CONTENTS & ABSTRACTS

In English. Summaries in Estonian

Proceedings of the Estonian Academy of Sciences.

Geology

Volume 52 No. 4 December 2003

Dimitri Kaljo 75; 197–198

Alvar Soesoo, Anto Raukas, and Heldur Nestor

The new early Palaeozoic rugose coral genera Eurogrewingkia gen. nov. and Fosselasma gen. nov.; 199–212

Björn E. E. Neuman

Abstract. The new genus Eurogrewingkia gen. nov. (type species selected here is Grewingkia bilateralis Neuman, 1969) is erected for streptelasmatid rugose corals with Grewingkia-like ontogeny lacking a cardinal fossula sensu stricto. In addition, the new genus Fosselasma gen. nov. (type species selected here is Streptelasma unicum Neuman, 1975) is erected for species with a Streptelasma-like ontogeny but provided with a cardinal septofossula. Species of Eurogrewingkia are currently recognized from the Upper Ordovician, Rawtheyan–Hirnantian strata in Europe and North America. Species of Fosselasma are found only in Hirnantian strata in Sweden and Norway.

Key words: taxonomy, rugose corals, Upper Ordovician, Rawthyean, Hirnantian.

Wenlock–Ludlow boundary beds and conodonts of Saaremaa Island, Estonia; 213–238

Viive Viira and Rein Einasto

Abstract. Conodonts of the genus Ctenognathodus form an important part of the fossil fauna through the Wenlock–Ludlow boundary beds on Saaremaa Island. In the collections from the Anikaitse, Hülge, and Soeginina cliffs of the uppermost Rootsiküla and lowermost Paadla stages three new species of Ctenognathodus are identified, together with two new species of Ozarkodina. One more new species, Ctenognathodus jeppssoni sp. nov., is described from the Sauvere Beds of the Paadla Stage. Conodont evidence suggests that the Soeginina Beds in the stratotype section are the lowest stratigraphic unit of the Paadla Stage and the Ludlow Series, as presumed earlier by cyclostratigraphic investigations. The layers of the Anikaitse cliff with unique conodont fauna are considered as an independent rock-unit – the Anikaitse Beds.

Key words: conodonts, taxonomy, biostratigraphy, cyclicity, Wenlock, Ludlow, Estonia.

Sedimentation of the Himmiste-Kuigu fish bed (Ludlow of Estonia) and taphonomy of the Phlebolepis elegans Pander (Thelodonti) shoal; 239–265

Tiiu Märss, Helle Perens, and Tiiu Klaos

Abstract. Sediments with the squamations of Phlebolepis elegans Pander at Himmiste-Kuigu were formed in a lagoon of the Palaeobaltic Sea, situated in the tropical realm during Himmiste time of the Paadla Age, Ludlow, late Silurian. From the micro- and macrolithological features of the rocks, and the distribution of facies during Himmiste time it is concluded that the thelodonts died in a shallow depression on the bottom of the lagoon behind the reef belt towards the land; the depression acted as a trap during low tide. Unfavourable conditions, primarily the lack of oxygen in warm and shallow water, caused the perishing of the Phlebolepis shoal. Very low wave activity prevented post-mortem disintegration of the squamation and rapid conservation in mud saved the exoskeletons from scattering.

Key words: Thelodonti (Agnatha), taphonomy, Estonia, Ludlow, Silurian.

Contents of volume 52; 266–267