Sundvollen Formation
The Sundvollen Formation is a geologic formation cropping out along the northern and eastern shores of Steinsfjorden, Oslo Region, Norway. It preserves fossils dating back to the Gorstian to Ludfordian stages of the Late Silurian period.
Description
The formation belongs to the Ringerike Group, overlies the Steinsfjorden Formation and is overlain by the Stubdal Formation. The fish assemblage originates from a horizon with fine-grained, dark greyish-green sandstone from the lowermost part of the formation.The formation comprises dark-grey siltstones associated with red sandstones and siltstones, with ripple marks, cross-laminations, and crack diapirs, and pseudo-nodules, carbonate concretions. The sequence is fining upwards in cyclothems. Tracks attributed to eurypterids have been found in the red siltstone. Turner. Boucot and Janis interpreted the environment to be possibly brackish-estuarine.
Fossil content
The following fossils have been reported from the formation:Fish
Ateleaspis sp.Loganellia cf. aldridgeiParalogania martinssoniPhlebolepis elegansPterygolepis cf. nitidaRhyncholepis parvulaThelodus laevisTyriaspis cf. whiteiEurypterids
Brachyopterella pentagonalisEurypterus tetragonophthalmusKiaeropterus ruedemanniMixopterus kiaeriNanahughmilleria norvegicaPterygotus (Erettopterus)Erettopterus holmiStylonuroides dolichopteroidesMixopterus sp.Nanahughmilleria sp.- ''Pterygotus sp.''
Invertebrates
;Crustaceans;ChasmataspididsKiaeria limuloides
;Xiphosura
Flora
- Plantae indet.Dictyocaris slimoni.