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152 ADVANCES IN PALAEOICHTHYOLOGY Fig.2. A, Wood Bay Formation biostratigraphical scale. It presents the distribution of the Pteraspidiformes in the Woodfjord region. B, Wood Bay Formation lithological scale. The distribution of the Pteraspidiformes into the Austfjord-Dicksonfjord region is shown. sp. 2 which presents some Doryaspis nathorsti affinities. Daniel Goujet has identified Heintzosteus sp., and Gigantaspis isachseni and Arctolepis sp. are identified in the samples from the BG locality. The BC site contains Gigantaspis sp. and the same Doryaspis sp. 2 as in H 1-3 . These three localities are considered to be members of the Kapp Kjeldsen division due to the occurrence of Gigantaspis isachseni. The presence of Doryaspis sp. 2 and of the identified placoderms suggests a very high position in the division, close to the top, because of the similarity between Doryaspis sp. 2 and Doryaspis nathorsti (present only in the upper division). It is the same for the placoderm Arctolepis, a genus which presents its acme in the upper Keltiefjellet faunal division.
V. Pernegre, V. Dupret. Biostratigraphic correlations within Wood Bay Formation 153 The fauna of the BE locality is composed of Doryaspis sp. 1 and Doryaspis sp. 2 for the pteraspidiforms and Arctolepis decipiens and Arctaspis maxima as representatives of placoderms. In the C4 site we recognise the same pteraspidiforms as in the BE, associated with Arctolepis decipiens and an osteostracans, Meteoraspis lanternaria. The faunal list of the BD samples comprises Doryaspis sp. 1, Doryaspis sp. 2, Arctaspis maxima and Arctolepis sp. Those three field localities belong to the Keltiefjellet basal layers due to the occurrence of Arctolepis decipiens, Arctaspis maxima and Doryaspis sp. 1. So, these localities follow stratigraphically the preceding Kapp Kjeldsen ones (H 1- , BG, BC). 3 In conclusion, the new huge Doryaspis species can be used as a guide fossil for the transitional beds of the Kapp Kjeldsen - Keltiefjellet boundary (Fig. 2). The characteristic Keltiefjellet pteraspidiform fauna is identified in the samples from the A 16 and BH localities (Fig. 1). The occurrence of Doryaspis nathorsti in all this material suggests this interpretation. We establish the presence of Arctaspis sp. in both localities and of Arctolepis decipiens in the BH site, thus confirming the Keltiefjellet age. Two osteostracans have been identified in the material from the A 16 locality, Meteoraspis oblongata and Meteoraspis sp. The presence of Doryaspis nathorsti associated with Arctolepis decipiens is sufficient to characterise the Keltiefjellet faunal division (Fig. 2). Dicksonfjord and Austfjord area (Austfjorden and Dicksonfjorden Members) and comparison with the Woodfjord localities and fauna Other Spitsbergen material is available in the paleontological collections of the Muséum National d’Histoire Naturelle, Paris. Part of it was collected in 1964 by J. P. Lehman at Grønhorgdalen and another part was collected in the Dicksonfjord-Austfjord area during the 1969 French expedition (Fig. 1). Friend (1961) defines in this region two stratigraphic units based on their lithologic facies. The Austfjord Sandstone is composed of green-grey sandstones and conglomerates with intraclasts (Friend 1961). It is presented as the basal unit. The overlying unit named the Dicksonfjord Sandstone is similar lithologically to the upper northern divisions (red siltstones and sandstones). These units were revised by Friend et al. (1966) who renamed them as members. They considered the Austfjord Member as a lateral equivalent of the Kapp Kjeldsen faunal division and the Dicksonfjord Member as strictly similar to the Keltiefjellet and Stjørdalen divisions. This interpretation is only based on lithological conclusions without any faunal considerations. We know three localities from the Austfjord Member: B∆, B∆’, and BS (Fig. 1). We find in our samples from B∆ and B∆’ the pteraspidiforms Doryaspis sp. nov. and Gigantaspis laticephala, in association with the well preserved placoderms Dicksonosteus arcticus, Heintzosteus brevis, and Lehmanosteus hyperboreus (Goujet 1984). The same Doryaspis species with Nectaspis areolata and Hildenaspis digitalis is present in the BS samples. The fauna identified in this member (Fig. 2) is easily correlateable with the equivalent one of the Sigurdfjellet - Kapp Kjeldsen divisions (mainly the association Doryaspis – Gigantaspis with the occurrence of Heintzosteus for Kapp Kjeldsen). This faunal correlation confirms the Friend et al. (1966) geological
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LATVIJAS UNIVERSITĀTES RAKSTI 679.
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LATVIJAS UNIVERSITĀTES RAKSTI 679.
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Contents Ervīns Lukševičs and Ģ
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ACTA UNIVERSITATIS LATVIENSIS, 2004
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Ervīns Lukševičs, Ģirts Stinkul
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Olga Afanassieva. Microrelief on th
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C.G.Miller, T. Marss, H. Blom. New
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H.-P. Schultze, T. Marss. Revisitin
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O.A. Lebedev. A new tetrapod from R
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Page 159 and 160: Ž. Žigaite. New telodont from Tuv
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