Stein Member
(Steinsleddet)
(Skjeseth 1963)
(Previously termed: 3c, Orthoceras Limestone, Steinkalksten).
Main Lithology. Limestone.
Basal Stratotype. Mjøsa (Ringsaker): Stein Farm on Steinsodden (NN 919 539).
Thickness. Mjøsa (Ringsaker): north of Redalen (ca. 40m).
Definition. Skjeseth (1963 p.71, Fig. 26) noted the occurrence of the bedded limestones and thin sandy shales and mudstones in several localities around Stein. The base of the Stein Member is taken at the first of the continuous limestone horizons. These contrast with the nodular limestones of the underlying Herram Member. A. Bjørlykke (1979) noted that the Stein Member is about 40m thick at Stein but as little as 5m thick in some other locations.
Fauna and Age. Kohut (1972 p.435) recorded conodont samples from the Stein Member at Raufoss (Toten), Herram and Steinsodden (both Ringsaker). He concluded (1972 pp.439-443) that the unit encompasses the zones of Paroistodus originalis and Microzarkodina parva and at least part of the Eoplacognathus variabilis Zone. More recent work by Rasmussen & Stouge (1988) indicates that the upper part of the member extends into the lower Eoplacognathus suecicus Zone.
(From Owen et al., 1990: The Ordovician Successions of the Oslo Region, Norway. NGU Special Publication 4. Figs. refer to the printed version.