View source for Southern Region Chalk Group Lithostratigraphy: The North Downs (Robinson, 1986) - St Margarets Member



The St. Margarets Member (stratotype: Langdon Stairs [TR 345 425]), 38.3 m thick at Langdon Stairs, comprises hard, nodular, flinty chalk with mineralised hardgrounds and marl seams throughout (Robinson, 1986). The base is marked by the base of the Crab Bay Marl, and the top is indicated by East Cliff Marl 2, or, in condensed sections, the top of the Rochester Hardground (Robinson, 1986). The member contains a number of key named lithostratigraphical markers, including (in ascending order): the Crab Bay Marl, the Fan Bay Marls, the Bantam Hole Hardgrounds, the Cobbler Marl, the Lighthouse Down Hardgrounds, the South Foreland Hardgrounds, the Ness Point Marls, the Parlour Hardground, the Pines Garden Hardground, the Medway Marls, the Strood Flint, the Bay Hill Hardground, the Edinburgh Hill Inoceramid Band, the Corn Hill Hardgrounds, the Rochester Hardground and the East Cliff Marls (Robinson, 1986).

'''Macrofossil Biozonation''':             ''T. lata'' Zone (pars), ''S. plana'' Zone & ''M. cortestudinarium'' Zone (Robinson, 1986; Bristow ''et al''., 1997)

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

see Correlation with other UK regions

===References===

'''BRISTOW, C. R., MORTIMORE, R. N. & WOOD, C. J.''' 1997. Lithostratigraphy for mapping the Chalk of southern England.'' Proceedings of the Geologists' Association'', Vol. '''108''', 293-315.

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

See:                      hardground, flint, marl (plus key markers highlighted above)

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