i8 Proceedings of the 



Crossness, and Kentish Town, seem to confirm this view ; the opinion is 

 held by some geologists that coal will be met with on the flank of this 

 ridge. 



Mr. Gilford then referred more particularly to the formations found in the 

 immediate neighbourhood of Eeigate, beginning with the middle chalk con- 

 taining flints and lower chalk without them. The upper greensand which 

 underlies the chalk and chalk marl contains more or less of silica ; it is 

 sometimes phosphatic in its nature. It consists of alternate layers of about 

 two feet in thickness, first of a very hard stone called roofing stone, and then 

 of hearthstone ; a third layer of roofing stone, then successive layers of 

 hearthstone, roofing stone, and firestone, the last being a very good building 

 stone when properly laid as found in the quarry. Below this is found a soluble 

 silica, which is used at Farnham in manure making. A narrow band of fossils 

 is sometimes found occurring between the upper greensand and the gault, 

 which is the formation next in order. The gault is divided into 

 the upper, middle, and lower, and is found well developed at Folke- 

 stone. In this neighbourhood the lower greensand exhibits well the 

 various divisions known as the Folkestone, Sandgate, and Hythe beds. 

 The first includes the white sand and also red and other coloured sands, 

 which here occur as the most northern outcrop of this formation ; the white 

 sand sometimes attains a thickness of 30ft., and is important as an article 

 of commerce. The Sandgate beds are more clayey or loamy in character, 

 comprising the Fuller's earth and other clays. In this district these beds 

 form the crest of the ridge formed by the outcrop of the lower greensand. 

 The Hythe beds, which here follow a line to the south of the preceding, 

 contain a rag inferior to the Kentish rag found in these beds near Jlaid- 

 stone. Below these a bed of about 30 to 50ft. of brownish clay is met 

 with, known as the Atherfield clay. This is found near Woodhatch as n, 

 clayey sand ; it next becomes a sandy clay, and lower still a pure clay. 

 P.elow these beds the Wealden is reached, which in addition to clay con- 

 tains in some places beds of limestone, such as the Petworth marble, &c. 

 These are capable of taking a good polish. 



Mr. Gilford pointed out the advantages arising to this district from 

 the great variety of formations which crop out within a comparatively 

 small area ; this variety contributes to beauty of scenery, to salubrity, 

 and to fertility of the soil, for where different soils are contiguous 

 they become more or less mixed at the surface in the course of 

 agricultural operations, and such are often more fertile than either 

 one separately. Another advantage experienced here is the gi-eat 

 profusion and variety of the flora, certain plants affecting especially a 

 chalk soil, others a sandy one, and others clay. 



Mr. Gilford next referred to the water-producing powers of the 

 strata in this neighbourhood. We have one water-bearing bed in 

 the upper greensand, the water being upheld by the gault imme- 

 diately below. In a similar manner the weald clay enables the 

 lower greensand to retain its water, constituting it a natural reservoir. 



