208 



THE CTVIT. ENGINEER AND ARCFITTECT'S JOURNAL. 



[Junk, 



Shiift .sunk by tlie side of an old chalk pil, in a field opposite 

 the Star Inn, Merstham, ;i74 feet, above lii!,'li M'alcr. 

 ft. in. 



15 Stronof hmipy chalk much sliakcn 

 vertical lissnres. 

 4 Fine stronjj chalk. 

 2 Layer of plate Hint. 

 7 Firm rock chalk. 



'>• 



26 2 



Rock chalk continnes — 



Shaft sunk at the end of a plantation in the parish of Chipstead 



on the road from London to Brighton, :V20 feet above hii^li 



water. 



ft. 

 8 

 (■) 

 3 



23 



in. 

 

 

 

 



liOam and flint gravel. 

 Clean clayey loam. 

 Loam and Hints. 

 Solid chalk. 



40 



Rock chalk eontimies : — 

 Boring at Dean's Farm commenced 

 higli water : — 



ft. in. 



10 



21 



nf snrfiee 402 feet above 



Loan and gravel. 

 Chalk much shaken. 



31 



Solid chalk below this depth. 



Boring in Coulsdon Parisli commenced 292 feet above liigh 

 water: — ° 



ft. 



6 



20 



m. 

 

 6 



Chalk marl. 



Chalk much shaken. 



20 6 



Solid chalk below this. 



Boring in a field belonging to Sir William .Toliffe in the parish of 

 Merstham, commenced at S^S feet above liigli water ■ — 

 ft. in. 



11 Flint and grave!, 

 2 Loose sanil. 

 15 Chalk, with flints. 

 47 Hard chalk. 







Boring at a spot 400 feet above liiMi-waler mark ' 

 ft. in. 



IG Flints and gravel. 

 42 Hard chalk. 



58 



From the above it will be seen that the chalk of IMei'st ham con- 

 sists mainly of the inferior beds of rock chalk. One of the borings 

 mdicates a layer of flint, and this is, probably, the lowest of those 

 layers which are exposed in the quarries of S'niitham Bottom, near 

 Croydon. It is true that flints are abundant in the upper part of the 

 chalk, even al Merstham, but they are in a loose, nnstratified state, 

 and have evidently been washed from th.eir natur.al position, which 

 is considerably higher than where found at present. Below the chalk 

 marl in which the' loose Mints are imbedded, the rock chalk is at first 

 considerably shattered, but at a greater depth is extremely firm, and 

 might be used for building where it can be protected from the action 

 of air and water. 



Numerous quarries are worked in theneighbom'hood of Merstham, 

 and the excellent ipiality of the lime burnt from this chalk is well 

 known. In the quarries south of Merstham tlie chalk is much shat- 

 tered by vertical fissures, which appear to separate the whole face 

 into rectangles of about six inches wide. Considerable quantities of 

 debris have fallen from the face of the chalk which rarely stands up- 

 right for any length of time. In one quarry which 1 'h.ave visited 

 the depth of chrlk i.s about ,50 feet, and the slope nearly one-tliird to 

 one, and in nnothrr. --thpvn.^arer (oATerstham, but .stiU on the .south 



side, the chalk face which here also is about M feet in heiglit, stands 

 upright from the bottom to within 20 feet of the top. The fire-stone 

 is obtained at Merstham from galleries worked under the chalk, and 

 extending a considerable distance under ground. A large shaft has 

 also been sunk down to the fircstone, and considerable quantities have 

 been brought to the surface, and used for the ornamental work of 

 Lord Monson's house at Gatton, from ^^hich estate the fircstone is 

 Iirincii<ally obf.ained. 



A great deal of discussion arose during the struggle between the 

 various Brighton lines in the session of l!^37, as to the best method of 

 forming the chalk excavalion.s. It was argued by one parly that a slojie 

 of from -, to 1, to 1 to 1 should be adopted for the cuttings, while 

 another ]iroposed to make the sides nearly vertical, contending that 

 aslope of one-sixth to 1 was s\ifficient, A third party proposed a 

 system of benching at about every 1,'j feet in height, tlie successive 

 steps to be vertical, and to be faced with rock-chalk. The accom- 

 panying drawing (fig. 4) exhibits the two designs proposed respec- 

 tively by Mr. Hastrick and by Mr. Gibbs. 



