Account of the Dymchurch Wall, Which Forms Th,E Sea

KO. 769.--(-(Account of the ~Dymchurcll Wall, whichforms the Sea Defences of ltomney Marsh.” By James Elliott, Jun., M. Inst. C.E. THEportion of Kent,called Romney Marsh, comprisesonly the eastern part of the great level : it contains an area of about 24,000 acres, and extends between the towns of Romney, Appledore, and IIythe. This tract is governed by a corporation, composed of the Lords, a Bailiff, and the Jurats: the Lords are tlle owners of the several manors,or lordships, withinthe marsh, or theirdeputies ; tlle Bailiff and Jurats are annually elected from among the residents in the marsh. No satisfactory account exists of when, or by whom, the mars11 was reclaimed from the sea ; the Romans, however, have, in popular opinion, the credit of this great work; at all events, it is evident from recent discoveries, that they occupied a considerable portion ofthe country, between Dymchurch and Romney, and there is reason for believing, that it was in an habitable state at that early period. The remainsalluded to, whichwere discovered wlrilst making some alterations in the line of the sea wall, extended over a spaceof several acres; they consisted of an ellormous mass of pottery, from the coarsest unbaked kind, to the finest Samian ware; much of it in a perfect state of preservation.. The presence at this spot, of beds of very fine white clay and layers of clean sharp sand, wouldlead to the inference, that it was thesite of an extensive manufactory of pottery, particularly as the effects of fire are evident in all directions. These remains, taken in connexion with the ancieut Roman fort at the foot of Lympne Hill, on the borders of the marsh, within a distanceof five miles, and theStone-street Road, anotherRoman work,leading from thence to Canterbury, may fairly lead to the inference, that the Romans were the originators of the work. Bnt it is not quite so clear where this work was commenced, or how it was executed. It is probable, that the seawas notabsolutely ex- cluded,by the erection of Dymcllurch Wall, butthat where the wall now stands, a natural barrier of shingle and sand was formed, in the first instance, the sea still flowing over the land at the back, and that it was gradually restrained, by the erection of cross walls, or embankments, stretching from this natural barrier up to the base of the hills. This natural barrier commenced at the chalk hills, to the west-

Downloaded by [ University College London] on [21/09/16]. Copyright © ICE Publishing, all rights reserved. DYMCHURCH WALL. 467 ward, and before the waters of the Rother discharged themselvesat Rye, formed a continuous full ” of shingle, from thence to Hythe, and also formed (prior to the extension of Dungeness Point,) nearly a straightline of coast, fromHastings to Dover; a considerable length of this ancient coast (Plate 41) may be plainly traced at the present day, extending a distance of eight, or ten miles, from the eastward of New Romney, to the westward of the town of Lydd, which was built about half a mile in advance of the first formed full.” Thatthis line was formerlykept up, acrossthe bay of R,ye Harbour, may befairly inferred, from the fact, that the old town of Winchelsea, which was destroyed by a great inundation, in the reign of Edward I. (1250 to 1287), formerly stood about the centre of this bay, and most probably on the then line of coast. There is reason to believe, that the shingle at Hythe was connected with that at Romney, on the line where Dymchurch Wall is now erected, as there are shingle banks running under and inland ofthe present wall, throughout its whole length,nearly at right angles to the line of coast, exactly in the position into which they wouldbe thrown by an adverse wind andstrong current on the end of the “ full,” while in a state of formation. The vast accumulation, of not less than two square miles of shingle, between the eastern end of the wall, and the town of Hythe, is wortl~yof atten- tive observation, as it is evident, from the position of the “ fulls,” orridges of shingle, which all lie at right angles to the line of coast, that a very strong current of water must have been passing in and out of thegreat estuary which now forms the marsh, as many of these fulls ” are carried upwards of three-quarters of a mileinland, in a continuouscurve. It is also evident,that the extensioneastward of the main ‘‘ full” was very slow, as these inland, or right-angled “fulla,” are formed close upon each other, withbut just ridge and valley sufficient to define thecourse of formation. The space now occupied by this mass of shingle formed, no doubt, the ancient haven of I-Iythe. This accumulation must have been the work of ages, and whilst it was going on, the sea was gradually raising the surface of the marsh, behind the ‘‘ full ;” it is also worthy of notice, that the land gradually falls from the line of coast, towards the hills forming the northern boundary of the marsh, and near the foot of which, are all the low lands. On the ebb of the tide, all the waters were by this natural inclination of the surface, directed to this part, thus forming what was supposed to be the river Lymene; but which was in fact only the iowest part of the great estuary, whose exit was at Hythe. This will also accountfor no traces of the ancient river being

