumatran and
Malayan volcanic rocks correspond, for the latter are extensively
interstratified with Raub rocks, and certain fossils from limestone
beds belonging to the Raub Series give it a Permo-Carboniferous age.
Volz says that the volcanic rocks of South Sumatra do not persist
so late as the Triassic period, and this is a point of difference from
the Malayan rocks, for the latter were being deposited during and
probably later than the period of formation of the Lower Gondwana
beds of Pahang, which are correlated with the uppermost Trias.
The Tertiary voleanic rocks of the Goemaigebergte seem, from
Dr. Gutzwiller’s descriptions, to contain no epidote, and this agrees
with the rocks of the Malay Peninsula, where rocks younger than
the Mesozoic granite contain no epidote. It will be remembered
that some specimens of the dark-purple quartz-porphyry of Selangor
contain epidote, and that this is taken as evidence of the pre-Granitic
age of the intrusion.
ConcLUSIONS.
It is not possible to define the limits of the volcanic period with
any certainty. he majority of the tuffs and lavas are interstratified
with Raub shales, and fossil evidence proves that some of them are
of Permian age. ‘The field evidence suggests that the Raub shales
are contemporaneous with the Raub limestones, and the latter
contain fossils of Upper Carboniferous Limestone ( Visean age), but no
volcanic rocks have yet been seen that were underlain and overlain
by Raub limestones. A boulder-in-tuff deposit was seen in contact
with a vertical face of limestone in the river bank a few hundred
yards down-stream from Lubok Plang, but according to the theory
that the boulders are a beach-deposit it is certain that the deposit is
lying unconformably against the limestone. So we have proof that
_ there was volcanic activity during the Permian period (late Raub),
and there is no proof that it started so early as the Carboniferous
eriod.
i It is possible that volcanic activity continued during the period of
dry land which prevailed through the greater part of the Triassic
and perhaps during a part of the Permian period, and we know that
tuffs were being deposited at the coming on of the Gondwana shallow-
water conditions, when the beach-deposit was formed.
Tuffs and lavas were extruded during the deposition of the earliest
Gondwana rocks in the north and south zone now marked by the
Pahang and Tembeling Rivers and probably also further to the east,
though this last point has not been investigated. No cases of Pahang
Voleanic Series intrusions penetrating Gondwana rocks have been
noticed, though there are several doubtful cases; for instance, the
granophyre north of Pulau Guai and the quartz-porphyry at Jeram
Gading*. However, if the beach-deposit of boulders in tuff was
formed immediately before the earliest Gondwana rocks of the
locality it is clear that the granophyre was intruded and laid bare
before this date, for granophyre boulders are included in the deposit.
DECADE VI.—VOL. IV.—NO. XI. 33
OS) ae
514 Notices of Memoirs—Swiney Lectwres on Geology.
Rhyolite-lavas were extruded during the Raub period, and
apparently eruptions of acid rocks and andesites occurred alternately.
There is no evidence that rhyolites were extruded as lavas later than
the Raub period, but eruptions of .andesitic composition took place
during the formation of both the Raub and Gondwana rocks, and as
the eruptions were in full activity during the formation of the
earliest Gondwana beds it is possible that they persisted through the
period of dry land.
All the Raub volcanic rocks that have been examined were
evidently deposited under the sea, and such was the case too with
the Gondwana volcanic rocks, though in the latter case it is quite
probable that for some time the volcanic vents continued to be above
sea-level. adiolarian cherts are associated with Pahang Volcanic
Series rocks at Lubok Plang and on the Main Range in Lower
Selangor*, and it is possible that the silica in the sea-water necessary
for the building up of Radiolarian tests was supplied by pneumato-
lytic emanations from these eruptions. However, no proof of extensive
albitization of the Pahang Volcanic Series rocks is available, and this
is a serious drawback to the theory that the two rocks are related in
origin.
The only intrusion of dolerite that was seen on the Pahang
Railway was in a weathered railway cutting near the boundary of
Gondwanas and Raubs, and it was uncertain whether or not it
penetrated Gondwana rocks. There is no proof whether the dolerite
is of Raub or Gondwana age. The absence of dolerite boulders from
the beach-deposit can be explained by the scarcity of the dolerite
outcrops, and does not prove anything about the age of the
intrusions.
NOTICHS OF MEMOTRS.-
I.—Swiney Lecrvures on Geotoey.!
A course of twelve lectures? on ‘‘The Mineral Resources of the
British Empire’’ will be delivered by Dr. John S. Flett, F.R.S., at
the Royal Society of Arts, 18 and 19 John Street, Adelphi, W.C.
SYLLABUS.
Lecture I. Tuesday, November 13. Inrropucrory.—The mineral
industries in peace and war. Relation of mineral production to
Colonial development. Distribution of minerals of economic value
in the British Empire. Trade between Britain and Colonies in
minerals, metals, etc., in normal times. Effect of war on mineral
production and distribution in the Empire. Statistics of British
Imperial production. Resources of the Empire in minerals.
1 With the sanction of the Trustees of the British Museum (Natural History).
2 The lectures will be given on Tuesdays, Thursdays, and Fridays at
5.30 p.m., beginning Tuesday, November 13, and ending Friday, December 7,
1917. Tobe illustrated by lantern slides. Admission free.
Notices of Memoirs—Swiney Lectwres on Geology. 515
II. Thursday, November 15. Gorp.—World’s production of gold
at different dates. History of gold-mining in Great Britain. Gold-
mining in early times in India, Africa, ete. Discovery of gold in
Australia: history and present condition of gold-mining in Australian
States. South African goldfields: Transvaal, Rhodesia, etc. Gold-
mining in India, Canada, British Guiana, New Zealand, ete.
III. Friday, November 16. Sitver, Prarryum.—Sources of silver
and nature of silver ores. Extraction of silver from lead ores. Silver
production of Great Britain. Canadian silver-mines and the history _
of their development. Australasian silver-mines, especially Broken
Hill. Platinum deposits of British Columbia.
IV. Tuesday, November 20. Iron.—Occurrence of iron ores and
their origin. Production of iron in Britain and the Empire. Iron-
ore deposits of Great Britain. British imports of iron ore and their
sources. Jron-ore deposits of Canada and of the Australian States.
Tron-ore deposits of South Africa.
V. Yhursday, November 22. Coat.—Origin of coal and nature of
the different varieties. Properties and utilization of coal. Coal-
production of the Empire. Exports and imports of coal. British
coal-fields and their resources.
VI. Friday, November 23. Coat (continued). —Coal-fields of
Canada: their production and reserves. Coal-fields of India. Coal-
fields of South Africa, Rhodesia, Nigeria. The coal deposits of the
Australian States.
VII. Tuesday, November 27. O1z.—Sources of mineral oil:
their method of origin and mode of occurrence. History- of oil
industry and world’s production of oil. Oil shales of Scotland,
Australia, and Canada: their treatment and their products.
VIII. Thursday, November 29. Orn (continued).—Oil and pitch
in Trinidad. Oil and gas wells of Canada. Oil-fields of Egypt,
Burmah, New Zealand, Persia. History of mineral oil and geology
of the oil-fields.
IX. Friday, November 30. Sarr, PHospHares, SuLpHUR, ETC.—
Deposits of rock salt in Britain, Canada, India, ete. Mineral
phosphates in British possessions. Sulphur and pyrites: their
distribution and uses. Asbestos mines of Canada, Africa, ete.
Graphite of Ceylon. Nickel and cobalt in Canada.
X. Tuesday, December 4. Copprrr, Tin, Tunesten, etc.—Copper
and tin mining in Britain. Copper production in Canada, Africa,
New Zealand. Tin-mining in the Malay States. Tungsten: the
sources of supply in the British Empire. Molybdenum.
XI. Thursday, December 6. Leap, Zinc, Maneanesr, ETC.—
British lead-mining, past and present. Sources of lead and zine for
British industries. Zinc-lead ores of Australasia. Canadian lead
and zine deposits. Manganese ores of India. Antimony.
XII. Friday, December 7. Diamonps anD oTHER PxEcIoUS
Stones.—Indian diamond production. The diamond fields of South
Africa and South-West Africa: their geology and history. Australian
diamonds. British Guiana. The Burman ruby deposits. Precious
stones of Ceylon. Queensland opals and sapphires.
516 Notices of Memoirs—A Paleocene Bat.
II.—A Paxzocenr Bar. By W. D. Marruew. Bull. Amer. Mus.
Nat. Hist., vol. xxxvii, pp. 569-71, September, 1917.
Ree with well-developed wings are already known from the
Upper Eocene of Europe. A highly specialized skull of a bat
has now been found in the still older Basal Eocene (Wasatch
formation) of Colorado, U.S.A. According to Dr. Matthew, this
specimen represents a new genus and species of the family Phyllo-
stomatide, which still exists in tropical America. It has an
unusually slender snout and a comparatively small canine tooth.
Il I.—Hovrsos anormates pE Lrama xy pr Conpor. By Cayerano
Marrinort. Physis (Buenos Aires), vol. ii, pp. 69-74, 1917.
ALAHZONTOLOGISTS have long been interested in rare cases of
three-toed horses, which recall the condition of the foot in the
Miocene and Pliocene Equide. Martinoli now describes and figures
an analogous case of polydactyly in a llama (Auchenia lama). As
shown by his figure, the abnormal metacarpus consists of four well-
defined bones fused together, and all probably bore phalanges.
IV.—Tae Arperrecta Fauna Locarep 1n tHE MIppLE CAMBRIAN OF
British Conrumpia and Axserta. By Lancasrer D. Burwine.
American Journ. Science, vol. xlii, pp. 469-72, 1916.
\HE Albertella fauna has hitherto been regarded as Lower
Cambrian, but certain new facts of stratigraphy are mentioned
in this paper to prove its Middle Cambrian age. Text-figures are
given of Albertella boswortht,, Walcott (British Columbia), and
A. helena, Walcott (Montana and British Columbia).
REVIEW S-
I.—Fossir Puants; a TrExtT-Book FOR STUDENTS OF BoraNny AND —
Grotoey. By A. C. Szwarp, M.A., F.R.S. Vol. ILL: Pterido-
sperme, Cycadofilices, Cordaitales, Cycadophyta. 8vo; pp. xviii,
656, with frontispiece and 253 text-figures. Cambridge University
Press, 1917. Price 18s. net.
ROFESSOR SEWARD’S book is a continuation of his systematic
account of fossil plants, taken up from the end of vol. i1, which
appeared in 1910. The author was so rash as to make certain
statements in his preface to the previous volume as to the scope and
time of appearance of the remaining portion of his work. Hence the
explanation in the preface of vol. iii that the promised account of
the geographical distribution of plants at different stages in the
history of the earth has been crowded out of vol. i1i and the following
vol. iv, now in the press, and must therefore form the subject of
a separate book. This is all to the good from the students’ point of
view ; the subject of geographical distribution in time, if treated in
the full and careful manner which we expect from Professor Seward,
may well form a separate volume. We trust that the leisure which
one associates with the mastership of a college in an ancient
Reviews—Professor A. C. Seward—Fossil Plants. 517
university may allow of its speedy completion. Like the growing
point of a Monocotyledon, the scope of Professor Seward’s under-
taking has broadened with its growth, and the completed work will
form a landmark in the literature of paleobotany.
The present volume opens with a general account of recent Cycads,
the headline to which contains a curious misprint, one of the very
few we have noticed in the volume, the general production of which
is excellent, with clear and well-arranged text. ‘The account of the
Pteridosperms was begun in vol. i, but the treatment of the better-
known genera was reserved for the present volume; ‘‘as these
genera are founded to a large extent on anatomical characters
oscillating in their essential features between recent Ferns and
Cycads,”’ this intercalation of a chapter on recent Cycads was a happy
thought. In the second chapter the author resumes his descriptive
account of the Pteridosperms. These are considered under the
headings Lyginopteridew and Medullosee. Under the former is
a full description of Lyginopteris (a name which on principles of
nomenclature replaces the somewhat better-known Lyginodendron),
including vegetative and reproductive organs, with the seed which
was formerly known as Lagenostoma. The subject of nomenclature
is a difficult one for the writer of a textbook on palzobotany.
Having pieced together the fragments which have been described
under different names at different times, he has to decide what name
the more or less perfect entity shall bear; and it must sometimes
happen that a better-known name must give place to one which is
for the moment less well known. Professor Seward is wise to be
guided by definite principles; in a book like the one before us,
which will be a standard textbook for some time, he has the oppor-
tunity of fixing a name for the use of students.
In this chapter the author discusses the use of the term ‘‘seed”’
for the structure represented by Lagenostoma and other Paleozoic
seeds. The difficulty is the absence of an embryo, a very important
feature, the development of the embryo being the outward and visible
sign of the process of fertilization. The opinion is expressed that
this negative character should not be allowed to outweigh the
evidence furnished by morphological features as to the applicability
of the term seed (p. 61). Later (p. 301) the writer refers to ‘‘ the
promotion of the megasporangium and megaspore of the Pteridophyta
to the higher stage represented by the integumented megasporangium
(nucellus) and single megaspore that in the main fulfil the definition
of a seed’’. How, then, shall we define an ovule? The seed of the
modern phanerogam or seed-plant is so characteristic and morpho-
logically well-defined a structure that one somewhat regrets the
application of the same term to these early attempts to achieve the
same biological function. Professor Seward is not, we think, quite
sure of his position, as on each occasion he leans on the stalwart arm
of Professor Oliver. As Professor Oliver says, ‘‘there is a long
chapter in evolution to be deciphered before we can connect . . . the
seed of Lyginodendron with the sporangium of any fern at present
known to us.’”’ We might add, there is a long long trail between
Lyginodendron and the modern seed-bearing plant.
518 Reviews—Handbook of Bedfordshire.
The account of Heterangiwm and the associated seed Spherostoma
follows that of Lyginopteris, after which is a chapter on Medullosee
and the Zrigonocarpus seed-type. The Lyginopteridex and Medul-
lose are regarded as offshoots of a common stock, the latter
occupying a position farther removed. from the filicinean ancestry
than the former.
Under the heading Cycadofilices is a description of several types
represented by stems, but which in the absence of definite informa-
tion with regard to the reproductive organs cannot be assigned to the
Pteridosperms, including among others DMegaloxylon, Cycadoxylon,
Calamopitys, Cladoxylon, and Protopitys; their structure is well
illustrated by photographic reproductions of sections and diagram-
matic figures.
The two following chapters are devoted to the Cordaitales under
the headings Poroxylee, comprising Poroxylon, Cordaitex, including
Cordaites proper with some allied or imperfectly known genera, and
Pityew, including the large petrified stems known as Pitys and other
genera founded on stems of comparable structure. A chapter on
Paleozoic gymnospermous seeds forms a useful comparative study of
selected examples illustrating the remarkable variety in details of
external form and internal structure associated with certain funda-
mental features which they have in common. Here, again, the
illustrations are most helpful.
The concluding chapters deal with the fossil Cycadophyta, These
are represented by the important class Bennettitales and include
Cycadeotdea (more generally known as Bennettites), Walliamsonia,
the recently described Williamsoniella, and other less perfectly known
genera; these forms are fully and carefully described. A chapter
follows dealing (1) with Cycadean stems other than Cycadeordea, the
best known of which are those assigned to Bucklandia, and (2) with
reproductive organs of fossil Cycadean plants which cannot be
assigned to Bennettitales. Some of these, which have been described
by various authors as Carpolithus, agree in external features with the
seeds of modern Cycads, but in the absence of anatomical details
their position must remain doubtful.
The last chapter, Cycadophytan fronds, contains a desenuuam of
a number of genera founded on detached leaves which are believed
to be Cycadean.
A list of works referred to in the text (including vols. iii and iv),
arranged alphabetically under the author’s name, occupies nearly
fifty pages.
A. B. Renptr.
I].—Camprinver County Hanpgooxks.
Beprorpsaire. By C. Gore CoamBers. Cambridge County Hand-
books. pp. x+195. Cambridge University Press. 1917.
LTHOUGH Bedfordshire is one of the smallest of the English
counties, nevertheless it shows a surprising diversity of natural
features and productions. This diversity is closely correlated with
the geological structure of the district. From this point of view the
county may be divided into three sections; firstly, the Jurassic clays
Reviews—Persistent Vents of Stromboli. 519
of the north, which form low, gently rolling, or flat ground, mainly
' occupied by the valley of the Ouse; secondly, the conspicuous ridge
of the Lower Greensand, with its pine-woods and heather, extending
across the county from Leighton Buzzard to Potton and Sandy; and,
thirdly, the Chalk downs of Luton and Dunstable, which rise at
Kensworth Hill to a height of some 800 feet, and afford an excellent
example of the Down type of scenery. Some of the superficial
deposits of Bedfordshire are also of considerable interest, notably the
gravels of Biddenham, which have long been classical in the study of
Palzolithic man in Britain. It was here that the resuits obtained by
Boucher de Pertheson the Somme were first established and extended
for Britain. This discovery formed a notable landmark in the history
of prehistoric archeology.
