England and the " Bed Clialh " of the Eastern Counties. 163 



have been accurately described by Sir A. Strahau (op. cit., p. 157). 

 While visiting these coast-sections in Dorset we received much 

 kind assistance from Capt. E. Gray. 



Although the great rarity of ammonites and the development of 

 a sandy facies in the Gault of this neighbourhood deprive us of the 

 best criteria for correlation, we are of opinion that the interruptus- 

 zone is unrepresented. The total absence of any of its distinctive 

 faunal elements is alone a significant fact. This view is greatly 

 strengthened by the occurrence of an isolated patch of interruptus- 

 Gault bound up intimately, as usual, with the mammillatus-hed at 

 its base, at Okeford Fitzpaine, in North Dorset.^ At that spot there 

 is displayed in some 8 feet of fossiliferous strata the familiar normal 

 faunal type of the true lowest Gault Clay of other parts of 

 this country, which is absent, however, at the base of the Gault 

 where it rests unconformably upon the Kimmeridge Clay at neigh- 

 bouring localities and throughout the northern part of the county. 

 Light is thrown upon the matter by Mr. Newton's description of the 

 section at one time well exposed at Okeford Fitzpaine, in which the 

 upper part of the 19 feet of beds referred by him to the interruptus- 

 zone is described as dark-grey, micaceous and sandy clay ; and 

 particularly by the fact that some of the fossils figured by him are 

 Upper Gault and not Lower Gault shells (species of Jnoceramus 

 and Trigonia ; large form of Lima [Mantelluni) gauUina Woods). It 

 seems clear that the inferruptus-zone is there only rejDresented by a 

 thin local patch which has escaped denudation and is overlain by 

 the transgressive Upper Gault, which alone is present in the neigh- 

 bouring country to the north, just as in the coast-sections. 



We have not yet been able to examine the Gault of Black Ven or 

 its equivalents to the west. At Black Ven the Gault rests upon the 

 Lias, and the assignment of its lowest beds to the Lower Gault by 

 those who have described it is not supported by any evidence. ^ On 

 the South Devon coast, near Seaton and Sidmouth, C. J. A. Meyer 

 obtained Inoceranms sulcatus in his Bed 2, associated with a 

 lamellibranch-fauna closely akin to that of the Blackdown Green- 

 sand.^ Neither in this bed nor in the thin basal Bed 1 has there been 

 found anything to suggest a Lower Gault age. At Blackdown and 

 Haldon there is a closer approach to shore-conditions, with a sandy, 

 shelly facies. No distinctive Lower Gault fossils have been found 

 at these localities. The well-known fauna which comes in above the_ 

 barren basal sands at Blackdown includes species of zonal value such 

 as Schloenbachia varicosa, another Schloenbachia, well keeled, and 



^ R. B. Newton, "An Account of the Albian Fossils lately discovered at 

 Okeford Fitzpaine, Dorset " : Proc. Dorset Nat. Hist, and Ant. Field Club, 

 ■vol. xviii, 1897, p. 66. 



^ A. J. Jukes-Browne, op. cit., p. 188. W. D. Lang, "The Zone of 

 Hoplites interruptiis (Bruguiere) at Black Ven, Cbarmouth " : Geol. Mag., 

 1904, p. 124. 



^ C. J. A. Meyer, " On the Cretaceous Eocks of Beer Head and the adjacent 

 ClitT-sections " : Quart. Journ. Geol. Soc, vol. xxx, 1874, p. 372. 



