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Bind 23, nr. 14
Biol. Medd. Dan. Vid. Selsk. 23, no. 14 (1963)
THE LOWER MIDDLE CAMBRIAN
KALBY-LER (KALBY CLAY)
ON THE ISLAND OF BORNHOLM
BY
VALDEMAR POULSEN
København 1963
Kommissionær: Ejnar Munksgaard
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Biologiske Meddelelser
udgivet af
Det Kongelige Danske Videnskabernes Selskab
Bind 23, nr. 14
Biol. Medd. Dan. Vid.Selsk. 23, no. 14 (1963)
THE LOWER MIDDLE CAMBRIAN
KALBY-LER (KALBY CLAY)
ON THE ISLAND OF BORNHOLM
BY
VALDEMAR POULSEN
København 1963
K om m issionæ r: Ejnar Munksgaard
Synopsis
The Kalby-ler (Kalby clay) formation is a new name for the deposit previously
believed to be weathered Exsulans limestone, which belongs to the Triplagnostus
gibbus zone. The emendation is necessitated by evidence, which shows that the
clay belongs to the Tomagnostus fissiis — Ptychagnosius atavus zone. The evidence
is discussed, and the lower Middle Cambrian stratigraphy is revised. A tentative
account of the Lower and lower Middle Cambrian history and paleogeography is
presented.
P R IN T E D
B IA N C O
IN
DENM ARK
L U N O S B O G T R Y K K E R I A /S
Introduction
In 1942 C. P o u l s EN described several new fossils from the
M iddle C am b rian clay at L æ saa. T he fossils w ere o b tained by
élu triatio n of a lim ited q u an tity o f clay, an d therefore the p resen t
w riter a few y ears ago collected m ore m ateria l hoping to o b tain
ad d itions to the fa u n a. A part from the species rep o rted by
C. P o u l s EN the present w riter thus fo u n d several new species of
Stenothecopsis, Stenotheca ?, spicules o f Protospongia ?, eocystid
plates, an d p ro b lem ática. T he non-trilobite fa u n a elem ents, p ra c ­
tically all o f w hich p re su m a b ly are of Low er C am b rian age, will
be describ ed in a su b seq u en t p ap er. T he fossils in the clay com ­
prise L ow er a n d M iddle C am b rian elem ents. In the following
m ain ly the M iddle C am b rian trilobite m aterial will be discussed.
T he m aterial is in the collections of the M ineralogical an d
Geological M useum of the U niversity of C openhagen.
Summary of previous work
G r o n w a l l (1902 a) described the M iddle C am b rian sections
an d the fa u n a from the stream s Ø leaa an d L æ saa on the islan d of
B ornholm . At Ø leaa the Low er C am b rian B ispebjerg sandstone is
ov erlain by 25 centim etres of gray E xsulans lim estone. T he lim e­
stone is rich in grains of glauconite a n d pyrite, especially in the
low er p art. E q u ally conspicuous is the content of irre g u la r,
som ew hat ro u n d e d pebbles of p h osphoritic sandstone. T he lith o ­
logy of these pebbles corresponds to the u p p e r 40 centim etres o f
the un d erly in g B ispebjerg sandstone. Fossils, p re d o m in a n tly
trilobites, occur ab u n d a n tly in the E xsulans lim estone, especially
in the u p p e r p art. In the section at the stream L æ saa the B ispebjerg
san d sto n e is succeeded b y 15 centim etres of a gray clay, w hich is
4
Nr. 14
n o t too w ell exposed. G r o n w a l l rep o rted th a t m ost o f the clay
w as u n co n so lidated a n d soft, b u t co ntained h a rd e r lu m p s, w hich
show ed th a t the clay w as a re sid u a l deposit form ed by w eathering
of a fossiliferous lim estone. T he ca rb o n ate su pposedly w as
w ash ed aw ay. D eterm inable fragm ents o f fossils w ere not found.