found inRomney Marsh, nor any vestiges of Ranks, or walls to denote that there had at any time been a river, or chnnnel ill that district ; a fact which appears to have surprised Leland, who in his ‘6 Itinerary,”writing of Lympne,states ‘‘ thatwhere the river Limeneshould be, I cannottell, except it should be, thatthat cometh above Appledore, and that his course is changed, and run- neth a nearer way to the sea by the encreasing of Romney Marsh, that was sometinle a11 sea.” It may, however, be fairly presumed, that all traces of this river disappeared during the general process of silting. The followingfact may throw some light on the causeof the change, that appears to have occurred in the course of the waters from Hythe to Rye. About half-way between the haven at Hytlle and Appledore, there is a tract of land considerably higher than the other parts of the marsh, so much so, that to this day it is necessary todrain a portionof the marsh out at Ryeharbonr. The cause ofthis difference inthe general level would appearto be, that about this spot the great rush of sea entering Hythe haven would somewhatabate its fury, and as a matter of course, wonld there deposit a large portion of the silt, previously held in suspension. In the course of time a bar would be formed in the channel, which was theoutlet for the waters above Appledore. This bar eventually forcedthe waters into another channel, and then the process of silting up what was called the river Lirnene, to the general level of thesurface, was rapidand complete, until atlength even Hgthe haven itself disappeared, and now scarcely anything remainsto point out its site. Such was most probablythe state of Romney Marsh when the Romans took possession of this country, or at all events, it was fast progressing towards it; and it must have offered a strong induce- ment to that enterprising people to obtain possession of so large a tract of open country, when it is considered how sligllt would be tile labour of bringing such lands into cultivation, and that all around was an extensive forest. Presuming this opinion of the origin and state of Romney Mars11 to be correct, all the artificial works that would be necessary to shut out the sa, would be to erect walls running from the ‘6 full’’ to the hills, andevidence exists to show thatit was by such nleans the object was attained. The Rhee Wall, running nearly in a straight line from Romney to Appledore, bears strong evidence of being a Roman work; and it is, probably, at this spot that the main work for excluding the seawas performed. It isevident, that in the construction of this

Downloaded by [ University College London] on [21/09/16]. Copyright © ICE Publishing, all rights reserved. DY MCHURCH WALL. 469 work, two objects were kept in view; one to exclude the sea, the other to provide aneasy exit for the hill waters, and also a drain for the reclaimed lands ; these objects were attained by a cutting about 80feet, or 100 feet wide, running the whole length of Rhee Wall, the parallel banks of which can still be plainly traced, and it was this cutting that, in the course of time, formed the haven and port of Romney. It is further evident, that Rontney Marsh was reclaimed at once, from the fact that there is not a single internal wall of any description between Rhee Wall and Lympne, where it would appear that theeastern wall was built,although it is not so clearly defined as the other. Inthe construction of Rhee Wall comparatively little labour was required, that part next the sea, by Romney, demanding little beyond cuttingthe dyke, the natural surface of theland being higher than most other parts of the marsh ; indeed, a considerable extent of land about Romney isconsiderably above high water-mark, and has always been exempt from the “Wall Scot,” paying for the drainage only. This high land is rather a remarkable feature, as it bears strong evidence of being composed of the natural strata, the ‘‘ Hastings sand,” consisting of sand of various shades of colour, from yellow to grey, interspersed with layers ofironstone. It can betraced over a veryconsiderable space, extendingwestward to Lydd, and northward towards St. Mary’s, and probably is the remains of an island in the bay between Hythe and Fairlight. From Brenzett the marsh gradually falls towards the Ilills, and in this part considerable labour was required in the construction of the walls, which are in many places from 12 feet to 15 feet high ; this is particularlythe case towards Appledore. .This part,called

