Dr. FiTTON on the Strata beloio the Chalk. 145 



The quarries on the roadside between Guildford and Shalford, disclose a 

 o-ood section of the chalk, with numerous flints, dipping at an angle of about 

 5*^ or 6°, a little to the west of north ; and on the opposite side of the Wey, 

 beneath St. Catherine's Hill, the relative position of the lower strata is very 

 well displayed. 



(58.) The Hog's-hack. — The remarkable ridge called the '' Hog's-back," 

 which runs from Guildford to a point about two miles from Farnham, has 

 been produced evidently by an upthrow of the chalk, and the breaking 

 off of the southern portion of the curve. The inclined position of the 

 remaining side of the flexure is very well seen at the western extremity of a 

 lar"-e chalk-pit between Guildford and Puttenham, where the strata dip 

 towards the north, at an angle of about 30°. The upper beds are very 

 white, with courses of the usual dark flint nodules ; and a remarkable 

 feature in this quarry, is the distinctness with which the chalk is divided 

 into masses approaching to a rhomboidal figure, by seams oblique to the 

 stratification ; the angles of the portions thus bounded, standing out in 

 the face of the cliff, like splinters in the shattered fracture of a crystal. 



The Upper green-sand forms a slight projection along the foot of the Hog's-back ; the Gault, 

 a corresponding narrow depression along its whole length ; and the Lower green-sand rises so 

 rapidly beneath, that one or many inflections are necessary to account for its wide extent to the 

 south. In approaching Farnham, the gault, near its contact with the sands, abounds in nodules 

 containing a large proportion of phosphate of lime ; resembling those of the vicinity of Folk- 

 stone (13.). The upper beds of the Lower green-sand rise, like the chalk, at a very high angle, 

 and must have been bent suddenly in an opposite direction, since they are now continued, with a 

 moderate inclination, several miles to the south. Along the north of Puttenham Common, the 

 sand is reddish, and very like that of Red-cliff at Sandown Bay, in the Isle of Wight. A nearly 

 continuous surface of the sands extends towards the south from Compton to Hurtmore, and 

 North Brook Place, and is resumed on the south of the river, through Westbrook and Upper 

 Eashing. It is again cut through by the stream, which the London road accompanies, on the 

 south-west of Godalming ; but recurs, in the heights south-east of the town, from Holloway-hill 

 and Crown Pit to Munstead Heath, which seems to be nearly on a level with the top of the 

 Hog's-back. On the west, the upper beds of sand form several prominences, among which 

 Crooksbury-hill is the most conspicuous ; their elevation having probably been the effect of pro- 

 trusion. On the south-west of Crooksbury, the upper sands seem to expand, and to occupy a 

 still wider horizontal space in that part of the denudation which corresponds to the less inclined 

 beds about Farnham. 



(59.) The general thickness of Lower green-sand here seems to be nearly 

 the same with that of the coast, and may be taken as between 350 and 400 

 feet ; though, from its superficial extent, a much greater thickness might 

 be ascribed to it, if the disturbance and inflexion which it has undergone 

 were not kept in view. There can be no doubt, both from the features of the 



VOL. IV. SECOND SERIES. U 



