IN THE ANGLO-PARIS BASIN 77 



5465), together with species of Hoplites (H.) of both the lyelli and spathi Subzones. 

 This dentatus Zone sequence in the central area of the Kent Coalfield thins consider- 

 ably in a south westerly direction towards the outcrop, and there is evidence to 

 suggest that it thins also eastwards towards the Kent coast. 



Ringwould 



The Mesozoic rocks traversed by the boring for the National Coal Board made in 

 1955 and situated 760 yds W. i4°S. of St. Nicholas's Church, Ringwould (TR 

 35294812), has been described by Bisson (in Bisson et al., 1967 ; 111-114), and fossils 

 from the Gault were identified by Casey. The Upper-Lower Gault junction consists 

 of a phosphatic nodule bed and was met at a depth of 839 feet 4 inches (255-83 m.). 

 The top of the tough phosphatic rock bed of the type seen elsewhere at the base of the 

 Gault was reached at a depth of 876 feet 11 inches (267-28 m.). The Lower Gault, 

 therefore, has thinned to 37 feet 3 inches (11-35 m -) an d the basal few inches in fact 

 may well be of mammillatum Zone age. A re-examination of the fragments of the 

 core preserved in the Institute of Geological Sciences has yielded the following 

 additional information. 



Crushed Dimorphopiites comparable to D. tethydis Spath non Bayle occur at depths 

 of 842 feet 3 inches (256-71 m.) and 845 feet 1 inch (257-58 m.) and indicate either the 

 top of the meandrinus Subzone, or the lautus Zone. At 860 feet 5 inches (262-25 m.), 

 a specimen of Hamites tenuicostatus together with a juvenile ? Dimorphopiites niobe 

 at 862 feet 2 inches (262-79 m.) suggest the presence of the niobe Subzone. The 

 intermedins Subzone is certainly represented at 866 feet 8 inches (264-16 m.) and 

 867 feet 9 inches (264-49 m.) by crushed examples of Anahoplites intermedins. The 

 presence of the spathi Subzone is indicated by crushed specimens of Hoplites (H.) at 

 871 feet 11 inches (265-76 m.) to 872 feet 1 inch (265-82 m.) in dark grey clay. At 

 873 feet (265*25 m.) the clays become glauconitic, and at 875 feet 10 inches (266-95 m.) 

 they become sandy for the remaining 1 foot 1 inch (0-33 m.) before the basal rock bed 

 is reached. 



The sequence in the lower part of the Middle Albian sediments is demonstrably 

 thinner than at Tilmanstone where ' dark sandy Gault ' commences some 21 feet 

 (6-4 m.) above the base. An even thinner sequence may be present in the next 

 boring mentioned here. 



St. Margaret's Bay. 



The National Coal Board boring at St. Margaret's Bay situated 1030 yds E. 30°N. 

 of St. Margaret's Church, St. Margaret's at Cliffe (TR 36654533), has been described 

 by Bisson and Melville (in Bisson et al., 1967 ; 105-110). The bulk of the sequence 

 was chipped, but at a depth of 800 feet (243-84 m.) cores were taken for 2 feet 

 (o-6i m.), at 830 feet (252-98 m.) a 1 foot (0-30 m.) core was taken, and a 3 feet 8 inch 

 (1-12 m.) core from 840 feet (256-03 m.) and the base of the Gault at 843 feet 8 inches 

 (257-15 m.). The only ammonite recorded was a specimen of a mortoniceratid 

 ammonite, probably Prohysteroceras, said to have come from a depth of 830 feet 

 (252-98 m.). What is probably a portion of the same ammonite is stated to have 

 come from a depth of 830 feet 3 inches (253-05 m.). Casey considers that its position 



