UTRECHT MICROPALEONTOLOGICAL BUllETINS

III,3. CORRELATION WITH LINDSTROM'S CONODONT-ZONATION OF THE LOWER ORDO-
VICIAN OF EUROPE
In fig. 19 Lindstrom's (1971) conodont-zonation of the Lower Ordovician
of Europe is tentatively correlated with the conodont-zonation presented in
this paper. A correlation of Lindstrom's zonation and Tjernvik's (1956)
trilobite- and graptolite-zonation (based on the data from Lindstrom (1971))
was already given in fig. 11.
The oldest conodont-zone mentioned by Lindstrom (1971) is the Cordylodus
angulatus Zone, which he correlated with the British Zone of Diet yonema
flabelliforme and with the Estonian Pakerortian Stage. As Lindstrom
gave no exact faunal composition of his Cordylodus angulatus Zone, its
correlation is difficult to make. If, however, Cordylodus angulatus is considered
characteristic for Lindstrom's oldest zone and Paltodus deltifer (=
Drepanoistodus inaequalis emend. herein) is considered typical for
Lindstrom's next following Zone of Paltodus deltifer (fig. 19), the Cordylodus
angulatus Zone must be correlative with our Cordylodus angulatus/
C.prion Assemblage Zone (figs. 15 and 19). If so, the Cordylodus angulatus
Zone is correlative with at least part of the British Zone of Dictyonema
flabelliforme (fig. 19).
The Paltodus deltifer Zone of Lindstrom (1971) seems to be characterized
by the occurrence of Paltodus deltifer (= Drepanoistodus inaequalis emend.
herein), together with the genus Cordylodus, Oneotodus variabilis (= elements
of Drepanoistodus acuminatus emend. herein) and Paroistodus numarcuatus
(= elements of Drepanoistodus numarcuatus emend. herein plus elements of
Paroistodus amoenus emend. herein). If Paltodus deltifer is considered
characteristic for this zone and Paroistodus proteus (= elements of Paroistodus
parallelus emend. herein) is typical for Lindstrom's next younger zone
(fig. 19), then the Paltodus deltifer Zone must correspond to a rock-interval
containing the Cordylodus rotundatus Zone, up to and including the Prioniodus
deltatus Zone of north-western bland (figs. 15 and 19). It would imply,
that at least part of Lindstrom's Paltodus deltifer Zone corresponds to the
British Zone of Bryograptus (fig. 19).
Lindstrom's Zone of Paroistodus proteus would contain Paroistodus
proteus (= elements of our Paroistodus parallelus) and Paltodus inconstans (=
elements of our Drepanoistodus inconstans) as "leading species". Because of
the range of the latter species (fig. 15), this zone would be correlative with
the rock-interval on north-western bland, containing the Drepanoistodus
inconstans Zone and the Triangulodus subtilis/Gothodus microdentatus
Zone (fig. 19). This would imply, that Lindstrom's Zone of Paroistodus
proteus corresponds to Tjernvik's Zone of Plesiomegalaspis armata on N.W.