January, 1913. 



KNOWLEDGE. 



Figure 4. 



which growth is mainly in length ; 

 and this is followed by a more 

 or less prolonged phase of hook 

 formation, when the action of the 

 current begins to yield its domin- 

 ation to the activity of the gale. 

 Blakeney Bank illustrates in its 

 finger-like stretch of two miles the 

 formation of multiple hooks on the 

 grand scale (see Figure 6) ; and 

 here there seems to be evidence 

 of the oscillation of conditions 

 in which the current and the 

 wave have alternately triumphed. 

 The Chesil Bank, which furnishes 

 the most considerable and impos- 

 ing accumulation of shingle in the 

 British Isles, forms a problem by itself. It stretches 

 fifteen miles as a continuous strip from Burton 

 Bradstock to Portland (see Figure 3). The height of 

 its crest above high water mark ranges from twenty 

 to thirty feet, while its width averages five hundred 

 feet. The roar of a south-western gale on its pebbles 

 at the Isle 

 of Portland is 

 a sound which 

 lingers in the 

 ears of anyone 

 who has ever 

 slept, or lain 

 awake, during 

 a night there. 

 From Burton 

 Bradstock to 

 Abbotsbury (six 

 miles) the Chesil 

 Bank fringes the 



From a Photograph ly 



Figure 5 



mainland (see 

 Figure 4) ; from 

 this point to 



Portland the bank is separated from the land by a 

 shallow estuary, the Fleet, or Backwater, about 

 eight miles long, and sometimes half a mile in width. 

 As already observed the Chesil Beach might be 

 regarded possibly as a Spit or a Bar. Quite recently 



Figure 6. Inner edge of Blakeney Main Shingle Bank encroaching on the 

 " Marains," looking west. The bushes are Suacila fruticosa. 



Chesil Bank looking S.E. from a point opposite Burton Mere, 

 near Burton Bradstock. 



it has been thought to have developed not as a spit 

 but as a fringing beach behind which the land has 

 retreated in consequence of sub-aerial denudation. 

 The Fleet or Backwater would thus have been 

 excavated behind the bank. Professor Oliver 

 remarks on a peculiarity of the Chesil Bank, 



confirmatory 

 of this theory, 

 which is that the 

 bank presents 

 not a convex 

 but a concave 

 front to the sea. 

 There are many 

 other problems 

 of the shingle 

 bank, especi- 

 ally the move- 

 ments of its 

 hooks, and the 

 percolation of 

 water through 

 it — for which 

 further reference may be sought in Professor 

 Oliver's original work ; and there, too, will be 

 found an outline of the development of the 

 flora of the beach. One of the outstanding 

 mysteries of the shingle spit is its water supply and 

 the plants which are nourished 

 by it. The lower parts of 

 the spit are tenanted by plants 

 which do not need salt. Above 

 them there is a residuum of plants 

 intolerant of salt. Where do they 

 obtain the water to nourish them ? 

 Such water exists, and is indeed 

 astonishingly copious, in the 

 interstices of the shingle. In last 

 year's burning summer the upper 

 vegetation of shingle spits pros- 

 pered, and the sheep fed on it — 

 especially on the Chesil Bank. The 

 source of this water is possibly 

 to be attributed to the formation 

 of internal dew in the shingle. 



E. J. Salisbury, July, ic, 



A new hook at Blakeney Point, formed in March-April, 1911, on 

 the bank marked with an arrow in Figure 1. 