T he clay w as fo u n d to be ric h in glauconite a n d pyrite, pebbles or
lu m p s o f p h o sphoritic sandstone, an d w ell-ro u n d ed q u artz grains
iden tical to those of the L ow er C am b rian R ispebjerg sandstone.
C onsidering the absence of d eterm in ab le fossils, th e agree­
m ent in lithology, the thickness, an d the position in the sequence
it is u n d e rsta n d a b le th at G r o n w a l l (1902 a, pp. 20 an d 32) co rre­
lated the clay at Lsesaa w ith the Exsulans lim estone at 01eaa. T he
deposits w ere re ferred to the low erm ost Ctenocephalus exsulans
sub zo n e o f the Paradoxides tessini stage. W h e n discussing the
S can d in av ia n Paradoxides beds G r o n w a l l (1902 b ) m ain tain ed
the co rrelatio n as m entioned above.
K aj H a n s e n (1937) m ad e a co m p ariso n betw een the Low er
C am b rian deposits in S cania a n d on B ornholm . H e called attention
to a p yritic lay er im m ediately above the clay at Lsesaa. T he
p y ritic layer, previously described by G r o n w a l l , is a 5 centi­
m etres th ick conglom erate w ith pebbles o f ph o sp h o ritic sandstone,
irre g u la r bodies o f phosphorite, a n d fragm ents of w eath ered
sed im en ts w ith traces of fossils. T he pebbles of ph o sp h o ritic
san d sto n e are identical to those fo u n d in the u nderlying clay.
Som e o f the ro ck fragm ents could be identified as belonging to the
L ow er C am b rian siltstone (»G reen shales«). T he pyrite form s the
m atrix of the conglom erate. K a .j H a n s e n correlated the pyritic
conglom erate w ith a som ew hat sim ilar layer occurring at one
locality at 01eaa. H ere, at H a n s e n ’s locality no. 6, the som ew hat
calcareo u s a n d glauconitic R ispebjerg sandstone is follow ed b y a
conglom erate lay er 10 centim etres in thickness. T he low er p a rt of
this lay er has a m atrix o f fine-grained phosp h o ritic a n d glauconitic
san d sto n e. T h e m atrix su rro u n d s ro u n d e d q u artz grains, p h o sp h o ­
ritic san d sto n e, a n d elongate lu m p s o f pjTite. T he u p p e r p a rt
p re d o m in a n tly consists of coarse q u artz grains em b ed d ed in a
m atrix of p h o sphorite an d pyrite. T he pyritic lay er at 01eaa is
follow ed by the E xsulans lim estone, an d , consequently, the clay at
Lsesaa, u n d erly ing the supposedly eq uivalent pyritic conglom erate.
N r. 14
5
w ould be older th a n the Exsulans lim estone. T hus K. H a n s e n
re ferred the clay at L æ saa to the L ow er C am b rian as an equ iv alen t
to the som ew hat calcareous an d glauconitic R ispebjerg sandstone
at locality no. 6. He concluded th a t the p rin c ip a l difference betw een
the beds at 01eaa a n d L æ saa w as that the clay at L æ saa was
uncon so lid ated . He fu rth e r stated th a t if the clay indeed w as the
resid u e of w eath ered E xsulans lim estone, one w ould expect the
lay er o f clay to be m u ch th in n er, th a n it actually is.
By élutriatio n of sam ples of the clay K. H a n s e n o b tain ed som e
b ra ch io p o d specim ens, w h ich w ere re ferred by C. P o u l s e n to
Acrotreta sagittalis ( S a l t e r ) a n d Acrotreta cf. eggegrundensis
W im a n . K. H a n s e n then, after com paring these species w ith the
k n o w n S can d in av ia n occurrences of the sam e species a n d th eir
associated fossils, re ferred the clay at L æ saa an d the calcareous
p a rt of th e R ispebjerg sandstone to the L ow er C am b rian Holm ia
kjerulfi zone or Streniiella linnarssoni zone. G r o n w a l l (1902)
w as o f the o p in io n th at the B ornholm section contained a hiatus
com prising these two late Low er C am b rian zones.
