208 TPIE FISHERIES OF THE UNITED STATES. 



Tills mud, says Professor Johnson, contains, in fertilizing elements, the small amounts of nitrogen, lime, magnesia, soda, potash, 

 chlorine, and sulphuric acid given In the analysis, altogether amounting to about 2^ per cent, of the total. But stable manure — the 

 standard fertilizer — contains about the same amount of plant-food, and of the same kinds, except that it has less suljihuric and more 

 plioHiiboric acid, less soda and more potash. The mud, when used judiciously, will prove an excellent fertilizer. Doubtless other samples 

 might contain more phosphates. In any case, the mud, used copiously, together with fish, which are rich In nitrogen and phosjihates, 

 and with seaweed, which contains abundant potash, will supply all the jjlant-food that crops require, and serve to maintain or increase 

 fertility of the soil to the fullest degree. Tlie oidy drawback to the use of the marine mud lies In the considerable proportion of solnlile 

 salts, mostly common salt, which it contains, being nearly 1 per cent. If thrown out in heaps and exposed to the rain this suit will be 

 mostly removed. The mud may also be applied directly to the root-crops or grass in moderate quantities, without damage, if well 

 distributed. As an amendment the fine mud must have an excellent efi'ect on coarse-textured soils. 



Shell-heaps and their use. — lu Florida and the Gulf states, the best farms and gardens are those located 

 upon the shell-mound.s, where the finest trees grow ; and in the northern states these old heaps have long been 

 resorted to by farmers as a storehouse of top-dressing for their fields. The immense banks at Damariscotta, 

 described in the chapter on the Gulf of Maine, are constantly utilized for this purpose. The shells are first 

 burned, and the remains of various rude kilns exist, one of which greatly excited the antiquarians who first 

 exhumed it, who were sure they had hit upon an aboriginal, i^rehistoric home, until they found half a brick in the 

 bottom. Within a few years Mr. Charles Metcalf has built a more substantial kiln and has burned there a large 

 quantity of shells; but he was unable to give me any estimate of what this manure cost him, or the probable 

 value of the heaps, if used for this purpose. He had never sold any shell-lime either for use in mortar or on the 

 fields. Hereafter these deposits may prove an important aid to agriculture in the district, and they are practically 

 inexhaustible. Similar great heaps of half-decayed shells exist in northern New Jersey, from one of which an 

 immense mass of material has been hauled for road-making, and also to be used as ballast in oyster-vessels bound 

 for the Chesapeake bay, where it would be thrown and serve as the best cultch for any spat which might float by. 