In this small book Mr. Gore Chambers has given a concise and
well-arranged account of the natural features and products,
archeology, and history of Bedfordshire, showing clearly how the
development of population, communications, and industries is closely
dependent on the geography and geology of the district. Although
not containing within its borders any places of paramount importance,
Bedfordshire was even in very early days an important centre on lines of
communication, since the Icknield Way and the Watling Street crossed
at Dunstable. These great roads are no doubt very ancient, probably
going back to Neolithic times. Again, the Stane Street, an im-
portant road from London to the North, skirted the eastern side of
the county, while the town of Bedford was an important stronghold
at an early date.
The mineral wealth of the county is not great; the coprolite
industry and the quarrying of the Totternhoe Stone for building
purposes are now almost or quite extinct, but the sands of the Lower
Greensand have been largely used for glass-making and other com-
mercial purposes; this is an industry that is likely to increase in the
future. Near Leighton Buzzard there are beds of pure white sand
of very good quality for glass. The yellow iron-stained sands of
Sandy and other districts are chiefly used for building, iron-moulding,
and filter-beds. Bedfordshire is on the whole an agricultural county,
and the experimental work carried on at Woburn is world-famous.
The alluvial soils of the Ivel Valley are specially suitable for market
gardening, and of late years an enormous trade has sprung up in
garden produce for the London market, ordinary garden vegetables
being here grown by hundreds and thousands of acres. It is clear,
therefore, that the industrial prosperity of Bedfordshire is largely
founded on a geological basis.
R. H. Rasratt.
III.—Perrsistence or VENTS at STROMBOLI AND ITS BEARING ON
Vorcantc Mrcwanism. By H. 8S. Wasuineron. Bull. Geol. Soc.
America, vol. xxviii, pp. 249-78, pls. vi-1x.
N this paper the author has brought forward the evidence of the
constancy of position of the vents on the crater terrace of
Stromboli. By a careful comparison of old plans and sketches, going
back as far as 1776, he has established the fact that certainly three,
520 Reviews—The Eruption of Sakura-jima,
and probably more, of these vents have not altered their positions
to any appreciable extent since that date. He compares with this
the constant position of the lava lake, Halemaumau, in the crater of
Kilauea, and suggests that there is some evidence for a similar
constancy at Vesuvius and Etna, though here the information is
much less definite.
From these facts the author draws the following conclusions:
(1) The vents are the openings of conduits which have pierced
through the solid rock for the greater part of their courses. (2) The
lengths of these conduits must be considerable, for, if this were not
so, we should expect vents to break through the thin crust at various
places at different times. (3) The persistence and relatively small
size of the vents, which must be wider than the conduit, indicate
that there has been very little corrosion of the vent by the uprising
magma, which is presumably kept fluid at a lower temperature than
the melting-point of the surrounding walls, owing to its dissolved
gases. (4) The complete absence of synchronism in the activity of
the different vents shows that they communicate individually with
the magma reservoir. (5) Judging by the size of the vents the
conduits cannot be more than ‘‘a few tens of metres’’ wide.
These conclusions, together with the fact that the vents occur at
the top of a scarp more than 2,000 feet high (probably caused by the
subsidence of the north-west portion of the original crater), lead the
author to adopt Daly’s ‘‘ gas-fluxing”’ hypothesis to explain their
formation. This hypothesis is briefly described as follows: Gas
bubbles rise to the top of the magma in the reservoir and accumulate
in irregularities (‘‘cupolas’’) in the roof. These gases are supposed
to be at a higher temperature than the magma owing to their exothemic
interactions and so ‘‘ blowpipe”’ their way up through the overlying
rock. The action of these gases will only extend over a small area,
so that many narrow independent pipes will be formed. This
hypothesis is especially applicable to the formation of the vents on
the Stromboli crater terrace, if this has been formed by the sinking
of a large mass to the north-west, since the magma reservoir may
be assumed to have maintained its original level under the remaining
centre part of the original mountain, which would then be the most
favourable place for the ‘‘ gas-fluxing”’ action to take place.
The paper is illustrated by some very interesting photographs,
sketches, and reproductions of illustrations from the old books dealing
with the volcano.
We Wi
IV.—Tue Erverion or Saxura-sima on January 12, 1914. By
Cartes Davison, Sc.D., F.G.S. Setence Progress, No. 45,
July, 1917, pp. 97-110.
N Science Progress for July, 1917, Dr. Davison gives a very
interesting summary of Professor Omori’s investigations! into
the eruption of Sakura-jima which took place in January and
“The Sakura-jima Eruptions and Earthquakes’’: Bulletin of the
Imperial Earthquake Investigation Committee (Tokyo), vol. viii, pp. 1-34
(1914), 36-179, 181-321 (1916).
Reviews—The Colour of Amethyst, ete. 521
February, 1914. Sakura-jima is an island, one of a series of five
volcanoes situated along a N.N.E.—-S.S. W. line on or near the southern
end of the island of Kyushu, which is the most southerly of the main
islands of the Japanese Empire. The activity of the Japanese
volcanoes is restricted to certain periods, separated by more or less
long periods of quiescence; and in this present active period 194
eruptions occurred from eleven volcanoes between 1909 and 1914.
The eruption was preceded by the usual premonitory warnings, the
- significance of which was so completely understood by,the authorities
that the whole population of the island, some 23,000 in number,
were removed with the loss of only three lives. The paroxysmal
phase was one of extraordinary violence; it began with the ejection
of stones and ashes from one of the main craters, which was followed
somewhat later by the outpouring of lava from two groups of
craterlets on the west and south-east sides of the island; it was also
accompanied by a severe earthquake, which was recorded by European
observatories, and by a small earthquake wave, which was probably
caused by the subsidence of the bottom of the neighbouring
Kagoshima Bay.
Detailed surveys of the district, before and after the eruption, show
considerable elevation (between 30 and 40 feet) of the mass of the
island itself and subsidence of from 4 to 20 inches over the sur-
rounding country. These displacements require the sinking of
a mass of the crust of at least half the volume of the material
ejected during the eruption. ‘The sound phenomena were found to
behave in a normal manner, that is to say that there were two zones,
one near and one far from the volcano, in which the sounds were
separated by a silent zone, the middle line of which lay about
75 miles from the mountain. The chief eruption of Sakura-jima was
associated with eruptions from the other vents in the line. Three
out of four of these were active between January 8 and March 21,
beginning with the most northerly and ending with the most
* southerly.
Wo EAW:
V.—Tue Corovur or Ameruyst, Rose, anp Biur VARIETIES OF
Quartz. By T. L. Warson and R. E. Brarp. Proceedings of
the United States National Museum, Washington, 1917,
pp. 503-63.
ie to the present time but little information is available as to the
cause of the disperse colours of minerals, as distinguished from
the colours due to the actual chemical constituents of the mineral
itself. The authors of this paper have made a careful investigation
of the chemical composition and physical structure of variously
coloured varieties of quartz with a view to discovering the reason of
the wide variations that exist in different types. The principal con-
stituents found which might give rise to colour are manganese,
titanium and iron, with traces of cobalt. On the average of thirteen
analyses it was found that amethyst contains the highest percentage
of manganese, while rose quartz has the highest percentage of
522 Reviews—Magnesite Deposits of Grenville District.
titanium; the quantities are, however, very small, ranging from
‘0005 to 0031 per cent, while iron does not exceed ‘006 per cent.
The authors believe that the colour of amethyst is mainly due to
manganese, which probably exists in the form of colloidal particles of
ultramicroscopic size, consisting of manganese oxide. Since the
colour of rose quartz when destroyed by heat cannot be restored by
daylight or by exposure to radium, it is considered not to be due to
any inorganic substance.
‘he cause of the peculiar blue colour of quartz from Virginia was
also investigated. This is forrd *> > ‘ ghly titaniferous petro-
raphical inte, and 1 ed to be in the main an
ference } ne ue t - ottering of light by minute
itl phic regularity. This is
ur of the quartz of the
‘Leating does not destroy
oloured varieties are com-
I j iting to : 0° C. for ten minutes.
restiga an interesting and suggestive piece of work,
which 18 Well worthy ot imitation on other minerals whose colour is
due to minute quantities of some foreign substance. By way of
criticism it may perhaps be suggested that the authors have scarcely
paid sufficient attention to the possible influence of the iron oxides
present in determining the colour of these varieties of quartz.
R. H. Rasrary.
VI.—Tue Maensstre Deposits or Grenvitte Disrricr, ARGENTEUIL
Country, QuesBec. By M. E. Wrtson, Geological Survey of
Canada. Ottawa, 1917.
i recent times magnesite has become increasingly important as
a refractory mineral for metallurgical purposes, and during the
last three years a demand has sprung up in America for a supply
from home sources, most of the material used having been formerly
imported from Austria and Greece. This has led to the development
of a considerable industry in Quebec. The magnesite is found in the
rocks of the Grenville Series, the oldest subdivision of the Pre-
Cambrian of the district. ‘'hese were originally sediments consisting
of sandstone, shale, and limestone, which have undergone an intense
degree of metamorphism; the limestones have been converted into
erystalline marbles, partly dolomitic, while some varieties contain
a proportion of magnesium carbonate in excess of that required to
form dolomite ; some samples show as little as 7 per cent of lime.
From the descriptions given in this memoir it appears that the
enrichment in magnesia may be due in part at any rate to intrusion
of masses of pyroxenite and other basic rocks rich in magnesia con-
nected with the Buckingham Series. The process may have been
effected largely by the aid of pneumatolytic solutions arising from
basic or ultrabasic magmas. The magnesite is largely associated with
serpentine and diopside rocks, and the whole has been crushed by
dynamic metamorphism into lenticular masses of varying size and
composition. Petrographically the rocks are of great interest: the
Reviews—Mining Operations, South Australia. 523
minerals present include many of those characteristic of areas of
dedolomitization by igneousintrusions. The total amount of magnesite
now in sight is estimated at about 1,000,000 tons, and there may
be a good deal more under certain drift-covered areas.
R. H. R.
VII.—A Review or Mrinine Operations IN THE STATE OF Soura
AUSTRALIA DURING THE HALF-YHAR ENDED JUNE 30, 1916. Compiled
by Lionzezn C. E. Gee and issued under the authority of the
Honourable the Minister of Mines. Adelaide, 1916.
_{J\HIS report deals with the mineral production of South Australia
during the above-mentioned half-year, the minerals with which
it is concerned being mainly copper, gold, salt, and some silver lead.
The search for copper has been stimulated by war demands, and gold
returns are recorded as improving. Logs and detailed sections of
a number of deep bores which were put down in search for copper
are given. Unfortunately these were not successful in striking any
valuable copper deposits. The rocks passed through were mainly
quartzite, mica-schist, and gneiss.
Interesting accounts are given of the prospecting for tungsten
minerals at Callawonga Creek and of a survey of the hundred of
Kongorong, which was carried out to determine the advisability
of boring for petroleum. At Callawonga Creek valuable deposits of
ferberite are found, in conjunction with tourmaline, in veins which
are intermediate in character between pegmatite and quartz veins.
The distribution of the mineral is irregular and in some places it is
associated with finely divided gold. Work has been carried out to
a considerable extent on the surface and the field seems suitable for
deeper work.
The survey of the hundred of Kongorong is a striking example of
the advantage of calling in reliable expert advice before undertaking
any enterprise. Petroleum seepages were reported from this district,
which rested on the evidence of a specimen of asphaltic bitumen,
which was said to have been discovered there. It was also alleged
that the structure of the country as shown by the ‘‘ranges’’ was
suitable for the accumulation of petroleum deposits. The Government
geologist found, on surveying the district, that the ‘‘ranges” were
nothing more than parallel lines of dunes formed during the gradual
elevation of the coast, and that the only solid rock which could be
detected, over most of the area, was a polyzoal limestone, which was
proved by boring to rest on sands and clays with lignite. These
were apparently fairly horizontal, and no clue as to the real structure
of the district could be obtained. Moreover, no traces of petroleum
were found, and it is supposed that the facts of the discovery of the
bitumen were not strictly accurate. The result of this investigation
was that no work was undertaken, and money saved which would
otherwise have been thrown away on a useless enterprise.
The review is illustrated by photographs of the mining operations
and of the Kongorong dunes.
W eH. W..
524 Reviews—The Wolfram Mines of North Queensland.
VIII.—Tue Worrram Mines or Bamrorp anp Carsine Hitt, Norra
Qurenstanp. By L. C. Batt, B.E., Assistant Government
Geologist. Geological Survey of Queensland, Publications No. 248
and 251.
fJVHESE two small mining fields in the North of Queensland
_ produce mainly wolfram, though they also contain a certain
amount of molybdenite and tinstone and at Bamford bismuthite.
The latter field has been in operation since 1893 and has produced
in addition to other minerals about 1,580 tons of wolfram con-
centrates, while the Mount Carbine field produced about 670 tons
between 1906 and 1912. The production of both fields was, at the
time of writing, on the down grade, since the rich surface (‘‘ Shoad ’’)
deposits were exhausted and the deep veins had not been fully
exploited owing to lack of capital and difficulty of working.
The ore in both cases occurs in veins associated with granites. At
Mount Carbine, where the country rock is mainly slate, the mineral
veins are found in the slates; while at Bamford, where the granite
is intrusive into massive porphyry, the veins are generally situated in
the granite itself, near the contact zone, and are accompanied by
greisenization and the formation of quartz rock. At Bamford the
veins often widen out into ‘‘vugs” or broad cavities filled with
quartz, which is the chief ‘‘gangue”’, and metalliferous minerals.
Following the ideas of Daly and Van Hise and also the experiments
of Fouqué and Michel Levy, the author puts forward the hypothesis
that the silica was originally introduced into the veins in the colloid
state. In this condition it would allow the free passage of the
mineralizing gases, but, as the jelly became viscous, the gases would
be trapped and attack the side walls of the veins, forming ‘‘ vugs”’.
Finally the silica was probably precipitated in the crystalline form
owing to the action of tungstic acid, since this has been shown to
exercise a similar action on albumin.
The author describes the mining properties in detail and also the
methods of dealing with the ore, the supplies of water, timber, and
other necessaries of mining communities. ‘'he memoirs are illustrated
by photographs of the scenery and the mines, and also by diagrams
of the most interesting vein phenomena.
Wwe
IX.—Tue Sarsop Formation of Oxecon anpD Wasnineron. By
J. Harten Brerz. Journal of Geology, vol. xxv, 1917, pp. 446-88.
A lee Satsop formation is the name given to a series of deposits
composed of sands and gravels with occasional beds of clay and
lignite, which is found in the valleys of the rivers of Washington and
Oregon. It occurs along the coast, in the valleys of Coast Range, in
the valley between the Coast Range and the Cascade Range, and in
the gorge cut through the Cascade Range by the Columbia River.
It rises from sea-level, or below, on the coast to the height of
3,000 feet in the Cascade Range, and belongs to the cycle of
denudation previous to that now in operation. It was evidently
deposited after the uplift of the Coast Range, as it forms terraces
Reports & Proceedings—Hdinburgh Geological Society. 525
along the valleys cut across this range and also terminates abruptly
against its eastern slope. But in the gorge of the Columbia River
which is cut through the Cascade Range it rises above the river-level,
as it is followed eastwards to the centre of the range, where it begins
to fall, and is found on the eastern side to be again at or near river-
level. It here contains a lava-flow, and is at one place covered by
another. It rests unconformably on the denuded edges of some of
the earlier anticlines.
From this it is seen that the Satsop formation is later than some
of the folding of the range, but earlier than the final uplift. The
Cascade Range has been shown by Russell and others to be an
uplifted, dissected peneplain, which has been called the Methow
peneplain, and the author correlates this with the surface on which
the Satsop formation rests.
By the fossil content of the clays and lignites which it contains it
is shown to be of late Pliocene or possibly Pleistocene age. ‘his
determination would show that the final uplift of the Cascade Range
took place either in very late Pliocene or Pleistocene times.
W. iH. W.
RHPORTS AND PROCHHDIN GS.
EpinsureH GroLocicaL Socrery.
Dr. Flett, President, in. the Chair.
The following paper was read on March 21, 1917 (Abstract received
October 12, 1917): ‘Geology of Kinkell Ness, Fifeshire’’ (with
lantern illustrations). By D. Balsillie, B.Sc., F.G.S.
The largest, best exposed, and most interesting volcanic vent along
the northern shores of Fife is that which has been laid bare at the
headland of Kinkell Ness, and a portion of the enclosed material of |
which has been sculptured into the picturesque shore stack known
_ asthe Rock and Spindle. The margins of the vent were first referred
to by the author, these being easily traceable, he said, except on the
southern and western sides where the fragmental accumulations of
the neck pass into the grass-covered cliff line above high-water mark.
Thereafter the character and arrangement of the materials filling the
old volcano were described in some detail, special attention being
called to the occurrence in the agglomerate of numerous blocks of
a white coral-bearing limestone that probably belongs to the base of
the Carboniferous Limestone Series—this being a higher strati-
graphical horizon than any of the rocks now surrounding the vent.
Though, as emphasized by Sir Archibald Geikie, there 1s no
evidence to show that lava streams were ever emitted at this volcanic
centre, the uprise of igneous material in the chimney is impressively
demonstrated by the masses, dykes, and veins of igneous rock that
ramify through the ash. Some of these intrusions have caught up
such a quantity of extraneous fragments that their simulation of true
agglomerates is very striking and apt to be exceedingly misleading.