C. PouLSEN (1942) stated th a t the vertical range of Acrotreta
eggegrundensis w as u n k n o w n , a n d as Acrotreta sagittalis is
w idely d istrib u ted in the M iddle C am b rian , the two species w ere
accordingly of no v alue for the correlation. A ttem pting to o b tain
species, w h ich m ight be of stratig rap h ical relevance, C. P o u l s e n
h a d excavated ad d itio n al m ateria l of the clay for élu triatio n of
fossils. He m ad e a distinction betw een w o rn (ro lled ) a n d wellp reserv ed shell specim ens. T he w ell-preserved specim ens w ere
su p p o sed to be n o rm a l m em bers of the fa u n a of the clay, an d
w orn specim ens su p posedly h a d b een w ash ed out o f older deposits
to be em b ed d ed in the clay an d in the E xsulans lim estone. H ow ­
ever, the p resen t w riter in his co n siderably larger fossil m aterial
has observed w o rn as w ell as w ell-preserved specim ens of
H yolithellus an d other genera, and, consequently, the state of
p reserv atio n is of little or no value w ith re g ard to the d eterm in atio n
of the relative age of the fa u n a elem ents. A co m p ariso n of the nontrilobite fa u n a o f the clay w ith sim ilar fa u n as elsew here has
cau sed the p resen t w riter to believe th at the m ajority of the species
m u st be of L ow er C am b rian age.
W h en excavating the clay C. P o u l s e n succeeded in finding
N r. 14
6
fragm ents o f a relatively fresh an d h a rd lim estone containing
Jincella parva, Ctenocephalus exsiilaiis, a n d Holocephalina linnarssoni. As these species are w ell-know n from the E xsulans lim estone,
he follow ed G r o n w a l l in correlating this w ith the clay at L æ saa.
T he p resen t w riter m ay ad d th a t by etching sam ples o f the
E xsulans lim estone he has o b tained species listed from the clay.
T h u s the beds are in good agreem ent faunistically a n d lithologi­
cally.
C. PouLSEN co ncluded th a t the R ispebjerg sandstone, deposi­
ted at the tim e of the Holmia torelli zone, w as follow ed b y p re ­
su m ab ly th in deposits belonging to the H olm ia kjeriilfi zone or the
Strenuella linnarssoni zone. B oth zones m ight have b een developed,
b u t the beds m ost likely w ere th in a n d consequently re ad ily
rem o v ed by the erosion in the tim e in terv al corresponding to the
Eccaparadoxides oelandicus stage. T he n u m ero u s w o rn shells of
Acrofhele (^Redlichella) granúlala su pposedly in d icated th a t a
deposit co rresp o n d in g to the Acrothele granúlala conglom erate,
w h ich is the low erm ost b ed in the Paradoxides paradoxissim us
stage, once existed in the B ornholm area. C. P o u l s e n pointed out
th a t the specim ens of Acrolhele w ere quite free of adh erin g rock
particles. P ro b ab ly the deposit only existed a very sh o rt tim e a n d
w as eroded, before lithification could tak e place. He finally
co n clu d ed th a t in the tim e in terv al betw een the deposition of the
R ispebjerg san dstone an d the E xsulans lim estone the B ornholm
region w as alfected by two transgressions, the first o f w hich
o cc u rre d in the late Low er C am b rian , the second in the M iddle
C am brian.
The age of the Kalby-ler (Kalby clay)
W h e n restudying C. P o u l s e n ’s trilobite m ateria l from the
clay, the p resen t w riter noticed th a t all the specim ens w ere m olds
consisting o f a fine-grained, ph o sp h o ritic an d argillaceous sa n d ­
stone. T his type o f p reserv atio n does not occur in the E xsulans
lim estone, w h ere only ca rb o n ate exoskeletons are present. Also
the p resen t w rite r’s elutriated m ateria l contains m olds of frag­
m en tary cran id ia. E specially interesting is a co n sid erab ly w orn
agnostid cep h alo n (text-fig. 1).
