160 F. L. KitcJdn cC; J. Pr ingle — TJie U'p'per Gault in 



Oault transgression. While Professor C. Barrois ascribed most of 

 the transgressive Selbornian strata of South Dorset and Devon to 

 the Upper Gault (his zone of A. inflatus), the late A. J. Jukes-Browne 

 thought it probable that the Lower Gault is represented there in 

 the lower beds.^ In the case of the " Red Chalk " (or Red Rock) 

 of Norfolk and Lincolnshire, conflicting opinions as to its age have 

 given rise to such confusion and doubt that the close bearing of this 

 deposit on the subject now under discussion appears to have been 

 generally overlooked. Professor Barrois, we must mention, 

 considered the Red Chalk of those counties to represent the Upper 

 Gault ; and so far as its lower three-quarters are concerned, we are 

 satisfied that his correlation was the correct one. We shall state 

 reasons for regarding the uppermost portion of the Red Rock at 

 Hunstanton as part of the overlying Chalk. 



The result of our investigation, so far as it has proceeded, has been 

 to unify the facts and to convince us that one general movement 

 was responsible for a transgression round the border-regions of the 

 main basin of Gault Clay deposition in England. A consideration 

 of all the palseontological evidence leads us to place the date of this 

 movement at about the close of Lower Gault time. We think it 

 probable that the character of Price's nodular " Junction Bed " at 

 Folkestone (Bed VIII), which contains nodules and fossils in remanie 

 condition, may be connected with the disturbance that gave rise 

 to the transgressive extensions of the Gault in the marginal regions 

 of the English area of deposition. The magnitude of this and 

 subsequent movements and the widespread nature of their effects 

 are shown by the occurrence of transgressions of the Upper Gault 

 (Upper Albian) and lowest Cenomanian deposits in France and 

 Belgium, in Africa, and in other distant regions. 



II. ClL\RACTERS OF THE GaULT IN CERTAIN LOCALITIES. 



Kent and Surrey. — In these counties, where the Lower Gault is 

 present in normal development, always resting on the mammillatus- 

 bed, there has not been observed any indication of the movement 

 which produced the Upper Gault overlap, except perhajDs at Folke- 

 stone, as mentioned above. In West Kent and in Surrey the Gault 

 Clay is thickly developed and the detection of any efiects of the 

 movement at a particular level in the series is scarcely to be 

 expected there. At the same time, there are indicationsof subsequent 

 results in the introduction of an arenaceous facies in the rostratus- 

 zone at the western limit of Kent and in Surrey. This change was 

 doubtless connected with the process of shallowing which so afEected 

 the character of the sediments deposited subsequently to the date 

 of the overlap in more westerly counties. 



The Isle of Wight. — Inland exposures of the Gault are rare and 

 unsatisfactory. In the hollow between RedclifE and Culver Cliff, 



^ The Cretaceous Rocks of Britain, vol. i, " The Gault and Upper Green- 

 sand of England " : Me^n. Geol. Surv., 1900, p. 145. 



