The failure of groins, erected with pile and plank, appear to arise from their being placed in a wrong situation, from their not extending far enough into the sea, from the piles not being driven sufficiently into the beach, and from their sudden elevation, present an abrupt surface for the tidal wave to play upon, which during heavy gales of wind upon spring tides, cannot withstand its powerful effect, should the materials lying adjacent to or between them be removed. Therefore they can only be available where the interstices are completely filled with sea beach materials, and their durability must depend upon the latter cause. CHAPTER VI. THE RESTORATIVE POWER OF THE GERMAN OCEAN PROVED IN CERTAIN LOCALITIES.—ASSISTANCE GIVEN TO IT FROM THE STRANDING OF A VESSEL AT PURBECK, AND ON THIS COAST AT HASBOROUGH.—HILLS OF BLOWN SAND OR DUNES CONSIDERED—EXAMPLES OF THEIR STABILITY GIVEN AT WELLS, CLEY, &C., AND OF THEIR INSTABILITY AT ECCLES, PALLING, &C.—SEA-BREACH COMMISSIONERS APPOINTED.—THE ENGAGEMENT AND OPINIONS OF AN EMINENT ENGINEER IN 1804.—CONCLUDING REMARKS. EXAMPLES of Nature endeavouring to combat with herself are shown from the immense quantity of sand, shingle, &c., brought from low to high water mark, during the summer months, and should easterly winds prevail, the sand is removed towards the cliffs, and accumulates in some situations more than in others. Thus at Walcot, {47} a deposition of sea beach materials commenced in 1839, and gradually augmented from six to eight feet in depth, within a distance of one mile and a half, and in a space comprising a few yards, it attained a perpendicularity above the cliffs, extending to high water mark, and the tidal wave, even in a northerly wind, ebbed and flowed without disturbing its surface, from the above period to November, 1843. A gale of wind then ensued from the north-west, upon a neap tide, which removed the greater part of the mound of sand, and a subsequent gale, upon a spring tide, in February, 1844, swept away the remainder. A similar instance of accumulation was observed to have taken place on the Essex coast, commencing about the same period, and extended a distance of seven miles, which appeared in December, 1843, likely to remain. {48a} The flat shores at Wells {48b} are considerably elevated above the depths of the ocean, into which they probably terminate in a gradual descent. The stranding of three large vessels off Winterton {48c} and Horsey, {48d} years ago, have possibly prevented its encroachments in these places.