‘6 Appledore Dowles” is at the present time the lowest part of the marsh,and it can only be effectually drainedby artificial means, which have from time immemorial been used for that purpose. At what period it was necessary to resort to artificial means for preventing the inroad of the sea at Dymchurch, it is now difficult to ascertain. The earljest charter of which there is any record, is that of the 36th Hen. 111. (1252), wherein it was cited as having been governed ‘‘ time out of mind” by ancient and approved cus.. toms; and the first written laws, are those ordained by Henry de Bathonia in 1258, which have been acted on, with but trifling vari- ations, to t.he present day. It is rather remarkable, that amollg the numerous commissions granted to overlook the sea wallsin these parte, from the reign of Henry 111. to that of Richard III., not one bears any direct reference to Dymchurch Wall. TIE only one that [ 1847.1 21 Downloaded by [ University College London] on [21/09/16]. Copyright © ICE Publishing, all rights reserved. 470 WALL. DYMCIIURCK can befound bearing any indirect referenceto this work, is that of the 48th of Edward 111. ; but the commissions invariably have reference to the sea wallsbetween Romneyand Appledore, by Rhee Wall (now five miles inland), and the various walls that were erected in reclaiming Walland Marsh, beyond Rhee Wall, to the westward. This goes far to show, that but little artificial work was required at Dymchurch at that time. As the supply of shingle was cut off from this line of coast, by the extraordinary accnmulation and extension of Dungeness Point, and the shingle forming the ‘‘ full,” between Romney and Hythe, still passed on tothe eastward, in course of timethe natural full ” atDymchurch became weakened, and eventually it became evident, that something must be done to prevent the sea from breaking through and overwhelming the land. It is probable that the first measure resorted to was the erection of inland, or as they were then termed ‘‘ insett” walls, at some little distance from the“ full ” oTshingle ; these were then only intendedto prevent an overflow by an estraordinary tide, and were erected, from time to time, behind any weak part, without much regard to any general plan. As the ‘‘ Full” still continued to decrease, attention was next directed to check this shifting of the shingle, and this was the object, no doubt, of the immense stone groynes, or “ knocks,”as they were formerly called, which existed until within the last fifty years.These groynes were masses of large loose rocks,secured between timber piles, and placed at right-angles to the line of the coast ; many of them dividing at the end next the sea in the form of the letter Y. The site of many of these groynes may still be seen at low water, but far separated from the present line of wall, giving a good idea of the quantity of shingle that has been lost at this place, as there cap be no doubt that at one time they were connected with the “ full,” and formed a prominent feature in its defence. Wotwithstandingthese erections, the mass ofshingle still de- creased; the supplybeing cut off at Dungeness,and whatever escaped to the eastward, permanently lessened the mass, as it never returned ; so in course of time, the “ Full” gradually worked back to the inland walls, and occasionally exposec them to the action of the sea, duringextraordinary tides and winds; consequently the system of “ arming”with brushwood,piles, andoverlaths, was commenced. Therecan be no question, thatthe introduction of this description of work was very gradual, but it appears to have been used fromthe earliest periodof whichthere is anydirect record(the 2nd of Henry VIII.), nearlyone hundred and fifty years after the first indirect reference to the arall, in the commis- sion granted by Edward 111.

