The oldest rocks of the Holy Cross Mountains, Poland - biostratigraphy of the Cambrian Czarna Shale Formation in the vicinity of Kotuszow

Three lower Cambrian acritarch assemblages recognized in four outcrops in the vicinity of Kotuszow in the southernmost part of the Palaeozoic inlier of the Holy Cross Mountains span a stratigraphic interval from the uppermost part of the Asteridium torncaum-Comasphaeridiunz velvetum Assemblage Zone to the Skiagia ornuta-Fimbriaglomerella membranacea Assemblage Zone (most probably its lower part). According to current views (Moczydlowska and Yin 2012), this interval corresponds to the upper part of the Fortunian and to Stage 2 of the Terreneuvian Series. The strata yielding the oldest assemblage are thus the oldest precisely documented rocks in the Palaeozoic succession of the Holy Cross Mountains, and the oldest Cambrian rocks exposed on the surface in Poland. The current biostratigraphic scheme for the pre-trilobitic part of the Cambrian System in the Holy Cross Mountains should be modified so that it is based on local acritarch interval subzones.