Nr. 14
/
Fig. 1. Fragmentary cephalon of Plychagnostus atavus (MMH no. 9296), X 15.
From the Kalby clay at Lsesaa.
E ven if the b o rd e r a n d p a rt o f the posterior lobe of glabella
are m issing in the specim en (M M H no. 9296), it m ay safely be
re ferred to Plychagnostus atavus ( T u l l b e r g ). A co m p ariso n w ith
Sw edish species listed by W e st e r g a r d (1946) from the Triplagnostus gibbus zone (B 1), to w hich the E xsulans lim estone belongs,
show s th at the above m entioned specim en differs from the species
o f Peronopsis in the sh ap e of glabella a n d in the genal region being
corru g ated . T he specim en differs from Triplagnostus praecurrens
a n d T. gibbus in possessing a corrugated genal region. It show s
som e resem b lan ce to Tomagnostus fissus a n d T. cf. corrugatus, but
the an terio r glab ellar lobe in these species is su b q u a d ra te , cleft
in front by a sh o rt sagittal furrow , w hich for a short distance
continues into the p reg lab ellar field. T he B ornholm specim en has
a n an terio r glab ellar lobe tapering forw ard, an d a distinct sagittal
fu rro w crossing the preglabellar field, p re su m a b ly reaching
an terio r b o rd er.
None af the Sw edish species from the Eccaparadoxides oelandicus stage show an y resem b lan ce to the specim en fro m the clay.
T he low er alu m shale overlying the clay a n d the E xsulans lim e­
stone contains P lychagnostus atavus a n d H ypagnostus parvifrons
an d th u s belongs to the Tomagnostus fissus — P lychagnostus atavus
zone (B 2 ). A ccordingly, the w o rn specim en of necessity m ust
8
Nr. 14
belong to the low er p a rt of this zone, am ong the species o f w hich
only the in dex fossil P tychagnostus atavus b ea rs an y resem blance.
A co m p ariso n show s th a t the frag m en tary cep h alo n in all preserved
details, inclu d ing the p attern o f genal furrow s, is id en tical to this
species.
T he E xsulans lim estone th e n m ust be older th a n the clay,
w h ich the p resen t w riter p refers to reg ard as a sep arate form ation,
the K alby-ler form ation. See also text-fig. 2.
T he pyritic conglom erate overlying the clay m ust belong to the
sam e zone as the clay. T he pyrite in the m atrix m ost likely is of
later, epigenetic origin, the precip itatio n being d ep e n d an t u p o n
the p resence of a considerable am o u n t o f d etrital pyrite grains.
D eterm inable fossils have not b een found in this conglom erate.
The Kalby-ler formation
T y p e l o c a l i t y ; Section at the w estern b a n k of the stream
Lsesaa, B ornholm . T he section is situated 240 m etres southeast of
the fa rm K albygard. T his so far is the only k n o w n o ccu rren ce of
the K alby clay. T he thickness of the fo rm atio n am ounts to 15
centim etres. It is delim ited vertically b y the L ow er C am b rian
R ispebjerg san d sto n e an d the M iddle C am b rian p yritic co n ­
glom erate im m ediately below the low er alu m shale. Due to the dip
o f th e strata the outcrop is very sm all, situated close to the w aterlevel o f the stream .
S t r a t i g r a p h i c a l p o s i t i o n ; T he Tomagnostus fissiis — P tychag­
nostus atavus zone (B 2 ).