Downloaded by [ University College London] on [21/09/16]. Copyright © ICE Publishing, all rights reserved. DYMCHURCH WALL. 47 1 Thatthe quantity of brushwood required was small,may be inferredfrom the fact, that all that was employedwas grownin the marsh, the comnlon white-thorn (Cratargus oxyucantha) being solely used forthat purpose; plantations of this thorn were kept up in various partsof the marsh, under the direction of the Lords of the Level, and some remains of them still exist, but they gradually became insufficient to meet the necessity of an increase of “ arming,”and about the commencement of thelast century re- course was had to the woods on the hill, from whence the supply has since been obtained. This again goes far to show, that Dymchurch Wall is, comparatively speaking, a modern work, and it would appear, that it had never been found necessary to apply to any professional engineer for advice in maintaining the works, until the beginning of the pre- sentcentury. The whole of the works wereformerly carried on under the direction of the residents of the district, who being without the least pretension to engineering knowledge, could hardly be supposed to have been able, unassisted, to have contended with any serious difficulties. No satisfactory account can be arrived at, as to the actual quantity of artificial work executed, antecedent to the memoryof persons now living, and in many cases even this is rather vague and inde- finite ; butit appears evident, that a gradual extension ofthe 6‘ arming” had become necessary, as the wall became a more per- manent structure, and had for its object the complete exclusion of the sea. It is somewhat singular, that the commencement of the three last centurieshave been critical periods for the Level. In 1706, it appears to have been in a very precarious position ; the records of that year state, that a great part of the Level was under water, and the proprietors of the soil were called upon to come forward and assist, as the inheritance was at stake, the main burden having been always charged on the occupier. In 1803-4, the late Mr. Rennie was employed: this is the first instance on record of an engineer havingbeen employed on the Sea Defencesof Romney Marsh. Acting under his advice,the first attempt was made to reduce the works toa system, but still nothiug was used but brushwood, hop-poles, piles and overlaths, for securing theface of the wall. It is notrecorded whether Mr. Rennie re- commendedany other material for the protection of the wall, as all the papers and plans, referring to his survey of the district, were allowed tobe taken from the office in 1827, andin spite ofall attempts to recover them, theyhave unfortunately never 212

Downloaded by [ University College London] on [21/09/16]. Copyright © ICE Publishing, all rights reserved. 472 DYMCHURCH WALL. been restored. His views can ’therefore only be judged of by the result. Previously to the year 1800, the walls appear to have been very nearlyperpendicular, having only a slopeof 14 or 2 to 1 on the sea-face. This was all very well, so long as a mass of shingle lay at the foot of the wall and received all the force of the waves. As theshingle disappeared, all thatwas done was tocarry the “ arming” a little further down, still continuing the same slope,. and so on from time to time, until they had increased the face of the “ arming ” fromtwo yards to perhaps ten, or twelveyards, without any reference to the increased force of the sea, from the extra depth of water breaking against it. This was the state of the wall when Mr. Rennie was consulted, andgreat fears were entertained for thesafety of the marsh. He recommended a slopeof 6 to 1, faced with brushwood, piles and overlaths; this slope was obtained by throwing the top of the wallinland, and bringing it intosomething like a generalline. 111 making this alteration a sum of about 5 50,000 was expended in three years, whilst the average expense for many previous years had not exceeded 23,500 per annum; but even with this great outlay, only a small portion of what now forms the wall was repaired, as nearly the whole of the works carried into effect, under the direction of Mr. Rennie, were confined to the westward of Dymchurch, which is less than one-third of the entire length of the wall, and what is nowconsidered the least dangerous part, as the whole of this length is in much shallower water than that to the eastward, which fortunately at that time was secured by a mass of shingle at the foot of the wall, and required but littleattention. It was not until1825 that an attempt was madeto introduce any other material than wood, for securing the heof the wall. About that time it was proposed to try the effect of ‘‘ Kentish rag- stone,” brought from the hills at Hythe ; this has gradually super- sededthe wood, until, atthe present time, no “ faggotarming” remains on the whole length of wall. For someyears after the introduction of the “ Kentish rag-stone,” it was only used by way of experiment,and then not under the most favourable cigcum- stances,as it was laidby common labourerstotally unacquainted withsuch work, under very indifferent instructors, and even pre- judiced against its introduction, in which feeling the Lords of the Level participated to some extent, as they differed in opiniou, as to what would be the ultimate result. In consequence of this feeling, the wall was, after some time, againpermitted to fall into abad state;the whole extent being a seriesof experiments of various

