Geological Society of London. 137 



Darent, and the excavation of the present valley then commenced. 

 There is a gap in the sequence between the pre-glacial drifts and 

 the earliest post-glacial drifts of the valley, which is probably 

 covered by the extreme glacial epoch. It was a time of erosion, 

 rather than of deposition in this area. Of the earliest drift of the 

 Darent valley, little has escaped later denudation. The bank of 

 coarse gravel on the hill on the west side of the valley between 

 Eynsford and Farningham, certain flint-drifts in the upper part of 

 the valley, and a breccia of chalk-fragments on the hill west of 

 Shoreham, may be referred to this period. 



iv. The High-Level or Limpsfield Gravel Stage. — The gravel at 

 Limpsfield occurs on the watershed between the Darent valley and 

 the Oxsted stream, but the author agrees with Mr. Topley that the 

 gravel belongs to the Darent system, and Westheath Hill may be 

 jjart of the original ridge separating the two valleys. This gravel is 

 post-glacial, and the denudation of the area had made considerable 

 progress at the time of its formation, for the Chalk escarpment rises 

 200-300 feet, and the Lower Greensand 100-200 feet above the 

 gravel-bed. The author traces outliers of this gravel down the 

 valley at lower and lower points to the Thames valley at Dartford, 

 and correlates it, not with the high plateau-gravel, but with the 

 High-level gravel of the Thames valley, and shows that its composi- 

 tion indicates that it is derived from the denudation of the Chalk 

 and Tertiary beds. Mr. A. M. Bell has discovered numerous 

 implements in ii, mostly of the smaller St. Acheul type, and the 

 author hopes that they will soon be described by their discoverer. 

 These implements agree in general type with the "Hill group" of 

 the Shode valley, and not with the older group of the Chalk plateau, 

 or those of the lower levels of the Thames and Medway. 



V. Contemporaneous Drift of the Cray Fa^/ei/.— Implements of this 

 age have been found by Mr. Crawshay, and by Mr. P. Norman, near 

 Green Street Green, in gravel which is more than 100 feet below 

 the Red Clay of the plateau. 



vi. BricTc-enrths of the Darent Valley. — These are traced along the 

 tipper course of the valley from near Limpsfield. They seem to 

 show glacial influence, and Mr. Bell has discovered a few impleuients 

 in them. The Limpsfield deposit is from 10 to 30 feet below the 

 adjacent gravel. Brick-earth, possibly of somewhat later date, also 

 occurs near Dartford. 



vii. Other Gravels of the Darent Valley: The Chevening and Dunton 

 Green Drifts. — The relations of the gravels grouped under this head 

 are more uncertain than those of the Limpsfield stage. Various 

 features in the gravels point to the temporary return of glacial 

 conditions during the period of formation of these and the brick- 

 earths ; and these are described in detail. 



viii. The Low-level Valley-Gravels. — The correlation of these is 

 also uncertain. West of Dartford is a bed corresponding with that 

 at Erith in which Mr. Spurrell found a palaeolithic floor. It con- 

 tains land- and freshwater-shells. The surface of the Chalk is here 

 festooned under a covering of the fluviatile drift. The author attri- 

 butes this festooning to the effects of cold. 



