Keyword "HARDGROUNDS" in:

New hardgrounds in the Upper Cretaceous sediments at Čenkov (central Bohemia)
Žítt,J., Nekovařík,Č., Svoboda,P., volume 36, 2003 (GRR for 2002), pages 50–51
pdf (0.95 MB)

Finds of borings from the Early Devonian of the Barrandian area
Mikuláš,R., volume 27, 1994 (GRR for 1993), pages 65–66
pdf (0.36 MB)