78 MIDDLE ALBIAN STRATIGRAPHY 



only 13 feet 8 inches (4-16 m.) above the base of the Gault is anomalous and should 

 not be accepted. However, the portion from 830 feet 3 inches (253-05 m.) is not 

 apparently derived and even if the specimen had come from the core between 800-802 

 feet (243-84 m.) this still suggests a thinner Lower Gault sequence than at Ringwould. 

 These records need to be verified in any future boring in this area, but the possibility 

 of early Upper Albian faulting here of the type seen in the region of the Thames E. of 

 London should not be excluded (Owen in press). The Gault as a whole on the 

 E. coast of Kent thins considerably northwards. In the Segas Deal Gas Works boring 

 (TR 374533) it is 86 feet (26-21 m.) thick and in the Thanet Water Board Well, 

 Margate (TR 365701), it is only 67 feet 6 inches (20-57 m.) thick. 



Aycliff 



The increased thickness of the Lower Gault seen in the Tilmanstone and Guilford 

 Collieries is maintained in the Dover area. Lamplugh & Kitchin (1911 ; 8) considered 

 from an examination of the Dover Colliery shafts that this was due to an expansion 

 of the higher beds of the Lower Gault, but the exploratory borings in the Dover area 

 for the Channel Tunnel show in fact that the reverse is the case. There are phosphatic 

 nodule beds in the cristatum Subzone comparable to those at Folkestone within 

 Bed VIII. The Gault in one of these borings, Dover No. 1 (Aycliff) (TR 294395), has 

 been described lithologically by Bisson {in Smart, Bisson & Worssam 1966 ; 101), and 

 the Lower Gault sequence is shown in text-fig. 32. 



The lautus Zone is indicated in Bed 11 by the presence of a Dimorphoplites sp. of 

 the chloris-bipiicatus group, and in another boring by Euhoplites opalinus. It is 

 considerably attenuated in comparison with Beds V-VII at Folkestone. Bed 10 has 

 yielded a crushed Dimorphoplites niobe which might indicate either the meandrinus, 

 subdelaruei, or niobe Subzones. Neither Bed 9 nor the bulk of Bed 8 yielded any 

 zonally significant ammonites but crushed Falciferella occurs in the lower 6 inches 

 (1-828 m.) of Bed 8 which suggest the intermedins Subzone or possibly the niobe 

 Subzone. Anahoplites of the intermedins group occur from 1 foot (0-304 m.) above 

 the base of Bed 7, and in Bed 6, definitely indicating the presence of the intermedins 

 Subzone. No subzonally diagnostic ammonites are known from Beds 5 and 4, but 

 Bed 3 contains phosphatised fragments of H. (H.) persnlcatns and H. (H.) of the 

 paronai group. This is the direct equivalent of Bed I (v) at Folkestone, the dentatns 

 nodule bed, classified with the spathi Subzone. It is highly probable that Bed 4 

 above is the equivalent of Bed I (vi) at Folkestone (p. 12). 



The particularly interesting feature of the sequence occurs in Bed 2. This bed is 

 classified with the lyelli Subzone, and contains species of Protanisoceras (P.) at only 

 12 and 15 inches (0-304-0-381 m.) below Bed 3, and species of Hopiites (H.) occur 

 throughout. This sequence bears comparison with the lower part of the Gault in the 

 Guilford, and Chislet Collieries where the lyelli Subzone is also well developed. At 

 Folkestone, the lyelli Subzone is very condensed and is represented within Bed I (iv) . 

 Whether the eodentatns Subzone is represented within the higher part of Bed 1 is 

 uncertain in the absence of ammonites but it is highly likely when one considers the 

 development of the lyelli Subzone here. The lower part of Bed 1 is probably equiv- 

 alent to the ' Sulphur ' Band at Folkestone. 