L i t h o l o g y ; T he gray K alby clay is extrem ely heterogeneous w ith
reg ard to com position of com ponents a n d g rain sizes. T he m aterial
m ay be identified as debris from L ow er a n d M iddle C am b rian
deposits a n d com prises fragm ents o f siltstone ( “ G reen sh a le s” ),
ro u n d e d q u artz grains an d ph o sp h o ritic pebbles from the R ispe­
bjerg san d sto n e, glauconite, pyrite, m uscovite. M iddle C am b rian
fine-grained sandstone o r siltstone, b ra ch io p o d fragm ents an d
tu b u la r fossils. A ccording to K. H.w s e n (1937) 60 “/o of th e
p articles are below 0,2 m m . in d iam eter, a n d this fractio n c o n ­
tain s 7 ,5 ^0 C alcium carbonate, possibly originating from the E x -
N r. 14
9
sulans lim estone. Most of the pyrite u n d o u b ted ly is of later origin.
T h ere is no evidence th a t the K alby clay sh o u ld be reg ard e d
as the resid u e of a d ecom posed lim estone. T he deposit p ro b a b ly
never w as su b jected to lithification. As m entioned earlier, the
solid, fossiliferous sam ples collected b y C. P o u l s e x consist of silt,
p ractically devoid of C alcium carbonate. T he p resen t w riter
unsuccessfully attem pted to o btain fresh o r only p artly decom posed
sam ples of a possible original lim estone. F u rth erm o re , the p re sen ­
ce of w ell-preserved eocystid plates consisting of C alcium carbona­
te in d icates th a t the sedim ent ca n only have b een influenced by
solution to a v ery sm all extent.
T he source rocks m ust p re d o m in a n tly have b een n o n -c al­
careous sedim ents. T he L ow er C am b rian fossils, u su ally wellp reserv ed a n d free o f ad h erin g ro c k particles m ost likely cam e
from the sam e u n co n so lid ated sands, w hich co n trib u ted to the
E xsulans lim estone.
P ro b ab ly d ue to an insufficient a m o u n t o f C alcium carbonate
cem en tatio n d id not tak e place. It h as b een suggested th a t c a r­
b o n ate cem en tatio n in sandstones m ay be b ase d on ca rb o n ate
in tro d u ced from w ithout, b u t in m ost cases the c a rb o n ate w ill be
the p ro d u c t o f the solution of shells a n d other calcareous m aterial
b u ried in th e san d . By slight m igration an d rep rec ip itatio n the
local cem ent is form ed. In the B ornholm region at the tim e of
the deposition of the K alby clay the only ca rb o n ate source a v a ila­
ble w as th e E xsulans lim estone, the u p p e r p a rt of w hich m ust have
b een developed as a siltstone corresponding to the sam ples from
the clay containing Jincella parva a n d Ctenocephalus exsulans.
T he tim e in terv al betw een deposition o f the E xsulans lim estone
a n d the K alby clay w as supposedly of short d u ra tio n , only
allow ing the erosion to rem ove the u p p er, non-calcareous p a rt of
the E xsulans sequence. T he conclusion m ust be th a t the su p p ly of
C alcium carbonate w as very lim ited, an d this possibly accounts for
the m issing lithification at the tim e o f or shortly after the sed im en ­
tation. T he re aso n w hy lithification h as not ta k e n place u p to the
presen t d ay is not know n.
D i s c u s s i o n : T he type locality of the E xsulans lim estone is
Kiviks E sp erö d in Scania. T he lim estone, even if not p ro p erly
n am ed according to m o d ern principles of stratig ra p h ic al classi-
10
Nr. 14
fication, ra n k s as a form ation. T he nam e is w ell-established in the
literatu re, a n d for this re aso n possibly sho uld not be rejected.
