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The lower boundary is defined by the sharp contact between underlying calcareous sandstones of the Langøyene Sandstone Formation (Brenchley & Newall 1975, equivalent to 5b of Kiær 1897, 1902) and the dark grey silty shales with minor siltstones of the Solvik Formation. A 60 cm‑thick nodular limestone occurs locally as a basal development of the overlying unit (Fig. 7a). The base of the lowermost Myren Member is, by definition, coincident with the base of the Solvik Formation. The Myren Member is approximately 160 m thick and includes 6a and 6b of Kiær (1908) in the type area of the Solvik Formation. The name of the member is derived from a locality on the east coast of Malmøya (NM988380) which shows the most complete development of the lower parts of this unit. Detailed correlations of several partial sections both here and on the west coast of the island suggest a minimum thickness of 120 m for Kiær's 6a (in contrast to his suggested thickness of 50 to 60 m) and a total minimum thickness of approximately 160 m for the whole Myren Member. The member consists of shales with minor laminae and very thin interbeds of siltstone. Siltstones are most common in 6a‑alfa and 6b‑beta where they comprise 30% of the succession (Fig. 6). Body fossils are generally rare in the lower parts of the member, but in situ brachiopod associations dominated by Leangella scissa and Protatrypa malmoeyensis characterize 6b‑alfa and 6b‑beta respectively (Worsley 1971).