Dr. FiTTON on the Strata below the Chalk. 133 



the chalk and the Weald clay is another very prominent feature of this part 

 of the country ; and though it arises^ in part, from the extensive denudation 

 at the entrance of the gorges where the principal rivers traverse the chalk 

 ridge, yet even if these were filled up, and the range of the downs between 

 the coast and Dorking rendered uniform, the space occupied by the lower 

 strata would be found to vary considerably*. The chief cause of this irregu- 

 larity is the difference of the angles at which the strata rise in different places ; 

 the heights also which the sands attain, having a proportionate variation. 



(41.) In the upper part of the Lower green-sand between Sevenoaks and 

 Godstone, a ridge or saddle can be traced for several miles, in a direction 

 nearly parallel to that of the central range of the Hastings sands, its course 

 being from about 10° south of west to 10° north of east. The places where 

 I have seen the structure of this ridge most distinctly, are on a line passing 

 from Montreal Park, through Sundridge, to the grounds of Brasted Place, in 

 the course of which several sections have been exposed. The strata consist of 

 yellowish and somewhat ferruginous sand, and " hassock," including beds of 

 a bluish stone, like that of the Boughton quarries and the vicinity of Folk- 

 stone : the fossils, also, are the same. 



The ridge just mentioned is probably continued eastward; but my obser- 

 vations in that direction did not extend beyond a place called Cold Harbour, im- 

 mediately on the west of Montreal Park, where the beds rise towards the south, 

 at an angle of about 20°; the bend, also, or summit of the ridge being there ex- 

 posed, on the verge of a small wood, but less distinctly than at Brasted Place, 

 hereafter mentioned. Its continuity, however, is in several places interrupted 

 by breaks or openings, from 50 to 100 paces in width, where a uniform 

 surface at a much lower level is continued from north to south, across the 

 direction; as if the ridge had been cut away in those places, or wide trans- 

 verse fissures had been partially filled up and levelled overf . The first of these 

 breaks is about sixty paces from west to east, and the summits of the heights 



* On the coast line the distance from the chalk at Folkstone Hill to the outcrop of the lower 

 green-sand at Aldington Corner, is about ten miles ; but from Lenham to the outcrop is not more 

 than two. A line parallel to the last, from Boxley, passing through Maidstone, is rather more 

 than six miles long ; but from Wrotham to the outcrop is less than four ; at Tandridge, on the 

 east of Godstone, less than one and a half; and at Reigate little more than one mile. On the west 

 of Reigate the lower green-sand again runs out four miles, to Leith Hill, which is 993 feet above 

 the sea. These details could not be expressed on the small map annexed to this paper : for 

 better illustration the reader is referred to Mr. Greenough's Geological Map of England, and 

 to the Ordnance Survey. 



t A remarkable break of this description occurs between two portions of wood immediately on 

 the north of the letter "y," of the word " Dry hill" in the Ordnance map. 



