IN THE ANGLO-PARIS BASIN 61 



(iii) DEVIZES TO THAME (OXON) 



(a) Badbury Wick (Wiltshire) 



There is no information available at the outcrop between Devizes and the Swindon 

 area, a distance of about 18 miles (text-fig. 18). Messrs Hill's of Swindon Ltd's pit at 

 Badbury Wick has shown a section in spathi Subzone sediments for some years, but 

 in 1967 the pit was deepened and exposed sediments of lyelli Subzone age. The 

 sequence now exposed is shown in text-fig. 27. Although this is the first time in this 

 century that a lyelli Subzone sequence has been well exposed in Wiltshire, it is 

 apparently different from that of Caen Hill and further south-west (text-figs. 26 & 25). 

 A working near the present pit was mentioned by Ramsey, Aveline & Hull (1858 ; 



33)- 



Beds 1 to 6 contain a typical lyelli Subzone fauna but in contrast to Small Dole 

 (p. 38) Lyelliceras lyelli and Brancoceras spp. occur only infrequently and the bulk 

 of the fossils are crushed. The commonest ammonites are the heteromorphs such as 

 Protanisoceras (P.) barrense and P. (P.) alter notuberculatum together with Beudanticeras 

 laevigatum, and Hoplites (H.) spp. The facies is a shelly one, albeit sparsely in places, 

 with in general a better developed benthos than that seen in Sussex. Ammonites are 

 apparently rare in Bed 6 which otherwise contains very well preserved but fragile 

 bivalves and gastropods. That it still belongs to the lyelli Subzone is indicated by 

 the occurrence of Beudanticeras spp. as well as Hoplites (H.) spp. 



Beds 7 to 11 are classified with the spathi Subzone. Bed 7 shows the major change 

 in the ammonite fauna which marks the base of the spathi Subzone, and these now 

 consist of species of Hoplites (H.) such as H. (H.) dentatus and H. (H.) maritimus sp. 

 nov. associated with the bivalve Inoceramus concentricus in shell seams. The 

 benthonic fauna is very reduced in comparison with the lyelli Subzone sediments 

 below. Bed 8 contains the same fauna with individuals partly phosphatised with the 

 shell, while in Bed 9 the fossils are again crushed flat. In Beds 10 and 11 the shells 

 are replaced by pyrite and the non-ammonite element of the fauna becomes un- 

 common. No fossils have been found in Bed 12 and its age is uncertain. 



The lithological sequence in the spathi Subzone is quite different from that of Caen 

 Hill, Devizes (text-fig. 26), where there is no pyritic facies in any part of the spathi 

 Subzone sequence and a good benthos is present throughout. The sequence at 

 Badbury in this Subzone is surprisingly reminiscent of that exposed in the Nyewood- 

 Selborne area of the western margin of the Weald (Owen 1963a). However, there, 

 the situation is somewhat reversed, the pyritic facies encompassing the sediments up 

 to and including the two ferruginous marly bands, the shelly facies prevailing in the 

 higher beds. 



(b) Badbury to Thame 



The Gault outcrop in the Vale of White Horse (Berkshire) has been discussed 

 principally by Hull & Whitaker (1861), Jukes-Browne (1900 ; 268) and Arkell (1947a ; 

 167-9). No sections now exist either at Uffington or in the area N. of Childrey. 

 Arkell recorded the discovery of specimens of Dimorphoplites by Mr. C. W. Wright in 



