AMERICAN JOURNAL 



OF 



AGRICULTURE AND SCIENCE. 



No. X. FEBRUARY, 1847. 



THE LIMESTONES, AND LIME. 



The subject divides itself into the following parts: 1. The dis- 

 tribution of the limestones in the geological formations. 2. The 

 composition of the limestones. 3. Their origin. 4. The theory 

 of the action of lime as a fertilizer. 5. The uses of lime in the 

 arts. 



I. Distribution of Limestone. 



Limestone, as is well known, occurs as a rock which, when pure, 

 contains lime 56,15, and carbonic acid 43.7. Its specific gravity 

 is 2.74. The rock is distributed through many of the geological 

 formations in the United vStates; but, as in the case of the sand- 

 stones, slates, etc., it cannot be considered as peculiar to any 

 given system of rocks. We speak now of limestone as a mineral 

 simply. When, however, we come to take a special view of it, 

 we must regard every formation which contains a limestone as 

 belonging to it exclusively. Geologically, it has an age and po- 

 sition, and this particular limestone is unknown elsewhere. The 

 same bed of limestone may be widely separated from another bed, 

 and yet can be proved to belong to the same period. Geology 

 then aids the farmer in his search for limestone; and though we 

 can not lay it down as an established law, that the same forma- 

 tion every where will contain its limestone, yet there is so much 

 constancy in its presence in certain formations, that its absence 

 may be considered an exception to a rule, and hence it is a real 

 advantage to know where and in what formations it has been 

 found. It is needless to enter here upon the consideration of the 

 fact, that limestones are unequally developed in the same forma- 

 tion, at distant points. We are not to wonder that it is so; but 

 rather wonder that there is so much constancy in the presence of 

 this rock over such vast areas, and that eras should occur at all, 

 during w^hich the sediments consisted mainly of calcareous matter. 



Vol. V. No. 10. 5 



