OCT. — MAU, 1858-59.] Crystalline Limestone. 



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vertical, so that the vertical extent of the limestone may in all 

 probability be very great. 



Immediately adjoining the main band on its Northern side is a 

 thick bed of quartz rock, and on the Southern is a bed of irregu- 

 larly foliated hornblendic and felspatic gneiss succeeded by a large 

 vein of granite some yards in width. This vein assumes towards 

 its interior the structure of graphic granite. It is here that the 

 change in the direction of the band takes place. 



The limestone is generally of a grey color, but this changes to a 

 white and in some places to pink. Its structure is granularly crys- 

 talline, resembling loaf sugar, at the same time the crystals are not 

 so large as to render the rock friable. The foliation, which, as a 

 rule, is extremely imperfect, is parallel to that of the gneiss, in this 

 case the same as the direction of the band given above. The folia 

 consists of mica and chlorite, these sometimes disappearing altoge- 

 ther and never exceeding an eighth of an inch in width. Fragments 

 of contorted gneiss, and small nests of quartz, chlorite and calc spar 

 occur in it to very small extent, while in places the limestone itself 

 appears to have been squeezed in between the folia of the gneiss 

 and separated into lenticular patches. 



At Mootum the band of limestone is nearly a mile in length, 

 but not so broad nor so much of it seen, as that at Naivailie. It 

 presents the same characters, and the rocks of the vicinity are the 

 same as at that place ; the only difference being that the general 

 color is pink and the development of granite not so great. 



As an industrial resource of this district, the occurrence of crys- 

 talline limestone is very important, owing to its being useful as a 

 building material in the form of stone, marble, or lime. In the 

 present case, the uniformly close texture, the pleasing colors and 

 semi-transiucency, and the comparative freedom from foreign mat- 

 ters, are qualities which render it peculiarly well adapted for these 

 different purposes. I had some of the light grey limestone burnt 

 by the chunam-maker of the place, and specimens of different colors 

 roughly polished in Trichinopoly ; and the results were most satis- 

 factory. The marble is fine grained and clouded, while the colours 

 come out clear and decided ; the lime was of excellent quality. 