The petrographic characters of the basalts are not easy to ascertain
on account of their altered state. Drs. Flett and Campbell are
526 Correspondence—Dr. F. A. Bather.
agreed that, although nepheline cannot possibly be determined in
any of the author’s micro-sections, yet the general resemblance of
the latter to those of the felspathoid-bearing basalts of the
St. Monans and Elie district is so remarkably close as probably to
place beyond question their related origin.
When discussing the geological age of the Rock and Spindle vent,
the author said he was inclined until recently to concur with Sir A.
Geikie in placing it along with other East Fife necks in Permian or,
at all events, in post-Carboniferous time. Revision of this opinion
would, however, now appear necessary. A careful examination of
the Spindle basalt reveals the exceptionally interesting fact that
there are enclosed in it, apparently directly, numerous fish teeth in
a condition of excellent preservation. Dr. Peach believes he has
identified Megalichthys and Psammodus in the specimens collected.
Should these fossils, on fuller investigation, prove not to be derived,
then the vent must be carried back in age to the period of the
Carboniferous Limestone.
CORRESPONDENCE.
SALT-WEATHERING AND SUPPOSED WORM-BORINGS IN
AUSTRALIA.
Sir,—The interesting notice, signed W. H. W., of Mr. E. J. Dunn’s
‘Geological Notes, Northern Territory, Australia” (Grot. Mae.,
March, 1917, p. 184), led me to communicate with Mr. Dunn, who
has kindly sent me copies of his recent papers, on which I venture to
offer the following remarks.
The appearance of contortion observed on the surface of a two-inch
core in presumed Carboniferous rocks, and interpreted by Dr. Jensen
and Mr. Dunn himself as due to the borings of worms, reminds one
rather of some pieces of the Cotham Stone or Landscape Marble (see
Horace B. Woodward, Grou. Mae., March, 1892, p. 110). The rock
before its disturbance appears to have consisted of thin layers of sand
alternating with thin layers of black shale. The latter, being
carbonaceous, may well have contained in places a considerable
amount of decaying organic matter. Consequently the explanation
of these disturbances may be the same as that put forward by
Mr. Beeby Thomson for the Cotham Marble (August, 1894, Quart.
Journ. Geol. Soc., vol. 1, pp. 893-410). That is to say, bubbles of
gas springing from the decomposing carbonaceous matter pass through
the overlying lamine and throw them into confusion. When the
streams of bubbles are concentrated in definite places naturally
a tubular form is assumed; hence the resemblance to worm-borings.
Here one may recall the somewhat similar explanation which
Professor A. G. Hégbom has given of the Scolithus sandstone and
the Pipe-rock (1915, Bull. Geol. Inst. Upsala, vol. xiii, pp. 45-60).
And it is perhaps appropriate to mention here that in 1911 Mr. W. H.
Twelvetrees, Government Geologist of Tasmania, sent to the Natural
History Museum two specimens of ‘‘pipe-stem sandstone” of
supposed annelid origin, but showing in thin section no structure
other than grains of sand. ‘‘ For the most part,” said Mr. Twelve-
trees, ‘‘the tubes are vertical to the bedding, but occasionally we
Correspondence—Dr. F. A. Bather. 527
find them parallel to it. Sometimes they are as thick as a pencil.
Sometimes they are trumpet-shaped. At one time we thought they
were restricted to one geological horizon, but they evidently persist
from our Cambrian or Cambro-Ordovician conglomerate, in which
they occur sparsely, through the sandstone of doubtful Cambrian
or Ordovician age to Silurian sandstone, in which they are also rare.”’
The specimens are now in the Geological Department, registered
A 1658.
In a reply to Mr. Twelvetrees, dated September 30, 1911, I com-
pared the specimens with similar structures in the Cambrian
sandstones of this country and of Sweden, in particular with
a specimen obtained by me at Bergquara in Smaland (Brit.
Mus., Geol. Dept., A 1356), where such appearances are fairly
common and have been referred to Scolithus linearis, Hall. Descrip-
tions of these are given by N. O. Holst (1893, Sveriges Geol.
Undersékning, ser. C, No. 130, p. 6) and Nathorst (1892, Sveriges
Geologt, p. 117 and text-figures on p. 118). Though usually
interpreted as the filled burrows of worms, Nathorst questions
whether the structure has not rather arisen in a mechanical way.
The cylinders are often packed so closely that I too was ‘‘ inclined to
regard the structure as due to some mechanical agency”. Some
American specimens in the British Museum, labelled Scolithus,
do indicate the existence of burrows subsequently filled; but in the
pipe-rock there is no evidence of this. I do not, however, under-
stand how the tubes can ever be parallel to the bedding, as stated by
Mr. Twelvetrees, if formed by ascending bubbles.
In another note (Proc. Roy. Soc. Victoria, n.s., vol. x, pp. 209-10)
which Mr. Dunn published in May, 1898, he was tempted to ascribe
numerous perforations in a decomposed steatitic rock near Coolgardie
to worms, larve, or flies. He mentions, however, that the roots of
eucalyptus trees follow these perforations to as great a depth as
150 feet from the surface. May it not be the case that the
perforations were actually made by the eucalyptus roots? Such an
action is by no means uncommon.
The weathering action of salt-solution through repeated wettings
and dryings is one that I have attempted to apply in removing the
matrix from the surface of fossils, or inducing differential weathering
of a fossiliferous limestone with impure matrix. The mechanical
principle of crystallization involved in the weathering is, as
Mr. Dunn says, an intensification of the principle of repeated
freezing and thawing in winter, and is more convenient for the
paleontologist. The same effect may be attained by the use of the more
readily crystallizing salt, sulphate of magnesia (Epsom salts). It is,
however, a question whether there may not be in the case of sodium
chloride some chemical action as well. Here reference may be made
to the paper read by Professor R. C. Wallace at the Manchester
Meeting of the British Association, 1915, ‘‘ On the Corrosive Action
of certain Brines in Manitoba.”’ The third paragraph of the
Abstract (published in the Association Report, p. 427, and in the
Grot. Mac., Jan. 1916, p. 31) indicates a considerable chemical
action, due to the fact that a persistent film of concentrated sodium
528 Obituary—Professor Edward Hull.
chloride acts in conjunction with the gases of the atmosphere. The
evidence for all this is presumably given in Professor Wallace’s
complete paper, but I do not know whether that has yet been
published. In the case of Mr. Dunn’s pebbles, instead of a persistent
film there is regular alternation of wet and dry, so that the chemical
action, if any, must be considerably less than the mechanical; mere
attrition appears to be excluded.
F. A. Baruer.
(@ pS ssa OP Naas
FRANCOIS CYRILLE GRAND’EURY.
BoRN Marcu 9, 1839. DIED JULY 22, 1917.
By the death of M. Grand’EKury paleobotany loses one of its most
distinguished and energetic pioneers. As a mining engineer who
spent his life in coal-fields, he had unrivalled opportunities for
observing Carboniferous plants in situ, and he always made the most
of every discovery which came under his notice. His special studies
enabled him to correlate various roots, stems, foliage, and fruits
which as isolated fossils had received separate names. He also made
many important observations bearing on the origin of coal. His
well-known memoir on the Carboniferous Flora of the Loire was
published by the Paris Academy of Sciences so long ago as 1876.
His great work on the Coal Basin of the Gard appeared in 1890.
Numerous other publications culminated in his Recherches géo-
botaniques, which were in course of issue at the time of his death.
PROFESSOR EDWARD HULL,
M.A., LL.D., F.R.S., late Director Geological Survey of Ireland, and
Professor of Geology Royal College of Science, Dublin.
Born May 21, 1829. DIED OCTOBER 18, 1917.
We regret to record the death of Professor Hull, at his residence,
14 Stanley Gardens, Notting Hill, W. 11, on October 18, aged 88.
A memorial service was held on Monday, October 22, at St. Peter’s
Church, Kensington Park Road, Notting Hill, and was attended by
numerous representative scientific men.
A record of his life-work as a geologist will appear in December.
GEORGE C. CRICK,
Assoc. R.S.M., F.G.S., of the Geological Department, British Museum
(Natural History).
BORN OCTOBER 9, 1856. DIED OCTOER 18, 1917.
Wirn sorrow we record the death at his residence, 20 Bernard
Gardens, Wimbledon, in his 62nd year, of our former colleague,
Mr. George C. Crick, well known as an authority on the fossil
Cephalopoda, and author of numerous papers in this Magazine, the
Proceedings of the Malacological Society, and the Quarterly Journal
of the Geological Society.
A notice of Mr. Crick’s scientific work will appear next month.
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The Ambrym Eruptions of 1913-14,
New Hebrides. By Prof. J. W.
GreGory, D.Sc., F.R.S. (With
is a, Map, Plate XXXIII,) ..........., 529
_ Theso-called Coprolites of Ichthyo-
saurians and Labyrinthodonts.
By ARTHUR SMITH WOODWARD,
Li.D., F.R.S., (Plate XXXIV
BUC REXTHOULe.) cise cccsesttwees 540
Unconformity between the Cre-
{| _ taceous and Older Rocks in East
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Page
By HERBERT ARTHUR
Baker, B.Sc., F.G.S. (With
two Maps and Section.)............ 542
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THE
G Ik O LOGIC AL MAGAZINE
NEWOISERIES. DECADE Viikw sVOEAIVE
No. XII.— DECEMBER, 1917.
ORIGINAL ARTICLES.
—
I1.—Tue AmBrym Ervprions ofr 1913-14.!
By Professor J. W. GREGORY, D.Sc., F.R.S.
(WITH A MAP, PLATE XXXIII.)
The Constituents of the New Hebrides.
The Voleanic History of Ambrym to 1894.
The 1894 Hruption.
The Features of the 1913 Kruption—
(a) The Explosion Trough.
(6) The Lava Pipes.
(c) The Fissure Eruptions.
The Rocks of the 1913 Eruption.
General Relations of the Ambrym Eruptions.
References.
Rwpe
TID Or
1. Tse Constrrvents oF tHE New Hesripes.
f|\HE rocks of the New Hebrides belong to at least four groups—
two series of limestones and two series of volcanic rocks. The
islands are sometimes referred to as if composed only of recent
voleanic and coral formations. The existence of a series of old rocks
has been believed from the records of gneiss on Espiritu Santo by
Levat, and of ores of iron, copper, and nickel. The asserted presence
_ of these materials suggested that the older rocks of New Caledonia
form the foundation of the New Hebrides. The existence of the ores
and gneiss is, however, discredited by Sir Douglas Mawson (1905,
pp. 422, 484-5); he remarked that he had examined ‘‘ small samples
of copper, manganese, and other ores supposed to have been collected
in the group”? (Mawson, 1905, p. 435). He did not confirm this
supposition, though admitting that traces of these metals might
occur.
Lieut. Frederick (1893) obviously identified some of the New
Hebrides rocks as ‘‘claystones’’, which may indicate that he
recognized some older sediments. If this statement had been
confirmed it would have been his most important contribution to the
geology of the archipelago; but it was apparently distrusted, and
was excluded from his published paper; and his identification is only
known from a remark by Sir Archibald Geikie in the discussion.
1 [The description of the Voleanic Eruption of 1913 on Ambrym Island,
Neéw Hebrides, by the Rev. M. Frater, appeared in the GEOLOGICAL MAGAZINE
for November, 1917, pp. 496-503, and was communicated by Professor
J. W. Gregory to the Editor. |
DECADE VI.—VOL. IV.—NO. XII. 34
530 Professor J. W. Gregory—The Ambrym Eruptions,
Although the existence of the suspected early rocks is unconfirmed,
Sir D. Mawson collected at Espiritu Santo a series of limestones
which Mr. Chapman (1905, p. 273) identified by their Foraminifera
(Lepidocyclina) as Aquitanian and Burdigalian. They are therefore
Lower Miocene, and would be also Upper Oligocene according to the
classification which refers the Aquitanian to the Oligocene.
These Lepidocyclina limestones are shown by Mawson to rest on an
older volcanic series, which he attributes to the Oligocene or the
base of the Miocene. ‘The limestones are burst through by a later
volcanic series, the earlier tuffs of which Mawson regards as possibly
Pliocene. ‘These tuffs form the beginning of the volcanic period that
includes the modern eruptions.
The Miocene rocks occur in south-western Espiritu Santo, and
their arrangement shows that they are part of a great upfold which
formed the New Hebrides ridge.
The later limestones are recent coral ee Some of them have
been raised high above sea-level. On Efate (Sandwich Island)
limestones, sina are regarded as raised coral reefs, occur 1,500 feet
above sea-level (Frederick, 1913, p. 227).
The bulk of the archipelago consists of volcanic material belonging
to the later eruptions. ‘The archipelago is part of the great volcanic
line which passes along the Pacific border of Australasia from New
Guinea through the Solomon Islands to New Zealand. The New
Hebrides volcanoes have been in frequent eruption. ‘Tanna, as
Mr. Frater remarks, is of the Strombolian type owing to its chronic
activity since it was seen in 1774 by Captain Cook, who was the
first European to visit the Archipelago. Ambrym was also then in
eruption. Lopevi, to the south of Ambrym (4,755 feet high), is
a smaller island with a regular volcanic cone. It was in eruption in
1864 (Purey-Cust, 1896, pp. 3-4). It is said to be the highest peak
in the archipelago, though according to the Sailing Directory, Pacific
Islands, vol. ii, 4th ed., 1908, p. 385, Espiritu Santo rises to between
5,000 and 6,000 feet.
2. Tue Vorcanic Hisrory or AmBrym To 1894.
The eruptions on Ambrym occur at irregular intervals and include
explosions of paroxysmal violence. The records collected by
Admiral Purey-Cust (1896, pp. 5-6) indicate a disastrous eruption,
which, judging from the probable age of the old man who
remembered it, happened about 1820. Like the chief later eruptions,
it was at the western end of the island; it poured lava into the sea
at Craig Point. Moderate activity is recorded by the officers of
a mission schooner, the Southern Cross, in 1870, and it is also
reported as having ‘been in er uption in 1883 or 1884 (Purey-Cust,
1896, p. 8). Lieut. Moore of the Dart stated that in 1883 large
quantities of volcanic dust fell from Ambrym to the north and north-
west of the island, but that no lava had been discharged for some
years (Purey-Cust, 1896, p. 5). Mt. Marum, one of the two large
craters in the middle of the island, was last active in 1888. A few
ne after it became dormant eruptions built up the crater known
‘‘Woleano”’, of which the wall was breached by a lava stream, that
—_
PA
/
New Hebrides, of 1913-14. 531
reached the sea at the south-eastern corner of the island. The old
crater of Mt. Benbow has apparently not been active in historic
times until 1913; it was visited by Lieut. Beresford from H.M.S. Dart
in 1883, when the small crater on the eastern side of Mt. Marum was
mildly active (Beresford, 1884, p. 131).
3. Tur 1894 Eruprion.
The first great eruption of which there is adequate knowledge
occurred in October and November, 1894. Fortunately Commander,
now Admiral, Purey-Cust had just completed a survey of the island
in H.M.S. Dart, and he was able to observe the eruption from all
sides of the island and to visit the most interesting localities. He
published a most valuable report on the eruption, issued by the
Hydrographic Department of the Admiralty, with an appendix upon
the rocks by Professor Judd. Most of Admiral Purey-Cust’s report was
also published in the Geographical Journal (vol. vii, pp. 585-602).
For comparison with the recent eruption the chief features of that
of 1894 may be summarized from Admiral Purey-Cust’s report.
That eruption began on the evening of October 15, though the glare
then was attributed to a bush fire. Early on the 16th it was obvious
that one of the volcanoes was in active eruption, for at daybreak
a high cloud was suddenly projected from the centre of the island.
A lava stream, marked by a line of burning bush, was flowing down
the northern slopes. It reached the coast at 7.45 a.m., just east of
Krong Point. Its entrance to the sea was watched from the Dart
at the distance of 300 yards. The lava stream was from 20 to 30
yards wide, and a pillar of steam rose to the height of 4,600 feet.
In the afternoon flames appeared to the south of the Mission - Station
of Lon-wol-wol at Dip Point, and most of the natives were transferred _
from the settlements there to the north-western part of the island.
Next day, the 17th, the south-eastern crater, Volcano, was quiescent,
and the natives at Dip Point reported ‘‘ Fire he finish”’; it continued,
_ however, further east, for at 4 p.m. a cloud pillar was shot upward
from Mt. Benbow to the height of 15,000 feet. On the 20th the
natives were taken back to the settlement at Dip Point, as the danger
there was over. Commander Purey-Cust landed with a party and
walked from Dip Point along the track southward across the island ;
progress on the path was barred by two narrow lava streams flowing
westward from a large sheet of lava to the west of the village of
Fo-luk. The smaller stream was 10 feet high and was flowing at the
rate of 4 or 5 feet per hour. The larger stream was 300 or 400
yards wide. On October 23 Admiral Purey-Cust visited the centre
of the island and reached the northern edge of the Benbow crater.
