82 The Limestones, and Lime. 



Winslow limestone; color blue, mixed with slate. 

 Analysis. 



[Feb. 



Carbonate of lime, 

 Insoluble, 

 Oxide of iron. 



77.8 



20.6 



1.6 



100. 

 Per cent of lime, 43.7. The quality of the lime is good. It is 

 interstratifled with slate, which is equivalent, we believe, to the 

 Taconic slate of New York. 



5. Composition of the Taconic Limestones of Rhode Island — by 

 Jackson. 



Limestone of Smithfield, Rhode Island. 



Harris Quarry. 

 Carbonate of lime, - 92.4 

 Carbonate of magnesia, 1.2 

 Insoluble matter, - 6. 



99.6 

 Lime, 52 per cent. 



Carbonate of lime, 

 Carbonate of magnesia. 

 Insoluble matter, 



Arnold Quarry. 

 50.6 

 44.4 

 3.8 



Dexter Quarry. 



94.8 







1.6 



96.4 



53.4 per cent. 

 Sp. gravity, 2.96. 



Angell Quarry. 



97.6 







1.0 



98.8 98.6 



Pure lime, 28.5 Lime, 54.9 



It will be observed that the presence of magnesia is by no 

 means uniformly present in the Taconic limestones, or that where 

 it is present the amount is at all uniform; the same fact will be 

 noticed also in the primary limestones, and while its presence is 

 indicated by the existence of serpentine in the rock, still it is by 

 no means certain that it is in considerable quantities. 



The analysis of the Vermont limestones shew also, that while 

 magnesia is often ])resent in the white and clouded marbles, yet 

 it is proved by analysis that it is often absent too in the granular 

 varieties, v.hich pass under the name of dolomites. They resem- 

 ble the Berkshire marbles, several analyses of which have been 

 already given. 



(7b be continued.) 



