H. A. Baker — Chamian Movement in East Kent. 401 



oolitic limestone with a pebbly base. "With regard to the Bathonian, 

 the record of the East Kent borings emphasizes Kendall's remark 

 that "the unconformable overlap of the Great Oolite is one of the 

 most marked features of Oolitic succession in Britain and in the 

 north of France ". The overlap of the Bathonian on the Palaeozoic 

 floor in East Kent occurs as a zone of X.W.-S.E. trend extending to 

 northward of Stodraarsh and Woodnesborough. In tracing the 

 isopachyte system of the East Kent Oolites the thicknesses 1 have 

 been taken from the base of the Inferior Oolite to the top of the 

 Portlandian, excluding the Purbeckian, since in the boring records 

 the latter is sometimes not separated from the Wealden. Since it is 

 only in the southern part of the area that Oolites higher than 

 Corallian occur, there is no danger of arriving at erroneous con- 

 clusions in consequence of the omission of the Purbecks. 2 The Oolite 

 isopachyte system proves very interesting (Map 2, Plate XXVII). We 

 notice again the marked north-easterly thinning of the formation, 

 with a strong tendency on the part of the isopachytes to assume 

 a N.W.-S.E. alignment within the zone of influence of the easterly 

 ridge. We also perceive once more an intimate relationship between 

 the isopachytes and the pre-Upper Cretaceous contours of the 

 Palaeozoic floor. The effect of the Deal-Bopersole disturbance upon 

 the isopachytes is very clear. There is, however, a particularly 

 interesting and instructive feature presented by these isopachytes 

 which appears to be missing from those of the Lias. In referring to 

 the general character of the pre-Upper Cretaceous contours of the 

 Palaeozoic floor, mention has been made of the abrupt interruption, 

 in the north, of the general north-westerly trend of the contours, and 

 the suggestion has been put forward that this may be due to 

 a movement (late Jurassic or early Cretaceous) of uplift in a new and 

 discordant direction — in fact, roughly east and west. It will be 

 noticed that in the north and west the Oolite isopachytes show 

 a marked tendency to deviate southwards and to approximate to an 

 E.-W. rather than a N.W.-S.E. direction. In the opinion of the 

 present writer this southerly deviation of the Oolite isopachytes may 

 be, in part, the result of denudation consequent upon the appearance 

 of an east and west ridge of Oolitic rocks. It has long been known 

 that such a ridge, extending westward beyond Streatham, existed in 

 late Jurassic or early Cretaceous times, and was subjected to extensive 

 denudation in Lower Greensand times and probably earlier. The 

 writer regards this axis of uplift as one of Armorican affinity. The 

 Oolitic ridge was partially submerged in Lower Greensand times and 

 completely so during Gault times. The deep borings at Bobbing and 

 Richmond showed the Lower Greensand resting on Oolites, while at 

 Stodmarsh, Streatham, and Meux's Brewery the Oolites are directly 

 succeeded by the Gault. 



To the north-east of the feather- edge of the Oolites, there is an 

 area, proved by the borings at Walmestone, Mattice Hill, and Ebbs- 

 fleet, where the Wealden overlap on the Palaeozoic floor occurs. To 



1 See Table II, p. 403, at end of paper. 



2 In point of fact, the inclusion of the Purbecks still further emphasizes 

 the north-easterly thinning of the Oolites. 



DECADE VI. — VOL. IV. — NO. IX. 26 