It had a flat floor, about a mile in diameter, surrounded by precipitous
sides from 800 to 1,700 feet high. On the floor of the crater was
a group of vents from which steam was rising to the height of 2,000
to 3,000 feet above the crater. On November 7 another explosion
from Benbow hurled a column of dust-charged steam in ten minutes
to the height of 26,000 feet. On November 21 the crater of Benbow
was revisited and it was found that a fissure vent had been opened on
its floor, no doubt by the explosion of November 7. Lieut. Dawson
532 Professor J. W. Gregory—The Ambrym Eruptions,
also on the 21st visited Mt. Marum. He described it as a perfect
crater 1 mile east and west by three-quarters of a mile north and
south, with very steep walls and a pool of water in the centre. It
was therefore not active, but steam was rising from the small crater
on the eastern side. Later eruptions of this series occurred at
‘‘Voleano’’, which was seen in eruption at the end of December,
1894, by the French man-of-war Scorff, and another eruption,
apparently at the western end of the island, happened on February 10,
1895 (Purey-Cust, 1896, pp. 17, 18). The 1894 eruptions appear
to have occasioned an uprise of 1 or 2 feet of the ground around Dip
Point (Purey-Cust, 1896, pp. 21-2).
Admiral Purey-Cust concludes that this series of eruptions were
confined to an approximately east and west line passing through
Mt. Benbow, Fo-luk, and the western end of the island. At the
north-eastern part of Ambrym even the earthquakes were slight,
while neither the flow nor temperature of the hot springs on the
northern and southern coasts was altered. Moreover, not only was
Mt. Benbow active, while its neighbour, Mt. Marum, remained
quiescent, but the two vents in the crater of Benbow, although only
a few yards apart, seemed to lead from entirely different sources.
He attributed the western eruptions to lava, finding no outlet in the
centre of the island, having burst from the fissure where it traversed
the lower ground at the western end.
4. Tuer Features oF THE 1913 Ervuprion.
(a) Zhe Explosion Trough.
The 1894 eruption was followed by nineteen years of comparative
quiescence, though the vents on Mt. Benbow generally discharged
clouds of steam. In December, 1913, a paroxysmal eruption followed
on generally similar lines to the eruption of 1894, though with some
more disastrous and remarkable effects. Mr. Frater’s account shows
- that it began with a series of paroxysmal explosions followed by the
emission of lava from a series of vents on an east and west line.
The most dramatic episode of this eruption was the explosion which,
like a mine, blew up the Mission Hospital of Lon-wol-wol. Admiral
Purey-Cust (1896, p. 6) described the depression to the south of
Dip Point, on the north-eastern side of Minnei Peak (1,245 feet), as
a distinct old crater; he said it was half a mile in diameter, with an
almost flat floor covered by scrub, bounded by perpendicular sides,
and open, however, to the north. The new edition of the Admiralty
Chart of Ambrym shows this crater better defined, for the breach on
the north has been repaired. The main eruption of 1913 occurred
to the north of this old crater on the plain formerly occupied by the
Mission Station.
The chief line of modern volcanic activity on Ambrym through
Volcano, Mts. Marum and Benbow, trends to the west-north-west,
and if continued in that course beyond Fo-luk would pass under the
site of the mission. The hospital was hurled into the air by an
explosion just as that at Tarawera in New Zealand in 1886 blew up
the Pink and White l'erraces and scattered their fragments over the
New Hebrides, of 1913-1. 533
surrounding area. This explosion on Ambrym formed a volcanic
trough more than a mile long by about a quarter of a mile wide, with
its floor in places 50 feet below sea-level; as itis breached to the
north, the sea has poured in and the site of the hospital is now
occupied by a somewhat fiord-like inlet, which is T-shaped, and has
a threshold across its entrance. Subsequently a submarine eruption
built up the base of Sealark Hill, which has been raised to the height
of 330 feet, and has extended the island for about half a mile
seaward.
The change produced in the outline of this part of the island by the
eruption is shown on the map, Pl. XX XIII; the broken line represents
the original course of the coast, taken from the Admiralty Chart of
1894, and the full line represents the coast after the eruption of 1913
from the survey of H.M.S. Sealark under Commander Hancock.
(b) The Lava Pipes.
A second remarkable feature of these Ambrym eruptions is that
the lava-flows are extraordinarily narrow in proportion to their
length. Thus in the eruption of 1894 the lava stream which
entered the sea near Krong Point was over 6 miles long. Admiral
Purey-Cust (1896, pp. 7, 13, 16) records its width at four places—
at the shore, where it was 20-30 yards wide; further inland,
30 yards wide; at its sharp bend east of Fo-luk, 30 yards wide;
and at its upper part along its east to west course, where it was in
places only about 10 yards wide (Purey-Cust, 1896, No. 1, p. 16;
but said to be 10 feet wide in 1896, No. 2, p. 600). The lava sheet
west of Fo-luk fed two streams which flowed south-westward; both
are represented on the map as very narrow. The southern stream
discharged from a tongue some 300 or 400 yards wide (Purey-Cust,
1896, p. 9) projecting from the wide lava sheet. The lava stream
of 1913 which reached the sea at Baulap, flowed from the eastern
- end of the Fo-luk fissure ; it was 5 miles long and is represented on
the Admiralty Chart as a long narrow sinuous line. The discharge
from the vent to the south-east of Mt. Marum formed a wide laya
sheet, 3 miles in length from east to west, and nearly 24 miles wide
from north to south; at its western end it gave rise to a lava stream
which was discharged in January, 1914, and reached the sea at Port
Vato; its length was 5 miles, and it also is represented on the new
edition of the Admiralty Chart as a long narrow stream.
The Admiralty Chart no doubt indicates only the approximate
course of the lava streams, and it is not intended to give precise
evidence as to their width. Exact information as to the width of the
flows would be of value. The available evidence indicates that they
are remarkably narrow. Admiral Purey-Cust remarks (1896, p. 13)
that the stream west of Fo-luk flowed down a deep gully; and the
narrowness of the streams is doubtless due to their being confined
between the banks of steep gullies. _ A stream 6 miles long and
maintaining an average width of 30 yards must be fed by the flow of
material down the centre while the outside has cooled to form a solid
pipe.
534 Professor J. W. Gregory—The Ambrym Eruptions,
Admiral Purey-Cust has described the upper part of the Krong
Point lava stream as hollow, since he heard the flow of a swift stream
of water along the centre (1896, p. 17). He also describes (ibid.,
p. 18) the lava stream in the gully west of Fo-luk as concave ; the
upper surface has apparently sagged owing to the central lava having
flowed away and left the roof unsupported.
The characteristic form of the lava-flows on Ambrym is therefore —
that of lava pipes, in which the length may be 300 times the breadth,
rather than lava streams of normal proportions.
(c) Dhe Fissure Eruptions.
‘The tubular structure of these lava-flows is the more remarkable
as most of them appear to have been the result of fissure eruptions.
According to the Rev. M. Frater the lava from the western vents
discharged from-a series of fissures, through which the lava quietly
welled ‘forth without violent explosions. Thus he says. that near
Meltungan ‘‘streams of lava literally gushed out of the fissures
without intermittent explosions of steam’’. According to the usual
conception of fissure eruptions they normally give rise to sheets of
lava; but the Ambrym lava must have been so liquid that it
discharged through the lowest outlet from the fissure like water from
a reservoir; this phenomenon is well illustrated by the narrow
stream which overflowed from the great lava sheet south of Mt. Marum
and reached the sea at Port Vato. If the fissure had been opened
on the top of the level plateau it might have formed a widespread
lava sheet; but as each fissure was discharged through a lateral
notch into some narrow gully it gave rise to a narrow lava pipe.
That the western eruptions of Ambrym in 1894 also were from
fissures is indicated by the descriptions of Admiral Purey-Cust.
He states (1896, No. 2, p. 600) that at Single Palm Hill ‘‘ There
was no regular crater, and it was evident that the lava had burst up
from the ground in all directions, and had been either violently
impelled up the hillsides by hydrostatic pressure, or else the hillsides
had been themselves split open’
Another striking feature of the er uption was the contrast between
the quiet discharge from the fissure near Fo-luk and the explosion
from the western end of the same fissure at Lon-wol-wol. According
to Mr. Frater the lava that escaped quietly from the fissures was as
saturated with steam as that which was thrown explosively from the
central craters. This difference was probably due to the varying
amount of water in the ground traversed by the lava. The fissure
near Fo-luk ran along the central ridge of the island a little to the
south of the crest, which there rises in places to 1,210 and 1,310 feet
above sea-level. This ridge being well drained on both sides was
relatively dry. The only ‘steam available at the eruption there was
brought up by the rising lava. But the fissure at Lon-wol-wol was
close to the coast and only slightly above sea-level. The ground
there was probably saturated with water, and the ascent of the lava
along this fissure produced superheated steam, which suddenly found
relief in the explosion that formed the volcanic trough.
New Hebrides, of 1913-14. 535
5. Tue Rocks or tHe 1913 Eruption.
‘The volcanic rocks of the New Hebrides, according to the previous
records, vary from andesites to basalts or dolerite.. Professor Judd
(in Purey-Cust, 1896, p. 23) described the specimens collected by
Admiral Purey-Cust from Ambrym and some adjacent islands as
being all very typical augite-andesites and as strikingly uniform in
petrographic character. The dominant felspar he identified as
microtine. Sir Jethro Teall (Frederick, 1893, App., pp. 229-380),
who determined the collection brought by Lieut. Frederick from the -
New Hebrides, identified the specimens from the ‘‘hot ground”? at
50 feet above sea-level on Tongoa (one of the Shepherd Islands to
the south-east of Api), and from anna as augite andesites ; the rock
from the summit of Tongoa, 1,584 feet, he identified as basalt, and
a specimen from the island of Makura asa dolerite. According to
Sir Douglas Mawson (1905, pp. 459, etc.) the volcanic rocks of the
New Hebrides are mainly andesites and basalts, including a horn-
blende-andesite at Efaté, and a basalt-porphyrite from Man, an island
north-east of Kfaté. He estimates (Mawson, Proc. Linn. Soc. N.S.W.,
1905, xxx, p. 463) the mineral composition of the latter as follows:
its chemical composition is given as No. 2 on p. 538.
1st Generation. 2nd Generation. Total.
: ‘ Per cent. Per cent. Per cent.
Felspar-intermediate labradorite,
Abi Any -\e 33 = 33
Felspar-basic andesine, Abs Any (sic) — 26 26
Pyroxene . : : : j —_— 24 24
Olivine. é 6 , : 1-8 8-2 10
Magnetite . ; : : 3 Inseparable 7
100
Apatite . : 0 ¢ : minute.
Some lavas from the 1913 eruptions collected at Dip Point, Ambrym,
by Professor W. M. Davis, and others obtained by Rev. P. Milne
have been described by Professor Marshall (1915); he identified
them all as basalts composed of bytownite-labradorite, diopside-
augite, sometimes grains of olivine, and a brown glass densely filled
with magnetite dust. Professor Lacroix has also described the lavas
from the 1913 eruption and determined them as augitic labradorites
too poor in olivine to be true basalts. According to his determination
the normative mineral composition is felspar 64 per cent, diopside
22 per cent, olivine 5 per cent, magnetite and ilmenite 9 per cent.
Professor Lacroix includes an analysis by Boiteau, which is quoted
as No. 1 in the table on p.538. He calls the rock an andose allied to *
camptonose, of a kind frequent among basaltic lavas and as nearly
allied to those of Kilauea. Some of the old lavas thrown out by the
eruption he says are true basalts.
According to Professor Iddings (1913, vol. ii, p. 648) the volcanic
rocks of the New Hebrides are chiefly basalts with phenocrysts of
olivine.
_ Mr. Frater’s collection includes representatives of the chief 1913
and 1914 lava-flows, and the rocks are all basalts, are mostly glassy,
586 Professor J. W. Gregory—The Ambrym Eruptions,
and usually containing some olivine. The lavas represented are as
follows. .
The Baulap lava pipe, according to four specimens collected
approximately equidistant along it, consists of olivine basalt and
olivine-basalt glass.
The Craig lava-flow from the main fissures at Fo-luk discharged
as a lava pipe down a gully; it then spread out as a wide sheet,
from which a lava pipe descended almost to the sea near Craig Point.
The specimens are very glassy basalts; in one of them I observed no
olivine, which occurs, however, in a specimen from the lowest end of
this flow near Craig Point.
The Lowea Valley lava-flow is a lava pipe that discharged north
and north-west from the lava sheet, which also fed the Craig lava
pipe; it is a very vesicular Blassy basalt, with sparse olivine and
larger augites.
Lava-flow from north of Fo-luk west-south-westward just south of
‘747 foot” hill. An olivine basalt with large augites.
Harbour Crater—from the trough formed by the explosion at
Lon-wol-wol; a very vesicular glassy augite basalt.
South-east of Mt. Marum, from the vent of January 1, 1914, which
formed the large lava sheet on the high plain to the south of
Mts. Marum and Benbow, and fed the Port Vato lava pipe. Glassy
olivine basalt with augite.
The typical rock of the 1913 eruptions, as represented in
Mr. Frater’s collection, is a basic lava, rich in black glass, and
containing glomero-porphyritic groups of a basic felspar, which
Mr. Tyrrell has determined as Ab, An,. The larger phenocrysts
show zonal structure and are often deeply corroded. ‘The ground-
mass is sometimes a dense black glass, and at others consists mainly
of felspar laths with granules of augite and olivine. The olivine is
usually in small grains, often enclosed in the radial groups of felspar,
but it 1s sometimes in well-developed crystals. The proportion of
olivine is small and in some sections none were observed.
Mr. Tyrrell has kindly examined the sections, and describes them
as follows:—
‘‘ With the exception of slide D [from south of hill 747, west of
Fo-luk] all the rocks consist of the same olivine-poor basalt, and
differ only in texture, amount of glass, and vesicularity. In general
the phenocrysts are comparatively sparse and small. They consist
of plagioclase, augite, and olivine, named in order of abundance.
The felspar is basic labradorite (Ab, An,), and is developed in curious
little glomeroporphyritic groups with one or two crystals of olivine,
“rarely with augite. The augite is a yellowish-green diopsidic variety
with extinction 40°. The groundmass, when dominantly crystalline,
consists of granular augite and magnetite, with lathy felspars
(Ab, An,). The augite + magnetite S felspar—a basaltic type of
groundmass. Many of the rocks, however, contain a considerable
amount of dark glass and are highly vesicular. In these glassy and
vesicular varieties the felspar-phenocrysts appear to become more
abundant relative to augite and olivine; and the olivine occasionally
appears as tiny euhedral crystals in the groundmass. A very rough
New Hebrides, of 1913-14. 537
estimate of relative proportions in the most nearly holocrystalline
varieties 1s—
Phenocrysts, 8 per cent.
Labradorite (Abs ae ;
Augite . :
Olivine.
Groundmass, 92 per cent.
Labradorite (Ab a) j
Augite . 6
Magnetite
Glass + eryptocr ystalline mater ial .
F bo Or
e He OO
bo or or ©
‘‘ Augite is decidedly more abundant in slide Bd [from the west
end of the lava sheet east of Craig Cove] than in others of the
same rock.
‘*Slide D is an olivine-basalt with much more abundant phenocrysts
than the above. Olivine and augite occur in large crystals only
slightly inferior to the felspar in quantity. Phenocrysts slightly <
or = groundmass.
“ (xouddn) Uvij0409 to yu) Uaayyaon SSS
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qd SNOFIVLSYI— ANS BHL 4O NOILISodNwoD
ae (verpurjyied vo)
} CY) Pmitel prog ousneqriZyy paosysy
OX = 5
y — X
, then, it can be seen that the deposition,
subsequent upheaval and denudation, and imparted strike and dip of
7
Herbert A. Baker—Unconformity between
co)
of the various belts of Jurassic strata, and indicate, in a general
In a general way
way, the approximate positions of certain boundaries.
in Map below, Fig. 1.
544
Aouxo(f) ~S > paohing
Vy = ~\4¢ & ajosuadoy
Planar
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Cretaceous and Older Rocks in East Kent. 545
the Jurassics of Kast Kent are distinctly related to the movements of
an axis of unrest lying to the east and north of Kent and possessing
a N.W.-S.E. alignment.
Further west in Kent the Bobbing boring showed the sub-
Cretaceous surface to be composed of Oxfordian strata, as did also
that at Chatham Dockyard, thus demonstrating that the Oxfordian
outcrop pursues the same general north-westerly or west-north-
westerly direction for a considerable distance.
A point of interest concerning the position of the northward limit
of the Corallian outcrop in East Kent may be noted. It will be
observed that the line passes south of Oxney and Maydensole, north of
Waldershare, and south of Barfreston, and then turns sharply north-
ward in the neighbourhood of the Snowdown sinking (between
Fredville and Barfreston) and resumes its general north-westerly
course northward of Fredville. his deflection may perhaps be due
to proximity with some anticlinal disturbance, but is more probably
the indication of a pre-Cretaceous dip-fault here, possessing a
westerly downthrow, which has resulted in a lateral displacement of
the outcrops southward on the eastern side of the fault. In this
connexion it is interesting to recall the anomalous dip of the Coal-
measures observed at the Snowdown Colliery, where, instead of a dip
of about 38° in a direction 35° west of south, as observed in the
Tilmanstone Colliery, one of 23° in a direction 20° north of east was
found. It appears likely that faulting may have taken place here in
consequence of the occurrence of a sagging movement in the south-
west during deposition under isostatic conditions (see below).
