. Bulletin of the British Museum (Natural History), la géologie. Stoke Service Shilllngstone CÉNOMANIEN TURONIEN VW CO. 17-20 m omis ^ chalk Marly sable vert supérieur B 'O' Marl Glauconitiques lit Boulder w *sous-sol lit. Cenomonion - mi - non séquence w&gt ; ;^-i-ife'4i3 Fig. 15 La relation entre le milieu des non-Cénomanien séquence et les sous-sol de craie lit dans le centre de Dorset. L'ornement utilisé dans le benthonic graphiques ratio/planctoniques est expliqué dans la Fig. 12c. Oxycona Marssonella (Reuss) imitant M. ozawai dans les deux cycles précédant immédiatement la non-séquence. De retour au modèle (Fig. 13), ch

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. Bulletin of the British Museum (Natural History), Geology. Stoke Wake TURONIAN Vw CENOMANIAN Shilllngstone CO. 17-20 m omitted ^ Marly chalk Upper Greensand B 'Glauconitic Marl' O Boulder Bed w *Basement Bed. Mid - Cenomonion non - sequence w> ;^-i-ife'4i3 Fig. 15 The relationship between the mid-Cenomanian non-sequence and the Chalk Basement Bed in central Dorset. The ornament used in the planktonic/benthonic ratio graphs is explained in Fig. 12c. Marssonella oxycona (Reuss) mimicking M. ozawai in the two cycles immediately preceding the non-sequence. Returning to the model (Fig. 13), chalk deposition should continue above the non-sequence m the centre of the basin and, since the lithological changes would be slight, it could only be detected palaeontologically. However, on the margins of the basin a more dramatic sedimento- logical change would be expected. In these areas the calcareous sandstones (postulated in the model) would be replaced by Middle and Upper Cenomanian chalk, giving an easily recognizable horizon. It is not surprising that in Dorset the non-sequence becomes a feature of such importance that it dominates the whole of mid-Cretaceous stratigraphy in that area. The data concerning this level has been summarized by Kennedy (1970: fig. 19) although no real explanation of the feature was given in his account. In Dorset (Fig. 14) there is a transition from an 'invisible' non-sequence into the prominent Chalk Basement Bed - with its rich fauna of phosphatized macrofossils. To the east of Stoke Wake (ST 763067) the Lower Chalk succession (Fig. 15) is normal, with a bed of 'glauconitic marl' at its base. This marl - as was explained by Carter & Hart in the discussion of Kennedy (1969) -is not the same age as the 'Glauconitic Marl' of the Folkestone section. The most suitable sequence for direct comparison is that at Shilllngstone Lime Works (ST 824098) (Fig. 22, p. 77), where 42 m of chalk below the Plenus Marls has been recorded. A short distance

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