﻿1850.] 



TRIMMER ON THE ERRATICS OF KENT. 



35 



surface of the chalk, at its junction with 

 the soil, has been worn into pipes and 

 cavities, some of which are four or five 

 feet deep. Some of the road-cuttings 

 show light yellow sandy loam, mixed 

 with angular flints and eocene pebbles, 

 resting immediately on the chalk. A 

 little north of Firby Farm, marked on 

 the Ordnance Map, a gradual slope com- 

 mences to a valley opening into that of 

 the Thames. The road from Darenth 

 to Longfield and Cobham runs through 

 the bottom of the valley. About three 

 furlongs west of Longfield, by the side of 

 the lane leading to Hartley, which as- 

 cends the western side of the valley, a 

 cutting at the new Parsonage House of 

 Hartley, now building in a wood marked 

 on the Ordnance Map, has laid open an 

 instructive section of the soil and subsoil 

 above the chalk, the most material por- 

 tion of which is exhibited in the accom- 

 panying section. Where the section ap- 

 proaches the summit and the surface of 

 the chalk rises, the soil consists of loam 

 and clay-loam varying from one and a 

 half to four or five feet with the irre- 

 gular surface of the chalk. In imme- 

 diate contact with the chalk is a layer of 

 dark, ferruginous, and tenacious clay, 

 from a few inches to two feet thick, 

 which also fills cavities in the chalk, 

 and passes upwards into clay-loam. In 

 some parts there are collections of re- 

 constructed chalk, containing seams and 

 patches of the same kind of ferruginous 

 clay as that interposed between the sur- 

 face-soil and the clay which rests upon 

 the chalk ; and in one of the pipes are 

 alternations of clay with calcareous 

 matter. Large unabraded flints and 

 rounded flint pebbles of the eocene series 

 are dispersed through all these deposits, 

 and in one part shown in the section, 

 there are accumulations of the small 

 rounded pebbles of the eocene strata. 



As the surface of the chalk sinks to- 

 wards the valley, and the superficial de- 

 posits deepen, they become more blended. 

 In the lane between the corner of the 

 d 2 