The denudation of the sub-Cretaceous surface in East Kent
obviously reached an advanced stage, and the area must have been
reduced almost to a smooth peneplain before the deposition of the
Wealden upon it. Probably, too, in earliest Cretaceous times the
peneplain was corraded to some extent by stream action prior to
the commencement of deposition, but not sufficiently so to produce
‘any very marked variations in level upon it. If we eliminate the
effects of post- Lower Cretaceous movements from the area by correcting
the present base of the Gault here to a datum-plane at Ordnance
Datum and consider the levels of the base of the Wealden in relation
to it, the latter is seen to present the form of a plain possessing
a very gentle southerly slope, the difference in level between the
highest and lowest points upon it being less than 200 feet.
Seeing that in Hast Kent ‘‘the strata between the Oxford Clay and
the main limestones of the Great Oolite Series . . . appear to repre-
sent a continuous sequence of marine deposits’’,! and also that ‘the —
deposition of clayey sediments went on uninterruptedly from
Oxfordian to Kimmeridgian times”,' the advanced stage to which
the denudation attained is at first sight surprising, but on reflection
it will be seen that denudation in the north-east must have been con-
temporaneous with deposition in the south-west during the latter
part of Jurassic times. The general movement of uplift of the
British region in Portlandian times must have exposed to denudation
an area of Kimmeridge Clay fringing the Paleozoic ridge in the
1 Lamplugh, loc. cit.
DECADE VI.—VOL. IV.—NO. XII. 35
546 Herbert A. Baker—Unconformity between
north-east while deposition of Portlandian sediments was in progress
in the south-west. This state of affairs persisted into Purbeckian
times, and was probably accentuated by differential movement.
Direct posthumous uplift along the axis may have occurred in post-
Portlandian times, but it seems likely that we have in East Kent, on
the western flank of the ancient ridge, an illustration of the operation
of the principle of isostasy, a sagging of the area of deposition in the
south-west, under the weight of the great accumulation of Jurassic
strata, being compensated by concomitant uplift in the north-east.
Differential movement of this character was apparently taking place
in Purbeckian times, for although the Purbeck appears never to
have extended far to the north-east, yet it transgresses on to the
Kimmeridgian. .
Passing on now to consider the character of the Cretaceous rocks
which overstep the successive members of the Jurassic until they
rest upon the Paleozoic floor, the writer ventures to remark that it
would probably be difficult to find a happier illustration of the utility
of constructing maps of isopachyte systems of strata than that
afforded by the Wealden of East Kent. The isopachytes are found
to throw a very interesting light upon the question of the conditions
under which these strata were deposited (see Map 2).
It is immediately apparent that the isopachytes are of a character
very different from that possessed by those of a marine formation.
They are clearly the lines of an estuarine deposit, and indicate
plainly that the Wealden of East Kent was deposited by a river
flowing from the north-east. In the view of the writer this river
was consequent upon the easterly Charnian ridge. South of
Woodnesborough it appears to have divided into two streams which
turned south-east and flowed as subsequent or strike streams into the
Wealden lake. The southerly slope of the land being now
exceedingly gentle in the Kast Kent area, in consequence of much
levelling up having been effected by the steady accumulation of great
wedge-like masses of Mesozoics to the south-westward, local con-
ditions became significant in deciding the course of the streams when
the influence of the primary ridge began to die out with distance..
‘The course of one stream appears to have been determined to some
extent by the Snowdown disturbance, and it appears to have selected
the Oxford Clay outcrop for some distance in preference to the
harder Corallian limestones. Similarly, the more westerly stream
appears to have selected the outcrop of the Kimmeridge Clay, and
the erosion of the later Jurassics from the Dover area was doubtless.
due to its agency.
It is interesting to consider the nature of the Wealden sediments
in the light of the information afforded by the map. Mr. Lamplugh,
in the Survey memoir,! has expressed the opinion that the Wealden
section in the Dover shafts offers strong indication of the inflowing
of a river from the north-east. The present map shows the correct-
ness of this view. He expresses surprise, however, at the seeming
lack of Mesozoic material among the Wealden sediments, in view of
the fact that such a river must have crossed an area of ancient
1 Lamplugh, loc. cit.
Cretaceous and Older Rocks in East Kent. 5AT
quartz-veined rocks ringed round by Mesozoic formations. A little
consideration will now show that such a seeming absence of Mesozoic
débris need occasion no surprise. That the river must have flowed
over bare Paleozoic rocks during by far the greater part of its course
is quite obvious, for this area of bare Paleozoic extended (in
Wealden times) as far to the south-west as Walmestone and Deal,
and the river did not arrive at the neighbouring Mesozoic area until
it had attained its lower reaches. Nevertheless this apparent
absence of Mesozoic material from the Wealden sediments can be
English Miles
c°) 4 2 3
bt Isopachyte -Sysfem
Wealden . Easf Kenf .
By H.A.BAKER,B.Sc.,f.GS.
Fic. 2.
only aseeming one. Mesozoic débris must be there, but its presence is
doubtless masked by the preponderance of the ancient quartzose rocks.
The river must have possessed greater velocity during the earlier
part of Wealden times, in view of the steady movement of sub-
mergence which was taking place, and from the character of the
Hastings Beds in East Kent it can be seen that the abrading and
transporting power of the stream in this area must have been con-
siderable, only the coarser portion of its burden haying been deposited
548
Herbert A. Baker—Unconformity between
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Cretaceous and Older Rocks in East Kent. 549
here. The finer portion must have been dropped further on in its
course. Possessed of this corrasive power in Kast Kent, erosion of
the Mesozoic area of its bed must have been inevitable, but doubtless
the finer part of the eroded material was carried beyond the area.
Rarity of Mesozoic débris is therefore to be expected in the Wealden
of East Kent, and where Mesozoic fragments do occur they are
probably of large size and marked angularity. Comparison of the
details yielded by some of the borings suggests that the Mesozoics in
Kast Kent underwent erosion in early Wealden times, although it
must be borne in mind that allowance must be made for the general
pre-Cretaceous denudation of the area. For example, the sites of
the Tilmanstone shaft and the Barfreston boring both lie on the sub-
Cretaceous outcrop of the Oxfordian, and since Tilmanstone lies
a little to the north-east of Barfreston we should expect the thickness
of Oxfordian passed through to be rather less there. In actuality,
only 3 feet of Oxford Clay remain at Tilmanstone, whereas 102 feet
were passed through in the Barfreston bore. It would appear, then,
that the early Cretaceous strike-stream which traversed the outcrop
of the Oxford Clay in the neighbourhood of Tilmanstone was
responsible for a considerable amount of erosion.
With continued submergence Weald Clay times approached, and
delta conditions, ushering in the marine invasion of the Lower
Greensand, began to prevail. The waters of the Wealden lake
encroached northward upon Kast Kent, the velocity of the streams
was checked, finer sediments began to be deposited in quantity, and
base-level conditions were realized. The spreading waters united
the streams into a single sheet. The evidence shows that the main
stream and its two subsequent branches had become united into
a single sheet of water before the commencement of Weald Clay
times. Higher ground, separating the two subsequent streams from
each other, appears to have existed in the neighbourhood of Fred-
ville, yet 283 feet of Hastings Beds occur here. To the north-east,
however, the velocity of the stream still remained such that
deposition had not yet commenced. Probably in this area the
stream was active in removing from the Paleozoic floor some of its
Bathonian covering. With the advent of Weald Clay times, how-
ever, deposition proceeded over the whole area under water, and the
surface so long exposed to denudation was finally buried. In the
neighbourhood of Deal a small area of Coal-measures remained
uncovered until Lower Greensand times, and at and near Stodmarsh
an area of Bathonian remained until Gault times.
Norr.—After the proofs of this paper had been sent to the Editor
additional information became available in consequence of the
publication of the Summary of Progress of the Geological Survey
for 1916 (Mem. Geol. Surv. 1917). Details concerning three
additional borings (J. Pringle, Appendix II), viz., at Bere Farm
(12 miles north-east of Dover), Elham (close to Elham Station), and
Folkestone, are now to hand. The Bere Farm boring shows the
sub-Cretaceous surface there to be composed of Corallian Limestone,
as was expected, although the thickness of the Wealden (42 feet) is
550 Reports & Proceedings—The Royal Society.
less than might have been expected. The Elham and Folkestone
borings show the south-westerly thickening of the Wealden (158 feet
and 218 feet respectively), but each apparently demonstrates the
entire absence of both Purbeck and Portland rocks.
Mr. G. W. Lamplugh (Appendix IV) discusses the underground
range of the Jurassic and Lower Cretaceous rocks in East Kent, and
is more fortunately situated than the present writer (who has been
away at sea) in having information furnished by a further twelve
borings to work upon.
November 14, 1917.
REPORTS AND PROCHEDIN GS.
I.—Tue Royat Socrery.
November 8,1917.—Sir J. J. Thomson, O.M., President, in the Chair.
The following paper was read :—
‘The Structure, Evolution, and Origin of the Amphibia. Part I:
The ‘Orders’ Rachitomi and Stereospondyli.”” By D. M. S. Watson,
M.Se., Lieut. R.N.V.R. (Communicated by Professor J. P. Hill,
F.R.S.
In dis paper all known genera of Rachitomous and Stereo-
spondylous Stegocephalia are reviewed, the brain-case and basi-cranial
region, hitherto practically unknown, being described more or less
completely, and much new information about other regions set down.
It is shown that there are a series of characters which change
steadily with time in all Labyrinthodontia. The more important of
these changes are—
1. The gradual reduction and final loss of basi-oecipital, basi-
sphenoid, and supra-occipital bones and cartilages.
2. The gradual replacements of basi-pterygoid processes of the
basi-sphenoid by expansions of the para-sphenoid, and finally of the
ex-occipitals with which the pterygoids articulate.
3. The gradual increase in size of the inter-pterygoid vacuities,
and of the para-sphenoidal rostrum.
4. The gradual regression and final disappearance from the skull
of a foramen for the hypoglossal nerve.
It is pointed out that these characters, which are seen to arise
within these two groups, are those which have always been regarded
as the diagnostic features of the class Amphibia, and that it is certain
that they have arisen independently in at least three great orders.
Finally, it is shown that a hypothetical ancestor of the Rachitomi
obtained by projecting backward the evolutionary trends shown in
these and other series of characters which change regularly with
time, is actually realized in the Embolomerous Amphibian Péeroplax.
Il.—Geroxrocicatn Socrery or Lonpon.
November 7, 1917.—Dr. Alfred Harker, F.R.S., President, in the
Chair.
The following is an abstract of a lecture on ‘‘ The Nimrud Crater
in parish Armenia’! delivered by Felix Oswald, B.A., D.Sc.,
F.G.S. :
Reports & Proceedings—Geological Society of London. 551
The Nimrud volcano, one of the largest volcanic craters in the
world, is situated on the western shore of Lake Van, and was
surveyed and investigated geologically for the first time by the
speaker in 1898. The western half of the crater is occupied by
a deep lake of fresh water, while the eastern half is composed of
recent augite-rhyolites, partly cloaked in white voleanic ash. The
crater wall is highest on the. north (9,908 feet), rising in abrupt
precipices over 2,000 feet above the lake (7,653 feet). The southern
wall is also precipitous, but only reaches the height of 9,434 feet
(the south-eastern part). A large slice of the crater wall has slipped
down on the south-west, so as to form a narrow shelf, 800 feet above
the lake. The crater is nearly circular, 8,405 yards from west-south-
west to east-north-east, while the transverse axis 1s 7,905 yards.
The lowest points lie on the long axis, reaching only 8,139 feet on
the western and 8,148 feet on the eastern rim.
The crater wall has an external slope of 38° on the south and east,
where it consists exclusively of overlapping lenticular flows of augite-
rhyolite and obsidian. On the south-west, west, north-west, and
north these are capped by thin sheets of cindery basalt which must
have possessed great fluidity, extending for many miles to form wide
plains of gentle slope and great fertility down to Lake Van on the
east and into the Plain of Mush on the west. ‘These basalt-flows
dammed up the north-east to south-west valley between the
Bendimahi and Bitlis Rivers, and thus brought Lake Van into being.
The history of the Nimrud volcano may be summarized as follows
from the speaker’ s observations :—
1. Its forerunner was the Kerkur Dagh on its southern flank—
a denuded mass of grey augite- trachyte, rising to 9,000 feet, and
crowned by many peaks. It was probably erupted in the Pliocene
Period, subsequently to the folding of the Armenian area, in which
the latest folded rocks are of Miocene (Helvetian—Tortonian) age,
occurring north of the Nimrud Dagh and consisting of limestones
. with corals (Cladocora articulata, Orbicella defrancei, ete.), Litho-
thamnion, Foraminifera (Lepidocycline Orbitordes, Amphistegina, etc.),
beds of Pecten (P. urmiensis, etc.) and of oysters (Alectry yonia virletr).
Nimrud and the other numerous volcanoes of Armenia came into
existence at a period when the sedimentary rocks could no longer be
folded, but were fractured along definite lines, and Nimrud is
situated on the great fracture transverse to the Armenian folds at
the apex of their bending round from the Antitauric (west-south-
west to east-north-east) to the Persian (north-west to south-east)
direction, and it also marks the point of intersection of this fracture
with a great north-east to north-west fracture (Caucasian direction),
which delimits on the south Lake Van and the faulted depression of
the Plain of Mush, abruptly cutting off the Tauric horst of pre-
Devonian marbles and mica-schists.
2. Numerous flows of augite-rhyolite built up the vast cone of the
Nimrud Dagh, and the increasing pressure on the central vent
became relieved by extrusions of augite-trachyte along radial
fissures, forming the present promontories of Kizvag, Zighag, and
Karmuch.
552 Correspondence—Professor W. W. Watts. ,
3. A presumably long period of inactivity was followed by violent
explosions destroying the summit of the cone, and from this crater
(smaller than the present one) vast lava-flows of a very fluid basalt
(crowded with phenocrysts of labradorite, pale-green augite, and
some olivine) flooded the country and filled up the Bitlis and
Akhlat valleys, which have since then been eroded a little below
their former depth. The Sheikh Ora crater of basic tuff (now
breached by Lake Van) probably belongs to this period.
4. Further explosions widened the crater, in which a large lake
was formed, while the eastern half of the crater became filled by
a succession of outflows of augite-rhyolite, in which numerous blow-
holes were drilled, bringing to the surface large blocks of basaltic
agglomerate and also affording sections showing the transition
downwards from obsidian, spherulitic obsidian, and spherulitic
rhyolite to banded augite-rhyolite (with sanidine and green augite in
a micropeecilitic ground-mass).
5. The last eruption was recorded in 1441 by a contemporary
Armenian chronicler, and resulted in the extrusion of a very viscous
augite-rhyolite along a north-to-south zone of weakness, both inside
the Nimrud crater, where it separated off part of the large lake to
form the shallow, so-called ‘“‘ hot lake’’, and also to the north of
Nimrud, where it rose up fissures and in a small crater.
6. A violent earthquake in 1881, which destroyed the village of
Teghurt, at the eastern base of the crater wall, was the last sign of
activity ; but earthquakes are still frequent in the Plain of Mush, at
the western foot of the Nimrud Dagh, and recent fault-searps are
clearly visible along the borders of this faulted depression.
The speaker mentioned that he had presented his model of the
crater to the Museum of Practical Geology (Jermyn Street) and the
rocks and slides to the British Museum (Natural History), where his
fossils from Armenia are already preserved.’
A short discussion followed, and the thanks of the Fellows present
were accorded to Dr. Oswald for his lecture.
CORRESPONDENCE.
ae
COAL IN THE SILURIAN AT PRESTEIGN.
Srr,—Mr. Cantrill’s article in tie November number of this
Magazine on the boring for coal in Silurian and Longmyndian rocks
at Presteign (pp. 481-92) is interesting in throwing light upon
one of the most flagrant examples of the ignoring of geological
evidence in exploits of this nature. As there must have been some
grounds for the impression in the locality that coal existed there,
1 Tantern-slides of many unpublished photographs and drawings of the
Nimrud crater and its surroundings, a model coloured geologically (scale,
1 inch =1 mile), and a series of rock-specimens and rock-sections were
exhibited by Dr. Oswald in illustration of his lecture. A Geological Survey
map of the Maclean Umtata district, Cape Province, Sheet 27, scale
3-75 miles = 1 inch, 1917 (presented by the Geological Survey of the Union of
South Africa), was also exhibited.
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Heol. Mag., 191
Obttuary—Professor Edward Hull. 5538
without which local money probably would not have been forth-
coming, I may mention that on a visit to the section last August, with
Professor Garwood (whose excellent conjoint paper with Miss Good-
year, read at the Geological Society on June 6, and published in
abstract in the Proceedings on June 13, 1917, has been overlooked
by Mr. Cantrill in his account of work on the district), we learnt
from an old quarryman, whose memory reached back many years,
_ that it had been the custom in slack times to cart coal from the Clee
Hills for lime-burning. In order to preserve the coal it was necessary
to bury it, often in considerable quantities. Relics of these hoards
are occasionally met with, and, as their history has been generally
forgotten, it is very likely that these chance finds gave rise to the
idea that coal-bearing beds exist in the locality.
