Geology December 2003 Vol 52/4 []

CONTENTS & ABSTRACTS

InEnglish. Summaries in Estonian

Proceedings of the Estonian Academy of Sciences.

Geology



Volume 52 No. 4December 2003



DimitriKaljo 75; 197–198

AlvarSoesoo, 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. (typespecies selected here is Grewingkia bilateralis Neuman, 1969) is erectedfor streptelasmatid rugose corals with Grewingkia-like ontogeny lackinga cardinal fossula sensu stricto. In addition, the new genus Fosselasma gen. nov.(type species selected here is Streptelasma unicum Neuman, 1975) iserected for species with a Streptelasma-like ontogeny but provided with a cardinal septofossula. Species of Eurogrewingkiaare currently recognized from the Upper Ordovician, Rawtheyan–Hirnantianstrata in Europe and North America. Species of Fosselasma are found onlyin 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 Ctenognathodusform an important part of the fossil fauna through the Wenlock–Ludlow boundarybeds on Saaremaa Island. In the collections from the Anikaitse, Hülge, andSoeginina cliffs of the uppermost Rootsiküla and lowermost Paadla stages threenew species of Ctenognathodus areidentified, 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. Conodontevidence suggests that the Soeginina Beds in the stratotype section are the lowest stratigraphic unit of the Paadla Stageand the Ludlow Series, as presumed earlier by cyclostratigraphicinvestigations. The layers of the Anikaitse cliff with unique conodont faunaare 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 thesquamations of Phlebolepis elegansPander 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, andthe distribution of facies during Himmiste time it is concluded that thethelodonts died in a shallow depression on the bottom of the lagoon behind thereef belt towards the land; the depression acted as a trap during low tide. Unfavourable conditions, primarily the lackof oxygen in warm and shallow water, caused the perishing of the Phlebolepis shoal. Very low waveactivity prevented post-mortem disintegrationof the squamation and rapid conservation in mud saved the exoskeletons from scattering.

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

Contents ofvolume 52; 266–267