62 QUARTERLYJOURNAL 



FERTILIZERS IN THE ROCKS. 



Our attention in the course of the agricultural survey, has been 

 turned to the character of the rocks as fertilizers of the soil. The 

 first inquiry was — do the rocky masses themselves admit of being 

 applied as manures '? and in the second place, what' elements do 

 they contain which renders them valuable as fertilizers to soils 1 

 In answer to the first question, we have ascertained that some at 

 least of the shales — limestone shales, as they may be called — are 

 of great importance to agriculture. We stated in one of the 

 meetings held at the geological rooms, some of the results of the 

 analysis which we had made : showing that they are rich in saline 

 matter, and mostly free from the astringent salts which are inju- 

 rious to vegetation. These examinations are the first which have 

 been made in this country in this matter, and we propose to pur- 

 sue them. New-York, in every district, except the Atlantic, is rich 

 in the shales, particularly the western, or the wheat growing dis- 

 trict. In order to use these shales, the best mode will be to raise 

 them, throw them into heaps in prepared places and then let them 

 crumble and decompose. The debris of the heaps may be mixed 

 with a compost or with barn-yard manure. If the decomposing 

 matters are astringent, mix them with sufficient lime to neutralize 

 the salt, which will probably be mixtures of the sulphates of iron 

 and alumine ; these will be decomposed, and gypsum will be one 

 of the resulting compounds. In addition to these salts there will 

 be found sulphate of magnesia, which ranks high as a fertilizer. 



Besides the shales, the limestones themselves are deserving of 

 examination ; but, as I have not yet advanced far in this inquiry 

 in regard to them, I merely speak of them in this brief manner, 

 hoping by and by to lay some important results before the agricul- 

 tural community. 



Of the materials which it is possible the fossiliferous limestones 

 may contain, we may state the high probability of their being rich 

 in phosphate of lime. Derived as they all are from primary 

 rocks, all of which are occasionally known to embrace this sub- 

 stance, we can hardly doubt of its presence — especially when we 

 connect it with the fact that much organic matter has been enclo- 



