Chalk Group Lithostratigraphy: Northern England - Sewerby Member

The Sewerby Member (stratotype: Danes Dyke - Sewerby Steps [######## to TA 202 687]), c. 72 m thick and representing the youngest and thickest part of the Flamborough Formation, is characterised by the upward development of thin-bedded, stylolitic chalk, although massive-bedded, relatively harder chalks locally occur higher in the succession (Whitham, 1993). About 63 marls are recognised in the succession, at a higher frequency than seen in the underlying members, the base of the Danes Dyke Member being marked by the Danes Dyke Marl (Whitham, 1993). The top of the Sewerby Member, and of the Flamborough Chalk, is undefined, presumably because of the probable upward continuation of this interval into younger unexposed chalk at some inland localities (Whitham, 1993). Within the Sewerby Member there are conspicuous sponge-rich intervals (The Flamborough Sponge Beds), and acmes of crinoids, echinoids and oysters; ammonites are rare, except near the top where scaphitids are common (Whitham, 1993).

Macrofossil Biozonation: M. testudinarius Zone (pars), U. anglicus Zone & I. lingua Zone

Correlation: see Correlation with other UK Chalk Group successions

References

WHITHAM, F.1993. The stratigraphy of the Upper Cretaceous Flamborough Chalk Formation north of the Humber, north-east England. Proceedings of the Yorkshire Geological Society, Vol. 49(3), 235-258.