IN THE ANGLO-PARIS BASIN 13 



Since Spath completed his Monograph, our knowledge of the Lower Gault at 

 Folkestone has been increased by Casey (1950) and the author (Owen 1958 ; 1963a). 

 Bisson (in Smart, Bisson & Worssam 1966 ; 56-58) has given an account of the 

 section, but this is based essentially on Jukes-Browne. The revised section of the 

 Lower Gault, given in part by me in 1963 (1963a ; 36-38) and in full in text-fig. 2, is 

 the first new account since Price (1880). It is slightly thicker than that of Price, but 

 this is probably due to his section being further out from the modern cliff-line, the 

 seaward slope of the land at Copt Point producing a slightly thinner sequence due to 

 creep at the cliff of Price's day. 



Casey (1950 ; 272-3) divided Bed I into four sub-divisions corresponding to (i) the 

 ' Sulphur Band ', (ii) the ' Greensand Seam ', (iiia) the dentatus nodule bed, and 

 (iiib) the remainder of the clays. He classified the whole of the ' Greensand Seam ' 

 with the inaequinodum Subzone, later (e.g. in Worssam et al. 1963 ; 59) replaced by 

 the index Hoplites (Isohopiites) eodentatus. The dentatus nodule bed and the lower 

 part of the overlying clays were, following Spath, classified with the spathi Subzone, 

 and the upper part of Bed I with the intermedins Subzone. He concluded that the 

 benettianus Subzone (i.e. the lyelli Subzone) was probably absent (see also in Worssam 

 etal, 1963 ; 59). 



Subsequent work has shown that Casey's subdivisions are too broad and a more 

 detailed notation is given by me (Owen 1963a ; 36-38, 49) and in text-fig. 2. 



Fossils are rare in the ' Greensand Seam '. The specimens of Hoplites (Isohopiites) 

 in the Institute of Geological Sciences (GSM 83165-6 Spath Coll.) are angular frag- 

 ments like the nodules of I(ii) which is here classified with the eodentatus Subzone. 

 Bed I(iii) has not yielded fossils to me, but in I(iv) at a depth of 2 inches (0-05 m.) 

 beneath the dentatus nodule bed, I have collected, apart from the specimen of 

 Hoplites (H.) cf. baylei Spath figured by me (1963a ; 37, pi. 3, fig. 3), a fragment of 

 Beudanticeras sp. indet. together with one specimen of Neohibolites minimus (Miller) 

 and a few indigenous and very delicate bivalves. The association of Hoplites 

 (Hoplites) and Beudanticeras indicates the lyelli Subzone. From a knowledge of the 

 lyelli Subzone successions at Small Dole (p. 35), Swindon (p. 61) and the Aube (p. 91), 

 the writer is firmly convinced that the specimens of Hoplites (H.) aff. benettianus 

 which occur rarely in the spherical phosphatic nodules immediately beneath the 

 dentatus nodule bed (Owen 1963a ; 37, pi. 3, figs, ia, b ; 2a, b) are of late lyelli Sub- 

 zone age. The presence of this Subzone at Folkestone is not surprising because it is 

 well represented in the Gault of the Guilford (Waldeshire) Colliery shaft (p. 76) about 

 7 miles (11-25 km.) from Copt Point, and in the Aycliff boring (p. 78). 



The classification of the remainder of Bed I has been discussed by the writer 

 already (Owen 1963a ; 37-38, 49), and it is only necessary to question one statement 

 made by Casey (in Hancock 1965 ; 247) that Anahoplites intermedins comes in a foot 

 or two above the spathi nodule bed as a minority element in a fauna still dominated 

 by Hoplites. If this were the case, then the Folkestone section would be unique. 

 Species of Hoplites (H.) occur crushed in Bed I (vi) up to a height of 3 feet 2 inches 

 (0-96 m.) . Higher up, ammonites are absent or very rare until one reaches the base of 

 I (vii), at which level Anahoplites intermedins appears. At Folkestone, as at most 

 other localities in the Weald, there is a gap in the ammonite fauna between un- 



