ECONOMICAL GEOLOGY. 93 



rapidly filled up by opening ditches, and giving a free 

 channel to them. Several years ago the marshes on Den- 

 nis Creek were banked in, and it is said they sunk three 

 feet or more. The bank has since been broken, and now 

 they are filled with mud up to high-water mark. I have 

 been informed by some owners of marshes, that they can 

 lay an inch of mud on their meadows in a year. In the 

 settled marshes, they must have filled up at a much more 

 rapid rate than this. The settling arises from the decay 

 of vegetable matter which has been drained and exposed 

 to the action of the air ; and as this decay does not go on 

 below the water-level, it is probable the marshes which 

 have been filled up in the way mentioned above, are per- 

 manently improved. 



In places where the tide-water is too clear to form a^y 

 deposit of mud, the marshes may still be improved by 

 covering them with a thin layer of clay or loam from the 

 upland. An excellent piece of meadow, improved in this 

 way, was seen on the farm of Judge Holmes, at Cape May 

 Court House. It had received a coating of twenty or 

 thirty loads per acre of sandy loam, from an adjacent 



knoll. 



3. The marshes which have muck bottoms are those 

 which have been originally swamp, and have been brought 

 to the tide-level by the subsidence of the land. A con- 

 siderable portion of the marsh on the Bay-shore, and some 

 of those which are shallow and near the upland on the 

 sea-shore, are of this kind. These marshes do not settle 

 as rapidly as those with a turf or peat bottom, and can 

 be more easily improved. Dressings of loam or clay will 



