UTRECHT MICROPALEONTOLOGICAL BUllETINS

Type-locality: Kopingsklint, section 1.
Type-strata: The basal portion of member Dk 1 .
Remarks: This conodont assemblage zone was based on two samples (3 and
4) of section 1 (chart II). Coelocerodontus bicostatus was not actually found
in this zone, but it might form part of the assemblage to judge from its
regional range (fig. 15).
II.2.4.4. The Drepanoistodus numarcuatus/Paroistodus amoenus Assemblage
Zone
Diagnosis: A conodont assemblage zone characterized by the occurrence of
Drepanoistodus numarcuatus and Paroistodus amoenus before the first
appearance of Drepanodus arcuatus (charts II and IV, fig. 15).
Description: In the rock-sequence of N.W. bland, Drepanoistodus numarcuatus
and Paroistodus amoenus start their range together. They were found
with Cordylodus angulatus, C.rotundatus, Drepanoistodus inaequalis and
D.acuminatus in all assemblages of this zone. Cordylodus prion and Coelocerodontus
variabilis were discontinuously encountered in this zone in section
14. At Kopingsklint Coelocerodontus bicostatus and c. variabilis were
not found in this zone; these species seem to end their ranges in this zone,
together with Cordy lodus prion (fig. 15).
Type-locality: Horns Udde, section 14, locality 1, see fig. 5.
Type-strata: Member Dh 1 and member Dkl of section 14 (chart IV).
Remarks: This zone was based on two rich faunas of section 14 and one
poor fauna in section 1. In contrast with section 14, Scolopodus peselephantis
and the coelocerodonts were not encountered in the fauna of section 1,
but these small conodonts may have escaped the author's attention during
the examination of the residue, which was rich in terrigenous clastics.
In section 14 the lower boundary of this zone coincides with the disconformity
at the top of member D,,_d 2, as a sample taken from the latter only
contained a few fragments of westergaardodinas and coelocerodonts, most
probably reworked and of Cambrian age.
11.2.4.5. The Drepanodus arcuatus Assemblage Zone
Diagnosis: A conodont assemblage zone defined by the occurrence of Drepanodus
arcuatus before the first appearance of Prioniodus deltatus (charts
II and IV, fig. 15).
Description: In rock-section 1 and in the small rock-section oflocality 2 near
Horns Udde (see fig. 5 and chart IV the inset) Drepanodus arcuatus was
found together with Drepanoistodus inaequalis, D. numarcuatus, Paroistodus