IN THE ANGLO-PARIS BASIN 45 



Bed 5 of the Carstone contains crushed filmy shells of ribbed ammonites. Very 

 rarely these are partly phosphatised and can be identified as Hopiites (Isohoplites) 

 spp. including H. (I.) eodentatus (e.g. BMNH., C 73358 author's colln., figured Casey 

 1965 ; 538, text-fig. 202 g.h.) indicating an eodentatus Subzone age. Beds 1-6 of the 

 Gault have not yielded fossils and may represent the lyelli Subzone known to be 

 present in the Ventnor area to the south. Beds 7-1 1 can definitely be classified with 

 the spathi Subzone. Bed 7 contains crushed pyritic ammonites, some partly phos- 

 phatised, including the typical H. (H.) spathi and H. (H.) dentatus marking the base 

 of the spathi Subzone. Bed 8 also contains crushed Hopiites (H.) spp. with pyritic 

 tests which decompose very rapidly on exposure. Beds 9-10 have not yielded fossils, 

 but Bed 11 has yielded a few fragments of large Hopiites (H.) which still suggest the 

 lower part of the spathi Subzone. No fossils were found in Beds 12-14. 



(c) Compton Bay 



In view of Kitchen & Pringle's statement that no Lower Gault is present in Comp- 

 ton Bay (1922 ; 161) it was particularly fortunate that a good section has been ex- 

 posed during recent years. The true Gault here was stated by Strahan (in Bristow 

 et at. 1889 ; 63) to be 95 feet (28-956 m.) thick excluding the passage beds to the 

 Upper Greensand but this is far in excess of the true figure. The very high angle of 

 true dip seen in the cliff, levels off sharply at no great depth below beach level due to 

 a slight flexure and change in direction of apparent dip. On a very accurate 

 measurement based on the detailed sequence given in text-fig. 20, the thickness 

 is little more than 65 feet (19-812 m.). 



The phosphatic nodules at the top of Bed 8 of the Carstone have yielded Hopiites 

 (Isohoplites) eodentatus indicating that Subzone. No ammonites have been found in 

 either Beds 1 or 2 of the Gault and their exact Subzonal age is unknown. However, 

 the species of Hopiites (H.) in Bed 3 indicate the basal part of the spathi Subzone and 

 it is possible that both Beds 1 and 2 are of lyelli Subzone age. Apart from Bed 3, the 

 only other ammonites found were crushed Hopiites (H.) sp. at the base of Bed 10, at 

 which point a shelly facies appears. One is tempted to compare this junction be- 

 tween the pyritic facies below and the shelly facies above, with a similar junction in 

 the spathi Subzone sequence in the Nyewood-Wrecclesham area of the outcrop in the 

 Weald. However, such a correlation may well be more apparent than real. Beds 3 

 to the base of Bed 10 can, therefore, be classified with the spathi Subzone. How much 

 of the overlying sediments belong to the spathi Subzone is not yet known, as also 

 whether any other Middle Albian Subzones are represented. However, there is no 

 doubt that there is a substantial thickness of ' Lower ' Gault present at Compton 

 Bay. 



(d) Ventnor to Niton 



A complete section of the Carstone is exposed in the sea-cliff extending from 

 Dunnose south-westwards to the esplanade at Bonchurch ; the stretch of coast named 



