GEOLOGY 



IF our study of the geology of Kent were to be confined to the 

 strata which constitute the surface only, we should find its rock 

 structure so faithfully reflected in its simple physical features that 



a knowledge of the shape of the ground would almost necessarily 

 convey an idea of the broader outlines of its stratigraphy. The rising 

 ground south of the Thames, composed of the soft Tertiary clays and 

 sands ; the bold range of the North Downs, formed by the Chalk 

 emerging from beneath these and terminating southward in a steep 

 escarpment ; the hollow at the foot of this range, where the underlying 

 Gault Clay reach the surface ; the lower range of hilly ground running 

 parallel to the Downs, composed of the harder beds of the Lower 

 Greensand, which come next in downward stratigraphical succession ; 

 the broad plain south of these hills, underlain by the Weald Clay ; and 

 finally the pleasant rising ground along the southern margin of the 

 county, where the sands and sandstones of the Hastings Series emerge 

 from beneath the Weald Clay — all these features of the surface are 

 directly due to the character of the strata and to the direction in which 

 the beds are sloping. 



As a glance at the accompanying geological map will show, the 

 different formations extend approximately east and west in more or less 

 continuous belts across the county. They are prolonged beyond its 

 borders in nearly the same direction westward through Surrey and into 

 Hampshire, their course or ' strike ' being boldly indicated by the 

 prevalent lie of the hill-ranges. 



But our investigation must not be limited to the rocks to which 

 the surface features of the county are due ; for we have of late years 

 learnt much regarding the strata buried deeply underground, that have 

 no effect upon the present outline of the land. Indeed our knowledge 

 of the deep-seated geology of Kent has recently made more important 

 advances than that of almost any other part of the British Islands, in 

 consequence of a series of deep borings carried down in search of coal, 

 which have given definite information as to the downward succession of 

 the strata to a great depth. 



Thus, of the three main divisions adopted for the fossiliferous rocks 

 in the geologist's time-scale, the beds occurring at the surface in Kent 

 represent portions only of the Cainozoic or Tertiary and of the later part 

 of the Mesozoic or Secondary division. We now know however that 

 the strata beneath the surface range downward to the base of the 