Downloaded by [ University College London] on [21/09/16]. Copyright © ICE Publishing, all rights reserved. DYMCHURCII WALL. 473 slopesand modes of construction,.and many breaches remained unrepairedfrom year to year, until it should be decided whether they were to be repaired permanently with wood, or stone. In the early part of the year 1837, Mr. Elliot, senior, and the Author, were employed to make a survey and report, advising the course to be pursued, for putting the wall in a more secure state. After a careful survey? and for manyweeks devoting great attention to the action of the sea, it was decided, that stone was preferable to wood ; the chief question was then to ascertain the proper slope, inorder, if possible, to preventthose extensive breaches that SO constantly occurred. TheReport recommended, that the general line of thewall should be modified, and rendered as straight as possible, adopting a slope of seven to one for the main part of the wall, rising suddenly atthe top,with a curveof 7 feetradius (Plate 42); thatthe workshould be further secured, about medium high-water mark (where it was ascertained the greatest damage always occurred), by thee rows ofsheet piling 6 feetlong, using deal-ends 3 inches thickfor the purpose; these were to be driven parallel with the line of wall, the great object being to prevent under-draft, on the receding of the waves, bywhich greater damage was generally cansed, than by the in-flow of the wave, and, at the same time, to prevent the spreading of thebreaches, which from the nature of the work, no amount of care will, however, entirely prevent. If the views embodied in this Report had been effectuaIIy carried into operation,a heavy expensewould have been entailed on the occupiersof the land; it was therefore deemed advisable to obtain farther advice, before entering upon so extensive an undertaking, and,in consequence of this decision, BIr. Walker was consulted. His survey was made in June and July of the year 1837, and the general views 'contained in his Report, did not differ in principle from those embodied in the Author's previous Report. Mr. Walker considered that a slope of 6 to 1 would be sufficient ; but, at the same time, he thought it desirable to obtaina better sub- stratum than clay, and therefore recommended a bed of conerete of lime, sand, and fine shingle, or stones, to be placed under the stone facing,or, rather, the stones of thepitching were to be bedded intothis concrete, whichwas also to partially fill theinterstices ofthe pitching. It appears also, thatMr. Walker perceived the necessity of a further security to the centre of the work, and for

' this reason, he recommended deepbonding courses of thesame stone, to be placed nearly in the same position as the sheet piling,

Downloaded by [ University College London] on [21/09/16]. Copyright © ICE Publishing, all rights reserved. 474 DYNCHURCH WALL. aud, at the same time, that greater care should be observed in the preparation of the st.one. As the Lords of the Level were still undecided, as to which plan should be adopted, another experiment was determined on, and the Author was directed to complete a length, according to the plan recommended by his Father and himself, whilst Mr. Finn, the then Expenditor, was instructedto superintend the construction of a length, according to his views of Mr. Walker’s plan. Inthe followingyear, the wholework was entrustedto the Author,and he was left entirely at libertyto carry out the plan which he considered the best, the Lords of the Level pledging themselves not to interfere, or to give orders, except in furtherance of the plans decided upon ; the whole responsibility thus devolved on him. He had the advantage of being able to examine the merits ofthe plans tried during the previous year, two lengths having been completedaccording to theorder of July 1837. After ma- ture consideration, he decided, in the spring of 1839, to adopt very nearly the same form of structure as he had, in concert with his Father, recommended in 1837, which had stood well through two winters ; butto modify indetail what he found from experience to beadvantageous, and, at thesame time, toadopt as muchof Mr. Walker’s plan as might be desirable. The slopes previouslyrecommended were 7 to 1 and 6 to 1 ; even the flattest of these did not answer quite so well as had been anticipated,the chief desideratum being, that all the interstices should be kept full of the sand and fine particles of shingle, which wereconstantly travelling over its surface. It was, however, found that to effect this the face of the wall must be still flatter. The entire refacing of the whole length of the wall having been decided on, the operation was commenced at the eastern end, which, from the exposure, was the most likely to be injured. At the same time, an entirely new line was laid down for the mall, approaching, in some places, nearer to the sea, and at others, bearingmore inland, so as to obtain, as nearly as circumstances would admit, one general curve. It was still determined to depend, as before, on the sheet piling, which was found to answer every expectation, there being no signy of the defects which had been contemplated ; but, at the same time, somewhat changing the positions; one principal object in doing this being to obtain a flatter slope, without increasing the expense. It had always been found necessary to carry the foot of the wall down to a certain depth, to insure its being always covered, as -rei1

