Fossil graptolites from Ordovician
These graptolites are from the Ordovician transition deposits are exposed in the Bardo Syncline in the southern Holy Cross Mountains (Kielce region, Poland). This is a small tectonic unit about 16 km long and 2–3 km wide, elongated NW–SE. This Variscan structure is composed of Ordovician and Silurian strata, truncated and overlain paraconformably by Devonian rocks. The Palaeozoic rocks are largely blanketed by a thick cover of Quaternary deposits. The outline of the Syncline is marked by diabases, which follow the boundary between different Silurian deposits: graptolitic shales and greywackes.