MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 27 



This uppermost division is represented at Sheppey by a continuation of the fourth 

 division whose stiff clays with septaria come in 300-350 feet above the base. It is 

 probable that most of the London Clay exposed at Sheppey falls within this (the 

 fourth) division, the only possible exception being the " Foreshore Beds "of Davis 

 (1936) which may mark the top of the third division. The first, second and most of 

 the third divisions of Wrigley (1924) lying below the surface at Sheppey, only 

 outcrop further east at Heme Bay and Reculver Bay, and are at present being 

 investigated by Mr. A. Hussain in the Department of Geology at Sheffield University. 



Davis recognized the following sequences in the Sheppey cliff section : 



(d) Stiff brown clays with few fossils . . . . .50' 



(c) Stiff grey and brown clays with good fauna and flora in 



lower part. Rarely in situ. . . . . .60' 



(b) Stiff blue clays. Few fossils. . . . . .50' 



(a) Foreshore. Barren clays, blue or lead coloured. 



Group (a) The " Foreshore Beds ", probably include the upper parts of Wrigley 's 

 third division, whilst beds (b), (c) and (d) seem to belong to his fourth division, (d) 

 including the Sheppey equivalent of Wrigley's division five. Samples have only been 

 collected from groups (a), (c) and (d) because group (b) was never clearly exposed 

 (Text-fig. 7). 



