1S:',0.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



•200 



record the result of some observations made to ascertain the practi- 

 cability of inducing vegetation on steep slopes of this material. In 

 favour of the practice of constructing chalk excavations with slopes 

 approaching to vertical, it has been urged that the danger of slips 

 would be very much lessened, if not entirely removed, were it pos- 

 sible to cover them with any kind of grass, which would have the 

 cll'ect of holding and tying "together the minute fractured parts occu- 

 pying the face of the slope. This notion is plausible, but would 

 scarcely seem to be supported by the state of natural slopes now ex- 

 isting, luid which, therefore, present an unexceptionable ground work 

 for JLulging on the subject. The following are the observations 

 before alluded to. : — 



The old Shoreham windmill stands on a suunnit abont 180 feet 

 above the road to Brighton. The face of the chalk at this place is 

 very steep and the vegetation is partial ; grass, however, was grow- 

 ing undisturbed at an inclination of l^lj horizontal to 1 perpendicular. 

 On a slope of It to 1, vegetation is partial, and in many places the 

 soil has I)cen carried down by the rain, which has fonned small 

 gulleys or ravines down the slope. The summit at this part of the 

 chalk district is not more than 1.50 yards from the base of the hill, 

 conseijuently neither the removal of tlie soil from the face of the 

 slope, the formation of the small gulleys, nor the con.seqnent barren- 

 ness exhibited at this place, can be allributed to an extraordinary 

 extent of surface drainage washing over the slope. On an inclina- 

 tion of l-fb to 1, slight patches of vegetation appear, but the grass is 

 very stunted and thinly scattered; while on 'a slope of I to 1, no 

 trace of vegelable growth could be found. The soil covering the 

 chalk is of a light clayey nature, and varies from 5 to 8 inches in 

 depth. 



Higher np the Valley of the Adnr, and nearer to Becding, the 

 face of the liills rising from the valley at a slope of three to one is 

 extensively covered with timber. Ash and elms thrive well here, and 

 the underwood is sti'oug and healthy, consisting chiefly of white and 

 black thorn, brambles, elder, and ivy, accompanied by nettles, 

 thistles, and sti'ong coarse grass. The chalk in this district is of a 

 rubbly description, full of veins, cracks, and tissures; it is, however, 

 strong and heavy, stands well in an upright face.and contains numer- 

 ous Hints. 



As an example of the natural slope of loose chalk in embankments 

 I may mention thai, at a considerable excavation near Beeding the 

 rubljish or refuse clialk wheeled into spoil, and teamed over head lo 

 a depth of fifteen or eighteen feet assumes an inclination of \-{\, 

 hoi'izonlal lo 1 perpendicular. On this slope, which has no covering 

 of soil, and contains no mixture of mould, there are sliglit traces of 

 vegetation ; it is, however, very coarse and unhealthy in its growth, 

 consisting of a dry brown coloured description of grass, very short 

 and mixed with moss. The chalk of the excavation, from which 

 this spoil bank was made, has been worked lo a great extent for the 

 purpose of being burnt into lime, the rpialily of which is excellent. 

 The greatest depth of this excavation is not less tnan ICO feet, with 

 a face which is nearly upright, and which stands well, allhough the 

 chalk is l)y no mcaus so lirm ami compact as in some oilier parts of 

 the range. The fissures are numerous in this pit, and parallel veins 

 of Hint traverse it nearly horizonlally at unequal distances from each 

 other, varying from .'! to / feet. The upper |iart of the (jnarry, con- 

 sisting of clialk marl and chalk nmch broken and very tender, stands 

 well at (> inches horizontal to 1 foot perpendicular. 



The Saddlescondje gap is the next in order [U'oceediug eastward ; 

 and in this place, following the lowest ground in the valley, the chalk 

 summit does not exceed 3S0 feet above high watermark. It was 

 found, however, from levels taken through this gap, that a line enler- 

 ing the chalk range boldly at one of the highest pcjints of the range, 

 namely, at ihe Devil's Dyke, a lillle v,est of Saddli-scombe, encouu- 

 lered less of diflicidly :md heavy work than a line Ihrough the gap. 

 This result became evident on discovering that in cither case a 

 tunnel would be necessary, and that the ground beyond Saddlcscombe 

 gap is not so much diqiressed as two valleys or bolloms leading from 

 the south side of the Dyke. It was therefore decided bv Mr. (iibbs, 

 who surveyed Ihe country in this direction, to adopt Ihe Dyke line 

 passing on lo Brighton, to the east of Hangh-ton, through fioldstoue 

 i;,,;;o;ii. The summil of the chalk range at the Dyke is (140 feet 

 above high water, and Ihe summit at the railway was lo be 141 feet, 

 at a point about a mile beyond, or south of, Ihe highest ground inter- 

 .socted by the line. The gaudt brick earth at this jilace extends as 

 'far south as the village of Volking, rising to a height of 190 feet 

 above high water mark, and the fire-stone reeling on Ihe gault is 

 '21(1 feel above the same level. 



