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passing out of the more ferruginous beds of sand and clay. As 

 some of these, the marl stratum for instance, contain a notable 

 proportion of the phosphate of iron, we discover whence the bog 

 ore is contaminated with phosphoric acid, producing a cold short 

 iron. The source of the ore accounts for the interesting fact that, 

 after being dug, the deposit is again renewed after a series of 

 years. In some places, the requisite period does not exceed 

 twenty years. It is essential to the continual deposition of the 

 ore, that the soil in which it is precipitated should not be drained, 

 but that it should be incessantly washed by the ferruginous 

 springs. Where the water from these is enabled readily to 

 escape, and the surface of the ore laid bare and exposed to the 

 rains, the oxide of iron vanishes almost as rapidly as it before 

 accumulated. The lumps retain, it is true, the cellular struc- 

 ture of bog ore, but the matter left consists almost entirely of the 

 more earthy portions, from the solvent power of rain water for 

 oxide of iron in the loosely cohering slate in which it exists in 

 the ore. The rain water seems to owe its capacity of dissolving 

 the iron in the ore to the small quantity of carbonic acid which 

 it collects in its passage through the atmosphere. 



We derive one important hint from these facts: namely, that 

 those who make use of this variety of ore, should avoid keeping 

 large accumulations exposed to the weather as we so frequently 

 witness at the furnaces in the section of the State where the bog 

 ore abounds. It should be dug, in fact, only as it is needed. 



The map accompanying this report, will exhibit the general 

 limits of the several tracts of bog ore, both those confined to the 

 greensand region, and those of far greater extent which occur in 

 the wide sandy country lying between it and the ocean. While 

 the areas represented on the map embrace all the deposits of 

 magnitude and importance, they are not to be regarded as con- 

 taining the bog ore throughout every portion of their surface. 

 On the contrary, the mineral lies principally along the borders of 

 the main streams and their tributaries, and in the beds of those 

 extensive swamps and wet meadows, with which, owing to the 

 sluggishness of their waters, they are generally surrounded. 



Two great deposits, incomparably the largest in the State, 

 border the principal tributaries of the Little Egg Harbour river. 

 The most western of these is connected with the waters of 