W. W. Warts.
HILLSIDE, LANGLEY PARK,
SUTTON, SURREY.
November 12, 1917.
(Gy SCA GFN ASyE SS
PROFESSOR EDWARD HULL, F.R.S.
(WITH A PORTRAIT, PLATE XXXYV.)
Born MAy 21, 1829. DIED OCTOBER 18, 1917.
By the death of Edward Hull, in the 89th year of his age, another
of the links has been broken which connect the geologists of
to-day with those of the earlier half of last century. He was born
in Antrim, and came of a stock that had been settled in Ireland
for at least four generations. Educated at Trinity College, Dublin,
he took his degree in Arts there. It was there, also, that he was
_ Inspired with a strong bent towards geology by the prelections of
Professor Thomas Oldham. That eminent man gave him a letter
of recommendation to Sir Henry De la Beche, Director-General of
the Geological Survey, who without loss of time found a place for
him in 1850 on his staff. From the time when Hull began field-work
by running sections in North Wales under J. B. Jukes, he continued
for seventeen years to be employed in England, first mapping tracts
in Gloucestershire and the upper parts of the Thames Valley, and
then in the coal-fields of Cheshire and Lancashire. During the
winter months, when the members of the staff, quitting the field,
repaired to London for indoor work in the office, Hull gained the
good-will of his colleagues by his imperturbable good-nature, which,
in sport, they would sometimes tax to its utmost limit. But he
seemed never to bear any of them a grudge, taking it all as part of
the routine of Survey life. They came to recognize that beneath his
foibles of manner there lay a kindly heart, ever ready to respond to
kindness.
In 1867, on the separation of the Geological Survey of Scotland as
a special branch, Hull’s good service was rewarded by his being
554 Obituary—Professor Edward Hull.
appointed District Surveyor and second in command on the Scottish
branch. Stationed at Glasgow, he was entrusted with the mapping
of the Clyde coal-field. But he had not been more than two years
in this new sphere when he received further promotion by being
appointed to succeed Jukes as Director of the Geological Survey of
Ireland—a post which he continued to fill until he retired from
official life, after a service of forty years.
The Irish Directorship was by no means a bed of roses. The
staff included at least one fiery member, who, with characteristic
Irish contempt for the ruling power, began opposition before the
newly appointed official had set foot in Ireland, demanding that the
appointment should be cancelled. When this demand was rejected,
he commenced the same system of petty insubordination and
opposition which had reduced poor Jukes to despair. Hull,
however, as an Irishman, was probably not wholly unaccustomed
to such tactics. He never succeeded in permanently silencing the
malcontent, and made many an appeal to his chief in Jermyn Street
for support. Indeed, no small part of his official correspondence
with headquarters consisted in reports of fresh and unexpected
devices of opposition. But his equanimity seemed never to be
seriously ruffled. No higher testimony to his essential good-nature
could be desired than the fact that he bore the perpetual worry. for
two and twenty years without losing either his wits or his temper.
During his reign in Ireland he had the opportunity of seeing the
geology of every part of the island. This wide experience gave him
material for the preparation of a convenient new general geological
map of the country on the scale of 8 miles to an inch. While
discharging his duties in the Survey he also held the Professorship
of Geology in the Royal College of Science in Dublin.
In 1891 Hull retired from official life. He was then little more
than 60 years of age, and still in full possession of health and
vigour. He determined to come to London and settle there in the
expectation that he might find congenial employment as a practical
geologist or geological engineer, especially in connexion with such
matters as coal-mining and water-supply, in which he had often been
consulted during his life on the Survey. He never allowed his pen
to rust. The list of his memoirs, papers, and separate books is
a monument of his industry. He was a voluminous writer on
English geology from the beginning of his life in the Survey
onwards. Some of his early papers are marked by a suggestiveness
in the discussion of more or less theoretical questions which gave
promise of distinction that was hardly fulfilled in his later work.
His best known volume, Zhe Coal-fields of Great Britain, is a useful
compendium of the subject of which it treats, and has passed through
five editions. Reference should also be made to his contributions to
our knowledge of the geology of Palestine. He was sent to that
country in 1883 by the Palestine Exploration Society, as leader of
an expedition which included the future Lord Kitchener as one
of its staff, the object of research being to report on the region of
Mount Seir, Sinai, and Western Palestine. In later years he
devoted much time to tracing on Admiralty and other charts the
Obituary—George O. Crick. | BBB
submarine continuations of the river-valleys of Western Europe and
Western Africa.
In 1910 the retired Professor published a thin autobiographical
volume, entitled Reminiscences of a Strenuous Life. His career, like
that of many other public servants, was quiet, uneventful, and
not unsuccessful. It included sufficient leisure for such work as
he chose to undertake, outside the sphere of his official duties, and
of this leisure he diligently availed himself in the preparation
of his contributions to the scientific literature of the time. Though
much of his writing may not be enduring, it must be admitted that
he has left his mark on the records of English geology. .
Those who knew Edward Hull best will always remember him as
a leal-hearted friend, who through a long life maintained the honour
of a gentleman and carried with him cheerfulness and good will
wherever he went.
ALG:
Norr.—On June 1, 1914, Professor Hull was one of those friends
who wrote and congratulated the Editor on the completion of fifty
years of the Gronogican Macaztne, and was indeed one of the four
famous geologists, then surviving, who had contributed to the 1864
volume of that journal, viz., the Rev. O. Fisher, M.A., F.G.S.;
Sir Archibald Geikie, O.M., K.C.B., P.Pres.R.S., etc.; Professor W.
Boyd Dawkins, M.A., D.Sc., F.R.S.; and Professor Hull, M.A.,
LL.D., F.R.S., etc., Professor Hull himself having during the fifty
years made 119 communications to this Magazine. We had pre-
pared a complete list of the titles of Hull’s books and papers,
amounting in all to over 250. Asa selected series had already been
published by Professor Hull at the end of his Reminiscences of a
Strenuous Life in 1910, and the full list would have occupied more
than ten pages, we could not devote so large a space in this number,
and the intention had therefore reluctantly to be abandoned.— Epitor
Grot. Mace.
GEORGE CHARLES CRICK.
BORN OCTOBER 9, 1856. DIED OCTOBER 18, 1917.
Born at Bedford on October 9, 1856, the son of Dr. F. W. Crick of
that town, George Charles Crick was educated at the Modern School
there. Subsequently he passed through a course of studies at the
Royal School of Mines, South Kensington, from 1875 to 1881. His
career there was noteworthy, for he successively. passed 1st Class in
Physics (1875-6), 1st Class in Biology (1876-7), 2nd Class in
Chemistry (1877-8), 1st Class in Geology (1878-9), 1st Class
in Mechanics, 2nd Class in Mineralogy, 2nd Class in Paleontology
(1879-80), and 1st Class in Mechanical Drawing (1880-1), thus
winning the Associateship.
For some short time he acted as one of the curators to a notorious
private collector, but on January 1, 1881, he entered on duty as
Clerk and Assistant Secretary to ‘‘H.M. Commission to enquire into
Accidents in Mines, ete.’’, of which Sir Warington W. Smyth was
556 Obitwary—George C. Crick.
Chairman, and he continued to actin that capacity till the termination
of the Commission in 1886.
Meantime in November, 1881, he undertook work in a voluntary
capacity in the Geological Department of the British Museum
(Natural History), and was then employed as a temporary Assistant
in 1882; on April 19, 1886, he was taken on the establishment as
an Assistant of the Second Class.
At the Museum he was given charge of the Fossil Cephalopoda,
then much in need of attention, and throwing his whole heart into
the work has left it one of the best arranged and indexed collections
in the institution.
This group was at that time in process of being catalogued by
Mr. A. H. Foord, who writes as follows: ‘(I had the happiness
of knowing the late Mr. G. C. Crick for many years, as I was
intimately associated with him in the Geological Department of the
British Museum. Our work running on similar lines we wrote
several papers jointly for this Magazine and for the Annals and
Magazine of Natural History. Great patience and minute attention
to details were conspicuous in all his work, and his researches were
therefore highly valued by students of paleontology in the branch
which he made his own, viz. the Belemnites and the Ammonites.
He will be greatly missed by all his colleagues.” Crick further
assisted Foord largely with the first two volumes of the Catalogue
of Fossil Cephalopoda in the British Museum, issued in 1888 and
1891, and was joint author with Foord of the third volume
(Bactrites and Ammonoidea, pars), published in 1897: whilst he
compiled the List of Types and Figured Specimens of Fossil Cephalo-
poda in the British Museum (Natural History), which saw the ight
in 1898,
Sixty-seven papers, including seven written in association with
A. H.Foord, and one with R. Bullen Newton, stand to Crick’s credit in
various scientific publications. In the course of these, seventy-four
new species are described and three new genera founded (_Amphoreopsis,
Styracoteuthis, and Belemnocamaz). Thisis quite a moderate number
for any student of fossil Cephalopoda, but his inclinations were ever
toward the morphological side of his subject, and especially any
feature of mechanical interest. This is very evident in his beauti- —
fully constructed model of the Ascoceras shell, and of the guard and
phragmocone of the Belemnite, as well as in the question of the
attachment of the animal to its shell in Nautiloids and Ammonoids.
The first instalment of his memoir on this last question, that dealing
with the Ammonoidea, was brought before the Linnean Society of
London in 1898, and appeared in their Transactions. This important
communication was very highly esteemed, and led, in conjunction
with his other work, to the award by the Geological Society in 1900
of a moiety of the Barlow-Jameson Fund. The second part of the
memoir, that treating of the Nautiloidea, was practically complete at
the time of his death, and it is hoped that, with other of his literary
remains, this may yet be published. Indeed, it would have appeared
before had it not been for the meticulous care he bestowed on all his
writings, which led him to withhold them from publication until
Obituary—George C. Crick. ee:
satisfied that the last possible item of information had been obtained,
whilst a contributing cause of delay was to be found in the state of
his health.
Never robust, he became on more than one occasion so seriously ill
that his life was despaired of; still, he made marvellous recovery,
and for some years had been so much better that he even participated
for a time in Red Cross work. Whilst conscious himself of his
precarious condition, he happily had no premonition of his sudden
end, and the afternoon before was discussing with Dr. Kitson the
geological age of some Ammonites from Nigeria, and making plans
for future work. ‘The following morning he passed quietly away at
his Wimbledon home, and a few days later was interred at Luton.
Modest, quiet, and unassuming, ever ready to assist others, Crick
endeared himself to all with whom he came in contact; even one
who had not seen much of him writes ‘‘he always seemed a lovable
little man”’. As such he will be sincerely mourned, not only by his
widow, but by a very wide circle of friends.
Crick was elected a Fellow of the Geological Society in 1881; he
joined the Geologists’ Association in 1887; was one of the original
members of the Malacological Society of London on its foundation in
1898; was elected a Fellow of the Zoological Society in 1896; and
of the Royal Geographical Society in 1916. He was also a member
of the Bedfordshire Natural History Society, of which his father was
one of the founders, and frequently read papers before them.
B. B. Woopwarp.
LIST OF THE SCIENTIFIC WRITINGS OF G. C. CRICK.
1889. (In association with A. H. Foord.) ‘‘On the Muscular Impressions of
Celonautilus cariniformis, J. de C. Sowerby, sp., compared with
those of the Recent Nawtilus’’: GHou. MaG., Dec. III, Vol. VI,
pp. 494-8, 2 woodcuts.
1890. (In association with A. H. Foord.) ‘*‘On the Muscular Impressions of
some Species of Carboniferous and Jurassic Nautiloids compared
with those of the Recent Nawtilus’’: Ann. Mag. Nat. Hist., ser. VI,
vol. vy, pp. 220-4, 6 text-figs.
(In association with A. H. Foord.) ‘‘Descriptions of new and
imperfectly defined species of Jurassic Nautili contained in the
British Museum (Natural History) ’’: ibid., pp. 265-91, 18 text-figs.
(In association with A. H. Foord.) *‘On some new and imperfectly
defined species of Jurassic, Cretaceous, and Tertiary Nautili con-
tained in the British Museum (Natural History)’’: ibid., pp. 388-
409, 9 text-figs.
1893. (In association with A. H. Foord.) ‘‘On a New Species of Discites
(Discites Hibernicus) from the Lower Carboniferous Limestone of
Treland’’: Grou. MaG., Dec. III, Vol. X, pp. 251-4, woodcut.
1894. (In association with A. H. Foord.) “‘ On the Identity of Hllipsolites
compressus, J. Sowerby, with Ammonites Henslowi, J. Sowerby” :
ibid., Dec. IV, Vol. I, pp. 11-17, pl.
(In association with A. H. Foord.) ‘‘On the Temnocheilus coronatus,
M‘Coy, from the Carboniferous Limestone of Stebden Hill, near
Cracoe, Yorkshire ’’: ibid., pp. 295-8, woodcut.
‘©On a Collection of Jurassic Cephalopoda from Western Australia—
obtained by Harry Page Woodward, F.G.S., Government Geologist—
with Descriptions of the Species’’: ibid., pp. 385-93 and 433-41,
Pls. XII and XIII.
558
1895.
1896.
1897.
1898.
1899.
1900.
1901.
1902.
1905.
‘
Obituar
ge C. Crick.
(Review.) ‘‘ Nanno, a new Cephalopodan type,’? by J. M. Clarke:
ibid,, pp. 561-2.
“Ona New Species of Prolecanites [P. similis] from the Carboniferous
Limestone of Haw Bank Tunnel, Skipton, Yorkshire’’: Trans.
Manchester Geol. Soc., vol. xxiii, pp. 80-8, 4 pls.
““Notes on some Fragments of Belemnites from Somaliland ’’: Grou.
MAG., Dec. IV, Vol. III, pp. 296-8.
“On Goniatites evolutus (Phillips) and Nautilus elongatus (Phillips),
ete.’’: ibid., pp. 413-19.
‘On a Specimen of Coccoteuthis hastiformis, Rupp., sp., from the
Lithographic Stone, etc.’’: ibid., pp. 439-43, Pl. XIV.
““On the Aperture of a Baculite from the Lower Chalk of Chardstock,
Somerset ’’: Proc. Malac. Soc., vol. ii, pp. 77-80, text-figs.
‘On the Pro-ostracum of a Belemnite from the Upper Lias of Alderton,
Gloucestershire ’’: ibid., p. 117, pl. ix.
‘“On an example of Acanthotewthis speciosa, Miinster, from the Litho-
graphic Stone, Hichstadt, Bavaria’’: GEOL. MaG., Dec. IV,
Vol. IV, pp. 1-4, Pl. I and woodcut.
‘*On the Fossil Cephalopoda from Somaliland, collected by Dr. Donaldson
Smith ’’: Appendix F in Dr. Donaldson Smith’s Through Unknown
African Countries, pp. 426-9.
‘*On an example of Acanthoteuthis Ferussacii, Miinst., from the Litho-
graphie Stone of Solenhofen, Bavaria’’: Proc. Malac. Soc., vol. iii,
pt. i, pp. 57-60, pl. i, etc.
‘“On the Muscular Attachment of the Animal to its Shell in some
Fossil Cephalopoda (Ammonoidea)’’: Trans. Linn. Soc., ser. 11,
vol. vii, pt. iv, pp. 71-113, pls. xvii—xx.
‘* Descriptions of new and imperfectly known species of Nautilus, from
the Inferior Oolite, preserved in the British Museum (Nat. Hist.) ”’:
Proc. Malac. Soce., vol. iii, pt. iii, pp. 117-39, 15 illustrations.
‘On a deformed example of Hoplites twberculatus, Sby., from the
Gault of Folkestone’’: GHoL. MaG., Dec. IV, Vol. V, pp. 541-2,
text-fig.
‘Note on Ammonites euomphalus, Sharpe’’: ibid., Vol. VI, pp. 251-6,
text-figs.
‘“On some new or little-known Goniatites from the Carboniferous
Limestone of Ireland’’: Ann. Mag. Nat. Hist., ser. VII, vol. ili, .
pp. 429-54, text-figs.
‘‘Notes on the Fossils from the Chilian Andes, collected by Mr. Fitz-
gerald’s Expedition’’: Appendix B in E. A. Fitzgerald’s The
Highest Andes, pp. 333-7.
‘‘Note on Ammonites calcar, Zieten’’?: GHoL. MAG., Dec. IV, Vol. VI,
pp. 554-8, text-figs.
“On the Horizon and Locality of Nawtilus truncatus, Sowerby ”’ :
ibid., Vol. VII, p. 154.
‘‘Note on Nautilus (Hphippioceras) clitellariwm, Sowerby’’: ibid.,
. 560.
Ne Note on Zieten’s type-specimens of Ammonites polygonius and Amm.
discoides’’: ibid., p. 561.
‘*A Chalk Ammonite, probably A. Ramsayanus, Sharpe’’: ibid.,
Vol. VIII, pp. 251-3.
“Note on a Dibranchiate Cephalopod from the London Clay of
Sheppey’’: Proc. Malac. Soc., vol. iv, pp. 256-8.
‘On the type-specimen of Belemnoteuthis montefioret, J. Buckman ”’
ibid., vol. v, pp. 13-16, pl. i.
