On Salt Marsh. 263 



that the turf will not be fit for the bulk of a bank, 

 though the salt grass sod is better than any thing else for 

 facing. 



3d. What will be the probable effect of storm tides; 

 as they may overtop a low bank, or bear a weak one in- 

 to the ditch ? The last inquiry, which perhaps should 

 be first, is particularly necessary in situations where no 

 certain limits can be assigned to the tide at its height. 

 On bays there are large tracts of good marsh, but some of 

 them so exposed to storms that the greatest care must 

 be had to considerations of the size, materials, and cost, 

 of a suitable bank ; the nature of the beach at high and 

 low water ; whether it be shelving or abrupt in its de- 

 scent ; whether it be composed of sand, gravel, or mud ; 

 and whether the marsh gains upon the bay or the bay on 

 the marsh ? Opposite to some marshes there are high 

 mounds of sand or gravel thrown by the surf, whose 

 materials sink at the reflux of the wave ; they cannot 

 float over the marsh as particles of mud in diffusion 

 would, but are left at the edge, as high as any storm tide 

 casts them ; thus forming a natural defence to the marsh, 

 sufficient for its protection against all common tides. 

 This natural mound, however, is sometimes destructive, 

 at others defensive, to the meadow ; defensive, where 

 there are creeks from the upland that ebb and flow 

 in their connexion with the bay ; for, in this case, 

 the back water may be collected, at any time, to force 

 a passage, through which to drain the meadow, at low 

 tide ; it is destructive, where there is no creek rising 

 in the fast land, for the natural mound keeps all the 

 rain water from falling into the bay ; and though a drain 

 may be dug to carry off the water, through the beach to 



