LIMESTONE. 11 



composed of shattered parts of shells, and marine 

 substances, greatly consumed and imperfect, em- 

 bedded in a coarse, gray, sparry compound ; an 

 ocean deposit, not a fabrication, and consequently 

 has more impurities in its substance than that of 

 insect formation : it contains about 



Carbonate of lime . . 73 



Magnesia . . . . .11 



Clay . , . . . 14 



Silex . .... 2 



"Too 



These two specimens so clearly prove that the 

 original materials of their substance were derived 

 from the deep, that no further arguments need be 

 advanced to support this fact as to our limestone. 

 The former is^ perhaps, the mountain limestone of 

 Werner; the latter a variety of dolomite. Our 

 other quarries, as well as the lower strata of the 

 above, present no such indications of animal forma- 

 tion, and they are probably sediment arising from a 

 minute division of shelly bodies, now indurated by 

 time and superincumbent pressure, and become a 

 coarse-grained marble. Our limestone thus appear- 

 ing not to be contaminated with any great portion 

 of magnesian earth, it may be used for all agri- 

 cultural purposes with advantage. Many detached 

 blocks of limestone are found about us, having 

 broken' shelly remains, and the joints of the encri- 

 nite, greatly mutilated, embedded in them. Irregu- 

 larly wandering near the lime-ridge is a vein of im- 

 pure sandy, soil, covering a coarse-grained siliceous 



