26 
VI.—SPARTINA AND COAST EROSION.* 
Ipa M. Rorer. 
An experiment is being tried in North Somerset to fight 
against the constant erosion of the coast line in the Bristol 
Channel where the conditions render it entirely different from 
what has been undertaken hitherto in other parts. 
Here the spring tides rise regularly to 36 ft., and deposit on 
each occasion a considerable amount of mud right up to the limit 
of high water, but, on the other hand, scour away equally large 
quantities when the waves beat on the coast under the pressure of 
winter gales. 
The Bristol Channel is full of long stretches of mud flats with 
deep water channels running amongst them. As the tides ebb 
and flow the edges of these flats are continually changed, and 
this apphes equally to the long slopes of mud which are exposed 
at low water on the actual shore of the Channel. When these 
shore flats become lowered by the removal of their surface, the 
up-rushing tides, moving at times at five knots an hour over the 
round, reach with increased force the earth-banks, which stand 
across the Channel between Cardiff and Weston-super-Mare, but 
in other parts of the same stretch the destruction has been 
mark. In this way they prevented specially high tides in com- 
bination with strong gales from washing away the surface of the 
ourse of yea 
both higher up the Severn and lower down as far as Bridgwater, 
at those parts where such sea-banks could give protection to the 
This system of guarding the land answered very well, although 
a certain amount of ground between the sea-bank and high-water 
_ mark was being constantly eaten away by exceptionally heavy 
Gard. Chron., ser. 3, xliii. (1908), p. 33 i 
oe Sey: (i914), > 76-89 pl iB , and in Proceed. Bournemouth Nat. 
Sherring in Proceed. Bournemouth Nat. Sc. Soe. iv. (1913), p. 49, pl. i, ii. 