as supported by the sand ; the surface of whichwas constantly vary- ing, according to the prevailing wind and the force of the sea. In order to avoid this extra slope, it was proposed to place one row of sheet piling at the foot of the work, as this would not only enable thefoot to be thoroughly secured, but would, atthe same time, permit the slope to start from the highest level, usually assumed by the sand, without endangering the safety of the whole work :- thus obtaining a flatterface, without increasing the breadth. The slope was constructed on an average of 8 to 1, to high-water me- diumspring tides, increasinggradually from that point until it terminated in a curve of 7 feet radius (Plate 42). Above medium high-water, the whole of the stones were laid in a bed of concrete of six parts of fine beach and sand, to one :part of lime; lower down the concrete was perfectly useless, as where it was covered at every tide it did not set with sufficient rapidity to wit,hstand the action of the sea. Various-sized stones were used for different parts ofthe slope: those at the foot were 12 inches deep, inthe next division they were 15 inches deep, and in the centre between the rows of sheet piling, where the greatest wear and tear always took place, they were 18 inches deep : after this they diminished again to 15 inchesand 12 inches, andin the remaining portion, where the concrete was used, they were only from 6 inches to 9 inches in depth ; the concrete enabling a portion of small stones to be used with equal security, and thus diminishing the general expense. Such is a brief outline of the plan commenced in 1839, and which has been steadily persevered in, up to the present time, to the entire satisfaction of the Lordsof the Level, and the occupiersof the land, and although the Author has devoted almost exclusive attentiou to the work, for nearly ten years, and has watched the action of the sea under all circumstances, he has not found it necessary to make any considerable alteration in the original system. When the Authorfirst took charge of theworks, in 1838, nothing could be in a worse state, and the annual expenses were rapidly increasing. The whole length of the wall isnow in a perfectstate of repair, and the expenses are reduced from &XO,OOO to S4,OOO per annum, with every reasonable probability of this amount being still further reduced, as above two-thirds of the length of the wall have been permanentlyconstructed; and judging from the dura- bility of that part now completed, it will be many years before it mill requireany considerable repair; the parts above and be!ow the extremes of high and low water will not, it is expected, demand any repair for many years, thus affording the best evidence that the plan adopted is sufficient for the purpose.

The average costof the work, as it is now executed, after the face of the earth is prepared and put into proper form, is about five shil- lings and sixpence per superficial yard, the various items being as follows :- S. d. Stone in the quarrythe Stone in . . S . , . . 0 7 Excavating and delivery (5 miles) ....3 3 Preparingand laying (includingthe driving thesheet piles),and preparing the concrete ....1 3 Sheet piling ...... o 4 Lime ...... 0 1 -56 The courseof the mass of shingle, on that part of the coast, appears to be invariably to the eastward, which is the direction of the flood tide, and of the prevailing wind. On the accompanying Map of the Marshes, published in 1617, (Plate 41,) the extent of the alterations caused by the shifting of theshingle is shown ; a considerableamount has been lost, both east and westof Dym- church, since the date of that survey, while Dungeness Point has been extended considerably within the same time. Under what circumstances and at what period that extraordinary formationtook place, ia a difficult problem to solve. It is very evident, that at some period the line ofcoast was inland of the town of Lydd, which is now upwards of three miles from the sea. It is worthy of remark, that the timbers, &C., from any wreck 011 the west coast, are generally carried round and landed on the east of Dungelless Point, proving that a very considerable eddy exists in that direction ; the impetus given by the current in the main channel being evidently lost, and the force, or rather the loss of force in this eddy, causes the accumulation of shingle at, and round, the point to the eastward. No certain record has ever been kept of the increase of the coast line; but from the best existing data, it appears to be about two yards annually, and allowing the accumula- tionto have been rather more rapid at first,say threeyards per annum, a period of about nineteen hundred years will have elapsed, since the sea first left the original “ Full” at Lydd. This would be about the time of the first landing of the Romans in this country, and it is not improbable that some of their works at the then Port of New Romneyformed the nucleus of whatis now Dungeness Point. The constant decrease of shingle in the neighbourhood of Dym- church Wall, the supply to which had been cut off at Dungeness, has been already alluded to.