Mh WNdditional Note on Ammonites calcar, Zieten’’: GEOL. MAG.,
Dec. IV. Vol. IX, p. 47.
‘‘Note on the genus 7megoceras, Hyatt’: ibid., pp. 127-8.
‘‘Note on Nautilus robustus, Fcord & Crick’’: ibid., pp. 342-6.
‘‘Note on Dr. J. E. Gray’s type-specimens of Jurassic Ammonites from
India”’: Proc. Malac. Soc., vol. v, pp. 285-9.
1904.
1905.
1906.
1907.
1908.
1909.
1910.
1911.
1915.
md
Obituary— George C. Crick. 559
“On Ammonites robustus (R. Strachey, MS.), H. F. Blanford, from
the Himalayas’’: ibid., pp. 290-5, text-fig.
““Notes on some specimens of straight-shelled Nautiloidea, collected by
the Rev. Samuel Couling, M.A., Ching Chow fu, Kiachow, North
China ’’: GEOL. MAG., Dec. IV, Vol. X, pp. 481-5, Pl. XXII.
““Note on Vestinautilus crassimarginatus, A. H. Foord’’: ibid.,
pp. 552-5.
“Note on Pericyclus fasciculatus, F. M‘Coy, sp.’’: ibid., Dec. V,
Vol. I, pp. 27-33.
**Notes on the Cephalopoda belonging to the Strachey Collection from
the Himalaya’’: ibid., pp. 61-70, 115-24.
‘‘Note on a remarkable Belemnoid from the Chalk of Flamborough
Head’’: Proc. Geol. Assoc., vol. xviii, pp. 283-5, figs.
“‘Note on Actinocamaz, Miller ; its identity with Atractilites, Link.”’:
GEOL. MAG., Dec. V, Vol. I, pp. 407-10.
‘Note on two Cephalopods obtained by Lieut.-Col. Skinner, R.A.M.C..,
from the Valley of the Tochi River on the N.W. Frontier of India’’:
ibid., pp. 490-3.
‘“ Description. of a Nautiloid, Plewronautilus pulcher, n.sp., from the
Carboniferous Rocks of England’’: Proc. Malac. Soc., vol. vi,
pp. 15-20, pl. i.
‘“On a new form of Carboniferous Nautiloid (Amphoreopsis pauct-
camerata) from the Isle of Man’’: ibid., pp. 134-7, pl. viii.
‘‘On a Dibranchiate Cephalopod, Styracoteuthis orientalis, n.gen. and
n.sp., from the Hocene of Arabia’’: ibid., pp. 274-8.
**Qn a specimen of Cyrtoceras (Meloceras) apicale [Foord] from the
Carboniferous Limestone, Kniveton, Derbyshire’’: GEOL. MAG.,
Dec. V, Vol. II, pp. 62-5.
“On some Fossil Cephalopoda from North Cornwall, collected by
Mr. Howard Fox, F.G.S.’’: ibid., pp. 154-60.
‘‘Note on a rare form of Actinocamaz (A. grossouvrei) [Janet] from the
Chalk of Yorkshire’’ : Naturalist, pp. 155-8, pl. xvi.
‘‘ Cretaceous Fossils of Natal’?: Third Report Geol. Surv. Natal,
pp. 163-250, pls. x—xv.
“‘The Cretaceous Rocks of Natal and Zululand and their Cephalopod
Fauna ’’: Grou. MaG., Dec. V, Vol. IV, pp. 339-47.
‘‘Note on two rare forms of Actinocamax from the English Upper
Chalk ’’: ibid., pp. 389-95.
‘On the Arms of the Belemnite’’: Proc. Malac. Soc., vol. vii,
pp. 269-79, pl. xxiii.
(In association with R. Bullen Newton.) ‘‘On some Jurassic Mollusca
from Arabia’’: Ann. Mag. Nat. Hist., ser. VII, vol. ii, pp. 1-29,
Is. i-ili.
ue ee on two Cephalopods collected by Dr. A. P. Young on the
Tarntaler Képfe, in Tyrol’’?: Grou. Mac., Dec. V, Vol. VI,
pp. 443-6, Pl. XXVI.
‘*On Belemnocamax boweri, n.g. et sp.’’: Proe. Geol. Assoc., vol. xxi,
pp. 360-5, pl. xxviii.
‘“Note on two Cephalopods from the Chalk of Lincolnshire ’’: GEOL.
MaG., Dec. V, Vol. VII, pp..345-8, Pl. XX VII.
‘“Note on the type-specimens of Ammonites cordatus and Ammonites
excavatus, J. Sowerby ’’: ibid., pp. 503-5.
‘‘ Snakestones’’?: Naturalist, pp. 145-6.
‘“Wotes on Carboniferous Cephalopoda from the neighbourhood of
Exeter’’: Quart. Journ. Geol. Soc., vol. ixvii, pp. 399-413.
“Note on Nautilus Mokattamensis, A. H. Foord, from the Eocene of
Egypt’’: Proc. Malac. Soc., vol. xi, pp. 286-90, pl. and text-figs.
‘On a Dibranchiate Cephalopod (Plesiotewthis) irom the Lithographic
Stone (Lower Kimmeridgian of Hichstaédt, Bavaria)’’: ibid.,
pp. 313-18, pl.
560 Miscellaneous.
1916. ‘‘Note on a gigantic Cephalopod Mandible’’: Grou. MaG., Dec. VI,
Vol. III, pp. 260-4.
‘“Note on the Carboniferous Goniatite Glyphioceras vesiculiferwm,
de Koninck, sp.’’: Proc. Malac. Soc., vol. xii, pp. 47-52.
“On Ammonitoceras tovilense [n.sp.] from the Lower Greensand
(Aptian) of Kent’’: ibid., pp. 118-20, pl. vi.
1917. ‘‘Note on the type-specimen of Crioceratites bowerbankwi, J. de C.
Sowerby ’’: ibid., pp. 138-9, pl. vii.
““ Recent Researches on the Belemnite Animal’’: Abstr. Proc. Geol.
Soc., Sess. 1916-17, pp. 12-13.
MISCHLUANHOUS-
Tuer Roya Soctery Mrpats: Awarps For Screntiric ResEARCH.—
Of the two Royal Medals to be awarded this year by the President
and Council of the Royal Society, the King has approved of one
being awarded to Dr. John Aitken, F.R.S., for researches in cloudy
condensations, and the other to Dr. Arthur Smith Woodward,
F.R.S., F.L.S., V.P.G.S., Keeper of the Department of Geology in
the British Museum (Natural History), and one of the Kditors of the
GrotoaicaL Magazine, for his researches in Vertebrate Paleontology.
We offer him our hearty congratulations on this well-merited honour.
For his life and portrait see Grot. Mae. 1915, pp. 1-5, Pl. I.
Tue WoopwaRrpIAN Proressor oF GEOLOGY IN THE UNIVERSITY
or Campriper.—This Chair, founded by Dr. John Woodward in
1722, and rendered illustrious by Professor Adam Sedgwick, who
held it from 1818 till 1872, when he was succeeded so happily by
one of his former pupils, Professor T. McKenny Hughes (1873-
1917), is now followed by another well-known Cambridge geologist,
John Edward Marr, Sc.D., F.R.S., who for thirty years or more has
fulfilled the important post. of University Lecturer in Geology and
College Lecturer in St. John’s. This election by the Senate has
been received with great satisfaction not only by University men
but by geologists at large, amongst whom Professor Marr is well
known and universally esteemed. A sketch of his life and work,
with a portrait, as an ‘‘ Eminent Living Geologist”’, appeared in this
journal in July, 1916 (pp. 289-95, Pl. XI).
Lennam Bens anp MiocenE Rock From tHE North SEA.—
Mr. R. B. Newton, who recently described these interesting deposits
in the Journal of Conchology, xv, 1916-17 (Guou. Mae., June, July,
1917), and Quart. Journ. Geol. Soc., Ixxii, 1916, respectively, has
now arranged a temporary exhibition series of the two faunas.
Those interested can see these specimens in the Gallery of Fossil
Mollusea at the British Museum (Natural History), on request,
during the next few months.
INDEX.
CLISINA and Aclisoides, 287.
Alaria Suteri, sp. nov., C. T.
Trechmann, 304.
Albite-Granophyre and Quartz-Por-
phyry, Carrock Fell, 403.
Alexandrian Rock, N.E. Illinois, 135.
Algal Development in Woolhope Lime-
stone, 331.
Alkaline Rocks, S.W. Afriea, S. J.
Shand, 235.
Ambrym Island, Volcanic Eruption
(1913), 496, 529 ; Eruption of, 1894,
531.
Amethyst, Colour of, 521.
Ammonite Septum, Development and
Morphology, 231.
Analcite and Analcitization, 287.
Aplustrum (?) Selwynensis, sp. nov.,
C. T. Trechmann, 337.
Apractocleidus teretepes, 29.
Arcas of Atlantic Slope, 224.
Atlantis, 473.
Auchenia lama, 516.
Australia, Geology of Northern Terri-
tory, 134.
South, 329.
—— West, 427, 428.
AILEY, E. B., Ben Nevis and
Glen Coe, 30.
Baker, H. A., London Basin and
Adjoining Areas, 91; Charnian
Movement, EH. Kent, 398; Uncon-
formity between Cretaceous and
Older Rocks in East Kent, 542.
Ball, J., West-Central Sinai, 80.
Ball, L. C., Wolfram Mines, N.
Queensland, 524.
Balsillie, D., Geology of Kinkill Ness,
Fife, 525.
“Banket,’’ The, 285.
Barrell, J., Origin of Tertiary Ape
Man, 424.
Base of the Camerate Monocyclic
Crinoids, F. A. Bather, 206.
Bather, F. A., Base of the Camerate
Monocyclic Crinoids, 206; Salt
Weathering and Worm Borings,
526.
‘* Batholiths’’ of Haliburton, Ban-
croft Area, 286. _
Becker, G. F.,and Day, A. L., Linear
Force of Growing Crystals, 225.
Bedfordshire, Handbook, 518.
DECADE VI.—VOL. IV.—NO. XII.
Bell, A., Sub-Crag Boxstones, 407.
Bell, Robert, Obituary of, 334.
Ben Nevis and Glen Coe, Geology of,
30.
Berry, E. W., Flora of Alum Bluff
Formation, 226; Flora of Calvert
Formation, 284.
Bird, Giant Eocene, 469.
Blatchford, T., Mineral Resources,
Yilgarn Goldfield, 428.
Boxstones,Sub-Crag, Hast Anglia, 407.
Brachiopod, new, Poikilosakos, 212.
Bremner, A., ‘‘ Kettle-holes,’’ Aber-
deen, 142.
Bretz, J. He:
Oregon, 524.
British Association Proceedings, 371,
384.
Brown, C. Barrington, Obituary of,
235.
Brown, J. Coggin, Catalogue of
Meteorites, Calcutta. Museum, 219.
Brydone, R. M., Chalk Polyzoa, 50,
145, 492; Chalk Zone of Holaster
planus, 245.
Bryozoa of Paris Basin, 283.
South-West France, 282.
Primitive works on, 283.
Buccal Armature of Conulus albo-
galerus, 433.
Buckman, S.S., Jurassic Chronology,
332.
Bunter Pebble-Beds of Notts, 288.
Burton, R. C., Obituary of, 96.
Burton, T. H., Bunter Pebble-Beds,
288. s
Bury, H., Paleoliths of Farnham, 29.
Butler, G. M., Handbook of Minerals,
378.
Satsop Formation,
ALCITH in Silicified Wood, 476.
Caledonian Thrust Movement,
Norway, 130. .
Calvert Formation, Flora of, 284.
Cambrian Geology and Paleontology,
25.
Camerate Monocyclic Crinoids, Base
of, 206.
Canavari,. Mario, Dentition of Pty-
chodus, 224.
Cantrill, T. C.,
Presteign, 481.
Canu, F., Tertiary Cheilostome
Bryozoa, 282-4.
Coal-boring at
36
562
Carbonate Springs, Regna-Verin, 475.
Carboniferous Limestone, Leicester-
shire Coalfield, 228.
S. Wales Coalfield, 229.
Carnarvonshire, Geology of part of,
12, 75.
Cenomanian and Turonian Cheilo-
stome Polyzoa, 256.
Chalk Polyzoa, 50, 145, 492.
Chalk Zone of Holaster planus, Isle
of Wight, 245.
Chamberlin, T. C., Origin of Earth,
279.
Chambers, C. G., Bedfordshire, 518.
Characesw, from the Lower Headon
Beds, 42.
Charnian Movement, East Kent, 398.
Chrysostoma Selwynensis, sp. nov.,
C. T. Trechmann, 299.
Cil-y-Coed to St. Annes, Llanllyfni,
Geology of, 12, 75.
Cladoselache clarkz, Upper Devonian,
Ohio, U.S.A., 542.
Clapp, F. G., Petroleum and Gas
Resources, Canada, 36.
Clark, W. B., Obituary of, 432.
Classification of Igneous Rocks, A.
Holmes, 115.
Clyde Area, Tertiary Dykes of, 305,
350.
Coal-boring at Presteign,
shire, 481, 552.
Coalfield, Central Scotland, 426, 475.
Cockerell, T. W. A., New Tertiary
Insects, 329.
Cole, G. A. J.. Rhythmic Deposition
of Flint, 64.
Conacher, H. R. J., Oil-shales and
Torbanites, 93.
Conchological Features of Lenham
Sandstone, Kent, 259, 320.
Conulus albogqlerus, Buccal Arma-
ture of, 433.
Coolgardie and Kast Coolgardie, 428.
Copper Sulphide, Secondary Reactions
involved in Enrichment, 222.
Coprolites, Spiral, not Saurian but
Sharks, 541.
Coral Octotremacis, 9.
Corals, Rugose, 108.
Correlation and Chronology in Geology,
285.
Cretaceous Brachiopoda and Mollusca,
West Africa, 132.
Crabs from 8. Dakota, 225.
—— Gasteropoda, 471.
Mollusea, New Zealand, 294,337.
Polyzoa, New, 492.
—— Unconformity in Hast Kent with
Older Rocks, 542.
Radnor-
Index.
Cribrilina Bramfordensis, sp. nov.,
Brydone, 493.
galanthis, nom. nov., Brydone,
repleta, nom. noy., Brydone, 495.
Seafordensis, sp. nov., 51. ~
—— T-formis, sp.nov., Brydone, 493.
transita, sp. nov., Brydone, 492.
tumuliformis, sp. nov., 51.
Crick, G. C., Obituary of, 528, 555.
Crystals and Crystal Forces, 223.
Linear Force in Growing, 223.
AVISON, C., Eruption of Sakura-
jima (1914), 520.
Day, T. C., Igneous Intrusive near
Maebie Hill, 93.
Dean, B., Bibliography of Fishes, 428.
Deeley, R. M., Disturbed Gravels, 157.
Detrital Andalusite i in Cretaceous and
Eocene, 135.
Diatryma, Skeleton of Giant Bird,
469.
Diplodocus Carnegiet, suggested re-
construction, 356.
Discoides cylindricus,
Girdle of, 389.
Disturbed Gravels, R. M. Deeley, 157.
Dithyrocaris tricornis and D. testu-
dinea, Horizon of, 269.
Dixey, F., and Sibly, T. F., Car-
boniferous, S. Wales Coalfield, 229.
Douvillé, H., Cretaceous and Hocene
of Tibet, 429.
Drysdale, C. W., Ore Deposits, British
Columbia, 39.
Dunstones of Plymouth, 282.
Dupare et Grosset, Platiniferous De-
posits of Spain and Russia, 176.
et Tikanowitch, Pa of the
Urals, 178.
Perignathic
ARLY Man, 1.
Earth, Origin of, 279.
Earthquake in Marsica, Italy, 474.
East Kent, Charnian "Movement in,
398.
Unconformity between Greiner
and Older Rocks in, 542.
Easter Island, 138.
Eastman, ©. R., Fossil Fishes in
U.S. Nat. Mus., 223.
Echinoidea Holectypoida, 160, 196,
249, 342, 389, 433.
Economic Geology, 181.
Ellis, David, Jurassic Fossil Fungus,
102.
Eminent Living Geologists: Alfred
Harker, 289; Osborne, Professor
Henry Fairfield, 193.
Index.
Hoanthropus, 1.
Kocene Bird, Gigantic, 469.
Htchegoin Pliocene, Mid-California,
328.
fia. QO. C., Meteorites,
86
Fauna of Fernando, Los Angeles,
135.
Federated Malay States, 144, 447,
503.
Fishes, Bibliography of, 428.
Fissure Eruptions, 534.
Flett, J. S., Submarine Contours,
233; Swiney Geological Lectures,
514.
Flint, Rhythmic Deposition of, 64.
Floating Fen of Danube Delta, 133.
Flora of Alum Bluff Formation, 226.
Fox Hill Sandstones, 225.
Foraminiferal Limestone, New Guinea,
143.
Fossil Beetles, Florissant, Colorado,
379.
Fishes in U.S. Nat. Mus., 223.
—— Insects, American, 135.
Plants, Text-book, 516.
