DOWNS. 



gri: 



raWy capable uf encroaching. But UMT* re limiu to this rewstanoe of 

 the waves, which, with xiiue related phenomena of coast-action, we 



Profeaior Phillii-, in hi* ' Memoirs ' of hU uncle. Dr. William Smith 

 [riiaurs, Jons, and Surra, WILLIAM, in HUM;. l>iv.], hu nkeu-li.il in 

 the following comprehensive manner, the philosophy of the N..ri..lk 

 sand dune*, and their relation to the changes of the oout-line. 



" Along all thit coast (from near lUpi-Uburgh to Wintorton) the MS* 

 might enter. And spread in broad and winding sheets over 4U,000 acmi 

 of Und, but fur natural barrier of aand-hilla. thruwn up into a narrow 

 irregular ridge by the a. ti.. of the ea and the wind, ami fixed by the 

 growth of the ' marram,' ur A mtdo armaria. The set uf tide along this 

 coast u from the N.\V.. and this being the line of the mudcliffs and 

 und-hilU, the whole of the sea-barrier thus described is raked by the 

 currrnU, and the materials of which it u composed are perpetually 

 drifted to the S.E., to augment the n*~ of sand-bank* about Yarmouth 

 Haven. The waiting of the din* to the north supplies the u. 

 for the aggregation ami renewal of the sand-hills, or dunes, an>l tlio 

 whole coast U in motion ; so long, however, as the sand hills maintain 

 continuous unbroken line, they offer an effectual though variable 

 barrier to the sea ; what they have of this continuity and integrity is 

 owing to the growth uf the valuable plant already named, for its roots 

 spread amongst and bind together the sand, and its ' bents ' (stalks) 

 check the devastating action of the wind. I'laccil thus in mutable 

 equilibrium, the state of the sand-hills at any moment expresses the 

 balance of the integral effects of the sea-wind and vegetation, and from 

 time to time this balance is unfavourable to the safety of the inland 

 country ; for the wind often conquers the marram, by heaping up sand 

 more abundantly where this plant grows the best; inequalities are 

 thus occasioned; tempests succeed; the relatively depressed parts of the 

 sandy chain yield to the wind, receive the spray, and admit unusually 

 elevated waves of the sea. ' Gaps ' or ' breaches ' (fearful name !) are 

 thus generated ; the ocean, swelled by north-west winds, rushes in ; 

 the internal rivers are choked by the simultaneous flooding of the Yare 

 with salt water ; the marshes are drowned, and years pass before the 

 soil recovers its natural state." 



The manner in which Dr. Smith succeeded in conquering this fearful 

 state of things, as it existed in 1801, when the breaches in the line of 

 Band-hills amounted altogether to one mile in length, by imitating 

 the natural embankments thrown up by the sea on the same shore, 

 though most important as an operation of engineering, is foreign to 

 our present subject, regarded as one of science. It is described in 

 tin- Memoirs just cited, pp. 50-54. 



Of the two alternating processes described by Professor Phillips, 

 Sir C. Lyell, from his own observations and those of Mr. It. C. Taylor, 

 has related some facts which are particular instances ; of which those 

 consisting in the restraint by the sand-dunes of the incursions of the 

 ocean, have been already stated above ; while the following show some 

 additional consequences of the submersion of the barrier they form, 

 and also in what manner the production of dunes is carried on in some 

 localities of the same coast, simultaneously with the encroachment of 

 the sea upon the land, of which other examples will be given. 



The ancient villages of Shipden, Wimpwell, and Eccles (already men- 

 tioned) have disappeared ; several manors and large portions of neigh- 

 bouring parishes having, piece after piece, been swallowed up ; nor has 

 there been any intermission, from time immemorial, in the ravages of 

 the sea along a line of coast twenty miles in length, in which these 

 places stood. When Sir C. Lyell visited Eccles in 1839, the sea was 

 fast encroaching on the sand-hills, and had laid open on the beach the 

 foundations of a house, the upper ]rt of which bad evidently been 

 pulled down before it had been buried under the sand. There are 

 records of nine breaches, from 20 to 120 yards wide, having been made 

 through the dunes between Eccles and Wiiitcrton noticed above, by 

 which immense damage was done to the low grounds in the interior. 