W ith reg ard to B ornholm the present w riter considered d i­
viding the E xsulans lim estone as a fo rm atio n into two m em b ers:
T he B o rreg ard lim estone m em b er (th e lim estone p ro p e r) an d the
K alby clay m em ber. T he two m em bers th en in m an y respects
w o u ld form a unit, a n d they are only sep a rated by a m in o r b re ak
in sed im en tation. O n the other h a n d the Exsulans lim estone is
w idely recognized as a un it belonging to the Triplagnostiis gibbus
zone. T hen, by establishing the K alby clay as a fo rm atio n the
E xsulans lim estone is m ain tain ed in the cu sto m ary sense.
O n the islan d of Ö land the E xsulans lim estone is overlain by
gray, m ore or less calcareous, th in -b ed d e d lim estone w ith interstratified lam in ae an d th in strata of shale. T his sequence, a l­
th o u g h n one of the index fossils from zone B 2 have b een found,
is co rrelated w ith th a t zone ( W e s t e r g a r d , 1946, p. 14). T he b asa l
p a rt of the sequence m ay be eq uivalent to the K alby clay. In
S cania the Tomagnostus fissus — Ptgchagnoslus atavus zone
seq uence consists solely of alum shale, as does the p a rt o f this zone
overlying the K alby clay.
Early Middle Cambrian history and paleogeography
After d eposition of the B ispebjerg san d sto n e at the tim e of the
L ow er C am b rian H olm ia torelli — Kjerulfia lundgreni zone (see
text-fig. 2) a regression set in, an d ph o sp h o rite im p reg n ated the
u p p e r p a rt of the sandstone. T he follow ing h iatus, a p a rt from a
m in o r tran sg ression, co rresponds to the rest of the L ow er C am ­
b ria n a n d the b a sa l p a rt o f the M iddle C am b rian . T he presence of
beds fro m the Eccaparadoxides oelandicus stage in the S outh
Baltic h as not b een ascertained. A th in sequence of shales an d
lim estones w ithout any distinctive fossils fo u n d at som e S canian
localities m ay a rb itra rily be re ferred to this stage or to the Paradoxides paradoxissim us stage.
As in d icated b y the non-trilobite m ateria l in the K alby clay
the B o rn h o lm a re a w as subm erged for a short w hile in the late
L ow er C am b rian . T he p resen t w riter has not yet finished his
studies of the non-trilobite fossils, b u t he believes th a t all of the
N r. 14
11
Fig. 2. The Lower and early Middle Cambrian sections at 01eaa and Lsesaa,
Bornholm.
12
Nr. 14
L ow er C am b rian species contained in the clay a n d in the E xsiilans
lim estone m ost likely originated from the Strenuella linnarssoni
zone. T he sea covering B ornholm at th at tim e w as supposedly
shallow , leaving a th in deposit o f san d poor in carb o n ates. T he
deposit w as not affected by lithification. T his a p p e a rs from the
b eau tifu lly p reserved fossils, free of ad h erin g sedim ent, fo u n d in
the K alby clay.
T he next tran sg ressio n o ccu rred at the tim e of the in itiatio n of
the Triplagnostiis gibbus zone. T he occurrence of n u m ero u s
specim ens of Acrothele (Redlichella) granúlala in the K alby clay
ind icates the fo rm e r presence o f a b ed sim ilar to the Acrothele
granúlala conglom erate, as clearly d em o n strated b y C. P o u l s e n
(1942). T he species is k n o w n from the Eccaparadoxides oelandicus
stage, b u t as all the L æ saa specim ens are strongly w o rn a n d rolled,
th ey m ost likely originated from a conglom erate like the b asa l
lay er o f the Triplagnostus gibbus zone ( B l ) . D uring this tra n s ­
gression p a rt o f the L ow er C am b rian unco n so lid ated deposits
w as rew o rk ed , a n d the resulting bed, of a lithology sim ilar to th a t
of the K alby clay, contained a m ixture o f M iddle C am b rian
b ra ch io p o d s an d L ow er C am b rian b ra ch io p o d s an d tu b u la r fossils.