Foye, W. G., Magnetite Ores, Ontario,
286; Batholiths of Haliburton,
Ontario, 286.
Frater, M., Voleanic Eruption (1913),
Ambrym Island, 496.
Fungus, Jurassic Fossil, 102.
ARDINER, C. I., Silurian Inlier
of Usk, 472.
Garwood, KE. J., Algal Development
in Woolhope Limestone, 331.
’ Genotypes of some Polyzoan Genera,
169.
Geological Factors in War, 284.
Map, City of Dublin Area, 240.
Maps as a Record of Geological
Advance, 329, 380.
Society, Edinburgh, 41, 93, 142,
233, 525.
— —— Glasgow, 93.
—— ——~ J,jondon, 42, 43, 89, 91,138,
140, 182, 185, 227, 228, 229, 231,
287, 330, 331, 380.
—— Survey, Great Britain, Memoirs,
30, 180.
Scotland, Memoirs, 426,475.
==: South Australia, 329.
—— —— United States, 34, 40.
—— —— WestAustralia Reports,427,
428.
Geology, Textbook of, C. Schuchert,84.
at the Seat of War, 68.
Liverpool, 44, 137,234, 432.
563
Geology of Chitral, Gilgit, and Pamirs,
175.
of the Urals, 178.
Gilligan, A., Millstone Grit, York-
shire, 137.
Glacial Controversy, New Zealand,
241.
Glastonbury Lake- Village, 425.
Glossopteris Beds, Queensland, 135.
Goldschmidt, V. M., Caledonian Thrust
Movements, Norway, 130.
. Grand’ Eury, F. C., Obituary of, 528,
Graptolites, Peru, 92.
Gravels, Disturbed, 157.
Green, Upfield, Obituary of, 336.
Greenwood, H. W., Secondary Rutile,
Millstone Grit, 234.
Gregory, J. W., On the Coral . Octo-
tremacis, 9; Professor Loewinson-
Lessing, 95; Geological Factors in
War, 284; Volcanic Eruptions,
Ambrym, New Hebrides, 529.
|G Ree Oe es gen.nov., W.D.
Lang, 256.
arcuata, n.sp., W. D. Lang, 257.
Harmeri,n.sp., W.D. Lang, 257.
Harker, A., Eminent Living Geologists,
289.
Harris, G. D., The Atlantic Slope
Arcas, 224.
Harwood, H. F., Picrite from Mozam-
bique, 150.
Hawkes, L., Rock Stream in Iceland,
97; Post-Glacial Uplifts in Norway,
174.
Hawkins, H. L.; Morphology of
Echinoidea and Holectypoida, etc.,
160, 196, 249, 342, 389, 433;
Perignathic Girdle of Pygasteride,
342; Discoides cylindricus, 389 ;
Conulus albogalerus, 433.
Hayden, H. H., Geology of Chitral,
Gilgit, and Pamirs, 175.
Hebrides, New, Volcanic Eruption,
Ambrym, in 1913-14, 529; Earlier
History to 1894, 530; Eruption of
1894, 531.
Holaster planus, Isle of Wight, 245.
Holectypus, Apical System of, 249.
Holland’s reconstruction of Dzplo-
docus criticized, 356.
Holmes, A., Classification of Igneous
Rocks, 115; Picrite from Mozam-
bique, 150; Pre-Cambrian of
Mozambique, 380; Albite-Grano-
phyre and Quartz - Porphyry,
Carrock Fell, 403.
Hooley, R. W., Integument of Dino-
saurs, 145. :
564
Hopkinson, J., Address to British
Association Conference of Delegates,
371.
Hughes, E. W., Geology of N.W. Car-
narvonshire, 12, 75.
Hughes, I’. McKenny, Obituary of,
334.
Hull, Professor E., Obituary of, 528,
553.
Hume, W. F., Oilfields of Egypt, 5,
315.
Hutchinson, H. N., Reconstruction of
Diplodocus Carnegier, 356.
CELAND, East, A Rock Stream in,
ie
Ichthyosaurian Coprolites not Spiral,
540.
Igneous Intrusive Phenomena, Macbie
Hill, 93.
Igneous Rocks, Classification of, 115.
Iguanodont Dinosaurs, Integument of,
148.
Illing, V. C., on Dr. Walcott’s Cam-
brian Geology, 25.
Illinois, Fossil Invertebrates, 132.
Integument Iguanodont, R. W.
Hooley, 148.
Invertebrate Fauna, Oligocene, Georgia,
477.
EFFREYS, H., Compression of
Karth’s Crust in Cooling, 87;
Distributions of Meteoric Bodies in
Solar System, 222.
Johnson, R. H., Oil and Gas Pro-
duction, 38. i
Johnston, W. A., Late Pleistocene
Oscillations, Ottawa, 32.
Jurassic Chronology, Correlation of,
332.
Fossil Fungus, 102.
335.
Kent, Hast, Charnian Movement in,
298; Unconformity between Cre-
taceous and Older Rocks in, 542.
Kettle-holes, Aberdeen, 142.
Kinkell Ness, Fifeshire, 525.
Knowlton, F. H., Flora of Fox Hill
Sandstones, 225.
i ENNEDY, H. T., Obituary of,
ANG, W. D., Genotypes of Poly-
zoan Genera, 169; Cenomanian
and Turonian Cheilostome Polyzoa,
256.
Lapworth, C., Graptolites from Peru,
92.
Index.
Late Pleistocene Oscillations, Ottawa
Valley, 32.
Leeds, Alfred N., Obituary of, 478.
Lenham Sandstone, Conchological
Features of, 259, 320; Lenham
Fossils, Temporary Exhibition of,
560.
Lies, E.G., Allen, E. T., and Merwin,
H. H., Copper Sulphide Enrich-
ment, 222.
Liverpool Geological Society, 44, 137.
University Geological Chair, 432.
Loewinson - Lessing, Volcanoes of
Central Caucasus, 95.
London Basin and Adjoining Areas,
91.
Geological Society, 42, 43, 89,
91, 138, 140, 182, 185, 227, 228,
229, 231, 287, 330, 331, 380.
Longstaff, Aclisina and Aclisoides,
287.
Lower Carboniferous Flora at Gullane,
28.
Lower Devonian F'auna, United States,
179.
ACNAIR, P., Horizon of Dithyro-
caris, 269.
Magnesite Deposits, Quebec, 522.
Maitai Series, New Zealand, 53.
Mammalian Bones, London District,
422.
Man, Geological Theory of Origin,
424,
Mancini, E., Earthquake in Marsica,
474.
Marbles, British and Foreign, 328.
Marr, Dr. J. E., appointed to Chair
of Geology, Cambridge, 560.
Matthew, W.D., Skeleton of Diatryma,
469...
Membranipora bitubularis, sp. noy.,
50.
crateroides, sp. noy., 49. -
—— Gabina, sp. noy., Brydone, 494.
subcastrum, sp. noy., Brydone,
494.
teniata, sp. nov., 50.
Merrill, G. P., Cookeville and Whit-
field Meteoric Irons, 221.
Mesodon macropterus, 386.
Meteoric Bodies, Distribution in Solar
System, 222.
and other Rocks, etc., Western
Australia, 327.
Meteorites, Catalogue from Calcutta
Museum, 219.
Collection in United States
National Museum, 220. -
Tron, Cookeville, Whitfield, 221.
Index.
Meteorites, New, 478.
— Structure and Composition, 86.
Millstone Grit, Yorkshire, 137.
Mineral Production of Canada, 182.
Resources, British Empire, 514.
United States, 89.
Yilgarn and Southern Cross,
428.
’ Mineralogical Society, 141, 232, 431.
Minerals, Handbook of, 378.
Mollusks, Choctawhatchee Marl, 477.
Molybdenum, Natal, 475.
Morphology or Hchinoidea Holecty-
poida, 160, 196, 249, 342, 389, 433.
Mozambique, Picrite from, 150.
Murdoch, J., Opaque Minerals, 425.
EHRITOPSIS(?)Speighti, sp.nov.,
C. T. Trechmann, 300.
New Zealand, Age of Maitai Series,
aon
Cretaceous Mollusca, 294, 337.
Glacial Controversy, 241.
Newton, R.B., Cretaceous Brachiopoda
and Mollusca, W. Africa, 132;
Conchology of Lenham Sandstones,
Kent, 259, 320; Exhibition of
Lenham Fossils, 560.
Nomland, J. O., Htchegoin Pliocene,
California, 328.
BITUARY Notices: Bell, Dr. B.,
334; Brown, C. Barrington, 235,
241; Burton, R. C., 96; Clark,
W.B., 432; Crick, G. C., 528, 555 ;
Grand’EHury, F. C., 528; Green,
Upfield, 336; Hughes, T. McKenny,
334; Hull, Edward, 528, 553;
Kennedy, H. T., 335 ; Leeds, A.N.,
478; Reid, Clement, 47; Swain,
Ernest, 95; Tiddeman, Richard
Hill, 238; Tylor, Sir EB. B., 96;
Woodward, H. P., 239.
Octotremacis, Structure,
and Age, 9.
Oil and Gas Production, 38.
Oilfields of Egypt, 5, 315.
Oil-shales and Torbanites, 93.
Opaque Minerals, Microscopical De-
termination, 425.
Ore Deposits, Rossland,
Columbia, 39.
Oswald, Felix, The Nimrud Crater,
Turkish Armenia, 550.
Affinities,
British
AHANG Volcanic Series, Federated
Malay States, 447, 503.
Paleocene Bat, 516.
Palsoliths of Farnham, 29.
Paleontographical Society, 226.
565
Pallis, Marietta, Floating Fen of
Danube Delta, 133.
Parsons, L.-M., Carboniferous Lime-
stone, Leicestershire Coal-field, 228.
Perignathic Girdle of Pygasteride, 342.
Petroleum and Natural Gas Resources,
Canada, 36.
Picrite from Mozambique, Holmes and
Harwood, 150.
Piltdown Gravel, 227, 480.
Platiniferous Deposits of Spain and
Russia, 176.
Plectrodus, Jaw of, 74.
Pliocene Cave, Doves Hole, 480.
Poikilosakos, gen. et sp. noy., 212.
Polymorpiites, Genus, 442.
Polyzoa, New Chalk, 50, 145, 492.
Polyzoan Genera, Genotypes of, 169.
Post-EKocene and Post-Miocene, in
Oilfields, Egypt, 5.
Post-Glacial Uplifts in Norway, 174,
235.
Pre-Cambrian and Rocks of Mozam-
bique, 380.
Presteign, Radnorshire, Coal-boring
at, 481 ; Coal in Silurian at, 552.
Ptychodus, Dentition of, 224.
Pugnellus Marshalli, sp. noy., C. T.
Trechmann, 302.
Wawarensis, sp. nov., C. T.
Trechmann, 303.
Pyenodont Fishes, 385.
Pygasteride, Perignathic Girdle of 342.
UARTZ-PORPHYRY and Albite-
Granophyre, Carrock Fell, 403.
ADIOACTIVITY and Mountain
Building, 87.
Rathbun, Mary J., Cretaceous Crabs
from Dakota, 225.
Reid, Clement, Characer, Lower
Headon Beds, 42; Obituary of, 47.
Rhode Island Coal, 40.
Rhythmic Deposition of Flint, 64.
Rock Stream in East Iceland, 97.
Royal Society, London, 40, 550;
Award of Royal Medals, 550.
Royal Society Club, 476.
Rugby School Natural History Society,
329:
Rugose Corals, 108.
AKURA-JIMA Eruption (1914),
520.
Salt-weathering and supposed Worm-
borings, 526.
Samoa Earthquake and Tidal Wave,
432.
Satsop Formation, Oregon, 524.
566
Schuchert, C., Textbook of Geology,
84; Correlation and Chronology: in
Geology, 285.
Scott, Alexander, Primary Analcite,
287.
Scouler, Dr. John, Dithyrocaris tri-
cornis, Horizon of, 269.
Secondary Rutile Millstone Grit, 234.
Sederholm, J. J., Synantetic Minerals,
285.
Seward, A. C., Fossil Plants, 516.
Sharks’ Coprolites spirally formed,
541.
Shells of Holderness Basement Clays,
477.
Sheppard, T., British Geological
Maps, 329, 380.
Silurian Inlier of Usk, 472.
Simpson, HE. 8., W. Australian Rocks
and Meteorites, 327.
Sinai, West-Central, 80.
Smellie, W. R., Apractocleidus tere-
tepes, 29.
Smith, William, and his Maps, 380.
South African Geology, 326.
South Australia, Annual Report of
Government Geologist, 329.
—— Mining Operations, 523.
Spilitie Facies, Lower Carboniferous
Lava-flow, Derbyshire, 184.
Spirifer, Silurian, Maine, 135.
Stopes, M. C., Mesozoic Cycads, 89.
Strahan, A., Geology at Seat of War,
68.
Sub-Crag, ‘‘ Boxstones,’’ East Anglia,
407.
Submarine Contours, Orkney Islands,
233.
Swain, E., Obituary of, 95.
Swiney Lectures, Geology, 514.
Swinnerton, Professor H. H., Develop-
ment and Morphology of Ammonite
Septum, 231.
Synantetic Minerals, 285.
AYLOR, W., New Locality for
Triassic Reptiles, 41.
Termier, P., Atlantis, 473.
Tertiary Cheilostome Bryozoa, Ameri-
can, 282.
Dykes of the Clyde Area, 305,
350.
Insects, New, 329.
Tibetan Paleontology, 429.
Tiddeman, R. H., Obituary of, 238.
Titaniferous Magnetite Ores, Ontario,
286.
Trechmann, C. T.,
Zealand, 53;
Maitai Series, New
Glacial Controversy,
Index.
New Zealand, 241; Cretaceous
Mollusca, New Zealand, 294, 337.
Trench Geology, E. W. H., 431.
Trias of New Zealand, 182.
Triassic Crinoids from New Zealand,
3, 184.
Triassic Reptiles, New Locality, 41.
Trueman, A. E., Genus Polymor-
phites, 442.
Tungsten Deposits,
Rhodesia, 374.
Turonian Cheilostome Polyzoa, 256.
Tylopora, gen. nov., W. D. Lang, 257.
lorea, sp. nov., W. D. Lang, 258.
rowet, sp. noy., W. D. Lang, 258.
Tylor, Sir HE. B., Obituary of, 96.
Tyrrell, G. W., Tertiary Dykes of the
Clyde Area, 305, 350.
Essex Vale,
NCONFORMITY between Cre-
taceous and Older Rocks in East
Kent, 542.
United States Survey, 34, 40.
Upper Silurian Fish, Plectrodus, 74.
ENTS at Stromboli, 519.
Voleanic Eruption (1913-14),
Ambrym Island, 496, 529.
Necks in North-West Ayrshire,
4].
—— Series,
503.
Voleano, the Nimrud, on Lake Van,
Armenia, 550.
Pahang, F.M.S., 447,
ADE, B., Cretaceous Gastero-
poda, 471.
Wagner, P. A., South African Geology,
326.
Walcott, C. D., Cambrian Geology and
Palwontology, 25.
War, Geology at Seat of, 68. ;
Washington, H.S., VentsatStromboli,
519.
Watson, D. M. S., Poitbilosanas, a
new Brachiopod from Texas, 212;
Structure, Evolution, and Origin of
the Amphibia: the Rachitomi and
Stereospondyli, 550.
Watson, J., British and Foreign
Marbles, 328.
Watson, T. L., Colour of Amethyst,
521.
Watts, W. W., Coal in the Silurian
at Presteign, 552.
Wellington, New Zealand, Phil. Soc.,
46.
West-Central Sinai, Geology of, 80.
! Index.
Wherry, HE. T., Calcite in Silicified
Wood, 476.
Wickham, H. F., Fossil Beetles,
Colorado, 379.
Willbourn, E. 8., Pahang Volcanic
Series, 447, 503.
Williams, H. §., Lower Devonian
Fauna, United States, 179.
Wilson, G. V., Volcanic Necks, North-
West Ayrshire, 41.
Wilson, M. H., Magnesite Deposits,
Quebec, 522.
Wolfram Mines, North Queensland,
524. ,
Woodward, Arthur Smith, Award of
Royal Society Gold Medal to, 560;
Early Man, 1; Jaw of Plectrodus,
74; Piltdown Gravel, Second Skull
of Hoanthropus, 227; Pycnodont
Fishes, 385; Mammalian Bones,
London, 422; So-called Coprolites
of Ichthyosaurians and Labyrintho-
donts, 540; Hybodus, Acrodus,
567
Lias, Lyme, etc., 541; Clado
selache, Devonian, Ohio, 542.
Woodward, H. P., Obituary of, 239.
Woodwardian Chair of Geology in
Cambridge given to Dr. J. H. Marr,
F.R.S., 560.
Worth, R. H., Dunstones of Plymouth,
282.
Wright, F. E., Crystals and Crystal
Force, 223.
Wynne, HK. Hughes, Cil-y-Coed, 12,
75.
AKOVLEYV, N. W., Rugose Corals,
108.
Young, R. B., The Banket, 285.
EKALLEY, A. HE. V., Tungsten
- Deposits, Rhodesia, 374.
Zincand Lead Deposits, United States,
181.
Zoological Record, 380.
Zoological Society, London, 41, 288.
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