Of the Oxted Pass, which was selected for the south-eastern line, 

 I am not able to say much. The Oxted chalk, on the soutli side of 

 the summit, is of a brittle, friable nature, and does not appear to 

 stand well in the quarries at a less slope than about 1 to 1. This 

 may be obsi?rved in the great Oxted cpiarrics, and in a small pit 

 .about 40 yards from the line. Thegault lies up very high beyond the 

 chalk at this place, and several springs maybe observed at the junc- 

 tion of the gault and the fircstone. Close to the road leading over 

 the chalk hills at Oxted is the celebrated Riddlesdown quarry, the 

 properly of Mr. Atkins. The deepest face of chalk in this quarry is, 

 standing at a slope, something steeper than i to 1. The chalk here 

 is in very large blocks, and contains no flints. The frost occasion- 

 ally brings down masses of this chalk, the face of which, after a fall, 

 presents a rugged ii'regnlar appearance, in consequence of the fall- 

 ing out of occasional loose blocks, while others have been too firmly 

 wedged in to be thrown down. In addition to the preceding princi- 

 pal passes, a number of others have been tried, mainly with the 

 object of discovering a spot where the chalk, although rising to a 

 considci'able altitude, should yet be narrow in the direction of the 

 line intersecting it. Thus, admitting that a tunnel were necessary, 

 il will obviously be possible that the very highest summit of the 

 chalk may be found most eligible, because the ridge at this summit 

 may be narrower and more compressed, thereby occasioning, at the 

 ends of the tunnel, less work than on a line which penetrates a much 

 more dejiressed part of the range. Although certainly not justified 

 in saying that tliis condition was answered by any of the trial-lines 

 through the more elevated parts of the Surrey hills, it may neverthe- 

 less lie useful to record the result of these trials, one of which — the 

 Oxted — has been already mentioned, the others being at Betchworth, 

 and at Bletchingly. The Betchworth line was intended to cross over 

 a corner of Epsom race-course, touching the park of Baron de 

 Tessier, and thence passing between the villages of Betchworth and 

 Buckland, The suumiit of the railway in the chalk was ."JUO feet 

 above liigh water. The chalk of Betchworth is remarkably dry, and 

 ajipears to be firmer, and not so much shalicn as that of Mer.stluuu. 

 AVitli respect to the line by Bletchingly, I am unable to give any- 

 thing more than the height of the summit which was tried, and 

 which, in connexion with the approach on each side, was found so 

 comparatively ineligible, that all idea of carrying a line in that direc- 

 tion was immediately abandoned. This smnmil is at the south-east 

 corner of Piatt Green, on the road leading thence to Tupwood Com- 

 mon ; height above high water mark, / 30 feet. 



The first ]i.i-:s in the South Down range which I propose tonotice, is 

 that thrnughwTiich 1 lie River Adur flows to its f);i/)OHc/(HrcatShi>reham. 

 The lines through the Adin- valley entered the chalk at Beeding, 

 about .') miles from Shoreham, and, as the tide flows in the Adrcr as far 

 as Bine's Bridge, which is seven miles higher th.an Beeding, it may 

 readily be supposed that the chalk in this valley is depressed to a 

 very unconnnon extent. Accordingly we find that the foin- lines 

 severally laid out by Mr. Vignoics, Mr. Stephenson, Mr, Gibbs, and 

 Mr. Cmidy, nowhere rose morethan'JS feet abovehigh water mark in 

 their course through this valley. The general feat lu-es of a section 

 through this pass, taken in a straight line or a line whose curves are 

 not incompatible with railway travelling, consist of low ground 

 forming the marshes on the sides of the river, alternating with steep 

 Ijanks of clialk which flank the marshes, and which, it may be pre- 

 sumed, presented a greater resistance to the original force of water 

 than the adjoining parts of the chalk which have been swept away 

 towards the sea. 



The valley of the Adur affords the engineer many instructive op- 

 portunities of observing the conditions imdcr which slopes of chalk 

 may be expected to stand, and it may not here be out of place to 