A fter d eposition of the b asa l conglom erate the sea w ithdrew
for a sh o rt w hile. T he sea re tu rn e d , a n d the E xsulans lim estone
w as deposited. M aterial from the unco n so lid ated Acrothele gra­
núlala conglom erate including ro u n d e d q u artz grains a n d phosp h o ritic peb b les from the R ispebjerg sandstone w ere in co rp o rated .
Also prev io u sly u n d istu rb e d deposits from the Strenuella linnars­
soni zone w ere rew orked, a n d L ow er C am b rian fossils w ere em ­
b e d d e d in the lim estone.
T o w ard s the end o f the tim e of the Triplagnostus gibbus zone
the b a sin sh allow ed up, an d fine san d w as deposited. A regression
follow ed, a n d ph o sp h o rite im p reg n ated the san d y u p p e r p a r t of
the E xsulans lim estone. Possibly the sed im en tatio n co n tin u ed
p ra ctically u n in te rru p te d slightly across th e b o u n d a ry betw een
th e Triplagnostus gibbus zone a n d the Tomagnostus fissus —
P tychagnostus atavus zone. T his possibility is in d icated by the
sp ecim en of P tychagnostus atauus show ing th e sam e ph o sp h o ritic
state of p reserv atio n as the E xsulans siltstone trilobites fo u n d in
the clav.
13
N r. U
At early Tomagnostus fissus — Ptychagnostus ataviis zone tim e
the sea w ith d rew com pletely for a sh o rt w hile, an d the erosion
rem o v ed the san d y u p p e r p a rt of the E xsulans lim estone. Still at
the tim e of this zone the sea re tu rn ed , a n d the K alby clay w as
deposited p ro b a b ly over a n area of the sam e extent as th at of the
E xsulans lim estone. In the clay the elem ents o f the fo u r previous
tran sg ressio n s m ay be identified, as dem o n strated above. The
L ow er C am b rian fossils m ay be divided into a group of wellpreserv ed specim ens an d a group of b ad ly p reserv ed (w o rn )
specim ens. Som e o f the species are found in b oth groups. P ro b ab ly
all of the species originated from the Strem iella linnarssoni zone.
T he b ad ly p reserv ed group is su p p o sed to have b een redeposited
two o r th ree tim es, in the first place in the Acrothele granúlala
conglom erate, secondly in the E xsulans lim estone, a n d finally in
the K alby clay. T he w ell-preserved specim ens are su p p o sed to
hav e b een w ash ed out fro m original Strem iella linnarssoni zone
beds, u n d istu rb ed by the previous transgressions.
T he tran sg ressio n resp o n sib le for the deposition of the K alby
clay w as of sh o rt d u ratio n . Follow ing a sh o rt b re a k in the sed im en ­
tatio n the p y ritic conglom erate w as deposited on top of the K alby
clay. A n o th er h iatu s follow ed, a n d d u rin g this in te rru p tio n the
ero sio n rem o v ed the re m ain in g u n d istu rb e d p arts of the Strenuella
linnarssoni zone beds, th e rests, if any, of the Acrothele granúlala
conglom erate, a n d in m ost places the K alby clay an d the overlying
conglom erate.
W h e n th e su b seq u e n t transgression set in at the tim e of the
u p p er p a rt of th e Tom agnostus fissus — Ptychagnostus atavus zone
the en v iro n m en t h a d changed, a n d ab ru p tly , w ithout an y tran sitio n
beds, alu m shales w ere deposited. T his p h ase w as initiated at
th e close of zone B 2, as the b a sa l p a rt of the shale sequence at
01eaa contains the in dex fossil P tychagnostus atavus. The stable
conditions p ersisted th ro u g h o u t the H ypagnostus parvifrons zone
a n d the Ptychagnostus punctuosus zone of the Paradoxides paradoxissimus stage.
Geological Institute of the University of Copenhagen
References
K. a . 1902a: Bornholms Paradoxideslag og deres Fauna.
Danmarks Geol. Undersøgelse, ser. 2, no. 13.
