Tl4:8j 149] CRETACEOUS LIMESTONE. 101 



order to draw the burnt lime. The kilns used ought to be of the "perpetual" 

 kind, where the process is carried on without interruption and, once properly 

 adjusted, goes on evenly, turning out a product always of the same quality. 

 Such, moreover, consume much less fuel than the common ones — an item of 

 importance in the prairies. There can be no doubt that if the kilns were im- 

 proved, lime of good quality could be made in numerous localities where it is 

 now deemed impracticable, after a trial with the ordinary kiln. In burning- 

 lime for agricultural purposes, especially, any other than a perpetual kiln ren- 

 ders the article too expensive. 



148. The material of the Rotten Limestone Group in Tisho- 

 mingo county, is generally too impure for lime-burning- ; the purest 

 rock found occurs, probably, on the heads of Twenty Mile Creek, 

 W. and S. of Blackland, and on lower Tishomingo Creek, near 

 the Ripley and Carrollville road. The materials found further N. 

 are generally too clayey for quicklime, but some of them will, no 

 doubt, answer for hydraulic cement. Lime has, it is true, been 

 made in several localities on the cretaceous territory in Tisho- 

 mingo county, but it was from the shells of oysters, (Exogyra cos- 

 tata, Gryphaea convexa and mulabilis), which yield a very strong 

 lime. The supply of these, however, is too small to be of more 

 than very local importance. 



I am not aware that any rock sufficiently pure for lime-burning, 

 exists in Itawamba county — none, at least, E. of Old Town Creek. 

 W. of the same, on the prairies and "Chickasaw Old Fields" of 

 Pontotoc, the rock is very similar to that of Monroe. 



149. Good lime is made at Camargo, where a ledge of hard 

 rock yields white lime for plastering, while the underlying softer 

 strata furnish common mortar. At Okalona, also, lime is made : 

 an analysis of the rock, taken from a cistern here, cave the follow- 



result : 



OKALONA ROTTEN LIMESTONE. 



oluble Matter 10.90;; 



Potash 0.248 



Soda 0.320 



Lime 45.791 



Magnesia 0.877 



Peroxide of Iron 1.421 



Alumina 1.957 



Carbonic Acid 35.725 



Water 2.840 



100.082 



One cwt. of this rock will therefore yield about 61 lbs. of burnt 

 lime, containing about 15 lbs. of impurities which, while causing 

 it to slake with less energy, must impart to it some hydraulic prop- 

 erties. 



It would seem advisable, therefore, not to slake and mix into mortar very 

 large quantities of this lime, at any one time, and to use it, when made, as 

 rapidly as possible. In this manner the hydraulic properties, which would 



