Dr. FiTTON on the Strata below the Chalk. 147 



Among the looser sandy materials of Holloway-hill are spongy concretions, which show, when 

 moist, the same vermicular structure as at Tilburstow-hill, 



Blackheath, south-east of Guildford, seems to have been once a continuation of the sands near 

 Godalmin''. Its top is nearly level with the chalk range, but lower than Martha's Chapel hill. 

 On the south, the ground descends to Farley Heath, with a sort of escarpment like that of Crooks- 

 bury and Farnham commons, hereafter mentioned ; and the road thence by Farley-green to 

 Hound-house is in a richer sand, supporting pools in several places, and probably belonging to the 



middle group. 



Crooksbury Common seems to consist of the upper members of the formation, impending, like 

 an outcrop 150 to 200 feet thick, over the valley of the Wey, between Elstead and Tilford ; and 

 on the south of the stream the heights of sand are renewed. Farnham Common is analogous to 

 that of Crooksbury, and apparently a continuation of the same plateau, deeply cut through by one 

 of the principal streams of the Wey. On the south of these, is the lower tract of Frensham and 

 Thursley commons, and thence the ground rises rapidly towards Hindhead, the ascent consisting 

 of sand deeply trenched into channels. A conspicuous group of barren, somewhat conical hills, 

 on the south of Frensham Common, called the " Devil's Jumps," is apparently the remaining por- 

 tion of a stratum of sand reduced by abrasion to the present irregular form ; and the pebbles and 

 rolled masses on Thursley Common, immediately on the north of Hindhead, are sandrock, passing 

 into chert, which seems to be unmixed with other matter, and to be the debris of the beds now 

 removed. 



(61.) Hindhead. — The crest of Hindhead is on the north-east of a de- 

 pression called the ''Devil's Punchbowl/' round which the road is conducted. 

 The highest part of the curve, or anticlinal bending, of the Lower g-reen- 

 sandj seems to be just at a point where the new road, on a lower level than 

 the old, has exposed a face of 10 to 25 feet in height. The flexure is 

 very slight, but sufficiently perceptible, occurring in such a place, to be de- 

 serving of notice. The strata consist of soft sandrock, containing con- 

 cretions, and nearly continuous beds of chert, passing into chalcedony, of 

 various shades of yellow and brown ; with occasional layers of bright yellowish 

 sand, in which the lines of false stratification are conspicuous. All over Gray- 

 shot Down the subsoil is a soft, loose sand of the same description. 



(62.) The whole of the tract here occupied by the sands, though not 

 unpicturesque, is wild and barren in its aspect, destitute of wood, producing 

 only ferns, heath, and furze. The surface is in fact, to this hour, nearly 

 such as it may be conceived to have been when first uncovered by the 

 departure of the sea; and its structure is just what may be imagined to 

 result from the levelling effect of water under the influence of motion 

 of no great violence. In crossing this desolate region by the main road 

 from London to Portsmouth, it is difficult to believe that we are only forty 

 miles distant from the capital, and midway to one of the chief naval 

 establishments of the empire : but the nature of the soil eff'ectually prevents 

 improvement, and it is not improbable that this tract may remain for centuries 



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