— 1902b: Studier dfver Skandinaviens Paradoxideslag. Geol. Foren.
Stockholm Forhandl., vol. 24, no. 5.
H a n s e n , K. 1937: Sammenlignende Studier over Kambriet i Skåne og
på Bornholm. Medd. Dansk. Geol. Forening, vol. 9, no. 2.
P o u l s e n , C. 1942: Nogle hidtil ukendte Fossiler fra Bornholms Exsulanskalk. Medd. Dansk. Geol. Forening, vol. 10, no. 2.
W e s t e r g å r d , A. H. 1946: Agnostidea of the Middle Cambrian of
Sweden. Sveriges Geol. Undersdkning, ser. C, no. 477.
Gronw all,
Indleveret til Selskabet den 18. juni 1963.
Færdig fra trykkeriet den 8. november 1963.
Det Kongelige Danske Videnskabernes Selskab
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J ensen , P. B oysen : Untersuchungen über Determination und
Differenzierung. 2. Über die Wachstumsvorgänge in der Spitze
der W urzelhaare von Phleum. With an English Summary. 1954 3,50
B öving, Adam G.: Mature Larvae of the Beetle-Family Anobiidae. 1954........................................................................................ 35,00
Gamow, G.: Possible Mathematical Relation between Deoxyri­
bonucleic Acid and Proteins. 1954 .............................................. 2,00
B drgesen , F.: Some Marine Algae from Mauritius. Additions
to the Parts Previously Published. VI. 1954 ............................ 8,00
Jensen , P. B oysen : Untersuchungen über Determination und
Differenzierung. 3. Über die Wirkungsweise des determi­
nierenden Faktors, der bei der Bildung der W urzelhaare
von Lepidium, Sinapis und Phleum tätig ist. With an Eng­
lish Summary. 1955......................................................................... 4,50
S alomonsen, F in n : The Evolutionary Significance of BirdMigration. 1955.................................................................................. 6,00
7. Munch -P etersen , Agnete , Kalckar, H erman M., and S mith,
E velyn E. B.: Uridyl Transferases, their Occurrence and
Physiological Role. 1955 ................................................................
8. Gamow, G.: On Information Transfer from Nucleic Acids to
Proteins. 1955....................................................................................
9. H evesy , G.: Conservation of Skeletal Calcium Atoms through
Life. 1955...........................................................................................
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Notes. 1956
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Genus Erodium with Special References to the Collective
Species E. Cicutarium (L ) L’Her. 1958 ...................................... 4,00
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in dem Epikotyl von Phaseolus (Die Brückentheorie der
Wuchsstoffwirkung). With an English Summary. 1958 ....... 7,00
Golomb, S. W., W elch , L. R., and D elbrück , M.: Construction
and Properties of Comma-Free Codes. 1958............................ 5,00
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Differenzierung. 6. Über den Aufbau des Zellwandmusters des
Blattes von Helodea densa. With an English Summary. 1959 5,00
N ielsen , E rik T ete n s : On the Habits of the Migratory But­
terfly Ascia monusle L. 1961......................................................... 12,00
P oulsen , Valdemar : Notes on Hyolithellus Billings, 1871, Class
Pogonophora Johannson, 1937. 1963 .......................................... 2,50
P oulsen , Valdemar : Ctenopgge (Ctenopgge) pecten tenais n.
subsp. from the Upper Cambrian of Bornholm. 1963 ........... 2,00
P oulsen , Valdemar : The Lower Cambrian Kalby-Ler (Kalby
Clay) on the Island of Bornholm. 1963 ................................... . 3,00
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Id: 264
Forfatter: Poulsen, Valdemar
Titel: The Lower Cambrian Kalby-Ler (Kalby Clay) on the Island of Bornholm.
År: 1963
ISBN:
Serietitel: Biologiske Meddelelser
Serienr: B 23:14
SerienrFork: B
Sprogkode: Eng