From 1766 to 1826, a period of sixty years, a very large sum was expended in the erection of timber jetties, or groynes, to prevent this gradual shifting to the eastward, and as long as there was a quantity to the westward, towards Romney, to keep up a supply, there can be no doubt, that they would have materially assisted in the object, if they had been placed with any system: it may, however, bedoubted, whether the benefit obtained was equivalentto the expense incurred ; and on the whole it may generally be con- cluded,that groynes are practically useless,unless insitnations where a very considerable quantity of shingle is passing, and it is desirable to check it at any particular point. At Dymchurch they do as much injury to the e‘ast, as they confer benefit to the west, and this is snre to occur, where the supply of shingle is at all de- ficient. The prevailing wind is from the south, and at that time a very heavy sea rollsin at Dymchurch ; but it isthe south-eastwind thatdoes the greatest damage, being deadon-shore. Frequently during the winter it causes a tremendous sea on the face of the work, and occasionally the surf from an extensive wave will overtop the new work, although it is 12 feet above an ordinary spring tide. The severest storm, during the last ten years, laid the shingle to the east and west of the wall, at an angle of about 12 to 1, and it may be presulued, that if the artificial slope was increased to that inclination, but littleeffect would be produced, even by the heaviest seas; at present, with a slope of 8 to I, the waves wash out every particle of sand and shingle from the intersticesof the stones, which become loosened, andhence extensive breaches frequently occur. On the other hand, a north-west, or off-shore wind causes an accumulation of sand and shingle at the foot andon the work, rendering it for the time perfectly secure, and if continued for any considerable time, throwing the natural ‘‘ Full” back again, and laying it frequently at a slope of 1 in 5. Any wind from the north-east to the south-west, if of long duration from any one point, is found to be equally injurious, the effect being to remove the detached quanti- ties ofshingle lying on the wall,and to accumulate the maisat someextreme point, while the other part is completely denuded, down to the earth ; and, in many instances, it has become necessary to ‘‘ arm,” or pave,” a length thus temporarily exposed, for fear of greaterdamage, before a shift of wind occurs tocarry the shingle back again. Notwithstanding the loss of the supply of shingle to this coast, from the accumulation at Dungeness, there can be no doubt, that the extension of this point is a great protection to the Dymchurch

Wall ; preventing, to a great extent, the heavy sea from the south- westfrom breaking on the wall, as it does onthe shore at the western side of the point ; the roughest sea at Dymchurch, being smooth water in comparison to that to tilewestward. The paper is illustrated by i~ map of the marshes, (Plate 41,) published in 1617, which conveys an idea of the ancient coast-line, and the alterations at Dungeness, and on the site ofthe Dymchurch Wall ; also by a plan and cross sections of the wall, (Plate 42,) copiedfrom those taken by Mr. J. B. Redman, in 1837, and sections of the present wall, as executed by the Author.

Captain D. O’BRIENsaid, that having been from 1830 to 1838, jointly with another Oficer of the Royal Staff Corps, in engineering charge of theMilitary Canal, which bounded the northern and western sides of Romney Marsh, he had constant opportunities of witnessing the action of the sea upon the coast ; and as during that period his head-quarters were at Hythe, which was wt more than threemiles distant from Dymchurch Wall, hisattention was naturally directed to its construction. Romney Marsh, like almost every other flat bordering the sea, was, heconceived, created by a river. TheRother, in former times, debouched within about two miles of Hythe, under Lympne, and its junction with the sea formed the ‘‘ Portus Li.manus” of the Romans. In the course of years, the siIt brought down by its current, formed a bar at its mouth, and a delta was created ; the riverbecame choked u.p, andits waters sought another outlet. Instead of skirtingthe high grounds, and pursuing an easterly direction, which appeared to have heen the original course of the river,it ran southwards, depositing its silt, meeting the tides, encounteringthe run of the shingle along the shore, and OCCB- sionally forming bars, which pounded back the waters, and forced them into other channels. One of its old beds might be distinctly traced through the heart of the Marsh, in the direction of New Romney,though it was higherthan the ordinary level of the adjacent fields. It was not accurately known when this bed became choked up, butit wassaid tohave been in existence in the reign of Edward 111. ; ithad also been statedin the reign of Elizabeth, that an applicant had received a grant of the dry bed of the river, in the reign of Stephen, about the year 1.150. At present the river Rother joined the Brede at Rye, and flowed intothe sea, atabout twenty miles fromits original outfall.

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