 An inland cliff, about a mile long, at Winterton, shows clearly that at that 



Ct the lea must have penetrated formerly farther than at present, 

 when the sufficiency of the meals and dunes securely to protect 

 the harbours of Cley and Wells, and others, is affirmed to be dependent 

 on " the present set of the tides," and is cited as " affording a clear 

 proof that it U not the strength of the material at particular points 

 that determines whether the sea shall bo progressive or stationary, but 

 the general contour of the coast," we conceive that the resisting agency 

 of the object* and process funning the particular subjects 

 article, is greatly underrated ; while wo are precluded from admitting 

 the conclusion to be altogether true, even with respect to secular 

 periods, by the fact of that secular change in the contour of coast- 

 lines which is constantly in program, and which Sir C. Lyell has 

 himself evinced to play so important a part in historical physical 



Mr. K. C. Taylor has also described the dunes of South Wales, and 

 some attendant phenomena (' Phil. Mag.,' 2nd aeries, vol. i. p. 427). The 

 tide* on thu coast attain a great elevation. The marshes of Penibrey 

 in Caennorthetuhire have four or five concentric ridges of sand-hills, 

 forming as perfect and permanent lrricrs against the sea as the art of 

 man could execut nth O f the river Ogniore, in Glamorgan- 



shire, presented in 1 82T a singular appearance of desolation, through 

 the agency of the wind ami sand. Its ancient clnnncl was filled up 

 for two miloB, house* were rendered uninhabitable, and sand-hills were 



raised to the height of nearly 150 feet " The mountains which bound 

 the harbour," Mr. Taylor observed at that time, "will 'check the 

 advance of this Band-flood into the interior, otherwise it threatens to 

 overwhelm all the Iambi which adjoin it ; while the squalls of wind, 

 rushing down the steep valleys, occasion eddies, which deposit the Band 

 at an elevation apparently far beyond the reach of such an irresistible 

 enemy." 



Much information respecting the sand-dunes of Cornwall, their 

 encroachment on the land, and its counteraction by the use l the 

 Arntulo umarin, will be found in the 'Parochial History* of that 

 county by the late Mr. I uw. , (ill) and in the late Messrs. 



Lyaons'a ' Magna Britannia.' 



M. Elie de Beaumont [in his 'Geologic lY.ti.iii.-. 1 ,.. jis] has 

 suggested that sand-dunes in Holland and other countries may serve as 

 natural chronometers, by which the date of the existing 

 may be ascertained. The Bands, he says, are continually blow n 



torce of the winds, and by observing the rate of th. 

 may calculate the period when the movement commenced." > 

 Sir C. Lyell, whose ' Principles ' we are again citing, observe- 

 the example just given [that of Eccles] will satisfy every geologist that 

 we cannot ascertain the starting |>oint of dunes, all coasts being liable 

 to waste, and the shores of the Low Countries in particular being not 

 only ex]x*od to inroads of the sea, but, as M. de Beaumont himself has 

 well ~l.o... M. having, even ill historical times undergone a change of 

 lc\ .-!. The dunes may indeed, in some cases, be mode use of as chro- 

 nometers, to enable us to assign a minimum of antiquity to existing 

 coast-lines ; but this test must be applied with great caution, so 

 variable is the rate at which sands may advance into the interior." 



Dr. Bono has pointed to sandy sea-beaches as being the only forma- 

 tions now in progress, which are similar to deserts. [DESERTS.] If the 

 latter have been produced by the gradual .extension of the I. 

 we may probably conclude that the permanent accumulation . .1 

 HOIK! was effected by the continual successive formation uf dunes. 

 In all past ages of the earth's physical history, as at the present 

 era, they must have been formed wherever there was sea, together 

 with rocks, the disintegration of which would afford the requisite 

 material, if the form of coast-line, ami the nature of its vegetable pr<> 

 dilutions, and the prevalent direction of the winds were also favour- 

 able. And accordingly, sandstones of almost every geological age 

 might be referred to containing, vestiges of organic matter, lineally 

 disposed, which may have resulted from their consolidation. These 

 are more evident, however, in the later secondary and in the tertiary 

 strata than in sandstones of great comparative antiquity; as might 

 naturally be expected, from the longer exposure of the latter to rneto- 

 murphic action, and the gradual obliteration of organic impress!- 

 the various processes of alteration in rocks, the operation of which is 

 permitted by the lapse of tiuie. 



DUNG. [MANDBE.] 



DUODECIMALS, a term applied to an arithmetical method of 

 ascertaining the number of square feet and square inches in a rectangu- 

 lar space whose sides are given in feet and inches. For instance, to 

 find the contents of 6 feet 7 inches by 2 feet 5 inches, proceed as 

 follows : 



Feet. Inches. 



18 



11 



15 



10 



11 



In the answer, 15 means 15 square feet; 10 means 10 strips <>i ..,,. 

 foot by one inch, or 10-twelfths of a square foot; 11 means 11 square 

 inches, or ll-144ths of a square foot. This result is obtained an 

 follows : 



2 feet by 6 feet gives 12 square feet 



2 feet by 7 inches gi. 1 foot, 2-twelfil>-, 



or 14-12ths of a square foot. 



(i feet by .". in 



or 80-12tliH <>{ IL square 

 7 inches by ."i inches gi'. 



35 square inches. 



13 square feet, 2-twelftli-. 

 2 square feet, 6-twelftli;-, 



2-12ths, 1 1 



2 square feet, 8-12ths. 11 ><]. in. 

 The following instances ore perfectly similar : 



Feet. laches. Feet. Indict. 



11 :; 4 



12 7 88 



26 

 1 



28 



Ill'I'LKX (jl'KUK'LA (double i|iien-lc or complaint), a process in 

 ecclesiastical causes, in the nature of an appeal from the ordinary to 

 his next immediate superior, aa from a bishop to an archbishop, or 



