MARSHES. 23 



The red marsh, though varying somewhat in quality, is the best soil^ 

 in the region, and much of it compares favourably with the most 

 celebrated alluvial soils of the old and new Avorlds. The following 

 analysis of recently deposited marsh mud from Truro, will serve to 

 show the composition of this kind of soil : — 



Moisture, ..... -5 



Organic matter, . . . .1*5 



Chlorine, ) i^ -095 



a 1 ' >■ as common salt, . . , , ^ 



boda, j ' -lis 



Potash, -013 



Sulphuric Acid, ) '07 3 



T • ' /- as gypsum, . . „ „ , 



Lime, j °''^ ' -061 



Alumina, ..... '005 



Magnesia, ..... '004 



Carbonate of Lime, . . . 3 "60 



Oxide of Iron, .... 2'74 



Alumina, . . . . .1-20 



■^ Magnesia, . . . . . -11 



Soda and Potash, .... '8 



Phosphoric Acid, .... '09 



Silicious Sand (very fine), . . 88*00 



Soluble in Water. 



Soluble in 

 Hydrochloric Acid. 



So valuable is this soil, though nearly destitute of organic matter, 

 that it is found profitable to cart it u pon the uplaiid as a manure. Its 

 best varieties have now been cropped without manure for more than 

 two centuries, without becoming unproductive ; though there can be 

 no question that under this treatment a gradual diminution of its 

 fertility is perceptible. The weakest point of the marsh land, judging 

 from the above analysis, is its small proportion of phosphates. It is 

 probable, however, that this is in part compensated by the presence of 

 fish bones and other matters of organic origin, which do not appear 

 in an analysis. Yet I have no doubt that the cheapest manure for 

 failing marsh will be found to be bone dust or guano, which, by sup- 

 plying phosphates, will restore it nearly to its original condition. 

 There seems no reason to suppose that a soil with the fine mixture of 

 mineral ingredients present in the marsh mud, requires any artificial 

 supply of ammoniacal matters. Draining is well known to be essen- 

 tial to the fertility of the marshes, and many valuable tracts of this 

 land are now in an unproductive condition from its neglect. The 

 fertility of failing marsh may also be restored by admitting the sea to 

 cover it with a new deposit. This remedy, however, involves the loss 

 of several crops, as some years are require 1 to remove from the new 

 soil its saline matter. It is, however, observed, that in some situations 

 the newly diked marsh produces spontaneously a crop of couch grass 



