IN THE ANGLO-PARIS BASIN 47 



Monks Bay. Above this, the basal beds of the Gault are occasionally well exposed 

 at the top of the cliff, but the remainder of the Gault is badly slumped in the Under- 

 cliff itself. Other sections are known from Ventnor, Steephill, and from Reeth Bay, 

 Niton and round St. Catherine's Point and are mentioned below. An ammonite 

 described by Spath as Anahoplites mimeticus (1925 ; 131, pi. X, fig. 7a, b) was alleged 

 to have come from the ' Carstone ' of Niton, Isle of Wight. However, the preserva- 

 tion of the holotype BMNH., C 30535 indicates that it is definitely not from the 

 Carstone but from an horizon in the Gault possibly above the spathi Subzone sedi- 

 ments ; it is possibly a species of Hoplites (H.) with a smooth outer whorl. The 

 specimen figured by Casey (1966 ; 547, text -fig. 207a, b, C. W. Wright Colin., 9983) 

 as Anahoplitoides mimeticus Spath which he states came from the top of the Carstone 

 (eodentatus Subzone), of Bonchurch, is preserved in a manner quite unlike any of the 

 material from the top of the Carstone and C. W. Wright has informed me that it was 

 picked up loose. It must come from a higher horizon in the Gault than the proved 

 spathi Subzone sediments. However, Hoplites (Isohoplites) eodentatus does occur in 

 the top part of the Carstone at Bonchurch but the preservation is the typical sandy 

 phosphate. It might be mentioned here that the specimen of Hoplites vectensis from 

 the Carstone near Niton mentioned by Spath (1925a ; 128 L.F. Spath Colin. No. 238 

 = BMNH., C 30555) is indeed from the Carstone and is an external mould without 

 the peripheral area. Nonetheless, it is almost without doubt a specimen of H. 

 (Isohoplites) . 



The few feet of Gault immediately overlying the Carstone at Monks Bay has 

 yielded, from a fawn band, crushed and partly phosphatised Hoplites (H.) spp., 

 specimens of which are in the British Museum (Nat. Hist.) L. F. Spath Colin. An 

 external mould of a Beudanticeras sp. in an identical matrix is preserved in the 

 Institute of Geological Sciences (GSM., Zn 1483 also L. F. Spath Colin.) and indicates 

 the presence of the lyelli Subzone. A pyritic specimen of Lyelliceras is in fact known 

 from this locality and was figured by Spath (1931 ; 320 pi. XXXIII, fig. i5a-c, 

 BMNH., C 32845). Further evidence of the presence of sediments of lyelli Subzone 

 age is provided by ammonites from the basal Gault near the Gas House, Gas House 

 Hill, Ventnor (SZ 56857747) preserved in the Sedwick Museum. These consist of 

 black brittle phosphate steinkerns without the shell, typical of the lower fawn band, 

 and include Beudanticeras sanctaecrucis and Hoplites (H.) spp., one of them (B 42586) 

 with pyritic inner whorls like that of the Lyelliceras mentioned above. C. W., & 

 E. V. Wright have recorded Protanisoceras moreanum from west of Luccomb Chine 

 (1942 ; 286). 



More definite information about the higher part of the Gault is provided by the 

 section in the cliff SW. of Steephill Cascade, Ventnor (SZ 55467707). Here the 

 Gault dips seaward becoming much steeper in the foreshore landward of an old 

 slipped mass. Dark grey gritty pyritic clay with rolled pieces of phosphatised 

 Hoplites (H.) spp. occurs along the axis of the ' fold ' and is overlain by sparsely shelly 

 clay in which ammonites have yet to be found. The cliff behind these foreshore 

 exposures is deeply weathered at this time. 



