20 



MIDDLE ALBIAN STRATIGRAPHY 



Whether the daviesi Subzone is represented at this height is uncertain. Sediments 

 of daviesi Subzone age are 4 inches (o-ioi m.) thick in the Maidstone By-Pass. 



The nodule bed Division 6 is of cristatum Subzone age, and it is interesting to note 

 that there is a tendency for this bed to divide a little into two, a feature seen in 

 Division D in Sections 2 and 4 of the Maidstone By-Pass (Owen i960 ; 371). There 

 is no question of there being two distinct nodule beds, but the feature is of interest in 

 connection with the tectonic disturbance and associated erosion of the upper surface 

 of the Lower Gault in cristatum Subzone times (p. 72). 



Div. 

 6 



Li thology 



Brownish phosphatic nodules tending to divide Into two concentrations 

 oil In shelly medium-gray burrowed cloy. 



(vlii) Mid-grey shelly clay with fawn patches- some extensively 



burrowed; scattered phosphatic nodules and part phosphatlsed 

 fossils at base. 



(vii) Highly burrowed light fawn-grey clay, shelly and with lenticles 

 of marlstone at the base. 



vi) Mid-grey burrowed shelly clay 



n 



w 



Scam of scattered phosphatic nodulci~ 



(iv) Shelly mid- g rey clay. 



(Ill) Buffish phosphatic nodules in mid-grey clay. 



(li) Shelly mid grey clay with lighter patches. 



(i) Brown phosphatic nodules, mainly casts of fossils in shelly clay>^/|i 



Lightish fawn grey clay, shelly, becoming darker below and burrowed 



Ft Ins M. 



4-9 



1 



2-5 

 2 



7 

 1 



e 



1 



1- 



o-J 



Fig. 7. Section in Lower Gault at southern side of the Associated Portland Cement 

 Manufacturers' Holborough clay pit, 880 yds SE. of Paddlesworth, Snodland, Kent 

 (TQ 69156165). 



(b) Trottiscliffe 



The sequence exposed in the Rugby Portland Cement Co's Ford Place Clay pit 

 extends from the middle of the Folkestone Beds up to the varicosum Subzone of the 

 Upper Gault. The Middle Albian sediments are shown graphically in text-fig. 8. 

 Casey (1959) has given a brief account of the whole section, and a detailed account of 

 the Gault-Lower Greensand junction beds (1961a ; 545). The upper part of the 

 junction beds and the Gault have been described by Milbourne (1963) but his account 

 is inaccurate both in lithological detail and in its subzonal classification. The writer 

 has described the sequence in the spathi Subzone (1963a ; 38), but in view of Mil- 

 bourne's account of this section it is necessary to redescribe the sequence in the 

 Lower Gault (text-fig. 8) . 



Bed 9 of Casey (1961a ; 545) was stated to have a thickness of 3 feet (0-914 m.) and 

 by Milbourne (1963 ; 58) as 5 feet (1-524 m.) : it is capable of subdivision (text-fig. 8). 

 Bed 9 (ii) has yielded pyritic Hoplites (H.) spp. and Beudanticeras sp. and I follow 

 Milbourne in classifying this horizon with the lyelli Subzone. Whether the eodentatus 



