Kambr subholmiowy w północno-wschodniej Polsce

Abstract

SUB-HOLMIA CAMBRIAN DEPOSITS IN THE NORTH-EASTERN AREA OF POLANDSummarySo scarce evidences concerning the Cambrian deposits in the platform area of Poland have been responsible for wrong stratigraphical and palaeogeographical conceptions. At present, owing to a greater amount of appropriate material and its analysis, a revision of the previous interpretation seems to be necessary (Fig. 1). According to the encountered fauna characteristic of the Lower Cambrian, thedeposits so far referred to the Eocambrian (= Wendian) should be related with this subsystem.The fauna of the sub-Holmia Stage of the north-eastern area of Poland is presented in Tab. 1. As a basis for the detailed subdivision of this stage served here the non-trilobite skeletal fauna. In the platform deposits of the Lower Cambrian of the sub-Holmia stage two, already at present, faunistic horizons can be distinguished: the lower horizon with Sabellidites cambriensis and Platysolenites antiquissimus, and the upper horizon with Mobergella. These horizons have their equivalents in the lowermost Cambrian of Scand1navia, Baltic countries and West Ukraine.Among the fossils described in this paper (Tabs. I-V) are found representatives of Annelida and Incertae sedis, along with a new species Coleoella differo sp. nov.,the description of which is given below.Mollusca (= Incertae sedis F i s h e r 1962)FamiIy Coleoidae F i s h e r 1962Genus Coleolella M i s s a r z h e v s k y 1969Coleolella differo Sp. novoH o l o t y p e: Tabl. IV, Figs. 11, 12.S t r a t i g r a p h i e  p o s i t i o n: Lower Cambrian, horizon with Platysolenites antiquissimusO c c u r r e n c e  s i t e: East Poland, bore hole Tłuszcz IG-1, depth 2497,2 m. The individual is found by K. Lendzion in 1966.D i a g n o s i s: Elongated, cane-shaped test, cylindric in its aperture portion. Outer surface of test regularly ribbed. In the apical part - slightly bentM a t e r i a 1: One specimen.D i m e n s i o n s  i n  mm:length of test - 8,3width at the aperture part - 1,1width at the apical part - 0,2angle between walls - 3°D e s c r i p t i o n: Very small test in the shape of an elongated, narrow cone with a slightly bent apex. Towards the aperture the opening between the walls disappears, and the test takes a cylindrical shape. The outer surface of the test distinctly, regularly, transversally ribbed. The amount of ribs in 1 mm changes from the apex to the aperture. In the apical part there are 16 ribs in 1 mm, whereas in the aperture part - only 5. The ribs are narrow and sharp-edged. Furrows are slightly broader and almost flat. In the near-apical part the ribs are narrower and lower. For the most part the test is pyritized.