The Shingle Beach as a Plant Habitat. 83 
Burton Bradstock at the western extremity to Portland at the east. 
The height of its crest above high-water mark ranges from 20 to 30 
feet, whilst its width averages 500 feet. The general features of its 
structure formed the subject of a well-known paper by the late Sir 
John Coode, 1 whilst from time to time the questions of the origin 
and drift of the shingle have been the subject of considerable con¬ 
troversy, and, indeed, are still unsettled. 
Prom Burton Bradstock to Abbotsbury (6 miles) the Chesil 
fringes the mainland (PI. 4, Fig. 4); from this point to Portland the 
bank is separated from the mainland by a shallow estuary, the Fleet 
or Backwater, about eight miles long and rarely exceeding half a 
mile in width. 
Fig. 5. Sketch map of the Chesil Bank (after Bristowe and Whitaker) to 
show the relations of Bank, Mainland and Fleet. Shingle is drawn thick black. 
In effect, this portion of the Chesil Bank resembles the variety 
of shingle spit termed a Bar (cf. p 74), i.e., that type in which the 
apex of the spit comes to rest against the land—in this case the 
island of Portland (Text-fig. 5). It exhibits also many of the 
phenomena characteristic of shingle spits. Whilst it is possible 
that the Chesil Bank may in its manner of origin actually be a Bar, 
there is another view of its nature which has received increasing 
support in recent times. On this view the Chesil is regarded, 
developmentally, not as a spit, but as a fringing beach behind which 
the land has retreated in consequence of sub-aerial denudation. 
According to this theory—originally formulated by Bristowe and 
Whitaker 2 —the Fleet or Backwater has been excavated behind the 
1 Proc. Inst. Civil Engineers, Vol. XII., 1S53, p. 520. 
* Geol. Mag., Vol. VI., 1869, p. 433. 
