and four left in open nomenclature. Among the six positively identified
acritarch species, three have both dubious chronostratigraphic significance and non-distinct morphology (e.g.,
Veryhachium triangulatum, Veryhachium minutum, and
Leiosphaeridia ketchenata), and the other three
(Diexallophasis denticulata[=Evittia remota], Multiplicisphaeridium raspa, andTylotopalla caelamenicutis)
cross the Ordovician–Silurian boundary in the Bohemian sections, and are also known to occur commonly in
Silurian strata in other localities.