Southern Region Chalk Group Lithostratigraphy: The North Downs (Robinson, 1986) - Shakespeare Cliff Member

The Shakespeare Cliff Member (stratotype: Akers Steps [TR 297 394]), 26.5 m thick at Akers Steps, comprises beds of nodular chalk, hardgrounds and wispy marls (Robinson, 1986). In the North Downs, the lowest 10.8 m of the member have formerly been referred to as the 'Grit Bed' or Melbourn Rock Beds (Price, 1877; Hill, 1886; Robinson, 1986), but only the lowest part of the succession equates with the Melbourn Rock of the type area and as used by Mortimore (1986a) in southern England (Wood, 1996). The remainder of the Melbourn Rock Beds is coarsely bioclastic chalk, with abundant inoceramid bivalve shell debris, mostly of Mytiloides. The base of the member is the lithological contrast at the junction of the soft, marly Plenus Marls Formation and the hard, nodular, indurated chalk at the base of the Shakespeare Cliff Member (Robinson, 1986). The top is immediately below the base of Warren Marl 1, which marks the base of the overlying Aycliff Member (Robinson, 1986). In the upper part of the Shakespeare Cliff Member, the thick Round Down Marl is conspicuous in coastal sections, typically enclosing lenticles of white chalk and overlying intermittently spongiferous chalk (Robinson, 1986).

Macrofossil Biozonation: (M. geslinianum Zone (pars); Wood, 1993), N. juddii Zone, Mytiloides spp. Zone (sensu Wood, 1996) & T. lata Zone (pars).

Correlation: see Correlation with other lithostratigraphical schemes for the Southern Region

see Correlation with other UK regions

References

ROBINSON, N D.1986. Lithostratigraphy of the Chalk Group of the North Downs, southeast England. Proceedings of the Geologists' Association, Vol. 97, 141-170.

HILL, W. 1886. On the beds between the Upper and Lower Chalk of Dover, and their comparison with the Middle Chalk of Cambridgeshire. Quarterly Journal of the Geological Society of London, Vol. 42, 232-248.

MORTIMORE, R N.1986a. Stratigraphy of the Upper Cretaceous White Chalk of Sussex. Proceedings of the Geologists' Association, Vol. 97(2), 97-139.

PRICE, F G H. 1877. On the beds between the Gault and Upper Chalk near Folkestone. Quarterly Journal of the Geological Society of London, Vol. 33, 431-48.

WOOD, C. J. 1996. Upper Cretaceous: the Chalk Group. In SUMBLER, M. G., British Regional Geology: London and the Thames Valley. Fourth Edition. (London: HMSO for the British Geological Survey)

See: Melbourn Rock (Traditional Classification), Melbourn Rock (Mortimore, 1986a), hardground, marl, Plenus Marls Formation, Aycliff Member