1847.] The Limestones, and Lime. 75 



with a prospect of success in all parts of our country which are 

 underlaid with granite, gneiss, mica slate, and hornblende rocks. 

 This view of the matter, however, is contrary to the doctrine 

 which is usually taught, and which has led most inquirers into 

 the belief that the primary masses are destitute of lime. One 

 additional remark we wish to make is, that before they are used 

 for agricultural pnrposes, the presence or absence of magnesia 

 ought to be determined. 



III. Origin of Limestone. 



Remarkable as it may now seem to us, the idea has been ad- 

 vanced by distinguished geologists, that limestone was an animal 

 secretion, not perhaps intending to carry the idea so far as to 

 consider it as an actual creation by animals, but as a new forma- 

 tion by a combination of preexisting elements. The opinion 

 seems to have been founded on the conclusion, that limestone is 

 extremely scarce in the primary rocks, and that it increases in the 

 later formations in the direct proportion in M'hich animal beings 

 themselves increased; for instance, limestone is very common in 

 all the later rocks, the lias and cretaceous systems, and the tertiary, 

 large and thick beds often occurring in almost every country, which 

 are made up of calcareous matter, of which a large proportion 

 consists of shells, the coverings of animals, which are composed 

 of carbonate of lime principally. But the conclusions of the ge- 

 ologists are erroneous, as will be observed from the foregoing 

 statements; for, if they are true, there is no deficiency of lime- 

 stone in the earliest formationsof the globe. 



Leaving out of vjew then the notion that lime or limestone has 

 not an animal origin, we are thrown back at once upon the more 

 rational idea, that it originated, like all other earths and rocks, 

 by the same power and force, and at the same time; or in other 

 words, that it is coeval with granite, gneiss, and other rocks 

 which are called primary. With them it was created, and it ap- 

 pears every where by their side, lying either in parallel position, 

 or traversing them as veins. It lies also in many places beneath 

 granitic beds, and under circumstances which show clearly that 

 in those instances its age is equally great; or according to the 

 rules of interpretation which are acknowledged as authoritative, 

 it existed prior to those beds. In respect, however, to the prior 

 existence of primary rocks, especially the unstratified ones, we 

 have no means of determining the ages of individual masses; for 

 even in the case of superposition, it may be inferred that it is ac- 

 cidental; that if we could penetrate deeply into the bowels of 

 the earth, we might find the superior mass the inferior one. All 

 we can say is, that the last change which these rocks have un- 

 dergone has placed the granite in a position superior to the 

 limestone. 



