UTRECHT MICROPALEONTOLOGICAL BUllETINS

Great Britain Sweden
Systems
Zone of Didymograptus
hirwulo
Subzone of Isograptus
gibberuZus
Zone of IsograptuB
gibberuZ.us
Subzone of
Didymograptus ni tidus
Zone of Phyllograp-tus
Zone of
angus1;ifolius eZongatus PZesiomegaZaspis estonica
Zone of
Zone of PhyUograptuB densus
Zone of Megalaspides dalecarZicus
Sub-
2) Graptol itie zones Tri lobi te-zona ti on
Series Graptolitic zones
systems Tjernvik (1956) N.W. Oland Tjernvlk (1956) .
Ordovician
Lower Didymograptus I
Ordo- Arenig - - --- - - --
vician
extensus
Subzone of
Didymograptus deflexu.s
Upper Subzone of
Tet;ragraptus
Zone of Didymograp-tus
baUicus
Zone of
Plesiomegalaspis
-------~-----
plani l imbata
Zone of Tetragraptu8
phy Z l-ograptoides
Zone of Dichograptus Undescribed dichograptids
Zone of
Plesiomegalaspis
armata
-?- -?
? ?
Zone of
Apatokephalus serratus
Zone of Clonograptus heres Zone of Shwnardia
Cambrian
Zone of Dictyonema fZabelli-1 )
Upper
Zone of Bryograptus
forme norvegicwn and
Tremadoc
Cambrian Bryograptus kjerulfi
Zone of Adelograptus
hunnebergensis
Zone of Dictyonema
flabeUiforme
Zone of Dictyonema
f~abeUit'orme
Zone of Dictyonema
sociale
1)The biozonation of the"Dictyonema shale" according to Hede (1951).
A correlation of some Upper Cambrian and Lower Ordovician biostratigraphic units from
Great Britain and from the Baltic area; with a comparison between the chronostratigraphic
units they originate from.