According to Jakub Prokop (personal communication 2001 in Z. Kvaček, Teodoridis in Sborn. Nár. Mus. Praze, Řada B, Přír. Vědy, 67(3-4): 86. Nov 2011) Equisetum bilinicum UNGER (1847, p. 124, pl. 37, figs 8-9, syn. Equisetites bilinicus (UNGER) UNGER 1850, p. 60) from the Early Miocene plastic clay of Břešťany (Priesen) is based on remains of insects (larval cases of Trichoptera), which commonly occur in the corresponding strata of the Bílina Mine.