The next pass in the chalk range, namrly llie (!Iaylon, is of con- 

 siderable imporlance, as the line of Brighton railway sanctioned by 

 Parliament intersects the South Downs at Ibis place. The summit 

 of Clayton Hill, under which the line passes, is -KO feet above high 



water mark, and the smnrait of the railway itself m the chalk district 

 is 212 feet above the same level. The fire-stone is either very incon- 

 siderable in depth or is entirely absent at Clayton, and the junction 

 of the gault with the chalk takes place at a point opposite Clayton 

 church, abont 24.5 feet above high-water mark. A boring made in 

 the parish of Piecombe, on the north side of the chalk summil, en- 

 tered the chalk at two feet below the surface, and passed through 

 solid chalk for 55 feet when it was discontinued. Also a boring on 

 the south side and in the same parish, entered the chalk after jiass- 

 ino- through 9 feet of chalk wash, and was continued through 20 

 feet of clialk, the same stratification existing for a con,^iderable 

 depth below. In the chalk qunrry at Clayton Hill, there is a con- 

 siderable quantity of debris at the bottom, and the average slope of 

 the face is l to 1, although it presents surfaces varying from the 

 perpendicular to a slope of 1 lo 1. The chalk cutting on the turn- 

 pike-road over Clayton Hill is 45 feet deep, with slopes of I to I. 

 A chalk nit close to'the road, an<l opposite Pangdean farm, is from 

 .•?5 to 40" feet deep, and the chalk here, although it does not stand 

 well, preserves a steeper slope than the Clayton quarry already 

 mentioned. ■,■ , ^ 



The chalk of Clayton and the neighbourhood is exceedingly dry • 

 and hard, but much shattered. The lissures seem to have rent the 

 face of the chalk into a series of long-shaped pyramids, with Ihe 

 apex uppermost, and would appear lo have been caused by Ihe same 

 upheaving force which has so extensively operated on the whole 

 chalk stratification of this country. 



As connected with the subject of the South Down chalk range, 

 I may briefly notice the pass of the proposed south-eastern Brighton 

 Railway, this line was inlcnded to enter the chalk range at a 

 iioint called Mount Harry, and to proceed by Falmer to Brighton, 

 with a summit of K12 feet"above high water. Not having seen this 

 part of the range, I am unable to say anything from personal olwei'- 

 vation as to the nature of the chalk. It appears, however, from the 

 evidence of Ihe witnesses called in support of the line, to be not 

 unlike that of Clayton. -^^ 



Having now exhausted my stdck of information relative to the 

 South Downs, I purpose to'mtike a few remarks on the chalk of 

 Kent, which may be said lo comprise the south-eastern arm of the 

 London chalk formation. An extensive chalk cliff is exposed along 

 the coast from Folkstone away to Dover and the south Foreland, m 

 the course of which arc many interesting and well-known ponits 

 The celebrated Shakspere's cliff, from which a very extensive fall 

 has lately taken place, was a very bold projection with a face nearly 

 vertical to a height of about (It) feet above the beach. While beyond 

 this heifhl, the slope was nearly ^ to 1. The flints are almost en- 

 tirely wanting in the chalk of Shakspere's cliff, the upper mass of 

 the clifTappearingtobccomposedof hard nodules of chalk, imbedded 

 in a matrix of liner and whiter chalk, which serves to cement 

 them tor'-ether, thus forming a very close and compact substance. 

 In the npper part of this i-halk there is little or no stratification 

 visible, there bring no partings, as in the grey chalk. The lower 

 stratum of the clilf consists of grey rock chalk. Where fissures 

 appear on Ihe face of the cliff, they are almost invariably m the 

 jiyramidal form, already mentioned in describing the chalk of 

 Clayton. 



It is well known that the South Eastern Railway passes along 

 the edge of Ihe cliff^i, from Folkstonc to Dover, by means of gal- 

 leries and archways ; a mode of execution wdiich seems to be 

 unrivalled for cheapness and fticilily of execution. The works on 

 this part of th- line have been so well descrilicd in some periodicals 

 of the day, that it will be unnecessary for me to do more than allude 

 to them. 



Numerous excavations in the chalk may bo seen around Dover, 

 a few of which it may be inleresling to notice. A liltle above 

 ArchclifF Fort there are 5 caves dug into the chalk, the roofs and 

 sides of wdiich appear to stand well wilhout steining, except that the 

 roofs have slightly scaled away up to Ihe first course of flints. 

 These caves arc about 18 feet high by 20 feet wide. An open cul- 

 ling in this place, about 45 fe<'t in dejitli, stands nearly vertical and 

 pri'sents numerous layers or bands of Hint running parallel io ciich 

 other about 4 feet apart, lender the castle chtls on the east side 

 of Ihe town is a well, sunk by a builder, where it was necessary to 

 stein Ihe sides, as the chalk was loo faulty to stand without this 

 protection; and I believe I am right in saying that the chalk is 

 nowhere standing in any of the mililary works around the town, 

 without a facing of brickwork or of turf strongly picketed. Some 

 very large falls of chalk, probably not less f'han a 100,000 Ions, 

 have at various times come down on Ihe east side of Dover. 



The Soiilh Foreland is a very remarkable face of challc, wliicli 

 apjieavs at a distance to be nearly verlical, but on approaching more 

 closely is found to slope about .^ "to t, Tlie heighl.is about -'WO IVi-i, 



