Letná Formation
The Letná Formation is a Late Ordovician (Sandbian, or in the regional stratigraphy Berounian) geologic formation of the Prague Basin, Bohemian Massif in the Czech Republic. The formation crops out in the Czech capital, more specifically at Letná Hill, after which the formation is named. The type locality is located at Malá Strana, Holešovice district.

The more than thick formation comprises a rhythmic alternation of sandstones (greywackes and subgreywackes), quartzites, intercalated with siltstones and shales deposited in marine flysch-like environments.

Because of the excellent preservation, including gut remains, of a wide assemblage of early Paleozoic taxa in which trilobites dominate, the formation, which is lean in fossils in many areas but exceptionally rich in what has been interpreted as storm beds, has been designated a "Konservat-Lagerstätte".
Q62100
Late Ordovician
LOC
Q1807140
Sandbian
TIME
None
Berounian
UNK
None
Prague Basin
UNK
Q704453
Bohemian Massif
LOC
Q531953
crops out
Concept
Q1973416
type locality
Concept
Q13085
sandstone
Concept
Q917545
greywacke
Concept
None
subgreywacke
UNK
Q237883
quartzite
Concept
Q565731
siltstone
Concept
Q751300
shale
Concept
Q756914
flysch
Concept
Q1994702
environments
UNK
Q17170
trilobite
Concept
Q2122699
Konservat-Lagerstätte
LOC
Q96096125
Letná Formation
LOC
subclass of